Surface-wave-enabled darkfield aperture for background suppression during weak signal detection.

abstract：:Natural products have long served as both a source and inspiration for pharmaceuticals. Modifying the structure of a natural product often improves the biological activity of the compound. Metabolic engineering strategies to ferment "unnatural" products have been enormously successful in microbial organisms. However, ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Runguphan W,Maresh JJ,O'Connor SE

更新日期：2009-08-18 00:00:00

abstract：:The complete amino acid and DNA sequences of the human 40-kDa keratin are reported. The DNA sequence encodes a protein of 44,098 Da, which is unique in that it lacks the terminal non-alpha-helical tail segment found in all other keratins. When the human 40-kDa keratin amino acid sequence is compared to the correspondi...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Eckert RL

更新日期：1988-02-01 00:00:00

abstract：:Significant liquid-structure theory has been used to calculate the transport properties of the alkali metals. Unlike previous calculations, the volume and temperature dependence of the solid-like structure has been taken into consideration. Equations for the potential energy as a function of volume of the alkali metal...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Hsu CC,Eyring H

更新日期：1972-06-01 00:00:00

abstract：:The regulatory photoreceptor phytochrome controls the transcription of its own phy genes in a negative feedback fashion. We have exploited microprojectile-mediated gene transfer to develop a rapid transient expression assay system for the study of DNA sequences involved in the phytochrome-regulated expression of these...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Bruce WB,Christensen AH,Klein T,Fromm M,Quail PH

更新日期：1989-12-01 00:00:00

abstract：:It is shown that, under certain standard assumptions, such as extended Riemann hypotheses, the scattering matrix varphi(s) for generic Gamma

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Deshouillers JM,Iwaniec H,Phillips RS,Sarnak P

更新日期：1985-06-01 00:00:00

abstract：:Sea urchins are a major component of recent marine communities where they exert a key role as grazers and benthic predators. However, their impact on past marine organisms, such as crinoids, is hard to infer in the fossil record. Analysis of bite mark frequencies on crinoid columnals and comprehensive genus-level dive...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Gorzelak P,Salamon MA,Baumiller TK

更新日期：2012-05-01 00:00:00

abstract：:Aspartic acid in the second transmembrane domain is a highly conserved amino acid among the G protein-coupled receptors and is functionally important for agonist binding and G-protein coupling in beta 2-adrenergic and luteinizing hormone receptors. To determine whether this aspartic acid is also involved in the functi...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Bihoreau C,Monnot C,Davies E,Teutsch B,Bernstein KE,Corvol P,Clauser E

更新日期：1993-06-01 00:00:00

abstract：:The beta-1,3-glucan recognition protein (betaGRP)/Gram-negative bacteria-binding protein 3 (GNBP3) is a crucial pattern-recognition receptor that specifically binds beta-1,3-glucan, a component of fungal cell walls. It evokes innate immunity against fungi through activation of the prophenoloxidase (proPO) cascade and ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Takahasi K,Ochiai M,Horiuchi M,Kumeta H,Ogura K,Ashida M,Inagaki F

更新日期：2009-07-14 00:00:00

abstract：:Single molecule atomic force microscopy was used to characterize structure, binding strength (unbinding force), and binding kinetics of a classical cadherin, vascular endothelial (VE)-cadherin, secreted by transfected Chinese hamster ovary cells as cis-dimerized full-length external domain fused to Fc-portion of human...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Baumgartner W,Hinterdorfer P,Ness W,Raab A,Vestweber D,Schindler H,Drenckhahn D

更新日期：2000-04-11 00:00:00

abstract：:It is well known from Hardin's "Tragedy of the Commons" [Hardin G (1968) Science 162:1243-1248] that, if open access is allowed, overgrazing typically results. Hardin, and most authors of the subsequent literature, adopted a static view of the underlying ecosystem. Here we extend this tragedy of the commons to conside...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Brekke KA,Øksendal B,Stenseth NC

更新日期：2007-09-11 00:00:00

abstract：:Tumor-infiltrating lymphocytes (TIL) obtained from human melanomas can specifically lyse autologous tumor in vitro and mediate tumor regression in vivo. To develop more effective therapeutic reagents and to further understand the T-cell response to tumors, the diversity of T-cell receptors (TCRs) involved in melanoma ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Shilyansky J,Nishimura MI,Yannelli JR,Kawakami Y,Jacknin LS,Charmley P,Rosenberg SA

