984 resultados para Catalysis by modified pillared clays
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Background: The relationship between CETP and postprandial hyperlipemia is still unclear. We verified the effects of varying activities of plasma CETP on postprandial lipemia and precocious atherosclerosis in asymptomatic adult women. Methods: Twenty-eight women, selected from a healthy population sample (n = 148) were classified according to three CETP levels, all statistically different: CETP deficiency (CETPd <= 4.5%, n = 8), high activity (CETPi >= 23.8, n = 6) and controls (CTL, CETP >= 4.6% and <= 23.7%, n = 14). After a 12 h fast they underwent an oral fat tolerance test (40 g of fat/m(2) of body surface area) for 8 hours. TG, TG-rich-lipoproteins (TRL), cholesterol and TRL-TG measurements (AUC, AUIC, AR, RR and late peaks) and comparisons were performed on all time points. Lipases and phospholipids transfer protein (PLTP) were determined. Correlation between carotid atherosclerosis (c-IMT) and postprandial parameters was determined. CETP TaqIB and I405V and ApoE-epsilon 3/epsilon 2/epsilon 4 polymorphisms were examined. To elucidate the regulation of increased lipemia in CETPd a multiple linear regression analysis was performed. Results: In the CETPi and CTL groups, CETP activity was respectively 9 and 5.3 higher compared to the CETPd group. Concentrations of all HDL fractions and ApoA-I were higher in the CETPd group and clearance was delayed, as demonstrated by modified lipemia parameters (AUC, AUIC, RR, AR and late peaks and meal response patterns). LPL or HL deficiencies were not observed. No genetic determinants of CETP deficiency or of postprandial lipemia were found. Correlations with c-IMT in the CETPd group indicated postprandial pro-atherogenic associations. In CETPd the regression multivariate analysis (model A) showed that CETP was largely and negatively predicted by VLDL-C lipemia (R(2) = 92%) and much less by TG, LDL-C, ApoAI, phospholipids and non-HDL-C. CETP (model B) influenced mainly the increment in ApoB-100 containing lipoproteins (R(2) = 85% negatively) and phospholipids (R(2) = 13%), at the 6(th)h point. Conclusion: The moderate CETP deficiency phenotype included a paradoxically high HDL-C and its sub fractions (as earlier described), positive associations with c-IMT, a postprandial VLDL-C increment predicting negatively CETP activity and CETP activity regulating inversely the increment in ApoB100-containing lipoproteins. We hypothesize that the enrichment of TG content in triglyceride-rich ApoB-containing lipoproteins and in TG rich remnants increases lipoproteins` competition to active lipolysis sites, reducing their catabolism and resulting on postprandial lipemia with atherogenic consequences.
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Nanosecond laser flash photolysis has been used to investigate injection and back electron transfer from the complex [(Ru-(bpy)(2)(4,4`-(PO(3)H(2))(2)bpy)](2+) surface-bound to TiO(2) (TiO(2)-Ru(II)). The measurements were conducted under conditions appropriate for water oxidation catalysis by known single-site water oxidation catalysts. Systematic variations in average lifetimes for back electron transfer,
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Alternative and clean energy generation research has been intensified in last decades. Among the alternatives, fuel cells are one of the most important. There are different types of fuel cells, among which stands out intermediate temperature solid oxide fuel cell (IT-SOFC) matter of the present work. For application as cathode on this type of devices, the ceramic Ba0.5Sr0.5C0.8Fe0.2O3-δ doped with rare earth ions (Nd, Sm) have been quite promising because they show good ionic conductivity and operate at relatively low temperatures (500 - 800°C). In this work, Ba0.5Sr0.5Co0.8Fe0.2O3-δ, (BaSr)0.5Sm0.5Co0.8Fe0.2O3-δ and (BaSr)0.5Nd0.5C0.8Fe0.2O3-δ were obtained by modified Pechini method, making use of gelatin as polymerizing agent. The powders were characterized by X-Ray Diffraction (XRD), Temperature Programmed Reduction (TPR) and Scanning Electron Microscopy (SEM). The perovskite phase was observed in all X-ray patterns for the materials Ba0.5Sr0.5C0.8Fe0.2O3-δ doped with rare earth ions (Nd, Sm). The SEM images showed that the materials have a characteristics porous, with very uniform pore distribution, which are favorable for application as cathodes. Subsequently, screen-printed assymmetrical cells were studied by impedance spectroscopy, to assess the kinetics of the cathode for the reduction reaction of oxygen. The best resistance to the specific area was found for the cathode BSSCF sintered at 1050 °C for 4 hours with around 0.15 Ω.cm2 at 750 °C as well as cathodes BSNCF and BSCF obtained resistances specific area of 0.2 and 0.73 Ω.cm2, respectively, for the same conditions. The polarization curves showed similar behavior to the best cathodes BSSCF and BSNCF, such combination of properties indicates that the film potentially depict good performance as IT-SOFC cathodes
