810 resultados para Catilina, Lucio Sergio, 108-62 a.C


Relevância:

30.00% 30.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The rate coefficients for the formation of carbon monophosphide (CP) and silicon monophosphide (SiP) by radiative association are estimated for temperatures ranging from 300 to 14 100 K. In this temperature range, the radiative association rate coefficients are found to vary from 1.14 x 10(-18) to 1.62 x 10(-18) cm(3) s(-1) and from 3.73 x 10(-20) to 7.03 x 10(-20) cm(3) s(-1) for CP and SiP, respectively. In both cases, rate coefficients increase slowly with the increase in temperature.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Nos últimos 30 anos não foram levadas em consideração questões metodológicas importantes relativas ao estudo da fenologia de plantas. O uso de vários métodos na amostragem e avaliação dos dados fenológicos tem levado a uma grande dificuldade na interpretação e comparação de resultados. Esse estudo tem por objetivos realizar uma revisão da literatura em fenologia de florestas tropicais, compilando informações sobre os métodos de amostragem e avaliação utilizados, e discutir as proporções em que foram utilizados e as aplicações de cada método. Nos 60 estudos avaliados, os métodos de amostragem encontrados distribuem-se da seguinte forma: trilhas (20%), transecções (18%), parcelas (15%), coletores (10%), sendo que 37% dos estudos não definiram o método de amostragem utilizado. Para avaliação fenológica foram levantados dois métodos: qualitativo, presença e ausência das fenofases (20%) e quantitativo com quantificação da intensidade das fenofases (62%), e a combinação entre métodos qualitativos e quantitativos (17%). Ao longo do tempo cresceu a preocupação com a aplicação de métodos de amostragem e de avaliação quantitativa. Entretanto, a falta de padronização no uso desses métodos, mesmo nos dias atuais, ainda se faz presente, resultando na impossibilidade de comparação adequada dos estudos. É imprescindível, portanto, a realização de estudos comparativos de métodos fenológicos com espécies arbóreas em florestas tropicais.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

OBJETIVO: Estudar a eficácia e a segurança da cardioplegia sanguínea, aterógrada-retrógrada contínua, por meio da avaliação da função ventricular. MÉTODOS: Os coelhos foram divididos em quatro grupos: Controle-C(n=10); isquêmico e cardioplegia cristaloide-IC(n=10; isquêmico e cardioplegia sanguínea-IB(n=10; isquêmico sem cardioplegia-INC(n=10. Após o período isquêmico do protocolo a função ventricular foi analisada pela técnica do balão intra-ventricular. RESULTADOS: a pressão desenvolvida intra-ventricular (IVDP) foi: C(92,90± 6,86mmHg); IC(77,78± 6,15mmHg); IB(93,64 ±5,09mmHg); INC(39,46 ±8,91mmHg) p<0,005. a primeira derivada temporal da pressão ventricular na sua deflexão positiva: C(1137,50± 92,23mmHg/sec); IC(1130,62 ±43,78mmHg/sec); IB(1187,58± 88,38mmHg/sec); INC(620,02± 43,80mmHg/se) p<0,005. A primeira derivada da pressão ventricular na sua deflexão negativa: C(770,00± 73,41mmHg/sec); IC(610,03 ±47,43mmg/sec); IB(762,53 ±46,02mmHg/sec); INC(412,35 ±84,36mmHg/sec) p<0,005. A relação do coeficiente angular logarítmico foi: C(0,108± 0,02); IC(0,159± 0,038); IB(0,114 ±0,016); INC(0,175± 0,038) p<0,05. CONCLUSÃO: No modelo experimental estudado o grupo isquêmico protegido pela cardioplegia sanguínea apresentou melhor função ventricular que os grupos protegidos por cardioplegia cristalóide e não protegido.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

O presente trabalho teve como objetivo avaliar os efeitos da suplementação de vitamina C e E sobre o desenvolvimento e sobrevivência de girinos de rã-touro. Os animais receberam 50, 250 e 500mg de vitamina C ou E/kg de ração, distribuídos segundo delineamento inteiramente casualizado com 3 repetições cada. Na dieta controle, não foram adicionadas vitaminas. Os girinos suplementados com vitamina C ou E não apresentaram diferença significativa no crescimento, comparados ao controle. Não obstante, os suplementados com 500mg de vitamina C apresentaram melhor sobrevivência (62,83%) do que os animais controle (40,48%; p<0,05), nos demais níveis desta vitamina e a adição de vitamina E não alteraram a sobrevivência. O presente trabalho sugere que 500mg de vitamina C/kg de ração constitui uma opção para melhorar a sobrevivência de girinos de rã-touro.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

