National Library of Energy BETA

Sample records for kyu taek cho

  1. CHO Invest EU1 | Open Energy Information

    Open Energy Info (EERE)

    CHO Invest EU1 Jump to: navigation, search Name: CHO Invest EU1 Place: Morcenx, France Product: France-based CHO Power electricity production unit Coordinates: 44.033454,...

  2. Yanglai\tCho,\tat\tright,\tmanning\tthe\tceremonial\t"shovel"

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    on June 14, 2015, of complications from pneumonia. He was 82 years of age. Yanglai Cho "Yang Cho was the primary force behind Argonne's effort in the 1980s to build the Advanced...

  3. Cho decomposition of electrically charged one-half monopole

    SciTech Connect (OSTI)

    Ng, Ban-Loong; Teh, Rosy; Wong, Khai-Ming

    2014-03-05

    Recently we have carried out some work on the Cho decomposition of the electrically neutral, finite energy one-half monopole solution of the SU(2) Yang-Mills-Higgs field theory. In this paper, we performed the decomposition of the electrically charged solution using the same numerical procedure. The gauge potential of the one-half dyon solution is decomposed into Abelian and non-Abelian components. The semi-infinite string singularity in the gauge potential is a contribution of the Higgs field and hence topological in nature. The string singularity cannot be cancelled by the non-Abelian components of the gauge potential. However, the string singularity is integrable and the energy of the solution is finite. By decomposing the magnetic fields and covariant derivatives of the Higgs field into three isospin space directions, we are able to provide conclusive evidence that the constructed one-half dyon is certainly a non-BPS solution even in the limit of vanishing Higgs self-coupling constant and electric charge. Furthermore, we found that the time component of gauge function is parallel to the Higgs field in isospace only at large distances, elsewhere they are non-parallel.

  4. Barrierless proton transfer across weak CH?O hydrogen bonds in dimethyl ether dimer

    SciTech Connect (OSTI)

    Yoder, Bruce L. West, Adam H. C.; Signorell, Ruth; Bravaya, Ksenia B.; Bodi, Andras; Sztáray, Bálint

    2015-03-21

    We present a combined computational and threshold photoelectron photoion coincidence study of two isotopologues of dimethyl ether, (DME ? h{sub 6}){sub n} and (DME ? d{sub 6}){sub n}n = 1 and 2, in the 9–14 eV photon energy range. Multiple isomers of neutral dimethyl ether dimer were considered, all of which may be present, and exhibited varying C–H?O interactions. Results from electronic structure calculations predict that all of them undergo barrierless proton transfer upon photoionization to the ground electronic state of the cation. In fact, all neutral isomers were found to relax to the same radical cation structure. The lowest energy dissociative photoionization channel of the dimer leads to CH{sub 3}OHCH{sub 3}{sup +} by the loss of CH{sub 2}OCH{sub 3} with a 0 K appearance energy of 9.71 ± 0.03 eV and 9.73 ± 0.03 eV for (DME ? h{sub 6}){sub 2} and deuterated (DME ? d{sub 6}){sub 2}, respectively. The ground state threshold photoelectron spectrum band of the dimethyl ether dimer is broad and exhibits no vibrational structure. Dimerization results in a 350 meV decrease of the valence band appearance energy, a 140 meV decrease of the band maximum, thus an almost twofold increase in the ground state band width, compared with DME ? d{sub 6} monomer.

  5. PREPARED FOR THE U.S. DEPARTMENT OF ENERGY, UNDER CONTRACT DE-AC02-76-CHO-3073

    Office of Scientific and Technical Information (OSTI)

    PREPARED FOR THE U.S. DEPARTMENT OF ENERGY, UNDER CONTRACT DE-AC02-76-CHO-3073 PPPL-2818 PPPL-2818 UC-422,427 THREE-DIMENSIONAL TOKAMAKEQUILIBRIA * INTHE PRESENCEOF RESONANTFIELDERRORS BY A. REIMANAND D. MONTICELLO January 1992 IDIRII_I['TO_I I_L.ABMA I_lYSmcl L.ABORATC)RY i NOTICE v, This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Govern,nent nor any agency thereof, nor any of their employees, makes any warranty,

  6. PREPARED FOR THE U.S. DEPARTMENT OF ENERGY, UNDER CONTRACT DE-AC02-76-CHO-3073

    Office of Scientific and Technical Information (OSTI)

    UNDER CONTRACT DE-AC02-76-CHO-3073 PPPL-3099 PPPL-3099 UC-427 & SINGULAR SURFACES IN THE OPEN FIELD LINE REGION OF A DIVERTED TOKAMAK BY A. REIMAN MAY 1995 PRINCETON PLASMA PHYSICS LABORATORY - - NOTICE J This report was prepared unt of work sponsored by an agency of the United States Government. Nei States Government nor any agency thereof, nor any of their mploye y, express or implied, or assumes any legal liability or responsibi , completeness, or usefulness of any information,

  7. PREPARED FOR THE U.S. DEPARTMENT OF ENERGY, UNDER CONTRACT DE-AC02-76-CHO-3073

    Office of Scientific and Technical Information (OSTI)

    r/0*O> PREPARED FOR THE U.S. DEPARTMENT OF ENERGY, UNDER CONTRACT DE-AC02-76-CHO-3073 PPPL-2760 UC-421,427 PPPL-2760 TOKAMAK ERROR FIELDS AND LOCKED MODES BY A. REIMAN AND D. MONTICELLO May 1991 P B I N C I T O N | P L A S M A P H Y S I C S I L A I O R A T Q R V I 1 sr-JiL-tK'- PRINCETON UNIVERSITY, PRINCETON, NEW JERSEY * U I 1 \^{~ r l * l A - ' i - U M L N l JS (JIVLilViif^O NOTICE This report was prepared as an account of work sponsored by an agency of the United States Government.

  8. Photolysis of CH{sub 3}CHO at 248 nm: Evidence of triple fragmentation from primary quantum yield of CH{sub 3} and HCO radicals and H atoms

    SciTech Connect (OSTI)

    Morajkar, Pranay; Schoemaecker, Coralie; Fittschen, Christa; Bossolasco, Adriana

    2014-06-07

    Radical quantum yields have been measured following the 248 nm photolysis of acetaldehyde, CH{sub 3}CHO. HCO radical and H atom yields have been quantified by time resolved continuous wave Cavity Ring Down Spectroscopy in the near infrared following their conversion to HO{sub 2} radicals by reaction with O{sub 2}. The CH{sub 3} radical yield has been determined using the same technique following their conversion into CH{sub 3}O{sub 2}. Absolute yields have been deduced for HCO radicals and H atoms through fitting of time resolved HO{sub 2} profiles, obtained under various O{sub 2} concentrations, to a complex model, while the CH{sub 3} yield has been determined relative to the CH{sub 3} yield from 248 nm photolysis of CH{sub 3}I. Time resolved HO{sub 2} profiles under very low O{sub 2} concentrations suggest that another unknown HO{sub 2} forming reaction path exists in this reaction system besides the conversion of HCO radicals and H atoms by reaction with O{sub 2}. HO{sub 2} profiles can be well reproduced under a large range of experimental conditions with the following quantum yields: CH{sub 3}CHO?+?h?{sub 248nm} ? CH{sub 3}CHO{sup *}, CH{sub 3}CHO{sup *} ? CH{sub 3}?+?HCO??{sub 1a} = 0.125?±?0.03, CH{sub 3}CHO{sup *} ? CH{sub 3}?+?H?+?CO??{sub 1e} = 0.205?±?0.04, CH{sub 3}CHO{sup *}?{sup o{sub 2}}CH{sub 3}CO?+?HO{sub 2}??{sub 1f} = 0.07?±?0.01. The CH{sub 3}O{sub 2} quantum yield has been determined in separate experiments as ?{sub CH{sub 3}} = 0.33 ± 0.03 and is in excellent agreement with the CH{sub 3} yields derived from the HO{sub 2} measurements considering that the triple fragmentation (R1e) is an important reaction path in the 248 nm photolysis of CH{sub 3}CHO. From arithmetic considerations taking into account the HO{sub 2} and CH{sub 3} measurements we deduce a remaining quantum yield for the molecular pathway: CH{sub 3}CHO{sup *} ? CH{sub 4}?+?CO??{sub 1b} = 0.6. All experiments can be consistently explained with absence of the formerly considered pathway: CH{sub 3}CHO{sup *} ? CH{sub 3}CO?+?H??{sub 1c} = 0.

  9. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Mustafayev, Azar (11) Huang, Peisi (10) Bae, Kyu Jung (8) Mickelson, Dan (7) Balazs, Csaba ... radiatively-driven naturalness Bae, Kyu Jung ; Baer, Howard ; Nagata, Natsumi ; Serce, ...

  10. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Keasling, Jay (3) Lee, Taek Soon (3) Rajeev, Lara (3) Redding, Alyssa M. (3) Tang, Yinjie ... Mapping the Two-component Regulatory Networks in Desulfovibrio vulgaris Rajeev, Lara ; ...

  11. Numerical Verification of Bounce Harmonic Resonances in Neoclassical...

    Office of Scientific and Technical Information (OSTI)

    Authors: Kimin Kim, Jong-Kyu Park and Allen H. Boozer Publication Date: 2013-04-17 OSTI Identifier: 1074353 Report Number(s):...

  12. Prospects for Higgs coupling measurements in SUSY with radiatively...

    Office of Scientific and Technical Information (OSTI)

    Title: Prospects for Higgs coupling measurements in SUSY with radiatively-driven naturalness Authors: Bae, Kyu Jung ; Baer, Howard ; Nagata, Natsumi ; Serce, Hasan Publication ...

  13. Numerical Verification of Bounce Harmonic Resonances in Neoclassical

    Office of Scientific and Technical Information (OSTI)

    for Tokamaks Kimin Kim, Jong-Kyu Park and Allen H. Boozer 70 PLASMA PHYSICS AND FUSION TECHNOLOGY Tokamaks, Numerical Verification Tokamaks, Numerical Verification This...

  14. TITLE AUTHORS SUBJECT SUBJECT RELATED DESCRIPTION PUBLISHER AVAILABILI...

    Office of Scientific and Technical Information (OSTI)

    Viscosity for Tokamaks Kimin Kim Jong Kyu Park and Allen H Boozer PLASMA PHYSICS AND FUSION TECHNOLOGY Tokamaks Numerical Verification Tokamaks Numerical Verification This Letter...

  15. A Long-Life, High-Rate Lithium/Sulfur Cell: A Multifaceted Approach...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Long-Life, High-Rate LithiumSulfur Cell: A Multifaceted Approach to Enhancing Cell Performance Min-Kyu Song, , Yuegang Zhang,* ,, and Elton J. Cairns* ,, The...

  16. Structure of the oxygen-annealed chalcogenide superconductor...

    Office of Scientific and Technical Information (OSTI)

    x Authors: Hu, Hefei ; Zuo, Jian-Min ; Zheng, Mao ; Eckstein, James N. ; Park, Wan Kyu ; Greene, Laura H. ; Wen, Jinsheng ; Xu, Zhijun ; Lin, Zhiwei ; Li, Qiang ; Gu,...

  17. Search for: All records | DOE PAGES

    Office of Scientific and Technical Information (OSTI)

    Dahl, Robert H. (1) Foo, Jee Loon (1) George, Kevin (1) Jensen, Heather M. (1) Keasling, Jay D. (1) Lee, Taek Soon (1) Leong, Susanna (1) Mukhopadhyay, Aindrila (1) Save Results...

  18. Isoprenoid based alternative diesel fuel (Patent) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    also disclosed. STR00001 Authors: Lee, Taek Soon ; Peralta-Yahya, Pamela ; Keasling, Jay D. Publication Date: 2015-08-18 OSTI Identifier: 1210882 Report Number(s): 9,109,175...

  19. Fail Safe Design for Large Capacity Lithium-ion Batteries

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Fail Safe Design for Large Capacity Lithium-ion Batteries NREL Commercialization & Tech Transfer Webinar March 27, 2011 Gi-Heon Kim gi-heon.kim@nrel.gov John Ireland, Kyu-Jin Lee,...

  20. Structure of the oxygen-annealed chalcogenide superconductor...

    Office of Scientific and Technical Information (OSTI)

    Fe1.08Te0.55Se0.45Ox Authors: Hu, Hefei ; Zuo, Jian-Min ; Zheng, Mao ; Eckstein, James N. ; Park, Wan Kyu ; Greene, Laura H. ; Wen, Jinsheng ; Xu, Zhijun ; Lin, Zhiwei ; Li,...

  1. Natural little hierarchy for SUSY from radiative breaking of...

    Office of Scientific and Technical Information (OSTI)

    Title: Natural little hierarchy for SUSY from radiative breaking of the Peccei-Quinn symmetry Authors: Bae, Kyu Jung ; Baer, Howard ; Serce, Hasan Publication Date: 2015-01-06 OSTI ...

  2. Mixed axion/gravitino dark matter from SUSY models with heavy...

    Office of Scientific and Technical Information (OSTI)

    Title: Mixed axiongravitino dark matter from SUSY models with heavy axinos Authors: Bae, Kyu Jung ; Baer, Howard ; Chun, Eung Jin ; Shin, Chang Sub Publication Date: 2015-04-14 ...

  3. Initial chemical steps in the low-temperature oxidation of

    Office of Scientific and Technical Information (OSTI)

    25-dimethylhexane. (Journal Article) | SciTech Connect Journal Article: Initial chemical steps in the low-temperature oxidation of 25-dimethylhexane. Citation Details In-Document Search Title: Initial chemical steps in the low-temperature oxidation of 25-dimethylhexane. Abstract not provided. Authors: Taatjes, Craig A. ; Rotavera, Brandon ; Osborn, David L. ; Welz, Oliver ; Sheps, Leonid ; Scheer, Adam Michael ; Savee, John David ; Simmons, Blake Alexander ; Lee, Taek-Soon ; Violi, Angela ;

  4. Component-Centered Approach Towards Oxidation Studies of Complex Biofuels.

    Office of Scientific and Technical Information (OSTI)

    (Conference) | SciTech Connect Conference: Component-Centered Approach Towards Oxidation Studies of Complex Biofuels. Citation Details In-Document Search Title: Component-Centered Approach Towards Oxidation Studies of Complex Biofuels. Abstract not provided. Authors: Rotavera, Brandon ; Welz, Oliver ; Sheps, Leonid ; Scheer, Adam Michael ; Savee, John David ; Osborn, David L. ; Simmons, Blake ; Taatjes, Craig A. ; Ali, Mohamad A. ; Lee, Taek Soon ; Violi, Angela Publication Date: 2013-07-01

  5. Search for: All records | DOE PAGES

    Office of Scientific and Technical Information (OSTI)

    Lee, Taek Soon" Name Name ORCID Search Authors Type: All Accepted Manuscript Published Article Publisher's Accepted Manuscript Journal Name: Subject: Identifier Numbers: Research Org: Sponsoring Org: Publication Date: to Update Date: to Sort: Relevance (highest to lowest) Publication Date (newest first) Publication Date (oldest first) Close Clear All Find Switch to Detail View for this search DOE PAGES Search Results Page 1 of 1 Search for: All records Creators/Authors contains: "Lee,

  6. Substantial improvements in methyl ketone production in E. coli and

    Office of Scientific and Technical Information (OSTI)

    insights on the pathway from in vitro studies (Journal Article) | SciTech Connect Journal Article: Substantial improvements in methyl ketone production in E. coli and insights on the pathway from in vitro studies Citation Details In-Document Search Title: Substantial improvements in methyl ketone production in E. coli and insights on the pathway from in vitro studies Authors: Goh, Ee-Been ; Baidoo, Edward E.K. ; Burd, Helcio ; Lee, Taek Soon ; Keasling, Jay D. ; Beller, Harry R. Publication

