178 resultados para Barium orthosilicate
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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This experiment aim was to evaluate the contamination of the trace elements (TE) arsenic, barium, cadmium, chromium, copper, mercury, molybdenum, nickel, lead, selenium, and zinc considered in the CONAMA resolution 375 after 13 years long using sewage sludge (SS) as fertilizer in two soils: an Eutroferric Clayed Red Latosol (Rhodic Eutrudox - RE) and a Dystrophic Red Latosol (Typic Haplorthox - TH). Experiment in the field under maize cultivation had four treatments (0, 5, 10, and 20 t of SS ha(-1), dry weight), five replications and an experimental design in randomized blocks. The agrochemicals (dolomitic limestone, single superphosphate, and potassium chloride), SS, soils, and the certified reference materials were digested according to the USEPA 3051A method and the chemical elements were quantified by ICP OES. The TE contents found in the agrochemicals used should not cause immediate environmental impact. The higher TE values were found in the RE and they did not reach the agricultural (more stringent) Investigation Level (IL) yet, according to 420 CONAMA resolution. Persisting the actual SS fertilization amount applied in the soil and the TE concentration in the SS is foreseen that Ba, Cd, Cr, Cu, Ni, and Zn will be the first elements to reach the IL in the RE.
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The aim of this study was to evaluate the rat subcutaneous tissue reaction to calcium hydroxide-based intracanal medicaments, UltraCal XS (calcium hydroxide, barium sulphate, aqueous matrix), Hydropast (calcium hydroxide, barium sulphate, and propyleneglycol), and Calen (Calcium hydroxide, zinc oxide, colophony, and polyethyleneglycol), used as a control. Methods. Forty-eight rats (Rattus Norvegicus Holtzman) were distributed in three groups: Calen, UltraCal XS, and Hydropast. Polyethylene tubes filled with one of the medicaments were implanted in the dorsal subcutaneous. After 7 and 30 days, the implants were removed and the specimens were fixed and embedded in paraffin. Morphological and quantitative analyses were carried out in the HE-stained sections. The numerical density of inflammatory cells in the capsule was evaluated and statistical analyses were performed (P>/0.05). Results. At 7 days, all materials induced an inflammatory reaction in the subcutaneous tissue adjacent to the implants. In all groups, a significant reduction in the number of inflammatory cells and giant cells was verified in the period of 30 days. Conclusion. These results indicate that the calcium hydroxide-based medicaments evaluated present biocompatibility similar to Calen.
Análise físico-química do MTA e do cimento Portland associado a quatro diferentes radiopacificadores
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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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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1. The development of genital organs of rats chronically treated with cimetidine showed that the drug may present anti-androgenic activity. 2. This treatment did not alter the sensitivity of vas deferens to noradrenaline, but increased their sensitivity to BaCl2. 3. In the male reproductive system, cimetidine must have peripheral actions apart from the central ones observed after chronic treatment.
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Ferroelectric strontium barium niobate solid solutions had received great attention due to their excellent pyroelectric, electrooptic and photorefractive properties. Furthermore, they usually also present very interesting phase transition characteristics. In this work, polycrystalline single phase Sr 0.75 Ba 0.25 Nb 2 O 6 thin films were prepared by a hybrid chemical method and deposited on Pt/Ti/SiO 2 /Si substrates. The temperature dependence of dielectric constant was measured at different frequencies and bias field levels. The presence of two dielectric dispersion regions with relaxor characteristics was observed at distinct temperature ranges, corresponding to the ferro-paraelectric and to a structural phase transition at low temperatures, respectively. A specific dielectric dispersion region, associated with an incommensurate superstructure frequently observed in bulk samples, was not observed in this films probably due to their small grain sizes. © 2002 Taylor & Francis.
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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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Pós-graduação em Ciência e Tecnologia de Materiais - FC
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)