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1

Cellular responses to environmental DNA damage  

Science Conference Proceedings (OSTI)

This volume contains the proceedings of the conference entitled Cellular Responses to Environmental DNA Damage held in Banff,Alberta December 1--6, 1991. The conference addresses various aspects of DNA repair in sessions titled DNA repair; Basic Mechanisms; Lesions; Systems; Inducible Responses; Mutagenesis; Human Population Response Heterogeneity; Intragenomic DNA Repair Heterogeneity; DNA Repair Gene Cloning; Aging; Human Genetic Disease; and Carcinogenesis. Individual papers are represented as abstracts of about one page in length.

Not Available

1994-08-01T23:59:59.000Z

2

Modular Systems Biology applied to TGFbeta and DNA Damage Response...  

NLE Websites -- All DOE Office Websites (Extended Search)

Modular Systems Biology applied to TGFbeta and DNA Damage Response Signaling following Low Dose Radiation Francis Cucinotta NASA Johnson Space Center Abstract Modular systems...

3

Connecting Chromatin Modifying Factors to DNA Damage Response  

E-Print Network (OSTI)

Abstract: Cells are constantly damaged by factors that can induce DNA damage. Eukaryotic cells must rapidly load DNA repair proteins onto damaged chromatin during the DNA damage response (DDR). Chromatin-remodeling complexes use the energy from ATP hydrolysis to remodel nucleosomes and have well-established functions in transcription. Emerging lines of evidence indicate that chromatin-remodeling complexes are important and may remodel nucleosomes during DNA damage repair. New studies also reveal that ATP-dependent chromatin remodeling is involved in cell cycle progression, signal transduction pathways, and interaction and modification of DDR-related proteins that are specifically and intimately connected with the process of DNA damage. This article summarizes the recent advances in our understanding of the interplay between chromatin remodeling and DNA damage response.

Weiwei Lai; Hongde Li; Shuang Liu; Yongguang Tao

2013-01-01T23:59:59.000Z

4

Role of ATM kinase in ionizing radiation induced DNA damage response...  

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ATM kinase in ionizing radiation induced DNA damage response in human neural stemprogenitor cells and differentiated cell types Adayabalam Balajee Columbia University Medical...

5

Low Dose Radiation Induced DNA Damage Signaling and Repair Responses in  

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Induced DNA Damage Signaling and Repair Responses in Induced DNA Damage Signaling and Repair Responses in Human 3-Dimensional Skin Model System Yanrong Su, Jarah Meador and Adayabalam S. Balajee Center for Radiological Research, College of Physicians and Surgeons, Columbia University, 630 West, 168th Street, New York, NY 10032. Exposure to ionizing radiation (IR) inflicts a wide variety of lesions in the genomic DNA. Among them, DNA double strand break (DSB) is considered to be the critical lesion for most of the deleterious radiation effects including carcinogenesis. Much of our knowledge on induction and repair kinetics of DSB has come from studies in two dimensional cell culture systems. However, the damage signaling and repair responses to DSB in tissue microenvironment are largely unknown. Knowledge of tissue responses to

6

Modular Systems Biology applied to TGFbeta and DNA Damage Response Signaling following Low Dose Radiation  

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Modular Systems Biology applied to TGFbeta and DNA Damage Response Signaling following Modular Systems Biology applied to TGFbeta and DNA Damage Response Signaling following Low Dose Radiation Francis A. Cucinotta 1 , Yongfeng Li 2 , Minli Wang 2 , Claudio Carra 2 , Janice Pluth 3 , and Peter O'Neill 4 1 NASA Johnson Space Center, Houston, TX 2 U.S.R.A. Division of Life Sciences, Houston TX 3 Lawrence Berkeley National Laboratory, Berkeley CA 4 Oxford University, Oxford UK Abstract: Modular systems biology (MSB) describes the complexity of biological systems using well defined modules that represent distinct biological response pathways or sub-systems within pathways. We review mathematical concepts from control theory that can be used to identify and construct well defined modules for describing complex biological processes. The DNA damage response and TGFbeta/Smad signaling are two important response pathways following

7

Interplay between Np95 and Eme1 in the DNA damage response  

Science Conference Proceedings (OSTI)

Mus81 (methyl methansulfonate UV sensitive clone 81) and Eme1 (essential meiotic endonuclease 1, also known as MMS4) form a heterodimeric endonuclease that is critical for genomic stability and the response to DNA crosslink damage and replication blockade. However, relatively little is known as to how this endonuclease is regulated following DNA damage. Here, we report mammalian Eme1 interacts with Np95, an E3 ubiquitin ligase that participates in chromatin modification, replication-linked epigenetic maintenance and the DNA damage response. Np95 and Eme1 co-localize on nuclear chromatin following exposure of cells to camptothecin, an agent that promotes the collapse of replication forks. The observed co localization following DNA damage was found to be dependent on an intact RING finger, the structural motif that encodes the E3 ubiquitin ligase activity of Np95. Taken together, these findings link Mus81-Eme1 with the replication-associated chromatin modifier functions of Np95 in the cellular response to DNA damage.

Mistry, Helena; Gibson, Lianne; Yun, J.W.; Sarras, Haya; Tamblyn, Laura [Department of Pharmacology, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8 (Canada); McPherson, John Peter [Department of Pharmacology, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8 (Canada)], E-mail: peter.mcpherson@utoronto.ca

2008-10-24T23:59:59.000Z

8

S1219 residue of 53BP1 is phosphorylated by ATM kinase upon DNA damage and required for proper execution of DNA damage response  

SciTech Connect

53BP1 is phosphorylated by the protein kinase ATM upon DNA damage. Even though several ATM phosphorylation sites in 53BP1 have been reported, those sites have little functional implications in the DNA damage response. Here, we show that ATM phosphorylates the S1219 residue of 53BP1 in vitro and that the residue is phosphorylated in cells exposed to ionizing radiation (IR). Transfection with siRNA targeting ATM abolished IR-induced phosphorylation at this residue, supporting the theory that this process is mediated by the kinase. To determine the functional relevance of this phosphorylation event, a U2OS cell line expressing S1219A mutant 53BP1 was established. IR-induced foci formation of MDC1 and {gamma}H2AX, DNA damage signaling molecules, was reduced in this cell line, implying that S1219 phosphorylation is required for recruitment of these molecules to DNA damage sites. Furthermore, overexpression of the mutant protein impeded IR-induced G2 arrest. In conclusion, we have shown that S1219 phosphorylation by ATM is required for proper execution of DNA damage response.

Lee, Haemi; Kwak, Hee-Jin; Cho, Il-taeg [Reseach Institute, National Cancer Center, 111 Jungbalsan-ro, Ilsandong-gu, Goyang, Gyeonggi, 410-769 (Korea, Republic of); Park, Seok Hee [Department of Biological Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Lee, Chang-Hun [Reseach Institute, National Cancer Center, 111 Jungbalsan-ro, Ilsandong-gu, Goyang, Gyeonggi, 410-769 (Korea, Republic of)], E-mail: chlee@ncc.re.kr

2009-01-02T23:59:59.000Z

9

STOCHASTIC MODELS OF SPACE RADIATION DNA DAMAGE RESPONSES AND CANCER RISKS  

NLE Websites -- All DOE Office Websites (Extended Search)

STOCHASTIC MODELS OF SPACE RADIATION DNA DAMAGE STOCHASTIC MODELS OF SPACE RADIATION DNA DAMAGE RESPONSES AND CANCER RISKS Francis A. Cucinotta 1 , Janice M. Pluth 2 , Artem Ponomarev 3 , Shaowen Hu 3 , Jennifer Anderson 4 , Jane Harper 4 , and Peter O'Neill 4 1 NASA Lyndon B. Johnson Space Center, Houston TX, USA; 2 Lawrence Berkeley National Laboratory, Berkeley CA, USA; 3 U.S.R.A., Division of Life Sciences, Houston TX, USA; 4 MRC Radiation and Genome Stability Unit, Harwell, Didcot, UK Abstract: On space missions astronauts are exposed to a steady flux of galactic cosmic rays (GCR) consisting of high-energy protons and heavy ions. In the next decades long- term missions of up to 200 days to the Earth's moon and 1100 days to Mars are planed by NASA where cumulative doses will not be low (>100 mSv) albeit dose-

10

Genome-wide single-cell-level screen for protein abundance and localization changes in response to DNA damage in S. cerevisiae  

E-Print Network (OSTI)

An effective response to DNA damaging agents involves modulating numerous facets of cellular homeostasis in addition to DNA repair and cell-cycle checkpoint pathways. Fluorescence microscopy-based imaging offers the ...

Mazumder, Aprotim

11

DNA Damage Pathways: Low Dose Response and Cross-Talk in TGFβ and ATM  

NLE Websites -- All DOE Office Websites (Extended Search)

Damage Pathways: Low Dose Response and Cross-Talk in TGFβ and ATM Damage Pathways: Low Dose Response and Cross-Talk in TGFβ and ATM Signaling Peter O'Neill University of Oxford Abstract The ATM and TGFbeta signal transduction pathways are essential to cellular and tissue control responses to ionizing radiation (IR) and aberrant modifications to these pathways are extensive in cancer. We hypothesize that the ATM and TGFbeta signaling pathways are fully induced at high doses of acute low-LET radiation, whereas only partially induced at low doses. As a consequence of partial stimulation of these pathways important questions arise not only on the validity of the linear no-threshold assumption used in radiation regulations, but also on our ability to extrapolate experimental and human epidemiology data from high to low doses. The

12

The role of mismatch repair and recombination in cellular responses to the DNA damaging anticancer drug Cisplatin  

E-Print Network (OSTI)

Cisplatin (cis-diamminedichloroplatinum(ll)) is a successful DNA-damaging anticancer drug used in the treatment of testicular, ovarian and other tumors. In the past decade, several mutually non-exclusive hypotheses have ...

Zdraveski, Zoran Z. (Zoran Zare), 1969-

2002-01-01T23:59:59.000Z

13

Regulation of epithelial-mesenchymal transition and DNA damage responses by singleminded-2s  

E-Print Network (OSTI)

Virtually all signaling pathways that play key roles in development such as the transfroming growth factor (TGF)-beta, notch, and wnt pathways also influence tumor formation, implying that cancer is in a sense development gone awry. Therefore, identification and elucidation of developmental pathways has great potential for generating new diagnostic tools and molecular therapy targets. Singleminded-2s (SIM2s), a splice variant of the basic helilx-loop-helix / PER-ARNT-SIM (bHLH/PAS) transcriptional repressor Singleminded-2, is lost or repressed in approximately 70% of human breast tumors and has a profound influence on normal mammary development. In order to gain a better understanding of the mechanisms by which SIM2s restricts malignant transformation and progression in breast cancer, we depleted SIM2 RNA in MCF-7 cells using a retroviral shRNA system and examined gene expression and functional abilities of the SIM2-depleted MCF-7 cells (SIM2i) relative to a control MCF line expressing a non-specific scrambled shRNA (SCR). Depletion of SIM2 resulted in an epithelial-mesenchymal transition (EMT)-like effect characterized by increased migration and invasion, altered morphology, and loss of epithelial markers concomitant with gain of mesenchymal markers. The root of this effect may be loss of SIM2- mediated repression of the E-cadherin repressor slug, as SIM2 is able to bind and repress transcription from the slug promoter, and slug expression is dramatically elevated in SIM2i MCF-7 cells. Consistent with the previously established role of slug in resistance to various cancer therapies, SIM2i cells are resistant to the radiomimetic doxorubicin and appear to have elevated self-renewal capacity under certain conditions. Intriguingly, SIM2 protein levels are elevated by treatment with DNA damaging agents, and SIM2 interacts with the p53 complex via co-regulation of specific p53- target gene such as p21/WAF1/CIP1. These results provide a plausible mechanism for the tumor suppressor activity of SIM2, and provide insight into a novel tumor suppressive transcriptional circuit that may have utility as a therapeutic target.

Laffin, Brian Edward

2008-08-01T23:59:59.000Z

14

DNA damage responses in the context of the cell division cycle  

E-Print Network (OSTI)

and binds to human Chk1 235 61. Strategy for the design of Rad9-h/ggMCPH1 hybrid constructs 237 LIST OF DIAGRAMS 1. Possible mechanisms of action of the CMG helicase complex during DNA unwinding Pg... helicase. Indeed, the MCM complex remains associated with the fork during S-phase and plays a role ahead of the fork as an helicase to unwind the DNA duplex, with a 3 to 5 polarity shown for the archaeal MCM (Kelman et al., 1999; Chong et al., 2000...

Giunta, Simona

2010-11-16T23:59:59.000Z

15

Non-linear DNA damage response to low-dose ionizing radiation...  

NLE Websites -- All DOE Office Websites (Extended Search)

the spatiotemporal response in ATM- or DNApkcs-deficient cells or as a function of chromatin territory, to extend the work done by the Karpen Lab using the Drosophila model...

16

Microsoft Word - CosteNon-linear DNA damage response to low-dose...  

NLE Websites -- All DOE Office Websites (Extended Search)

the spatiotemporal response in ATM- or DNApkcs-deficient cells or as a function of chromatin territory, to extend the work done by the Karpen Lab using the Drosophila model...

17

Links between persistent DNA damage, genome instability, and aging  

NLE Websites -- All DOE Office Websites (Extended Search)

Links between persistent DNA damage, genome instability, and aging Links between persistent DNA damage, genome instability, and aging William Dynan Medical College of Georgia Abstract There is considerable overlap between cellular and molecular changes that occur in response to low doses of ionizing radiation and those that occur during aging. Both processes are characterized by accumulation of persistent DNA damage ("wear and tear" on the genome), accumulation of protein and lipid oxidation products, loss of regenerative capacity at the cellular and tissue level, and increased incidence of cancer. These observations support a hypothesis that exposure to low-dose ionizing radiation accelerates normal, aging-related tissue changes. We have investigated this hypothesis using a genetically tractable model organism, the Japanese medaka fish. The medaka is a whole-animal vertebrate

18

Clustered DNA Damage Spectrum in Primary Human Hematopoietic...  

NLE Websites -- All DOE Office Websites (Extended Search)

94805 Villejuif Cedex France Clustered DNA Damages Induced by Low Radiation Doses Irradiation of cells with low doses of X- or -rays induces clustered damages in mammalian...

19

Regulation of DNA damage tolerance : studies of the translesion synthesis DNA ploymerase eta in Saccharomyces cerevisiae  

E-Print Network (OSTI)

All organisms must control the effects of DNA damage to protect the integrity of their genomes. In addition to DNA repair, this requires DNA damage tolerance pathways, which allow the continuation of essential processes ...

Woodruff, Rachel Van Etten

2008-01-01T23:59:59.000Z

20

DNA repair decline during mouse spermiogenesis results in the accumulation of heritable DNA damage  

Science Conference Proceedings (OSTI)

The post-meiotic phase of mouse spermatogenesis (spermiogenesis) is very sensitive to the genomic effects of environmental mutagens because as male germ cells form mature sperm they progressively lose the ability to repair DNA damage. We hypothesized that repeated exposures to mutagens during this repair-deficient phase result in the accumulation of heritable genomic damage in mouse sperm that leads to chromosomal aberrations in zygotes after fertilization. We used a combination of single or fractionated exposures to diepoxybutane (DEB), a component of tobacco smoke, to investigate how differential DNA repair efficiencies during the three weeks of spermiogenesis affected the accumulation of DEB-induced heritable damage in early spermatids (21-15 days before fertilization, dbf), late spermatids (14-8 dbf) and sperm (7- 1 dbf). Analysis of chromosomalaberrations in zygotic metaphases using PAINT/DAPI showed that late spermatids and sperm are unable to repair DEB-induced DNA damage as demonstrated by significant increases (P<0.001) in the frequencies of zygotes with chromosomal aberrations. Comparisons between single and fractionated exposures suggested that the DNA repair-deficient window during late spermiogenesis may be less than two weeks in the mouse and that during this repair-deficient window there is accumulation of DNA damage in sperm. Finally, the dose-response study in sperm indicated a linear response for both single and repeated exposures. These findings show that the differential DNA repair capacity of post-meioitic male germ cells has a major impact on the risk of paternally transmitted heritable damage and suggest that chronic exposures that may occur in the weeks prior to fertilization because of occupational or lifestyle factors (i.e, smoking) can lead to an accumulation of genetic damage in sperm and result in heritable chromosomal aberrations of paternal origin.

Marchetti, Francesco; Marchetti, Francesco; Wryobek, Andrew J

2008-02-21T23:59:59.000Z

Note: This page contains sample records for the topic "dna damage response" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

DNA Repair Decline During Mouse Spermiogenesis Results in the Accumulation of Heritable DNA Damage  

Science Conference Proceedings (OSTI)

The post-meiotic phase of mouse spermatogenesis (spermiogenesis) is very sensitive to the genomic effects of environmental mutagens because as male germ cells form mature sperm they progressively lose the ability to repair DNA damage. We hypothesized that repeated exposures to mutagens during this repair-deficient phase result in the accumulation of heritable genomic damage in mouse sperm that leads to chromosomal aberrations in zygotes after fertilization. We used a combination of single or fractionated exposures to diepoxybutane (DEB), a component of tobacco smoke, to investigate how differential DNA repair efficiencies during the three weeks of spermiogenesis affected the accumulation of DEB-induced heritable damage in early spermatids (21-15 days before fertilization, dbf), late spermatids (14-8 dbf) and sperm (7-1 dbf). Analysis of chromosomal aberrations in zygotic metaphases using PAINT/DAPI showed that late spermatids and sperm are unable to repair DEB-induced DNA damage as demonstrated by significant increases (P<0.001) in the frequencies of zygotes with chromosomal aberrations. Comparisons between single and fractionated exposures suggested that the DNA repair-deficient window during late spermiogenesis may be less than two weeks in the mouse and that during this repair-deficient window there is accumulation of DNA damage in sperm. Finally, the dose-response study in sperm indicated a linear response for both single and repeated exposures. These findings show that the differential DNA repair capacity of post-meioitic male germ cells has a major impact on the risk of paternally transmitted heritable damage and suggest that chronic exposures that may occur in the weeks prior to fertilization because of occupational or lifestyle factors (i.e, smoking) can lead to an accumulation of genetic damage in sperm and result in heritable chromosomal aberrations of paternal origin.

Marchetti, Francesco; Marchetti, Francesco; Wyrobek, Andrew J.

2007-12-01T23:59:59.000Z

22

Damages to DNA that result in neoplastic transformation  

SciTech Connect

Some topics discussed are: correlation between carcinogens and mutagens; defective DNA repair in uv-damaged xeroderma pigmentosum cells; analysis of nucleotide damage to DNA following exposure to chemicals or radiations; photoreactivation in uv-irradiated Escherichia coli; tumor development in fish; excision repair as an aid in identifying damage; detection of excision repair; role of endonucleases in repair of uv damage; and alkylation products and tumors. (HLW)

Setlow, R.B.

1975-01-01T23:59:59.000Z

23

Induction of DNA Damage by Low Dose PET scans  

NLE Websites -- All DOE Office Websites (Extended Search)

Induction of DNA Damage by Low Dose PET scans Induction of DNA Damage by Low Dose PET scans Douglas Boreham McMaster University Abstract This research is focused on assessing the radiation risk associated with positron emission tomography (PET) scans. It has been suggested that low dose medical imaging, such as PET scans, carry an added biological risk because they expose the patient to ionizing radiation. PET scanning is an increasingly used nuclear medicine procedure that requires the administration of isotope 18F-fluorodeoxyglucose (18F-FDG, E=250 keV β and 511 keV γ) and results in an effective dose to the patient ranging from 7-22 mSv. The radiation induced DNA damage associated with a PET scan was studied in 7-9 week old female wild type Trp53 +/+ mice. Mice were given a PET scan with 18F-FDG and the biological response was assessed in bone marrow using

24

Persistent DNA damage foci, cellular senescence and low dose radiation  

NLE Websites -- All DOE Office Websites (Extended Search)

Persistent DNA damage foci, cellular senescence and low dose radiation Persistent DNA damage foci, cellular senescence and low dose radiation Denise Munoz 1 , Albert Davalos 1 , Francis Rodier 1 , Misako Kawahara 1 , Judith Campisi 1,2 and Steven Yannone 1,3 1 Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Mailstop 84-171, Berkeley CA 94720; 2 Buck Institute for Age Research, 8001 Redwood Boulevard, Novato CA 94945; 3 Corresponding author Ionizing radiation (IR) induced DNA double-strand breaks (DSBs) are cytologically detectable as large nuclear foci that contain phosphorylated histone H2AX (γH2AX), the adaptor protein 53BP1, and several other proteins that participate in the sensing and processing of DNA damage (DNA damage foci). In normal human cells, moderately high IR (0.5-1 Gy) doses cause the rapid appearance of these foci (acute DNA damage foci), which gradually disappear

25

Modulating radiation induced TGFβ and ATM signaling in the DNA damage  

NLE Websites -- All DOE Office Websites (Extended Search)

Modulating radiation induced TGFβ and ATM signaling in the DNA damage Modulating radiation induced TGFβ and ATM signaling in the DNA damage response Jennifer A. Anderson Gray Institute for Radiation Oncology and Biology Abstract Both the ATM and TGFβ signal transduction pathways are essential for cellular and tissue control responses to ionizing radiation and aberrant modifications to these pathways are extensive in cancer. We hypothesize that the ATM and TGFβ signaling pathways are fully induced at high doses of acute low-LET radiation, whereas only partially induced at low doses. Numerous studies have linked the p38 MAPK signaling pathway with the ATM DNA damage response, and others have shown that TGFβ stimulation results in the phosphorylation of p38 MAPK. Our aim is to perturb potential crosstalk between ATM, TGFβ and p38 MAPK at the DNA damage level and

26

Calculation of complex DNA damage induced by ions  

SciTech Connect

This paper is devoted to the analysis of the complex damage of DNA irradiated by ions. The assessment of complex damage is important because cells in which it occurs are less likely to survive because the DNA repair mechanisms may not be sufficiently effective. We study the flux of secondary electrons through the surface of nucleosomes and calculate the radial dose and the distribution of clustered damage around the ion's path. The calculated radial dose distribution is compared to simulations. The radial distribution of the complex damage is found to be different from that of the dose. A comparison with experiments may solve the question of what is more lethal for the cell, damage complexity or absorbed energy. We suggest a way to calculate the probability of cell death based on the complexity of the damage. This work is done within the framework of the phenomenon-based multiscale approach to radiation damage by ions.

Surdutovich, Eugene [Department of Physics, Oakland University, Rochester, Michigan 48309 (United States); Frankfurt Institute for Advanced Studies, Ruth-Moufang-Strasse 1, D-60438 Frankfurt am Main (Germany); Gallagher, David C. [Department of Physics, Oakland University, Rochester, Michigan 48309 (United States); Solov'yov, Andrey V. [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Strasse 1, D-60438 Frankfurt am Main (Germany)

2011-11-15T23:59:59.000Z

27

Low Dose Radiation Research Program: Comparison of DNA Damage...  

NLE Websites -- All DOE Office Websites (Extended Search)

Comparison of DNA Damage Risk from Low-Dose Radiation and Folate Deficiency Arnold C. Huang,1,2 Chantal Courtemanche,1,2 Nicole Kerry,1,2 Susan T. Mashiyama,1,2 Michael Fenech,3...

28

Precision Biochemistry Tracks DNA Damage in Fish  

Science Conference Proceedings (OSTI)

... Like coal-mine canaries, fish DNA can serve as a measure of the biological impact of water and sediment pollutionor pollution clean-up. ...

2012-10-17T23:59:59.000Z

29

Nanofoams Response to Radiation Damage  

Science Conference Proceedings (OSTI)

Conclusions of this presentation are: (1) np-Au foams were successfully synthesized by de-alloying process; (2) np-Au foams remain porous structure after Ne ion irradiation to 1 dpa; (3) SFTs were observed in irradiated np-Au foams with highest and intermediate flux, while no SFTs were observed with lowest flux; (4) SFTs were observed in irradiated np-Au foams at RT, whereas no SFTs were observed at LNT irradiation; (5) The diffusivity of vacancies in Au at RT is high enough so that the vacancies have enough time to agglomerate and thus collapse. As a result, SFTs were formed; (6) The high flux created much more damage/time, vacancies don't have enough time to diffuse or recombine. As a result, SFTs were formed.

Fu, Engang [Los Alamos National Laboratory; Serrano De Caro, Magdalena [Los Alamos National Laboratory; Wang, Yongqiang [Los Alamos National Laboratory; Nastasi, Michael [Nebraska Center for Energy Sciences Research, University of Nebraska-Lincoln, NE 68508; Zepeda-Ruiz, Luis [PLS, Lawrence Livermore National Laboratory, Livermore, CA 94551; Bringa, Eduardo M. [CONICET and Inst. Ciencias Basicas, Universidad Nacional de Cuyo, Mendoza, 5500 Argentina; Baldwin, Jon K. [Los Alamos National Laboratory; Caro, Jose A. [Los Alamos National Laboratory

2012-07-30T23:59:59.000Z

30

RNF8 Transduces the DNA-Damage Signal Via Histone Ubiquitylation And Checkpoint Protein Assembly  

Science Conference Proceedings (OSTI)

DNA-damage signaling utilizes a multitude of posttranslational modifiers as molecular switches to regulate cell-cycle checkpoints, DNA repair, cellular senescence, and apoptosis. Here we show that RNF8, a FHA/RING domain-containing protein, plays a critical role in the early DNA-damage response. We have solved the X-ray crystal structure of the FHA domain structure at 1.35 {angstrom}. We have shown that RNF8 facilitates the accumulation of checkpoint mediator proteins BRCA1 and 53BP1 to the damaged chromatin, on one hand through the phospho-dependent FHA domain-mediated binding of RNF8 to MDC1, on the other hand via its role in ubiquitylating H2AX and possibly other substrates at damage sites. Moreover, RNF8-depleted cells displayed a defective G2/M checkpoint and increased IR sensitivity. Together, our study implicates RNF8 as a novel DNA-damage-responsive protein that integrates protein phosphorylation and ubiquitylation signaling and plays a critical role in the cellular response to genotoxic stress.

Huen, M.S.Y.; Grant, R.; Manke, I.; Minn, K.; Yu, X.; Yaffe, M.B.; Chen, J.

2009-06-01T23:59:59.000Z

31

Translationally Controlled Tumor Protein Protects against DNA Damage in Low  

NLE Websites -- All DOE Office Websites (Extended Search)

Translationally Controlled Tumor Protein Protects against DNA Damage in Low Translationally Controlled Tumor Protein Protects against DNA Damage in Low Dose γ-Irradiated Cells Edouard Azzam New Jersey Medical School Cancer Center Abstract We have previously shown that exposure to low dose/low dose rate γ-rays can protect normal human and rodent cells against oxidative/clastogenic damages induced spontaneously or by a subsequent challenge dose of ionizing radiation. To gain insight into the mechanisms underlying these effects, we used amine-specific isobaric tags for relative and absolute quantitation (iTRAQ)-based approach to identify induced proteolytic events. Intriguingly, the Translationally Controlled Tumor Protein (TCTP) was significantly up-regulated after 10cGy (0.2cGy/h) but not after 4 Gy (1 Gy/min) in several strains of normal human fibroblasts maintained in 2- or

32

Endogenous DNA Damage and Risk of Testicular Germ Cell Tumors  

SciTech Connect

Testicular germ cell tumors (TGCT) are comprised of two histologic groups, seminomas and nonseminomas. We postulated that the possible divergent pathogeneses of these histologies may be partially explained by variable endogenous DNA damage. To assess our hypothesis, we conducted a case-case analysis of seminomas and nonseminomas using the alkaline comet assay to quantify single-strand DNA breaks and alkali-labile sites. The Familial Testicular Cancer study and the U.S. Radiologic Technologists cohort provided 112 TGCT cases (51 seminomas & 61 nonseminomas). A lymphoblastoid cell line was cultured for each patient and the alkaline comet assay was used to determine four parameters: tail DNA, tail length, comet distributed moment (CDM) and Olive tail moment (OTM). Odds ratios (OR) and 95% confidence intervals (95%CI) were estimated using logistic regression. Values for tail length, tail DNA, CDM and OTM were modeled as categorical variables using the 50th and 75th percentiles of the seminoma group. Tail DNA was significantly associated with nonseminoma compared to seminoma (OR{sub 50th percentile} = 3.31, 95%CI: 1.00, 10.98; OR{sub 75th percentile} = 3.71, 95%CI: 1.04, 13.20; p for trend=0.039). OTM exhibited similar, albeit statistically non-significant, risk estimates (OR{sub 50th percentile} = 2.27, 95%CI: 0.75, 6.87; OR{sub 75th percentile} = 2.40, 95%CI: 0.75, 7.71; p for trend=0.12) whereas tail length and CDM showed no association. In conclusion, the results for tail DNA and OTM indicate that endogenous DNA damage levels are higher in patients who develop nonseminoma compared with seminoma. This may partly explain the more aggressive biology and younger age-of-onset of this histologic subgroup compared with the relatively less aggressive, later-onset seminoma.

Cook, M B; Sigurdson, A J; Jones, I M; Thomas, C B; Graubard, B I; Korde, L; Greene, M H; McGlynn, K A

2008-01-18T23:59:59.000Z

33

DNA damage induced clusterin expression - A sensitive measure of genomic  

NLE Websites -- All DOE Office Websites (Extended Search)

damage induced clusterin expression - A sensitive measure of genomic damage induced clusterin expression - A sensitive measure of genomic instability David Boothman University of Texas Southwestern Medical Center at Dallas Abstract Secretory clusterin (sCLU) is a glycoprotein secreted from cells following exposure to genotoxic stress, and sCLU expression is elevated in many different disease states. sCLU is a pro-survival protein that acts as a molecular chaperone to remove cell debris caused by trauma to cells and tissues in vivo. sCLU expression is extremely sensitive to oxidative stress and DNA damage and can be induced by low dose ionizing radiation (LDIR), as low as 2 cGy. We previously demonstrated that sCLU was induced after LDIR by activation of the Insulin-like Growth Factor 1 Receptor (IGF-1R), and downstream stimulation of Src/MAPK/Erk-1/2 to promote binding of the Egr-1

34

Involvement of DNA polymerase beta in repairing oxidative damages induced by antitumor drug adriamycin  

SciTech Connect

Adriamycin (ADM) is a widely used antineoplastic drug. However, the increasing cellular resistance has become a serious limitation to ADM clinical application. The most important mechanism related to ADM-induced cell death is oxidative DNA damage mediated by reactive oxygen species (ROS). Base excision repair (BER) is a major pathway in the repair of DNA single strand break (SSB) and oxidized base. In this study, we firstly applied the murine embryo fibroblasts wild-type (pol {beta} +/+) and homozygous pol {beta} null cell (pol {beta} -/-) as a model to investigate ADM DNA-damaging effects and the molecular basis underlying these effects. Here, cellular sensitivity to ADM was examined using colorimetric assay and colony forming assay. ADM-induced cellular ROS level and the alteration of superoxide dismutase (SOD) activity were measured by commercial kits. Further, DNA strand break, chromosomal damage and gene mutation were assessed by comet assay, micronucleus test and hprt gene mutation assay, respectively. The results showed that pol {beta} -/- cells were more sensitive to ADM compared with pol {beta} +/+ cells and more severe SSB and chromosomal damage as well as higher hprt gene mutation frequency were observed in pol {beta} -/- cells. ROS level in pol {beta} -/- cells increased along with decreased activity of SOD. These results demonstrated that pol {beta} deficiency could enable ROS accumulation with SOD activity decrease, further elevate oxidative DNA damage, and subsequently result in SSB, chromosome cleavage as well as gene mutation, which may be partly responsible for the cytotoxicity of ADM and the hypersensitivity of pol {beta} -/- cells to ADM. These findings suggested that pol {beta} is vital for repairing oxidative damage induced by ADM.

Liu Shukun; Wu Mei [Department of Environmental Health, Sichuan University, West China School of Public Health, Chengdu (China); Zhang Zunzhen, E-mail: zhangzunzhen@163.co [Department of Environmental Health, Sichuan University, West China School of Public Health, Chengdu (China)

2010-08-01T23:59:59.000Z

35

DNA repair in cells sensitive and resistant to cis-diamminedichloroplatinum(II): Host cell reactivation of damaged plasmid DNA  

SciTech Connect

cis-Diamminedichloroplatinum(II) (cis-DDP) has a broad clinical application as an effective anticancer drug. However, development of resistance to the cytotoxic effects is a limiting factor. In an attempt to understand the mechanism of resistance, the authors have employed a host cell reactivation assay of DNA repair using a cis-DDP-damaged plasmid vector. The efficiency of DNA repair was assayed by measuring the activity of an enzyme coded for by the plasmid vector. The plasmid expression vector pRSV cat contains the bacterial gene coding for chloramphenicol acetyltransferase (CAT) in a configuration which permits expression in mammalian cells. The plasmid was transfected into repair-proficient and -deficient Chinese hamster ovary cells, and CAT activity was subsequently measured in cell lysates. In the repair-deficient cells, one cis-DDP adduct per cat gene was sufficient to eliminate expression. An equivalent inhibition of CAT expression in the repair-proficient cells did not occur until about 8 times the amount of damage was introduced into the plasmid. These results implicate DNA intrastrand cross-links as the lesions responsible for the inhibition of CAT expression. This assay was used to investigate the potential role of DNA repair in mediating cis-DDP resistance in murine leukemia L1210 cells. The assay readily detects the presence or absence of repair and confirms that these resistant L1210 cells have an enhanced capacity for repair of cis-DDP-induced intrastrand cross-links.

Sheibani, N.; Jennerwein, M.M.; Eastman, A. (Univ. of Nebraska Medical Center, Omaha (USA))

1989-04-04T23:59:59.000Z

36

DNA damage produced by exposure of supercoiled plasmid DNA to high- and low-LET ionizing radiation: Effects of hydroxyl radical quenchers. DNA breakage, neutrons, OH radicals  

SciTech Connect

A supercoiled plasmid of 7300 base pairs was isolated and exposed in an aqueous environment to {sup 60}Co {gamma} rays and JANUS 0.85 MeV fission-spectrum neutrons. Dose responses for the production of single-strand breaks (SSBs), double-strand breaks (DSBs) and alkali-labile sites (ALSs) were compared with computations made from the conversion of the supercoil to its relaxed and linear forms. The relative biological effectiveness (RBE) for production of SSBs and DSBs was similar to that previously measured in the cellular environment. The RBE for destruction of genetic transforming activity of M13 viral DNA followed that for DNA damage. This is in contrast to the situation for biological effects such as lethality, mutagenesis, and cellular transformation measured in mammalian cells, where the RBE values are reversed. The role of hydroxyl (OH) radical in DNA damage induction by neutrons was investigated by exposure of plasmid in the presence of known quenchers of this species. Of four quenchers tested, all were able to reduce the yields of both SSBs and DSBs. These findings are consistent with a model for SSB and DSB induction by high linear energy transfer that involves OH radical mediation.

Peak, J.G.; Ito, T.; Peak, M.J. [Argonne National Lab., IL (United States); Robb, F.T. [Univ. of Maryland, Baltimore, MD (United States). Center for Marine Biotechnology

1994-08-01T23:59:59.000Z

37

{beta}-carboline derivatives: Novel photosensitizers that intercalate into DNA to cause direct DNA damage in photodynamic therapy  

SciTech Connect

Novel 1,3,9-trisubstituted {beta}-carboline derivatives were found to exhibit DNA photocleavage properties under visible light irradiation in a cell-free system, which could be reduced by antioxidant vitamin E. Their photo-cytotoxicity to human tumor cell line HeLa was confirmed, in which apoptosis only contributed a small part to the cell death, and necrosis was the dominating outcome of HeLa cells in photodynamic therapy (PDT) using {beta}-carboline derivatives. Different from other clinical PDT drugs, {beta}-carboline derivatives were demonstrated to be able to distribute in the nucleus and intercalate into DNA, and consequently cause direct DNA damage by photochemical reaction products in PDT, which was proved by the distinct DNA tails in the comet assay and the considerable amount of DNA damaged cells quantified by flow cytometry. This mechanism could be the explanation for the delay of cell proliferation at DNA synthesis and mitosis.

Guan Huaji [State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Therapeutic Functional Genes, Department of Biochemistry, College of Life Sciences, Sun Yat-sen (Zhongshan) University, 135 Xin Gang Xi Road, Guangzhou 510275 (China); Liu Xiaodong [State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Therapeutic Functional Genes, Department of Biochemistry, College of Life Sciences, Sun Yat-sen (Zhongshan) University, 135 Xin Gang Xi Road, Guangzhou 510275 (China); Peng Wenlie [State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Therapeutic Functional Genes, Department of Biochemistry, College of Life Sciences, Sun Yat-sen (Zhongshan) University, 135 Xin Gang Xi Road, Guangzhou 510275 (China); Cao Rihui [State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Therapeutic Functional Genes, Department of Biochemistry, College of Life Sciences, Sun Yat-sen (Zhongshan) University, 135 Xin Gang Xi Road, Guangzhou 510275 (China); Ma Yan [State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Therapeutic Functional Genes, Department of Biochemistry, College of Life Sciences, Sun Yat-sen (Zhongshan) University, 135 Xin Gang Xi Road, Guangzhou 510275 (China); Chen Hongsheng [State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Therapeutic Functional Genes, Department of Biochemistry, College of Life Sciences, Sun Yat-sen (Zhongshan) University, 135 Xin Gang Xi Road, Guangzhou 510275 (China); Xu Anlong [State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Therapeutic Functional Genes, Department of Biochemistry, College of Life Sciences, Sun Yat-sen (Zhongshan) University, 135 Xin Gang Xi Road, Guangzhou 510275 (China)]. E-mail: ls36@zsu.edu.cn

2006-04-14T23:59:59.000Z

38

Live Cell Imaging and in situ analysis of cellular responses to DNA doublestrand  

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Live Cell Imaging and in situ analysis of cellular responses to DNA double- Live Cell Imaging and in situ analysis of cellular responses to DNA double- strand breaks in mammalian cells. David J. Chen Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas TX 75390 The integrity of the human genome is constantly threatened by internal as well as external factors with the propensity to cause DNA damage. Of the various types of DNA damage that can occur within the mammalian cell nucleus, the DNA double strand break (DSB) is perhaps the most dangerous. Estimates put the number of endogenous DSBs anywhere between 10-100 per nucleus per day. A direct link between DSBs and cancer has been surmised by researchers based upon the fact that many cancer-predisposition

39

International congress on DNA damage and repair: Book of abstracts  

SciTech Connect

This document contains the abstracts of 105 papers presented at the Congress. Topics covered include the Escherichia coli nucleotide excision repair system, DNA repair in malignant transformations, defective DNA repair, and gene regulation. (TEM)

Not Available

1987-01-01T23:59:59.000Z

40

Mechanistic investigation of an anticancer agent that damages DNA and interacts with the androgen receptor  

E-Print Network (OSTI)

The 11[beta] molecule comprises a ligand for the androgen receptor (AR), which is crucial to progression and survival of many prostate cancers, tethered to a DNA-damaging aniline mustard. The compound was designed to exhibit ...

Proffitt, Kyle David

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "dna damage response" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

The role of ClpXP-mediated proteolysis in resculpting the proteome after DNA damage  

E-Print Network (OSTI)

When faced with environmental assaults, E. coli can take extreme measures to survive. For example, starving bacteria consume their own proteins, and bacteria with severe DNA damage introduce mutations into their genomes. ...

Neher, Saskia B. (Saskia Byerly)

2005-01-01T23:59:59.000Z

42

Low Dose Radiation Research Program: Comparison of DNA Damage Risk from  

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Comparison of DNA Damage Risk from Low-Dose Radiation and Folate Comparison of DNA Damage Risk from Low-Dose Radiation and Folate Deficiency. Authors: Chantal Courtemanche, Arnold C. Huang, Nicole Kerry, Bernice Ng, and Bruce N. Ames. Institutions: Children’s Hospital Oakland Research Institute, Oakland, California. Our overall goal is to understand and quantify the real effects of low-dose radiation by measuring direct and specific cellular changes. However, since the background dose of radiation to which most individuals are exposed is well below the levels where significant biological effects, such as mutation or tumor induction, are observed, our novel approach is to compare the consequences of radiation to those of specific nutritional deficiencies. By determining which of these two common stresses at physiologically relevant doses leads to a greater amount of DNA damage, we

43

Histone H2AX participates the DNA damage-induced ATM activation through interaction with NBS1  

SciTech Connect

Phosphorylated histone H2AX ({gamma}-H2AX) functions in the recruitment of DNA damage response proteins to DNA double-strand breaks (DSBs) and facilitates DSB repair. ATM also co-localizes with {gamma}-H2AX at DSB sites following its auto-phosphorylation. However, it is unclear whether {gamma}-H2AX has a role in activation of ATM-dependent cell cycle checkpoints. Here, we show that ATM as well as NBS1 is recruited to damaged-chromatin in a {gamma}-H2AX-dependent manner. Foci formation of phosphorylated ATM and ATM-dependent phosphorylation is repressed in H2AX-knockdown cells. Furthermore, anti-{gamma}-H2AX antibody co-immunoprecipitates an ATM-like protein kinase activity in vitro and recombinant H2AX increases in vitro kinase activity of ATM from un-irradiated cells. Moreover, H2AX-deficient cells exhibited a defect in ATM-dependent cell cycle checkpoints. Taken together, {gamma}-H2AX has important role for effective DSB-dependent activation of ATM-related damage responses via NBS1.

Kobayashi, Junya [Department of Genome Repair Dynamics, Radiation Biology Center, Kyoto University, Kyoto 606-8501 (Japan)], E-mail: jkobayashi@house.rbc.kyoto-u.ac.jp; Tauchi, Hiroshi [Department of Environmental Sciences, Ibaraki University, Ibaraki 310-8512 (Japan); Chen, Benjamin; Bruma, Sandeep [Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas, Southwestern Medical Center at Dallas, Dallas, TX 75390-9187 (United States); Tashiro, Satoshi [Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8553 (Japan); Matsuura, Shinya [Department of Radiation Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8553 (Japan); Tanimoto, Keiji [Department of Oral and Maxillofacial Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553 (Japan); Chen, David J. [Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas, Southwestern Medical Center at Dallas, Dallas, TX 75390-9187 (United States); Komatsu, Kenshi [Department of Genome Repair Dynamics, Radiation Biology Center, Kyoto University, Kyoto 606-8501 (Japan)], E-mail: komatsu@house.rbc.kyoto-u.ac.jp

2009-03-20T23:59:59.000Z

44

Understanding cell fate decisions in response to 0?-Methylguanine DNA lesions  

E-Print Network (OSTI)

The stability of the genome is constantly challenged by both endogenous and exogenous DNA damaging agents. DNA damage, if left unrepaired, can give rise to permanent genetic alterations that ultimately increase our risk ...

Noonan, Ericka Marie

2011-01-01T23:59:59.000Z

45

A molecular dynamics simulation of DNA damage induction by ionizing radiation  

E-Print Network (OSTI)

We present a multi-scale simulation of early stage of DNA damages by the indirect action of hydroxyl ($^\\bullet$OH) free radicals generated by electrons and protons. The computational method comprises of interfacing the Geant4-DNA Monte Carlo with the ReaxFF molecular dynamics software. A clustering method was employed to map the coordinates of $^\\bullet$OH-radicals extracted from the ionization track-structures onto nano-meter simulation voxels filled with DNA and water molecules. The molecular dynamics simulation provides the time evolution and chemical reactions in individual simulation voxels as well as the energy-landscape accounted for the DNA-$^\\bullet$OH chemical reaction that is essential for the first principle enumeration of hydrogen abstractions, chemical bond breaks, and DNA-lesions induced by collection of ions in clusters less than the critical dimension which is approximately 2-3 \\AA. We show that the formation of broken bonds leads to DNA base and backbone damages that collectively propagate ...

Abolfath, Ramin M; Chen, Zhe J; Nath, Ravinder

2013-01-01T23:59:59.000Z

46

Low energy electron induced damage to plasmid DNA pQE30  

SciTech Connect

Low energy electrons (LEEs) are produced in copious amounts by the primary radiation used in radiation therapy. The damage caused to the DNA by these secondary electrons in the energy range 5-22 eV has been studied to understand their possible role in radiation induced damage. Electrons are irradiated on dried films of plasmid DNA (pQE30) and analysed using agarose gel electrophoresis. Single strand breaks (SSBs) induced by LEE to supercoiled plasmid DNA show resonance structures at 7, 12, and 15 eV for low doses and 6, 10, and {approx}18 eV at saturation doses. The present measurements have an overall agreement with the literature that LEEs resonantly induce SSBs in DNA. Resonant peaks in the SSBs induced by LEEs at 7, 12, and 15 eV with the lowest employed dose in the current study are somewhat different from those reported earlier by two groups. The observed differences are perhaps related to the irradiation dose, conditions and the nature of DNA employed, which is further elaborated.

Kumar, S. V. K.; Pota, Tasneem; Peri, Dinakar; Dongre, Anushka D.; Rao, Basuthkar J. [Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005 (India)

2012-07-28T23:59:59.000Z

47

Repair of UV damaged DNA, genes and proteins of yeast and human  

Science Conference Proceedings (OSTI)

Our objectives are to determine the molecular mechanism of the incision step of excision repair of ultraviolet (UV) light damaged DNA in eukaryotic organisms, using the yeast Saccharomyces cerevisiae as a model system, as well as studying the human homologs of yeast excision repair and postreplication repair proteins. In addition to its single-stranded DNA-dependent A TPase and DNA helicase activities, we have found that RAD3 protein also possesses DNA-RNA helicase activity, and that like RAD3, the Schizosaccharomyces pombe RAD3 homolog, rhp3{sup +}, is an essential gene. We have overexpressed the human RAD3 homolog, ERCC2, in yeast to facilitate its purification. The RAD10 protein was purified to homogeneity and shown to bind DNA. ERCC3y, the yeast homolog of the human ERCC-3/XP-B gene, has been sequenced and shown to be essential for viability. The Drosophila and human homologs of RAD6, required for postreplication repair and UV induced mutagenesis, were shown to complement the rad6 {Delta} mutation of yeast. Since defective DNA repair and enhanced neoplasia characterize several human genetic diseases, and repair proteins are highly conserved between yeast and man, a thorough understanding of the molecular mechanisms of DNA repir in yeast should provide a better understanding of the causes of carcinogenesis.

Prakash, L.

1991-04-01T23:59:59.000Z

48

Low Dose Radiation Research Program: DNA Damage in Acutely Irradiated F2  

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DNA Damage in Acutely Irradiated F2 Mice with a History of Paternal DNA Damage in Acutely Irradiated F2 Mice with a History of Paternal F0 Germline Irradiation Authors: J.E. Baulch and O.G. Raabe Institutions: Center for Health and the Environment, University of California, Davis, CA. The main goal of this grant is to evaluate heritable, transgenerational effects of low dose, low-linear-energy-transfer (LET) radiation (0.1 Gy attenuated 137Cs gamma rays) on Type B spermatogonia in 129SVE mice; wild-type and heterozygous for Ataxia-telangiectasia (AT). The ATM heterozygotes are carriers for a genetic mutation (AT mutated, ATM) that is thought to predispose both humans and mice to radiation sensitivity. Experiments conducted in our laboratory have demonstrated heritable effects of paternal germline exposure to ionizing radiation in mice using 1.0 Gy of

49

Job Title: 2 PhD positions, Marie Curie Initial Training Network (ITN) on Chronic DNA Damage in Ageing Reference: EMBO Young Investigator PHD position  

E-Print Network (OSTI)

Job Title: 2 PhD positions, Marie Curie Initial Training Network (ITN) on Chronic DNA DamageD candidates will be part of a Marie Curie Initial Training Network (ITN) that aims to implement an integrated defects in genome maintenance thus pointing towards damage in (nuclear) DNA as a major culprit of ageing

50

DNA Repair Biomarkers Predict Response to Neoadjuvant Chemoradiotherapy in Esophageal Cancer  

SciTech Connect

Purpose: The addition of neoadjuvant chemoradiotherapy prior to surgical resection for esophageal cancer has improved clinical outcomes in some trials. Pathologic complete response (pCR) following neoadjuvant therapy is associated with better clinical outcome in these patients, but only 22% to 40% of patients achieve pCR. Because both chemotherapy and radiotherapy act by inducing DNA damage, we analyzed proteins selected from multiple DNA repair pathways, using quantitative immunohistochemistry coupled with a digital pathology platform, as possible biomarkers of treatment response and clinical outcome. Methods and Materials: We identified 79 patients diagnosed with esophageal cancer between October 1994 and September 2002, with biopsy tissue available, who underwent neoadjuvant chemoradiotherapy prior to surgery at the Massachusetts General Hospital and used their archived, formalin-fixed, paraffin-embedded biopsy samples to create tissue microarrays (TMA). TMA sections were stained using antibodies against proteins in various DNA repair pathways including XPF, FANCD2, PAR, MLH1, PARP1, and phosphorylated MAPKAP kinase 2 (pMK2). Stained TMA slides were evaluated using machine-based image analysis, and scoring incorporated both the intensity and the quantity of positive tumor nuclei. Biomarker scores and clinical data were assessed for correlations with clinical outcome. Results: Higher scores for MLH1 (p = 0.018) and lower scores for FANCD2 (p = 0.037) were associated with pathologic response to neoadjuvant chemoradiation on multivariable analysis. Staining of MLH1, PARP1, XPF, and PAR was associated with recurrence-free survival, and staining of PARP1 and FANCD2 was associated with overall survival on multivariable analysis. Conclusions: DNA repair proteins analyzed by immunohistochemistry may be useful as predictive markers for response to neoadjuvant chemoradiotherapy in patients with esophageal cancer. These results are hypothesis generating and need confirmation in an independent data set.

