60 resultados para Impurity contents
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Comparative HPLC-UV and LC-MS/MS studies of impurity profiles of a reference sample (Xenical®, F. Hoffmann-La Roche Ltd., Switzerland) vs. generic (Lipiblock®, EMS-Sigma Pharma, a generic drug) were carried out with ethanol extracts of commercial samples. The generic formulation contained higher levels of common impurities as well as a considerable number of impurities not found in the reference product. The detected impurity profile of Lipiblock® revealed that it most likely is based on fermentation. Since the effect of the impurities is unknown, at this point fully synthetic Xenical® appears to offer a better safety margin than Lipiblock® which, however, compares quite well to other generic formulations.
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Relief is regarded as the abiotic factor most strongly influencing pedogenic processes at a local scale. The spatial correlations between the composition of the clay fraction (iron - Fe and aluminum - Al oxides, kaolinite and organic matter - OM) and contents of available phosphorus (P) of an Oxisol were evaluated at hillslope scale under sugarcane cultivation. A total of 119 samples were collected at intersection points on a 100. ×. 100. m georeferenced grid of regularly spaced points 10. m apart in the 0.2-0.4. m depth in an area consisting of two landform components namely: component I (an area with a linear hillslope curvature), and component II (one with a concave-convex hillslope curvature). Soil OM and available P contents were subjected to descriptive statistics and geostatistical analyses in order to assess their variability and spatial dependence. All attributes studied were spatially dependent. Available phosphorus had positive spatial correlation with high crystalline goethite, hematite and gibbsite. Identifying small hillslope curvatures is useful with a view to better understanding their relationships with soil organic matter and available phosphorus, as well as kaolinite and Fe and Al oxide attributes. A simple correlation analysis by itself is inadequate to relate attributes, which requires a supplemental, geostatistical technique. © 2012 Elsevier B.V..
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Annona crassiflora Mart. is a typical fruit of the Brazilian cerrado, considered to be a species of economic interest, mainly for its use in cooking, which is widespread among the inhabitants of that region, and can be found in many typical local dishes, especially sweets, jellies, liqueurs, soft drinks, ice creams and juices. Thus, the objective of this study was to determine the bioactive substance contents and the antioxidant capacity of the lipid fraction of A. crassiflora Mart. seeds in the interest of better identifying the quality of this raw material from the Brazilian cerrado. After the receipt of the fruits, the seeds were removed manually and, then, the lipid fraction was obtained by cold extraction with chloroform:methanol:water (2:1:0.8, v/v/v) and analyzed for the composition of phytosterols, tocopherols, fatty acids, total carotenoids, antioxidant activity and oxidative stability index. The lipid fraction showed significant quantity of bioactive substances, especially phytosterols, tocopherols and unsaturated fatty acids, as well as significant antioxidant capacity and oxidative stability, influenced by the content of phytosterols and the composition of fatty acids present in the analyzed fraction. © 2012 Elsevier B.V.
