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1

Structures for Three Membrane Transport Proteins Yield Functional Insights  

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

Structures for Three Membrane Structures for Three Membrane Transport Proteins Yield Functional Insights Structures for Three Membrane Transport Proteins Yield Functional Insights Print Wednesday, 27 January 2010 00:00 Cells depend on contact with their outside environment in order to thrive. Two examples illustrate why: In one, information needed to guide cellular processes is constantly transmitted across cell membranes by specialized proteins, and in the other, maintaining the right gradient of ions across the membrane is a process critical to the life and death of a cell. Membrane transport proteins-functioning either as channels or transporters-are the gatekeepers that control contact with the world outside the cell by catalyzing the flow of ions and molecules across cell membranes. Malfunctioning transport proteins can lead to cancer, inflammatory, and neurological diseases. Despite their importance in cell function and in a multitude of physiological processes such as sensing pain, there are still many unknowns about how they function. Recently, in an impressive series of three papers in Nature and Science, researchers at the Oregon Health and Science University delineated the structures of three transporter proteins, one of which had never before been characterized structurally in such detail. The structures were solved using ALS Beamlines 5.0.2, 8.2.1, and 8.2.2.

2

How the Membrane Protein AmtB Transports Ammonia  

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

How the Membrane Protein AmtB Transports Ammonia Print How the Membrane Protein AmtB Transports Ammonia Print Membrane proteins provide molecular-sized entry and exit portals for the various substances that pass into and out of cells. While life scientists have solved the structures of protein channels for ions, uncharged solutes, and even water, up to now they have only been able to guess at the precise mechanisms by which gases (such as NH3, CO2, O2, NO, N2O, etc.) cross biological membranes. But, with the first high-resolution structure of a bacterial ammonia transporter (AmtB), determined by a team in the Stroud group from the University of California, San Francisco, it is now known that this family of transporters conducts ammonia by stripping off the proton from the ammonium (NH4+) cation and conducting the uncharged NH3 "gas."

3

Aquaporins comprise a family of water-transporting membrane proteins. All aquaporins are efficient water transporters, while  

E-Print Network [OSTI]

are efficient water transporters, while sustaining strict selectivity, even against protons, thereby maintaining509 Aquaporins comprise a family of water-transporting membrane proteins. All aquaporins. Further insights, particularly with respect to the dynamics of water permeation and the filter mechanism

de Groot, Bert

4

How the Membrane Protein AmtB Transports Ammonia  

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

side of the membrane that recruits NH4+ and a narrower 20--long hydrophobic channel midway through the membrane that lowers the dissociation constant of NH4+, thereby forming...

5

Conformational Exchange in a Membrane Transport Protein Is Altered in Protein Crystals  

SciTech Connect (OSTI)

Successful macromolecular crystallography requires solution conditions that may alter the conformational sampling of a macromolecule. Here, site-directed spin labeling is used to examine a conformational equilibrium within BtuB, the Escherichia coli outer membrane transporter for vitamin B{sub 12}. Electron paramagnetic resonance (EPR) spectra from a spin label placed within the N-terminal energy coupling motif (Ton box) of BtuB indicate that this segment is in equilibrium between folded and unfolded forms. In bilayers, substrate binding shifts this equilibrium toward the unfolded form; however, EPR spectra from this same spin-labeled mutant indicate that this unfolding transition is blocked in protein crystals. Moreover, crystal structures of this spin-labeled mutant are consistent with the EPR result. When the free energy difference between substates is estimated from the EPR spectra, the crystal environment is found to alter this energy by 3 kcal/mol when compared to the bilayer state. Approximately half of this energy change is due to solutes or osmolytes in the crystallization buffer, and the remainder is contributed by the crystal lattice. These data provide a quantitative measure of how a conformational equilibrium in BtuB is modified in the crystal environment, and suggest that more-compact, less-hydrated substates will be favored in protein crystals.

D Freed; P Horanyi; M Wiener; D Cafiso

2011-12-31T23:59:59.000Z

6

Conformational Exchange in a Membrane Transport Protein Is Altered in Protein Crystals  

SciTech Connect (OSTI)

Successful macromolecular crystallography requires solution conditions that may alter the conformational sampling of a macromolecule. Here, site-directed spin labeling is used to examine a conformational equilibrium within BtuB, the Escherichia coli outer membrane transporter for vitamin B{sub 12}. Electron paramagnetic resonance (EPR) spectra from a spin label placed within the N-terminal energy coupling motif (Ton box) of BtuB indicate that this segment is in equilibrium between folded and unfolded forms. In bilayers, substrate binding shifts this equilibrium toward the unfolded form; however, EPR spectra from this same spin-labeled mutant indicate that this unfolding transition is blocked in protein crystals. Moreover, crystal structures of this spin-labeled mutant are consistent with the EPR result. When the free energy difference between substates is estimated from the EPR spectra, the crystal environment is found to alter this energy by 3 kcal/mol when compared to the bilayer state. Approximately half of this energy change is due to solutes or osmolytes in the crystallization buffer, and the remainder is contributed by the crystal lattice. These data provide a quantitative measure of how a conformational equilibrium in BtuB is modified in the crystal environment, and suggest that more-compact, less-hydrated substates will be favored in protein crystals.

Freed, Daniel M.; Horanyi, Peter S.; Wiener, Michael C.; Cafiso, David S. (UV)

2010-09-27T23:59:59.000Z

7

Protein Flips Lipids Across Membranes  

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

Protein Flips Lipids Across Protein Flips Lipids Across Membranes Protein Flips Lipids Across Membranes Print Wednesday, 26 October 2005 00:00 Found ubiquitously in both bacteria and humans, membrane proteins of the adenosine triphosphate (ATP)-binding cassette (ABC) transporter family have been implicated in both antibiotic and cancer-drug resistance. The mechanisms used by these proteins to expel toxins from cells therefore represent key targets for the development of drugs designed to combat the growing problem of multidrug resistance. Toward this end, researchers from The Scripps Research Institute have succeeded in crystallizing MsbA-an ABC transporter protein-together with a substrate (the molecule to be transported) and a hydrolyzed (spent) form of the nucleotide ATP, the transporter's source of chemical energy. The resulting molecular complex is caught at a moment following the transporter's "power stroke," the force-generating part of the transport cycle. This snapshot suggests a mechanism by which the substrate molecule gets flipped head-over-tail from one side of the membrane to the other, on its way out of the cell.

8

Protein Flips Lipids Across Membranes  

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

Protein Flips Lipids Across Membranes Print Protein Flips Lipids Across Membranes Print Found ubiquitously in both bacteria and humans, membrane proteins of the adenosine triphosphate (ATP)-binding cassette (ABC) transporter family have been implicated in both antibiotic and cancer-drug resistance. The mechanisms used by these proteins to expel toxins from cells therefore represent key targets for the development of drugs designed to combat the growing problem of multidrug resistance. Toward this end, researchers from The Scripps Research Institute have succeeded in crystallizing MsbA-an ABC transporter protein-together with a substrate (the molecule to be transported) and a hydrolyzed (spent) form of the nucleotide ATP, the transporter's source of chemical energy. The resulting molecular complex is caught at a moment following the transporter's "power stroke," the force-generating part of the transport cycle. This snapshot suggests a mechanism by which the substrate molecule gets flipped head-over-tail from one side of the membrane to the other, on its way out of the cell.

9

Protein Flips Lipids Across Membranes  

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

Protein Flips Lipids Across Membranes Print Protein Flips Lipids Across Membranes Print Found ubiquitously in both bacteria and humans, membrane proteins of the adenosine triphosphate (ATP)-binding cassette (ABC) transporter family have been implicated in both antibiotic and cancer-drug resistance. The mechanisms used by these proteins to expel toxins from cells therefore represent key targets for the development of drugs designed to combat the growing problem of multidrug resistance. Toward this end, researchers from The Scripps Research Institute have succeeded in crystallizing MsbA-an ABC transporter protein-together with a substrate (the molecule to be transported) and a hydrolyzed (spent) form of the nucleotide ATP, the transporter's source of chemical energy. The resulting molecular complex is caught at a moment following the transporter's "power stroke," the force-generating part of the transport cycle. This snapshot suggests a mechanism by which the substrate molecule gets flipped head-over-tail from one side of the membrane to the other, on its way out of the cell.

10

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

This report covers the following tasks: Task 1--Design, fabricate and evaluate ceramic to metal seals based on graded ceramic powder/metal braze joints; Task 2--Evaluate the effect of defect configuration on ceramic membrane conductivity and long term chemical and structural stability; Task 3--Determine materials mechanical properties under conditions of high temperatures and reactive atmospheres; Task 4--Evaluate phase stability and thermal expansion of candidate perovskite membranes and develop techniques to support these materials on porous metal structures; Task 5--Assess the microstructure of membrane materials to evaluate the effects of vacancy-impurity association, defect clusters, and vacancy-dopant association on the membrane performance and stability; and Task 6--Measure kinetics of oxygen uptake and transport in ceramic membrane materials under commercially relevant conditions using isotope labeling techniques.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2002-04-01T23:59:59.000Z

11

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

This is the third quarterly report on oxygen Transport Ceramic Membranes. In the following, the report describes the progress made by our university partners in Tasks 1 through 6, experimental apparatus that was designed and built for various tasks of this project, thermodynamic calculations, where applicable and work planned for the future. (Task 1) Design, fabricate and evaluate ceramic to metal seals based on graded ceramic powder/metal braze joints. (Task 2) Evaluate the effect of defect configuration on ceramic membrane conductivity and long term chemical and structural stability. (Task 3) Determine materials mechanical properties under conditions of high temperatures and reactive atmospheres. (Task 4) Evaluate phase stability and thermal expansion of candidate perovskite membranes and develop techniques to support these materials on porous metal structures. (Task 5) Assess the microstructure of membrane materials to evaluate the effects of vacancy-impurity association, defect clusters, and vacancy-dopant association on the membrane performance and stability. (Task 6) Measure kinetics of oxygen uptake and transport in ceramic membrane materials under commercially relevant conditions using isotope labeling techniques.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2000-10-01T23:59:59.000Z

12

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

In the present quarter, oxygen transport perovskite ceramic membranes are evaluated for strength and fracture in oxygen gradient conditions. Oxygen gradients are created in tubular membranes by insulating the inner surface from the reducing environment by platinum foils. Fracture in these test conditions is observed to have a gradient in trans and inter-granular fracture as opposed to pure trans-granular fracture observed in homogeneous conditions. Fracture gradients are reasoned to be due to oxygen gradient set up in the membrane, variation in stoichiometry across the thickness and due to varying decomposition of the parent perovskite. The studies are useful in predicting fracture criterion in actual reactor conditions and in understanding the initial evolution of fracture processes.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2002-07-01T23:59:59.000Z

13

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

In the present quarter, the possibility of using a more complex interfacial engineering approach to the development of reliable and stable oxygen transport perovskite ceramic membranes/metal seals is discussed. Experiments are presented and ceramic/metal interactions are characterized. Crack growth and fracture toughness of the membrane in the reducing conditions are also discussed. Future work regarding this approach is proposed are evaluated for strength and fracture in oxygen gradient conditions. Oxygen gradients are created in tubular membranes by insulating the inner surface from the reducing environment by platinum foils. Fracture in these test conditions is observed to have a gradient in trans and inter-granular fracture as opposed to pure trans-granular fracture observed in homogeneous conditions. Fracture gradients are reasoned to be due to oxygen gradient set up in the membrane, variation in stoichiometry across the thickness and due to varying decomposition of the parent perovskite. The studies are useful in predicting fracture criterion in actual reactor conditions and in understanding the initial evolution of fracture processes.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2003-01-01T23:59:59.000Z

14

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

In the present quarter, experiments are presented on ceramic/metal interactions of Zirconia/Ni-B-Si system and with a thin Ti coating deposited on zirconia surface. Processing of perovskites of LSC, LSF and LSCF composition for evaluation of mechanical properties as a function of environment are begun. The studies are to be in parallel with LSFCO composition to characterize the segregation of cations and slow crack growth in environmental conditions. La{sub 1-x}Sr{sub x}FeO{sub 3-d} has also been characterized for paramagnetic ordering at room temperature and the evolution of magnetic moments as a function of temperature are investigated. Investigation on the thermodynamic properties of the membrane materials are continued to develop a complete model for the membrane transport.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2003-01-01T23:59:59.000Z

15

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

Conversion of natural gas to liquid fuels and chemicals is a major goal for the Nation as it enters the 21st Century. Technically robust and economically viable processes are needed to capture the value of the vast reserves of natural gas on Alaska's North Slope, and wean the Nation from dependence on foreign petroleum sources. Technologies that are emerging to fulfill this need are all based syngas as an intermediate. Syngas (a mixture of hydrogen and carbon monoxide) is a fundamental building block from which chemicals and fuels can be derived. Lower cost syngas translates directly into more cost-competitive fuels and chemicals. The currently practiced commercial technology for making syngas is either steam methane reforming (SMR) or a two-step process involving cryogenic oxygen separation followed by natural gas partial oxidation (POX). These high-energy, capital-intensive processes do not always produce syngas at a cost that makes its derivatives competitive with current petroleum-based fuels and chemicals. This project has the following 6 main tasks: Task 1--Design, fabricate and evaluate ceramic to metal seals based on graded ceramic powder/metal braze joints. Task 2--Evaluate the effect of defect configuration on ceramic membrane conductivity and long term chemical and structural stability. Task 3--Determine materials mechanical properties under conditions of high temperatures and reactive atmospheres. Task 4--Evaluate phase stability and thermal expansion of candidate perovskite membranes and develop techniques to support these materials on porous metal structures. Task 5--Assess the microstructure of membrane materials to evaluate the effects of vacancy-impurity association, defect clusters, and vacancy-dopant association on the membrane performance and stability. Task 6--Measure kinetics of oxygen uptake and transport in ceramic membrane materials under commercially relevant conditions using isotope labeling techniques.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2001-12-01T23:59:59.000Z

16

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. Thermogravimetric analysis (TGA) was carried out on La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} to investigate oxygen deficiency ({delta}) of the sample. The TGA was performed in a controlled atmosphere using oxygen, argon, carbon monoxide and carbon dioxide with adjustable gas flow rates. In this experiment, the weight loss and gain of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} was directly measured by TGA. The weight change of the sample was evaluated at between 600 and 1250 C in air or 1000 C as a function of oxygen partial pressure. The oxygen deficiencies calculated from TGA data as a function of oxygen activity and temperature will be estimated and compared with that from neutron diffraction measurement in air. The LSFT and LSFT/CGO membranes were fabricated from the powder obtained from Praxair Specialty Ceramics. The sintered membranes were subjected to microstructure analysis and hardness analysis. The LSFT membrane is composed of fine grains with two kinds of grain morphology. The grain size distribution was characterized using image analysis. In LSFT/CGO membrane a lot of grain pullout was observed from the less dense, porous phase. The hardness of the LSFT and dual phase membranes were studied at various loads. The hardness values obtained from the cross section of the membranes were also compared to that of the values obtained from the surface. An electrochemical cell has been designed and built for measurements of the Seebeck coefficient as a function of temperature and pressure. Measurements on La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} as a function of temperature an oxygen partial pressure are reported. Further analysis of the dilatometry data obtained previously is presented. A series of isotope transients under air separation mode (small gradient) were completed on the membrane of LSCrF-2828 at 900 C. Low pO{sub 2} atmospheres based on with CO-CO{sub 2} mixtures have also been admitted to the delivery side of the LSCrF-2828 membrane to produce the gradients which exist under syngas generation conditions. The CO-CO{sub 2} mixtures have normal isotopic {sup 18}O abundances. The evolution of {sup 18}O on the delivery side in these experiments after an {sup 18}O pulse on the air side reveals a wealth of information about the oxygen transport processes.

S. Bandopadhyay; N. Nagabhushana; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

2005-02-01T23:59:59.000Z

17

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

The present quarterly report describes some of the initial studies on newer compositions and also includes newer approaches to address various materials issues such as in metal-ceramic sealing. The current quarter's research has also focused on developing a comprehensive reliability model for predicting the structural behavior of the membranes in realistic conditions. In parallel to industry provided compositions, models membranes have been evaluated in varying environment. Of importance is the behavior of flaws and generation of new flaws aiding in fracture. Fracture mechanics parameters such as crack tip stresses are generated to characterize the influence of environment. Room temperature slow crack growth studies have also been initiated in industry provided compositions. The electrical conductivity and defect chemistry of an A site deficient compound (La{sub 0.55}Sr{sub 0.35}FeO{sub 3}) was studied. A higher conductivity was observed for La{sub 0.55}Sr{sub 0.35}FeO{sub 3} than that of La{sub 0.60}Sr{sub 0.40}FeO{sub 3} and La{sub 0.80}Sr{sub 0.20}FeO{sub 3}. Defect chemistry analysis showed that it was primarily contributed by a higher carrier concentration in La{sub 0.55}Sr{sub 0.35}FeO{sub 3}. Moreover, the ability for oxygen vacancy generation is much higher in La{sub 0.55}Sr{sub 0.35}FeO{sub 3} as well, which indicates a lower bonding strength between Fe-O and a possible higher catalytic activity for La{sub 0.55}Sr{sub 0.35}FeO{sub 3}. The program continued to investigate the thermodynamic properties (stability and phase separation behavior) and total conductivity of prototype membrane materials. The data are needed together with the kinetic information to develop a complete model for the membrane transport. Previous report listed initial measurements on a sample of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-x} prepared in-house by Praxair. Subsequently, a second sample of powder from a larger batch of sample were characterized and compared with the results from the previous batch.

S. Bandopadhyay; N. Nagabhushana; Thomas W. Eagar; Harold R. Larson; Raymundo Arroyave; X.-D Zhou; Y.-W. Shin; H.U. Anderson; Nigel Browning; Alan Jacobson; C.A. Mims

2003-11-01T23:59:59.000Z

18

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In this report, in situ neutron diffraction was used to characterize the chemical and structural properties of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} (here after as L2SF55T) specimen, which was subject to measurements of neutron diffraction from room temperature to 900 C. It was found that space group of R3c yielded a better refinement than a cubic structure of Pm3m. Oxygen occupancy was nearly 3 in the region from room temperature to 700 C, above which the occupancy decreased due to oxygen loss. Dense OTM bars provided by Praxair were loaded to fracture at varying stress rates. Studies were done at room temperature in air and at 1000 C in a specified environment to evaluate slow crack growth behavior. The X-Ray data and fracture mechanisms points to non-equilibrium decomposition of the LSFCO OTM membrane. The non-equilibrium conditions could probably be due to the nature of the applied stress field (stressing rates) and leads to transition in crystal structures and increased kinetics of decomposition. The formations of a Brownmillerite or Sr2Fe2O5 type structures, which are orthorhombic are attributed to the ordering of oxygen vacancies. The cubic to orthorhombic transitions leads to 2.6% increase in strains and thus residual stresses generated could influence the fracture behavior of the OTM membrane. Continued investigations on the thermodynamic properties (stability and phase-separation behavior) and total conductivity of prototype membrane materials were carried out. The data are needed together with the kinetic information to develop a complete model for the membrane transport. Previously characterization, stoichiometry and conductivity measurements for samples of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} were reported. In this report, measurements of the chemical and thermal expansion as a function of temperature and p{sub O2} are described.

S. Bandopadhyay; N. Nagabhushana; X.-D Zhou; Q. Cai; J. Yang; W.B. Yelon; W.J. James; H.U. Anderson; Alan Jacobson; C.A. Mims

2004-05-01T23:59:59.000Z

19

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

In the present quarter, experiments are presented on ceramic/metal interactions of Zirconia/ Ni-B-Si system and with a thin Ti coating deposited on zirconia surface. Existing facilities were modified for evaluation of environmental assisted slow crack growth and creep in flexural mode. Processing of perovskites of LSC, LSF and LSCF composition were continued for evaluation of mechanical properties as a function of environment. These studies in parallel to those on the LSFCO composition is expect to yield important information on questions such as the role of cation segregation and the stability of the perovskite structure on crack initiation vs. crack growth. Studies have been continued on the La{sub 1-x}Sr{sub x}FeO{sub 3-d} composition using neutron diffraction and TGA studies. A transition from p-type to n-type of conductor was observed at relative low pO{sub 2}, at which the majority carriers changed from the holes to electrons because of the valence state decreases in Fe due to the further loss of oxygen. Investigation on the thermodynamic properties of the membrane materials are continued to develop a complete model for the membrane transport. Data obtained at 850 C show that the stoichiometry in La{sub 0.2}Sr{sub 0.8}Fe{sub 0.8}Cr{sub 0.2}O{sub 3-x} vary from {approx}2.85 to 2.6 over the pressure range studied. From the stoichiometry a lower limit of 2.6 corresponding to the reduction of all Fe{sup 4+} to Fe{sup 3+} and no reduction of Cr{sup 3+} is expected.

S. Bandopadhyay; N. Nagabhushana

2003-08-07T23:59:59.000Z

20

Oxygen Transport Membranes  

SciTech Connect (OSTI)

The focus of this research was to develop new membrane materials by synthesizing different compounds and determining their defect structures, crystallographic structures and electrical properties. In addition to measuring electrical conductivity, oxygen vacancy concentration was also evaluated using thermogravimetry, Neutron diffraction and Moessbauer Spectroscopy. The reducing conditions (CO{sub 2}/CO/H{sub 2} gas mixtures with steam) as encountered in a reactor environment can be expected to have significant influence on the mechanical properties of the oxides membranes. Various La based materials with and without Ti were selected as candidate membrane materials for OTM. The maximum electrical conductivity of LSF in air as a function of temperature was achieved at < 600 C and depends on the concentration of Sr (acceptor dopant). Oxygen occupancy in LSF was estimated using Neutron diffractometry and Moessbauer Spectroscopy by measuring magnetic moment changes depending on the Fe{sup 3+} and Fe{sup 4+} ratio. After extensive studies of candidate materials, lanthanum ferrites (LSF and LSFT) were selected as the favored materials for the oxygen transport membrane (OTM). LSF is a very good material for an OTM because of its high electronic and oxygen ionic conductivity if long term stability and mechanical strength are improved. LSFT not only exhibits p-type behavior in the high oxygen activity regime, but also has n-type conduction in reducing atmospheres. Higher concentrations of oxygen vacancies in the low oxygen activity regime may improve the performance of LSFT as an OTM. The hole concentration is related to the difference in the acceptor and donor concentration by the relation p = [Sr'{sub La}]-[Ti{sm_bullet}{sub Fe}]. The chemical formulation predicts that the hole concentration is, p = 0.8-0.45 or 0.35. Experimental measurements indicated that p is about {approx} 0.35. The activation energy of conduction is 0.2 eV which implies that LSCF conducts via the small polaron conduction mechanism. Scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) were used to develop strategies to detect and characterize vacancy creation, dopant segregations and defect association in the oxygen conducting membrane material. The pO{sub 2} and temperature dependence of the conductivity, non-stoichiometry and thermal-expansion behavior of compositions with increasing complexity of substitution on the perovskite A and B sites were studied. Studies with the perovskite structure show anomalous behavior at low oxygen partial pressures (<10{sup -5} atm). The anomalies are due to non-equilibrium effects and can be avoided by using very strict criteria for the attainment of equilibrium. The slowness of the oxygen equilibration kinetics arises from two different mechanisms. In the first, a two phase region occurs between an oxygen vacancy ordered phase such as brownmillerite SrFeO{sub 2.5} and perovskite SrFeO{sub 3-x}. The slow kinetics is associated with crossing the two phase region. The width of the miscibility gap decreases with increasing temperature and consequently the effect is less pronounced at higher temperature. The preferred kinetic pathway to reduction of perovskite ferrites when the vacancy concentration corresponds to the formation of significant concentrations of Fe{sup 2+} is via the formation of a Ruddlesden-Popper (RP) phases as clearly observed in the case of La{sub 0.5}Sr{sub 0.5}FeO{sub 3-x} where LaSrFeO{sub 4} is found together with Fe. In more complex compositions, such as LSFTO, iron or iron rich phases are observed locally with no evidence for the presence of discrete RP phase. Fracture strength of tubular perovskite membranes was determined in air and in reducing atmospheric conditions. The strength of the membrane decreased with temperature and severity of reducing conditions although the strength distribution (Weibull parameter, m) was relatively unaltered. Surface and volume dominated the fracture origins and the overall fracture was purely transgranular. The dual phas

S. Bandopadhyay

2008-08-30T23:59:59.000Z

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


21

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In this report, Moessbauer spectroscopy was used to study the local environmentals of LSFT with various level of oxygen deficiency. Ionic valence state, magnetic interaction and influence of Ti on superexchange are discussed Stable crack growth studies on Dense OTM bars provided by Praxair were done at elevated temperature, pressure and elevated conditions. Post-fracture X-ray data of the OTM fractured at 1000 C in environment were refined by FullProf code and results indicate a distortion of the parent cubic perovskite to orthorhombic structure with reduced symmetry. TGA-DTA studies on the post-fracture samples also indicated residual effect arising from the thermal and stress history of the samples. An electrochemical cell has been designed and built for measurements of the Seebeck coefficient as a function of temperature and pressure. The initial measurements on La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} are reported. Neutron diffraction measurements of the same composition are in agreement with both the stoichiometry and the kinetic behavior observed in coulometric titration measurements. A series of isotope transients under air separation mode (small gradient) were completed on the membrane of LSCrF-2828 at 900 C. Low pO{sub 2} atmospheres based on with CO-CO{sub 2} mixtures have also been admitted to the delivery side of the LSCrF-2828 membrane to produce the gradients which exist under syngas generation conditions. The COCO{sub 2} mixtures have normal isotopic {sup 18}O abundances. The evolution of {sup 18}O on the delivery side in these experiments after an {sup 18}O pulse on the air side reveals a wealth of information about the oxygen transport processes.

S. Bandopadhyay; N. Nagabhushana; X.-D Zhou; Q. Cai; J. Yang; W.B. Yelon; W.J. James; H.U. Anderson; Alan Jacobson; C.A. Mims

2004-10-01T23:59:59.000Z

22

Energy use by biological protein transport pathways  

E-Print Network [OSTI]

residing within energy-conserving membranes use transmembrane ion gradients to drive substrate transport receptors impart specificity to a targeting route, and transport across or into the membrane is typicallyEnergy use by biological protein transport pathways Nathan N. Alder1 and Steven M. Theg2 1

Economou, Tassos

23

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In this report, in situ neutron diffraction was used to characterize the chemical and structural properties of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} (here after as L2SF55T) specimen, which was subject to measurements of neutron diffraction from room temperature to 900 C in N{sub 2}. Space group of R3c was found to result in a better refinement and is used in this study. The difference for crystal structure, lattice parameters and local crystal chemistry for LSFT nearly unchanged when gas environment switched from air to N{sub 2}. Stable crack growth studies on Dense OTM bars provided by Praxair were done at room temperature in air. A bridge-compression fixture was fabricated to achieve stable pre-cracks from Vickers indents. Post fracture evaluation indicated stable crack growth from the indent and a regime of fast fracture. Post-fracture X-ray data of the OTM fractured at 1000 C in environment were refined by FullProf code and results indicate a distortion of the parent cubic perovskite to orthorhombic structure with reduced symmetry. TGA-DTA studies on the post-fracture samples also indicated residual effect arising from the thermal and stress history of the samples. The thermal and chemical expansion of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} were studied at 800 {le} T {le} 1000 C and at {approx} 1 x 10{sup -15} {le} pO{sub 2} {le} 0.21 atm. The thermal expansion coefficient of the sample was calculated from the dilatometric analysis in the temperature range between room temperature and 1200 C in air. A series of isotope transients under air separation mode (small gradient) were completed on the membrane of LSCrF-2828 at 900 C. Low pO{sub 2} atmospheres based on with CO-CO{sub 2} mixtures have also been admitted to the delivery side of the LSCrF-2828 membrane to produce the gradients which exist under syngas generation conditions. The CO-CO{sub 2} mixtures have normal isotopic {sup 18}O abundances. The evolution of {sup 18}O on the delivery side in these experiments after an {sup 18}O pulse on the air side reveals a wealth of information about the oxygen transport processes.

S. Bandopadhyay; N. Nagabhushana; X.-D Zhou; Q. Cai; J. Yang; W.B. Yelon; W.J. James; H.U. Anderson; Alan Jacobson; C.A. Mims

2004-05-01T23:59:59.000Z

24

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In the current research, the electrical conductivity and Seebeck coefficient were measured as a function of temperature in air. Based on these measurements, the charge carrier concentration, net acceptor dopant concentration, activation energy of conduction and mobility were estimated. The studies on the fracture toughness of the LSFT and dual phase membranes at room temperature have been completed and reported previously. The membranes that are exposed to high temperatures at an inert and a reactive atmosphere undergo many structural and chemical changes which affects the mechanical properties. To study the effect of temperature on the membranes when exposed to an inert environment, the membranes (LAFT and Dual phase) were heat treated at 1000 C in air and N{sub 2} atmosphere and hardness and fracture toughness of the membranes were studied after the treatment. The indentation method was used to find the fracture toughness and the effect of the heat treatment on the mechanical properties of the membranes. Further results on the investigation of the origin of the slow kinetics on reduction of ferrites have been obtained. The slow kinetics appears to be related to a non-equilibrium reduction pathway that initially results in the formation of iron particles. At long times, equilibrium can be reestablished with recovery of the perovskite phase. 2-D modeling of oxygen movement has been undertaken in order to fit isotope data. The model will serve to study ''frozen'' profiles in patterned or composite membranes.

S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

2005-11-01T23:59:59.000Z

25

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

In this quarter a systematic analysis on the decomposition behavior of the OTM membranes at air and nitrogen were initiated to understand the structural and stoichiometric changes associated with elevated temperatures. Evaluation of the flexural strengths using 4-point bend test was also started for the dual phase membranes. Initial results on the synthesis of dual phase composite materials have been obtained. The measurements have focused on the compatibility of mixed conductors with the pure ionic conductors yttria stabilized zirconia (YSZ) and gadolinium doped ceria (GDC). The initial results obtained for three different mixed conductors suggest that (GDC) is the better choice. A new membrane permeation system has been designed and tested and sintering studies of biphasic systems are in progress.

S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

2006-05-01T23:59:59.000Z

26

Composite oxygen transport membrane  

DOE Patents [OSTI]

A method of producing a composite oxygen ion membrane and a composite oxygen ion membrane in which a porous fuel oxidation layer and a dense separation layer and optionally, a porous surface exchange layer are formed on a porous support from mixtures of (Ln.sub.1-xA.sub.x).sub.wCr.sub.1-yB.sub.yO.sub.3-.delta. and a doped zirconia. In the porous fuel oxidation layer and the optional porous surface exchange layer, A is Calcium and in the dense separation layer A is not Calcium and, preferably is Strontium. Preferred materials are (La.sub.0.8Ca.sub.0.2).sub.0.95Cr.sub.0.5Mn.sub.0.5O.sub.3-.delta. for the porous fuel oxidation and optional porous surface exchange layers and (La.sub.0.8Sr.sub.0.2).sub.0.95Cr.sub.0.5Fe.sub.0.5O.sub.3-.delta. for the dense separation layer. The use of such materials allows the membrane to sintered in air and without the use of pore formers to reduce membrane manufacturing costs. The use of materials, as described herein, for forming the porous layers have application for forming any type of porous structure, such as a catalyst support.

Christie, Gervase Maxwell; Lane, Jonathan A.

2014-08-05T23:59:59.000Z

27

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

This is the fifth quarterly report on a new study to develop a ceramic membrane/metal joint. Results of wetting experiments on commercially available Nickel based brazing alloys on perovskite surfaces are described. Additionally, experimental and numerical investigations on the strength of concentric ceramic/metal joints are presented.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2001-02-01T23:59:59.000Z

28

Ion transport through cell membrane channels  

E-Print Network [OSTI]

We discuss various models of ion transport through cell membrane channels. Recent experimental data shows that sizes of ion channels are compared to those of ions and that only few ions may be simultaneously in any single channel. Theoretical description of ion transport in such channels should therefore take into account interactions between ions and between ions and channel proteins. This is not satisfied by macroscopic continuum models based on Poisson-Nernst-Planck equations. More realistic descriptions of ion transport are offered by microscopic Brownian and molecular dynamics. One should also take into account a dynamical character of the channel structure. This is not yet addressed in the literature

Jan Gomulkiewicz; Jacek Miekisz; Stanislaw Miekisz

2007-06-05T23:59:59.000Z

29

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

This is the fourth quarterly report on a new study to develop a ceramic membrane/metal joint. The first experiments using the La-Sr-Fe-O ceramic are reported. Some of the analysis performed on the samples obtained are commented upon. A set of experiments to characterize the mechanical strength and thermal fatigue properties of the joints has been designed and begun. Finite element models of joints used to model residual stresses are described.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2000-07-01T23:59:59.000Z

30

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In the previous research, the reference point of oxygen occupancy was determined and verified. In the current research, the oxygen occupancy was investigated at 1200 C as a function of oxygen activity and compared with that at 1000 C. The cause of bumps at about 200 C was also investigated by using different heating and cooling rates during TGA. The fracture toughness of LSFT and dual phase membranes at room temperature is an important mechanical property. Vicker's indentation method was used to evaluate this toughness. Through this technique, a K{sub Ic} (Mode-I Fracture Toughness) value is attained by means of semi-empirical correlations between the indentation load and the length of the cracks emanating from the corresponding Vickers indentation impression. In the present investigation, crack propagation behavior was extensively analyzed in order to understand the strengthening mechanisms involved in the non-transforming La based ceramic composites. Cracks were generated using Vicker's indenter and used to identify and evaluate the toughening mechanisms involved. Preliminary results of an electron microscopy study of the origin of the slow kinetics on reduction of ferrites have been obtained. The slow kinetics appear to be related to a non-equilibrium reduction pathway that initially results in the formation of iron particles. At long times, equilibrium can be reestablished with recovery of the perovskite phase. Modeling of the isotopic transients on operating membranes (LSCrF-2828 at 900 C) and a ''frozen'' isotope profile have been analyzed in conjunction with a 1-D model to reveal the gradient in oxygen diffusivity through the membrane under conditions of high chemical gradients.

S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

2005-08-01T23:59:59.000Z

31

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. The in situ electrical conductivity and Seebeck coefficient measurements were made on LSFT at 1000 and 1200 C over the oxygen activity range from air to 10{sup -15} atm. The electrical conductivity measurements exhibited a p to n type transition at an oxygen activity of 1 x 10{sup -10} at 1000 C and 1 x 10{sup -6} at 1200 C. Thermogravimetric studies were also carried out over the same oxygen activities and temperatures. Based on the results of these measurements, the chemical and mechanical stability range of LSFT were determined and defect structure was established. The studies on the fracture toughness of the LSFT and dual phase membranes exposed to air and N{sub 2} at 1000 C was done and the XRD and SEM analysis of the specimens were carried out to understand the structural and microstructural changes. The membranes that are exposed to high temperatures at an inert and a reactive atmosphere undergo many structural and chemical changes which affect the mechanical properties. A complete transformation of fracture behavior was observed in the N{sub 2} treated LSFT samples. Further results to investigate the origin of the slow kinetics on reduction of ferrites have been obtained. The slow kinetics appear to be related to a non-equilibrium reduction pathway that initially results in the formation of iron particles. At long times, equilibrium can be reestablished with recovery of the perovskite phase. Recent results on transient kinetic data are presented. The 2-D modeling of oxygen movement has been undertaken in order to fit isotope data. The model is used to study ''frozen'' profiles in patterned or composite membranes.

S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

2005-02-01T23:59:59.000Z

32

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped Ti-substituted perovskites, La{sub 0.7}Sr{sub 0.3}Mn{sub 1-x}Ti{sub x}O{sub 3}, with 0 {le} x {le} 0.20, were investigated by neutron diffraction, magnetization, electric resistivity, and magnetoresistance (MR) measurements. All samples show a rhombohedral structure (space group R3C) from 10 K to room temperature. At room temperature, the cell parameters a, c and the unit cell volume increase with increasing Ti content. However, at 10 K, the cell parameter a has a maximum value for x = 0.10, and decreases for x > 0.10, while the unit cell volume remains nearly constant for x > 0.10. The average (Mn,Ti)-O bond length increases up to x = 0.15, and the (Mn,Ti)-O-(Mn,Ti) bond angle decreases with increasing Ti content to its minimum value at x = 0.15 at room temperature. Below the Curie temperature TC, the resistance exhibits metallic behavior for the x {le} 0.05 samples. A metal (semiconductor) to insulator transition is observed for the x {ge} 0.10 samples. A peak in resistivity appears below TC for all samples, and shifts to a lower temperature as x increases. The substitution of Mn by Ti decreases the 2p-3d hybridization between O and Mn ions, reduces the bandwidth W, and increases the electron-phonon coupling. Therefore, the TC shifts to a lower temperature and the resistivity increases with increasing Ti content. A field-induced shift of the resistivity maximum occurs at x {le} 0.10 compounds. The maximum MR effect is about 70% for La{sub 0.7}Sr{sub 0.3}Mn{sub 0.8}Ti{sub 0.2}O{sub 3}. The separation of TC and the resistivity maximum temperature T{sub {rho},max} enhances the MR effect in these compounds due to the weak coupling between the magnetic ordering and the resistivity as compared with La{sub 0.7}Sr{sub 0.3}MnO{sub 3}. The bulk densities of the membranes were determined using the Archimedes method. The bulk density was 5.029 and 5.57 g/cc for LSFT and dual phase membranes, respectively. The microstructure of the dual phase membrane was analyzed using SEM. It is evident from the micrograph that the microstructure is composed of dual phases. The dense circular regions are enclosed by the less dense, continuous phase which accommodates most of the pores. The pores are normally aggregated and found clustered along the dense regions where as the dense regions do not have pores. Upon closer observation of the micrograph it is revealed that the dense region has a clear circular cleavage or crack as their boundary. The circular cleavage clearly encompasses a dense region and which consists of no pore or any flaw that is visible. The size distribution of the dense, discontinuous regions is varying from 5 to 20 {micro}m with a D{sub 50} of 15 {micro}m. The grain size distribution was estimated from the micrographs using image analysis and a unimodal distribution of grains was observed with an average grain size of 1.99 {micro}m. The chemical compositions of the membranes were analyzed using EDS analysis and no other impurities were observed. The XRD analysis was carried out for the membranes and the phase purity was confirmed. The fracture toughness of LSFT membranes at room temperature has to be calculated using the Vickers indentation method. An electrochemical cell has been designed and built for measurements of the ionic conductivity by the use of blocking electrodes. Preliminary measurements on La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} are reported. Modifications to the apparatus to improve the data quality have been completed. Electron microscopy studies of the origin of the slow kinetics on reduction of ferrites have been initiated. A series of isotope transients under air separation mode (small gradient) were completed on the membrane of LSCrF-2828 at 900 C. Low pO{sub 2} atmospheres based on with CO-CO{sub 2} mixtures have also been admitted to the delivery side of the LSCrF-2828 membrane to produce the gradient

S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

2005-05-01T23:59:59.000Z

33

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

Ti doping on La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} (LSF) tends to increase the oxygen equilibration kinetics of LSF in lower oxygen activity environment because of the high valence state of Ti. However, the addition of Ti decreases the total conductivity because the acceptor ([Sr{prime}{sub La}]) is compensated by the donor ([Ti{sub Fe}{sup {sm_bullet}}]) which decreases the carrier concentration. The properties of La{sub 0.2}Sr{sub 0.8}Fe{sub 1-x}Ti{sub x}O{sub 3-{delta}} (LSFT, x = 0.45) have been experimentally and theoretically investigated to elucidate (1) the dependence of oxygen occupancy and electrochemical properties on temperature and oxygen activity by thermogravimetric analysis (TGA) and (2) the electrical conductivity and carrier concentration by Seebeck coefficient and electrical measurements. In the present study, dual phase (La{sub 0.2}Sr{sub 0.8}Fe{sub 0.6}Ti{sub 0.4}O{sub 3-{delta}}/Ce{sub 0.9}Gd{sub 0.1}O{sub 2-{delta}}) membranes have been evaluated for structural properties such as hardness, fracture toughness and flexural strength. The effect of high temperature and slightly reducing atmosphere on the structural properties of the membranes was studied. The flexural strength of the membrane decreases upon exposure to slightly reducing conditions at 1000 C. The as-received and post-fractured membranes were characterized using XRD, SEM and TG-DTA to understand the fracture mechanisms. Changes in structural properties of the composite were sought to be correlated with the physiochemical features of the two-phases. We have reviewed the electrical conductivity data and stoichiometry data for La{sub 0.2}Sr{sub 0.8}Cr{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} some of which was reported previously. Electrical conductivity data for La{sub 0.2}Sr{sub 0.8}Cr{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} (LSCrF) were obtained in the temperature range, 752 {approx} 1055 C and in the pO{sub 2} range, 10{sup -18} {approx} 0.5 atm. The slope of the plot of log {sigma} vs. log pO{sub 2} is {approx} 1/5 in the p-type region, pO{sub 2} = 10{sup -5} {approx} 10{sup -1} atm. The pO{sub 2} at which the p-n transition is observed increases with increasing temperature. The activation energy for ionic conduction was estimated to be 0.86 eV from an Arrhenius plot of the minimum conductivity vs. reciprocal temperature. At temperatures below 940 C, a plateau in the conductivity isotherm suggests the presence of a two-phase region. Most likely, phase separation occurs to form a mixture of a perovskite phase and an oxygen vacancy ordered phase related to brownmillerite. Additional data for the oxygen non stoichiometry are presented.

S. Bandopadhyay; T. Nithyanantham

2006-12-31T23:59:59.000Z

34

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

A non-agglomerated and nanocrystalline-sized powder was successfully produced using ethylene glycol nitrate methods. The LSFT powder prepared using this method exhibits well dispersed and nano-sized particles about 100-200 nm. The density of LSFT sintered at 1300 C was about 90% of the theoretical density at which is 100 C less than that of the previous LSFT which was sintered at 1400 C. The sample sintered at 1400 C exhibited the evidence of a liquid phase at the grain boundaries and 2nd phase formation which probably caused low mechanical stability. The electrical conductivity and Seebeck coefficient were measured as a function of temperature. The LSFT-CGO specimens were cut from the as sintered bars and used for the evaluation of Mechanical Properties after polishing. The effect of strain rate on the flexural strength of the LSFT-CGO test specimens was studied. Three strain rates 6, 60 and 600 {micro}m/ min were chosen for this study. It is observed from the results that with increasing cross head speed the membrane takes higher loads to fail. A reduction in the strength of the membrane was observed at 1000 C in N{sub 2}. Two different routes were investigated to synthesis GDC using either formate or carbonate precursors. The precursor and CGO particle morphologies were examined by scanning electron microscopy. The thermal decomposition behaviors of Ce(Gd)(HCOO){sub 3} and Ce(Gd)(CO{sub 3})(OH) were determined by thermogravimetric analysis (TGA) at a rate of 3 C/min in air. The X-ray powder diffraction patterns of the precursor and CGO were collected and nitrogen adsorption isotherms were measured. Conductivity measurements were made by AC impedance spectroscopy on sintered disks in air using platinum electrodes.

S. Bandopadhyay; T. Nithyanantham

2006-06-30T23:59:59.000Z

35

Membrane Transport Chloride Transport Across Vesicle and Cell  

E-Print Network [OSTI]

Membrane Transport Chloride Transport Across Vesicle and Cell Membranes by Steroid-Based Receptors-established that molecules which transport cations across cell membranes (cationophores) can have potent biological effects the formation of an ion pair.[4a­g] Anion transport by purely electroneutral systems is still quite rare.[4j

Smith, Bradley D.

36

Oxygen Transport Ceramic Membranes Quarterly Report  

E-Print Network [OSTI]

/Reaction rates in Ion 21 Transport Membranes using Isotope Tracer and Transient Kinetic Techniques CONCLUSIONS 30Oxygen Transport Ceramic Membranes Quarterly Report January 2003 ­ March 2003 Principal Authors on the thermodynamic properties of the membrane materials are continued to develop a complete model for the membrane

Eagar, Thomas W.

37

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and initial studies on newer composition of Ti doped LSF. Dense OTM bars provided by Praxair were loaded to fracture at varying stress rates. Studies were done at room temperature in air and at 1000 C in a specified environment to evaluate slow crack growth behavior. In addition, studies were also begun to obtain reliable estimates of fracture toughness and stable crack growth in specific environments. Newer composition of Ti doped LSF membranes were characterized by neutron diffraction analysis. Quench studies indicated an apparent correlation between the unit cell volume and oxygen occupancy. The studies however, indicated an anomaly of increasing Fe/Ti ratio with change in heat treatment. Ti doped LSF was also characterized for stoichiometry as a function of temp and pO{sub 2}. The non stoichiometry parameter {delta} was observed to increase almost linearly on lowering pO{sub 2} until a ideal stoichiometric composition of {delta} = 0.175 was approached.

S. Bandopadhyay; N. Nagabhushana; X.-D Zhou; W.B. Yelon; H.U. Anderson; Alan Jacobson; C.A. Mims

2004-02-01T23:59:59.000Z

38

Controlling membrane protein folding using photoresponsive surfactant.  

E-Print Network [OSTI]

??Membrane proteins perform a number of roles in biological function. Membrane lipids can self assembly into numerous different phases in aqueous solution, including micelles, vesicles (more)

Chang, Chia Hao

2012-01-01T23:59:59.000Z

39

Catalyst containing oxygen transport membrane  

SciTech Connect (OSTI)

A composite oxygen transport membrane having a dense layer, a porous support layer and an intermediate porous layer located between the dense layer and the porous support layer. Both the dense layer and the intermediate porous layer are formed from an ionic conductive material to conduct oxygen ions and an electrically conductive material to conduct electrons. The porous support layer has a high permeability, high porosity, and a high average pore diameter and the intermediate porous layer has a lower permeability and lower pore diameter than the porous support layer. Catalyst particles selected to promote oxidation of a combustible substance are located in the intermediate porous layer and in the porous support adjacent to the intermediate porous layer. The catalyst particles can be formed by wicking a solution of catalyst precursors through the porous support toward the intermediate porous layer.

Christie, Gervase Maxwell; Wilson, Jamie Robyn; van Hassel, Bart Antonie

2012-12-04T23:59:59.000Z

40

Evidence for a dynamic and transient pathway through the TAT protein transport machinery  

E-Print Network [OSTI]

, University of Florida, Gainesville FL, USA Tat systems transport completely folded proteins across ion Categories: membranes & transport; proteins Keywords: chloroplasts; protein transport; thylakoid; trans transport machinery in thylakoids (called cpTat) consists of three membrane proteins; Tha4, Hcf106, and cp

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


41

Ion transport membrane module and vessel system  

DOE Patents [OSTI]

An ion transport membrane system comprising (a) a pressure vessel having an interior, an exterior, an inlet, and an outlet; (b) a plurality of planar ion transport membrane modules disposed in the interior of the pressure vessel and arranged in series, each membrane module comprising mixed metal oxide ceramic material and having an interior region and an exterior region, wherein any inlet and any outlet of the pressure vessel are in flow communication with exterior regions of the membrane modules; and (c) one or more gas manifolds in flow communication with interior regions of the membrane modules and with the exterior of the pressure vessel. The ion transport membrane system may be utilized in a gas separation device to recover oxygen from an oxygen-containing gas or as an oxidation reactor to oxidize compounds in a feed gas stream by oxygen permeated through the mixed metal oxide ceramic material of the membrane modules.

