Assembly of complex cell microenvironments using geometrically docked hydrogel shapes.

abstract：:Dopaminergic and glutamatergic neurotransmissions in the striatum play an essential role in motor- and reward-related behaviors. Dysfunction of these neurotransmitter systems has been found in Parkinson's disease, schizophrenia, and drug addiction. Cyclin-dependent kinase 5 (CDK5) negatively regulates postsynaptic sig...

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

authors： Chergui K,Svenningsson P,Greengard P

更新日期：2004-02-17 00:00:00

abstract：:Determinants of the recommended dietary allowance (RDA) for vitamin C include the relationship between vitamin C dose and steady-state plasma concentration, bioavailability, urinary excretion, cell concentration, and potential adverse effects. Because current data are inadequate, an in-hospital depletion-repletion stu...

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

authors： Levine M,Conry-Cantilena C,Wang Y,Welch RW,Washko PW,Dhariwal KR,Park JB,Lazarev A,Graumlich JF,King J,Cantilena LR

更新日期：1996-04-16 00:00:00

abstract：:Recent excavations at Pre-Pottery Neolithic A (PPNA) WF16 in southern Jordan have revealed remarkable evidence of architectural developments in the early Neolithic. This sheds light on both special purpose structures and "domestic" settlement, allowing fresh insights into the development of increasingly sedentary comm...

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

authors： Finlayson B,Mithen SJ,Najjar M,Smith S,Maričević D,Pankhurst N,Yeomans L

更新日期：2011-05-17 00:00:00

abstract：:The functions of individual basal transcription factors during the formation of an initiation complex by RNA polymerase II remain largely unknown. Transcription factor IIE (TFIIE) has recently been shown to bind to multiple targets in the initiation complex. To assess the role of zinc binding in basal transcription, w...

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

authors： Maxon ME,Tjian R

更新日期：1994-09-27 00:00:00

abstract：:Enkephalins, a group of small peptides with opiate-like activity, have been defined originally as neuropeptides. Recent reports showed, using in situ hybridization, that the enkephalin-encoding gene, proenkephalin A (pEnkA), is expressed in nondifferentiated cells of diverse mesodermal lineages. The transient expressi...

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

authors： Rosen H,Polakiewicz RD,Benzakine S,Bar-Shavit Z

更新日期：1991-05-01 00:00:00

abstract：:Spatial organization of the binding sites for the priming substrate, the template DNA, and the transcription inhibitor rifampicin (Rif) in Escherichia coli RNA polymerase (EC 2.7.7.6) was probed with chimeric compounds in which Rif is covalently attached to a ribonucleotide. The compounds bind to RNA polymerase in bif...

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

authors： Mustaev A,Zaychikov E,Severinov K,Kashlev M,Polyakov A,Nikiforov V,Goldfarb A

更新日期：1994-12-06 00:00:00

abstract：:The concept of contagion has steadily expanded from its original grounding in epidemic disease to describe a vast array of processes that spread across networks, notably social phenomena such as fads, political opinions, the adoption of new technologies, and financial decisions. Traditional models of social contagion ...

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

authors： Ugander J,Backstrom L,Marlow C,Kleinberg J

更新日期：2012-04-17 00:00:00

abstract：:Recognition of a particular individual occurs when we reactivate links between current perceptual inputs and the previously formed representation of that person. This recognition can be achieved by identifying, separately or simultaneously, distinct elements such as the face, silhouette, or voice as belonging to one i...

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

authors： Sliwa J,Duhamel JR,Pascalis O,Wirth S

更新日期：2011-01-25 00:00:00

abstract：:In an era of large-scale science-related challenges and rapid advancements in groundbreaking science with major societal implications, communicating about science is critical. The profile of science communication has increased over the last few decades, with multiple sectors calling for such activities. As scientists ...

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

authors： Rose KM,Markowitz EM,Brossard D

更新日期：2020-01-21 00:00:00

abstract：:We present a synthetic adaptation of the fibrillar adhesion surfaces found in nature. The structure consists of protruding fibrils topped by a thin plate and shows an experimentally measured enhancement in adhesion energy of up to a factor of 9 over a flat control. Additionally, this structure solves the robustness pr...

