Redox regulation of protein tyrosine phosphatase 1B (PTP1B): Importance of steric and electronic effects on the unusual cyclization of the sulfenic acid intermediate to a sulfenyl amide

The redox regulation of protein tyrosine phosphatase 1B (PTP1B) via the unusual transformation of its sulfenic acid (PTP1B-SOH) to a cyclic sulfenyl amide intermediate is studied by using small molecule chemical models. These studies suggest that the sulfenic acids derived from the H2O2-mediated reactions o-amido thiophenols do not efficiently cyclize to sulfenyl amides and the sulfenic acids produced in situ can be trapped by using methyl iodide. Theoretical calculations suggest that the most stable conformer of such sulfenic acids are stabilized by n(O) -> sigma* (S-OH) orbital interactions, which force the -OH group to adopt a position trans to the S center dot center dot center dot O interaction, leading to an almost linear arrangement of the O center dot center dot center dot S-O moiety and this may be the reason for the slow cyclization of such sulfenic acids to their corresponding sulfenyl amides. On the other hand, additional substituents at the 6-position of o-amido phenylsulfenic acids that can induce steric environment and alter the electronic properties around the sulfenic acid moiety by S center dot center dot center dot N or S center dot center dot center dot O nonbonded interactions destabilize the sulfenic acids by inducing strain in the molecule. This may lead to efficient the cyclization of such sulfenic acids. This model study suggests that the amino acid residues in the close proximity of the sulfenic acid moiety in PTP1B may play an important role in the cyclization of PTP1B-SOH to produce the corresponding sulfenyl amide.

On the absence of shear cracking and grain boundary cavitation in secondary tensile regions of Ti-6Al-4V-0.1B alloy during hot (alpha plus beta)-compression

Deformation instabilities, such as shear cracking and grain boundary cavitation, which are observed in the secondary tensile region of Ti-6Al-4V alloy during compressive deformation in the (+)-phase field, do not form in Ti-6Al-4V-0.1B alloy when processed under the same conditions. This has been attributed to the microstructural modifications, e.g. the absence of grain boundary and adjacent grain boundary retained layers and a lower proportion of 90(o)-misoriented -colonies that occur with boron addition.

Crystallographic texture and microstructure evolution during hot compression of Ti-6Al-4V-0.1B alloy in the (alpha plus beta)-regime

Microstructure and texture are known to undergo drastic modifications due to trace hypoeutectic boron addition (similar to 0.1wt.%) for various titanium alloys e.g. Ti-6Al-4V. The deformation behaviour of such an alloy Ti-6Al-4V-0.1B is investigated in the (+) phase field and compared against that of the base alloy Ti-6Al-4V studied under selfsame conditions. The deformation microstructures for the two alloys display bending and kinking of lamellae in near and softening via globularization of lamella in near phase regimes, respectively. The transition temperature at which pure slip based deformation changes to softening is lower for the boron added alloy. The presence of TiB particles is largely held attributable for the early softening of Ti-6Al-4V-0.1B alloy. The compression texture of both the alloys carry signature of pure phase defamation at lower temperature and phase transformation near the transus temperature. Texture is influenced by a complex interplay of the deformation and transformation processes in the intermediate temperature range. The contribution from phase transformation is prominent for Ti-6Al-4V-0.1B alloy at comparatively lower temperature.

Enhanced superplasticity for (alpha plus beta)-hot rolled Ti-6Al-4V-0.1B alloy by means of dynamic globularization

Thermo-mechanically processed Ti-6Al-4V alloy, with (0.1 wt.%) and without boron addition, has been subjected to tensile test under superplastic deformation conditions (Temperature, T = 850 degrees C and initial strain rate, (epsilon) over dot = 3 x 10(-4) s(-1)). The boron added alloy exhibited higher elongation (similar to 430%) in comparison to the base alloy without boron (similar to 365%). Superior ductility of the boron added alloy has been attributed to an enhanced alpha/beta interfacial boundary sliding. This was caused by riotous dynamic globularization leading to the abundant presence of equiaxed primary alpha grains with refined sizes and narrow distribution in the deforming microstructure. Cavities do occur around TiB particles during deformation; the cavities are, however, extremely localized and do not cause macroscopic cracking. (C) 2014 Elsevier Ltd. All rights reserved.

Self-recruiting species (SRS) from farmer managed aquatic systems: are they important to the livelihoods of rural communities?

Why are SRS important? The answer is to be found in this well-structured survey under: SRS as food source; SRS as additional source of cash income; Role of SRS in social capital. An analysis of the threats to SRS and the potential management options for farmer managed aquatic systems are also available in this survey along with the following definition of SRS: SRS are defined as aquatic animals that can be harvested from farmer managed aquatic systems without regular stocking. (PDF contains 4 pages)

Memoria historica da Estrada de Ferro Central do Brazil / organizada por Manuel Fernandes Figueira ; e publicada por ordem da Directoria e autorisação do Ministério da Industria, Viação e Obras Publicas por occasião de celebrar-se aos 29 de março de 1908 o 50º anniversavio da inauguração do trafego do primeiro trecho, sob as vistas dos Srs. Drs. João José de S. Paulo ..., Carlos Euler, ..., e José Ascanio Burlamaqui, ..., sendo o director da estrada Dr. Aarão Reis

Referência: Fundação Biblioteca Nacional.

Fallas do throno, desde o anno de 1823 ate o anno de 1872, acompanhadas dos respectivos votos de graças da Camara Temporaria e de differentes informações e esclarecimentos / colligidas na Secretaria da Camara dos Srs. Deputados

Contém uma relação de todos os deputados brasileiros desde as cortes portuguesas e a constituinte até a 14ª legislatura ordinária.

Relatorios e Synopses dos trabalhos parlamentares da Câmara dos Srs. Deputados : organizados na Secretaria da mesma Camara : 1869 - 1874

Sinopse dos trabalhos da Câmara dos Deputados, de 1869 a 1874.

Relatorio e synopse dos trabalhos da Camara dos Srs. Deputados : na 1ª e 2ª sessão do anno de 1879

Sinopse dos trabalhos da Câmara dos Deputados, em 1879.

Relatorio e synopse dos trabalhos da Câmara dos Srs. Deputados : na sessão do anno de 1874 : acompanhada de differentes documentos e mapas estatísticos, organizados na Secretaria da mesma Camara

Sinopse dos trabalhos da Câmara dos Deputados, em 1874.

Relatorio e synopse dos trabalhos da Camara dos Srs. Deputados : na 1ª e 2ª sessão do anno de 1877 : acompanhada de differentes documentos, e mappas estatisticos, organisados na Secretaria da mesma Camara

Sinopse dos trabalhos da Câmara dos Deputados, em 1877.

Relatorio e synopse dos trabalhos da Camara dos Srs. Deputados : nas sessões do anno de 1880 : acompanhada de differentes documentos, quadros estatisticos e informações : organizados na Secretaria da Camara dos Deputados

Sinopse dos trabalhos da Câmara dos Deputados, em 1880.