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Search Results: 1 - 10 of 792158 matches for " M.L.C.P. da;Caetano "
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Preparation and Characterization of Hydrous Zirconium Oxide Formed by Homogeneous Precipitation
Silva, G.L.J.P. da;Silva, M.L.C.P. da;Caetano, Tatiana;
Materials Research , 2002, DOI: 10.1590/S1516-14392002000200011
Abstract: this paper reports on the preparation, characterization and study of the ion exchange behavior of hydrous zirconium oxides formed by homogeneous precipitation from zirconium oxychloride. the precipitants used were obtained by thermal decomposition of urea, sodium nitrite or ammonium carbonate. seven compounds were prepared and characterized by thermal analysis, x-ray diffractometry and by surface area measurements. amorphous forms were obtained in each case, a result that agrees with those obtained by conventional gel precipitation methodology. all these materials present surface area values of >148 m2.g-1, determined after heat treatment at 50 °c. the ion exchange behavior of each hydrous zirconium oxide prepared was studied using k+ as the exchanged species and the results compared with those obtained for hydrous zirconium oxide originally precipitated by the sol gel method.
Preparation and Characterization of Hydrous Zirconium Oxide Formed by Homogeneous Precipitation
Silva G.L.J.P. da,Silva M.L.C.P. da,Caetano Tatiana
Materials Research , 2002,
Abstract: This paper reports on the preparation, characterization and study of the ion exchange behavior of hydrous zirconium oxides formed by homogeneous precipitation from zirconium oxychloride. The precipitants used were obtained by thermal decomposition of urea, sodium nitrite or ammonium carbonate. Seven compounds were prepared and characterized by thermal analysis, X-ray diffractometry and by surface area measurements. Amorphous forms were obtained in each case, a result that agrees with those obtained by conventional gel precipitation methodology. All these materials present surface area values of >148 m2.g-1, determined after heat treatment at 50 °C. The ion exchange behavior of each hydrous zirconium oxide prepared was studied using K+ as the exchanged species and the results compared with those obtained for hydrous zirconium oxide originally precipitated by the sol gel method.
Hydrous Tantalum Phosphates for Ion Exchange Purposes: A Systematic Study
Silva, M.L.C.P.da;Silva, G.L.J.P. da;Villela Filho, D.N.;
Materials Research , 2002, DOI: 10.1590/S1516-14392002000100012
Abstract: this work describes two methods of preparation of hydrous tantalum phosphates and their characterization as ion exchangers. the hydrous metallic phosphate compounds were chemically and physically characterized by thermal gravimetric analysis, x-ray diffractometry and surface area measurements. by the first method, tantalum phosphate was prepared by alkaline fusion of ta2o5 with an excess of k2co3, followed by lixiviation of the tantalate fusion product with hot water, and precipitation with diluted h3po4. preparation ii was performed using metallic ta dissolved in concentrated hf/hno3 acidic mixture followed by hydrolysis of fluortantalic acid intermediary and precipitation with diluted h3po4. both freshly prepared materials (i and ii) were exaustively refluxed with concentrated h3po4, in its boiling point temperature, resulting respectively in ta2o5. 2.1 h2o, (ir) and ta2o5. 1.3 h2o, (iir). characterization of the prepared products have presented the following values: surface area of 108.27 ± 2.80; 220.14 ± 2.67; 117.07 ± 5.25 and 141.61 ± 0.27 m2.g-1 respectively for i, ir, ii and iir. all these materials were amorphous. the ion exchange behavior for all four hydrous tantalum phosphates was studied using na+, k+ and ba+2 as the exchanged species. the values for typical ion exchange capacity were 1.64; 1.23; 1.47 and 1.01 miliequivalent.g-1, respectively for i, ir, ii and iir products.
Hydrous Tantalum Phosphates for Ion Exchange Purposes: A Systematic Study
Silva M.L.C.P.da,Silva G.L.J.P. da,Villela Filho D.N.
