Combining natural language processing and network analysis to examine how advocacy organizations stimulate conversation on social media.

abstract：:At the synapse, presynaptic membranes specialized for vesicular traffic are linked to postsynaptic membranes specialized for signal transduction. The mechanisms that connect pre- and postsynaptic membranes into synaptic junctions are unknown. Neuroligins and beta-neurexins are neuronal cell-surface proteins that bind ...

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

authors： Song JY,Ichtchenko K,Südhof TC,Brose N

更新日期：1999-02-02 00:00:00

abstract：:Assembly of nitrogenase FeMoco is one of the key processes in bioinorganic chemistry. NifB and NifEN are two essential elements immediately adjacent to each other along the biosynthetic pathway of FeMoco. Previously, an 8Fe-precursor of FeMoco was identified on NifEN; however, the identity of the biosynthetic intermed...

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

authors： Wiig JA,Hu Y,Ribbe MW

更新日期：2011-05-24 00:00:00

abstract：:An artificial charge pair buried in the hydrophobic core of staphylococcal nuclease was engineered by making the V23E and L36K substitutions. Buried individually, Glu-23 and Lys-36 both titrate with pKa values near 7. When buried together their pKa values appear to be normal. The ionizable moieties of the buried Glu-L...

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

authors： Robinson AC,Castañeda CA,Schlessman JL,García-Moreno EB

更新日期：2014-08-12 00:00:00

abstract：:Somatic mutation and neoplastic transformation of diploid Syrian hamster embryo cells were examined concomitantly. Mutations induced by benzo[a]pyrene and N-methyl-N'-nitro-N-nitrosoguanidine were quantitated at the hypoxanthine phosphoribosyltransferase and Na(+)/K(+) ATPase loci and compared to phenotypic transforma...

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

authors： Barrett JC,Ts'o PO

更新日期：1978-07-01 00:00:00

abstract：:Staphylococcus aureus surface protein SasG promotes cell-cell adhesion during the accumulation phase of biofilm formation, but the molecular basis of this interaction remains poorly understood. Here, we unravel the mechanical properties of SasG on the surface of living bacteria, that is, in its native cellular environ...

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

authors： Formosa-Dague C,Speziale P,Foster TJ,Geoghegan JA,Dufrêne YF

更新日期：2016-01-12 00:00:00

abstract：:Many cortical neurons combine the information ascending and descending the cortical hierarchy. In the classical view, this information is combined nonlinearly to give rise to a single firing-rate output, which collapses all input streams into one. We analyze the extent to which neurons can simultaneously represent mul...

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

authors： Naud R,Sprekeler H

更新日期：2018-07-03 00:00:00

abstract：:A molecular dynamics simulation of the gramicidin A channel in an explicit dimyristoyl phosphatidylcholine bilayer was generated to study the details of lipid-protein interactions at the microscopic level. Solid-state NMR properties of the channel averaged over the 500-psec trajectory are in excellent agreement with a...

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

authors： Woolf TB,Roux B

更新日期：1994-11-22 00:00:00

abstract：:The regional structure of fibrinogen was considered in reference to the terminal plasmin-cleavage fragments, D and E. By two independent approaches, a yield of two D and two E fragments was determined and this established the presence of two D and two E regions in each fibrinogen molecule. Immunochemically, it was sho...

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

authors： Plow EF,Edgington TS

更新日期：1974-01-01 00:00:00

abstract：:The proton markers located in the minor groove of the d(C-G-C-G-A-A-T-T-C-G-C-G) duplex and its netropsin complex have been assigned from measurements of intramolecular nuclear Overhauser effects (NOEs) between exchangeable imino protons and nonexchangeable base protons on the same and adjacent base pairs. Several poi...

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

authors： Patel DJ

更新日期：1982-11-01 00:00:00

abstract：:The successful treatment of cancer by boron neutron-capture therapy (BNCT) requires the selective concentration of boron-10 within malignant tumors. The potential of liposomes to deliver boron-rich compounds to tumors has been assessed by the examination of the biodistribution of boron delivered by liposomes in tumor-...

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

authors： Shelly K,Feakes DA,Hawthorne MF,Schmidt PG,Krisch TA,Bauer WF

更新日期：1992-10-01 00:00:00

abstract：:A recombinant vaccinia virus that directs the synthesis of bacteriophage T7 RNA polymerase provides the basis for the expression of genes that are regulated by T7 promoters in mammalian cells. The T7 transcripts, which account for as much as 30% of the total cytoplasmic RNA at 24 hr after infection, are largely uncapp...