  7. Natural little hierarchy for SUSY from radiative breaking of the

    Office of Scientific and Technical Information (OSTI)

    Peccei-Quinn symmetry (Journal Article) | SciTech Connect little hierarchy for SUSY from radiative breaking of the Peccei-Quinn symmetry Citation Details In-Document Search Title: Natural little hierarchy for SUSY from radiative breaking of the Peccei-Quinn symmetry Authors: Bae, Kyu Jung ; Baer, Howard ; Serce, Hasan Publication Date: 2015-01-06 OSTI Identifier: 1180704 Type: Publisher's Accepted Manuscript Journal Name: Physical Review D Additional Journal Information: Journal Volume: 91;

  8. Prospects for Higgs coupling measurements in SUSY with radiatively-driven

    Office of Scientific and Technical Information (OSTI)

    naturalness (Journal Article) | SciTech Connect Prospects for Higgs coupling measurements in SUSY with radiatively-driven naturalness Citation Details In-Document Search This content will become publicly available on August 13, 2016 Title: Prospects for Higgs coupling measurements in SUSY with radiatively-driven naturalness Authors: Bae, Kyu Jung ; Baer, Howard ; Nagata, Natsumi ; Serce, Hasan Publication Date: 2015-08-14 OSTI Identifier: 1210124 Type: Publisher's Accepted Manuscript Journal

  9. Implications of naturalness for the heavy Higgs bosons of supersymmetry

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Implications of naturalness for the heavy Higgs bosons of supersymmetry Citation Details In-Document Search Title: Implications of naturalness for the heavy Higgs bosons of supersymmetry Authors: Bae, Kyu Jung ; Baer, Howard ; Barger, Vernon ; Mickelson, Dan ; Savoy, Michael Publication Date: 2014-10-14 OSTI Identifier: 1181602 Type: Publisher's Accepted Manuscript Journal Name: Physical Review D Additional Journal Information: Journal Volume: 90; Journal

  10. Numerical Verification of Bounce Harmonic Resonances in Neoclassical Toroidal Viscosity for Tokamaks

    Office of Scientific and Technical Information (OSTI)

    7 PPPL- 4867 Numerical Verification of Bounce Harmonic Resonances in Neoclassical Toroidal Viscosity for Tokamaks April, 2013 Kimin Kim, Jong-Kyu Park and Allen H. Boozer Princeton Plasma Physics Laboratory Report Disclaimers Full Legal Disclaimer This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, nor any of their contractors, subcontractors or their

  11. (JS)_BL13 schedule S02-S03FY15HO3FINAL.xlsx

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    A Ogassawara 8855 A Ogassawara 3 3 0 Apr 6 7 8 9 10 11 12 Day Shift 6:00 AP AP 4281 A Cho 4281 A Cho 4281 A Cho 4281 A Cho 8073 A Ohldag 1 4 0 Night Shift 18:00 AP AP 4281 A Cho...

  12. Microsoft Word - $ASQrpt78028.DOC

    Office of Scientific and Technical Information (OSTI)

    Biofuel alternatives to ethanol: pumping the microbial well J.L. Fortman 1, 2* , Swapnil Chhabra 2, 3* , Aindrila Mukhopadhyay 2, 3* , Howard Chou 2, 4 , Taek Soon Lee 2, 3 , Eric Steen 2, 4 and Jay D. Keasling 1, 2, 3, 4 1 Department of Chemical Engineering, University of California, 717 Potter Street, Building 977, Mail code 3224 Berkeley, CA 94720-3224, USA 2 Joint BioEnergy Institute, Emeryville, CA 95608, USA 3 Physical Biosciences Division, Lawrence Berkeley National Laboratory, 717 Potter

  13. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Switch to Detail View for this search SciTech Connect Search Results Page 1 of 2 Search for: All records Creators/Authors contains: "Lee, Taek Soon" × Sort by Relevance Sort by Date (newest first) Sort by Date (oldest first) Sort by Relevance « Prev Select page number Go to page: 1 of 2 1 » Next » Everything12 Electronic Full Text7 Citations5 Multimedia0 Datasets0 Software0 Filter Results Filter by Subject ,2,5,5-tetramethyl-tetrahydrofuran (1) autoignition chemistry (1) biofuels

  14. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Switch to Detail View for this search SciTech Connect Search Results Page 2 of 2 Search for: All records Creators/Authors contains: "Lee, Taek Soon" × Sort by Relevance Sort by Date (newest first) Sort by Date (oldest first) Sort by Relevance « Prev Select page number Go to page: 2 of 2 2 » Next » Everything12 Electronic Full Text7 Citations5 Multimedia0 Datasets0 Software0 Filter Results Filter by Subject ,2,5,5-tetramethyl-tetrahydrofuran (1) autoignition chemistry (1) biofuels

  15. Mixed axion/gravitino dark matter from SUSY models with heavy axinos

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Mixed axion/gravitino dark matter from SUSY models with heavy axinos Citation Details In-Document Search This content will become publicly available on April 13, 2016 Title: Mixed axion/gravitino dark matter from SUSY models with heavy axinos Authors: Bae, Kyu Jung ; Baer, Howard ; Chun, Eung Jin ; Shin, Chang Sub Publication Date: 2015-04-14 OSTI Identifier: 1180909 Grant/Contract Number: doe-sc0010008; DOE-DE-SC0007897; DOE-ARRA- SC0003883 Type:

  16. Fail Safe Design for Large Capacity Lithium-ion Batteries

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Fail Safe Design for Large Capacity Lithium-ion Batteries NREL Commercialization & Tech Transfer Webinar March 27, 2011 Gi-Heon Kim gi-heon.kim@nrel.gov John Ireland, Kyu-Jin Lee, Ahmad Pesaran Kandler Smith kandler.smith@nrel.gov Source: A123 Source: GM NATIONAL RENEWABLE ENERGY LABORATORY Challenges for Large LIB Systems 2 * Li-ion batteries are flammable, require expensive manufacturing to reduce defects * Small-cell protection devices do not work for large systems * Difficult to detect

  17. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... Beroukhim, Rameen (1) Chaft, Jamie E. (1) Cho, Ahye (1) Cho, Jeonghee (1) Cohen, David W. (1) Costa, Daniel B. (Harvard-Med) (1) Eck , Michael J. (1) Ficarro, Scott B. (1) ...

  18. ALSNews Vol. 330

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    can be determined with picosecond resolution. Read more... Contact: Byoung-Ick Cho Genome Engineering with TAL Effector Nucleases In genome engineering, a single position...

  19. Summer 2004 Cyclotron Institute REU Program

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Habas; (Back row L to R) Mike Cho, Samuel Zenobia, Shalah Allison, Sarah Lumpkins, Nelson Martinez, Justin Rollins. Summer 2004 Student Presentations and Posters Shalah...

  20. LOWER BOUNDS ON MAGNETIC FIELDS IN INTERGALACTIC VOIDS FROM LONG...

    Office of Scientific and Technical Information (OSTI)

    Noji Higashi, Kusatsu, Shiga 525-8577 (Japan) Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Furo-cho, Chikusa-ku, Nagoya ...

  1. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... D. ; Bianchi, Andrea D. ; Ronning, Fillip ; Thompson, Joe D. ; Sarrao, John L. ; Cho, Jung Young ; Chan, Julia Y. ; Capan, Cigdem ; Fisk, Zachary The CeTIn5 superconductors (TCo, ...

  2. Search for: All records | DOE PAGES

    Office of Scientific and Technical Information (OSTI)

    ... Nature of the insulating ground state of the 5d postperovskite CaIrO3 Kim, Sun -Woo ; Liu, Chen ; Kim, Hyun -Jung ; Lee, Jun -Ho ; Yao, Yongxin ; Ho, Kai -Ming ; Cho, Jun -Hyung In ...

  3. The Biological Implications of the PP2A Crystal Structure

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    susceptibility to pathogen infections. To shed light on the details of how PP2A works, Cho and Xu have determined the first crystal structure of the enzyme. Their structure...

  4. kcho | The Ames Laboratory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    kcho Ames Laboratory Profile Kyuil Cho Asst Scientist III Division of Materials Science & Engineering A117 Zaffarano Phone Number: 515-294-4908 Email Address: kcho@ameslab.gov

  5. News Item

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    R. Tunuguntla, L. R. Comolli, F. I. Allen, A. V. Shnyrova, K. Rae Cho, D. Munoz, Y. M. Wang, C. P. Grigoropoulos, C. M. Ajo-Franklin, V. A. Frolov & A. Noy. Nature 2014 in...

  6. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... Neural Network (ANN) for Head and Neck Cancer Patients Cho, Daniel D ; Wernicke, A ... neural network (ANN) for head and neck cancer patients MaterialsMethods: An ANN can ...

  7. Complex States, Emergent Phenomena & Superconductivity in Intermetalli...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    expansion and lattice dynamics of RB66 compounds at low temperatures. Physics of the Solid State. 2014. 56, 2069-2076. Abstract Cho K ; Tanatar M A ; Ni N ; Prozorov R....

  8. ners-cp1-20130402104412

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    (2002). 3 N.Z. Cho, G.S. Lee, and C.J. Park, "Refinement of the 2-D1-D Fusion Method for 3-D Whole Core Transport Calculation," Trans Am. Nucl. Soc., 87, pp. 417-420...

  9. Microsoft Word - Awards_Final.docx

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    B-8 Aditya Mohite, C-PCSMPA-CINT Tie Wei, CCS-2 David Mascarenas, INST-OFF John Brady, MPA-11 Jeong-Hyun Cho, MPA-CINT Jared Crochet, MPA-CINTC-PCS Sara Kutchesfahani, N-4...

  10. SiC Power Module

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    479-575-7967 mantooth@uark.edu 3. Rohm Co., LTD 21 Saiin Mizosaki-cho, Ukyo-ku Kyoto, Japan 615-8585 Phone: Fax: 81 75 315 0172 Takukazu Otsuka, Engineer takukazu.otsuka@dsn.rohm...

  11. Mechanism of Methanol Synthesis on Cu through CO2 and CO Hydrogenation

    SciTech Connect (OSTI)

    Grabow, Lars C.; Mavrikakis, Manos

    2011-03-04

    We present a comprehensive mean-field microkinetic model for the methanol synthesis and water-gas-shift (WGS) reactions that includes novel reaction intermediates, such as formic acid (HCOOH) and hydroxymethoxy (CH?O?) and allows for the formation of formic acid (HCOOH), formaldehyde (CH?O), and methyl formate (HCOOCH?) as byproducts. All input model parameters were initially derived from periodic, self-consistent, GGA-PW91 density functional theory calculations on the Cu(111) surface and subsequently fitted to published experimentalmethanol synthesis rate data, which were collected under realistic conditions on a commercial Cu/ZnO/Al?O? catalyst. We find that the WGS reaction follows the carboxyl (COOH)-mediated path and that both CO and CO? hydrogenation pathways are active for methanol synthesis. Under typical industrial methanol synthesis conditions, CO? hydrogenation is responsible for ?2/3 of the methanol produced. The intermediates of the CO? pathway for methanol synthesis include HCOO*, HCOOH*, CH?O?*, CH?O*, and CH?O*. The formation of formate (HCOO*) from CO?* and H* on Cu(111) does not involve an intermediate carbonate (CO?*) species, and hydrogenation of HCOO* leads to HCOOH* instead of dioxymethylene (H?CO?*). The effect of CO is not only promotional; CO* is also hydrogenated in significant amounts to HCO*, CH?O *, CH?O*, and CH?OH*. We considered two possibilities for CO promotion: (a) removal of OH* via COOH* to form CO? and hydrogen (WGS), and (b) CO-assisted hydrogenation of various surface intermediates, with HCO* being the H-donor. Only the former mechanism contributes to methanol formation, but its effect is small compared with that of direct CO hydrogenation to methanol. Overall, methanol synthesis rates are limited by methoxy (CH?O*) formation at low CO?/(CO+CO?) ratios and by CH?O* hydrogenation in CO?-rich feeds. CH?O* hydrogenation is the common slow step for both the CO and the CO? methanol synthesis routes; the relative contribution of each route is determined by their respective slow steps HCO*+H*?CH?O*+* and HCOOH*+H*?CH?O?*+* as well as by feed composition and reaction conditions. An analysis of the fitted parameters for a commercial Cu/ZnO/Al?O? catalyst suggests that a more open Cu surface, for example, Cu(110), Cu(100), and Cu(211) partially covered by oxygen, may provide a better model for the active site of methanol synthesis, but our studies cannot exclude a synergistic effect with the ZnO support.

  12. Indexing Permafrost Soil Organic Matter Degradation Using High-Resolution Mass Spectrometry

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Mann, Benjamin F.; Chen, Hongmei; Herndon, Elizabeth M.; Chu, Rosalie K.; Tolic, Nikola; Portier, Evan F.; Roy Chowdhury, Taniya; Robinson, Errol W.; Callister, Stephen J.; Wullschleger, Stan D.; et al

    2015-06-12

    Microbial degradation of soil organic matter (SOM) is a key process for terrestrial carbon cycling, although the molecular details of these transformations remain unclear. This study reports the application of ultrahigh resolution mass spectrometry to profile the molecular composition of SOM and its degradation during a simulated warming experiment. A soil sample, collected near Barrow, Alaska, USA, was subjected to a 40-day incubation under anoxic conditions and analyzed before and after the incubation to determine changes of SOM composition. A CHO index based on molecular C, H, and O data was utilized to codify SOM components according to their observedmore » degradation potentials. Compounds with a CHO index score between –1 and 0 in a water-soluble fraction (WSF) demonstrated high degradation potential, with a highest shift of CHO index occurred in the N-containing group of compounds, while similar stoichiometries in a base-soluble fraction (BSF) did not. Additionally, compared with the classical H:C vs O:C van Krevelen diagram, CHO index allowed for direct visualization of the distribution of heteroatoms such as N in the identified SOM compounds. We demonstrate that CHO index is useful not only in characterizing arctic SOM at the molecular level but also enabling quantitative description of SOM degradation, thereby facilitating incorporation of the high resolution MS datasets to future mechanistic models of SOM degradation and prediction of greenhouse gas emissions.« less

  13. Indexing Permafrost Soil Organic Matter Degradation Using High-Resolution Mass Spectrometry

    SciTech Connect (OSTI)

    Mann, Benjamin F.; Chen, Hongmei; Herndon, Elizabeth M.; Chu, Rosalie K.; Tolic, Nikola; Portier, Evan F.; Roy Chowdhury, Taniya; Robinson, Errol W.; Callister, Stephen J.; Wullschleger, Stan D.; Graham, David E.; Liang, Liyuan; Gu, Baohua; Hui, Dafeng

    2015-06-12

    Microbial degradation of soil organic matter (SOM) is a key process for terrestrial carbon cycling, although the molecular details of these transformations remain unclear. This study reports the application of ultrahigh resolution mass spectrometry to profile the molecular composition of SOM and its degradation during a simulated warming experiment. A soil sample, collected near Barrow, Alaska, USA, was subjected to a 40-day incubation under anoxic conditions and analyzed before and after the incubation to determine changes of SOM composition. A CHO index based on molecular C, H, and O data was utilized to codify SOM components according to their observed degradation potentials. Compounds with a CHO index score between –1 and 0 in a water-soluble fraction (WSF) demonstrated high degradation potential, with a highest shift of CHO index occurred in the N-containing group of compounds, while similar stoichiometries in a base-soluble fraction (BSF) did not. Additionally, compared with the classical H:C vs O:C van Krevelen diagram, CHO index allowed for direct visualization of the distribution of heteroatoms such as N in the identified SOM compounds. We demonstrate that CHO index is useful not only in characterizing arctic SOM at the molecular level but also enabling quantitative description of SOM degradation, thereby facilitating incorporation of the high resolution MS datasets to future mechanistic models of SOM degradation and prediction of greenhouse gas emissions.