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Sonicated mixtures of dimethyldioctadecylammonium chloride (DODAC), egg phosphatidylcholine (PC), dimyristoyl phosphatidylcholine (DMPC), and dipalmitoyl phosphatidylcholine (DPPC) were used to analyze vesicle effects on the rate of decarboxylation of 6-nitrobenzisoxazol-3-carboxylic acid (Nboc). Electron microscopic images of the vesicles were obtained with trehalose, a know cryoprotector. Phase diagrams and phase transitions temperatures of the vesicle bilayers were determined. Nboc decarboxylation rates increased in the presence of vesicles prepared with both phospholipids and DODAC/phospholipid mixtures. Quantitative analysis of vesicular effects was done using pseudophase models. Phospholipids catalyzed up to 140-fold while the maximum catalysis by DODAC/lipid vesicles reached 800-fold. Acceleration depends on alkyl chain length, fatty acid insaturation of the lipids, and the DODAC/phospholipid molar ratio. Catalysis is not related to the liquid crystalline-gel state of the bilayer and may be related to the relative position of Nboc with respect to the interface.
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The present work aims the preparation of filmes of strontium-doped lanthanum manganite (perovskita) yttria-stabilized zirconia (LSM-SDC) films deposited on substrate of YSZ by means of spin coating technique having as principal objective their application to solid oxide fuel cells of intermediate temperature. La0,8Sr0,2MnO3 and Ce0,8Sm0,2O1,9 were obtained by modified Pechini method by use of gelatin which act as polymerization agent. The powders obtained were characterized by Xray fluorescence, X ray diffraction, electronic scanning microscopy and the superficial area by BET method. The results obtained by X-ray fluorescence showed that the route adopted for obtention of powders was effective in the obtention of the compositions with close values to the stoichiometrics. Ethyl cellulose was used as pore-forming agent and mixed with the LSM-SDC powders in weight proportions of 1:24, 2:23 and 1:9. The films were sintered at 1150 °C for 4 h and characterized by X-ray diffraction and scanning electron microscopy technique (SEM) and atomic force. The phases quantification of the precursory powders and of the obtained films was carried through Rietveld method. According with the analysis of SEM, as the content of ethyl cellulose was increased, the pore distribution in films become more uniform and the pore size reduced. The methodology used for the obtention of the films was very efficient, considering a material was obtained with characteristics that were proper to the application as electrolyte/cathode system to solid oxide fuel cells
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Two pillaring methods were tested to synthesize pillared clays containing mixed Al/Co pillars. Using the first method, based on the traditional procedure, were obtained materials containing different Co concentrations: 10, 25, 50, 75 and 100 % of Co in the pillaring solution. Just the experiments with low concentrations (10 and 25 % of Co) has formed pillared clays, whereas the sample with 25 % of cobalt showed best results compared with the one obtained just using Al as pillaring agent (basal spacing higher than 18 Å and surface area bigger than 300 m²/g). The 27Al NMR results pointed out the formation of mixed Al/Co pillars due to decreased between the intensities of AlVI/AlIV signals, indicating that the AlIV content decreased while Co content increased, suggesting the isomorphic substitution of Al atoms for Co in the Keggin ion structure (pillaring agent). For the samples containing 75 and 100 % of cobalt, it was verified the formation of others materials, which could be identified as hydrotalcite like compounds. The second pillarization method was named mixed layers, because the objective was to intercalate clay layers with hydrotalcite layers. Thus, after calcination, the hydrotalcite layers would dehydroxylate, resulting just in the metals oxides, intercalated between the clay sheets, thus generating, a pillared clay. For this purpose, were tested 4 synthesis procedures: physical mixture, mixture in water, ionic exchange under reflux and in situ synthesis. Of these, the method which showed the best results was the in situ synthesis, in which basal spacings of 14 Å (after calcination) were obtained, indicating that the samples are intercalated with metal oxides (Mg and Al). This procedure was reproduced with a Co-Al LDH (layered double hydroxide) and similar results were obtained, testifying the method reproducibility
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The frequency of anti-T.gondii IgG antibodies was evaluated and compared in 253 sera samples of equines by modified agglutination test (MAT) and indirect immunofluorescent antibody test (IFAT). Fifteen samples (5.9%) were positive by IFAT and 32 (12.6%) by MAT. Significant difference between the two methods was found when a cutoff titer of 16 was established. There was no correlation with breed, gender, and age of horses examined.
