1000 resultados para Temperatura de transição.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Trabalho trata da síntese e caracterização de quelatos inéditos de prata, paládio e platina contendo proteínas hidrolisadas da clara de ovo. A ideia consiste em preparar e utilizar quelatos metálicos contendo ligantes de origem natural, como metalofármacos. A pesquisa realizada pode ser dividida em três etapas. A primeira, referente à hidrólise e análise do hidrolisado proteico da clara de ovo. Diversos métodos e condições experimentais foram testadas a fim de se encontrar as condições de hidrólise mais adequadas (natureza da enzima, tempo, pH, temperatura, relação enzima:substrato) para a obtenção de aminoácidos livres e/ou pequenos peptídeos. A segunda parte consistiu na obtenção de compostos de coordenação de platina, prata e paládio contendo o hidrolisado proteico. Nessa etapa, diferentes rotas sintéticas e condições experimentais também foram utilizadas. Além disso, a espectroscopia vibracional no infravermelho foi utilizada nessa etapa para investigar as características estruturais (particularmente, os grupos funcionais presentes) dos compostos metálicos obtidos bem como da matéria prima utilizada (clara de ovo). Após inúmeras tentativas de síntese, três amostras promissoras, do ponto de vista da Química de Coordenação, foram obtidas, a saber, CO-Pd2, CO-Pd9 e CO-Ag3. Ensaios biológicos preliminares, que consistiu na terceira e última parte deste trabalho, foram realizados no sentido de avaliar a capacidade inibitória de crescimento das bactérias S. aureus e E. coli, através da determinação da Concentração Inibitória Mínima (CIM) dos compostos metálicos obtidos.
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Pós-graduação em Ciências Biológicas (Microbiologia Aplicada) - IBRC
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Pós-graduação em Ciências Biológicas (Microbiologia Aplicada) - IBRC
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The mantle transition zone is defined by two seismic discontinuities, nominally at 410 and 660 km depth, which result from transformations in the mineral olivine. The topography of these discontinuities provides information about lateral temperature changes in the transition zone. In this work, P-to-S conversions from teleseismic events recorded at 32 broadband stations in the Borborema Province were used to determine the transition zone thickness beneath this region and to investigate whether there are lateral temperature changes within this depth range. For this analysis, stacking and migration of receiver functions was performed. In the Borborema Province, geophysical studies have revealed a geoid anomaly which could reflect the presence of a thermal anomaly related to the origin of intraplate volcanism and uplift that marked the evolution of the Province in the Cenozoic. Several models have been proposed to explain these phenomena, which include those invoking the presence of a deep-seated mantle plume and those invoking shallower sources, such as small-scale convection cells. The results of this work show that no thermal anomalies are present at transition zone depths, as significant variations in the transition zone thickness were not observed. However, regions of depressed topography for both discontinuities (410 and 660 km) that approximately overlap in space were identified, suggesting that lower-thanaverage, lateral variations in seismic velocity above 410 km depth may exist below the the Borborema Province. This is consistent with the presence of a thermally-induced, low-density body independently inferred from analysis of geoid anomalies. Therefore, the magma source responsible for the Cenozoic intraplate volcanism and related uplift in the Province, is likely to be confined above the upper mantle transition zone.
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Glass-ceramics are prepared by controlled separation of crystal phases in glasses, leading to uniform and dense grain structures. On the other hand, chemical leaching of soluble crystal phases yields porous glass-ceramics with important applications. Here, glass/ceramic interfaces of niobo-, vanado- and titano-phosphate glasses were studied by micro-Raman spectroscopy, whose spatial resolution revealed the multiphase structures. Phase-separation mechanisms were also determined by this technique, revealing that interface composition remained unchanged as the crystallization front advanced for niobo- and vanadophosphate glasses (interface-controlled crystallization). For titanophosphate glasses, phase composition changed continuously with time up to the equilibrium composition, indicating a spinodal-type phase separation.
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High-temperature liquid chromatography (HTLC) is a technique that presents a series of advantages in liquid phase separations, such as: reduced analysis time, reduced pressure drop, reduced asymmetry factors, modified retentions, controlled selectivities, better efficiencies and improved detectivities, as well as permitting green chromatography. The practical limitations that relate to instrumentation and to stationary phase instability are being resolved and this technique is now ready to be applied for routine determinations.
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Inulin is a functional food ingredient, generally employed as sugar or fat substitute in food systems. This ingredient can be found in several vegetal products, including chicory roots. As the solubility of inulin is susceptible to temperature changes, the product suffers a fractionalization resulting in two phases when cooled, originating a precipitated phase, more viscose, and a liquid phase, of lesser viscosity. The study of rheological properties of different phases of inulin extract is important for equipment designing, such as mixer and bombs. In this work, rheological behavior at three different temperatures (25; 40 and 50 ºC) was determined for liquid and precipitated phases of inulin liquid extract, extracted from chicory roots by hot water diffusion and cooled at two different temperatures (8 and -10 ºC), suffering phases separation. The precipitated phase was analyzed in two conditions: pure and with the addition of microencapsulating agents (maltodextrin and hydrolized starch). All of them presented a linear behavior, similar to that of the Plastics of Bingham. Some of them, however, were not an adequate fit to this model.