更新日期：1994-03-29 00:00:00

abstract：:The primary obstacle to producing renewable fuels from lignocellulosic biomass is a plant's recalcitrance to releasing sugars bound in the cell wall. From a sample set of wood cores representing 1,100 individual undomesticated Populus trichocarpa trees, 47 extreme phenotypes were selected across measured lignin conten...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Studer MH,DeMartini JD,Davis MF,Sykes RW,Davison B,Keller M,Tuskan GA,Wyman CE

更新日期：2011-04-12 00:00:00

abstract：:We have identified a subset of CD56(+)CD3(-) human natural killer (NK) cells that express CD4 and the HIV coreceptors CCR5 and CXCR4. These cells can be productively infected in vitro by both CCR5- and CXCR4-using molecular clones of HIV-1 in a CD4-dependent manner. Analysis of HIV-infected persons showed that viral D...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Valentin A,Rosati M,Patenaude DJ,Hatzakis A,Kostrikis LG,Lazanas M,Wyvill KM,Yarchoan R,Pavlakis GN

更新日期：2002-05-14 00:00:00

abstract：:Explaining the maintenance of tropical forest diversity under the countervailing forces of drift and competition poses a major challenge to ecological theory. Janzen-Connell effects, in which host-specific natural enemies restrict the recruitment of juveniles near conspecific adults, provide a potential mechanism. Jan...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Levi T,Barfield M,Barrantes S,Sullivan C,Holt RD,Terborgh J

更新日期：2019-01-08 00:00:00

abstract：:Fisheries-induced evolution and its impact on the productivity of exploited fish stocks remains a highly contested research topic in applied fish evolution and fisheries science. Although many quantitative models assume that larger, more fecund fish are preferentially removed by fishing, there is no empirical evidence...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Sutter DA,Suski CD,Philipp DP,Klefoth T,Wahl DH,Kersten P,Cooke SJ,Arlinghaus R

更新日期：2012-12-18 00:00:00

abstract：:We measured the dependence of the variance in the rotation rate of tethered cells of Escherichia coli on the mean rotation rate over a regime in which the motor generates constant torque. This dependence was compared with that of broken motors. In either case, motor torque was augmented with externally applied torque....

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Samuel AD,Berg HC

更新日期：1995-04-11 00:00:00

abstract：:Preference behaviors are often established during early life, but the underlying neural circuit mechanisms remain unknown. Adapting a unique nesting behavior assay, we confirmed a "critical period" for developing music preference in C57BL/6 mice. Early music exposure between postnatal days 15 and 24 reversed their inn...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Yang EJ,Lin EW,Hensch TK

更新日期：2012-10-16 00:00:00

abstract：:A conformational isoform of the mammalian prion protein (PrP(Sc)) is the sole component of the infectious pathogen that causes the prion diseases. We have obtained X-ray fiber diffraction patterns from infectious prions that show cross-beta diffraction: meridional intensity at 4.8 A resolution, indicating the presence...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Wille H,Bian W,McDonald M,Kendall A,Colby DW,Bloch L,Ollesch J,Borovinskiy AL,Cohen FE,Prusiner SB,Stubbs G

更新日期：2009-10-06 00:00:00

abstract：:Domestic animals can be cloned using techniques such as embryo splitting and nuclear transfer to produce genetically identical individuals. Although embryo splitting is limited to the production of only a few identical individuals, nuclear transfer of donor nuclei into recipient oocytes, whose own nuclear DNA has been...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Keefer CL

更新日期：2015-07-21 00:00:00

abstract：:Hepatitis C virus (HCV) is a major cause of liver disease, affecting over 2% of the world's population. The HCV envelope glycoproteins E1 and E2 mediate viral entry, with E2 being the main target of neutralizing antibody responses. Structural investigations of E2 have produced templates for vaccine design, including t...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Kong L,Lee DE,Kadam RU,Liu T,Giang E,Nieusma T,Garces F,Tzarum N,Woods VL Jr,Ward AB,Li S,Wilson IA,Law M