Stein, VanEric Edward (Allentown, PA); Carolan, Michael Francis (Allentown, PA); Chen, Christopher M. (Allentown, PA); Armstrong, Phillip Andrew (Orefield, PA); Wahle, Harold W. (North Canton, OH); Ohrn, Theodore R. (Alliance, OH); Kneidel, Kurt E. (Alliance, OH); Rackers, Keith Gerard (Louisville, OH); Blake, James Erik (Uniontown, OH); Nataraj, Shankar (Allentown, PA); Van Doorn, Rene Hendrik Elias (Obersulm-Willsbach, DE); Wilson, Merrill Anderson (West Jordan, UT)

2012-02-14T23:59:59.000Z

42

Ion transport membrane module and vessel system  

DOE Patents [OSTI]

An ion transport membrane system comprising (a) a pressure vessel having an interior, an exterior, an inlet, and an outlet; (b) a plurality of planar ion transport membrane modules disposed in the interior of the pressure vessel and arranged in series, each membrane module comprising mixed metal oxide ceramic material and having an interior region and an exterior region, wherein any inlet and any outlet of the pressure vessel are in flow communication with exterior regions of the membrane modules; and (c) one or more gas manifolds in flow communication with interior regions of the membrane modules and with the exterior of the pressure vessel.The ion transport membrane system may be utilized in a gas separation device to recover oxygen from an oxygen-containing gas or as an oxidation reactor to oxidize compounds in a feed gas stream by oxygen permeated through the mixed metal oxide ceramic material of the membrane modules.

Stein, VanEric Edward (Allentown, PA); Carolan, Michael Francis (Allentown, PA); Chen, Christopher M. (Allentown, PA); Armstrong, Phillip Andrew (Orefield, PA); Wahle, Harold W. (North Canton, OH); Ohrn, Theodore R. (Alliance, OH); Kneidel, Kurt E. (Alliance, OH); Rackers, Keith Gerard (Louisville, OH); Blake, James Erik (Uniontown, OH); Nataraj, Shankar (Allentown, PA); van Doorn, Rene Hendrik Elias (Obersulm-Willsbach, DE); Wilson, Merrill Anderson (West Jordan, UT)

2008-02-26T23:59:59.000Z

43

Evolution of Antiparallel Two-Domain Membrane Proteins. Swapping Domains in the Glutamate Transporter GltS  

Science Journals Connector (OSTI)

Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands ... We thank Fabrizia Fusetti of The Netherlands Proteomics Centre/Membrane Enzymology group of the University of Groningen for analyzing samples by mass spectrometry. ...

Adam Dobrowolski; Juke S. Lolkema

2010-06-17T23:59:59.000Z

44

Anion Exchange Membranes - Transport/Conductivity  

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

Fundamental understanding Fundamental understanding * Driving membranes towards applications Anion Exchange Membranes - Transport/Conductivity High Priority * A need for a standard/available AEM (similar to Nafion in PEMs) * Define standard experimental conditions and protocols * A need for much more fundamental studies in transport mechanisms and mechanical properties * A need to develop much more new AEMs with alternative chemistries (new cation and backbone chemistries) Fundamental Studies * TRANSPORT * Conductivity (pure OH - hard to measure) * Water content, λ * Diffusion coefficients, NMR * Drag coefficients * Transference * Solubility * Fundamental transport mechanisms for anion and water transport * Computational Modeling * MORPHOLOGY/CHEMISTRY * Vibrational Spectroscopy: FTIR, Raman

45

Liners for ion transport membrane systems  

SciTech Connect (OSTI)

Ion transport membrane system comprising (a) a pressure vessel comprising an interior, an exterior, an inlet, an inlet conduit, an outlet, and an outlet conduit; (b) a plurality of planar ion transport membrane modules disposed in the interior of the pressure vessel and arranged in series, each membrane module comprising mixed metal oxide ceramic material and having an interior region and an exterior region, wherein the inlet and the outlet of the pressure vessel are in flow communication with exterior regions of the membrane modules; (c) a gas manifold having an interior surface wherein the gas manifold is in flow communication with the interior region of each of the planar ion transport membrane modules and with the exterior of the pressure vessel; and (d) a liner disposed within any of the inlet conduit, the outlet conduit, and the interior surface of the gas manifold.

Carolan, Michael Francis (Allentown, PA); Miller, Christopher Francis (Macungie, PA)

2010-08-10T23:59:59.000Z

46

Characterization of a plasma membrane zinc transporter in rat brain  

E-Print Network [OSTI]

Ireland Ltd. Keywords: Ion transport; Membrane vesicles; Excitotoxicity; Zinc homeostasis; TransitionCharacterization of a plasma membrane zinc transporter in rat brain Robert A. Colvin* Department transport in the brain. This report provides convincing evidence of a zinc transporter in plasma membrane

47

Oxy-combustion: Oxygen Transport Membrane Development  

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

combustion: Oxygen Transport combustion: Oxygen Transport Membrane Development Background The mission of the U.S. Department of Energy's (DOE) Existing Plants, Emissions & Capture (EPEC) Research & Development (R&D) Program is to develop innovative environmental control technologies to enable full use of the nation's vast coal reserves, while at the same time allowing the current fleet of coal-fired power plants to comply with existing and emerging environmental regulations. The EPEC R&D

48

Ion Transport Through Cell Membrane Channels Jan Gomulkiewicz1  

E-Print Network [OSTI]

1 Ion Transport Through Cell Membrane Channels Jan Gomulkiewicz1 , Jacek Mikisz2 , and Stanislaw various models of ion transport through cell membrane channels. Recent experimental data shows that sizes for the life of a cell. In particular, a fundamental phenomenon is a transport of ions through cell membranes

Miekisz, Jacek

49

Composition variation and underdamped mechanics near membrane proteins and coats  

E-Print Network [OSTI]

We study the effect of membrane proteins on the shape, composition and thermodynamic stability of the surrounding membrane. When the coupling between membrane composition and curvature is strong enough the nearby composition and shape both undergo a transition from over-damped to under-damped spatial variation, well before the membrane becomes unstable in the bulk. This transition is associated with a change in the sign of the thermodynamic energy and hence has the unusual features that it can favour the early stages of coat assembly necessary for vesiculation (budding), while suppressing the activity of mechanosensitive membrane channels and transporters. Our results also suggest an approach to obtain physical parameters that are otherwise difficult to measure.

S. Alex Rautu; George Rowlands; Matthew S. Turner

2015-02-14T23:59:59.000Z

50

The Low Polarity of Many Membrane Proteins  

Science Journals Connector (OSTI)

...buried in the hydrophobic interior of the membrane. from their Thus, the polarity index appears to be a useful parameter for edia. the characterization of membrane proteins. 45.6 46.1 48.1 48.3 50.0 52.0 37 38 12 39 27 27 This work was supported...

Roderick A. Capaldi; Garret Vanderkooi

1972-01-01T23:59:59.000Z

51

Artificial oxygen transport protein  

DOE Patents [OSTI]

This invention provides heme-containing peptides capable of binding molecular oxygen at room temperature. These compounds may be useful in the absorption of molecular oxygen from molecular oxygen-containing atmospheres. Also included in the invention are methods for treating an oxygen transport deficiency in a mammal.

Dutton, P. Leslie

2014-09-30T23:59:59.000Z

52

Cellular mechanisms of membrane protein folding William R Skach  

E-Print Network [OSTI]

Cellular mechanisms of membrane protein folding William R Skach The membrane protein­folding. This Perspective will focus on emerging evidence that the RTC functions as a protein-folding machine that restricts. The process of polytopic (multispanning) membrane protein folding can be viewed as a series of sequential

Cai, Long

53

Fabrication of catalyzed ion transport membrane systems  

DOE Patents [OSTI]

Process for fabricating a catalyzed ion transport membrane (ITM). In one embodiment, an uncatalyzed ITM is (a) contacted with a non-reducing gaseous stream while heating to a temperature and for a time period sufficient to provide an ITM possessing anion mobility; (b) contacted with a reducing gaseous stream for a time period sufficient to provide an ITM having anion mobility and essentially constant oxygen stoichiometry; (c) cooled while contacting the ITM with the reducing gaseous stream to provide an ITM having essentially constant oxygen stoichiometry and no anion mobility; and (d) treated by applying catalyst to at least one of (1) a porous mixed conducting multicomponent metallic oxide (MCMO) layer contiguous with a first side of a dense layer of MCMO and (2) a second side of the dense MCMO layer. In another embodiment, these steps are carried out in the alternative order of (a), (d), (b), and (c).

Carolan, Michael Francis; Kibby, Charles Leonard

2013-06-04T23:59:59.000Z

54

Sartobind Protein A 75 Membrane Adsorbers Operating Instructions  

E-Print Network [OSTI]

Sartobind Protein A 75 Membrane Adsorbers Operating Instructions A Separation Technology Based on Microporous Membranes 85030-517-47 Storage conditions Sartobind Protein A 75 Membrane Adsorbers have. Introduction Sartobind Protein A adsorbers represent a new generation of anti- body purification devices based

Lebendiker, Mario

55

Self-assembled lipid and membrane protein polyhedral nanoparticles  

E-Print Network [OSTI]

Self-assembled lipid and membrane protein polyhedral nanoparticles Tamara Bastaa,1 , Hsin-Jui Wub,1 for review January 28, 2012) We demonstrate that membrane proteins and phospholipids can self-assemble for the self-assembly of lipids and membrane proteins into closed polyhedral structures that can potentially

Stowell, Michael

56

Membranes for nanometer-scale mass fast transport  

DOE Patents [OSTI]

Nanoporous membranes comprising single walled, double walled, and multiwalled carbon nanotubes embedded in a matrix material were fabricated for fluid mechanics and mass transfer studies on the nanometer scale and commercial applications. Average pore size can be 2 nm to 20 nm, or seven nm or less, or two nanometers or less. The membrane can be free of large voids spanning the membrane such that transport of material such as gas or liquid occurs exclusively through the tubes. Fast fluid, vapor, and liquid transport are observed. Versatile micromachining methods can be used for membrane fabrication. A single chip can comprise multiple membranes. These membranes are a robust platform for the study of confined molecular transport, with applications in liquid and gas separations and chemical sensing including desalination, dialysis, and fabric formation.

Bakajin, Olgica (San Leandro, CA); Holt, Jason (Berkeley, CA); Noy, Aleksandr (Belmont, CA); Park, Hyung Gyu (Oakland, CA)

2011-10-18T23:59:59.000Z

57

Advances in ion transport membrane technology for Syngas production  

Science Journals Connector (OSTI)

Abstract Ceramic, ion transport membranes for the production of Syngas (ITM Syngas) produce high pressure synthesis gas in a single unit operation from low pressure air and pre-reformed natural gas. Oxygen transport through ITM Syngas membranes occurs through a series of processes, including solid phase oxygen anion diffusion through the dense membrane and surface reactions on the air and reducing sides of the membrane. This paper focuses on the effect of adding porous layers to the syngas side or both sides of the membrane to increase the available surface area for the surface reactions. The highest fluxes are achieved by increasing the surface area on both sides of the membrane, indicating that both surface reactions are a significant resistance to oxygen transport.

C.F. Miller; Jack Chen; M.F. Carolan; E.P. Foster

2014-01-01T23:59:59.000Z

58

Low temperature thermal transport in partially perforated silicon nitride membranes.  

SciTech Connect (OSTI)

The thermal transport in partially trenched silicon nitride membranes has been studied in the temperature range from 0.3 to 0.6 K, with the transition edge sensor (TES), the sole source of membrane heating. The test configuration consisted of Mo/Au TESs lithographically defined on silicon nitride membranes 1 {micro}m thick and 6 mm{sup 2} in size. Trenches with variable depth were incorporated between the TES and the silicon frame in order to manage the thermal transport. It was shown that sharp features in the membrane surface, such as trenches, significantly impede the modes of phonon transport. A nonlinear dependence of thermal resistance on trench depth was observed. Partial perforation of silicon nitride membranes to control thermal transport could be useful in fabricating mechanically robust detector devices.

Yefremenko, V.; Wang, G.; Novosad, V.; Datesman, A.; Pearson, J.; Divan, R.; Chang, C. L.; Downes, T. P.; Mcmahon, J. J.; Bleem, L. E.; Crites, A. T.; Meyer, S. S.; Carlstrom, J. E.; Univ. of Chicago

2009-05-04T23:59:59.000Z

59

Membrane porters of ATP-binding cassette transport systems are polyphyletic  

E-Print Network [OSTI]

in Membrane porters of ATP-binding cassette transportin Membrane porters of ATP-binding cassette transportin Membrane porters of ATP-binding cassette transport

Wang, Bin

2010-01-01T23:59:59.000Z

60

Feed gas contaminant removal in ion transport membrane systems  

SciTech Connect (OSTI)

An oxygen ion transport membrane process wherein a heated oxygen-containing gas having one or more contaminants is contacted with a reactive solid material to remove the one or more contaminants. The reactive solid material is provided as a deposit on a support. The one or more contaminant compounds in the heated oxygen-containing gas react with the reactive solid material. The contaminant-depleted oxygen-containing gas is contacted with a membrane, and oxygen is transported through the membrane to provide transported oxygen.

Underwood, Richard Paul (Allentown, PA); Makitka, III, Alexander (Hatfield, PA); Carolan, Michael Francis (Allentown, PA)

2012-04-03T23:59:59.000Z

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


61

Microfluidic Generation of Lipidic Mesophases for Membrane Protein Crystallization  

E-Print Network [OSTI]

Microfluidic Generation of Lipidic Mesophases for Membrane Protein Crystallization Sarah L. Perry Mathews AVenue, Urbana, Illinois 61801 ReceiVed March 11, 2009 ABSTRACT: We report on a microfluidic conditions of membrane proteins from a membrane-like phase in sub-20 nL volumes. This integrated microfluidic

Kenis, Paul J. A.

62

Interfacial Water-Transport Effects in Proton-Exchange Membranes  

SciTech Connect (OSTI)

It is well known that the proton-exchange membrane is perhaps the most critical component of a polymer-electrolyte fuel cell. Typical membranes, such as Nafion(R), require hydration to conduct efficiently and are instrumental in cell water management. Recently, evidence has been shown that these membranes might have different interfacial morphology and transport properties than in the bulk. In this paper, experimental data combined with theoretical simulations will be presented that explore the existence and impact of interfacial resistance on water transport for Nafion(R) 21x membranes. A mass-transfer coefficient for the interfacial resistance is calculated from experimental data using different permeation cells. This coefficient is shown to depend exponentially on relative humidity or water activity. The interfacial resistance does not seem to exist for liquid/membrane or membrane/membrane interfaces. The effect of the interfacial resistance is to flatten the water-content profiles within the membrane during operation. Under typical operating conditions, the resistance is on par with the water-transport resistance of the bulk membrane. Thus, the interfacial resistance can be dominant especially in thin, dry membranes and can affect overall fuel-cell performance.

Kienitz, Brian; Yamada, Haruhiko; Nonoyama, Nobuaki; Weber, Adam

2009-11-19T23:59:59.000Z

63

Minor Antenna Proteins CP24 and CP26 Affect the Interactions between Photosystem II Subunits and the Electron Transport Rate in Grana Membranes of Arabidopsis  

Science Journals Connector (OSTI)

...the grana membranes, reduced capacity for nonphotochemical quenching...reaction centers (RCs) exploit solar energy to drive electrons from...gradient for ATP synthesis. The capacity of light absorption is increased...absorbed light exceeds the capacity to use reducing equivalents...

Silvia de Bianchi; Luca Dall'Osto; Giuseppe Tognon; Tomas Morosinotto; Roberto Bassi

2008-04-01T23:59:59.000Z

64

Sorting of inner nuclear membrane-directed proteins at the endoplasmic reticulum membrane  

E-Print Network [OSTI]

-directed proteins were integrated cotranslationally through the endoplasmic reticulum translocon, and their nonrandom photocrosslinking to two translocon proteins, Sec61 and translocating chain-associated membrane protein (TRAM), revealed that the first...

Saksena, Suraj

2006-04-12T23:59:59.000Z

65

MICROFLUIDIC DEVICE FOR SUPER-FAST EVALUATION OF MEMBRANE PROTEIN  

E-Print Network [OSTI]

MICROFLUIDIC DEVICE FOR SUPER-FAST EVALUATION OF MEMBRANE PROTEIN CRYSTALLIZATION Hsin-Jui Wu1- throughput membraneless microfluidic device to fast produce the reconstitution of membrane protein in microfluidic channel can be completed in seconds to form protein/lipid particles under multiple conditions

Stowell, Michael

66

NETL: Gasification - Advanced Hydrogen Transport Membranes for Coal  

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

Syngas Processing Systems Syngas Processing Systems Advanced Hydrogen Transport Membranes for Coal Gasification Praxair Inc. Project Number: FE0004908 Project Description Praxair is conducting research to develop hydrogen transport membrane (HTM) technology to separate carbon dioxide (CO2) and hydrogen (H2) in coal-derived syngas for IGCC applications. The project team has fabricated palladium based membranes and measured hydrogen fluxes as a function of pressure, temperature, and membrane preparation conditions. Membranes are a commercially-available technology in the chemical industry for CO2 removal and H2 purification. There is, however, no commercial application of membrane processes that aims at CO2 capture for IGCC syngas. Due to the modular nature of the membrane process, the design does not exhibit economy of scale-the cost of the system will increase linearly as the plant system scale increases making the use of commercially available membranes, for an IGCC power plant, cost prohibitive. For a membrane process to be a viable CO2 capture technology for IGCC applications, a better overall performance is required, including higher permeability, higher selectivity, and lower membrane cost.

67

Nanostructured Silicon Membranes for Control of Molecular Transport  

SciTech Connect (OSTI)

A membrane that allows selective transport of molecular species requires precise engineering on the nanoscale. Membrane permeability can be tuned by controlling the physical structure of the pores. Here, a combination of electron-beam and optical lithography, along with cryogenic deep reactive ion etching, has been used to fabricate silicon membranes that are physically robust, have uniform pore-sizes, and are directly integrated into a microfluidic network. Additional reductions in pore size were achieved using plasma enhanced chemical vapor deposition of silicon dioxide to coat membrane surfaces. Cross sectioning of the membranes using focused ion beam milling was used to determine the physical shape of the membrane pores before and after coating.

Srijanto, Bernadeta R [ORNL] [ORNL; Retterer, Scott T [ORNL] [ORNL; Fowlkes, Jason Davidson [ORNL] [ORNL; Doktycz, Mitchel John [ORNL] [ORNL

2010-01-01T23:59:59.000Z

68

Review Lecture: Energy States of Proteins, Enzymes and Membranes  

Science Journals Connector (OSTI)

...phase. All the different energy states have been put to...and within membranes in energy conversion from charge separation to ATP formation. Energy states of proteins, enzymes...Journal Article Review | 0 Carrier Proteins 0 Cytochrome...

1978-01-01T23:59:59.000Z

69

Vesicle-associated membrane protein 2 mediates trafficking of {alpha}5{beta}1 integrin to the plasma membrane  

SciTech Connect (OSTI)

Integrins are major receptors for cell adhesion to the extracellular matrix (ECM). As transmembrane proteins, the levels of integrins at the plasma membrane or the cell surface are ultimately determined by the balance between two vesicle trafficking events: endocytosis of integrins at the plasma membrane and exocytosis of the vesicles that transport integrins. Here, we report that vesicle-associated membrane protein 2 (VAMP2), a SNARE protein that mediates vesicle fusion with the plasma membrane, is involved in the trafficking of {alpha}5{beta}1 integrin. VAMP2 was present on vesicles containing endocytosed {beta}1 integrin. Small interfering RNA (siRNA) silencing of VAMP2 markedly reduced cell surface {alpha}5{beta}1 and inhibited cell adhesion and chemotactic migration to fibronectin, the ECM ligand of {alpha}5{beta}1, without altering cell surface expression of {alpha}2{beta}1 integrin or {alpha}3{beta}1 integrin. By contrast, silencing of VAMP8, another SNARE protein, had no effect on cell surface expression of the integrins or cell adhesion to fibronectin. In addition, VAMP2-mediated trafficking is involved in cell adhesion to collagen but not to laminin. Consistent with disruption of integrin functions in cell proliferation and survival, VAMP2 silencing diminished proliferation and triggered apoptosis. Collectively, these data indicate that VAMP2 mediates the trafficking of {alpha}5{beta}1 integrin to the plasma membrane and VAMP2-dependent integrin trafficking is critical in cell adhesion, migration and survival.

Hasan, Nazarul [Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, 319 Abraham Flexner Way, Room 515, Louisville, KY 40202 (United States)] [Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, 319 Abraham Flexner Way, Room 515, Louisville, KY 40202 (United States); Hu, Chuan, E-mail: chuan.hu@louisville.edu [Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, 319 Abraham Flexner Way, Room 515, Louisville, KY 40202 (United States)] [Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, 319 Abraham Flexner Way, Room 515, Louisville, KY 40202 (United States)

2010-01-01T23:59:59.000Z

70

Ultraviolet resonance Raman spectroscopy of the integral membrane protein OmpA : elucidating structure and tryptophan microenvironment of folded and unfolded states  

E-Print Network [OSTI]

Intermediates in Membrane Protein Folding, Biochemistry (Intermediates in Membrane Protein Folding, Biochemistry (Engelman. Membrane-Protein Folding and Oligomerization -

Neary, Tiffany Jonean

2008-01-01T23:59:59.000Z

71

Protein-driven membrane stresses in fusion and fission  

E-Print Network [OSTI]

hypotheses on how specific proteins act in the two types of membrane remodeling. Mechanics of fusionProtein-driven membrane stresses in fusion and fission Michael M. Kozlov1 , Harvey T. McMahon2 undergo continuous remodeling. Ex- ocytosis and endocytosis, mitochondrial fusion and fis- sion, entry

McMahon, Harvey

72

Alkylsulfonates as Probes of Uncoupling Protein Transport ION PAIR TRANSPORT DEMONSTRATES THAT DIRECT H TRANSLOCATION BY UCP1 IS NOT NECESSARY  

E-Print Network [OSTI]

Alkylsulfonates as Probes of Uncoupling Protein Transport Mechanism ION PAIR TRANSPORT DEMONSTRATES of Membrane Transport Biophysics, Institute of Physiology, Academy of Sciences, Prague 14220, Czech Republic is transported with the neutral ion pair, the sulfonate is able to deliver protons across the bilayer, behaving

Garlid, Keith

73

Ammonium Bicarbonate Transport in Anion Exchange Membranes for Salinity Gradient Energy  

Science Journals Connector (OSTI)

Ammonium Bicarbonate Transport in Anion Exchange Membranes for Salinity Gradient Energy ... Current status of ion exchange membranes for power generation from salinity gradients ...

Geoffrey M. Geise; Michael A. Hickner; Bruce E. Logan

2013-08-22T23:59:59.000Z

74

Hydrogen transport membranes for dehydrogenation reactions  

DOE Patents [OSTI]

A method of converting C.sub.2 and/or higher alkanes to olefins by contacting a feedstock containing C.sub.2 and/or higher alkanes with a first surface of a metal composite membrane of a sintered homogenous mixture of an Al oxide or stabilized or partially stabilized Zr oxide ceramic powder and a metal powder of one or more of Pd, Nb, V, Zr, Ta and/or alloys or mixtures thereof. The alkanes dehydrogenate to olefins by contact with the first surface with substantially only atomic hydrogen from the dehydrogenation of the alkanes passing through the metal composite membrane. Apparatus for effecting the conversion and separation is also disclosed.

Balachandran; Uthamalingam (Hinsdale, IL)

2008-02-12T23:59:59.000Z

75

Electrochemical control of ion transport through a mesoporous carbon membrane  

SciTech Connect (OSTI)

The transport of fluids through nanometer scale channels typically on the order of 1 -100 nm often exhibit unique properties compared to the bulk fluid. These phenomena occur because the channel dimensions and molecular size become comparable to the range of several important forces including electrostatic and van der Waals forces. Small changes in properties such as the electric double layer or surface charge can significantly affect molecular transport through the channels. Based on these emerging properties, a variety of nanofluidic devices such as nanofluidic transistors, nanofluidic diodes or lab-on-a-chip devices have been developed3-7 with a diverse range of applications including water purification, biomolecular sensing, DNA separation, and rectified ion transport. Nanofluidic devices are typically fabricated using expensive lithography techniques or sacrificial templates. Here we report a carbon-based, three-dimensional nanofluidic transport membrane that enables gated, or on/off, control of the transport of organic molecular species and metal ions using an applied electrical potential. In the absence of an applied potential, both cationic and anionic molecules freely diffuse across the membrane via a concentration gradient. However, when an electrochemical potential is applied, the transport of ions through the membrane is inhibited.

Surwade, Sumedh P [ORNL] [ORNL; Chai, Songhai [ORNL] [ORNL; Choi, Jai-Pil [ORNL] [ORNL; Wang, Xiqing [ORNL] [ORNL; Lee, Jeseung [ORNL] [ORNL; Vlassiouk, Ivan V [ORNL] [ORNL; Mahurin, Shannon Mark [ORNL] [ORNL; Dai, Sheng [ORNL] [ORNL

2014-01-01T23:59:59.000Z

76

Controlling membrane protein folding with light illumination and catanionic surfactant systems.  

E-Print Network [OSTI]

??Membrane proteins are of significant importance, performing a variety of biological functions including pumps, channels, and receptors. Thus, membrane proteins represent attractive candidates as drug (more)

Zhang, Jing

2008-01-01T23:59:59.000Z

77

E-Print Network 3.0 - abnormal membrane proteins Sample Search...  

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

membrane and secreted proteins begin their journey to the surface. Only... of protein folding in the ER coupled across the ER membrane to cytosolic effector domains that...

78

Feed gas contaminant control in ion transport membrane systems  

DOE Patents [OSTI]

Ion transport membrane oxidation system comprising an enclosure having an interior and an interior surface, inlet piping having an internal surface and adapted to introduce a heated feed gas into the interior of the enclosure, and outlet piping adapted to withdraw a product gas from the interior of the enclosure; one or more planar ion transport membrane modules disposed in the interior of the enclosure, each membrane module comprising mixed metal oxide material; and a preheater adapted to heat a feed gas to provide the heated feed gas to the inlet piping, wherein the preheater comprises an interior surface. Any of the interior surfaces of the enclosure, the inlet piping, and the preheater may be lined with a copper-containing metal lining. Alternatively, any of the interior surfaces of the inlet piping and the preheater may be lined with a copper-containing metal lining and the enclosure may comprise copper.

Carolan, Michael Francis (Allentown, PA); Minford, Eric (Laurys Station, PA); Waldron, William Emil (Whitehall, PA)

2009-07-07T23:59:59.000Z

79

Multicomponent Transport through Realistic Zeolite Membranes: Characterization & Transport in Nanoporous Networks  

SciTech Connect (OSTI)

These research studies focused on the characterization and transport for porous solids which comprise both microporosity and mesoporosity. Such materials represent membranes made from zeolites as well as for many new nanoporous solids. Several analytical sorption techniques were developed and evaluated by which these multi-dimensional porous solids could be quantitatively characterized. Notably an approach by which intact membranes could be studied was developed and applied to plate-like and tubular supported zeolitic membranes. Transport processes were studied experimentally and theoretically based on the characterization studies.

William C. Conner

2007-08-02T23:59:59.000Z

80

Facilitated transport membrane hybrid systems for olefin purification  

SciTech Connect (OSTI)

A new membrane system has been developed by BP for refinery and chemical plant olefin purification and recovery. This facilitated transport system, coupled with distillation, offers lower capital and operating costs than conventional distillation alone. Initial results on lab scale hollow fiber devices indicate membrane flux ranging from 8.75 {times} 10{sup {minus}6} to 8 {times} 10{sup {minus}5} m{sup 3}/m{sup 2}/sec (2.5 to 23 scfd/ft{sub 2}) and selectivities from 150 to 300. Pilot plant experiments on propylene/propane and ethylene purge gas recovery over three to six months duration show membrane stability and product purity of 98.5% or greater using refinery grade propylene feed. Hybrid system optimization data for membranes and distillation indicate that using a side draw from the distillation tower provides advantages in terms of membrane area, purity of feed to the membrane, and low per-pass recovery coupled with high overall propylene recovery. Membrane performance data under various conditions are also presented. In addition to performance data, economic evaluation and energy savings are discussed.

Davis, J.C.; Valus, R.J.; Eshraghi, R.; Velikoff, A.E. [BP Research, Cleveland, OH (United States)

1993-01-01T23:59:59.000Z

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


81

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

SciTech Connect (OSTI)

Eltron Research Inc., and team members, are developing an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. This project was motivated by the National Energy Technology Laboratory (NETL) Vision 21 initiative which seeks to economically eliminate environmental concerns associated with the use of fossil fuels. This objective is being pursued using dense membranes based in part on Eltron-patented ceramic materials with a demonstrated ability for proton and electron conduction. The technical goals are being addressed by modifying single-phase and composite membrane composition and microstructure to maximize proton and electron conductivity without loss of material stability. Ultimately, these materials must enable hydrogen separation at practical rates under ambient and high-pressure conditions, without deactivation in the presence of feedstream components such as carbon dioxide, water, and sulfur. During this quarter, ceramic, cermet (ceramic/metal), and thin film membranes were prepared, characterized, and evaluated for H{sub 2} transport. For selected ceramic membrane compositions an optimum range for transition metal doping was identified, and it was determined that highest proton conductivity occurred for two-phase ceramic materials. Furthermore, a relationship between transition metal dopant atomic number and conductivity was observed. Ambipolar conductivities of {approx}6 x 10{sup -3} S/cm were achieved for these materials, and {approx} 1-mm thick membranes generated H{sub 2} transport rates as high as 0.3 mL/min/cm{sup 2}. Cermet membranes during this quarter were found to have a maximum conductivity of 3 x 10{sup -3} S/cm, which occurred at a metal phase contact of 36 vol.%. Homogeneous dense thin films were successfully prepared by tape casting and spin coating; however, there remains an unacceptably high difference in shrinkage rates between the film and support, which led to membrane instability. Further improvements in high pressure membrane seals also were achieved during this quarter, and a maximum pressure of 100 psig was attained. CoorsTek optimized many of the processing variables relevant to manufacturing scale production of ceramic H{sub 2} transport membranes, and SCI used their expertise to deposit a range of catalysts compositions onto ceramic membrane surfaces. Finally, MTI compiled relevant information regarding Vision 21 fossil fuel plant operation parameters, which will be used as a starting point for assessing the economics of incorporating a H{sub 2} separation unit.

Shane E. Roark; Tony F. Sammells; Richard A. Mackay; Adam E. Calihman; Lyrik Y. Pitzman; Tom F. Barton; Sara L. Rolfe; Richard N. Kleiner; James E. Stephan; Mike J. Holmes; Aaron L. Wagner

2001-07-30T23:59:59.000Z

82

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

SciTech Connect (OSTI)

Eltron Research Inc., and team members CoorsTek, McDermott Technology, Inc., Sued Chemie, Argonne National Laboratory and Oak Ridge National Laboratory are developing an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. This project was motivated by the National Energy Technology Laboratory (NETL) Vision 21 initiative which seeks to economically eliminate environmental concerns associated with the use of fossil fuels. This objective is being pursued using dense membranes based in part on Eltron-patented ceramic materials with a demonstrated ability for proton and electron conduction. The technical goals are being addressed by modifying single-phase and composite membrane composition and microstructure to maximize proton and electron conductivity without loss of material stability. Ultimately, these materials must enable hydrogen separation at practical rates under ambient and high-pressure conditions, without deactivation in the presence of feedstream components such as carbon dioxide, water, and sulfur. During this quarter, mixed proton/electron conductivity and hydrogen transport was measured as a function of metal phase content for a range of ceramic/metal (cermet) compositions. It was found that optimum performance occurred at 44 wt.% metal content for all compositions tested. Although each cermet appeared to have a continuous metal phase, it is believed that hydrogen transport increased with increasing metal content partially due to beneficial surface catalyst characteristics resulting from the metal phase. Beyond 44 wt.% there was a reduction in hydrogen transport most likely due to dilution of the proton conducting ceramic phase. Hydrogen separation rates for 1-mm thick cermet membranes were in excess of 0.1 mL/min/cm{sup 2}, which corresponded to ambipolar conductivities between 1 x 10{sup -3} and 8 x 10{sup -3} S/cm. Similar results were obtained for multiphase ceramic membranes comprised of a proton-conducting perovskite and electron conducting metal oxide. These multi-phase ceramic membranes showed only a slight improvement in hydrogen transport upon addition of a metal phase. The highest hydrogen separation rates observed this quarter were for a cermet membrane containing a hydrogen transport metal. A 1-mm thick membrane of this material achieved a hydrogen separation rate of 0.3 mL/min/cm{sup 2} at only 700 C, which increased to 0.6 mL/min/cm{sup 2} at 950 C.

Shane E. Roark; Tony F. Sammells; Richard A. Mackay; Lyrik Y. Pitzman; Alexandra Z. LaGuardia; Tom F. Barton; Sara L. Rolfe; Richard N. Kleiner; James E. Stephan; Mike J. Holmes; Aaron L. Wagner

2001-10-30T23:59:59.000Z

83

Improving protein crystal quality by selective removal of a Ca2+-dependent membrane-insertion loop  

Science Journals Connector (OSTI)

Protein engineering dramatically enhances the quality of crystals of a Ca2+-dependent membrane-binding protein.

Neau, D.B.

2007-10-24T23:59:59.000Z

84

Proteomic analysis of gliosomes from mouse brain: identification and investigation of glial membrane proteins  

Science Journals Connector (OSTI)

Proteomic analysis of gliosomes from mouse brain: identification and investigation of glial membrane proteins ...

Karen E. Carney; Marco Milanese; Pim van Nierop; Ka Wan Li; Stphane H.R. Oliet; August B. Smit; Giambattista Bonanno; Mark H.G. Verheijen

2014-10-13T23:59:59.000Z

85

IFITM Proteins Restrict Viral Membrane Hemifusion  

E-Print Network [OSTI]

an intermediate of fusion, referred to as a cold arrestedcold arrested state (CAS), PLOS Pathogens | www.plospathogens.org January 2013 | Volume 9 | Issue 1 | e1003124 Restriction of Viral Membrane Fusion

2013-01-01T23:59:59.000Z

86

Protein separations using porous silicon membranes  

E-Print Network [OSTI]

extraction, liquid/liquid extraction, and electrical processes. Of all of these, adsorption/chromatography and membrane separations are perhaps the most promising. According to Wong et al. (1987), chromatography offers very high selectivity but is riddled... heat transfer or heat generating equipment is necessary. The only utility required is electricity to drive pumps. A membrane separation unit operation can also be run at ambient temperature. When balanced against its drawbacks which include fouling...

Pass, Shannon Marie

1992-01-01T23:59:59.000Z

87

Ballistic electron transport in structured suspended semiconductor membranes  

SciTech Connect (OSTI)

We study ballistic electron transport in freely suspended AlAs/GaAs microstructures containing a high mobility two-dimensional electron gas with square lattice of antidots. We found that the magnetoresistance of the samples demonstrates commensurability oscillations both for the case of non-suspended and suspended devices. The temperature dependence of the commensurability oscillations is similar for both cases. However, the critical dc current, that suppresses these oscillations, in suspended samples is three times lower than in non-suspended ones. The observed phenomenon can be explained by peculiarities of the heat transport in membranes.

Pogosov, A. G.; Budantsev, M. V.; Zhdanov, E. Yu.; Pokhabov, D. A. [Institute of Semiconductor Physics SB RAS, Novosibirsk, Russia and Novosibirsk State University, Novosibirsk (Russian Federation)

2013-12-04T23:59:59.000Z

88

Nano-volume plates with excellent optical properties for fast, inexpensive crystallization screening of membrane proteins  

Science Journals Connector (OSTI)

A simple glass-based plate for screening the crystallization of membrane proteins in lipidic mesophases and of soluble proteins by the batch method is described. Trials with <20 ng membrane protein have been performed successfully.

Cherezov, V.

2003-11-15T23:59:59.000Z

89

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

SciTech Connect (OSTI)

Eltron Research Inc. and their team members are developing an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. This project was motivated by the National Energy Technology Laboratory (NETL) Vision 21 initiative which seeks to economically eliminate environmental concerns associated with the use of fossil fuels. This objective is being pursued using dense membranes based in part on Eltron-patented ceramic materials with a demonstrated ability for proton and electron conduction. The technical goals are being addressed by modifying single-phase and composite membrane composition and microstructure to maximize proton and electron conductivity without loss of material stability. Ultimately, these materials must enable hydrogen separation at practical rates under ambient and high-pressure conditions, without deactivation in the presence of feedstream components such as carbon dioxide, water, and sulfur. During this quarter, new cermet compositions were tested that demonstrated similar performance to previous materials. A 0.5-mm thick membrane achieved at H{sub 2} transport rate of 0.2 mL/min/cm{sup 2} at 950 C, which corresponded to an ambipolar conductivity of 3 x 10{sup -3} S/cm. Although these results were equivalent to those for other cermet compositions, this new composition might be useful if it demonstrates improved chemical or mechanical stability. Ceramic/ceramic composite membranes also were fabricated and tested; however, some reaction did occur between the proton- and electron-conducting phases, which likely compromised conductivity. This sample only achieved a H{sub 2} transport rate of {approx} 0.006 mL/min/cm{sup 2} and an ambipolar conductivity of {approx}4 x 10{sup -4} S/cm. Chemical stability tests were continued, and candidate ceramic membranes were found to react slightly with carbon monoxide under extreme testing conditions. A cermet compositions did not show any reaction with carbon monoxide, but a thick layer of carbon formed on the membrane surface. The most significant technical accomplishment this quarter was a new high-pressure seal composition. This material maintained a pressure differential across the membrane of {approx} 280 psi at 800 C, and is still in operation.

Shane E. Roark; Anthony F. Sammells; Richard A. Mackay; Lyrik Y. Pitzman; Thomas A. Zirbel; Thomas F. Barton; Sara L. Rolfe; U. (Balu) Balachandran; Richard N. Kleiner; James E. Stephan; Frank E. Anderson; George Farthing; Dan Rowley; Tim R. Armstrong; M.K. Ferber; Aaron L. Wagner; Jon P. Wagner

2002-07-30T23:59:59.000Z

90

FINAL REPORT:Observation and Simulations of Transport of Molecules and Ions Across Model Membranes  

SciTech Connect (OSTI)

During the this new grant we developed a robust methodology for investigating a wide range of properties of phospho-lipid bilayers. The approach developed is unique because despite using periodic boundary conditions, we can simulate an entire experiment or process in detail. For example, we can follow the entire permeation process in a lipid-membrane. This includes transport from the bulk aqueous phase to the lipid surface; permeation into the lipid; transport inside the lipid; and transport out of the lipid to the bulk aqueous phase again. We studied the transport of small gases in both the lipid itself and in model protein channels. In addition, we have examined the transport of nanocrystals through the lipid membrane, with the main goal of understanding the mechanical behavior of lipids under stress including water and ion leakage and lipid flip flop. Finally we have also examined in detail the deformation of lipids when under the influence of external fields, both mechanical and electrostatic (currently in progress). The important observations and conclusions from our studies are described in the main text of the report

MURAD, SOHAIL [University of Illinois at Chicago] [University of Illinois at Chicago; JAMESON, CYNTHIA J [University of Illinois at Chicago] [University of Illinois at Chicago

2013-10-22T23:59:59.000Z

91

Discrimination of outer membrane proteins using support vector machines  

Science Journals Connector (OSTI)

......discriminated with an accuracy of 94% from the pool of 1087 sequences, while correctly excluding...orthologous transporters by sequence/structure conservation. J. Mol. Biol., 332, 9991014. Chou...of amino acid preference at membrane-water interfaces. Bioinformatics, 18, 608616......

Keun-Joon Park; M. Michael Gromiha; Paul Horton; Makiko Suwa

2005-01-01T23:59:59.000Z

92

Transport of Alkali Halides through a Liquid Organic Membrane Containing a Ditopic Salt-Binding Receptor  

E-Print Network [OSTI]

in the solid state as contact ion pairs. Transport experiments, using a supported liquid membrane and high saltTransport of Alkali Halides through a Liquid Organic Membrane Containing a Ditopic Salt and anion receptors. All transport systems exhibit the same qualitative order of ion selectivity; that is

Smith, Bradley D.

93

pH dependence and compartmentalization of zinc transported across plasma membrane of rat cortical neurons  

E-Print Network [OSTI]

pH dependence and compartmentalization of zinc transported across plasma membrane of rat corticalH dependence and compartmental- ization of zinc transported across plasma membrane of rat cortical neurons. Am; ion transport; transition elements; primary culture IT IS KNOWN THAT Zn2 can enter neurons by two

94

Ionic transport in nanocapillary membrane systems Vikhram V. Swaminathan Larry R. Gibson II  

E-Print Network [OSTI]

. Keywords Membranes Á Nanostructures Á Nanofluidics Á Microfluidics Á Ion transport Á Electrokinetics Á lREVIEW Ionic transport in nanocapillary membrane systems Vikhram V. Swaminathan · Larry R. Gibson / Accepted: 23 May 2012 ? Springer Science+Business Media B.V. 2012 Abstract Species transport

95

Hydrogen bond dynamics in membrane protein function Ana-Nicoleta Bondar a,  

E-Print Network [OSTI]

Review Hydrogen bond dynamics in membrane protein function Ana-Nicoleta Bondar a, , Stephen H 30 November 2011 Available online 8 December 2011 Keywords: Membrane protein structure Hydrogen bond Membrane protein dynamics Lipid­protein interactions Changes in inter-helical hydrogen bonding

White, Stephen

96

Membrane vesicles: A simplified system for studying auxin transport  

SciTech Connect (OSTI)

Indoleacetic acid (IAA), the auxin responsible for regulation of growth, is transported polarly in plants. Several different models have been suggested to account for IAA transport by cells and its accumulation by membrane vesicles. One model sees diffusion of IAA driven by a pH gradient. The anion of a lipophilic weak acid like IAA or butyrate accumulates in an alkaline compartment in accord with the size of the pH gradient The accumulation of IAA may be diminished by the permeability of its lipophilic anion. This anion leak may be blocked by NPA. With anion efflux blocked, a gradient of two pH units would support an IAA accumulation of less than 50-fold at equilibrium (2) Another model sees diffusion of IAA in parallel with a saturable symport (IAA[sup [minus

Goldsmith, M.H.M.

1989-01-01T23:59:59.000Z

97

E-Print Network 3.0 - aeruginosa membrane transport Sample Search...  

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

U. The membrane-bound electron transport system of Methanosarcina species. J. Bioenerg. Biomembr... of methanophenazine and function of phenazines in ... Source: Dietrich,...

98

Charge Transport through a Novel Zeolite Y Membrane by a Self-Exchange Process Hyunjung Lee and Prabir K. Dutta*  

E-Print Network [OSTI]

Charge Transport through a Novel Zeolite Y Membrane by a Self-Exchange Process Hyunjung Lee-photoresist-coated membranes were found. Accessibility of the intrazeolitic volume was examined by ion exchange and for optimally illuminated membranes was comparable to uncoated membranes. Charge transport through the membrane

Dutta, Prabir K.

99

Ultraviolet resonance Raman and fluorescence studies of folded and unfolded conformations of the membrane protein OmpA  

E-Print Network [OSTI]

Thermodynamics of Membrane Protein Folding: Lessons from theA Model for Membrane Protein Folding, H. S. Shafaat, K. M.goals of membrane protein folding studies is to ascertain

Sanchez, Katheryn Marie

2010-01-01T23:59:59.000Z

100

Assembly and Repair of Membrane-Bound Electron Transport Complexes similar to NifS than is Slr0387, but shows strong  

E-Print Network [OSTI]

Assembly and Repair of Membrane-Bound Electron Transport Complexes similar to NifS than is Slr0387 in the maturation of FeS proteins. We found that under some conditions the Synechocystis NifU-like protein can oxidation of the cysteine side chains at NifU. The same reaction might have occurred in lysed chloroplasts

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


101

Similar Energetic Contributions of Packing in the Core of Membrane and Water-Soluble Proteins  

SciTech Connect (OSTI)

A major driving force for water-soluble protein folding is the hydrophobic effect, but membrane proteins cannot make use of this stabilizing contribution in the apolar core of the bilayer. It has been proposed that membrane proteins compensate by packing more efficiently. We therefore investigated packing contributions experimentally by observing the energetic and structural consequences of cavity creating mutations in the core of a membrane protein. We observed little difference in the packing energetics of water and membrane soluble proteins. Our results imply that other mechanisms are employed to stabilize the structure of membrane proteins.

Joh, Nathan H.; Oberai, Amit; Yang, Duan; Whitelegge, Julian P.; Bowie, James U.; (UCLA)

2009-09-15T23:59:59.000Z

102

ATP-binding cassette-like transporters are involved in the transport of lignin precursors across plasma and vacuolar membranes  

SciTech Connect (OSTI)

Lignin is a complex biopolymer derived primarily from the condensation of three monomeric precursors, the monolignols. The synthesis of monolignols occurs in the cytoplasm. To reach the cell wall where they are oxidized and polymerized, they must be transported across the cell membrane. However, the molecular mechanisms underlying the transport process are unclear. There are conflicting views about whether the transport of these precursors occurs by passive diffusion or is an energized active process; further, we know little about what chemical forms are required. Using isolated plasma and vacuolar membrane vesicles prepared from Arabidopsis, together with applying different transporter inhibitors in the assays, we examined the uptake of monolignols and their derivatives by these native membrane vesicles. We demonstrate that the transport of lignin precursors across plasmalemma and their sequestration into vacuoles are ATP-dependent primary-transport processes, involving ATP-binding cassette-like transporters. Moreover, we show that both plasma and vacuolar membrane vesicles selectively transport different forms of lignin precursors. In the presence of ATP, the inverted plasma membrane vesicles preferentially take up monolignol aglycones, whereas the vacuolar vesicles are more specific for glucoconjugates, suggesting that the different ATP-binding cassette-like transporters recognize different chemical forms in conveying them to distinct sites, and that glucosylation of monolignols is necessary for their vacuolar storage but not required for direct transport into the cell wall in Arabidopsis.

Miao, Y.C.; Liu, C.

2010-12-28T23:59:59.000Z

103

Continuum electromechanical modeling of protein-membrane interactions Y. C. Zhou*  

E-Print Network [OSTI]

and topological transformations of membrane are crucial steps in numerous transport and signaling processes of cells, includ- ing cell migration, membrane trafficking, and ion conduc- tance 1­3 . There are various sorting complex required for transport III ESCRT III in- duced membrane budding or protrusion 5

Lu, Benzhuo

104

NETL: Gasification - Development of Ion-Transport Membrane Oxygen  

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

Feed Systems Feed Systems Recovery Act: Development of Ion-Transport Membrane Oxygen Technology for Integration in IGCC and Other Advanced Power Generation Systems Air Products and Chemicals, Inc. Project Number: FC26-98FT40343 Project Description Air Products and Chemicals, Inc. is developing, scaling-up, and demonstrating a novel air separation technology for large-scale production of oxygen (O2) at costs that are approximately one-third lower than conventional cryogenic plants. An Ion Transport Membrane (ITM) Oxygen plant co-produces power and oxygen. A phased technology RD&D effort is underway to demonstrate all necessary technical and economic requirements for scale-up and industrial commercialization. The ITM Oxygen production technology is a radically different approach to producing high-quality tonnage oxygen and to enhance the performance of integrated gasification combined cycle and other advanced power generation systems. Instead of cooling air to cryogenic temperatures, oxygen is extracted from air at temperatures synergistic with power production operations. Process engineering and economic evaluations of integrated gasification combined cycle (IGCC) power plants comparing ITM Oxygen with a state-of-the-art cryogenic air separation unit are aimed to show that the installed capital cost of the air separation unit and the installed capital of IGCC facility are significantly lower compared to conventional technologies, while improving power plant output and efficiency. The use of low-cost oxygen in combustion processes would provide cost-effective emission reduction and carbon management opportunities. ITM Oxygen is an enabling module for future plants for producing coal derived shifted synthesis gas (a mixture of hydrogen [H2] and carbon dioxide [CO2]) ultimately for producing clean energy and fuels. Oxygen-intensive industries such as steel, glass, non-ferrous metallurgy, refineries, and pulp and paper may also realize cost and productivity benefits as a result of employing ITM Oxygen.

