Reciclagem química de Polietileno utilizando Sílica Mesoporosa tipo SBA-15 avalizada por Termogravimetriae Espectrometria de Massas

The chemical recycling of polyolefins has been the focus of increasing attention owing potential application as a fuel and as source chemicals. The use of plastic waste contributes to the solution of pollution problems.The use of catalysts can enhance the thermal degradation of synthetic polymers, which may be avaliated by Themogravimetry (TG) and mass spectrometry (MS) combined techniques. This work aims to propose alternatives to the chemistry recycling of low-density polyethylene (LDPE) on mesoporous silica type SBA-15 and AlSBA-15.The mesoporous materials type SBA-15 and AlSBA-15 were synthesized through the hydrothermal method starting from TEOS, pseudobohemite, cloridric acid HCl and water. As structure template was used Pluronic P123. The syntheses were accomplished during the period of three days. The best calcination conditions for removal of the organic template (P123) were optimized by thermal analysis (TG/DTG) and through analyses of Xray diffraction (XRD), infrared spectroscopy (FT-IR), nitrogen adsorption and scanning electron microscopy (SEM) was verified that as much the hydrothermal synthesis method as the calcination by TG were promising for the production of mesoporous materials with high degree of hexagonal ordination. The general analysis of the method of Analog Scan was performed at 10oC/min to 500 oC to avoid deterioration of capillary with very high temperatures. Thus, with the results, we observed signs mass/charge more evident and, using the MID method, was obtained curve of evolution of these signals. The addition of catalysis produced a decrease in temperature of polymer degradation proportional to the acidity of the catalyst. The results showed that the mesoporous materials contributed to the formation of compounds of lower molecular weight and higher value in the process of catalytic degradation of LDPE, representing an alternative to chemical recycling of solid waste

Serum Iron Parameters and Acute Experimental EHV-1 Infection in Horses

Background Research in humans has demonstrated that high serum iron (sFe) concentration can predispose to infection, and many infections subsequently result in alterations of host sFe. A decrease in sFe concentration is an early and sensitive indicator of systemic inflammation caused by tissue necrosis, bacterial infections, or endotoxemia in horses. Serum iron parameters in acute equine herpesvirus type 1 (EHV-1) infection have not been evaluated previously. Objectives To document the sFe response to EHV-1 infection and to determine whether or not significant differences in sFe concentration exist between EHV-1 infected horses that develop neurologic disease and those that do not. Animals A total of 14 horses experimentally infected with EHV-1. Methods Data were collected as an ancillary data set during a blinded experimental EHV-1 infection. Horses were infected with the rAb4 strain of EHV-1. Temperature, neurologic score, packed cell volume (PCV), and sFe parameters (sFe concentration, % saturation, and total iron-binding capacity) were recorded daily for 2weeks. Data were evaluated using Wilcoxon signed rank tests and Wilcoxon rank sum tests with Bonferroni corrections. Conclusions and Clinical Relevance Serum iron concentration decreases significantly in a biphasic pattern after EHV-1 infection. There was no significant difference in sFe concentration in horses that developed neurologic disease and those that did not in these experimentally infected animals. Serum iron parameters may be useful in monitoring the clinical course of viral infections such as EHV-1.

