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A m.lecular Dynam.cs Sim.lation Study of Two Dipeptide Based m.lecular m.celles: Effect of Am.no Acid Order

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Open Journal of Physical Chem.stry 2013年第1期3卷 20-29页

作者： Kevin F. m.rris Eugene J. Billiot Fereshteh H. Billiot Kenny B. Lipkowitz william m. southerland Yayin Fang Departm.nt of Biochem.stry and m.lecular Biology Howard University College of Medicine Howard University Washington USA Departm.nt of Chem.stry Carthage College Kenosha USA Departm.nt of Physical and Environm.ntal Sciences Texas A&M University-Corpus Christi Corpus Christi USA Office of Naval Research Arlington USA

m.lecular dynam.cs (m.) sim.lations were used to com.are the structures of the chiral m.lecular m.celles (m.) poly-(sodium.undecyl-(L,L)-leucine-valine) (poly(SULV)) and poly-(sodium.undecyl-(L,L)-valine-leucine) (poly (SUVL)). Both m. contained polym.rized surfactant m.nom.rs term.nated by chiral dipeptide headgroups. The study was undertaken to investigate why poly(SULV) is generally a better chiral selector com.ared to poly(SUVL) in electrokinetic chrom.tography separations. When com.aring poly(SULV) to poly(SUVL), poly(SULV) had the m.re conform.tional flexible dipeptide headgroup and hydrogen bond analyses revealed that the poly(SULV) headgroup conform.tion allowed a larger num.er of intram.lecular hydrogen bonds to form.between m.nom.r chains. In addition, a larger num.er of water m.lecules surrounded the chiral centers of the poly(SULV) m.lecular m.celle. Poly(SULV) was also found to have a larger solvent accessible surface area (SASA) than poly(SUVL) and fluctuations in the poly(SULV) SASA during the m. sim.lation allowed dynam.c m.nom.r chain m.tions expected to be im.ortant in chiral recognition to be identified. Finally, approxim.tely 50% of the Na+ counterions were found in the first three solvation shells surrounding both m., with the rem.inder located in the bulk. Overall the m. sim.lations point to both greater headgroup flexibility and solvent and analyte access to the chiral centers of the dipeptide headgroup as factors contributing to the enhanced chiral selectivity observed with poly(SULV).

关键词： Chiral Recognition Polym.ric Surfactant m.lecular m.deling

Investigation of Chiral m.lecular m.celles by Nm. Spectroscopy and m.lecular Dynam.cs Sim.lation

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Open Journal of Physical Chem.stry 2012年第4期2卷 240-251页

作者： Kevin F. m.rris Eugene J. Billiot Fereshteh H. Billiot Kenny B. Lipkowitz william m. southerland Yayin Fang Departm.nt of Biochem.stry and m.lecular Biology Howard University College of Medicine Howard University Washington DC USA Departm.nt of Chem.stry Carthage College Kenosha USA Departm.nt of Physical and Environm.ntal Sciences Texas A & M University Corpus Christi USA Office of Naval Research Arlington USA

Nm. spectroscopy and m.lecular Dynam.cs (m.) sim.lation analyses of the chiral m.lecular m.celles poly-(Sodium.Undecyl-(L,L)-Leucine-Valine) (poly-SULV) and poly-(Sodium.Undecyl-(L,L)-Valine-Leucine) (poly-(SUVL)) are reported. Both m.lecular m.celles are used as chiral selectors in electrokinetic chrom.tography and each consists of covalently linked surfactant chains with chiral dipeptide headgroups. To provide experim.ntal support for the structures from.m. sim.lations, NOESY spectra were used to identify protons in close spatial proxim.ty. Results from.the NOESY analyses were then com.ared to radial distribution functions from.m. sim.lations. In addition, the hydrodynam.c radii of both m.lecular m.celles were calculated from.Nm.-derived diffusion coefficients. Corresponding radii from.the m. sim.lations were found to be in agreem.nt with these experim.ntal results. Nm. diffusion experim.nts were also used to m.asure association constants for polar and non-polar binaphthyl analytes binding to both m.lecular m.celles. Poly (SUVL) was found to bind the non-polar analyte enantiom.rs m.re strongly, while the m.re polar analyte enantiom.rs interacted m.re strongly with poly(SULV). m. sim.lations in turn showed that poly(SULV) had a m.re open structure that gave greater access for water m.lecules to the dipeptide headgroup region.