105

RAPID COMMUNICATION An Integral Membrane Green Fluorescent Protein Marker, Us9-GFP,  

E-Print Network [OSTI]

RAPID COMMUNICATION An Integral Membrane Green Fluorescent Protein Marker, Us9-GFP described GFP-spectrin, a membrane- localized derivative of the green fluorescent protein that can proteins employed in this assay. © 1999 Academic Press Key Words: green fluorescent protein; cell cycle

106

Transport coefficients of the D1-D5-P system and the membrane paradigm  

Science Journals Connector (OSTI)

I discuss a correspondence between string theory and the black hole membrane paradigm in the context of the D1-D5-P system. By using the Kubo formula, I calculate transport coefficients of the effective string model induced by two kinds of minimal scalars. Then, I show that these transport coefficients exactly agree with the corresponding membrane transport coefficients of a five-dimensional near-extremal black hole with three charges.

Yuya Sasai

2012-01-11T23:59:59.000Z

107

Oxygen transport membrane system and method for transferring heat to catalytic/process reactors  

DOE Patents [OSTI]

A method and apparatus for producing heat used in a synthesis gas production is provided. The disclosed method and apparatus include a plurality of tubular oxygen transport membrane elements adapted to separate oxygen from an oxygen containing stream contacting the retentate side of the membrane elements. The permeated oxygen is combusted with a hydrogen containing synthesis gas stream contacting the permeate side of the tubular oxygen transport membrane elements thereby generating a reaction product stream and radiant heat. The present method and apparatus also includes at least one catalytic reactor containing a catalyst to promote the stream reforming reaction wherein the catalytic reactor is surrounded by the plurality of tubular oxygen transport membrane elements. The view factor between the catalytic reactor and the plurality of tubular oxygen transport membrane elements radiating heat to the catalytic reactor is greater than or equal to 0.5.

Kelly, Sean M; Kromer, Brian R; Litwin, Michael M; Rosen, Lee J; Christie, Gervase Maxwell; Wilson, Jamie R; Kosowski, Lawrence W; Robinson, Charles

2014-01-07T23:59:59.000Z

108

Dynamical Observations of Membrane Proteins: The Case of Bacteriorhodopsin  

SciTech Connect (OSTI)

A new x-ray methodology, Diffracted X-ray Tracking (DXT), has been proven to be a valuable tool in observing intramolecular conformational changes of individual single molecules in real time and space. In order to achieve DXT, the fabrication of dispersive nanocrystals is one of the most important technologies, because DXT system monitors the diffracted x-ray (Laue) spots from nanocrystals labeled with single bio-molecules. In this study, we fabricated one-dimensional gold nanocrystals with an average diameter size of 16 nm using vacuum evaporation. Furthermore, using these nanocrystals, we succeeded in observing normal Brownian motions and momentary structural changes of a single-membrane protein (Bacteriorhodopsin: BR) in a membrane due to the expression of its function. The average movement of the momentarily structural changes in the 35th residue of BR was 76 {+-} 48 pm, and this agrees with estimated movements from known x-ray crystallography data. This result is an important step toward realizing in-vivo observations of single-molecular conformational changes in membrane proteins.

Okumura, Yasuaki [Department of Biomolecular Science and Technology, Shinshu University, Ueda, Nagano 386-8567 (Japan); Life and Environmental Science Div., Japan Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto Mikazuki-cho, Sayo-gun, Hyogo 679-5198 (Japan); CREST-Sasaki Team, Japan Science and Technology Corporation (JST), Tachikawa 190-0012 (Japan); Oka, Toshihiko [Life and Environmental Science Div., Japan Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto Mikazuki-cho, Sayo-gun, Hyogo 679-5198 (Japan); Taniguchi, Yoshio [Department of Biomolecular Science and Technology, Shinshu University, Ueda, Nagano 386-8567 (Japan); Sasaki, Yuji C. [Life and Environmental Science Div., Japan Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto Mikazuki-cho, Sayo-gun, Hyogo 679-5198 (Japan); CREST-Sasaki Team, Japan Science and Technology Corporation (JST), Tachikawa 190-0012 (Japan)

2004-05-12T23:59:59.000Z

109

Advanced Hydrogen Transport Membranes for Vision 21 Fossil Fuel Plants  

SciTech Connect (OSTI)

The objective of this project was to develop an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. A family of hydrogen separation membranes was developed including single phase mixed conducting ceramics, ceramic/ceramic composites, cermet membranes, cermet membranes containing a hydrogen permeable metal, and intermediate temperature composite layered membranes. Each membrane type had different operating parameters, advantages, and disadvantages that were documented over the course of the project. Research on these membranes progressed from ceramics to cermets to intermediate temperature composite layered membranes. During this progression performance was increased from 0.01 mL x min{sup -1} x cm{sup -2} up to 423 mL x min{sup -1} x cm{sup -2}. Eltron and team membranes not only developed each membrane type, but also membrane surface catalysis and impurity tolerance, creation of thin film membranes, alternative applications such as membrane promoted alkane dehydrogenation, demonstration of scale-up testing, and complete engineering documentation including process and mechanical considerations necessary for inclusion of Eltron membranes in a full scale integrated gasification combined cycle power plant. The results of this project directly led to a new $15 million program funded by the Department of Energy. This new project will focus exclusively on scale-up of this technology as part of the FutureGen initiative.

Carl R. Evenson; Shane E. Roark

2006-03-31T23:59:59.000Z

110

Interfacial Water-Transport Effects in Proton-Exchange Membranes  

E-Print Network [OSTI]

MaterialsModelinginPemFuelCells,A CombinationModelIonomerMembranesforPem?FuelCells,"ElectrochimicaActa,

Kienitz, Brian

2010-01-01T23:59:59.000Z

111

Numerical simulations of ion transport membrane oxy-fuel reactors for CO? capture applications  

E-Print Network [OSTI]

Numerical simulations were performed to investigate the key features of oxygen permeation and hydrocarbon conversion in ion transport membrane (ITM) reactors. ITM reactors have been suggested as a novel technology to enable ...

Hong, Jongsup

2013-01-01T23:59:59.000Z

112

Experimental characterization of an Ion Transport Membrane (ITM) reactor for methane oxyfuel combustion  

E-Print Network [OSTI]

Ion Transport Membranes (ITM) which conduct both electrons and oxygen ions have been investigated experimentally for oxygen separation and fuel (mostly methane) conversion purposes over the last three decades. The fuel ...

Apo, Daniel Jolomi

2012-01-01T23:59:59.000Z

113

Systems-level design of ion transport membrane oxy-combustion power plants  

E-Print Network [OSTI]

Oxy-fuel combustion, particularly using an integrated oxygen ion transport membrane (ITM), is a thermodynamically attractive concept that seeks to mitigate the penalties associated with CO 2 capture from power plants. ...

Mancini, Nicholas D. (Nicholas David)

2011-01-01T23:59:59.000Z

114

Transport properties of separating membranes MF-4SK during alkaline electrolysis of water  

Science Journals Connector (OSTI)

The transport properties of separating membranes MF-4SK are studied during electrolysis of H2O in solutions of KOH. The effective diffusion coefficients of molecules of KOH and H2O and the transfer coefficients o...

A. N. Ponomarev; Yu. L. Moskvin; S. D. Babenko

2007-03-01T23:59:59.000Z

115

Antibiotic assisted molecular ion transport across a membrane in real time  

E-Print Network [OSTI]

Antibiotic assisted molecular ion transport across a membrane in real time Jian Liu, Xiaoming Shang of various chemical and physical phenomena as well as applications such as solar energy conversion, catalysis

Eisenthal, Kenneth B.

116

Towards understanding of Nipah virus attachment protein assembly and the role of protein affinity and crowding for membrane curvature events.  

SciTech Connect (OSTI)

Pathogenic viruses are a primary threat to our national security and to the health and economy of our world. Effective defense strategies to combat viral infection and spread require the development of understanding of the mechanisms that these pathogens use to invade the host cell. We present in this report results of our research into viral particle recognition and fusion to cell membranes and the role that protein affinity and confinement in lipid domains plays in membrane curvature in cellular fusion and fission events. Herein, we describe 1) the assembly of the G attachment protein of Nipah virus using point mutation studies to define its role in viral particle fusion to the cell membrane, 2) how lateral pressure of membrane bound proteins induce curvature in model membrane systems, and 3) the role of membrane curvature in the selective partitioning of molecular receptors and specific affinity of associated proteins.

Stachowiak, Jeanne C.; Hayden, Carl C.; Negrete, Oscar A.; Davis, Ryan Wesley; Sasaki, Darryl Yoshio

2013-10-01T23:59:59.000Z

117

Ion transport membrane module and vessel system with directed internal gas flow  

DOE Patents [OSTI]

An ion transport membrane system comprising (a) a pressure vessel having an interior, an inlet adapted to introduce gas into the interior of the vessel, an outlet adapted to withdraw gas from the interior of the vessel, and an axis; (b) a plurality of planar ion transport membrane modules disposed in the interior of the pressure vessel and arranged in series, each membrane module comprising mixed metal oxide ceramic material and having an interior region and an exterior region; and (c) one or more gas flow control partitions disposed in the interior of the pressure vessel and adapted to change a direction of gas flow within the vessel.

Holmes, Michael Jerome (Thompson, ND); Ohrn, Theodore R. (Alliance, OH); Chen, Christopher Ming-Poh (Allentown, PA)

2010-02-09T23:59:59.000Z

118

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

SciTech Connect (OSTI)

During this quarter work was continued on characterizing the stability of layered composite membranes under a variety of conditions. Membrane permeation was tested up to 100 hours at constant pressure, temperature, and flow rates. In addition, design parameters were completed for a scale-up hydrogen separation demonstration unit. Evaluation of microstructure and effect of hydrogen exposure on BCY/Ni cermet mechanical properties was initiated. The fabrication of new cermets containing high permeability metals is reported and progress in the preparation of sulfur resistant catalysts is discussed. Finally, a report entitled ''Criteria for Incorporating Eltron's Hydrogen Separation Membranes into Vision 21 IGCC Systems and FutureGen Plants'' was completed.

Carl R. Evenson; Anthony F. Sammells; Richard T. Treglio; Jim Fisher; U. Balachandran; Richard N. Kleiner; James E. Stephan; Frank E. Anderson; Chandra Ratnasamy; Mahendra Sunkara; Jyothish Thangla; Clive Brereton; Warren Wolfs; James Lockhart

2005-01-28T23:59:59.000Z

119

Advanced biomolecular materials based on membrane-protein/polymer complexation  

SciTech Connect (OSTI)

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goal of this project was to apply neutron reflectometry and atomic force microscopy to the study of lipid membranes containing proteins. Standard sample preparation techniques were used to produce thin films of these materials appropriate for these techniques. However, these films were not stable, and a new sample preparation technique was required. Toward this goal, the authors have developed a new capability to produce large, freely suspended films of lipid multi-bilayers appropriate for these studies. This system includes a controlled temperature/humidity oven in which the films 5-cm x 5-cm are remotely drawn. The first neutron scattering experiments were then performed using this oven.

Smith, G.S.; Nowak, A. [Los Alamos National Lab., NM (United States); Safinya, C. [Univ. of California, Santa Barbara, CA (United States)

1998-12-01T23:59:59.000Z

120

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

SciTech Connect (OSTI)

Eltron Research Inc., and team members, are developing an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. This project was motivated by the National Energy Technology Laboratory (NETL) Vision 21 initiative which seeks to economically eliminate environmental concerns associated with the use of fossil fuels. This objective is being pursued using dense membranes based in part on Eltron-patented ceramic materials with a demonstrated ability for proton and electron conduction. The technical goals are being addressed by modifying single-phase and composite membrane composition and microstructure to maximize proton and electron conductivity without loss of material stability. Ultimately, these materials must enable hydrogen separation at practical rates under ambient and high-pressure conditions, without deactivation in the presence of feedstream components such as carbon dioxide, water, and sulfur. During this quarter, it was demonstrated that increasing the transition metal loading in a model perovskite composition resulted in an increase in hydrogen flux. Improved flux corresponded to the emergence of additional phases in the ceramic membrane, and highest flux was achieved for a composite consisting of pseudo-cubic and rhombohedral perovskite phases. A 0.9-mm thick membrane of this material generated a hydrogen flux in excess of 0.1 mL/min/cm{sup 2}, which was approximately 35 times greater than analogs with lower transition metal levels. The dopant level and crystal structure also correlated with membrane density and coefficient of thermal expansion, but did not appear to affect grain size or shape. Additionally, preliminary ceramic-metal (cermet) composite membranes demonstrated a 10-fold increase in flux relative to analogous membranes composed of only the ceramic component. The hydrogen flux for these cermet samples corresponded to a conductivity of {approx} 10{sup -3} S/cm, which was consistent with the predicted proton conductivity of the ceramic phase. Increasing the sweep gas flow rate in test reactors was found to significantly increase hydrogen flux, as well as apparent material conductivity for all samples tested. Adding humidity to the feed gas stream produced a small increase in hydrogen flux. However, the catalyst on ceramic membrane surfaces did not affect flux, which suggested that the process was membrane-diffusion limited. Representative samples and fabrication processes were evaluated on the basis of manufacturing practicality. it was determined that optimum membrane densification occurs over a very narrow temperature range for the subject ceramics. Additionally, calcination temperatures currently employed result in powders that are difficult mill and screen. These issues must be addressed to improve large-scale fabricability.

Shane E. Roark; Tony F. Sammells; Adam E. Calihman; Lyrik Y. Pitzman; Pamela M. Van Calcar; Richard A. Mackay; Tom F. Barton; Sara L. Rolfe; Richard N. Kleiner; James E. Stephan; Tim R. Armstrong; Mike J. Holmes; Aaron L. Wagner

2001-04-30T23:59:59.000Z

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


121

Transport Modeling of Membrane Extraction of Chlorinated Hydrocarbon from Water for Ion Mobility Spectrometry  

SciTech Connect (OSTI)

Membrane-extraction Ion Mobility Spectrometry (ME-IMS) is a feasible technique for the continuous monitoring of chlorinated hydrocarbons in water. This work studies theoretically the time-dependent characteristics of sampling and detection of trichloroethylene (TCE). The sampling is configured so that aqueous contaminants permeate through a hollow polydimethylsiloxane (PDMS) membrane and are carried away by a transport gas flowing through the membrane tube into IMS analyzer. The theoretical study is based on a two-dimensional transient fluid flow and mass transport model. The model describes the TCE mixing in the water, permeation through the membrane layer, and convective diffusion in the air flow inside membrane tube. The effect of various transport gas flow rates on temporal profiles of IMS signal intensity is investigated. The results show that fast time response and high transport yield can be achieved for ME-IMS by controlling the flow rate in the extraction membrane tube. These modeled time-response profiles are important for determining duty cycles of field-deployable sensors for monitoring chlorinated hydrocarbons in water.

Zhang, Wei [ORNL; Du, Yongzhai [ORNL; Feng, Zhili [ORNL; Xu, Jun [ORNL

2010-01-01T23:59:59.000Z

122

Transport of Gases in Carbon Molecular Sieve Membranes by Multinuclear...  

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

"difficult" separations of gas mixtures such as carbon dioxide methane and ethane ethylene separations. While there are many reports on macroscopic transport properties of CMS...

123

A Complete Transport Validated Model on a Zeolite Membrane for Carbon Dioxide Permeance and Capture  

E-Print Network [OSTI]

The CO2 emissions from major industries cause serious global environment problems and their mitigation is urgently needed. The use of zeolite membranes is a very efficient way in order to capture CO2 from some flue gases. The dominant transport mechanism at low temperature andor high pressure is the diffusion through the membrane. This procedure can be divided in three steps: Adsorption of the molecules of the species in the surface of the membrane, then a driving force gives a path where the species follow inside the membrane and finally the species desorbed from the surface of the membrane. The current work is aimed at developing a simulation model for the CO2 transport through a zeolite membrane and estimate the diffusion phenomenon through a very thin membrane of 150 nm in a Wicke-Kallenbach cell. The cell is cylindrical in shape with diameter of 19 mm and consists of a retentate gas chamber, a permeate gas chamber which are separated by a cylindrical zeolite membrane. This apparatus have been modeled wit...

Gkanas, Evangelos I; Stubos, Athanasios K; Makridis, Sofoklis S

2013-01-01T23:59:59.000Z

124

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

SciTech Connect (OSTI)

Eltron Research Inc., and team members CoorsTek, Sued Chemie, and Argonne National Laboratory are developing an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. This project was motivated by the National Energy Technology Laboratory (NETL) Vision 21 initiative which seeks to economically eliminate environmental concerns associated with the use of fossil fuels. This objective is being pursued using dense membranes based in part on Eltron-patented ceramic materials with a demonstrated ability for proton and electron conduction. The technical goals are being addressed by modifying composite membrane composition and microstructure to maximize hydrogen permeation without loss of material stability. Ultimately, these materials must enable hydrogen separation at practical rates under ambient and high-pressure conditions, without deactivation in the presence of feedstream components such as carbon dioxide, water, and sulfur. During this quarter, a composite metal membrane based on an inexpensive hydrogen permeable metal achieved permeation rates in excess of 25 mL/min/cm{sup 2}. Preliminary attempts to incorporate this metal into a cermet were successful, and a thick cermet membrane (0.83 mm) with 40 vol.% metal phase achieved a permeation rate of nearly 0.4 mL/min/cm{sup 2}. Increasing the metal phase content and decreasing membrane thickness should significantly increase permeation, while maintaining the benefits derived from cermets. Two-phase ceramic/ceramic composite membranes had low hydrogen permeability, likely due to interdiffusion of constituents between the phases. However, these materials did demonstrate high resistance to corrosion, and might be good candidates for other composite membranes. Temperature-programmed reduction measurements indicated that model cermet materials absorbed 2.5 times as much hydrogen than the pure ceramic analogs. This characteristic, in addition to higher electron conductivity, likely explains the relatively high permeation for these cermets. Incorporation of catalysts with ceramics and cermets increased hydrogen uptake by 800 to more than 900%. Finally, new high-pressure seals were developed for cermet membranes that maintained a pressure differential of 250 psi. This result indicated that the approach for high-pressure seal development could be adapted for a range of compositions. Other items discussed in this report include mechanical testing, new proton conducting ceramics, supported thin films, and alkane to olefin conversion.

Shane E. Roark; Anthony F. Sammells; Richard A. Mackay; Lyrik Y. Pitzman; Thomas A. Zirbel; Stewart R. Schesnack; Thomas F. Barton; Sara L. Rolfe; U. (Balu) Balachandran; Richard N. Kleiner; James E. Stephan; Frank E. Anderson; Aaron L. Wagner; Jon P. Wagner

2003-01-30T23:59:59.000Z

125

Magic angle spinning NMR applied to membrane protein 2D crystals : the structure and function of VDAC  

E-Print Network [OSTI]

Membrane proteins mediate critical functions in biological systems and are important drug targets for a number of diseases. Determining the three-dimensional structure and function of membrane proteins under physologically ...

Eddy, Matthew T. (Matthew Thomas)

2012-01-01T23:59:59.000Z

126

Structure and function of the Influenza membrane protein M2 by magic angle spinning NMR and dynamic nuclear polarization  

E-Print Network [OSTI]

Determination of the 3D structure of membrane proteins is a frontier that is rapidly being explored due to the importance of membrane proteins in regulating cellular processes and because they are the target of many drugs. ...

Andreas, Loren B

2014-01-01T23:59:59.000Z

127

Pinkbar is an epithelial-specific BAR domain protein that generates planar membrane structures  

SciTech Connect (OSTI)

Bin/amphipysin/Rvs (BAR)-domain proteins sculpt cellular membranes and have key roles in processes such as endocytosis, cell motility and morphogenesis. BAR domains are divided into three subfamilies: BAR- and F-BAR-domain proteins generate positive membrane curvature and stabilize cellular invaginations, whereas I-BAR-domain proteins induce negative curvature and stabilize protrusions. We show that a previously uncharacterized member of the I-BAR subfamily, Pinkbar, is specifically expressed in intestinal epithelial cells, where it localizes to Rab13-positive vesicles and to the plasma membrane at intercellular junctions. Notably, the BAR domain of Pinkbar does not induce membrane tubulation but promotes the formation of planar membrane sheets. Structural and mutagenesis analyses reveal that the BAR domain of Pinkbar has a relatively flat lipid-binding interface and that it assembles into sheet-like oligomers in crystals and in solution, which may explain its unique membrane-deforming activity.

Pyklinen, Anette; Boczkowska, Malgorzata; Zhao, Hongxia; Saarikangas, Juha; Rebowski, Grzegorz; Jansen, Maurice; Hakanen, Janne; Koskela, Essi V.; Pernen, Johan; Vihinen, Helena; Jokitalo, Eija; Salminen, Marjo; Ikonen, Elina; Dominguez, Roberto; Lappalainen, Pekka (Helsinki); (Penn)

2013-05-29T23:59:59.000Z

128

Advanced Hydrogen Transport Membranes for Vision 21 Fossil Fuel Plants  

SciTech Connect (OSTI)

During this quarter of the no cost extension a cermet composition referred to as EC101 containing a high permeability metal and a ceramic phase was prepared for sealing and permeability testing. Several different types of seals were developed and tested. In addition membrane surface stability was characterized.

Carl R. Evenson; Richard N. Kleiner; James E. Stephan; Frank E. Anderson

2006-01-31T23:59:59.000Z

129

NETL: Gasification - Recovery Act: Scale-Up of Hydrogen Transport Membranes  

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

Recovery Act: Scale-Up of Hydrogen Transport Membranes for IGCC and FutureGen Plants Recovery Act: Scale-Up of Hydrogen Transport Membranes for IGCC and FutureGen Plants Eltron Research & Development Inc. Project Number: FC26-05NT42469 Project Description The Eltron Hydrogen Transport Membrane (HTM) technology uses composite metal alloy materials to separate H2 from coal-derived syngas (a mixture of H2, CO, CO2, and steam). Carbon dioxide on the feed side of the membrane remains at high pressure and in a concentrated form suitable for capture and re-use or storage. The Eltron HTM system is an enabling technology for the production of high purity H2 and the capture of CO2 at high pressure that is applicable to future integrated gasification combined cycle (IGCC) and central station H2 production plants. These novel membranes have an operating temperature of 280 to 440 degrees Celsius (°C), which is well-matched with emerging coal gas cleaning technologies and has the potential to significantly improve the overall efficiency and process economics for future gasification-based power, fuels, and chemical production plants. Eltron's membranes can withstand differential pressures of up to 1,000 pounds per square inch gauge (psig) without structural failure, allowing for successful integration into advanced, high-pressure coal gasification plants.

130

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

SciTech Connect (OSTI)

Eltron Research Inc., and team members CoorsTek, McDermott Technology, inc., Sued Chemie, Argonne National Laboratory, and Oak Ridge National Laboratory are developing an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. This project was motivated by the National Energy Technology Laboratory (NETL) Vision 21 initiative which seeks to economically eliminate environmental concerns associated with the use of fossil fuels. This objective is being pursued using dense membranes based in part on Eltron-patented ceramic materials with a demonstrated ability for proton and electron conduction. The technical goals are being addressed by modifying single-phase and composite membrane composition and microstructure to maximize proton and electron conductivity without loss of material stability. Ultimately, these materials must enable hydrogen separation at practical rates under ambient and high-pressure conditions, without deactivation in the presence of feedstream components such as carbon dioxide, water, and sulfur.

Shane E. Roark; Anthony F. Sammells; Richard A. Mackay; Lyrik Y. Pitzman; Thomas A. Zirbel; Thomas F. Barton; Sara L. Rolfe; U. (Balu) Balachandran; Richard N. Kleiner; James E. Stephan; Frank E. Anderson; George Farthing; Dan Rowley; Tim R. Armstrong; R.D. Carneim; P.F. Becher; C-H. Hsueh; Aaron L. Wagner; Jon P. Wagner

2002-04-30T23:59:59.000Z

131

Conformational dynamics of interleukin-1beta and protein- membrane interactions  

E-Print Network [OSTI]

et al. (1995). "Protein folding intermediates: native-statethe equilibrium protein folding pathway: structure-basedEnglander, S. W. (2000). "Protein folding intermediates and

Anderson, William David

2007-01-01T23:59:59.000Z

132

The RCK Domain of the KtrAB K+ Transporter: Multiple Conformations  

E-Print Network [OSTI]

that is propagated to the membrane-bound protein, leading to ion transport (Jiang et al., 2002a; Roosild et al., 2002 transporter is a complex of the KtrB membrane protein and KtrA, an RCK do- main. RCK domains regulate eukaryotic and prokaryotic membrane proteins involved in K+ transport. Conflicting functional models have

Gruner, Sol M.

133

Charge transport in purple membrane monolayers: A sequential tunneling approach  

E-Print Network [OSTI]

Current voltage (I-V) characteristics in proteins can be sensitive to conformational change induced by an external stimulus (photon, odour, etc.). This sensitivity can be used in medical and industrial applications besides shedding new light in the microscopic structure of biological materials. Here, we show that a sequential tunneling model of carrier transfer between neighbouring amino-acids in a single protein can be the basic mechanism responsible of the electrical properties measured in a wide range of applied potentials. We also show that such a strict correlation between the protein structure and the electrical response can lead to a new generation of nanobiosensors that mimic the sensorial activity of living species. To demonstrate the potential usefulness of protein electrical properties, we provide a microscopic interpretation of recent I-V experiments carried out in bacteriorhodopsin at a nanoscale length.

Eleonora Alfinito; Jean-Francois Millithaler; Lino Reggiani

2011-05-04T23:59:59.000Z

134

Advanced Hydrogen Transport Membranes for Vision 21 Fossil Fuel Plants  

SciTech Connect (OSTI)

Eltron Research Inc. and team members CoorsTek, Sued Chemie, Argonne National Laboratory, and NORAM are developing an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. This project was motivated by the National Energy Technology Laboratory (NETL) Vision 21 initiative, which seeks to economically eliminate environmental concerns associated with the use of fossil fuels. Currently, this project is focusing on four basic categories of dense membranes: (1) mixed conducting ceramic/ceramic composites, (2) mixed conducting ceramic/metal (cermet) composites, (3) cermets with hydrogen permeable metals, and (4) layered composites containing hydrogen permeable alloys. Ultimately, these materials must enable hydrogen separation at practical rates under ambient and high-pressure conditions, without deactivation in the presence of feedstream components such as carbon dioxide, water, and sulfur. During this final quarter of the no cost extension several planar membranes of a cermet composition referred to as EC101 containing a high permeability metal and a ceramic phase were prepared and permeability testing was performed.

Carl R. Evenson; Richard N. Kleiner; James E. Stephan; Frank E. Anderson

2006-04-30T23:59:59.000Z

135

Bioenergetics and mechanical actuation analysis with membrane transport experiments for use in biomimetic  

E-Print Network [OSTI]

Bioenergetics and mechanical actuation analysis with membrane transport experiments for use considers the mechanics and bioenergetics of a prototype nastic structure system consisting of an array by the hydrolysis of adenosine triphosphate. After reviewing the biochemistry and bioenergetics of the active

Giurgiutiu, Victor

136

Thorium ions transport across Tri-n-butyl phosphate-benzene based supported liquid membranes  

SciTech Connect (OSTI)

Transport of Th(IV) ions across tri-n-butyl phosphate (TBP) benzene based liquid membranes supported in microporous hydrophobic polypropylene film (MHPF) has been studied. Various parameters such as variation of nitric acid concentration in the feed, TBP concentration in the membrane, and temperature on the given metal ions transport have been investigated. The effects of nitric acid and TBP concentrations on the distribution coefficient were also studied, and the data obtained were used to determine the Th ions-TBP complex diffusion coefficient in the membrane. Permeability coefficients of Th(IV) ions were also determined as a function of the TBP and nitric acid concentrations. The optimal conditions for the transport of Th(IV) ions across the membrane are 6 mol{sm_bullet}dm{sup -3} HNO{sub 3} concentration, 2.188 mol {center_dot} dm{sup -3} TBP concentration, and 25{degrees}C. The stoichiometry of the chemical species involved in chemical reaction during the transport of Th(IV) ions has also been studied.

Rasul, G.; Chaudry, M.A. [Pakistan Institute of Nuclear Chemistry, Islamabad (Pakistan); Afzal, M. [Quaid-I-Azam Univ., Islamabad (Pakistan)

1995-12-01T23:59:59.000Z

137

Cathode and electrolyte materials for solid oxide fuel cells and ion transport membranes  

DOE Patents [OSTI]

Novel cathode, electrolyte and oxygen separation materials are disclosed that operate at intermediate temperatures for use in solid oxide fuel cells and ion transport membranes based on oxides with perovskite related structures and an ordered arrangement of A site cations. The materials have significantly faster oxygen kinetics than in corresponding disordered perovskites.

Jacobson, Allan J; Wang, Shuangyan; Kim, Gun Tae

2014-01-28T23:59:59.000Z

138

Transport Properties and Performance of Polymer Electrolyte Membranes for the Hybrid Sulfur Electrolyzer  

E-Print Network [OSTI]

not consume fossil fuels or pro- duce CO2 while producing highly pure hydrogen.1-10 Gaseous SO2 fedTransport Properties and Performance of Polymer Electrolyte Membranes for the Hybrid Sulfur and Biological Systems Department, Albuquerque, New Mexico 87123, USA c Department of Materials Science

Weidner, John W.

139

Distributed Reforming of Renewable Liquids via Water Splitting using Oxygen Transport Membrane (OTM) (Presentation)  

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

Reforming of Renewable Reforming of Renewable Liquids via Water Splitting using Oxygen Transport Membrane (OTM) * U. (Balu) Balachandran, T. H. Lee, C. Y. Park, and S. E. Dorris Energy Systems Division E-mail: balu@anl.gov * Work supported by the Hydrogen, Fuel Cells, and Infrastructure Technologies Program of DOE's Office of Energy Efficiency and Renewable Energy Presented at the Bio-derived Liquids Working Group (BILIWG) Meeting, Nov. 6, 2007. BILIWG Meeting, Nov. 6, 2007 2 Objective & Rationale Objective: Develop compact dense ceramic membrane reactors that enable the efficient and cost-effective production of hydrogen by reforming renewable liquid fuels using pure oxygen produced by water splitting and transported by an OTM. Rationale: Membrane technology provides the means to attack barriers to the

140

Correlating Humidity-Dependent Ionically Conductive Surface Area with Transport Phenomena in Proton-Exchange Membranes  

SciTech Connect (OSTI)

The objective of this effort was to correlate the local surface ionic conductance of a Nafion? 212 proton-exchange membrane with its bulk and interfacial transport properties as a function of water content. Both macroscopic and microscopic proton conductivities were investigated at different relative humidity levels, using electrochemical impedance spectroscopy and current-sensing atomic force microscopy (CSAFM). We were able to identify small ion-conducting domains that grew with humidity at the surface of the membrane. Numerical analysis of the surface ionic conductance images recorded at various relative humidity levels helped determine the fractional area of ion-conducting active sites. A simple square-root relationship between the fractional conducting area and observed interfacial mass-transport resistance was established. Furthermore, the relationship between the bulk ionic conductivity and surface ionic conductance pattern of the Nafion? membrane was examined.

He, Qinggang; Kusoglu, Ahmet; Lucas, Ivan T.; Clark, Kyle; Weber, Adam Z.; Kostecki, Robert

2011-08-01T23:59:59.000Z

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


141

Membrane protein kit may lead to better targeted drugs | Argonne National  

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

Argonne biologists Deborah Hanson and Phil Laible developed a kit that enables its users to easily generate large amounts of membrane proteins. To view a larger version of the image, click on it. Argonne biologists Deborah Hanson and Phil Laible developed a kit that enables its users to easily generate large amounts of membrane proteins. To view a larger version of the image, click on it. Argonne biologists Deborah Hanson and Phil Laible developed a kit that enables its users to easily generate large amounts of membrane proteins. To view a larger version of the image, click on it. Filamentous cells of the bacterium Rhodobacter sphaeroides. Argonne scientists received an R&D100 Award for using Rhodobacter to develop a new system for growing membrane proteins used in drug discovery research. Image by Sheng-Wen Chui, University of Oxford. To view a larger version of the image, click on it. Filamentous cells of the bacterium Rhodobacter sphaeroides. Argonne

142

Trafficking of integral membrane proteins of the inner nuclear membrane can be mediated by the ''sorting motif'' of autographa californica nucleopolyhedrovirus odv-e66  

E-Print Network [OSTI]

The amino-terminal 33 amino acids of the baculovirus integral membrane protein, ODV-E66, are sufficient for localization of fusion proteins to viralinduced intranuclear microvesicles (MV) and occlusion derived virus envelopes during infection...

Williamson, Shawn T

2006-10-30T23:59:59.000Z

143

Simulation of Membrane and Cell Culture Permeability and Transport  

E-Print Network [OSTI]

for neutral and ionized species partitioning into the membrane - only non-ionized species. Donor bulk (D) Acceptor bulk (A) D w h w D w h w k i c N k o c N ?? = ? = ?+?? ? + ? + = == i 1p pKa-pHpj 1r pH1)r(jpKa Ux N x p 1s a s j rs b s 10101 1 cc c..., Kansas, 2006 Pgp expression in human SI Mouly, S., Paine, M.F. PharmRes-20(10):1595-1598 (2003) GPEN, Kansas, 2006 Talinolol Non-linear Dose Dependence Talinolol Dose Dependence de Mey et al. J. Cardio. Pharmacol. 26(6):879 (1995) 0 200 400 600 800 1000...

Bolger, Michael

2006-10-26T23:59:59.000Z

144

E-Print Network 3.0 - abc transporter mutants Sample Search Results  

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

THE ABC TRANSPORTER SUPERFAMILY Summary: -association of point mutants. 1. Introduction ATP-binding cassette (ABC) transporters are membrane-spanning proteins... -associated...

145

Synthesizing Membrane Proteins Using In Vitro Methodology | Argonne...  

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

Proteins Using In Vitro Methodology Technology available for licensing: in vitro, cell-free expression system that caters to the production of protein types that are challenging...

146

Quantitative description of ion transport via plasma membrane of yeast and small cells  

E-Print Network [OSTI]

Modelling of ion transport via plasma membrane needs identification and quantitative understanding of the involved processes. Brief characterisation of ion transport systems of a yeast cell (Pma1, Ena1, TOK1, Nha1, Trk1, Trk2, non-selective cation conductance) and estimates concerning the number of molecules of each transporter per a cell allow predicting the corresponding ion flows. Comparison of ion transport in small yeast cell and several animal cell types is provided and importance of cell volume to surface ratio is stressed. Role of cell wall and lipid rafts is discussed in aspect of required increase in spatial and temporary resolution of measurements. Conclusions are formulated to describe specific features of ion transport in a yeast cell. Potential directions of future research are outlined based on the assumptions.

Volkov, Vadim

2012-01-01T23:59:59.000Z

147

Quantitative description of ion transport via plasma membrane of yeast and small cells  

E-Print Network [OSTI]

Modelling of ion transport via plasma membrane needs identification and quantitative understanding of the involved processes. Brief characterisation of ion transport systems of a yeast cell (Pma1, Ena1, TOK1, Nha1, Trk1, Trk2, non-selective cation conductance) and estimates concerning the number of molecules of each transporter per a cell allow predicting the corresponding ion flows. Comparison of ion transport in small yeast cell and several animal cell types is provided and importance of cell volume to surface ratio is stressed. Role of cell wall and lipid rafts is discussed in aspect of required increase in spatial and temporary resolution of measurements. Conclusions are formulated to describe specific features of ion transport in a yeast cell. Potential directions of future research are outlined based on the assumptions.

Vadim Volkov

2012-12-18T23:59:59.000Z

148

High-Order Membrane Complexes from Activated G-Protein Subunits  

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

High-Order Membrane Complexes from Activated G-Protein Subunits Print High-Order Membrane Complexes from Activated G-Protein Subunits Print Many physiological processes initiated in response to external (extracellular) signals such as hormones, neurotransmitters, or light are regulated by a complex dance involving GTP-binding (G) proteins: G-protein-coupled receptors (GPCRs), proteins integral to the cell membrane, sense the signal and activate G proteins in the cellular cytoplasm, but enzymes such as G-protein-coupled receptor kinase 2 (GRK2) inhibit the activity of the G proteins. A joint University of Michigan-University of Illinois, Chicago, team has determined the first structure of a particular G-protein-GRK2 complex. The structure in combination with previous structures of related G-protein complexes shows how Nature has evolved the G-protein structure to not only propagate activation signals but at the same time also directly respond to regulatory proteins that control the duration of the signal.

149

High-Order Membrane Complexes from Activated G-Protein Subunits  

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

High-Order Membrane Complexes from Activated G-Protein Subunits Print High-Order Membrane Complexes from Activated G-Protein Subunits Print Many physiological processes initiated in response to external (extracellular) signals such as hormones, neurotransmitters, or light are regulated by a complex dance involving GTP-binding (G) proteins: G-protein-coupled receptors (GPCRs), proteins integral to the cell membrane, sense the signal and activate G proteins in the cellular cytoplasm, but enzymes such as G-protein-coupled receptor kinase 2 (GRK2) inhibit the activity of the G proteins. A joint University of Michigan-University of Illinois, Chicago, team has determined the first structure of a particular G-protein-GRK2 complex. The structure in combination with previous structures of related G-protein complexes shows how Nature has evolved the G-protein structure to not only propagate activation signals but at the same time also directly respond to regulatory proteins that control the duration of the signal.

150

Transport of trivalent and hexavalent chromium through different ion-selective membranes in acidic aqueous media  

SciTech Connect (OSTI)

The aim of this work was to evaluate the transport of trivalent and hexavalent chromium through anion- and cation-selective membranes using two- and three-compartment electrodialysis cells. Tests were done with acidic solutions of trivalent chromium ions, Cr{sup 3+}, and hexavalent chromium ions, Cr{sub 2}O{sub 7}{sup 2{minus}}. In each situation the transport of metallic ions through the membrane was evaluated. In the tests with trivalent chromium, Nafion 417 and Selemion CMT cation-selective membranes were used, and in the tests with hexavalent chromium, Selemion AMT membrane was used. The influence of SO{sub 4}{sup 2{minus}} ions and of the concentration of H{sup +} ions in the solutions was also analyzed. Results showed the oxidation of the Cr{sup 3+} ion at the anode and the reduction of the Cr{sub 2}O{sub 7}{sup 2{minus}} ion at the cathode. The maximum yield in the process was reached when hexavalent chromium solutions were used in the absence of sulfate ions and a Selemion AMT membrane in a three-compartment cell.

Costa, R.F.D.; Rodrigues, M.A.S.; Ferreira, J.Z. [LACOR-PPGEM-UFRGS, Porto Alegre (Brazil)

1998-06-01T23:59:59.000Z

151

Transport of copper ammines through a cation-exchange membrane during electrodialysis  

SciTech Connect (OSTI)

Extraction of copper ammine complexes from waste waters in electroplating technology and in production of cuprammonium fibers is an important problem and electrodialysis with ion-exchange membranes is the most promising method of solving it. The authors aim was to study transport of copper(II) ammines through a commercial cation-exchange membrane of the MK-40 type. The electrodialyzer consisted of five Plexiglas compartments separated in alternating order by MK-40 cation-exchange and MA-40 anion-exchange membranes. The authors studied the dependence of the transport of copper(II) ammine complexes on the current density at copper concentration 0.025 M in the desalination compartment and 0.15 M ammonia concentration. The experiments lead to the conclusion that electrodialysis of copper(II) ammine complexes is possible only at current densities below the limiting values and that the transport is accompanied by decrease of the formation function of the complexes both in the membrane and in the solution of the concentrate receiving compartment.

Kireeva, L.D.; Shaposhnik, V.A.; Sorokina, V.I.

1987-09-10T23:59:59.000Z

152

Directed transport as a mechanism for protein folding in vivo  

E-Print Network [OSTI]

We propose a model for protein folding in vivo based on a Brownian-ratchet mechanism in the multidimensional energy landscape space. The device is able to produce directed transport taking advantage of the assumed intrinsic asymmetric properties of the proteins and employing the consumption of energy provided by an external source. Through such a directed transport phenomenon, the polypeptide finds the native state starting from any initial state in the energy landscape with great efficacy and robustness, even in the presence of different type of obstacles. This model solves Levinthal's paradox without requiring biased transition probabilities but at the expense of opening the system to an external field.

Ernesto Gonzalez-Candela; Victor Romero-Rochin

2009-09-23T23:59:59.000Z

153

Molecular Basis for Nanoscopic Membrane Curvature Generation from Quantum Mechanical Models and Synthetic Transporter  

E-Print Network [OSTI]

that an arginine-rich, 11AA sequence from the transactivator of transcription (TAT) protein of HIV, YGRKKRRQRRR (CPP) such as the TAT peptide can efficiently translocate across cellular membranes.1-6 Many types, now referred to as the TAT peptide, is sufficient for cellular uptake. It was soon realized by Wender

Tew, Gregory N.

154

Catalyzed CO.sub.2-transport membrane on high surface area inorganic support  

DOE Patents [OSTI]

Disclosed are membranes and methods for making the same, which membranes provide improved permeability, stability, and cost-effective manufacturability, for separating CO.sub.2 from gas streams such as flue gas streams. High CO.sub.2 permeation flux is achieved by immobilizing an ultra-thin, optionally catalyzed fluid layer onto a meso-porous modification layer on a thin, porous inorganic substrate such as a porous metallic substrate. The CO.sub.2-selective liquid fluid blocks non-selective pores, and allows for selective absorption of CO.sub.2 from gas mixtures such as flue gas mixtures and subsequent transport to the permeation side of the membrane. Carbon dioxide permeance levels are in the order of 1.0.times.10.sup.-6 mol/(m.sup.2sPa) or better. Methods for making such membranes allow commercial scale membrane manufacturing at highly cost-effective rates when compared to conventional commercial-scale CO.sub.2 separation processes and equipment for the same and such membranes are operable on an industrial use scale.

Liu, Wei

2014-05-06T23:59:59.000Z

155

NETL: Gasification - Development of Ion-Transport Membrane Oxygen  

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

Program Background and Project Benefits Program Background and Project Benefits Gasification is used to convert a solid feedstock, such as coal, petcoke, or biomass, into a gaseous form, referred to as synthesis gas or syngas, which is primarily hydrogen and carbon monoxide. With gasification-based technologies, pollutants can be captured and disposed of or converted to useful products. Gasification can generate clean power by adding steam to the syngas in a water-gas-shift reactor to convert the carbon monoxide to carbon dioxide (CO2) and to produce additional hydrogen. The hydrogen and CO2 are separated-the hydrogen is used to make power and the CO2 is sent to storage, converted to useful products or used for EOR. In addition to efficiently producing electric power, a wide range of transportation fuels and chemicals can be produced from the cleaned syngas, thereby providing the flexibility needed to capitalize on the changing economic market. As a result, gasification provides a flexible technology option for using domestically available resources while meeting future environmental emission standards. Polygeneration plants that produce multiple products are uniquely possible with gasification technologies. The Gasification Systems program is developing technologies in three key areas to reduce the cost and increase the efficiency of producing syngas: (1) Feed Systems, (2) Gasifier Optimization and Plant Supporting Systems, and (3) Syngas Processing Systems.

156

Disordered Proteins: Biological Membranes as Two-Dimensional Aggregation Matrices  

Science Journals Connector (OSTI)

Aberrant folded proteins and peptides are hallmarks of amyloidogenic diseases. However, the molecular processes that cause these proteins to adopt non-native structures in vivo and become cytotoxic are still l...

Roberth Bystrm; Christopher Aisenbrey; Tomasz Borowik

2008-11-01T23:59:59.000Z

157

Transport Membrane Condenser for Water and Energy Recovery from Power Plant Flue Gas  

SciTech Connect (OSTI)

The new waste heat and water recovery technology based on a nanoporous ceramic membrane vapor separation mechanism has been developed for power plant flue gas application. The recovered water vapor and its latent heat from the flue gas can increase the power plant boiler efficiency and reduce water consumption. This report describes the development of the Transport Membrane Condenser (TMC) technology in details for power plant flue gas application. The two-stage TMC design can achieve maximum heat and water recovery based on practical power plant flue gas and cooling water stream conditions. And the report includes: Two-stage TMC water and heat recovery system design based on potential host power plant coal fired flue gas conditions; Membrane performance optimization process based on the flue gas conditions, heat sink conditions, and water and heat transport rate requirement; Pilot-Scale Unit design, fabrication and performance validation test results. Laboratory test results showed the TMC system can exact significant amount of vapor and heat from the flue gases. The recovered water has been tested and proved of good quality, and the impact of SO{sub 2} in the flue gas on the membrane has been evaluated. The TMC pilot-scale system has been field tested with a slip stream of flue gas in a power plant to prove its long term real world operation performance. A TMC scale-up design approach has been investigated and an economic analysis of applying the technology has been performed.

Dexin Wang

2012-03-31T23:59:59.000Z

158

Correlation of Structural Differences between Nafion/Polyaniline and Nafion/Polypyrrole Composite Membranes and Observed Transport Properties  

SciTech Connect (OSTI)

Polyaniline/Nafion and polypyrrole/Nafion composite membranes, prepared by chemical polymerization, are studied by infrared and nuclear magnetic resonance spectroscopy, and scanning electron microscopy. Differences in vanadium ion diffusion through the membranes and in the membranes area specific resistance are linked to analytical observations that polyaniline and polypyrrole interact differently with Nafion. Polypyrrole, a weakly basic polymer, binds less strongly to the sulfonic acid groups of the Nafion membrane, and thus the hydrophobic polymer aggregates in the center of the Nafion channel rather than on the hydrophilic side chains of Nafion that contain sulfonic acid groups. This results in a drastically elevated membrane resistance and an only slightly decreased vanadium ion permeation compared to a Nafion membrane. Polyaniline on the other hand is a strongly basic polymer, which forms along the sidewalls of the Nafion pores and on the membrane surface, binding tightly to the sulfonic acid groups of Nafion. This leads to a more effective reduction in vanadium ion transport across the polyaniline/Nafion membranes and the increase in membrane resistance is less severe. The performance of selected polypyrrole/Nafion composite membranes is tested in a static vanadium redox cell. Increased coulombic efficiency, compared to a cell employing Nafion, further confirms the reduced vanadium ion transport through the composite membranes.

Schwenzer, Birgit; Kim, Soowhan; Vijayakumar, M.; Yang, Zhenguo; Liu, Jun

2011-04-15T23:59:59.000Z

159

Dynamics of a vesicle as a cell mimic: Effects of interior structure, cross-membrane transport, and interaction with filaments  

E-Print Network [OSTI]

Dynamics of a vesicle as a cell mimic: Effects of interior structure, cross-membrane transport, and interaction with filaments The biological membrane is, in essence, a thermodynamically-nonequilibrium lipid bilayer [6, 30, 34, 43, 47] with a variety of molecular motors, ion pumps, or channels residing within [19

Young, Yuan N.

