Dielectric constant of atomic fluids with variable polarizability.

abstract：:We combine eight previously proposed measures to construct an index of political polarization among US adults. We find that polarization has increased the most among the demographic groups least likely to use the Internet and social media. Our overall index and all but one of the individual measures show greater incre...

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

authors： Boxell L,Gentzkow M,Shapiro JM

更新日期：2017-10-03 00:00:00

abstract：:Under a stretching force, the sugar ring of polysaccharide molecules switches from the chair to the boat-like or inverted chair conformation. This conformational change can be observed by stretching single polysaccharide molecules with an atomic force microscope. In those early experiments, the molecules were stretche...

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

authors： Marszalek PE,Li H,Oberhauser AF,Fernandez JM

更新日期：2002-04-02 00:00:00

abstract：:Deletion of 13 amino acids from the carboxyl terminus of the 149-amino acid staphylococcal nuclease molecule results in a denatured, partly unfolded molecule that lacks persistent secondary structure but is compact under physiological conditions. Since the modification is a carboxyl-terminal deletion, it is argued tha...

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

authors： Flanagan JM,Kataoka M,Shortle D,Engelman DM

更新日期：1992-01-15 00:00:00

abstract：:A common complaint among pain patients is that they lose their appetite. These accounts are anecdotal, however, and the neural mechanism underlying pain-induced loss of appetite remains unknown. In this study, we documented the occurrence of appetite loss in patients under migraine attack and investigated the neuronal...

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

authors： Malick A,Jakubowski M,Elmquist JK,Saper CB,Burstein R

更新日期：2001-08-14 00:00:00

abstract：:Xenopus laevis tadpole tails contain fast muscle fibers oriented in chevrons and two pairs of slow muscle "cords" along the length of the tail. When tail resorption is inhibited by a number of different treatments, fast muscle but not the slow cord muscle still is lost, demonstrating that the fast tail muscle is a dir...

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

authors： Das B,Schreiber AM,Huang H,Brown DD

更新日期：2002-09-17 00:00:00

abstract：:The outcome of exposure to infectious microbes or their toxins is influenced by both microbial and host genes. Some host genes encode defense mechanisms, whereas others assist pathogen functions. Genomic analyses have associated host gene mutations with altered infectious disease susceptibility, but evidence for causa...

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

authors： Martchenko M,Candille SI,Tang H,Cohen SN

更新日期：2012-02-21 00:00:00

abstract：:A theoretical description of aqueous hydration in the minor groove of a B-form DNA is presented on the basis of a liquid-state Monte Carlo computer simulation on a system consisting of the oligonucleotide duplex d(CGCGAATTCGCG).d(GCGCTTAAGCGC) in a canonical B-form together with 1777 water molecules contained in a hex...

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

authors： Subramanian PS,Ravishanker G,Beveridge DL

更新日期：1988-03-01 00:00:00

abstract：:Chondrules may have played a critical role in the earliest stages of planet formation by mediating the accumulation of dust into planetesimals. However, the origin of chondrules and their significance for planetesimal accretion remain enigmatic. Here, we show that chondrules and matrix in the carbonaceous chondrite Al...

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

authors： Budde G,Kleine T,Kruijer TS,Burkhardt C,Metzler K

更新日期：2016-03-15 00:00:00

abstract：:A way to assess specific CD8+ T-cell activity in a skin test analogous to the conventional delayed-type hypersensitivity (DTH) reaction for CD4+ T cells is presented. Local injection of viral class I binding peptides caused a specific CD8+ T-cell-mediated DTH in footpads of virally infected mice. The DTH was inducible...

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

authors： Kündig TM,Althage A,Hengartner H,Zinkernagel RM

更新日期：1992-08-15 00:00:00

abstract：:Rapid antibody production in response to invading pathogens requires the dramatic expansion of pathogen-derived antigen-specific B lymphocyte populations. Whether B cell population dynamics are based on stochastic competition between competing cell fates, as in the development of competence by the bacterium Bacillus s...

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

authors： Mitchell S,Roy K,Zangle TA,Hoffmann A

更新日期：2018-03-20 00:00:00

abstract：:Although gamma/delta T cells express numerous in vitro functions similar to alpha/beta T cells, little is known about their biological functioning in vivo. Furthermore, it is unclear whether alpha/beta T cells and gamma/delta T cells act independently or in a coordinated way. In the present study, gamma/delta T cells ...