Alexander, Brian M., E-mail: bmalexander@lroc.harvard.edu [Department of Radiation Oncology, Dana-Farber/Brigham and Women's Cancer Center, Boston, Massachusetts (United States); Wang Xiaozhe [On-Q-ity, Inc., Waltham, Massachusetts (United States); Niemierko, Andrzej [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Weaver, David T. [On-Q-ity, Inc., Waltham, Massachusetts (United States); Mak, Raymond H. [Department of Radiation Oncology, Dana-Farber/Brigham and Women's Cancer Center, Boston, Massachusetts (United States); Roof, Kevin S. [Southeast Radiation Oncology, Charlotte, North Carolina (United States); Fidias, Panagiotis [Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts (United States); Wain, John [Department of Surgery, Massachusetts General Hospital, Boston, Massachusetts (United States); Choi, Noah C. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States)

2012-05-01T23:59:59.000Z

51

Workshop on the Application of Remote Sensing Technologies to Disaster Response Rapid Damage Mapping for Post-Earthquake  

E-Print Network (OSTI)

Workshop on the Application of Remote Sensing Technologies to Disaster Response Rapid Damage Technologies to Disaster Response September 12 2003 #12;Workshop on the Application of Remote Sensing Technologies to Disaster Response 12 September 2003 Rapid Damage Mapping for post-Earthquake Building Damage

Shinozuka, Masanobu

52

Earthquake Induced Damage Mechanism of Long Period Structures Using Energy Response  

SciTech Connect

This paper presents a method of expounding the damage of RC long period frame structure using energy analysis method. Since the damage of structures usually occurs under major earthquakes, the structure is assumed to be in elasto-plastic state, and degraded Bouc-Wen model is used to describe the hysteretic component of the restoring force. A double index damage criterion defined by the maximum drift and energy absorption is used as the damage criterion. The energy transferring relation in a structure is derived, and both momentary and cumulative energy response is used to reflect the delay of the collapse of a long period structure. The mechanism of collapse delay of the long period structure is suggested through a numerical example combing the energy response and time history response.

Du Yongfeng; Li Hui [Western Engineering Research Center for Disaster Mitigation in Civil Engineering of Ministry of Education, Lanzhou, 730050 (China); Institute of Earthquake Protection and Disaster Mitigation, Lanzhou University of Technology, Lanzhou, 730050 (China)

2008-07-08T23:59:59.000Z

53

The low dose damage response pathways in the mouse mammary glands depends  

NLE Websites -- All DOE Office Websites (Extended Search)

low dose damage response pathways in the mouse mammary glands depends low dose damage response pathways in the mouse mammary glands depends on genotype, tissue compartment, exposure regimen, and sampling times Joe Gray & Andrew Wyrobek Lawrence Berkeley National Laboratory Abstract The objectives of this research are to characterize the early and persistent low-dose and adaptive response (AR) damage surveillance networks in mammary glands of radiation sensitive and resistant strains of mice to identify the molecular signatures/mechanisms associated with nonlinear modifications of risk for mammary gland cancer. Our approach uses low-dose exposure regimens that have been reported to induce mammary gland cancer in sensitive strains to determine whether low-dose induced pathways are differentially expressed in epithelial or stromal cells and to determine

54

Spin-blockade effect and coherent control of DNA-damage by free radicals: a proposal on bio-spintronics  

E-Print Network (OSTI)

Coherent control of OH-free radicals interacting with the spin-triplet state of a DNA molecule is investigated. A model Hamiltonian for molecular spin singlet-triplet resonance is developed. We illustrate that the spin-triplet state in DNA molecules can be efficiently populated, as the spin-injection rate can be tuned to be orders of magnitudes greater than the decay rate due to small spin-orbit coupling in organic molecules. Owing to the nano-second life-time of OH free radicals, a non-equilibrium free energy barrier induced by the injected spin triplet state that lasts approximately longer than one-micro second in room temperature can efficiently block the initial Hydrogen abstraction and DNA damage. For a direct demonstration of the spin-blockade effect, a molecular simulation based on an {\\em ab-initio} Car-Parrinello molecular dynamics is deployed.

Abolfath, Ramin M

2011-01-01T23:59:59.000Z

55

Reactive oxygen species and oxidative DNA damage mediate the cytotoxicity of tungsten-nickel-cobalt alloys in vitro  

Science Conference Proceedings (OSTI)

Tungsten alloys (WA) have been introduced in an attempt to find safer alternatives to depleted uranium and lead munitions. However, it is known that at least one alloy, 91% tungsten-6% nickel-3% cobalt (WNC-91-6-3), causes rhabdomyosarcomas when fragments are implanted in rat muscle. This raises concerns that shrapnel, if not surgically removable, may result in similar tumours in humans. There is therefore a clear need to develop rapid and robust in vitro methods to characterise the toxicity of different WAs in order to identify those that are most likely to be harmful to human health and to guide development of new materials in the future. In the current study we have developed a rapid visual in vitro assay to detect toxicity mediated by individual WA particles in cultured L6-C11 rat muscle cells. Using a variety of techniques (histology, comet assay, caspase-3 activity, oxidation of 2'7'-dichlorofluorescin to measure the production of reactive oxygen species and whole-genome microarrays) we show that, in agreement with the in vivo rat carcinogenicity studies, WNC-91-6-3 was the most toxic of the alloys tested. On dissolution, it produces large amounts of reactive oxygen species, causes significant amounts of DNA damage, inhibits caspase-3, triggers a severe hypoxic response and kills the cells in the immediate vicinity of the alloy particles within 24 h. By combining these in vitro data we offer a mechanistic explanation of the effect of this alloy in vivo and show that in vitro tests are a viable alternative for assessing new alloys in the future.

Harris, R.M.; Williams, T.D.; Hodges, N.J.; Waring, R.H., E-mail: R.H.Waring@bham.ac.uk

2011-01-01T23:59:59.000Z

56

A Critical Examination of the Adaptive Response for Cytogenetic Damage in  

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Critical Examination of the Adaptive Response for Cytogenetic Damage in Critical Examination of the Adaptive Response for Cytogenetic Damage in Human Cells, and Insights into the Adaptive Response Mechanism Björn E. Rydberg Lawrence Berkeley National Laboratory Abstract Goal: Task 1 of the Berkeley Lab SFA is designed to identify adaptive response (AR) mechanisms that may affect risk of developing radiation-induced cancer and to assess the linearity with dose of processes that influence mammary gland carcinogenesis. We use both in vitro and in vivo experimental systems in a parallelogram strategy. Our human cell culture model will elucidate the molecular mechanisms of the AR and investigate the relationships in target vs. non-target cells between a range of cancer-relevant endpoints potentially affected by adaptation such

57

Mechanisms Underlying Cellular Responses to Low Dose/Low LET...  

NLE Websites -- All DOE Office Websites (Extended Search)

expression, chromosomal and apoptotic analysis suggest a model for strain specific radiation response; normal DNA damage recognition and repair leading to cell death and...

58

Low Dose Radiation Research Program: Assessing Biological Function of DNA  

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Assessing Biological Function of DNA Damage Response Genes Assessing Biological Function of DNA Damage Response Genes Larry H. Thompson Lawrence Livermore National Laboratory Why This Project To understand the relative importance of individual DNA repair and DNA-damage response pathways to the recovery of mammalian cells after exposure to low doses of ionizing radiation (IR). This understanding may lead to better ways of setting limits on human exposure to IR. In spite of the discovery of many mammalian DNA repair genes, our current knowledge of how many of these genes contribute to cellular recovery from IR exposure is quite limited. Project Goals Measure cellular responses at doses in the 5-100 cGy range, which generally cause changes too small to detect in normal, repair-proficient cells Focus on DNA double-strand breaks (DSBs) and DNA oxidative base

59

P450 aromatase alterations and DNA damage as avian pollution biomarkers in cliff and cave swallow breeding near the Rio Grande region, Texas  

E-Print Network (OSTI)

The endocrine system, specifically relating to sex hormones, and genetic material can be targets of environmental contaminants. Environmental contaminants in the Rio Grande region may originate from industrial or agricultural processes and growing populations lacking proper water and sewage infrastructure. Cliff (Petrochelidon pyrrhonota) and cave (P. fulva) swallows breeding near the Rio Grande were selected to monitor aromatase activity alterations and DNA damage. Swallows were sampled at six sites along the Rio Grande from Brownsville to Laredo, and a reference site (Somerville) 350 miles north of the Rio Grande. DNA damage, based on nuclear DNA content, was determined by flow cytometry. A significantly larger mean half peak coefficient of variation (HPCV) of DNA content in contaminated sites compared to a reference site reflects possible chromosomal damage. No detectable HPCV differences were observed in cave swallows among locations, notwithstanding the presence of mutagenic contaminants. Selenium may provide a protective role against genetic damage. However, cliff swallows from Laredo had significantly higher HPCV values than those from Somerville. DNA damage could be attributed to metals and polycyclic aromatic hydrocarbons released near Laredo. Brains and gonads, two estrogen-dependent organs, were tested for aromatase activity with a tritiated water method. Brain aromatase activity was higher, though not always statistically, for male cave and male and female cliff swallows. Dichlorodiphenyldichloroethylene (DDE) may play a role in the increased activity. Female cave swallows in Llano Grande appeared to have a greatly depressed brain aromatase activity, possibly attributed to past human use of toxaphene. Testicular and ovarian aromatase activity in cliff and cave swallows from Rio Grande was higher than in those from Somerville, though not always significantly. DDE, atrazine, sewage treatment plant contaminants (phthalates, alkylphenols, ethynylestradiol), metals, or other pollutants could play a role in the increased gonadal activity. Increased aromatase activity, in association with contaminants, may be easier to detect in testes of male birds which normally exhibit low levels of estrogen. Siterelated contaminants may be playing a role in DNA damage and aromatase alterations. This is the first known study which uses aromatase activity as an endocrine disruptor indicator in wild birds.

Sitzlar, Megan Annette

2005-12-01T23:59:59.000Z

60

The Role of DNA double-strand break repair in cellular response to low  

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DNA double-strand break repair in cellular response to low DNA double-strand break repair in cellular response to low dose radiation exposure. David J. Chen Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas TX 75390 It has been assumed that molecular pathways that involved in the biological response for low dose of radiation should be similar to those for high dose radiation in general. The low dose-rate effect and DNA double-strand break repair are inextricably linked in mammalian cells. It has been reported that mammalian mutant cells deficient in nonhomologous end join (NHEJ) pathway have little or no cellular recovery when expose to low-dose-rate radiation. Recently, it has also been reported that cells deficient in

Note: This page contains sample records for the topic "dna damage response" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

EHS0749 PI rDNA Responsibilities Syllabus Form 01=03=13  

NLE Websites -- All DOE Office Websites (Extended Search)

EHS 749 ~ PI Recombinant DNA (rDNA) Responsibilities Course Syllabus Subject Category: Biosafety Course Prerequisite: None Course Length: 10 minutes Medical Approval: None Delivery Mode: Online Schedule: Available online Location/Time: N/A Course Purpose: Ensure that principle investigators (PIs) of non-exempt recombinant research are aware of their responsibilities and expectations under the NIH Guidelines Course Objectives: Awareness of the following: * NIH Guidelines for Research Involving Recombinant or Synthetic Nucleic Acid Molecules * LBNL and non-exempt rDNA experiments are subject to the NIH Guidelines * Biosafety Manual and Biosafety Work Authorizations contain NIH and other biosafety requirements * NIH Office of Biotechnology Activities (OBA) is the agency that oversees the NIH Guidelines

62

Insulin signaling, dietary restriction and DNA damage : multiple roles for smk-1 in the mediation of C. elegans life span  

E-Print Network (OSTI)

Chem 276, 41553-41558. Shackelford, D.A. (2006). DNA enddisease in neuronal cells (Shackelford, 2006; Vyjayanti and

Wolff, Suzanne Christine

2008-01-01T23:59:59.000Z

63

A CRTC2 Repressor Role Regulates DNA Damage Response Genes in Germinal Center B-cells  

E-Print Network (OSTI)

Welman, A. Comparison of doxycycline delivery methods for1994). Kistner, A. et al. Doxycycline-mediated quantitativeaddition of the drug doxycycline or tetracycline. It is

Schontzler, Olivia Tersa

2012-01-01T23:59:59.000Z

64

Damage to DNA thymine residues in CHO cells by hydrogen peroxide and copper, ascorbate and copper, hypochlorite, or other oxidants: Protection by low MW polyethylene glycol  

SciTech Connect

Polyethylene glycol (PEG) MW 200-600, has been shown to protect animals against oxidant and radiation damage. In order to study the mechanism the authors examined the effect of PEG on damage to thymine residues in the DNA of living Chinese hamster ovary (CHO) cells. After growing to confluence in the presence of (methyl{sup 3}H)thymidine, the cells were treated, usually for 1 hr, with various combinations of H{sub 2}O{sub 2}, Cu{sup ++}, Fe{sup ++}, Ocl{sup {minus}}, ascorbate UV or X-irradiation, and PEG MW 300. The oxidants H{sub 2}O{sub 2}/Cu{sup ++}, and OCL{sup {minus}} released {sup 3}H into the medium from DNA thymine, and also formed thymine glycol residues in the DNA that were assayed by alkaline borohydride. The presence of 10% PEG during treatment significantly reduced the release of {sup 3}H into the medium but did not prevent formation of thymine glycol residues bound to the DNA. PEG at 10% had no effect on the cloning efficiency of CHO cells.

Schellenberg, K.A.; Shaeffer, J. (Eastern Virginia Medical School, Norfolk (United States))

1991-03-11T23:59:59.000Z

65

Nbs1-dependent binding of Mre11 to adenovirus E4 mutant viral DNA is important for inhibiting DNA replication  

Science Conference Proceedings (OSTI)

Adenovirus (Ad) infections stimulate the activation of cellular DNA damage response and repair pathways. Ad early regulatory proteins prevent activation of DNA damage responses by targeting the MRN complex, composed of the Mre11, Rad50 and Nbs1 proteins, for relocalization and degradation. In the absence of these viral proteins, Mre11 colocalizes with viral DNA replication foci. Mre11 foci formation at DNA damage induced by ionizing radiation depends on the Nbs1 component of the MRN complex and is stabilized by the mediator of DNA damage checkpoint protein 1 (Mdc1). We find that Nbs1 is required for Mre11 localization at DNA replication foci in Ad E4 mutant infections. Mre11 is important for Mdc1 foci formation in infected cells, consistent with its role as a sensor of DNA damage. Chromatin immunoprecipitation assays indicate that both Mre11 and Mdc1 are physically bound to viral DNA, which could account for their localization in viral DNA containing foci. Efficient binding of Mre11 to E4 mutant DNA depends on the presence of Nbs1, and is correlated with a significant E4 mutant DNA replication defect. Our results are consistent with a model in which physical interaction of Mre11 with viral DNA is mediated by Nbs1, and interferes with viral DNA replication.

Mathew, Shomita S. [Department of Microbiology, 32 Pearson Hall, Miami University, Oxford OH 45056 (United States); Bridge, Eileen [Department of Microbiology, 32 Pearson Hall, Miami University, Oxford OH 45056 (United States)], E-mail: BridgeE@muohio.edu

2008-04-25T23:59:59.000Z

66

DNA  

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directed directed assembly of nanoparticle linear structure for nanophotonics Baoquan Ding, a͒ Stefano Cabrini, b͒ Ronald N. Zuckermann, and Jeffrey Bokor Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, California 94720 ͑Received 17 June 2008; accepted 22 December 2008; published 2 February 2009͒ Assemblies of metal nanospheres have shown interesting properties for nanophotonics. Here the authors describe a method to use robust DNA multicrossover molecules to organize Au nanoparticles with different sizes to form well controlled linear chain structures with desired distance below 10 nm between the particles. Au particles with only one piece of DNA attached are purified individually. Three different sizes DNA-Au conjugates then hybridize with five other DNA strands to form the stiff triple crossover ͑TX͒ motif. The linkage position

67

Modulating radiation induced TGFB and ATM signaling in the DNA...  

NLE Websites -- All DOE Office Websites (Extended Search)

TGF and ATM signaling in the DNA damage response Jennifer A. Anderson 1 , Francis A. Cucinotta 2 and Peter O'Neill 1 1 Gray Institute for Radiation Oncology and Biology,...

68

Modeling of Damage, Permeability Changes and Pressure Responses during Excavation of the TSX Tunnel in Granitic Rock at URL, Canada  

SciTech Connect

This paper presents numerical modeling of excavation-induced damage, permeability changes, and fluid-pressure responses during excavation of the TSX tunnel at the underground research laboratory (URL) in Canada. Four different numerical models were applied, using a wide range of approaches to model damage and permeability changes in the excavation disturbed zone (EDZ) around the tunnel. Using in situ calibration of model parameters the modeling could reproduce observed spatial distribution of damage and permeability changes around the tunnel, as a combination of disturbance induced by stress redistribution around the tunnel and by the drill-and-blast operation. The modeling showed that stress-induced permeability increase above the tunnel is a result of micro and macrofracturing under high deviatoric (shear) stress, whereas permeability increases alongside the tunnel as a result of opening of existing microfractures under decreased mean stress. The remaining observed fracturing and permeability changes around the periphery of the tunnel were attributed to damage from the drill-and-blast operation. Moreover, a reasonably good agreement was achieved between simulated and observed excavation-induced pressure responses around the TSX tunnel for 1 year following its excavation. The simulations showed that these pressure responses are caused by poroelastic effects as a result of increasing or decreasing mean stress, with corresponding contraction or expansion of the pore volume. The simulation results for pressure evolution were consistent with previous studies, indicating that the observed pressure responses could be captured in a Biot model using a relatively low Biot-Willis coefficient, {alpha} {approx} 0.2, a porosity of n {approx} 0.007, and a relatively low permeability of k {approx} 2 x 10{sup -22} m{sup 2}, which is consistent with the very tight, unfractured granite at the site.

Rutqvist, Jonny; Borgesson, Lennart; Chijimatsu, Masakazu; Hernelind, Jan; Jing, Lanru; Kobayashi, Akira; Nguyen, Son

2008-08-01T23:59:59.000Z

69

Role of Cell Cycle Regulation and MLH1, A Key DNA Mismatch Repair Protein, In Adaptive Survival Responses. Final Report  

SciTech Connect

Due to several interesting findings on both adaptive survival responses (ASRs) and DNA mismatch repair (MMR), this grant was separated into two discrete Specific Aim sets (each with their own discrete hypotheses). The described experiments were simultaneously performed.

David A. Boothman

1999-08-11T23:59:59.000Z

70

DNA-based Self-Assembly of Chiral Plasmonic Nanostructures with Tailored Optical Response  

E-Print Network (OSTI)

Surface plasmon resonances generated in metallic nanostructures can be utilized to tailor electromagnetic fields. The precise spatial arrangement of such structures can result in surprising optical properties that are not found in any naturally occurring material. Here, the designed activity emerges from collective effects of singular components equipped with limited individual functionality. Top-down fabrication of plasmonic materials with a predesigned optical response in the visible range by conventional lithographic methods has remained challenging due to their limited resolution, the complexity of scaling, and the difficulty to extend these techniques to three-dimensional architectures. Molecular self-assembly provides an alternative route to create such materials which is not bound by the above limitations. We demonstrate how the DNA origami method can be used to produce plasmonic materials with a tailored optical response at visible wavelengths. Harnessing the assembly power of 3D DNA origami, we arranged metal nanoparticles with a spatial accuracy of 2 nm into nanoscale helices. The helical structures assemble in solution in a massively parallel fashion and with near quantitative yields. As a designed optical response, we generated giant circular dichroism and optical rotary dispersion in the visible range that originates from the collective plasmon-plasmon interactions within the nanohelices. We also show that the optical response can be tuned through the visible spectrum by changing the composition of the metal nanoparticles. The observed effects are independent of the direction of the incident light and can be switched by design between left- and right-handed orientation. Our work demonstrates the production of complex bulk materials from precisely designed nanoscopic assemblies and highlights the potential of DNA self-assembly for the fabrication of plasmonic nanostructures.

Anton Kuzyk; Robert Schreiber; Zhiyuan Fan; Gnther Pardatscher; Eva-Maria Roller; Alexander Hgele; Friedrich C. Simmel; Alexander O. Govorov; Tim Liedl

2011-08-18T23:59:59.000Z

71

Protein Bridges DNA Base and Nucleotide Excision Repair Pathways  

NLE Websites -- All DOE Office Websites (Extended Search)

Protein Bridges DNA Base and Protein Bridges DNA Base and Nucleotide Excision Repair Pathways Protein Bridges DNA Base and Nucleotide Excision Repair Pathways Print Wednesday, 28 October 2009 00:00 Alkyltransferase proteins (AGT) protect cells from the biological effects of DNA damage caused by the addition of alkyl groups (alkylation). Alkyltransferase-like proteins (ATLs) can do the same, but they lack the reactive cysteine residue that allows the alkyltransferase function, and the mechanism for cell protection has remained unknown. To address this mystery, a British-American team lead by researchers at the Scripps Research Institute recently applied a combination of x-ray structural, biochemical, and genetic studies to ATLs in the yeast Schizosaccharomyces pombe without and with damaged DNA. By showing how a process called non-enzymatic nucleotide flipping activates ATL-initiated DNA repair, their results may improve our understanding of genomic integrity and responses to DNA damage relevant to pathogens and cancer development.

72

Expanded breadth of the T-cell response to mosaic HIV-1 envelope DNA vaccination  

SciTech Connect

An effective AIDS vaccine must control highly diverse circulating strains of HIV-1. Among HIV -I gene products, the envelope (Env) protein contains variable as well as conserved regions. In this report, an informatic approach to the design of T-cell vaccines directed to HIV -I Env M group global sequences was tested. Synthetic Env antigens were designed to express mosaics that maximize the inclusion of common potential Tcell epitope (PTE) 9-mers and minimize the inclusion of rare epitopes likely to elicit strain-specific responses. DNA vaccines were evaluated using intracellular cytokine staining (ICS) in inbred mice with a standardized panel of highly conserved 15-mer PTE peptides. I, 2 and 3 mosaic sets were developed that increased theoretical epitope coverage. The breadth and magnitude ofT-cell immunity stimulated by these vaccines were compared to natural strain Env's; additional comparisons were performed on mutant Env's, including gpl60 or gpl45 with or without V regions and gp41 deletions. Among them, the 2 or 3 mosaic Env sets elicited the optimal CD4 and CD8 responses. These responses were most evident in CD8 T cells; the 3 mosaic set elicited responses to an average of 8 peptide pools compared to 2 pools for a set of3 natural Env's. Synthetic mosaic HIV -I antigens can therefore induce T-cell responses with expanded breadth and may facilitate the development of effective T -cell-based HIV -1 vaccines.

Korber, Bette [Los Alamos National Laboratory; Fischer, William [Los Alamos National Laboratory; Wallstrom, Timothy [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

73

Protein Bridges DNA Base and Nucleotide Excision Repair Pathways  

NLE Websites -- All DOE Office Websites (Extended Search)

Protein Bridges DNA Base and Nucleotide Excision Repair Pathways Print Protein Bridges DNA Base and Nucleotide Excision Repair Pathways Print Alkyltransferase proteins (AGT) protect cells from the biological effects of DNA damage caused by the addition of alkyl groups (alkylation). Alkyltransferase-like proteins (ATLs) can do the same, but they lack the reactive cysteine residue that allows the alkyltransferase function, and the mechanism for cell protection has remained unknown. To address this mystery, a British-American team lead by researchers at the Scripps Research Institute recently applied a combination of x-ray structural, biochemical, and genetic studies to ATLs in the yeast Schizosaccharomyces pombe without and with damaged DNA. By showing how a process called non-enzymatic nucleotide flipping activates ATL-initiated DNA repair, their results may improve our understanding of genomic integrity and responses to DNA damage relevant to pathogens and cancer development.

74

Protein Bridges DNA Base and Nucleotide Excision Repair Pathways  

NLE Websites -- All DOE Office Websites (Extended Search)

Protein Bridges DNA Base and Nucleotide Excision Repair Pathways Print Protein Bridges DNA Base and Nucleotide Excision Repair Pathways Print Alkyltransferase proteins (AGT) protect cells from the biological effects of DNA damage caused by the addition of alkyl groups (alkylation). Alkyltransferase-like proteins (ATLs) can do the same, but they lack the reactive cysteine residue that allows the alkyltransferase function, and the mechanism for cell protection has remained unknown. To address this mystery, a British-American team lead by researchers at the Scripps Research Institute recently applied a combination of x-ray structural, biochemical, and genetic studies to ATLs in the yeast Schizosaccharomyces pombe without and with damaged DNA. By showing how a process called non-enzymatic nucleotide flipping activates ATL-initiated DNA repair, their results may improve our understanding of genomic integrity and responses to DNA damage relevant to pathogens and cancer development.

75

Protein Bridges DNA Base and Nucleotide Excision Repair Pathways  

NLE Websites -- All DOE Office Websites (Extended Search)

Protein Bridges DNA Base and Nucleotide Excision Repair Pathways Print Protein Bridges DNA Base and Nucleotide Excision Repair Pathways Print Alkyltransferase proteins (AGT) protect cells from the biological effects of DNA damage caused by the addition of alkyl groups (alkylation). Alkyltransferase-like proteins (ATLs) can do the same, but they lack the reactive cysteine residue that allows the alkyltransferase function, and the mechanism for cell protection has remained unknown. To address this mystery, a British-American team lead by researchers at the Scripps Research Institute recently applied a combination of x-ray structural, biochemical, and genetic studies to ATLs in the yeast Schizosaccharomyces pombe without and with damaged DNA. By showing how a process called non-enzymatic nucleotide flipping activates ATL-initiated DNA repair, their results may improve our understanding of genomic integrity and responses to DNA damage relevant to pathogens and cancer development.

76

Energy and Technology Review: Unlocking the mysteries of DNA repair  

SciTech Connect

DNA, the genetic blueprint, has the remarkable property of encoding its own repair following diverse types of structural damage induced by external agents or normal metabolism. We are studying the interplay of DNA damaging agents, repair genes, and their protein products to decipher the complex biochemical pathways that mediate such repair. Our research focuses on repair processes that correct DNA damage produced by chemical mutagens and radiation, both ionizing and ultraviolet. The most important type of DNA repair in human cells is called excision repair. This multistep process removes damaged or inappropriate pieces of DNA -- often as a string of 29 nucleotides containing the damage -- and replaces them with intact ones. We have isolated, cloned, and mapped several human repair genes associated with the nucleotide excision repair pathway and involved in the repair of DNA damage after exposure to ultraviolet light or mutagens in cooked food. We have shown that a defect in one of these repair genes, ERCC2, is responsible for the repair deficiency in one of the groups of patients with the recessive genetic disorder xeroderma pigmentosum (XP group D). We are exploring ways to purify sufficient quantities (milligrams) of the protein products of these and other repair genes so that we can understand their functions. Our long-term goals are to link defective repair proteins to human DNA repair disorders that predispose to cancer, and to produce DNA-repair-deficient mice that can serve as models for the human disorders.

Quirk, W.A.

1993-04-01T23:59:59.000Z

77

Meter Damage: Many customers have questions about who is responsible for repair to the electrical service at their homes. These pages may help to answer  

E-Print Network (OSTI)

Meter Damage: Many customers have questions about who is responsible for repair. weather head stack meter base connectors house knob weather head connectors mast clamp stack meter base meter meter #12; Let's start with definitions: Meter base: This is the metal box mounted

Rose, Annkatrin

78

Cell cycle and DNA damage response regulation by Spy1, and the intersection of FGFR and NFkappaB pathways  

E-Print Network (OSTI)

or presence of 5 g/ml doxycycline. Cell counts were takenafter treatment with 1 g/ml tetracycline or doxycycline.was achieved with doxycycline treatment for h. Cells were

McAndrew, Christopher William

2010-01-01T23:59:59.000Z

79

Cell cycle and DNA damage response regulation by Spy1, and the intersection of FGFR and NFkappaB pathways  

E-Print Network (OSTI)

Bio-Rad). Quantification of NF-kB binding to the probe wasBio-Rad). The average NF-kB binding from three independentBio-Rad). Quantification of NF-kB binding to the probe was

McAndrew, Christopher William

2010-01-01T23:59:59.000Z

80

Cell cycle and DNA damage response regulation by Spy1, and the intersection of FGFR and NFkappaB pathways  

E-Print Network (OSTI)

638: 403-405. Partanen J, Makela TP, Eerola E, et al. (1991)9: 2685-2692. Partanen J, Makela TP, Alitalo R, Lehvaslaiho

McAndrew, Christopher William

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "dna damage response" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Comment on `Nanoconfinement-enhanced conformational response of single DNA molecules to changes in ionic environment'  

E-Print Network (OSTI)

In the present Comment we show that, contrary to the recent findings of Reisner et al. [Phys. Rev. Lett. 99, 058302 (2007)], the excluded volume effect does not play an important role in determining DNA behavior in nanochannels at low ionic strength. We argue that the DNA extension data are described very well without the notion of an effective polymer width using the entropic depletion theory due to Odijk.

Madhavi Krishnan; Eugene P. Petrov

2008-05-14T23:59:59.000Z

82

The cellular Mre11 protein interferes with adenovirus E4 mutant DNA replication  

SciTech Connect

Adenovirus type 5 (Ad5) relocalizes and degrades the host DNA repair protein Mre11, and efficiently initiates viral DNA replication. Mre11 associates with Ad E4 mutant DNA replication centers and is important for concatenating viral genomes. We have investigated the role of Mre11 in the E4 mutant DNA replication defect. RNAi-mediated knockdown of Mre11 dramatically rescues E4 mutant DNA replication in cells that do or do not concatenate viral genomes, suggesting that Mre11 inhibits DNA replication independent of genome concatenation. The mediator of DNA damage checkpoint 1 (Mdc1) protein is involved in recruiting and sustaining Mre11 at sites of DNA damage following ionizing radiation. We observe foci formation by Mdc1 in response to viral infection, indicating that this damage response protein is activated. However, knockdown of Mdc1 does not prevent Mre11 from localizing at viral DNA replication foci or rescue E4 mutant DNA replication. Our results are consistent with a model in which Mre11 interferes with DNA replication when it is localized at viral DNA replication foci.

Mathew, Shomita S. [Department of Microbiology, 32 Pearson Hall, Miami University, Oxford OH 45056 (United States); Bridge, Eileen [Department of Microbiology, 32 Pearson Hall, Miami University, Oxford OH 45056 (United States)], E-mail: BridgeE@muohio.edu

2007-09-01T23:59:59.000Z

83

doi:10.1093/nar/gkr435 Role for hACF1 in the G2/M damage checkpoint  

E-Print Network (OSTI)

Active chromatin remodelling is integral to the DNA damage response in eukaryotes, as damage sensors, signalling molecules and repair enzymes gain access to lesions. A variety of nucleosome remodelling complexes is known to promote different stages of DNA repair. The nucleosome sliding factors CHRAC/ACF of Drosophila are involved in chromatin organization during development. Involvement of corresponding hACF1-containing mammalian nucleosome sliding factors in replication, transcription and very recently also non-homologous end-joining of DNA breaks have been suggested. We now found that hACF1-containing factors are more generally involved in the DNA damage response. hACF1 depletion increases apoptosis, sensitivity to radiation and compromises the G2/M arrest that is activated in response to UV- and X-rays. In the absence of hACF1, cH2AX and CHK2ph signals are diminished. hACF1 and its ATPase partner SNF2H rapidly accumulate at sites of laser-induced DNA damage. hACF1 is also required for a tight checkpoint that is induced upon replication fork collapse. ACF1depleted cells that are challenged with aphidicolin enter mitosis despite persistence of lesions and accumulate breaks in metaphase chromosomes. hACF1-containing remodellers emerge as global facilitators of the cellular response to a variety of different types of DNA damage.

Sara Snchez-molina; Oliver Mortusewicz; Batrice Bieber; Susanne Auer; Maren Eckey; Heinrich Leonhardt; Anna A. Friedl; Peter B. Becker

2011-01-01T23:59:59.000Z

84

Formation of methyl ester of 2-methylglyceric acid from thymine glycol residues: a convenient new method for determining radiation damage to DNA  

Science Conference Proceedings (OSTI)

Thymine glycol residues in DNA or thymidine were converted to methyl 2-methylglycerate by reaction with alkaline borohydride followed by methanolic HCl. The product was labeled either from (/sup 3/H)DNA or from (/sup 3/H)borohydride and was followed by cochromatography with authentic /sup 14/C-labeled material. Following acid hydrolysis, the identity of 2-methylglyceric acid was confirmed by high-resolution mass spectrometry, NMR, IR, and elemental analysis. Treatment of DNA or thymidine with X-irradiation, with H/sub 2/O/sub 2/ and Fe/sup 2 +/, with H/sub 2/O/sub 2/, Cu/sup 2 +/, and ascorbate, and with H/sub 2/O/sub 2/ and ultraviolet light, permanganate, or sonication all produced methyl 2-methylglycerate in varying amounts after alkaline borohydride and methanolic HCl, whereas untreated DNA did not. The data indicate that certain oxidants including hydroxyl radicals generated by chemical means or from radiolysis of water convert thymine residues to thymine glycols in DNA, which can be determined as methyl 2-methylglycerate.

Schellenberg, K.A.; Shaeffer, J.

1986-04-08T23:59:59.000Z

85

The Response of Damaging Winds of a Simulated Tropical Cyclone to Finite-Amplitude Perturbations of Different Variables  

Science Conference Proceedings (OSTI)

Four-dimensional variational data assimilation (4DVAR) is an established data assimilation method that finds the finite-amplitude perturbation that best fits observations consistent with a priori information and model dynamics. The response of a ...

R. N. Hoffman; J. M. Henderson; S. M. Leidner; C. Grassotti; T. Nehrkorn

2006-07-01T23:59:59.000Z

86

Low Dose Radiation Research Program: Mechanisms of Tissue Response to Low  

NLE Websites -- All DOE Office Websites (Extended Search)

Tissue Response to Low Dose Radiation Tissue Response to Low Dose Radiation Mary Helen Barcellos-Hoff Lawrence Berkeley National Laboratory Why This Project? In the past, the effects of ionizing radiation on humans has been attributed in great part to its ability to damage DNA, which transmits information from cell to cell, and generation to generation. Damaged DNA can lead to cell death or perpetuate the damage to daughter cells and to future generations. In addition to the information contained with the genome (i.e., DNA sequence), information directing cell behavior and tissue function is also stored outside the DNA. The success in cloning sheep from the DNA contained in the nucleus of an adult cell shows how important signals from the outside are in defining how the genome is expressed. This

87

Human AlkB Homolog ABH8 Is a tRNA Methyltransferase Required for Wobble Uridine Modification and DNA Damage Survival  

E-Print Network (OSTI)

tRNA nucleosides are extensively modified to ensure their proper function in translation. However, many of the enzymes responsible for tRNA modifications in mammals await identification. Here, we show that human AlkB homolog ...

Fu, Dragony

88

Guest Editorial: Laser Damage  

SciTech Connect

Laser damage of optical materials, first reported in 1964, continues to limit the output energy and power of pulsed and continuous-wave laser systems. In spite of some 48 years of research in this area, interest from the international laser community to laser damage issues remains at a very high level and does not show any sign of decreasing. Moreover, it grows with the development of novel laser systems, for example, ultrafast and short-wavelength lasers that involve new damage effects and specific mechanisms not studied before. This interest is evident from the high level of attendance and presentations at the annual SPIE Laser Damage Symposium (aka, Boulder Damage Symposium) that has been held in Boulder, Colorado, since 1969. This special section of Optical Engineering is the first one devoted to the entire field of laser damage rather than to a specific part. It is prepared in response to growing interest from the international laser-damage community. Some papers in this special section were presented at the Laser Damage Symposium; others were submitted in response to the general call for papers for this special section. The 18 papers compiled into this special section represent many sides of the broad field of laser-damage research. They consider theoretical studies of the fundamental mechanisms of laser damage including laser-driven electron dynamics in solids (O. Brenk and B. Rethfeld; A. Nikiforov, A. Epifanov, and S. Garnov; T. Apostolova et al.), modeling of propagation effects for ultrashort high-intensity laser pulses (J. Gulley), an overview of mechanisms of inclusion-induced damage (M. Koldunov and A. Manenkov), the formation of specific periodic ripples on a metal surface by femtosecond laser pulses (M. Ahsan and M. Lee), and the laser-plasma effects on damage in glass (Y. Li et al). Material characterization is represented by the papers devoted to accurate and reliable measurements of absorption with special emphasis on thin films (C. Mhlig and S. Bublitz; B. Cho, E. Danielewicz, and J. Rudisill; W. Palm et al; and J. Lu et al.). Statistical treatment of measurements of the laser-damage threshold (J. Arenberg) and the relationship to damage mechanisms (F. Wagner et al.) represent the large subfield of laser-damage measurements. Various aspects of multilayer coating and thin-film characterization are considered in papers by B. Cho, J. Rudisill, and E. Danielewicz (spectral shift in multilayer mirrors) and R. Weber et al. (novel approach to damage studies based on third-harmonic generation microscopy). Of special interest for readers is the paper by C. Stolz that summarizes the results of four thin-film damage competitions organized as a part of the Laser Damage Symposium. Another paper is devoted to thermal annealing of damage precursors (N. Shen et al.). Finally, the influence of nano-size contamination on initiation of laser damage by ultrashort pulses is considered in paper of V. Komolov et al.

Vitaly Gruzdev, Michelle D. Shinn

2012-12-01T23:59:59.000Z

89

Recombinant methods for screening human DNA excision repair proficiency  

SciTech Connect

A method for measuring DNA excision repair in response to ultraviolet radiation (UV)-induced DNA damage has been developed, validated, and field-tested in cultured human lymphocytes. The methodology is amenable to population-based screening and should facilitate future epidemiologic studies seeking to investigate associations between excision repair proficiency and cancer susceptibility. The impetus for such endeavors derives from the belief that the high incidence of skin cancer in the genetic disorder xeroderma pigmentosum (XP) primarily is a result of the reduced capacity of patients cells to repair UV-induced DNA damage. For assay, UV-irradiated non-replicating recombinant plasmid DNA harboring a chloramphenicol acetyltransferase (CAT) indicator gene is introduced into lymphocytes using DEAE-dextran short-term transfection conditions. Exposure to UV induces transcriptionally-inactivating DNA photoproducts in the plasmid DNA which inactivate CAT gene expression. Excision repair of the damaged CAT gene is monitored indirectly as a function of reactivated CAT enzyme activity following a 40 hour repair/expression incubation period.

Athas, W.F.

1988-01-01T23:59:59.000Z

90

Roles of the Tetrahymena thermophila type I element binding factor, TIF1, in DNA replication and genome stability  

E-Print Network (OSTI)

The Tetrahymena thermophila rDNA minichromosome has been used as a model system for studying DNA replication. Previous studies have identified cis-acting replication determinants within the rDNA origin and promoter region including the type I element that is essential for replication initiation, fork progression and promoter activation. TIF1 is a non-ORC single strand-binding protein that binds the type I element in vivo. TIF1 binds opposing strands at the origin and promoter regions indicating that it may play a role in selectively marking these regions. In this dissertation, I use gene disruption to elucidate the role of TIF1 in replication. This work reveals that TIF1 represses rDNA origin firing, and is required for proper macronuclear S phase progression and division. Replication at the rDNA origin initiates precociously despite the observation that TIF1 mutants exhibit an elongated macronuclear S phase and a diminished rate of DNA replication. The amitotic macronucleus also displays delayed and abnormal division even though cells exit S phase with a wild-type macronuclear DNA content. Nuclear defects are also evident in the diploid micronucleus as TIF1 mutants contain fewer micronuclear chromosomes and are unable to pass genetic information to progeny. This defect is progressive as clonal mutant lines exhibit micronuclear instability during subsequent vegetative cell cycling. This work reveals that these macro- and micronuclear phenotypes may be the result of DNA damage as TIF1 mutants are hypersensitive to DNA damaging agents. This suggests that TIF1 mutants may have defects in the DNA damage response pathway. TIF1-deficient cells also incur DNA damage with no exogenous damaging agents. I propose that micro- and macronuclear defects witnessed in TIF1 mutant cells result from cells exiting S phase with compromised chromosomes due to the accumulation of DNA damage. Furthermore, TIF1 appears to play a role in the prevention, recognition or repair of DNA damage in addition to regulating rDNA replication and cell cycle progression and division. Additionally, TIF1 plays an essential role in the faithful propagation of both the macro- and micronuclear genomes.

Morrison, Tara Laine

2005-08-01T23:59:59.000Z

91

Low Dose Radiation Research Program: Modeling the Physics of Damage Cluster  

NLE Websites -- All DOE Office Websites (Extended Search)

Modeling the Physics of Damage Cluster Formation in a Cellular Environment Modeling the Physics of Damage Cluster Formation in a Cellular Environment Larry Toburen East Carolina University Why This Project Modern tools of radiobiology are leading to many new discoveries regarding how cells and tissues respond to radiation exposure. We can now irradiate single cells and observe responses in adjacent cells. We can also measure clusters of radiation damage produced in DNA. The primary tools available to describe the initial spatial pattern of damage formed by the absorption of ionizing radiation are based on (MC) Monte Carlo simulations of the structure of charged particle tracks. Although many MC codes exist and considerable progress is being made in the incorporation of detailed macromolecular target structures into these codes, much of the interaction

92

Cambium Damage  

NLE Websites -- All DOE Office Websites (Extended Search)

Cambium Damage Cambium Damage Name: Jamie Location: N/A Country: N/A Date: N/A Question: If the bark from the lower part of trees (elm trees) is almost completly removed (in this case by animals)to a height of about 8ft, is it possible that the trees will still live? What can be done to help the trees? Replies: If the tree has been girdled, that is, the bark and cambium layer beneath it, has been removed completely around the tree, then it will die. If there is any portion of the bark remaining it may live, but if that remaining is small it probably will die fairly soon due to general decline. If the cambium layer has not been destroyed it may recover, but once the bark is stripped away it is most likely doomed because of the likelihood of invasion by fungi, insects, etc. A local forester or landscaper might be able to offer more help if they see it.

93

Local chromatin structure of heterochromatin regulates repeatedDNA stability, nucleolus structure, and genome integrity  

SciTech Connect

Heterochromatin constitutes a significant portion of the genome in higher eukaryotes; approximately 30% in Drosophila and human. Heterochromatin contains a high repeat DNA content and a low density of protein-encoding genes. In contrast, euchromatin is composed mostly of unique sequences and contains the majority of single-copy genes. Genetic and cytological studies demonstrated that heterochromatin exhibits regulatory roles in chromosome organization, centromere function and telomere protection. As an epigenetically regulated structure, heterochromatin formation is not defined by any DNA sequence consensus. Heterochromatin is characterized by its association with nucleosomes containing methylated-lysine 9 of histone H3 (H3K9me), heterochromatin protein 1 (HP1) that binds H3K9me, and Su(var)3-9, which methylates H3K9 and binds HP1. Heterochromatin formation and functions are influenced by HP1, Su(var)3-9, and the RNA interference (RNAi) pathway. My thesis project investigates how heterochromatin formation and function impact nuclear architecture, repeated DNA organization, and genome stability in Drosophila melanogaster. H3K9me-based chromatin reduces extrachromosomal DNA formation; most likely by restricting the access of repair machineries to repeated DNAs. Reducing extrachromosomal ribosomal DNA stabilizes rDNA repeats and the nucleolus structure. H3K9me-based chromatin also inhibits DNA damage in heterochromatin. Cells with compromised heterochromatin structure, due to Su(var)3-9 or dcr-2 (a component of the RNAi pathway) mutations, display severe DNA damage in heterochromatin compared to wild type. In these mutant cells, accumulated DNA damage leads to chromosomal defects such as translocations, defective DNA repair response, and activation of the G2-M DNA repair and mitotic checkpoints that ensure cellular and animal viability. My thesis research suggests that DNA replication, repair, and recombination mechanisms in heterochromatin differ from those in euchromatin. Remarkably, human euchromatin and fly heterochromatin share similar features; such as repeated DNA content, intron lengths and open reading frame sizes. Human cells likely stabilize their DNA content via mechanisms and factors similar to those in Drosophila heterochromatin. Furthermore, my thesis work raises implications for H3K9me and chromatin functions in complex-DNA genome stability, repeated DNA homogenization by molecular drive, and in genome reorganization through evolution.

Peng, Jamy C.

2007-05-05T23:59:59.000Z

94

Excitation optimization for damage detection  

SciTech Connect

A technique is developed to answer the important question: 'Given limited system response measurements and ever-present physical limits on the level of excitation, what excitation should be provided to a system to make damage most detectable?' Specifically, a method is presented for optimizing excitations that maximize the sensitivity of output measurements to perturbations in damage-related parameters estimated with an extended Kalman filter. This optimization is carried out in a computationally efficient manner using adjoint-based optimization and causes the innovations term in the extended Kalman filter to be larger in the presence of estimation errors, which leads to a better estimate of the damage-related parameters in question. The technique is demonstrated numerically on a nonlinear 2 DOF system, where a significant improvement in the damage-related parameter estimation is observed.

Bement, Matthew T [Los Alamos National Laboratory; Bewley, Thomas R [UCSD

2009-01-01T23:59:59.000Z

95

DNA Record  

Science Conference Proceedings (OSTI)

... 4. Field 18.004: Source agency/SRC 5. Field 18.005: DNA Record Header Information (DRI) ... Field 18.005: DNA Record Header Information (DRI) ...

2010-08-03T23:59:59.000Z

96

Enhancement of DNA repair capacity of mammalian cells by carcinogen treatment  

SciTech Connect

To determine whether DNA excision repair is enhanced in mammalian cells in response to DNA damage, as it is in bacteria as part of the SOS response, we used an expression vector-host cell reactivation assay to measure cellular DNA repair capacity. When UV-damaged chloramphenicol acetyltransferase (CAT) vector DNA was introduced into monkey cells (CV-1), the level of CAT activity was inversely related to the UV fluence due to inhibition of CAT gene expression by UV photoproducts. When CV-1 cells were treated with either UV radiation or mitomycin C, 24-48 h before transfection, CAT expression from the UV-irradiated plasmid was increased. This increase also occurred in a line of normal human cells, but not in repair-deficient human xeroderma pigmentosum cells. We confirmed that this increase in CAT expression was due to repair, and not to production of damage-free templates by recombination; the frequency of generation of supF+ recombinants after transfection with UV-irradiated pZ189 vectors carrying different point mutations in the supF gene did not significantly increase in carcinogen-treated CV-1 cells. From these results we conclude that carcinogen treatment enhances the excision-repair capacity of normal mammalian cells.

Protic, M.; Roilides, E.; Levine, A.S.; Dixon, K.

1988-07-01T23:59:59.000Z

97

YabA of Bacillus subtilis controls DnaA-mediated replication initiation but not the transcriptional response to replication stress  

E-Print Network (OSTI)

yabA encodes a negative regulator of replication initiation in Bacillus subtilis and homologues are found in many other Gram-positive species. YabA interacts with the ?-processivity clamp (DnaN) of DNA polymerase and with ...

Grossman, Alan D.

98

Accumulation of DNA Double-Strand Breaks in Normal Tissues After Fractionated Irradiation  

SciTech Connect

Purpose: There is increasing evidence that genetic factors regulating the recognition and/or repair of DNA double-strand breaks (DSBs) are responsible for differences in radiosensitivity among patients. Genetically defined DSB repair capacities are supposed to determine patients' individual susceptibility to develop adverse normal tissue reactions after radiotherapy. In a preclinical murine model, we analyzed the impact of different DSB repair capacities on the cumulative DNA damage in normal tissues during the course of fractionated irradiation. Material and Methods: Different strains of mice with defined genetic backgrounds (SCID{sup -/-} homozygous, ATM{sup -/-} homozygous, ATM{sup +/-}heterozygous, and ATM{sup +/+}wild-type mice) were subjected to single (2 Gy) or fractionated irradiation (5 x 2 Gy). By enumerating gammaH2AX foci, the formation and rejoining of DSBs were analyzed in organs representative of both early-responding (small intestine) and late-responding tissues (lung, kidney, and heart). Results: In repair-deficient SCID{sup -/-} and ATM{sup -/-}homozygous mice, large proportions of radiation-induced DSBs remained unrepaired after each fraction, leading to the pronounced accumulation of residual DNA damage after fractionated irradiation, similarly visible in early- and late-responding tissues. The slight DSB repair impairment of ATM{sup +/-}heterozygous mice was not detectable after single-dose irradiation but resulted in a significant increase in unrepaired DSBs during the fractionated irradiation scheme. Conclusions: Radiation-induced DSBs accumulate similarly in acute- and late-responding tissues during fractionated irradiation, whereas the whole extent of residual DNA damage depends decisively on the underlying genetically defined DSB repair capacity. Moreover, our data indicate that even minor impairments in DSB repair lead to exceeding DNA damage accumulation during fractionated irradiation and thus may have a significant impact on normal tissue responses in clinical radiotherapy.

