Why we need to look beyond the glass transition temperature to characterize the dynamics of thin supported polymer films.

abstract：:Recent functional imaging studies have revealed coactivation in a distributed network of cortical regions that characterizes the resting state, or default mode, of the human brain. Among the brain regions implicated in this network, several, including the posterior cingulate cortex and inferior parietal lobes, have al...

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

authors： Greicius MD,Srivastava G,Reiss AL,Menon V

更新日期：2004-03-30 00:00:00

abstract：:We have found a soluble cyclase, using for assay radioactively marked ATP as precursor. The reaction product was isolated by thin-layer chromatography and identified by specific degradation. After homogenization, part of the activity remained in the particulate fraction but could be easily extracted. The cyclase was c...

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

authors： Tao M,Lipmann F

更新日期：1969-05-01 00:00:00

abstract：:We present the first part of a quantitative theory for the structure and dynamics of forests at demographic and resource steady state. The theory uses allometric scaling relations, based on metabolism and biomechanics, to quantify how trees use resources, fill space, and grow. These individual-level traits and propert...

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

authors： West GB,Enquist BJ,Brown JH

更新日期：2009-04-28 00:00:00

abstract：:Establishing a timeline for the evolution of novelties is a common, unifying goal at the intersection of evolutionary and developmental biology. Analyses of gene regulatory networks (GRNs) provide the ability to understand the underlying genetic and developmental mechanisms responsible for the origin of morphological ...

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

authors： Thompson JR,Erkenbrack EM,Hinman VF,McCauley BS,Petsios E,Bottjer DJ

更新日期：2017-06-06 00:00:00

abstract：:Hydrogenases catalyze the reversible reaction 2H(+) + 2e(-) ↔ H(2) with an equilibrium constant that is dependent on the reducing potential of electrons carried by their redox partner. To examine the possibility of increasing the photobiological production of hydrogen within cyanobacterial cultures, we expressed the [...

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

authors： Ducat DC,Sachdeva G,Silver PA

更新日期：2011-03-08 00:00:00

abstract：:The molecular size and stability of the nerve growth factor (NGF) secreted in culture by L cells have been studied by sedimentation and gel filtration chromatography. Results indicate that L cell NGF has a molecular weight of 160,000. It contains as part of its structure a protein component that is biologically, immun...

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

authors： Pantazis NJ,Blanchard MH,Arnason BG,Young M

更新日期：1977-04-01 00:00:00

abstract：:This article emphasizes the role played by a remarkable pointwise inequality satisfied by fractionary derivatives in order to obtain maximum principles and Lp-decay of solutions of several interesting partial differential equations. In particular, there are applications to quasigeostrophic flows, in two space variable...

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

authors： Cordoba A,Cordoba D

更新日期：2003-12-23 00:00:00

abstract：:Whereas the laws of thermodynamics prohibit extraction of useful work from the Brownian motion of particles in equilibrium, these motions can be "rectified" under nonequilibrium conditions, for example, in the presence of asymmetric geometrical obstacles. Here, we describe a class of systems in which aerobic bacteria ...

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

authors： Sokolov A,Apodaca MM,Grzybowski BA,Aranson IS

更新日期：2010-01-19 00:00:00

abstract：:Human diploid fibroblasts (HDFs) possess Ca(2+)-dependent membrane currents. These currents were suppressed in late-passage normal (senescent) HDFs and prematurely senescent HDFs derived from a subject with Werner syndrome (WS), compared with early-passage normal (young) HDFs. When young HDFs were microinjected with m...

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

authors： Liu S,Thweatt R,Lumpkin CK Jr,Goldstein S

更新日期：1994-03-15 00:00:00

abstract：:A descriptive medium for the presentation of protein structure has been developed and used to evaluate the structure of the active site of bovine trypsin (EC 3.4.21.4). This technique, involving advanced computer graphics technology, permits the facile display of a representation of the molecular surface of proteins o...

