A simple generative model of collective online behavior.

abstract：:Reactive oxygen species (ROS) are well-known accelerants of aging, but, paradoxically, we show that physiological levels of ROS extend life span in pupae of the moth Helicoverpa armigera, resulting in the dormant state of diapause. This developmental switch appears to operate through a variant of the conventional insu...

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

authors： Zhang XS,Wang T,Lin XW,Denlinger DL,Xu WH

更新日期：2017-09-12 00:00:00

abstract：:In the rhesus monkey (Macaca mulatta), the frequency of pulsatile gonadotropic hormone release is relatively constant in the face of widely varying levels of estradiol (E2) in the peripheral circulation--e.g., in the course of the follicular phase of the menstrual cycle and after ovariectomy. This suggests that modula...

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

authors： Kesner JS,Wilson RC,Kaufman JM,Hotchkiss J,Chen Y,Yamamoto H,Pardo RR,Knobil E

更新日期：1987-12-01 00:00:00

abstract：:The multifunctional Ca2+/calmodulin-dependent protein kinase purified from rat brain cytosol undergoes an intramolecular self-phosphorylation or autophosphorylation. Autophosphorylation produces two strikingly different effects on kinase activity that are dependent on the level of ATP used in the reaction. At low but ...

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

authors： Lou LL,Lloyd SJ,Schulman H

更新日期：1986-12-01 00:00:00

abstract：:BALB/c mice immunized with myeloma proteins 315 or 460 made antibodies to the individually specific ("idiotypic") determinants of these proteins and suppressed growth of the corresponding transplanted tumor cells (MOPC-315 or MOPC-460). Stable, variant MOPC-315 tumors that produce only the light chain of protein 315 g...

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

authors： Lynch RG,Graff RJ,Sirisinha S,Simms ES,Eisen HN

更新日期：1972-06-01 00:00:00

abstract：:The interaction of configurations, including all possible singly excited configurations, is incorporated into the calculation of oscillatory and rotatory intensities of simple nonplanar pi-electronic systems such as skewed butadiene and acrolein. The results are discussed in terms of the reliability of the (self-consi...

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

authors： Cheong KK,Oshita A,Caldwell DJ,Eyring H

更新日期：1970-12-01 00:00:00

abstract：:The Millennium Ecosystem Assessment (MA) introduced a new framework for analyzing social-ecological systems that has had wide influence in the policy and scientific communities. Studies after the MA are taking up new challenges in the basic science needed to assess, project, and manage flows of ecosystem services and ...

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

authors： Carpenter SR,Mooney HA,Agard J,Capistrano D,Defries RS,Díaz S,Dietz T,Duraiappah AK,Oteng-Yeboah A,Pereira HM,Perrings C,Reid WV,Sarukhan J,Scholes RJ,Whyte A

更新日期：2009-02-03 00:00:00

abstract：:Although a number of studies have highlighted the importance of offline processes for memory, how these mechanisms influence future learning remains unknown. Participants with established memories for a set of initial face-object associations were scanned during passive rest and during encoding of new related and unre...

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

authors： Schlichting ML,Preston AR

更新日期：2014-11-04 00:00:00

abstract：:Insects have diversified through more than 450 million y of Earth's changeable climate, yet rapidly shifting patterns of temperature and precipitation now pose novel challenges as they combine with decades of other anthropogenic stressors including the conversion and degradation of land. Here, we consider how insects ...

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

authors： Halsch CA,Shapiro AM,Fordyce JA,Nice CC,Thorne JH,Waetjen DP,Forister ML

更新日期：2021-01-12 00:00:00

abstract：:The cytoplasm and biomembranes in biological cells contain large numbers of proteins that cyclically change their shapes. They are molecular machines that can function as molecular motors or carry out various other tasks in the cell. Many enzymes also undergo conformational changes within their turnover cycles. We ana...

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

authors： Mikhailov AS,Kapral R

更新日期：2015-07-14 00:00:00

abstract：:One of the advantages of the production of monoclonal antibodies by tissue culture methods is that they can be internally labeled by using appropriate radioactive amino acid in the culture fluid. Thus, radioactive immunological probes of high specific activity can be prepared. Here we report applications of these inte...

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

authors： Cuello AC,Priestley JV,Milstein C

更新日期：1982-01-01 00:00:00

abstract：:The F-box protein Skp2 (S-phase kinase-associated protein 2) positively regulates the G(1)-S transition by controlling the stability of several G(1) regulators, such as the cell cycle inhibitor p27. We show here that Skp2 expression correlates directly with grade of malignancy and inversely with p27 levels in human ly...