160

Biological Detergents Guide for solubilization of membrane proteins  

E-Print Network [OSTI]

, but their solu- bilization and purification is more challenging because most of these proteins are present hydrophobic carbon chain at the other end. The polar group forms hydrogen bonds with water molecules, while be affected by other components of the biological system, such as lipids, proteins, pH, ionic strength

Lebendiker, Mario

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


161

Application of various membranes to remove NOM typically occurring in Korea with respect to DBP, AOC and transport parameters  

Science Journals Connector (OSTI)

Bench- and pilot-scale membrane tests were performed to remove natural organic matter (NOM) originating from Paldang Lake in Korea. Membrane performance was demonstrated in terms of DOC, biodegradable organic carbon (BDOC), assimilable organic carbon (AOC), and transport parameters. Various membranes such as reverse osmosis (RO), nanofiltration (NF) and ultrafiltration (UF) were investigated for this study. Four different NF membranes were selected for pilot-scale filtration testing and investigated in terms of both flux decline and DOC removal. To demonstrate the effect of temperature on the source water seasonally, the flux of membranes was measured with pure water at different temperatures ranging from 25 to 7C. Coagulation/sedimentation treated water was used as feed water without removing residual chlorine; related plants were located at the Suji water treatment plant of Yongin City. To investigate more rigorously the organic fouling for various NF membranes, mass transport behaviors of organic matter solutes were evaluated by an irreversible thermodynamic model. The pore sizes of the NF membranes tested in the pilot slightly increased due to the oxidation of the polymer structure of the membranes from residual chlorine during the 4-month tests. Periodic chemical cleaning with a caustic solution was made to prevent accumulation of foulants on the membrane surface. The NF membranes exhibited stable efficiencies in terms of DOC and AOC removal during the test for 4 months.

Noeon Park; Boksoon Kwon; Minjeong Sun; Hyowon Ahn; Chunghwan Kim; Changho Kwoak; Dongju Lee; Seonha Chae; Hoon Hyung; Jaeweon Cho

2005-01-01T23:59:59.000Z

162

Mathematical modeling of liquid/liquid hollow fiber membrane contactor accounting for interfacial transport phenomena: Extraction of lanthanides as a surrogate for actinides  

SciTech Connect (OSTI)

This report is divided into two parts. The second part is divided into the following sections: experimental protocol; modeling the hollow fiber extractor using film theory; Graetz model of the hollow fiber membrane process; fundamental diffusive-kinetic model; and diffusive liquid membrane device-a rigorous model. The first part is divided into: membrane and membrane process-a concept; metal extraction; kinetics of metal extraction; modeling the membrane contactor; and interfacial phenomenon-boundary conditions-applied to membrane transport.

Rogers, J.D.

1994-08-04T23:59:59.000Z

163

The Crystal Structure of OprG from Pseudomonas aeruginosa a Potential Channel for Transport of Hydrophobic Molecules across the Outer Membrane  

SciTech Connect (OSTI)

The outer membrane (OM) of Gram-negative bacteria provides a barrier to the passage of hydrophobic and hydrophilic compounds into the cell. The OM has embedded proteins that serve important functions in signal transduction and in the transport of molecules into the periplasm. The OmpW family of OM proteins, of which P. aeruginosa OprG is a member, is widespread in Gram-negative bacteria. The biological functions of OprG and other OmpW family members are still unclear. The outer membrane (OM) of Gram-negative bacteria provides a barrier to the passage of hydrophobic and hydrophilic compounds into the cell. The OM has embedded proteins that serve important functions in signal transduction and in the transport of molecules into the periplasm. The OmpW family of OM proteins, of which P. aeruginosa OprG is a member, is widespread in Gram-negative bacteria. The biological functions of OprG and other OmpW family members are still unclear. The crystal structure, together with recent biochemical data, suggests that OprG and other OmpW family members form channels that mediate the diffusion of small hydrophobic molecules across the OM by a lateral diffusion mechanism similar to that of E. coli FadL.

D Touw; D Patel; b van den Berg

2011-12-31T23:59:59.000Z

164

ccsd-00014522,version1-5Oct2006 Co-transport-induced instability of membrane voltage in tip-growing cells  

E-Print Network [OSTI]

ccsd-00014522,version1-5Oct2006 Co-transport-induced instability of membrane voltage in tip at the same time. It is shown that these co-transporters destabilize generically the membrane voltage- tive dynamics and activity of membrane ion channels. Action potential and cardiac excitation spiral

Paris-Sud XI, Université de

165

Two-phase flow and transport in the air cathode of proton exchange membrane fuel cells  

SciTech Connect (OSTI)

Two-phase flow and transport of reactants and products in the air cathode of proton exchange membrane (PEM) fuel cells is studied analytically and numerically. Four regimes of water distribution and transport are classified by defining three threshold current densities and a maximum current density. They correspond to first appearance of liquid water at the membrane/cathode interface, extension of the gas-liquid two-phase zone to the cathode/channel interface, saturated moist air exiting the gas channel, and complete consumption of oxygen by the electrochemical reaction. When the cell operates above the first threshold current density, liquid water appears and a two-phase zone forms within the porous cathode. A two-phase, multi-component mixture model in conjunction with a finite-volume-based computational fluid dynamics (CFD) technique is applied to simulate the cathode operation in this regime. The model is able to handle the situation where a single-phase region co-exists with a two-phase zone in the air cathode. For the first time, the polarization curve as well as water and oxygen concentration distributions encompassing both single- and two-phase regimes of the air cathode are presented. Capillary action is found to be the dominant mechanism for water transport inside the two-phase zone. The liquid water saturation within the cathode is predicted to reach 6.3% at 1.4 A/cm{sup 2}.

WANG,Z.H.; WANG,C.Y.; CHEN,KEN S.

2000-03-20T23:59:59.000Z

166

Ultrafiltration membrane performance when processing oilseed protein extracts  

E-Print Network [OSTI]

, 1971, pp. 81-85. Kozinski, A. A. , and Lightfoot, E . N . "Protein Ultra- filtration: A General Example of Boundary Layer Fil- tration, " AIChE Journal, Vol. 18, No. 5, 1972, pp. 1030-1040. 36 10. AOCS, "Official and Tentative Methods, " American Oil..., 1971, pp. 81-85. Kozinski, A. A. , and Lightfoot, E . N . "Protein Ultra- filtration: A General Example of Boundary Layer Fil- tration, " AIChE Journal, Vol. 18, No. 5, 1972, pp. 1030-1040. 36 10. AOCS, "Official and Tentative Methods, " American Oil...

Hensley, Donald Wayne

2012-06-07T23:59:59.000Z

167

Investigating cotranslational protein integration into the endoplasmic reticulum membrane  

E-Print Network [OSTI]

proteins, whereas, if the former, a specific TM helix surface would face TRAM and/or Sec61?. Integration intermediates were prepared by in vitro translation of truncated mRNAs in the presence of a Lys-tRNA analog with a photoreactive moiety attached...

McCormick, Peter Joseph

2005-02-17T23:59:59.000Z

168

Stealth carriers for low-resolution structure determination of membrane proteins in solution  

Science Journals Connector (OSTI)

Specifically deuterated phospholipid bilayer nanodiscs have been developed which give a minimal contribution to neutron scattering data when used in 100% D2O. These provide an optimal platform for low-resolution structural determination of membrane proteins and their complexes in solution.

Maric, S.

2014-01-29T23:59:59.000Z

169

Brain Phosphoproteome Obtained by a FASP-Based Method Reveals Plasma Membrane Protein Topology  

Science Journals Connector (OSTI)

Brain Phosphoproteome Obtained by a FASP-Based Method Reveals Plasma Membrane Protein Topology ... Taking advantage of Filter Assisted Sample Preparation (FASP) method for sample preparation, we performed an analysis of phosphorylation sites in mouse brain. ... Taking advantage of the recently developed Filter Assisted Sample Preparation (FASP) method for sample preparation, we performed an in-depth analysis of phosphorylation sites in mouse brain. ...

Jacek R. Wi?niewski; Nagarjuna Nagaraj; Alexandre Zougman; Florian Gnad; Matthias Mann

2010-04-26T23:59:59.000Z

170

A blue-light-activated GTP-binding protein in the plasma membranes of etiolated peas.  

Science Journals Connector (OSTI)

...GTP-binding protein in the plasma membranes of etiolated peas KATHERINE M. F. WARPEHA*, HEIDI E. HAMMt, MARK M. RASENICKt...Acad. Sci. USA 85, 3066-3070. 20. Rasenick, M. M., Wheeler, G. L., Bitensky, M. W., Kosack, C. & Stein, P...

K M Warpeha; H E Hamm; M M Rasenick; L S Kaufman

1991-01-01T23:59:59.000Z

171

Membrane vesicles: A simplified system for studying auxin transport. Final technical report  

SciTech Connect (OSTI)

Indoleacetic acid (IAA), the auxin responsible for regulation of growth, is transported polarly in plants. Several different models have been suggested to account for IAA transport by cells and its accumulation by membrane vesicles. One model sees diffusion of IAA driven by a pH gradient. The anion of a lipophilic weak acid like IAA or butyrate accumulates in an alkaline compartment in accord with the size of the pH gradient The accumulation of IAA may be diminished by the permeability of its lipophilic anion. This anion leak may be blocked by NPA. With anion efflux blocked, a gradient of two pH units would support an IAA accumulation of less than 50-fold at equilibrium (2) Another model sees diffusion of IAA in parallel with a saturable symport (IAA{sup {minus}} + nH{sup +}), driven by both the pH gradient and membrane voltage. Such a symport should be highly accumulative, however, with a lipophilic weak acid such as IAA, net diffusive efflux of IAAH whenever IAAHI{sub i} > IAAH{sub o} would constitute a leak. (3) A third model sees a pH change driven IAA uptake and saturable symport enhanced by internal binding sites. Following pH gradient-driven accumulation of IAA, the anion may bind to an intravesicular site, permitting further uptake of IAA. NPA, by blocking anion efflux, enhances this binding. We have reported that membrane vesicles isolated from actively growing plant tissues are a good system for studying the mechanisms involved in the transport and accumulation of auxin.

Goldsmith, M.H.M.

1989-12-31T23:59:59.000Z

172

LDRD final report on imaging self-organization of proteins in membranes by photocatalytic nano-tagging.  

SciTech Connect (OSTI)

We have developed a new nanotagging technology for detecting and imaging the self-organization of proteins and other components of membranes at nanometer resolution for the purpose of investigating cell signaling and other membrane-mediated biological processes. We used protein-, lipid-, or drug-bound porphyrin photocatalysts to grow in-situ nanometer-sized metal particles, which reveal the location of the porphyrin-labeled molecules by electron microscopy. We initially used photocatalytic nanotagging to image assembled multi-component proteins and to monitor the distribution of lipids and porphyrin labels in liposomes. For example, by exchanging the heme molecules in hemoproteins with a photocatalytic tin porphyrin, a nanoparticle was grown at each heme site of the protein. The result obtained from electron microscopy for a tagged multi-subunit protein such as hemoglobin is a symmetric constellation of a specific number of nanoparticle tags, four in the case of the hemoglobin tetramer. Methods for covalently linking photocatalytic porphyrin labels to lipids and proteins were also developed to detect and image the self-organization of lipids, protein-protein supercomplexes, and membrane-protein complexes. Procedures for making photocatalytic porphyrin-drug, porphyrin-lipid, and porphyrin-protein hybrids for non-porphyrin-binding proteins and membrane components were pursued and the first porphyrin-labeled lipids was investigated in liposomal membrane models. Our photocatalytic nanotagging technique may ultimately allow membrane self-organization and cell signaling processes to be imaged in living cells. Fluorescence and plasmonic spectra of the tagged proteins might also provide additional information about protein association and membrane organization. In addition, a porphyrin-aspirin or other NSAID hybrid may be used to grow metal nanotags for the pharmacologically important COX enzymes in membranes so that the distribution of the protein can be imaged at the nanometer scale.

Zavadil, Kevin Robert; Shelnutt, John Allen; Sasaki, Darryl Yoshio; Song, Yujiang; Medforth, Craig J.

2005-11-01T23:59:59.000Z

173

ATP-independent reversal of a membrane protein aggregate by a chloroplast SRP subunit  

SciTech Connect (OSTI)

Membrane proteins impose enormous challenges to cellular protein homeostasis during their post-translational targeting, and they require chaperones to keep them soluble and translocation competent. Here we show that a novel targeting factor in the chloroplast signal recognition particle (cpSRP), cpSRP43, is a highly specific molecular chaperone that efficiently reverses the aggregation of its substrate proteins. In contrast to 'ATPases associated with various cellular activities' (AAA{sup +}) chaperones, cpSRP43 uses specific binding interactions with its substrate to mediate its 'disaggregase' activity. This disaggregase capability can allow targeting machineries to more effectively capture their protein substrates and emphasizes a close connection between protein folding and trafficking processes. Moreover, cpSRP43 provides the first example to our knowledge of an ATP-independent disaggregase and shows that efficient reversal of protein aggregation can be attained by specific binding interactions between a chaperone and its substrate.

Jaru-Ampornpan, Peera; Shen, Kuang; Lam, Vinh Q.; Ali, Mona; Doniach, Sebastian; Jia, Tony Z.; Shan, Shu-ou (CIT); (Stanford)

2010-07-23T23:59:59.000Z

174

Ideal Desalination through Graphyne-4 Membrane: Nanopores for Quantized Water Transport  

E-Print Network [OSTI]

Graphyne-4 sheet exhibits promising potential for nanoscale desalination to achieve both high water permeability and salt rejection rate. Extensive molecular dynamics simulations on pore-size effects suggest that graphyne-4, with 4 acetylene bonds between two adjacent phenyl rings, has the best performance with 100% salt rejection and an unprecedented water permeability, to our knowledge, of ~13L/cm2/day/MPa, about 10 times higher than the state-of-the-art nanoporous graphene reported previously (Nano Lett.s 2012, 12, 3602-3608). In addition, the membrane entails very low energy consumption for producing 1m3 of fresh water, i.e., 3.6e-3 kWh/m3, three orders of magnitude less than the prevailing commercial membranes based on reverse osmosis. Water flow rate across the graphyne-4 sheet exhibits intriguing nonlinear dependence on the pore size owing to the quantized nature of water flow at the nanoscale. Such novel transport behavior has important implications to the design of highly effective and efficient desalination membranes.

Chongqin Zhu; Hui Li; Xiao Cheng Zeng; Sheng Meng

2013-06-30T23:59:59.000Z

175

Chemical crosslinking and mass spectrometry studies of the structure and dynamics of membrane proteins and receptors.  

SciTech Connect (OSTI)

Membrane proteins make up a diverse and important subset of proteins for which structural information is limited. In this study, chemical cross-linking and mass spectrometry were used to explore the structure of the G-protein-coupled photoreceptor bovine rhodopsin in the dark-state conformation. All experiments were performed in rod outer segment membranes using amino acid 'handles' in the native protein sequence and thus minimizing perturbations to the native protein structure. Cysteine and lysine residues were covalently cross-linked using commercially available reagents with a range of linker arm lengths. Following chemical digestion of cross-linked protein, cross-linked peptides were identified by accurate mass measurement using liquid chromatography-fourier transform mass spectrometry and an automated data analysis pipeline. Assignments were confirmed and, if necessary, resolved, by tandem MS. The relative reactivity of lysine residues participating in cross-links was evaluated by labeling with NHS-esters. A distinct pattern of cross-link formation within the C-terminal domain, and between loop I and the C-terminal domain, emerged. Theoretical distances based on cross-linking were compared to inter-atomic distances determined from the energy-minimized X-ray crystal structure and Monte Carlo conformational search procedures. In general, the observed cross-links can be explained by re-positioning participating side-chains without significantly altering backbone structure. One exception, between C3 16 and K325, requires backbone motion to bring the reactive atoms into sufficient proximity for cross-linking. Evidence from other studies suggests that residues around K325 for a region of high backbone mobility. These findings show that cross-linking studies can provide insight into the structural dynamics of membrane proteins in their native environment.

Haskins, William E.; Leavell, Michael D.; Lane, Pamela; Jacobsen, Richard B.; Hong, Joohee; Ayson, Marites J.; Wood, Nichole L.; Schoeniger, Joseph S.; Kruppa, Gary Hermann; Sale, Kenneth L.; Young, Malin M.; Novak, Petr

2005-03-01T23:59:59.000Z

176

Resolution Enhancement in Solid-State NMR of Oriented Membrane Proteins by Anisotropic Differential Linebroadening  

Science Journals Connector (OSTI)

(1, 2) So far, most studies have addressed smaller membrane proteins and peptides for which it has been possible to obtain well-resolved peaks in 2D separated local field (SLF) spectra correlating the amide 1H?15N dipoledipole couplings and 15N chemical shifts. ... In this Communication, we demonstrate a new method that may significantly improve the resolution in the 15N dimension of 1D 15N and 2D 1H ?15N SLF experiments for oriented membrane protein systems. ... The immediate gain of homonuclear decoupling is demonstrated in Figure 2 by simulated 2D SLF spectra for a uniformly 15N-labeled ?-helical peptide with a mosaic spread of ?? = 8 using standard heteronuclear (CW or SPINAL-64) or FSLG decoupling during acquisition. ...

Thomas Vosegaard; Kresten Bertelsen; Jan M. Pedersen; Lea Thgersen; Birgit Schitt; Emad Tajkhorshid; Troels Skrydstrup; Niels Chr. Nielsen

2008-03-15T23:59:59.000Z

177

2-Methyltetrahydrofuran and cyclopentylmethylether: Two green solvents for efficient purification of membrane proteins like FhuA  

Science Journals Connector (OSTI)

Abstract ?-Barrel shaped membrane proteins are attractive hosts for hybrid catalysts in which reactions are controlled through space. Production and extraction of ?-barrel shaped membrane proteins in gram scale is challenging due to their hydrophobicity. Solvent mixtures such as chloroform/methanol (CM) are widely used for membrane protein extraction but toxicity and mutagenicity were reported in several cases. 2-Methyltetrahydrofuran (2-MeTHF) and cyclopentylmethylether (CPME) are two green (reduction of solvent-related environmental damage in chemical production) and potentially efficient solvents for membrane protein purification. On the example of the ferric hydroxamate uptake protein component A (FhuA) a 4-Step method was developed to provide gram amounts of highly purified FhuA: cell disruption (Step 1), removal of membrane protein impurities with n-octyl-poly-oxyethylene (oPOE) (Step 2), dissolution of membranes and FhuA precipitation (Step 3), and refolding using urea and dialysis with polyethylene-polyethyleneglycol (PE-PEG; Step 4) resulted in high FhuA purity (95% 2-MeTHF, 80% CPME; 70mg FhuA per liter fermenter broth). Structural integrity of FhuA protein was confirmed by circular dichroism (CD) and a translocation functionality assay.

Stefanie-Joana Tenne; Julia Kinzel; Marcus Arlt; Fabrizio Sibilla; Marco Bocola; Ulrich Schwaneberg

2013-01-01T23:59:59.000Z

178

Transport Membrane Condenser for Water and Energy Recovery from Power Plant Flue Gas  

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

Dexin Wang Dexin Wang Principal Investigator Gas Technology Institute 1700 South Mount Prospect Rd Des Plaines, Il 60018 847-768-0533 dexin.wang@gastechnology.org TransporT MeMbrane Condenser for WaTer and energy reCovery froM poWer planT flue gas proMIs/projeCT no.: nT0005350 Background One area of the U.S. Department of Energy's (DOE) Innovations for Existing Plants (IEP) Program's research is being performed to develop advanced technologies to reuse power plant cooling water and associated waste heat and to investigate methods to recover water from power plant flue gas. Considering the quantity of water withdrawn and consumed by power plants, any recovery or reuse of this water can significantly reduce the plant's water requirements. Coal occurs naturally with water present (3-60 weight %), and the combustion

179

Effective Transport Properties Accounting for Electrochemical Reactions of Proton-Exchange Membrane Fuel Cell Catalyst Layers  

SciTech Connect (OSTI)

There has been a rapidly growing interest in three-dimensional micro-structural reconstruction of fuel cell electrodes so as to derive more accurate descriptors of the pertinent geometric and effective transport properties. Due to the limited accessibility of experiments based reconstruction techniques, such as dual-beam focused ion beam-scanning electro microscopy or micro X-Ray computed tomography, within sample micro-structures of the catalyst layers in polymer electrolyte membrane fuel cells (PEMFCs), a particle based numerical model is used in this study to reconstruct sample microstructure of the catalyst layers in PEMFCs. Then the reconstructed sample structure is converted into the computational grid using body-fitted/cut-cell based unstructured meshing technique. Finally, finite volume methods (FVM) are applied to calculate effective properties on computational sample domains.

Pharoah, Jon; Choi, Hae-Won; Chueh, Chih-Che; Harvey, David

2011-07-01T23:59:59.000Z

180

ZERO EMISSION POWER PLANTS USING SOLID OXIDE FUEL CELLS AND OXYGEN TRANSPORT MEMBRANES  

SciTech Connect (OSTI)

Over 16,700 hours of operational experience was gained for the Oxygen Transport Membrane (OTM) elements of the proposed SOFC/OTM zero-emission power generation concept. It was repeatedly demonstrated that OTMs with no additional oxidation catalysts were able to completely oxidize the remaining depleted fuel in a simulated SOFC anode exhaust at an O{sub 2} flux that met initial targets. In such cases, neither residual CO nor H{sub 2} were detected to the limits of the gas chromatograph (<10 ppm). Dried OTM afterburner exhaust streams contained up to 99.5% CO{sub 2}. Oxygen flux through modified OTMs was double or even triple that of the standard OTMs used for the majority of testing purposes. Both the standard and modified membranes in laboratory-scale and demonstration-sized formats exhibited stable performance over extended periods (2300 to 3500 hours or 3 to 5 months). Reactor contaminants, were determined to negatively impact OTM performance stability. A method of preventing OTM performance degradation was developed and proven to be effective. Information concerning OTM and seal reliability over extended periods and through various chemical and thermal shocks and cycles was also obtained. These findings were used to develop several conceptual designs for pilot (10 kWe) and commercial-scale (250 kWe) SOFC/OTM zero emission power generation systems.

G. Maxwell Christie; Troy M. Raybold

2003-06-10T23:59:59.000Z

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


181

Cycling of Rab Proteins: Role of Rab GDI in the Reversible Membrane Association of Rab GTP-Ases  

Science Journals Connector (OSTI)

Small GTPases of the Rab family are specific regulators of intracellular vesicular traffic. Mutational analysis of Rab proteins suggests that it is the membrane-bound and GTP-bound form of the molecule that is ac...

Oliver Ullrich; Marino Zerial

1995-01-01T23:59:59.000Z

182

Dr. Ing. /PhD / Dr.techn. Students supervised by Signe Kjelstrup 1. Torleif Holt, Transport and equilibrium properties of a cation exchange membrane (1983)  

E-Print Network [OSTI]

, (1996) 6. Magnar Ottøy, Mass and heat transfer in ion-exchange membranes (1996) 7. Belinda Flem, Peltier in the Polymer Electrolyte Membrane Fuel Cell (2007) 17. Isabella Inzoli, Coupled transports of heat and massDr. Ing. /PhD / Dr.techn. Students supervised by Signe Kjelstrup 1. Torleif Holt, Transport

Kjelstrup, Signe

183

E-Print Network 3.0 - abc transporter proteins Sample Search...  

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

Search Sample search results for: abc transporter proteins Page: << < 1 2 3 4 5 > >> 1 ATP-binding cassette protein E is involved in gene transcription and translation in...

184

E-Print Network 3.0 - abc transport proteins Sample Search Results  

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

Search Sample search results for: abc transport proteins Page: << < 1 2 3 4 5 > >> 1 ATP-binding cassette protein E is involved in gene transcription and translation in...

185

A Discussion of Conductivity Testing in High Temperature Membranes (lessons learned in assessing transport)  

Broader source: Energy.gov [DOE]

Presentation on conductivity testing in high temperature membranes given by Jim Boncella of Los Alamos National Laboratory at the High Temperature Membrane Working Group meeting in October 2005.

186

Development of an spFRET method to measure structure changes in ion exchange proteins  

E-Print Network [OSTI]

transporter, major facilitator superfamily, membrane transport, membrane transporter, OxlT, single molecule, spFRET, transport protein. Tightly coupled ion exchangers, such as the AE anion exchange systems only take place at an appreciable rate if a suitable substrate ion is bound to the transport site

Novotny, Lukas

187

Two Chlamydomonas CTR Copper Transporters with a Novel Cys-Met Motif Are Localized to the Plasma Membrane and  

E-Print Network [OSTI]

Two Chlamydomonas CTR Copper Transporters with a Novel Cys-Met Motif Are Localized to the Plasma Membrane and Function in Copper Assimilation W M. Dudley Page, Janette Kropat, Patrice P. Hamel,1, California 90095-1569 Inducible high-affinity copper uptake is key to copper homeostasis in Chlamydomonas

Meier, Iris

188

MitoNEET is a Uniquely Folded Outer Mitochondrial Membrane Protein  

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

MitoNEET is a Uniquely Folded Outer MitoNEET is a Uniquely Folded Outer Mitochondrial Membrane Protein Stabilized by Diabetes Drugs The rise in obesity in the United States parallels a dramatic increase in obesity-associated diseases, most notably type-2 diabetes. This disease is predicted to reach epidemic proportions in the next several decades (Zimmet et al 2001, Urek et al 2007). Thus, understanding the biochemical processes underlying type-2 diabetes and identifying new targets for therapeutic intervention are critical for national and world health. A drug of choice to treat type-II diabetes is pioglitazone, a thiazolidinedione (TZD) derivative originally thought to exert its effect through activation of the nuclear transcription factor PPARg. Recently, a novel protein target for pioglitazone was discovered and was called mitoNEET (Colca et al 2004). This protein is anchored to the outer mitochondrial membrane (OMM) (Wiley et al 2007). Contrary to predictions that this was a zinc-finger transcription factor we discovered that mitoNEET is a novel 2Fe-2S protein.

189

Transport of organelles by elastically coupled motor proteins  

E-Print Network [OSTI]

Motor-driven intracellular transport is a complex phenomenon where multiple motor proteins attached to a cargo are simultaneously engaged in pulling activity, often leading to tug-of-war and bidirectional motion. However, most mathematical and computational models ignore the details of the motor-cargo interaction. A few papers have studied more realistic models of cargo transport by including elastic motor-cargo coupling, but either restricts the number of motors and/or uses purely phenomenological forms for energy-dependent hopping rates. Here, we study a generic Model In which N motors are elastically coupled to a cargo, which itself is subject to thermal noise in the cytoplasm and an additional external applied force. The motor-hopping rates are chosen to satisfy detailed balance with respect to the energy of stretching. The master equation is converted to a linear Fokker-Planck equation (LFPE), which yields the average positions of the cargo and motors, as well as their fluctuations and correlation functions. We apply this formalism to two specific forms of the hopping rates. Analytical results are obtained for mean cargo velocity, diffusion coefficient and the average force experienced by each motor for arbitrary N, and compared with numerical simulations. The expansion procedure also allows us to quantify load-sharing features among the cargo-bound motors. In general, we observe significant deviations between analytical predictions based on LFPE and the corresponding numerical results, which suggests a prominent role for higher order corrections.

Deepak Bhat; Manoj Gopalakrishnan

2014-12-17T23:59:59.000Z

190

Escherichia coli SRP, Its Protein Subunit Ffh, and the Ffh M Domain Are Able To Selectively Limit Membrane Protein Expression When Overexpressed  

Science Journals Connector (OSTI)

...and source are credited. Escherichia coli SRP, Its Protein Subunit Ffh, and the Ffh...and E. Bibi. 2010. Escherichia-coli SRP, its protein subunit Ffh, and the Ffh...Escherichia coli signal recognition particle (SRP) system plays an important role in membrane...

Ido Yosef; Elena S. Bochkareva; Eitan Bibi

2010-06-01T23:59:59.000Z

191

Smart membranes for nitrate removal, water purification, and selective ion transportation  

DOE Patents [OSTI]

A computer designed nanoengineered membrane for separation of dissolved species. One embodiment provides an apparatus for treatment of a fluid that includes ions comprising a microengineered porous membrane, a system for producing an electrical charge across the membrane, and a series of nanopores extending through the membrane. The nanopores have a pore size such that when the fluid contacts the membrane, the nanopores will be in a condition of double layer overlap and allow passage only of ions opposite to the electrical charge across the membrane.

Wilson, William D. (Pleasanton, CA); Schaldach, Charlene M. (Pleasanton, CA); Bourcier, William L. (Livermore, CA); Paul, Phillip H. (Livermore, CA)

2009-12-15T23:59:59.000Z

192

Sensitivity Enhancement of Separated Local Field Experiments: Application to Membrane Proteins  

Science Journals Connector (OSTI)

Separated local field (SLF) experiments have been used for almost three decades to obtain structural information in solid-state NMR. ... Here, we propose a new suite of sensitivity enhanced SLF pulse sequences to measure CSA and DC for aligned membrane proteins and liquid crystalline molecules that will decrease the time needed for data acquisition. ... (1-3) These parameters are directly measured using separated local field (SLF) experiments that resolve the CSA of spin S and DC between spins I and S in two dimensions. ...

T. Gopinath; Raffaello Verardi; Nathaniel J. Traaseth; Gianluigi Veglia

2010-03-29T23:59:59.000Z

193

Cargo transportation by two species of motor protein  

E-Print Network [OSTI]

The cargo motion in living cells transported by two species of motor protein with different intrinsic directionality is discussed in this study. Similar to single motor movement, cargo steps forward and backward along microtubule stochastically. Recent experiments found that, cargo transportation by two motor species has a memory, it does not change its direction as frequently as expected, which means that its forward and backward step rates depends on its previous motion trajectory. By assuming cargo has only the least memory, i.e. its step direction depends only on the direction of its last step, two cases of cargo motion are detailed analyzed in this study: {\\bf (I)} cargo motion under constant external load; and {\\bf (II)} cargo motion in one fixed optical trap. Due to the existence of memory, for the first case, cargo can keep moving in the same direction for a long distance. For the second case, the cargo will oscillate in the trap. The oscillation period decreases and the oscillation amplitude increases with the motor forward step rates, but both of them decrease with the trap stiffness. The most likely location of cargo, where the probability of finding the oscillated cargo is maximum, may be the same as or may be different with the trap center, which depends on the step rates of the two motor species. Meanwhile, if motors are robust, i.e. their forward to backward step rate ratios are high, there may be two such most likely locations, located on the two sides of the trap center respectively. The probability of finding cargo in given location, the probability of cargo in forward/backward motion state, and various mean first passage times of cargo to give location or given state are also analyzed.

Yunxin Zhang

2012-11-06T23:59:59.000Z

194

Myocardial Reloading after Extracorporeal Membrane Oxygenation Alters Substrate Metabolism While Promoting Protein Synthesis  

SciTech Connect (OSTI)

Extracorporeal membrane oxygenation (ECMO) unloads the heart providing a bridge to recovery in children after myocardial stunning. Mortality after ECMO remains high.Cardiac substrate and amino acid requirements upon weaning are unknown and may impact recovery. We assessed the hypothesis that ventricular reloading modulates both substrate entry into the citric acid cycle (CAC) and myocardial protein synthesis. Fourteen immature piglets (7.8-15.6 kg) were separated into 2 groups based on ventricular loading status: 8 hour-ECMO (UNLOAD) and post-wean from ECMO (RELOAD). We infused [2-13C]-pyruvate as an oxidative substrate and [13C6]-L-leucine, as a tracer of amino acid oxidation and protein synthesis into the coronary artery. RELOAD showed marked elevations in myocardial oxygen consumption above baseline and UNLOAD. Pyruvate uptake was markedly increased though RELOAD decreased pyruvate contribution to oxidative CAC metabolism.RELOAD also increased absolute concentrations of all CAC intermediates, while maintaining or increasing 13C-molar percent enrichment. RELOAD also significantly increased cardiac fractional protein synthesis rates by >70% over UNLOAD. Conclusions: RELOAD produced high energy metabolic requirement and rebound protein synthesis. Relative pyruvate decarboxylation decreased with RELOAD while promoting anaplerotic pyruvate carboxylation and amino acid incorporation into protein rather than to the CAC for oxidation. These perturbations may serve as therapeutic targets to improve contractile function after ECMO.

Kajimoto, Masaki; Priddy, Colleen M.; Ledee, Dolena; Xu, Chun; Isern, Nancy G.; Olson, Aaron; Des Rosiers, Christine; Portman, Michael A.

2013-08-19T23:59:59.000Z

195

Zero Emission Power Plants Using Solid Oxide Fuel Cells and Oxygen Transport Membranes  

SciTech Connect (OSTI)

Siemens Westinghouse Power Corp. (SWPC) is engaged in the development of Solid Oxide Fuel Cell stationary power systems. SWPC has combined DOE Developmental funds with commercial customer funding to establish a record of successful SOFC field demonstration power systems of increasing size. SWPC will soon deploy the first unit of a newly developed 250 kWe Combined Heat Power System. It will generate electrical power at greater than 45% electrical efficiency. The SWPC SOFC power systems are equipped to operate on lower number hydrocarbon fuels such as pipeline natural gas, which is desulfurized within the SOFC power system. Because the system operates with a relatively high electrical efficiency, the CO2 emissions, {approx}1.0 lb CO2/ kW-hr, are low. Within the SOFC module the desulfurized fuel is utilized electrochemically and oxidized below the temperature for NOx generation. Therefore the NOx and SOx emissions for the SOFC power generation system are near negligible. The byproducts of the power generation from hydrocarbon fuels that are released into the environment are CO2 and water vapor. This forward looking DOE sponsored Vision 21 program is supporting the development of methods to capture and sequester the CO2, resulting in a Zero Emission power generation system. To accomplish this, SWPC is developing a SOFC module design, to be demonstrated in operating hardware, that will maintain separation of the fuel cell anode gas, consisting of H2, CO, H2O and CO2, from the vitiated air. That anode gas, the depleted fuel stream, containing less than 18% (H2 + CO), will be directed to an Oxygen Transport Membrane (OTM) Afterburner that is being developed by Praxair, Inc.. The OTM is supplied air and the depleted fuel. The OTM will selectively transport oxygen across the membrane to oxidize the remaining H2 and CO. The water vapor is then condensed from the totally 1.5.DOC oxidized fuel stream exiting the afterburner, leaving only the CO2 in gaseous form. That CO2 can then be compressed and sequestered, resulting in a Zero Emission power generation system operating on hydrocarbon fuel that adds only water vapor to the environment. Praxair has been developing oxygen separation systems based on dense walled, mixed electronic, oxygen ion conducting ceramics for a number of years. The oxygen separation membranes find applications in syngas production, high purity oxygen production and gas purification. In the SOFC afterburner application the chemical potential difference between the high temperature SOFC depleted fuel gas and the supplied air provides the driving force for oxygen transport. This permeated oxygen subsequently combusts the residual fuel in the SOFC exhaust. A number of experiments have been carried out in which simulated SOFC depleted fuel gas compositions and air have been supplied to either side of single OTM tubes in laboratory-scale reactors. The ceramic tubes are sealed into high temperature metallic housings which precludes mixing of the simulated SOFC depleted fuel and air streams. In early tests, although complete oxidation of the residual CO and H2 in the simulated SOFC depleted fuel was achieved, membrane performance degraded over time. The source of degradation was found to be contaminants in the simulated SOFC depleted fuel stream. Following removal of the contaminants, stable membrane performance has subsequently been demonstrated. In an ongoing test, the dried afterburner exhaust composition has been found to be stable at 99.2% CO2, 0.4% N2 and 0.6%O2 after 350 hours online. Discussion of these results is presented. A test of a longer, commercial demonstration size tube was performed in the SWPC test facility. A similar contamination of the simulated SOFC depleted fuel stream occurred and the performance degraded over time. A second test is being prepared. Siemens Westinghouse and Praxair are collaborating on the preliminary design of an OTM equipped Afterburner demonstration unit. The intent is to test the afterburner in conjunction with a reduced size SOFC test module that has the anode gas separati

Shockling, Larry A.; Huang, Keqin; Gilboy, Thomas E. (Siemens Westinghouse Power Corporation); Christie, G. Maxwell; Raybold, Troy M. (Praxair, Inc.)

2001-11-06T23:59:59.000Z

196

Development of Novel active transport membrane devices. Phase I. Final report, 31 October 1988--31 January 1994  

SciTech Connect (OSTI)

The main objective of this program was to identify and develop a technique for fabricating Active Transport Materials (ATM) into lab-scale membrane devices. Air Products met this objective by applying thin film, multilayer fabrication techniques to support the AT material on a substrate membrane. In Phase IA, spiral-wound hollow fiber membrane modules were fabricated and evaluated. These nonoptimized devices were used to demonstrate the AT-based separation of carbon dioxide from methane, hydrogen sulfide from methane, and ammonia from hydrogen. It was determined that a need exists for a more cost efficient and less energy intensive process for upgrading subquality natural gas. Air Products estimated the effectiveness of ATM for this application and concluded that an optimized ATM system could compete effectively with both conventional acid gas scrubbing technology and current membrane technology. In addition, the optimized ATM system would have lower methane loss and consume less energy than current alternative processes. Air Products made significant progress toward the ultimate goal of commercializing an advanced membrane for upgrading subquality natural gas. The laboratory program focused on developing a high performance hollow fiber substrate and fabricating and evaluating ATM-coated lab-scale hollow fiber membrane modules. Selection criteria for hollow fiber composite membrane supports were developed and used to evaluate candidate polymer compositions. A poly(amide-imide), PAI, was identified for further study. Conditions were identified which produced microporous PAI support membrane with tunable surface porosity in the range 100-1000{Angstrom}. The support fibers exhibited good hydrocarbon resistance and acceptable tensile strength though a higher elongation may ultimately be desirable. ATM materials were coated onto commercial and PAI substrate fiber. Modules containing 1-50 fibers were evaluated for permselectivity, pressure stability, and lifetime.

Laciak, D.V.; Quinn, R.; Choe, G.S.; Cook, P.J.; Tsai, Fu-Jya

1994-08-01T23:59:59.000Z

197

Myocardial Oxidative Metabolism and Protein Synthesis during Mechanical Circulatory Support by Extracorporeal Membrane Oxygenation  

SciTech Connect (OSTI)

Extracorporeal membrane oxygenation (ECMO) provides mechanical circulatory support essential for survival in infants and children with acute cardiac decompensation. However, ECMO also causes metabolic disturbances, which contribute to total body wasting and protein loss. Cardiac stunning can also occur which prevents ECMO weaning, and contributes to high mortality. The heart may specifically undergo metabolic impairments, which influence functional recovery. We tested the hypothesis that ECMO alters oxidative. We focused on the amino acid leucine, and integration with myocardial protein synthesis. We used a translational immature swine model in which we assessed in heart (i) the fractional contribution of leucine (FcLeucine) and pyruvate (FCpyruvate) to mitochondrial acetyl-CoA formation by nuclear magnetic resonance and (ii) global protein fractional synthesis (FSR) by gas chromatography-mass spectrometry. Immature mixed breed Yorkshire male piglets (n = 22) were divided into four groups based on loading status (8 hours of normal circulation or ECMO) and intracoronary infusion [13C6,15N]-L-leucine (3.7 mM) alone or with [2-13C]-pyruvate (7.4 mM). ECMO decreased pulse pressure and correspondingly lowered myocardial oxygen consumption (~ 40%, n = 5), indicating decreased overall mitochondrial oxidative metabolism. However, FcLeucine was maintained and myocardial protein FSR was marginally increased. Pyruvate addition decreased tissue leucine enrichment, FcLeucine, and Fc for endogenous substrates as well as protein FSR. Conclusion: The heart under ECMO shows reduced oxidative metabolism of substrates, including amino acids, while maintaining (i) metabolic flexibility indicated by ability to respond to pyruvate, and (ii) a normal or increased capacity for global protein synthesis, suggesting an improved protein balance.

Priddy, MD, Colleen M.; Kajimoto, Masaki; Ledee, Dolena; Bouchard, Bertrand; Isern, Nancy G.; Olson, Aaron; Des Rosiers, Christine; Portman, Michael A.

2013-02-01T23:59:59.000Z

198

Studies of protein folding on membranes and in crowded environments and bridging the research-teaching gap in K-12 science.  

E-Print Network [OSTI]

??This work deals with three important problems in membrane protein folding studies, namely the preparation and storage of homogeneous small unilamellar vesicles (SUV), the development (more)

Denos, Sharlene

2010-01-01T23:59:59.000Z

199

Additional Table 3. COGs Analyzed and their Descriptions COG Protein Name  

E-Print Network [OSTI]

protein COG1446 Asparaginase COG1464 ABC-type metal ion transport system, periplasmic component Putative salt-induced outer membrane protein COG3143 Chemotaxis protein COG3158 K+ transporter COG3160 protein A COG0753 Catalase COG0755 ABC-type transport system involved in cytochrome c biogenesis, permease

Gerstein, Mark

200

Conceptual design report for a Direct Hydrogen Proton Exchange Membrane Fuel Cell for transportation application  

SciTech Connect (OSTI)

This report presents the conceptual design for a Direct-Hydrogen-Fueled Proton Exchange Membrane (PEM) Fuel Cell System for transportation applications. The design is based on the initial selection of the Chrysler LH sedan as the target vehicle with a 50 kW (gross) PEM Fuel Cell Stack (FCS) as the primary power source, a battery-powered Load Leveling Unit (LLU) for surge power requirements, an on-board hydrogen storage subsystem containing high pressure gaseous storage, a Gas Management Subsystem (GMS) to manage the hydrogen and air supplies for the FCS, and electronic controllers to control the electrical system. The design process has been dedicated to the use of Design-to-Cost (DTC) principles. The Direct Hydrogen-Powered PEM Fuel Cell Stack Hybrid Vehicle (DPHV) system is designed to operate on the Federal Urban Driving Schedule (FUDS) and Hiway Cycles. These cycles have been used to evaluate the vehicle performance with regard to range and hydrogen usage. The major constraints for the DPHV vehicle are vehicle and battery weight, transparency of the power system and drive train to the user, equivalence of fuel and life cycle costs to conventional vehicles, and vehicle range. The energy and power requirements are derived by the capability of the DPHV system to achieve an acceleration from 0 to 60 MPH within 12 seconds, and the capability to achieve and maintain a speed of 55 MPH on a grade of seven percent. The conceptual design for the DPHV vehicle is shown in a figure. A detailed description of the Hydrogen Storage Subsystem is given in section 4. A detailed description of the FCS Subsystem and GMS is given in section 3. A detailed description of the LLU, selection of the LLU energy source, and the power controller designs is given in section 5.

NONE

1995-09-05T23:59:59.000Z

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


201

Membrane Porters of ATP-Binding Cassette Transport Systems Are Polyphyletic  

E-Print Network [OSTI]

REVIEW Membrane Porters of ATP-Binding Cassette Transportat Springerlink.com Abstract The ATP-binding cassette (ABC)classi?ed according to the ATP hydrolyzing constituents,

Wang, Bin; Dukarevich, Maxim; Sun, Eric I.; Yen, Ming Ren; Saier, Milton H.

2009-01-01T23:59:59.000Z

202

Magnaporthe grisea Pth11p Is a Novel Plasma Membrane Protein That Mediates Appressorium Differentiation in Response to Inductive Substrate Cues  

Science Journals Connector (OSTI)

...heterokaryotic and vegetative diploid phases of Magnaporthe grisea Gilbert R. Johnson A. Dean R. Chemical signals responsible for...Sequence Base Sequence DNA, Fungal Fungal Proteins Hordeum microbiology Magnaporthe genetics metabolism pathogenicity Membrane Proteins...

Todd M. DeZwaan; Anne M. Carroll; Barbara Valent; James A. Sweigard

203

Selective Gas Transport Through Few-Layered Graphene and Graphene Oxide Membranes  

Science Journals Connector (OSTI)

...for membrane applications because of ultimate...deposition (CVD) has recently...synthesized via CVD has a polycrystalline...spray and spin coatings (16). GO films...after several coatings, both membrane...coated by a GO thin film without detectable...cracks under an optical microscope...

Hyo Won Kim; Hee Wook Yoon; Seon-Mi Yoon; Byung Min Yoo; Byung Kook Ahn; Young Hoon Cho; Hye Jin Shin; Hoichang Yang; Ungyu Paik; Soongeun Kwon; Jae-Young Choi; Ho Bum Park

2013-10-04T23:59:59.000Z

204

Water Transport in Polymer Electrolyte Membrane Electrolyzers Used to Recycle Anhydrous HCl  

E-Print Network [OSTI]

is car- ried out in an electrolyzer similar to a H2-O2 polymer electrolyte membrane PEM fuel cell. The Du-coated Nafion 115 membrane was measured as a function of HCl flow rate and temperature at a constant cell 50% of the chlorine used in the chemical industry ends up as hydrogen chloride, a waste byproduct.2

Weidner, John W.

205

Does Magnesium Transport Protein (MgtE) Contribute to the Antibiotic Resistance of Pseudomonas aeruginosa?  

E-Print Network [OSTI]

Does Magnesium Transport Protein (MgtE) Contribute to the Antibiotic Resistance of Pseudomonas is more resistant to antibiotics. The purpose of this project was to find out if the magnesium transport by using two different strains of P.aeruginosa; PA14 wild-type and GGA52 mutant (without the magnesium

Zhou, Yaoqi

206

Protein nucleocytoplasmic transport and its light regulation in plants  

E-Print Network [OSTI]

of plant cells and how light may exert its regulatory effect. Nuclear import system An overview investigations into plant nuclear transport systems and specific cases where nucleocytoplasmic transport conditions. Among a variety of environmental stimuli that affect plants, light exerts the most promi- nent

Deng, Xing-Wang

207

ABCG Transporters Are Required for Suberin and Pollen Wall Extracellular Barriers in Arabidopsis  

Science Journals Connector (OSTI)

...ABC) transporter proteins are found in both prokaryotes and eukaryotes and pump diverse substrates across membranes using energy from ATP hydrolysis (Higgins and Linton, 2004). Canonical ABC transporters have two repeats each of a transmembrane domain...

Vandana Yadav; Isabel Molina; Kosala Ranathunge; Indira Queralta Castillo; Steven J. Rothstein; Jason W. Reed

2014-09-12T23:59:59.000Z

208

Membrane Bound: C2-Domain Abscisic Acid-Related Proteins Help Abscisic Acid Receptors Get Where They Need to Go  

Science Journals Connector (OSTI)

...Membrane Bound: C2-Domain Abscisic Acid-Related Proteins Help Abscisic Acid Receptors Get Where They Need to Go Jennifer Lockhart jlockhart@aspb.org Science Editor www.plantcell.org/cgi/doi/10.1105/tpc.114.134411

Jennifer Lockhart

2014-12-02T23:59:59.000Z

209

Transcription-Dependent and Transcription-Independent Nuclear Transport of hnRNP Proteins  

E-Print Network [OSTI]

. In mitosis, as the nuclear envelope breaks down, hnRNPs disperse throughout the cell. At the end of mitosisTranscription-Dependent and Transcription- Independent Nuclear Transport of hnRNP Proteins SERAFfN PIN'OL-ROMA AND GIDEON DREYFUSS Heterogeneous nuclear RNAs and specific nuclear proteins form

Dreyfuss, Gideon

210

Self-Assembly and Mass Transport in Membranes for Artificial Photosynthesis  

E-Print Network [OSTI]

45 CHAPTER 3. SELF-ASSEMBLY AND TRANSPORT LIMITATIONS IN7371. CHAPTER 3. SELF-ASSEMBLY AND TRANSPORT LIMITATIONS IN2. CONTROLLING NANOROD SELF-ASSEMBLY IN POLYMER THIN-FILMS

Modestino, Miguel Antonio

2013-01-01T23:59:59.000Z

211

Investigation of the performance and water transport of a polymer electrolyte membrane (pem) fuel cell  

E-Print Network [OSTI]

Fuel cell performance was obtained as functions of the humidity at the anode and cathode sites, back pressure, flow rate, temperature, and channel depth. The fuel cell used in this work included a membrane and electrode assembly (MEA) which...

