Effect of an ancillary ligand on single helix-double helix interconversion in copper complexes. Copper(I)-water bond

Reaction of Cu(ClO(4))(2)center dot 6H(2)O with the 1:2 condensate of benzildihydrazone and 2-acetylpyridine, in methanol in equimolar ratio yields a green compound which upon recrystallisation from 1:1 CH(2)Cl(2)-C(6)H(6) mixture affords [CuL(H(2)O)](ClO(4))(2)center dot 1/2C(6)H(6). The complex crystallises in the space group P-1 with a = 8.028(11) angstrom, b = 12.316(17) angstrom, c = 18.14(3) angstrom, alpha = 97.191(10)degrees, beta = 94.657(10)degrees and gamma = 108.039(10)degrees. It is single helical with the metal having a distorted trigonal bipyramidal N(4)O coordination sphere. The acid dissociation constant of the Cu(I) complex in CH(3)CN is 3.34 +/- 0.19. The X band EPR spectrum of the compound is rhombic with g(1) = 2.43, g(2) = 2.10 g(3) = 2.02 and A(1) = 79.3 x 10(-4) cm(-1). The Cu(II/I) potential of the complex in CH(2)Cl(2) at a glassy carbon electrode is 0.43 V vs SCE. It is argued that the copper-water bond persists in the corresponding copper(I) species. Its implications on the single helix-double helix interconversion in copper helicates are discussed. DFT calculations at the B3LYP/6-311G** level shows that the binding energy of water in the single helicol live-coordinate copper(I) species [CuL(H(2)O)](+) is similar to 40 kJ mol(-1).

Caracterização da resistência a corrosão de camadas obtidas por nitretação a plasma e deposição física de vapor sobre aço inoxidável AISI 316 L

A técnica de revestimento duplex combina dois processos: o tratamento de nitretação a plasma da superfície e a deposição de uma camada via PVD. O processo de nitretação a plasma sob condições controladas pode produzir a chamada “fase S” sem a presença de nitretos de cromo, o que confere ao aço tratado maior dureza e melhor resistência à corrosão. Os revestimentos de nitreto de titânio melhoram a dureza superficial do material, porém defeitos e poros podem expor o substrato ao meio. Este trabalho consiste no estudo da resistência à corrosão do aço inoxidável austenítico AISI 316L revestido com camada duplex em meio contendo cloretos. As camadas nitretadas a plasma foram obtidas pelo processo de nitretação iônica e os revestimentos Ti/TiN foram obtidos pelo processo de deposição física de vapor assistida por plasma (PAPVD). Os corpos de prova foram inicialmente avaliados por microscopia eletrônica de varredura (MEV) e a composição das fases foi identificada por difração de raios-x (DRX). A dureza foi avaliada por nanoidentação e a rugosidade superficial também foi medida. Os testes de resistência à corrosão foram feitos por voltametria cíclica (VC) e os ensaios de corrosão acelerada em câmara de névoa salina. A amostra nitretada a 400°C por 4 horas e mistura gasosa de 5%N2- 95%H2 apresentou o melhor desempenho de resistência à corrosão em meio contendo cloretos. A resistência à corrosão foi associada à estrutura obtida após o tratamento por nitretação a plasma e deposição física de vapores (PVD).

Reforma tributária no Brasil: efeitos alocativos e impactos de bem-estar

Neste artigo realizam-se quantificações e qualificações dos efeitos alocativos e dos impactos sobre o bem-estar que possíveis reformas tributárias poderiam ocasionar na economia brasileira. Para tanto, recorre-se a experimentos computacionais para simulação e mensuração dos resultados. No que se refere aos efeitos alocativos, conclui-se que as reformas tributárias correntemente propostas trariam resultados positivos, com crescimento do produto, emprego e estoque de capital da economia. Já no que se refere aos impactos de bem-estar, constata-se que o padrão de vida da sociedade poderia melhorar.

Capitalização de Juros: possíveis efeitos da ADI 2.316

Em instigante artigo, Domingues (2011), que ainda permanece muito relevante e atual, e em que se faz uso da alegoria simbolizada pela espada de Dâmocles, somos alertados para possíveis efeitos da Ação Direta de Inconstitucionalidade (ADI) 2.316, que foi proposta no já longínquo ano de 2000, pelo antigo Partido Liberal. Tal ADI 2.316, que continua pendente de definição por parte do Supremo Tribunal Federal (STF), diz respeito ao artigo 5º da Medida Provisória (MP) 2.170–36/2001, que estabelece: “Art. 5º. Nas operações realizadas pelas instituições integrantes do Sistema Financeiro Nacional, é admissível a capitalização de juros com periodicidade inferior a um ano.” Ou seja, em outras palavras, ainda não há decisão final, pois que o STF não concluiu sua apreciação da matéria, sobre se o chamado regime de juros compostos pode ser empregado em prazos que sejam frações do ano.

Nitriding in cathodic cage of stainless steel AISI 316: influence of sample position

R.R.M. de Sousa et al. Nitriding in cathodic cage of stainless steel AISI 316: Influence of sample position. Vacuum, [s.l.], n.83, 2009. Disponivel em: . Acesso em: 04 out.2010.