更新日期：2016-11-08 00:00:00

abstract：:We describe a quantum mechanics/molecular mechanics investigation of the guanidinoacetate methyltransferase catalyzed reaction, which shows that proton transfer from guanidinoacetate (GAA) to Asp-134 and methyl transfer from S-adenosyl-L-methionine (AdoMet) to GAA are concerted. By self-consistent-charge density funct...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Zhang X,Bruice TC

更新日期：2006-10-31 00:00:00

abstract：:Neurog3 (Neurogenin 3 or Ngn3) is both necessary and sufficient to induce endocrine islet cell differentiation from embryonic pancreatic progenitors. Since robust Neurog3 expression has not been detected in hormone-expressing cells, Neurog3 is used as an endocrine progenitor marker and regarded as dispensable for the ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Wang S,Jensen JN,Seymour PA,Hsu W,Dor Y,Sander M,Magnuson MA,Serup P,Gu G

更新日期：2009-06-16 00:00:00

abstract：:Mutations in copper/zinc superoxide dismutase (SOD1) are causative for dominantly inherited amyotrophic lateral sclerosis (ALS). Despite high variability in biochemical properties among the disease-causing mutants, a proportion of both dismutase-active and -inactive mutants are stably bound to spinal cord mitochondria...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Vande Velde C,Miller TM,Cashman NR,Cleveland DW

更新日期：2008-03-11 00:00:00

abstract：:We describe an algorithm to compute trisections of orientable four-manifolds using arbitrary triangulations as input. This results in explicit complexity bounds for the trisection genus of a 4-manifold in terms of the number of pentachora (4-simplices) in a triangulation. ...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Bell M,Hass J,Rubinstein JH,Tillmann S

更新日期：2018-10-23 00:00:00

abstract：:In myocardial ischemia, adrenergic nerves release excessive amounts of norepinephrine (NE), causing dysfunction and arrhythmias. With anoxia and the concomitant ATP depletion, vesicular storage of NE is impaired, resulting in accumulation of free NE in the axoplasm of sympathetic nerves. Intraneuronal acidosis activat...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Silver RB,Mackins CJ,Smith NC,Koritchneva IL,Lefkowitz K,Lovenberg TW,Levi R

更新日期：2001-02-27 00:00:00

abstract：:We used integrin alphaLbeta2 heterodimers containing I domains locked open (active) or closed (inactive) with disulfide bonds to investigate regulatory interactions among domains in integrins. mAbs to the alphaL I domain and beta2 I-like domain inhibit adhesion of wild-type alphaLbeta2 to intercellular adhesion molecu...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Lu C,Shimaoka M,Zang Q,Takagi J,Springer TA

更新日期：2001-02-27 00:00:00

abstract：:Purified human platelet-derived growth factor (PDGF) induces an increase in amino acid uptake via system A in quiescent human diploid fibroblasts. Cells must be exposed to PDGF for 45 min to obtain maximum transport stimulation. Transport stimulation requires protein synthesis. Transient exposure to PDGF, alone, in th...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Owen AJ 3rd,Geyer RP,Antoniades HN

更新日期：1982-05-01 00:00:00

abstract：:Precise regulation of the evolutionarily conserved hypoxia-inducible transcription factor (HIF) ensures proper adaptation to variations in oxygen availability throughout development and into adulthood. Oxygen-dependent regulation of HIF stability and activity are mediated by hydroxylation of conserved proline and aspa...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Dann CE 3rd,Bruick RK,Deisenhofer J

更新日期：2002-11-26 00:00:00

abstract：:General optimization results from physics indicate that maximum efficiency of a process, in the sense of minimum overall entropy production, is achieved when the rate of entropy production is constant over time, however not in ordinary clock time but on an, in general varying, "eigen time" scale, intrinsic to the syst...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Andresen B,Shiner JS,Uehlinger DE

更新日期：2002-04-30 00:00:00

abstract：:If climate change outpaces the rate of adaptive evolution within a site, populations previously well adapted to local conditions may decline or disappear, and banked seeds from those populations will be unsuitable for restoring them. However, if such adaptational lag has occurred, immigrants from historically warmer c...

journal_title：Proceedings of the National Academy of Sciences of the United States of America

authors： Wilczek AM,Cooper MD,Korves TM,Schmitt J

更新日期：2014-06-03 00:00:00