Park, Yong Hun

2009-05-15T23:59:59.000Z

212

Self-Assembly and Mass Transport in Membranes for Artificial Photosynthesis  

E-Print Network [OSTI]

membranes are in hydrogen fuel- cells and electrolyzers. Thefuel cells and electrolyzers used both for hydrogenhydrogen production and device geometry requirements dictated by the light absorption. In fuel cells,

Modestino, Miguel Antonio

2013-01-01T23:59:59.000Z

213

Experimental characterization of water sorption and transport properties of polymer electrolyte membranes for fuel cells.  

E-Print Network [OSTI]

??L'objectif gnral de cette thse de doctorat est de caractriser les proprits de membranes PFSA de type Nafion N115 et Nafion NRE212 en termes de (more)

Maldonado Snchez, Libeth

2012-01-01T23:59:59.000Z

214

Active membrane fluctuations studied by micropipet aspiration J.-B. Manneville,1  

E-Print Network [OSTI]

, mostly performed by proteins embedded inside the lipid bi- layer, such as solute transport via ion channels or pumps, cell locomotion and adhesion, membrane transport through exo- cytic and endocyticActive membrane fluctuations studied by micropipet aspiration J.-B. Manneville,1 P. Bassereau,1

Ramaswamy, Sriram

215

Spectroscopic studies of tryptophan and membrane- associated peptides  

E-Print Network [OSTI]

Thermodynamics of membrane protein folding measured byThermodynamics of Membrane Protein Folding: Lessons from theKim, Thermodynamics of membrane protein folding measured by

Schlamadinger, Diana Elizabeth

2011-01-01T23:59:59.000Z

216

SLDMOL: A tool for the structural characterization of thermally disordered membrane proteins  

Science Journals Connector (OSTI)

Abstract SLDMOL is a program for modeling the 1-D scattering length density (SLD) profile of proteins at the lipid membranesolution interface or adsorbed to other surfaces. The program reads experimental SLD data from neutron or X -ray reflectivity measurements and compares the results to a trajectory of protein structures, finding the conformation and orientation that best fits the experimental data. SLDMOL is a freely distributed open source program written in python that can be run independently using command lines or a GUI. SLDMOL has also been integrated into the larger SASSIE package extending molecular modeling capabilities. Sample environment conditions can be replicated including H2O/D2O solvent contrasts, specific amino acid deuteration and complex molecular assemblies. Ensembles of protein conformations can be generated independently (e.g.molecular dynamics simulations) or with SASSIE. For each individual structure a best-fit SLD profile is outputted along with a goodness of fit parameter, protein depth penetration and surface coverage. In addition to individual comparisons SLD profiles can be calculated over ensemble averages of protein structures. As a result, SLDMOL provides a detailed molecular interpretation of reflectivity data or conversely can be used to predict experimental outcomes for different protein conformation and specific deuteration schemes prior to measurements. Program summary Program title: SLDMOL Catalogue identifier: AETX_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AETX_v1_0.html Program obtainable from: CPC Program Library, Queens University, Belfast, N. Ireland Licensing provisions: GNU General Public License, version 3 No. of lines in distributed program, including test data, etc.: 3302107 No. of bytes in distributed program, including test data, etc.: 125715760 Distribution format: tar.gz Programming language: Python. Computer: PC/Mac. Operating system: 32- and 64-bit Linux (Ubuntu 10.04, Centos 5.6) and Mac OS X (10.710.9). RAM: 1 GB Classification: 3. External routines: Python 2.6.5, numpy 1.4.0, scipy 0.8.0, Tcl 8.5, Tk 8.5, Mac installation requires Xcode 3 development tools. Subprograms used: CatId Title Reference AEKL_v1_0 SASSIE CPC183(2012)382 Nature of problem: Reflectivity is a powerful technique to study the conformation of biological molecules at surface and interfaces. Open source software that facilitates computational modeling and interpretation of experimental results in terms of detailed molecular structure is currently lacking. Solution method: SLDMOL takes one or an ensemble of atomistic configurations of proteins and compares them to 1-D scattering length density (SLD) profiles determined from reflectivity experiments. Protein structures can be generated independently (e.g.molecular dynamics simulations) or through the SASSIE software package. SLDMOL performs an optimization to determine which structure best fits the SLD profile. Structures can also be averaged either directly or through a Monte-Carlo weighting algorithm. Finally SLDMOL allows the modeling of reflectivity experiments through the in silico selective deuteration of amino acids and the calculation of SLD profiles in a number of different aqueous solvent contrasts. Additional comments: !!!!Due to the large file size, SLDMOL is not delivered directly when download or Email is requested. Instead an html file giving details of how the program can be obtained is sent.!!!! Running time: Varies depending on application. Typically 10min to 24h depending on the number of structures to be evaluated.

Joseph E. Curtis; Hailiang Zhang; Hirsh Nanda

2014-01-01T23:59:59.000Z

217

Membrane extraction of Rab proteins by GDP dissociation inhibitor characterized using attenuated  

E-Print Network [OSTI]

dissociation inhibitor (GDI) solubilizes prenylated Rab GTPases from and shuttles them between membranes spectroscopy to directly ob- serve extraction of Rab GTPases from model membranes by GDI. In their native form reflection experiments show that GDI genuinely accelerates the intrinsic Rab membrane dissociation

Gerwert, Klaus

218

E-Print Network 3.0 - anandamide membrane transporter Sample...  

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

of the putative anandamide transporter that also... , Kaczocha M, Studholme KM, Deutsch DG (2003). Evidence against the presence of an ... Source: Cravatt, Benjamin -...

219

Aptamer Directly Evolved from Live Cells Recognizes Membrane Bound Immunoglobin  

E-Print Network [OSTI]

. These include cell signaling, cell-cell interactions, ion/solute transport that facilitates the exchangeAptamer Directly Evolved from Live Cells Recognizes Membrane Bound Immunoglobin Heavy Mu Chain, and Weihong Tan The identification of tumor related cell membrane protein targets is important

Tan, Weihong

220

E-Print Network 3.0 - ankyrin-repeat membrane protein Sample...  

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

10 Stabilizing IB by "Consensus" Design Diego U. Ferreiro1,3 Summary: Keywords: protein folding; ankyrin repeat protein; NF-B; transcription factor; repeat protein...

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


221

Measurements of water uptake and transport properties in anion-exchange membranes  

E-Print Network [OSTI]

, the electro-osmotic drag (EOD) coefficient, and the mass-transfer coefficient of water at the cathode catalyst/membrane interface falls in the range of 1.0 ? 10?6 to 1.0 ? 10?5 m s?1 . The EOD coefficients measured at 30 C

Zhao, Tianshou

222

Water-Protein Interactions of an Arginine-Rich Membrane Peptide in Lipid Bilayers Investigated by Solid-State Nuclear Magnetic Resonance Spectroscopy  

E-Print Network [OSTI]

from water to proteins.1 For microcrystalline proteins in the solid-state, magic-angle- spinning (MASWater-Protein Interactions of an Arginine-Rich Membrane Peptide in Lipid Bilayers Investigated by Solid-State Nuclear Magnetic Resonance Spectroscopy Shenhui Li, Yongchao Su, Wenbin Luo, and Mei Hong

Hong, Mei

223

Protein domain organisation: adding order  

E-Print Network [OSTI]

4 81811 membrane_organization_and_biogenesis 4 81811 vesicle-mediated_transport 4 81811 intracellular_protein_transport 4 54117 immune_response 3 54117 negative_regulation_of_cell_proliferation 3 54117 signal_transducer_activity 3 50715 ligase... -type_endopeptidase_activity 4 69055 binding 3 52788 identical_protein_binding 4 54585 nucleoside-triphosphatase_activity 3 54585 ATPase_activity 3 54585 protein_transport 3 54585 caspase_activation 3 54585 unfolded_protein_response 3 54585 magnesium_ion_binding 3 54585 protein...

Kummerfeld, Sarah K; Teichmann, Sarah A

2009-01-29T23:59:59.000Z

224

Transmembrane protein PERP is a component of tessellate junctions and of other junctional and non-junctional plasma membrane regions in diverse epithelial and epithelium-derived cells  

E-Print Network [OSTI]

Protein PERP (p53 apoptosis effector related to PMP-22) is a small (21.4 kDa) transmembrane polypeptide with an amino acid sequence indicative of a tetraspanin character. It is enriched in the plasma membrane and apparently ...

Franke, Werner W.

225

Ethanol-induced regulation of the human dopamine transporter.  

E-Print Network [OSTI]

??The dopamine transporter (DAT) is a plasma membrane-bound protein, localized on peri-synaptic terminals of dopaminergic (DA) neurons. DAT is responsible for terminating DA signaling by (more)

Riherd Methner, Deanna Nicole

2014-01-01T23:59:59.000Z

226

Self-Induced Docking Site of a Deeply Embedded Peripheral Membrane Protein  

E-Print Network [OSTI]

paramagnetic resonance (EPR). Noting that in the membrane-bound state the three calcium binding loops features: an eight-strand antiparallel b-sandwich, and three negatively charged calcium-binding loops (CBLs are complexed to two calcium ions, we initially restrained the calcium ions at the membrane depth determined

White, Stephen

227

Ligand-gated Diffusion Across the Bacterial Outer Membrane  

SciTech Connect (OSTI)

Ligand-gated channels, in which a substrate transport pathway is formed as a result of the binding of a small-molecule chemical messenger, constitute a diverse class of membrane proteins with important functions in prokaryotic and eukaryotic organisms. Despite their widespread nature, no ligand-gated channels have yet been found within the outer membrane (OM) of Gram-negative bacteria. Here we show, using in vivo transport assays, intrinsic tryptophan fluorescence and X-ray crystallography, that high-affinity (submicromolar) substrate binding to the OM long-chain fatty acid transporter FadL from Escherichia coli causes conformational changes in the N terminus that open up a channel for substrate diffusion. The OM long-chain fatty acid transporter FadL from E. coli is a unique paradigm for OM diffusion-driven transport, in which ligand gating within a {beta}-barrel membrane protein is a prerequisite for channel formation.

B Lepore; M Indic; H Pham; E Hearn; D Patel; B van den Berg

2011-12-31T23:59:59.000Z

228

Ammonium Bicarbonate Transport in Anion Exchange Membranes for Salinity Gradient Energy  

E-Print Network [OSTI]

such as reverse electrodialysis (RED) rely on highly selective anion transport through polymeric anion exchange to address global energy needs, such as reverse electro- dialysis1-4 (RED), capacitive energy extraction based on Donnan potential5 (CDP), and capacitive reverse electro- dialysis6 (CRED), has encouraged

229

A Key Role for Heat Shock Protein 70 in the Localization and Insertion of Tombusvirus Replication Proteins to Intracellular Membranes  

Science Journals Connector (OSTI)

...for expression of Ssa1-HF has been described elsewhere...express the C-terminal fusion proteins Pex13-cyan...NT-C. The N-terminal fusion proteins YFP-p33 and...elsewhere (43). Confocal laser microscopy. To view yeast...different fluorescent fusion proteins, yeast strains...

Robert Yung-Liang Wang; Jozsef Stork; Peter D. Nagy

2009-01-19T23:59:59.000Z

230

Assembly and Transport of Nanocrystal CdSe Quantum Dot Nanocomposites Using Microtubules and Kinesin Motor Proteins  

Science Journals Connector (OSTI)

Assembly and Transport of Nanocrystal CdSe Quantum Dot Nanocomposites Using Microtubules and Kinesin Motor Proteins ... motors in synthetic environments, we use highly oriented poly(tetrafluoroethylene) films functionalized with the motor protein kinesin and find that they are able to direct the motion of microtubules in straight lines along the films' orientation axes. ... The controlling transport direction is considered to be an essential step for future developments of motor protein-based microdevices working in nanometer steps. ...

George D. Bachand; Susan B. Rivera; Andrew K. Boal; Jennifer Gaudioso; Jun Liu; Bruce C. Bunker

2004-03-26T23:59:59.000Z

231

Highly permeable polymeric membranes based on the incorporation of the functional water channel protein Aquaporin Z  

Science Journals Connector (OSTI)

...also be a large step in improving the economics of desalination for drinking water applications. Desalination is becoming increasingly important for...RO is a commercial reverse-osmosis desalination membrane with data from Matsura (38...

Manish Kumar; Mariusz Grzelakowski; Julie Zilles; Mark Clark; Wolfgang Meier

2007-01-01T23:59:59.000Z

232

Interaction of the Effector Domain of MARCKS and MARCKS-Related Protein with Lipid Membranes Revealed by Electric Potential Measurements  

Science Journals Connector (OSTI)

Interaction of the Effector Domain of MARCKS and MARCKS-Related Protein with Lipid Membranes Revealed by Electric Potential Measurements ... The water was deionized (NANOpure, Barnstead, IA) to a specific resistance, >17 M?cm. ... According to the Gouy?Chapman theory, the surface potential ? at the membrane/water interface for a fixed homogeneously smeared surface charge density ? in the presence of a 1:1 electrolyte (e.g., KCl) with a concentration of n0 ions per unit volume is given by (30) where k is the Boltzmann constant, T the temperature, e the elementary charge, ?0 the dielectric constant of the vacuum, and ?w ? 80 the relative dielectric constant of water. ...

Gnther Bhr; Anke Diederich; Guy Vergres; Mathias Winterhalter

1998-10-29T23:59:59.000Z

233

Recent Progress in the Structure Determination of GPCRs, a Membrane Protein Family with High Potential as Pharmaceutical Targets  

SciTech Connect (OSTI)

G protein-coupled receptors (GPCRs) constitute a highly diverse and ubiquitous family of integral membrane proteins, transmitting signals inside the cells in response to an assortment of disparate extra-cellular stimuli. Their strategic location on the cell surface and their involvement in crucial cellular and physiological processes turn these receptors into highly important pharmaceutical targets. Recent technological developments aimed at stabilization and crystallization of these receptors have led to significant breakthroughs in GPCR structure determination efforts. One of the successful approaches involved receptor stabilization with the help of a fusion partner combined with crystallization in lipidic cubic phase (LCP). The success of using an LCP matrix for crystallization is generally attributed to the creation of a more native, membrane-like stabilizing environment for GPCRs just prior to nucleation and to the formation of type I crystal lattices, thus generating highly ordered and strongly diffracting crystals. Here they describe protocols for reconstituting purified GPCRs in LCP, performing pre-crystallization assays, setting up crystallization trials in manual mode, detecting crystallization hits, optimizing crystallization conditions, harvesting, and collecting crystallographic data. The protocols provide a sensible framework for approaching crystallization of stabilized GPCRs in LCP, however, as in any crystallization experiment, extensive screening and optimization of crystallization conditions as well as optimization of protein construct and purification steps are required. The process remains risky and these protocols do not necessarily guarantee success.

Cherezov, Vadim; Abola, Enrique; Stevens, Raymond C.

2012-05-09T23:59:59.000Z

234

Salinity tolerance in plants: attempts to manipulate ion transport  

E-Print Network [OSTI]

Ion transport is the major determining factor of salinity tolerance in plants. A simple scheme of a plant cell with ion fluxes provides basic understanding of ion transport and the corresponding changes of ion concentrations under salinity. The review describes in detail basic principles of ion transport for a plant cell, introduces set of transporters essential for sodium and potassium uptake and efflux, analyses driving forces of ion transport and compares ion fluxes measured by several techniques. Study of differences in ion transport between salt tolerant halophytes and salt-sensitive plants with an emphasis on transport of potassium and sodium via plasma membranes offers knowledge for increasing salinity tolerance. Effects of salt stress on ion transport properties of membranes show huge opportunities for manipulating ion transport. Several attempts to overexpress or knockout ion transporters for changing salinity tolerance are described. Future perspectives are questioned with more attention given to potential candidate ion channels and transporters for altered expression. The potential direction of increasing salinity tolerance by modifying ion channels and transporters is discussed and questioned. An alternative approach from synthetic biology is to modify the existing membrane transport proteins or create new ones with desired properties for transforming agricultural crops. The approach had not been widely used earlier and leads also to theoretical and pure scientific aspects of protein chemistry, structure-function relations of membrane proteins, systems biology and physiology of stress and ion homeostasis.

Vadim Volkov

2014-11-06T23:59:59.000Z

235

SEPARATION OF PROTEINS BY ION EXCHANGE AND MEMBRANE CHROMATOGRAPHY: BUFFER COMPOSITION, INTERFERING IMPURITIES AND FOULING CONSIDERATIONS  

E-Print Network [OSTI]

on identifying major impurity and optimization of solution properties for target protein purification. The second approach consisted of designing an adsorbent that interacted specifically with the target molecule. The first study included modification of protein...

Imam, Tahmina

2010-01-16T23:59:59.000Z

236

Role of Diacylglycerol in PKD Recruitment to the TGN and Protein Transport to the Plasma Membrane  

Science Journals Connector (OSTI)

...P. Bacon C. W. Riley R. T. Merrill A. H. Jr...93 , 120 ( 1978 ). 15 Pappu A. S. Hauser G. , Neurochem...532 (1985). 18 Davis R. J. Ganong B. R. Bell...1978) . 15. A. S. Pappu and G. Hauser, Neurochem...532-(1985). 18. R. J. Davis, B. R. Ganong...

Carole L. Baron; Vivek Malhotra

237

VOLUME 80, NUMBER 20 P H Y S I C A L R E V I E W L E T T E R S 18 MAY 1998 Spontaneous Onset of Coherence and Energy Storage by Membrane Transporters  

E-Print Network [OSTI]

of Coherence and Energy Storage by Membrane Transporters in an RLC Electric Circuit Imre Derényi and R. Dean that oscillating or fluctuating electric fields can drive thermodynami- cally uphill transport of ions catalyzed by a molecular ion pump, the Na,K-ATPase. Theory suggests that if the transport reaction is very far from

Derényi, Imre

238

Effect of Multimerization on Membrane Association of Rous Sarcoma Virus and HIV-1 Matrix Domain Proteins  

Science Journals Connector (OSTI)

...each other, making the overall shape of Gag like that of a horseshoe (80, 81). Moreover, from low-angle neutron scattering analyses of HIV-1 Gag bound to a tethered membrane, it appears that the horseshoe shape is maintained, implying...

Robert A. Dick; Elena Kamynina; Volker M. Vogt

2013-10-09T23:59:59.000Z

239

Comparison of soy protein concentrates produced by membrane filtration and acid precipitation  

E-Print Network [OSTI]

, respectively. A series of operations including pH adjustment (8.0), agitation (250 rpm, 30 min), sonication (40 dB, 20 min), homogenization (3 min), and centrifugation (3,000 x g, 15 min) were followed. For the membrane processing, the ultrafiltration cartridge...

Kim, Hyun Jung

2003-01-01T23:59:59.000Z

240

Self-organization of the fluid mosaic of charged channel proteins in membranes  

Science Journals Connector (OSTI)

...K is scaled by the electric length constant {M...density, however, the electric effect of increasing...a bath of negligible resistance. The coupled dynam...potential E?, and the resistance r1 are to be determined...membrane potential) in two elementary geometries (free cable...

P Fromherz

1988-01-01T23:59:59.000Z

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


241

Research and development of proton-exchange membrane (PEM) fuel cell system for transportation applications. Phase I final report  

SciTech Connect (OSTI)

Objective during Phase I was to develop a methanol-fueled 10-kW fuel cell power source and evaluate its feasibility for transportation applications. This report documents research on component (fuel cell stack, fuel processor, power source ancillaries and system sensors) development and the 10-kW power source system integration and test. The conceptual design study for a PEM fuel cell powered vehicle was documented in an earlier report (DOE/CH/10435-01) and is summarized herein. Major achievements in the program include development of advanced membrane and thin-film low Pt-loaded electrode assemblies that in reference cell testing with reformate-air reactants yielded performance exceeding the program target (0.7 V at 1000 amps/ft{sup 2}); identification of oxidation catalysts and operating conditions that routinely result in very low CO levels ({le} 10 ppm) in the fuel processor reformate, thus avoiding degradation of the fuel cell stack performance; and successful integrated operation of a 10-kW fuel cell stack on reformate from the fuel processor.

NONE

1996-01-01T23:59:59.000Z

242

Expression of the IRT1 Metal Transporter Is Controlled by Metals at the Levels of Transcript and Protein Accumulation  

Science Journals Connector (OSTI)

...transport of cadmium, it may be possible to engineer plants that specifically hyperaccumulate...will not be a straightforward matter to engineer plants that accumulate iron currently...protein sequence and is unique to IRT1 (Quality Controlled Biochemicals, Hopkinton...

Erin L. Connolly; Janette P. Fett; Mary Lou Guerinot

243

Classic Nuclear Localization Signals and a Novel Nuclear Localization Motif Are Required for Nuclear Transport of Porcine Parvovirus Capsid Proteins  

Science Journals Connector (OSTI)

...Reserved. 15 October 2014 research-article Virus-Cell Interactions Classic Nuclear Localization Signals and a Novel Nuclear Localization Motif Are Required for Nuclear Transport of Porcine Parvovirus Capsid Proteins Maude Boisvert Veronique Bouchard-Levesque...

Maude Boisvert; Vronique Bouchard-Lvesque; Sandra Fernandes; Peter Tijssen

2014-07-30T23:59:59.000Z

244

Model Cell Membranes  

Science Journals Connector (OSTI)

... are being used as model systems to test particular hypotheses in membrane transport. Thus, Tosteson and his colleagues (Andreoli et al., J. Gen. PhysioL, 50, 1729; ...

A Correspondent

1968-01-13T23:59:59.000Z

245

Folding amphipathic helices into membranes: Amphiphilicity trumps hydrophobicity  

E-Print Network [OSTI]

C. (1999). Membrane protein folding and stability: PhysicalA. S. & Hristova, K. (1998). Protein folding in membranes:Mutational analysis of protein folding and stability. In

Fernndez-Vidal, Mnica; Jayasinghe, Sajith; Ladokhin, Alexey S; White, Stephen H

2007-01-01T23:59:59.000Z

246

Transportation  

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

Transportation Transportation Transportation of Depleted Uranium Materials in Support of the Depleted Uranium Hexafluoride Conversion Program Issues associated with transport of depleted UF6 cylinders and conversion products. Conversion Plan Transportation Requirements The DOE has prepared two Environmental Impact Statements (EISs) for the proposal to build and operate depleted uranium hexafluoride (UF6) conversion facilities at its Portsmouth and Paducah gaseous diffusion plant sites, pursuant to the National Environmental Policy Act (NEPA). The proposed action calls for transporting the cylinder at ETTP to Portsmouth for conversion. The transportation of depleted UF6 cylinders and of the depleted uranium conversion products following conversion was addressed in the EISs.

247

Structural Insights into Membrane Targeting by the Flagellar Calcium-binding Protein (FCaBP) a Myristoylated and Palmitoylated Calcium Sensor in Trypanosoma cruzi  

SciTech Connect (OSTI)

The flagellar calcium-binding protein (FCaBP) of the protozoan Trypanosoma cruzi is targeted to the flagellar membrane where it regulates flagellar function and assembly. As a first step toward understanding the Ca{sup 2+}-induced conformational changes important for membrane-targeting, we report here the x-ray crystal structure of FCaBP in the Ca{sup 2+}-free state determined at 2.2{angstrom} resolution. The first 17 residues from the N terminus appear unstructured and solvent-exposed. Residues implicated in membrane targeting (Lys-19, Lys-22, and Lys-25) are flanked by an exposed N-terminal helix (residues 26-37), forming a patch of positive charge on the protein surface that may interact electrostatically with flagellar membrane targets. The four EF-hands in FCaBP each adopt a 'closed conformation' similar to that seen in Ca{sup 2+}-free calmodulin. The overall fold of FCaBP is closest to that of grancalcin and other members of the penta EF-hand superfamily. Unlike the dimeric penta EF-hand proteins, FCaBP lacks a fifth EF-hand and is monomeric. The unstructured N-terminal region of FCaBP suggests that its covalently attached myristoyl group at the N terminus may be solvent-exposed, in contrast to the highly sequestered myristoyl group seen in recoverin and GCAP1. NMR analysis demonstrates that the myristoyl group attached to FCaBP is indeed solvent-exposed in both the Ca{sup 2+}-free and Ca{sup 2+}-bound states, and myristoylation has no effect on protein structure and folding stability. We propose that exposed acyl groups at the N terminus may anchor FCaBP to the flagellar membrane and that Ca{sup 2+}-induced conformational changes may control its binding to membrane-bound protein targets..

J Wingard; J Ladner; M Vanarotti; A Fisher; H Robinson; K Buchanan; D Engman; J Ames

2011-12-31T23:59:59.000Z

248

Deciphering the Mechanism of E. coli tat Protein Transport: Kinetic Substeps and Cargo Properties  

E-Print Network [OSTI]

? (Blaudeck et al., 2003; Bogsch et al., 1997). The c-region of Sec and Tat precursors also contains a recognition sequence for signal peptidase I (LepB) (Luke et al., 2009), which is required for post-transport processing of the precursor into its mature... the concentration of precursor proteins is higher in the cytoplasm as compared to the periplasm, where they are processed into their mature forms by the signal peptidase LepB (Luke et al., 2009), creating a concentration gradient. The alternative model...

Whitaker, Neal William 1982-

2012-12-03T23:59:59.000Z

249

Role of Individual Positive Charges in the Membrane Orientation and Activity of Transporters of the Small Multidrug Resistance Family  

Science Journals Connector (OSTI)

Molecular Microbiology and Membrane Enzymology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands ... *Molecular Microbiology, Nijenborgh 7, 9747AG Groningen, The Netherlands. ...

Magdalena A. Kolbusz; Dirk Jan Slotboom; Juke S. Lolkema

2012-10-08T23:59:59.000Z

250

Nanoscale study of reactive transport in catalyst layer of proton exchange membrane fuel cells with precious and non-precious catalysts using lattice Boltzmann method  

E-Print Network [OSTI]

High-resolution porous structures of catalyst layer (CL) with multicomponent in proton exchange membrane fuel cells are reconstructed using a reconstruction method called quartet structure generation set. Characterization analyses of nanoscale structures are implemented including pore size distribution, specific area and phase connectivity. Pore-scale simulation methods based on the lattice Boltzmann method are developed and used to predict the macroscopic transport properties including effective diffusivity and proton conductivity. Nonuniform distributions of ionomer in CL generates more tortuous pathway for reactant transport and greatly reduces the effective diffusivity. Tortuosity of CL is much higher than conventional Bruggeman equation adopted. Knudsen diffusion plays a significant role in oxygen diffusion and significantly reduces the effective diffusivity. Reactive transport inside the CL is also investigated. Although the reactive surface area of non-precious metal catalyst (NPMC) CL is much higher t...

Chen, Li; Kang, Qinjun; Holby, Edward F; Tao, Wen-Quan

2014-01-01T23:59:59.000Z

251

Transportation  

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

Health Risks » Transportation Health Risks » Transportation DUF6 Health Risks line line Accidents Storage Conversion Manufacturing Disposal Transportation Transportation A discussion of health risks associated with transport of depleted UF6. Transport Regulations and Requirements In the future, it is likely that depleted uranium hexafluoride cylinders will be transported to a conversion facility. For example, it is currently anticipated that the cylinders at the ETTP Site in Oak Ridge, TN, will be transported to the Portsmouth Site, OH, for conversion. Uranium hexafluoride has been shipped safely in the United States for over 40 years by both truck and rail. Shipments of depleted UF6 would be made in accordance with all applicable transportation regulations. Shipment of depleted UF6 is regulated by the

252

Respiration-Linked Proton Transport, Changes in External pH, and Membrane Energization in Cells of Escherichia coli  

Science Journals Connector (OSTI)

...in untreated cells, and changing the atmosphere in the cuvette from N2 or Ar to air caused...1970. Acid-base titration across the plasma membrane of Micrococcus denitrifi- cans...of lactose-proton symport across the plasma membrane of Escherichia coli. Biochem...

J. Michael Gould

1979-04-01T23:59:59.000Z

253

The Metal-dependent Function of C 2?: A Conditional Membrane Domain from Protein Kinase C?  

E-Print Network [OSTI]

, and neurological disorders. Moreover, the conventional Protein Kinase Calpha (PKCalpha) has also been identified as an important molecular target in Pb2+ poisoning. Two out of three Pb^(2+) sites in full-length PKCalpha were mapped onto its C 2 domain (C 2alpha...

Morales-Rivera, Krystal A.

2013-11-26T23:59:59.000Z

254

Arabidopsis CURVATURE THYLAKOID1 Proteins Modify Thylakoid Architecture by Inducing Membrane Curvature  

Science Journals Connector (OSTI)

...assembled with the Golden Gate Shuffling method (Engler...termini. During the Golden Gate restriction-ligation...S. (2009). Golden gate shuffling: A one-pot...J. (2001). Use of red fluorescent protein from...Kirchhoff, H. , Hall, C., Wood, M., Herbstova, M...

Ute Armbruster; Mathias Labs; Mathias Pribil; Stefania Viola; Wenteng Xu; Michael Scharfenberg; Alexander P. Hertle; Ulrike Rojahn; Poul Erik Jensen; Fabrice Rappaport; Pierre Joliot; Peter Dörmann; Gerhard Wanner; Dario Leister

2013-07-09T23:59:59.000Z

255

Arabidopsis Membrane Steroid Binding Protein 1 Is Involved in Inhibition of Cell Elongation  

Science Journals Connector (OSTI)

...indicated that overexpression of MSBP1 led to reduced growth, and suppression...resulting in the expression of green fluorescent protein (GFP) fused to the C...light was provided by eight 40-W fluorescent bulbs and filtered through one layer...

Xiao-Hua Yang; Zhi-Hong Xu; Hong-Wei Xue

2004-12-17T23:59:59.000Z

256

The Herpes Simplex Virus Type 1 UL20 Protein Modulates Membrane Fusion Events during Cytoplasmic Virion Morphogenesis and Virus-Induced Cell Fusion  

Science Journals Connector (OSTI)

...Herpes Simplex Virus Type 1 UL20 Protein Modulates Membrane Fusion Events during Cytoplasmic...that affect cell fusion in herpes simplex virus type 1. Virology 132...virus-induced cell fusion. | The herpes simplex virus type 1 (HSV-1) UL20...

Timothy P. Foster; Jeffrey M. Melancon; Joel D. Baines; Konstantin G. Kousoulas

2004-05-01T23:59:59.000Z

257

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

The mechanical properties of model systems were analyzed. A reasonably accurate finite element model was implemented and a rational metric to predict the strength of ceramic/metal concentrical joints was developed. The mode of failure of the ceramic/metal joints was determined and the importance of the mechanical properties of the braze material was assessed. Thermal cycling experiments were performed on the model systems and the results were discussed. Additionally, experiments using the concept of placing diffusion barriers on the ceramic surface to limit the extent of the reaction with the braze were performed. It was also observed that the nature and morphology of the reaction zone depends greatly on the nature of the perovskite structure being used. From the experiments, it is observed that the presence of Cr in the Fe-occupied sites decreases the tendency of Fe to segregate and to precipitate out of the lattice. In these new experiments, Ni was observed to play a major role in the decomposition of the ceramic substrate.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2001-05-01T23:59:59.000Z

258

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

Conversion of natural gas to liquid fuels and chemicals is a major goal for the Nation as it enters the 21st Century. Technically robust and economically viable processes are needed to capture the value of the vast reserves of natural gas on Alaska's North Slope, and wean the Nation from dependence on foreign petroleum sources. Technologies that are emerging to fulfill this need are all based syngas as an intermediate. Syngas (a mixture of hydrogen and carbon monoxide) is a fundamental building block from which chemicals and fuels can be derived. Lower cost syngas translates directly into more cost-competitive fuels and chemicals. The currently practiced commercial technology for making syngas is either steam methane reforming (SMR) or a two-step process involving cryogenic oxygen separation followed by natural gas partial oxidation (POX). These high-energy, capital-intensive processes do not always produce syngas at a cost that makes its derivatives competitive with current petroleum-based fuels and chemicals.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2002-01-01T23:59:59.000Z

259

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

The mechanical properties of model systems were analyzed. A reasonably accurate finite element model was implemented and a rational metric to predict the strength of ceramic/metal concentrical joints was developed. The mode of failure of the ceramic/metal joints was determined and the importance of the mechanical properties of the braze material was assessed. Thermal cycling experiments were performed on the model systems and the results were discussed. Additionally, experiments using the concept of placing diffusion barriers on the ceramic surface to limit the extent of the reaction with the braze were performed. It was also observed that the nature and morphology of the reaction zone depends greatly on the nature of the perovskite structure being used. From the experiments, it is observed that the presence of Cr in the Fe-occupied sites decreases the tendency of Fe to segregate and to precipitate out of the lattice. In these new experiments, Ni was observed to play a major role in the decomposition of the ceramic substrate.

Dr. Sukumar Bandopadhyay; Dr. Nagendfra Nagabhushana

2001-07-01T23:59:59.000Z

260

Molecular modeling of the morphology and transport properties of two direct methanol fuel cell membranes: phenylated sulfonated poly(ether ether ketone ketone) versus Nafion  

SciTech Connect (OSTI)

We have used molecular dynamics simulations to examine membrane morphology and the transport of water, methanol and hydronium in phenylated sulfonated poly ether ether ketone ketone (Ph-SPEEKK) and Nafion membranes at 360 K for a range of hydration levels. At comparable hydration levels, the pore diameter is smaller, the sulfonate groups are more closely packed, the hydronium ions are more strongly bound to sulfonate groups, and the diffusion of water and hydronium is slower in Ph-SPEEKK relative to the corresponding properties in Nafion. The aromatic carbon backbone of Ph-SPEEKK is less hydrophobic than the fluorocarbon backbone of Nafion. Water network percolation occurs at a hydration level ({lambda}) of {approx}8 H{sub 2}O/SO{sub 3}{sup -}. At {lambda} = 20, water, methanol and hydronium diffusion coefficients were 1.4 x 10{sup -5}, 0.6 x 10{sup -5} and 0.2 x 10{sup -5} cm{sup 2}/s, respectively. The pore network in Ph-SPEEKK evolves dynamically and develops wide pores for {lambda} > 20, which leads to a jump in methanol crossover and ion transport. This study demonstrates the potential of aromatic membranes as low-cost challengers to Nafion for direct methanol fuel cell applications and the need to develop innovative strategies to combat methanol crossover at high hydration levels.

Devanathan, Ramaswami; Idupulapati, Nagesh B.; Dupuis, Michel

2012-08-14T23:59:59.000Z

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


261

Unique Thylakoid Membrane Architecture of a Unicellular N2-Fixing Cyanobacterium Revealed by Electron Tomography  

SciTech Connect (OSTI)

Cyanobacteria, descendants of the endosymbiont that gave rise to modern-day chloroplasts, are vital contributors to global biological energy conversion processes. A thorough understanding of the physiology of cyanobacteria requires detailed knowledge of these organisms at the level of cellular architecture and organization. In these prokaryotes, the large membrane protein complexes of the photosynthetic and respiratory electron transport chains function in the intracellular thylakoid membranes. Like plants, the architecture of the thylakoid membranes in cyanobacteria has direct impact on cellular bioenergetics, protein transport, and molecular trafficking. However, whole-cell thylakoid organization in cyanobacteria is not well understood. Here we present, by using electron tomography, an in-depth analysis of the architecture of the thylakoid membranes in a unicellular cyanobacterium, Cyanothece sp. ATCC 51142. Based on the results of three-dimensional tomographic reconstructions of near-entire cells, we determined that the thylakoids in Cyanothece 51142 form a dense and complex network that extends throughout the entire cell. This thylakoid membrane network is formed from the branching and splitting of membranes and encloses a single lumenal space. The entire thylakoid network spirals as a peripheral ring of membranes around the cell, an organization that has not previously been described in a cyanobacterium. Within the thylakoid membrane network are areas of quasi-helical arrangement with similarities to the thylakoid membrane system in chloroplasts. This cyanobacterial thylakoid arrangement is an efficient means of packing a large volume of membranes in the cell while optimizing intracellular transport and trafficking.

Liberton, Michelle L.; Austin, Jotham R.; Berg, R. H.; Pakrasi, Himadri B.

2011-04-01T23:59:59.000Z

262

Operation of staged membrane oxidation reactor systems  

SciTech Connect (OSTI)

A method of operating a multi-stage ion transport membrane oxidation system. The method comprises providing a multi-stage ion transport membrane oxidation system with at least a first membrane oxidation stage and a second membrane oxidation stage, operating the ion transport membrane oxidation system at operating conditions including a characteristic temperature of the first membrane oxidation stage and a characteristic temperature of the second membrane oxidation stage; and controlling the production capacity and/or the product quality by changing the characteristic temperature of the first membrane oxidation stage and/or changing the characteristic temperature of the second membrane oxidation stage.

Repasky, John Michael

2012-10-16T23:59:59.000Z

263

Bismuth Dimercaptopropanol (BisBAL) Inhibits the Expression of Extracellular Polysaccharides and Proteins by Brevundimonas diminuta: Implications for Membrane Microfiltration  

SciTech Connect (OSTI)

A 2:1 molar ratio preparation of bismuth with a lipophilic dithiol (3-dimercapto-1-propanol, BAL)significantly reduced extracellular polymeric substances (EPS) expression by Brevundimonas diminuta in suspended cultures at levels just below the minimum inhibitory concentration (MIC). Total polysaccharides and proteins secreted by B. diminuta decreased by approximately 95% over a 5-day period when exposed to the bismuth-BAL chelate (BisBAL) at near MIC (12 ?M). Fourier-transform infrared spectroscopy (FTIR) suggested that a possible mechanism of biofilm disruption by BisBAL is the inhibition of carbohydrate Oacetylation. FTIR also revealed extensive homology between EPS samples with and without BisBAL treatment, with proteins, polysaccharides, and peptides varying predominantly only in the amount expressed. EPS secretion decreased following BisBAL treatment as verified by atomic force microscopy and scanning electron microscopy. Without BisBAL treatment, a slime-like EPS matrix secreted by B. diminuta resulted in biofouling and inefficient hydrodynamic backwashing of microfiltration membranes.

Badireddy, Appala R.; Chellam, Shankararaman; Yanina, Svetlana; Gassman, Paul L.; Rosso, Kevin M.

2008-02-15T23:59:59.000Z

264

Adenovirus DNA Replication I. Requirement for Protein Synthesis and Isolation of Nuclear Membrane Fractions Containing Newly Synthesized Viral DNA and Proteins  

Science Journals Connector (OSTI)

...Musashimurayama, Tokyo 190-12, Japan. Nuclear membrane fractions were...000 rpm. To isolate nuclear membrane fractions by...gradient procedure, the nuclear suspension in TKM buffer...sonically disrupted at full power in a Raytheon DF-101...

Tadashi Yamashita; Maurice Green

1974-09-01T23:59:59.000Z

265

Autographa californica Nucleopolyhedrovirus Ac76: a Dimeric Type II Integral Membrane Protein That Contains an Inner Nuclear Membrane-Sorting Motif  

Science Journals Connector (OSTI)

...was generated, that expressed the fusion protein under the control of the OpMNPV...was generated in which the GFP:SM fusion protein was highly expressed under the...INM-SM with full-length Ac76, two other fusion proteins, GFP:SM1-48 (GS1-48...

Denghui Wei; Yan Wang; Xiaomei Zhang; Zhaoyang Hu; Meijin Yuan; Kai Yang

2013-11-06T23:59:59.000Z

266

Transport study of hafnium(IV) and zirconium(IV) ions mutual separation by using Tri-n-butyl phosphate-xylene-based supported liquid membranes  

SciTech Connect (OSTI)

A Hf transport study through supported liquid membranes has been carried out to determine flux and permeability data for this metal ion. Tri-n-butyl phosphate (TBP)-xylene-based liquid membranes supported in polypropylene hydrophobic microporous film have been used. These data for hafnium and the previous data for zirconium have furnished the Zr to Hf flux ratio (S) as a function of nitric acid and TBP concentrations of the order of 12 in a single stage at room temperature. Optimum conditions for the separation of these two metal ions appear to 5-6 TBP mol/dm{sup 3} HNO{sub 3}, concentrations {le} 2.93 mol/dm{sup 3}, and 10C. The value of S from an aqueous solution containing 2.4% Hf with respect to Zr has been found to be >125 at 10C and 1.78 mol/dm{sup 3} TBP concentration in the membrane. The technique appears to be feasible for purification of Zr respect to Hf or vice versa.

Chaudry, M.A.; Ahmed, B. (Pakistan Inst. of Nuclear Science and Technology, Islamabad (Pakistan))

1992-02-01T23:59:59.000Z

267

Helping Hands for Budding Prospects: ENTH/ANTH/VHS Accessory Proteins in Endocytosis, Vacuolar Transport, and Secretion  

Science Journals Connector (OSTI)

...Potsdam, 10627 Potsdam, Germany www.plantcell.org/cgi/doi/10.1105/tpc.114.131680 [W] Online version contains Web-only data. Coated vesicles provide a major mechanism for the transport of proteins through the endomembrane system of plants...

Jan Zouhar; Michael Sauer

2014-11-21T23:59:59.000Z

268

Engineering Development of Ceramic Membrane Reactor  

E-Print Network [OSTI]

ceramic Ion Transport Membrane (ITM) reactor system for low-cost conversion of natural gas to hydrogen;7 A Revolutionary Technology Using Ceramic Membranes Ion Transport Membranes (ITM) ­ Non-porous multiEngineering Development of Ceramic Membrane Reactor Systems for Converting Natural Gas to Hydrogen

269

Crystallization of Mitochondrial Respiratory Complex II fromChicken Heart: A Membrane-Protein Complex Diffracting to 2.0Angstrom  

SciTech Connect (OSTI)

Procedure is presented for preparation of diffraction-quality crystals of a vertebrate mitochondrial respiratory Complex II. The crystals have the potential to diffract to at least 2.0 Angstrom with optimization of post-crystal-growth treatment and cryoprotection. This should allow determination of the structure of this important and medically relevant membrane protein complex at near-atomic resolution and provide great detail of the mode of binding of substrates and inhibitors at the two substrate-binding sites.

Huang, Li-shar; Borders, Toni M.; Shen, John T.; Wang, Chung-Jen; Berry, Edward A.

2004-12-17T23:59:59.000Z

270

Transportation  

Science Journals Connector (OSTI)

The romantic rides in Sandburgs eagle-car changed society. On the one hand, motor vehicle transportation is an integral thread of societys fabric. On the other hand, excess mobility fractures old neighborh...

David Hafemeister

2014-01-01T23:59:59.000Z

271

Support Vector Machines A Literature Based Method for Protein  

E-Print Network [OSTI]

motility and secretion P 160 5112 Inorganic ion transport and metabolism T 97 3627 Signal transduction modification, protein turnover, chaperones M 155 4079 Cell envelope biogenesis, outer membrane N 133 3110 Cell mechanisms Metabolism C 224 5594 Energy production and conversion G 171 5262 Carbohydrate transport

272

SRP-mediated protein targeting: structure and function revisited  

Science Journals Connector (OSTI)

The signal recognition particle (SRP) and its membrane-bound receptor (SR) deliver membrane proteins and secretory proteins to the translocation channel in the plasma membrane (or the endoplasmic reticulum). The general outline of the SRP pathway is conserved in all three kingdoms of life. During the past decade, structure determination together with functional studies has brought our understanding of the SRP-mediated protein transport to an almost molecular level. An impressive amount of new information especially on the prokaryotic SRP is integrated into the current picture of the SRP pathway.

Joen Luirink; Irmgard Sinning

2004-01-01T23:59:59.000Z

273

Membrane proteomic analysis of pancreatic cancer cells  

E-Print Network [OSTI]

and amino acids, protein folding/ unfolded protein response,ER regulation of protein folding 8.98 Ketone body metabolismcatabolic process; protein folding/transport; response to

Liu, Xiaojun; Zhang, Min; Go, Vay Liang W; Hu, Shen

2010-01-01T23:59:59.000Z

274

Dlg1 in the vesicle trafficking machinery Emerging role of the scaffolding protein Dlg1 in interfacing  

E-Print Network [OSTI]

recruit components of the vesicle trafficking machinery either to the plasma membrane or to transport required for transport; GluR1, AMPA receptor subunit; Glut4, glucose transporter type 4; GUK, guanylate complexes, including receptors, ion channels and signaling proteins, at specialized zones of the plasma

Paris-Sud XI, Université de

275

Molecular Origin of Electron Paramagnetic Resonance Line Shapes on [beta]-Barrel Membrane Proteins: The Local Solvation Environment Modulates Spin-Label Configuration  

SciTech Connect (OSTI)

In this work, electron paramagnetic resonance (EPR) spectroscopy and X-ray crystallography were used to examine the origins of EPR line shapes from spin-labels at the protein-lipid interface on the {beta}-barrel membrane protein BtuB. Two atomic-resolution structures were obtained for the methanethiosulfonate spin-label derivatized to cysteines on the membrane-facing surface of BtuB. At one of these sites, position 156, the label side chain resides in a pocket formed by neighboring residues; however, it extends from the protein surface and yields a single-component EPR spectrum in the crystal that results primarily from fast rotation about the fourth and fifth bonds linking the spin-label to the protein backbone. In lipid bilayers, site 156 yields a multicomponent spectrum resulting from different rotameric states of the labeled side chain. Moreover, changes in the lipid environment, such as variations in bilayer thickness, modulate the EPR spectrum by modulating label rotamer populations. At a second site, position 371, the labeled side chain interacts with a pocket on the protein surface, leading to a highly immobilized single-component EPR spectrum that is not sensitive to hydrocarbon thickness. This spectrum is similar to that seen at other sites that are deep in the hydrocarbon, such as position 170. This work indicates that the rotameric states of spin-labels on exposed hydrocarbon sites are sensitive to the environment at the protein-hydrocarbon interface, and that this environment may modulate weak interactions between the labeled side chain and the protein surface. In the case of BtuB, lipid acyl chain packing is not symmetric around the {beta}-barrel, and EPR spectra from labeled hydrocarbon-facing sites in BtuB may reflect this asymmetry. In addition to facilitating the interpretation of EPR spectra of membrane proteins, these results have important implications for the use of long-range distance restraints in protein structure refinement that are obtained from spin-labels.

Freed, Daniel M.; Khan, Ali K.; Horanyi, Peter S.; Cafiso, David S. (UV)

2012-01-20T23:59:59.000Z

276

E-Print Network 3.0 - axonal transport proteins Sample Search...  

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

Summary: Axonal Protein Synthesis and the Regulation of Local Mitochondrial Function Barry B. Kaplan... inhibition of axonal protein synthesis markedly reduces the functional...

277

Gas transport properties of reverse-selective poly(ether-b-amide6)/[Emim][BF4] gel membranes for CO2/light gases separation  

Science Journals Connector (OSTI)

Abstract The present research investigates deeply effect of 1-ethyl-3 methylimidazolium tetrafluoroborate ([Emim][BF4]) ionic liquid on separation performance and transport properties of poly(ether-b-amide6)(Pebax1657) at different operating pressures from 2 to 20 bar and temperatures from 25 to 65C. [Emim][BF4] showed interesting separation factor for CO2/light gases as a solvent and it was expected that its addition to Pebax1657 leads more amorphous structure, thereby diffusion and permeability of gases increase. [Emim][BF4] was added to the polymer solution up to 100 wt.% of Pebax1657 weight and permeation coefficients of CO2, H2, CH4 and N2 through the prepared membranes were measured. The results showed remarkable increment in permeation of all the tested gases, particularly CO2 and ideal selectivity of CO2/H2 enhanced significantly due to high solubility selectivity of the added compound. Effect of operating conditions on solubility coefficients were also investigated, thus sorption isotherms and activation energies of permeability, solubility and diffusion were calculated. In addition, the membranes were characterized by SEM, DSC, FT-IR spectroscopy and Tensile analysis to inspect changes in their physical and thermal properties, precisely.