A Comparati ve Study of Mechanical and Tribological Properties of AISI-304 and AISI-316 Submitted to Glow Discharge Nitriding

Mechanical and tribological properties of AISI 304 and AISI 316 stainless steels submitted to glow discharge ion nitriding are reported. The atmosphere was 20:80 - N2:H2 with substrate temperatures ranging from 300 to 500 °C. Treatment at 300 °C produced expanded austenite (γN) in both steels. Increasing the temperature, the phases γ′-Fe4N and ε- Fe2+xN were present and the latter is the major phase for AISI 304. At 500 °C, the CrN phase was also identified in both steels. Hardnesses of about 13-14 GPa at near surface regions were obtained in both steels. Moreover, AISI 316 nitrided at 500 °C has the deepest hard layer. Tribological tests showed that wear can be reduced by up to a factor of six after the nitriding processes, even for a working temperature of 300 °C. The profiles during and after nanoscratch tests did not reveal significant differences after nitriding processes in both steels.

A Comparative Study of Mechanical and Tribological Properties of AISI-304 and AISI-316 Submitted to Glow Discharge Nitriding

Mechanical and tribological properties of AISI 304 and AISI 316 stainless steels submitted to glow discharge ion nitriding are reported. The atmosphere was 20:80 - N2:H2 with substrate temperatures ranging from 300 to 500 °C. Treatment at 300 °C produced expanded austenite (γN) in both steels. Increasing the temperature, the phases γ′-Fe4N and ε- Fe2+xN were present and the latter is the major phase for AISI 304. At 500 °C, the CrN phase was also identified in both steels. Hardnesses of about 13-14 GPa at near surface regions were obtained in both steels. Moreover, AISI 316 nitrided at 500 °C has the deepest hard layer. Tribological tests showed that wear can be reduced by up to a factor of six after the nitriding processes, even for a working temperature of 300 °C. The profiles during and after nanoscratch tests did not reveal significant differences after nitriding processes in both steels.

Population structure, distribution and abundance patterns of the patagonian smoothhound Musmlus schmitti springer, 1939 (Chondrichthyes,Elasmobranchii, Triakidae) in the rio de la plata and inner continental shelf, SW Atlantic ocean (34 degrees-30'-39 degrees-30's)

A total number of 4824 Mustelus schmitti was sampled. Females ranged from 25 to 93 em in spring and from 28 to 90 cm in summer. Males ranged from 34 to 82 and from 28 to 77 cm, respectively. Length composition of the population showed significant differences between spring and summer being females larger than males. Total length distribution did not show significant differences between cruises. Males density varied significantly between cruises while for the females no significant variation was observed. In the spring cruise, both sexes occurred at depths lower than 50 in. Females occurred in the whole area with adult occurrence only above 35 degrees 30'S. Mature males occurred throughout the area, immature males occurring in two trawls in Samborombon Bay. The summer cruise showed a discontinuous distribution of the species along the study area resulting in spatial segregation in two groups with immature females predominating in both of them.

Avaliação da Gravidade Específica e de Outras Medidas Corporais e da Carcaça para Estimar a Composição Corporal de Novilhos Nelore

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Digestibility, fermentation and rumen microbiota of crossbred heifers fed diets with different soybean oil availabilities in the rumen

The goal of this study was to evaluate the effects of different soybean oil availabilities on the intake and partial and total digestibility of dry matter (DM) and nutrients, rumen fermentation parameters, efficiency of microbial synthesis, and the rumen microbiota of crossbred beef heifers. Nine crossbred heifers fitted with rumen and duodenal cannulae were evaluated in a triple 3 × 3 Latin square design with three treatments and three periods in three simultaneous repetitions. Heifers approximately 18 months old, with mean initial and final body weights of 316.3±28.8 and 362.6±34.4 kg, respectively, were fed a diet containing 600. g/kg of corn silage and 400. g/kg concentrate with a 58.0. g/kg fat content in the total diet. The sources of lipids included soybean grain, rumen-protected fat, and soybean oil. The statistical analyses were conducted using PROC MIXED from SAS, and the means were compared using Tukey's test (P<0.05). Dietary lipid sources did not affect nutrient intake (P>0.05). Except the apparent digestibility of organic matter (P=0.024), the apparent digestibility of the other nutrients did not differ among the treatment groups. Regarding body nitrogen retention, the soybean grain treatment was more effective than the rumen-protected fat treatment (P=0.045); however, the soybean oil treatment did not differ from the other two treatments. In relation to the efficiency of microbial protein synthesis (g. N/kg of organic matter apparently digested in the rumen corrected for microbial organic matter), the soybean oil and soybean grain treatments were more efficient than the rumen-protected fat treatment (P=0.001). Animals fed rumen-protected fat had larger numbers of protozoa (P<0.001) and fungi (P<0.001) than those supplemented with soybean grain and soybean oil. The dietary lipid sources did not affect pH, the molar concentration of propionate and total volatile fatty acids (P>0.05), whereas the concentrations of ammonia nitrogen and acetate were higher in animals fed with rumen-protected fat than in those submitted to the other treatments. The use of different soybean oil availabilities did not affect nutrient intake; however, treatments with soybean oil and soybean grain were more efficient regarding nutrient intake than rumen-protected fat because they reduced the numbers of fungi and protozoa and consequently improved the efficiency of microbial protein synthesis. © 2013 Elsevier B.V.