Materials Research , 2002,
Abstract: This work describes two methods of preparation of hydrous tantalum phosphates and their characterization as ion exchangers. The hydrous metallic phosphate compounds were chemically and physically characterized by thermal gravimetric analysis, X-ray diffractometry and surface area measurements. By the first method, tantalum phosphate was prepared by alkaline fusion of Ta2O5 with an excess of K2CO3, followed by lixiviation of the tantalate fusion product with hot water, and precipitation with diluted H3PO4. Preparation II was performed using metallic Ta dissolved in concentrated HF/HNO3 acidic mixture followed by hydrolysis of fluortantalic acid intermediary and precipitation with diluted H3PO4. Both freshly prepared materials (I and II) were exaustively refluxed with concentrated H3PO4, in its boiling point temperature, resulting respectively in Ta2O5. 2.1 H2O, (IR) and Ta2O5. 1.3 H2O, (IIR). Characterization of the prepared products have presented the following values: surface area of 108.27 ± 2.80; 220.14 ± 2.67; 117.07 ± 5.25 and 141.61 ± 0.27 m2.g-1 respectively for I, IR, II and IIR. All these materials were amorphous. The ion exchange behavior for all four hydrous tantalum phosphates was studied using Na+, K+ and Ba+2 as the exchanged species. The values for typical ion exchange capacity were 1.64; 1.23; 1.47 and 1.01 miliequivalent.g-1, respectively for I, IR, II and IIR products.
Evaluation of inorganic matrixes as supports for immobilization of microbial lipase
Castro, H.F.;Silva, M.L.C.P.;Silva, G.L.J.P;
Brazilian Journal of Chemical Engineering , 2000, DOI: 10.1590/S0104-66322000000400048
Abstract: candida rugosa was immobilized by physical adsorption on several inorganic supports using hexane as coupling medium. the enzymatic activities of the different derivatives were determined by both hydrolysis of olive oil and esterification of n-butanol with butyric acid. the results were compared to previous data obtained by using a controlled porous silica matrix. the goal was to contribute in searching inexpensive supports for optimum lipase performance. all supports examined exhibited good properties for binding the enzyme lipase. zirconium phosphate was the best support, giving the highest percentage of protein fixation (86%) and the highest retention of lipase activity after immobilization (34%). the operational stability performance for niobium oxide derivative was improved by previously activated the support with silane and glutaraldehyde. thermal stabilities were also examined by thermal gravimetric analysis (tg).
Evaluation of inorganic matrixes as supports for immobilization of microbial lipase
Castro H.F.,Silva M.L.C.P.,Silva G.L.J.P
Brazilian Journal of Chemical Engineering , 2000,
Abstract: Candida rugosa was immobilized by physical adsorption on several inorganic supports using hexane as coupling medium. The enzymatic activities of the different derivatives were determined by both hydrolysis of olive oil and esterification of n-butanol with butyric acid. The results were compared to previous data obtained by using a controlled porous silica matrix. The goal was to contribute in searching inexpensive supports for optimum lipase performance. All supports examined exhibited good properties for binding the enzyme lipase. Zirconium phosphate was the best support, giving the highest percentage of protein fixation (86%) and the highest retention of lipase activity after immobilization (34%). The operational stability performance for niobium oxide derivative was improved by previously activated the support with silane and glutaraldehyde. Thermal stabilities were also examined by thermal gravimetric analysis (TG).
Capilaroscopia panoramica periungueal e sua aplica o em doen as reumáticas
Silva L.S.M. da,Lima A.R.A.G.,Pucinelli M.L.C.,Atra E.
