996 resultados para 310-M0023A


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Boc-Trp-Ile-Ala-Aib-Ile-Val-Aib-Leu-Aib- Pro-Ala-Aib-Pro-Aib-Pro-Phe-OM(we here Boc is t-butoxycarbonyla nd Aib is a-aminoisobutyriac cid), a synthetica polar analog of the membrane-activefu ngal peptide antibioticz ervamtycinII A, crystallizesi n spaceg roupP 1 withZ =1 and cell parameters a = 9.086 ?0.002 A, b = 10.410 ?+ 0.002 A, c = 28.188 ? 0.004 A, a = 86.13 ? 0.01?, 13 = 87.90 ? 0.01?, and y = 89.27 ? 0.01?;o veralla greementf actorR = 7.3% for 7180 data (Fo > 3cr) and 0.91-A resolution. The peptide backbone makes a continuous spiral that begins as a 310-helix at the N-terminus, changes to an a-helix for two turns, and ends in a spiral of three fl-bends in a ribbon. Each of the fl-bends contains a proline residue at one of the corners. The torsion angles 4i range from -51? to -91? (average value -64o), and the torsion angles ai range from -1? to -46? (average value -31?). There are 10 intramolecularN H...OCh ydrogenb onds in the helix and two directh ead-to-taihl ydrogenb ondsb etween successive molecules. Two H20 and two CH30H solvent molecules fill additional space with appropriate hydrogen bonding in the head-to-tail region, and two additional H20 molecules form hydrogen bonds with carbonyl oxygens near the curve in the helix at Pro-10. Since there is only one peptide molecule per cell in space group P1, the molecules repeat only by translation, and consequently the helices pack parallel to each other.

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Corrosion of SAE 310 stainless steel in H2-H2O-H2S gas mixtures was studied at a constant temperature of 1150 K. Reactive gas mixtures were chosen to yield a constant oxygen potential of approximately 6 × 10-13 Nm-2 and sulfur potentials ranging from 0.19 × 10-2 Nm-2 to 33 × 10-2 Nm-2. The kinetics of corrosion were determined using a thermobalance, and the scales were analyzed using metallography, scanning electron microscopy, and energy dispersive X-ray analysis. Two corrosion regimes, which were dependent on sulfur potential, were identified. At high sulfur potentials (P S 2 ± 2.7 × 10-2 Nm-2) the corrosion rates were high, the kinetics obeyed a linear rate equation, and the scales consisted mainly of sulfide phases similar to those observed from pure sulfidation. At low sulfur potentials (P S 2 ± 0.19 × 10-2 Nm-2) the corrosion rates were low, the kinetics obeyed a parabolic rate equation, and scales consisted mainly of oxide phases. Thermochemical diagrams for the Fe-Cr-S-O, Fe-Ni-S-O, Cr-Ni-S-O, and Si-Cr-S-O systems were constructed, and the experimental results are discussed in relation to these diagrams. Based on this comparison, reasonable corrosion mechanisms were developed. At high sulfur potentials, oxide and sulfide phases initially nucleate as separate islands. Overgrowth of the oxide by the sulfide occurs and an exchange reaction governs the corrosion process. Preoxidation at low oxygen potentials and 1150 K is beneficial in suppressing sulfidation at high sulfur potentials.

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Na Comissão de Sistematização tem início a votação da ordem social. Em relação à educação, o projeto do Deputado Bernardo Cabral (PMDB-AM) prevê que o Estado garanta ensino fudamental para todos. O Deputado Tadeu França (PMDB-PR) ressalta que 87% das crianças brasileiras não concluem o 1º grau, contudo é preciso resgatar a escola pública, para que esta possa ser a grande vanguarda de tranformação nacional. O Deputado Sólon Borges Reis (PTB-SP) afirma que a nova constituiçao traz mais estímulos aos professores, com a manutenção da aposentadoria especial. No próximo domigo tem início a votação do último título do projeto, referente às disposições transitórias, que contém o mandato do Presidente da República. Os Deputados Roberto Freire (PCB-PE), José Lourenço (PFL-BA) e Egídio Ferreira Lima (PMDB-PE) declaram suas posições à respeito do mandato do Presidente da República e a implantação do parlamentarismo. No dia 17 de novembro será concluída a votação de todo o projeto da Sistematização. E no dia 20 de novembro tem início a votação no Plenário da Assembléia Nacional Constiuinte (ANC). O grupo "Centrão" quer alterar o Regimento Interno, para permitir a apresentação de emendas. O Deputado Chagas Netos (PMDB-RO) considera que o Centrão não forma um bloco coeso em suas propostas.

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2004

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Jornal elaborado pela Assessoria de Comunicação e Imprensa da Reitoria da UNESP

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