970 resultados para AK44-5000


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The failure of facial prostheses is caused by limitations in the properties of existing materials, especially flexibility and durability. Therefore, this study evaluated the marginal deterioration of a silicone used for fabrication of facial prostheses (Silastic MDX4-4210, Dow Corning Corporation, Midland, MI, USA) according to the influence of artificial aging, daily disinfection, and 2 types of pigmentation. Thirty specimens were fabricated and subdivided in 6 groups: without pigmentation, pigmented with make-up powder and iron oxide, and evaluated with and without the action of the disinfectant. Analysis of marginal deterioration was performed on a scanning electron microscope (magnification, ×5000) immediately 6 months and 1 year after fabrication of specimens, following the guidelines of ASTM International. After visual analysis of the photomicrographs, it was noticed that all groups presented marginal deterioration and alterations in surface texture with time. The use of disinfection did not contribute to the marginal deterioration of polymer (silicone), regardless of the pigmentation and artificial aging.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The study of prehistoric artifacts may contribute to understand the development of these artifacts, and also of ergonomics. This study aims to investigate and identify the types of grips of two Brazilian stone tools (scraper / piercer and a slug) approximately 5000 years old through the use of gloves with sensors and contact maps of the hand palm, exploring the best method for research of ergonomics in prehistory. Hence it can contribute to the discussion of a part of the ergonomics’ history that remains underexplored.

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Research on natural products is extremely important either for new compound discovery with possible pharmacology uses or for its impact on economy, which moves millions of dollars for year. Scientific studies related on utilization and characterization of bioactive substances are important due to the fact that many drugs currently used by the population were synthetized from isolated compounds of natural products. Among many medicinal species commonly used, there are that ones from the genus Eugenia, witch belongs to Myrtaceae family. Eugenia is one of the biggest genus from this family and has about 5000 species and Brazil has 400 of them, which are appreciated on gastronomy for its fruits, for example, pitanga (Eugenia uniflora), cherry (Eugenia involucrata), clove (Eugenia caryophyllata) and cagaita (Eugenia dysinterica). Phytochemical studies of plants from this genus report the presence of several secondary metabolites like flavonoids, tannins, coumarins, anthocyanins and more. Eugenia species have important pharmacology activity as antioxidant, hypothermic, antidiarrheal, antihypertensive, antimicrobial and fungicide. Thus, Eugenia is a genus which has species with potencial phytotherapic products

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Geociências e Meio Ambiente - IGCE

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Preservation of rivers and water resources is crucial in most environmental policies and many efforts are made to assess water quality. Environmental monitoring of large river networks are based on measurement stations. Compared to the total length of river networks, their number is often limited and there is a need to extend environmental variables that are measured locally to the whole river network. The objective of this paper is to propose several relevant geostatistical models for river modeling. These models use river distance and are based on two contrasting assumptions about dependency along a river network. Inference using maximum likelihood, model selection criterion and prediction by kriging are then developed. We illustrate our approach on two variables that differ by their distributional and spatial characteristics: summer water temperature and nitrate concentration. The data come from 141 to 187 monitoring stations in a network on a large river located in the Northeast of France that is more than 5000 km long and includes Meuse and Moselle basins. We first evaluated different spatial models and then gave prediction maps and error variance maps for the whole stream network.

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Pós-graduação em Geociências e Meio Ambiente - IGCE

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A high-resolution, multi-proxy record has been used to determine the environmental changes during the Holocene on the southern Brazilian shelf Present oceanographic conditions reveal wind and freshwater input as the determinants of short-term productivity changes in the study area. Magnetic susceptibility and grain-size variations, together with proxies of productivity (organic carbon, carbon accumulation rate, Ba, Sr, and Ca content, Ba/Al, Ba/Ti, and Al/Ti ratios) were analyzed and compared with proxies of redox condition (V/Ti ratio), terrigenous input (Fe/Ca and Ti/Ca ratios), as well as other Element/Ti ratios, to evaluate the paleoceanographic and paleoclimatic changes over the period. The core covers a time interval of about 7650 years, with sedimentation rates varying from 0.025 to 0.250 cm a(-1), which represent time intervals of between 8 and 80 a per sample. There is a clear change in the sedimentation rate at about 2800 B.P. All grain-size and elemental results indicate the occurrence of conspicuous changes between 5200 and 5000 cal. B.P., as well as between 3000 and 2800 cal. B.P. A comparison of the results with the palynological information available from the adjacent continental areas suggests that the sedimentary changes in this last interval may be correlated with the onset of modern climatic conditions in South America, and especially, with the onset of the Plata Plume Water, a water mass that carries cold, less saline waters towards the north. However, minor changes are observed at ca. 1500 B.P. and are correlated with an increase in the atmospheric humidity. Furthermore, a time-series analysis undertaken using several proxies indicated the occurrence of Sub-Milankovitch cycles, which may be compared with those reported worldwide. (C) 2008 Elsevier Ltd and INQUA. All rights reserved.