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

authors： Elroy-Stein O,Fuerst TR,Moss B

更新日期：1989-08-01 00:00:00

abstract：:Declining biodiversity and ecosystem functions put many of nature's contributions to people at risk. We review and synthesize the scientific literature to assess 50-y global trends across a broad range of nature's contributions. We distinguish among trends in potential and realized contributions of nature, as well as ...

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

authors： Brauman KA,Garibaldi LA,Polasky S,Aumeeruddy-Thomas Y,Brancalion PHS,DeClerck F,Jacob U,Mastrangelo ME,Nkongolo NV,Palang H,Pérez-Méndez N,Shannon LJ,Shrestha UB,Strombom E,Verma M

更新日期：2020-12-22 00:00:00

abstract：:Most organisms are evolutionary conservatives; they may subdivide their niches but tend to remain within them. Yet the fossil record shows many cases of breakthrough to a new mode of life. How may such evolutionary innovation be recognized at this time level? Three species of Drosophila have accomplished an innovation...

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

authors： Carson HL

更新日期：1974-09-01 00:00:00

abstract：:Genes encoded by mitochondrial DNA (mtDNA) exist in large numbers per cell but can be selected very rapidly as a result of unequal partitioning of mtDNA between germ cells during embryogenesis. However, empirical studies of this "bottlenecking" effect are rare because of the apparent scarcity of heteroplasmic individu...

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

authors： Van Leeuwen T,Vanholme B,Van Pottelberge S,Van Nieuwenhuyse P,Nauen R,Tirry L,Denholm I

更新日期：2008-04-22 00:00:00

abstract：:Malaria infection triggers vigorous host immune responses; however, the parasite ligands, host receptors, and the signaling pathways responsible for these reactions remain unknown or controversial. Malaria parasites primarily reside within RBCs, thereby hiding themselves from direct contact and recognition by host imm...

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

authors： Wu J,Tian L,Yu X,Pattaradilokrat S,Li J,Wang M,Yu W,Qi Y,Zeituni AE,Nair SC,Crampton SP,Orandle MS,Bolland SM,Qi CF,Long CA,Myers TG,Coligan JE,Wang R,Su XZ

更新日期：2014-01-28 00:00:00

abstract：:Papillomaviruses are small DNA viruses that are associated with benign and malignant epithelial lesions, including >95% of cervical cancers and approximately 20% of head and neck cancers. Because papillomavirus replication and virion production are tied to epithelial cell differentiation, infectious papillomavirus vir...

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

authors： Pyeon D,Lambert PF,Ahlquist P

更新日期：2005-06-28 00:00:00

abstract：:Methane (CH4) impacts climate as the second strongest anthropogenic greenhouse gas and air quality by influencing tropospheric ozone levels. Space-based observations have identified the Four Corners region in the Southwest United States as an area of large CH4 enhancements. We conducted an airborne campaign in Four Co...

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

authors： Frankenberg C,Thorpe AK,Thompson DR,Hulley G,Kort EA,Vance N,Borchardt J,Krings T,Gerilowski K,Sweeney C,Conley S,Bue BD,Aubrey AD,Hook S,Green RO

更新日期：2016-08-30 00:00:00

abstract：:By the use of a rapid radioautographic screening procedure, two mutants of Bacillus brevis ATCC 8185 that have lost the ability to produce gramicidin have been isolated. These mutants produced normal levels of tyrocidine and sporulated at the same frequency as the parent strain. Their spores, however, were more heat-s...

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

authors： Mukherjee PK,Paulus H

更新日期：1977-02-01 00:00:00

abstract：:Transforming growth factor beta (TGF-beta) causes growth arrest in most cell types. TGF-beta induces hypophosphorylation of retinoblastoma susceptibility gene 1 product (RB), which sequesters E2F factors needed for progression into S phase of the cell cycle, thereby leading to cell cycle arrest at G1. It is possible, ...

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

authors： Li JM,Hu PP,Shen X,Yu Y,Wang XF

更新日期：1997-05-13 00:00:00

abstract：:In Drosophila, Pumilio (Pum) is important for neuronal homeostasis as well as learning and memory. We have recently characterized a mammalian homolog of Pum, Pum2, which is found in discrete RNA-containing particles in the somatodendritic compartment of polarized neurons. In this study, we investigated the role of Pum...

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

authors： Vessey JP,Schoderboeck L,Gingl E,Luzi E,Riefler J,Di Leva F,Karra D,Thomas S,Kiebler MA,Macchi P

更新日期：2010-02-16 00:00:00

abstract：:Wild-type Escherichia coli cells grow normally in 95% O(2)/5% CO(2). In contrast, cells that cannot make polyamines because of mutations in the biosynthetic pathway are rapidly killed by incubation in 95% O(2)/5% CO(2). Addition of polyamines prevents the toxic effect of oxygen, permitting cell survival and optimal gr...