Ruebe, Claudia E., E-mail: claudia.ruebe@uks.e [Department of Radiation Oncology, Saarland University, Homburg/Saar (Germany); Fricke, Andreas; Wendorf, Juliane; Stuetzel, Annika; Kuehne, Martin [Department of Radiation Oncology, Saarland University, Homburg/Saar (Germany); Ong, Mei Fang [Institute of Medical Biometrics, Epidemiology and Medical Informatics, Saarland University, Homburg/Saar (Germany); Lipp, Peter [Institute for Molecular Cell Biology, Saarland University, Homburg/Saar (Germany); Ruebe, Christian [Department of Radiation Oncology, Saarland University, Homburg/Saar (Germany)

2010-03-15T23:59:59.000Z

99

WHERE MULTIFUNCTIONAL DNA REPAIR PROTEINS MEET: MAPPING THE INTERACTION DOMAINS BETWEEN XPG AND WRN  

Science Conference Proceedings (OSTI)

The rapid recognition and repair of DNA damage is essential for the maintenance of genomic integrity and cellular survival. Multiple complex and interconnected DNA damage responses exist within cells to preserve the human genome, and these repair pathways are carried out by a specifi c interplay of protein-protein interactions. Thus a failure in the coordination of these processes, perhaps brought about by a breakdown in any one multifunctional repair protein, can lead to genomic instability, developmental and immunological abnormalities, cancer and premature aging. This study demonstrates a novel interaction between two such repair proteins, Xeroderma pigmentosum group G protein (XPG) and Werner syndrome helicase (WRN), that are both highly pleiotropic and associated with inherited genetic disorders when mutated. XPG is a structure-specifi c endonuclease required for the repair of UV-damaged DNA by nucleotide excision repair (NER), and mutations in XPG result in the diseases Xeroderma pigmentosum (XP) and Cockayne syndrome (CS). A loss of XPG incision activity results in XP, whereas a loss of non-enzymatic function(s) of XPG causes CS. WRN is a multifunctional protein involved in double-strand break repair (DSBR), and consists of 35 DNA-dependent helicase, 35 exonuclease, and single-strand DNA annealing activities. Nonfunctional WRN protein leads to Werner syndrome, a premature aging disorder with increased cancer incidence. Far Western analysis was used to map the interacting domains between XPG and WRN by denaturing gel electrophoresis, which separated purifi ed full length and recombinant XPG and WRN deletion constructs, based primarily upon the length of each polypeptide. Specifi c interacting domains were visualized when probed with the secondary protein of interest which was then detected by traditional Western analysis using the antibody of the secondary protein. The interaction between XPG and WRN was mapped to the C-terminal region of XPG as well as the C-terminal region of WRN. The physical interaction between XPG and WRN links NER, (made evident by the disease XP) with DSBR, which imparts additional knowledge of the overlapping nature of these two proteins and the previously distinct DNA repair pathways they are associated with. Since genomic integrity is constantly threatened by both endogenous and exogenous (internal and external) damage, understanding the roles of these proteins in coordinating DNA repair processes with replication will signifi cantly further understanding how defects instigate physiological consequences in response to various DNA damaging sources. This ultimately contributes to our understanding of cancer and premature aging.

Rangaraj, K.; Cooper, P.K.; Trego, K.S.

2009-01-01T23:59:59.000Z

100

DNA Extraction  

NLE Websites -- All DOE Office Websites (Extended Search)

DNA Extraction DNA Extraction Being able to extract deoxyribonucleic acid (DNA) is important for a number of reasons. By studying DNA, scientists can identify genetic disorders or diseases, and they can also possibly find cures for them by manipulating or experimenting with this DNA. At the Laboratory, researchers have studied DNA to detect biothreat agents in environmental and forensic samples. Scientists also are studying how human DNA may be destroyed by certain types of electromagnetic waves at certain frequencies. Classroom Activity: This activity is about the extraction of DNA from strawberries. Strawberries are a great fruit to use for this lesson because each student can work on his or her own. Strawberries are recommended because they yield more DNA than any other fruit. Strawberries are octoploid, which means that they have eight copies of each

Note: This page contains sample records for the topic "dna damage response" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Transcriptional and Epigenetic Responses of Human Cells to Low Dose  

NLE Websites -- All DOE Office Websites (Extended Search)

Transcriptional and Epigenetic Responses of Human Cells to Low Dose Transcriptional and Epigenetic Responses of Human Cells to Low Dose Ionizing Radiation Identified through High Throughput ChIP-Seq Analysis Carl Anderson Brookhaven National Laboratory Abstract The major consequence of human exposures to ionizing radiation (IR) is considered to be an increased incidence of cancer (Brenner et al., 2003). Exposure of cells to 1 Gy of IR produces approximately 40 double-stranded breaks, 1000 single-stranded breaks, and 1000 damaged bases per genome equivalent (Pandita and Richardson, 2009); however, most direct DNA damage is rapidly repaired. Exposure to IR also induces epigenetic changes including both increases and decreases in DNA methylation, and increasing evidence suggests that epigenetic changes can both initiate cancer and

102

The critical roles of pre-replicative complex (pre-RC) component, Cdc6, in DNA replication and checkpoint response in human cells  

E-Print Network (OSTI)

function as the replicative helicase in eukaryotic cells (a part of the hexameric helicase complex, is a transcriptionDNA-dependent ATPase and helicase activity, functions as a

Lau, Eric Kirk

2008-01-01T23:59:59.000Z

103

DNA Biometrics  

Science Conference Proceedings (OSTI)

... presentation at Advances in Forensic DNA Analysis workshop held at the American Academy of Forensic Sciences meeting (Seattle, WA), February ...

2013-03-15T23:59:59.000Z

104

Forensic DNA:  

Science Conference Proceedings (OSTI)

... January 17, 2008 Press Release From Mayor Bloomberg's STATE OF THE CITY ADDRESS Efforts towards Portable/Mobile DNA Devices ...

2008-09-29T23:59:59.000Z

105

Schools - CPU Damage  

Science Conference Proceedings (OSTI)

This power quality (PQ) case study presents the investigation of computers in a school computer lab that were being damaged.

2003-12-31T23:59:59.000Z

106

Corrosion and Hydrogen Damage  

Science Conference Proceedings (OSTI)

Mar 5, 2013 ... Advanced Materials and Reservoir Engineering for Extreme Oil & Gas Environments: Corrosion and Hydrogen Damage Sponsored by: TMS...

107

Classifying aging genes into DNA repair or non-DNA repair-related categories  

Science Conference Proceedings (OSTI)

The elderly population in almost every country is growing faster than ever before. However, our knowledge about the aging process is still limited despite decades of studies on this topic. In this report, we focus on the gradual accumulation of DNA damage ... Keywords: DNA-repair, aging, classification, feature selection, random forest

Yaping Fang, Xinkun Wang, Elias K. Michaelis, Jianwen Fang

2013-07-01T23:59:59.000Z

108

RAPID DAMAGE ASSESSMENT FROM HIGH RESOLUTION IMAGERY  

SciTech Connect

Disaster impact modeling and analysis uses huge volumes of image data that are produced immediately following a natural or an anthropogenic disaster event. Rapid damage assessment is the key to time critical decision support in disaster management to better utilize available response resources and accelerate recovery and relief efforts. But exploiting huge volumes of high resolution image data for identifying damaged areas with robust consistency in near real time is a challenging task. In this paper, we present an automated image analysis technique to identify areas of structural damage from high resolution optical satellite data using features based on image content.

Vijayaraj, Veeraraghavan [ORNL; Bright, Eddie A [ORNL; Bhaduri, Budhendra L [ORNL

2008-01-01T23:59:59.000Z

109

Application of nonlinear wave modulation spectroscopy to discern material damage  

SciTech Connect

Materials containing structural damage have a far greater nonlinear elastic response than materials with no structural damage. This is the basis for nonlinear wave diagnostics of damage, methods which are remarkably sensitive to the detection and progression of damage in materials. Here the authors describe one nonlinear method, the application of harmonics and sum and difference frequency to discern damage in materials. The method is termed Nonlinear Wave Modulation Spectroscopy (NWMS). It consists of exciting a sample with continuous waves of two separate frequencies simultaneously, and inspecting the harmonics of the two waves, and their sum and difference frequencies (sidebands). Undamaged materials are essentially linear in their response to the two waves, while the same material, when damaged, becomes highly nonlinear, manifested by harmonics and sideband generation. The authors illustrate the method by experiments on uncracked and cracked plexiglass and sandstone samples, and by applying it to intact and damaged engine components.

Johnson, P.A. [Los Alamos National Lab., NM (United States); Sutin, A. [Stevens Inst. of Tech., Hoboken, NJ (United States); Abeele, K.E.A. van den [Catholic Univ. Leuven (Belgium). Dept. of Building Physics

1999-04-01T23:59:59.000Z

110

Connections Between the TCR Proteins XPG and CSB, Repair of Oxidative DNA  

NLE Websites -- All DOE Office Websites (Extended Search)

Connections Between the TCR Proteins XPG and CSB, Repair of Oxidative DNA Connections Between the TCR Proteins XPG and CSB, Repair of Oxidative DNA Base Damage, and the Radio-Adaptive Response Helen Budworth, Brett Haltiwanger, Altaf Sarker, Torsten Grösser, Björn Rydberg, and Priscilla K. Cooper* Life Sciences Division, MailStop 74-157, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; *Corresponding author A key question that is central to accurately assessing human health risks from environmentally relevant low level (low dose, low dose rate) exposures to ionizing radiation is whether cellular responses measured at the higher doses for which there are strong epidemiological health data and the high doses commonly used in laboratory experiments extrapolate in a linear fashion to low doses. Recent data suggest that they may not. For example, low-dose hypersensitivity for

111

R-damage cassette (incorporated brass sleeve)  

SciTech Connect

The R-Damage series of ten experiments is part of a long-term collaboration with RFNC/VNIIEF in pulsed power technology. These experiments use a cylindrical configuration to study spallation damage, which allows for a natural recollection of the damaged material under proper driving conditions and post-shot collection of the damaged target material for subsequent metallographic analysis. Dynamic in-situ experimental velocimetry diagnostics are also employed. LANL is responsible for the design of the experimental load and velocimetry system. VNIIEF is responsible for the design and construction of the driving explosive magnetic generator. Eight of the experiments in the planned series have been completed. Thus far, data has been collected about failure initiation of a well-characterized material (aluminum) in a cylindrical geometry, the behavior of material recollected after damage from pressures in the damage initiation regime, and the behavior of material recollected after complete failure. The final two experiments will continue the study of material recollected after complete failure. The load assembly shown is similar to that employed in the previous two experiments, with some modiflications for easier assembly.

Griego, Jeffrey Randall [Los Alamos National Laboratory

2011-01-07T23:59:59.000Z

112

DNA Activity  

NLE Websites -- All DOE Office Websites (Extended Search)

DNA Activity DNA Activity Name: Sara Location: N/A Country: N/A Date: N/A Question: Is DNA an anion or a cation? I thought since it was negatively charged it was an anion but mt teacher in class today said it was a cation because negatively charged molecules logically migrate to the positively charged plate of the cathode, ie molecules that migrate towards a cathode are cations. Where is the error in my logic or there error in my logic? Replies: DNA is negatively charged due to the phosphate ions present in the ribose-phosphate backbone. It moves towards the positive pole during electrophoresis. The definition kation/anion is confusing because: 1. a cation moves to the cathode 2. the cathode is negative, thus 3. a cation is positive DNA is an anion. The confusion is that a cathode is negative, but a cation is positively charged. For that reason these terms are not generally used in this context.

113

Primary Radiation Damage Formation  

SciTech Connect

The physical processes that give rise to changes in the microstructure, and the physical and mechanical properties of materials exposed to energetic particles are initiated by essentially elastic collisions between atoms in what has been called an atomic displacement cascade. The formation and evolution of this primary radiation damage mechanism are described to provide an overview of how stable defects are formed by displacement cascades, as well as the nature and morphology of the defects themselves. The impact of the primary variables cascade energy and irradiation temperature are discussed, along with a range of secondary factors that can influence damage formation.

Stoller, Roger E [ORNL

2012-01-01T23:59:59.000Z

114

DNA Damage after Continuous Irradiation: Yanch and Engelward Respond  

E-Print Network (OSTI)

We thank Beyea for his comments and would like to respond, in particular, regarding the works he cites in his letter. First, the results of our study are, in fact, consistent with the findings of many human epidemiologic ...

Yanch, Jacquelyn C.

115

Links Between DNA Damage and Breast Cancer Studied  

Science Conference Proceedings (OSTI)

... Genetic changes in this connective tissue that supports the breast's network of glands and ducts have been reported to precede the malignant ...

2012-06-28T23:59:59.000Z

116

Impact of DNA damage proteins on the adenoviral lifecycle  

E-Print Network (OSTI)

G. , Bridge, G. , and Flint, S.J. (2007). The adenovirus L4Oncogene 26, 4797-4805. Flint, S.J. , and Gonzalez, R.A. (782-783. Gonzalez, R.A. , and Flint, S.J. (2002). Effects of

Lakdawala, Seema Sailesh

2009-01-01T23:59:59.000Z

117

Public Comment re NOI on Convention on Supplementary Compensation for Nuclear Damage  

Energy.gov (U.S. Department of Energy (DOE))

ENERGYSOLUTIONS' Comment in Response to Notice of Inquiry, Convention on Supplementary Compensation for Nuclear Damage Contingent Cost Allocation -75 FR 43945

118

Convention on Supplementary Compensation for Nuclear Damage Contingent Cost Allocation, Section 934  

Energy.gov (U.S. Department of Energy (DOE))

LES comments in response to Notice of Inquiry on Convention on Supplementary Compensation for Nuclear Damage Contingent Cost Allocation, Section 934

119

Microfluidic DNA sample preparation method and device  

DOE Patents (OSTI)

Manipulation of DNA molecules in solution has become an essential aspect of genetic analyses used for biomedical assays, the identification of hazardous bacterial agents, and in decoding the human genome. Currently, most of the steps involved in preparing a DNA sample for analysis are performed manually and are time, labor, and equipment intensive. These steps include extraction of the DNA from spores or cells, separation of the DNA from other particles and molecules in the solution (e.g. dust, smoke, cell/spore debris, and proteins), and separation of the DNA itself into strands of specific lengths. Dielectrophoresis (DEP), a phenomenon whereby polarizable particles move in response to a gradient in electric field, can be used to manipulate and separate DNA in an automated fashion, considerably reducing the time and expense involved in DNA analyses, as well as allowing for the miniaturization of DNA analysis instruments. These applications include direct transport of DNA, trapping of DNA to allow for its separation from other particles or molecules in the solution, and the separation of DNA into strands of varying lengths.

Krulevitch, Peter A. (Pleasanton, CA); Miles, Robin R. (Danville, CA); Wang, Xiao-Bo (San Diego, CA); Mariella, Raymond P. (Danville, CA); Gascoyne, Peter R. C. (Bellaire, TX); Balch, Joseph W. (Livermore, CA)

2002-01-01T23:59:59.000Z

120

Radiation and viral DNA  

NLE Websites -- All DOE Office Websites (Extended Search)

Radiation and viral DNA Radiation and viral DNA Name: Loretta L Lamb Age: N/A Location: N/A Country: N/A Date: N/A Question: Can viral DNA be changed through exposure to radiation? If so, what type of radiation will do this? Can these irradiated viruses cause changes in the genome of any human cells they may infect? Can these (or any) viruses actually cause cancer, or do they merely act as triggering devices for cancer? Replies: In theory, any nucleic acid (viral or otherwise) can be changed by exposure to many kinds of radiation. Depending on the type of virus, these may then change the human cells that they infect. Although there are many different things that are being implicated in causing cancers, it looks like a fairly common model involves the sequential "knockout" of several human genes. Viruses may be one cause of such gene changes, radiation and other environmental causes may also contribute. Some of these changes may be inherited through families, so it becomes more likely that the environmental factors may happen to "hit" the right places in cells to cause cancers in these families. If you ask something more specific, perhaps I can focus my response a bit more

Note: This page contains sample records for the topic "dna damage response" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Market Damages and the Economic Waste Fallacy  

E-Print Network (OSTI)

Robert E. Scott, The Case for Market Damages; Revisiting thethey pay less than full market damages but when buyerssellers recover full market damages. As a consequence,

Scott, Robert E.; Schwartz, Alan

2008-01-01T23:59:59.000Z

122

Cisplatin-induced nucleosome and RNA polymerase II modification mediate cellular response to the drug  

E-Print Network (OSTI)

(cont.) with recombinant material. The in vitro system established in this study will facilitate the investigation of platinum-DNA damage by DNA repair processes and help elucidate the role of specific post-translational ...

Wang, Dong, 1975-

2004-01-01T23:59:59.000Z

123

The DNA project - CECM  

E-Print Network (OSTI)

Software-package files: dna6.zip (for Maple 6), dna7.zip (for Maple 7). Contents: DNA routines, Release 1.04 ( last updated Nov/06/2001 ). Changes over...

124

Identifying structural damage from images  

E-Print Network (OSTI)

Photographs of damaged buildings in Bam, Iran. . . . . . . .patches of Bam, Iran. . . . . . . . . Photo pictures ofBitemporal images of an urban region of Bam, Iran. . . . .

Chen, ZhiQiang

2009-01-01T23:59:59.000Z

125

Corrosion Damage Models and Sustainability  

Science Conference Proceedings (OSTI)

Presentation Title, Corrosion Damage Models and Sustainability ... Abstract Scope, The ability of industry to make sustainable choices in the future that optimize...

126

XRCC1 & DNA MTases : direct and indirect modulation of inflammation-induced DNA damage  

E-Print Network (OSTI)

Cancer causes 13% of all deaths worldwide. Inflammation-mediated cancer accounts for ~15% of all malignancies, strongly necessitating investigation of the molecular interactions at play. Inflammatory reactive oxygen and ...

Mutamba, James T. (James Tendai)

2011-01-01T23:59:59.000Z

127

Clinical DNA Online  

Science Conference Proceedings (OSTI)

Welcome to the NIST Clinical DNA Information Resource. ... Future materials have progress updates. General Information. ...

2013-04-26T23:59:59.000Z

128

Quantitative DNA fiber mapping  

DOE Patents (OSTI)

The present invention relates generally to the DNA mapping and sequencing technologies. In particular, the present invention provides enhanced methods and compositions for the physical mapping and positional cloning of genomic DNA. The present invention also provides a useful analytical technique to directly map cloned DNA sequences onto individual stretched DNA molecules.

Gray, Joe W. (San Francisco, CA); Weier, Heinz-Ulrich G. (Oakland, CA)

1998-01-01T23:59:59.000Z

129

Laser-Induced Damage of Calcium Fluoride  

Science Conference Proceedings (OSTI)

As advances continue to be made in laser technology there is an increasing demand for materials that have high thresholds for laser-induced damage. Laser damage occurs when light is absorbed, creating defects in the crystal lattice. These defects can lead to the emission of atoms, ions and molecules from the sample. One specific field where laser damage is of serious concern is semiconductor lithography, which is beginning to use light at a wavelength of 157 nm. CaF2 is a candidate material for use in this new generation of lithography. In order to prevent unnecessary damage of optical components, it is necessary to understand the mechanisms for laser damage and the factors that serve to enhance it. In this research, we study various aspects of laser interactions with CaF2, including impurity absorbance and various forms of damage caused by incident laser light. Ultraviolet (UV) laser light at 266 nm with both femtosecond (fs) and nanosecond (ns) pulse widths is used to induce ion and neutral particle emission from cleaved samples of CaF2. The resulting mass spectra show significant differences suggesting that different mechanisms for desorption occur following excitation using the different pulse durations. Following irradiation by ns pulses at 266 nm, multiple single-photon absorption from defect states is likely responsible for ion emission whereas the fs case is driven by a multi-photon absorption process. This idea is further supported by the measurements made of the transmission and reflection of fs laser pulses at 266 nm, the results of which reveal a non-linear absorption process in effect at high incident intensities. In addition, the kinetic energy profiles of desorbed Ca and K contaminant atoms are different indicating that a different mechanism is responsible for their emission as well. Overall, these results show that purity plays a key role in the desorption of atoms from CaF2 when using ns pulses. On the other hand, once the irradiance reaches high levels, like that of the fs case, significant desorption is possible due to multi-photon absorption by the intrinsic material.

Espana, A.; Joly, A.G.; Hess, W.P.; Dickinson, J.T.

2004-01-01T23:59:59.000Z

130

Automating DNA processing  

E-Print Network (OSTI)

Technology is currently available to identify the genetic codes responsible for physical traits and genetic diseases in both plants and animals. Regardless of whether the final goal is medical diagnosis or breeder selection, extensive time and resources must be spent in laboratory research to determine the genetic structure of the relevant organisms. DNA processing is riddled with time intensive laboratory techniques that must be improved or replaced if genotyping large numbers of samples is to be accomplished. This thesis identifies and explains modules in DNA processing and how they can be improved by automation. modules associated with genome mapping are the focus of most of the discussion. A functional biochemistry background is provided so that researchers in automation can be efficiently assimilated to future biochen-fistry/automation projects. The needs of biochemistry researchers at Texas A&M University are specifically addressed. Herein, DNA processing has been defined as a series of discrete sub-processes or process modules in order to aid scheduling of future automation projects. Target process modules (sub-processes with a high probability of automation success) have been identified. In addition, possible automation solutions have been proposed for each target module along with a characterization of fundamental design parameters. Concluding this text is a discussion of procedures in genome mapping that have not been sufficiently automated. The initial focus of this thesis is on short term solutions. However, attention is given to more conceptual solutions accompanied by the biochemistry background necessary to begin developing them. Though systems are proposed to improve the efficiency of many processes, no implementation has been attempted. Design specifications are based on observation of current laboratory techniques and the variance that is typically allowed in relevant process parameters in TAMU laboratories.

Wienen, Michael Jan

1994-01-01T23:59:59.000Z

131

Rapid Damage Assessment Using High-resolution Remote Sensing Imagery: Tools and Techniques  

SciTech Connect

Accurate damage assessment caused by major natural and anthropogenic disasters is becoming critical due to increases in human and economic loss. This increase in loss of life and severe damages can be attributed to growing population, as well as human migration to disaster prone regions of the world. Rapid damage assessment and dissemination of accurate information is critical for creating an effective emergency response. Remote sensing and geographic information systems (GIS) based techniques and tools are important in disaster damage assessment and reporting activities. In this review, we will look into the state of the art techniques in damage assessment using remote sensing and GIS.

Vatsavai, Raju [ORNL; Tuttle, Mark A [ORNL; Bhaduri, Budhendra L [ORNL; Bright, Eddie A [ORNL; Cheriyadat, Anil M [ORNL; Chandola, Varun [ORNL; Graesser, Jordan B [ORNL

2011-01-01T23:59:59.000Z

132

Identifying structural damage from images  

E-Print Network (OSTI)

M. Shinozuka. Re- silient disaster response: Using remotemay facilitate rapid disaster response. Based on the studyimaging for urban disaster response and management, one must

Chen, ZhiQiang

2009-01-01T23:59:59.000Z

133

Unraveling the Fanconi anaemia-DNA repair connection through DNA helicase and translocase activities  

Science Conference Proceedings (OSTI)

How the Fanconi anaemia (FA) chromosome stability pathway functions to cope with interstrand crosslinks and other DNA lesions has been elusive, even after FANCD1 proved to be BRCA2, a partner of Rad51 in homologous recombination. The identification and characterization of two new Fanconi proteins having helicase motifs, FANCM and FANCJ/BRIP1/BACH1, implicates the FANC nuclear core complex as a participant in recognizing or processing damaged DNA, and the BRIP1 helicase as acting independently of this complex.

Thompson, L H

2005-08-16T23:59:59.000Z

134

Shock induced multi-mode damage in depleted uranium  

SciTech Connect

Recent dynamic damage studies on depleted uranium samples have revealed mixed mode failure mechanisms leading to incipient cracking as well as ductile failure processes. Results show that delamination of inclusions upon compression may provide nucleation sites for damage initiation in the form of crack tip production. However, under tension the material propagates cracks in a mixed shear localization and mode-I ductile tearing and cracking. Cracks tips appear to link up through regions of severe, shear dominated plastic flow. Shock recovery experiments were conducted on a 50 mm single stage light gas gun. Serial metallographic sectioning was conducted on the recovered samples to characterize the bulk response of the sample. Experiments show delaminated inclusions due to uniaxial compression without damage propagation. Further results show the propagation of the damage through tensile loading to the incipient state, illustrating ductile processes coupled with mixed mode-I tensile ductile tearing, shear localization, and mode-I cracking in depleted uranium.

Koller, Darcie D [Los Alamos National Laboratory; Cerreta, Ellen K [Los Alamos National Laboratory; Gray, Ill, George T [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

135

How scientists use DNA  

NLE Websites -- All DOE Office Websites (Extended Search)

How scientists use DNA Name: Peter and Edmund Age: NA Location: NA Country: NA Date: NA Question: Dear Scientists, We would like to know some ways that scientists use DNA. For...

136

DNA and Biometrics  

Science Conference Proceedings (OSTI)

... January 17, 2008 Press Release From Mayor Bloomberg's STATE OF THE CITY ADDRESS Efforts towards Portable/Mobile DNA Devices ...

2008-06-25T23:59:59.000Z

137

Photonic Crystal Biosensor with In-Situ Synthesized DNA Probes for Enhanced Sensitivity  

Science Conference Proceedings (OSTI)

We report on a nearly 8-fold increase in multi-hole defect photonic crystal biosensor response by incorporating in-situ synthesis of DNA probes, as compared to the conventional functionalization method employing pre-synthesized DNA probe immobilization.

Hu, Shuren [Vanderbilt University, Nashville] [Vanderbilt University, Nashville; Zhao, Y. [Vanderbilt University, Nashville] [Vanderbilt University, Nashville; Retterer, Scott T [ORNL] [ORNL; Kravchenko, Ivan I [ORNL] [ORNL; Weiss, Sharon [Vanderbilt University, Nashville] [Vanderbilt University, Nashville

2013-01-01T23:59:59.000Z

138

Incorporation of the effect of the composite electric fields of molecular ions as a simulation tool for biological damage due to heavy-ion irradiation  

Science Conference Proceedings (OSTI)

This paper presents a theoretical study of the DNA damage due to the effect of the composite electric fields of H{sub 2}O{sup +} ions produced from the irradiation of a heavy ion onto a cell. A model for atomic and molecular processes in strong electric fields is developed. It is found that the composite electric fields increase the number of events of electron-impact ionization processes. This may promote DNA damage.

Moribayashi, Kengo [Quantum Beam Science Directorate, Japan Atomic Energy Agency, 8-1-7 Umemidai, Kizugawa-City, Kyoto 619-0215 (Japan) and Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe City, Kyoto 610-0394 (Japan)

2011-07-15T23:59:59.000Z

139

Incipient and Progressive Damage in Polyethylene Under Extreme Tensile Conditions  

Science Conference Proceedings (OSTI)

The Dynamic-Tensile-Extrusion (Dyn-Ten-Ext) test was developed at LANL by Gray and coworkers to probe the tensile response of materials at large strains (>1) and high strain-rates (>1000/s) by firing projectiles through a conical die at 300-700 m/s. This technique has recently been applied to various polymers, such as the fluoropolymers PTFE (Teflon) and the chemically similar PCTFE, which respectively exhibited catastrophic fragmentation and distributed dynamic necking. This work details investigations of the Dyn-Ten-Ext response of high density polyethylene, both to failure and sub-critical conditions. At large extrusion ratios ({approx}7.4) and high velocities, such as those previously employed, HDPE catastrophically fragmented in a craze-like manner in the extruded jet. At more modest extrusion ratios and high velocities the specimen extruded a stable jet that ruptured cleanly, and at lower velocities was recovered intact after sustaining substantial internal damage. Thermomechanical finite element simulations showed that the damage corresponded to a locus of shear stress in the presence of hydrostatic tension. X-ray computed tomography corroborated the prediction of a shear damage mechanism by finding the region of partially damaged material to consist of macroscopic shear-mode cracks nearly aligned with the extrusion axis, originating from the location of damage inception.

Furmanski, Jevan [Los Alamos National Laboratory; Brown, Eric [Los Alamos National Laboratory; Trujillo, Carl P. [Los Alamos National Laboratory; Martinez, Daniel Tito [Los Alamos National Laboratory; Gray, George T. III [Los Alamos National Laboratory

2012-06-07T23:59:59.000Z

140

A Protein that Repairs Damage to Cancer Cells | Advanced Photon Source  

NLE Websites -- All DOE Office Websites (Extended Search)

An X-ray Vortex on the Horizon? An X-ray Vortex on the Horizon? How Two Drops Become One Scientists Discover How Nanocluster Contaminants Increase Risk of Spreading Mobile RNA is Poised and Ready Glass Does a Double-Take Science Highlights Archives: 2013 | 2012 | 2011 | 2010 2009 | 2008 | 2007 | 2006 2005 | 2004 | 2003 | 2002 2001 | 2000 | 1998 | Subscribe to APS Science Highlights rss feed A Protein that Repairs Damage to Cancer Cells MAY 5, 2008 Bookmark and Share The ABH2-DNA complex. A team of University of Chicago scientists has shown how two proteins locate and repair damaged genetic material inside cells. Because one of the proteins detects and repairs DNA damage that may result from a certain type of cancer therapy, the researchers raised the possibility of designing a molecule that could interfere with the repair process, making cancer

Note: This page contains sample records for the topic "dna damage response" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Microstructural Characterization of Damage Mechanisms of Graphite ...  

Science Conference Proceedings (OSTI)

Symposium, Nanostructured Materials for Lithium Ion Batteries and for Supercapacitors. Presentation Title, Microstructural Characterization of Damage ...

142

Damage detection by an adaptive real-parameter simulated annealing genetic algorithm  

Science Conference Proceedings (OSTI)

An effective algorithm, which combined an adaptive real-parameter genetic algorithm with simulated annealing, is proposed to detect damage occurrence in beam-type structures. The proposed algorithm uses the displacements of static response and natural ... Keywords: Adaptive mechanism, Damage detection, Genetic algorithm, Optimization, Simulated annealing

Rong-Song He; Shun-Fa Hwang

2006-12-01T23:59:59.000Z

143

Mutations Altering the Interplay between GkDnaC Helicase and DNA Reveal an Insight into Helicase Unwinding  

E-Print Network (OSTI)

Replicative helicases are essential molecular machines that utilize energy derived from NTP hydrolysis to move along nucleic acids and to unwind double-stranded DNA (dsDNA). Our earlier crystal structure of the hexameric helicase from Geobacillus kaustophilus HTA426 (GkDnaC) in complex with single-stranded DNA (ssDNA) suggested several key residues responsible for DNA binding that likely play a role in DNA translocation during the unwinding process. Here, we demonstrated that the unwinding activities of mutants with substitutions at these key residues in GkDnaC are 24-fold higher than that of wildtype protein. We also observed the faster unwinding velocities in these mutants using single-molecule experiments. A partial loss in the interaction of helicase with ssDNA leads to an enhancement in helicase efficiency, while their ATPase activities remain unchanged. In strong contrast, adding accessory proteins (DnaG or DnaI) to GkDnaC helicase alters the ATPase, unwinding efficiency and the unwinding velocity of the helicase. It suggests that the unwinding velocity of helicase

Yu-hua Lo; Shih-wei Liu; Yuh-ju Sun; Hung-wen Lizz; Chwan-deng Hsiao

2011-01-01T23:59:59.000Z

144

Unconventional Ubiquitin Recognition by the Ubiquitin-Binding Motif within the Y-Family DNA Polymerases ? and Rev1  

E-Print Network (OSTI)

Translesion synthesis is an essential cell survival strategy to promote replication after DNA damage. The accumulation of Y family polymerases (pol) ? and Rev1 at the stalled replication machinery is mediated by the ...

DSouza, Sanjay

145

Field Guide: Bearing Damage Mechanisms  

Science Conference Proceedings (OSTI)

Electric Power Research Institute (EPRI) report 1021780, Manual of Bearing Failures and Repair in Power Plant Rotating Equipment, 2011 Update, is a comprehensive document on the subject of fluid film bearing damage modes. This field guide provides a pocket reference based upon the content of that report. ...

2012-11-06T23:59:59.000Z

146

Patterning nanocrystals using DNA  

E-Print Network (OSTI)

nanocrystals. Angewandte Chemie-International Edition, [2]linked by DNA. Angewandte Chemie-International Edition, 39(with proteins. Angewandte Chemie-International Edition, 40(

Williams, Shara Carol

2003-01-01T23:59:59.000Z

147

Molecular dissection of the roles of the SOD genes in mammalian response to low dose irradiation  

SciTech Connect

It has been long recognized that a significant fraction of the radiation-induced genetic damage to cells are caused by secondary oxidative species. Internal cellular defense systems against oxidative stress play significant roles in countering genetic damage induced by ionizing radiation. The role of the detoxifying enzymes may be even more prominent in the case of low-dose, low-LET irradiation, as the majority of genetic damage may be caused by secondary oxidative species. In this study we have attempted to decipher the roles of the superoxide dismutase (SOD) genes, which are responsible for detoxifying the superoxide anions. We used adenovirus vectors to deliver RNA interference (RNAi or siRNA) technology to down-regulate the expression levels of the SOD genes. We have also over-expressed the SOD genes by use of recombinant adenovirus vectors. Cells infected with the vectors were then subjected to low dose ?-irradiation. Total RNA were extracted from the exposed cells and the expression of 9000 genes were profiled by use of cDNA microarrays. The result showed that low dose radiation had clear effects on gene expression in HCT116 cells. Both over-expression and down-regulation of the SOD1 gene can change the expression profiles of sub-groups of genes. Close to 200 of the 9000 genes examined showed over two-fold difference in expression under various conditions. Genes with changed expression pattern belong to many categories that include: early growth response, DNA-repair, ion transport, apoptosis, and cytokine response.

Eric Y. Chuang

2006-08-31T23:59:59.000Z

148

Controlling DNA Methylation  

NLE Websites -- All DOE Office Websites (Extended Search)

Controlling DNA Methylation Though life on earth is composed of a diverse range of organisms, some with many different types of tissues and cells, all these are encoded by a molecule we call DNA. The information required to build a protein is stored in DNA within the cells. Not all the message in the DNA is used in each cell and not all the message is used all the time. During cell differentiation, the cells become dedicated for their specific function which involves selectively activating some genes and repressing others. Gene regulation is an important event in the developmental biology and the biology of various diseases, but a more complex process. Controlling DNA Methylation Though life on earth is composed of a diverse range of organisms, some with many different types of tissues and cells, all these are encoded by a molecule we call DNA. The information required to build a protein is stored in DNA within the cells. Not all the message in the DNA is used in each cell and not all the message is used all the time. During cell differentiation, the cells become dedicated for their specific function which involves selectively activating some genes and repressing others. Gene regulation is an important event in the developmental biology and the biology of various diseases, but a more complex process. In the bacteria there are distinct enzymes while one is capable of cleaving DNA, the other protects DNA by modification. The complementary function provided by the set of enzymes offers a defense mechanism against the phage infection and DNA invasion. The incoming DNA is cleaved sequence specifically by the class of enzymes called restriction endonuclease (REase). The host DNA is protected by the sequence specific action of matching set of enzymes called the DNA methyltransferase (MTase). The control of the relative activities of the REase and MTase is critical because a reduced ratio of MTase/REase activity would lead to cell death via autorestriction. However too high a ratio would fail to provide protection against invading viral DNA. In addition a separate group of proteins capable of controlling R-M proteins have been identified in various restriction-modification (R-M) systems which are called C proteins (Roberts et al., 2003).

149

DNA's Role with Proteins  

NLE Websites -- All DOE Office Websites (Extended Search)

DNA's Role with Proteins DNA's Role with Proteins Name: Hans Location: N/A Country: N/A Date: N/A Question: Is it sure that the most important information of living cells is stored in the DNA? DNA seems to be nothing more than an inventory of useful proteins and a tool to create those proteins. Could it be that more important operational know how of how these proteins interact to build a living organism is actually located in the rest of the cell? So that the rest of the cell is the most important inheritance, whereas DNA merely takes care of the genetic variation? Replies: DNA is the entire library of protein information for an organism. All seven types of protein. It is true that in developmental stages of an organism that the presence and absences of certain proteins and other chemicals generated by proteins will influence what the DNA in a "particular" cell will express. Hence, you can start out with one cell and end up with a complex organism. You may have heard some of this information with the cloning activities that have been going on lately. All the inheritance comes from the DNA, but what parts of the DNA expression may be dictated by the cells special characteristics developed upon specializing. In that way the liver cells will only do "liver" things and the kidney cells will only do "kidney" things, BUT they use the same DNA information to operate, just a different portion of the same DNA that pertains to their particular "job". If you can convince a cell that it does not have a special job anymore, then you can develop the entire organism from this cell with the right signals; this is what cloning techniques have done!

150

Damage  

NLE Websites -- All DOE Office Websites (Extended Search)

in a nuclear reactor in a realistic time frame. XMAT's delivery of fragment ions at fission fragment energies achieves 25 dpahr. Reactor materials experience a range of dose...

151

Application of Nonlinear Elastic Resonance Spectroscopy For Damage Detection In Concrete: An Interesting Story  

SciTech Connect

Nonlinear resonance ultrasound spectroscopy experiments conducted on concrete cores, one chemically and mechanically damaged by alkali-silica reactivity, and one undamaged, show that this material displays highly nonlinear wave behavior, similar to many other damaged materials. They find that the damaged sample responds more nonlinearly, manifested by a larger resonant peak and modulus shift as a function of strain amplitude. The nonlinear response indicates that there is a hysteretic influence in the stress-strain equation of state. Further, as in some other materials, slow dynamics are present. The nonlinear response they observe in concrete is an extremely sensitive indicator of damage. Ultimately, nonlinear wave methods applied to concrete may be used to guide mixing, curing, or other production techniques, in order to develop materials with particular desired qualities such as enhanced strength or chemical resistance, and to be used for damage inspection.

Byers, Loren W. [Los Alamos National Laboratory; Ten Cate, James A. [Los Alamos National Laboratory; Johnson, Paul A. [Los Alamos National Laboratory

2012-06-28T23:59:59.000Z

152

Cellular response to low dose radiation: Role of phosphatidylinositol-3 kinase like kinases  

Science Conference Proceedings (OSTI)

It is increasingly realized that human exposure either to an acute low dose or multiple chronic low doses of low LET radiation has the potential to cause different types of cancer. Therefore, the central theme of research for DOE and NASA is focused on understanding the molecular mechanisms and pathways responsible for the cellular response to low dose radiation which would not only improve the accuracy of estimating health risks but also help in the development of predictive assays for low dose radiation risks associated with tissue degeneration and cancer. The working hypothesis for this proposal is that the cellular mechanisms in terms of DNA damage signaling, repair and cell cycle checkpoint regulation are different for low and high doses of low LET radiation and that the mode of action of phosphatidylinositol-3 kinase like kinases (PIKK: ATM, ATR and DNA-PK) determines the dose dependent cellular responses. The hypothesis will be tested at two levels: (I) Evaluation of the role of ATM, ATR and DNA-PK in cellular response to low and high doses of low LET radiation in simple in vitro human cell systems and (II) Determination of radiation responses in complex cell microenvironments such as human EpiDerm tissue constructs. Cellular responses to low and high doses of low LET radiation will be assessed from the view points of DNA damage signaling, DNA double strand break repair and cell cycle checkpoint regulation by analyzing the activities (i.e. post-translational modifications and kinetics of protein-protein interactions) of the key target proteins for PI-3 kinase like kinases both at the intra-cellular and molecular levels. The proteins chosen for this proposal are placed under three categories: (I) sensors/initiators include ATM ser1981, ATR, 53BP1, gamma-H2AX, MDC1, MRE11, Rad50 and Nbs1; (II) signal transducers include Chk1, Chk2, FANCD2 and SMC1; and (III) effectors include p53, CDC25A and CDC25C. The primary goal of this proposal is to elucidate the differences in cellular defense mechanisms between low and high doses of low LET radiation and to define the radiation doses where the cellular DNA damage signaling and repair mechanisms tend to shift. This information is critically important to address and advance some of the low dose research program objectives of DOE. The results of this proposed study will lead to a better understanding of the mechanisms for the cellular responses to low and high doses of low LET radiation. Further, systematic analysis of the role of PIKK signaling pathways as a function of radiation dose in tissue microenvironment will provide useful mechanistic information for improving the accuracy of radiation risk assessment for low doses. Knowledge of radiation responses in tissue microenvironment is important for the accurate prediction of ionizing radiation risks associated with cancer and tissue degeneration in humans.

Balajee, A.S.; Meador, J.A.; Su, Y.

2011-03-24T23:59:59.000Z

153

DNA | Open Energy Information  

Open Energy Info (EERE)

DNA DNA Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home NEPA Casual Use Determination of NEPA Adequacy Categorical Exclusion Environmental Assessment Environmental Impact Statements Print PDF NEPA-Related Analysis: Determination of NEPA Adequacy (DNA) General Document Collections (28) Documents Regulatory Roadmap NEPA-Related Analysis: Determination of NEPA Adequacy and Land Use Plan Conformance (DNA) placeholder. This query has been included to allow you to use the black arrows in the table header cells to sort the table data. Document # Serial Number Applicant Lead Agency District Office Field Office Development Phase(s) Techniques DOI-BLM-NM-L000-2012-0020-DNA Lightning Dock Geothermal Inc BLM BLM Las Cruces District Office BLM Geothermal/Exploration

154

Keeping track of the damage  

NLE Websites -- All DOE Office Websites (Extended Search)

News Archives: News Archives: 2012 | 2011 | 2010 | 2009 2008 | 2007 | 2006 | 2005 2004 | 2003 | 2002 | 2001 2000 Subscribe to APS News rss feed Keeping track of the damage Scientists resolve long-standing mystery of ion-solid interactions Reprinted with kind permission from ScienceWise - Science Magazine of the Australian National University JANUARY 27, 2009 Bookmark and Share Dr. Patrick Kluth and Claudia Schnohr. Silica (silicon dioxide) is the most abundant mineral in the earth's crust and consequently is a core component in many rocks. It's quite common for such rocks to also contain natural traces of materials like uranium that undergo slow radioactive decay. This radioactivity produces energetic particles that smash through the surrounding silica creating tracks of localized damage in their wake.

155

Field Guide: Turbine Steam Path Damage  

Science Conference Proceedings (OSTI)

Steam path damage, particularly of blades, has long been recognized as a leading cause of steam turbine unavailability for large fossil fuel plants. Damage to steam path components by various mechanisms continues to result in significant economic impact domestically and internationally. Electric Power Research Institute (EPRI) Report TR-108943, Turbine Steam Path Damage: Theory and Practice, Volumes 1 and 2, was prepared to compile the most recent knowledge about turbine steam path damage: identifying th...

2011-12-12T23:59:59.000Z

156

Quantitive DNA Fiber Mapping  

SciTech Connect

Several hybridization-based methods used to delineate single copy or repeated DNA sequences in larger genomic intervals take advantage of the increased resolution and sensitivity of free chromatin, i.e., chromatin released from interphase cell nuclei. Quantitative DNA fiber mapping (QDFM) differs from the majority of these methods in that it applies FISH to purified, clonal DNA molecules which have been bound with at least one end to a solid substrate. The DNA molecules are then stretched by the action of a receding meniscus at the water-air interface resulting in DNA molecules stretched homogeneously to about 2.3 kb/{micro}m. When non-isotopically, multicolor-labeled probes are hybridized to these stretched DNA fibers, their respective binding sites are visualized in the fluorescence microscope, their relative distance can be measured and converted into kilobase pairs (kb). The QDFM technique has found useful applications ranging from the detection and delineation of deletions or overlap between linked clones to the construction of high-resolution physical maps to studies of stalled DNA replication and transcription.

Lu, Chun-Mei; Wang, Mei; Greulich-Bode, Karin M.; Weier, Jingly F.; Weier, Heinz-Ulli G.

2008-01-28T23:59:59.000Z

157

Radiation Damage in Nanostructured Metallic Films  

E-Print Network (OSTI)

High energy neutron and charged particle radiation cause microstructural and mechanical degradation in structural metals and alloys, such as phase segregation, void swelling, embrittlement and creep. Radiation induced damages typically limit nuclear materials to a lifetime of about 40 years. Next generation nuclear reactors require materials that can sustain over 60 - 80 years. Therefore it is of great significance to explore new materials with better radiation resistance, to design metals with favorable microstructures and to investigate their response to radiation. The goals of this thesis are to study the radiation responses of several nanostructured metallic thin film systems, including Ag/Ni multilayers, nanotwinned Ag and nanocrystalline Fe. Such systems obtain high volume fraction of boundaries, which are considered sinks to radiation induced defects. From the viewpoint of nanomechanics, it is of interest to investigate the plastic deformation mechanisms of nanostructured films, which typically show strong size dependence. By controlling the feature size (layer thickness, twin spacing and grain size), it is applicable to picture a deformation mechanism map which also provides prerequisite information for subsequent radiation hardening study. And from the viewpoint of radiation effects, it is of interest to explore the fundamentals of radiation response, to examine the microstructural and mechanical variations of irradiated nanometals and to enrich the design database. More importantly, with the assistance of in situ techniques, it is appealing to examine the defect generation, evolution, annihilation, absorption and interaction with internal interfaces (layer interfaces, twin boundaries and grain boundaries). Moreover, well-designed nanostructures can also verify the speculation that radiation induced defect density and hardening show clear size dependence. The focus of this thesis lies in the radiation response of Ag/Ni multilayers and nanotwinned Ag subjected to charged particles. The radiation effects in irradiated nanograined Fe are also investigated for comparison. Radiation responses in these nanostructured metallic films suggest that immiscible incoherent Ag/Ni multilayers are more resistant to radiation in comparison to their monolithic counterparts. Their mechanical properties and radiation response show strong layer thickness dependence in terms of radiation hardening and defect density. Coherent twin boundaries can interact with stacking fault tetrahedral and remove them effectively. Twin boundaries can actively absorb radiation induced defects and defect clusters resulting in boundary migration. Size dependence is also found in nanograins where fewer defects exhibit in films with smaller grains.

Yu, Kaiyuan

2013-05-01T23:59:59.000Z

158

Ductile damage model with void coalescence  

SciTech Connect

A general model for ductile damage in metals is presented. It includes damage induced by shear stress as well as damage caused by volumetric tension. Spallation is included as a special case. Strain induced damage is also treated. Void nucleation and growth are included and give rise to strain rate effects. Strain rate effects also arise in the model through elastic release wave propagation between damage centers. Underlying physics of the model is the nucleation, growth, and coalescence of voids in a plastically flowing solid. Implementation of the model in hydrocodes is discussed.

Tonks, D.L.

1995-03-01T23:59:59.000Z

159

Chemical damage due to drilling operations  

DOE Green Energy (OSTI)

The drilling of geothermal wells can result in near wellbore damage of both the injection wells and production wells if proper precautions are not taken. Very little specific information on the chemical causes for drilling damage that can directly be applied to the drilling of a geothermal well in a given situation is available in the literature. As part of the present work, the sparse literature references related to the chemical aspects of drilling damage are reviewed. The various sources of chemically induced drilling damages that are related to drilling operations are summarized. Various means of minimizing these chemical damages during and after the drilling of a geothermal well are suggested also.

Vetter, O.J.; Kandarpa, V.

1982-07-14T23:59:59.000Z

160

2010 MICROBIAL STRESS RESPONSE GORDON RESEARCH CONFERENCE, JULY 18-23, 2010  

SciTech Connect

The 2010 Gordon Research Conference on Microbial Stress Responses provides an open and exciting forum for the exchange of scientific discoveries on the remarkable mechanisms used by microbes to survive in nearly every niche on the planet. Understanding these stress responses is critical for our ability to control microbial survival, whether in the context of biotechnology, ecology, or pathogenesis. From its inception in 1994, this conference has traditionally employed a very broad definition of stress in microbial systems. Sessions will cover the major steps of stress responses from signal sensing to transcriptional regulation to the effectors that mediate responses. A wide range of stresses will be represented. Some examples include (but are not limited to) oxidative stress, protein quality control, antibiotic-induced stress and survival, envelope stress, DNA damage, and nutritional stress. The 2010 meeting will also focus on the role of stress responses in microbial communities, applied and environmental microbiology, and microbial development. This conference brings together researchers from both the biological and physical sciences investigating stress responses in medically- and environmentally relevant microbes, as well as model organisms, using cutting-edge techniques. Computational, systems-level, and biophysical approaches to exploring stress responsive circuits will be integrated throughout the sessions alongside the more traditional molecular, physiological, and genetic approaches. The broad range of excellent speakers and topics, together with the intimate and pleasant setting at Mount Holyoke College, provide a fertile ground for the exchange of new ideas and approaches.