  14. A Study on Performance Degradation of PEMFC by Water Freezing | Department

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    of Energy A Study on Performance Degradation of PEMFC by Water Freezing A Study on Performance Degradation of PEMFC by Water Freezing Presentation by EunAe Cho to DOE's Fuel Cell Operations at Sub-Freezing Temperatures Workshop held February 1-5, 2005 in Phoenix, Arizona. PDF icon 11_cho_water.pdf More Documents & Publications Open Discussion of Freeze Related Issues Microsoft PowerPoint - USDOE-LANL Freeze Workshop.ppt Fundamental Issues in Subzero PEMFC Startup and Operation

  15. Laser activated diffuse discharge switch

    DOE Patents [OSTI]

    Christophorou, Loucas G. (Oak Ridge, TN); Hunter, Scott R. (Oak Ridge, TN)

    1988-01-01

    The invention is a gas mixture for a diffuse discharge switch which is capable of changing from a conducting state to an insulating state in the presence of electrons upon the introduction of laser light. The mixture is composed of a buffer gas such as nitrogen or argon and an electron attaching gas such as C.sub.6 H.sub.5 SH, C.sub.6 H.sub.5 SCH.sub.3, CH.sub.3 CHO and CF.sub.3 CHO wherein the electron attachment is brought on by indirect excitation of molecules to long-lived states by exposure to laser light.

  16. Catalytic reforming methods

    DOE Patents [OSTI]

    Tadd, Andrew R; Schwank, Johannes

    2013-05-14

    A catalytic reforming method is disclosed herein. The method includes sequentially supplying a plurality of feedstocks of variable compositions to a reformer. The method further includes adding a respective predetermined co-reactant to each of the plurality of feedstocks to obtain a substantially constant output from the reformer for the plurality of feedstocks. The respective predetermined co-reactant is based on a C/H/O atomic composition for a respective one of the plurality of feedstocks and a predetermined C/H/O atomic composition for the substantially constant output.

  17. The insecticide 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (DDT) alters the membrane raft location of the TSH receptor stably expressed in Chinese hamster ovary cells

    SciTech Connect (OSTI)

    De Gregorio, Francesca; Pellegrino, Mario; Picchietti, Simona; Belardinelli, Maria C.; Taddei, Anna Rita; Fausto, Anna Maria; Rossi, Mario; Maggio, Roberto; Giorgi, Franco

    2011-06-01

    DDT is a highly lipophilic molecule known to deplete membrane rafts of their phosphoglycolipid and cholesterol contents. However, we have recently shown that DDT can also alter the thyroid homeostasis by inhibiting TSH receptor (TSHr) internalization. The present study was undertaken to verify whether DDT goitrogenic effects are due to the insecticide acting directly on TSHr or via alteration of the membrane rafts hosting the receptor itself. Our results demonstrate that, in CHO-TSHr transfected cells, TSHr is activated in the presence of TSH, while it is inhibited following DDT exposure. DDT can also reduce the endocytic vesicular traffic, alter the extension of multi-branched microvilli along their plasma membranes and induce TSHr shedding in vesicular forms. To verify whether TSHr displacement might depend on DDT altering the raft constitution of CHO-TSHr cell membranes the extent of TSHr and lipid raft co-localization was examined by confocal microscopy. Evidence shows that receptor/raft co-localization increased significantly upon exposure to TSH, while receptors and lipid rafts become dislodged on opposite cell poles in DDT-exposed CHO-TSHr cells. As a control, under similar culturing conditions, diphenylethylene, which is known to be a lipophilic substance that is structurally related to DDT, did not affect the extent of TSHr and lipid raft co-localization in CHO-TSHr cells treated with TSH. These findings corroborate and extend our view that, in CHO cells, the DDT disrupting action on TSHr is primarily due to the insecticide acting on membranes to deplete their raft cholesterol content, and that the resulting inhibition on TSHr internalization is due to receptor dislodgement from altered raft microdomains of the plasma membrane. - Highlights: >DDT is a pesticide with a severe environmental impact >Epidemiologic correlation exists between exposition to DDT and thyroid dysfunction >DDT is a lipophilic molecule that has been shown to inhibit TSH receptor function >DDT depletes membrane raft cholesterol content and by this way inhibits TSH receptor

  18. Induction and Persistence of Large ?H2AX Foci by High Linear Energy Transfer Radiation in DNA-Dependent protein kinase–Deficient Cells

    SciTech Connect (OSTI)

    Bracalente, Candelaria; Ibañez, Irene L.; Molinari, Beatriz; Palmieri, Mónica; Kreiner, Andrés; Valda, Alejandro; and others

    2013-11-15

    Purpose: To evaluate the cell response to DNA double-strand breaks induced by low and high linear energy transfer (LET) radiations when the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs), an essential protein of the nonhomologous end-joining repair pathway, lacks kinase activity. Methods and Materials: CHO10B2, a Chinese hamster ovary cell line, and its derived radiosensitive mutant cell line, irs-20, lacking DNA-PKcs activity, were evaluated after 0 to 3 Gy of ?-rays, plateau and Bragg peak protons, and lithium beams by clonogenic assay, and as a measurement of double-strand breaks, phosphorylated H2AX (?H2AX) foci number and size were quantified by immunocytofluorescence. Results: Irs-20 exhibited greater radiosensitivity and a higher amount of ?H2AX foci than CHO10B2 at 6 hours after irradiation for all types of radiations. Remarkably, CHO10B2 and irs-20 maintained their difference in radiosensitivity after high-LET radiation. Six hours after low-LET radiations, irs-20 did not reach basal levels of ?H2AX at high doses, whereas CHO10B2 recovered basal levels for all doses. After high-LET radiation, only CHO10B2 exhibited a reduction in ?H2AX foci, but it never reached basal levels. Persistent foci in irs-20 confirmed a repair deficiency. Interestingly, after 30 minutes of high-LET radiation both cell lines exhibited large foci (size >0.9 ?m{sup 2}) related to the damage nature, whereas at 6 hours irs-20 showed a higher amount of large foci than CHO10B2, with a 7-fold increase at 3 Gy, that could also be associated to radiosensitivity. Conclusions: We demonstrated, for the first time, an association between deficient DNA-PKcs activity and not only high levels of H2AX phosphorylation but also persistence and size increase of ?H2AX foci after high-LET irradiation.

  19. Alkylation damage repair in mammalian genomes

    SciTech Connect (OSTI)

    Mitra, S.; Roy, R.; Kim, N.K. |; Tano, K. |; Ibeanu, G.C. |; Dunn, W.C.; Natarajan, A.T.; Hartenstein, B.; Kaina, B.

    1992-11-01

    The repair of O{sup 6} -alkylguanine in DNA involves only O{sup 6} -methyltransferase (MGMT) while the repair of N-alkylpurines requires multiple proteins including N-methylpurine-DNA glycosylase (MPG). While the biochemical properties human and mouse MGMTs are very similar, the mouse MPG removes 7-methylguanine more efficiently than the human protein. An increased level of MGMT, without a change in the level of MPG associated with gene amplification, was observed in a mouse cell line resistant to 2-chloroethyl-N-nitrosourea. In contrast, no correlation was observed between MPG level and resistance to methyl methanesulfonate in Chinese hamster ovary (CHO) cells. This result suggests a protein other than MPG limits the repair rate of N-alkylpurine in CHO cells.

  20. Alkylation damage repair in mammalian genomes

    SciTech Connect (OSTI)

    Mitra, S.; Roy, R.; Kim, N.K. . Sealy Center for Molecular Science Oak Ridge National Lab., TN ); Tano, K. Oak Ridge National Lab., TN ); Ibeanu, G.C. Oak Ridge National Lab., TN ); Dunn, W.C. (

    1992-01-01

    The repair of O{sup 6} -alkylguanine in DNA involves only O{sup 6} -methyltransferase (MGMT) while the repair of N-alkylpurines requires multiple proteins including N-methylpurine-DNA glycosylase (MPG). While the biochemical properties human and mouse MGMTs are very similar, the mouse MPG removes 7-methylguanine more efficiently than the human protein. An increased level of MGMT, without a change in the level of MPG associated with gene amplification, was observed in a mouse cell line resistant to 2-chloroethyl-N-nitrosourea. In contrast, no correlation was observed between MPG level and resistance to methyl methanesulfonate in Chinese hamster ovary (CHO) cells. This result suggests a protein other than MPG limits the repair rate of N-alkylpurine in CHO cells.

  1. New vector for transfer of yeast artificial chromosomes to mammalian cells

    SciTech Connect (OSTI)

    Markie, D.; Ragoussis, J.; Senger, G.; Rowan, A.; Trowsdale, J.; Sheer, D.; Bodmer, W.F. ); Sansom, D. )

    1993-03-01

    A modification vector has been constructed to facilitate the transfer of yeast artificial chromosomes (YACs) to mammalian cells in culture by targeting a dominant selectable marker (G418 resistance) to the right arm of pYAC4 clones. The ADE2 gene is used for yeast selection with consequent disruption of the URA3 gene, allowing direct modification of YACs within the common host strain AB1380, and providing a simple test for correct targeting. This vector has been tested by modification of a 550-kb YAC containing part of the human MHC class II region and transfer to CHO cells by protoplast fusion. Analysis of 15 independent G418-resistant CHO lines obtained following fusion suggests the majority contain a complete YAC with moderate amplification in some lines. 24 refs., 4 figs.

  2. ALSNews Vol. 330

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ALSNews Vol. 330 Print Ultrafast Spectroscopy of Warm Dense Matter So-called "warm dense matter" (neither solid, liquid, gas, nor plasma) tends to be drastically transient and difficult to study in the laboratory. Researchers have now demonstrated that, at the ALS, fast-changing electron temperatures of matter under extreme conditions can be determined with picosecond resolution. Read more... Contact: Byoung-Ick Cho Genome Engineering with TAL Effector Nucleases In genome engineering,

  3. Microsoft Word - Press Release_Kyonggi_Delegation_Jan2010.docx

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Delegation from Kyonggi University visiting LSU on January 14, 2010 Following a visit from Consul General Yun-soo Cho in December 2009 a high-ranking delegation from Kyonggi University, Suwan campus was visiting LSU on January 14, 2010. President Dr. Ho- joon Choi together with Dr. Hun Dae Lee, Dean for International Affairs and Director Young Duk Kim, Office of International Affairs, had the opportunity to tour LSU campus and discuss opportunities for collaborations ranging from student

  4. Principal component analysis of proteomics (PCAP) as a tool to direct

    Office of Scientific and Technical Information (OSTI)

    metabolic engineering (Journal Article) | SciTech Connect Journal Article: Principal component analysis of proteomics (PCAP) as a tool to direct metabolic engineering Citation Details In-Document Search Title: Principal component analysis of proteomics (PCAP) as a tool to direct metabolic engineering Authors: Alonso-Gutierrez, Jorge ; Kim, Eun-Mi ; Batth, Tanveer S. ; Cho, Nathan ; Hu, Qijun ; Chan, Leanne Jade G. ; Petzold, Christopher J. ; Hillson, Nathan J. ; Adams, Paul D. ; Keasling,

  5. Glucose-Neopentyl Glycol (GNG) amphiphiles for membrane protein study

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Glucose-Neopentyl Glycol (GNG) amphiphiles for membrane protein study Citation Details In-Document Search Title: Glucose-Neopentyl Glycol (GNG) amphiphiles for membrane protein study Authors: Chae, Pil Seok ; Rana, Rohini R. ; Gotfryd, Kamil ; Rasmussen, Søren G.F. ; Kruse, Andrew C. ; Cho, Kyung Ho ; Capaldi, Stefano ; Carlsson, Emil ; Kobilka, Brian ; Loland, Claus J. ; Gether, Ulrik ; Banerjee, Surajit ; Byrne, Bernadette ; Lee, John K. ; Gellman,

  6. (E)-4-[(4-nitrophenyl)diazenyl]phenyl anthracene-9-carboxylate.

    SciTech Connect (OSTI)

    Vance, Andrew L.; Zifer, Thomas; Nichol, Jessica L.; Rodriguez, Mark Andrew; Leonard, Francois Leonard; Wong, Bryan Matthew

    2008-10-01

    In the title compound, C{sub 27}H{sub 17}N{sub 3}O{sub 4}, the azo group displays a trans conformation and the dihedral angles between the central benzene ring and the pendant anthracene and nitrobenzene rings are 82.94 (7) and 7.30 (9){sup o}, respectively. In the crystal structure, weak C-H...O hydrogen bonds, likely associated with a dipole moment present on the molecule, help to consolidate the packing.

  7. EGG-M-90457 EGG-M--9045

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    EGG-M-90457 EGG-M--9045 7 A Paper Submi_ed for DE91 006149 AGENG 90 in West Ge,,_nany (Paper NO, F7,22) NON,-DESTRUCTIVE RIPENESS SENSING __-__ "4 _ _ B Y USING PROTON NMR _ _ _ _ _ _ _ ,. By. _' g''_ _=° " ! Seong In Cho /Research Engineer _ _ _ _ _ = _ A_riculmral Engineering, Purdue University _ "_ _,_-= _ i " _ West Lafayette, IN 47907,USA _ _= .:-_ * _ _= Gary W. Krutz/Professor _ _ _ Agricultural Engineering, Purdue University _ = _ i 8 = _._ _ __ West Lafayette, IN

  8. Hydrogenation of Single-walled Carbon Nanotubes

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Hydrogenation of Single-walled Carbon Nanotubes A. Nikitin1), H. Ogasawara1) D. Mann2), R. Denecke1)*, Z. Zhang3), H. Dai2), KJ Cho3), A. Nilsson1,4) 1Stanford Synchrotron Radiation Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA 2Department of Chemistry, Stanford University, Stanford, CA 94305, USA 3Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA 4FYSIKUM, Stockholm University, Albanova University Center, S-10691 Stockholm, Sweden In the next 20

  9. Functionalized polyfluorenes for use in optoelectronic devices

    DOE Patents [OSTI]

    Chichak, Kelly Scott; Lewis, Larry Neil; Cella, James Anthony; Shiang, Joseph John

    2011-11-08

    The present invention relates to process comprising reacting a polyfluorenes comprising at least one structural group of formula I ##STR00001## with an iridium (III) compound of formula II ##STR00002## wherein R.sup.1 and R.sup.2 are independently alkyl, substituted alkyl, aryl, substituted aryl or a combination thereof; R.sup.5is H or CHO; R.sup.3 and R.sup.4 are independently hydrogen, alkyl, substituted alkyl, aryl, substituted aryl or a combination thereof; R.sup.11 and R.sup.12 taken together form a substituted or unsubstituted monocyclic or bicyclic heteroaromatic ring; R.sup.13 is independently at each occurrence halo, nitro, hydroxy, amino, alkyl, aryl, arylalkyl, alkoxy, substituted alkoxy, substituted alkyl, substituted aryl, or substituted arylalkyl; Ar is aryl, heteroaryl, substituted aryl, substituted heteroaryl, or a combination thereof; X is selected from a direct bond, alky, substituted alkyl, and combinations thereof; Y is CHO or NH.sub.2; Z is CHO or NH.sub.2 where Z does not equal Y; and p is 0, 1 or 2. The invention also relates to the polyfluorenes, which are products of the reaction, and the use of the polyfluorenes in optoelectronic devices.