Hesamoddin Rabiee; Ali Ghadimi; Toraj Mohammadi

2014-01-01T23:59:59.000Z

278

Studies on the in situ electrooxidation and selective permeation of cerium(IV) across a bulk liquid membrane containing tributyl phosphate as the ion transporter  

SciTech Connect (OSTI)

The results of experiments carried out to develop a liquid membrane (LM) technique for the extractive permeation of cerium from nitric acid solutions are described. In-situ electrooxidation of Ce{sup 3+} to extractable Ce{sup 4+} and its transport across bulk LM (BLM) composed of tri-n-butyl phosphate (TBP)/dodecane mixtures was systematically studied under varied hydrodynamical and chemical conditions. The permeability of metal ions across the BLM was dependent on the efficiency of extraction, ionic activity of feed solutions, stirring rate, composition of the receiving phase, etc. The transport rates were found to vary linearly (a log-log correlation) with the cation concentration in feed solutions and concentration of TBP in BLM. A permeation velocity equation for cerium ion through the membrane has been proposed. More than 90% permeation of Ce with a maximum flux of 8.63 x 10{sup {minus}5} mol/m{sup 2}/s could be accomplished under the experimental conditions: stirring rates at feed and strip solutions were 380 and 300 rpm, respectively; feed was 1 mol/dm{sup 3} of HNO{sub 3} containing 0.005 mol/dm{sup 3} Ce(NO{sub 3}){sub 3}; LM contained 30% TBP/dodecane; and the receiving phase was distilled water. Radiochemically pure Ce-144 was partitioned from the Ce-Am mixture obtained by extraction chromatographic fractioning of high level radioactive waste. This also resulted in the purification of Am-241 in the feed solution with a decontamination factor of {approximately} 12 from Ce.

Kedari, C.S.; Pandit, S.S.; Ramanujam, A. [Bhabha Atomic Research Centre, Trombay (India). Fuel Reprocessing Div.] [Bhabha Atomic Research Centre, Trombay (India). Fuel Reprocessing Div.

1999-06-01T23:59:59.000Z

279

Salt Concentration Differences Alter Membrane Resistance in Reverse Electrodialysis Stacks  

E-Print Network [OSTI]

,3,4 Selective transport of ions through the membranes creates an electric potential across pairs of AEMs by changing the membrane polymer chemistry and/or membrane form factor.9-13 The ion transport properties on either side of the membrane on ion transport properties must be studied to improve our under- standing

280

The role of transmembrane domains in membrane fusion  

Science Journals Connector (OSTI)

Biological membrane fusion is driven by different types of molecular fusion machines. Most of these proteins are membrane ... . SNARE proteins are essential for intracellular membrane fusion along the secretory a...

D. Langosch; M. Hofmann; C. Ungermann

2007-04-01T23:59:59.000Z

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


281

MEMBRANE FUNCTION, Part 2. Passive Movement: Diffusion, Osmosis, and Gibbs-Donnan Equilibrium 1  

E-Print Network [OSTI]

such as ion gradients or sunlight. I. Passive transport Passive transport is diffusion through a membrane of the membrane. This movement is entirely by the process of diffusion (to be covered below) · ions and polar. Mechanisms of Membrane Transport There are two general modes of transport across membranes: passive transport

Prestwich, Ken

282

A Discussion of Conductivity Testing in High Temperature Membranes...  

Broader source: Energy.gov (indexed) [DOE]

A Discussion of Conductivity Testing in High Temperature Membranes (lessons learned in assessing transport) A Discussion of Conductivity Testing in High Temperature Membranes...

283

Transportation  

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

Due to limited parking, all visitors are strongly encouraged to: Due to limited parking, all visitors are strongly encouraged to: 1) car-pool, 2) take the Lab's special conference shuttle service, or 3) take the regular off-site shuttle. If you choose to use the regular off-site shuttle bus, you will need an authorized bus pass, which can be obtained by contacting Eric Essman in advance. Transportation & Visitor Information Location and Directions to the Lab: Lawrence Berkeley National Laboratory is located in Berkeley, on the hillside directly above the campus of University of California at Berkeley. The address is One Cyclotron Road, Berkeley, California 94720. For comprehensive directions to the lab, please refer to: http://www.lbl.gov/Workplace/Transportation.html Maps and Parking Information: On Thursday and Friday, a limited number (15) of barricaded reserved parking spaces will be available for NON-LBNL Staff SNAP Collaboration Meeting participants in parking lot K1, in front of building 54 (cafeteria). On Saturday, plenty of parking spaces will be available everywhere, as it is a non-work day.

284

Topical Review Fluctuations and Fractal Noise in Biological Membranes  

E-Print Network [OSTI]

and transport of ions and molecules across biological membranes. We know that ion transport through mem- branes in electrical properties associated with cell membrane ion transport. Key words: Brownian motion -- Cell membrane elec- trical properties -- Fractals -- Gaussian noise -- Ion transport -- Nonlinear dynamics

285

The evolutionary origin of the protein-translocating channel of chloroplastic envelope membranes: Identification of a cyanobacterial homolog  

Science Journals Connector (OSTI)

...required surface protein or a protein whose cytoplasmic accumulation is lethal. The latter effect has been observed with PilE in PilC-insertional mutants deficient in pili assembly (45) and is even more plausible with channel proteins secreting virulence...

Sigrun Reumann; Jennifer Davila-Aponte; Kenneth Keegstra

1999-01-01T23:59:59.000Z

286

Autotransporters: The Cellular Environment Reshapes a Folding Mechanism to Promote Protein Transport  

E-Print Network [OSTI]

the cellular environment affects protein folding mechanisms. Here, we focus on one unique aspect affect protein folding kinetics and the conformations of folding intermediates? We focus on recent have been made to understand the mechanisms by which proteins fold to their native conformations.3

Clark, Patricia L.

287

Crystal structure of a concentrative nucleoside transporter from Vibrio cholerae at 2.4;#8201;  

SciTech Connect (OSTI)

Nucleosides are required for DNA and RNA synthesis, and the nucleoside adenosine has a function in a variety of signalling processes. Transport of nucleosides across cell membranes provides the major source of nucleosides in many cell types and is also responsible for the termination of adenosine signalling. As a result of their hydrophilic nature, nucleosides require a specialized class of integral membrane proteins, known as nucleoside transporters (NTs), for specific transport across cell membranes. In addition to nucleosides, NTs are important determinants for the transport of nucleoside-derived drugs across cell membranes. A wide range of nucleoside-derived drugs, including anticancer drugs (such as Ara-C and gemcitabine) and antiviral drugs (such as zidovudine and ribavirin), have been shown to depend, at least in part, on NTs for transport across cell membranes. Concentrative nucleoside transporters, members of the solute carrier transporter superfamily SLC28, use an ion gradient in the active transport of both nucleosides and nucleoside-derived drugs against their chemical gradients. The structural basis for selective ion-coupled nucleoside transport by concentrative nucleoside transporters is unknown. Here we present the crystal structure of a concentrative nucleoside transporter from Vibrio cholerae in complex with uridine at 2.4 {angstrom}. Our functional data show that, like its human orthologues, the transporter uses a sodium-ion gradient for nucleoside transport. The structure reveals the overall architecture of this class of transporter, unravels the molecular determinants for nucleoside and sodium binding, and provides a framework for understanding the mechanism of nucleoside and nucleoside drug transport across cell membranes.

Johnson, Zachary Lee; Cheong, Cheom-Gil; Lee, Seok-Yong (Duke)

2012-07-11T23:59:59.000Z

288

Identifying Calcium Channels and Porters in Plant Membranes  

SciTech Connect (OSTI)

The overall objectives of the proposal submitted in 6/90 was to understand how Ca was transported across plant membranes, and how these transport pathways were regulated. Ca participates in many cellular processes, including the transduction of hormonal and environmental signals, secretion, and protein folding. These processes depend on the coordination of passive Ca fluxes via channels and active Ca pumps; however these transport pathways are poorly understood in plants. We had, therefore, proposed to identify and characterize Ca transport proteins, such as the inositol-1 ,4,5-trisphosphate (IP3)-sensitive Ca channels and Ca pumps. We have had difficulties characterizing and cloning the IP3-sensitive Ca channel, but have made considerable progress on the biochemical characterization, and partial purification of a 120 kD Ca-pumping ATPase. We have begun to determine the structure of Ca pumps by molecular cloning and have already obtained a partial cDNA with features characteristic of Ca pumps.

Sze, Heven

1998-04-01T23:59:59.000Z

289

Contribution of the drug transporter ABCG2 (breast cancer resistance protein) to resistance against anticancer nucleosides  

Science Journals Connector (OSTI)

...apical membrane before it can be pumped out, thereby setting up a...in a chemoimmunity defense system. Physiol Rev 2006;86:1179-236...indicating a role in mediator storage. Blood 2004;104:3603-10...produced in three model expression systems. Mol Pharmacol 2006;69...

Cornelia de Wolf; Robert Jansen; Hiroaki Yamaguchi; Marcel de Haas; Koen van de Wetering; Jan Wijnholds; Jos Beijnen; and Piet Borst

2008-09-01T23:59:59.000Z

290

On a novel rate theory for transport in narrow ion channels and its application to the study of flux optimization via geometric effects  

E-Print Network [OSTI]

On a novel rate theory for transport in narrow ion channels and its application to the study passage time to describe single-ion conduction in narrow, effectively one-dimensional membrane channels. DOI: 10.1063/1.3077205 I. INTRODUCTION Ion channels are membrane proteins which enable se- lected ions

Reingruber, Jürgen

291

Ninth International Workshop on Plant Membrane Biology  

SciTech Connect (OSTI)

This report is a compilation of abstracts from papers which were discussed at a workshop on plant membrane biology. Topics include: plasma membrane ATP-ases; plant-environment interactions, membrane receptors; signal transduction; ion channel physiology; biophysics and molecular biology; vaculor H+ pumps; sugar carriers; membrane transport; and cellular structure and function.

Not Available

1993-12-31T23:59:59.000Z

292

Single Quantum Dot Tracking Reveals that an Individual Multivalent HIV-1 Tat Protein Transduction Domain Can Activate Machinery for Lateral Transport and Endocytosis  

Science Journals Connector (OSTI)

...microtubule-guided motors or diffusion. Two-color...the cortical network. Future studies are needed to...cells utilizing single-quantum dot tracking (SQT...transport of HER2 by motor proteins in living cells...proteins labeled with quantum dots. Exp. Cell Res...

Yasuhiro Suzuki; Chandra Nath Roy; Warunya Promjunyakul; Hiroyasu Hatakeyama; Kohsuke Gonda; Junji Imamura; Biju Vasudevanpillai; Noriaki Ohuchi; Makoto Kanzaki; Hideo Higuchi; Mitsuo Kaku

2013-06-03T23:59:59.000Z

293

Directional Transport by Nonprocessive Motor Proteins on Fascin-Cross-Linked Actin Arrays  

Science Journals Connector (OSTI)

motors, in particular motor proteins, are ideally suited to introduce chem. ... The movement of actin-myosin biomolecular linear motor under AC electric fields: An experimental study ...

Yongkuk Lee; Parviz Famouri

2013-07-02T23:59:59.000Z

294

Structural Basis of Efficient Electron Transport between Photosynthetic Membrane Proteins and Plastocyanin in Spinach Revealed Using Nuclear Magnetic Resonance  

Science Journals Connector (OSTI)

...energy is converted into the chemical energy of ATP and NADPH, are essential for almost...Solubilized PSI and cyt b 6 f were prepared from market spinach as reported previously, with...PSI enables the efficient use of light energy. In the Pc-cyt b(6)f and Pc-PSI...

Takumi Ueda; Naoko Nomoto; Masamichi Koga; Hiroki Ogasa; Yuuta Ogawa; Masahiko Matsumoto; Pavlos Stampoulis; Koji Sode; Hiroaki Terasawa; Ichio Shimada

2012-10-02T23:59:59.000Z

295

Regulation of Yeast H+-ATPase by Protein Kinases Belonging to a Family Dedicated to Activation of Plasma Membrane Transporters  

Science Journals Connector (OSTI)

...cations, including sodium, lithium, manganese, tetramethylammonium...exhibited reduced uptake of lithium and methylammonium. Ptk2 and...concentrations from 0.8 to 6 mM and an excess Mg over ATP of 5 mM (). The...the tolerance to sodium and lithium caused by the ptk2 mutation...

Alain Goossens; Natalia de la Fuente; Javier Forment; Ramon Serrano; Francisco Portillo

2000-10-01T23:59:59.000Z

296

E-Print Network 3.0 - anthocyanin transport proteins Sample Search...  

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

frequently and in large amounts can be transported... is expressed as KY 97,03. 12;82 Subcritical water and carbonated water extraction of anthocyanins from grape Source: Brye,...

297

Development of protein based bioremediation and drugs for heavy metal toxicity  

SciTech Connect (OSTI)

Structural studies were performed on several proteins of the bacterial detoxification system. These proteins are responsible for binding (MerP) and transport of heavy metals, including mercury, across membranes. The structural information obtained from NMR experiments provides insight into the selectivity and sequestration processes towards heavy metal toxins.

Opella, Stanley J.

2001-09-18T23:59:59.000Z

298

Design, purification and characterization of a soluble variant of the integral membrane protein MotB for structural studies  

Science Journals Connector (OSTI)

...using the known scattering of water as previously described...To facilitate the protein purification via affinity chromatography...presented the rational design, purification and characterization of the water-soluble variant of homodimeric...

2013-01-01T23:59:59.000Z

299

Futile cycling at the plasma membrane: a hallmark of  

E-Print Network [OSTI]

. Transport systems catalyzing ion influx across the plasma membrane of root cells fall into two broadFutile cycling at the plasma membrane: a hallmark of low-affinity nutrient transport Dev T. Britto-affinity transport systems in the plasma membranes of root cells. In this Opinion article, we illustrate that for six

Britto, Dev T.

300

Journal of Membrane Science 239 (2004) 1726 Highly conductive ordered heterogeneous ion-exchange membranes  

E-Print Network [OSTI]

in the matrix required for reasonable ion transport through the membrane is 50­70 wt.% [2Journal of Membrane Science 239 (2004) 17­26 Highly conductive ordered heterogeneous ion-exchange membranes are used in electrodialysis (ED) as ion-selective membranes and in power sources (such as fuel

Freger, Viatcheslav "Slava"

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


301

Overdamped thermal ratchets in one and more dimensions. Kinesin transport and protein folding  

E-Print Network [OSTI]

The overdamped thermal ratchet driven by an external (Orstein-Uhlenbeck) noise is revisited. The ratchet we consider is unbounded in space and not necessarily periodic . We briefly discuss the conditions under which current is obtained by analyzing the corresponding Fokker-Planck equation and its lack of stationary states. Next, two examples in more than one dimension and related to biological systems are presented. First, a two-dimensional model of a ``kinesin protein'' on a ``microtubule'' is analyzed and, second, we suggest that a ratchet mechanism may be behind the folding of proteins; the latter is elaborated with a multidimensional ratchet model.

Ernesto Gonzalez-Candela; Victor Romero-Rochin

2006-05-26T23:59:59.000Z

302

Essential Function of Protein 4.1G in Targeting of Membrane Protein Palmitoylated 6 into Schmidt-Lanterman Incisures in Myelinated Nerves  

Science Journals Connector (OSTI)

...microtubules (48) and kinesin motor proteins (2). Although...to SLI. However, a future temporal and spatial...past, present, and future. Blood 112 : 3939-3948...kidney and spleen by quantum dot injection with in...autoinhibition of kinesin-3 motor GAKIN/KIF13B. Biochemistry...

Nobuo Terada; Yurika Saitoh; Nobuhiko Ohno; Masayuki Komada; Sei Saitoh; Elior Peles; Shinichi Ohno

2011-10-24T23:59:59.000Z

303

Molecular Characterization of the PEND Protein, a Novel bZIP Protein Present in the Envelope Membrane That Is the Site of Nucleoid Replication in Developing Plastids  

Science Journals Connector (OSTI)

...migrates as a 130-kD polypeptide during lithium dodecyl sulfate (LDS)-PAGE and binds...Bedford, MA). The protein was analyzed by lithium dodecyl sulfate (LDS)-PAGE and then...as indicated. x8 indicates eightfold excess over the probe. Plus and minus signs...

Naoki Sato; Kimihisa Ohshima; Ai Watanabe; Niji Ohta; Yoshitaka Nishiyama; Jacques Joyard; Roland Douce

304

A subset of membrane-associated proteins is ubiquitinated in response to mutations in the endoplasmic reticulum degradation machinery  

Science Journals Connector (OSTI)

...Equivalent amounts (0.025% total) of input (lane 2), flow-through (lane 3...conjugates. An equivalent amount of input from the npl4-1-negative control...required for protein translocation and nuclear fusion SSA2 No Cytoplasm/Ribosome/Vacuolar...

Amy L. Hitchcock; Kathryn Auld; Steven P. Gygi; Pamela A. Silver

2003-01-01T23:59:59.000Z

305

Novel Thylakoid Membrane GreenCut Protein CPLD38 Impacts Accumulation of the Cytochrome b6f Complex and  

E-Print Network [OSTI]

for Science, Stanford, California 94305, the ¶ Howard Hughes Medical Institute, Department of Plant reinhardtii does not grow on minimal medium, is high light-sensitive under photohetero- trophic conditions (1, 2). Crystal structures now exist for the four major protein com- plexes involved in light

306

C2-Domain Abscisic Acid-Related Proteins Mediate the Interaction of PYR/PYL/RCAR Abscisic Acid Receptors with the Plasma Membrane and Regulate Abscisic Acid Sensitivity in Arabidopsis  

Science Journals Connector (OSTI)

...figures in this article are displayed in color online but in black and white in the print edition. [W] Online version contains Web-only data. Subcellular localization of abscisic acid receptors as peripheral proteins in the plasma membrane is mediated in...

Lesia Rodriguez; Miguel Gonzalez-Guzman; Maira Diaz; Americo Rodrigues; Ana C. Izquierdo-Garcia; Marta Peirats-Llobet; Maria A. Fernandez; Regina Antoni; Daniel Fernandez; Jose A. Marquez; Jose M. Mulet; Armando Albert; Pedro L. Rodriguez

2014-12-02T23:59:59.000Z

307

Nuclear Transport of the Major Capsid Protein Is Essential for Adeno-Associated Virus Capsid Formation  

Science Journals Connector (OSTI)

...the importance of the nuclear localization of the capsid proteins, we fused the nuclear localization signal of...is necessary only for nuclear transfer of the capsid...Tamai, MBL, Nagoya, Japan). Analysis of VLP formation...5 min at the maximum power of a handheld sonicator...

Mainul Hoque; Ken-ichiro Ishizu; Akiko Matsumoto; Song-Iee Han; Fumio Arisaka; Makoto Takayama; Kenji Suzuki; Kenzo Kato; Tadahito Kanda; Hajime Watanabe; Hiroshi Handa

1999-09-01T23:59:59.000Z

308

Small-molecule mimics of an a-helix for efficient transport of proteins into cells  

E-Print Network [OSTI]

­57) of HIV-1 Tat, the third helix of antennapedia homeodomain (penetratin)3,4 and designed variants was galvanized by a report6 on the ability of HIV-1 Tat fusion proteins to deliver b-galactosi- dase to multiple

Cai, Long

309

Diffusion through Carbon Nanotube Semipermeable membranes  

SciTech Connect (OSTI)

The goal of this project is to measure transport through CNTs and study effects of confinement at molecular scale. This work is motivated by several simulation papers in high profile journals that predict significantly higher transport rates of gases and liquids through carbon nanotubes as compared with similarly-sized nanomaterials (e.g. zeolites). The predictions are based on the effects of confinement, atomically smooth pore walls and high pore density. Our work will provide the first measurements that would compare to and hopefully validate the simulations. Gas flux is predicted to be >1000X greater for SWNTs versus zeolitesi. A high flux of 6-30 H2O/NT/ns {approx} 8-40 L/min for a 1cm{sup 2} membrane is also predicted. Neutron diffraction measurements indicate existence of a 1D water chain within a cylindrical ice sheet inside carbon nanotubes, which is consistent with the predictions of the simulation. The enabling experimental platform that we are developing is a semipermeable membrane made out of vertically aligned carbon nanotubes with gaps between nanotubes filled so that the transport occurs through the nanotubes. The major challenges of this project included: (1) Growth of CNTs in the suitable vertically aligned configuration, especially the single wall carbon nanotubes; (2) Development of a process for void-free filling gaps between CNTs; and (3) Design of the experiments that will probe the small amounts of analyte that go through. Knowledge of the behavior of water upon nanometer-scale confinement is key to understanding many biological processes. For example, the protein folding process is believed to involve water confined in a hydrophobic environment. In transmembrane proteins such as aquaporins, water transport occurs under similar conditions. And in fields as far removed as oil recovery and catalysis, an understanding of the nanoscale molecular transport occurring within the nanomaterials used (e.g. zeolites) is the key to process optimization. Furthermore, advancement of many emerging nanotechnologies in chemistry and biology will undoubtedly be aided by an understanding confined water transport, particularly the details of hydrogen bonding and solvation that become crucial on this length scale. We can envision several practical applications for our devices, including desalination, gas separations, dialysis, and semipermeable fabrics for protection against CW agents etc. The single wall carbon nanotube membranes will be the key platform for applications because they will allow high transport rates of small molecules such as water and eliminate solvated ions or CW agents.

Bakajin, O

2006-02-13T23:59:59.000Z

310

Folding and Function of Proteorhodopsins in Photoenergy Transducing Membranes  

SciTech Connect (OSTI)

The overall research objectives are to develop proteorhodopsin (PR) proteins as a model system for {alpha}?-helical membrane protein insertion and folding, and to advance understanding of the diversity and mechanisms of PRs, a large family of photoenergy transducers (~4000 identified) abundant in the worlds oceans. Specific aims are: (1) To develop a highefficiency genetic selection procedure for light-driven proton-pumping in E. coli cells. Such a procedure would provide a positive selection method for proper folding and function of PRs in the E. coli membrane. (2) Characterize flash-induced absorption changes and photocurrents in PR variants in organisms from various environments, and their expression level and function when expressed in E. coli. Subaims are to: (a) elucidate the relationship of the transport mechanism to mechanisms of other microbial rhodopsins, some of which like PRs function as ion transporters and some of which use light energy to activate signaling pathways (sensory rhodopsins); and (b) identify important residues and chemical events in light-driven proton transport by PRs. In addition to their importance to the energy of the biosphere PRs have attracted interest for their potential for use in making photoenergy-transducing membranes for bioengineering applications.

Spudich, John L

2012-08-10T23:59:59.000Z

311

Charged mosaic membrane prepared from microsphere gel and its characterization  

Science Journals Connector (OSTI)

A charged mosaic membrane with parallel array of different negative and positive charges was prepared from microsphere gel. Several characteristics on the novel membrane were investigated through experiments concerning transport studies, membrane potentials and membrane resistance. From analysis of the volume flux and salt flux, preferential salt transport across the charged mosaic membrane was suggested. Membrane potential did not indicate a constant value and the absolute value decreased rapidly in short time. The large time dependence supported the interpretation on salt flow in transport studies. From potential measurement, cationic and anionic transport numbers in membrane also were determined to t?K+=0.41 and t?Cl?=0.59. Membrane resistance of this mosaic membrane indicated slightly higher values than that of ordinary charged membrane.

Akira Yamauchi; Junko Tateyama; Ban-ichiroh Etoh; Minoru Takizawa; Yoshifumi Sugito; Seiji Doi

2000-01-01T23:59:59.000Z

312

Solid-state membrane module  

DOE Patents [OSTI]

Solid-state membrane modules comprising at least one membrane unit, where the membrane unit has a dense mixed conducting oxide layer, and at least one conduit or manifold wherein the conduit or manifold comprises a dense layer and at least one of a porous layer and a slotted layer contiguous with the dense layer. The solid-state membrane modules may be used to carry out a variety of processes including the separating of any ionizable component from a feedstream wherein such ionizable component is capable of being transported through a dense mixed conducting oxide layer of the membrane units making up the membrane modules. For ease of construction, the membrane units may be planar.

Gordon, John Howard (Salt Lake City, UT); Taylor, Dale M. (Murray, UT)

2011-06-07T23:59:59.000Z

313

Membranes, methods of making membranes, and methods of separating gases using membranes  

DOE Patents [OSTI]

Membranes, methods of making membranes, and methods of separating gases using membranes are provided. The membranes can include at least one hydrophilic polymer, at least one cross-linking agent, at least one base, and at least one amino compound. The methods of separating gases using membranes can include contacting a gas stream containing at least one of CO.sub.2, H.sub.2S, and HCl with one side of a nonporous and at least one of CO.sub.2, H.sub.2S, and HCl selectively permeable membrane such that at least one of CO.sub.2, H.sub.2S, and HCl is selectively transported through the membrane.

Ho, W. S. Winston

2012-10-02T23:59:59.000Z

314

Proteins  

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

Proteins Proteins Scientists manipulate and mimic proteins for use in creating solutions for medicine, sustainable energy, and more Read caption + Los Alamos National Laboratory graduate student, Patricia Langan, changes the properties of a green fluorescent protein in order to create new fluorescent protein variants. Overview of Research and Highlights Scientists at Los Alamos apply a unique collection of tools and expertise to gain a comprehensive understanding of the structure and function of proteins as well as to manipulate and mimic proteins for use in research. This knowledge can lead to a multitude of possibilities, such as enhancing cellulose degradation for biofuels based on understanding the enzymes that naturally degrade it (cellulases) or creating new therapeutics for tuberculosis patients.

315

Neurotransmitter Transporters  

E-Print Network [OSTI]

at specialized synaptic junctions where electrical excitability in the form of an action potential is translated membrane of neurons and glial cells. Transporters harness electrochemical gradients to force the movement.els.net #12;The response produced when a transmitter interacts with its receptors, the synaptic potential

Bergles, Dwight

316

Hydroxyl Ion Migration, Chemical Reactions, Water Transport and Other Effects As Optimizing Parameters In Cross-, Co- And Countercurrently Operated Membrane Cells For The Chlor/Alkali Electrolysis  

Science Journals Connector (OSTI)

A mathematical model describing a chloralkali-electrolysis in membrane cells including unusual flow pattern is presented. This paper discusses several influences like chemical reactions in the anolyte compartm...

K. H. Simmrock

1984-01-01T23:59:59.000Z

317

A Role for the Membrane in Regulating Chlamydomonas Flagellar Length  

E-Print Network [OSTI]

to the old flagellar proteins? Axonemal components can be recycled to form new flagella [55] and some cilia may recycle membrane by endocytosis [42]. However, algal and mammalian cilia also shed membrane from their tips [1], [44][46] and data reported here... is shed from flagellar tips, the lack of membrane resupply may stimulate the flagellar disassembly reported here. Inhibition of secretion should affect both protein and membrane delivery to flagella. CX, a protein synthesis inhibitor, inhibits protein...

Dentler, William L., Jr

2013-01-24T23:59:59.000Z

318

Charged Amino Acids (R83, E567, D617, E625, R669, and K678) of CusA Are Required for Metal Ion Transport in the Cus Efflux System  

SciTech Connect (OSTI)

Gram-negative bacteria expel various toxic chemicals via tripartite efflux pumps belonging to the resistance-nodulation-cell division superfamily. These pumps span both the inner and outer membranes of the cell. The three components of these tripartite systems are an inner-membrane, substrate-binding transporter (or pump); a periplasmic membrane fusion protein (or adaptor); and an outer-membrane-anchored channel. These three efflux proteins interact in the periplasmic space to form the three-part complexes. We previously presented the crystal structures of both the inner-membrane transporter CusA and membrane fusion protein CusB of the CusCBA tripartite efflux system from Escherichia coli. We also described the co-crystal structure of the CusBA adaptor-transporter, revealing that the trimeric CusA efflux pump assembles with six CusB protein molecules to form the complex CusB{sub 6}-CusA{sub 3}. We here report three different conformers of the crystal structures of CusBA-Cu(I), suggesting a mechanism on how Cu(I) binding initiates a sequence of conformational transitions in the transport cycle. Genetic analysis and transport assays indicate that charged residues, in addition to the methionine pairs and clusters, are essential for extruding metal ions out of the cell.

Su, Chih-Chia; Long, Feng; Lei, Hsiang-Ting; Reddy Bolla, Jani; Do, Sylvia V.; Rajashankar, Kanagalaghatta R.; Yu, Edward W. (Cornell); (Iowa State)

2012-10-23T23:59:59.000Z

319

Staged membrane oxidation reactor system  

DOE Patents [OSTI]

Ion transport membrane oxidation system comprising (a) two or more membrane oxidation stages, each stage comprising a reactant zone, an oxidant zone, one or more ion transport membranes separating the reactant zone from the oxidant zone, a reactant gas inlet region, a reactant gas outlet region, an oxidant gas inlet region, and an oxidant gas outlet region; (b) an interstage reactant gas flow path disposed between each pair of membrane oxidation stages and adapted to place the reactant gas outlet region of a first stage of the pair in flow communication with the reactant gas inlet region of a second stage of the pair; and (c) one or more reactant interstage feed gas lines, each line being in flow communication with any interstage reactant gas flow path or with the reactant zone of any membrane oxidation stage receiving interstage reactant gas.

Repasky, John Michael; Carolan, Michael Francis; Stein, VanEric Edward; Chen, Christopher Ming-Poh

2012-09-11T23:59:59.000Z

320

Staged membrane oxidation reactor system  

DOE Patents [OSTI]

Ion transport membrane oxidation system comprising (a) two or more membrane oxidation stages, each stage comprising a reactant zone, an oxidant zone, one or more ion transport membranes separating the reactant zone from the oxidant zone, a reactant gas inlet region, a reactant gas outlet region, an oxidant gas inlet region, and an oxidant gas outlet region; (b) an interstage reactant gas flow path disposed between each pair of membrane oxidation stages and adapted to place the reactant gas outlet region of a first stage of the pair in flow communication with the reactant gas inlet region of a second stage of the pair; and (c) one or more reactant interstage feed gas lines, each line being in flow communication with any interstage reactant gas flow path or with the reactant zone of any membrane oxidation stage receiving interstage reactant gas.

Repasky, John Michael; Carolan, Michael Francis; Stein, VanEric Edward; Chen, Christopher Ming-Poh

2014-05-20T23:59:59.000Z

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


321

Staged membrane oxidation reactor system  

DOE Patents [OSTI]

Ion transport membrane oxidation system comprising (a) two or more membrane oxidation stages, each stage comprising a reactant zone, an oxidant zone, one or more ion transport membranes separating the reactant zone from the oxidant zone, a reactant gas inlet region, a reactant gas outlet region, an oxidant gas inlet region, and an oxidant gas outlet region; (b) an interstage reactant gas flow path disposed between each pair of membrane oxidation stages and adapted to place the reactant gas outlet region of a first stage of the pair in flow communication with the reactant gas inlet region of a second stage of the pair; and (c) one or more reactant interstage feed gas lines, each line being in flow communication with any interstage reactant gas flow path or with the reactant zone of any membrane oxidation stage receiving interstage reactant gas.

Repasky, John Michael; Carolan, Michael Francis; Stein, VanEric Edward; Chen, Christopher Ming-Poh

2013-04-16T23:59:59.000Z

322

Proteins  

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

Bioscience: Bioenergy, Biosecurity, and Health » Bioscience: Bioenergy, Biosecurity, and Health » Proteins Protein Engineering, Structure, and Function Los Alamos scientists seek a comprehensive understanding of the structure and function of proteins which can lead to a multitude of possibilities, such as enhancing cellulose degradation for biofuels or creating new therapeutics. Get Expertise Cliff Unkefer Director, Protein Crystallography Station Email Tom Terwilliger Laboratory Fellow Email Andrew Bradbury Bioscience Group Leader Email Rebecca McDonald Bioscience Communications Email Los Alamos scientists are developing mosaic proteins that may one day become the first viable vaccine that can protect humans from HIV, the virus that causes AIDS. Scientists manipulate and mimic proteins for use in creating solutions for

323

A unified model of electroporation and molecular transport  

E-Print Network [OSTI]

Biological membranes form transient, conductive pores in response to elevated transmembrane voltage, a phenomenon termed electroporation. These pores facilitate electrical and molecular transport across cell membranes that ...

Smith, Kyle Christopher

2011-01-01T23:59:59.000Z

324

Intrinsically Disordered Proteins and Their Environment: Effects of Strong Denaturants, Temperature, pH, Counter Ions, Membranes, Binding Partners, Osmolytes, and Macromolecular Crowding  

Science Journals Connector (OSTI)

Intrinsically disordered proteins (IDPs) differ from normal ordered proteins at several levels, structural, functional and ... is complementary to the catalytic activities of ordered proteins. Amino acid biases...

Vladimir N. Uversky

2009-10-01T23:59:59.000Z

325

YidC protein, a molecular chaperone for LacY protein folding via the SecYEG protein machinery  

E-Print Network [OSTI]

GroEL-GroES- mediated protein folding. Chem. Rev. 106, 1917of chaperone-mediated protein folding in the cytosol. Nat.that impair membrane protein folding and generate a membrane

Zhu, L; Kaback, HR; Dalbey, RE

2013-01-01T23:59:59.000Z

326

Production of permeable cellulose triacetate membranes  

DOE Patents [OSTI]

A phase inversion process for the preparation of cellulose triacetate (CTA) and regenerated cellulose membranes is disclosed. Such membranes are useful as supports for liquid membranes in facilitated transport processes, as microfiltration membranes, as dialysis or ultrafiltration membranes, and for the preparation of ion-selective electrodes. The process comprises the steps of preparing a casting solution of CTA in a solvent comprising a mixture of cyclohexanone and methylene chloride, casting a film from the casting solution, and immersing the cast film in a methanol bath. The resulting CTA membrane may then be hydrolyzed to regenerated cellulose using conventional techniques.

Johnson, B.M.

1986-12-23T23:59:59.000Z

327

Production of permeable cellulose triacetate membranes  

DOE Patents [OSTI]

A phase inversion process for the preparation of cellulose triacetate (CTA) and regenerated cellulose membranes is disclosed. Such membranes are useful as supports for liquid membranes in facilitated transport processes, as microfiltration membranes, as dialysis or ultrafiltration membranes, and for the preparation of ion-selective electrodes. The process comprises the steps of preparing a casting solution of CTA in a solvent comprising a mixture of cyclohexanone and methylene chloride, casting a film from the casting solution, and immersing the cast film in a methanol bath. The resulting CTA membrane may then be hydrolyzed to regenerated cellulose using conventional techniques.

Johnson, Bruce M. (Bend, OR)

1986-01-01T23:59:59.000Z

328

THE VITELLINE MEMBRANE OF THE UNFERTILIZED HEN'S EGG  

E-Print Network [OSTI]

membrane is charged and asymmetrical. It's directional specificity to ion transport and accompanying volumeTHE VITELLINE MEMBRANE OF THE UNFERTILIZED HEN'S EGG : ELECTROLYTE AND WATER TRANSPORT T. RYMEN J more than just the result of the membrane's ion exchange behaviour and that it may involve an enzymatic

Paris-Sud XI, Université de

329

Supporting Information for: Salt concentration differences alter membrane  

E-Print Network [OSTI]

). The membrane area available for ion transport was 11.4 cm2 . Platinum mesh electrodes that spanned the crossS1 Supporting Information for: Salt concentration differences alter membrane resistance in reverse-814-867-1847 #12;S2 Membrane resistance measurement Without a concentration difference Membrane resistance

330

Phosphatidylethanolamine mediates insertion of the catalytic domain of leader peptidase in membranes  

E-Print Network [OSTI]

: Leader peptidase; Membrane protein; Protein-lipid interaction; Protein secretion and Lipid Enzymology, Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht vesicles and vesicles composed of purified inner membrane lipids with comparable efficiency. It is shown

Paetzel, Mark

331

Membrane asymmetry in epithelia: is the tight junction a barrier to diffusion in the plasma membrane?  

Science Journals Connector (OSTI)

... Leaf, A. in Membrane Transport in Biology Vol. 3 (eds Giebisch, G., Tosteson, D. C. & Ussing, H. H.) 126 (Springer, Berlin, ... Palomo, A. in Membrane Transport in Biology Vol. 3 (eds Giebisch, G., Tosteson, D. C. & Ussing H. H.) 2753 (Springer, Berlin, ...

Paul R. Dragsten; Robert Blumenthal; Joseph S. Handler

1981-12-24T23:59:59.000Z

332

Genetic Analysis of Arabidopsis Mutants Impaired in Plastid Lipid Import Reveals a Role of Membrane Lipids in Chloroplast Division  

SciTech Connect (OSTI)

The biogenesis of photosynthetic membranes in plants relies largely on lipid import from the endoplasmic reticulum (ER) and this lipid transport process is mediated by TGD proteins in Arabidopsis. Such a dependency of chloroplast biogenesis on ER-to-plastid lipid transport was recently exemplified by analyzing double mutants between tgd1-1 or tgd4-3 and fad6 mutants. The fad6 mutants are defective in the desaturation of membrane lipids in chloroplasts and therefore dependent on import of polyunsaturated lipid precursors from the ER for constructing a competent thylakoid membrane system. In support of a critical role of TGD proteins in ER-to-plastid lipid trafficking, we showed that the introduction of the tgd mutations into fad6 mutant backgrounds led to drastic reductions in relative amounts of thylakoid lipids. Moreover, the tgd1-1 fad6 and tgd4-3 fad6 double mutants were deficient in polyunsaturated fatty acids in chloroplast membrane lipids, and severely compromised in the biogenesis of photosynthetic membrane systems. Here we report that these double mutants are severely impaired in chloroplast division. The possible role of membrane lipids in chloroplast division is discussed.

Fan, J.; Xu, C.

2011-03-01T23:59:59.000Z

333

E-Print Network 3.0 - apical membrane antigen Sample Search Results  

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

network (TGN) to apical membrane delivery... of newly synthesized proteins and lipids to differentiated apical and basolateral plasma membrane domains... 4KIII inhibits...

334

The Arabidopsis Chaperone J3 Regulates the Plasma Membrane H+-ATPase through Interaction with the  

E-Print Network [OSTI]

membrane H+-ATPase (PM H+-ATPase) plays an important role in the regulation of ion and metabolite transport inactivation of the PKS5 kinase. INTRODUCTION In both plants and fungi, transport across the plasma membrane constitutes a driving force for the transport of solutes and metab- olites across the plasma membrane

Deng, Xing-Wang

335

Novel Targeting Signals Mediate the Sorting of Different Isoforms of the Tail-Anchored Membrane Protein Cytochrome b5 to Either Endoplasmic Reticulum or Mitochondria  

Science Journals Connector (OSTI)

...system (e.g., Golgi, vacuole, plasma membrane, etc.). It is now well established...antibodies in hybridoma medium (clone 9E10; Princeton University, Monoclonal Antibody Facility, Hybridoma, Princeton, NJ); rabbit anti-E1beta (Luethy...

Yeen Ting Hwang; Scott M. Pelitire; Matthew P.A. Henderson; David W. Andrews; John M. Dyer; Robert T. Mullen

2004-10-14T23:59:59.000Z

336

Microporous Inorganic Membranes for Hydrogen Purification  

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

Microporous Microporous Inorganic Membranes for Hydrogen Purification Brian L. Bischoff, Roddie R. Judkins, and Timothy R. Armstrong Oak Ridge National Laboratory Presented at: DOE Workshop on Hydrogen Separations and Purification Technologies Arlington, Virginia September 8, 2004 2 OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY Hydrogen Separation Membranes * Non-Porous - Palladium based films - Ion transport membranes * Porous - Ordered microporous membranes (IUPAC Recommendations 2001), e.g. zeolite membranes - Microporous membranes 3 OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY Microporous Membranes * IUPAC defines micropores as pores smaller than 2nm in diameter * Generally a microporous membrane is made by applying 1 to 3 thin layers to a porous support * Porous support can be ceramic or metallic

337

Substrate-induced changes in the structural properties of LacY  

E-Print Network [OSTI]

speed limit for protein folding measured by structure membrane protein folding membrane transport

2014-01-01T23:59:59.000Z

338

Applications of evolutionary SVM to prediction of membrane alpha-helices  

Science Journals Connector (OSTI)

This paper is in the area of membrane proteins. Membrane proteins make up about 75% of possible targets for novel drugs discovery. However, membrane proteins are one of the most understudied groups of proteins in biochemical research because of technical ... Keywords: Alpha-helix transmembrane domain, Genetic algorithm, Support vector machine

Hassan B. Kazemian; Kenneth White; Dominic Palmer-Brown

2013-07-01T23:59:59.000Z

339

Compounds having aromatic rings and side-chain amide-functionality and a method for transporting monovalent anions across biological membranes using the same  

DOE Patents [OSTI]

A compound containing at least two aromatic rings covalently bonded together, with each aromatic ring containing at least one oxyacetamide-based side chain, the compound being capable of forming a chloride ion channel across a lipid bilayer, and transporting chloride ion across the lipid bilayer.

Davis, Jeffery T. (College Park, MD); Sidorov, Vladimir (Richmond, VA); Kotch, Frank W. (New Phila., PA)

2008-04-08T23:59:59.000Z

340

9 - Microporous silica membranes: fundamentals and applications in membrane reactors for hydrogen separation  

Science Journals Connector (OSTI)

Abstract: This chapter discusses the research and development of membrane reactors, incorporating microporous silica-based membranes, specifically for hydrogen production. Microporous silica membranes are first introduced alongside a discussion of relevant gas transport mechanisms, membrane performance parameters, membrane reactor designs and membrane reactor performance metrics. This is followed by an in-depth analysis of the various research investigations where silica membrane reactors have been used to produce hydrogen and/or syngas from hydrocarbon reforming reactions. Of particular importance here is the hydrothermal instability of silica-based membranes at the required operating temperatures and so the chapter closes by presenting the future research trends and industrial design challenges and considerations of silica-based membrane reactors.

S. Smart; J. Beltramini; J.C. Diniz da Costa; S.P. Katikaneni; T. Pham

2013-01-01T23:59:59.000Z

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


341

Biomolecular transport and separation in nanotubular networks.  

SciTech Connect (OSTI)

Cell membranes are dynamic substrates that achieve a diverse array of functions through multi-scale reconfigurations. We explore the morphological changes that occur upon protein interaction to model membrane systems that induce deformation of their planar structure to yield nanotube assemblies. In the two examples shown in this report we will describe the use of membrane adhesion and particle trajectory to form lipid nanotubes via mechanical stretching, and protein adsorption onto domains and the induction of membrane curvature through steric pressure. Through this work the relationship between membrane bending rigidity, protein affinity, and line tension of phase separated structures were examined and their relationship in biological membranes explored.

Stachowiak, Jeanne C.; Stevens, Mark Jackson (Sandia National Laboratories, Albuquerque, NM); Robinson, David B.; Branda, Steven S.; Zendejas, Frank; Meagher, Robert J.; Sasaki, Darryl Yoshio; Bachand, George David (Sandia National Laboratories, Albuquerque, NM); Hayden, Carl C.; Sinha, Anupama; Abate, Elisa; Wang, Julia; Carroll-Portillo, Amanda (Sandia National Laboratories, Albuquerque, NM); Liu, Haiqing (Sandia National Laboratories, Albuquerque, NM)

2010-09-01T23:59:59.000Z

342

Mechanistic aspects of photoconversion at semiconductor-liquid junctions and in facilitated transport membranes. Final report, March 15, 1994--March 14, 1998  

SciTech Connect (OSTI)

A major portion of the research completed during this funding period involved the use of rotating ring-disk electrochemical techniques in conjunction with carefully chosen solution redox systems to investigate hot electron transfer reactions at the semiconductor electrolyte interface. This paper cover the following topics: photoreduction reactions at GaAs/AlGaAs superlattice electrodes; photoelectrochemistry at GaInP{sub 2} capped p-GaAs electrodes; further investigation of p-InP photocathodes; rotating ring disk photoelectrochemistry at TiO{sub 2} films; and photomodulation of interfacial mass transport rates.

Koval, C.A.

1998-06-01T23:59:59.000Z

343

FY08 MEMBRANE CHARACTERIZATION REPORT FOR HYBRID SULFUR ELECTROLYZER  

SciTech Connect (OSTI)

This report summarizes results from all of the membrane testing completed to date at the Savannah River National Laboratory (SRNL) for the sulfur dioxide-depolarized electrolyzer (SDE). Several types of commercially-available membranes have been analyzed for ionic resistance and sulfur dioxide transport including perfluorinated sulfonic acid (PFSA), sulfonated polyether-ketone-ketone (SPEKK), and polybenzimidazole membranes (PBI). Of these membrane types, the poly-benzimidazole membrane, Celtec-L, exhibited the best combination of characteristics for use in an SDE. Several experimental membranes have also been analyzed including hydrated sulfonated Diels-Alder polyphenylenes (SDAPP) membranes from Sandia National Laboratory, perfluorosulfonimide (PFSI) and sulfonated perfluorocyclobutyl aromatic ether (S-PFCB) prepared by Clemson University, hydrated platinum-treated PFSA prepared by Giner Electrochemical Systems (GES) and Pt-Nafion{reg_sign} 115 composites prepared at SRNL. The chemical stability, SO{sub 2} transport and ionic conductivity characteristics have been measured for several commercially available and experimental proton-conducting membranes. Commercially available PFSA membranes such as the Nafion{reg_sign} series exhibited excellent chemical stability and ionic conductivity in sulfur dioxide saturated sulfuric acid solutions. Sulfur dioxide transport in the Nafion{reg_sign} membranes varied proportionally with the thickness and equivalent weight of the membrane. Although the SO{sub 2} transport in the Nafion{reg_sign} membranes is higher than desired, the excellent chemical stability and conductivity makes this membrane the best commercially-available membrane at this time. Initial results indicated that a modified Nafion{reg_sign} membrane incorporating Pt nanoparticles exhibited significantly reduced SO{sub 2} transport. Reduced SO{sub 2} transport was also measured with commercially available PBI membrane and several experimental membranes produced at SNL and Clemson. These membranes also exhibit good chemical stability and conductivity in concentrated sulfuric acid solutions and, thus, serve as promising candidates for the SDE. Therefore, we recommend further testing of these membranes including electrolyzer testing to determine if the reduced SO{sub 2} transport eliminates the formation of sulfur-containing films at the membrane/cathode interface. SO{sub 2} transport measurements in the custom built characterization cell identified experimental limitations of the original design. During the last quarter of FY08 we redesigned and fabricated a new testing cell to overcome the previous limitations. This cell also offers the capability to test membranes under polarized conditions as well as test the performance of MEAs under selected electrolyzer conditions.