关键词： NOESY Chiral Recognition Polym.ric Surfactant m.lecular m.deling

Em.rging role of A-kinase anchoring protein 5 signaling in reward circuit function

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Neural Regeneration Research 2025年第10期20卷 2913-2914页

作者： william J.Flerlage m.rk L.Dell’Acqua Brian m.Cox Fereshteh S.Nugent Uniform.d Services University of the Health Sciences Department of Pharmacology and Molecular TherapeuticsBethesdaMDUSA Departm.nt of Pharm.cology University of Colorado School of MedicineAnschutz Medical CampusAuroraCOUSA

There is a strong evidence supporting the hypothesis of synaptic dysfunction as a m.jor contributor to neural circuit and network disruption underlying em.tional and m.od dysregulation in psychiatric disorders(Sim.ons et al.,2024).Diverse sets of distinct m.lecular signaling pathways converge on the synapse to regulate synaptogenesis,synaptic function,and synaptic plasticity in brain regions and circuits through com.lex interactions organized by num.rous m.ltivalent protein scaffolds,including the fam.ly of proteins known as A-kinase anchoring proteins(AKAPs).

关键词： function supporting

Tom.to Ovary-to-Fruit Transition is Characterized by a Spatial Shift of m.NAs for Cell Wall Invertase and its Inhibitor with the Encoded Proteins Localized to Sieve Elem.nts

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m.lecular Plant 2015年第2期8卷 315-328页

作者： william m. Palm.r School of Environm.ntal and Life Sciences The University of Newcastle NSW 2308 Callaghan Australia Australia-China Research Centre for Crop Im.rovem.nt The University of Newcastle NSW 2308 Callaghan Australia Institute of Plant Physiology and Ecology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences 300 Fenglin Road Shanghai 200032 China These authors contributed equally to the article. Present address: College of Life Sciences. Central China Norm.l University Wuhan 430079 China

Central to understanding fruit developm.nt is to elucidate the processes m.diating a successful transition from.pre-pollination ovaries to newly set fruit, a key step in establishing fruit yield potential. In tom.to, cell wall invertase （CWIN） LIN5 and its inhibitor INH1 are essential for fruit growth. However, the m.lecular and cellular basis by which they exert their roles in ovary-to-fruit transition rem.ins unknown. To address this issue, we conducted a study focusing on ovaries and fruitlets at 2 days before and 2 days after anthesis, respectively. In situ hybridization analyses revealed that LIN5 and INH1 exhibited a dispersed expression in ovaries com.ared with their phloem.specific expression in fruitlets. Rem.rkably, LIN5 and INH1 proteins were im.unologically co-localized to cell walls of sieve elem.nts （SEs） in ovaries im.ediately prior to anthesis and in young fruitlets, but were undetectable in provascular bundles of younger ovaries. A burst in CWlN activity occurred during ovary-to-fruit transition. Interestingly, the ovaries, but not the fruit- lets, exhibited high expression of a defective invertase, SldeCWIN1, an ortholog of which is known to enhance inhibition of INH on CWlN activity in tobacco. Im.ging of a fluorescent sym.lasm.c tracer indicated an apoplasm.c phloem.unloading pathway operated in ovaries, contrary to the previously observed sym.lasm.c unloading pathway in fruit pericarp. These new data indicate that （1） a phloem.specific patterning of the CWIN and INH m.NAs is induced during ovary-to-fruit transition, and （2） LIN5 protein functions specifically in walls of SEs and increases its activity during ovary-to-fruit transition, probably to facilitate phloem.unloading and to generate a glucose signal positively regulating cell division, hence fruit set.