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

authors： Latres E,Chiarle R,Schulman BA,Pavletich NP,Pellicer A,Inghirami G,Pagano M

更新日期：2001-02-27 00:00:00

abstract：:In Escherichia coli, acetyl phosphate can be formed from acetyl-CoA via the phosphotransacetylase (phosphate acetyltransferase; acetyl-CoA:orthophosphate acetyltransferase, EC 2.3.1.8) reaction and from acetate (plus ATP) via the acetate kinase (ATP:acetate phosphotransferase, EC 2.7.2.1) reaction. By restricting acet...

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

authors： Hong JS,Hunt AG,Masters PS,Lieberman MA

更新日期：1979-03-01 00:00:00

abstract：:Type IV pili (Tfp), which are key virulence factors in many bacterial pathogens, define a large group of multipurpose filamentous nanomachines widespread in Bacteria and Archaea. Tfp biogenesis is a complex multistep process, which relies on macromolecular assemblies composed of 15 conserved proteins in model gram-neg...

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

authors： Goosens VJ,Busch A,Georgiadou M,Castagnini M,Forest KT,Waksman G,Pelicic V

更新日期：2017-06-20 00:00:00

abstract：:Dolichol phosphate mannose (Dol-P-Man), formed upon transfer of Man from GDPMan to Dol-P, is a mannosyl donor in pathways leading to N-glycosylation, glycosyl phosphatidylinositol membrane anchoring, and O-mannosylation of protein. Dol-P-Man synthase is an essential protein in Saccharomyces cerevisiae. We have cloned ...

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

authors： Colussi PA,Taron CH,Mack JC,Orlean P

更新日期：1997-07-22 00:00:00

abstract：:Humans assess the credibility of information gained from others on a daily basis; this ongoing assessment is especially crucial for avoiding exploitation by others. We used a repeated, two-person bargaining game and a cognitive hierarchy model to test how subjects judge the information sent asymmetrically from one pla...

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

authors： Bhatt MA,Lohrenz T,Camerer CF,Montague PR

更新日期：2012-05-29 00:00:00

abstract：:The plasmid construct pSVO-CAT has been used to test adenovirus promoter activities in the unmethylated or methylated state. We have now observed that the E2A late promoter of adenovirus type 2 (Ad2) DNA also activated the chloramphenicol acetyltransferase (CAT) gene upon transfection of the pAd2E2A-CAT construct into...

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

authors： Langner KD,Weyer U,Doerfler W

更新日期：1986-03-01 00:00:00

abstract：:Delta5 and Delta6 fatty acid desaturases are critical enzymes in the pathways for the biosynthesis of the polyunsaturated fatty acids arachidonic, eicosapentaenoic, and docosahexaenoic acids. They are encoded by distinct genes in mammals and Caenorhabditis elegans. This paper describes a cDNA isolated from zebrafish (...

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

authors： Hastings N,Agaba M,Tocher DR,Leaver MJ,Dick JR,Sargent JR,Teale AJ

更新日期：2001-12-04 00:00:00

abstract：:CD83 is commonly known as a specific marker for mature dendritic cells. It has been shown to be important for CD4(+) T-cell development in the thymus. However, its function in the peripheral immune system remains enigmatic. Here, we show that CD83 inhibits proliferation and production of IL-2 and IFN-γ by T cells, and...

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

authors： Chen L,Zhu Y,Zhang G,Gao C,Zhong W,Zhang X

更新日期：2011-11-15 00:00:00

abstract：:The exo isomer of aflatoxin B1 (AFB1) 8,9-epoxide appears to be the only product of AFB1 involved in reaction with DNA and reacts with the N7 atom of guanine via an SN2 reaction from an intercalated state. Although the epoxide hydrolyzes rapidly in H2O (0.6 s-1 at 25 degrees C), very high yields of DNA adduct result. ...

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

authors： Johnson WW,Guengerich FP

更新日期：1997-06-10 00:00:00

abstract：:An invariant substructure that forms two interlocked pairs of neighboring beta-strands occurs in essentially all known sandwich-like proteins. Eight conserved positions in these strands were recently shown to act as structural determinants. To test whether the residues at these invariant positions are conserved for me...