Sarah Ades

2011-07-23T23:59:59.000Z

Note: This page contains sample records for the topic "dna damage response" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Dose-dependent transitions in Nrf2-mediated adaptive response and related stress responses to hypochlorous acid in mouse macrophages  

Science Conference Proceedings (OSTI)

Hypochlorous acid (HOCl) is potentially an important source of cellular oxidative stress. Human HOCl exposure can occur from chlorine gas inhalation or from endogenous sources of HOCl, such as respiratory burst by phagocytes. Transcription factor Nrf2 is a key regulator of cellular redox status and serves as a primary source of defense against oxidative stress. We recently demonstrated that HOCl activates Nrf2-mediated antioxidant response in cultured mouse macrophages in a biphasic manner. In an effort to determine whether Nrf2 pathways overlap with other stress pathways, gene expression profiling was performed in RAW 264.7 macrophages exposed to HOCl using whole genome mouse microarrays. Benchmark dose (BMD) analysis on gene expression data revealed that Nrf2-mediated antioxidant response and protein ubiquitination were the most sensitive biological pathways that were activated in response to low concentrations of HOCl (< 0.35 mM). Genes involved in chromatin architecture maintenance and DNA-dependent transcription were also sensitive to very low doses. Moderate concentrations of HOCl (0.35 to 1.4 mM) caused maximal activation of the Nrf2 pathway and innate immune response genes, such as IL-1{beta}, IL-6, IL-10 and chemokines. At even higher concentrations of HOCl (2.8 to 3.5 mM) there was a loss of Nrf2-target gene expression with increased expression of numerous heat shock and histone cluster genes, AP-1-family genes, cFos and Fra1 and DNA damage-inducible Gadd45 genes. These findings confirm an Nrf2-centric mechanism of action of HOCl in mouse macrophages and provide evidence of interactions between Nrf2, inflammatory, and other stress pathways.

Woods, Courtney G. [Division of Computational Biology, Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709 (United States); ExxonMobil Biomedical Sciences Incorporated, Annandale, NJ 08801 (United States); Fu Jingqi; Xue Peng; Hou Yongyong [Division of Translational Biology, Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709 (United States); School of Public Health, China Medical University, Shenyang 110001 (China); Pluta, Linda J.; Yang Longlong; Zhang Qiang; Thomas, Russell S.; Andersen, Melvin E. [Division of Computational Biology, Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709 (United States); Pi Jingbo [Division of Translational Biology, Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709 (United States)], E-mail: jpi@thehamner.org

2009-07-01T23:59:59.000Z

162

Impurity-doped optical shock, detonation and damage location sensor  

DOE Patents (OSTI)

A shock, detonation, and damage location sensor providing continuous fiber-optic means of measuring shock speed and damage location, and could be designed through proper cabling to have virtually any desired crush pressure. The sensor has one or a plurality of parallel multimode optical fibers, or a singlemode fiber core, surrounded by an elongated cladding, doped along their entire length with impurities to fluoresce in response to light at a different wavelength entering one end of the fiber(s). The length of a fiber would be continuously shorted as it is progressively destroyed by a shock wave traveling parallel to its axis. The resulting backscattered and shifted light would eventually enter a detector and be converted into a proportional electrical signals which would be evaluated to determine shock velocity and damage location. The corresponding reduction in output, because of the shortening of the optical fibers, is used as it is received to determine the velocity and position of the shock front as a function of time. As a damage location sensor the sensor fiber cracks along with the structure to which it is mounted. The size of the resulting drop in detector output is indicative of the location of the crack.

Weiss, Jonathan D. (Albuquerque, NM)

1995-01-01T23:59:59.000Z

163

Impurity-doped optical shock, detonation and damage location sensor  

DOE Patents (OSTI)

A shock, detonation, and damage location sensor providing continuous fiber-optic means of measuring shock speed and damage location, and could be designed through proper cabling to have virtually any desired crush pressure. The sensor has one or a plurality of parallel multimode optical fibers, or a singlemode fiber core, surrounded by an elongated cladding, doped along their entire length with impurities to fluoresce in response to light at a different wavelength entering one end of the fiber(s). The length of a fiber would be continuously shorted as it is progressively destroyed by a shock wave traveling parallel to its axis. The resulting backscattered and shifted light would eventually enter a detector and be converted into a proportional electrical signals which would be evaluated to determine shock velocity and damage location. The corresponding reduction in output, because of the shortening of the optical fibers, is used as it is received to determine the velocity and position of the shock front as a function of time. As a damage location sensor the sensor fiber cracks along with the structure to which it is mounted. The size of the resulting drop in detector output is indicative of the location of the crack. 8 figs.

Weiss, J.D.

1995-02-07T23:59:59.000Z

164

Rapid Damage eXplorer (RDX): A Probabilistic Framework for Learning Changes From Bitemporal Images  

SciTech Connect

Recent decade has witnessed major changes on the Earth, for example, deforestation, varying cropping and human settlement patterns, and crippling damages due to disasters. Accurate damage assessment caused by major natural and anthropogenic disasters is becoming critical due to increases in human and economic loss. This increase in loss of life and severe damages can be attributed to the growing population, as well as human migration to the disaster prone regions of the world. Rapid assessment of these changes and dissemination of accurate information is critical for creating an effective emergency response. Change detection using high-resolution satellite images is a primary tool in assessing damages, monitoring biomass and critical infrastructures, and identifying new settlements. In this demo, we present a novel supervised probabilistic framework for identifying changes using very high-resolution multispectral, and bitemporal remote sensing images. Our demo shows that the rapid damage explorer (RDX) system is resilient to registration errors and differing sensor characteristics.

Vatsavai, Raju [ORNL

2012-01-01T23:59:59.000Z

165

Charge transport-mediated recruitment of DNA repair enzymes  

E-Print Network (OSTI)

Damaged or mismatched bases in DNA can be repaired by Base Excision Repair (BER) enzymes that replace the defective base. Although the detailed molecular structures of many BER enzymes are known, how they colocalize to lesions remains unclear. One hypothesis involves charge transport (CT) along DNA [Yavin, {\\it et al.}, PNAS, {\\bf 102}, 3546, (2005)]. In this CT mechanism, electrons are released by recently adsorbed BER enzymes and travel along the DNA. The electrons can scatter (by heterogeneities along the DNA) back to the enzyme, destabilizing and knocking it off the DNA, or, they can be absorbed by nearby lesions and guanine radicals. We develop a stochastic model to describe the electron dynamics, and compute probabilities of electron capture by guanine radicals and repair enzymes. We also calculate first passage times of electron return, and ensemble-average these results over guanine radical distributions. Our statistical results provide the rules that enable us to perform implicit-electron Monte-Carlo simulations of repair enzyme binding and redistribution near lesions. When lesions are electron absorbing, we show that the CT mechanism suppresses wasteful buildup of enzymes along intact portions of the DNA, maximizing enzyme concentration near lesions.

Pak-Wing Fok; Chin-Lin Guo; Tom Chou

2008-11-18T23:59:59.000Z

166

Structural-Damage Detection by Distributed Piezoelectric Transducers and Tuned Electric Circuits  

E-Print Network (OSTI)

A novel technique for damage detection of structures is introduced and discussed. It is based on purely electric measurements of the state variables of an electric network coupled to the main structure through a distributed set of piezoelectric patches. The constitutive parameters of this auxiliary network are optimized to increase the sensitivity of global measurements- as the frequency, response functions relative to selected electric degrees of freedom-with respect to a given class of variations in the structural-mechanical properties. Because the proposed method is based on purely electric input and output measurements, it allows for accurate results in the identification and localization of damages. Use of the electric frequency-response function to identify the mechanical damage leads to nonconvex optimization problems; therefore the proposed sensitivity-enhanced identification procedure becomes computationally efficient if an a priori knowledge about the damage is available.

dell'Isola, F; Vidoli, S

2010-01-01T23:59:59.000Z

167

Structural-Damage Detection by Distributed Piezoelectric Transducers and Tuned Electric Circuits  

E-Print Network (OSTI)

A novel technique for damage detection of structures is introduced and discussed. It is based on purely electric measurements of the state variables of an electric network coupled to the main structure through a distributed set of piezoelectric patches. The constitutive parameters of this auxiliary network are optimized to increase the sensitivity of global measurements- as the frequency, response functions relative to selected electric degrees of freedom-with respect to a given class of variations in the structural-mechanical properties. Because the proposed method is based on purely electric input and output measurements, it allows for accurate results in the identification and localization of damages. Use of the electric frequency-response function to identify the mechanical damage leads to nonconvex optimization problems; therefore the proposed sensitivity-enhanced identification procedure becomes computationally efficient if an a priori knowledge about the damage is available.

F. dell'Isola; F. Vestroni; S. Vidoli

2010-07-13T23:59:59.000Z

168

WEB RESOURCE: Radiation Damage in Materials - TMS  

Science Conference Proceedings (OSTI)

Feb 12, 2007 ... Topic Title: WEB RESOURCE: Radiation Damage in Materials Topic Summary: Allen, Todd. Lecture notes for Univ. of Wisconsin course

169

Detection and Location of Damage on Pipelines  

SciTech Connect

The INEEL has developed and successfully tested a real-time pipeline damage detection and location system. This system uses porous metal resistive traces applied to the pipe to detect and locate damage. The porous metal resistive traces are sprayed along the length of a pipeline. The unique nature and arrangement of the traces allows locating the damage in real time along miles of pipe. This system allows pipeline operators to detect damage when and where it is occurring, and the decision to shut down a transmission pipeline can be made with actual real-time data, instead of conservative estimates from visual inspection above the area.

Karen A. Moore; Robert Carrington; John Richardson

2003-11-01T23:59:59.000Z

170

Schools - Electronic Equipment Damage Due to Lightning  

Science Conference Proceedings (OSTI)

This power quality (PQ) case study presents the investigation of damage to a school's phone equipment, security alarm, and network computer system during a lightning storm.

2003-12-31T23:59:59.000Z

171

Wind Damage in Washington, DC, 1975  

Science Conference Proceedings (OSTI)

... a large region in the Eastern United States was subjected to severe winds. ... Bureau of Standards (NBS) conducted a limited study of wind damage to ...

2011-08-12T23:59:59.000Z

172

Natural Resource Damages Assessment | National Nuclear Security...  

National Nuclear Security Administration (NNSA)

Council Report Calls for Official Natural Resource Damage Assessment for LANL NRDA PreAssessment Screen, January 2010 Factsheet: Los Alamos National Laboratory...

173

NDE, Foreign Object Damage, and Modeling  

Science Conference Proceedings (OSTI)

Oct 10, 2012 ... Ceramic Matrix Composites: NDE, Foreign Object Damage, and .... used in cylindrical liners, pistons, rings and combustion chamber for...

174

Structure of an aprataxin?DNA complex with insights into AOA1 neurodegenerative disease  

SciTech Connect

DNA ligases finalize DNA replication and repair through DNA nick-sealing reactions that can abort to generate cytotoxic 5'-adenylation DNA damage. Aprataxin (Aptx) catalyzes direct reversal of 5'-adenylate adducts to protect genome integrity. Here the structure of a Schizosaccharomyces pombe Aptx-DNA-AMP-Zn{sup 2+} complex reveals active site and DNA interaction clefts formed by fusing a histidine triad (HIT) nucleotide hydrolase with a DNA minor groove-binding C{sub 2}HE zinc finger (Znf). An Aptx helical 'wedge' interrogates the base stack for sensing DNA ends or DNA nicks. The HIT-Znf, the wedge and an '[F/Y]PK' pivot motif cooperate to distort terminal DNA base-pairing and direct 5'-adenylate into the active site pocket. Structural and mutational data support a wedge-pivot-cut HIT-Znf catalytic mechanism for 5'-adenylate adduct recognition and removal and suggest that mutations affecting protein folding, the active site pocket and the pivot motif underlie Aptx dysfunction in the neurodegenerative disorder ataxia with oculomotor apraxia 1 (AOA1).

Tumbale, Percy; Appel, C. Denise; Kraehenbuehl, Rolf; Robertson, Patrick D.; Williams, Jessica S.; Krahn, Joe; Ahel, Ivan; Williams, R. Scott (NIEHS); (Manchester)

2012-09-17T23:59:59.000Z

175

A novel mutation in the putative DNA helicase XH2 is responsible for male-to-female sex reversal associated with an atypical form of the ATR-X syndrome  

Science Conference Proceedings (OSTI)

We describe a pedigree presenting X-linked severe mental retardation associated with multiple congenital abnormalities and 46,XY gonadal dysgenesis, leading in one family member to female gender assignment. Female carriers are unaffected. The dysmorphic features are similar to those described in the {alpha}-thalassemia and mental retardation (ATR-X) syndrome, although there is no clinical evidence of {alpha}-thalassemia in this family. In addition, the family had other clinical features not previously observed in the ATR-X syndrome, including partial optic-nerve atrophy and partial ocular albinism. Mutations in a putative DNA helicase, termed XH2, have been reported to give rise to the ATR-X syndrome. We screened the YCH2 gene for mutations in affected members of the family and identified a 4-bp deletion at an intron/exon boundary that removes an invariant 3{prime} splice-acceptor site. The mutation cosegregates with the syndrome. The genomic deletion causes missplicing of the pre-mRNA, which results in the loss of 8 bp of coding sequence, thereby generating a frameshift and a downstream premature stop codon. Our finding increases the range of clinical features associated with mutations in the XH2 gene. 17 refs., 4 figs., 2 tabs.

Ion, A.; Telvi, L.; Galacteros, F.; McElreavey, K. [Institut Pasteur, Paris (France)] [and others

1996-06-01T23:59:59.000Z

176

DNA microarray analyses reveal a post-irradiation differential time-dependent gene expression profile in yeast cells exposed to X-rays and {gamma}-rays  

SciTech Connect

Ionizing radiation (IR) is the most enigmatic of genotoxic stress inducers in our environment that has been around from the eons of time. IR is generally considered harmful, and has been the subject of numerous studies, mostly looking at the DNA damaging effects in cells and the repair mechanisms therein. Moreover, few studies have focused on large-scale identification of cellular responses to IR, and to this end, we describe here an initial study on the transcriptional responses of the unicellular genome model, yeast (Saccharomyces cerevisiae strain S288C), by cDNA microarray. The effect of two different IR, X-rays, and gamma ({gamma})-rays, was investigated by irradiating the yeast cells cultured in YPD medium with 50 Gy doses of X- and {gamma}-rays, followed by resuspension of the cells in YPD for time-course experiments. The samples were collected for microarray analysis at 20, 40, and 80 min after irradiation. Microarray analysis revealed a time-course transcriptional profile of changed gene expressions. Up-regulated genes belonged to the functional categories mainly related to cell cycle and DNA processing, cell rescue defense and virulence, protein and cell fate, and metabolism (X- and {gamma}-rays). Similarly, for X- and {gamma}-rays, the down-regulated genes belonged to mostly transcription and protein synthesis, cell cycle and DNA processing, control of cellular organization, cell fate, and C-compound and carbohydrate metabolism categories, respectively. This study provides for the first time a snapshot of the genome-wide mRNA expression profiles in X- and {gamma}-ray post-irradiated yeast cells and comparatively interprets/discusses the changed gene functional categories as effects of these two radiations vis-a-vis their energy levels.

Kimura, Shinzo [Laboratory of Environmental Biology, Department of Preventive Medicine, Hokkaido University School of Medicine, Sapporo 060-8638 (Japan); Ishidou, Emi [Human Stress Signal Research Center (HSS), National Institute of Advanced Industrial Science and Technology (AIST) WEST, 16-1 Onogawa, Tsukuba, Ibaraki 305-8569 (Japan); Kurita, Sakiko [Human Stress Signal Research Center (HSS), National Institute of Advanced Industrial Science and Technology (AIST) WEST, 16-1 Onogawa, Tsukuba, Ibaraki 305-8569 (Japan); Suzuki, Yoshiteru [Human Stress Signal Research Center (HSS), National Institute of Advanced Industrial Science and Technology (AIST) WEST, 16-1 Onogawa, Tsukuba, Ibaraki 305-8569 (Japan); Shibato, Junko [Human Stress Signal Research Center (HSS), National Institute of Advanced Industrial Science and Technology (AIST) WEST, 16-1 Onogawa, Tsukuba, Ibaraki 305-8569 (Japan); Rakwal, Randeep [Human Stress Signal Research Center (HSS), National Institute of Advanced Industrial Science and Technology (AIST) WEST, 16-1 Onogawa, Tsukuba, Ibaraki 305-8569 (Japan)]. E-mail: rakwal-68@aist.go.jp; Iwahashi, Hitoshi [Human Stress Signal Research Center (HSS), National Institute of Advanced Industrial Science and Technology (AIST) WEST, 16-1 Onogawa, Tsukuba, Ibaraki 305-8569 (Japan)

2006-07-21T23:59:59.000Z

177

DNA polymerase having modified nucleotide binding site for DNA sequencing  

DOE Patents (OSTI)

A modified gene encoding a modified DNA polymerase is disclosed. The modified polymerase incorporates dideoxynucleotides at least 20-fold better compared to the corresponding deoxynucleotides as compared with the corresponding naturally-occurring DNA polymerase. 6 figs.

Tabor, S.; Richardson, C.

1997-03-25T23:59:59.000Z

178

Hepatitis C virus NS3/4A protein interacts with ATM, impairs DNA repair and enhances sensitivity to ionizing radiation  

Science Conference Proceedings (OSTI)

Hepatitis C virus (HCV) infection is frequently associated with the development of hepatocellular carcinomas and non-Hodgkin's B-cell lymphomas. Nonstructural protein 3 (NS3) of HCV possesses serine protease, nucleoside triphosphatase, and helicase activities, while NS4A functions as a cofactor for the NS3 serine protease. Here, we show that HCV NS3/4A interacts with the ATM (ataxia-telangiectasia mutated), a cellular protein essential for cellular response to irradiation. The expression of NS3/4A caused cytoplasmic translocation of either endogenous or exogenous ATM and delayed dephosphorylation of the phosphorylated ATM and {gamma}-H2AX following ionizing irradiation. As a result, the irradiation-induced {gamma}-H2AX foci persisted longer in the NS3/4A-expressing cells. Furthermore, these cells showed increased comet tail moment in single-cell electrophoresis assay, indicating increased double-strand DNA breaks. The cells harboring an HCV replicon also exhibited cytoplasmic localization of ATM and increased sensitivity to irradiation. These results demonstrate that NS3/4A impairs the efficiency of DNA repair by interacting with ATM and renders the cells more sensitive to DNA damage. This effect may contribute to HCV oncogenesis.

Lai, Chao-Kuen; Jeng, King-Song [Institute of Molecular Biology, Academia Sinica, Taipei, 115, Taiwan (China); Machida, Keigo [Department of Molecular Microbiology and Immunology, University of Southern California, Keck School of Medicine, 2001 Zonal Avenue, Los Angeles, CA 90033 (United States); Cheng, Yi-Sheng [Institute of Molecular Biology, Academia Sinica, Taipei, 115, Taiwan (China); Lai, Michael M.C. [Institute of Molecular Biology, Academia Sinica, Taipei, 115, Taiwan (China); Department of Molecular Microbiology and Immunology, University of Southern California, Keck School of Medicine, 2001 Zonal Avenue, Los Angeles, CA 90033 (United States)], E-mail: michlai@gate.sinica.edu.tw

2008-01-20T23:59:59.000Z

179

Generating DNA code word for DNA computing with realtime PCR  

Science Conference Proceedings (OSTI)

A number of DNA computing models to solve mathematical graph problem such as the Hamiltonian Path Problem (HPP), Traveling Salesman Problem (TSP), and the Shortest Path Problem (SPP) have been proposed and demonstrated. Normally, the DNA sequences used ... Keywords: DNA computing, TaqMan probes, real-time PCR

Muhammad Faiz Mohamed Saaid; Zuwairie Ibrahim; Nor Haniza Sarmin

2008-03-01T23:59:59.000Z

180

Damage from methamphetamine abuse documented  

NLE Websites -- All DOE Office Websites (Extended Search)

Dennis Tartaglia, 212 481-7000, dennist@mbooth.com or Karen McNulty Walsh, 631 344-8350 go to home page Dennis Tartaglia, 212 481-7000, dennist@mbooth.com or Karen McNulty Walsh, 631 344-8350 go to home page 01-16 March 1, 2001 Researchers Document Brain Damage, Reduction in Motor and Cognitive Function from Methamphetamine Abuse "Speed" Shows More Neurotoxic Effects Than Heroin, Cocaine, or Alcohol UPTON, NY -- Two studies by researchers at the U.S. Department of Energy's Brookhaven National Laboratory provide evidence for the first time that abuse of methamphetamine -- the drug commonly known as "speed" -- is associated with physiological changes in two systems of the human brain. The changes are evident even for abusers who have not taken the drug for a year or more. The studies also found that methamphetamine abusers have reduced cognitive and motor functions, even at one year after quitting the drug. The findings appear in the March issue of the American Journal of Psychiatry.

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181

Structural damage identification in wind turbine blades using piezoelectric active sensing with ultrasonic validation  

SciTech Connect

This paper gives a brief overview of a new project at LANL in structural damage identification for wind turbines. This project makes use of modeling capabilities and sensing technology to understand realistic blade loading on large turbine blades, with the goal of developing the technology needed to automatically detect early damage. Several structural health monitoring (SHM) techniques using piezoelectric active materials are being investigated for the development of wireless, low power sensors that interrogate sections of the wind turbine blade using Lamb wave propagation data, frequency response functions (FRFs), and time-series analysis methods. The modeling and sensor research will be compared with extensive experimental testing, including wind tunnel experiments, load and fatigue tests, and ultrasonic scans - on small- to mid-scale turbine blades. Furthermore, this study will investigate the effect of local damage on the global response of the blade by monitoring low-frequency response changes.

Claytor, Thomas N [Los Alamos National Laboratory; Ammerman, Curtt N [Los Alamos National Laboratory; Park, Gyu Hae [Los Alamos National Laboratory; Farinholt, Kevin M [Los Alamos National Laboratory; Farrar, Charles R [Los Alamos National Laboratory; Atterbury, Marie K [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

182

Natural DNA sequencing by synthesis  

E-Print Network (OSTI)

high throughput genome sequencing by natural DNA synthesis.E.E. , et al. , Genome sequencing by natural DNA synthesis.p. 1304-51. Human Genome Sequencing, C.I. , Finishing the

Roller, Eric E.

2011-01-01T23:59:59.000Z

183

A plastic damage approach for confined concrete  

Science Conference Proceedings (OSTI)

There are many situations in which it is necessary to increase the capacity of structures in use. This need maybe either for a change of use or because the structures have suffered some damage or have shown little resistance in case of extreme loads ... Keywords: Concrete, Confinement, Damage, Dilation, Fiber reinforced composites, Plasticity

B. M. Luccioni; V. C. Rougier

2005-10-01T23:59:59.000Z

184

Searching for DNA Lesions: Structural Evidence for Lower- and Higher-Affinity DNA Binding Conformations of Human Alkyladenine DNA Glycosylase  

E-Print Network (OSTI)

To efficiently repair DNA, human alkyladenine DNA glycosylase (AAG) must search the million-fold excess of unmodified DNA bases to find a handful of DNA lesions. Such a search can be facilitated by the ability of glycosylases, ...

Drennan, Catherine L.

185

DNA Profiling Standard Reference Materials  

Science Conference Proceedings (OSTI)

... agreement with the NIST Office of Law Enforcement Standards. ... Related Programs and Projects: SRM 2372 - Human DNA Quantitation Standard. ...

2013-03-15T23:59:59.000Z

186

ASSESSMENT OF INDIVIDUAL VARIATION IN DNA DOUBLE-STRAND BREAK REPAIR CAPACITY IN HUMAN DIPLOID FIBROBLASTS  

NLE Websites -- All DOE Office Websites (Extended Search)

ASSESSMENT OF INDIVIDUAL VARIATION IN DNA DOUBLE-STRAND ASSESSMENT OF INDIVIDUAL VARIATION IN DNA DOUBLE-STRAND BREAK REPAIR CAPACITY IN HUMAN DIPLOID FIBROBLASTS Paul F. Wilson, John M. Hinz, Peter B. Nham, Salustra S. Urbin, Cynthia B. Thomas, Irene M. Jones, and Larry H. Thompson Biosciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA The induction of bi-stranded clustered DNA damage (BCD), which includes direct DNA double-strand breaks (DSBs), is a hallmark of ionizing radiation (IR) exposure. Incorrectly repaired DSBs can cause chromosomal rearrangements and an increased risk of genomic instability and cancer. Because there is polymorphic variation in DNA repair genes and much of this variation is predicted to have a functional impact, healthy people likely vary in their capacity to repair DSBs and other BCD. This project

187

Quantitative, non-invasive imaging of radiation-induced DNA double strand breaks in vivo  

NLE Websites -- All DOE Office Websites (Extended Search)

Quantitative, non-invasive imaging of radiation-induced DNA double strand breaks in vivo Quantitative, non-invasive imaging of radiation-induced DNA double strand breaks in vivo Wenrong Li 1, , Fang Li 1 , Qian Huang 1 , Jingping Shen 1 , Frank Wolf 1 , Yujun He 1 , Xinjian Liu 1 , Y. Angela Hu 1 , Joel. S. Bedford 5 , and Chuan-Yuan Li 1,2,* Departments of 1 Radiation Oncology, 2 Pharmacology, University of Colorado School of Medicine, Aurora, Colorado, USA; 3 Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA DNA double strand breaks are a major form of DNA damage and a key mechanism through which radiotherapy and some chemotherapeutic agents kill cancer cells. Despite its importance, measuring DNA double strand breaks is still a tedious task that is normally carried out by gel electrophoresis or immunofluorescence staining. Here we report a novel approach to image and

188

A new damage testing system for detailed evaluation of damage behavior of bulk KDP and DKDP  

SciTech Connect

We describe a new damage testing approach and instrumentation that provides quantitative measurements of bulk damage performance versus fluence for several frequencies. A major advantage of this method is that it can simultaneously provide direct information on pinpoint density and size, and beam obscuration. This allows for more accurate evaluation of material performance under operational conditions. Protocols for laser conditioning to improve damage performance can also be easily and rapidly evaluated.This damage testing approach has enabled us to perform complex experiments toward probing the fundamental mechanisms of damage initiation and conditioning.

DeMange, P; Negres, R A; Carr, C W; Radousky, H B; Demos, S G

2004-11-17T23:59:59.000Z

189

Oil spill response resources  

E-Print Network (OSTI)

Pollution has become one of the main problems being faced by humanity. Preventing pollution from occurring might be the best idea but is not possible in this fast developing world. So the next best thing to do would be to respond to the pollution source in an effective manner. Oil spills are fast becoming pollution sources that are causing the maximum damage to the environment. This is owing to the compounds that are released and the way oil spreads in both water and land. Preventing the oil spill would be the best option. But once the oil has been spilled, the next best thing to do is to respond to the spill effectively. As a result, time becomes an important factor while responding to an oil spill. Appropriate response to contain and cleanup the spill is required to minimize its potential damage to the ecosystem. Since time and money play a very important role in spill response, it would be a great idea if decisions can be made in such a way that a quick response can be planned. The first part of this study deals with the formation of an 'Oil Spill Resources Handbook', which has information on all the important Oil Spill Contractors. The second and the main part of the study, deals with creating a database in Microsoft Access of the Oil Spill Contractors. The third portion of the study deals with planning an oil spill response using a systems approach.

Muthukrishnan, Shankar

1996-01-01T23:59:59.000Z

190

Underground infrastructure damage for a Chicago scenario  

SciTech Connect

Estimating effects due to an urban IND (improvised nuclear device) on underground structures and underground utilities is a challenging task. Nuclear effects tests performed at the Nevada Test Site (NTS) during the era of nuclear weapons testing provides much information on how underground military structures respond. Transferring this knowledge to answer questions about the urban civilian environment is needed to help plan responses to IND scenarios. Explosions just above the ground surface can only couple a small fraction of the blast energy into an underground shock. The various forms of nuclear radiation have limited penetration into the ground. While the shock transmitted into the ground carries only a small fraction of the blast energy, peak stresses are generally higher and peak ground displacement is lower than in the air blast. While underground military structures are often designed to resist stresses substantially higher than due to the overlying rocks and soils (overburden), civilian structures such as subways and tunnels would generally only need to resist overburden conditions with a suitable safety factor. Just as we expect the buildings themselves to channel and shield air blast above ground, basements and other underground openings as well as changes of geology will channel and shield the underground shock wave. While a weaker shock is expected in an urban environment, small displacements on very close-by faults, and more likely, soils being displaced past building foundations where utility lines enter could readily damaged or disable these services. Immediately near an explosion, the blast can 'liquefy' a saturated soil creating a quicksand-like condition for a period of time. We extrapolate the nuclear effects experience to a Chicago-based scenario. We consider the TARP (Tunnel and Reservoir Project) and subway system and the underground lifeline (electric, gas, water, etc) system and provide guidance for planning this scenario.

Dey, Thomas N [Los Alamos National Laboratory; Bos, Rabdall J [Los Alamos National Laboratory

2011-01-25T23:59:59.000Z

191

DNA waves and water  

E-Print Network (OSTI)

Some bacterial and viral DNA sequences have been found to induce low frequency electromagnetic waves in high aqueous dilutions. This phenomenon appears to be triggered by the ambient electromagnetic background of very low frequency. We discuss this phenomenon in the framework of quantum field theory. A scheme able to account for the observations is proposed. The reported phenomenon could allow to develop highly sensitive detection systems for chronic bacterial and viral infections.

L. Montagnier; J. Aissa; E. Del Giudice; C. Lavallee; A. Tedeschi; G. Vitiello

2010-12-23T23:59:59.000Z

192

The Rothmund-Thomson gene product RECQL4 localizes to the nucleolus in response to oxidative stress  

Science Conference Proceedings (OSTI)

Mutations in the RECQL4 helicase gene have been linked to Rothmund-Thomson syndrome (RTS), which is characterized by poikiloderma, growth deficiency, and a predisposition to cancer. Examination of RECQL4 subcellular localization in live cells demonstrated a nucleoplasmic pattern and, to a lesser degree, staining in nucleoli. Analysis of RECQL4-GFP deletion mutants revealed two nuclear localization regions in the N-terminal region of RECQL4 and a nucleolar localization signal at amino acids 376-386. RECQL4 localization did not change after treatment with the DNA-damaging agents bleomycin, etoposide, UV irradiation and {gamma} irradiation, in contrast to the Bloom and Werner syndrome helicases that relocate to distinct nuclear foci after damage. However, in a significant number of cells exposed to hydrogen peroxide or streptonigrin, RECQL4 accumulated in nucleoli. Using a T7 phage display screen, we determined that RECQL4 interacts with poly(ADP-ribose) polymerase-1 (PARP-1), a nuclear enzyme that promotes genomic integrity through its involvement in DNA repair and signaling pathways. The RECQL4 nucleolar localization was inhibited by pretreatment with a PARP-1 inhibitor. The C-terminal portion of RECQL4 was found to be an in vitro substrate for PARP-1. These results demonstrate changes in the intracellular localization of RECQL4 in response to oxidative stress and identify an interaction between RECQL4 and PARP-1.

Woo, Leslie L. [Department of Pathology, University of Chicago, 5841 South Maryland Ave., MC1089, Chicago, IL 60637 (United States); Futami, Kazunobu [Department of Target Discovery, GeneCare Research Institute, 200 Kajiwara, Kamakura, Kanagawa 247-0063 (Japan); Shimamoto, Akira [Department of Cellular and Molecular Biology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553 (Japan); Furuichi, Yasuhiro [Department of Target Discovery, GeneCare Research Institute, 200 Kajiwara, Kamakura, Kanagawa 247-0063 (Japan); Frank, Karen M. [Department of Pathology, University of Chicago, 5841 South Maryland Ave., MC1089, Chicago, IL 60637 (United States)]. E-mail: kfrank@uchicago.edu

2006-10-15T23:59:59.000Z

193

Carbon Fiber Damage in Accelerator Beam  

E-Print Network (OSTI)

Carbon fibers are commonly used as moving targets in Beam Wire Scanners. Because of their thermomechanical properties they are very resistant to particle beams. Their strength deteriorates with time due to radiation damage and low-cycle thermal fatigue. In case of high intensity beams this process can accelerate and in extreme cases the fiber is damaged during a single scan. In this work a model describing the fiber temperature, thermionic emission and sublimation is discussed. Results are compared with fiber damage test performed on SPS beam in November 2008. In conclusions the limits of Wire Scanner operation on high intensity beams are drawn.

Sapinski, M; Guerrero, A; Koopman, J; Mtral, E

2009-01-01T23:59:59.000Z

194

Seismic damage estimation for buried pipelines - challenges after three decades of progress  

Science Conference Proceedings (OSTI)

This paper analyzes the evolution over the past three decades of seismic damage estimation for buried pipelines and identifies some challenges for future research studies on the subject. The first section of this paper presents a chronological description of the evolution since the mid-1970s of pipeline fragility relations - the most common tool for pipeline damage estimation - and follows with a careful analysis of the use of several ground motion parameters as pipeline damage indicators. In the second section of the paper, four gaps on the subject are identified and proposed as challenges for future research studies. The main conclusion of this work is that enhanced fragility relations must be developed for improving pipeline damage estimation, which must consider relevant parameters that could influence the seismic response of pipelines.

Pineda-porras, Omar Andrey [Los Alamos National Laboratory; Najafi, Mohammand [U. OF TEXAS

2009-01-01T23:59:59.000Z

195

Schools - Lightning Causing Electric Equipment Damage  

Science Conference Proceedings (OSTI)

This power quality (PQ) case study presents the investigation of damage to a school's electronic controls and integrated circuit boards within their fire alarm and clock/bell system when there are lightning storms.

2003-12-31T23:59:59.000Z

196

Dealing with Storm-Damaged Trees  

E-Print Network (OSTI)

Many homeowners need help caring for or removing damaged trees after a natural disaster. This publication explains what a certified arborist is and how to select one. It also cautions against burning debris downed by a storm.

Kirk, Melanie; Taylor, Eric; Foster, C. Darwin

2005-10-25T23:59:59.000Z

197

Dealing with Storm-Damaged Trees (Spanish)  

E-Print Network (OSTI)

Many homeowners need help caring for or removing damaged trees after a natural disaster. This publication explains what a certified arborist is and how to select one. It also cautions against burning debris downed by a storm.

Kirk, Melanie; Taylor, Eric; Foster, C. Darwin

2007-10-08T23:59:59.000Z

198

Tornado Damage Estimation Using Polarimetric Radar  

Science Conference Proceedings (OSTI)

This study investigates the use of tornadic debris signature (TDS) parameters to estimate tornado damage severity using Norman, Oklahoma (KOUN), polarimetric radar data (polarimetric version of the Weather Surveillance Radar-1988 Doppler radar). ...

David J. Bodine; Matthew R. Kumjian; Robert D. Palmer; Pamela L. Heinselman; Alexander V. Ryzhkov

2013-02-01T23:59:59.000Z

199

Laser Damage Precursors in Fused Silica  

Science Conference Proceedings (OSTI)

There is a longstanding, and largely unexplained, correlation between the laser damage susceptibility of optical components and both the surface quality of the optics, and the presence of near surface fractures in an optic. In the present work, a combination of acid leaching, acid etching, and confocal time resolved photoluminescence (CTP) microscopy has been used to study laser damage initiation at indentation sites. The combination of localized polishing and variations in indentation loads allows one to isolate and characterize the laser damage susceptibility of densified, plastically flowed and fractured fused silica. The present results suggest that: (1) laser damage initiation and growth are strongly correlated with fracture surfaces, while densified and plastically flowed material is relatively benign, and (2) fracture events result in the formation of an electronically defective rich surface layer which promotes energy transfer from the optical beam to the glass matrix.

Miller, P; Suratwala, T; Bude, J; Laurence, T A; Shen, N; Steele, W A; Feit, M; Menapace, J; Wong, L

2009-11-11T23:59:59.000Z

200

Thin Film Femtosecond Laser Damage Competition  

SciTech Connect

In order to determine the current status of thin film laser resistance within the private, academic, and government sectors, a damage competition was started at the 2008 Boulder Damage Symposium. This damage competition allows a direct comparison of the current state of the art of high laser resistance coatings since they are tested using the same damage test setup and the same protocol. In 2009 a high reflector coating was selected at a wavelength of 786 nm at normal incidence at a pulse length of 180 femtoseconds. A double blind test assured sample and submitter anonymity so only a summary of the results are presented here. In addition to the laser resistance results, details of deposition processes, coating materials and layer count, and spectral results will also be shared.

Stolz, C J; Ristau, D; Turowski, M; Blaschke, H

2009-11-14T23:59:59.000Z

Note: This page contains sample records for the topic "dna damage response" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Assessing United States hurricane damage under different environmental conditions  

E-Print Network (OSTI)

Hurricane activity between 1979 and 2011 was studied to determine damage statistics under different environmental conditions. Hurricanes cause billions of dollars of damage every year in the United States, but damage ...

Maheras, Anastasia Francis

2012-01-01T23:59:59.000Z

202

Using Landsat to Identify Thunderstorm Damage in Agricultural Regions  

Science Conference Proceedings (OSTI)

During 12 and 18 August 1999, severe thunderstorms produced damaging winds and hail that caused an estimated $50 million in damage to agriculture in west-central Illinois. Landsat-7 imagery was obtained to determine the arealextent of damage and ...

Mace L. Bentley; Thomas L. Mote; Paporn Thebpanya

2002-03-01T23:59:59.000Z

203

Controlled ion implant damage profile for etching  

DOE Patents (OSTI)

This invention pertains to a process for etching a material such as LiNbO{sub 3} by implanting ions having a plurality of different kinetic energies in an area to be etched, and then contacting the ion implanted area with an etchant. The various energies of the ions are selected to produce implant damage substantially uniformly throughout the entire depth of the zone to be etched, thus tailoring the vertical profile of the damaged zone.

Arnold, G.W. Jr.; Ashby, C.I.H.; Brannon, P.J.

1988-08-18T23:59:59.000Z

204

Reference Poster: Turbine Bearing Damage Mechanisms  

Science Conference Proceedings (OSTI)

Damage to turbine and generator bearings accounts for a significant amount of lost generation in the power industry. There are numerous known damage mechanisms affecting these bearings, and as part of EPRIs technology transfer efforts, we have developed a reference poster. This poster provides clear, concise, and visual information for a wide variety of mechanisms and is meant to supplement related EPRI projects. By providing an overview of various issues as well as information on how to ...

2012-10-04T23:59:59.000Z

205

Formation damage in underbalanced drilling operations  

E-Print Network (OSTI)

Formation damage has long been recognized as a potential source of reduced productivity and injectivity in both horizontal and vertical wells. From the moment that the pay zone is being drilled until the well is put on production, a formation is exposed to a series of fluids and operations that can reduce its productive capacity. Any process that causes a loss in the productivity of an oil-, gas-, or water-saturated formation has a damaging effect on the reservoir. These damage mechanisms predominantly fall into three major classifications: mechanical, chemical, and biological. Underbalanced drilling operations involve drilling a portion of the wellbore at fluid pressures less than that of the target formation. This technology has been used to prevent or minimize problems associated with invasive formation damage, which often greatly reduces the productivity of oil and gas reservoirs, mainly in openhole horizontal-well applications. Underbalanced drilling is not a solution for all formation-damage problems. Damage caused by poorly designed and/or executed underbalanced drilling programs can equal or exceed that which may occur with a well-designed conventional overbalanced drilling program. Four techniques are currently available to achieve underbalanced conditions while drilling. These include using lightweight drilling fluids, injecting gas down the drillpipe, injecting gas into a parasite string, and using foam. This study provides an analysis of a number of potential damage mechanisms present when drilling underbalanced. It describes each one and its influence on the productivity of a well. Additionally it presents a general description of the different techniques that can be applied to carry out successful, cost-effective UBD operations, and discusses how these techniques may be used to reduce or eliminate formation damage.

Reyes Serpa, Carlos Alberto

2003-01-01T23:59:59.000Z

206

Properties of DnaB helicase in [lambda] DNA replication  

Science Conference Proceedings (OSTI)

A tailed nicked-circle DNA substrate was used to measure the rapid replication fork (RF) movement catalyzed by E. Coli DnaB helicase and DNA polymerase III holoenzyme (pol III HE) (DnaB-RFs) (30 DnaB hexamers/substrate). The DnaB RFs can efficiently utilize the DNA substrate (60% in 5 min at 30C), and the forks move at a rapid rate (550-780 bp/sec at 30C). The DnaB-RFs have an average maximal processivity of 40,000 nt, and addition of either SSB or primase increase the processivity (150,000 nt + SSB, 70,000-140,000 nt + primase). However, SSB and primase do not affect the rate of fork movement or the amount of substrate utilized in the assay. The [lambda] SS proteins are effective at transferring DnaB onto the DNA substrate (8 DnaB hexamers/substrate). The [lambda] SS proteins do not change the rate of RF movement or the amount of substrate utilized. However, the amount of synthesis measured in the assay is [approximately]2-fold higher in the presence of the [lambda] SS proteins. Therefore, the [lambda] SS proteins increase the processivity of DnaB at the RF (100,000 nt). The [lambda] SS proteins do not appear to play a role in elongation because the processivity of the RF in the presence of SSB and primase is equivalent to the processivity of the [lambda] SS-RFs. [lambda] P protein blocks DnaB helicase activity if added to the RF assay prior to initiation or during elongation. DnaB helicase is more resistant to P inhibition, if the helicase is allowed to bind to the substrate prior to addition of [lambda] P or if primase and rNTPs are included in the assay. These results suggest that the conformation of the RF complex (DNA or nucleoprotein structure) blocks the attack of P on DnaB helicase. The heat shock proteins may play an auxiliary role in mediating the effects of [lambda] P if the concentration of P protein in the cells are high.

Stephens, K.M.

1991-01-01T23:59:59.000Z

207

Reactor Loose Part Damage Assessments on Steam Generator Tube Sheets.  

E-Print Network (OSTI)

??PROCTOR, WILLIAM CYRUS. Reactor Loose Part Damage Assessments on Steam Generator Tube Sheets. (Under the direction of Joseph Michael Doster). Damage from loose parts inside (more)

Proctor, William Cyrus

2010-01-01T23:59:59.000Z

208

ABSTRACT: Ion-Induced Damage Accumulation and Electron-Beam ...  

Science Conference Proceedings (OSTI)

Jun 27, 2007... Ion-Induced Damage Accumulation and Electron-Beam-Enhanced ... damage accumulation in strontium titanate from 1.0 MeV Au irradiation

209

Los Alamos National Laboratory describes storm damage to environmental...  

NLE Websites -- All DOE Office Websites (Extended Search)

Los Alamos National Laboratory describes storm damage Los Alamos National Laboratory describes storm damage to environmental monitoring stations, canyons Stations supporting Santa...

210

Kinetics of Mismatch Formation opposite Lesions by the Replicative DNA Polymerase from Bacteriophage RB69  

Science Conference Proceedings (OSTI)

The fidelity of DNA replication is under constant threat from the formation of lesions within the genome. Oxidation of DNA bases leads to the formation of altered DNA bases such as 8-oxo-7,8-dihydroguanine, commonly called 8-oxoG, and 2-hydroxyadenenine, or 2-OHA. In this work we have examined the incorporation kinetics opposite these two oxidatively derived lesions as well as an abasic site analogue by the replicative DNA polymerase from bacteriophage RB69. We compared the kinetic parameters for both wild type and the low fidelity L561A variant. While nucleotide incorporation rates (k{sub pol}) were generally higher for the variant, the presence of a lesion in the templating position reduced the ability of both the wild-type and variant DNA polymerases to form ternary enzyme-DNA-dNTP complexes. Thus, the L561A substitution does not significantly affect the ability of the RB69 DNA polymerase to recognize damaged DNA; instead, the mutation increases the probability that nucleotide incorporation will occur. We have also solved the crystal structure of the L561A variant forming an 8-oxoG {center_dot} dATP mispair and show that the propensity for forming this mispair depends on an enlarged polymerase active site.

Hogg, Matthew; Rudnicki, Jean; Midkiff, John; Reha-Krantz, Linda; Doubli, Sylvie; Wallace, Susan S. (Alberta); (Vermont)

2010-04-12T23:59:59.000Z

211

Hypersensitivity of human and rodent Fanconianemia (FA) cells to bystander effect-induced DNA damage  

NLE Websites -- All DOE Office Websites (Extended Search)

Hypersensitivity Hypersensitivity o f h uman a nd r odent F anconi a nemia ( FA) c ells t o b ystander effect---induced D NA d amage P.F. Wilson 1,2 , H. Nagasawa 3 , A .C. K ohlgruber 2 , S .S. U rbin 2 , F .A. Bourguet 2 , J .R. Brogan 3 , J .S. Bedford 3 , M .A. Coleman 2 , J.M. Hinz 4 , and J.B. Little 5 1 B iology D epartment/NASA S pace R adiation L aboratory, B rookhaven N ational L aboratory, U pton, N Y 1 1733 2 Biosciences a nd B iotechnology D ivision, L awrence L ivermore N ational L aboratory, L ivermore, C A 9 4551 3 Department o f E nvironmental a nd R adiological H ealth S ciences, C olorado S tate U niversity, F ort C ollins, C O 8 0523 4 School o f M olecular B iosciences, W ashington S tate U niversity, P ullman, W A 9 9164 5 D epartment o f G enetics a nd C omplex D iseases, H arvard S chool o f P ublic H ealth, B oston, M A 0 2115 Fanconi

212

DOE contractors' workshop: Cellular and molecular aspects of radiation induced DNA damage and repair  

SciTech Connect

For four decades the US Department of Energy and its predecessors have been the lead federal agency in supporting radiation biology research. Over the years emphasis in this program has gradually shifted from dose-effect studies on animals to research on the effects of radiations of various qualities on cells and molecules. Mechanistic studies on the action of radiation at the subcellular level are few in number and there is a need for more research in this area if we are to gain a better understanding of how radiation affects living cells. The intent of this workshop was to bring together DOE contractors and grantees who are investigating the effects of radiation at the cellular and molecular levels. The aims were to foster the exchange of information on research projects and experimental results, promote collaborative research efforts, and obtain an overview of research currently supported by the Health Effects Research Division of the Office of Health and Environmental Research. The latter is needed by the Office for program planning purposes. This report on the workshop which took place in Albuquerque, New Mexico on March 10-11, 1987, includes an overview with future research recommendations, extended abstracts of the plenary presentations, shorter abstracts of each poster presentation, a workshop agenda and the names and addresses of the attendees.

Not Available

1987-01-01T23:59:59.000Z

213

Spatiotemporal characterization of ionizing radiation induced DNA damage foci and their relation to chromatin organization  

E-Print Network (OSTI)

beta mobilization promotes chromatin changes that initiatein Rad51 distribution on chromatin during meiosis in malebreaks in the context of chromatin. Nucleic Acids Res M. K.

Costes, Sylvain V

2010-01-01T23:59:59.000Z

214

DNA-based asymmetric catalysis.  

E-Print Network (OSTI)

??The goal of the research described in this thesis was to develop the general concept and methodology of DNA-based asymmetric catalysis, with the aim of (more)

Boersma, Arnold Jacob

2009-01-01T23:59:59.000Z

215

Conserved XPB Core Structure and Motifs for DNA Unwinding:Implications for Pathway Selection of Transcription or ExcisionRepair  

Science Conference Proceedings (OSTI)

The human xeroderma pigmentosum group B (XPB) helicase is essential for transcription, nucleotide excision repair, and TFIIH functional assembly. Here, we determined crystal structures of an Archaeoglobus fulgidus XPB homolog (AfXPB) that characterize two RecA-like XPB helicase domains and discover a DNA damage recognition domain (DRD), a unique RED motif, a flexible thumb motif (ThM), and implied conformational changes within a conserved functional core. RED motif mutations dramatically reduce helicase activity, and the DRD and ThM, which flank the RED motif, appear structurally as well as functionally analogous to the MutS mismatch recognition and DNA polymerase thumb domains. Substrate specificity is altered by DNA damage, such that AfXPB unwinds dsDNA with 3' extensions, but not blunt-ended dsDNA, unless it contains a lesion, as shown for CPD or (6-4) photoproducts. Together, these results provide an unexpected mechanism of DNA unwinding with Implications for XPB damage verification in nucleotide excision repair.

Fan, Li; Arval, Andrew S.; Cooper, Priscilla K.; Iwai, Shigenori; Hanaoka, Fumio; Tainer, John A.

2005-04-01T23:59:59.000Z

216

Identifying a transcriptional signature for cell sensitivity to the cancer chemotherapy agent, BCNU  

E-Print Network (OSTI)

Many organisms have evolved DNA damage response mechanisms to deal with the constant damage to DNA caused by endogenous and exogenous agents. These mechanisms activate cell cycle checkpoints to allow time for DNA repair ...

Valiathan, Chandni Rajan

2011-01-01T23:59:59.000Z

217

Impact of substrate surface scratches on the laser damage resistance of multilayer coatings  

SciTech Connect

Substrate scratches can limit the laser resistance of multilayer mirror coatings on high-peak-power laser systems. To date, the mechanism by which substrate surface defects affect the performance of coating layers under high power laser irradiation is not well defined. In this study, we combine experimental approaches with theoretical simulations to delineate the correlation between laser damage resistance of coating layers and the physical properties of the substrate surface defects including scratches. A focused ion beam technique is used to reveal the morphological evolution of coating layers on surface scratches. Preliminary results show that coating layers initially follow the trench morphology on the substrate surface, and as the thickness increases, gradually overcoat voids and planarize the surface. Simulations of the electrical-field distribution of the defective layers using the finite-difference time-domain (FDTD) method show that field intensification exists mostly near the top surface region of the coating near convex focusing structures. The light intensification could be responsible for the reduced damage threshold. Damage testing under 1064 nm, 3 ns laser irradiation over coating layers on substrates with designed scratches show that damage probability and threshold of the multilayer depend on substrate scratch density and width. Our preliminary results show that damage occurs on the region of the coating where substrate scratches reside and etching of the substrate before coating does not seem to improve the laser damage resistance.