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

authors： Glassmaker NJ,Jagota A,Hui CY,Noderer WL,Chaudhury MK

更新日期：2007-06-26 00:00:00

abstract：:Homeobox genes constitute a large family of transcription factors that are essential during normal development and are often dysregulated in cancer. However, the molecular mechanisms by which homeobox genes influence cancer remain largely unknown. Here we show that the tissue-restricted cyclin A1 is a transcriptional ...

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

authors： Coletta RD,Christensen K,Reichenberger KJ,Lamb J,Micomonaco D,Huang L,Wolf DM,Müller-Tidow C,Golub TR,Kawakami K,Ford HL

更新日期：2004-04-27 00:00:00

abstract：:Histone modifications are regarded as the most indispensible phenomena in epigenetics. Of these modifications, lysine methylation is of the greatest complexity and importance as site- and state-specific lysine methylation exerts a plethora of effects on chromatin structure and gene transcription. Notably, paramecium b...

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

authors： Wei H,Zhou MM

更新日期：2010-10-26 00:00:00

abstract：:Following carcinogen exposure in vitro, normal rat tracheal epithelial cells are transformed in a multistage process in which the cultured cells become immortal and, ultimately, neoplastic. Five cell lines derived from tumors produced by neoplastically transformed rat tracheal epithelial cells were examined for the ex...

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

authors： Walker C,Nettesheim P,Barrett JC,Gilmer TM

更新日期：1987-04-01 00:00:00

abstract：:Upon release from the anther, pollen grains of angiosperm flowers are exposed to a dry environment and dehydrate. To survive this process, pollen grains possess a variety of physiological and structural adaptations. Perhaps the most striking of these adaptations is the ability of the pollen wall to fold onto itself to...

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

authors： Katifori E,Alben S,Cerda E,Nelson DR,Dumais J

更新日期：2010-04-27 00:00:00

abstract：:Extracellular stimuli regulate neuronal differentiation and subtype specification during brain development, although the intracellular signaling pathways that mediate these processes remain largely unclear. We now show that the PDK1-Akt pathway regulates differentiation of telencephalic neural precursor cells (NPCs). ...

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

authors： Oishi K,Watatani K,Itoh Y,Okano H,Guillemot F,Nakajima K,Gotoh Y

更新日期：2009-08-04 00:00:00

abstract：:Rats were raised after weaning on a vitamin D-deficient diet which used whole wheat and casein as the major protein source. For at least the first year of life, plasma calcium concentrations of these rats were the same as those of vitamin D-replete rats, and the rate of growth was normal for at least 6 months. The fol...

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

authors： Lester GE,VanderWiel CJ,Gray TK,Talmage RV

更新日期：1982-08-01 00:00:00

abstract：:We report on the location of the chain part of the retinylidene chromophore in the projected density of bacteriorhodopsin as determined by neutron diffraction from the two-dimensional purple membrane lattice. For this purpose, partially deuterated retinal was synthesized containing 10 deuterons at positions C-8, C-10,...

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

authors： Seiff F,Wallat I,Ermann P,Heyn MP

更新日期：1985-05-01 00:00:00

abstract：:In the mammalian retina, extensive processing of spatiotemporal and chromatic information occurs. One key principle in signal transfer through the retina is parallel processing. Two of these parallel pathways are the ON- and OFF-channels transmitting light and dark signals. This dual system is created in the outer ple...

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

authors： Hack I,Peichl L,Brandstätter JH

更新日期：1999-11-23 00:00:00

abstract：:Fluorescence in situ hybridization (FISH) is a powerful tool for physical mapping in human and other mammalian species. However, application of the FISH technique has been limited in plant species, especially for mapping single- or low-copy DNA sequences, due to inconsistent signal production in plant chromosome prepa...

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

authors： Jiang J,Gill BS,Wang GL,Ronald PC,Ward DC

更新日期：1995-05-09 00:00:00

abstract：:The charge-stabilization effect associated with alpha-helices in proteins has been reexamined by microscopic calculations without any a priori assumptions about the dielectric constant of the protein. The calculations reproduce the observed charge stabilization effect of a helix in two well-defined test cases: a histi...