Revista da Associa??o Médica Brasileira , 1997,
Abstract:
Varia??o dos componentes da produ??o de dois cultivares de soja, UFV-1 e IAC-7, em fun??o da época de semeadura
Nogueira, S.S.S.;Haag, H.P.;Carelli, M.L.C.;Fahl, J.L.;Maeda, J.A.;
Anais da Escola Superior de Agricultura Luiz de Queiroz , 1984, DOI: 10.1590/S0071-12761984000100008
Abstract: a study was made on early, normal and delayed planting dates on the seed yield and its components of two late varieties of soybean, ufv-1 and iac-7. the field experiment was carried out at campinas experimental station in eutrophic latossolo roxo during the years 1979/80 and 1980/81. in the first year planting were made every twenty days starting from october 5 and in the second year every thirty days starting from september 17, the total being eight and seven in the consecutive years. the parameters studied were: seed yield, nodes/ /plant, podes/plant and seed weight. the planting dates affected the seed yield and its components in both varieties. the number of nodes and pods/plant were more affected than the seed weight. each variety had the same behavior with regard to the number of nodes and pods/plant and the same cannot be said to seed weight. in the first year the seed weight was not affected by the planting date and in the second, late plantings decreased the values of this parameter. the variability of yield components was more effective for highest yields planting dates. number of nodes and pods/plant exercised a greater influence on the seed yield than the seed weight.
Níveis de carnitina na ra??o no desempenho corporal de tricogáster léri (Trichogaster leeri bleeker, 1852)
Tonini, W.C.T.;Mendon?a, P.P.;Polese, M.F.;Abreu, M.L.C.;Matos, D.C.;Vidal Jr., M.V.;Andrade, D.R.;
Arquivo Brasileiro de Medicina Veterinária e Zootecnia , 2011, DOI: 10.1590/S0102-09352011000600033
Abstract: the effects of carnitine were evaluated in diets fed to trichogaster leeri, initial weight 0.5±0.2g and individually randomized into plastic containers (1000ml), with total renewal of water every 48 hours. five isocaloric diets containing 28% crude protein and 3100 kcalof gross energy were made with the supplementation of: t1= 0 mg; t2= 300mg;t3= 600mg; t4= 900mg; and t5= 1200mg of l-carnitina/kg feed. the diets were administered three times daily ad libitum for 45 days. total and standard length, height, weight and size of the tail end, in addition to weight gain, feed conversion ratio and condition factor were evaluated. in all parameters examined the treatment of 900 mg of carnitine/kg was the most efficient on the performance for the t. leeri, and after calculating the maximum points, a concentration of 1.000mg/kg feed is suggested. there was significant difference in tail length, body height, final weight and condition factors.
Mutation and genomic amplification of the PIK3CA proto-oncogene in pituitary adenomas
Murat, C.B.;Braga, P.B.S.;Fortes, M.A.H.Z.;Bronstein, M.D.;Corrêa-Giannella, M.L.C.;Giorgi, R.R.;
Brazilian Journal of Medical and Biological Research , 2012, DOI: 10.1590/S0100-879X2012007500115
Abstract: the tumorigenesis of pituitary adenomas is poorly understood. mutations of the pik3ca proto-oncogene, which encodes the p110-α catalytic subunit of pi3k, have been reported in various types of human cancers regarding the role of the gene in cell proliferation and survival through activation of the pi3k/akt signaling pathway. only one chinese study described somatic mutations and amplification of the pik3ca gene in a large series of pituitary adenomas. the aim of the present study was to determine genetic alterations of pik3ca in a second series that consisted of 33 pituitary adenomas of different subtypes diagnosed by immunohistochemistry: 6 adrenocorticotropic hormone-secreting microadenomas, 5 growth hormone-secreting macroadenomas, 7 prolactin-secreting macroadenomas, and 15 nonfunctioning macroadenomas. direct sequencing of exons 9 and 20 assessed by qpcr was employed to investigate the presence of mutations and genomic amplification defined as a copy number ≥4. previously identified pik3ca mutations (exon 20) were detected in four cases (12.1%). interestingly, the chinese study reported mutations only in invasive tumors, while we found a pik3ca mutation in one noninvasive corticotroph microadenoma. pik3ca amplification was observed in 21.2% (7/33) of the cases. this study demonstrates the presence of somatic mutations and amplifications of the pik3ca gene in a second series of pituitary adenomas, corroborating the previously described involvement of the pi3k/akt signaling pathway in the tumorigenic process of this gland.
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