Qiu, S; Wolfe, J; Monterrosa, A; Teslich, N; Feit, M; Pistor, T; Stolz, C

2010-11-03T23:59:59.000Z

218

Determination of thymine glycol residues in irradiated or oxidized DNA by formation of methylglyceric acid  

Science Conference Proceedings (OSTI)

Treatment of DNA solutions with X-irradiation various oxidants including hydrogen peroxide plus ferrous ion, hydrogen peroxide plus copper ion and ascorbate, permanganate, or sonication in the presence of dissolved oxygen all produced varying amounts of thymine glycol residues. After denaturing the DNA with heat, the glycol residues were reduced and labeled at the 6 position with tritium- labeled sodium borohydride. Subsequent reaction with anhydrous methanolic HCl gave a quantitative yield of the methyl ester of methylglyceric acid, which was determined by thin layer chromatography. The method, developed using thymidine as a model, was used to ascertain the requirements for glycol formation in DNA. It was shown that hydroxyl radical generating systems, permanganate, X-irradiation, or sonication in presence of oxygen were required, but hydrogen peroxide in the absence of iron or copper and ascorbate was inactive. Application to determination of DNA damage in vivo is being explored.

Schellenberg, K.A.; Shaeffer, J.

1986-05-01T23:59:59.000Z

219

Damage tracker: a cloud and mobile system for collecting damage information after natural disasters  

Science Conference Proceedings (OSTI)

Tornadoes and other natural disasters frequently cause large amounts of damage to buildings and infrastructure. An important part of learning from these events is assessing key damage-indicators within the affected area. Researchers can analyze these ... Keywords: cloud, geo-tagging, natural disaster, tornado

Chris Hodapp, Matt Robbins, Jeff Gray, Andrew Graettinger

2013-04-01T23:59:59.000Z

220

Demand Response  

NLE Websites -- All DOE Office Websites (Extended Search)

Peak load diagram Demand Response Demand Response (DR) is a set of time-dependent activities that reduce or shift electricity use to improve electric grid reliability, manage...

Note: This page contains sample records for the topic "dna damage response" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Demand Response  

NLE Websites -- All DOE Office Websites (Extended Search)

Peak load diagram Demand Response Demand response (DR) is a set of time-dependent activities that reduce or shift electricity use to improve electric grid reliability, manage...

222

Texas Wildlife Damage Management Service Table of Contents  

E-Print Network (OSTI)

Texas Wildlife Damage Management Service Table of Contents i TEXAS WILDLIFE DAMAGE MANAGMENT.............................................................................................................................. 2 #12;Texas Wildlife Damage Management Service, Texas A&M University System Page 1 TEXAS WILDLIFE-651-2880 karen.s.dulaney@usda.gov #12;Texas Wildlife Damage Management Service, Texas A&M University System Page

Wilkins, Neal

223

Assessing Hail and Freeze Damage to Field Corn and Sorghum  

E-Print Network (OSTI)

When a crop has been damaged by hail, it is important to be able to gauge the extent of the damage, the potential for recovery of the damaged crop, and the actions that might be necessary to maximize the recovery process. This publication tells how to assess hail damage.

Livingston, Stephen

1995-11-30T23:59:59.000Z

224

Application of a model to the evaluation of flood damage  

Science Conference Proceedings (OSTI)

This paper presents the initial results of a common methodology for the evaluation of damage produced by a flood. A model has been developed for flood damage estimation based on a geographic information system (GIS). It could be used by land administration ... Keywords: Damage evaluation, Flood, GIS, Hydraulic modelling, Stage---damage curves

F. Luino; C. G. Cirio; M. Biddoccu; A. Agangi; W. Giulietto; F. Godone; G. Nigrelli

2009-09-01T23:59:59.000Z

225

EFFECT OF CREVICE FORMER ON CORROSION DAMAGE PROPAGATION  

SciTech Connect

The objectives of this report are: (1) To determine the effect of the crevice former on the localized corrosion damage propagation; (2) FOCUS on post initiation stage, crevice propagation and arrest processes; (3) Determine the evolution of damage--severity, shape, location/distribution, damage profile; and (4) Model of crevice corrosion propagation, i.e. the evolution of the crevice corrosion damage profile.

J.H. Payer; U. Landau; X. Shan; A.S. Agarwal

2006-03-01T23:59:59.000Z

226

Radiation-damage calculations with NJOY  

SciTech Connect

Atomic displacement, gas production, transmutation, and nuclear heating can all be calculated with the NJOY nuclear data processing system using evaluated data in ENDF/B format. Using NJOY helps assure consistency between damage cross sections and those used for transport, and NJOY provides convenient interface formats for linking data to application codes. Unique features of the damage calculation include a simple momentum balance treatment for radiative capture and a new model for (n, particle) reactions based on statistical model calculations. Sample results for iron and nickel are given and compared with the results of other methods.

MacFarlane, R.E.; Muir, D.W.; Mann, F.W.

1983-01-01T23:59:59.000Z

227

Quantitative study of oilfield casing damage  

Science Conference Proceedings (OSTI)

Carrying on the analysis to the cause of casing failure based on engineering factors and geological factors, and choosing the improved analytic hierarchy process to have a quantitative study for oilfield of the casing failure, improved the influence ... Keywords: analytical hierarchy process (AHP), casing damage, quantitative analysis

Deng Rui; Zhang Liang; Guo Haimin

2012-09-01T23:59:59.000Z

228

Tornado Damage Survey at Moore, Oklahoma  

Science Conference Proceedings (OSTI)

On 4 May 1999, the Wind Science and Engineering Research Center at Texas Tech University dispatched three survey teams to the Oklahoma City area to conduct a tornado damage survey. The author was the leader of one of the teams whose purpose was ...

Timothy P. Marshall

2002-06-01T23:59:59.000Z

229

Management Responsibilities  

NLE Websites -- All DOE Office Websites (Extended Search)

Management Responsibilities Management Responsibilities Depleted UF6 Management Responsibilities DOE has responsibility for safe and efficient management of approximately 700,000 metric tons of depleted UF6. Organizational Responsibilities In the United States, the U.S. Department of Energy is responsible for managing all the depleted uranium that has been generated by the government and has been declared surplus to national defense needs. In addition, as a result of two memoranda of agreement that have been signed between the DOE and USEC, the DOE has assumed management responsibility for approximately 145,000 metric tons of depleted UF6 that has been or will be generated by USEC. Any additional depleted UF6 that USEC generates will be USEC's responsibility to manage. DOE Management Responsibility

230

Sequence independent amplification of DNA  

DOE Patents (OSTI)

The present invention is a rapid sequence-independent amplification procedure (SIA). Even minute amounts of DNA from various sources can be amplified independent of any sequence requirements of the DNA or any a priori knowledge of any sequence characteristics of the DNA to be amplified. This method allows, for example, the sequence independent amplification of microdissected chromosomal material and the reliable construction of high quality fluorescent in situ hybridization (FISH) probes from YACs or from other sources. These probes can be used to localize YACs on metaphase chromosomes but also--with high efficiency--in interphase nuclei. 25 figs.

Bohlander, S.K.

1998-03-24T23:59:59.000Z

231

Sequence independent amplification of DNA  

DOE Patents (OSTI)

The present invention is a rapid sequence-independent amplification procedure (SIA). Even minute amounts of DNA from various sources can be amplified independent of any sequence requirements of the DNA or any a priori knowledge of any sequence characteristics of the DNA to be amplified. This method allows, for example the sequence independent amplification of microdissected chromosomal material and the reliable construction of high quality fluorescent in situ hybridization (FISH) probes from YACs or from other sources. These probes can be used to localize YACs on metaphase chromosomes but also--with high efficiency--in interphase nuclei.

Bohlander, Stefan K. (Chicago, IL)

1998-01-01T23:59:59.000Z

232

Physical Interactions between Mcm10, DNA, and DNA Polymerase [alpha  

SciTech Connect

Mcm10 is an essential eukaryotic protein required for the initiation and elongation phases of chromosomal replication. Specifically, Mcm10 is required for the association of several replication proteins, including DNA polymerase {alpha} (pol {alpha}), with chromatin. We showed previously that the internal (ID) and C-terminal (CTD) domains of Mcm10 physically interact with both single-stranded (ss) DNA and the catalytic p180 subunit of pol {alpha}. However, the mechanism by which Mcm10 interacts with pol {alpha} on and off DNA is unclear. As a first step toward understanding the structural details for these critical intermolecular interactions, x-ray crystallography and NMR spectroscopy were used to map the binary interfaces between Mcm10-ID, ssDNA, and p180. The crystal structure of an Mcm10-ID {center_dot} ssDNA complex confirmed and extended our previous evidence that ssDNA binds within the oligonucleotide/oligosaccharide binding-fold cleft of Mcm10-ID. We show using NMR chemical shift perturbation and fluorescence spectroscopy that p180 also binds to the OB-fold and that ssDNA and p180 compete for binding to this motif. In addition, we map a minimal Mcm10 binding site on p180 to a small region within the p180 N-terminal domain (residues 286-310). These findings, together with data for DNA and p180 binding to an Mcm10 construct that contains both the ID and CTD, provide the first mechanistic insight into how Mcm10 might use a handoff mechanism to load and stabilize pol {alpha} within the replication fork.

Warren, Eric M.; Huang, Hao; Fanning, Ellen; Chazin, Walter J.; Eichman, Brandt F.; (Vanderbilt)

2009-10-21T23:59:59.000Z

233

UTC Response  

Science Conference Proceedings (OSTI)

... Security Incident response teams, Cyber Security Incident handling ... is the mandatory standards for nuclear power reactor licensees, 10 CFR ...

2013-04-10T23:59:59.000Z

234

When DNA Needs to Stand Up and Be Counted  

NLE Websites -- All DOE Office Websites (Extended Search)

When DNA Needs to Stand Up and Be Counted Print DNA microarrays are small metal, glass, or silicon chips covered with patterns of short single-stranded DNA (ssDNA). These "DNA...

235

Carbon Fiber Damage in Particle Beam  

E-Print Network (OSTI)

Carbon fibers are commonly used as moving targets in beam wire scanners. The heating of the fiber due to energy loss of the particles travelling through is simulated with Geant4. The heating induced by the beam electromagnetic field is estimated with ANSYS. The heat transfer and sublimation processes are modelled. Due to the model nonlinearity, a numerical approach based on discretization of the wire movement is used to solve it for particular beams. Radiation damage to the fiber is estimated with SRIM. The model is tested with available SPS and LEP data and a dedicated damage test on the SPS beam is performed followed by a post-mortem analysis of the wire remnants. Predictions for the LHC beams are made.

Dehning, B; Kroyer, T; Meyer, M; Sapinski, M

2011-01-01T23:59:59.000Z

236

Minimizing formation damage during gravel pack operations  

Science Conference Proceedings (OSTI)

A method is described for minimizing formation damage caused by intrusive fluids prior to a gravel packing operation in loosely consolidated formations penetrated by at least one well. The method comprises: filling the casing of the well with an underbalanced completion fluid; placing within the well a removable packer capable of isolating the space between the casing and the formation from the downhole well pressure; setting through the packer a first tubing suitable for perforating and stabilizing the flow of fluids into the well; perforating the casing; and introducing a blocking agent into the formation via the perforations which agent upon solidification is sufficient to minimize formation damage by avoiding the introduction of formation fluids.

Jennings, A.R. Jr.

1987-05-12T23:59:59.000Z

237

Role of Interleukin-6 in the Radiation Response of Liver Tumors  

SciTech Connect

Purpose: To investigate the role of interleukin (IL)-6 in biological sequelae and tumor regrowth after irradiation for hepatic malignancy, which are critical for the clinical radiation response of liver tumors. Methods and Materials: The Hepa 1-6 murine hepatocellular cancer cell line was used to examine the radiation response by clonogenic assays and tumor growth delay in vivo. After irradiation in a single dose of 6 Gy in vitro or 15 Gy in vivo, biological changes including cell death and tumor regrowth were examined by experimental manipulation of IL-6 signaling. The effects of blocking IL-6 were assessed by cells preincubated in the presence of IL-6-neutralizing antibody for 24 hours or stably transfected with IL-6-silencing vectors. The correlations among tumor responses, IL-6 levels, and myeloid-derived suppressor cells (MDSC) recruitment were examined using animal experiments. Results: Interleukin-6 expression was positively linked to irradiation and radiation resistance, as demonstrated by in vitro and in vivo experiments. Interleukin-6-silencing vectors induced more tumor inhibition and DNA damage after irradiation. When subjects were irradiated with a sublethal dose, the regrowth of irradiated tumors significantly correlated with IL-6 levels and MDSC recruitment in vivo. Furthermore, blocking of IL-6 could overcome irradiation-induced MDSC recruitment and tumor regrowth after treatment. Conclusion: These data demonstrate that IL-6 is important in determining the radiation response of liver tumor cells. Irradiation-induced IL-6 and the subsequent recruitment of MDSC could be responsible for tumor regrowth. Therefore, treatment with concurrent IL-6 inhibition could be a potential therapeutic strategy for increasing the radiation response of tumors.

Chen, Miao-Fen, E-mail: miaofen@adm.cgmh.org.tw [Department of Radiation Oncology, Chang Gung Memorial Hospital, Chiayi, Taiwan (China) [Department of Radiation Oncology, Chang Gung Memorial Hospital, Chiayi, Taiwan (China); College of Medicine, Chang Gung University, Taiwan (China); Hsieh, Ching-Chuan [College of Medicine, Chang Gung University, Taiwan (China) [College of Medicine, Chang Gung University, Taiwan (China); Department of General Surgery, Chang Gung Memorial Hospital, Chiayi, Taiwan (China); Chen, Wen-Cheng [Department of Radiation Oncology, Chang Gung Memorial Hospital, Chiayi, Taiwan (China) [Department of Radiation Oncology, Chang Gung Memorial Hospital, Chiayi, Taiwan (China); College of Medicine, Chang Gung University, Taiwan (China); Lai, Chia-Hsuan [Department of Radiation Oncology, Chang Gung Memorial Hospital, Chiayi, Taiwan (China)] [Department of Radiation Oncology, Chang Gung Memorial Hospital, Chiayi, Taiwan (China)

2012-12-01T23:59:59.000Z

238

Effect of Operational Transients on Boiler Damage  

Science Conference Proceedings (OSTI)

It is increasingly the case that utility systems demand more flexibility in a unit's ability to respond to dispatch requirements, which can create a conflict between maximizing efficient operation and limiting damage accumulation. A boiler can be operated in various cycling modes and can be subjected to planned and unplanned transients associated with load following, minimum load operation, forced cooling, variable pressure operation, increased ramp rates, increased attemperation, over-temperature operat...

2009-03-24T23:59:59.000Z

239

Modeling Coal Seam Damage in Cast Blasting  

SciTech Connect

A discrete element computer program named DMC_BLAST (Distinct Motion Code) has been under development since 1987 for modeling rock blasting (Preece & Taylor, 1989). This program employs explicit time integration and uses spherical or cylindrical elements that are represented as circles in two dimensions. DMC_BLAST calculations compare favorably with data from actual bench blasts (Preece et al, 1993). Coal seam chilling refers to the shattering of a significant portion of the coal leaving unusable fines. It is also refereed to as coal damage. Chilling is caused during a blast by a combination of explosive shock energy and movement of the adjacent rock. Chilling can be minimized by leaving a buffer zone between the bottom of the blastholes and the coal seam or by changing the blast design to decrease the powder factor or by a combination of both. Blast design in coal mine cast blasting is usually a compromise between coal damage and rock fragmentation and movement (heave). In this paper the damage to coal seams from rock movement is examined using the discrete element computer code DMC_BLAST. A rock material strength option has been incorporated into DMC_BLAST by placing bonds/links between the spherical particles used to model the rock. These bonds tie the particles together but can be broken when the tensile, compressive or shear stress in the bond exceeds the defined strength. This capability has been applied to predict coal seam damage, particularly at the toe of a cast blast where drag forces exerted by movement of the overlying rock can adversely effect the top of the coal at the bench face. A simulation of coal mine cast blasting has been performed with special attention being paid to the strength of the coal and its behavior at t he bench face during movement of the overlying material.

Chung, S.H.; Preece, D.S.

1998-11-23T23:59:59.000Z

240

Gas condensate damage in hydraulically fractured wells  

E-Print Network (OSTI)

This project is a research into the effect of gas condensate damage in hydraulically fractured wells. It is the result of a problem encountered in producing a low permeability formation from a well in South Texas owned by the El Paso Production Company. The well was producing from a gas condensate reservoir. Questions were raised about whether flowing bottomhole pressure below dewpoint would be appropriate. Condensate damage in the hydraulic fracture was expected to be of significant effect. In the most recent work done by Adedeji Ayoola Adeyeye, this subject was studied when the effects of reservoir depletion were minimized by introduction of an injector well with fluid composition the same as the original reservoir fluid. He also used an infinite conductivity hydraulic fracture along with a linear model as an adequate analogy. He concluded that the skin due to liquid build-up is not enough to prevent lower flowing bottomhole pressures from producing more gas. This current study investigated the condensate damage at the face of the hydraulic fracture in transient and boundary dominated periods when the effects of reservoir depletion are taken into account. As a first step, simulation of liquid flow into the fracture was performed using a 2D 1-phase simulator in order to help us to better understand the results of gas condensate simulation. Then during the research, gas condensate models with various gas compositions were simulated using a commercial simulator (CMG). The results of this research are a step forward in helping to improve the management of gas condensate reservoirs by understanding the mechanics of liquid build-up. It also provides methodology for quantifying the condensate damage that impairs linear flow of gas into the hydraulic fracture.

Reza, Rostami Ravari

2004-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "dna damage response" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Evaluation of Coal Combustion Product Damage Cases  

Science Conference Proceedings (OSTI)

In 2007, the United States Environmental Protection Agency (USEPA) published an assessment that identified 67 coal combustion product (CCP) management facilities with groundwater or surface water impacts that were categorized as proven or potential damage cases. This report provides further evaluation of these cases, including additional data obtained from power companies and public sources. Volume 1 provides an overview and summary of findings, and Volume 2 provides descriptions of individual cases.

2010-09-03T23:59:59.000Z

242

Evaluation of Coal Combustion Product Damage Cases  

Science Conference Proceedings (OSTI)

In 2007, the United States Environmental Protection Agency (USEPA) published an assessment that identified 67 coal combustion product (CCP) management with groundwater or surface water impacts that were categorized as proven or potential damage cases. This report provides further evaluation of these cases, including additional data obtained from power companies and public sources. Volume 1 provides an overview and summary of findings, and Volume 2 provides descriptions of individual cases.

2010-07-26T23:59:59.000Z

243

Functionalized nanopore-embedded electrodes for rapid DNA sequencing  

E-Print Network (OSTI)

The determination of a patient's DNA sequence can, in principle, reveal an increased risk to fall ill with particular diseases [1,2] and help to design "personalized medicine" [3]. Moreover, statistical studies and comparison of genomes [4] of a large number of individuals are crucial for the analysis of mutations [5] and hereditary diseases, paving the way to preventive medicine [6]. DNA sequencing is, however, currently still a vastly time-consuming and very expensive task [4], consisting of pre-processing steps, the actual sequencing using the Sanger method, and post-processing in the form of data analysis [7]. Here we propose a new approach that relies on functionalized nanopore-embedded electrodes to achieve an unambiguous distinction of the four nucleic acid bases in the DNA sequencing process. This represents a significant improvement over previously studied designs [8,9] which cannot reliably distinguish all four bases of DNA. The transport properties of the setup investigated by us, employing state-of-the-art density functional theory together with the non-equilibrium Green's Function method, leads to current responses that differ by at least one order of magnitude for different bases and can thus provide a much more robust read-out of the base sequence. The implementation of our proposed setup could thus lead to a viable protocol for rapid DNA sequencing with significant consequences for the future of genome related research in particular and health care in general.

Haiying He; Ralph H. Scheicher; Ravindra Pandey; Alexandre Reily Rocha; Stefano Sanvito; Anton Grigoriev; Rajeev Ahuja; Shashi P. Karna

2007-08-29T23:59:59.000Z

244

Fast Neutron Radioactivity and Damage Studies on Materials  

E-Print Network (OSTI)

McClellan, CA 95652 and J. Volk, FNAL, Batavia, Il 60510,current range Wolf and J. Volk, Radiation Damage StudiesJ. Spencer, Z. Wolf and J. Volk, Radiation Damage diation

Spencer, J.; Anderson, S. D.; Wolf, Z.; Volk, J. T.; Pellett, D.; Boussoufi, M.

2007-01-01T23:59:59.000Z

245

Effects of Loading Kinetics on the Shock Response of Polycrystalline Copper  

Science Conference Proceedings (OSTI)

The effects of loading kinetics on the damage evolution in high purity copper samples are summarized as follows: The combination of the energy supplied by the shock impulse (peak stress) and the time spent in it dissipation seem to be responsible for the characteristics of the damage fields. For an increasing coupled parameter of energy*time, more damage was predicted, as well as experimentally observed; As more energy (higher peak stress) was dissipated for longer periods of time (lower decompression rate), the damage fields evolved from early stages of damage, in the form of void nucleation and initial void growth, to the later stages of void coalescence.

Escobedo-Diaz, Juan P. [Los Alamos National Laboratory; Trujillo, Carl P. [Los Alamos National Laboratory; Dennis-Koller, Darcie [Los Alamos National Laboratory; Cerreta, Ellen K. [Los Alamos National Laboratory; Bronkhorst, Curt A. [Los Alamos National Laboratory

2012-06-12T23:59:59.000Z

246

Three Mile Island Plugged Tube Severance: A Study of Damage Mechanisms  

Science Conference Proceedings (OSTI)

During Fall 2001 outages, eddy-current inspections at Three Mile Island Unit 1 and Oconee Nuclear Station Unit 1 revealed wear scars on tubes surrounding previously plugged tubes. In both cases, investigations determined that the plugged tubes had severed and impacted neighboring tubes. As a result, the Nuclear Regulatory Commission (NRC) issued Information Notice 2002-02, which did not require a response but did suggest the industry investigate the generic problem of plugged tubes damaging neighboring t...

2003-05-19T23:59:59.000Z

247

Etoposide Metabolites Enhance DNA Topoisomerase II Cleavage near Leukemia-Associated MLL Translocation Breakpoints  

E-Print Network (OSTI)

ABSTRACT: Chromosomal breakage resulting from stabilization of DNA topoisomerase II covalent complexes by epipodophyllotoxins may play a role in the genesis of leukemia-associated MLL gene translocations. We investigated whether etoposide catechol and quinone metabolites can damage the MLL breakpoint cluster region in a DNA topoisomerase II-dependent manner like the parent drug and the nature of the damage. Cleavage of two DNA substrates containing the normal homologues of five MLL intron 6 translocation breakpoints was examined in vitro upon incubation with human DNA topoisomerase IIR, ATP, and either etoposide, etoposide catechol, or etoposide quinone. Many of the same cleavage sites were induced by etoposide and by its metabolites, but several unique sites were induced by the metabolites. There was a preference for G(-1) among the unique sites, which differs from the parent drug. Cleavage at most sites was greater and more heat-stable in the presence of the metabolites compared to etoposide. The MLL translocation breakpoints contained within the substrates were near strong and/or stable cleavage sites. The metabolites induced more cleavage than etoposide at the same sites within a 40 bp double-stranded oligonucleotide containing two of the translocation breakpoints, confirming the results

Brian D. Lovett; Dirk Strumberg; Ian A. Blair; Shaokun Pang; O Donald; A. Burden; Maureen D. Megonigal; Timothy R. Rebbeck; Neil Osheroff; Yves G. Pommier; Carolyn A. Felix

2000-01-01T23:59:59.000Z

248

Low energy electron stimulated desorption from DNA films dosed with oxygen  

SciTech Connect

Desorption of anions stimulated by 1-18 eV electron impact on self-assembled monolayer (SAM) films of single DNA strands is measured as a function of film temperature (50-250 K). The SAMs, composed of 10 nucleotides, are dosed with O{sub 2}. The OH{sup -} desorption yields increase markedly with exposure to O{sub 2} at 50 K and are further enhanced upon heating. In contrast, the desorption yields of O{sup -}, attributable to dissociative electron attachment to trapped O{sub 2} molecules decrease with heating. Irradiation of the DNA films prior to the deposition of O{sub 2} shows that this surprising increase in OH{sup -} desorption, at elevated temperatures, arises from the reaction of O{sub 2} with damaged DNA sites. These results thus appear to be a manifestation of the so-called 'oxygen fixation' effect, well known in radiobiology.

Mirsaleh-Kohan, Nasrin; Bass, Andrew D.; Cloutier, Pierre; Massey, Sylvain; Sanche, Leon [Groupe en sciences des radiations, Faculte de medecine et des sciences de la sante, Universite de Sherbrooke, Sherbrooke, Quebec J1H 5N4 (Canada)

2012-06-21T23:59:59.000Z

249

Extraction of PCR-amplifiable genomic DNA from Bacillus anthracisspores  

SciTech Connect

Bacterial endospore disruption and nucleic acid extractionresulting in DNA of PCR-amplifiable quality and quantity are not trivial.Responding to the needs of the Hazardous Materials Response Unit (HMRU),Laboratory Division, Federal Bureau of Investigation, protocols weredeveloped to close these gaps. Effectiveness and reproducibility of thetechniques were validated with laboratory grown pure spores of Bacillusanthracis and its close phylogenetic neighbors, and with spiked soils anddamaged samples.

Torok, Tamas

2003-05-19T23:59:59.000Z

250

Characterization of nanoparticle-DNA conjugate and control of DNA conformation on particle surface  

E-Print Network (OSTI)

Nano-science has exploited the hybridization and de-hybridization phenomena of DNA which are one of its fundamental functions. In particular, conjugates of gold nanoparticles and DNA (Au NP-DNA) have been extensively ...

Park, Sunho, 1976-

2009-01-01T23:59:59.000Z

251

Laser-Induced Damage of Calcium Fluoride  

Science Conference Proceedings (OSTI)

Radiation damage of materials has long been of fundamental interest, especially since the growth of laser technology. One such source of damage comes from UV laser light. Laser systems continue to move into shorter wavelength ranges, but unfortunately are limited by the damage threshold of their optical components. For example, semiconductor lithography is making its way into the 157nm range and requires a material that can not only transmit this light (air cannot), but also withstand the highly energetic photons present at this shorter wavelength. CaF2, an alkaline earth halide, is the chosen material for vacuum UV 157 nm excimer radiation. It can transmit light down to 120 nm and is relatively inexpensive. Although it is readily available through natural and synthetic sources, it is often times difficult to find in high purity. Impurities in the crystal can result in occupied states in the band gap that induce photon absorption [2] and ultimately lead to the degradation of the material. In order to predict how well CaF2 will perform under irradiation of short wavelength laser light, one must understand the mechanisms for laser-induced damage. Laser damage is often a two-step process: initial photons create new defects in the lattice and subsequent photons excite these defects. When laser light is incident on a solid surface there is an initial production of electron-hole (e-h) pairs, a heating of free electrons and a generation of local heating around optically absorbing centers [3]. Once this initial excitation converts to the driving energy for nuclear motion, the result is an ejection of atoms, ions and molecules from the surface, known as desorption or ablation [3]. Secondary processes further driving desorption are photoabsorption, successive excitations of self-trapped excitons (STE's) and defects, and ionization of neutrals by incident laser light [3]. The combination of laser-induced desorption and the alterations to the electronic and geometrical structure of the lattice result in defect formation. In the material CaF2 some of these defects take the form of F-centers, an electron trapped at a halogen vacancy [4], and H-centers, a F2- molecular ion at a single lattice site [5]. While the F-centers are stable, the H-centers are transient but can form into aggregates that are stable. There are many different configurations the defects can take based on the relative position of F and H centers in the lattice and this is extensively discussed in literature [1,4,5]. Once these defects have formed they cause further absorption of light, which ultimately induces particle emission and the production of even more defects. Various forms of laser-induced damage of CaF2 have been studied. For example, the mechanism for photon-stimulated desorption (PSD) of F+ from CaF2 (111) is discussed in ref. 6 and the energy threshold, distribution and kinetics governing electron-stimulated desorption (ESD) is investigated in ref. 7. The desorption of neutral Ca and F atoms has also been explored [1]. In this paper I focus on the emission of ions and neutrals from CaF2 under the irradiation of pulsed laser light at 266 nm, in addition to a brief study of its purity and transmittance.

Espana, Aubrey L.; Joly, Alan G.; Hess, Wayne P.; Dickinson, J T.

2004-12-01T23:59:59.000Z

252

Contribution of endogenous and exogenous damage to the total radiation-induced damage in the bacterial spore  

Science Conference Proceedings (OSTI)

Radical scavengers such as polyethylene glycol 4000 and bovine albumin have been used to define the contribution of exogenous and endogenous damage to the total radiation-induced damage in aqueous buffered suspensions of Bacillus pumilus spores. The results indicate that this damage in the bacterial spore is predominantly endogenous.

Jacobs, G.P.; Samuni, A.; Czapski, G.

1980-01-01T23:59:59.000Z

253

Gas condensate damage in hydraulically fractured wells  

E-Print Network (OSTI)

This project is a research into the effect of gas condensate damage in hydraulically fractured wells. It is the result of a problem encountered in producing a low permeability formation from a well in South Texas owned by the El Paso Production Company. The well was producing a gas condensate reservoir and questions were raised about how much drop in flowing bottomhole pressure below dewpoint would be appropriate. Condensate damage in the hydraulic fracture was expected to be of significant effect. Previous attempts to answer these questions have been from the perspective of a radial model. Condensate builds up in the reservoir as the reservoir pressure drops below the dewpoint pressure. As a result, the gas moving to the wellbore becomes leaner. With respect to the study by El-Banbi and McCain, the gas production rate may stabilize, or possibly increase, after the period of initial decline. This is controlled primarily by the condensate saturation near the wellbore. This current work has a totally different approach. The effects of reservoir depletion are minimized by introduction of an injector well with fluid composition the same as the original reservoir fluid. It also assumes an infinite conductivity hydraulic fracture and uses a linear model. During the research, gas condensate simulations were performed using a commercial simulator (CMG). The results of this research are a step forward in helping to improve the management of gas condensate reservoirs by understanding the mechanics of liquid build-up. It also provides methodology for quantifying the condensate damage that impairs linear flow of gas into the hydraulic fracture.

Adeyeye, Adedeji Ayoola

2003-12-01T23:59:59.000Z

254

Ductile damage modeling based on void coalescence and percolation theories  

SciTech Connect

A general model for ductile damage in metals is presented. It includes damage induced by shear stress as well as damage caused by volumetric tension. Spallation is included as a special case. Strain induced damage is also treated. Void nucleation and growth are included, and give rise to strain rate effects. Strain rate effects also arise in the model through elastic release wave propagation between damage centers. The underlying physics of the model is the nucleation, growth, and coalescence of voids in a plastically flowing solid. The model is intended for hydrocode based computer simulation. An experimental program is underway to validate the model.

Tonks, D.L.; Zurek, A.K.; Thissell, W.R.

1995-09-01T23:59:59.000Z

255

Turbine Steam Path Damage: Theory and Practice  

Science Conference Proceedings (OSTI)

Historically, most treatises about steam turbines have concentrated on thermo-dynamics or design. In contrast, the primary focus of this book is on the problems that occur in the turbine steam path. Some of these problems have been long known to the industry, starting as early as A. Stodola's work at the turn of the century in which mechanisms such as solid particle erosion, corrosion and liquid droplet damage were recognized. What we have tried to do here is to provide, in a single, comprehensive refere...

1999-08-18T23:59:59.000Z

256

Proton damage effects on light emitting diodes  

SciTech Connect

We have studied the effects of 16-MeV proton irradiation on the performance of a variety of light emitting diodes (LED's) emitting between 820 and 1300 nm. Total light output and current were measured at room temperature as a function of forward bias prior to and following a sequence of room temperature 16-MeV proton irradiations. Our results indicate that the relative amount of proton-induced degradation from one LED type to another is similar to that observed for neutron and gamma irradiations. More specifically, the most sensitive device is the amphoterically Si-doped GaAs LED which is characterized by a long preirradiation minority carrier lifetime. The most resistant LEDs are the high radiance GaAlAs (820 nm) and InGaAsP (1300 nm) LEDs. As in the case of Si devices, the degradation rate per irradiating particle fluence is significantly greater for proton irradiation of these LEDs than it is for neutron exposure. Neutron damage data presented herein indicate that the ratio of proton-to-neutron degradation rates can be as high as 100. Lifetime-damage constant products for constant current operation are calculated for each LED type and vary from 1.5 x 10/sup -13/ cm/sup 2//p for the InGaAsP LED to 1.1 x 10/sup -10/ cm/sup 2//p for the amphoterically Si-doped GaAs LED.

Rose, B.H.; Barnes, C.E.

1982-03-01T23:59:59.000Z

257

Relative Damaging Ability Of Galactic Cosmic Rays Determined Using Monte Carlo Simulations Of Track Structure  

E-Print Network (OSTI)

The energy deposition characteristics of heavy ions vary substantially compared to those of photons. Many radiation biology studies have compared the damaging effects of different types of radiation to establish relative biological effectiveness among them. These studies are dependent on cell type, biological endpoint, radiation type, dose, and dose rate. The radiation field found in space is much more complicated than that simulated in most experiments, both from a point of dose-rate as well as the highly mixed field of radiative particles encompassing a broad spectrum of energies. To establish better estimates for radiation risks on long-term, deep space missions, the damaging ability of heavy ions requires further understanding. Track structure studies provide significant details about the spatial distribution of energy deposition events in and around the sensitive targets of a mammalian cell. The damage imparted by one heavy ion relative to another can be established by modeling the track structures of ions that make up the galactic cosmic ray (GCR) spectrum and emphasizing biologically relevant target geometries. This research was undertaken to provide a better understanding of the damaging ability of GCR at the cellular level. By comparing ions with equal stopping power values, the differences in track structure will illuminate variations in cell particle traversals and ionization density within cell nuclei. For a cellular target, increased particle traversals, along with increased ionization density, are key identifiers for increased damaging ability. Performing Monte Carlo simulations with the computer code, FLUKA, this research will provide cellular dosimetry data and detail the track structure of the ions. As shown in radiobiology studies, increased ionizations within a cell nucleus generally lead to increased DNA breaks and increased free radical production, resulting in increased carcinogenesis and cell death. The spatial distribution of dose surrounding ions tracks are compared for inter- and intracellular regions. A comparison can be made for many different ions based upon dose and particle fluence across those different regions to predict relative damaging ability. This information can be used to improve estimates for radiation quality and dose equivalent from the space radiation environment.

Cox, Bradley

2011-08-01T23:59:59.000Z

258

Preparation Of Dna-Containing Extract For Pcr Amplification  

NLE Websites -- All DOE Office Websites (Extended Search)

Preparation Of Dna-Containing Extract For Pcr Amplification Preparation Of Dna-Containing Extract For Pcr Amplification The method may provide a DNA-containing extract sufficiently...

259

Rapid Relief: A Prefabricated Response  

E-Print Network (OSTI)

As illustrated by the aftermath of disasters such as Hurricanes Katrina, Ike and Sandy, the disaster response phases do not entail an effective or standard procedure for rebuilding damaged and destroyed residences. I propose the implementation of prefabricated construction techniques with the utilization of Building Information Modeling (BIM) technology into the rebuild phase that would proceed throughout the entire duration of disaster recovery, starting with the immediate respondents. My research provides a variation of sample projects ranging from previous buildings erected in response to a hurricane to prefabricated projects that are able to be assembled rather than constructed. With these projects, I am able to analyze their construction methods in order to determine an adequate proposal for disaster reconstruction. My belief is that a standardized procedure would allow for an expedited response time, a structured addressing of the needs of the affected residents, and a sufficient start to the reconstruction of the victims futures.

Gohmert, Brent Cole

2013-05-01T23:59:59.000Z

260

Incorporation of the effect of the composite electric fields of molecular ions as a simulation tool for biological damage due to heavy ion irradiation II  

SciTech Connect

This paper presents a theoretical study of the DNA damage due to the effect of the composite electric fields of H{sub 2}O{sup +} ions produced from the irradiation of a heavy ion onto a cell. It is found that a much larger number of electrons, which are produced from electron impact ionization, is trapped near the track of an incident ion in the case of C{sup 6+} ion irradiation with the energy of 3 MeV/u than that of proton irradiation. Therefore, the irradiation of carbon ions may produce a larger number of cluster DNA damage than that in the irradiation of protons. This may lead to the understanding of relative biological effectiveness (RBE).

Moribayashi, Kengo [Quantum Beam Science Directorate, Japan Atomic Energy Agency, 8-1-7, Umemidai, Kizugawa-city, 619-0215 (Japan) and Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe City, 610-0394 (Japan)

2012-07-11T23:59:59.000Z

Note: This page contains sample records for the topic "dna damage response" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Silencing and recombination in yeast ribosomal DNA  

E-Print Network (OSTI)

A bioinformatic and laboratory investigation into S. cerevisiae's system for the maintenance and homogenization of rDNA. Eliminating mutations and heterogeneity in rDNA repeats is necessary evolutionarily, but harmful to ...

O'Kelly, Michael J. T

2008-01-01T23:59:59.000Z

262

Exelon response  

Energy.gov (U.S. Department of Energy (DOE))

This letter constitutes the response of Exelon Generation Company, LLC and its operating unit,Exelon Nuclear Partners, to the Department of Energysrequest for comments and information (July 27,...

263

Low-cost, Rapid DNA Sequencing Technique  

Sequencing DNA is crucial for future breakthroughs in biological and biomedical research. Until now, ... The nucleic acid strand transport

264

Topics and Techniques in Forensic DNA Analysis  

Science Conference Proceedings (OSTI)

... Topics and Techniques for Forensic DNA Analysis NYC OCME Dept of Forensic Biology ... NIST Human Identity Project Leader (1999-present) ...

2012-04-17T23:59:59.000Z

265

Quantum Dot Fluorescence Lifetime Engineering with DNA ...  

Science Conference Proceedings (OSTI)

Quantum Dot Fluorescence Lifetime Engineering with DNA Origami ... such as metal nanoparticles and semiconductor quantum dots is challenging ...

266

Amplification of chromosomal DNA in situ  

DOE Patents (OSTI)

Amplification of chromosomal DNA in situ to increase the amount of DNA associated with a chromosome or chromosome region is described. The amplification of chromosomal DNA in situ provides for the synthesis of Fluorescence in situ Hybridization (FISH) painting probes from single dissected chromosome fragments, the production of cDNA libraries from low copy mRNAs and improved in Comparative Genomic Hybridization (CGH) procedures.

Christian, Allen T. (Tracy, CA); Coleman, Matthew A. (Livermore, CA); Tucker, James D. (Livermore, CA)

2002-01-01T23:59:59.000Z

267

Magnetic tweezers to study DNA motors  

E-Print Network (OSTI)

Magnetic tweezers to study DNA motors Maria Mañosas Ritort lab UB Barcelona Croquette-Bensimon lab ENS France #12;· Introduction to MT (magnetic tweezers) · Applications: 1. Tracking DNA motors: (i) Helicases (ii) Annealing motor 2. Studying a multiprotein system: DNA replication Outline #12;· Atomic force

Ritort, Felix

268

Data hiding methods based upon DNA sequences  

Science Conference Proceedings (OSTI)

In this paper, three data hiding methods are proposed, based upon properties of DNA sequences. It is highlighted that DNA sequences possess some interesting properties which can be utilized to hide data. These three methods are: the Insertion Method, ... Keywords: Complementary pair, DNA, Data hiding, Data recovery

H. J. Shiu; K. L. Ng; J. F. Fang; R. C. T. Lee; C. H. Huang

2010-06-01T23:59:59.000Z

269

Probe and method for DNA detection  

SciTech Connect

A hybridization probe containing two linear strands of DNA lights up upon hybridization to a target DNA using silver nanoclusters that have been templated onto one of the DNA strands. Hybridization induces proximity between the nanoclusters on one strand and an overhang on the other strand, which results in enhanced fluorescence emission from the nanoclusters.

Yeh, Hsin-Chih; Werner, James Henry; Sharma, Jaswinder Kumar; Martinez, Jennifer Suzanne

2013-07-02T23:59:59.000Z

270

Radiation Damage in Polarized Ammonia Solids  

E-Print Network (OSTI)

Solid NH3 and ND3 provide a highly polarizable, radiation resistant source of polarized protons and deuterons and have been used extensively in high luminosity experiments investigating the spin structure of the nucleon. Over the past twenty years, the UVA polarized target group has been instrumental in producing and polarizing much of the material used in these studies, and many practical considerations have been learned in this time. In this discussion, we analyze the polarization performance of the solid ammonia targets used during the recent JLab Eg4 run. Topics include the rate of polarization decay with accumulated charge, the annealing procedure for radiation damaged targets to recover polarization, and the radiation induced change in optimum microwave frequency used to polarize the sample. We also discuss the success we have had in implementing frequency modulation of the polarizing microwave frequency.

K. Slifer

2007-11-28T23:59:59.000Z

271

Design, optimization and predictions of a coupled model of the cell cycle, circadian clock, DNA repair system, irinotecan metabolism and exposure control under temporal logic constraints  

Science Conference Proceedings (OSTI)

In systems biology, the number of available models of cellular processes has increased rapidly, but re-using models in different contexts or for different questions remains a challenging issue. In this paper, we study the coupling of different models ... Keywords: Cell cycle, Constraint solving, DNA damage, Irinotecan, Model checking, Model coupling, Parameter learning, Temporal logic

Elisabetta De Maria; Franois Fages; Aurlien Rizk; Sylvain Soliman

2011-05-01T23:59:59.000Z

272

Binary electrokinetic separation of target DNA from background DNA primers.  

Science Conference Proceedings (OSTI)

This report contains the summary of LDRD project 91312, titled ''Binary Electrokinetic Separation of Target DNA from Background DNA Primers''. This work is the first product of a collaboration with Columbia University and the Northeast BioDefense Center of Excellence. In conjunction with Ian Lipkin's lab, we are developing a technique to reduce false positive events, due to the detection of unhybridized reporter molecules, in a sensitive and multiplexed detection scheme for nucleic acids developed by the Lipkin lab. This is the most significant problem in the operation of their capability. As they are developing the tools for rapidly detecting the entire panel of hemorrhagic fevers this technology will immediately serve an important national need. The goal of this work was to attempt to separate nucleic acid from a preprocessed sample. We demonstrated the preconcentration of kilobase-pair length double-stranded DNA targets, and observed little preconcentration of 60 base-pair length single-stranded DNA probes. These objectives were accomplished in microdevice formats that are compatible with larger detection systems for sample pre-processing. Combined with Columbia's expertise, this technology would enable a unique, fast, and potentially compact method for detecting/identifying genetically-modified organisms and multiplexed rapid nucleic acid identification. Another competing approach is the DARPA funded IRIS Pharmaceutical TIGER platform which requires many hours for operation, and an 800k$ piece of equipment that fills a room. The Columbia/SNL system could provide a result in 30 minutes, at the cost of a few thousand dollars for the platform, and would be the size of a shoebox or smaller.

James, Conrad D.; Derzon, Mark Steven

2005-10-01T23:59:59.000Z

273

Evaluation of moisture damage within asphalt concrete mixes  

E-Print Network (OSTI)

Pavements are a major part of the infrastructure in the United States. Moisture damage of these pavements is a significant problem. To predict and prevent this kind of moisture damage a great deal of research has been performed on this issue in past. This study validates an analytical approach based on surface energy aimed at assessing moisture damage. Two types of bitumen and three aggregates are evaluated in the study. The two types of bitumen represent very different chemical extremes and the three aggregates (a limestone, siliceous gravel, and granite) represent a considerable range in mineralogy. Moisture damage was monitered as a change in dynamic modulus with load cycles. The analysis demonstrates the need to consider mixture compliance as well as bond energy in order to predict moisture damage. Mixtures with the two types of bitumen and each aggregate with and without hydrated lime were evaluated. The hydrated lime substantially improved the resistance of the mixture to moisture damage.

Shah, Brij D.

2003-08-01T23:59:59.000Z

274

7th International Workshop on Microbeam Probes of Cellular Radiation Response  

Science Conference Proceedings (OSTI)

The extended abstracts that follow present a summary of the Proceedings of the 7th International Workshop: Microbeam Probes of Cellular Radiation Response, held at Columbia Universitys Kellogg Center in New York City on March 1517, 2006. These International Workshops on Microbeam Probes of Cellular Radiation Response have been held regularly since 1993 (15). Since the first workshop, there has been a rapid growth (see Fig. 1) in the number of centers developing microbeams for radiobiological research, and worldwide there are currently about 30 microbeams in operation or under development. Single-cell/single-particle microbeam systems can deliver beams of different ionizing radiations with a spatial resolution of a few micrometers down to a few tenths of a micrometer. Microbeams can be used to addressquestions relating to the effects of low doses of radiation (a single radiation track traversing a cell or group of cells), to probe subcellular targets (e.g. nucleus or cytoplasm), and to address questions regarding the propagation of information about DNA damage (for example, the radiation-induced bystander effect). Much of the recent research using microbeams has been to study low-dose effects and non-targeted responses such as bystander effects, genomic instability and adaptive responses. This Workshop provided a forum to assess the current state of microbeam technology and current biological applications and to discuss future directions for development, both technological and biological. Over 100 participants reviewed the current state of microbeam research worldwide and reported on new technological developments in the fields of both physics and biology.

Brenner, David J.

2009-07-21T23:59:59.000Z

275

Brief Review of Building Damage by The 2011 Tohoku Japan ...  

Science Conference Proceedings (OSTI)

... the coast of Japan, damages of many buildings and residential land by ... BRI) and the National Institute for Land & Infrastructure Management (NILIM ...

2013-02-19T23:59:59.000Z

276

MEASUREMENT OF MATERIAL PROPERTIES OF DAMAGED ENERGETIC MATERIALS  

SciTech Connect

We recently conducted damaged experiments on three explosives (mechanical damage on LX-04 and thermal experiments on HPP and PBXN-9) and characterized the effect of damage on some material properties. The MTS equipment was used to apply compressive cycling to LX-04 pressed parts and the results showed that older LX-04 parts became mechanically weaker than newer parts. After repeated compressive cycling for over 20,000 times, older LX-04 parts failed but newer LX-04 parts survived. Thermal insults were applied to PBXN-9 and HPP at 180 C and 200 C, respectively in unconfined conditions for several hours. The thermally-damaged HPP sample suffered 12.0% weight losses and a volume expansion of 20% was observed. Porosity of the damaged HPP increased to 25% after thermal exposure, which led to higher gas permeability. Burn rates of damaged PBXN-9 were 2 orders of magnitude higher than those of pristine samples but burn rates of damaged HPP were only slightly higher than those of pristine HPP. Small-scale safety tests (impact, friction, and spark) showed no significant sensitization when the damaged samples were tested at room temperature. Gas permeation measurements showed that gas permeability in damaged materials was several orders of magnitude higher than that in pristine materials. In-situ measurements of gas permeability at high temperatures were made on HPP samples and the results showed that the gas permeability increased by 3 to 4 orders of magnitude.

Hsu, P C; Hust, G; Dehaven, M; Chidester, S; Glascoe, L; Hoffman, M; Maienschein, J L

2010-03-10T23:59:59.000Z

277

ORNL analysis predicts losses from extreme weather damage could...  

NLE Websites -- All DOE Office Websites (Extended Search)

ORNL analysis predicts losses from extreme weather damage could double by 2050 Researcher tackles unprecedented county-by-county economic loss forecast Research in impacts,...

278

Understanding How Damages Are Determined in Patent Litigation  

Science Conference Proceedings (OSTI)

Understanding How Damages Are Determined in Patent Litigation. Arnold B. Silverman. The owner of a U.S. patent has the right to prevent others from making ,...

279

COURSE NOTES: Radiation Damage in Metals (NEEP 541)  

Science Conference Proceedings (OSTI)

Feb 10, 2007 ... "Radiation Damage in Metals (NEEP 541)." Department of Engineering Physics. Fall 2005. University of Wisconsin-Madison. Launch Site

280

Neutronics and radiation damage calculations for fusion reactors  

DOE Green Energy (OSTI)

Some of the neutronics calculations that have been carried out at the Oak Ridge National Laboratory to assess radiation damage problems in fusion reactors are presented and discussed.

Alsmiller, R.G. Jr.; Gabriel, T.A.; Santoro, R.T.

1977-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "dna damage response" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Identification of Damage Modes in Ceramic Matrix Composites ...  

Science Conference Proceedings (OSTI)

Analysis and Modeling of Foreign Object Damage (FOD) in Ceramic Matrix ... and Microstructure of Alumina Composites for Energy Efficient Sliding Systems.

282

A Rate-Theory Approach to Irradiation Damage Modeling with ...  

Science Conference Proceedings (OSTI)

Symposium, Materials and Fuels for the Current and Advanced Nuclear Reactors II. Presentation Title, A Rate-Theory Approach to Irradiation Damage Modeling...