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

authors： Chattopadhyay MK,Tabor CW,Tabor H

更新日期：2003-03-04 00:00:00

abstract：:Influenza virus infections cause a wide variety of outcomes, from mild disease to 3 to 5 million cases of severe illness and ∼290,000 to 645,000 deaths annually worldwide. The molecular mechanisms underlying these disparate outcomes are currently unknown. Glycosylation within the human host plays a critical role in in...

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

authors： Heindel DW,Koppolu S,Zhang Y,Kasper B,Meche L,Vaiana CA,Bissel SJ,Carter CE,Kelvin AA,Elaish M,Lopez-Orozco J,Zhang B,Zhou B,Chou TW,Lashua L,Hobman TC,Ross TM,Ghedin E,Mahal LK

更新日期：2020-10-27 00:00:00

abstract：:Cell membrane proteins synthesized after infection of Escherichia coli B with wild-type phage T4 and rIIA mutants were analyzed by dodecyl sulfate-polyacrylamide gel electrophoresis. A protein with an approximate molecular weight of 74,000 is present in membranes isolated from T4r(+)-infected cells, but is not found i...

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

authors： Ennis HL,Kievitt KD

更新日期：1973-05-01 00:00:00

abstract：:The molecular basis for the absence of anthocyanins and proanthocyanidins in four independent sodium azide-induced ant18 mutants of barley was examined by sequencing the gene encoding dihydroflavonol 4-reductase in these mutants. Sodium azide generated 21 base substitutions, which corresponds to 0.17% of the 12,704 nu...

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

authors： Olsen O,Wang X,von Wettstein D

更新日期：1993-09-01 00:00:00

abstract：:Some strains of Bradyrhizobium japonicum produce rhizobitoxine, a phytotoxin that causes foliar chlorosis on susceptible host plants. We have previously obtained Tn5-induced rhizobitoxine null mutants of B. japonicum. DNA sequence analysis of the region surrounding two Tn5 insertions identifies two overlapping open re...

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

authors： Ruan X,Zhang C,Peters NK

更新日期：1993-04-01 00:00:00

abstract：:Serum levels of apolipoprotein CIII (apoCIII) are increased in type 1 diabetic patients, and when β cells are exposed to these diabetic sera, apoptosis occurs, an effect abolished by an antibody against apoCIII. We have investigated the BB rat, an animal model that develops a human-like type 1 diabetes, and found that...

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

authors： Holmberg R,Refai E,Höög A,Crooke RM,Graham M,Olivecrona G,Berggren PO,Juntti-Berggren L

更新日期：2011-06-28 00:00:00

abstract：:Activator-dependent recruitment of TFIID initiates formation of the transcriptional preinitiation complex. TFIID binds core promoter DNA elements and directs the assembly of other general transcription factors, leading to binding of RNA polymerase II and activation of RNA synthesis. How TATA box-binding protein (TBP) ...

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

authors： Wright KJ,Marr MT 2nd,Tjian R

更新日期：2006-08-15 00:00:00

abstract：:The HB-19 pseudopeptide 5[Kpsi(CH(2)N)PR]-TASP, psi(CH(2)N) for reduced peptide bond, is a specific inhibitor of HIV infection in different CD4(+) cell lines and in primary T-lymphocytes and macrophages. It blocks virus-particle attachment to permissive cells by binding and forming a stable complex with nucleolin expr...

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

authors： Krust B,Vienet R,Cardona A,Rougeot C,Jacotot E,Callebaut C,Guichard G,Briand JP,Grognet JM,Hovanessian AG,Edelman L

更新日期：2001-11-20 00:00:00

abstract：:A quantum computer (QC) can operate in parallel on all its possible inputs at once, but the amount of information that can be extracted from the result is limited by the phenomenon of wave function collapse. We present a new computational model, which differs from a QC only in that the result of a measurement is the e...

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

authors： Cory DG,Fahmy AF,Havel TF

更新日期：1997-03-04 00:00:00

abstract：:Protein misfolding is the molecular basis for several human diseases. How the primary amino acid sequence triggers misfolding and determines the benign or toxic character of the misfolded protein remains largely obscure. Among proteins that misfold, polyglutamine (polyQ) expansion proteins provide an interesting case:...

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

authors： Duennwald ML,Jagadish S,Muchowski PJ,Lindquist S

更新日期：2006-07-18 00:00:00