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A toxoplasmose é uma das zoonoses mais difundidas no mundo, causada pelo Toxoplasma gondii, um protozoário parasita intracelular obrigatório. Uma alta porcentagem de animais apresenta anticorpos específicos causados por exposição prévia, levando a uma infecção crônica. Os felídeos são os hospedeiros definitivos e outros animais homeotérmicos, incluindo os primatas, são os hospedeiros intermediários. Este estudo objetivou determinar a prevalência da infecção por T. gondii em macacos-prego (Cebus apella nigritus) de vida livre da Estação Ecológica localizada na Mata de Santa Teresa, Ribeirão Preto, SP, Brasil. Anticorpos anti-T. gondii foram pesquisados pelo método de aglutinação direta modificada (MAT) em amostras de soro de 36 macacos-prego, utilizando-se o título oito como de corte. Dos animais estudados, 3/36 (8,33%; IC95% 3,0-21,9%) apresentaram anticorpos anti-T. gondii, todos com título 32. Nenhuma diferença significativa (P>0,05) foi observada com relação ao sexo (1/3 machos e 2/3 fêmeas), e à idade (1/3 jovens e 2/3 adultos). Assim, estes resultados demonstram alta prevalência de anticorpos anti-T. gondii em primatas no estado de São Paulo.
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Synanthropic rodents, mainly rats and mice, become ecologically associated with men due to changes in their ecosystems caused by human activities. These animals may take part in the epidemiological cycles of several diseases, including toxoplasmosis. The presence of serum antibodies to Toxoplasma gondii in 43 rodents captured in the urban area of Umuarama, PR, Brazil, was verified by modified agglutination test (MAT). Brain and heart samples were also collected and bioassayed in mice for the isolation of the parasite. Isolated samples were analyzed by 12 multilocus genotyping. Although all rodents were seronegative, the parasite was isolated in one mouse (Mus musculus) and one rat (Rattus rattus). Genotyping showed that these samples were similar to those previously isolated from cats in the state of Parana, Brazil. (C) 2010 Elsevier B.V. All rights reserved.
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INTRODUÇÃO: A hemiparesia após o acidente vascular encefálico (AVE) é a sequela mais frequente, prejudicando a velocidade de execução dos movimentos automáticos, diminuindo a autonomia do indivíduo e gerando incapacidade. OBJETIVOS: Analisar o efeito da espasticidade nos padrões lineares de marcha (PLM) em indivíduos hemiparéticos. MÉTODOS: Foram estudados dois grupos: 20 indivíduos com AVE (G1) e 20 indivíduos sadios, destros, sem sequela neurológica (G2), com média de idade de 54,2 e 52,6 anos respectivamente. Foram avaliados os PLM pelo protocolo de Nagazaki, o tônus muscular pela escala de Ashworth modificada e o arco de movimento por goniometria. Foi feita comparação dos parâmetros nos dois grupos pelo teste t de Student e correlação de Spearman com nível de significância de 5%. RESULTADOS: A média da distância foi de 14,52 m e 32,16 m, e o tempo foi de 23,75 s e 19,02 s no G1 e G2 respectivamente (p < 0,0001). Na comparação entre os grupos, a amplitude média de passo e a velocidade média foram estatisticamente significantes (p < 0,05) e a cadência não mostrou significância (p = 0,1936). Quando os PLM foram comparados com o grau de espasticidade dos músculos gastrocnêmio e sóleo, mostraram associação negativa com distância, amplitude de passo e velocidade e associação positiva com o tempo (p < 0,05). CONCLUSÃO: Quanto maior o grau de espasticidade dos músculos gastrocnêmio e sóleo, menores serão os parâmetros lineares de marcha do indivíduo com sequela de hemiparesia pós-AVE.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)