283

Lumber-Wood Products - ASDs and Lighting Ballasts Damage  

Science Conference Proceedings (OSTI)

This power quality (PQ) case study presents the investigation of equipment damage to adjustable speed drives (ASDs) and lighting ballasts at a hardwood floor manufacturing facility.

2003-12-31T23:59:59.000Z

284

Fleet DNA Project (Fact Sheet)  

SciTech Connect

The Fleet DNA Project - designed by the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) in partnership with Oak Ridge National Laboratory - aims to accelerate the evolution of advanced vehicle development and support the strategic deployment of market-ready technologies that reduce costs, fuel consumption, and emissions. At the heart of the Fleet DNA Project is a clearinghouse of medium- and heavy-duty commercial fleet transportation data for optimizing the design of advanced vehicle technologies or for selecting a given technology to invest in. An easy-to-access online database will help vehicle manufacturers and fleets understand the broad operational range for many of today's commercial vehicle vocations.

Not Available

2012-10-01T23:59:59.000Z

285

Human Genome Research: Decoding DNA  

NLE Websites -- All DOE Office Websites (Extended Search)

Human Genome Research: Decoding DNA Human Genome Research: Decoding DNA Resources with Additional Information Charles DeLisi As head of DOE's Office of Health and Environmental Research, Charles DeLisi played a pivotal role in proposing and initiating the Human Genome Program in 1986. The U.S. Department of Energy (DOE) has historically been active in supporting human genome research. On September 10, 2003, Secretary of Energy Spencer Abraham presented the Secretary's Gold Award to Aristides Patrinos and Francis Collins for their leadership of the government's Human Genome Project. At DOE's Office of Science, Dr. Patrinos is the Associate Director for Biological and Environmental Research. He has been a researcher at the department's Oak Ridge National Laboratory and Brookhaven National Laboratory.

286

Channel plate for DNA sequencing  

DOE Patents (OSTI)

This invention is a channel plate that facilitates data compaction in DNA sequencing. The channel plate has a length, a width and a thickness, and further has a plurality of channels that are parallel. Each channel has a depth partially through the thickness of the channel plate. Additionally an interface edge permits electrical communication across an interface through a buffer to a deposition membrane surface.

Douthart, Richard J. (Richland, WA); Crowell, Shannon L. (Eltopia, WA)

1998-01-01T23:59:59.000Z

287

Channel plate for DNA sequencing  

DOE Patents (OSTI)

This invention is a channel plate that facilitates data compaction in DNA sequencing. The channel plate has a length, a width and a thickness, and further has a plurality of channels that are parallel. Each channel has a depth partially through the thickness of the channel plate. Additionally an interface edge permits electrical communication across an interface through a buffer to a deposition membrane surface. 15 figs.

Douthart, R.J.; Crowell, S.L.

1998-01-13T23:59:59.000Z

288

An analysis of the kinetics of thermal damage and movement of damage front in laser irradiated egg white  

E-Print Network (OSTI)

Some of the major applications of laser surgery involve the photocoagulation of diseased tissue, with minimal or no damage to the surrounding healthy tissue. There is a growing need for a model for the quantification of thermal damage. The models presently available in the literature assume biological tissue to be composed of a single component having a single rate of damage. But recent studies have shown that a distribution of rate parameters rather than a single rate parameter, best describes the process of thermal coagulation. This study assumes tissue to be composed of two or more components, having different rates of damage. The results of this model are then used to find an effective rate of damage for a single rate model which would yield the same end concentrations as the multi rate model. Results indicate that the difference between the single rate and the multi rate predictions is highly predominant for relatively lower power settings, for the biokinetic coefficient values used in this research. As the power is increased, a single rate model effectively describes a multi rate model, in the prediction of damage and movement of damage front. The movement of damage front was also studied experimentally using Digital Image Processing techniques. The damage model predicted by this study qualitatively follows the theoretical models available in the literature.

Azeemi, Aamer Amjed

1993-01-01T23:59:59.000Z

289

Chemistry of radiation damage to wire chambers  

SciTech Connect

Proportional counters are used to study aspects of radiation damage to wire chambers (wire aging). Principles of low-pressure, rf plasma chemistry are used to predict the plasma chemistry in electron avalanches (1 atm, dc). (1) Aging is studied in CF{sub 4}/iC{sub 4}H{sub 10} gas mixtures. Wire deposits are analyzed by Auger electron spectroscopy. An apparent cathode aging process resulting in loss of gain rather than in a self-sustained current is observed in CF{sub 4}-rich gases. A four-part model considering plasma polymerization of the hydrocarbon, etching of wire deposits by CF{sub 4}, acceleration of deposition processes in strongly etching environments, and reactivity of the wire surface is developed to understand anode wire aging in CF{sub 4}/iC{sub 4}H{sub 10} gases. Practical guidelines suggested by the model are discussed. (2) Data are presented to suggest that trace amounts of Freons do not affect aging rates in either dimethyl ether or Ar/C{sub 2}H{sub 6}. Apparent loss of gain is explained by attachment of primary electrons to a continuously increasing concentration of Freon 11 (CCl{sub 3}F) in the counter gas. An increase in the concentration of Freon 11 in dimethyl ether is caused by a distillation process in the gas supply bottle and is a natural consequence of the unequal volatilities of the two compounds.

Wise, J.

1992-08-01T23:59:59.000Z

290

Micro-crack Damage Evolution of Fracturing Rock Chaotic Characteristics  

Science Conference Proceedings (OSTI)

Chaotic theory and bifurcation of modern nonlinear science were used to study the evolution of micro-cracks under the hydraulic fracturing of the rock mass characteristics, the tensor damage variable which described the chao evolution of micro-cracks ... Keywords: chaos theory, bifurcation theory, damage evolution

Zhaowan Chun; Wang Tingting

2010-06-01T23:59:59.000Z

291

Detection of Storm Damage Tracks with EOS Data  

Science Conference Proceedings (OSTI)

The damage surveys conducted by the NWS in the aftermath of a reported tornadic event are used to document the location of the tornado ground damage track (pathlength and width) and an estimation of the tornado intensity. This study explores the ...

Gary J. Jedlovec; Udaysankar Nair; Stephanie L. Haines

2006-06-01T23:59:59.000Z

292

AFM CHARACTERIZATION OF LASER INDUCED DAMAGE ON CDZNTE CRYSTAL SURFACES  

Science Conference Proceedings (OSTI)

Semi-conducting CdZnTe (or CZT) crystals can be used in a variety of detector-type applications. CZT shows great promise for use as a gamma radiation spectrometer. However, its performance is adversely affected by point defects, structural and compositional heterogeneities within the crystals, such as twinning, pipes, grain boundaries (polycrystallinity), secondary phases and in some cases, damage caused by external forces. One example is damage that occurs during characterization of the surface by a laser during Raman spectroscopy. Even minimal laser power can cause Te enriched areas on the surface to appear. The Raman spectra resulting from measurements at moderate intensity laser power show large increases in peak intensity that is attributed to Te. Atomic Force Microscopy (AFM) was used to characterize the extent of damage to the CZT crystal surface following exposure to the Raman laser. AFM data reveal localized surface damage in the areas exposed to the Raman laser beam. The degree of surface damage to the crystal is dependent on the laser power, with the most observable damage occurring at high laser power. Moreover, intensity increases in the Te peaks of the Raman spectra are observed even at low laser power with little to no visible damage observed by AFM. AFM results also suggest that exposure to the same amount of laser power yields different amounts of surface damage depending on whether the exposed surface is the Te terminating face or the Cd terminating face of CZT.

Hawkins, S; Lucile Teague, L; Martine Duff, M; Eliel Villa-Aleman, E

2008-06-10T23:59:59.000Z

293

Control of Damage to Museum Objects by Optical Radiation  

NLE Websites -- All DOE Office Websites (Extended Search)

Control of Damage to Museum Objects by Optical Radiation Control of Damage to Museum Objects by Optical Radiation Speaker(s): Eliyahu Ne'eman Date: June 7, 2004 - 12:00pm Location: Bldg. 90 This Presentation is based on CIE Publication 157:2004 which has been recently published. It is the report of CIE Technical Committee 3-22 with the same title. Leading experts on Museum lighting from Australia, Canada, Finland, France, Japan, Germany, Great Britain, New Zealand and the USA, took part in writing this document. The two processes by which exposure to light may cause damage are photochemical action and radiant heating effect. These processes are examined and the characteristics of damage caused to museum objects are described. Recent research, which has aimed to relate the extent of exposure of materials to measures of damage

294

DNA Sequencing Using capillary Electrophoresis  

Science Conference Proceedings (OSTI)

The overall goal of this program was to develop capillary electrophoresis as the tool to be used to sequence for the first time the Human Genome. Our program was part of the Human Genome Project. In this work, we were highly successful and the replaceable polymer we developed, linear polyacrylamide, was used by the DOE sequencing lab in California to sequence a significant portion of the human genome using the MegaBase multiple capillary array electrophoresis instrument. In this final report, we summarize our efforts and success. We began our work by separating by capillary electrophoresis double strand oligonucleotides using cross-linked polyacrylamide gels in fused silica capillaries. This work showed the potential of the methodology. However, preparation of such cross-linked gel capillaries was difficult with poor reproducibility, and even more important, the columns were not very stable. We improved stability by using non-cross linked linear polyacrylamide. Here, the entangled linear chains could move when osmotic pressure (e.g. sample injection) was imposed on the polymer matrix. This relaxation of the polymer dissipated the stress in the column. Our next advance was to use significantly lower concentrations of the linear polyacrylamide that the polymer could be automatically blown out after each run and replaced with fresh linear polymer solution. In this way, a new column was available for each analytical run. Finally, while testing many linear polymers, we selected linear polyacrylamide as the best matrix as it was the most hydrophilic polymer available. Under our DOE program, we demonstrated initially the success of the linear polyacrylamide to separate double strand DNA. We note that the method is used even today to assay purity of double stranded DNA fragments. Our focus, of course, was on the separation of single stranded DNA for sequencing purposes. In one paper, we demonstrated the success of our approach in sequencing up to 500 bases. Other application papers of sequencing up to this level were also published in the mid 1990's. A major interest of the sequencing community has always been read length. The longer the sequence read per run the more efficient the process as well as the ability to read repeat sequences. We therefore devoted a great deal of time to studying the factors influencing read length in capillary electrophoresis, including polymer type and molecule weight, capillary column temperature, applied electric field, etc. In our initial optimization, we were able to demonstrate, for the first time, the sequencing of over 1000 bases with 90% accuracy. The run required 80 minutes for separation. Sequencing of 1000 bases per column was next demonstrated on a multiple capillary instrument. Our studies revealed that linear polyacrylamide produced the longest read lengths because the hydrophilic single strand DNA had minimal interaction with the very hydrophilic linear polyacrylamide. Any interaction of the DNA with the polymer would lead to broader peaks and lower read length. Another important parameter was the molecular weight of the linear chains. High molecular weight (> 1 MDA) was important to allow the long single strand DNA to reptate through the entangled polymer matrix. In an important paper, we showed an inverse emulsion method to prepare reproducibility linear polyacrylamide polymer with an average MWT of 9MDa. This approach was used in the polymer for sequencing the human genome. Another critical factor in the successful use of capillary electrophoresis for sequencing was the sample preparation method. In the Sanger sequencing reaction, high concentration of salts and dideoxynucleotide remained. Since the sample was introduced to the capillary column by electrokinetic injection, these salt ions would be favorably injected into the column over the sequencing fragments, thus reducing the signal for longer fragments and hence reading read length. In two papers, we examined the role of individual components from the sequencing reaction and then developed a protocol to reduce the deleterio

Dr. Barry Karger

2011-05-09T23:59:59.000Z

295

Bayesian models for DNA microarray data analysis  

E-Print Network (OSTI)

Selection of signi?cant genes via expression patterns is important in a microarray problem. Owing to small sample size and large number of variables (genes), the selection process can be unstable. This research proposes a hierarchical Bayesian model for gene (variable) selection. We employ latent variables in a regression setting and use a Bayesian mixture prior to perform the variable selection. Due to the binary nature of the data, the posterior distributions of the parameters are not in explicit form, and we need to use a combination of truncated sampling and Markov Chain Monte Carlo (MCMC) based computation techniques to simulate the posterior distributions. The Bayesian model is ?exible enough to identify the signi?cant genes as well as to perform future predictions. The method is applied to cancer classi?cation via cDNA microarrays. In particular, the genes BRCA1 and BRCA2 are associated with a hereditary disposition to breast cancer, and the method is used to identify the set of signi?cant genes to classify BRCA1 and others. Microarray data can also be applied to survival models. We address the issue of how to reduce the dimension in building model by selecting signi?cant genes as well as assessing the estimated survival curves. Additionally, we consider the wellknown Weibull regression and semiparametric proportional hazards (PH) models for survival analysis. With microarray data, we need to consider the case where the number of covariates p exceeds the number of samples n. Speci?cally, for a given vector of response values, which are times to event (death or censored times) and p gene expressions (covariates), we address the issue of how to reduce the dimension by selecting the responsible genes, which are controlling the survival time. This approach enables us to estimate the survival curve when n << p. In our approach, rather than ?xing the number of selected genes, we will assign a prior distribution to this number. The approach creates additional ?exibility by allowing the imposition of constraints, such as bounding the dimension via a prior, which in e?ect works as a penalty. To implement our methodology, we use a Markov Chain Monte Carlo (MCMC) method. We demonstrate the use of the methodology with (a) di?use large B??cell lymphoma (DLBCL) complementary DNA (cDNA) data and (b) Breast Carcinoma data. Lastly, we propose a mixture of Dirichlet process models using discrete wavelet transform for a curve clustering. In order to characterize these time??course gene expresssions, we consider them as trajectory functions of time and gene??speci?c parameters and obtain their wavelet coe?cients by a discrete wavelet transform. We then build cluster curves using a mixture of Dirichlet process priors.

Lee, Kyeong Eun

2006-05-01T23:59:59.000Z

296

Enhancing the DNA Patent Database  

Science Conference Proceedings (OSTI)

Final Report on Award No. DE-FG0201ER63171 Principal Investigator: LeRoy B. Walters February 18, 2008 This project successfully completed its goal of surveying and reporting on the DNA patenting and licensing policies at 30 major U.S. academic institutions. The report of survey results was published in the January 2006 issue of Nature Biotechnology under the title The Licensing of DNA Patents by US Academic Institutions: An Empirical Survey. Lori Pressman was the lead author on this feature article. A PDF reprint of the article will be submitted to our Program Officer under separate cover. The project team has continued to update the DNA Patent Database on a weekly basis since the conclusion of the project. The database can be accessed at dnapatents.georgetown.edu. This database provides a valuable research tool for academic researchers, policymakers, and citizens. A report entitled Reaping the Benefits of Genomic and Proteomic Research: Intellectual Property Rights, Innovation, and Public Health was published in 2006 by the Committee on Intellectual Property Rights in Genomic and Protein Research and Innovation, Board on Science, Technology, and Economic Policy at the National Academies. The report was edited by Stephen A. Merrill and Anne-Marie Mazza. This report employed and then adapted the methodology developed by our research project and quoted our findings at several points. (The full report can be viewed online at the following URL: http://www.nap.edu/openbook.php?record_id=11487&page=R1). My colleagues and I are grateful for the research support of the ELSI program at the U.S. Department of Energy.

Walters, LeRoy B.

2008-02-18T23:59:59.000Z

297

Cytotoxicological Response to Engineered Nanomaterials: A Pathway-Driven Process  

E-Print Network (OSTI)

Nanoparticles, while included in a growing number of consumer products, may pose risks to human health due to heavy metal leaching and/or the production of reactive oxygen species following exposures. Subcellular mechanisms of action triggered as a result of exposure to various nanoparticles are still largely unexplored. In this work, an effort to elucidate such toxicological parameters was accomplished by evaluating oxidative stress generation, changes in gene and protein expression, and cell cycle status after low-dose exposures to a variety of metal and carbon-based nanomaterials in primary human dermal cells. Additionally, mitigation of nanoparticle toxicity via microencapsulation was investigated to assess the feasibility of utilizing nanomaterials in dermally implantable biosensor applications. Cellular immune and inflammatory processes were measured via qPCR and immunoblotting, which revealed gene and protein expression modulation along the NF-kappaB pathway after a variety of nanoparticle exposures. The role of immunoregulatory transcription factor NF-kappaB was examined in an oxidative stress context in cells exposed to a panel of nanoparticles, whereby glutathione conversion and modulation of oxidative stress proteins in normal and NF-kappaB knockdown human dermal fibroblasts were monitored. Results revealed decreased antioxidant response and corresponding increased levels of oxidative stress and cell death in exposed normal cells, compared to NF-kappaB incompetent cells. However, reactive oxygen species production was not an absolute precursor to DNA damage, which was measured by the comet assay, gamma-H2AX expression, and flow cytometry. Protein analysis revealed that map kinase p38, rather than p53, was involved in the halting of the cell cycle in S-phase after ZnO exposures, which caused DNA double strand breaks. Microencapsulation of fluorescent quantum dot nanoparticles, specifically, was utilized as a method to improve system functionality and surrounding cellular viability for the purpose of a dermal analyte detection assay. In vitro results indicated a functional localization of nanoparticles, as well as cessation of cellular uptake. Subsequently, cellular metabolism was unaffected over the range of time and concentrations tested in comparison to unencapsulated quantum dot treatments, indicating the usefulness of this technique in developing nanoparticle-driven biomedical applications.

Romoser, Amelia Antonia

2012-05-01T23:59:59.000Z

298

DNA-guided nanoparticle assemblies  

DOE Patents (OSTI)

In some embodiments, DNA-capped nanoparticles are used to define a degree of crystalline order in assemblies thereof. In some embodiments, thermodynamically reversible and stable body-centered cubic (bcc) structures, with particles occupying <.about.10% of the unit cell, are formed. Designs and pathways amenable to the crystallization of particle assemblies are identified. In some embodiments, a plasmonic crystal is provided. In some aspects, a method for controlling the properties of particle assemblages is provided. In some embodiments a catalyst is formed from nanoparticles linked by nucleic acid sequences and forming an open crystal structure with catalytically active agents attached to the crystal on its surface or in interstices.

Gang, Oleg; Nykypanchuk, Dmytro; Maye, Mathew; van der Lelie, Daniel

2013-07-16T23:59:59.000Z

299

Immunoglobulin motif DNA recognition and  

E-Print Network (OSTI)

binding domains of NF-kB, NFAT1, p53 and the STAT proteins. NMR spectroscopy of a 43.6 kD RD­b­DNA ternary for NF-kB3-4, the nuclear factor of acti- vated T-cells NFAT1 (refs 5,6), STAT1 (ref. 7) and STAT3b8 72 and Ser 73. In con- trast, the N-terminus of NF-kB3-4 and NFAT1 (refs 5, 6) loops around

Sali, Andrej

300

Turbine Steam Path Damage: Theory and Practice, Volume 2: Damage Mechanisms  

Science Conference Proceedings (OSTI)

Historically, most treatises about steam turbines have concentrated on thermo-dynamics or design. In contrast, the primary focus of this book is on the problems that occur in the turbine steam path. Some of these problems have been long known to the industry, starting as early as A. Stodola's work at the turn of the century in which mechanisms such as solid particle erosion, corrosion and liquid droplet damage were recognized. What we have tried to do here is to provide, in a single, comprehensive refere...

1999-08-20T23:59:59.000Z

Note: This page contains sample records for the topic "dna damage response" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Characterisation of radiation damage in silicon photomultipliers with a Monte Carlo model  

E-Print Network (OSTI)

Measured response functions and low photon yield spectra of silicon photomultipliers (SiPM) were compared to multi-photoelectron pulse-height distributions generated by a Monte Carlo model. Characteristic parameters for SiPM were derived. The devices were irradiated with 14 MeV electrons at the Mainz microtron MAMI. It is shown that the first noticeable damage consists of an increase in the rate of dark pulses and the loss of uniformity in the pixel gains. Higher radiation doses reduced also the photon detection efficiency. The results are especially relevant for applications of SiPM in fibre detectors at high luminosity experiments.

S. Sanchez Majos; P. Achenbach; J. Pochodzalla

2008-05-27T23:59:59.000Z

302

Damage identification and health monitoring of structural and mechanical systems from changes in their vibration characteristics: A literature review  

SciTech Connect

This report contains a review of the technical literature concerning the detection, location, and characterization of structural damage via techniques that examine changes in measured structural vibration response. The report first categorizes the methods according to required measured data and analysis technique. The analysis categories include changes in modal frequencies, changes in measured mode shapes (and their derivatives), and changes in measured flexibility coefficients. Methods that use property (stiffness, mass, damping) matrix updating, detection of nonlinear response, and damage detection via neural networks are also summarized. The applications of the various methods to different types of engineering problems are categorized by type of structure and are summarized. The types of structures include beams, trusses, plates, shells, bridges, offshore platforms, other large civil structures, aerospace structures, and composite structures. The report describes the development of the damage-identification methods and applications and summarizes the current state-of-the-art of the technology. The critical issues for future research in the area of damage identification are also discussed.

Doebling, S.W.; Farrar, C.R.; Prime, M.B.; Shevitz, D.W.

1996-05-01T23:59:59.000Z

303

DNA sequencing using fluorescence background electroblotting membrane  

DOE Patents (OSTI)

A method for the multiplex sequencing on DNA is disclosed which comprises the electroblotting or specific base terminated DNA fragments, which have been resolved by gel electrophoresis, onto the surface of a neutral non-aromatic polymeric microporous membrane exhibiting low background fluorescence which has been surface modified to contain amino groups. Polypropylene membranes are preferably and the introduction of amino groups is accomplished by subjecting the membrane to radio or microwave frequency plasma discharge in the presence of an aminating agent, preferably ammonia. The membrane, containing physically adsorbed DNA fragments on its surface after the electroblotting, is then treated with crosslinking means such as UV radiation or a glutaraldehyde spray to chemically bind the DNA fragments to the membrane through said smino groups contained on the surface thereof. The DNA fragments chemically bound to the membrane are subjected to hybridization probing with a tagged probe specific to the sequence of the DNA fragments. The tagging may be by either fluorophores or radioisotopes. The tagged probes hybridized to said target DNA fragments are detected and read by laser induced fluorescence detection or autoradiograms. The use of aminated low fluorescent background membranes allows the use of fluorescent detection and reading even when the available amount of DNA to be sequenced is small. The DNA bound to the membrances may be reprobed numerous times.

Caldwell, Karin D. (Salt Lake City, UT); Chu, Tun-Jen (Salt Lake City, UT); Pitt, William G. (Orem, UT)

1992-01-01T23:59:59.000Z

304

DNA sequencing using fluorescence background electroblotting membrane  

DOE Patents (OSTI)

A method for the multiplex sequencing on DNA is disclosed which comprises the electroblotting or specific base terminated DNA fragments, which have been resolved by gel electrophoresis, onto the surface of a neutral non-aromatic polymeric microporous membrane exhibiting low background fluorescence which has been surface modified to contain amino groups. Polypropylene membranes are preferably and the introduction of amino groups is accomplished by subjecting the membrane to radio or microwave frequency plasma discharge in the presence of an aminating agent, preferably ammonia. The membrane, containing physically adsorbed DNA fragments on its surface after the electroblotting, is then treated with crosslinking means such as UV radiation or a glutaraldehyde spray to chemically bind the DNA fragments to the membrane through amino groups contained on the surface. The DNA fragments chemically bound to the membrane are subjected to hybridization probing with a tagged probe specific to the sequence of the DNA fragments. The tagging may be by either fluorophores or radioisotopes. The tagged probes hybridized to the target DNA fragments are detected and read by laser induced fluorescence detection or autoradiograms. The use of aminated low fluorescent background membranes allows the use of fluorescent detection and reading even when the available amount of DNA to be sequenced is small. The DNA bound to the membranes may be reprobed numerous times. No Drawings

Caldwell, K.D.; Chu, T.J.; Pitt, W.G.

1992-05-12T23:59:59.000Z

305

Topics in Forensic DNA Analysis & Interpretation  

Science Conference Proceedings (OSTI)

... Experience University of Virginia/FBI Laboratory (1992-1995) Work ... Most forensic DNA laboratories follow PCR ... for the polymer) If a lab is not ...

2011-03-24T23:59:59.000Z

306

Available Technologies: Highly Selective, Highly Efficient DNA ...  

... applications where extraction of minute amounts of DNA plays a critical role, such as in basic and applied molecular biology research, bioforensics, ...

307

Overview of DNA Programs at NIST  

Science Conference Proceedings (OSTI)

... during the PCR amplification process This is highly affected by DNA quantity and quality ... PCR inhibitors present in the sample may reduce PCR ...

2013-04-10T23:59:59.000Z

308

DNA Directed Assembly Probe for Detecting DNA-Protein Interaction in Microarray Format  

E-Print Network (OSTI)

Quantifying DNA-protein interaction using DNA microarrays are gaining increasing attention due to their ability to profile specificity of interactions in a high-throughput manner. This paper describes a new approach that ...

Ng, Jin Kiat

309

Damage Development on Stone Armored Breakwaters and Revetments  

E-Print Network (OSTI)

method to calculate damage progression on a rubble-mound breakwater, revetment, or jetty trunk armor layer. The methods apply to uniform-sized armor stone (0.75W50 ? W50 ? 1.25W50, W50 = median weight of armor stone) as well as riprap (0.125W50 ? W50 ? 4W50) exposed to depthlimited wave conditions. The equations discussed herein are primarily intended to be used as part of a life-cycle analysis, to predict the damage for a series of storms throughout the lifetime of the structure. This lifecycle analysis including damage prediction allows engineers to balance initial cost with expected maintenance costs in order to reduce the overall cost of the structure. The equations are intended to provide a tool for accurate damage estimates in order to reduce the possibility of unexpected maintenance costs. INTRODUCTION: Rubble-mound breakwater, revetment, and jetty projects require accurate damage prediction as part of life-cycle analyses. But few studies have been conducted to determine damage progression on stone armor layers for variable wave conditions over the life of a structure. Previous armor stability lab studies were intended to determine damage for the peak of a design storm. As such, most previous laboratory studies were begun with an undamaged

Jeffery A. Melby

2002-01-01T23:59:59.000Z

310

Precursors to potential severe core damage accidents: 1994, a status report. Volume 22: Appendix I  

Science Conference Proceedings (OSTI)

Nine operational events that affected eleven commercial light-water reactors (LWRs) during 1994 and that are considered to be precursors to potential severe core damage are described. All these events had conditional probabilities of subsequent severe core damage greater than or equal to 1.0 {times} 10{sup {minus}6}. These events were identified by computer-screening the 1994 licensee event reports from commercial LWRs to identify those that could be potential precursors. Candidate precursors were then selected and evaluated in a process similar to that used in previous assessments. Selected events underwent engineering evaluation that identified, analyzed, and documented the precursors. Other events designated by the Nuclear Regulatory Commission (NRC) also underwent a similar evaluation. Finally, documented precursors were submitted for review by licensees and NRC headquarters and regional offices to ensure that the plant design and its response to the precursor were correctly characterized. This study is a continuation of earlier work, which evaluated 1969--1981 and 1984--1993 events. The report discusses the general rationale for this study, the selection and documentation of events as precursors, and the estimation of conditional probabilities of subsequent severe core damage for events. This document is bound in two volumes: Vol. 21 contains the main report and Appendices A--H; Vol. 22 contains Appendix 1.

Belles, R.J.; Cletcher, J.W.; Copinger, D.A.; Vanden Heuvel, L.N. [Oak Ridge National Lab., TN (United States)] [Oak Ridge National Lab., TN (United States); Dolan, B.W.; Minarick, J.W. [Oak Ridge National Lab., TN (United States)] [Oak Ridge National Lab., TN (United States); [Science Applications International Corp., Oak Ridge, TN (United States)

1995-12-01T23:59:59.000Z

311

A study of radiation damage effects on the magnetic structure of bulk Iron  

SciTech Connect

Defects, defect interactions, and defect dynamics in solids created by fast neutrons are known to have significant impact on the performance and lifetime of structural materials. A fundamental understanding of the radiation damage effects in solids is therefore of great importance in assisting the development of improved materials - materials with ultrahigh strength, toughness, and radiation resistance. In this presentation, we show our recent theoretical investigation on the magnetic structure evolution of bulk iron in the region of the radiation defects. We applied a linear scaling ab-initio method based on density functional theory with local spin density approximation, namely the locally self-consistent multiple scattering method (LSMS), to the study of magnetic moment distributions in a cascade at the damage peak and for a series of time steps as the interstitials and vacancies recombined. Atomic positions correspond to those in a low energy cascade in a 10|000 atom sample, in which the primary damage state and the evolution of all defects produced were simulated using molecular dynamics with empirical, embedded-atom inter-atomic potentials. We will discuss how a region of affected moments expands and then recedes in response to a cascade evolution.

Wang Yang [Pittsburgh Supercomputing Center, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Nicholson, D. M. C.; Stocks, G. M.; Rusanu, Aurelian; Eisenbach, Markus; Stoller, R. E. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2011-04-01T23:59:59.000Z

312

A study of radiation damage effects on the magnetic structure of bulk Iron  

Science Conference Proceedings (OSTI)

Defects, defect interactions, and defect dynamics in solids created by fast neutrons are known to have significant impact on the performance and lifetime of structural materials. A fundamental understanding of the radiation damage effects in solids is therefore of great importance in assisting the development of improved materials - materials with ultrahigh strength, toughness, and radiation resistance. In this presentation, we show our recent theoretical investigation on the magnetic structure evolution of bulk iron in the region of the radiation defects. We applied a linear scaling ab-initio method based on density functional theory with local spin density approximation, namely the locally self-consistent multiple scattering method (LSMS), to the study of magnetic moment distributions in a cascade at the damage peak and for a series of time steps as the interstitials and vacancies recombined. Atomic positions correspond to those in a low energy cascade in a 10|000 atom sample, in which the primary damage state and the evolution of all defects produced were simulated using molecular dynamics with empirical, embedded-atom inter-atomic potentials. We will discuss how a region of affected moments expands and then recedes in response to a cascade evolution. VC 2011 American Institute of Physics. [doi:10.1063/1.3553937

Wang, Yang Nmn [ORNL; Nicholson, Don M [ORNL; Stocks, George Malcolm [ORNL; Rusanu, Aurelian [ORNL; Eisenbach, Markus [ORNL; Stoller, Roger E [ORNL

2011-01-01T23:59:59.000Z

313

A study of radiation damage effects on the magnetic structure of bulk Iron  

Science Conference Proceedings (OSTI)

Defects, defect interactions, and defect dynamics in solids created by fast neutrons are known to have significant impact on the performance and lifetime of structural materials. A fundamental understanding of the radiation damage effects in solids is therefore of great importance in assisting the development of improved materials - materials with ultrahigh strength, toughness, and radiation resistance. In this presentation, we show our recent theoretical investigation on the magnetic structure evolution of bulk iron in the region of the radiation defects. We applied a linear scaling ab-initio method based on density functional theory with local spin density approximation, namely the locally self-consistent multiple scattering method (LSMS), to the study of magnetic moment distributions in a cascade at the damage peak and for a series of time steps as the interstitials and vacancies recombined. Atomic positions correspond to those in a low energy cascade in a 10|000 atom sample, in which the primary damage state and the evolution of all defects produced were simulated using molecular dynamics with empirical, embedded-atom inter-atomic potentials. We will discuss how a region of affected moments expands and then recedes in response to a cascade evolution.

Wang, Yang [Pittsburgh Supercomputing Center; Stocks, George Malcolm [ORNL; Stoller, Roger E [ORNL; Nicholson, Don M [ORNL; Rusanu, Aurelian [ORNL; Eisenbach, Markus [ORNL

2011-01-01T23:59:59.000Z

314

Feasibility of impact-acoustic emissions for detection of damaged wheat kernels  

Science Conference Proceedings (OSTI)

A non-destructive, real time device was developed to detect insect damage, sprout damage, and scab damage in kernels of wheat. Kernels are impacted onto a steel plate and the resulting acoustic signal analyzed to detect damage. The acoustic signal was ... Keywords: Acoustic emissions, Insect damage kernels, Neural network, Sorting, Spectral analysis

Tom C. Pearson; A. Enis Cetin; Ahmed H. Tewfik; Ron P. Haff

2007-05-01T23:59:59.000Z

315

JOURNAL OF STRUCTURAL ENGINEERING / JANUARY 1999 / 89 REDUCTION OF STRUCTURAL DAMAGE BY NONLINEAR SOIL RESPONSE  

E-Print Network (OSTI)

the other average values of N¯ for n = 0 (in the first row of Table 1) would result in the linear trend ¯log

Southern California, University of

316

MODELING OF THE ELECTRO-MECHANICAL (E/M) IMPEDANCE RESPONSE OF A DAMAGED COMPOSITE BEAM  

E-Print Network (OSTI)

with far reaching implications in the management and preservation of nations aging infrastructure. Among and the applied force are utilized to deduce general expressions for pointwise dynamic stiffness and pointwise

Giurgiutiu, Victor

317

Metabolomic Response of Human Skin Tissue to Low Dose Ionizing Radiation  

Science Conference Proceedings (OSTI)

Understanding how human organs respond to ionizing radiation (IR) at a systems biology level and identifying biomarkers for IR exposure at low doses can help provide a scientific basis for establishing radiation protection standards. Little is known regarding the physiological responses to low dose IR at the metabolite level, which represents the end-point of biochemical processes inside cells. Using a full thickness human skin tissue model and GC-MS-based metabolomics analysis, we examined the metabolic perturbations at three time points (3, 24 and 48 hr) after exposure to 3, 10 and 200 cGy of X-rays. PLS-DA score plots revealed dose- and time-dependent clustering between sham and irradiated groups. Importantly, a comparable number of metabolites were detected to have significant change 48 hr after exposure to 3 and 10 cGy of irradiation, when compared with the high dose of 200 cGy. Biochemical pathway analysis showed perturbations to DNA/RNA damage and repair, lipid and energy metabolisms, even at low doses of IR.

Hu, Zeping; Kim, Young-Mo; Sowa, Marianne B.; Robinson, Robert J.; Gao, Xiaoli; Metz, Thomas O.; Morgan, William F.; Zhang, Qibin

2012-05-18T23:59:59.000Z

318

Characterizing wind turbine system response to lightning activity  

DOE Green Energy (OSTI)

A lightning protection research program was instituted by National Renewable Energy Laboratory to minimize lightning damage to wind turbines and to further the understanding of effective damage mitigation techniques. To that end, a test program is under way to observe lightning activity, protection system response, and damage at a wind power plant in the Department of Energy (DOE) and Electric Power Research Institute (EPRI) Turbine Verification Program. The authors installed Lightning activated surveillance cameras along with a special storm tracking device to observe the activity in the wind plant area. They instrumented the turbines with lightning and ground current detection devices to log direct and indirect strike activity at each unit. They installed a surge monitor on the utility interface to track incoming activity from the transmission lines. Maintenance logs are used to verify damage and determine downtime and repair costs. Actual strikes to turbines were recorded on video and ancillary devices. The test setup and some results are discussed in this paper.

McNiff, B.; LaWhite, N. [McNiff Light Industry, Harborside, ME (United States); Muljadi, E. [National Renewable Energy Lab., Golden, CO (United States)

1998-07-01T23:59:59.000Z

319

DNA repair efficiency in germ cells and early mouse embryos and consequences for radiation-induced transgenerational genomic damage  

E-Print Network (OSTI)

mutation rate in the post-chernobyl families from ukraine.mutation rate after the Chernobyl accident. Nature 380, 683-fallout following the Chernobyl accident (Dubrova et al. ,

Marchetti, Francesco

2009-01-01T23:59:59.000Z

320

Integrated Molecular Analysis Indicates Undetectable Change in DNA Damage in Mice after Continuous Irradiation at ~ 400-fold Natural Background Radiation  

E-Print Network (OSTI)

Background: In the event of a nuclear accident, people are exposed to elevated levels of continuous low dose-rate radiation. Nevertheless, most of the literature describes the biological effects of acute radiation.

Olipitz, Werner

Note: This page contains sample records for the topic "dna damage response" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Sources of Data on Freezing Rain and Resulting Damages  

Science Conference Proceedings (OSTI)

Freezing rain produces major damages each year in the United States, and various affected groups continue to seek data on the incidence and losses produced by freezing rain. The various kinds of data available about freezing rain and related ...

Stanley A. Changnon; Tamara G. Creech

2003-10-01T23:59:59.000Z

322

Damage to residential structures from surface mine blasting  

SciTech Connect

The Bureau of Mines has studied the problem of cracking in residential structure walls from vibrations produced by blasting in surface mines. Direct observations were made of blasting damage consisting primarily of cosmetic cracking.

Siskind, D.E.

1980-01-01T23:59:59.000Z

323

Development of Damage Tolerant Inco 718 for High Temperature ...  

Science Conference Proceedings (OSTI)

697-712. 7. M. Chang et al, Damage tolerance of alloy 718 turbine disc material,. Superalloys. 92, ed. S. Antolovitch et al. (Warrendale,. PA : TMS 1992) 446-456.

324

Spectral identification of ozone-damaged pine needles  

Science Conference Proceedings (OSTI)

Needles were collected from ponderosa and Jeffrey pine trees at three sites in the Sierra Nevada, and were assembled into 504 samples and grouped according to five dominant live needle conditions-green, winter fleck, sucking insect damage, scale insect ...

A. V. Di Vittorio; G. S. Biging

2009-01-01T23:59:59.000Z

325

Insured Lightning-Caused Property Damage in Three Western States  

Science Conference Proceedings (OSTI)

Insurance claims resulting from lightning damage in Colorado, Utah, and Wyoming were analyzed during the period from 1987 to 1993. Most claims were from personal accounts, while some were commercial.

Ronald L. Holle; Ral E. Lpez; Lowell J. Arnold; John Endres

1996-08-01T23:59:59.000Z

326

Fast neutron Damage Studies on NdFeB Materials  

E-Print Network (OSTI)

J. Spencer, Z. Wolf and J. Volk, Radiation Damage StudiesMcClellan, CA 95652 and J. Volk, FNAL, Batavia, Il 60510,PI), James E. Spencer, James T. Volk and Zachary R. Wolf,

2005-01-01T23:59:59.000Z

327

Neutron and gamma irradiation damage to organic materials.  

SciTech Connect

This document discusses open literature reports which investigate the damage effects of neutron and gamma irradiation on polymers and/or epoxies - damage refers to reduced physical chemical, and electrical properties. Based on the literature, correlations are made for an SNL developed epoxy (Epon 828-1031/DDS) with an expected total fast-neutron fluence of {approx}10{sup 12} n/cm{sup 2} and a {gamma} dosage of {approx}500 Gy received over {approx}30 years at < 200 C. In short, there are no gamma and neutron irradiation concerns for Epon 828-1031/DDS. To enhance the fidelity of our hypotheses, in regards to radiation damage, we propose future work consisting of simultaneous thermal/irradiation (neutron and gamma) experiments that will help elucidate any damage concerns at these specified environmental conditions.

White, Gregory Von, II; Bernstein, Robert

2012-04-01T23:59:59.000Z

328

Neutron and gamma irradiation damage to organic materials.  

Science Conference Proceedings (OSTI)

This document discusses open literature reports which investigate the damage effects of neutron and gamma irradiation on polymers and/or epoxies - damage refers to reduced physical chemical, and electrical properties. Based on the literature, correlations are made for an SNL developed epoxy (Epon 828-1031/DDS) with an expected total fast-neutron fluence of {approx}10{sup 12} n/cm{sup 2} and a {gamma} dosage of {approx}500 Gy received over {approx}30 years at irradiation concerns for Epon 828-1031/DDS. To enhance the fidelity of our hypotheses, in regards to radiation damage, we propose future work consisting of simultaneous thermal/irradiation (neutron and gamma) experiments that will help elucidate any damage concerns at these specified environmental conditions.

White, Gregory Von, II; Bernstein, Robert

2012-04-01T23:59:59.000Z

329

Windspeed Analyses of Tornadoes Based on Structural Damage  

Science Conference Proceedings (OSTI)

Documentation is presented for the tornadoes of 28 June 1979 in the Iowa towns of Manson and Algona. Analyses of failed engineered and nonengineered structures are presented with an emphasis on those studies of observed damage that can form the ...

Amde M. Wolde-Tinsae; Max L. Porter; Donald I. McKeown

1985-07-01T23:59:59.000Z

330

Conservation of Severely Damaged Paper Using Passivation Polymers  

E-Print Network (OSTI)

This work examined the use of passivation polymers in the conservation of severely damaged paper. It specifically investigated the use of this functional polymer treatment to address the issues of damage to paper caused by waterlogging, mold, and internal acidity. Several experiments were designed and conducted to examine the effects of the polymers in the conservation of papers compromised by these conditions. Paper artifacts from the Bonfire Memorabilia Collection were selected and conserved using treatment protocols that included the use of the passivation polymers. The conservation of some of the damaged papers from this culturally important site demonstrated the effectiveness of the polymer treatment in real-world conservation situations. This dissertation established that the use of passivation polymers adds strength and stability to severely damaged paper.

Eilert, Eloise

2011-08-01T23:59:59.000Z

331

Normalized Hurricane Damages in the United States: 192595  

Science Conference Proceedings (OSTI)

Hurricanes are the costliest natural disasters in the United States. Understanding how both hurricane frequencies and intensities vary from year to year as well as how this is manifested in changes in damages that occur is a topic of great ...

Roger A. Pielke Jr.; Christopher W. Landsea

1998-09-01T23:59:59.000Z

332

Jet Engine Coatings Resist Volcanic Ash Damage - Materials ...  

Science Conference Proceedings (OSTI)

Posted on: 4/27/2011 12:00:00 AM... Concerns about the damage that volcanic ash clouds can inflict on aircraft engines resulted in last year's $2 billion...

333

Radiation Damage Studies with Hadrons on Materials and Electronics  

E-Print Network (OSTI)

SLAC-PUB-10534 July 2004 Radiation Damage Studies withJ. Spencer. , Z. Wolf, SLAC, Menlo Park, CA 94025, USA M.J. Spencer ? Z. Wolf, SLAC, Menlo Park, CA 94025, USA M.

2004-01-01T23:59:59.000Z

334

Fast neutron Damage Studies on NdFeB Materials  

E-Print Network (OSTI)

High-Level Dosimeters used in the SLAC Photon andNeutron Fields, SLAC-PUB-8517, 2002. [7] G. Gross, J.SLAC-PUB-11219 May2005 Fast Neutron Damage Studies on NdFeB

2005-01-01T23:59:59.000Z

335

RADIATION DAMAGE TO BSCCO-2223 FROM 50 MEV PROTONS  

E-Print Network (OSTI)

B. and Gupta, R. , Radiation Resistant Magnets for the RIARADIATION DAMAGE TO BSCCO-2223 FROM 50 MEV PROTONS A. F.HTS materials in high radiation environments requires that

Zeller, A.F.; Ronningen, R.M.; Godeke, A.; Heilbronn, L.H.; McMahan-Norris, P.; Gupta, R.

2007-01-01T23:59:59.000Z

336

Tropical Cyclone Damages in China 19832006  

Science Conference Proceedings (OSTI)

Based on damage records released by the Department of Civil Affairs of China, direct economic losses and casualties associated with tropical cyclones that made landfall over China during 19832006 are examined. In an average year, landfalling ...

Qiang Zhang; Qiufeng Liu; Liguang Wu

2009-04-01T23:59:59.000Z

337

Activation and radiation damage in the environment of hadron accelerators  

E-Print Network (OSTI)

A component which suffers radiation damage usually also becomes radioactive, since the source of activation and radiation damage is the interaction of the material with particles from an accelerator or with reaction products. However, the underlying mechanisms of the two phenomena are different. These mechanisms are described here. Activation and radiation damage can have far-reaching consequences. Components such as targets, collimators, and beam dumps are the first candidates for failure as a result of radiation damage. This means that they have to be replaced or repaired. This takes time, during which personnel accumulate dose. If the dose to personnel at work would exceed permitted limits, remote handling becomes necessary. The remaining material has to be disposed of as radioactive waste, for which an elaborate procedure acceptable to the authorities is required. One of the requirements of the authorities is a complete nuclide inventory. The methods used for calculation of such inventories are presented,...

Kiselev, Daniela

2013-01-01T23:59:59.000Z

338

Microsoft Word - SWPAIceStormDamage_021009.doc  

NLE Websites -- All DOE Office Websites (Extended Search)

Department of Energy (DOE), continues to make steady progress in its efforts to restore transmission lines in Arkansas and Missouri damaged during an ice storm on January 26-27,...

339

Microsoft Word - SWPAIceStormDamage_020609.doc  

NLE Websites -- All DOE Office Websites (Extended Search)

Department of Energy (DOE), continues to make steady progress in its efforts to restore transmission lines in Arkansas and Missouri damaged during a January 27-28, 2009 ice...

340

Recombinant DNA encoding a desulfurization biocatalyst  

DOE Patents (OSTI)

This invention relates to a recombinant DNA molecule containing a gene or genes which encode a biocatalyst capable of desulfurizing a fossil fuel which contains organic sulfur molecules. For example, the present invention encompasses a recombinant DNA molecule containing a gene or genes of a strain of Rhodococcus rhodochrous.

Rambosek, John (Seattle, WA); Piddington, Chris S. (Seattle, WA); Kovacevich, Brian R. (Seattle, WA); Young, Kevin D. (Grand Forks, ND); Denome, Sylvia A. (Thompson, ND)

1994-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "dna damage response" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Recombinant DNA encoding a desulfurization biocatalyst  

DOE Patents (OSTI)

This invention relates to a recombinant DNA molecule containing a gene or genes which encode a biocatalyst capable of desulfurizing a fossil fuel which contains organic sulfur molecules. For example, the present invention encompasses a recombinant DNA molecule containing a gene or genes of a strain of Rhodococcus rhodochrous. 13 figs.

Rambosek, J.; Piddington, C.S.; Kovacevich, B.R.; Young, K.D.; Denome, S.A.

1994-10-18T23:59:59.000Z

342

The Initiation of Bacterial DNA Replication  

NLE Websites -- All DOE Office Websites (Extended Search)

The Initiation of Bacterial DNA The Initiation of Bacterial DNA Replication The Initiation of Bacterial DNA Replication Print Wednesday, 31 January 2007 00:00 For the first time, scientists have determined the structure of the initiator of bacterial DNA replication. It is already known that such replication is controlled by a protein known as DnaA, a member of the AAA+ superfamily of ATPases. What has now been discovered is that the core of the initiator is not the closed-ring structure expected for this system. Instead, DnaA forms an open right-handed helix. In addition, the architecture indicates that this AAA+ superhelix will wrap coils of the DNA around its exterior, causing the DNA double helix to deform as a first step in the separation and unwinding of its strands. Eukaryotic and archaeal initiators also have the structural elements that promote open-helix formation, indicating that a spiral, open-ring AAA+ assembly is a conserved element from a common evolutionary ancestor of Archaea, Bacteria, and Eukarya.

343

Evaluation of Explosive Cleaning Damage in Ferritic Boiler Tubes  

Science Conference Proceedings (OSTI)

Utilities have reported boiler tube damage after explosive cleaning to control or remove slag deposits. The damage typically consists of tube crushing, denting, microcracking, and inner diameter (ID) initiated cracking. Because the latter two might not propagate through tube wall thickness initially, these types of cracking are not commonly detected during the cleaning process. However, tube failures after the boiler resumed service have been attributed to these ID-related cracking. Many utilities have r...

2010-10-29T23:59:59.000Z

344

Allosteric Modulation of DNA by Small Molecules  

NLE Websites -- All DOE Office Websites (Extended Search)

Allosteric Modulation of DNA by Small Allosteric Modulation of DNA by Small Molecules Signals originating at the cell surface are conveyed by a complex system of interconnected signaling pathways to the nucleus. They converge at transcription factors, which in turn regulate the transcription of sets of genes that result in the gene expression. Many human diseases are caused by dysregulated gene expression and the oversupply of transcription factors may be required for the growth and metastatic behavior of human cancers. Cell permeable small molecules that can be programmed to disrupt transcription factor-DNA interfaces could silence aberrant gene expression pathways. Pyrrole-imidazole polyamides are DNA minor groove binding small molecules that are programmable for a large repertoire of DNA motifs.

345

Storing data encoded DNA in living organisms  

DOE Patents (OSTI)

Current technologies allow the generation of artificial DNA molecules and/or the ability to alter the DNA sequences of existing DNA molecules. With a careful coding scheme and arrangement, it is possible to encode important information as an artificial DNA strand and store it in a living host safely and permanently. This inventive technology can be used to identify origins and protect R&D investments. It can also be used in environmental research to track generations of organisms and observe the ecological impact of pollutants. Today, there are microorganisms that can survive under extreme conditions. As well, it is advantageous to consider multicellular organisms as hosts for stored information. These living organisms can provide as memory housing and protection for stored data or information. The present invention provides well for data storage in a living organism wherein at least one DNA sequence is encoded to represent data and incorporated into a living organism.

Wong; Pak C. (Richland, WA), Wong; Kwong K. (Sugar Land, TX), Foote; Harlan P. (Richland, WA)

2006-06-06T23:59:59.000Z

346

Method for sequencing DNA base pairs  

DOE Patents (OSTI)

The base pairs of a DNA structure are sequenced with the use of a scanning tunneling microscope (STM). The DNA structure is scanned by the STM probe tip, and, as it is being scanned, the DNA structure is separately subjected to a sequence of infrared radiation from four different sources, each source being selected to preferentially excite one of the four different bases in the DNA structure. Each particular base being scanned is subjected to such sequence of infrared radiation from the four different sources as that particular base is being scanned. The DNA structure as a whole is separately imaged for each subjection thereof to radiation from one only of each source. 6 figures.