  10. Amperometric Choline Biosensor Fabricated through Electrostatic Assembly of Bienzyme/Polyelectrolyte Hybrid Layers on Carbon Nanotubes

    SciTech Connect (OSTI)

    Wang, Jun; Liu, Guodong; Lin, Yuehe

    2006-03-01

    We report a flow injection amperometric choline biosensors based on the electrostatic assembly of an enzyme of choline oxidase (ChO) and a bi-enzyme of ChO and horseradish peroxidase (HRP) onto multi-wall carbon nanotubes (MWCNT) modified glassy carbon (GC) electrodes. These choline biosensors were fabricated by immobilization of enzymes on the negatively charged MWCNT surface through alternatively assembling a cationic polydiallydiimethylammonium chloride (PDDA) layer and an enzyme layer. Using this layer-by-layer assembling approach, bioactive nanocomposite film of a PDDA/ChO/PDDA/HRP/PDDA/CNT (ChO/HRP/CNT) and a PDDA/ChO/PDDA/ CNT (ChO/ CNT) were fabricated on GC surface, respectively. Owning to the electrocatalytic effect of carbon nanotubes, the measurement of faradic responses resulting from enzymatic reactions has been realized at low potential with acceptable sensitivity. It is found the ChO/HRP/CNT biosensor is more sensitive than the ChO/CNT one. Experimental parameters affecting the sensitivity of biosensors, e.g. applied potential, flow rate, etc. were optimized and potential interference was examined. The response time for this choline biosensor is fast (less than a few seconds). The linear range of detection for the choline biosensor is from 5 x 10-5 to 5 x 10-3 M and the detection limit is determined to be about 1.0 x 10-5 M.

  11. Visible light-induced photocatalytic properties of WO{sub 3} films deposited by dc reactive magnetron sputtering

    SciTech Connect (OSTI)

    Imai, Masahiro; Kikuchi, Maiko; Oka, Nobuto; Shigesato, Yuzo

    2012-05-15

    The authors examined the photocatalytic activity of WO{sub 3} films (thickness 500-600 nm) deposited on a fused quartz substrate heated at 350-800 deg. C by dc reactive magnetron sputtering using a W metal target under the O{sub 2} gas pressure from 1.0 to 5.0 Pa. Films deposited at 800 deg. C under 5.0 Pa have excellent crystallinity of triclinic, P1(1) structure and a large surface area, as confirmed by x-ray diffraction, scanning electron microscopy, and atomic force microscopy. Exposure of acetaldehyde (CH{sub 3}CHO) adsorbed onto the film surface to ultraviolet, visible, or standard fluorescence light induces oxidative photocatalytic decomposition indicated by a decrease in CH{sub 3}CHO concentration and generation of CO{sub 2} gas. For all three types of irradiation, concentration ratio of decreased CH{sub 3}CHO to increased CO{sub 2} is about 1:1, suggesting the possible presence of intermediates. The sputter-deposited WO{sub 3} film can be a good candidate as a visible light-responsive photocatalyst.

  12. Volumetric Spectroscopic Imaging of Glioblastoma Multiforme Radiation Treatment Volumes

    SciTech Connect (OSTI)

    Parra, N. Andres; Maudsley, Andrew A.; Gupta, Rakesh K.; Ishkanian, Fazilat; Huang, Kris; Walker, Gail R.; Padgett, Kyle; Roy, Bhaswati; Panoff, Joseph; Markoe, Arnold; Stoyanova, Radka

    2014-10-01

    Purpose: Magnetic resonance (MR) imaging and computed tomography (CT) are used almost exclusively in radiation therapy planning of glioblastoma multiforme (GBM), despite their well-recognized limitations. MR spectroscopic imaging (MRSI) can identify biochemical patterns associated with normal brain and tumor, predominantly by observation of choline (Cho) and N-acetylaspartate (NAA) distributions. In this study, volumetric 3-dimensional MRSI was used to map these compounds over a wide region of the brain and to evaluate metabolite-defined treatment targets (metabolic tumor volumes [MTV]). Methods and Materials: Volumetric MRSI with effective voxel size of ∼1.0 mL and standard clinical MR images were obtained from 19 GBM patients. Gross tumor volumes and edema were manually outlined, and clinical target volumes (CTVs) receiving 46 and 60 Gy were defined (CTV{sub 46} and CTV{sub 60}, respectively). MTV{sub Cho} and MTV{sub NAA} were constructed based on volumes with high Cho and low NAA relative to values estimated from normal-appearing tissue. Results: The MRSI coverage of the brain was between 70% and 76%. The MTV{sub NAA} were almost entirely contained within the edema, and the correlation between the 2 volumes was significant (r=0.68, P=.001). In contrast, a considerable fraction of MTV{sub Cho} was outside of the edema (median, 33%) and for some patients it was also outside of the CTV{sub 46} and CTV{sub 60}. These untreated volumes were greater than 10% for 7 patients (37%) in the study, and on average more than one-third (34.3%) of the MTV{sub Cho} for these patients were outside of CTV{sub 60}. Conclusions: This study demonstrates the potential usefulness of whole-brain MRSI for radiation therapy planning of GBM and revealed that areas of metabolically active tumor are not covered by standard RT volumes. The described integration of MTV into the RT system will pave the way to future clinical trials investigating outcomes in patients treated based on metabolic information.

  13. Effects of arsenic on modification of promyelocytic leukemia (PML): PML responds to low levels of arsenite

    SciTech Connect (OSTI)

    Hirano, Seishiro; Watanabe, Takayuki; Kobayashi, Yayoi

    2013-12-15

    Inorganic arsenite (iAs{sup 3+}) is a two-edged sword. iAs{sup 3+} is a well-known human carcinogen; nevertheless, it has been used as a therapeutic drug for acute promyelocytic leukemia (APL), which is caused by a fusion protein comprising retinoic acid receptor-? and promyelocytic leukemia (PML). PML, a nuclear transcription factor, has a RING finger domain with densely positioned cysteine residues. To examine PML-modulated cellular responses to iAs{sup 3+}, CHO-K1 and HEK293 cells were each used to establish cell lines that expressed ectopic human PML. Overexpression of PML increased susceptibility to iAs{sup 3+} in CHO-K1 cells, but not in HEK293 cells. Exposure of PML-transfected cells to iAs{sup 3+} caused PML to change from a soluble form to less soluble forms, and this modification of PML was observable even with just 0.1 ?M iAs{sup 3+} (7.5 ppb). Western blot and immunofluorescent microscopic analyses revealed that the biochemical changes of PML were caused at least in part by conjugation with small ubiquitin-like modifier proteins (SUMOylation). A luciferase reporter gene was used to investigate whether modification of PML was caused by oxidative stress or activation of antioxidant response element (ARE) in CHO-K1 cells. Modification of PML protein occurred faster than activation of the ARE in response to iAs{sup 3+}, suggesting that PML was not modified as a consequence of oxidative stress-induced ARE activation. - Highlights: • PML was found in nuclear microspecles in response to arsenite. • Arsenite triggers SUMOylation of PML. • Arsenite modifies PML at as low as 0.1 ?M. • Modification of PML is not caused by ARE activation.

  14. Cell killing and mutation induction on Chinese hamster cells by photoradiations

    SciTech Connect (OSTI)

    Lam, C.K.C.

    1982-11-01

    Applying radiation directly on cells, far-uv is more effective than black light, and black light is more effective than white light in inducing proliferative death and in inducing resistance to 6-thioguanine (6-TG), ouabain and diptheria toxin (DT). Gold light has no killing and mutagenic effects on CHO (Chinese hamster ovary) cells. Use of filters showed that a small percentage of shorter wavelengths in the far-uv region is responsible for most of the killing and mutagenic effects in the unfiltered broad spectra of black and white light.

  15. Peel-and-Stick: Mechanism Study for Efficient Fabrication of

    Office of Scientific and Technical Information (OSTI)

    Flexible/Transparent Thin-film Electronics (Journal Article) | SciTech Connect Peel-and-Stick: Mechanism Study for Efficient Fabrication of Flexible/Transparent Thin-film Electronics Citation Details In-Document Search Title: Peel-and-Stick: Mechanism Study for Efficient Fabrication of Flexible/Transparent Thin-film Electronics Authors: Lee, C. H. ; Kim, J. H. ; Zou, C. Y. ; Cho, I. S. ; Weisse, J. M. ; Nemeth, W. ; Wang, Q. ; Van Duin, A. C. T. ; Kim, T. S. ; Zheng, X. L. Publication Date:

  16. Anomalous Transport in Sketched Nanostructures at the LaAlO3/SrTiO3

    Office of Scientific and Technical Information (OSTI)

    Interface (Journal Article) | SciTech Connect Anomalous Transport in Sketched Nanostructures at the LaAlO3/SrTiO3 Interface Citation Details In-Document Search Title: Anomalous Transport in Sketched Nanostructures at the LaAlO3/SrTiO3 Interface Authors: Cheng, Guanglei ; Veazey, Joshua P. ; Irvin, Patrick ; Cen, Cheng ; Bogorin, Daniela F. ; Bi, Feng ; Huang, Mengchen ; Lu, Shicheng ; Bark, Chung-Wung ; Ryu, Sangwoo ; Cho, Kwang-Hwan ; Eom, Chang-Beom ; Levy, Jeremy Publication Date:

  17. Structural and magnetic phase transitions in Ca 0.73 Le 0.27 FeAs 2 with

    Office of Scientific and Technical Information (OSTI)

    electron-overdoped FeAs layers (Journal Article) | DOE PAGES Structural and magnetic phase transitions in Ca 0.73 Le 0.27 FeAs 2 with electron-overdoped FeAs layers This content will become publicly available on February 25, 2017 « Prev Next » Title: Structural and magnetic phase transitions in Ca 0.73 Le 0.27 FeAs 2 with electron-overdoped FeAs layers Authors: Jiang, Shan ; Liu, Chang ; Cao, Huibo ; Birol, Turan ; Allred, Jared M. ; Tian, Wei ; Liu, Lian ; Cho, Kyuil ; Krogstad, Matthew

  18. Membranes Optimized for High Conductivity and Low Crossover of Redox Flow

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Cells 2015-033 - Energy Innovation Portal Energy Storage Energy Storage Find More Like This Return to Search Membranes Optimized for High Conductivity and Low Crossover of Redox Flow Cells 2015-033 Lawrence Berkeley National Laboratory Contact LBL About This Technology Publications: PDF Document Publication Tucker, M. C., Cho, K. T., Spingler, F. B., Weber, A. Z., Lin, G. "Impact of membrane characteristics on the performance and cycling of the Br2-H2 redox flow cell," Journal of

  19. Molecular Characterization of S- and N-containing Organic Constituents in Ambient Aerosols by negative ion mode High-Resolution Nanospray Desorption Electrospray Ionization Mass Spectrometry: CalNex 2010 field study

    SciTech Connect (OSTI)

    O'Brien, Rachel E.; Laskin, Alexander; Laskin, Julia; Rubitschun, Caitlin L.; Surratt, Jason D.; Goldstein, Allen H.

    2014-11-27

    Samples of ambient aerosols from the 2010 California Research at the Nexus of Air Quality and Climate Change (CalNex) field study were analyzed using Nanospray Desorption Electrospray Ionization High Resolution Mass Spectrometry (nano-DESI/MS). Four samples per day were collected in Bakersfield, CA on June 20-24 with a collection time of 6 hours per sample. Four characteristic groups of organic constituents were identified in the samples: compounds containing carbon, hydrogen, and oxygen only (CHO), sulfur- (CHOS), nitrogen-(CHON), and both nitrogen- and sulfur-containing organics (CHONS). Within the groups, organonitrates, organosulfates, and nitroxy organosulfates were assigned based on accurate mass measurements and elemental ratio comparisons. Changes in the chemical composition of the aerosol samples were observed throughout the day. The number of observed CHO compounds increased in the afternoon samples, suggesting regional photochemical processing as a source. The average number of CHOS compounds had the smallest changes throughout the day, consistent with a more broadly distributed source. Both of the nitrogen-containing groups (CHON and CHONS) had greater numbers of compounds in the night and morning samples, indicating that nitrate radical chemistry was likely a source for those compounds. Most of the compounds were found in submicron particles. The size distribution of CHON compounds was bimodal. We conclude that the majority of the compounds observed were secondary in nature with both biogenic and anthropogenic sources.

  20. Molecular Characterization of Organic Aerosol Using Nanospray Desorption/Electrospray Ionization Mass Spectrometry: CalNex 2010 field study

    SciTech Connect (OSTI)

    O'Brien, Rachel E.; Laskin, Alexander; Laskin, Julia; Liu, Shang; Weber, Robin; Russell, Lynn; Goldstein, Allen H.

    2013-04-01

    Aerosol samples from the CalNex 2010 field study were analyzed using high resolution mass spectrometry (HR-MS) coupled to a nanospray-desorption/electrospray ionization (nano-DESI) source. The samples were collected in Bakersfield, CA on June 22-23, 2010. The chemical formulas of over 1300 unique molecular species were detected in the mass range of 50-800 m/z. Our analysis focused on identification of two main groups: compounds containing only carbon, hydrogen, and oxygen (CHO only), and nitrogen-containing organic compounds (NOC). The NOC accounted for 35% (by number) of the compounds observed in the afternoon, and for 59% in the early morning samples. By comparing plausible reactant-product pairs, we propose that over 50% of the NOC in each sample could have been formed through reactions transforming carbonyls into imines. The CHO only compounds were dominant in the afternoon suggesting a photochemical source. The average O:C ratios of all observed compounds were fairly consistent throughout the day, ranging from 0.34 in the early morning to 0.37 at night. We conclude that both photooxidation and ammonia chemistry play important roles in forming the compounds observed in this mixed urban-rural environment.

  1. Insights into photodissociation dynamics of acetaldehyde from ab initio calculations and molecular dynamics simulations

    SciTech Connect (OSTI)

    Chen Shilu; Fang Weihai

    2009-08-07

    In the present paper we report a theoretical study on mechanistic photodissociation of acetaldehyde (CH{sub 3}CHO). Stationary structures for H{sub 2} and CO eliminations in the ground state (S{sub 0}) have been optimized with density functional theory method, which is followed by the intrinsic reaction coordinate and ab initio molecular dynamics calculations to confirm the elimination mechanism. Equilibrium geometries, transition states, and intersection structures for the C-C and C-H dissociations in excited states were determined by the complete-active-space self-consistent field (CASSCF) method. Based on the CASSCF optimized structures, the potential energy profiles for the dissociations were refined by performing the single-point calculations using the multireference configuration interaction method. Upon the low-energy irradiation of CH{sub 3}CHO (265 nm<{lambda}<318 nm), the T{sub 1} C-C bond fission following intersystem crossing from the S{sub 1} state is the predominant channel and the minor channel, the ground-state elimination to CH{sub 4}+CO after internal conversion (IC) from S{sub 1} to S{sub 0}, could not be excluded. With the photon energy increasing, another pathway of IC, achieved via an S{sub 1}/S{sub 0} intersection point resulting from the S{sub 1} C-C bond fission, becomes accessible and increases the yield of CH{sub 4}+CO.

  2. DOE/GO/15075-MacDiarmid-Wang Final Technical Report

    SciTech Connect (OSTI)

    Wang, Pen-Cheng

    2007-11-01

    Since Cho et al. reported up to ~8 wt% room-temperature hydrogen adsorption in HCl-treated polyaniline and polypyrrole [1], the research on the interactions between hydrogen and conducting polymers has become an area of special interest in the hydrogen economy community. However, later studies on hydrogen sorption using conducting polymers gave controversial results, which showed either much lower H2 uptake [2] or no H2 uptake at all [3]. As conducting polymers possess some unique “unconventional” and complex characteristics [4], it is highly likely that the controversial results could be attributed to the variation in material characteristics caused by “ambiguous” processing/handling procedures employed in H2 uptake studies involving conducting polymers. In order to determine whether conducting polymers can be developed into a new type of high-performance media for hydrogen storage applications, the goals of the project were to (i) confirm the brief report by Cho et al. [1] that ~8 wt% hydrogen gas storage in doped (metallic) forms of organic conducting polymers (“synthetic metals”), polyaniline and polypyrrole, can be attained, (ii) determine the optimum polymer preparative methods, chemical composition, polymer electrode potential, polymer crystallinity and morphology to give quantitative optimum conditions of hydrogen gas adsorption and desorption and (iii) investigate hydrogen storage by the many known types of organic conducting polymers in their semiconducting and, metallic forms, and in selected oxidation states.