In order to know which stage of fruit development is better for acerola industrialization, we studied the PME specific activity, pectin content and vitamin C at various stages of development. The acerola fruits were classified according to colour and weight in five stages: immature green (2.62-3.21 g), green (4.04-4.83 g), mature green/yellow (5.03-5.88 g), pale-red (6.16-6.77 g) and ripe mature (6.92-8.37 g). The results showed that the highest content of pectin and vitamin C occurred at the immature green stage, 4.51 +/- 0.1% yield, 2424 mg/100 g of pulp and decreased as fruit ripened, 2.99 +/- 0.03% yield, 957 +/- 0.0 mg/100 g of pulp, respectively. However, at the same stages, the values of PME specific activity were lowest, 0.61 +/- 0.01 and 0.55 +/- 0.0 units g(-1)/g of pulp, respectively. The highest value of PME activity was 2.08 +/- 0.01 units g(-1)/g of pulp in the green stage. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Bismuth was evaluated as an internal standard for the direct determination of Pb in vinegar by graphite furnace atomic absorption spectrometry using Ru as a permanent modifier with co-injection of Pd/Mg(NO3)(2). The correlation coefficient of the graph plotted from the non-nalized absorbance signals of Bi versus Pb was r=0.989. Matrix effects were evaluated by analyzing the slope ratios between the analytical curve, and analytical curves obtained from Pb additions in red and white wine vinegar obtained from reference solutions prepared in 0.2% (v/v) HNO3, samples. The calculated ratios were around 1.04 and 1.02 for analytical curves established applying an internal standard and 1.3 and 1.5 for analvtical curves without. Analytical curves in the 2.5-15 pg L-1 Pb concentration interval were established using the ratio Pb absorbance to Bi absorbance versus analvte concentration, and typical linear correlations of r=0.999 were obtained. The proposed method was applied for direct determination of Pb in 18 commercial vinegar samples and the Pb concentration varied from 2.6 to 31 pg L-1. Results were in agreement at a 95% confidence level (paired t-test) with those obtained for digested samples. Recoveries of Pb added to vinegars varied from 96 to 108% with and from 72 to 86% without an internal standard. Two water standard reference materials diluted in vinegar sample were also analyzed and results were in agreement with certified values at a 95% confidence level. The characteristic mass was 40 pg Pb and the useful lifetime of the tube was around 1600 firings. The limit of detection was 0.3 mu g L-1 and the relative standard deviation was <= 3.8% and <= 8.3% (n = 12) for a sample containing, 10 mu L-1 Pb with and without internal standard, respectively. (C) 2007 Elsevier B.V. All rights reserved.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Gigahertz conductivity of pressed pellets of ClO4--doped poly( 3-methylthiophene) can be readily obtained from the asymmetry ratio (A / B) of the electron spin resonance line using Dyson's theory. The measurements were performed in three different frequencies, 1.3, 9.4, and 35 GHz. The temperature dependence of the gigahertz conductivity is sensitive to the heating rate, probably due to the ordering of the randomly assembled anions. (C) 1994 Academic Press, Inc.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