Hobbs, D; Hector Colon-Mercado, H; Mark Elvington, M

2008-09-01T23:59:59.000Z

344

Structural and Functional Proteomic Analysis of a Developing Energy Transducing Membrane  

SciTech Connect (OSTI)

While much is known about the light reactions of photosynthesis in purple bacteria, comparatively little information is available on how the requisite integral membrane proteins are assembled, their patterns of cellular localization are established or their apoproteins cooperate with numerous assembly factors in their insertion into the growing intracytoplasmic membrane (ICM). This problem was approached through a detailed structural and functional proteomic analysis of ICM assembly process in the well-characterized purple bacterium Rhodobacter sphaeroides. Proteomic approaches have focused upon identification of membrane proteins temporally expressed during ICM development and spatially localized in both membrane growth initiation sites and in mature ICM vesicles. Protocols were established for ICM induction under reduced aeration and ICM remodeling in cells adapting to low intensity illumination, which permitted isolation, in sucrose density gradients, of ICM growth initiation sites as an upper pigmented band (UPB) and mature ICM vesicles as the main (chromatophore) band. Non-denaturing clear native gel electrophoresis (CNE) of these isolated membrane fractions gave rise to pigmented bands containing the peripheral light-harvesting 2 (LH2) antenna and the reaction center-light-harvesting 1 (RC-LH1) core complex, together with a full array of other ICM proteins, which were subjected to proteomic analysis. Proteomic analysis of the gel bands from chromatophores revealed developmental changes including increasing levels of the LH2 complex as ICM development proceeded, as well as a large array of other associated proteins including high spectral counts for the F1FOâ?? ATP synthase subunits, given the inability to detect this coupling factor, as well as the more abundant cytochrome bc1 complex by atomic force microscopy (AFM). Significant levels of general membrane assembly factors were encountered, as well as high counts for RSP6124, a protein of unknown function, correlated with increasing LH2 levels. RC-LH1-containing CNE gel bands from the UPB were enriched in cytoplasmic membrane (CM) markers, including electron transfer and transport proteins, as well as general membrane assembly factors relative to chromatophore bands. This confirms the origin of the UPB from both peripheral respiratory membrane and sites of CM invagination. Significant levels of preprotein translocases YidC, YajC and SecY, bacterial type 1 signal peptidase and twin arg translocation subunit TatA were found. Such general membrane assembly factors were significantly enriched in the UPB RC-LH1 gel bands, confirming the active role of membrane invagination sites in pigment-protein complex assembly. Functional correlates of proteomics approaches were provided by near-IR fluorescence induction/relaxation transients arising from LH-BChl components. A linear relation was found between increasing functional absorption cross-section and slowing of RC electron transfer turnover rate, thought to arise from the imposition of constraints upon free UQ diffusion between the RC and cytochrome bc1 complex as the membrane became saturated with new LH2 rings. In cells undergoing ICM induction in which generation of the electrochemical proton gradient was uncoupled with CCCP, blockage in membrane insertion of the LH and RC polypetides was demonstrated. This was reflected in a diminution of quantum yield of the primary charge separation, a cessation in expansion of functional absorption cross-section and a >4-fold slowing in RC electron transfer turnover. The ICM insertion of ATP synthase and transhydrogenase was also significantly diminished. Importantly, for the UPB fraction, CCCP treatment resulted in accumulation of ~2-fold greater levels of the preprotein translocase SecY, the SecA translocation ATPase, Sec D and SecF insertion components, and chaperonins DnaJ and DnaK, suggesting that these general membrane assembly factors had accumulated in association with nascent LH and RC assembly intermediates. In addition to spectrally homogeneous bands c

Niederman, Robert A

2012-06-04T23:59:59.000Z

345

Protein kinesis: The dynamics of protein trafficking and stability  

SciTech Connect (OSTI)

The purpose of this conference is to provide a multidisciplinary forum for exchange of state-of-the-art information on protein kinesis. This volume contains abstracts of papers in the following areas: protein folding and modification in the endoplasmic reticulum; protein trafficking; protein translocation and folding; protein degradation; polarity; nuclear trafficking; membrane dynamics; and protein import into organelles.

NONE

1995-12-31T23:59:59.000Z

346

Amphiphiles for protein solubilization and stabilization  

DOE Patents [OSTI]

The invention provides amphiphiles for manipulating membrane proteins. The amphiphiles can feature carbohydrate-derived hydrophilic groups and branchpoints in the hydrophilic moiety and/or in a lipophilic moiety. Such amphiphiles are useful as detergents for solubilization and stabilization of membrane proteins, including photosynthetic protein superassemblies obtained from bacterial membranes.

Gellman, Samuel Helmer; Chae, Pil Seok; Laible, Phillip D; Wander, Marc J

2014-11-04T23:59:59.000Z

347

6 Ion Transport, Osmoregulation, and  

E-Print Network [OSTI]

177 6 Ion Transport, Osmoregulation, and Acid­Base Balance W.S. Marshall and M. Grosell CONTENTS I)............................................................................182 5. Skin and Opercular Membrane..................................................................................................183 2. Sea-Water Transport Mode -- Na+,K+-ATPase and Na+,K+, 2Cl­ Co-transport

Grosell, Martin

348

Hybrid membrane/cryogenic separation of oxygen from air for use in the oxy-fuel process  

E-Print Network [OSTI]

and high temperature ion transport membranes. While polymeric membranes can produce oxygen enriched air of various concentrations, ion transport membranes can produce purities of close to 100%. Both membraHybrid membrane/cryogenic separation of oxygen from air for use in the oxy-fuel process Thomas

Struchtrup, Henning

349

Ionically Conducting Membranes for Hydrogen Production and Separation  

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

IONICALLY CONDUCTING MEMBRANES IONICALLY CONDUCTING MEMBRANES FOR HYDROGEN PRODUCTION AND SEPARATION Presented by Tony Sammells Eltron Research Inc. Boulder, Colorado www.eltronresearch.com Presented at DOE Hydrogen Separations Workshop Arlington, Virginia September 8, 2004 ELTRON RESEARCH INC. TO BE DISCUSSED * Membranes for Hydrogen Production - Compositions - Feedstocks - Performance - Key Technical Hurdles * Membranes for Hydrogen Separation - Compositions - Ex Situ vs. In Situ WGS - Performance - Key Technical Hurdles ELTRON RESEARCH INC. OVERALL SCHEME FOR CONVERTING FEEDSTOCK TO HYDROGEN WITH SIMULTANEOUS CARBON DIOXIDE SEQUESTRATION Oxygen Transport Membrane Hydrogen Transport Membrane Natural Gas Coal Biomass Syngas CO/H 2 WGS H 2 O CO 2 /H 2 1618afs.dsf H 2 CO 2 ELTRON RESEARCH INC. INCENTIVES FOR OXYGEN TRANSPORT MEMBRANES FOR

350

Membrane magic  

SciTech Connect (OSTI)

The Kansas Power and Light Co.'s La Cyne generating station has found success with membrane filtration water pretreatment technology. The article recounts the process followed in late 2004 to install a Pall Aria 4 microfilter in Unit 1 makeup water system at the plant to produce cleaner water for reverse osmosis feed. 2 figs., 2 photos.

Buecker, B. [Kansas City Power and Light Co. (United States)

2005-09-01T23:59:59.000Z

351

Minor Antenna Proteins CP24 and CP26 Affect the Interactions between Photosystem II Subunits and the Electron Transport Rate in Grana Membranes of Arabidopsis  

Science Journals Connector (OSTI)

...content per leaf area compared with wild-type plants in regular lighting, but koCP24/26 showed a small decrease in chlorophyll content...for the use of the EM facility at the University of Verona Medical Center. We also thank J. Lavergne (Commissariat a lEnergie...

Silvia de Bianchi; Luca Dall'Osto; Giuseppe Tognon; Tomas Morosinotto; Roberto Bassi

2008-04-01T23:59:59.000Z

352

Minor Antenna Proteins CP24 and CP26 Affect the Interactions between Photosystem II Subunits and the Electron Transport Rate in Grana Membranes of Arabidopsis  

Science Journals Connector (OSTI)

...quantified (n 4) using the GelPro 3.2 software (Bio-Rad). To avoid any deviation...illumination, and PAR the photosynthetic active radiations (white light, measured as mumol m2...333-359. Niyogi, K.K. (2000). Safety valves for photosynthesis. Curr. Opin...

Silvia de Bianchi; Luca Dall'Osto; Giuseppe Tognon; Tomas Morosinotto; Roberto Bassi

2008-04-01T23:59:59.000Z

353

A Novel Cl Inward-Rectifying Current in the Plasma Membrane of the Calcifying Marine Phytoplankton  

E-Print Network [OSTI]

as much as 40% of annual global carbon assimilation. Ion and nutrient transport across the plasma membrane revealed a dominant anion conductance in response to membrane hyperpolarization. Ion substitution showed conductances play an essential role in membrane voltage regulation that relates to the unique transport

Taylor, Alison

354

Neutron Reflectivity Study of Lipid Membranes Assembled on Ordered Nanocomposite and Nanoporous Silica Thin  

E-Print Network [OSTI]

moleculestrappedwithinthenanocompositethinfilmmay be used to detect trans-membrane transport (e.g., ion channel function). Furthermore, the ability in facilitating molecular transport across the membrane plane. In this regard, the use of ultrathin polymericNeutron Reflectivity Study of Lipid Membranes Assembled on Ordered Nanocomposite and Nanoporous

Parikh, Atul N.

355

Mitochondrial potassium transport: the K+ Keith D. Garlid*, Petr Paucek  

E-Print Network [OSTI]

; Ion channel gating; Membrane transport; Volume regulation 1. Introduction The inner membrane. This means that ion traffic across the inner membrane will be very high. Moreover, the gradients driving saltReview Mitochondrial potassium transport: the K+ cycle Keith D. Garlid*, Petr Paucek Department

Garlid, Keith

356

ITM Syngas and ITM H2: Engineering Development of Ceramic Membrane Reactor Systems for  

E-Print Network [OSTI]

(U.S. DOE) and other members of the ITM Syngas/ITM H2 Team, is developing Ion Transport Membrane (ITM of the ITM membrane to oxygen ions, which diffuse through the membrane under a chemical potential gradientITM Syngas and ITM H2: Engineering Development of Ceramic Membrane Reactor Systems for Converting

357

Processing and intracellular localization of rice stripe virus Pc2 protein in insect cells  

SciTech Connect (OSTI)

Rice stripe virus (RSV) belongs to the genus Tenuivirus and its genome consists of four single-stranded RNAs encoding seven proteins. Here, we have analyzed the processing and membrane association of Pc2 encoded by vcRNA2 in insect cells. The enhanced green fluorescent protein (eGFP) was fused to the Pc2 and used for the detection of Pc2 fusion proteins. The results showed that Pc2 was cleaved to produce two proteins named Pc2-N and Pc2-C. When expressed alone, either Pc2-N or Pc2-C could transport to the Endoplasmic reticulum (ER) membranes independently. Further mutagenesis studies revealed that Pc2 contained three ER-targeting domains. The results led us to propose a model for the topology of the Pc2 in which an internal signal peptide immediately followed a cleavage site, and two transmembrane regions are contained.

Zhao, Shuling; Zhang, Gaozhan; Dai, Xuejuan; Hou, Yanling; Li, Min [College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009 (China)] [College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009 (China); Liang, Jiansheng, E-mail: jsliang@yzu.edu.cn [College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009 (China)] [College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009 (China); Liang, Changyong, E-mail: cyliang@yzu.edu.cn [College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009 (China)] [College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009 (China)

2012-08-01T23:59:59.000Z

358

A Plant Homolog of the Neutrophil NADPH Oxidase gp91phox Subunit Gene Encodes a Plasma Membrane Protein with Ca2+ Binding Motifs  

Science Journals Connector (OSTI)

...16-hr-light/8-hr-dark cycle or in continuous...reaction (PCR) cycles, respectively...mCi/L Amersham Life Science, Arlington...the protein blot analysis of this fraction...R.W. Rain-, wind-, and touch-induced...M. Segal A.W. Analysis of glycosylation...

Thomas Keller; Howard G. Damude; Dietrich Werner; Peter Doerner; Richard A. Dixon; Chris Lamb

359

Genomic reduction and evolution of novel genetic membranes and protein-targeting machinery in eukaryote-eukaryote chimaeras (meta-algae)  

Science Journals Connector (OSTI)

...symbiogenesis and protein targeting nuclear genes means they cost much less in resources to replicate...cell size and the amount of nuclear DNA is not regulation of genes...to me, however, that the graph of nuclear volume and DNA content versus...

2003-01-01T23:59:59.000Z

360

The effects of storage time on vitelline membrane protein banding patterns and interior egg quality of eggs from non-molted and molted hens  

E-Print Network [OSTI]

and stored (4C) per experiment. Three eggs were evaluated on days 0, 7, 14, 21, 28, 35, and 42 for eggs from pre-molted hens; and 1, 7, 14, 21, 28, 35, and 42 for eggs from molted hens for changes in SDS-PAGE protein banding patterns. The yolk from each...

Kelley, Angela Jean

2004-09-30T23:59:59.000Z

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


361

Membrane Binding and Subcellular Localization of Retroviral Gag Proteins Are Differentially Regulated by MA Interactions with Phosphatidylinositol-(4,5)-Bisphosphate and RNA  

Science Journals Connector (OSTI)

...1016/S0969-2126(02)00896-1 . 66. Arnold K , Bordoli L, Kopp J and Schwede T. 2006. The SWISS-MODEL workspace: a web-based environment for protein structure homology modelling. Bioinformatics 22 :195-201. doi: 10.1093/bioinformatics...

Jingga Inlora; David R. Collins; Marc E. Trubin; Ji Yeon J. Chung; Akira Ono

2014-12-01T23:59:59.000Z

362

Structural and Functional Characterization of Ybr137wp Implicates Its Involvement in the Targeting of Tail-Anchored Proteins to Membranes  

Science Journals Connector (OSTI)

...1.3r1. Schrodinger LLC, New York, NY. 42. Kelley, LA , and MJ Sternberg. 2009. Protein structure prediction on the Web: a case study using the Phyre server. Nat. Protoc. 4 :363-371. doi: 10.1038/nprot.2009.2 . 43. Winzeler, EA...

Yi-Hung Yeh; Tai-Wen Lin; Yi-Chuan Li; Jung-Yu Tung; Cheng-Yuan Lin; Chwan-Deng Hsiao

2014-10-06T23:59:59.000Z

363

Identification and functional characterization of lipid binding proteins in liver and adipose tissues of Gallus domesticus  

E-Print Network [OSTI]

; whereas the second hepatic lipid transport protein is most likely liver-FABP (L-FABP). An FABP from chicken adipose cytosol (A-FABP) was purified by membrane ultrafiltration and molecular sieve chromatography. Purification was verified by SDS... via ion exchange chromatography, pH 7. 73. Purification was verified by ligand binding assays and SDS-PAGE. The first protein eluted (designated ns-LTP) had a molecular weight of approximately 14. 5 kDa and the second protein (designated L...

Sams, Gretchen Hubler

1990-01-01T23:59:59.000Z

364

Thermodynamics and Structure of Peptide-Aggregates at Membrane Surfaces  

E-Print Network [OSTI]

Thermodynamics and Structure of Peptide- Aggregates at Membrane Surfaces INAUGURALDISSERTATION zur. Introduction 01 1.1 ­ Thermodynamics of Protein Aggregation 01 1.2 ­ Formation of Protein Aggregates 03 1 and P-glycoprotein: Connecting Thermodynamics and Membrane Structure with Functional Activity 23 3

Quake, Stephen R.

365

Living cells are delimited by the lipid bilayer membrane, which separates an internal environment from a drastic  

E-Print Network [OSTI]

. As this region is extremely thin (around 27 ?), the membrane potential translates into an intense electric field of the cell and to harness the membrane electric field, so the embedded membrane proteins must sense changes separation across the membrane, which trans lates into a membrane potential that is on the order of ­100 m

Bezanilla, Francisco

366

Structure of ABC Transporter MsbA in Complex with ATP Vi and  

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

ABC Transporter MsbA ABC Transporter MsbA in Comlex with ATP Vi and Lipopolysaccharide: Implications for Lipid Flipping Christopher L. Reyes and Geoffrey Chang* Department of Molecular Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd. CB105, La Jolla, CA 92137 ATP-binding cassette (ABC) transporters are integral membrane proteins critical for the transport of a wide variety of substrate molecules across the cell membrane. MsbA, along with human MDR1 P-glycoprotein, are members of the ABC transporter family that have been implicated in multidrug resistance by coupling ATP binding and hydrolysis to substrate transport. This drug efflux results in resistance to antibiotics in microorganisms and resistance to chemotherapeutic drugs in human cancer cells1. Using x-ray diffraction data collected at SSRL Beam Line 11-1 and ALS, we have determined the 4.2 Å x-ray crystal structure of MsbA in complex with transition state mimic ADP, vanadate (an analog of the g phosphate of ATP) and the human immunomodulatory substrate Ra lipopolysaccharide. This structure is the first intact ABC transporter in complex with nucleotide and substrate.

367

Membrane-patch Excision  

Science Journals Connector (OSTI)

Mechanical manipulation of the cell using glass micropipettes that leads to the extraction of a narrow region of cell membrane. The excision can lead to an isolated membrane patch in which the side of the membran...

2009-01-01T23:59:59.000Z

368

Proton conducting ceramic membranes for hydrogen separation  

DOE Patents [OSTI]

A multi-phase proton conducting material comprising a proton-conducting ceramic phase and a stabilizing ceramic phase. Under the presence of a partial pressure gradient of hydrogen across the membrane or under the influence of an electrical potential, a membrane fabricated with this material selectively transports hydrogen ions through the proton conducting phase, which results in ultrahigh purity hydrogen permeation through the membrane. The stabilizing ceramic phase may be substantially structurally and chemically identical to at least one product of a reaction between the proton conducting phase and at least one expected gas under operating conditions of a membrane fabricated using the material. In a barium cerate-based proton conducting membrane, one stabilizing phase is ceria.

Elangovan, S. (South Jordan, UT); Nair, Balakrishnan G. (Sandy, UT); Small, Troy (Midvale, UT); Heck, Brian (Salt Lake City, UT)

2011-09-06T23:59:59.000Z

369

Membrane cleaning in membrane bioreactors: A review  

Science Journals Connector (OSTI)

Abstract Membrane bioreactors (MBRs) have been widely used in wastewater treatment and reclamation. Membrane cleaning is an essential part during the operation of \\{MBRs\\} since membrane fouling is an unavoidable problem. In past decades, with the in-depth understanding on membrane fouling, significant advances in membrane cleaning have been achieved. However, a comprehensive review on membrane cleaning in \\{MBRs\\} is still lacking. This paper attempts to critically review the recent developments of membrane cleaning. Firstly, the fouling and cleaning fundamentals are addressed, and then a comprehensive review on physical, chemical, and biological/biochemical cleaning is presented. The procedures of determining proper cleaning protocols for MBR systems are also proposed. Finally, the existing challenges and future research efforts are discussed in order to ensure the development of membrane cleaning toward a more effective and sustainable way in MBRs.

Zhiwei Wang; Jinxing Ma; Chuyang Y. Tang; Katsuki Kimura; Qiaoying Wang; Xiaomeng Han

2014-01-01T23:59:59.000Z

370

Membranes for corrosive oxidations. Final CRADA report.  

SciTech Connect (OSTI)

The objective of this project is to develop porous hydrophilic membranes that are highly resistant to oxidative and corrosive conditions and to deploy them for recovery and purification of high tonnage chemicals such as hydrogen peroxide and other oxychemicals. The research team patented a process for membrane-based separation of hydrogen peroxide (US Patent No. 5,662,878). The process is based on using a hydrophilic membrane to separate hydrogen peroxide from the organic working solution. To enable this process, a new method for producing hydrophilic membrane materials (Patent No.6,464,880) was reported. We investigated methods of producing these hydrophilic materials and evaluated separations performance in comparison to membrane stability. It was determined that at the required membrane flux, membrane stability was not sufficient to design a commercial process. This work was published (Hestekin et al., J. Membrane Science 2006). To meet the performance needs of the process, we developed a membrane contactor method to extract the hydrogen peroxide, then we surveyed several commercial and pre-commercial membrane materials. We identified pre-commercial hydrophilic membranes with the required selectivity, flux, and stability to meet the needs of the process. In addition, we invented a novel reaction/separations format that greatly increases the performance of the process. To test the performance of the membranes and the new formats we procured and integrated reactor/membrane separations unit that enables controlled mixing, flow, temperature control, pressure control, and sampling. The results were used to file a US non-provisional patent application (ANL-INV 03-12). Hydrogen peroxide is widely used in pulp and paper applications, environmental treatment, and other industries. Virtually all hydrogen peroxide production is now based on a process featuring catalytic hydrogenation followed by auto-oxidation of suitable organic carrier molecules. This process has several drawbacks, particularly in the extraction phase. One general disadvantage of this technology is that hydrogen peroxide must be produced at large centralized plants where it is concentrated to 70% by distillation and transported to the users plant sites where it is diluted before use. Advanced membranes have the potential to enable more efficient, economic, and safe manufacture of hydrogen peroxide. Advanced membrane technology would allow filtration-based separation to replace the difficult liquid-liquid extraction based separation step of the hydrogen peroxide process. This would make it possible for hydrogen peroxide to be produced on-site in mini-plants at 30% concentration and used at the same plant location without distillation and transportation. As a result, production could become more cost-effective, safe and energy efficient.

Snyder, S. W.; Energy Systems

2010-02-01T23:59:59.000Z

371

New possibilities of electroinduced membrane gas and vapor separation  

SciTech Connect (OSTI)

A novel membrane technique to effect electroinduced facilitated transport of neutral molecules in ion-exchange membranes was suggested. Experiments have been carried out with platinum-coated Nafion membranes in Cu{sup 2+}/Cu{sup 1+} form. This may be a potential technique for the separation of olefin/paraffin mixtures. It was shown that by applying an electric current to the membrane the permeability of ethylene increased 6-fold, compared to the permeability of the initial Pt-coated membrane without current.

Bessarabov, D.G.; Sanderson, R.D. [Univ. of Stellenbosch (South Africa). Inst. for Polymer Science] [Univ. of Stellenbosch (South Africa). Inst. for Polymer Science; Valuev, V.V.; Popkov, Y.M.; Timashev, S.F. [Karpov Inst. of Physical Chemistry, Moscow (Russian Federation)] [Karpov Inst. of Physical Chemistry, Moscow (Russian Federation)

1997-06-01T23:59:59.000Z

372

Microcomposite Fuel Cell Membranes  

Broader source: Energy.gov [DOE]

Summary of microcomposite fuel cell membrane work presented to the High Temperature Membrane Working Group Meeting, Orlando FL, October 17, 2003

373

Membrane-Transistor Cable  

Science Journals Connector (OSTI)

Membrane-Transistor Cable ... The system is the basis for a development of bioelectronic transducers and for the study of nonlinear phenomena in membrane cables. ...

Marion Rentschler; Peter Fromherz

1998-01-20T23:59:59.000Z

374

Reaction-Driven Ion Transport Membrane  

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

Jenny B. Tennant Jenny B. Tennant Gasification Technology Manager National Energy Technology Laboratory 3610 Collins Ferry Road P.O. Box 880 Morgantown, WV 26507-0880 304-285-4830 jenny.tennant@netl.doe.gov Susan Maley Project Manager National Energy Technology Laboratory 3610 Collins Ferry Road P.O. Box 880 Morgantown, WV 26507-0880 304-285-1321 susan.maley@netl.doe.gov David Studer Principal Investigator Air Products and Chemicals Inc.

375

Unique Thylakoid Membrane Architecture of aUnicellular N2-Fixing...  

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

intracellular transport and trafficking. Citation: Liberton ML, JR Austin, RH Berg, and HB Pakrasi.2011."Unique Thylakoid Membrane Architecture of aUnicellular N2-Fixing...

376

Amino acids evoke short-latency membrane conductance increase in pancreatic acinar cells  

Science Journals Connector (OSTI)

... K. J. in Membrane Transport in Biology Vol. IV (eds Giebisch, G., Tosteson, D. C. & Ussing, H. H.) 811852 (Springer, Berlin, ...

N. Iwatsuki; O. H. Petersen

1980-01-31T23:59:59.000Z

377

E-Print Network 3.0 - anion selective membrane Sample Search...  

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

potential... Development of synthetic membrane transporters for anions ... Source: Smith, Bradley D. - Department of Chemistry and Biochemistry, University of Notre Dame...

378

High performance and antifouling vertically aligned carbon nanotube membrane for water purification  

Science Journals Connector (OSTI)

Abstract A vertically aligned carbon nanotube (VA CNT) membrane created from the successful fusion of nanotechnology and membrane technology has been stated to be a next generation membrane due to its fast water transport and antimicrobial properties. Although previous studies of the VA CNT membrane reported the potential for fast water transport or desalination by molecular dynamics simulation, this study is the first to report on the feasibility of using the VA CNT membrane for water purification. The VA CNT membrane (4.8nm of pore diameter and 6.81010#/cm2 of pore density) was fabricated and its flux, rejection performance, and membrane biofouling tendency were evaluated in comparison to the commercial ultrafiltration (UF) membrane. The VA CNT membrane appeared to have a water flux approximately three times higher than the UF membrane and water transport approximately 70,000 times faster than conventional no-slip flow. This higher flux was peculiarly observed in water, the most hydrophilic solvent, while other solvents showed that permeate flux decreased with higher viscosity. The rejection property of the VA CNT membrane as examined by the MWCO measurement was similar to the commercial UF membrane. Additionally, the VA CNT membrane showed better biofouling resistance with approximately 15% less permeate flux reduction and 2log less bacterial attachment than the UF membrane. This study reports the high potential of the VA CNT membrane with antifouling property in the water purification process.

Youngbin Baek; Cholin Kim; Dong Kyun Seo; Taewoo Kim; Jeong Seok Lee; Yong Hyup Kim; Kyung Hyun Ahn; Sang Seek Bae; Sang Cheol Lee; Jaelim Lim; Kyunghyuk Lee; Jeyong Yoon

2014-01-01T23:59:59.000Z

379

Active membrane having uniform physico-chemically functionalized ion channels  

DOE Patents [OSTI]

The present invention relates to a physicochemically-active porous membrane for electrochemical cells that purports dual functions: an electronic insulator (separator) and a unidirectional ion-transporter (electrolyte). The electrochemical cell membrane is activated for the transport of ions by contiguous ion coordination sites on the interior two-dimensional surfaces of the trans-membrane unidirectional pores. One dimension of the pore surface has a macroscopic length (1 nm-1000 .mu.m) and is directed parallel to the direction of an electric field, which is produced between the cathode and the anode electrodes of an electrochemical cell. The membrane material is designed to have physicochemical interaction with ions. Control of the extent of the interactions between the ions and the interior pore walls of the membrane and other materials, chemicals, or structures contained within the pores provides adjustability of the ionic conductivity of the membrane.

Gerald, II, Rex E; Ruscic, Katarina J; Sears, Devin N; Smith, Luis J; Klingler, Robert J; Rathke, Jerome W

2012-09-24T23:59:59.000Z

380

Membrane-based processes for sustainable power generation using water  

Science Journals Connector (OSTI)

... 18 GW of salinity-gradient power. Although 800 GW of power is currently obtained from hydroelectric processes globally, salinity-gradient energy remains a large and untapped resource. Capturing this energy ... not ions through the membranes to produce pressurized water that generates electricity using mechanical turbines. RED uses membranes for ion but not water transport, and the electrical ...

Bruce E. Logan; Menachem Elimelech

2012-08-15T23:59:59.000Z

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


381

Function of proteins  

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

Function of proteins Function of proteins Name: Collins Location: N/A Country: N/A Date: N/A Question: What is the function of proteins in your body? Replies: Proteins have many functions. They serve as enzymatic catalysts, are used as transport molecules (hemoglobin transports oxygen) and storage molecules (iron is stored in the liver as a complex with the protein ferritin); they are used in movement (proteins are the major component of muscles); they are needed for mechanical support (skin and bone contain collagen-a fibrous protein); they mediate cell responses (rhodopsin is a protein in the eye which is used for vision); antibody proteins are needed for immune protection; control of growth and cell differentiation uses proteins (hormones). These are just a few examples of the many, many functions of proteins.

382

A Mechanistic Study of Chemically Modified Inorganic Membranes for Gas and Liquid Separations  

SciTech Connect (OSTI)

This final report will summarize the progress made during the period August 1, 1993 - October 31, 2010 with support from DOE grant number DE-FG03-93ER14363. The objectives of the research have been to investigate the transport mechanisms in micro- and mesoporous, metal oxide membranes and to examine the relationship between the microstructure of the membrane, the membrane surface chemistry, and the separation performance of the membrane. Examples of the membrane materials under investigation are the microporous silica hollow fiber membrane manufactured by PPG Industries, chemically modified mesoporous oxide membranes, and polymer membranes containing microporous oxides (mixed matrix membranes). Analytical techniques such as NMR, FTIR and Raman spectroscopy, thermal analysis, and gas adsorption were used to investigate membrane microstructure and to probe the chemical interactions occurring at the gas-membrane interface.

Way, J Douglas

2011-01-21T23:59:59.000Z

383

Theoretical and experimental analysis of conductivity, ion diffusion and molecular transport during cell electroporation --Relation between short-lived and  

E-Print Network [OSTI]

electric field, which enables transport of molecules and ions across the cell membrane. Several and ions due to the hydrophobic nature of the lipid bilayer. Transport through the membrane occurs only for certain molecules and ions through membrane channels by means of diffusion or by active transport. However

Ljubljana, University of

384

An increasing number of synthetic compounds have been shown to facilitate ion and polar molecule transport across  

E-Print Network [OSTI]

transport of ions and polar molecules across biological membranes is essential for normal cell function synthetic transporters shown to be active in both model bilayers and cellular membranes. Mechanism of ion simulations of unassisted Na+ and Cl­ ion transport across a bilayer membrane. As the ion enters the outer

Smith, Bradley D.

385

Structural basis for membrane targeting by the MVB12-associated [beta]-prism domain of the human ESCRT-I MVB12 subunit  

SciTech Connect (OSTI)

MVB12-associated {beta}-prism (MABP) domains are predicted to occur in a diverse set of membrane-associated bacterial and eukaryotic proteins, but their existence, structure, and biochemical properties have not been characterized experimentally. Here, we find that the MABP domains of the MVB12A and B subunits of ESCRT-I are functional modules that bind in vitro to liposomes containing acidic lipids depending on negative charge density. The MABP domain is capable of autonomously localizing to subcellular puncta and to the plasma membrane. The 1.3-{angstrom} atomic resolution crystal structure of the MVB12B MABP domain reveals a {beta}-prism fold, a hydrophobic membrane-anchoring loop, and an electropositive phosphoinositide-binding patch. The basic patch is open, which explains how it senses negative charge density but lacks stereoselectivity. These observations show how ESCRT-I could act as a coincidence detector for acidic phospholipids and protein ligands, enabling it to function both in protein transport at endosomes and in cytokinesis and viral budding at the plasma membrane.

Boura, Evzen; Hurley, James H. (NIH)

2012-03-15T23:59:59.000Z

386

Poisson-Nernst-Planck systems for narrow tubular-like membrane and Bixiang Wang  

E-Print Network [OSTI]

membrane channels, transport of holes and electrons in semiconductors (see, e.g., [1, 2, 24, 4, 6, 7, 8, 17, 25]). In the context of ion flow through membrane channels, it is physicallyPoisson-Nernst-Planck systems for narrow tubular-like membrane channels Weishi Liu and Bixiang Wang

Liu, Weishi

387

Electric Field Modulation of the Membrane Potential in Solid-State Ion Channels  

E-Print Network [OSTI]

channel. KEYWORDS: Nanochannel, membrane potential, electrofluidic gating, ion transport, salinityElectric Field Modulation of the Membrane Potential in Solid-State Ion Channels Weihua Guan a rapid flow of ions across the cell membrane. Normal physiological functions, such as generating action

Reed, Mark

388

Rejection and fate of trace organic compounds (TrOCs) during membrane distillation  

E-Print Network [OSTI]

Rejection and fate of trace organic compounds (TrOCs) during membrane distillation Kaushalya COCs) Direct contact membrane distillation (DCMD) Volatility Fate and transport Hydrophobicity/hydrophilicity a b s t r a c t In this study, we examined the feasibility of membrane distillation (MD) for removing

389

Alkaline membrane fuel cells with in-situ cross-linked ionomers Yongjun Leng a  

E-Print Network [OSTI]

optimization is needed for the commercialization of alkaline membrane fuel cell (AMFC) technologiesAlkaline membrane fuel cells with in-situ cross-linked ionomers Yongjun Leng a , Lizhu Wang b membrane fuel cell (AMFC) in-situ cross-linking ionomer net water transport coefficient A B S T R A C

390

Glycosyl-phosphatidylinositol (GPI)-anchored membrane association of the porcine reproductive and respiratory syndrome virus GP4 glycoprotein and its co-localization with CD163 in lipid rafts  

SciTech Connect (OSTI)

The porcine reproductive and respiratory syndrome virus (PRRSV) glycoprotein 4 (GP4) resembles a typical type I membrane protein in its structure but lacks a hydrophilic tail at the C-terminus, suggesting that GP4 may be a lipid-anchored membrane protein. Using the human decay-accelerating factor (DAF; CD55), a known glycosyl-phosphatidylinositol (GPI) lipid-anchored protein, chimeric constructs were made to substitute the GPI-anchor domain of DAF with the putative lipid-anchor domain of GP4, and their membrane association and lipase cleavage were determined in cells. The DAF-GP4 fusion protein was transported to the plasma membrane and was cleaved by phosphatidylinositol-specific phospholipase C (PI-PLC), indicating that the C-terminal domain of GP4 functions as a GPI anchor. Mutational studies for residues adjacent to the GPI modification site and characterization of respective mutant viruses generated from infectious cDNA clones show that the ability of GP4 for membrane association corresponded to virus viability and growth characteristics. The residues T158 ({omega} - 2, where {omega} is the GPI moiety at E160), P159 ({omega} - 1), and M162 ({omega} + 2) of GP4 were determined to be important for virus replication, with M162 being of particular importance for virus infectivity. The complete removal of the peptide-anchor domain in GP4 resulted in a complete loss of virus infectivity. The depletion of cholesterol from the plasma membrane of cells reduced the virus production, suggesting a role of lipid rafts in PRRSV infection. Remarkably, GP4 was found to co-localize with CD163 in the lipid rafts on the plasma membrane. Since CD163 has been reported as a cellular receptor for PRRSV and GP4 has been shown to interact with this receptor, our data implicates an important role of lipid rafts during entry of the virus.

Du, Yijun [Department of Pathobiology, University of Illinois at Urbana-Champaign, 2001 South Lincoln Ave, Urbana, IL 61802 (United States) [Department of Pathobiology, University of Illinois at Urbana-Champaign, 2001 South Lincoln Ave, Urbana, IL 61802 (United States); Shandong Key Laboratory of Animal Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Jinan (China); Pattnaik, Asit K. [School of Veterinary Medicine and Biomedical Sciences and the Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE 68583-0900 (United States)] [School of Veterinary Medicine and Biomedical Sciences and the Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE 68583-0900 (United States); Song, Cheng [Department of Pathobiology, University of Illinois at Urbana-Champaign, 2001 South Lincoln Ave, Urbana, IL 61802 (United States)] [Department of Pathobiology, University of Illinois at Urbana-Champaign, 2001 South Lincoln Ave, Urbana, IL 61802 (United States); Yoo, Dongwan, E-mail: dyoo@illinois.edu [Department of Pathobiology, University of Illinois at Urbana-Champaign, 2001 South Lincoln Ave, Urbana, IL 61802 (United States)] [Department of Pathobiology, University of Illinois at Urbana-Champaign, 2001 South Lincoln Ave, Urbana, IL 61802 (United States); Li, Gang, E-mail: dyoo@illinois.edu [Department of Pathobiology, University of Illinois at Urbana-Champaign, 2001 South Lincoln Ave, Urbana, IL 61802 (United States) [Department of Pathobiology, University of Illinois at Urbana-Champaign, 2001 South Lincoln Ave, Urbana, IL 61802 (United States); Institute of Animal Science and Veterinary Medicine, Chinese Academy of Agricultural Sciences, Beijing (China)

2012-03-01T23:59:59.000Z

391

Chapter 11 - Nanofluidic Carbon Nanotube Membranes: Applications for Water Purification and Desalination  

Science Journals Connector (OSTI)

This chapter presents a brief overview of the basic physical processes that govern the structure and transport of water inside CNT pores, basic properties that make nanotube pore technologies attractive for water purification and desalination, the fabrication approaches for producing CNT membranes, and the experimental observations of water transport and ion exclusion properties in CNT membranes.

Olgica Bakajin; Aleksandr Noy; Francesco Fornasiero; Costas P. Grigoropoulos; Jason K. Holt; Jung Bin In; Sangil Kim; Hyung Gyu Park

2014-01-01T23:59:59.000Z

392

Water uptake, ionic conductivity and swelling properties of anion-exchange membrane  

E-Print Network [OSTI]

occurs with negative excess volume of mixing. Percolative nature of the ion transport has been is reduced at the cathode to produce OH? , which transports through the anion-exchange membrane (AEM membrane, AEM can conduct ions only in the presence of water. In addition, water is one of the reactants

393

Journal of Membrane Science 279 (2006) 608614 Direct measurement of nanofluxes and structural relaxations of  

E-Print Network [OSTI]

of the membrane are very important in explain- ing solvent swelling [8,9]. Besides water transport, the gas. For insufficiently hydrated Nafion® membranes, the proton transport is slow, and thus, the conversion efficiency. Originally, it was argued that the gas mainly permeates either through the hydrated ionic cluster region [10

394

Introduction Protein secretion is an essential process in prokaryotes and  

E-Print Network [OSTI]

Introduction Protein secretion is an essential process in prokaryotes and eukaryotes (Matlack et al., 1998). Protein synthesis takes place in the cytoplasm, therefore secretion requires one protein not understood. Protein translocation across biological membranes is dependent on temperature and membrane lipid

Cheng, Chi-Hing Christina

395

Composite zeolite membranes  

DOE Patents [OSTI]

A new class of composite zeolite membranes and synthesis techniques therefor has been invented. These membranes are essentially defect-free, and exhibit large levels of transmembrane flux and of chemical and isotopic selectivity.

Nenoff, Tina M. (Albuquerque, NM); Thoma, Steven G. (Albuquerque, NM); Ashley, Carol S. (Albuquerque, NM); Reed, Scott T. (Albuquerque, NM)

2002-01-01T23:59:59.000Z

396

Membrane Technology Workshop  

Broader source: Energy.gov [DOE]

At the Membrane Technology Workshop (held July 24, 2012, in Rosemont, IL), stakeholders from industry and academia explored the status of membrane research and development (R&D). Participants...

397

Membrane Technology Workshop  

Broader source: Energy.gov [DOE]

At the Membrane Technology Workshop (held July 24, 2012, in Rosemont, IL), stakeholders from industry and academia explored the status of membrane research and development (R&D). Participants ...

398

Hybrid adsorptive membrane reactor  

DOE Patents [OSTI]

A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

Tsotsis, Theodore T. (Huntington Beach, CA); Sahimi, Muhammad (Altadena, CA); Fayyaz-Najafi, Babak (Richmond, CA); Harale, Aadesh (Los Angeles, CA); Park, Byoung-Gi (Yeosu, KR); Liu, Paul K. T. (Lafayette Hill, PA)

2011-03-01T23:59:59.000Z

399

Supertubes and Superconducting Membranes  

SciTech Connect (OSTI)

We show the equivalence between configurations that arise from string theory of type IIA, called supertubes, and superconducting membranes at the bosonic level. We find equilibrium and oscillating configurations for a tubular membrane carrying a current along its axis.

Cordero, Ruben; Miguel-Pilar, Zelin [Departamento de Fisica, Escuela Superior de Fisica y Matematicas del IPN, Edificio 9, Unidad Profesional 'Adolfo Lopez Mateos', Zacatenco, 07738 Mexico D.F. (Mexico)

2007-02-09T23:59:59.000Z

400

Method for dialysis on microchips using thin porous polymer membrane  

DOE Patents [OSTI]

Laser-induced phase-separation polymerization of a porous acrylate polymer is used for in-situ fabrication of dialysis membranes inside glass microchannels. A shaped 355 nm laser beam is used to produce a porous polymer membrane with a thickness of about 15 .mu.m, which bonds to the glass microchannel and forms a semi-permeable membrane. Differential permeation through a membrane formed with pentaerythritol triacrylate was observed and quantified by comparing the response of the membrane to fluorescein and fluorescently tagging 200 nm latex microspheres. Differential permeation was observed and quantified by comparing the response to rhodamine 560 and lactalbumin protein in a membrane formed with SPE-methylene bisacrylamide. The porous membranes illustrate the capability for the present technique to integrate sample cleanup into chip-based analysis systems.

Singh, Anup K. (San Francisco, CA); Kirby, Brian J. (San Francisco, CA); Shepodd, Timothy J. (Livermore, CA)

2009-05-19T23:59:59.000Z

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


401

Dialysis on microchips using thin porous polymer membranes  

DOE Patents [OSTI]

Laser-induced phase-separation polymerization of a porous acrylate polymer is used for in-situ fabrication of dialysis membranes inside glass microchannels. A shaped 355 nm laser beam is used to produce a porous polymer membrane with a thickness of about 15 .mu.m, which bonds to the glass microchannel and form a semi-permeable membrane. Differential permeation through a membrane formed with pentaerythritol triacrylate was observed and quantified by comparing the response of the membrane to fluorescein and fluorescently tagging 200 nm latex microspheres. Differential permeation was observed and quantified by comparing the response to rhodamine 560 and lactalbumin protein in a membrane formed with SPE-methylene bisacrylamide. The porous membranes illustrate the capability for the present technique to integrate sample cleanup into chip-based analysis systems.

Singh, Anup K. (San Francisco, CA); Kirby, Brian J. (San Francisco, CA); Shepodd, Timothy J. (Livermore, CA)

2007-09-04T23:59:59.000Z

402

Membrane Separations Research  

E-Print Network [OSTI]

MEMBRANE SEPARATIONS RESEARCH James R. Fair Chemical Engineering Department The University of Texas at Austin Austin, TX 78712 ABSTRACT The use of membranes for separating gaseous and liquid mixtures has grown dramatically in the past 15... years. Applications have been dominated by light gas separations and water purification. During this pioneering period, equipment containing the membrane suIfaces has been developed to a point where failures are minimal and the membranes themselves...

Fair, J. R.

403

Membrane Technology Workshop  

Broader source: Energy.gov [DOE]

Presentation by Charles Page (Air Products & Chemicals, Inc.) for the Membrane Technology Workshop held July 24, 2012

404

Characterization of the Bacteriophage Lambda Holin and Its Membrane Lesion  

E-Print Network [OSTI]

optimized in this work, has been a valuable biochemical tool for analysis and reconstitution of the pathway to S105 hole formation in the cell membrane. iv Due to the difficulty associated with over-expression and purification of toxic membrane... ...................................................................................................... 34 Part I: Protection of Holin Thiols During Protein Purification....... 34 Results ................................................................................................ 35 Discussion...

Dewey, Jill Sayes

2011-10-21T23:59:59.000Z

405

Polyphosphazene semipermeable membranes  

DOE Patents [OSTI]

A semipermeable, inorganic membrane is disclosed; the membrane is prepared from a phosphazene polymer and, by the selective substitution of the constituent groups bound to the phosphorous in the polymer structure, the selective passage of fluid from a feedstream can be controlled. Resistance to high temperatures and harsh chemical environments is observed in the use of the phosphazene polymers as semipermeable membranes.

Allen, Charles A. (Idaho Falls, ID); McCaffrey, Robert R. (Idaho Falls, ID); Cummings, Daniel G. (Idaho Falls, ID); Grey, Alan E. (Idaho Falls, ID); Jessup, Janine S. (Darlington, ID); McAtee, Richard E. (Idaho Falls, ID)

1988-01-01T23:59:59.000Z

406

Challenging Proteins Principles and Methods  

E-Print Network [OSTI]

.............................................................................................................................................................12 Small-scale expression screening of histidine-tagged membrane proteins from E. coli lysates Gel Filtration Principles and Methods 18-1022-18 Recombinant Protein Purification Handbook Principles and Methods 18-1142-75 Protein Purification Handbook 18-1132-29 Hydrophobic Interaction and Reversed Phase

Jacobsen, Steve

407

Crystal Structure of the EmrE Multidrug Transporter with a Substrate  

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

the EmrE the EmrE Multidrug Transporter with a Substrate O. Pornillos, Y-J. Chen, A. P. Chen and G. Chang Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037 View of the EmrE homodimer. The N and C termini of the two subunits are colored. The bound substrate (TPP) is shown in green. The glutamine 14 which is implicated in the proton-depended drug translocation is shown in yellow. A major obstacle to effective treatment of bacterial infections is the emergence of drug-resistant strains. Multidrug resistance arises, in part, through the action of integral membrane proteins called multidrug transporters. Multidrug resistance transporters threaten to reverse the progress in treating infectious disease by extruding a wide range of drug

408

E-Print Network 3.0 - antibody-photosensitizer fusion protein...  

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

membrane stresses in fusion and fission Michael M. Kozlov1 , Harvey T. McMahon2... fusion or fission come from proteins andin most cases from membrane-bound proteins. In...

409

E-Print Network 3.0 - akar2-akap12 fusion protein Sample Search...  

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

membrane stresses in fusion and fission Michael M. Kozlov1 , Harvey T. McMahon2... fusion or fission come from proteins andin most cases from membrane-bound proteins. In...

410

E-Print Network 3.0 - antibody-gdnf fusion protein Sample Search...  

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

membrane stresses in fusion and fission Michael M. Kozlov1 , Harvey T. McMahon2... fusion or fission come from proteins andin most cases from membrane-bound proteins. In...

411

E-Print Network 3.0 - alkb proteins repair Sample Search Results  

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

Summary: BIO463 03-094 Structural Studies on the Integral Membrane Protein AlkB J. Shanklin BIO463 03... Bldg. 02-02 Crystallization and X-ray Analysis of Membrane Proteins D....

412

Charge Inversion, Water Splitting, and Vortex Suppression Due to DNA Sorption on Ion-Selective Membranes and Their Ion-Current  

E-Print Network [OSTI]

These membranes show a unique property of selective ion transport through the nanopores of IEMs embedded to saturate at a limiting current beyond a critical cross-membrane voltage drop as a result of the ion-transport-Selective Membranes and Their Ion-Current Signatures Zdenek Slouka, Satyajyoti Senapati, Yu Yan, and Hsueh-Chia Chang

Chang, Hsueh-Chia

413

DOE Science Showcase - Understanding Protein Membranes | OSTI...  

Office of Scientific and Technical Information (OSTI)

Information Bridge Energy Citations Database DOE R&D Accomplishments Database DOE R&D Project Summaries DOE Data Explorer Drug Research Documents from DOE Databases...

414

Lipidic phase membrane protein serial femtosecond crystallography  

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

crystallography Source: Nature Methods Year: 2012 Volume: 9 Pages: 263-265 ABSTRACT: X-ray free electron laser (X-FEL)-based serial femtosecond crystallography is an emerging...

415

Protein Targeting to the Bacterial Cytoplasmic Membrane  

Science Journals Connector (OSTI)

...Luirink J. High S. Wood H. Giner A. Tollervey D. Dobberstein...Mould R. M. Robinson C. A proton gradient is required for the...posttranslationally. . Ribes V. Romisch K. Giner A. Dobberstein B. Tollervey...Fersht A. R. Catalysis of amide proton exchange by the molecular chaperones...

Peter Fekkes; Arnold J. M. Driessen

1999-03-01T23:59:59.000Z

416

Enhanced membrane gas separations  

SciTech Connect (OSTI)

An improved membrane gas separation process is described comprising: (a) passing a feed gas stream to the non-permeate side of a membrane system adapted for the passage of purge gas on the permeate side thereof, and for the passage of the feed gas stream in a counter current flow pattern relative to the flow of purge gas on the permeate side thereof, said membrane system being capable of selectively permeating a fast permeating component from said feed gas, at a feed gas pressure at or above atmospheric pressure; (b) passing purge gas to the permeate side of the membrane system in counter current flow to the flow of said feed gas stream in order to facilitate carrying away of said fast permeating component from the surface of the membrane and maintaining the driving force for removal of the fast permeating component through the membrane from the feed gas stream, said permeate side of the membrane being maintained at a subatmospheric pressure within the range of from about 0.1 to about 5 psia by vacuum pump means; (c) recovering a product gas stream from the non-permeate side of the membrane; and (d) discharging purge gas and the fast permeating component that has permeated the membrane from the permeate side of the membrane, whereby the vacuum conditions maintained on the permeate side of the membrane by said vacuum pump means enhance the efficiency of the gas separation operation, thereby reducing the overall energy requirements thereof.