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The recalcitrance in grasses varies according to cell type and maturation. The origin of the recalcitrance in different regions from sugar cane internodes with varied lignin contents was evaluated. The efficiency of enzymatic hydrolysis was correlated with the chemical, micromorphological and microspectrophotometric characteristics of the samples. The internodes of three sugar cane hybrids were dissected into four different fractions. The outermost fraction and the rind were the most recalcitrant regions, whereas the pith-rind interface and the pith were less recalcitrant. Cellulose conversion reached 86% after 72h of enzymatic digestion of the pith from the hybrid with the lowest lignin content. There was an inversely proportional correlation between the area occupied by vascular bundles and the efficiency of cellulose hydrolysis. High cellulose and low lignin or hemicellulose contents enhanced the efficiency of enzymatic hydrolysis of the polysaccharides. The critical evaluation of the results permitted to propose an empirical parameter for predicting cellulose conversion levels that accounts for the positive effect of high cellulose and low lignin plus hemicellulose and the detrimental effect of abundant vascular bundles. The cellulose conversion levels fit well to this calculated parameter, following a second order polynomial with an r2 value of 0.96. © 2013 Elsevier B.V.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The objective of this work was to evaluate the chemical composition and fatty acid contents of Amazonian and giant river prawns. After four-month farming, with the same diet for both species, palmitic and stearic acids were the main saturated fatty acids. Oleic acid was the main monounsatured fatty acid, and the eicosapentaenoic and docosahexaenoic acids were the most abundant polyunsaturated acids. Amazonian prawn has higher levels of protein and polyunsaturated fatty acids than those of the giant river prawn, which shows its potential for aquaculture.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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There are cassava varieties that present compounds as carotenoids, beta-carotene, lycopene and minerals important for human and animal health. The present study evaluated the antioxidant activity of the white, yellow and pinkish varieties of Manihot esculenta, by mean of the DPPH test and by the ferrous ion-chelating activity. Furthermore, the total phenols, carotenoids, beta-carotene, lycopene and zinc contents were also determined. Utilizing the DPPH test it was possible to find that extracts of boiled samples presented higher antioxidant activity (89.53% -pinkish) in comparison to the fresh samples (1.97% -white). For the ferrous ion-chelating test, the highest activity was found for the boiled pinkish variety extract (63.43%) and the lowest was for fresh yellow extract (17.34%) the white sample did not present activity. The highest concentration of total phenols and zinc content was obtained for the boiled pinkish variety extract 136.12 mg EAG/g of extract and 0,811ppm, respectively, in the concentration of 1000 mu g/mL. The pinkish variety presented also higher quantity of pigments, including carotenoid (29.40 mu g/g), beta-carotene (9.14 mu g/100g) and lycopene (68.92%). According to the results obtained in this study it was possible to conclude that the yellow and pinkish varieties of M. esculenta present quantity of phenolic compounds and minerals sufficient to attribute the antioxidant activity and may thus contribute to reduce oxidative damage and be used as nutraceuticals or directly ingested in the diet to maintain good health.
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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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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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Soils of the Brazilian Cerrado biome have been found to be deficient in copper (Cu) and zinc (Zn). In this area, an Oxisol was deeply excavated in 1962 during the construction of a hydroelectrical plant, and the exposed saprolite material was abandoned, without any reclamation measures. The abandoned land was a harsh environment for plant growth, and the secondary vegetation has not recovered. A field trial was established in 1992 to assess the effects of different grass species and lime amendments on soil reclamation at the degraded site. In 2011 soil samples were collected at three depths (0-10, 10-20, and 20-40cm) from vegetated and bare plots over tilled saprolite, from an untreated area of the saprolite, and from an Oxisol under native forest, used as external reference. Nineteen years after the reclamation effort was begun, the organic carbon (OC) content of the restored saprolite still was much lower than that of the Oxisol under natural vegetation. The undisturbed Oxisol was deficient in extractable Cu (0.16-0.10mgkg(-1)) and Zn (0.10-0.02mgkg(-1)) and exhibited rather low concentrations of extractable iron (Fe; 5.24-1.47mgkg(-1)) and manganese (Mn; 3.21-0.77mgkg(-1)). However, the saprolite under reclamation showed even lower levels of these elements compared to the native forest soil. In the natural soil, OC, N, extractable Fe, Mn, and Cu showed stratification, but this was not the case for extractable Zn. Although the reclaimed saprolite still was far from predisturbance conditions, the revegetation treatments promoted recovery of OC, N, Fe, Mn, and Cu at the surface layers, which resulted in incipient stratification. Extractable Fe, Mn, and Cu were correlated to OC, whereas no association between Zn and OC was detected. Our results also suggest that reclamation of the excavated saprolite may be constrained by micronutrient deficiencies and mostly by the extremely low levels of Zn and Cu.
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The numerical renormalization-group method was originally developed to calculate the thermodynamical properties of impurity Hamiltonians. A recently proposed generalization capable of computing dynamical properties is discussed. As illustrative applications, essentially exact results for the impurity specttral densities of the spin-degenerate Anderson model and of a model for electronic tunneling between two centers in a metal are presented. © 1991.