  3. Correlation between human observer performance and model observer performance in differential phase contrast CT

    SciTech Connect (OSTI)

    Li, Ke; Garrett, John; Chen, Guang-Hong

    2013-11-15

    Purpose: With the recently expanding interest and developments in x-ray differential phase contrast CT (DPC-CT), the evaluation of its task-specific detection performance and comparison with the corresponding absorption CT under a given radiation dose constraint become increasingly important. Mathematical model observers are often used to quantify the performance of imaging systems, but their correlations with actual human observers need to be confirmed for each new imaging method. This work is an investigation of the effects of stochastic DPC-CT noise on the correlation of detection performance between model and human observers with signal-known-exactly (SKE) detection tasks.Methods: The detectabilities of different objects (five disks with different diameters and two breast lesion masses) embedded in an experimental DPC-CT noise background were assessed using both model and human observers. The detectability of the disk and lesion signals was then measured using five types of model observers including the prewhitening ideal observer, the nonprewhitening (NPW) observer, the nonprewhitening observer with eye filter and internal noise (NPWEi), the prewhitening observer with eye filter and internal noise (PWEi), and the channelized Hotelling observer (CHO). The same objects were also evaluated by four human observers using the two-alternative forced choice method. The results from the model observer experiment were quantitatively compared to the human observer results to assess the correlation between the two techniques.Results: The contrast-to-detail (CD) curve generated by the human observers for the disk-detection experiments shows that the required contrast to detect a disk is inversely proportional to the square root of the disk size. Based on the CD curves, the ideal and NPW observers tend to systematically overestimate the performance of the human observers. The NPWEi and PWEi observers did not predict human performance well either, as the slopes of their CD curves tended to be steeper. The CHO generated the best quantitative agreement with human observers with its CD curve overlapping with that of human observer. Statistical equivalence between CHO and humans can be claimed within 11% of the human observer results, including both the disk and lesion detection experiments.Conclusions: The model observer method can be used to accurately represent human observer performance with the stochastic DPC-CT noise for SKE tasks with sizes ranging from 8 to 128 pixels. The incorporation of the anatomical noise remains to be studied.

  4. Tumor Metabolism and Perfusion in Head and Neck Squamous Cell Carcinoma: Pretreatment Multimodality Imaging With {sup 1}H Magnetic Resonance Spectroscopy, Dynamic Contrast-Enhanced MRI, and [{sup 18}F]FDG-PET

    SciTech Connect (OSTI)

    Jansen, Jacobus F.A.; Schoeder, Heiko; Lee, Nancy Y.; Stambuk, Hilda E.; Wang Ya; Fury, Matthew G.; Patel, Senehal G.; Pfister, David G.; Shah, Jatin P.; Koutcher, Jason A.; Shukla-Dave, Amita

    2012-01-01

    Purpose: To correlate proton magnetic resonance spectroscopy ({sup 1}H-MRS), dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), and {sup 18}F-labeled fluorodeoxyglucose positron emission tomography ([{sup 18}F]FDG PET) of nodal metastases in patients with head and neck squamous cell carcinoma (HNSCC) for assessment of tumor biology. Additionally, pretreatment multimodality imaging was evaluated for its efficacy in predicting short-term response to treatment. Methods and Materials: Metastatic neck nodes were imaged with {sup 1}H-MRS, DCE-MRI, and [{sup 18}F]FDG PET in 16 patients with newly diagnosed HNSCC, before treatment. Short-term patient radiological response was evaluated at 3 to 4 months. Correlations among {sup 1}H-MRS (choline concentration relative to water [Cho/W]), DCE-MRI (volume transfer constant [K{sup trans}]; volume fraction of the extravascular extracellular space [v{sub e}]; and redistribution rate constant [k{sub ep}]), and [{sup 18}F]FDG PET (standard uptake value [SUV] and total lesion glycolysis [TLG]) were calculated using nonparametric Spearman rank correlation. To predict short-term responses, logistic regression analysis was performed. Results: A significant positive correlation was found between Cho/W and TLG ({rho} = 0.599; p = 0.031). Cho/W correlated negatively with heterogeneity measures of standard deviation std(v{sub e}) ({rho} = -0.691; p = 0.004) and std(k{sub ep}) ({rho} = -0.704; p = 0.003). Maximum SUV (SUVmax) values correlated strongly with MRI tumor volume ({rho} = 0.643; p = 0.007). Logistic regression indicated that std(K{sup trans}) and SUVmean were significant predictors of short-term response (p < 0.07). Conclusion: Pretreatment multimodality imaging using {sup 1}H-MRS, DCE-MRI, and [{sup 18}F]FDG PET is feasible in HNSCC patients with nodal metastases. Additionally, combined DCE-MRI and [{sup 18}F]FDG PET parameters were predictive of short-term response to treatment.

  5. Fluorescent detection of apoptotic cells using a family of zinc coordination complexes with selective affinity for membrane surfaces that are enriched with phosphatidylserine.

    SciTech Connect (OSTI)

    Smith, Bradley D.; Lambert, Timothy N.; Lakshmi, C.; Hanshaw, Roger, G.

    2005-03-01

    The appearance of phosphatidylserine on the membrane surface of apoptotic cells (Jurkat, CHO, HeLa) is monitored by using a family of bis(Zn{sup 2+}-2,2{prime}-dipicolylamine) coordination compounds with appended fluorescein or biotin groups as reporter elements. The phosphatidylserine affinity group is also conjugated directly to a CdSe/CdS quantum dot to produce a probe suitable for prolonged observation without photobleaching. Apoptosis can be detected under a wide variety of conditions, including variations in temperature, incubation time, and binding media. Binding of each probe appears to be restricted to the cell membrane exterior, because no staining of organelles or internal membranes is observed.

  6. Experimental and ab initio study of the photofragmentation of DNA and RNA sugars

    SciTech Connect (OSTI)

    Ha, D. T.; Huels, M. A.; Huttula, M.; Urpelainen, S.; Kukk, E.

    2011-09-15

    The photoelectron-photoion-photoion coincidence method is used to measure the photodissociation of doubly charged D-ribose (C{sub 5}H{sub 10}O{sub 5}), the RNA sugar molecules, and 2-deoxy-D-ribose (C{sub 5}H{sub 10}O{sub 4}), the DNA sugar molecules, following normal Auger decay after initial C 1s and O 1s core ionizations. The fragment identification is facilitated by measuring isotopically labeled D-ribose, such as D-ribose deuterated at C(1), and with {sup 13}C at the C(5) position. Ab initio quantum chemistry calculations are used to gain further insight into the abundant appearance of the CHO{sup +} fragment.

  7. Synthesis and crystal structure of α,β-unsaturated ketone: 3,3′-[1,2-ethanediylbis(oxy-2,1-phenylene)]bis[1-(2-pyridyl) -2-propen-1-one

    SciTech Connect (OSTI)

    Wang, G.-F. Gong, Q.-J. Sun, H.; Yao, C-Z.

    2013-12-15

    The title compound, C{sub 30}H{sub 24}N{sub 2}O{sub 4}, 3,3′-[1,2-ethanediyl-bis(oxy-2,1-phenylene)]bis[1-(2-pyridyl) -2-propen-1-one] was synthesized and characterized by elemental analysis, FT-IR spectra, {sup 1}H NMR, and X-ray single-crystal diffraction. In the molecule, the pyridine plane and the adjacent phenyl plane are almost coplanar with the dihedral angle of 3.07°, while the dihedral angle between the mean planes of the two asymmetric units is 67.56°. The crystal packing is stabilized by weak intermolecular C-H...N and C-H...O hydrogen bonds, C-H...π and π...π stacking interactions.

  8. Layer-by-Layer Assembly of Enzymes on Carbon Nanotubes

    SciTech Connect (OSTI)

    Wang, Jun; Liu, Guodong; Lin, Yuehe

    2008-06-01

    The use of Layer-by-layer techniques for immobilizing several types of enzymes, e.g. glucose oxidase (GOx), horse radish oxidases(HRP), and choline oxidase(CHO) on carbon nanotubes and their applications for biosenseing are presented. The enzyme is immobilized on the negatively charged CNT surface by alternatively assembling a cationic polydiallyldimethyl-ammonium chloride (PDDA) layer and a enzyme layer. The sandwich-like layer structure (PDDA/enzyme/PDDA/CNT) formed by electrostatic assembling provides a favorable microenvironment to keep the bioactivity of enzyme and to prevent enzyme molecule leakage. The morphologies and electrocatalytic acitivity of the resulted enzyme film were characterized using TEM and electrochemical techniques, respectively. It was found that these enzyme-based biosensors are very sensitive, selective for detection of biomolecules, e.g. glucose, choline.

  9. Crystal structure of 1-methyl-3-([2,2-dimethyl-4,6-dioxo-1,3-dioxane-5-ylidene]methyl)urea

    SciTech Connect (OSTI)

    Habibi, A. Ghorbani, H. S.; Bruno, G.; Rudbari, H. A.; Valizadeh, Y.

    2013-12-15

    The crystal structure of 1-Methyl-3-([2,2-dimethyl-4,6-dioxo-1,3-dioxane-5-ylidene]methyl)urea (C{sub 9}H{sub 12}N{sub 2}O{sub 5}) has been determined by single crystal X-ray diffraction analysis. The crystals are monoclinic, a = 5.3179(2), b = 18.6394(6), c =10.8124(3) Å, ? = 100.015(2)°, Z = 4, sp. gr. P2{sub 1}/c, R = 0.0381 for 2537 reflections with I > 2?(I). Except for C(CH{sub 3}){sub 2} group, the molecule is planar. The structure is stabilized by inter- and intramolecular N-H...O hydrogen bonds and weak C-H...O interactions.

  10. Reduction of Carbon Monoxide. Past Research Summary

    DOE R&D Accomplishments [OSTI]

    Schrock, R. R.

    1982-01-01

    Research programs for the year on the preparation, characterization, and reactions of binuclear tantalum complexes are described. All evidence to date suggest the following of these dimeric molecules: (1) the dimer does not break into monomers under mild conditions; (2) intermolecular hydride exchange is not negligible, but it is slow; (3) intermolecular non-ionic halide exchange is fast; (4) the ends of the dimers can rotate partially with respect to one another. The binuclear tantalum hydride complexes were found to react with carbon monoxide to give a molecule which is the only example of reduction of CO by a transition metal hydride to give a complex containing a CHO ligand. Isonitrides also reacted in a similar manner with dimeric tantalum hydride. (ATT)

  11. Lipocalin 2 regulation by thermal stresses: Protective role of Lcn2/NGAL against cold and heat stresses

    SciTech Connect (OSTI)

    Roudkenar, Mehryar Habibi, E-mail: roudkenar@ibto.ir [Research Center, Iranian Blood Transfusion Organization, Tehran (Iran, Islamic Republic of); Halabian, Raheleh [Research Center, Iranian Blood Transfusion Organization, Tehran (Iran, Islamic Republic of)] [Research Center, Iranian Blood Transfusion Organization, Tehran (Iran, Islamic Republic of); Roushandeh, Amaneh Mohammadi [Department of Anatomy, Faculty of Medicine, Medical University of Tabriz, Tabriz (Iran, Islamic Republic of)] [Department of Anatomy, Faculty of Medicine, Medical University of Tabriz, Tabriz (Iran, Islamic Republic of); Nourani, Mohammad Reza [Chemical Injury Research Center, Baqiyatallah Medical Science University, Tehran (Iran, Islamic Republic of)] [Chemical Injury Research Center, Baqiyatallah Medical Science University, Tehran (Iran, Islamic Republic of); Masroori, Nasser [Research Center, Iranian Blood Transfusion Organization, Tehran (Iran, Islamic Republic of)] [Research Center, Iranian Blood Transfusion Organization, Tehran (Iran, Islamic Republic of); Ebrahimi, Majid [Research Center, Iranian Blood Transfusion Organization, Tehran (Iran, Islamic Republic of) [Research Center, Iranian Blood Transfusion Organization, Tehran (Iran, Islamic Republic of); Chemical Injury Research Center, Baqiyatallah Medical Science University, Tehran (Iran, Islamic Republic of); Nikogoftar, Mahin; Rouhbakhsh, Mehdi; Bahmani, Parisa [Research Center, Iranian Blood Transfusion Organization, Tehran (Iran, Islamic Republic of)] [Research Center, Iranian Blood Transfusion Organization, Tehran (Iran, Islamic Republic of); Najafabadi, Ali Jahanian [Department of Molecular Biology, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of)] [Department of Molecular Biology, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of); Shokrgozar, Mohammad Ali [National Cell Bank of Iran, Pasteur institute of Iran, Tehran (Iran, Islamic Republic of)] [National Cell Bank of Iran, Pasteur institute of Iran, Tehran (Iran, Islamic Republic of)

    2009-11-01

    Environmental temperature variations are the most common stresses experienced by a wide range of organisms. Lipocalin 2 (Lcn2/NGAL) is expressed in various normal and pathologic conditions. However, its precise functions have not been fully determined. Here we report the induction of Lcn2 by thermal stresses in vivo, and its role following exposure to cold and heat stresses in vitro. Induction of Lcn2 in liver, heart and kidney was detected by RT-PCR, Western blot and immunohistochemistry following exposure of mice to heat and cold stresses. When CHO and HEK293T cells overexpressing NGAL were exposed to cold stress, cell proliferation was higher compared to controls. Down-regulatrion of NGAL by siRNA in A549 cells resulted in less proliferation when exposed to cold stress compared to control cells. The number of apoptotic cells and expression of pro-apoptotic proteins were lower in the NGAL overexpressing CHO and HEK293T cells, but were higher in the siRNA-transfected A549 cells compared to controls, indicating that NGAL protects cells against cold stress. Following exposure of the cells to heat stress, ectopic expression of NGAL protected cells while addition of exogenous recombinant NGAL to the cell culture medium exacerbated the toxicity of heat stress specially when there was low or no endogenous expression of NGAL. It had a dual effect on apoptosis following heat stress. NGAL also increased the expression of HO-1. Lcn2/NGAL may have the potential to improve cell proliferation and preservation particularly to prevent cold ischemia injury of transplanted organs or for treatment of some cancers by hyperthermia.

  12. Low temperature (550-700 K) oxidation pathways of cyclic ketones: Dominance of HO2-elimination channels yielding conjugated cyclic coproducts

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Scheer, Adam M.; Welz, Oliver; Vasu, Subith S.; Osborn, David L.; Taatjes, Craig A.