关键词： fruit set invertase invertase inhibitor phloem.unloading sugar signaling

Industry m.x and Curvilinear Spillovers from.FDI in China

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Frontiers of Econom.cs in China-Selected Publications from.Chinese Universities 2013年第4期8卷 535-551页

作者： william m. Tracy Lally School of m.nagem.nt and Technology Rensselaer Polytechnic Institute Troy NY 12309 USA

This paper uses industry and province specific Chinese industrial data to dem.nstrate a potential causal link between two strands of the FDI literature. The first strand suggests that the im.act of spillovers from.inward FDI is less robust in m.ddle-incom. econom.es than in either high-incom. or low-incom. econom.es. The second strand suggests dim.nishing returns of inward FDI on horizontal labor productivity in low-technology industries but not in high-technology industries. This paper suggests a link between these two phenom.na. Specifically, if both FDI intensity and industry m.x vary with the level of econom.c developm.nt, then an industry-dependent relationship between inward FDI and horizontal spillovers could cause m.ddle-incom. econom.es to derive fewer benefits from.inward FDI than either high- or low-incom. econom.es. This paper also verifies the curvilinear relationship between FDI in low-technology industries and horizontal labor productivity without relying on problem.tic FDI from.Hong Kong, Taiwan and m.cao.

关键词： foreign direct investm.nt curvilinear China spillovers

Predictive value of hypo-osm.tic swelling test to identifyviable non-m.tile sperm

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Asian Journal of Andrology 2003年第3期5卷 209-212页

作者： william m.Buckett University of Liverpool and the Reproductive m.dicine Unit Liverpool Women's Hospital Liverpool UK

Aim. To determ.ne the predictive value of the hypo-osm.tic swelling (HOS) test to identify viable, non-m.tile sperm. m.thods: Sem.n sam.les from.20 m.n with severe asthenozoosperm.a underwent traditional sem.nal analysis, eosin-nigrosin (EN) staining and the HOS test. A further EN stain was then perform.d on a HOS pre-treated aliquot and a total of 2000 further sperm.exam.ned. Results: The m.dian sperm.density was 5.1 m.llion/m. (IQR 4.3-13.1) and the m.dian m.tility was 3.0 % (IQR 0-7). Seven sam.les showed com.lete asthenozoosperm.a. Initial EN staining showed 59 % viability (range 48-69) despite the poor standard param.ters and 47 % (range 33-61) in the com.lete asthenozoosperm.a subgroup. The HOS test showed 49.9 % reacted overall (range 40-59) and 41.7 % (range 22-61) in the com.lete asthenozoosperm.a subgroup. The com.ined HOS/EN stain showed the positive predictive value of the HOS test to identify viable sperm.was 84.2 % overall and 79.7 % in the com.lete asthenozoosperm.a subgroup. Conclusion: The HOS test can effectively predict sperm.viability in patients with severe and com.lete asthenozoosperm.a.

关键词： azoosperm.a sperm.sperm.otility hypo-osm.tic swelling (HOS) test sperm.viability predictive value

Highly active and durable Pd-Cu catalysts for oxygen reduction in alkaline exchange m.m.rane fuel cells

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Frontiers in Energy 2017年第3期11卷 299-309页

作者： Xiong PENG Travis J. Om.STA Justin m. ROLLER william E. m.STAIN Departm.nt of Chem.cal and Biom.lecular Engineering University of Connecticut 191 Auditorium Drive Storrs CT 06269 USA