Fatores genéticos e de meio na produção de leite de caprinos leiteiros

Objetivou-se, no presente estudo, avaliar a produção de leite de caprinos leiteiros da região sudeste do Brasil, com intuito de verificar os fatores de meio e estimar os parâmetros genéticos pelo método dos mínimos quadrados (MMQ). Os controles de 1336 lactações foram inicialmente ajustados pela função multifásica (difásica) e calculou-se a produção de leite total (PLT). Os dados foram provenientes de sete propriedades e três raças (Parda Alpina, Saanen e Toggenburg). A média e o erro-padrão da PLT estimados pelo MMQ foram de 635,31 ±39,75 kg. A interação ano x estação do parto influenciou a PLT. em um dos anos estudados, a PLT foi menor para as cabras paridas no final da estação. Nas três estações de parto, observou-se comportamento quadrático da PLT, em função dos anos de parto. Para as três estações, a PLT aumentou de 1986 até meados de 1990, decrescendo em seguida. A idade de máxima PLT foi observada aos 46,65 meses. Das três raças estudadas, observou-se que as raças Parda Alpina e Saanen apresentaram alternância de superioridade na PLT em algumas fazendas, porém maiores que a Toggenburg. Os coeficientes de herdabilidade e repetibilidade da PLT estimados pelo MMQ foram de 0,296 ± 0,079 e 0,277 ± 0,033, respectivamente. Estes resultados revelam baixa confiabilidade em poucas observações dessas características ou na inconsistência das estimativas da função multifásica. Como a PLT é uma característica limitada ao sexo, sugere-se o teste de progênie como método de seleção mais eficiente para os reprodutores e uso de inseminação artificial como processo de disseminação do material genético selecionado.

Structural, functional, and bioinformatics studies reveal a new snake venom homologue phospholipase A(2) class

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

Hunger suppresses the onset and the freezing component of the antipredator response to conspecific skin extract in pintado catfish

Although the skin of an injured conspecific releases alarm substance in some fish species, it has been shown that such damage induces feeding behaviour rather than an alarm reaction under conditions of food scarcity. We studied chemical communication associated with this paradox in a Brazilian catfish, the pintado (Pseudoplatystoma coruscans). In preliminary tests pintado were confirmed to demonstrate an alarm reaction to conspecific skin extract. In the experiment we investigated whether skin extract of pintado induces either alarm response (panic or alert component) or feeding in hungry conspecifics. Fish feed-deprived for eight days and fed control fish were exposed to either conspecific skin extract or distilled water (as a control). Alarm reaction was restricted to the skin extract treatment and occurred in the fish irrespective of their hunger state, but the components of this response were significantly affected by hungry. Fed fish showed a complete alarm reaction (dashing and freezing behaviours). Feed-deprived fish exhibited only part of this biphasic response, the dashing component. We conclude that chemicals from injured fish elicit an alarm reaction, which is partially inhibited by feeding motivation.

Molecular, kinetic, thermodynamic, and structural analyses of Mycobacterium tuberculosis hisD-encoded metal-dependent dimeric histidinol dehydrogenase (EC 1.1.1.23)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The kinetic mechanism of human uridine phosphorylase 1: Towards the development of enzyme inhibitors for cancer chemotherapy

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Hydrogen/deuterium exchange mass spectrometry for characterizing phosphoenolpyruvate-induced structural transitions in Mycobacterium tuberculosis 5-enolpyruvylshikimate-3-phosphate synthase (EC 2.5.1.1)

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

Production, purification and characterization of a minor form of xylanase from Aspergillus versicolor

A strain of Aspergillus versicolor produces a xylanolytic complex containing two components, the minor component being designated xylanase II. The highest production of xylanase II was observed in cultures grown for 5 days in 1% wheat bran as carbon source, at pH 6.5. Xylanase II was purified 28-fold by DEAE-Sephadex and HPLC GF-5 10 gel filtration. Xylanase II was a monomeric glycoprotein, exhibiting a molecular mass of 32 kDa with 14.1% of carbohydrate content. Optimal pH and temperature values for the enzyme activity were about 6.0-7.0 and 55 degreesC, respectively. Xylanase II thermoinactivation at 50degreesC showed a biphasic curve. The ions Hg2+, Cu2+ and the detergent SDS were strong inhibitors, while Mn2+ ions and dithiothreitol were stimulators of the enzyme activity. The enzyme was specific for xylans, showing higher specific activity on birchwood xylan. The Michaelis-Menten constant (K-m) for birchwood xylan was estimated to be 2.3 mg ml(-1) while maximal velocity (V-max) was 233.1 mumol mg(-1) min(-1) of protein. The hydrolysis of oat spell xylan released only xylooligosaccharides. Published by Elsevier Ltd.

