664 resultados para 13077-096
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Objectives. The aim of this study was to evaluate the cytotoxic effect of the monomers isobutyl methacrylate (IBMA) and 1,6-hexanediol dimethacrylate (1,6-HDMA), the plasticizer di-n-butyl phthalate (DBP), and the degradation by-products methacrylic acid (MA) and benzoic acid (BA) on L929 cells. Based on previous investigations on the release of these compounds from hard chairside reline resins, a range of concentrations (mu mol/L) were selected for the cytotoxicity tests (IBMA, 5.491406.57; 1,6-HDMA, 1.2239.32; DBP, 1.12143.8; MA, 9.07581; BA, 3.19409).Methods. Cytotoxic effects were assessed using MTT and 3H-thymidine assays after the cells had been exposed to the test compounds at the given concentrations for 24h. Cytotoxicity was rated based on cell viability relative to controls (cells exposed to medium without test substances).Results. DNA synthesis activity was inhibited by all compounds. Mitochondrial dehydrogenase activity decreased in cells treated with monomers, plasticizer and MA by-product, whereas no cytotoxic effect was observed on contact with BA at the majority of concentrations tested. The ranges of suppression for 3H-thymidine assay were: IBMA, 2595%; 1,6-HDMA, 9598%; DBP, 4098%; MA, 9799%; BA, 5471%. For MTT assay, the ranges of suppression were: IBMA, 096%; 1,6-HDMA, 2689%; DBP, 1780%; MA, 5266%; BA, 027%. The 3H-thymidine assay was more sensitive than the MTT assay.Significance. This study evaluated the cytotoxicity of a wide range of concentrations of monomers (IBMA and 1,6-HDMA), plasticizer (DBP) and degradation by-products (MA and BA), including those expected to be released from hard chairside reline resins. The differences observed in the cytotoxicity of these compounds, along with other properties, may assist the dental practitioners in the selection of reline materials with improved service life performance and low risk of adverse reactions in patients who wear relined dentures.
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FUNDAMENTO: Ausência de estudos na literatura validando equações preditivas da frequência cardíaca máxima (FCmáx) em crianças e adolescentes. OBJETIVO: Analisar a validade das equações preditivas da FCmáx 220 - idade e 208 - (0,7 x idade) em meninos com idades entre 10 e 16 anos. MÉTODOS: Um teste progressivo de esforço máximo foi realizado em 69 meninos com idades entre 10 e 16 anos, aparentemente saudáveis e ativos. A velocidade inicial do teste foi de 9 km/h com incrementos de 1 km/h a cada três minutos. O teste foi mantido até a exaustão voluntária, considerando-se como FCmáx a maior frequência cardíaca atingida durante o teste. A FCmáx medida foi comparada com os valores preditos pelas equações 220 - idade e 208 - (0,7 x idade) através da ANOVA, medidas repetidas. Resultados: Os valores médios da FCmáx (bpm) foram: 200,2 ± 8,0 (medida), 207,4 ± 1,5 (220 - idade) e 199,2 ± 1,1 (208 - (0,7 x idade)). A FCmáx predita pela equação 220 - idade foi significantemente maior (p < 0,001) que a FCmáx medida e que a FCmáx predita pela equação (208 - (0,7 x idade)). A correlação entre a FCmáx medida e a idade não foi estatisticamente significativa (r = 0,096; p > 0,05). CONCLUSÃO: A equação 220 - idade superestimou a FCmáx medida e não se mostrou válida para essa população. A equação 208 - (0,7 x idade) se mostrou válida apresentando resultados bastante próximos da FCmáx medida. Estudos futuros estudos com amostras maiores poderão comprovar se a FCmáx não depende da idade para essa população, situação em que o valor constante de 200 bpm seria mais apropriado para a FCmáx.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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We have measured the Lambda(b) lifetime using the exclusive decay Lambda(b)-> J/psi Lambda, based on 1.2 fb(-1) of data collected with the D0 detector during 2002-2006. From 171 reconstructed Lambda(b) decays, where the J/psi and Lambda are identified via the decays J/psi ->mu(+)mu(-) and Lambda -> p pi, we measured the Lambda(b) lifetime to be tau(Lambda(b))=1.218(-0.115)(+0.130)(stat)+/- 0.042(syst) ps. We also measured the B-0 lifetime in the decay B-0 -> J/psi(mu(+)mu(-))K-S(0)(pi(+)pi(-)) to be tau(B-0)=1.501(-0.074)(+0.078)(stat)+/- 0.050(syst) ps, yielding a lifetime ratio of tau(Lambda(b))/tau(B-0)=0.811(-0.087)(+0.096)(stat)+/- 0.034(syst).
