935 resultados para Richardson, R. H. (Richard Higgins), 1823-1892.


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Arsenic alloying is observed for epitaxial layers nominally intended to be In0.75Ga0.25N. Voids form beneath their interfaces with GaAs substrates, acting as sources of Ga + As out-diffusion into the growing epilayers. As a result, heteroepitaxial single-phase quaternary InxGa1-xAsyN1-y, films are formed with x similar to 0.55 and 0.05 menor que y menor que 0,10. While an undoped epilayer retains the wurtzite structure, a Mn-doped sample showed randomly spaced dopant segregations, which, together with a slightly higher As concentration, led to a transformation from the hexagonal to the twinned cubic phase.

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A Administração Financeira surge no início do século XIX juntamente com o movimento de consolidação das grandes empresas e a formação dos mercados nacionais americano enquanto que no Brasil os primeiros estudos ocorrem a partir da segunda metade do século XX. Desde entãoo país conseguiu consolidar alguns centros de excelência em pesquisa, formar grupo significativo de pesquisadores seniores e expandir as áreas de pesquisa no campo, contudo, ainda são poucos os trabalhos que buscam retratar as caractersticas da produtividade científica em Finanças. Buscando contribuir para a melhor compreensão do comportamento produtivo dessa área a presente pesquisa estuda sua produção científica, materializada na forma de artigos digitais, publicados em 24 conceituados periódicos nacionais classificados nos estratos Qualis/CAPES A2, B1 e B2 da Área de Administração, Ciências Contábeis e Turismo. Para tanto são aplicadas a Lei de Bradford, Lei do Elitismo de Price e Lei de Lotka. Pela Lei de Bradford são identificadas trs zonas de produtividade sendo o núcleo formado por trs revistas, estando uma delas classificada no estrato Qualis/CAPES B2, o que evidencia a limitação de um recorte tendo como único cririo a classificação Qualis/CAPES. Para a Lei do Elitismo de Price, seja pela contagem direta ou completa, não identificamos comportamento de uma elite semelhante ao apontado pela teoria e que conta com grande número de autores com apenas uma publicação.Aplicando-se o modelo do Poder Inverso Generalizado, calculado por Mínimos Quadrados Ordinários (MQO), verificamos que produtividade dos pesquisadores, quando feita pela contagem direta, se adequa àquela definida pela Lei de Lotka ao nível de α = 0,01 de significância, contudo, pela contagem completa não podemos confirmar a hipótese de homogeneidade das distribuições, além do fato de que nas duas contagens a produtividade analisada pelo parmetro n é maior que 2 e, portanto, a produtividade do pesquisadores de finanças é menor que a defendida pela teoria.

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Adenoviral vectors were used to deliver genes encoding a soluble interleukin 1 (IL-1)-type I receptor-IgG fusion protein and/or a soluble type I tumor necrosis factor α (TNFα) receptor-IgG fusion protein directly to the knees of rabbits with antigen-induced arthritis. When tested individually, knees receiving the soluble IL-1 receptor had significantly reduced cartilage matrix degradation and white blood cell infiltration into the joint space. Delivery of the soluble TNFα receptor was less effective, having only a moderate effect on white blood cell infiltration and no effect on cartilage breakdown. When both soluble receptors were used together, there was a greater inhibition of white blood cell infiltration and cartilage breakdown with a considerable reduction of synovitis. Interestingly, anti-arthritic effects were also seen in contralateral control knees receiving only a marker gene, suggesting that sustained local inhibition of disease activity in one joint may confer an anti-arthritic effect on other joints. These results suggest that local intra-articular gene transfer could be used to treat systemic polyarticular arthritides.

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Funding Information This work was supported by the Biotechnology and Biological Sciences Research Council (BB/J015911/1)

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Neurotoxicity induced by overstimulation of N-methyl-d-aspartate (NMDA) receptors is due, in part, to a sustained rise in intracellular Ca2+; however, little is known about the ensuing intracellular events that ultimately result in cell death. Here we show that overstimulation of NMDA receptors by relatively low concentrations of glutamate induces apoptosis of cultured cerebellar granule neurons (CGNs) and that CGNs do not require new RNA or protein synthesis. Glutamate-induced apoptosis of CGNs is, however, associated with a concentration- and time-dependent activation of the interleukin 1β-converting enzyme (ICE)/CED-3-related protease, CPP32/Yama/apopain (now designated caspase 3). Further, the time course of caspase 3 activation after glutamate exposure of CGNs parallels the development of apoptosis. Moreover, glutamate-induced apoptosis of CGNs is almost completely blocked by the selective cell permeable tetrapeptide inhibitor of caspase 3, Ac-DEVD-CHO but not by the ICE (caspase 1) inhibitor, Ac-YVAD-CHO. Western blots of cytosolic extracts from glutamate-exposed CGNs reveal both cleavage of the caspase 3 substrate, poly(ADP-ribose) polymerase, as well as proteolytic processing of pro-caspase 3 to active subunits. Our data demonstrate that glutamate-induced apoptosis of CGNs is mediated by a posttranslational activation of the ICE/CED-3-related cysteine protease caspase 3.

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Synaptic vesicle protein 2 (SV2) is a membrane glycoprotein common to all synaptic and endocrine vesicles. Unlike many proteins involved in synaptic exocytosis, SV2 has no homolog in yeast, indicating that it performs a function unique to secretion in higher eukaryotes. Although the structure and protein interactions of SV2 suggest multiple possible functions, its role in synaptic events remains unknown. To explore the function of SV2 in an in vivo context, we generated mice that do not express the primary SV2 isoform, SV2A, by using targeted gene disruption. Animals homozygous for the SV2A gene disruption appear normal at birth. However, they fail to grow, experience severe seizures, and die within 3 weeks, suggesting multiple neural and endocrine deficits. Electrophysiological studies of spontaneous inhibitory neurotransmission in the CA3 region of the hippocampus revealed that loss of SV2A leads to a reduction in action potential-dependent γ-aminobutyric acid (GABA)ergic neurotransmission. In contrast, action potential-independent neurotransmission was normal. Analyses of synapse ultrastructure suggest that altered neurotransmission is not caused by changes in synapse density or morphology. These findings demonstrate that SV2A is an essential protein and implicate it in the control of exocytosis.

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We have expanded the field of “DNA computers” to RNA and present a general approach for the solution of satisfiability problems. As an example, we consider a variant of the “Knight problem,” which asks generally what configurations of knights can one place on an n × n chess board such that no knight is attacking any other knight on the board. Using specific ribonuclease digestion to manipulate strands of a 10-bit binary RNA library, we developed a molecular algorithm and applied it to a 3 × 3 chessboard as a 9-bit instance of this problem. Here, the nine spaces on the board correspond to nine “bits” or placeholders in a combinatorial RNA library. We recovered a set of “winning” molecules that describe solutions to this problem.