    2015-04-13

    The low-temperature oxidation of three cyclic ketones, cyclopentanone (CPO; C5H8O), cyclohexanone (CHO; C6H10 O), and 2-methyl-cyclopentanone (2-Me-CPO; CH3–C5H7 O), is studied between 550 and 700 K and at 4 or 8 Torr total pressure. Initial fuel radicals R are formedvia fast H-abstraction from the ketones by laser-photolytically generated chlorine atoms. Intermediates and products from the subsequent reactions of these radicals in the presence of excess O2 are probed with time and isomeric resolution using multiplexed photoionization mass spectrometry with tunable synchrotron ionizing radiation. For CPO and CHO the dominant product channel in the R + O2 reactions is chain-terminating HO2-eliminationmore » yielding the conjugated cyclic coproducts 2-cyclopentenone and 2-cyclohexenone, respectively. Results on oxidation of 2-Me-CPO also show a dominant contribution from HO2-elimination. Moreover, the photoionization spectrum of the co-product suggests formation of 2-methyl-2-cyclopentenone and/or 2-cyclohexenone, resulting from a rapid Dowd–Beckwith rearrangement, preceding addition to O2, of the initial (2-oxocyclopentyl)methyl radical to 3-oxocyclohexyl. Cyclic ethers, markers for hydroperoxyalkyl radicals (QOOH), key intermediates in chain-propagating and chain-branching low-temperature combustion pathways, are only minor products. The interpretation of the experimental results is supported by stationary point calculations on the potential energy surfaces of the associated R + O2 reactions at the CBS-QB3 level. Furthermore, the calculations indicate that HO2-elimination channels are energetically favored and product formation via QOOH is disfavored. Lastly, the prominence of chain-terminating pathways linked with HO2 formation in low-temperature oxidation of cyclic ketones suggests little low-temperature reactivity of these species as fuels in internal combustion engines.« less

  13. TH-A-BRF-09: Integration of High-Resolution MRSI Into Glioblastoma Treatment Planning

    SciTech Connect (OSTI)

    Schreibmann, E; Cordova, J; Shu, H; Crocker, I; Curran, W; Holder, C; Shim, H

    2014-06-15

    Purpose: Identification of a metabolite signature that shows significant tumor cell infiltration into normal brain in regions that do not appear abnormal on standard MRI scans would be extremely useful for radiation oncologists to choose optimal regions of brain to treat, and to quantify response beyond the MacDonald criteria. We report on integration of high-resolution magnetic resonance spectroscopic imaging (HR-MRSI) with radiation dose escalation treatment planning to define and target regions at high risk for recurrence. Methods: We propose to supplement standard MRI with a special technique performed on an MRI scanner to measure the metabolite levels within defined volumes. Metabolite imaging was acquired using an advanced MRSI technique combining 3D echo-planar spectroscopic imaging (EPSI) with parallel acquisition (GRAPPA) using a multichannel head coil that allows acquisition of whole brain metabolite maps with 108 μl resolution in 12 minutes implemented on a 3T MR scanner. Elevation in the ratio of two metabolites, choline (Cho, elevated in proliferating high-grade gliomas) and N-acetyl aspartate (NAA, a normal neuronal metabolite), was used to image infiltrating high-grade glioma cells in vivo. Results: The metabolite images were co-registered with standard contrast-enhanced T1-weighted MR images using in-house registration software and imported into the treatment-planning system. Regions with tumor infiltration are identified on the metabolic images and used to create adaptive IMRT plans that deliver a standard dose of 60 Gy to the standard target volume and an escalated dose of 75 Gy (or higher) to the most suspicious regions, identified as areas with elevated Cho/NAA ratio. Conclusion: We have implemented a state-of-the-art HR-MRSI technology that can generate metabolite maps of the entire brain in a clinically acceptable scan time, coupled with introduction of an imaging co-registration/ analysis program that combines MRSI data with standard imaging studies in a clinically useful fashion.

  14. FORMATION OF PEPTIDE BONDS IN SPACE: A COMPREHENSIVE STUDY OF FORMAMIDE AND ACETAMIDE IN Sgr B2(N)

    SciTech Connect (OSTI)

    Halfen, D. T.; Ziurys, L. M.; Ilyushin, V. E-mail: lziurys@as.arizona.edu

    2011-12-10

    Extensive observations of acetamide (CH{sub 3}CONH{sub 2}) and formamide (NH{sub 2}CHO) have been conducted toward Sgr B2(N) at 1, 2, and 3 mm using the Submillimeter Telescope (SMT) and the 12 m antenna of the Arizona Radio Observatory. Over the frequency range 65-280 GHz, 132 transitions of acetamide have been observed as individual, distinguishable features, although in some cases they are partially blended. The unblended transitions in acetamide indicate V{sub LSR} = 63.2 {+-} 2.8 km s{sup -1} and {Delta}V{sub 1/2} = 12.5 {+-} 2.9 km s{sup -1}, line parameters that are very similar to that of formamide (NH{sub 2}CHO) and other organic species in Sgr B2(N). For formamide, 79 individual transitions were identified over the same frequency region. Rotational diagram analyses indicate the presence of two components for both species in Sgr B2(N). For acetamide, the colder component (E{sub u} < 40 K) exhibits a rotational temperature of T{sub rot} = 17 {+-} 4 K and a column density of N{sub tot} = 5.2 {+-} 3.5 Multiplication-Sign 10{sup 13} cm{sup -2}; the higher energy component has T{sub rot} = 171 {+-} 4 K and N{sub tot} = 6.4 {+-} 4.7 Multiplication-Sign 10{sup 14} cm{sup -2}. In the case of formamide, T{sub rot} = 26 {+-} 4 K and N{sub tot} = 1.6 {+-} 0.7 Multiplication-Sign 10{sup 14} cm{sup -2} for the colder component with T{sub rot} = 134 {+-} 17 K and N{sub tot} = 4.0 {+-} 1.2 Multiplication-Sign 10{sup 14} cm{sup -2} for the warmer region. The fractional abundances of acetamide are f (H{sub 2}) = 1.7 Multiplication-Sign 10{sup -11} and 2.1 Multiplication-Sign 10{sup -10} for the cold and warm components, and in formamide, f (H{sub 2}) = 5.3 Multiplication-Sign 10{sup -11} and 1.3 Multiplication-Sign 10{sup -10}. The similarity between the abundances and distributions of CH{sub 3}CONH{sub 2} and NH{sub 2}CHO suggests a synthetic connection. The abundance of acetamide, moreover, is only a factor of three lower than that of formaldehyde, and very similar to acetaldehyde and ketene. CH{sub 3}CONH{sub 2} is therefore one of the most abundant complex organic species in Sgr B2(N), and could be a possible source of larger peptide molecules, as opposed to amino acids.

  15. Histamine acting on H1 receptor promotes inhibition of proliferation via PLC, RAC, and JNK-dependent pathways

    SciTech Connect (OSTI)

    Notcovich, Cintia; Laboratorio de Farmacologia de Receptores, Catedra de Quimica Medicinal, Departamento de Farmacologia, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires ; Diez, Federico; Tubio, Maria Rosario; Laboratorio de Farmacologia de Receptores, Catedra de Quimica Medicinal, Departamento de Farmacologia, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires ; Baldi, Alberto; Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires ; Kazanietz, Marcelo G.; Davio, Carlos; Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires ; Shayo, Carina; Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires

    2010-02-01

    It is well established that histamine modulates cell proliferation through the activation of the histamine H1 receptor (H1R), a G protein-coupled receptor (GPCR) that is known to couple to phospholipase C (PLC) activation via Gq. In the present study, we aimed to determine whether H1R activation modulates Rho GTPases, well-known effectors of Gq/G{sub 11}-coupled receptors, and whether such modulation influences cell proliferation. Experiments were carried out in CHO cells stably expressing H1R (CHO-H1R). By using pull-down assays, we found that both histamine and a selective H1R agonist activated Rac and RhoA in a time- and dose-dependent manner without significant changes in the activation of Cdc42. Histamine response was abolished by the H1R antagonist mepyramine, RGS2 and the PLC inhibitor U73122, suggesting that Rac and RhoA activation is mediated by H1R via Gq coupling to PLC stimulation. Histamine caused a marked activation of serum response factor activity via the H1R, as determined with a serum-responsive element (SRE) luciferase reporter, and this response was inhibited by RhoA inactivation with C3 toxin. Histamine also caused a significant activation of JNK which was inhibited by expression of the Rac-GAP {beta}2-chimaerin. On the other hand, H1R-induced ERK1/2 activation was inhibited by U73122 but not affected by C3 or {beta}2-chimaerin, suggesting that ERK1/2 activation was dependent on PLC and independent of RhoA or Rac. [{sup 3}H]-Thymidine incorporation assays showed that both histamine and the H1R agonist inhibited cell proliferation in a dose-dependent manner and that the effect was independent of RhoA but partially dependent on JNK and Rac. Our results reveal that functional coupling of the H1R to Gq-PLC leads to the activation of RhoA and Rac small GTPases and suggest distinct roles for Rho GTPases in the control of cell proliferation by histamine.

  16. Prominin-2 expression increases protrusions, decreases caveolae and inhibits Cdc42 dependent fluid phase endocytosis

    SciTech Connect (OSTI)

    Singh, Raman Deep Schroeder, Andreas S.; Scheffer, Luana; Holicky, Eileen L.; Wheatley, Christine L.; Marks, David L. Pagano, Richard E.

    2013-05-10

    Highlights: •Prominin-2 expression induced protrusions that co-localized with lipid raft markers. •Prominin-2 expression decreased caveolae, caveolar endocytosis and increased pCav1. •Prominin-2 expression inhibited fluid phase endocytosis by inactivation of Cdc42. •These endocytic effects can be reversed by adding exogenous cholesterol. •Caveolin1 knockdown restored fluid phase endocytosis in Prominin2 expressing cells. -- Abstract: Background: Membrane protrusions play important roles in biological processes such as cell adhesion, wound healing, migration, and sensing of the external environment. Cell protrusions are a subtype of membrane microdomains composed of cholesterol and sphingolipids, and can be disrupted by cholesterol depletion. Prominins are pentaspan membrane proteins that bind cholesterol and localize to plasma membrane (PM) protrusions. Prominin-1 is of great interest as a marker for stem and cancer cells, while Prominin-2 (Prom2) is reportedly restricted to epithelial cells. Aim: To characterize the effects of Prom-2 expression on PM microdomain organization. Methods: Prom2-fluorescent protein was transfected in human skin fibroblasts (HSF) and Chinese hamster ovary (CHO) cells for PM raft and endocytic studies. Caveolae at PM were visualized using transmission electron microscopy. Cdc42 activation was measured and caveolin-1 knockdown was performed using siRNAs. Results: Prom2 expression in HSF and CHO cells caused extensive Prom2-positive protrusions that co-localized with lipid raft markers. Prom2 expression significantly decreased caveolae at the PM, reduced caveolar endocytosis and increased caveolin-1 phosphorylation. Prom2 expression also inhibited Cdc42-dependent fluid phase endocytosis via decreased Cdc42 activation. Effects on endocytosis were reversed by addition of cholesterol. Knockdown of caveolin-1 by siRNA restored Cdc42 dependent fluid phase endocytosis in Prom2-expressing cells. Conclusions: Prom2 protrusions primarily localize to lipid rafts and recruit cholesterol into protrusions and away from caveolae, leading to increased phosphorylation of caveolin-1, which inhibits Cdc42-dependent endocytosis. This study provides a new insight for the role for prominins in the regulation of PM lipid organization.

  17. Final Technical Report "Catalytic Hydrogenation of Carbon Monoxide and Olefin Oxidation" Grant number : DE-FG02-86ER13615

    SciTech Connect (OSTI)

    Wayland, B.B.

    2009-08-31

    Title: Catalytic Hydrogenation of Carbon Monoxide and Olefin Oxidation Grant No. DE-FG02-86ER13615 PI: Wayland, B. B. (wayland@sas.upenn.edu) Abstract Development of new mechanistic strategies and catalyst materials for activation of CO, H2, CH4, C2H4, O2, and related substrates relevant to the conversion of carbon monoxide, alkanes, and alkenes to organic oxygenates are central objectives encompassed by this program. Design and synthesis of metal complexes that manifest reactivity patterns associated with potential pathways for the hydrogenation of carbon monoxide through metallo-formyl (M-CHO), dimetal ketone (M-C(O)-M), and dimetal dionyl (M-C(O)-C(O)-M) species is one major focus. Hydrocarbon oxidation using molecular oxygen is a central goal for methane activation and functionalization as well as regioselective oxidation of olefins. Discovery of new reactivity patterns and control of selectivity are pursued through designing new metal complexes and adjusting reaction conditions. Variation of reaction media promotes distinct reaction pathways that control both reaction rates and selectivities. Dimetalloradical diporphyrin complexes preorganize transition states for substrate reactions that involve two metal centers and manifest large rate increases over mono-metalloradical reactions of hydrogen, methane, and other small molecule substrates. Another broad goal and recurring theme of this program is to contribute to the thermodynamic database for a wide scope of organo-metal transformations in a range of reaction media. One of the most complete descriptions of equilibrium thermodynamics for organometallic reactions in water and methanol is emerging from the study of rhodium porphyrin substrate reactions in aqueous and alcoholic media. Water soluble group nine metalloporphyrins manifest remarkably versatile substrate reactivity in aqueous and alcoholic media which includes producing rhodium formyl (Rh-CHO) and hydroxy methyl (Rh-CH2OH) species. Exploratory directions for this program include expending new strategies for anti-Markovnikov addition of water, alcohols, and amines with olefins, developing catalytic reactions of CO to give formamides and formic esters, and evaluating the potential for coupling reactions of CO to produce organic building blocks.

  18. Higher coronary heart disease and heart attack morbidity in Appalachian coal mining regions

    SciTech Connect (OSTI)

    Hendryx, M.; Zullig, K.J.

    2009-11-15

    This study analyzes the U.S. 2006 Behavioral Risk Factor Surveillance System survey data (N = 235,783) to test whether self-reported cardiovascular disease rates are higher in Appalachian coal mining counties compared to other counties after control for other risks. Dependent variables include self-reported measures of ever (1) being diagnosed with cardiovascular disease (CVD) or with a specific form of CVD including (2) stroke, (3) heart attack, or (4) angina or coronary heart disease (CHD). Independent variables included coal mining, smoking, BMI, drinking, physician supply, diabetes co-morbidity, age, race/ethnicity, education, income, and others. SUDAAN Multilog models were estimated, and odds ratios tested for coal mining effects. After control for covariates, people in Appalachian coal mining areas reported significantly higher risk of CVD (OR = 1.22, 95% CI = 1.14-1.30), angina or CHO (OR = 1.29, 95% C1 = 1.19-1.39) and heart attack (OR = 1.19, 95% C1 = 1.10-1.30). Effects were present for both men and women. Cardiovascular diseases have been linked to both air and water contamination in ways consistent with toxicants found in coal and coal processing. Future research is indicated to assess air and water quality in coal mining communities in Appalachia, with corresponding environmental programs and standards established as indicated.

  19. Crosslinked Polyamide

    DOE Patents [OSTI]

    Huang, Zhi H.; McDonald, William F.; Wright, Stacy C.; Taylor, Andrew C.

    2002-06-04

    A crosslinked polyamide material and a process for preparing the crosslinked polyamide material are disclosed. The crosslinked polyamide material comprises a crosslinked chemical combination of (1) a polyamide of the formula: ##STR1## wherein n is between about 50 and 10,000, wherein each R is between 1 and 50 carbon atoms alone and is optionally substituted with heteroatoms, oxygen, nitrogen, sulfur, or phosphorus and combinations thereof, wherein multiple of the R are in vertically aligned spaced relationship along a backbone forming the polyamide, and wherein two or more of the R contain an amino group; and (2) a crosslinking agent containing at least two functional groups capable of reacting with the amino groups of the polyamide. In one embodiment of the invention, the crosslinking agent is an aliphatic or aromatic isocyanate compound having 2 or more --N.dbd.C.dbd.O groups. In another embodiment of the invention, the crosslinking agent is an aliphatic aldehyde or aromatic aldehyde compound having 2 or more --CHO groups. In still another embodiment of the invention, the crosslinking agent is selected from a phosphine having the general formula (A).sub.2 P(B) and mixtures thereof, wherein A is hydroxyalkyl, and B is hydroxyalkyl, alkyl, or aryl. In yet another embodiment of the invention, the crosslinking agent is selected from the group consisting of epoxy resins having more than one epoxide group per molecule.