Sessler, A.M.; Dawson, J.

1993-12-14T23:59:59.000Z

347

Improved method for sequencing DNA base pairs  

DOE Patents (OSTI)

The base pairs of a DNA structure are sequenced with the use of a scanning tunneling microscope (STM). The DNA structure is scanned by the STM probe tip, and, as it is being scanned, the DNA structure is separately subjected to a sequence of infrared radiation from four different sources, each source being selected to preferentially excite one of the four different bases in the DNA structure. Each particular base being scanned is subjected to such sequence of infrared radiation from the four different sources as that particular base is being scanned. The DNA structure as a whole is separately imaged for each subjection thereof to radiation from one only of each source. 1 ref.

Sessler, A.M.; Dawson, J.

1990-12-31T23:59:59.000Z

348

Improved method for sequencing DNA base pairs  

DOE Patents (OSTI)

The base pairs of a DNA structure are sequenced with the use of a scanning tunneling microscope (STM). The DNA structure is scanned by the STM probe tip, and, as it is being scanned, the DNA structure is separately subjected to a sequence of infrared radiation from four different sources, each source being selected to preferentially excite one of the four different bases in the DNA structure. Each particular base being scanned is subjected to such sequence of infrared radiation from the four different sources as that particular base is being scanned. The DNA structure as a whole is separately imaged for each subjection thereof to radiation from one only of each source. 1 ref.

Sessler, A.M.; Dawson, J.

1990-01-01T23:59:59.000Z

349

Flow cytometric detection method for DNA samples  

Science Conference Proceedings (OSTI)

Disclosed herein are two methods for rapid multiplex analysis to determine the presence and identity of target DNA sequences within a DNA sample. Both methods use reporting DNA sequences, e.g., modified conventional Taqman.RTM. probes, to combine multiplex PCR amplification with microsphere-based hybridization using flow cytometry means of detection. Real-time PCR detection can also be incorporated. The first method uses a cyanine dye, such as, Cy3.TM., as the reporter linked to the 5' end of a reporting DNA sequence. The second method positions a reporter dye, e.g., FAM.TM. on the 3' end of the reporting DNA sequence and a quencher dye, e.g., TAMRA.TM., on the 5' end.

Nasarabadi,Shanavaz (Livermore, CA); Langlois, Richard G. (Livermore, CA); Venkateswaran, Kodumudi S. (Round Rock, TX)

2011-07-05T23:59:59.000Z

350

Flow cytometric detection method for DNA samples  

DOE Patents (OSTI)

Disclosed herein are two methods for rapid multiplex analysis to determine the presence and identity of target DNA sequences within a DNA sample. Both methods use reporting DNA sequences, e.g., modified conventional Taqman.RTM. probes, to combine multiplex PCR amplification with microsphere-based hybridization using flow cytometry means of detection. Real-time PCR detection can also be incorporated. The first method uses a cyanine dye, such as, Cy3.TM., as the reporter linked to the 5' end of a reporting DNA sequence. The second method positions a reporter dye, e.g., FAM, on the 3' end of the reporting DNA sequence and a quencher dye, e.g., TAMRA, on the 5' end.

Nasarabadi, Shanavaz (Livermore, CA); Langlois, Richard G. (Livermore, CA); Venkateswaran, Kodumudi S. (Livermore, CA)

2006-08-01T23:59:59.000Z

351

Flow cytometric detection method for DNA samples  

DOE Patents (OSTI)

Disclosed herein are two methods for rapid multiplex analysis to determine the presence and identity of target DNA sequences within a DNA sample. Both methods use reporting DNA sequences, e.g., modified conventional Taqman.RTM. probes, to combine multiplex PCR amplification with microsphere-based hybridization using flow cytometry means of detection. Real-time PCR detection can also be incorporated. The first method uses a cyanine dye, such as, Cy3.TM., as the reporter linked to the 5' end of a reporting DNA sequence. The second method positions a reporter dye, e.g., FAM.TM. on the 3' end of the reporting DNA sequence and a quencher dye, e.g., TAMRA.TM., on the 5' end.

Nasarabadi,Shanavaz (Livermore, CA); Langlois, Richard G. (Livermore, CA); Venkateswaran, Kodumudi S. (Round Rock, TX)

2011-07-05T23:59:59.000Z

352

Property:NEPA DNA Worksheet | Open Energy Information  

Open Energy Info (EERE)

DNA Worksheet DNA Worksheet Jump to: navigation, search Property Name NEPA DNA Worksheet Property Type Page Description DNA Worksheet files for NEPA Docs. This is a property of type Page. It links to pages that use the form NEPA_Doc. Pages using the property "NEPA DNA Worksheet" Showing 19 pages using this property. D DOI-BLM-NV-C010-2011-0517-DNA + DOI-BLM-NV-C010-2011-0517-DNA.pdf + DOI-BLM-NV-C010-2012--044-DNA + DOI-BLM-NV-C010-2012-0044-DNA.pdf + DOI-BLM-NV-C010-2012-0005-DNA + DOI-BLM-NV-C010-2012-0005-DNA.pdf + DOI-BLM-NV-C010-2012-0016-DNA + DOI-BLM-NV-C010-2012-0016-DNA.pdf + DOI-BLM-NV-C010-2012-0019-DNA + DOI-BLM-NV-C010-2012-0019-DNA.pdf + DOI-BLM-NV-C010-2012-0020-DNA + DOI-BLM-NV-C010-2012-0020-DNA.pdf + DOI-BLM-NV-C010-2012-0028-DNA + DOI-BLM-NV-C010-2012-0028-DNA.pdf +

353

Probing Radiation Damage in Plutonium Alloys with Multiple Measurement Techniques  

SciTech Connect

A material subjected to radiation damage will usually experience changes in its physical properties. Measuring these changes in the physical properties provides a basis to study radiation damage in a material which is important for a variety of real world applications from reactor materials to semiconducting devices. When investigating radiation damage, the relative sensitivity of any given property can vary considerably based on the concentration and type of damage present as well as external parameters such as the temperature and starting material composition. By measuring multiple physical properties, these differing sensitivities can be leveraged to provide greater insight into the different aspects of radiation damage accumulation, thereby providing a broader understanding of the mechanisms involved. In this report, self-damage from {alpha}-particle decay in Pu is investigated by measuring two different properties: magnetic susceptibility and resistivity. The results suggest that while the first annealing stage obeys second order chemical kinetics, the primary mechanism is not the recombination of vacancy-interstitial close pairs.

McCall, S K; Fluss, M J; Chung, B W

2010-04-21T23:59:59.000Z

354

When DNA Needs to Stand Up and Be Counted  

NLE Websites -- All DOE Office Websites (Extended Search)

When DNA Needs to Stand Up and Be Counted When DNA Needs to Stand Up and Be Counted Print Wednesday, 31 May 2006 00:00 DNA microarrays are small metal, glass, or silicon chips...

355

Crystal Structure of the Chromodomain Helicase DNA-binding Protein 1 (Chd1) DNA-binding Domain in Complex with DNA  

Science Conference Proceedings (OSTI)

Chromatin remodelers are ATP-dependent machines that dynamically alter the chromatin packaging of eukaryotic genomes by assembling, sliding, and displacing nucleosomes. The Chd1 chromatin remodeler possesses a C-terminal DNA-binding domain that is required for efficient nucleosome sliding and believed to be essential for sensing the length of DNA flanking the nucleosome core. The structure of the Chd1 DNA-binding domain was recently shown to consist of a SANT and SLIDE domain, analogous to the DNA-binding domain of the ISWI family, yet the details of how Chd1 recognized DNA were not known. Here we present the crystal structure of the Saccharomyces cerevisiae Chd1 DNA-binding domain in complex with a DNA duplex. The bound DNA duplex is straight, consistent with the preference exhibited by the Chd1 DNA-binding domain for extranucleosomal DNA. Comparison of this structure with the recently solved ISW1a DNA-binding domain bound to DNA reveals that DNA lays across each protein at a distinct angle, yet contacts similar surfaces on the SANT and SLIDE domains. In contrast to the minor groove binding seen for Isw1 and predicted for Chd1, the SLIDE domain of the Chd1 DNA-binding domain contacts the DNA major groove. The majority of direct contacts with the phosphate backbone occur only on one DNA strand, suggesting that Chd1 may not strongly discriminate between major and minor grooves.

Sharma A.; Heroux A.; Jenkins K. R.; Bowman G. D.

2011-12-09T23:59:59.000Z

356

Investigation of Conditions for Moisture Damage in Asphalt Concrete and Appropriate Laboratory Test Methods  

E-Print Network (OSTI)

Study of Moisture Damage Test Methods for Evaluatingart and Critical Review of Test Methods. NCAT Report No.Pavement Moisture-Damage Test. Transportation Research

Lu, Qing

2005-01-01T23:59:59.000Z

357

Effects of garlic on cellular doubling time and DNA strand breaks caused by UV light and BPL, enhanced with catechol and TPA  

Science Conference Proceedings (OSTI)

3T3 cell cultures were exposed to UV light and Beta-Propiolactone. Neoplastic cell transformation (TF) was demonstrated after concurrent addition of catechol, or repeated addition of TPA. Addition of garlic to all fluences/concentrations of the carcinogen/cocarcinogen/promoter groups reduced the number of transformed foci/dish by at least 40%. Since the cell cycle is prolonged following exposure to carcinogens, it is likely the cell requires a longer time to repair this damage. The doubling time (DT) was extended from 12 to 36 hrs. when cells were exposed to BPL and from 12 o 28 hrs. when cells were exposed to 3.0J/M2/sec. If an anticarcinogenic compound is also added, it is reasonable to assume that the cell cycle may be further elongated. The cell cycle, denoted by DT was lengthened from 12 to 47 hrs and from 12 to 86 hrs for BPL and UVC, respectively. The extensions occurred in a dope dependent manner. The concentrations of the cocarcinogen and promoter remained constant throughout the experiment. When strand breaks were determined at the same dose sequences, by alkaline elution, more repair was seen with garlic where the lowest and middle doses of BPL were used and almost no decrease in % DNA eluted was seen with UVC exposed cells. With catechol, there was a two-fold decrease in % DNA eluted at the lowest and middle fluences. When TPA was added, all three fluences of UVC showed more than a threefold decrease in % DNA eluted. BPS with both TPA and catechol, again showed a reduction in strand breaks only low and middle doses. Both a direct-acting alkylating agent, BPL, and a physical carcinogen, UVC, were homogeneously affected, in terms of doubling time, but not when strand break repair was examined. A separate mechanism may be responsible for repair, and the mechanism associated with combinations of physical carcinogen enhancing agents combined with some non-carcinogens may be more profoundly affected by some natural products.

Baturay, N.Z.; Gayle, F.; Liu, S.; Kreidinger, C.

1995-11-01T23:59:59.000Z

358

Header and Drum Damage: Theory and Practice: Volume 1: Information Common to All Damage Types; Volume 2: Mechanisms  

Science Conference Proceedings (OSTI)

Headers and drums represent two of the largest and most expensive components in boilers. Particularly in the case of high-temperature headers, there are considerable safety concerns when operating aging plants, and some notable failures have occurred. For these reasons, understanding the types of damage that can accumulate and dealing with that damage are vital to the safe and economic operation of fossil power plants.

2003-12-31T23:59:59.000Z

359

The effects of shockwave profile shape and shock obliquity on spallation in Cu and Ta: kinetic and stress-state effects on damage evolution(u)  

SciTech Connect

Widespread research over the past five decades has provided a wealth of experimental data and insight concerning shock hardening and the spallation response of materials subjected to square-topped shock-wave loading profiles. Less quantitative data have been gathered on the effect of direct, in-contact, high explosive (HE)-driven Taylor wave (or triangular-wave) loading profile shock loading on the shock hardening, damage evolution, or spallation response of materials. Explosive loading induces an impulse dubbed a 'Taylor Wave'. This is a significantly different loading history than that achieved by a square-topped impulse in terms of both the pulse duration at a fixed peak pressure, and a different unloading strain rate from the peak Hugoniot state achieved. The goal of this research is to quantify the influence of shockwave obliquity on the spallation response of copper and tantalum by subjecting plates of each material to HE-driven sweeping detonation-wave loading and quantify both the wave propagation and the post-mortem damage evolution. This talk will summarize our current understanding of damage evolution during sweeping detonation-wave spallation loading in Cu and Ta and show comparisons to modeling simulations. The spallation responses of Cu and Ta are both shown to be critically dependent on the shockwave profile and the stress-state of the shock. Based on variations in the specifics of the shock drive (pulse shape, peak stress, shock obliquity) and sample geometry in Cu and Ta, 'spall strength' varies by over a factor of two and the details of the mechanisms of the damage evolution is seen to vary. Simplistic models of spallation, such as P{sub min} based on 1-D square-top shock data lack the physics to capture the influence of kinetics on damage evolution such as that operative during sweeping detonation loading. Such considerations are important for the development of predictive models of damage evolution and spallation in metals and alloys.

Gray, George T [Los Alamos National Laboratory

2010-12-14T23:59:59.000Z

360

A Critical Examination of the Adaptive Response for Cytogenetic Damagein Human Cells, and Insights into the Adaptive Response Mechanism  

NLE Websites -- All DOE Office Websites (Extended Search)

Critical Examination of the Adaptive Response for Cytogenetic Damage Critical Examination of the Adaptive Response for Cytogenetic Damage in Human Cells, and Insights into the Adaptive Response Mechanism Björn E. Rydberg, Torsten Groesser, Antoine Snijders, Kelly Trego, Ju Han, Do Yup Lee, Bahram Parvin, Trent Northen, Andrew J. Wyrobek, and Priscilla K. Cooper Berkeley Lab SFA P.I.: Gary Karpen Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 Goal: Task 1 of the Berkeley Lab SFA is designed to identify adaptive response (AR) mechanisms that may affect risk of developing radiation-induced cancer and to assess the linearity with dose of processes that influence mammary gland carcinogenesis. We use both in vitro and in vivo experimental systems in a parallelogram strategy. Our human cell culture

Note: This page contains sample records for the topic "dna damage response" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Electronic transport and localization in short and long DNA  

E-Print Network (OSTI)

The question of whether DNA conducts electric charges is intriguing to physicists and biologists alike. The suggestion that electron transfer/transport in DNA might be biologically important has triggered a series of experimental and theoretical investigations. Here, we review recent theoretical progress by concentrating on quantum-chemical, molecular dynamics-based approaches to short DNA strands and physics-motivated tight-binding transport studies of long or even complete DNA sequences. In both cases, we observe small, but significant differences between specific DNA sequences such as periodic repetitions and aperiodic sequences of AT bases, lambda-DNA, centromeric DNA, promoter sequences as well as random-ATGC DNA.

H. Wang; R. Marsh; J. P. Lewis; R. A. Roemer

2005-11-04T23:59:59.000Z

362

Low-cost, Rapid DNA Sequencing Technique - Energy Innovation Portal  

Description Sequencing DNA is crucial for future breakthroughs in biological and biomedical research. ... DNA sequencing for medical applications has been restricted ...

363

NREL: Fleet Test and Evaluation - Fleet DNA: Vehicle Drive Cycle...  

NLE Websites -- All DOE Office Websites (Extended Search)

Fleet DNA Project graphic depicting a trail of data emerging from trucks. Fleet DNA helps vehicle manufacturers and fleet managers understand the broad operational range for many...

364

Computational Challenges in Simulating Large DNA over Long Times  

Science Conference Proceedings (OSTI)

Simulating DNAs dynamics requires a sophisticated array of algorithms appropriate for DNAs impressive spectrum of spatial and temporal levels. The authors describe computational challenges

Tamar Schlick; Daniel A. Beard; Jing Huang; Daniel A. Strahs; Xiaoliang Qian

2000-01-01T23:59:59.000Z

365

The Initiation of Bacterial DNA Replication  

NLE Websites -- All DOE Office Websites (Extended Search)

The Initiation of Bacterial DNA Replication Print The Initiation of Bacterial DNA Replication Print For the first time, scientists have determined the structure of the initiator of bacterial DNA replication. It is already known that such replication is controlled by a protein known as DnaA, a member of the AAA+ superfamily of ATPases. What has now been discovered is that the core of the initiator is not the closed-ring structure expected for this system. Instead, DnaA forms an open right-handed helix. In addition, the architecture indicates that this AAA+ superhelix will wrap coils of the DNA around its exterior, causing the DNA double helix to deform as a first step in the separation and unwinding of its strands. Eukaryotic and archaeal initiators also have the structural elements that promote open-helix formation, indicating that a spiral, open-ring AAA+ assembly is a conserved element from a common evolutionary ancestor of Archaea, Bacteria, and Eukarya.

366

The Initiation of Bacterial DNA Replication  

NLE Websites -- All DOE Office Websites (Extended Search)

The Initiation of Bacterial DNA Replication Print The Initiation of Bacterial DNA Replication Print For the first time, scientists have determined the structure of the initiator of bacterial DNA replication. It is already known that such replication is controlled by a protein known as DnaA, a member of the AAA+ superfamily of ATPases. What has now been discovered is that the core of the initiator is not the closed-ring structure expected for this system. Instead, DnaA forms an open right-handed helix. In addition, the architecture indicates that this AAA+ superhelix will wrap coils of the DNA around its exterior, causing the DNA double helix to deform as a first step in the separation and unwinding of its strands. Eukaryotic and archaeal initiators also have the structural elements that promote open-helix formation, indicating that a spiral, open-ring AAA+ assembly is a conserved element from a common evolutionary ancestor of Archaea, Bacteria, and Eukarya.

367

CHRONIC CONSUMPTION OF ETHANOL LEADS TO SUBSTANTIAL CELL DAMAGE IN CULTURED RAT ASTROCYTES IN CONDITIONS PROMOTING ACETALDEHYDE ACCUMULATION  

E-Print Network (OSTI)

Abstract Aims: This study aimed at comparing the cerebral cytotoxicity of ethanol and its main metabolite acetaldehyde after acute or chronic exposures of rat astrocytes in primary culture. Methods: Cytotoxicity was evaluated on the cell reduction of viability (MTT reduction test) and on the characterization of DNA damage by single cell gel electrophoresis (or comet assay). Results: Changes in astrocyte survival and in DNA integrity only occurred when the astrocytes were chronically exposed to ethanol (20 mM; 3, 6 or 9 days). On the other hand, viability and DNA integrity were deeply affected by acute exposure to acetaldehyde. Both effects were dependent on the concentration of acetaldehyde. The cytotoxic effect of acetaldehyde was also indirectly evaluated after modifications of the normal ethanol metabolism by the use of different inducers or inhibitors. In presence of ethanol, the concomitant induction of catalase (i.e. by glucose oxidase) and inhibition of aldehyde dehydrogenase (i.e. by methylene blue) led to acetaldehyde accumulation within cells. It was followed by both a reduction in viability and a substantial increase in DNA strand breaks. Conclusions: These data were thus consistent with a possible predominant role of acetaldehyde during brain ethanol metabolism. On the other hand, the effects observed after AMT could also suggest a possible direct ethanol effect and a role for free radical attacks. These data were thus consistent with a possible predominant role of acetaldehyde during brain ethanol metabolism. On the other hand, the effects observed after AMT could also suggest a possible direct ethanol effect and a role for free radical attacks.

N. Signorini-allibe; B. Gonthier; F. Lamarche; H. Eysseric; L. Barret

2005-01-01T23:59:59.000Z

368

Method of quantitating dsDNA  

DOE Patents (OSTI)

A method for quantitating dsDNA in an aqueous sample solution containing an unknown amount of dsDNA. A first aqueous test solution containing a known amount of a fluorescent dye-dsDNA complex and at least one fluorescence-attenutating contaminant is prepared. The fluorescence intensity of the test solution is measured. The first test solution is diluted by a known amount to provide a second test solution having a known concentration of dsDNA. The fluorescence intensity of the second test solution is measured. Additional diluted test solutions are similarly prepared until a sufficiently dilute test solution having a known amount of dsDNA is prepared that has a fluorescence intensity that is not attenuated upon further dilution. The value of the maximum absorbance of this solution between 200-900 nanometers (nm), referred to herein as the threshold absorbance, is measured. A sample solution having an unknown amount of dsDNA and an absorbance identical to that of the sufficiently dilute test solution at the same chosen wavelength is prepared. Dye is then added to the sample solution to form the fluorescent dye-dsDNA-complex, after which the fluorescence intensity of the sample solution is measured and the quantity of dsDNA in the sample solution is determined. Once the threshold absorbance of a sample solution obtained from a particular environment has been determined, any similarly prepared sample solution taken from a similar environment and having the same value for the threshold absorbance can be quantified for dsDNA by adding a large excess of dye to the sample solution and measuring its fluorescence intensity.

Stark, Peter C. (Los Alamos, NM); Kuske, Cheryl R. (Los Alamos, NM); Mullen, Kenneth I. (Los Alamos, NM)

2002-01-01T23:59:59.000Z

369

Torque determination on DNA with magnetic tweezers  

E-Print Network (OSTI)

We deduced the torque applied on a single stretched and twisted DNA by integrating with respect to force the change in the molecule's extension as it is coiled. While consistent with previous direct measurements of the torque at high forces (F>1 pN) this method, which is simple and does not require a sophisticated set-up, allows for lower force estimates. We used this approach to deduce the effective torsional modulus of DNA, which decreases with force and to estimate the buckling torque of DNA as a function of force in various salt conditions.

Francesco Mosconi; Jean-Franois Allemand; David Bensimon; Vincent Croquette

2008-09-03T23:59:59.000Z

370

Chemistry and Biology of Aflatoxin-DNA Adducts  

Science Conference Proceedings (OSTI)

Aspergillus flavus is a fungal contaminant of stored rice, wheat, corn, and other grainstuffs, and peanuts. This is of concern to human health because it produces the mycotoxin aflatoxin B{sub 1} (AFB{sub 1}), which is genotoxic and is implicated in the etiology of liver cancer. AFB{sub 1} is oxidized in vivo by cytochrome P450 to form aflatoxin B{sub 1} epoxide, which forms an N7-dG adduct (AFB{sub 1}-N7-dG) in DNA. The latter rearranges to a formamidopyrimidine (AFB{sub 1}-FAPY) derivative that equilibrates between {alpha} and {beta} anomers of the deoxyribose. In DNA, both the AFB{sub 1}-N7-dG and AFB{sub 1}-{beta}-FAPY adducts intercalate above the 5'-face of the damaged guanine. Each produces G {yields} T transversions in Escherichia coli, but the AFB{sub 1}-{beta}-FAPY adduct is more mutagenic. The Sulfolobus solfataricus P2 DNA polymerase IV (Dpo4) provides a model for understanding error-prone bypass of the AFB{sub 1}-N7-dG and AFB{sub 1}-{beta}-FAPY adducts. It bypasses the AFB{sub 1}-N7-dG adduct, but it conducts error-prone replication past the AFB{sub 1}-FAPY adduct, including mis-insertion of dATP, consistent with the G {yields} T mutations characteristic of AFB{sub 1} mutagenesis in E. coli. Crystallographic analyses of a series of binary and ternary complexes with the Dpo4 polymerase revealed differing orientations of the N7-C8 bond of the AFB{sub 1}-N7-dG adduct as compared to the N{sup 5}-C8 bond in the AFB{sub 1}-{beta}-FAPY adduct, and differential accommodation of the intercalated AFB{sub 1} moieties within the active site. These may modulate AFB{sub 1} lesion bypass by this polymerase.

Stone, Michael P.; Banerjee, Surajit; Brown, Kyle L.; Egli, Martin (Vanderbilt)

2012-03-27T23:59:59.000Z

371

Structural basis for DNA bending  

Science Conference Proceedings (OSTI)

The authors report proton NMR studies on DNA oligonucleotides that contain A tracts of lengths known to produce various degrees of bending. Spectra of duplexes in the series 5{prime}-(GGCA{sub n}CGG){center dot}(CCGT{sub n}GCC) (n = 3,4,5,7,9) reveal substantial structural changes within the A{sub n}{center dot}T{sub n} tract as its length is increased. Chemical-shift comparisons show that A tracts with fewer than about seven members do not contain regions of uniform structure. Throughout the series, there is a striking monotonic relationship between the location of an A{center dot}T pair in the A tract and the relative position of its ThyH3 resonance. The direction of this chemical-shift dispersion is opposite to that expected from consideration of ring-current effects alone. This model features a substantial negative base-pair tilt, which has been suggested previously as the source of A-tract bending. In contrast, the nuclear Overhauser effect distances are inconsistent with at least one known crystallographic A-tract structure which lacks appreciable base-pair tilt.

Nadeau, J.G.; Crothers, D.M. (Yale Univ., New Haven, CT (USA))

1989-04-01T23:59:59.000Z

372

Modelling and simulations of the chemo-mechanical behaviour of leached cement-based materials: Interactions between damage and leaching  

Science Conference Proceedings (OSTI)

The assessment of the durability of cement-based materials, which could be employed in underground structures for nuclear waste disposal, requires accounting for deterioration factors, such as chemical attacks and damage, and for the interactions between these phenomena. The objective of the present paper consists in investigating the long-term behaviour of cementitious materials by simulating their response to chemical and mechanical solicitations. In a companion paper (Stora et al., submitted to Cem. Concr. Res. 2008), the implementation of a multi-scale homogenization model into an integration platform has allowed for evaluating the evolution of the mineral composition, diffusive and elastic properties inside a concrete material subjected to leaching. To complete this previous work, an orthotropic micromechanical damage model is presently developed and incorporated in this numerical platform to estimate the mechanical and diffusive properties of damaged cement-based materials. Simulations of the chemo-mechanical behaviour of leached cementitious materials are performed with the tool thus obtained and compared with available experiments. The numerical results are insightful about the interactions between damage and chemical deteriorations.

Stora, E., E-mail: stora@univ-mlv.f [Atomic Energy Commission, CEA Saclay DEN/DANS/DPC/SCCME/Laboratoire d'Etude du Comportement des Betons et des Argiles, 91191 Gif sur Yvette (France); Universite Paris-Est, Laboratoire de Modelisation et Simulation Multiechelle, FRE3160 CNRS, 5 boulevard Descartes, 77454 Marne-la-Vallee Cedex 2 (France); Bary, B. [Atomic Energy Commission, CEA Saclay DEN/DANS/DPC/SCCME/Laboratoire d'Etude du Comportement des Betons et des Argiles, 91191 Gif sur Yvette (France); He, Q.-C. [Universite Paris-Est, Laboratoire de Modelisation et Simulation Multiechelle, FRE3160 CNRS, 5 boulevard Descartes, 77454 Marne-la-Vallee Cedex 2 (France); Deville, E.; Montarnal, P. [CEA Saclay DEN/DANS/DM2S/SFME/MTMS, 91191 Gif sur Yvette (France)

2010-08-15T23:59:59.000Z

373

Benzene-derived N2-(4-hydroxyphenyl)-deoxyguanosine adduct: UvrABC incision and its conformation in DNA  

DOE Green Energy (OSTI)

Benzene, a ubiquitous human carcinogen, forms DNA adducts through its metabolites such as p-benzoquinone (p-BQ) and hydroquinone (HQ). N(2)-(4-Hydroxyphenyl)-2'-deoxyguanosine (N(2)-4-HOPh-dG) is the principal adduct identified in vivo by (32)P-postlabeling in cells or animals treated with p-BQ or HQ. To study its effect on repair specificity and replication fidelity, we recently synthesized defined oligonucleotides containing a site-specific adduct using phosphoramidite chemistry. We here report the repair of this adduct by Escherichia coli UvrABC complex, which performs the initial damage recognition and incision steps in the nucleotide excision repair (NER) pathway. We first showed that the p-BQ-treated plasmid was efficiently cleaved by the complex, indicating the formation of DNA lesions that are substrates for NER. Using a 40-mer substrate, we found that UvrABC incises the DNA strand containing N(2)-4-HOPh-dG in a dose- and time-dependent manner. The specificity of such repair was also compared with that of DNA glycosylases and damage-specific endonucleases of E. coli, both of which were found to have no detectable activity toward N(2)-4-HOPh-dG. To understand why this adduct is specifically recognized and processed by UvrABC, molecular modeling studies were performed. Analysis of molecular dynamics trajectories showed that stable G:C-like hydrogen bonding patterns of all three Watson-Crick hydrogen bonds are present within the N(2)-4-HOPh-G:C base pair, with the hydroxyphenyl ring at an almost planar position. In addition, N(2)-4-HOPh-dG has a tendency to form more stable stacking interactions than a normal G in B-type DNA. These conformational properties may be critical in differential recognition of this adduct by specific repair enzymes.

Hang, Bo; Rodriguez, Ben; Yang, Yanu; Guliaev, Anton B.; Chenna, Ahmed

2010-06-14T23:59:59.000Z

374

Mechanisms for microvascular damage induced by ultrasound-activated microbubbles  

Science Conference Proceedings (OSTI)

To provide insight into the mechanisms of microvascular damage induced by ultrasound-activated microbubbles, experimental studies were performed to correlate microvascular damage to the dynamics of bubble-vessel interactions. High-speed photomicrography was used to record single microbubbles interacting with microvessels in ex vivo tissue, under the exposure of short ultrasound pulses with a center frequency of 1 MHz and peak negative pressures (PNP) ranging from 0.8-4 MPa. Vascular damage associated with observed bubble-vessel interactions was either indicated directly by microbubble extravasation or examined by transmission electron microscopy (TEM) analyses. As observed previously, the high-speed images revealed that ultrasound-activated microbubbles could cause distention and invagination of adjacent vessel walls, and could form liquid jets in microvessels. Vessel distention, invagination, and liquid jets were associated with the damage of microvessels whose diameters were smaller than those of maximally expanded microbubbles. However, vessel invagination appeared to be the dominant mechanism for the damage of relative large microvessels.

Chen Hong; Brayman, Andrew A.; Evan, Andrew P.; Matula, Thomas J. [Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA (United States); Department of Anatomy and Cell Biology and Medicine, Indiana University School of Medicine, Indianapolis (United States); Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA (United States)

2012-10-03T23:59:59.000Z

375

Length-scale Effects in Cascade Damage Production in Iron  

SciTech Connect

Molecular dynamics simulations provide an atomistic description of the processes that control primary radiation damage formation in atomic displacement cascades. An extensive database of simulations describing cascade damage production in single crystal iron has been compiled using a modified version of the interatomic potential developed by Finnis and Sinclair. This same potential has been used to investigate primary damage formation in nanocrystalline iron in order to have a direct comparison with the single crystal results. A statistically significant number of simulations were carried out at cascade energies of 10 keV and 20 keV and temperatures of 100 and 600K to make this comparison. The results demonstrate a significant influence of nearby grain boundaries as a sink for mobile defects during the cascade cooling phase. This alters the residual primary damage that survives the cascade event. Compared to single crystal, substantially fewer interstitials survive in the nanograined iron, while the number of surviving vacancies is similar or slightly greater than the single crystal result. The fraction of the surviving interstitials contained in clusters is also reduced. The asymmetry in the survival of the two types of point defects is likely to alter damage accumulation at longer times.

Stoller, Roger E [ORNL; Osetskiy, Yury N [ORNL; Kamenski, Paul J [ORNL

2009-01-01T23:59:59.000Z

376

Properly designed underbalanced drilling fluids can limit formation damage  

Science Conference Proceedings (OSTI)

Drilling fluids for underbalanced operations require careful design and testing to ensure they do not damage sensitive formations. In addition to hole cleaning and lubrication functions, these fluids may be needed as kill fluids during emergencies. PanCanadian Petroleum Ltd. used a systematic approach in developing and field testing a nondamaging drilling fluid. It was for use in underbalanced operations in the Glauconitic sandstone in the Westerose gas field in Alberta. A lab study was initiated to develop and test a non-damaging water-based drilling fluid for the horizontal well pilot project. The need to develop an inexpensive, nondamaging drilling fluid was previously identified during underbalanced drilling operations in the Weyburn field in southeastern Saskatchewan. A non-damaging fluid is required for hole cleaning, for lubrication of the mud motor, and for use as a kill fluid during emergencies. In addition, a nondamaging fluid is required when drilling with a conventional rig because pressure surges during connections and trips may result in the well being exposed to short periods of near balanced or overbalanced conditions. Without the protection of a filter cake, the drilling fluid will leak off into the formation, causing damage. The amount of damage is related to the rate of leak off and depth of invasion, which are directly proportional to the permeability to the fluid.

Churcher, P.L.; Yurkiw, F.J. [PanCanadian Petroleum Ltd., Calgary, Alberta (Canada); Bietz, R.F.; Bennion, D.B. [Hycal Energy Research Ltd., Calgary, Alberta (Canada)

1996-04-29T23:59:59.000Z

377

Structural Characterization of Clostridium acetobutylicum 8-Oxoguanine DNA Glycosylase in Its Apo Form and in Complex with 8-Oxodeoxyguanosine  

Science Conference Proceedings (OSTI)

DNA is subject to a multitude of oxidative damages generated by oxidizing agents from metabolism and exogenous sources and by ionizing radiation. Guanine is particularly vulnerable to oxidation, and the most common oxidative product 8-oxoguanine (8-oxoG) is the most prevalent lesion observed in DNA molecules. 8-OxoG can form a normal Watson-Crick pair with cytosine (8-oxoG:C), but it can also form a stable Hoogsteen pair with adenine (8-oxoG:A), leading to a G:C {yields} T:A transversion after replication. Fortunately, 8-oxoG is recognized and excised by either of two DNA glycosylases of the base excision repair pathway: formamidopyrimidine-DNA glycosylase and 8-oxoguanine DNA glycosylase (Ogg). While Clostridium acetobutylicum Ogg (CacOgg) DNA glycosylase can specifically recognize and remove 8-oxoG, it displays little preference for the base opposite the lesion, which is unusual for a member of the Ogg1 family. This work describes the crystal structures of CacOgg in its apo form and in complex with 8-oxo-2'-deoxyguanosine. A structural comparison between the apo form and the liganded form of the enzyme reveals a structural reorganization of the C-terminal domain upon binding of 8-oxoG, similar to that reported for human OGG1. A structural comparison of CacOgg with human OGG1, in complex with 8-oxoG containing DNA, provides a structural rationale for the lack of opposite base specificity displayed by CacOgg.

Faucher, Frdrick; Robey-Bond, Susan M.; Wallace, Susan S.; Doubli, Sylvie; (Vermont)

2009-06-30T23:59:59.000Z

378

Why DNA is a double helix  

NLE Websites -- All DOE Office Websites (Extended Search)

Guest14 Location: NA Country: NA Date: NA Question: Why is DNA in a double-helix shape? Replies: The why questions are always the worst. Why is anything the way it is? The...

379

Deoxyribose oxidation chemistry and endogenous DNA adducts  

E-Print Network (OSTI)

Endogenous and exogenous oxidants react with cellular macromolecules to generate a variety of electrophiles that react with DNA produce cytotoxic and mutagenic adducts. One source of such electrophiles is deoxyribose in ...

Zhou, Xinfeng

2006-01-01T23:59:59.000Z

380

Linear Thermodynamics of Rodlike DNA Filtration  

E-Print Network (OSTI)

Linear thermodynamics transportation theory is employed to study filtration of rodlike DNA molecules. Using the repeated nanoarray consisting of alternate deep and shallow regions, it is demonstrated that the complex ...

Li, Zirui

Note: This page contains sample records for the topic "dna damage response" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Everything a Trial Judge Needs to Know about DNA (in a ...  

Science Conference Proceedings (OSTI)

... evidence Paternity testing -- identifying father Missing persons investigations Military DNA dog tag Convicted felon DNA databases ...

2013-06-25T23:59:59.000Z

382

Exemplary Hurricane Damage Cleanup Earns Petroleum Reserve Coveted  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Exemplary Hurricane Damage Cleanup Earns Petroleum Reserve Coveted Exemplary Hurricane Damage Cleanup Earns Petroleum Reserve Coveted Environmental Award Exemplary Hurricane Damage Cleanup Earns Petroleum Reserve Coveted Environmental Award April 22, 2010 - 1:00pm Addthis Washington, DC - An exceptional waste management project at a Texas Strategic Petroleum Reserve (SPR) site following Hurricane Ike in 2008 has won a DOE Environmental Sustainability (EStar) Award for Waste/Pollution Prevention. The award recognizes the SPR Storm Recovery Debris Waste Management Project at the Big Hill storage complex near Beaumont, Texas, which was heavily impacted by Hurricane Ike in September 2008. Selected annually by an independent panel of judges, EStar awards recognize environmental sustainability projects and programs that reduce risks and impacts, protect

383

Effects of ballistic damage on the dynamics of composite driveshafts  

E-Print Network (OSTI)

The objective of this research program is to study the dynamics of a composite driveshaft before and after ballistic damage is incurred. Driveshafts are tested under static and dynamic loads to obtain material, mechanical, and vibrational characteristics. In the dynamic tests, driveshafts with and without ballistic damage are observed to determine the critical speeds. The torsional modulus, the longitudinal modulus, and Poisson's ratio are determined from the static tests. Computational models are used to perform parametric studies and to complement the experimental program. Numerical simulations incorporate both beam and shell theory into the analysis. Additionally, non-destructive evaluation (NDE) was used to help determine the extent of the damage caused by the projectile.

Ayers, Thomas Ray

1993-01-01T23:59:59.000Z

384

Multiple tag labeling method for DNA sequencing  

DOE Patents (OSTI)

A DNA sequencing method described which uses single lane or channel electrophoresis. Sequencing fragments are separated in said lane and detected using a laser-excited, confocal fluorescence scanner. Each set of DNA sequencing fragments is separated in the same lane and then distinguished using a binary coding scheme employing only two different fluorescent labels. Also described is a method of using radio-isotope labels.

Mathies, Richard A. (Contra Costa County, CA); Huang, Xiaohua C. (Mt. View, CA); Quesada, Mark A. (San Francisco, CA)

1995-01-01T23:59:59.000Z

385

A simplified implementation of a gradient-enhanced damage model with transient length scale effects  

Science Conference Proceedings (OSTI)

Gradient-enhanced damage models with constant gradient activity suffer from spurious damage growth at high deformation levels. This issue was resolved by Geers et al. (Comput Methods Appl Mech Eng 160(1---2):133---153, 1998) by expressing the gradient ... Keywords: Continuum damage mechanics, Gradient-enhanced damage models, Regularized media, Transient internal length scale

S. Saroukhani; R. Vafadari; A. Simone

2013-06-01T23:59:59.000Z

386

Assessing Vulnerabilities, Risks, and Consequences of Damage to Critical Infrastructure  

SciTech Connect

Since the publication of 'Critical Foundations: Protecting America's Infrastructure,' there has been a keen understanding of the complexity, interdependencies, and shared responsibility required to protect the nation's most critical assets that are essential to our way of life. The original 5 sectors defined in 1997 have grown to 18 Critical Infrastructures and Key Resources (CIKR), which are discussed in the 2009 National Infrastructure Protection Plan (NIPP) and its supporting sector-specific plans. The NIPP provides the structure for a national program dedicated to enhanced protection and resiliency of the nation's infrastructure. Lawrence Livermore National Laboratory (LLNL) provides in-depth, multi-disciplinary assessments of threat, vulnerability, and consequence across all 18 sectors at scales ranging from specific facilities to infrastructures spanning multi-state regions, such as the Oil and Natural Gas (ONG) sector. Like many of the CIKR sectors, the ONG sector is comprised of production, processing, distribution, and storage of highly valuable and potentially dangerous commodities. Furthermore, there are significant interdependencies with other sectors, including transportation, communication, finance, and government. Understanding the potentially devastating consequences and collateral damage resulting from a terrorist attack or natural event is an important element of LLNL's infrastructure security programs. Our work began in the energy sector in the late 1990s and quickly expanded other critical infrastructure sectors. We have performed over 600 physical assessments with a particular emphasis on those sectors that utilize, store, or ship potentially hazardous materials and for whom cyber security is important. The success of our approach is based on building awareness of vulnerabilities and risks and working directly with industry partners to collectively advance infrastructure protection. This approach consists of three phases: The Pre-Assessment Phase brings together infrastructure owners and operators to identify critical assets and help the team create a structured information request. During this phase, we gain information about the critical assets from those who are most familiar with operations and interdependencies, making the time we spend on the ground conducting the assessment much more productive and enabling the team to make actionable recommendations. The Assessment Phase analyzes 10 areas: Threat environment, cyber architecture, cyber penetration, physical security, physical penetration, operations security, policies and procedures, interdependencies, consequence analysis, and risk characterization. Each of these individual tasks uses direct and indirect data collection, site inspections, and structured and facilitated workshops to gather data. Because of the importance of understanding the cyber threat, LLNL has built both fixed and mobile cyber penetration, wireless penetration and supporting tools that can be tailored to fit customer needs. The Post-Assessment Phase brings vulnerability and risk assessments to the customer in a format that facilitates implementation of mitigation options. Often the assessment findings and recommendations are briefed and discussed with several levels of management and, if appropriate, across jurisdictional boundaries. The end result is enhanced awareness and informed protective measures. Over the last 15 years, we have continued to refine our methodology and capture lessons learned and best practices. The resulting risk and decision framework thus takes into consideration real-world constraints, including regulatory, operational, and economic realities. In addition to 'on the ground' assessments focused on mitigating vulnerabilities, we have integrated our computational and atmospheric dispersion capability with easy-to-use geo-referenced visualization tools to support emergency planning and response operations. LLNL is home to the National Atmospheric Release Advisory Center (NARAC) and the Interagency Modeling and Atmospheric Assessment Center (IMAAC). NA

Suski, N; Wuest, C

2011-02-04T23:59:59.000Z

387

Thermal annealing of laser damage precursors on fused silica surfaces  

SciTech Connect

Previous studies have identified two significant precursors of laser damage on fused silica surfaces at fluenes below {approx} 35 J/cm{sup 2}, photoactive impurities in the polishing layer and surface fractures. In the present work, isothermal heating is studied as a means of remediating the highly absorptive, defect structure associated with surface fractures. A series of Vickers indentations were applied to silica surfaces at loads between 0.5N and 10N creating fracture networks between {approx} 10{micro}m and {approx} 50{micro}m in diameter. The indentations were characterized prior to and following thermal annealing under various times and temperature conditions using confocal time-resolved photo-luminescence (CTP) imaging, and R/1 optical damage testing with 3ns, 355nm laser pulses. Significant improvements in the damage thresholds, together with corresponding reductions in CTP intensity, were observed at temperatures well below the glass transition temperature (T{sub g}). For example, the damage threshold on 05.N indentations which typically initiates at fluences <8 J/cm{sup 2} could be improved >35 J/cm{sup 2} through the use of a {approx} 750 C thermal treatment. Larger fracture networks required longer or higher temperature treatment to achieve similar results. At an annealing temperature > 1100 C, optical microscopy indicates morphological changes in some of the fracture structure of indentations, although remnants of the original fracture and significant deformation was still observed after thermal annealing. This study demonstrates the potential of using isothermal annealing as a means of improving the laser damage resistance of fused silica optical components. Similarly, it provides a means of further understanding the physics associated with optical damage and related mitigation processes.

Shen, N; Miller, P E; Bude, J D; Laurence, T A; Suratwala, T I; Steele, W A; Feit, M D; Wang, L L

2012-03-19T23:59:59.000Z

388

Thermal annealing of laser damage precursors on fused silica surfaces  

Science Conference Proceedings (OSTI)

Previous studies have identified two significant precursors of laser damage on fused silica surfaces at fluenes below {approx} 35 J/cm{sup 2}, photoactive impurities in the polishing layer and surface fractures. In the present work, isothermal heating is studied as a means of remediating the highly absorptive, defect structure associated with surface fractures. A series of Vickers indentations were applied to silica surfaces at loads between 0.5N and 10N creating fracture networks between {approx} 10{micro}m and {approx} 50{micro}m in diameter. The indentations were characterized prior to and following thermal annealing under various times and temperature conditions using confocal time-resolved photo-luminescence (CTP) imaging, and R/1 optical damage testing with 3ns, 355nm laser pulses. Significant improvements in the damage thresholds, together with corresponding reductions in CTP intensity, were observed at temperatures well below the glass transition temperature (T{sub g}). For example, the damage threshold on 05.N indentations which typically initiates at fluences 35 J/cm{sup 2} through the use of a {approx} 750 C thermal treatment. Larger fracture networks required longer or higher temperature treatment to achieve similar results. At an annealing temperature > 1100 C, optical microscopy indicates morphological changes in some of the fracture structure of indentations, although remnants of the original fracture and significant deformation was still observed after thermal annealing. This study demonstrates the potential of using isothermal annealing as a means of improving the laser damage resistance of fused silica optical components. Similarly, it provides a means of further understanding the physics associated with optical damage and related mitigation processes.

Shen, N; Miller, P E; Bude, J D; Laurence, T A; Suratwala, T I; Steele, W A; Feit, M D; Wang, L L

2012-03-19T23:59:59.000Z

389

Oligonucleotide and Long Polymeric DNA Encoding  

Science Conference Proceedings (OSTI)

This report summarizes the work done at Lawrence Livermore National Laboratory for the Oligonucleotide and Long Polymeric DNA Encoding project, part of the Microelectronic Bioprocesses Program at DARPA. The goal of the project was to develop a process by which long (circa 10,000 base-pair) synthetic DNA molecules could be synthesized in a timely and economic manner. During construction of the long molecule, errors in DNA sequence occur during hybridization and/or the subsequent enzymatic process. The work done on this project has resulted in a novel synthesis scheme that we call the parallel pyramid synthesis protocol, the development of a suit of computational tools to minimize and quantify errors in the synthesized DNA sequence, and experimental proof of this technique. The modeling consists of three interrelated modules: the bioinformatics code which determines the specifics of parallel pyramid synthesis for a given chain of long DNA, the thermodynamics code which tracks the products of DNA hybridization and polymerase extension during the later steps in the process, and the kinetics model which examines the temporal and spatial processes during one thermocycle. Most importantly, we conducted the first successful syntheses of a gene using small starting oligomers (tetramers). The synthesized sequence, 813 base pairs long, contained a 725 base pair gene, modified green fluorescent protein (mGFP), which has been shown to be a functional gene by cloning into cells and observing its green fluorescent product.

Miller, E; Mariella Jr., R P; Christian, A T; Gardner, S N; Williams, J M

2003-11-24T23:59:59.000Z

390

BDS Thin Film UV Antireflection Laser Damage Competition  

Science Conference Proceedings (OSTI)

UV antireflection coatings are a challenging coating for high power laser applications as exemplified by the use of uncoated Brewster's windows in laser cavities. In order to understand the current laser resistance of UV AR coatings in the industrial and university sectors, a double blind laser damage competition was performed. The coatings have a maximum reflectance of 0.5% at 355 nm at normal incidence. Damage testing will be performed using the raster scan method with a 7.5 ns pulse length on a single testing facility to facilitate direct comparisons. In addition to the laser resistance results, details of deposition processes and coating materials will also be shared.

Stolz, C J

2010-10-26T23:59:59.000Z

391

Biological Damage due to Photospheric, Chromospheric and Flare Radiation in the Environments of Main-Sequence Stars  

E-Print Network (OSTI)

We explore the biological damage initiated in the environments of F, G, K, and M-type main-sequence stars due to photospheric, chromospheric and flare radiation. The amount of chromospheric radiation is, in a statistical sense, directly coupled to the stellar age as well as the presence of significant stellar magnetic fields and dynamo activity. With respect to photospheric radiation, we also consider detailed synthetic models, taking into account millions or hundred of millions of lines for atoms and molecules. Chromospheric UV radiation is increased in young stars in regard to all stellar spectral types. Flare activity is most pronounced in K and M-type stars, which also has the potential of stripping the planetary atmospheres of close-in planets, including planets located in the stellar habitable zone. For our studies, we take DNA as a proxy for carbon-based macromolecules, guided by the paradigm that carbon might constitute the biochemical centerpiece of extraterrestrial life forms. Planetary atmospheric ...

Cuntz, M; Kurucz, R L

2009-01-01T23:59:59.000Z

392

Landowner and permit-holder perceptions of wildlife damage around the Idaho National Engineering and Environmental Laboratory. A survey of INEEL neighbors about elk, mule deer, pronghorn antelope, and depredation  

Science Conference Proceedings (OSTI)

Property-owners (N = 220) around the Idaho National Engineering and Environmental Laboratory (INEEL) in southeastern Idaho were surveyed about depredation, control methods and economic issues related to use of the area by elk (Cervus elaphus), mule deer (Odocoileus hemionus), and pronghorn antelope (Antilocapra americana). Depredation was defined as damage to privately-owned crops, forage, and fences and irrigation equipment by these animals. The focus on the three ungulate species was prompted by concerns that elk, which had recolonized the INEEL since 1984, were responsible for an inordinate amount of unprecedented damage to agricultural operations. As the INEEL is a US Department of Energy (DOE) reserve with little public hunting access, there have been calls for removal of elk from this land. This study`s objective was to quantify the wildlife damage occurring on agricultural operations adjacent to the INEEL and to characterize the damage attributed to each big game species. Responses from 70.2% of the target population indicate an evenness of opinion, by which the authors mean that various opinions were represented equitably, toward these animals and wildlife damage Total estimated wildlife damage in 1996 was between $140,000 and $180,000 It was attributed foremost to elk, although pronghorn antelope were viewed nearly as damaging. Respondents placed high values in big game animals and wished to see them continue to inhabit these lands. For managing depredation, adjusting hunting seasons was preferred.