Prasad, R.

1993-07-13T23:59:59.000Z

417

Fuel Cell Technologies Office: High Temperature Membrane Working Group  

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

High Temperature Membrane Working Group High Temperature Membrane Working Group The High Temperature Membrane Working Group consists of government, industry, and university researchers interested in developing high temperature membranes for fuel cells. Description Technical Targets Meetings Contacts Description Polymer electrolyte membrane (PEM) fuel cells typically operate at temperatures no higher than 60°C-80°C due to structural limitations of the membrane. Operating PEM fuel cell stacks at higher temperatures (120°C for transportation and 150°C for stationary applications), however, would yield significant energy benefits. For example, heat rejection is easier at higher temperatures, which would allow use of smaller heat exchangers in fuel cell power systems. In addition, for reformate fuel cell systems, carbon monoxide (CO) tolerance of the stack is less problematic at higher temperatures, which would reduce the size requirements or possibly eliminate the need for some CO clean-up beds in the fuel processor.

418

Argonne CNM News: Thinnest Nanofiltration Membrane to Date  

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

Thinnest Nanofiltration Membrane to Date Thinnest Nanofiltration Membrane to Date Thinnest membrane to date Close-packed nanoparticle monolayers self-assembled from dodecanethiol-ligated gold nanocrystals. TEM image (left) and atomistic simulation of tryptophan transport through a pore. A recent collaboration between users at the University of Chicago and the University of Illinois at Chicago with the Center for Nanoscale Material's Electronic & Magnetic Materials & Devices Group has produced the thinnest nanofiltration membrane achieved thus far, at ~30 nm, made of just four layers of nanoparticles. A separation membrane is a key component in both nanofiltration and reverse osmosis filtration systems. Typically they are microns-thick polymer films. Reducing the thickness of the membrane reduces the pressure that needs to

419

Journal of Bioenergetics and Biomembranes, Vol. 36, No. 1, February 2004 ( C 2004) Extreme Secretion: Protein Translocation Across  

E-Print Network [OSTI]

Secretion: Protein Translocation Across the Archaeal Plasma Membrane Gabriela Ring1 and Jerry Eichler1- drophobic, lipid-based membranes. While numerous aspects of the protein translocation process have been well translocation process in vitro. KEY WORDS: Archaea; inverted membrane vesicles; protein secretion; protein

Eichler, Jerry

420

BASELINE MEMBRANE SELECTION AND CHARACTERIZATION FOR AN SDE  

SciTech Connect (OSTI)

Thermochemical processes are being developed to provide global-scale quantities of hydrogen. A variant on sulfur-based thermochemical cycles is the Hybrid Sulfur (HyS) Process which uses a sulfur dioxide depolarized electrolyzer (SDE) to produce the hydrogen. In FY05 and FY06, testing at the Savannah River National Laboratory (SRNL) explored a low temperature fuel cell design concept for the SDE. The advantages of this design concept include high electrochemical efficiency and small footprint that are crucial for successful implementation on a commercial scale. A key component of the SDE is the ion conductive membrane through which protons produced at anode migrate to the cathode and react to produce hydrogen. An ideal membrane for the SDE should have both low ionic resistivity and low sulfur dioxide transport. These features allow the electrolyzer to perform at high currents with low potentials, along with preventing contamination of both the hydrogen output and poisoning of the catalysts involved. Another key component is the electrocatalyst material used for the anode and cathode. Good electrocatalysts should be chemically stable and have a low overpotential for the desired electrochemical reactions. This report summarizes results from activities to evaluate commercial and experimental membranes for the SDE. Several different types of commercially-available membranes were analyzed for sulfur dioxide transport as a function of acid strength including perfluorinated sulfonic acid (PFSA), sulfonated poly-etherketone-ketone, and poly-benzimidazole (PBI) membranes. Experimental membranes from the sulfonated diels-alder polyphenylenes (SDAPP) and modified Nafion{reg_sign} 117 were evaluated for SO{sub 2} transport as well. These membranes exhibited reduced transport coefficient for SO{sub 2} transport without the loss in ionic conductivity. The use of Nafion{reg_sign} with EW 1100 is recommended for the present SDE testing due to the limited data regarding chemical and mechanical stability of experimental membranes. Development of new composite membranes by incorporating metal particles or by forming multilayers between PFSA membranes and hydrocarbon membranes will provide methods that will meet the SDE targets (SO{sub 2} transport reduction by a factor of 100) while decreasing catalyst layer delamination and membrane resistivity.

Colon-Mercado, H; David Hobbs, D

2007-04-03T23:59:59.000Z

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


421

JournalofCellScience The Drosophila RZZ complex roles in membrane  

E-Print Network [OSTI]

involved in Drosophila membrane trafficking. Here we show that Zw10 is enriched at both the Golgi stacks, 2008). Although membrane addition is crucial for cytokinesis, the inventory of proteins involved melanogaster is a highly suitable system for the identification and functional characterization of membrane

Boyer, Edmond

422

Characterization of vanadate-dependent NADH oxidation stimulated by Saccharomyces cerevisiae plasma membranes.  

Science Journals Connector (OSTI)

...various concentrations of plasma membrane protein (17...of vana- date only. Plasma membrane-stimulated...Spectra were obtained at 71 MHz on a JEOL FX 270 NMR Fourier...deadtime. Sweep widths of 50 kHz were used. A line-broadening...glycerol gradient-purified plasma membrane-enriched fractionsa...

L A Minasi; G R Willsky

1991-01-01T23:59:59.000Z

423

Genome-Scale Identification of Membrane-Associated Human mRNAs  

E-Print Network [OSTI]

-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America, 5 of medicine. Plasma membrane proteins and secreted signaling proteins are candidate targets for monoclonal

Botstein, David

424

Molecular chaperone Hsp110 rescues a vesicle transport defect produced by an ALS-associated mutant SOD1 protein in squid axoplasm  

Science Journals Connector (OSTI)

...11 ): 1396 1403 . 34 Morfini GA ( 2009 ) Axonal transport defects in neurodegenerative diseases . J Neurosci 29 ( 41 ): 12776 12786 . 35 Munoz L ( 2007 ) A novel p38 alpha MAPK inhibitor suppresses brain proinflammatory cytokine up-regulation and...

Yuyu Song; Maria Nagy; Weiming Ni; Navneet K. Tyagi; Wayne A. Fenton; Francesc Lpez-Girldez; John D. Overton; Arthur L. Horwich; Scott T. Brady

2013-01-01T23:59:59.000Z

425

Glucose Transporters in the Transepithelial Transport of Glucose  

Science Journals Connector (OSTI)

......galactose, and fructose formed by the hydrolysis of dietary car- bohydrates.181 In the liver, GLUT2 at the sinusoidal membrane...transport activity. These results show that SGLTl is a key defective molecule in GGM and that SGLTl is crucial for the absorption......

Kuniaki Takata

1996-08-01T23:59:59.000Z

426

E-Print Network 3.0 - affecting protein folding Sample Search...  

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

protein folding Search Powered by Explorit Topic List Advanced Search Sample search results for: affecting protein folding Page: << < 1 2 3 4 5 > >> 1 Current status of membrane...

427

Substituted polyacetylene separation membrane  

DOE Patents [OSTI]

A separation membrane is described which is useful for gas separation, particularly separation of C{sub 2+} hydrocarbons from natural gas. The invention encompasses the membrane itself, methods of making it and processes for using it. The membrane comprises a polymer having repeating units of a hydrocarbon-based, disubstituted polyacetylene, having the general formula shown in the accompanying diagram, wherein R{sub 1} is chosen from the group consisting of C{sub 1}-C{sub 4} alkyl and phenyl, and wherein R{sub 2} is chosen from the group consisting of hydrogen and phenyl. In the most preferred embodiment, the membrane comprises poly(4-methyl-2-pentyne) [PMP]. The membrane exhibits good chemical resistance and has super-glassy properties with regard to separating certain large, condensable permeant species from smaller, less-condensable permeant species. The membranes may also be useful in other fluid separations. 4 figs.

Pinnau, I.; Morisato, Atsushi

1998-01-13T23:59:59.000Z

428

Substituted polyacetylene separation membrane  

DOE Patents [OSTI]

A separation membrane useful for gas separation, particularly separation of C.sub.2+ hydrocarbons from natural gas. The invention encompasses the membrane itself, methods of making it and processes for using it. The membrane comprises a polymer having repeating units of a hydrocarbon-based, disubstituted polyacetylene, having the general formula: ##STR1## wherein R.sub.1 is chosen from the group consisting of C.sub.1 -C.sub.4 alkyl and phenyl, and wherein R.sub.2 is chosen from the group consisting of hydrogen and phenyl. In the most preferred embodiment, the membrane comprises poly(4-methyl-2-pentyne) PMP!. The membrane exhibits good chemical resistance and has super-glassy properties with regard to separating certain large, condensable permeant species from smaller, less-condensable permeant species. The membranes may also be useful in other fluid separations.

Pinnau, Ingo (Palo Alto, CA); Morisato, Atsushi (Tokyo, JP)

1998-01-13T23:59:59.000Z

429

EVALUATION OF PROTON-CONDUCTING MEMBRANES FOR USE IN A SULFUR-DIOXIDE DEPOLARIZED ELECTROLYZER  

SciTech Connect (OSTI)

The chemical stability, sulfur dioxide transport, ionic conductivity, and electrolyzer performance have been measured for several commercially available and experimental proton exchange membranes (PEMs) for use in a sulfur dioxide depolarized electrolyzer (SDE). The SDE's function is to produce hydrogen by using the Hybrid Sulfur (HyS) Process, a sulfur based electrochemical/thermochemical hybrid cycle. Membrane stability was evaluated using a screening process where each candidate PEM was heated at 80 C in 60 wt. % H{sub 2}SO{sub 4} for 24 hours. Following acid exposure, chemical stability for each membrane was evaluated by FTIR using the ATR sampling technique. Membrane SO{sub 2} transport was evaluated using a two-chamber permeation cell. SO{sub 2} was introduced into one chamber whereupon SO{sub 2} transported across the membrane into the other chamber and oxidized to H{sub 2}SO{sub 4} at an anode positioned immediately adjacent to the membrane. The resulting current was used to determine the SO{sub 2} flux and SO{sub 2} transport. Additionally, membrane electrode assemblies (MEAs) were prepared from candidate membranes to evaluate ionic conductivity and selectivity (ionic conductivity vs. SO{sub 2} transport) which can serve as a tool for selecting membranes. MEAs were also performance tested in a HyS electrolyzer measuring current density versus a constant cell voltage (1V, 80 C in SO{sub 2} saturated 30 wt% H2SO{sub 4}). Finally, candidate membranes were evaluated considering all measured parameters including SO{sub 2} flux, SO{sub 2} transport, ionic conductivity, HyS electrolyzer performance, and membrane stability. Candidate membranes included both PFSA and non-PFSA polymers and polymer blends of which the non-PFSA polymers, BPVE-6F and PBI, showed the best selectivity.

Hobbs, D.; Elvington, M.; Colon-Mercado, H.

2009-11-11T23:59:59.000Z

430

Anion exchange membrane  

DOE Patents [OSTI]

An anion exchange membrane and fuel cell incorporating the anion exchange membrane are detailed in which proazaphosphatrane and azaphosphatrane cations are covalently bonded to a sulfonated fluoropolymer support along with anionic counterions. A positive charge is dispersed in the aforementioned cations which are buried in the support to reduce the cation-anion interactions and increase the mobility of hydroxide ions, for example, across the membrane. The anion exchange membrane has the ability to operate at high temperatures and in highly alkaline environments with high conductivity and low resistance.

Verkade, John G; Wadhwa, Kuldeep; Kong, Xueqian; Schmidt-Rohr, Klaus

2013-05-07T23:59:59.000Z

431

The role of transmembrane domains in membrane fusion D. Langoscha, *, M. Hofmanna  

E-Print Network [OSTI]

. Biological membrane fusion is driven by different types of molecular fusion machines. Most of these proteins of eukaryotic cells by enveloped viruses. Although both types of fusion proteins are evolutionarily quiteReview The role of transmembrane domains in membrane fusion D. Langoscha, *, M. Hofmanna and C

Ungermann, Christian

432

Transportation Services  

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

Transportation Services Transporting nuclear materials within the United States and throughout the world is a complicated and sometimes highly controversial effort requiring...

433

Local Transportation  

E-Print Network [OSTI]

Local Transportation. Transportation from the Airport to Hotel. There are two types of taxi companies that operate at the airport: special and regular taxis (

434

E-Print Network 3.0 - anion transporter sat1 Sample Search Results  

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

(ClC) family... in the complex network of membrane transport and solute fluxes. We used a reverse genetics approach with T Source: Groningen, Rijksuniversiteit - Centre for...

435

E-Print Network 3.0 - anion transporters oat1 Sample Search Results  

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

(ClC) family... in the complex network of membrane transport and solute fluxes. We used a reverse genetics approach with T Source: Groningen, Rijksuniversiteit - Centre for...

436

Does ionophore A23187 mediate Na transport in the absence of divalent cations?  

Science Journals Connector (OSTI)

... L. & Beaug, L. in Transport Across Biological Membranes (eds Giebisch, G., Tosteson, D. C. & Ussing, H. H.) vol. 2 (Springer, in ...

PETER FLATMAN; VIRGILIO L. LEW

1977-12-01T23:59:59.000Z

437

Effective zero-thickness model for a conductive membrane driven by an electric field Falko Ziebert,1  

E-Print Network [OSTI]

membrane models is that they do not describe electrostatic effects associated with ion transport in details cells. A membrane can be driven out of equilibrium in many ways, for instance by ion concentration. The generation of ion con- centration gradients by internal means is controlled in bio- logical cells by membrane

Bazant, Martin Z.

438

Integrated Ceramic Membrane System for Hydrogen Production  

SciTech Connect (OSTI)

Phase I was a technoeconomic feasibility study that defined the process scheme for the integrated ceramic membrane system for hydrogen production and determined the plan for Phase II. The hydrogen production system is comprised of an oxygen transport membrane (OTM) and a hydrogen transport membrane (HTM). Two process options were evaluated: 1) Integrated OTM-HTM reactor in this configuration, the HTM was a ceramic proton conductor operating at temperatures up to 900C, and 2) Sequential OTM and HTM reactors in this configuration, the HTM was assumed to be a Pd alloy operating at less than 600C. The analysis suggested that there are no technical issues related to either system that cannot be managed. The process with the sequential reactors was found to be more efficient, less expensive, and more likely to be commercialized in a shorter time than the single reactor. Therefore, Phase II focused on the sequential reactor system, specifically, the second stage, or the HTM portion. Work on the OTM portion was conducted in a separate program. Phase IIA began in February 2003. Candidate substrate materials and alloys were identified and porous ceramic tubes were produced and coated with Pd. Much effort was made to develop porous substrates with reasonable pore sizes suitable for Pd alloy coating. The second generation of tubes showed some improvement in pore size control, but this was not enough to get a viable membrane. Further improvements were made to the porous ceramic tube manufacturing process. When a support tube was successfully coated, the membrane was tested to determine the hydrogen flux. The results from all these tests were used to update the technoeconomic analysis from Phase I to confirm that the sequential membrane reactor system can potentially be a low-cost hydrogen supply option when using an existing membrane on a larger scale. Phase IIB began in October 2004 and focused on demonstrating an integrated HTM/water gas shift (WGS) reactor to increase CO conversion and produce more hydrogen than a standard water gas shift reactor would. Substantial improvements in substrate and membrane performance were achieved in another DOE project (DE-FC26-07NT43054). These improved membranes were used for testing in a water gas shift environment in this program. The amount of net H2 generated (defined as the difference of hydrogen produced and fed) was greater than would be produced at equilibrium using conventional water gas shift reactors up to 75 psig because of the shift in equilibrium caused by continuous hydrogen removal. However, methanation happened at higher pressures, 100 and 125 psig, and resulted in less net H2 generated than would be expected by equilibrium conversion alone. An effort to avoid methanation by testing in more oxidizing conditions (by increasing CO2/CO ratio in a feed gas) was successful and net H2 generated was higher (40-60%) than a conventional reactor at equilibrium at all pressures tested (up to 125 psig). A model was developed to predict reactor performance in both cases with and without methanation. The required membrane area depends on conditions, but the required membrane area is about 10 ft2 to produce about 2000 scfh of hydrogen. The maximum amount of hydrogen that can be produced in a membrane reactor decreased significantly due to methanation from about 2600 scfh to about 2400 scfh. Therefore, it is critical to eliminate methanation to fully benefit from the use of a membrane in the reaction. Other modeling work showed that operating a membrane reactor at higher temperature provides an opportunity to make the reactor smaller and potentially provides a significant capital cost savings compared to a shift reactor/PSA combination.

Schwartz, Joseph; Lim, Hankwon; Drnevich, Raymond

2010-08-05T23:59:59.000Z

439

Chamber transport  

SciTech Connect (OSTI)

Heavy ion beam transport through the containment chamber plays a crucial role in all heavy ion fusion (HIF) scenarios. Here, several parameters are used to characterize the operating space for HIF beams; transport modes are assessed in relation to evolving target/accelerator requirements; results of recent relevant experiments and simulations of HIF transport are summarized; and relevant instabilities are reviewed. All transport options still exist, including (1) vacuum ballistic transport, (2) neutralized ballistic transport, and (3) channel-like transport. Presently, the European HIF program favors vacuum ballistic transport, while the US HIF program favors neutralized ballistic transport with channel-like transport as an alternate approach. Further transport research is needed to clearly guide selection of the most attractive, integrated HIF system.

OLSON,CRAIG L.

2000-05-17T23:59:59.000Z

440

Biominetic Membrane for Co2 Capture from Flue Gas  

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

Biomimetic Membrane for CO Biomimetic Membrane for CO 2 Capture from Flue Gas Background Carbon Capture and Sequestration (CCS) is a three-step process including capture, pipeline transport, and geologic storage of which the capture of carbon dioxide (CO 2 ) is the most costly and technically challenging. Current available methods impose significant energy burdens that severely impact their overall effectiveness as a significant deployment option. Of the available capture technologies for post

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


441

DOE Hydrogen Analysis Repository: Cost Analysis of Proton Exchange Membrane  

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

Cost Analysis of Proton Exchange Membrane Fuel Cell Systems for Cost Analysis of Proton Exchange Membrane Fuel Cell Systems for Transportation Project Summary Full Title: Cost Analysis of Proton Exchange Membrane (PEM) Fuel Cell Systems for Transportation Project ID: 196 Principal Investigator: Eric Carlson Keywords: Fuel cells, fuel cell vehicles (FCV), transportation, costs Purpose Assess the cost of an 80 kW direct hydrogen fuel cell system relative to the DOE 2005 target of $125/kW. The system includes the fuel cell stack and balance-of-plant (BOP) components for water, thermal, and fuel management, but not hydrogen storage. Performer Principal Investigator: Eric Carlson Organization: TIAX, LLC Address: 15 Acorn Park Cambridge, MA 02140-2328 Telephone: 617-498-5903 Email: carlson.e@tiaxllc.com Additional Performers: P. Kopf, TIAX, LLC; J. Sinha, TIAX, LLC; S. Sriramulu, TIAX, LLC

442

Novel, Ceramic Membrane System For Hydrogen Separation  

SciTech Connect (OSTI)

Separation of hydrogen from coal gas represents one of the most promising ways to produce alternative sources of fuel. Ceramatec, teamed with CoorsTek and Sandia National Laboratories has developed materials technology for a pressure driven, high temperature proton-electron mixed conducting membrane system to remove hydrogen from the syngas. This system separates high purity hydrogen and isolates high pressure CO{sub 2} as the retentate, which is amenable to low cost capture and transport to storage sites. The team demonstrated a highly efficient, pressure-driven hydrogen separation membrane to generate high purity hydrogen from syngas using a novel ceramic-ceramic composite membrane. Recognizing the benefits and limitations of present membrane systems, the all-ceramic system has been developed to address the key technical challenges related to materials performance under actual operating conditions, while retaining the advantages of thermal and process compatibility offered by the ceramic membranes. The feasibility of the concept has already been demonstrated at Ceramatec. This project developed advanced materials composition for potential integration with water gas shift rectors to maximize the hydrogenproduction.

Elangovan, S.

2012-12-31T23:59:59.000Z

443

Influence of Ibuprofen on Phospholipid Membranes  

E-Print Network [OSTI]

Basic understanding of biological membranes is of paramount importance as these membranes comprise the very building blocks of life itself. Cells depend in their function on a range of properties of the membrane, which are important for the stability and function of the cell, information and nutrient transport, waste disposal and finally the admission of drugs into the cell and also the deflection of bacteria and viruses. We have investigated the influence of ibuprofen on the structure and dynamics of L-alpha-phosphatidylcholine (SoyPC) membranes by means of grazing incidence small-angle neutron scattering (GISANS), neutron reflectometry and grazing incidence neutron spin echo spectroscopy (GINSES). From the results of these experiments we were able to determine that ibuprofen induces a two-step structuring behavior in the SoyPC films, where the structure evolves from the purely lamellar phase for pure SoyPC over a superposition of two hexagonal phases to a purely hexago- nal phase at high concentrations. Additionally, introduction of ibuprofen stiffens the membranes. This behavior may be instrumental in explaining the toxic behavior of ibuprofen in long-term application.

Sebastian Jaksch; Frederik Lipfert; Alexandros Koutsioubas; Stefan Mattauch; Olaf Holderer; Oxana Ivanova; Henrich Frielinghaus; Samira Hertrich; Stefan F. Fischer; Bert Nickel

2014-06-13T23:59:59.000Z

444

J. Membrane Biol. 4,179-192 (1971) 9 by Springer-Verlag New York Inc. 1971  

E-Print Network [OSTI]

antibiotics increase the ion permeability of biological membranes have been carried out on artificial model the possibility that they may serve as model systems for active transport across biological membranes. Moore and Pressman (1964) discovered the influence of valinomycin on the ion transport across the mitochondrial

Junge, Wolfgang

445

Membrane module assembly  

DOE Patents [OSTI]

A membrane module assembly is described which is adapted to provide a flow path for the incoming feed stream that forces it into prolonged heat-exchanging contact with a heating or cooling mechanism. Membrane separation processes employing the module assembly are also disclosed. The assembly is particularly useful for gas separation or pervaporation. 2 figures.

Kaschemekat, J.

1994-03-15T23:59:59.000Z

446

Current status and development of membranes for CO2/CH4 separation: A review  

Science Journals Connector (OSTI)

Carbon dioxide (CO2) is a greenhouse gas found primarily as a main combustion product of fossil fuel as well as a component in natural gas, biogas and landfill gas. The interest to remove CO2 from those gas streams to obtain fuel with enhanced energy content and prevent corrosion problems in the gas transportation system, in addition to CO2 implications to the climate change, has driven the development of CO2 separation process technology. One type of technology which has experienced substantial growth, breakthroughs and advances during past decades is membrane-based technology. The attractive features offered by this technology include high energy efficiency, simplicity in design and construction of membrane modules and environmental compatibility. The objective of this review is to overview the different types of membranes available for use including their working principles, current status and development which form the primary determinants of separation performance and efficiency. The emphasis is toward CO2/CH4 separation, considering its substantial and direct relevance to the gas industry. To this end, discussion is made to cover polymeric gas permeation membranes; CO2-selective facilitated transport membranes, hollow fiber gasliquid membrane contactors, inorganic membranes and mixed matrix membranes. The market for CO2 separation is currently dominated by polymeric membranes due to their relatively low manufacturing cost and processing ability into flat sheet and hollow fiber configurations as well as well-documented research studies. While there have been immensely successful membrane preparation and development techniques with consequential remarkable performance for each type of membrane. Each type of membrane brings associated advantages and drawbacks related to the characteristic transport mechanism for specific application conditions. Inorganic membranes, for example, are very suitable for high temperature CO2 separation in excess of 400C while all other membranes can be applied at lower temperatures. The recent emergence of mixed matrix membranes has allowed the innovative approach to combine the advantages offered by inorganic and polymeric materials.

Yuan Zhang; Jaka Sunarso; Shaomin Liu; Rong Wang

2013-01-01T23:59:59.000Z

447

Biomimetric Membrane for CO2 Capture from Flue Gas  

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

Biomimetic memBrane for co Biomimetic memBrane for co 2 capture from flue Gas Background Carbon Capture and Sequestration (CCS) is a three-step process including capture, pipeline transport and geologic storage of which the capture of carbon dioxide (CO 2 ) is the most costly and technically challenging. Current available methods impose significant energy burdens that severely impact their overall effectiveness as a significant deployment option. Of the available capture technologies for post combustion applications - absorption, adsorption, reaction and membranes chemically facilitated absorption promises to be the most cost-effective membrane solution for post combustion application. The Carbozyme technology extracts CO 2 from low concentration, low pressure sources by means of chemical facilitation of a polymer membrane. The chemical

448

Computational and experimental study of nanoporous membranes for water desalination and decontamination.  

SciTech Connect (OSTI)

Fundamentals of ion transport in nanopores were studied through a joint experimental and computational effort. The study evaluated both nanoporous polymer membranes and track-etched nanoporous polycarbonate membranes. The track-etched membranes provide a geometrically well characterized platform, while the polymer membranes are more closely related to ion exchange systems currently deployed in RO and ED applications. The experimental effort explored transport properties of the different membrane materials. Poly(aniline) membranes showed that flux could be controlled by templating with molecules of defined size. Track-etched polycarbonate membranes were modified using oxygen plasma treatments, UV-ozone exposure, and UV-ozone with thermal grafting, providing an avenue to functionalized membranes, increased wettability, and improved surface characteristic lifetimes. The modeling effort resulted in a novel multiphysics multiscale simulation model for field-driven transport in nanopores. This model was applied to a parametric study of the effects of pore charge and field strength on ion transport and charge exclusion in a nanopore representative of a track-etched polycarbonate membrane. The goal of this research was to uncover the factors that control the flux of ions through a nanoporous material and to develop tools and capabilities for further studies. Continuation studies will build toward more specific applications, such as polymers with attached sulfonate groups, and complex modeling methods and geometries.

Hickner, Michael A. (Penn State University, University Park, PA); Chinn, Douglas Alan (Sandia National Laboratories, Albuquerque, NM); Adalsteinsson, Helgi; Long, Kevin R. (Texas Tech University, Lubbock, TX); Kent, Michael Stuart (Sandia National Laboratories, Albuquerque, NM); Debusschere, Bert J.; Zendejas, Frank J.; Tran, Huu M.; Najm, Habib N.; Simmons, Blake Alexander

2008-11-01T23:59:59.000Z

449

Identification of the membrane association of BV/ODV E26 and the domains in BV/ODV E26 responsible for nuclear trafficking to intranuclear microvesicles  

E-Print Network [OSTI]

part of the 26 kDa population is a membrane bound form interacting with an integral membrane protein in the ER and likely functions as an INM sorting factor. The 26 kDa membrane bond form is also found in the inner nuclear membrane, intra-nuclear...

Burks, Jared K.

2007-04-25T23:59:59.000Z

450

Novel membrane technology for green ethylene production.  

SciTech Connect (OSTI)

Ethylene is currently produced by pyrolysis of ethane in the presence of steam. This reaction requires substantial energy input, and the equilibrium conversion is thermodynamically limited. The reaction also produces significant amounts of greenhouse gases (CO and CO{sub 2}) because of the direct contact between carbon and steam. Argonne has demonstrated a new way to make ethylene via ethane dehydrogenation using a dense hydrogen transport membrane (HTM) to drive the unfavorable equilibrium conversion. Preliminary experiments show that the new approach can produce ethylene yields well above existing pyrolysis technology and also significantly above the thermodynamic equilibrium limit, while completely eliminating the production of greenhouse gases. With Argonne's approach, a disk-type dense ceramic/metal composite (cermet) membrane is used to produce ethylene by dehydrogenation of ethane at 850 C. The gas-transport membrane reactor combines a reversible chemical reaction with selective separation of one product species and leads to increased reactant conversion to the desired product. In an experiment ethane was passed over one side of the HTM membrane and air over the other side. The hydrogen produced by the dehydrogenation of ethane was removed and transported through the HTM to the air side. The air provided the driving force required for the transport of hydrogen through the HTM. The reaction between transported hydrogen and oxygen in air can provide the energy needed for the dehydrogenation reaction. At 850 C and 1-atm pressure, equilibrium conversion of ethane normally limits the ethylene yield to 64%, but Argonne has shown that an ethylene yield of 69% with a selectivity of 88% can be obtained under the same conditions. Coking was not a problem in runs extending over several weeks. Further improved HTM materials will lower the temperature required for high conversion at a reasonable residence time, while the lower temperature will suppress unwanted side reactions and prolong membrane life. With the Argonne approach, oxygen does not contact the ethane/ethylene stream, so oxidation products are not formed. Consequently, higher selectivity to ethylene and fewer by-products can be achieved. Some benefits are: (1) Simplifies overall product purification and processing schemes; (2) Results in greater energy efficiency; (3) Completely eliminates greenhouse gases from the reactor section; and (4) Lowers the cost of the 'back end' purification train, which accounts for about 70% of the capital cost of a conventional ethylene production unit.

Balachandran, U.; Lee, T. H.; Dorris, S. E.; Udovich, C. A.; Scouten, C. G.; Marshall, C. L. (Energy Systems); ( CSE)

2008-01-01T23:59:59.000Z

451

Original article Flat ceramic membranes  

E-Print Network [OSTI]

membranes. The orig- inal intellectual concept is protected by two international patents. Strategically of investment and functioning costs while keeping the interest of ceramics. ceramic membrane / plate / tubular

Paris-Sud XI, Université de

452

High Temperature Membrane Working Group  

Broader source: Energy.gov [DOE]

The High Temperature Membrane Working Group consists of government, industry, and university researchers interested in developing high temperature membranes for fuel cells.

453

Ordered ceramic membranes  

SciTech Connect (OSTI)

Ceramic membranes have been formed from colloidal sols coated on porous clay supports. These supported membranes have been characterized in terms of their permeabilities and permselectivities to various aqueous test solutions. The thermal stabilities and pore structures of these membranes have been characterized by preparing unsupported membranes of the correpsonding material and performing N{sub 2} adsorption-desorption and X-ray diffraction studies on these membranes. To date, membranes have been prepared from a variety of oxides, including TiO{sub 2}, SiO{sub 2}, ZrO{sub 2}, and Al{sub 2}O{sub 3}, as well as Zr-, Fe-, and Nb-doped TiO{sub 2}. In many of these membranes pore diameters are less than 2 nm, while in others the pore diameters are between 3 and 5 nm. Procedures for fabricating porous clay supports with reproducible permeabilities for pure water are also discussed. 30 refs., 59 figs., 22 tabs.

Anderson, M.A.; Hill, C.G. Jr.; Zeltner, W.A.

1991-10-01T23:59:59.000Z

454

Catalytic nanoporous membranes  

DOE Patents [OSTI]

A nanoporous catalytic membrane which displays several unique features Including pores which can go through the entire thickness of the membrane. The membrane has a higher catalytic and product selectivity than conventional catalysts. Anodic aluminum oxide (AAO) membranes serve as the catalyst substrate. This substrate is then subjected to Atomic Layer Deposition (ALD), which allows the controlled narrowing of the pores from 40 nm to 10 nm in the substrate by deposition of a preparatory material. Subsequent deposition of a catalytic layer on the inner surfaces of the pores reduces pore sizes to less than 10 nm and allows for a higher degree of reaction selectivity. The small pore sizes allow control over which molecules enter the pores, and the flow-through feature can allow for partial oxidation of reactant species as opposed to complete oxidation. A nanoporous separation membrane, produced by ALD is also provided for use in gaseous and liquid separations. The membrane has a high flow rate of material with 100% selectivity. Also provided is a method for producing a catalytic membrane having flow-through pores and discreet catalytic clusters adhering to the inside surfaces of the pores.

Pellin, Michael J; Hryn, John N; Elam, Jeffrey W

2013-08-27T23:59:59.000Z

455

CENTRIFUGAL MEMBRANE FILTRATION  

SciTech Connect (OSTI)

The overall project consists of several integrated research phases related to the applicability, continued development, demonstration, and commercialization of the SpinTek centrifugal membrane filtration process. Work performed during this reporting period consisted of Phase 2 evaluation of the SpinTek centrifugal membrane filtration technology and Phase 3, Technology Partnering. During Phase 1 testing conducted at the EERC using the SpinTek ST-IIL unit operating on a surrogate tank waste, a solids cake developed on the membrane surface. The solids cake was observed where linear membrane velocities were less than 17.5 ft/s and reduced the unobstructed membrane surface area up to 25%, reducing overall filtration performance. The primary goal of the Phase 2 research effort was to enhance filtration performance through the development and testing of alternative turbulence promoter designs. The turbulence promoters were designed to generate a shear force across the entire membrane surface sufficient to maintain a self-cleaning membrane capability and improve filtration efficiency and long-term performance. Specific Phase 2 research activities included the following: System modifications to accommodate an 11-in.-diameter, two-disk rotating membrane assembly; Development and fabrication of alternative turbulence promoter designs; Testing and evaluation of the existing and alternative turbulence promoters under selected operating conditions using a statistically designed test matrix; and Data reduction and analysis; The objective of Phase 3 research was to demonstrate the effectiveness of SpinTek's centrifugal membrane filtration as a pretreatment to remove suspended solids from a liquid waste upstream of 3M's WWL cartridge technology for the selective removal of technetium (Tc).

Daniel J. Stepan; Bradley G. Stevens; Melanie D. Hetland

1999-10-01T23:59:59.000Z

456

Composite metal membrane  

DOE Patents [OSTI]

A composite metal membrane including a first metal layer of Group IVB met or Group VB metals, the first metal layer sandwiched between two layers of an oriented metal of palladium, platinum or alloys thereof is provided together with a process for the recovery of hydrogen from a gaseous mixture including contacting a hydrogen-containing gaseous mixture with a first side of a nonporous composite metal membrane including a first metal of Group IVB metals or Group VB metals, the first metal layer sandwiched between two layers of an oriented metal of palladium, platinum or alloys thereof, and, separating hydrogen from a second side of the nonporous composite metal membrane.

Peachey, Nathaniel M. (Espanola, NM); Dye, Robert C. (Los Alamos, NM); Snow, Ronny C. (Los Alamos, NM); Birdsell, Stephan A. (Los Alamos, NM)

1998-01-01T23:59:59.000Z

457

Composite metal membrane  

DOE Patents [OSTI]

A composite metal membrane including a first metal layer of Group IVB met or Group VB metals, the first metal layer sandwiched between two layers of an oriented metal of palladium, platinum or alloys thereof is provided together with a process for the recovery of hydrogen from a gaseous mixture including contacting a hydrogen-containing gaseous mixture with a first side of a nonporous composite metal membrane including a first metal of Group IVB metals or Group VB metals, the first metal layer sandwiched between two layers of an oriented metal of palladium, platinum or alloys thereof, and, separating hydrogen from a second side of the nonporous composite metal membrane.

Peachey, N.M.; Dye, R.C.; Snow, R.C.; Birdsell, S.A.

1998-04-14T23:59:59.000Z

458

Sequestration and Transport of Lignin Monomeric Precursors  

SciTech Connect (OSTI)

Lignin is the second most abundant terrestrial biopolymer after cellulose. It is essential for the viability of vascular plants. Lignin precursors, the monolignols, are synthesized within the cytosol of the cell. Thereafter, these monomeric precursors are exported into the cell wall, where they are polymerized and integrated into the wall matrix. Accordingly, transport of monolignols across cell membranes is a critical step affecting deposition of lignin in the secondarily thickened cell wall. While the biosynthesis of monolignols is relatively well understood, our knowledge of sequestration and transport of these monomers is sketchy. In this article, we review different hypotheses on monolignol transport and summarize the recent progresses toward the understanding of the molecular mechanisms underlying monolignol sequestration and transport across membranes. Deciphering molecular mechanisms for lignin precursor transport will support a better biotechnological solution to manipulate plant lignification for more efficient agricultural and industrial applications of cell wall biomass.

Liu, C.J.; Miao, Y.-C.; Zhang, K.-W.

2011-01-18T23:59:59.000Z

459

Nagarajan Vaidehi and Judith Klein-Seetharaman (eds.), Membrane Protein Structure and Dynamics: Methods and Protocols, Methods in Molecular Biology, vol. 914, DOI 10.1007/978-1-62703-023-6_14, Springer Science+Business Media, LLC 2012  

E-Print Network [OSTI]

, peptides, lipids, nucleotides, and proteins) modulate GPCR activity to affect regulation of essential physiological processes (e.g., neurotransmission, cellular metabolism, secretion, cell growth, immune defense

Goddard III, William A.

460

A membrane interferometer  

Science Journals Connector (OSTI)

...bilayer membranes from lipid monolayers. A critique . Biophys J 16 : 481 489 . Acknowledgments We thank Profs. Nick Melosh, Merritt Maduke, and Stephen White for useful insights and suggestions. The Cy5-DNA-lipid conjugate was synthesized...

Prasad V. Ganesan; Steven G. Boxer

2009-01-01T23:59:59.000Z

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


461

Wrinkling in polygonal membranes  

E-Print Network [OSTI]

boundary conditions of the polygons. When pressurised, the polygonal membranes naturally reach a parabolic shape towards their centre, the extent of which varies greatly depending on a large number of parameters, including most particularly pre...

Bonin, Arnaud Stephane

2012-02-07T23:59:59.000Z

462

Reverse Osmosis Membranes  

Science Journals Connector (OSTI)

A bibliography of citations from the U.S. National Technical Information Service data base with 183 abstracts on membranes for reverse osmosis desalination, electro-dialysis desalination and other osmotic desa...

Prof. Dr. Anthony Delyannis; Dr. Euridike-Emmy Delyannis

1980-01-01T23:59:59.000Z

463

E-Print Network 3.0 - abc transporter homology Sample Search...  

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

KELLY1... Francisco, CA 94158, USA. ABC transporter proteins couple the energy of ATP binding and hydrolysis... known ABC transporters in diseases such as cystic fibrosis...

464

Direct numerical simulation of electroconvective instability and hysteretic current-voltage response of a permselective membrane  

E-Print Network [OSTI]

We present a systematic, multiscale, fully detailed numerical modeling for dynamics of fluid flow and ion transport covering Ohmic, limiting, and overlimiting current regimes in conductance of ion-selective membrane. By ...

Pham, Van Sang

465

High Temperature Membrane Working Group  

Broader source: Energy.gov [DOE]

This presentation provides an overview of the High Temperature Membrane Working Group Meeting in May 2007.

466

Membrane fusion: Ready ? aim ? fire!  

Science Journals Connector (OSTI)

... All cells use a programme of membrane fusion and fission to assemble membranes, both internally and on their surface. Given that biological ... internally and on their surface. Given that biological membranes are essentially two-dimensional fluids, fusion must obey certain restrictions that prevent incompatible membranes from intermixing. Without such selective contact, ...

Randy Schekman

1998-12-10T23:59:59.000Z

467

Inorganic membranes: The new industrial revolution  

SciTech Connect (OSTI)

Separation systems are a vital part of most industrial processes. These systems account for a large fraction of the capital equipment used and the operating costs of industrial processes. Inorganic membranes have the potential for providing separation systems that can significantly reduce both the capital equipment and operating costs. These separation processes include waste management and recycle as well as the primary production of raw materials and products. The authors are rapidly learning to understand the effect of physical and chemical properties on the different transport mechanisms that occur in inorganic membranes. Such understanding can be expected to provide the information needed to design, engineer and manufacture inorganic membranes to produce very high separation factors for almost any separation function. To implement such a revolution, the authors need to organize a unique partnership between the national laboratories, and industry. The university can provide research to understand the materials and transport mechanisms that produce various separations, the national laboratories the development of an economical fabrication and manufacturing capability, and industry the practical understanding of the operational problems required to achieve inplementation.

Fain, D.E. [Martin Merietta Energy Systems, Oak Ridge, TN (United States)

1994-12-31T23:59:59.000Z

468

Power-law scaling in protein synthesis of a stochastic regulon  

E-Print Network [OSTI]

We investigate the protein expression pattern of the lamB gene in Escherichia coli LE392. The gene product LamB is an important membrane protein for maltose transport into cells but it is also exploited by bacteriophage lambda for infection. Although our bacterial population is clonal, stochastic gene expression leads to a majority population with a large receptor number and a minority population with a small receptor number. We find that the LamB receptor distribution p(n) of the small-n population is scale invariant with the exponent depending on growth conditions. A heuristic model is proposed that relates the observed exponent to the protein production rate.

Emily Chapman-McQuiston; Chuck Yeung; X. L. Wu

2008-08-07T23:59:59.000Z

469

Interpenetrating polymer network ion exchange membranes and method for preparing same  

DOE Patents [OSTI]

Interpenetrating polymer network ion exchange membranes include a microporous polymeric support film interpenetrated by an ion exchange polymer and are produced by absorbing and polymerizing monomers within the support film. The ion exchange polymer provides ion exchange ligands at the surface of and throughout the support film which have sufficient ligand mobility to extract and transport ions across the membrane.

Alexandratos, Spiro D. (Knoxville, TN); Danesi, Pier R. (Vienna, AT); Horwitz, E. Philip (Naperville, IL)

1989-01-01T23:59:59.000Z

470

Multi-block sulfonated poly(phenylene) copolymer proton exchange membranes  

DOE Patents [OSTI]

Improved multi-block sulfonated poly(phenylene) copolymer compositions, methods of making the same, and their use as proton exchange membranes (PEM) in hydrogen fuel cells, direct methanol fuel cells, in electrode casting solutions and electrodes. The multi-block architecture has defined, controllable hydrophobic and hydrophilic segments. These improved membranes have better ion transport (proton conductivity) and water swelling properties.

Fujimoto, Cy H. (Albuquerque, NM); Hibbs, Michael (Albuquerque, NM); Ambrosini, Andrea (Albuquerque, NM)

2012-02-07T23:59:59.000Z

471

Influence of Ibuprofen on Phospholipid Membranes  

E-Print Network [OSTI]

Basic understanding of biological membranes is of paramount importance as these membranes comprise the very building blocks of life itself. Cells depend in their function on a range of properties of the membrane, which are important for the stability and function of the cell, information and nutrient transport, waste disposal and finally the admission of drugs into the cell and also the deflection of bacteria and viruses. We have investigated the influence of ibuprofen on the structure and dynamics of L-alpha-phosphatidylcholine (SoyPC) membranes by means of grazing incidence small-angle neutron scattering (GISANS), neutron reflectometry and grazing incidence neutron spin echo spectroscopy (GINSES). From the results of these experiments we were able to determine that ibuprofen induces a two-step structuring behavior in the SoyPC films, where the structure evolves from the purely lamellar phase for pure SoyPC over a superposition of two hexagonal phases to a purely hexago- nal phase at high concentrations. Add...

Jaksch, Sebastian; Koutsioubas, Alexandros; Mattauch, Stefan; Holderer, Olaf; Ivanova, Oxana; Frielinghaus, Henrich; Hertrich, Samira; Nickel, Bert

2014-01-01T23:59:59.000Z

472

Modulation of Hepatitis C Virus Genome Replication by Glycosphingolipids and Four-Phosphate Adaptor Protein 2  

Science Journals Connector (OSTI)

...vesicles often clustered in a membranous web (MW). During infection, HCV NS5A protein...double-membrane vesicles clustered into a membranous web (MW) (17). Previous studies suggested...genome replication takes place on membranous web (MW) vesicles (17 - 19, 27) typically...

Irfan Khan; Divya S. Katikaneni; Qingxia Han; Lorena Sanchez-Felipe; Kentaro Hanada; Rebecca L. Ambrose; Jason M. Mackenzie; Kouacou V. Konan

2014-08-13T23:59:59.000Z

473

Induction of Apoptosis by Quercetin: Involvement of Heat Shock Protein  

Science Journals Connector (OSTI)

...fragmentation, and loss of membrane integrity...the induction of heat shock proteins and...in the cell cycle distribution as cells with DNA...simultaneously. Heat Shock and lISPs...and intracel lular distribution of heat shock proteins...

Yu-quan Wei; Xia Zhao; Yoshitaka Kariya; Hideki Fukata; Keisuke Teshigawara; and Atsushi Uchida

1994-09-15T23:59:59.000Z

474

Uncoupling protein-2: evidence for its function as a metabolic regulator  

Science Journals Connector (OSTI)

Uncoupling protein-2, discovered in 1997, belongs to a family of inner mitochondrial membrane proteins that, in general, function as carriers. The function(s) of uncoupling protein-2 have not yet been definitivel...

M. C. Saleh; M. B. Wheeler; C. B. Chan

2002-02-01T23:59:59.000Z

475

Protein Engineering of Bacillus thuringiensis ?-Endotoxins  

Science Journals Connector (OSTI)

Protein engineering of insecticidal Bt ?-endotoxins is a ... including increased toxicity and binding affinity, enhanced ion-transport activity, and changes in insect specificity ... . The understanding and prope...

Dr. Alvaro M. Florez; Dr. Cristina Osorio

2012-01-01T23:59:59.000Z

476

Separation of Olefin/Paraffin Mixtures with Carrier Facilitated Membrane Final Report  

SciTech Connect (OSTI)

This document describes the results of a DOE funded joint effort of Membrane Technology and Research Inc. (MTR), SRI International (SRI), and ABB Lummus (ABB) to develop facilitated transport membranes for olefin/paraffin separations. Currently, olefin/paraffin separation is done by distillationan extremely energy-intensive process because of the low relative volatilities of olefins and paraffins. If facilitated transport membranes could be successfully commercialized, the potential energy savings achievable with this membrane technology are estimated to be 48 trillion Btu per year by the year 2020. We discovered in this work that silver salt-based facilitated transport membranes are not stable even in the presence of ideal olefin/paraffin mixtures. This decline in membrane performance appears to be caused by a previously unrecognized phenomenon that we have named olefin conditioning. As the name implies, this mechanism of performance degradation becomes operative once a membrane starts permeating olefins. This project is the first study to identify olefin conditioning as a significant factor impacting the performance of facilitated olefin transport membranes. To date, we have not identified an effective strategy to mitigate the impact of olefin conditioning. other than running at low temperatures or with low olefin feed pressures. In our opinion, this issue must be addressed before further development of facilitated olefin transport membranes can proceed. In addition to olefin conditioning, traditional carrier poisoning challenges must also be overcome. Light, hydrogen, hydrogen sulfide, and acetylene exposure adversely affect membrane performance through unwanted reaction with silver ions. Harsh poisoning tests with these species showed useful membrane lifetimes of only one week. These tests demonstrate a need to improve the stability of the olefin complexing agent to develop membranes with lifetimes satisfactory for commercial application. A successful effort to improve membrane coating solution stability resulted in the finding that membrane performance loss could be reversed for all poisoning cases except hydrogen sulfide exposure. This discovery offers the potential to extend membrane lifetime through cyclic regeneration. We also found that certain mixed carriers exhibited greater stability in reducing environments than exhibited by silver salt alone. These results offer promise that solutions to deal with carrier poisoning are possible. The main achievement of this program was the progress made in gaining a more complete understanding of the membrane stability challenges faced in the use of facilitated olefin transport membranes. Our systematic study of facilitated olefin transport uncovered the full extent of the stability challenge, including the first known identification of olefin conditioning and its impact on membrane development. We believe that significant additional fundamental research is required before facilitated olefin transport membranes are ready for industrial implementation. The best-case scenario for further development of this technology would be identification of a novel carrier that is intrinsically more stable than silver ions. If the stability problems could be largely