  20. Dissociative electron attachments to ethanol and acetaldehyde: A combined experimental and simulation study

    SciTech Connect (OSTI)

    Wang, Xu-Dong; Xuan, Chuan-Jin; Feng, Wen-Ling; Tian, Shan Xi

    2015-02-14

    Dissociation dynamics of the temporary negative ions of ethanol and acetaldehyde formed by the low-energy electron attachments is investigated by using the anion velocity map imaging technique and ab initio molecular dynamics simulations. The momentum images of the dominant fragments O{sup ?}/OH{sup ?} and CH{sub 3}{sup ?} are recorded, indicating the low kinetic energies of O{sup ?}/OH{sup ?} for ethanol while the low and high kinetic energy distributions of O{sup ?} ions for acetaldehyde. The CH{sub 3}{sup ?} image for acetaldehyde also shows the low kinetic energy. With help of the dynamics simulations, the fragmentation processes are qualitatively clarified. A new cascade dissociation pathway to produce the slow O{sup ?} ion via the dehydrogenated intermediate, CH{sub 3}CHO{sup ?} (acetaldehyde anion), is proposed for the dissociative electron attachment to ethanol. After the electron attachment to acetaldehyde molecule, the slow CH{sub 3}{sup ?} is produced quickly in the two-body dissociation with the internal energy redistributions in different aspects before bond cleavages.

  1. Comparative Density Functional Study of Methanol Decomposition on Cu4 and Co4 Clusters

    SciTech Connect (OSTI)

    Mehmood, Faisal; Greeley, Jeffrey P.; Zapol, Peter; Curtiss, Larry A.

    2010-11-18

    A density functional theory study of the decomposition of methanol on Cu4 and Co4 clusters is presented. The reaction intermediates and activation barriers have been determined for reaction steps to form H2 and CO. For both clusters, methanol decomposition initiated by C-H and O-H bond breaking was investigated. In the case of a Cu4 cluster, methanol dehydrogenation through hydroxymethyl (CH2OH), hydroxymethylene (CHOH), formyl (CHO), and carbon monoxide (CO) is found to be slightly more favorable. For a Co4 cluster, the dehydrogenation pathway through methoxy (CH3O) and formaldehyde (CH2O) is slightly more favorable. Each of these pathways results in formation of CO and H2. The Co cluster pathway is very favorable thermodynamically and kinetically for dehydrogenation. However, since CO binds strongly, it is likely to poison methanol decomposition to H2 and CO at low temperatures. In contrast, for the Cu cluster, CO poisoning is not likely to be a problem since it does not bind strongly, but the dehydrogenation steps are not energetically favorable. Pathways involving C-O bond cleavage are even less energetically favorable. The results are compared to our previous study of methanol decomposition on Pd4 and Pd8 clusters. Finally, all reaction energy changes and transition state energies, including those for the Pd clusters, are related in a linear, Broensted-Evans-Polanyi plot.

  2. Crystal structure of 4-[benzylideneamino]-3-thiophen-2-yl-methyl-4,5-dihydro-1H-[1,2,4] triazole-5-one

    SciTech Connect (OSTI)

    Tanak, H.

    2013-12-15

    The crystal structure of the title compound C{sub 14}H{sub 12}N{sub 4}OS was determined by the X-ray diffraction method. The compound crystallizes in the triclinic space group P-bar1 with Z = 2. The molecule is not planar: the dihedral angle between the triazole and thiophene rings is 73.98(2)°, and that between the triazole and benzene rings is 4.05(2)°. The thiophene ring is disordered over two positions, which are approximately parallel and oppositely oriented. The major component refined to a site-occupancy factor of 0.573(3). An intramolecular C-H...O hydrogen bond generates an S(6) ring motif. In the crystal, molecules are linked together by two pairs of N-H...O interactions (to the same O atom as acceptor), forming inversion dimers. The crystal packing is also stabilized by π-π interactions [centroid-centroid distance is 3.978 Å].

  3. The one and a half monopoles solution of the SU(2) Yang–Mills–Higgs field theory

    SciTech Connect (OSTI)

    Teh, Rosy Ng, Ban-Loong; Wong, Khai-Ming

    2014-04-15

    Recently we have reported on the existence of finite energy SU(2) Yang–Mills–Higgs particle of one-half topological charge. In this paper, we show that this one-half monopole can co-exist with a ’t Hooft–Polyakov monopole. The magnetic charge of the one-half monopole is of opposite sign to the magnetic charge of the ’t Hooft–Polyakov monopole. However the net magnetic charge of the configuration is zero due to the presence of a semi-infinite Dirac string along the positive z-axis that carries the other half of the magnetic monopole charge. The solution possesses gauge potentials that are singular along the z-axis, elsewhere they are regular. The total energy is found to increase with the strength of the Higgs field self-coupling constant ?. However the dipole separation and the magnetic dipole moment decrease with ?. This solution is non-BPS even in the BPS limit when the Higgs self-coupling constant vanishes. -- Highlights: •This one-half monopole can co-exist with a ’t Hooft–Polyakov monopole. •The magnetic charge of the one-half monopole and one monopole is of opposite sign. •This solution is non-BPS. •The net magnetic charge of the configuration is zero. •This solution upon Cho decomposition is only singular along the negative z-axis.

  4. Oxygenates from light alkanes catalyzed by NO{sub x} in the gas phase

    SciTech Connect (OSTI)

    Otsuka, Kiyoshi; Takahashi, Ryo; Yamanaka, Ichiro

    1999-07-01

    The partial oxidations of light alkanes (methane, ethane, propane, and iso-butane) catalyzed by NO{sub x} in the gas phase have been studied at a pressure of less than 1 bar. For all the alkanes tested, the addition of NO to the mixture of alkanes and O{sub 2} enhanced the selectivities and the yields of oxygenates remarkably. It was suggested that NO{sub 2} generated from NO and O{sub 2} initiated the oxidation of alkanes and would specifically accelerate the C-C bond fission, enhancing the formation of C{sub 1}-oxygenates from ethane, propane, and iso-butane. No{sub 2} and NO would be used as a homogeneous catalyst at >600 C because nitroalkanes formed were decomposed completely, releasing the NO{sub x}. The comparison of the product distributions for the decomposition and oxidation of nitroalkanes and alkylnitrites strongly suggested that the oxygenates (HCHO, CH{sub 3}CHO, and CH{sub 3}COCH{sub 3}) were formed from the corresponding alkylnitrites which must be the reaction intermediates during the oxidation of alkanes with an O{sub 2} and NO mixture.

  5. Recent developments with the human repair genes ERCC2, ERCC4, and XRCC1

    SciTech Connect (OSTI)

    Thompson, L.H.; Caldecott, K.W.; Brookman, K.W.; Weber, C.A.; Salazar, E.S.; Takayama, K.; Fornace, A.J.

    1992-11-06

    ERCC2 was first identified as a gene on human chromosome 19 that complemented the UV sensitivity of CHO UV5 cells in somatic cell hybrids. Subsequent studies localized ERCC2 to the same chromosomal region (19q13.2--13.3) as the ERCC1 gene and showed that the two genes were less than 250 kb apart. Cloning of ERCC2 was accomplished by transfection of genomic DNA into UV5 cells and rescue of the gene from a secondary transformant. Recovery of the gene was aided by the presence of repetitive sequences that were detected on Southern blots with a probe for Alu-family repeats. ERCC2, which is 19 kb in size, quantitatively corrected the UV sensitivity and incision defect in UV5 cells upon transfection. An ERCC2 CDNA clone was recovered from the pcD2 expression library. Although this clone was truncated at the 5 in. end, it conferred transient, but not stable, correction to UV5 cells upon transfection. Based on genomic sequence, this clone was extended by oligonucleotide addition to obtain minigene constructs in which the complete open reading frame (ORF) was present. Translation of the ERCC2 ORF gives an amino acid sequence that has 72% similarity with the S. cerevisiae RAD3 protein, which encodes a DNA helicase.

  6. Cholesterol accumulation in Niemann Pick type C (NPC) model cells causes a shift in APP localization to lipid rafts

    SciTech Connect (OSTI)

    Kosicek, Marko; Malnar, Martina; Goate, Alison; Hecimovic, Silva

    2010-03-12

    It has been suggested that cholesterol may modulate amyloid-{beta} (A{beta}) formation, a causative factor of Alzheimer's disease (AD), by regulating distribution of the three key proteins in the pathogenesis of AD ({beta}-amyloid precursor protein (APP), {beta}-secretase (BACE1) and/or presenilin 1 (PS1)) within lipid rafts. In this work we tested whether cholesterol accumulation upon NPC1 dysfunction, which causes Niemann Pick type C disease (NPC), causes increased partitioning of APP into lipid rafts leading to increased CTF/A{beta} formation in these cholesterol-rich membrane microdomains. To test this we used CHO NPC1{sup -/-} cells (NPC cells) and parental CHOwt cells. By sucrose density gradient centrifugation we observed a shift in fl-APP/CTF compartmentalization into lipid raft fractions upon cholesterol accumulation in NPC vs. wt cells. Furthermore, {gamma}-secretase inhibitor treatment significantly increased fl-APP/CTF distribution in raft fractions in NPC vs. wt cells, suggesting that upon cholesterol accumulation in NPC1-null cells increased formation of APP-CTF and its increased processing towards A{beta} occurs in lipid rafts. Our results support that cholesterol overload, such as in NPC disease, leads to increased partitioning of APP/CTF into lipid rafts resulting in increased amyloidogenic processing of APP in these cholesterol-rich membranes. This work adds to the mechanism of the cholesterol-effect on APP processing and the pathogenesis of Alzheimer's disease and supports the role of lipid rafts in these processes.

  7. Adaptive nonlocal means filtering based on local noise level for CT denoising

    SciTech Connect (OSTI)

    Li, Zhoubo; Trzasko, Joshua D.; Lake, David S.; Blezek, Daniel J.; Manduca, Armando; Yu, Lifeng; Fletcher, Joel G.; McCollough, Cynthia H.

    2014-01-15

    Purpose: To develop and evaluate an image-domain noise reduction method based on a modified nonlocal means (NLM) algorithm that is adaptive to local noise level of CT images and to implement this method in a time frame consistent with clinical workflow. Methods: A computationally efficient technique for local noise estimation directly from CT images was developed. A forward projection, based on a 2D fan-beam approximation, was used to generate the projection data, with a noise model incorporating the effects of the bowtie filter and automatic exposure control. The noise propagation from projection data to images was analytically derived. The analytical noise map was validated using repeated scans of a phantom. A 3D NLM denoising algorithm was modified to adapt its denoising strength locally based on this noise map. The performance of this adaptive NLM filter was evaluated in phantom studies in terms of in-plane and cross-plane high-contrast spatial resolution, noise power spectrum (NPS), subjective low-contrast spatial resolution using the American College of Radiology (ACR) accreditation phantom, and objective low-contrast spatial resolution using a channelized Hotelling model observer (CHO). Graphical processing units (GPU) implementation of this noise map calculation and the adaptive NLM filtering were developed to meet demands of clinical workflow. Adaptive NLM was piloted on lower dose scans in clinical practice. Results: The local noise level estimation matches the noise distribution determined from multiple repetitive scans of a phantom, demonstrated by small variations in the ratio map between the analytical noise map and the one calculated from repeated scans. The phantom studies demonstrated that the adaptive NLM filter can reduce noise substantially without degrading the high-contrast spatial resolution, as illustrated by modulation transfer function and slice sensitivity profile results. The NPS results show that adaptive NLM denoising preserves the shape and peak frequency of the noise power spectrum better than commercial smoothing kernels, and indicate that the spatial resolution at low contrast levels is not significantly degraded. Both the subjective evaluation using the ACR phantom and the objective evaluation on a low-contrast detection task using a CHO model observer demonstrate an improvement on low-contrast performance. The GPU implementation can process and transfer 300 slice images within 5 min. On patient data, the adaptive NLM algorithm provides more effective denoising of CT data throughout a volume than standard NLM, and may allow significant lowering of radiation dose. After a two week pilot study of lower dose CT urography and CT enterography exams, both GI and GU radiology groups elected to proceed with permanent implementation of adaptive NLM in their GI and GU CT practices. Conclusions: This work describes and validates a computationally efficient technique for noise map estimation directly from CT images, and an adaptive NLM filtering based on this noise map, on phantom and patient data. Both the noise map calculation and the adaptive NLM filtering can be performed in times that allow integration with clinical workflow. The adaptive NLM algorithm provides effective denoising of CT data throughout a volume, and may allow significant lowering of radiation dose.

  8. An Exocyclic Methylene Group Acts As a Bioisostere of the 2′-Oxygen Atom in LNA

    SciTech Connect (OSTI)

    Seth, Punit P.; Allerson, Charles R.; Berdeja, Andres; Siwkowski, Andrew; Pallan, Pradeep S.; Gaus, Hans; Prakash, Thazha P.; Watt, Andrew T.; Egli, Martin; Swayze, Eric E.

    2010-12-07

    We show for the first time that it is possible to obtain LNA-like (Locked Nucleic Acid 1) binding affinity and biological activity with carbocyclic LNA (cLNA) analogs by replacing the 2{prime}-oxygen atom in LNA with an exocyclic methylene group. Synthesis of the methylene-cLNA nucleoside was accomplished by an intramolecular cyclization reaction between a radical at the 2{prime}-position and a propynyl group at the C-4{prime} position. Only methylene-cLNA modified oligonucleotides showed similar thermal stability and mismatch discrimination properties for complementary nucleic acids as LNA. In contrast, the close structurally related methyl-cLNA analogs showed diminished hybridization properties. Analysis of crystal structures of cLNA modified self-complementary DNA decamer duplexes revealed that the methylene group participates in a tight interaction with a 2{prime}-deoxyribose residue of the 5{prime}-terminal G of a neighboring duplex, resulting in the formation of a CH...O type hydrogen bond. This indicates that the methylene group retains a negative polarization at the edge of the minor groove in the absence of a hydrophilic 2{prime}-substituent and provides a rationale for the superior thermal stability of this modification. In animal experiments, methylene-cLNA antisense oligonucleotides (ASOs) showed similar in vivo activity but reduced toxicity as compared to LNA ASOs. Our work highlights the interchangeable role of oxygen and unsaturated moieties in nucleic acid structure and emphasizes greater use of this bioisostere to improve the properties of nucleic acids for therapeutic and diagnostic applications.

  9. A comparative density functional study of methanol decomposition on Cu{sub 4} and Co{sub 4} clusters.

    SciTech Connect (OSTI)

    Mehmood, F.; Greeley, J.; Zapol, P.; Curtiss, L. A.

    2010-08-12

    A density functional theory study of the decomposition of methanol on Cu{sub 4} and Co{sub 4} clusters is presented. The reaction intermediates and activation barriers have been determined for reaction steps to form H{sub 2} and CO. For both clusters, methanol decomposition initiated by C-H and O-H bond breaking was investigated. In the case of a Cu{sub 4} cluster, methanol dehydrogenation through hydroxymethyl (CH{sub 2}OH), hydroxymethylene (CHOH), formyl (CHO), and carbon monoxide (CO) is found to be slightly more favorable. For a Co{sub 4} cluster, the dehydrogenation pathway through methoxy (CH{sub 3}O) and formaldehyde (CH{sub 2}O) is slightly more favorable. Each of these pathways results in formation of CO and H{sub 2}. The Co cluster pathway is very favorable thermodynamically and kinetically for dehydrogenation. However, since CO binds strongly, it is likely to poison methanol decomposition to H{sub 2} and CO at low temperatures. In contrast, for the Cu cluster, CO poisoning is not likely to be a problem since it does not bind strongly, but the dehydrogenation steps are not energetically favorable. Pathways involving C-O bond cleavage are even less energetically favorable. The results are compared to our previous study of methanol decomposition on Pd{sub 4} and Pd{sub 8} clusters. Finally, all reaction energy changes and transition state energies, including those for the Pd clusters, are related in a linear, Broensted?Evans?Polanyi plot.