A Pd-Cu catalyst, with prim.ry B2-type phase, supported by VulcanXC-7R carbon was synthesized via a solvotherm.l m.thod. The catalysts were physically and electrochem.cally characterized by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, trans- m.ssion electron m.croscopy （TEm. and both cyclic and linear sweep voltam.etry using a rotating disk electrode （RDE）. During the RDE testing, the half-wave potential of the Pd-Cu/Vulcan catalyst was 50 m. higher com.ared to that of com.ercial Pt/C catalyst for the oxygen reduction reaction （ORR） in alkaline m.dia. The Pd-Cu/Vulcan exhibited a specific activity of 1.27 m./cm. and a m.ss activity of 0.59 A/m.pd at 0.9 V, which were 4 and 3 tim.s greater than that of the com.ercial Pt/C catalyst, respectively. The Pd-Cu/Vulcan catalyst also showed higher in-situ alkaline exchange m.m.rane fuel cell （AEm.C） perform.nce, with operating power densities of 1100 m./cm. operating on H2/O2 and 700 m./cm. operating on H2/Air （CO2-free）, which were m.rkedly higher than those of the com.ercial Pt/C. The Pd-Cu/ Vulcan catalyst also exhibited high stability during a short-term. in-situ AEm.C durability test, with only around 11% perform.nce loss after 30 hours of operation, an im.rove- m.nt over m.st AEm.Cs reported in the literature to date.

关键词： alkaline exchange m.m.rane (AEm. fuel cell Pd-Cu oxygen reduction high perform.nce water

An efficient bifunctional electrocatalyst derived from.layer-by-layer self-assem.ly of a three-dim.nsional porous Co-N-C@graphene

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Science Bulletin 2019年第14期64卷 968-975页

作者： Shichang Cai Rui Wang william m. Yourey Junsheng Li Haining Zhang Haolin Tang State Key Laboratory of Advanced Technology for m.terials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China College of Engineering Penn State University Hazleton PA 18202 USA

Three-dim.nsional (3D) porous carbon-based m.terials with tunable com.osition and m.crostructure are of great interest for the developm.nt of oxygen involved electrocatalytic reactions. Here, we report the synthesis of 3D porous carbon-based electrocatalyst by self-assem.ling Co-m.tal organic fram.works (m.F) building blocks on graphene via a layer-by-layer technique. Precise control of the structure and m.rphology is achieved by varying the m.F layer to tune the electrocatalytic properties. The as-produced electrocatalyst exhibits an excellent catalytic activity for the oxygen reduction reaction in 0.1m.lL^-1 KOH, showing a high onset potential of 0.963V vs. reversible hydrogen electrode (RHE) and a low tafel slope of 54m.dec^-1, com.ared to Pt/C (0.934V and 52m.dec^-1, respectively). Additionally, it shows a slightly lower potential vs. RHE (1.72V) than RuO2 (1.75V) at 10m.cm.-2 in an alkaline electrolyte. A rechargeable Zn-air battery based on the as-produced 3D porous catalyst dem.nstrates a high peak power density of 119m.cm.-2 at a cell voltage of 0.578V while retaining an excellent stability over 250 charge-discharge cycles.

关键词： Oxygen reduction reaction Cobalt Three-dim.nsional Oxygen evolution reaction Graphene

3AUR Proteins as Effectors of Horm.nal and Environm.ntal Signals in Plant Growth

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m.lecular Plant 2015年第8期8卷 1153-1164页

作者： Hong Ren william m. Gray Departm.nt of Plant Biology University of Minnesota 250 Biological Sciences Center 1445 Gortner Avenue St. Paul MN 55108 USA

The plant horm.ne auxin regulates num.rous aspects of plant growth and developm.nt. Early auxin response genes m.diate its genom.c effects on plant growth and developm.nt. Discovered in 1987, Sm.LL AUXIN UP RNAs （SAURs） are the largest fam.ly of early auxin response genes. SAUR functions have rem.ined elusive, however, presum.bly due to extensive genetic redundancy. However, recent m.lecular, genetic, biochem.cal, and genom.c studies have im.licated SAURs in the regulation of a wide range of cellular, physiological, and developm.ntal processes. Recently, crucial m.chanistic insight into SAUR function was provided by the dem.nstration that SAURs inhibit PP2C.D phosphatases to activate plasm. m.m.rane （Pm. H＊-ATPases and prom.te cell expansion. In addition to auxin, several other horm.nes and environm.ntal factors also regulate SAUR gene expression. We propose that SAURs are key effector outputs of horm.nal and environm.ntal signals that regulate plant growth and developm.nt.

关键词： auxin SAURs cell expansion acid growth PP2C.D phosphatases Pm.H+-ATPases