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We consider a model for rattling in single-stage gearbox systems with some backlash consisting of two wheels with a sinusoidal driving; the equations of motions are analytically integrated between two impacts of the gear teeth. Just after each impact, a mapping is used to obtain the dynamical variables. We have observed a rich dynamical behavior in such system, by varying its control parameters, and we focus on intermittent switching between laminar oscillations and chaotic bursting, as well as crises, which are sudden changes in the chaotic behavior. The corresponding transient basins in phase space are found to be riddled-like, with a highly interwoven fractal structure. (C) 2004 Elsevier Ltd. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Com o objetivo de estudar o efeito de herbicidas aplicados em pré e pós-emergência, isolados e em combinações nas épocas seca e úmida, para o controle de melão-de-são-caetano (Momordica charantia) em área de cana-soca, desenvolveu-se um experimento no período de junho de 2007 a julho de 2008, na Fazenda Gabriela, no município de Bebedouro (SP). O delineamento experimental foi o de blocos ao acaso, com quatro repetições, em esquema de parcela subdividida. Nas parcelas foram estudados quatro tratamentos de herbicidas: imazapic (0,147 kg ha-1) e amicarbazone (1,4 kg ha-1), aplicados uma semana após a colheita da cana; clomazone mais hexazinone (0,8 kg ha-1 + 0,2 kg ha-1) e amicarbazone (1,4 kg ha-1), aplicados em agosto, aos 63 dias após a colheita da cana, pulverizados na época seca, além de tratamento sem aplicação. Nas subparcelas foram testadas as aplicações em pós-emergência de quatro tratamentos de herbicidas: mesotrione (0,192 kg ha-1), amicarbazone (1,4 kg ha-1), mesotrione mais amicarbazone (0,096 kg ha-1+ 0,7 kg ha-1) e 2,4-D (1,005 kg ha-1), na época úmida e a manutenção de tratamento sem herbicida. Para o controle de melão-de-são-caetano a aplicação de herbicidas na época úmida (período de chuvas) é obrigatória e desnecessária na época seca. Os herbicidas mesotrione e amicarbazone, isolados ou em mistura, aplicados na época úmida são eficazes no controle em pós-emergência das plantas e na inibição de novos fluxos de emergência de melão-de-são-caetano na época úmida.
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Some individuals of the species Arenaeus cribrarius (Lamarck, 1818) bear a characteristic pink abdomen, which is notably different from the usual white coloration. The incidence of this chromatic alteration was determined for a single population and its relation with other individual variables were examined. The individuals were monthly collected from May, 1991 to April, 1993, in Ubatuba, São Paulo, with the aid of a shrimp fishery boat provided with double-rig trawling nets. All specimens were sexed, measured (CW = carapace width), distributed in 10-mm size classes and classified according to growth phase (juvenile and adult), molting condition and development stage of gonads. The occurrence of pink-colored morphs was also recorded. From a total of 2,096 collected individuals, only 60 females (nine of those ovigerous) presented a pink-colored abdomen, which represents 2.9% of the whole sample and 5.2% of the females. Almost all of them were intermolt individuals (96.6%) and 63.3% showed mature gonads. According to published data, size at the onset of functional maturity in A. cribrarius females is around 60 mm CW, from which the incidence of pink morphs and ovigerous crabs were recorded. The obtained results suggest that such a chromatic alteration is associated to sexual maturity in these females. This characteristic may enhance the attraction potential for mating, shortly after the puberty molt.
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The equilibrium point between blood lactate production and removal (La-min(-)) and the individual anaerobic threshold (IAT) protocols have been used to evaluate exercise. During progressive exercise, blood lactate [La-](b), catecholamine and cortisol concentrations, show exponential increases at upper anaerobic threshold intensities. Since these hormones enhance blood glucose concentrations [Glc](b), this study investigated the [Glc] and [La-](b) responses during incremental tests and the possibility of considering the individual glucose threshold (IGT) and glucose minimum;(Glc(min)) in addition to IAT and La-min(-) in evaluating exercise. A group of 15 male endurance runners ran in four tests on the track 3000 m run (v(3km)); IAT and IGT- 8 x 800 m runs at velocities between 84% and 102% of v(3km); La-min(-) and Glc(min) - after lactic acidosis induced by a 500-m sprint, the subjects ran 8 x 800 m at intensities between 87% and 97% of v(3km); endurance test (ET)- 30 min at the velocity of IAT. Capillary blood (25 mu l) was collected for [La-](b) and [Glc](b) measurements. The TAT and IGT were determined by [La-](b) and [Glc](b) kinetics during the second test. The La-min(-) and Glc(min) were determined considering the lowest [La-] and [Glc](b) during the third test. No differences were observed (P < 0.05) and high correlations were obtained between the velocities at IAT [283 (SD 19) and IGT 281 (SD 21)m. min(-1); r = 0.096; P < 0.001] and between La,, [285 (SD 21)] and Glc(min) [287 (SD 20) m. min(-1) = 0.77; P < 0.05]. During ET, the [La-](b) reached 5.0 (SD 1.1) and 5.3 (SD 1.0) mmol 1(-1) at 20 and 30 min, respectively (P > 0.05). We concluded that for these subjects it was possible to evaluate the aerobic capacity by IGT and Glc(min), as well as by IAT and La-min(-).
DFT study on the water-assisted mechanism for the reaction between VO+ and NH3 to yield VNH+ and H2O
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On the basis of DFT calculations, an understanding on the catalytic effect of water in the dehydration reaction between VO+ and NH3 to yield VNH+ and H2O has been obtained. The Gibbs free energy profiles point out that the global process involves two consecutive hydrogen shifts from the nitrogen to the oxygen atom. The catalytic role is achieved by a water assisted mechanism in which water acts as proton donor and acceptor, via transition structures corresponding to a six-membered rings. The corresponding stationary points lie below both the entrance VO+ + NH3, and VNH+ + H2O, channels. (c) 2006 Elsevier B... All rights reserved.
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We suggest a method for constructing trial eigenfunctions for excited states to be used in the variational method. This method is a generalization of the one that uses a superpotential to obtain the trial functions for the ground state. The construction of an effective hierarchy of Hamiltonians is used to determine excited variational energies. The first four eigenvalues for a quartic double-well potential are calculated for several values of the potential parameter. The results are in very good agreement with the eigenvalues obtained by numerical integration.
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Incluye Bibliografía
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In this paper a new parasitoid Megastigmus Dalman, 1820 (Hymenoptera: Chalcidoidea: Torymidae: Megastigminae) species was described in the subgenus Torymus, associated with the gall-forming Leptocybe invasa Fisher & La Salle (Hymenoptera: Eulophidae) in eucalypt plantations in Brazil.