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This research studied the effect of low density polyethylene packaging and storage temperature on the preservation of fresh-cut (minimally processed) cabbage. The cabbages, previously cooled to a temperature of 10 ºC, were selected, washed, cut in four parts (with the central stalk removed), sanitized, cut in strips, rinsed, put in the centrifuge, weighed and stored in plastic packaging of low density polyethylene (70 µm), and then stored in cold chambers at temperatures of 1 and 10 ºC for 20 days. The following aspects were evaluated: carbon dioxide, oxygen and ethylene in the internal atmosphere of the package as well as, pH, titratable acidity, total soluble solids, vitamin C, loss of fresh mass and the total soluble solids/acidity in the fresh-cut cabbage ratio. The experimental design was entirely casual, with three repetitions. The analysis parameters, except for the vitamin C, loss of fresh mass and ethylene, presented significant variation between the temperatures and days of storage. The cabbage stored at a temperature of 1 ºC presented a shelf life of around 15 days, significantly higher than that stored at 10 ºC. At this temperature, on the 8th day of storage, the product was completely decayed, unfit for commercialization or consumption.
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Behavioral adjustments may occur fast and with less cost than the physiological adaptations. Considering the social behavior is suggestive that the frequency and the intensity of aggressive interactions, the total social cohesion and the extent of vicious attitudes may be used to evaluate welfare. This research presents an analysis of the interactions between the experimental factors such as temperature, genetic and time of the day in the behavior of female broiler breeders under controlled environment in a climatic chamber in order to enhance the different reaction of the birds facing distinct environmental conditions. The results showed significant differences between the behaviors expressed by the studied genetics presenting the need of monitoring them in real-time in order to predict their welfare in commercial housing, due to the complexity of the environmental variables that interfere in the well being process. The research also concluded that the welfare evaluation of female broiler breeders needs to consider the time of the day during the observation of the behaviors.
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In order to determine the energy needed to artificially dry an agricultural product the latent heat of vaporization of moisture in the product, H, must be known. Generally, the expressions for H reported in the literature are of the form H = h(T)f(M), where h(T) is the latent heat of vaporization of free water, and f(M) is a function of the equilibrium moisture content, M, which is a simplification. In this article, a more general expression for the latent heat of vaporization, namely H = g(M,T), is used to determine H for cowpea, always-green variety. For this purpose, a computer program was developed which automatically fits about 500 functions, with one or two independent variables, imbedded in its library to experimental data. The program uses nonlinear regression, and classifies the best functions according to the least reduced chi-squared. A set of executed statistical tests shows that the generalized expression for H used in this work produces better results of H for cowpea than other equations found in literature.
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Kohleria eriantha (Benth.) Hanst is a plant belonging to the family Gesneriaceae, with an underground organ, which is associated with vegetative reproduction. This organ is a rhizome, whose stem bears buds covered with modified leaves that store up starch. In small sections of this rhizome, containing six buds (1.5 to 2.0cm long), only one bud sprouted. The sprouted bud could be differentiated into two morphological pattern: aerial part or rhizome. Sprouting of the rhizome pattern occurred in sections kept on substrate with low water content (1mL of water), or lacking water, whereas sprouting of the aerial part pattern occurred in sections on substrate with high water content (12mL of water). Temperature at 20ºC also stimulated sprouting of the rhizome pattern, regardless of the water volume in the substrate. Sprouting of the rhizome pattern occurred still in sections on substrate to which polyethylene glycol 6000 (PEG) solution was added at the concentrations of 161.2, 235.2 and 340.0g/L, resulting in potentials of -3, -6 and -12 MPa, respectively. Sections kept on substrate with low water content (1 ml of water) showed a reduction in the dry matter content and high osmotic concentration in comparison with those on substrate with high water content. The results obtained revealed that forming of the rhizome pattern was influenced by water content and temperature. It is suggested that sprouting of the rhizome pattern was induced by the low water potential in the sections, when kept on substrate with low water content. Moreover, it was observed that the rhizome buds of Kohleria eriantha showed a high degree of plasticity.
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BACKGROUND: Changes in heart rate during rest-exercise transition can be characterized by the application of mathematical calculations, such as deltas 0-10 and 0-30 seconds to infer on the parasympathetic nervous system and linear regression and delta applied to data range from 60 to 240 seconds to infer on the sympathetic nervous system. The objective of this study was to test the hypothesis that young and middle-aged subjects have different heart rate responses in exercise of moderate and intense intensity, with different mathematical calculations. METHODS: Seven middle-aged men and ten young men apparently healthy were subject to constant load tests (intense and moderate) in cycle ergometer. The heart rate data were submitted to analysis of deltas (0-10, 0-30 and 60-240 seconds) and simple linear regression (60-240 seconds). The parameters obtained from simple linear regression analysis were: intercept and slope angle. We used the Shapiro-Wilk test to check the distribution of data and the t test for unpaired comparisons between groups. The level of statistical significance was 5%. RESULTS: The value of the intercept and delta 0-10 seconds was lower in middle age in two loads tested and the inclination angle was lower in moderate exercise in middle age. CONCLUSION: The young subjects present greater magnitude of vagal withdrawal in the initial stage of the HR response during constant load exercise and higher speed of adjustment of sympathetic response in moderate exercise.
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Universidade Estadual de Campinas. Faculdade de Educação Física
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Universidade Estadual de Campinas . Faculdade de Educação Física