Roush, D.E. Jr. [Environmental Science and Research Foundation, Inc., Idaho Falls, ID (United States); Beaver, D.E. [Univ. of Idaho, Moscow, ID (United States). Coll. of Forestry, Wildlife, and Range Sciences

1998-06-01T23:59:59.000Z

393

Response to Warnings during the 3 May 1999 Oklahoma City Tornado: Reasons and Relative Injury Rates  

Science Conference Proceedings (OSTI)

Residents of homes that sustained F4 or F5 damage in the deadliest of the 3 May 1999 tornadoes were surveyed to determine their responses to the tornado warning, reasons for their responses, and relative injury rates. There were 190 people in 65 ...

Barbara Hammer; Thomas W. Schmidlin

2002-06-01T23:59:59.000Z

394

CORRELATION OF DNA METHYLATION WITH MERCURY CONTAMINATION IN MARINE ORGANISMS: A CASE STUDY OF NOAA MUSSEL WATCH TISSUE SAMPLES  

E-Print Network (OSTI)

American oysters (Crassostrea virginica) obtained from the NOAA Mussel Watch program were screened for DNA methylation, a type of epigenetic response to stressors. Oysters were collected from sites in the Gulf of Mexico having high mercury contamination (measured by NOAA) and from sites with little to no measurable mercury. Assessment of anthropogenic stressors such as mercury in the coastal environment has traditionally relied upon species diversity indices or assays to determine lethal doses. However, these indices fail to examine sub-lethal impacts such as gene expression. A global DNA methylation kit, recently introduced by Sigma-Aldrich, was used to spectrophotometrically compare the degree of methylation in DNA extracted from contaminated oysters and non-contaminated oysters. DNA methylation was higher in oysters from pristine sites than in oysters from contaminated sites.

Brinkmeyer, Robin; Taylor, Robert; Germ, Kaylyn E.

2011-08-04T23:59:59.000Z

395

Power Burst Facility (PBF) severe fuel damage test 1-4 test results report  

DOE Green Energy (OSTI)

A comprehensive evaluation of the Severe Fuel Damage (SFD) Test 1-4 performed in the Power Burst Facility (PBF) at the Idaho National Engineering Laboratory is presented. Test SFD 1-4 was the fourth and final test in an internationally sponsored light water reactor severe accident research program, initiated by the US Nuclear Regulatory Commission. The overall technical objective of the test was to contribute to the understanding of fuel and control rod behavior, aerosol and hydrogen generation, and fission product release and transport during a high-temperature, severe fuel damage transient. A test bundle, comprised of 26 previously irradiated (36,000 MWd/MtU) pressurized water-reactor-type fuel rods, 2 fresh instrumented fuel rods, and 4 silver-indium-cadmium control rods, was surrounded by an insulating shroud and contained in a pressurized in-pile tube. The experiment consisted of a 1.3-h transient at a coolant pressure of 6.95 MPa in which the inlet coolant flow to the bundle was reduced to 0.6 g/s while the bundle fission power was gradually increased until dryout, heatup, cladding rupture, and oxidation occurred. With sustained fission power and heat from oxidation, temperatures continued to rise rapidly, resulting in zircaloy and control rod absorber alloy melting, fuel liquefaction, material relocation, and the release of hydrogen, aerosols, and fission products. The transient was terminated over a 2100-s time span by slowly reducing the reactor power and cooling the damaged bundle with argon gas. A description and evaluation of the major phenomena, based upon the response of on-line instrumentation, analysis of fission product and aerosol data, postirradiation examination of the fuel bundle, and calculations using the SCDAP/RELAP5 computer code, are presented. 40 refs., 160 figs., 31 tabs.

Petti, D.A.; Martinson, Z.R.; Hobbins, R.R.; Allison, C.M.; Carlson, E.R.; Hagrman, D.L.; Cheng, T.C.; Hartwell, J.K.; Vinjamuri, K.; Seifken, L.J.

1989-04-01T23:59:59.000Z

396

PBF (Power Burst Facility) severe fuel damage test 1--3 test results report  

Science Conference Proceedings (OSTI)

A comprehensive evaluation of the Severe Fuel Damage (SFD) Test 1--3 performed in the Power Burst Facility (PBF) at the Idaho National Engineering Laboratory is presented. Test SFD 1--3 was the third test in an internationally sponsored light water reactor severe accident research program, initiated by the US Nuclear Regulatory Commission. The overall technical objective of the test was to contribute to the understanding of fuel rod behavior, hydrogen generation, and fission product release and transport during a high-temperature, severe fuel damage transient. A test bundle, comprised of 26 previously irradiated (38,000 MWd/tU) pressurized water reactor-type fuel rods, 2 fresh instrumented fuel rods, and 4 empty zircaloy guide tubes, was surrounded by an insulating shroud and contained in a pressurized in-pile tube. The experiment consisted of a 1-h transient at a nominal coolant pressure of 6.85 MPa in which the inlet coolant flow to the bundle was reduced to 0.6 g/s while the bundle fission power was gradually increased until dryout, heatup, cladding rupture, and oxidation occurred. With sustained fission power and heat from oxidation, temperatures continued to rise rapidly, resulting in zircaloy melting, fuel liquefaction, material relocation, and the release of hydrogen, aerosols, and fission products. The transient was terminated over a 1340-s time span by slowly reducing the reactor power and cooling the damaged bundle with argon gas. A description and evaluation of the major phenomena, based upon the response of online instrumentation, analysis of fission product data, postirradiation examination of the fuel bundle, and calculations using the SCDAP/RELAP5 computer code, are presented. 34 refs., 241 figs., 51 tabs.

Martinson, Z.R.; Gasparini, M.; Hobbins, R.R.; Petti, D.A.; Allison, C.M.; Hohorst, J.K.; Hagrman, D.L.; Vinjamuri, K. (EG and G Idaho, Inc., Idaho Falls, ID (USA))

1989-10-01T23:59:59.000Z

397

Structure of the intact PPAR-[gamma]?RXR-[alpha] nuclear receptor complex on DNA  

SciTech Connect

Nuclear receptors are multi-domain transcription factors that bind to DNA elements from which they regulate gene expression. The peroxisome proliferator-activated receptors (PPARs) form heterodimers with the retinoid X receptor (RXR), and PPAR-{gamma} has been intensively studied as a drug target because of its link to insulin sensitization. Previous structural studies have focused on isolated DNA or ligand-binding segments, with no demonstration of how multiple domains cooperate to modulate receptor properties. Here we present structures of intact PPAR-{gamma} and RXR-{alpha} as a heterodimer bound to DNA, ligands and coactivator peptides. PPAR-{gamma} and RXR-{alpha} form a non-symmetric complex, allowing the ligand-binding domain (LBD) of PPAR-{gamma} to contact multiple domains in both proteins. Three interfaces link PPAR-{gamma} and RXR-{alpha}, including some that are DNA dependent. The PPAR-{gamma} LBD cooperates with both DNA-binding domains (DBDs) to enhance response-element binding. The A/B segments are highly dynamic, lacking folded substructures despite their gene-activation properties.

Chandra, Vikas; Huang, Pengxiang; Hamuro, Yoshitomo; Raghuram, Srilatha; Wang, Yongjun; Burris, Thomas P.; Rastinejad, Fraydoon (Penn. Bio.); (ExSAR); (UV)

2009-01-09T23:59:59.000Z

398

When DNA Needs to Stand Up and Be Counted  

NLE Websites -- All DOE Office Websites (Extended Search)

When DNA Needs to Stand Up and Be Counted Print When DNA Needs to Stand Up and Be Counted Print DNA microarrays are small metal, glass, or silicon chips covered with patterns of short single-stranded DNA (ssDNA). These "DNA chips" are revolutionizing biotechnology, allowing scientists to identify and count many DNA sequences simultaneously. They are the enabling technology for genomic-based medicine and are a critical component of advanced diagnostic systems for medical and homeland security applications. Like digital chips, DNA chips are parallel, accurate, fast, and small. These advantages, however, can only be realized if the fragile biomolecules survive the attachment process intact. Furthermore, biomolecules must be properly oriented to perform their biological function. In other words, the DNA literally must stand up to be counted. Understanding both the attachment and orientation of DNA on gold surfaces was the goal of recent experiments performed at ALS Beamline 8.0.1 by an international collaboration of scientists.

399

When DNA Needs to Stand Up and Be Counted  

NLE Websites -- All DOE Office Websites (Extended Search)

When DNA Needs to Stand Up and Be Counted Print When DNA Needs to Stand Up and Be Counted Print DNA microarrays are small metal, glass, or silicon chips covered with patterns of short single-stranded DNA (ssDNA). These "DNA chips" are revolutionizing biotechnology, allowing scientists to identify and count many DNA sequences simultaneously. They are the enabling technology for genomic-based medicine and are a critical component of advanced diagnostic systems for medical and homeland security applications. Like digital chips, DNA chips are parallel, accurate, fast, and small. These advantages, however, can only be realized if the fragile biomolecules survive the attachment process intact. Furthermore, biomolecules must be properly oriented to perform their biological function. In other words, the DNA literally must stand up to be counted. Understanding both the attachment and orientation of DNA on gold surfaces was the goal of recent experiments performed at ALS Beamline 8.0.1 by an international collaboration of scientists.

400

Role of retinoic acid in the modulation of benzo(a)pyrene-DNA adducts in human hepatoma cells: Implications for cancer prevention  

SciTech Connect

Carcinogen-DNA adducts could lead to mutations in critical genes, eventually resulting in cancer. Many studies have shown that retinoic acid (RA) plays an important role in inducing cell apoptosis. Here we have tested the hypothesis that levels of carcinogen-DNA adducts can be diminished by DNA repair and/or by eliminating damaged cells through apoptosis. Our results showed that the levels of total DNA adducts in HepG2 cells treated with benzo(a)pyrene (BP, 2 {mu}M) + RA (1 {mu}M) were significantly reduced compared to those treated with BP only (P = 0.038). In order to understand the mechanism of attenuation of DNA adducts, further experiments were performed. Cells were treated with BP (4 {mu}M) for 24 h to initiate DNA adduct formation, following which the medium containing BP was removed, and fresh medium containing 1 {mu}M RA was added. The cells were harvested 24 h after RA treatment. Interestingly, the levels of total DNA adducts were lower in the BP/RA group (390 {+-} 34) than those in the BP/DMSO group (544 {+-} 33), P = 0.032. Analysis of cell apoptosis showed an increase in BP + RA group, compared to BP or RA only groups. Our results also indicated that attenuation of BP-DNA adducts by RA was not primarily due to its effects on CYP1A1 expression. In conclusion, our results suggest a mechanistic link between cellular apoptosis and DNA adduct formation, phenomena that play important roles in BP-mediated carcinogenesis. Furthermore, these results help understand the mechanisms of carcinogenesis, especially in relation to the chemopreventive properties of nutritional apoptosis inducers.

Zhou Guodong, E-mail: gzhou@ibt.tamhsc.edu [Department of Environmental and Occupational Health, School of Rural Public Health, Texas A and M University System, College Station, Texas (United States); Institute of Biosciences and Technology, Texas A and M University System, Houston, Texas (United States); Richardson, Molly [Department of Environmental and Occupational Health, School of Rural Public Health, Texas A and M University System, College Station, Texas (United States); Fazili, Inayat S. [Department of Pediatrics, Baylor College of Medicine, Houston, Texas (United States); Wang, Jianbo [Institute of Biosciences and Technology, Texas A and M University System, Houston, Texas (United States); Donnelly, Kirby C. [Department of Environmental and Occupational Health, School of Rural Public Health, Texas A and M University System, College Station, Texas (United States); Wang Fen; Amendt, Brad [Institute of Biosciences and Technology, Texas A and M University System, Houston, Texas (United States); Moorthy, Bhagavatula [Department of Pediatrics, Baylor College of Medicine, Houston, Texas (United States)

2010-12-15T23:59:59.000Z

Note: This page contains sample records for the topic "dna damage response" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
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401

Testing wall panels for earthquake response  

SciTech Connect

As part of the structural response research program being conducted for the Nevada Operations Office of ERDA a testing program for the investigation of nonstructural wall panels subjected to racking was developed and conducted. The objectives of the testing program were to determine thresholds for damage to partitions due to horizontal adjacent story displacement in high-rise buildings and to gather data that can be used to determine the influence of nonstructural partitions on the structural response of high-rise buildings. In general, the wall panels were constructed to represent typical partitions used in high-rise building construction. Some of the panels were used for special parameter studies or for comparisons with other test programs. A specially designed testing frame simulated cyclic lateral displacement, parallel to the plane of the wall panels, that might be experienced during the response of a building to strong winds or earthquake motion. Stiffness and strength characteristics, estimates of equivalent viscous damping, and damage threshold results were obtained. The data appear to give a good approximate evaluation of the performance of non-load-bearing partitions under cyclic loading. (LCL)

Freeman, S.A.

1976-01-01T23:59:59.000Z

402

Probabilistic fatigue damage prognosis using maximum entropy approach  

E-Print Network (OSTI)

al., 1979). Therefore, fatigue damage accumulation is stochastic in nature. Several physical models, parameter estimation and future inspection and maintenance need to be carefully included for risk assessment studies have been reported to combine the information obtained from inspection with the physical model

Liu, Yongming

403

Methods for globally treating silica optics to reduce optical damage  

SciTech Connect

A method for preventing damage caused by high intensity light sources to optical components includes annealing the optical component for a predetermined period. Another method includes etching the optical component in an etchant including fluoride and bi-fluoride ions. The method also includes ultrasonically agitating the etching solution during the process followed by rinsing of the optical component in a rinse bath.

Miller, Philip Edward; Suratwala, Tayyab Ishaq; Bude, Jeffrey Devin; Shen, Nan; Steele, William Augustus; Laurence, Ted Alfred; Feit, Michael Dennis; Wong, Lana Louie

2012-11-20T23:59:59.000Z

404

Considerations for Planting Corn into Damaged Fields of Wheat  

E-Print Network (OSTI)

Many folks are still assessing the condition of wheat fields damaged by the low temperatures of the past week. In some situations, additional damage to wheat has occurred from standing water in fields due to frequent rains this winter and spring. Some growers may decide replanting damaged wheat fields to corn is a viable economic option. Some of the key considerations for doing so are described in this article. Killing the Remaining Stand of Wheat For damaged wheat fields that will be planted to corn, complete and timely control of the existing wheat is more important than if planting to soybean. Corn is more sensitive to early-season weed competition than soybean. Living wheat plants are essentially weeds and can absorb nitrogen and make it unavailable for the corn plants during the same growing season. Use of a glyphosate-based burndown program should include the use of glyphosate at 1.5 lb ae/A + 2.4-D at 1-2 pts/A. The herbicide 2,4-D is needed to control glyphosateresistant marestail which is very prevalent in southern Indiana and help with control of emerged common lambsquarter and ragweed. Apply in a spray volume of 10 to 15 GPA

Bill Johnson; Tony Vyn; Jim Camberato; Christian Krupke; Rl (bob Nielsen; Depts Of Botany; Plant Pathology

2007-01-01T23:59:59.000Z

405

Analysis of Building Damages of Paste Backfill Mining under Villages  

Science Conference Proceedings (OSTI)

In order to realize coal mining in safety without moving villages, increase coal recovery ratio, solve the conflict of mining and panel relays, the scheme of paste backfill mining under villages in Xiaotun coal mine is executed, and the surface subsidence ... Keywords: Mining under Villages, Paste Backfilling, Damage Assessment, Displacement, Deformation

Chai Hua-bin; Zou You-feng; Guo Wen-bing; Chen Jun-jie

2011-02-01T23:59:59.000Z

406

Displacement Damage in Silicon Carbide Irradiated in Fission Reactors  

SciTech Connect

Calculations are performed for displacement damage in SiC due to irradiation in the neutron environments of various types of nuclear reactors using the best available models and nuclear data. The displacement damage calculations use recently developed damage functions for SiC that are based on extensive molecular dynamics simulations of displacement events1. Displacements per atom (DPA) cross sections for SiC have been calculated as a function of neutron energy, and they are presented here in tabular form to facilitate their use as the standard measure of displacement damage for irradiated SiC. DPA cross sections averaged over the neutron energy spectrum are calculated for neutron spectra in the cores of typical commercial reactors and in the test sample irradiation regions of several materials test reactors used in both past and present irradiation testing. Particular attention is focused on a next-generation high-temperature gas-cooled pebble bed reactor, for which the high-temperature properties of silicon carbide fiber-reinforced silicon carbide composites are well suited. Calculated transmutations and activation levels in a pebble bed reactor are compared to those in other reactors.

Heinisch, Howard L.; Greenwood, Lawrence R.; Weber, William J.; Williford, Rick E.

2004-04-05T23:59:59.000Z

407

Global Warming Effects on U.S. Hurricane Damage  

Science Conference Proceedings (OSTI)

While many studies of the effects of global warming on hurricanes predict an increase in various metrics of Atlantic basin-wide activity, it is less clear that this signal will emerge from background noise in measures of hurricane damage, which ...

Kerry Emanuel

2011-10-01T23:59:59.000Z

408

Crop-Hail Damage in the Midwest Corn Belt  

Science Conference Proceedings (OSTI)

Crop-hail damage in the ten Midwest corn belt states is examined during the period 195781. Estimates of crop losses due to hail are made from hail insurance data for each state and each significant crop in the region. The crop-hail losses are ...

Harry J. Hillaker Jr.; Paul J. Waite

1985-01-01T23:59:59.000Z

409

Computational simulation of electromigration induced damage in copper interconnects  

Science Conference Proceedings (OSTI)

Current density levels are expected to increase by orders of magnitude in next generation power electronics and nanoelectronics. Electromigration which occur under high current density is the major concern for the nanoelectronics industry. Using a general ... Keywords: copper interconnects, damage mechanics, electromigration, electronics packaging reliability, thin film

Cemal Basaran; Minghui Lin; Shidong Li

2007-07-01T23:59:59.000Z

410

Strategic petroleum reserve caverns casing damage update 1997  

Science Conference Proceedings (OSTI)

Hanging casing strings are used for oil and brine transfer in the domal salt storage caverns of the Strategic Petroleum Reserve (SPR). Damage to these casings is of concern because hanging string replacement is costly and because of implications on cavern stability. Although the causes of casing damage are not always well defined, many events leading to damage are assumed to be the result of salt falls impacting the hanging strings. However, in some cases, operational aspects may be suspected. The history of damage to hanging strings is updated in this study to include the most recent events. Potential general domal and local operational and material factors that could influence the tendency for caverns to have salt falls are examined in detail. As a result of this examination, general factors, such as salt dome anomalies and crude type, and most of the operational factors, such as geometry, location and depressurizations, are not believed to be primary causes of casing damage. Further analysis is presented of the accumulation of insolubles during cavern solutioning and accumulation of salt fall material on the cavern floor. Inaccuracies in sump geometry probably make relative cavern insolubles contents uncertain. However, determination of the salt fall accumulations, which are more accurate, suggest that the caverns with the largest salt fall accumulations show the greatest number of hanging string events. There is good correlation between the accumulation rate and the number of events when the event numbers are corrected to an equivalent number for a single hanging string in a quiescent, operating cavern. The principal factor that determines the propensity for a cavern to exhibit this behavior is thought to be the effect of impurity content on the fracture behavior of salt.

Munson, D.E.; Molecke, M.A.; Neal, J.T. [and others

1998-01-01T23:59:59.000Z

411

DAMAGE TO COMMERCIAL AND INDUSTRIAL BUILDINGS EXPOSED TO NUCLEAR EFFECTS  

SciTech Connect

One equipment control building designed to be blast resistant and two each of three standardized types of metal warehouse or utility buildings were exposed to the effects of a nuclear device detonation. One of the utility buildings was frameless, with deeply corrugated wall and roof sections; a second was very largely frameless, utilizing interlocking channel sections; and in the third the aluininum-panel wall and roof covering was supported by girts and purlins, which in turn were supported by steel frames. Because of atmospheric conditions at the time of an earlier detonation in the test series, one of each of the three types of utility buildings was exposed to approximately 0.7 psi overpressure before the planned test. In the planned test one of each of the three types was exposed to approximately 3.0 psi overpressure and one to 1.3 psi, with the intention of bracketing their overpressure survival range and obtaining data for possible economic redesign for improved blast resistance. The equipment control building utilized continuous-welded steel frames and reinforced-gypsum curtain-wall construction. The control building was exposed to approximately 4.1 psi, in the anticipated fringe zone of major structural damage, to determine its protective capabilities. The blast-resistant equipment control building was nat structurally damaged by the blast, thus exceeding the expectations of the design. Each of the three utility buildings received severe damage at the near range, one being completely destroyed, whereas at the far range the damage in every case was repairable. The test results are discussed, and recommendations for improved designs are made. Damage records during the unexpected test and at the far range in the planned test are correlated by means of dynamic analyses with pressuretime data and studies of structural resintance. Pressure-time information is appended. (auth)

Johnston, B.G.

1956-02-01T23:59:59.000Z

412

Propagation of Reactions in Thermally-damaged PBX-9501  

SciTech Connect

A thermally-initiated explosion in PBX-9501 (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) is observed in situ by flash x-ray imaging, and modeled with the LLNL multi-physics arbitrary-Lagrangian-Eulerian code ALE3D. The containment vessel deformation provides a useful estimate of the reaction pressure at the time of the explosion, which we calculate to be in the range 0.8-1.4 GPa. Closely-coupled ALE3D simulations of these experiments, utilizing the multi-phase convective burn model, provide detailed predictions of the reacted mass fraction and deflagration front acceleration. During the preinitiation heating phase of these experiments, the solid HMX portion of the PBX-9501 undergoes a {beta}-phase to {delta}-phase transition which damages the explosive and induces porosity. The multi-phase convective burn model results demonstrate that damaged particle size and pressure are critical for predicting reaction speed and violence. In the model, energetic parameters are taken from LLNL's thermochemical-kinetics code Cheetah and burn rate parameters from Son et al. (2000). Model predictions of an accelerating deflagration front are in qualitative agreement with the experimental images assuming a mode particle diameter in the range 300-400 {micro}m. There is uncertainty in the initial porosity caused by thermal damage of PBX-9501 and, thus, the effective surface area for burning. To better understand these structures, we employ x-ray computed tomography (XRCT) to examine the microstructure of PBX-9501 before and after thermal damage. Although lack of contrast between grains and binder prevents the determination of full grain size distribution in this material, there are many domains visible in thermally damaged PBX-9501 with diameters in the 300-400 {micro}m range.

Tringe, J W; Glascoe, E A; Kercher, J R; Willey, T M; Springer, H K; Greenwood, D W; Molitoris, J D; Smilowitz, L; Henson, B F; Maienschein, J L

2010-03-05T23:59:59.000Z

413

Study Shows Roles of Receptor, Thiol on Adaptive Response  

NLE Websites -- All DOE Office Websites (Extended Search)

Study Shows Roles of Receptor, Thiol on Adaptive Response Study Shows Roles of Receptor, Thiol on Adaptive Response Jeffrey Murley Jeffrey Murley, Ph.D. David Grdina, Ph.D. Low Dose program-supported scientists at The University of Chicago have gained more insight into adaptive protective responses indicating the role of oxidative stress, the role of reactive oxygen species (ROS), and the induction of SOD2 (manganese Superoxide Dismutase) activity. These changes are central to the production of adaptive protective responses. Why Study Adaptive Response? Exposing cells to low doses of ionizing radiation has been reported to elevate resistance to genomic damage when the same cells are subsequently exposed to a much higher dose of radiation. This phenomenon, called adaptive response, is characterized by an increase

414

The discrepancies in multistep damage evolution of yttria-stabilized zirconia irradiated with different ions  

SciTech Connect

This paper reports a comprehensive investigation of structural damage in yttria-stabilized zirconia irradiated with different ions over a wide fluence range. A similar multistep damage accumulation exists for the irradiations of different ions, but the critical doses for occurrence of second damage step, characterized by a faster increase in damage fraction, and the maximum elastic strain at the first damage step are varied and depend on ion mass. For irradiations of heavier ions, the second damage step occurs at a higher dose with a lower critical elastic strain. Furthermore, larger extended defects were observed in the irradiations of heavy ions at the second damage step. Associated with other experiment results and multistep damage accumulation model, the distinct discrepancies in the damage buildup under irradiations of different ions were interpreted by the effects of electronic excitation, energy of primary knock-on atom and chemistry contributions of deposited ions.

Yang, Tengfei [Peking University; Taylor, Caitlin A. [University of Tennessee, Knoxville (UTK); Kong, Shuyan [Peking University; Wang, Chenxu [Peking University; Zhang, Yanwen [ORNL; Huang, Xuejun [Peking University; Xue, Jianming [Peking University; Yan, Sha [Peking University; Wang, Yugang [Peking University

2013-01-01T23:59:59.000Z

415

Global methylation responses to low dose radiation exposure  

NLE Websites -- All DOE Office Websites (Extended Search)

methylation responses to low dose radiation exposure methylation responses to low dose radiation exposure Pamela J Sykes, Michelle R Newman, Benjamin J Blyth and Rebecca J Ormsby Haematology and Genetic Pathology, Flinders University and Medical Centre, Flinders Centre for Cancer Prevention and Control, Bedford Park, Adelaide, South Australia 5042 Australia. (pam.sykes@flinders.edu.au). Our goal is to study the mechanisms involved in biological responses to low doses of radiation in vivo in the dose range that is relevant to population and occupational exposures. At high radiation doses, DNA double-strand breaks are considered the critical lesion underlying the initiation of radiation-induced carcinogenesis. However, at the very low radiation doses relevant for the general public, the induction of DNA double-strand breaks

416

A Nucleotide-Analogue-Induced Gain of Function Corrects the Error-Prone Nature of Human DNA Polymerase iota  

Science Conference Proceedings (OSTI)

Y-family DNA polymerases participate in replication stress and DNA damage tolerance mechanisms. The properties that allow these enzymes to copy past bulky adducts or distorted template DNA can result in a greater propensity for them to make mistakes. Of the four human Y-family members, human DNA polymerase iota (hpol{iota}) is the most error-prone. In the current study, we elucidate the molecular basis for improving the fidelity of hpol{iota} through use of the fixed-conformation nucleotide North-methanocarba-2{prime}-deoxyadenosine triphosphate (N-MC-dATP). Three crystal structures were solved of hpol{iota} in complex with DNA containing a template 2{prime}-deoxythymidine (dT) paired with an incoming dNTP or modified nucleotide triphosphate. The ternary complex of hpol{iota} inserting N-MC-dATP opposite dT reveals that the adenine ring is stabilized in the anti orientation about the pseudo-glycosyl torsion angle, which mimics precisely the mutagenic arrangement of dGTP:dT normally preferred by hpol{iota}. The stabilized anti conformation occurs without notable contacts from the protein but likely results from constraints imposed by the bicyclo[3.1.0]hexane scaffold of the modified nucleotide. Unmodified dATP and South-MC-dATP each adopt syn glycosyl orientations to form Hoogsteen base pairs with dT. The Hoogsteen orientation exhibits weaker base-stacking interactions and is less catalytically favorable than anti N-MC-dATP. Thus, N-MC-dATP corrects the error-prone nature of hpol{iota} by preventing the Hoogsteen base-pairing mode normally observed for hpol{iota}-catalyzed insertion of dATP opposite dT. These results provide a previously unrecognized means of altering the efficiency and the fidelity of a human translesion DNA polymerase.

Ketkar, Amit; Zafar, Maroof K.; Banerjee, Surajit; Marquez, Victor E.; Egli, Martin; Eoff, Robert L. (Cornell); (Vanderbilt); (NCI); (Arkansas)

2012-10-25T23:59:59.000Z

417

ENERGY EMERGENCY RESPONSE PLAN  

E-Print Network (OSTI)

CALIFORNIA ENERGY COMMISSION ENERGY EMERGENCY RESPONSE PLAN COMMISSIONREPORT October 2006 CEC-600 Deputy Director FUELS AND TRANSPORTATION DIVISION #12;The Energy Emergency Response Plan is prepared, safety, and welfare. #12;ACKNOWLEDGEMENTS The Energy Emergency Response Plan was prepared from

418

A Coupled Micromechanical Model of Moisture-Induced Damage in Asphalt Mixtures: Formulation and Applications  

E-Print Network (OSTI)

The deleterious effect of moisture on the structural integrity of asphalt mixtures has been recognized as one of the main causes of early deterioration of asphalt pavements. This phenomenon, usually referred to as moisture damage, is defined as the progressive loss of structural integrity of the mixture that is primarily caused by the presence of moisture in liquid or vapor state. Moisture damage is associated with the development of different physical, mechanical, and chemical processes occurring within the microstructure of the mixture at different intensities and rates. Although there have been important advancements in identifying and characterizing this phenomenon, there is still a lack of understanding of the damage mechanisms occurring at the microscopic level. This situation has motivated the research work reported in this dissertation. The main objective of this dissertation is to formulate and apply a numerical micromechanical model of moisture-induced damage in asphalt mixtures. The model focuses on coupling the effects of moisture diffusionone of the three main modes of moisture transport within asphalt mixtureswith the mechanical performance of the microstructure. Specifically, the model aims to account for the effect of moisture diffusion on the degradation of the viscoelastic bulk matrix of the mixture (i.e., cohesive degradation) and on the gradual deterioration of the adhesive bonds between the aggregates and the asphalt matrix (i.e., adhesive degradation). The micromechanical model was applied to study the role of some physical and mechanical properties of the constitutive phases of the mixtures on the susceptibility of the mixture to moisture damage. The results from this analysis suggest that the diffusion coefficients of the asphalt matrix and aggregates, as well as the bond strength of the aggregate-matrix interface, have the most influence on the moisture susceptibility of the mixtures. The micromechanical model was further used to investigate the influence of the void phase of asphalt mixtures on the generation of moisture-related deterioration processes. Two different probabilistic-based approaches were used to accomplish this objective. In the first approach, a volumetric distribution of air voids sizes measured using X-Ray Computed Tomography in a dense-graded asphalt mixture was used to generate probable void structures in a microstructure of an asphalt mixture. In the second approach, a stochastic modeling technique based on random field theory was used to generate probable air voids distributions of the mixture. In this second approach, the influence of the air voids was accounted for by making the physical and mechanical properties of the asphalt matrix dependent on probable voids distributions. Although both approaches take into consideration the characteristics of the air void phase on the mechanical response of the mixtures subjected to moist environments, the former explicitly introduces the air phase within the microstructure while the latter indirectly includes its effects by modifying the material properties of the bulk matrix. The results from these simulations demonstrated that the amount, variability and location of air voids are decisive in determining the moisture-dependent performance of asphalt mixtures. The results from this dissertation provide new information on the kinetics of moisture damage mechanisms in asphalt mixtures. In particular, the results obtained from applying the micromechanical model permitted identification of the relative influence of the characteristics of the constitutive phases of a mixture on its moisture-related mechanical performance. This information can be used as part of design methodologies of asphalt mixtures, and/or as an input in life-cycle analysis models and maintenance programs of road infrastructure.

Caro Spinel, Silvia

2009-12-01T23:59:59.000Z

419

Low Dose Radiation Research Program: An Expression Array Strategy...  

NLE Websites -- All DOE Office Websites (Extended Search)

Mouse Strain Specific DNA Damage Response Pathways in Mammary Tissue Allan Balmain Cancer Research Institute, University of California at San Francisco, San Francisco CA...

420

Low Dose Radiation Research Program: Slide Shows  

NLE Websites -- All DOE Office Websites (Extended Search)

Dose Health Effects of Radiation Health Effects of Radiation Adaptive Response to Low Dose Radiation PDF Background Radiation PDF Bystander Effects PDF Dirty Bombs PDF DNA Damage...

Note: This page contains sample records for the topic "dna damage response" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Low Dose Radiation Research Program: Ionizing Radiation-induced...  

NLE Websites -- All DOE Office Websites (Extended Search)

p53-directed, DNA damage response pathway. The p53 protein, activated indirectly by the ATM protein kinase, transactivates target genes and thus induces cell cycle progression...

422

NFkB-mediated Prosurvival Network in Low Dose Radiation-induced...  

NLE Websites -- All DOE Office Websites (Extended Search)

approaches to improve normal tissue protection in caner radiation therapy. We found that ATM, a DNA damage sensor, is induced by LDR and responsible for activation of transcription...

423

Biology Department - Brookhaven National Laboratory  

NLE Websites -- All DOE Office Websites (Extended Search)

Biology Scientific Staff Mammalian Systems Krassimira Botcheva DNA damage responses; whole genome p53 & chromatin analysis Paul Freimuth Adenovirus attachment, Expression & folding...

424

Dual wavelength laser damage testing for high energy lasers.  

Science Conference Proceedings (OSTI)

As high energy laser systems evolve towards higher energies, fundamental material properties such as the laser-induced damage threshold (LIDT) of the optics limit the overall system performance. The Z-Backlighter Laser Facility at Sandia National Laboratories uses a pair of such kiljoule-class Nd:Phosphate Glass lasers for x-ray radiography of high energy density physics events on the Z-Accelerator. These two systems, the Z-Beamlet system operating at 527nm/ 1ns and the Z-Petawatt system operating at 1054nm/ 0.5ps, can be combined for some experimental applications. In these scenarios, dichroic beam combining optics and subsequent dual wavelength high reflectors will see a high fluence from combined simultaneous laser exposure and may even see lingering effects when used for pump-probe configurations. Only recently have researchers begun to explore such concerns, looking at individual and simultaneous exposures of optics to 1064 and third harmonic 355nm light from Nd:YAG [1]. However, to our knowledge, measurements of simultaneous and delayed dual wavelength damage thresholds on such optics have not been performed for exposure to 1054nm and its second harmonic light, especially when the pulses are of disparate pulse duration. The Z-Backlighter Facility has an instrumented damage tester setup to examine the issues of laser-induced damage thresholds in a variety of such situations [2] . Using this damage tester, we have measured the LIDT of dual wavelength high reflectors at 1054nm/0.5ps and 532nm/7ns, separately and spatially combined, both co-temporal and delayed, with single and multiple exposures. We found that the LIDT of the sample at 1054nm/0.5ps can be significantly lowered, from 1.32J/cm{sup 2} damage fluence with 1054/0.5ps only to 1.05 J/cm{sup 2} with the simultaneous presence of 532nm/7ns laser light at a fluence of 8.1 J/cm{sup 2}. This reduction of LIDT of the sample at 1054nm/0.5ps continues as the fluence of 532nm/7ns laser light simultaneously present increases. The reduction of LIDT does not occur when the 2 pulses are temporally separated. This paper will also present dual wavelength LIDT results of commercial dichroic beam-combining optics simultaneously exposed with laser light at 1054nm/2.5ns and 532nm/7ns.

Atherton, Briggs W.; Rambo, Patrick K.; Schwarz, Jens; Kimmel, Mark W.

2010-05-01T23:59:59.000Z

425

Response of Desulfovibrio vulgaris to Alkaline Stress  

SciTech Connect

The response of exponentially growing Desulfovibrio vulgarisHildenborough to pH 10 stress was studied using oligonucleotidemicroarrays and a study set of mutants with genes suggested by microarraydata to be involved in the alkaline stress response deleted. The datashowed that the response of D. vulgaris to increased pH is generallysimilar to that of Escherichia coli but is apparently controlled byunique regulatory circuits since the alternative sigma factors (sigma Sand sigma E) contributing to this stress response in E. coli appear to beabsent in D. vulgaris. Genes previously reported to be up-regulated in E.coli were up-regulated in D. vulgaris; these genes included three ATPasegenes and a tryptophan synthase gene. Transcription of chaperone andprotease genes (encoding ATP-dependent Clp and La proteases and DnaK) wasalso elevated in D. vulgaris. As in E. coli, genes involved in flagellumsynthesis were down-regulated. The transcriptional data also identifiedregulators, distinct from sigma S and sigma E, that are likely part of aD. vulgaris Hildenborough-specific stress response system.Characterization of a study set of mutants with genes implicated inalkaline stress response deleted confirmed that there was protectiveinvolvement of the sodium/proton antiporter NhaC-2, tryptophanase A, andtwo putative regulators/histidine kinases (DVU0331 andDVU2580).

Stolyar, S.; He, Q.; He, Z.; Yang, Z.; Borglin, S.E.; Joyner, D.; Huang, K.; Alm, E.; Hazen, T.C.; Zhou, J.; Wall, J.D.; Arkin, A.P.; Stahl, D.A.

2007-11-30T23:59:59.000Z

426

An energy-conserving two-temperature model of radiation damage in single-component and binary Lennard-Jones crystals  

SciTech Connect

Two-temperature models are used to represent the interaction between atoms and free electrons during thermal transients such as radiation damage, laser heating, and cascade simulations. In this paper, we introduce an energy-conserving version of an inhomogeneous finite reservoir two-temperature model using a Langevin thermostat to communicate energy between the electronic and atomic subsystems. This energy-conserving modification allows the inhomogeneous two-temperature model to be used for longer and larger simulations and simulations of small energy phenomena, without introducing nonphysical energy fluctuations that may affect simulation results. We test this model on the annealing of Frenkel defects. We find that Frenkel defect annealing is largely indifferent to the electronic subsystem, unless the electronic subsystem is very tightly coupled to the atomic subsystem. We also consider radiation damage due to local deposition of heat in two idealized systems. We first consider radiation damage in a large face-centered-cubic Lennard-Jones (LJ) single-component crystal that readily recrystallizes. Second, we consider radiation damage in a large binary glass-forming LJ crystal that retains permanent damage. We find that the electronic subsystem parameters can influence the way heat is transported through the system and have a significant impact on the number of defects after the heat deposition event. We also find that the two idealized systems have different responses to the electronic subsystem. The single-component LJ system anneals most rapidly with an intermediate electron-ion coupling and a high electronic thermal conductivity. If sufficiently damaged, the binary glass-forming LJ system retains the least permanent damage with both a high electron-ion coupling and a high electronic thermal conductivity. In general, we find that the presence of an electronic gas can affect short and long term material annealing.

Phillips, Carolyn L. [Applied Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States); Crozier, Paul S. [Department of Multiscale Dynamic Materials Modeling, Sandia National Laboratories, P.O. Box 5800, MS 1322, Albuquerque, New Mexico 87185-1322 (United States)

2009-08-21T23:59:59.000Z

427

Complexation of DNA with Cationic Surfactant  

E-Print Network (OSTI)

Transfection of an anionic polynucleotide through a negatively charged membrane is an important problem in genetic engineering. The direct association of cationic surfactant to DNA decreases the effective negative charge of the nucleic acid, allowing the DNA-surfactant complex to approach a negatively charged membrane. The paper develops a theory for solutions composed of polyelectrolyte, salt, and ionic surfactant. The theoretical predictions are compared with the experimental measurements. PACS.05.70.Ce- Thermodynamic functions and equations of state PACS.61.20.Qg- Structure of associated liquids: electrolytes, molten salts, etc. PACS.61.25.Hq- Macromolecular and polymer solutions; polymer melts; swelling Corresponding author;

Paulo S. Kuhn; Marcia C. Barbosa; Yan Levin

1999-01-01T23:59:59.000Z

428

Demand Response Spinning Reserve  

NLE Websites -- All DOE Office Websites (Extended Search)

Demand Response Spinning Reserve Title Demand Response Spinning Reserve Publication Type Report Year of Publication 2007 Authors Eto, Joseph H., Janine Nelson-Hoffman, Carlos...

429

DOE Functions and Responsibilities  

NLE Websites -- All DOE Office Websites (Extended Search)

Safety and Security is responsible for developing and maintaining the Department's Directives that address safety management functions, responsibilities and authorities (FRA)....

430

Mass spectrometric studies of laser damage in calcium fluoride  

Science Conference Proceedings (OSTI)

Both electron impact- and laser-ionization-mass spectrometry have been used to prove the material spalled from CaF/sub 2/ surfaces by the fundamental (1.06..mu..) and harmonic (355 nm and 266 nm) outputs from a Q-switched Nd:YAG laser. We have identified a number of gas phase products, including Ca, CaF and tentatively, CaF/sub 2/, and have measured their translational and internal energy distributions. Results suggest that while the 1.06..mu.. experiments can be adequately modeled in terms of a single damage mechanism (likely avalanche breakdown), the short-wavelength results suggest the onset of second mechanism, perhaps multiphoton absorption. This is consistent with both the observed bimodal velocity distribution following short-wavelength damage, and with the decrease in CaF vibrational and rotational excitation.

Nogar, N.S.; Apel, E.C.; Estler, R.C.

1986-01-01T23:59:59.000Z

431

Neutron damage reduction in a traveling wave reactor  

Science Conference Proceedings (OSTI)

Traveling wave reactors are envisioned to run on depleted or natural uranium with no need for enrichment or reprocessing, and in a manner which requires little to no operator intervention. If feasible, this type of reactor has significant advantages over conventional nuclear power systems. However, a practical implementation of this concept is challenging as neutron irradiation levels many times greater than those in conventional reactors appear to be required for a fission wave to propagate. Radiation damage to the fuel and cladding materials presents a significant obstacle to a practical design. One possibility for reducing damage is to soften the neutron energy spectrum. Here we show that using a uranium oxide fuel form will allow a shift in the neutron spectrum that can result in at least a three fold decrease in dpa levels for fuel cladding and structural steels within the reactor compared with the dpa levels expected when using a uranium metal fuel. (authors)

Osborne, A. G.; Deinert, M. R. [Dept. of Mechanical Engineering, Univ. of Texas at Austin, Austin, TX (United States)

2012-07-01T23:59:59.000Z

432

Natural completions - overcoming the damage caused by drilling and perforations  

SciTech Connect

Natural completions are suggested as a way to avoid or overcome damage to the formation caused by drilling and perforating. Formation damage may take the form of plugged passageways which remain closed because formation pressure does not exceed that of the plug material. Natural completions refer to using maximum differential pressure toward the wellbore, so that such obstructions in passageways can less easily exist. The method allows the formation pressure to backsurge perforation tunnels immediately following detonation of the guns, with the objectives of obtaining deep, clean perforations with the crushed zone and debris completely removed from the perforations. Procedures for natural completions are described and illustrated. A case history is given where the natural completion method restores productivity of a well.

Perry, G.; Smith, G.

1980-04-01T23:59:59.000Z

433

Database of average-power damage thresholds at 1064 nm  

Science Conference Proceedings (OSTI)

We have completed a database of average-power, laser-induced, damage thresholds at 1064 nm on a variety of materials. Measurements were made with a newly constructed laser to provide design input for moderate and high average-power laser projects. The measurements were conducted with 16-ns pulses at pulse-repetition frequencies ranging from 6 to 120 Hz. Samples were typically irradiated for time ranging from a fraction of a second up to 5 minutes (36,000 shots). We tested seven categories of samples which included antireflective coatings, high reflectors, polarizers, single and multiple layers of the same material, bare and overcoated metal surfaces, bare polished surfaces, and bulk materials. The measured damage threshold ranged from 46 J/cm/sup 2/ for a bare polished glass substrate. 4 refs., 7 figs., 1 tab.

Rainer, F.; Hildum, E.A.; Milam, D.

1987-12-14T23:59:59.000Z

434

Influence of radiation damage on ruby as a pressure gauge  

SciTech Connect

This study tackles the question if ruby crystals, irradiated with energetic heavy ions, can still be used as reliable pressure sensors. The problem is linked to novel irradiation experiments, exposing pressurized samples to swift heavy-ion beams. In order to test and quantify a possible influence of radiation damage on the laser-induced fluorescence lines of ruby (Al{sub 2}O{sub 3}:Cr{sup 3+}), small crystals were exposed to different heavy ions (Xe, Au, and U) with kinetic energies of several giga-electron volt at ambient as well as high-pressure conditions. With increasing fluence (ions/cm{sup 2}), the R{sub 1} and R{sub 2} lines shift both to lower wavelengths which leads to an underestimation of the pressure. An empirical correction term {epsilon} is proposed to include the irradiation damage effect into the commonly employed ruby calibration scale.

Schuster, B. [Institut fuer Festkoerperphysik, Technische Universitaet Darmstadt, Hochschulstrasse 6, 64289 Darmstadt (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany); Weikusat, C.; Miletich, R. [Universitaet Heidelberg, Im Neuenheimer Feld 234-236, 69120 Heidelberg (Germany); Trautmann, C.; Neumann, R. [GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany); Fujara, F. [Institut fuer Festkoerperphysik, Technische Universitaet Darmstadt, Hochschulstrasse 6, 64289 Darmstadt (Germany)

2010-11-01T23:59:59.000Z

435

Collaborative Post-Disaster Damage Mapping via Geo Web Services  

E-Print Network (OSTI)

Action focus on post disaster re- sponse, frequently linking disaster response and management efforts disaster response. ImageCat Inc., for example, has been developing tools for more efficient image based disaster response, most re- cently the Virtual Disaster Viewer (VDV) based on MS Virtual Earth, which

Köbben, Barend

436

Summary of radiation damage studies on rare earth permanent magnets  

SciTech Connect

With the proposed use of permanent magnets for both the NLC and the VLHC the issue flux loss due to radiation damage needs to be fully understood. There exist many papers on the subject. There are many difficulties in drawing conclusions from all of these data. First there is the difference methods of dosimetry, second different types of magnets and magnetic arrangements, and third different manufacturers of magnet material. This paper provides a summary of the existing literature on the subject.

J. T. Volk

2002-11-19T23:59:59.000Z

437

A micromechanics based ductile damage model for anisotropic titanium alloys  

E-Print Network (OSTI)

The hot-workability of Titanium (Ti) alloys is of current interest to the aerospace industry due to its widespread application in the design of strong and light-weight aircraft structural components and engine parts. Motivated by the need for accurate simulation of large scale plastic deformation in metals that exhibit macroscopic plastic anisotropy, such as Ti, a constitutive model is developed for anisotropic materials undergoing plastic deformation coupled with ductile damage in the form of internal cavitation. The model is developed from a rigorous micromechanical basis, following well-known previous works in the field. The model incorporates the porosity and void aspect ratio as internal damage variables, and seeks to provide a more accurate prediction of damage growth compared to previous existing models. A closed form expression for the macroscopic yield locus is derived using a Hill-Mandel homogenization and limit analysis of a porous representative volume element. Analytical expressions are also developed for the evolution of the internal variables, porosity and void shape. The developed yield criterion is validated by comparison to numerically determined yield loci for specific anisotropic materials, using a numerical limit analysis technique developed herein. The evolution laws for the internal variables are validated by comparison with direct finite element simulations of porous unit cells. Comparison with previously published results in the literature indicates that the new model yields better agreement with the numerically determined yield loci for a wide range of loading paths. Use of the new model in continuum finite element simulations of ductile fracture may be expected to lead to improved predictions for damage evolution and fracture modes in plastically anisotropic materials.

Keralavarma, Shyam Mohan

2008-05-01T23:59:59.000Z

438

EPRI-SQUG Damage-Indicating Parameter Information  

Science Conference Proceedings (OSTI)

This report provides information assembled for the purpose of developing damage-indicating parameters (DIPs) for power plant equipment. An existing Electric Power Research Institute (EPRI) seismic experience database is used to develop candidate DIP values associated with two database sites subjected to earthquake events. The two sites are described, the candidate DIPs are derived from the recorded site motions, and the equipment items at these sites are categorized according to performance during an ear...

2011-09-13T23:59:59.000Z

439

Damage tolerance design procedures for an automotive composite  

DOE Green Energy (OSTI)

Among the durability issues of concern in the use of composites in automobile structures is the damaging effects that low-energy impacts (e.g., tool drops and roadway kickups) might have on strength and stiffness. This issue was experimentally investigated, and recommended design evaluation procedures were developed for a candidate automotive structural composite--a structural reaction injection-molded polyurethane reinforced with continuous strand, swirl-mat E-glass fibers. Two test facilities were built to cover the range of impacts of interest--a pendulum device to characterize the effects of relative heavy objects at low velocities and an air gun to characterize the effects of relatively light objects at higher velocities. In all cases, the test specimen was a 9 x 9 x 1/8-in.-thick plate clamped on an 8-in.-diam circle. Sixty-five impact tests were performed. Included were tests using various impactor sizes and weights, tests at {minus}40 F, and tests on specimens that has been presoaked in water or exposed to battery acid. Damage areas were determined using ultrasonic C-scans, and the resulting areas were found to correlate with the quantity impactor mass to a power times velocity. A design curve was derived from the correlation and validated using dropped brick tests. To evaluate strength and stiffness reductions, the impacted plate specimens were cut into tensile, compressive, and fatigue test specimens that were used to determine reductions as a function of damage area. It was found that for design purposes, the strength reduction could be determined by representing the damage area by a circular hole of equivalent area.

Corum, J.M.; Battiste, R.L.

1998-11-01T23:59:59.000Z

440

Analysis of Two Widespread Versions of a Bacterial Replicative DNA Polymerase  

E-Print Network (OSTI)

DnaE1-pol subunits and the helicase (DnaB). SSB stands forto each polymerase, a (2) helicase for unwinding DNA into

Guenther, Joel Michael

2010-01-01T23:59:59.000Z