Preparation, characterization and sintering behavior of barium titanate powders coated with Ba-, Ca-, Si- and Ti-containing components

An emulsion technique and spray drying were used to prepare BaTiO3 powders coated with additives. Different additive compositions (TiO2; TiO2/SiO2; CaO/TiO2/SiO2; 2BaO/TiO2/2SiO2) were used in the form of their aqueous precursor solutions. The as-received powders were compared with powders of the same composition manufactured by conventional wet-milling. The coating of the BaTiO3 powder positively influences the sintering behavior. Isothermal dilatometric measurements show that the activation energy &Delta;E of the shrinkage of the coated powders is lower than that of the powders prepared by milling. This is caused by the homogeneous distribution of the additive. The activation energy for the different additives changes in the following sequence: &Delta;E(2BaO/TiO2/2SiO2) < &Delta;E(TiO2) < &Delta;E(CaO/TiO2/SiO2) < &Delta;E(TiO2/SiO2). This sequence correlates with the amount of Ba ions necessary to diffuse out of the BaTiO3 matrix to form the secondary phases Ba2TiSi2O8 or Ba6Ti17O40, respectively

Molecular characterisation of congenital myasthenic syndromes in Southern Brazil

Objective To perform genetic testing of patients with congenital myasthenic syndromes (CMS) from the Southern Brazilian state of Parana. Patients and methods Twenty-five CMS patients from 18 independent families were included in the study. Known CMS genes were sequenced and restriction digest for the mutation RAPSN p.N88K was performed in all patients. Results We identified recessive mutations of CHRNE in ten families, mutations in DOK7 in three families and mutations in COLQ, CHRNA1 and CHRNB1 in one family each. The mutation CHRNE c. 70insG was found in six families. We have repeatedly identified this mutation in patients from Spain and Portugal and haplotype studies indicate that CHRNE c. 70insG derives from a common ancestor. Conclusions Recessive mutations in CHRNE are the major cause of CMS in Southern Brazil with a common mutation introduced by Hispanic settlers. The second most common cause is mutations in DOK7. The minimum prevalence of CMS in Parana is 0.18/100 000

Molecular characterisation of congenital myasthenic syndromes in Southern Brazil

Objective To perform genetic testing of patients with congenital myasthenic syndromes (CMS) from the Southern Brazilian state of Parana. Patients and methods Twenty-five CMS patients from 18 independent families were included in the study. Known CMS genes were sequenced and restriction digest for the mutation RAPSN p.N88K was performed in all patients. Results We identified recessive mutations of CHRNE in ten families, mutations in DOK7 in three families and mutations in COLQ, CHRNA1 and CHRNB1 in one family each. The mutation CHRNE c. 70insG was found in six families. We have repeatedly identified this mutation in patients from Spain and Portugal and haplotype studies indicate that CHRNE c. 70insG derives from a common ancestor. Conclusions Recessive mutations in CHRNE are the major cause of CMS in Southern Brazil with a common mutation introduced by Hispanic settlers. The second most common cause is mutations in DOK7. The minimum prevalence of CMS in Parana is 0.18/100 000

Response of Gram-positive bacteria to copper stress

The Gram-positive bacteria Enterococcus hirae, Lactococcus lactis, and Bacillus subtilis have received wide attention in the study of copper homeostasis. Consequently, copper extrusion by ATPases, gene regulation by copper, and intracellular copper chaperoning are understood in some detail. This has provided profound insight into basic principles of how organisms handle copper. It also emerged that many bacterial species may not require copper for life, making copper homeostatic systems pure defense mechanisms. Structural work on copper homeostatic proteins has given insight into copper coordination and bonding and has started to give molecular insight into copper handling in biological systems. Finally, recent biochemical work has shed new light on the mechanism of copper toxicity, which may not primarily be mediated by reactive oxygen radical

Wanneer sancties tegen Israël?

Although on June 4th president Obama called the situation of the Palestinian population "intolerable", the Israeli government has persisted in crimes against humanity. The authors call for a weapons embargo and political, financial and economic sanctions against Israel

A SUBVENÇÃO DE ORGÂNICOS NO BRASIL E NA UNIÃO EUROPÉIA SOB A ÓTICA DA VISÃO BASEADA EM RECURSOS

Este artigo tem por objetivo a discussão sobre o foco da comercialização dos produtos cítricos orgânicos no Brasil, realizando-se um comparativo entre Brasil e União Européia (UE), sob a ótica da Visão Baseada em Recursos (RBV). Tem-se como fundamentação teórica uma explanação a cerca do mercado europeu de orgânicos cítricos, seguido da situação brasileira dos mesmos, tendo por fim, a teoria da RBV. O estudo possui uma natureza qualitativa, sendo caracterizado por pesquisas exploratórias através da leitura de journals, artigos e também com a realização de, visitas de campo a propriedades rurais e uma cooperativa de produtos orgânicos e. Com base nos dados coletados e na literatura, reuniu-se elementos para a análise e discussão dos resultados, afim de responder à questão-chave da pesquisa, isto é, a comercialização brasileira de cítricos orgânicos deve ser voltada para o mercado interno ou para a União Européia. Face a essa problemática, e considerando os pressupostos da RBV, entende-se haver desvantagem competitiva para o agricultor brasileiro em relação aos produtores de cítricos orgânicos da União Européia, quando o primeiro exporta para o mercado europeu. Assim, entende-se que as estratégias estabelecidas pelos produtores brasileiros de orgânicos, deveriam ter como foco principal o mercado interno para a comercialização de seus produtos. ---------------------------------------------------------This article has as a goal to discuss about the focus on commercialization of organic citric products in Brazil, making a comparative between Brazil and European Community (EC), under the view of the View Based on Resources (RBV). One has as fundamental theory an explanation about the European market of organic citric products, followed by the Brazilian situation of the same ones, having as an aim, the theory of the RBV. This study is of qualitative nature, being characterized by explanatory researches through the reading of journals and articles, as well as field visits to the rural real states and to a cooperative of organic products. Based on the data collected and on the literature, one reunited elements for the analysis and discussion of the results, in order to answer the key question of the research, that is, the Brazilian commercialization of organic citric products must be focused on the domestic market or on the European Market. Owing this problem and considering the requirements of the RBV, one understands to have competitive disadvantage for the Brazilian agriculturist compared to the European Community organic products, when the first exports to the European market. Therefore, one understands that the strategies set up by the Brazilians producers of organic should have as main goal for the commercialization of their products the domestic market.Agronegócios, Cítricos Orgânicos, Subsídios Agrícolas, Agribusiness, Organic Citric, Agricultural Subsidies, Agribusiness, Crop Production/Industries,

Enhanced Proton Acceleration by an Ultrashort Laser Interaction with Structured Dynamic Plasma Targets

We experimentally demonstrate a notably enhanced acceleration of protons to high energy by relatively modest ultrashort laser pulses and structured dynamical plasma targets. Realized by special deposition of snow targets on sapphire substrates and using carefully planned pre-pulses, high proton yield emitted in a narrow solid angle with energy above 21MeV were detected from a 5TW laser. Our simulations predict that using the proposed scheme protons can be accelerated to energies above 150MeV by 100TW laser systems.Comment: Submitted to Physical Review Letter