Regulation of breathing and body temperature of a burrowing rodent during hypoxic-hypercapnia

Burrowing mammals usually have low respiratory sensitivity to hypoxia and hypercapnia. However, the interaction between ventilation (V), metabolism and body temperature (Tb) during hypoxic-hypercapnia has never been addressed. We tested the hypothesis that Clyomys bishopi, a burrowing rodent of the Brazilian cerrado, shows a small ventilatory response to hypoxic-hypercapnia, accompanied by a marked drop in Tb and metabolism. V, Tb and O-2 consumption (VO2) of C. bishopi were measured during exposure to air, hypoxia (10% and 7% O-2), hypercapnia (3% and 5% CO2) and hypoxic-hypercapnia (10% O-2 + 3% CO2). Hypoxia of 7% but not 10%, caused a significant increase in V, and a significant drop in Tb. Both hypoxic levels decreased VO2 and 7% O-2 significantly increased V/VO2. Hypercapnia of 5%, but not 3%, elicited a significant increase in V, although no significant change in Tb, VO2 or V/VO2 was detected. A combination of 10% O-2 and 3% CO2 had minor effects on V and Tb, while VO2 decreased and V/VO2 tended to increase. We conclude that C. bishopi has a low sensitivity not only to hypoxia and hypercapnia, but also to hypoxic-hypercapnia, manifested by a biphasic ventilatory response, a drop in metabolism and a tendency to increase V/VO2. The effect of hypoxic-hypercapnia was the summation of the hypoxia and hypercapnia effects, with respiratory responses tending to have hypercapnic patterns while metabolic responses, hypoxic patterns. (C) 2004 Elsevier B.V. All rights reserved.

Habitat Split as a Cause of Local Population Declines of Amphibians with Aquatic Larvae

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

Structural insights into the catalytic mechanism of sphingomyelinases D and evolutionary relationship to glycerophosphodiester phosphodiesterases

Spider venom sphingomyelinases D catalyze the hydrolysis of sphingomyelin via an Mg2+ ion-dependent acid-base catalytic mechanism which involves two histidines. In the crystal structure of the sulfate free enzyme determined at 1.85 angstrom resolution, the metal ion is tetrahedrally coordinated instead of the trigonal-bipyramidal coordination observed in the sulfate bound form. The observed hyperpolarized state of His47 requires a revision of the previously suggested catalytic mechanism. Molecular modeling indicates that the fundamental structural features important for catalysis are fully conserved in both classes of SMases D and that the Class II SMases D contain an additional intra-chain disulphide bridge (Cys53-Cys201). Structural analysis suggests that the highly homologous enzyme from Loxosceles bonetti is unable to hydrolyze sphingomyelin due to the 95G1y -> Asn and 134Pro -> Glu mutations that modify the local charge and hydrophobicity of the interfacial face. Structural and sequence comparisons confirm the evolutionary relationship between sphingomyelinases D and the glicerophosphodiester phosphoesterases which utilize a similar catalytic mechanism. (c) 2006 Elsevier B.V. All rights reserved.

Hydrodechlorination of 1,2-dichloroethane by rhodium catalysts under water gas shift reaction conditions

Homogeneous catalysts prepared from rhodium trichloride in aqueous aromatic amines have been shown to reduce C-CI bonds under mild water gas shift conditions (T=100 degrees C, P-CO = 1.0 atm). In a 4-picoline/water solvent mixture, 1,2-dichloroethane is reduced to ethylene and ethane in yields compatible with the consumption of the reducing agent CO and with the formation of CO2. Variation of the catalyst solutions by using different substituted pyridines shows a pattern of catalytic activity parallel to that reported previously for H-2 production from the shift reaction, There is a moderate dependence of activity on the basicity of the aromatic amine, but a methyl group at the alpha-position exercises a strong negative steric effect. Long term studies show decrease of the activity with the time perhaps due to the build up of chloride in the medium. (C) 1999 Elsevier B.V. B.V. All rights reserved.

Reações de Etanol com CO/H2 na Presença do Sistema Catalítico Ru(acac)3/I-

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

An experimental assessment of landscape configuration effects on frog and toad abundance and diversity in tropical agro-savannah landscapes of southeastern Brazil

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