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

authors： Feldmann RJ,Bing DH,Furie BC,Furie B

更新日期：1978-11-01 00:00:00

abstract：:Topological mechanical metamaterials are artificial structures whose unusual properties are protected very much like their electronic and optical counterparts. Here, we present an experimental and theoretical study of an active metamaterial--composed of coupled gyroscopes on a lattice--that breaks time-reversal symmet...

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

authors： Nash LM,Kleckner D,Read A,Vitelli V,Turner AM,Irvine WT

更新日期：2015-11-24 00:00:00

abstract：:DEAD-box RNA helicase proteins use the energy of ATP hydrolysis to drive the unwinding of duplex RNA. However, the mechanism that couples ATP utilization to duplex RNA unwinding is unknown. We measured ATP utilization and duplex RNA unwinding by DbpA, a non-processive bacterial DEAD-box RNA helicase specifically activ...

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

authors： Henn A,Cao W,Licciardello N,Heitkamp SE,Hackney DD,De La Cruz EM

更新日期：2010-03-02 00:00:00

abstract：:Carbon fixation is the process by which CO(2) is incorporated into organic compounds. In modern agriculture in which water, light, and nutrients can be abundant, carbon fixation could become a significant growth-limiting factor. Hence, increasing the fixation rate is of major importance in the road toward sustainabili...

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

authors： Bar-Even A,Noor E,Lewis NE,Milo R

更新日期：2010-05-11 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：:A glycoprotein was isolated and purified to homogeneity from the serum of a patient with chronic non-A, non-B hepatitis. NaDodSO4/PAGE of the glycoprotein revealed a single major band at Mr approximately 77,000. Antibodies to this glycoprotein were shown to possess the following immunoreactivity: (i) they reacted by r...

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

authors： Seto B,Gerety RJ

更新日期：1985-08-01 00:00:00

abstract：:The structure of DNA toroids made of individual DNA molecules of various lengths (3,000 to 55,000 bp) was studied, by using partially filled bacteriophage capsids in conjunction with cryoelectron microscopy. The tetravalent cation spermine was diffused through the capsid to condense the DNA under conditions that were ...

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

authors： Leforestier A,Livolant F

更新日期：2009-06-09 00:00:00

abstract：:The Drosophila kep1 gene encodes an RNA binding protein related to the murine QUAKING apoptotic inducer. We have previously shown that kep1 can induce apoptosis when transfected into different cell lines. To better define the role of Kep1 in apoptosis, we generated kep1 null flies. These flies were viable, but females...

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

authors： Di Fruscio M,Styhler S,Wikholm E,Boulanger MC,Lasko P,Richard S

更新日期：2003-02-18 00:00:00

abstract：:Efficient and reliable classification of visual stimuli requires that their representations reside a low-dimensional and, therefore, computationally manageable feature space. We investigated the ability of the human visual system to derive such representations from the sensory input-a highly nontrivial task, given the...

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

authors： Cutzu F,Edelman S

更新日期：1996-10-15 00:00:00

abstract：:To generate antibodies with different effector functions, B cells undergo Immunoglobulin Heavy Chain (IgH) class switch recombination (CSR). The ligation step of CSR is usually mediated by the classical nonhomologous end-joining (cNHEJ) pathway. In cNHEJ-deficient cells, a remarkable ∼25% of CSR can be achieved by the...

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

authors： Wang XS,Zhao J,Wu-Baer F,Shao Z,Lee BJ,Cupo OM,Rabadan R,Gautier J,Baer R,Zha S

更新日期：2020-10-13 00:00:00

abstract：:The binned distribution densities of magnitudes in both the complete and the declustered catalogs of earthquakes in the Southern California region have two significantly different branches with crossover magnitude near M = 4.8. In the case of declustered earthquakes, the b-values on the two branches differ significant...

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

authors： Knopoff L

更新日期：2000-10-24 00:00:00

abstract：:We review a program of research that uses neuroimaging techniques to determine the functional and neural architecture of human working memory. A first set of studies indicates that verbal working memory includes a storage component, which is implemented neurally by areas in the left-hemisphere posterior parietal corte...