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

authors： Aqvist J,Luecke H,Quiocho FA,Warshel A

更新日期：1991-03-01 00:00:00

abstract：:Microbes whose genomes are encoded by DNA and for which adequate information is available display similar genomic mutation rates (average 0.0034 mutations per chromosome replication, range 0.0025 to 0.0046). However, this value currently is based on only a few well characterized microbes reproducing within a narrow ra...

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

authors： Grogan DW,Carver GT,Drake JW

更新日期：2001-07-03 00:00:00

abstract：:A gamma-trace variant protein is the major constituent of the amyloid fibrils in patients from Iceland with hereditary cerebral hemorrhage with amyloidosis. The protein consists of 110 residues and is similar to human urinary gamma-trace basic protein (or cystatin C) beginning at its 11th amino-terminal residue. It ha...

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

authors： Ghiso J,Jensson O,Frangione B

更新日期：1986-05-01 00:00:00

abstract：:Societies are complex systems, which tend to polarize into subgroups of individuals with dramatically opposite perspectives. This phenomenon is reflected-and often amplified-in online social networks, where, however, humans are no longer the only players and coexist alongside with social bots-that is, software-control...

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

authors： Stella M,Ferrara E,De Domenico M

更新日期：2018-12-04 00:00:00

abstract：:Current evidence favors the theory that, when the globular motor domain of myosin attaches to actin, the light chain binding domain or "lever arm" rotates, and thereby generates movement of actin filaments. Myosin is uniquely designed for such a role in that a long alpha-helix (approximately 9 nm) extending from the C...

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

authors： Sherwood JJ,Waller GS,Warshaw DM,Lowey S

更新日期：2004-07-27 00:00:00

abstract：:The values of the moment of inertia of the ground-state band of (168)Hf from J = 0(+) to 22(+) are interpreted as involving a revolving cluster with composition increasing steadily from p(10.5)n(14) to p(20.5)n(24), with radius of revolution 6.390 fm. The excited bands from 14(+) to 34(+), 21(-) to 33(-), and 18(-) to...

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

authors： Pauling L

更新日期：1984-05-01 00:00:00

abstract：:Determining trend and implementing detrending operations are important steps in data analysis. Yet there is no precise definition of "trend" nor any logical algorithm for extracting it. As a result, various ad hoc extrinsic methods have been used to determine trend and to facilitate a detrending operation. In this art...

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

authors： Wu Z,Huang NE,Long SR,Peng CK

更新日期：2007-09-18 00:00:00

abstract：:In animals, successful production of the visual chromophore (11-cis-retinal or derivatives thereof such as 11-cis-3-hydroxy-retinal) is essential for photoreceptor cell function and survival. These carotenoid-derived compounds must combine with a protein moiety (the opsin) to establish functional visual pigments. Evid...

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

authors： Oberhauser V,Voolstra O,Bangert A,von Lintig J,Vogt K

更新日期：2008-12-02 00:00:00

abstract：:There exist a limited but growing number of biological metal centers whose properties lie conspicuously outside the realm of known inorganic chemistry. The synthetic analogue approach, broadly directed, offers a powerful exploratory tool that can define intrinsic chemical possibilities for these sites while simultaneo...

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

authors： Lee SC,Holm RH

更新日期：2003-04-01 00:00:00

abstract：:Recent studies show that plant organ positioning may be mediated by localized concentrations of the plant hormone auxin. Auxin patterning in the shoot apical meristem is in turn brought about by the subcellular polar distribution of the putative auxin efflux mediator, PIN1. However, the question of what signals determ...

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

authors： Jönsson H,Heisler MG,Shapiro BE,Meyerowitz EM,Mjolsness E

更新日期：2006-01-31 00:00:00

abstract：:To coordinate movements with events in a dynamic environment the brain has to anticipate when those events occur. A classic example is the estimation of time to contact (TTC), that is, when an object reaches a target. It is thought that TTC is estimated from kinematic variables. For example, a tennis player might use ...

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

authors： Chang CJ,Jazayeri M

更新日期：2018-03-20 00:00:00