  10. Currently used pesticides and their mixtures affect the function of sex hormone receptors and aromatase enzyme activity

    SciTech Connect (OSTI)

    Kjeldsen, Lisbeth Stigaard; Ghisari, Mandana; Bonefeld-Jørgensen, Eva Cecilie, E-mail: ebj@mil.au.dk

    2013-10-15

    The endocrine-disrupting potential of pesticides is of health concern, since they are found ubiquitously in the environment and in food items. We investigated in vitro effects on estrogen receptor (ER) and androgen receptor (AR) transactivity, and aromatase enzyme activity, of the following pesticides: 2-methyl-4-chlorophenoxyacetic acid (MCPA), terbuthylazine, iodosulfuron-methyl-sodium, mesosulfuron-methyl, metsulfuron-methyl, chlormequat chloride, bitertanol, propiconazole, prothioconazole, mancozeb, cypermethrin, tau fluvalinate, malathion and the metabolite ethylene thiourea (ETU). The pesticides were analyzed alone and in selected mixtures. Effects of the pesticides on ER and AR function were assessed in human breast carcinoma MVLN cells and hamster ovary CHO-K1 cells, respectively, using luciferase reporter gene assays. Effects on aromatase enzyme activity were analyzed in human choriocarcinoma JEG-3 cells, employing the classical [{sup 3}H]{sub 2}O method. Five pesticides (terbuthylazine, propiconazole, prothioconazole, cypermethrin and malathion) weakly induced the ER transactivity, and three pesticides (bitertanol, propiconazole and mancozeb) antagonized the AR activity in a concentration-dependent manner. Three pesticides (terbuthylazine, propiconazole and prothioconazole) weakly induced the aromatase activity. In addition, two mixtures, consisting of three pesticides (bitertanol, propiconazole, cypermethrin) and five pesticides (terbuthylazine, bitertanol, propiconazole, cypermethrin, malathion), respectively, induced the ER transactivity and aromatase activity, and additively antagonized the AR transactivity. In conclusion, our data suggest that currently used pesticides possess endocrine-disrupting potential in vitro which can be mediated via ER, AR and aromatase activities. The observed mixture effects emphasize the importance of considering the combined action of pesticides in order to assure proper estimations of related health effect risks. - Highlights: • Currently used pesticides possess endocrine-disrupting (ED) potential in vitro. • ED effects can be mediated via sex hormone receptors and/or the aromatase enzyme. • Additive mixture effects on androgen receptor transactivity were observed.

  11. ELECTRON IRRADIATION OF KUIPER BELT SURFACE ICES: TERNARY N{sub 2}-CH{sub 4}-CO MIXTURES AS A CASE STUDY

    SciTech Connect (OSTI)

    Kim, Y. S.; Kaiser, R. I.

    2012-10-10

    The space weathering of icy Kuiper Belt Objects was investigated in this case study by exposing methane (CH{sub 4}) and carbon monoxide (CO) doped nitrogen (N{sub 2}) ices at 10 K to ionizing radiation in the form of energetic electrons. Online and in situ Fourier transform infrared spectroscopy was utilized to monitor the radiation-induced chemical processing of these ices. Along with isocyanic acid (HNCO), the products could be mainly derived from those formed in irradiated binary ices of the N{sub 2}-CH{sub 4} and CO-CH{sub 4} systems: nitrogen-bearing products were found in the form of hydrogen cyanide (HCN), hydrogen isocyanide (HNC), diazomethane (CH{sub 2}N{sub 2}), and its radical fragment (HCN{sub 2}); oxygen-bearing products were of acetaldehyde (CH{sub 3}CHO), formyl radical (HCO), and formaldehyde (H{sub 2}CO). As in the pure ices, the methyl radical (CH{sub 3}) and ethane (C{sub 2}H{sub 6}) were also detected, as were carbon dioxide (CO{sub 2}) and the azide radical (N{sub 3}). Based on the temporal evolution of the newly formed products, kinetic reaction schemes were then developed to fit the temporal profiles of the newly formed species, resulting in numerical sets of rate constants. The current study highlights important constraints on the preferential formation of isocyanic acid (HNCO) over hydrogen cyanide (HCN) and hydrogen isocyanide (HNC), thus guiding the astrobiological and chemical evolution of those distant bodies.

  12. Mesoporous Silica Nanomaterials for Applications in Catalysis, Sensing, Drug Delivery and Gene Transfection

    SciTech Connect (OSTI)

    Daniela Rodica Radu

    2005-12-19

    The central theme of this dissertation is represented by the versatility of mesoporous silica nanomaterials in various applications such as catalysis and bio-applications, with main focus on biological applications of Mesoporous Silica Nanospheres (MSN). The metamorphosis that we impose to these materials from catalysis to sensing and to drug and gene delivery is detailed in this dissertation. First, we developed a synthetic method that can fine tune the amount of chemically accessible organic functional groups on the pores surface of MSN by exploiting electrostatic and size matching between the cationic alkylammonium head group of the cetyltrimethylammonium bromide (CTAB) surfactant and various anionic organoalkoxysilane precursors at the micelle-water interface in a base-catalyzed condensation reaction of silicate. Aiming nature imitation, we demonstrated the catalytic abilities of the MSNs, We utilized an ethylenediamine functional group for chelating Cu{sup 2+} as a catalytic functional group anchored inside the mesopores. Thus, a polyalkynylene-based conducting polymer (molecular wire) was synthesized within the Cu-functionalized MSNs silica catalyst. For sensing applications, we have synthesized a poly(lactic acid) coated mesoporous silica nanosphere (PLA-MSN) material that serves as a fluorescence sensor system for detection of amino-containing neurotransmitters in neutral aqueous buffer. We exploited the mesoporosity of MSNs for encapsulating pharmaceutical drugs. We examined bio-friendly capping molecules such as polyamidoamine dendrimers of generations G2 to G4, to prevent the drug leaching. Next, the drug delivery system employed MSNs loaded with Doxorubicin, an anticancer drug. The results demonstrated that these nano-Trojan horses have ability to deliver Doxorubicin to cancer cells and induce their death. Finally, to demonstrate the potential of MSN as an universal cellular transmembrane nanovehicle, we anchored positively charged dendrimers on the surface of MSN and utilize them to complex cationic DNA. The p-EGFP-CI gene-coated MSN nanocomposite was able to transfect cancer cell lines, such as human HeLa and CHO cancer cell lines. The gene carrier ability of MSNs was further proved by transfecting primary cells and cotransfecting of two different genes in cancer cell lines. In sum, MSN are versatile partners in several types of applications.

  13. Anion Coordination in Metal-Organic Frameworks Functionalized with Urea Hydrogen-Bonding Groups

    SciTech Connect (OSTI)

    Custelcean, Radu; Moyer, Bruce A.; Bryantsev, Vyacheslav; Hay, Benjamin P.

    2005-12-15

    A series of metal-organic frameworks (MOFs) functionalized with urea hydrogen-bonding groups have been designed, synthesized, and structurally analyzed by single crystal X-ray diffraction to evaluate the efficacy of anion binding within the structural constraints of the MOFs. We found that urea-based functionalities may be used for anion binding within metal-organic frameworks when the tendency for urea???urea self-association is decreased by strengthening the intramolelcular CH???O hydrogen bonding of N-phenyl substituents to the carbonyl oxygen atom. Theoretical calculations indicate that N,N?-bis(m-pyridyl)urea (BPU) and N,N?-bis(m-cyanophenyl)urea (BCPU) should have enhanced hydrogen-bonding donor abilities toward anions and decreased tendencies to self-associate into hydrogen-bonded chains compared to other disubstituted ureas. Accordingly, BPU and BCPU were incorporated in MOFs as linkers through coordination of various Zn, Cu, and Ag transition metal salts, including Zn(ClO4)2, ZnSO4, Cu(NO3)2, Cu(CF3SO3)2, AgNO3 and AgSO3CH3. Structural analysis by single-crystal X-ray diffraction showed that these linkers are versatile anion binders, capable of chelate hydrogen bonding to all of the oxoanions explored. Anion binding by the urea functionalities was found to successfully compete with urea self-association in all cases except for that of charge-diffuse perchlorate. This research was sponsored by the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences of the U.S. Department of Energy, under contract number DE-AC05-00OR22725 with Oak Ridge National Laboratory (managed by UT-Battelle, LLC), and performed at Oak Ridge National laboratory and Pacific Northwest National Laboratory (managed by Battelle for the U.S. Department of Energy under contract DE-AC05-76RL01830). This research was performed in part using the Molecular Science Computing Facility (MSCF) in the William R. Wiley Environmental Molecular Sciences laboratory, a national scientific user facility sponsored by the U.S. Department of Energy's Office of Biological and Environmental Research located at the Pacific Northwest National Laboratory.

  14. FEEDSTOCK-FLEXIBLE REFORMER SYSTEM (FFRS) FOR SOLID OXIDE FUEL CELL (SOFC)- QUALITY SYNGAS

    SciTech Connect (OSTI)

    Kelly Jezierski; Andrew Tadd; Johannes Schwank; Roland Kibler; David McLean; Mahesh Samineni; Ryan Smith; Sameer Parvathikar; Joe Mayne; Tom Westrich; Jerry Mader; F. Michael Faubert

    2010-07-30

    The U.S. Department of Energy National Energy Technology Laboratory funded this research collaboration effort between NextEnergy and the University of Michigan, who successfully designed, built, and tested a reformer system, which produced highquality syngas for use in SOFC and other applications, and a novel reactor system, which allowed for facile illumination of photocatalysts. Carbon and raw biomass gasification, sulfur tolerance of non-Platinum Group Metals (PGM) based (Ni/CeZrO2) reforming catalysts, photocatalysis reactions based on TiO2, and mild pyrolysis of biomass in ionic liquids (ILs) were investigated at low and medium temperatures (primarily 450 to 850 C) in an attempt to retain some structural value of the starting biomass. Despite a wide range of processes and feedstock composition, a literature survey showed that, gasifier products had narrow variation in composition, a restriction used to develop operating schemes for syngas cleanup. Three distinct reaction conditions were investigated: equilibrium, autothermal reforming of hydrocarbons, and the addition of O2 and steam to match the final (C/H/O) composition. Initial results showed rapid and significant deactivation of Ni/CeZrO2 catalysts upon introduction of thiophene, but both stable and unstable performance in the presence of sulfur were obtained. The key linkage appeared to be the hydrodesulfurization activity of the Ni reforming catalysts. For feed stoichiometries where high H2 production was thermodynamically favored, stable, albeit lower, H2 and CO production were obtained; but lower thermodynamic H2 concentrations resulted in continued catalyst deactivation and eventual poisoning. High H2 levels resulted in thiophene converting to H2S and S surface desorption, leading to stable performance; low H2 levels resulted in unconverted S and loss in H2 and CO production, as well as loss in thiophene conversion. Bimetallic catalysts did not outperform Ni-only catalysts, and small Ni particles were found to have lower activities under S-free conditions, but did show less effect of S on performance, in this study. Imidazolium-based ILs, choline chloride compounds and low-melting eutectics of metal nitrates were evaluated, and it was found that, ILs have some capacity to dissolve cellulose and show thermal stability to temperatures where pyrolysis begins, have no vapor pressure, (simplifying product recoveries), and can dissolve ionic metal salts, allowing for the potential of catalytic reactions on breakdown intermediates. Clear evidence of photoactive commercial TiO2 was obtained, but in-house synthesis of photoactive TiO2 proved difficult, as did fixed-bed gasification, primarily due to the challenge of removing the condensable products from the reaction zone quickly enough to prevent additional reaction. Further investigation into additional non-PGM catalysts and ILs is recommended as a follow-up to this work.

  15. Bulk gold catalyzed oxidation reactions of amines and isocyanides and iron porphyrin catalyzed N-H and O-H bond insertion/cyclization reactions of diamines and aminoalcohols

    SciTech Connect (OSTI)

    Klobukowski, Erik

    2011-12-29

    This work involves two projects. The first project entails the study of bulk gold as a catalyst in oxidation reactions of isocyanides and amines. The main goal of this project was to study the activation and reactions of molecules at metal surfaces in order to assess how organometallic principles for homogeneous processes apply to heterogeneous catalysis. Since previous work had used oxygen as an oxidant in bulk gold catalyzed reactions, the generality of gold catalysis with other oxidants was examined. Amine N-oxides were chosen for study, due to their properties and use in the oxidation of carbonyl ligands in organometallic complexes. When amine N-oxides were used as an oxidant in the reaction of isocyanides with amines, the system was able to produce ureas from a variety of isocyanides, amines, and amine N-oxides. In addition, the rate was found to generally increase as the amine N-oxide concentration increased, and decrease with increased concentrations of the amine. Mechanistic studies revealed that the reaction likely involves transfer of an oxygen atom from the amine N-oxide to the adsorbed isocyanide to generate an isocyanate intermediate. Subsequent nucleophilic attack by the amine yields the urea. This is in contrast to the bulk gold-catalyzed reaction mechanism of isocyanides with amines and oxygen. Formation of urea in this case was proposed to proceed through a diaminocarbene intermediate. Moreover, formation of the proposed isocyanate intermediate is consistent with the reactions of metal carbonyl ligands, which are isoelectronic to isocyanides. Nucleophilic attack at coordinated CO by amine N-oxides produces CO{sub 2} and is analogous to the production of an isocyanate in this gold system. When the bulk gold-catalyzed oxidative dehydrogenation of amines was examined with amine N-oxides, the same products were afforded as when O{sub 2} was used as the oxidant. When the two types of oxidants were directly compared using the same reaction system and conditions, it was found that the oxidative dehydrogenation of dibenzylamine to Nbenzylidenebenzylamine, with N-methylmorpholine N-oxide (NMMO), was nearly quantitative (96%) within 24 h. However, the reaction with oxygen was much slower, with only a 52% yield of imine product over the same time period. Moreover, the rate of reaction was found to be influenced by the nature of the amine N-oxide. For example, the use of the weakly basic pyridine N-oxide (PyNO) led to an imine yield of only 6% after 24 h. A comparison of amine N-oxide and O2 was also examined in the oxidation of PhCH{sub 2}OH to PhCHO catalyzed by bulk gold. In this reaction, a 52% yield of the aldehyde was achieved when NMMO was used, while only a 7% product yield was afforded when O{sub 2} was the oxidant after 48 h. The bulk gold-catalyzed oxidative dehydrogenation of cyclic amines generates amidines, which upon treatment with Aerosil and water were found to undergo hydrolysis to produce lactams. Moreover, 5-, 6-, and 7-membered lactams could be prepared through a one-pot reaction of cyclic amines by treatment with oxygen, water, bulk gold, and Aerosil. This method is much more atom economical than industrial processes, does not require corrosive acids, and does not generate undesired byproducts. Additionally, the gold and Aerosil catalysts can be readily separated from the reaction mixture. The second project involved studying iron(III) tetraphenylporphyrin chloride, Fe(TPP)Cl, as a homogeneous catalyst for the generation of carbenes from diazo reagents and their reaction with heteroatom compounds. Fe(TPP)Cl, efficiently catalyzed the insertion of carbenes derived from methyl 2-phenyldiazoacetates into O-H bonds of aliphatic and aromatic alcohols. Fe(TPP)Cl was also found to be an effective catalyst for tandem N-H and O-H insertion/cyclization reactions when 1,2-diamines and 1,2-alcoholamines were treated with diazo reagents. This approach provides a one-pot process for synthesizing piperazinones and morpholinones and related analogues such as quinoxalinones and benzoxazin-2-ones.