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

authors： Smith EE,Jonides J

更新日期：1998-09-29 00:00:00

abstract：:Histone deacetylase inhibitors (HDACi) represent a new group of drugs currently being tested in a wide variety of clinical applications. They are especially effective in preclinical models of cancer where they show antiproliferative action in many different types of cancer cells. Recently, the first HDACi was approved...

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

authors： Haberland M,Johnson A,Mokalled MH,Montgomery RL,Olson EN

更新日期：2009-05-12 00:00:00

abstract：:The history of the genus Pan is a topic of enduring interest. Chimpanzees (Pan troglodytes) are often divided into subspecies, but the population structure and genetic history of chimpanzees across Africa remain unclear. Some population genetics studies have led to speculation that, until recently, this species consti...

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

authors： Gonder MK,Locatelli S,Ghobrial L,Mitchell MW,Kujawski JT,Lankester FJ,Stewart CB,Tishkoff SA

更新日期：2011-03-22 00:00:00

abstract：:The ability to integrate visual information over space is a fundamental component of human pattern vision. Regardless of whether it is for detecting luminance contrast or for recognizing objects in a cluttered scene, the position of the target in the visual field governs the size of a window within which visual inform...

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

authors： Kwon M,Liu R

更新日期：2019-02-26 00:00:00

abstract：:Purified dicyclohexylcarbodiimide-sensitive ATPase (TF0-F1) from thermophilic bacterium PS3 is composed of a water soluble part with ATP hydrolytic activity (TF1) and a water insoluble moiety (TF0). All of the five subunits (alpha, beta, gamma, delta, and epsilon) of TF1 were isolated. TF1 was reconstituted from the f...

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

authors： Yoshida M,Okamoto H,Sone N,Hirata H,Kagawa Y

更新日期：1977-03-01 00:00:00

abstract：:We introduce a model of evolution in which competing organisms are represented by percolation lattice models. Fitness is based on the number of occupied sites remaining after removing a cluster connected to a randomly selected site. High-fitness individuals arising through mutation and selection must trade off density...

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

authors： Zhou T,Carlson JM,Doyle J

更新日期：2002-02-19 00:00:00

abstract：:All science has uncertainty. Unless that uncertainty is communicated effectively, decision makers may put too much or too little faith in it. The information that needs to be communicated depends on the decisions that people face. Are they (i) looking for a signal (e.g., whether to evacuate before a hurricane), (ii) c...

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

authors： Fischhoff B,Davis AL

更新日期：2014-09-16 00:00:00

abstract：:The Drake Passage (DP) is the major geographic constriction for the Antarctic Circumpolar Current (ACC) and exerts a strong control on the exchange of physical, chemical, and biological properties between the Atlantic, Pacific, and Indian Ocean basins. Resolving changes in the flow of circumpolar water masses through ...

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

authors： Lamy F,Arz HW,Kilian R,Lange CB,Lembke-Jene L,Wengler M,Kaiser J,Baeza-Urrea O,Hall IR,Harada N,Tiedemann R

更新日期：2015-11-03 00:00:00

abstract：:A method is described for monitoring the enzyme-mediated unwinding of duplex DNA spectrophotometrically. The assay employs a partially duplex oligonucleotide substrate modified at the complementary end with coumarin and fluorescein moieties. When in close proximity the fluorescein quenches the fluorescence of coumarin...

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

authors： Houston P,Kodadek T

更新日期：1994-06-07 00:00:00

abstract：:The TFIID transcription initiation complex is composed of TBP and multiple TAFs. Studies in unicellular systems indicate that TAF250 is required for progression through G(1)/S of the cell cycle and repression of apoptosis. Here we extend these in vivo studies by determining the developmental requirements for TAF250 in...

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

authors： Wassarman DA,Aoyagi N,Pile LA,Schlag EM

更新日期：2000-02-01 00:00:00