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

authors： Kaufmann SH,Blum C,Yamamoto S

更新日期：1993-10-15 00:00:00

abstract：:Although many types of ancient bacteria and archea rely on hydrogen sulfide (H(2)S) for their energy production, eukaryotes generate ATP in an oxygen-dependent fashion. We hypothesize that endogenous H(2)S remains a regulator of energy production in mammalian cells under stress conditions, which enables the body to co...

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

authors： Fu M,Zhang W,Wu L,Yang G,Li H,Wang R

更新日期：2012-02-21 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：:In all photosynthetic organisms, light energy is used to drive electrons from a donor chlorophyll species via a series of acceptors across a biological membrane. These light-induced electron-transfer processes display a remarkably high quantum efficiency, indicating a near-complete inhibition of unproductive charge re...

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

authors： Makita H,Hastings G

更新日期：2017-08-29 00:00:00

abstract：:Translocations involving c-myc and an Ig locus have been reported rarely in human multiple myeloma (MM). Using specific fluorescence in situ hybridization probes, we show complex karyotypic abnormalities of the c-myc or L-myc locus in 19 of 20 MM cell lines and approximately 50% of advanced primary MM tumors. These ab...

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

authors： Shou Y,Martelli ML,Gabrea A,Qi Y,Brents LA,Roschke A,Dewald G,Kirsch IR,Bergsagel PL,Kuehl WM

更新日期：2000-01-04 00:00:00

abstract：:Transarterial chemoembolization (TACE) is the main treatment for intermediate stage hepatocellular carcinoma (HCC) with Barcelona Clinic Liver Cancer classification because of its exclusive arterial blood supply. Although TACE achieves substantial necrosis of the tumor, complete tumor necrosis is uncommon, and the res...

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

authors： Lin WH,Yeh SH,Yeh KH,Chen KW,Cheng YW,Su TH,Jao P,Ni LC,Chen PJ,Chen DS

更新日期：2016-10-18 00:00:00

abstract：:Measurements of the effect of DNA on rates of bimolecular energy transfer between ions provide a direct indication of how cations cluster in regions near DNA and how anions are repelled from the same regions. Energy transfer from luminescent lanthanide ions (in the "rapid-diffusion" limit) probes collision frequencies...

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

authors： Wensel TG,Meares CF,Vlachy V,Matthew JB

更新日期：1986-05-01 00:00:00

abstract：:We present whole-genome assemblies of four divergent Arabidopsis thaliana strains that complement the 125-Mb reference genome sequence released a decade ago. Using a newly developed reference-guided approach, we assembled large contigs from 9 to 42 Gb of Illumina short-read data from the Landsberg erecta (Ler-1), C24,...

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

authors： Schneeberger K,Ossowski S,Ott F,Klein JD,Wang X,Lanz C,Smith LM,Cao J,Fitz J,Warthmann N,Henz SR,Huson DH,Weigel D

更新日期：2011-06-21 00:00:00

abstract：:Molecular genetic analyses of the young pseudogenes of the immunoglobulin C epsilon genes were carried out to obtain qualitative evidence for the phylogenetic branching pattern of hominoid primates. We found that Old World monkeys had two C epsilon genes, one of which was processed. Among the hominoids examined only t...

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

authors： Ueda S,Takenaka O,Honjo T

更新日期：1985-06-01 00:00:00

abstract：:The genes encoding the variable (V) region of the B-cell antigen receptor (BCR) are assembled from V, D (diversity), and J (joining) elements through a RAG-mediated recombination process that relies on the recognition of recombination signal sequences (RSSs) flanking the individual elements. Secondary V(D)J rearrangem...

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

authors： Sun A,Novobrantseva TI,Coffre M,Hewitt SL,Jensen K,Skok JA,Rajewsky K,Koralov SB

更新日期：2015-02-03 00:00:00

abstract：:A central event in the eukaryotic cell cycle is the decision to commence DNA replication (S phase). Strict controls normally operate to prevent repeated rounds of DNA replication without intervening mitoses ("endoreplication") or initiation of mitosis before DNA is fully replicated ("mitotic catastrophe"). Some of the...