OBJECTIVE: To study whether antioxidant supplementation will reduce the incidence of preeclampsia among patients at increased risk.METHODS: A randomized, placebo-controlled, double-blind clinical trial was conducted at four Brazilian sites. Women between 12 0/7 weeks and 19 6/7 weeks of gestation and diagnosed to have chronic hypertension or a prior history of preeclampsia were randomly assigned to daily treatment with both vitamin C (1,000 mg) and vitamin E (400 International Units) or placebo. Analyses were adjusted for clinical site and risk group (prior preeclampsia, chronic hypertension, or both). A sample size of 734 would provide 80% power to detect a 40% reduction in the risk of preeclampsia, assuming a placebo group rate of 21% and alpha=.05. The a level for the final analysis, adjusted for interim looks, was 0.0458.RESULTS: Outcome data for 707 of 739 randomly assigned patients revealed no significant reduction in the rate of preeclampsia (study drug, 13.8% [49 of 355] compared with placebo, 15.6% [55 of 352], adjusted risk ratio 0.87 [95.42% confidence interval 0.61-1.25]). There were no differences in mean gestational age at delivery or rates of perinatal mortality, abruptio placentae, pre-term delivery, and small for gestational age or low birth weight infants. Among patients without chronic hypertension, there was a slightly higher rate of severe preeclampsia in the study group (study drug, 6.5% [11 of 170] compared with placebo, 2.4% [4 of 168], exact P=.11, odds ratio 2.78, 95% confidence interval 0.79-12.62).CONCLUSION: This trial failed to demonstrate a benefit of antioxidant supplementation in reducing the rate of preeclampsia among'patients with chronic hypertension and/or prior preeclampsia.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Monocrotaline is a pyrrolizidine alkaloid present in plants of the Crotalaria species, which causes cytotoxicity and genotoxicity, including hepatotoxicity in animals and humans. It is metabolized by cytochrome P-450 in the liver to the alkylating agent dehydromonocrotaline. We evaluated the effects of monocrotaline and its metabolite on respiration, membrane potential and ATP levels in isolated rat liver mitochondria, and on respiratory chain complex I NADH oxidase activity in submitochondrial particles. Dehydromonocrotaline, but not the parent compound, showed a concentration-dependent inhibition of glutamate/malate-supported state 3 respiration (respiratory chain complex 1), but did not affect succinate-supported respiration (complex II). Only dehydromonocrotaline dissipated mitochondrial membrane potential, depleted ATP, and inhibited complex I NADH oxidase activity (IC50 = 62.06 mu M) through a non-competitive type of inhibition (K-I = 8.1 mu M). Therefore, dehydromonocrotaline is an inhibitor of the activity of respiratory chain complex I NADH oxidase, an action potentially accounting for the well-documented monocrotaline's hepatotoxicity to animals and humans. The mechanism probably involves change of the complex I conformation resulting from modification of cysteine thiol groups by the metabolite. (c) 2007 Elsevier Ltd. All rights reserved.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Peginterferon-alpha plus ribavirin is the most effective therapy for chronic hepatitis C. This study was designed to evaluate the effect of peginterferon alpha-2a (40 kDa) plus ribavirin on sustained virological response (SVR) when administered for 24 vs 48 weeks in genotype 1 naive patients. One hundred and seventeen patients were enrolled in this controlled trial. Genotype 1 patients were randomized to 24 weeks treatment vs 48 weeks treatment. Genotype non-1 patients received 24 weeks treatment as an observational group. Outcomes were SVR (defined by hepatitis C virus-RNA-negative at week 24 of follow-up) and tolerability across the study period. The end-of-treatment response was 59% for genotype 1 (24 weeks treatment), 80% for genotype 1 (48 weeks treatment) and 92% for genotype non-1 (24 weeks treatment). The end-of-follow-up response was 19% (95% confidence interval (CI): 7.2-36.4) (genotype 1, 24 weeks) and 48% (95% CI: 30.2-66.9; P = 0.0175) (genotype 1, 48 weeks). Among genotype non-1, SVR was 76% (95% CI: 62.3-86.5). There were no unexpected adverse events.Almost half of the genotype 1 patients achieved an SVR after 48 weeks treatment with peginterferon alpha-2a (40 kDa) and low-dose ribavirin and confirmed that they should be treated for 48 weeks. Safety profile was acceptable.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The edible parts of cassava cultivar Pioneira roots after 12 and 24 months of cultivation were analysed for human consum. The yield was 63% when the roots were harvested at the right time (12 months), and lower (58%) for older roots, with 24 months. Total cyanide contents were 62,0 - 61,8 and 58,0 - 63,4 ppm, respectively. Cooking time was 13,5 min and 19,5 min, respectively, although the cooked mass quality was similar good. The edible part of the roots was processed in french fries or tholes, submited to two treatment: blanching for three minutes and boiling for ten minutes. Treated and in natura tholes were fried in vegetable oil at 190-degrees-C. The effect of freezing (-20-degrees-C for 60 days) on the cooking quality was also evaluated. The frozen storage reduced the total cyanid content in all treatment. The rate of cyanid decrease were 45%, 84% and 88% with frying, blanching and frying, and boiling and frying, respectively. Blanching followed by frying assured a safe cyanid level for human consum as well as a good acceptance in sensorial analysis. The influence of the age of the roots in cooking quality was a decrease in softness. Frozen storage softened the 24 month old roots and worsened the flavor of 12 month old root. For table purposes cassava roots should be processed in french fries and blanching, what would allow frozen storage of edible part.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Detailed room temperature micro-Raman scattering, X-ray diffraction, atomic force microscopy and specular reflectance infrared Fourier transform spectroscopy studies were carried out on soft chemical by processed Pb1-xBaxTiO3 thin films. The micro-Raman spectra pointed the existence of a stable tetragonal ferroelectric phase in the entire composition range (0 < x <= 1). The infrared reflectance spectra showed that the frequency of several peaks decreases as the Ba2+ concentration increases. These features are correlated to a decrease in the tetragonal distortion of the TiO6 octahedra as the Ba2+ concentration increases. Furthermore, as x increases from 0.70 to 1.0, the Raman spectrum shows an evolution towards the well-known Raman spectrum of the tetragonal BaTiO3. Therefore, we demonstrated that the combination of solid solution PbTiO3-BaTiO3 with a grain size in the order of 30-40 nm supports the tetragonal ferroelectric phase at room temperature. (C) 2007 Elsevier B.V. All rights reserved.