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

authors： Wilson CJ,Wittung-Stafshede P

更新日期：2005-03-15 00:00:00

abstract：:To study C(0)a priori estimates for solutions to certain complex Monge-Ampère equations, I introduce a coherent sheaf of ideals and show that it satisfies various global algebrogeometric conditions, including a cohomology vanishing theorem. This technique is used to establish the existence of Kähler-Einstein metrics o...

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

authors： Nadel AM

更新日期：1989-10-01 00:00:00

abstract：:DNA polymerases from Xenopus laevis oocytes, unfertilized eggs, and kidney cells grown in culture have been characterized. The same three major DNA polymerase activities are present in all cell types examined. We attempt to relate the characteristics of amphibian enzymes to those of mammalian polymerases. ...

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

authors： Tatò F,Gandini DA,Tocchini-Valentini GP

更新日期：1974-09-01 00:00:00

abstract：:Small noncoding microRNAs (miRNAs) can contribute to cancer development and progression and are differentially expressed in normal tissues and cancers. From a large-scale miRnome analysis on 540 samples including lung, breast, stomach, prostate, colon, and pancreatic tumors, we identified a solid cancer miRNA signatur...

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

authors： Volinia S,Calin GA,Liu CG,Ambs S,Cimmino A,Petrocca F,Visone R,Iorio M,Roldo C,Ferracin M,Prueitt RL,Yanaihara N,Lanza G,Scarpa A,Vecchione A,Negrini M,Harris CC,Croce CM

更新日期：2006-02-14 00:00:00

abstract：:Renal cell carcinoma (RCC) and normal kidney tissues have been examined from 34 patients with sporadic, nonhereditary RCC. Eighteen of the 21 cytogenetically examined tumors (86%) had a detectable anomaly of chromosome arm 3p distal to band 3p11.2-p13, manifested as a deletion, combined with the nonreciprocal transloc...

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

authors： Kovacs G,Erlandsson R,Boldog F,Ingvarsson S,Müller-Brechlin R,Klein G,Sümegi J

更新日期：1988-03-01 00:00:00

abstract：:The heavy chains of both botulinum neurotoxin type B and tetanus toxin form channels in planar bilayer membranes. These channels have pH-dependent and voltage-dependent properties that are remarkably similar to those previously described for diphtheria toxin. Selectivity experiments with anions and cations show that t...

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

authors： Hoch DH,Romero-Mira M,Ehrlich BE,Finkelstein A,DasGupta BR,Simpson LL

更新日期：1985-03-01 00:00:00

abstract：:PKC eta is expressed predominantly in the epithelial tissues; however, its role in the regulation of epithelial tight junctions (TJs) is unknown. We present evidence that PKC eta phosphorylates occludin on threonine residues (T403 and T404) and plays a crucial role in the assembly and/or maintenance of TJs in Caco-2 a...

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

authors： Suzuki T,Elias BC,Seth A,Shen L,Turner JR,Giorgianni F,Desiderio D,Guntaka R,Rao R

更新日期：2009-01-06 00:00:00

abstract：:Mutagenesis of protein-encoding sequences occurs ubiquitously; it enables evolution, accumulates during aging, and is associated with disease. Many biotechnological methods exploit random mutations to evolve novel proteins. To quantitate protein tolerance to random change, it is vital to understand the probability tha...

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

authors： Guo HH,Choe J,Loeb LA

更新日期：2004-06-22 00:00:00

abstract：:Degradation of the most abundant membrane protein on earth, the light-harvesting complex of Photosystem II (LHC II), is highly regulated under various environmental conditions, e.g., light stress, to prevent photochemical damage to the reaction center. We identified the LHC II degrading protease in Arabidopsis thalian...

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

authors： Zelisko A,García-Lorenzo M,Jackowski G,Jansson S,Funk C

更新日期：2005-09-20 00:00:00

abstract：:Human embryonic stem cells have the potential to differentiate into various cell types and, thus, may be useful as a source of cells for transplantation or tissue engineering. We describe here the differentiation steps of human embryonic stem cells into endothelial cells forming vascular-like structures. The human emb...

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

authors： Levenberg S,Golub JS,Amit M,Itskovitz-Eldor J,Langer R

更新日期：2002-04-02 00:00:00

abstract：:Variation of chloroplast DNA and nuclear ribosomal DNA (DNA encoding ribosomal RNA) was studied for five species of white oak native to the eastern United States. Although these species differ in many morphological characters and have different (though overlapping) geographical ranges and ecological tolerances, they a...

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

authors： Whittemore AT,Schaal BA

更新日期：1991-03-15 00:00:00