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

authors： Novak B,Tyson JJ

更新日期：1997-08-19 00:00:00

abstract：:During reverse transcription of retroviral RNA, synthesis of (-) strand DNA is primed by a cellular tRNA that anneals to an 18-nt primer binding site within the 5' long terminal repeat. For (+) strand synthesis using a (-) strand DNA template linked to the tRNA primer, only the first 18 nt of tRNA are replicated to re...

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

authors： Burnett BP,McHenry CS

更新日期：1997-07-08 00:00:00

abstract：:After males of Lasioglossum zephyrum (Hymenoptera: Halictidae) have first been exposed to a conspecific female, the attractiveness of a second female diminishes with increasing genealogical relationship between the two females. The most parsimonious explanation for this is a polygenically controlled female sex pheromo...

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

authors： Smith BH

更新日期：1983-07-01 00:00:00

abstract：:Extensive terahertz laser vibration-rotation-tunneling spectra and mid-IR laser spectra have been compiled for several isotopomers of small (dimer through hexamer) water clusters. These data, in conjunction with new theoretical advances, quantify the structures, force fields, dipole moments, and hydrogen bond rearrang...

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

authors： Keutsch FN,Saykally RJ

更新日期：2001-09-11 00:00:00

abstract：:The receptor for granulocyte-macrophage colony-stimulating factor (GM-CSF) is composed of an alpha and beta subunit, which together form the high-affinity receptor. The alpha subunit by itself binds ligand at low affinity, whereas the isolated beta subunit does not bind GM-CSF. It is generally believed that the high-a...

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

authors： Ding DX,Rivas CI,Heaney ML,Raines MA,Vera JC,Golde DW

更新日期：1994-03-29 00:00:00

abstract：:Tephritid fruit flies belonging to the Rhagoletis pomonella sibling species complex are controversial because they have been proposed to diverge in sympatry (in the absence of geographic isolation) by shifting and adapting to new host plants. Here, we report evidence suggesting a surprising source of genetic variation...

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

authors： Feder JL,Berlocher SH,Roethele JB,Dambroski H,Smith JJ,Perry WL,Gavrilovic V,Filchak KE,Rull J,Aluja M

更新日期：2003-09-02 00:00:00

abstract：:Intracellular proteolytic processing of precursor polypeptides is an essential step in the maturation of many proteins, including plasma proteins, hormones, neuropeptides, and growth factors. Most frequently, propeptide cleavage occurs after paired basic amino acid residues. To date, no mammalian propeptide processing...

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

authors： Wise RJ,Barr PJ,Wong PA,Kiefer MC,Brake AJ,Kaufman RJ

更新日期：1990-12-01 00:00:00

abstract：:We and others have reported that the vast majority of virus-producing CD4(+) T cells during the acute infection of rhesus macaques with simian immunodeficiency virus (SIV) or CXCR4 (X4)-using simian/human immunodeficiency viruses (SHIVs) exhibited a nonactivated phenotype. These findings have been extended to show tha...

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

authors： Nishimura Y,Sadjadpour R,Mattapallil JJ,Igarashi T,Lee W,Buckler-White A,Roederer M,Chun TW,Martin MA

更新日期：2009-05-12 00:00:00

abstract：:Pyruvate ferredoxin oxidoreductase (POR) has been previously purified from the hyperthermophilic archaeon, Pyrococcus furiosus, an organism that grows optimally at 100 degrees C by fermenting carbohydrates and peptides. The enzyme contains thiamine pyrophosphate and catalyzes the oxidative decarboxylation of pyruvate ...

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

authors： Ma K,Hutchins A,Sung SJ,Adams MW

更新日期：1997-09-02 00:00:00

abstract：:Branched polyethylenimine (PEI) chains with an average molecular mass of 2 kDa (PEI2) have been covalently attached to gold nanoparticles (GNPs), and the potency of the resulting PEI2-GNPs conjugates as vectors for the delivery of plasmid DNA into monkey kidney (COS-7) cells in the presence of serum in vitro has been ...

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

authors： Thomas M,Klibanov AM

更新日期：2003-08-05 00:00:00