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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Avaliação da atividade citotóxica, clastogênica e genotóxica do composto ditionato de cis-tetraamino(oxalato)rutênio(III) em linfócitos do sangue periférico humano / Evaluation of cytotoxic activity, clastogenic and genotoxic compound ditionato tetraamino cis-(oxalate) ruthenium (III) in human peripheral blood lymphocytes

REZENDE, Manuela da Rocha Matos 24 February 2010 (has links)
Made available in DSpace on 2014-07-29T15:16:29Z (GMT). No. of bitstreams: 1 MANUELA da rocha.pdf: 1137336 bytes, checksum: 8f429c6f06f0af7ebb98f1fc1b0badbe (MD5) Previous issue date: 2010-02-24 / Chemotherapy agents are increasingly being utilized due to their promising effects in cancer treatment. The desired actions of these drugs are obtained at the cost of frequent and severe side effects. It is essential that drugs utilized for cancer treatment are tested in relation to not only their cytotoxic, but also their clastogenic and genotoxic potentials to establish their clinical risk. Thus, there is increased interest in searching for new metallic compounds presenting antitumor activity with therapeutic potential and reduced side effects, such as those containing platinum (Pt), iron (Fe), titanium (Ti), rhodium (Rh), gold (Au) and ruthenium (Ru). In this work, the cytotoxic, clastogenic and genotoxic properties of cis-tetraamine(oxalato)ruthenium(III) dithionite, cis-[Ru(C2O4)(NH3)4]2(S2O6), were evaluated in peripheral human blood lymphocytes in vitro. Mitotic index (MI), chromosomal aberrations (CA) and DNA damage were analyzed by comet assay. The MI values of human peripheral blood lymphocyte cultures treated with 0.0075, 0.075, 0.75 and 7.5 μM cis-[Ru(C2O4)(NH3)4]2(S2O6) were 6.1, 3.9, 3.2 and 0.2%, respectively. The lowest concentration 0.0075 did not show cytotoxic activity compared to negative control. The CA values obtained for the 0.0075, 0.075 and 0.75 μM concentrations presenting low frequency (1.5, 1.6 and 2.3%, respectively) not expressing clastogenic activity compared to negative control and only at the highest concentration 7.5 μM, showed clastogenic activity, predominantly chromatid breaks and gaps. The data obtained by the comet assay, using cis-[Ru(C2O4)(NH3)4]2(S2O6), suggest that this compound does not show genotoxic activity at concentrations lower than 0.0075 μM. The results of these studies show that cis-[Ru(C2O4)(NH3)4]2(S2O6) has no potential cytotoxic, clastogenic and genotoxic in vitro at concentrations less than or equal to 0.0075 μM. / Estudos de citoxicidade e genotoxicidade têm sido realizados para o desenvolvimento de novos agentes anticâncer com maior seletividade e menores efeitos colaterais de agentes antitumorais convencionais. Neste trabalho, foram avaliadas as propriedades citotóxicas, clastogênicas e genotóxicas do composto ditionato de cis-tetraamino(oxalato)rutênio(III), {cis-[Ru(C2O4)(NH3)4]2(S2O6)}, em cultura de linfócitos de sangue periférico humano in vitro. Foram analisados os parâmetros índice mitótico (IM), aberrações cromossômicas (ACs) e danos induzidos no DNA detectados pelo ensaio cometa. O IM de cultura de linfócitos de sangue periférico humano tratados com 0,0075; 0,075; 0,75 e 7,5μM de {cis-[Ru(C2O4)(NH3)4]2(S2O6)} foram 6,1; 3,9; 3,2 e 0,2%, respectivamente. A menor concentração 0,0075 não apresentou atividade citotóxica comparada ao controle negativo. As ACs derivadas das concentrações 0,0075; 0,075 e 0,75, apresentaram frequência de 1,5; 1,6 e 2,3 %, respectivamente, não manifestando atividade clastogênica comparadas ao contole negativo e somente na concentração de 7,5μM, demonstrou atividade clastogênica, predominando quebras e falhas cromatídicas. Os dados obtidos por meio do ensaio cometa, utilizando {cis-[Ru(C2O4)(NH3)4]2(S2O6)}, sugerem que este composto não apresenta atividade genotóxica em concentrações menores que 0,0075 μM. Os resultados desses estudos demonstram que {cis-[Ru(C2O4)(NH3)4]2(S2O6)} não possui potencial citotóxico, clastogênico e genotóxica in vitro em concentrações menor ou igual a 0,0075 μM.
52

S?ntese e caracteriza??o de p?s Ba(x)Sr(1-x)Co0,8Fe0,2O3- atrav?s do m?todo de coprecipita??o via oxalato / Synthesis and Characterization of Powder Ba(x)Sr(1-x)Co0, 8Fe0,2O3- by Oxalate Co-precipitation Method

Passos, Rafael Hernandez Damascena dos 27 December 2012 (has links)
Made available in DSpace on 2015-03-03T15:01:58Z (GMT). No. of bitstreams: 1 RafaelHDP_DISSERT.pdf: 3336439 bytes, checksum: 4e38712624b4415413756d8862553f95 (MD5) Previous issue date: 2012-12-27 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Ceramic powders based on oxides of perovskite-type structure is of fundamental interest nowadays, since they have important ionic-electronic conductivity in the use of materials with technological applications such as gas sensors, oxygen permeation membranes, catalysts and electrolytes for solid oxide fuel cells (SOFC). The main objective of the project is to develop nanostructured ceramic compounds quaternary-based oxide Barium (Br), Strontium (Sr), Cobalt (Co) and Iron (Fe). In this project were synthesized compounds BaxSr(1-x)Co0, 8Fe0,2O3- (x = 0.2, 0.5 and 0.8) through the oxalate co-precipitation method. The synthesized powders were characterized by thermogravimetric analysis and differential thermal analysis (TGADTA), X-ray diffraction (XRD) with the Rietveld refinement using the software MAUD and scanning electron microscopy (SEM). The results showed that the synthesis technique used was suitable for production of nanostructured ceramic solid solutions. The powders obtained had a crystalline phase with perovskite-type structure. The TGA-DTA results showed that the homogeneous phase of interest was obtained temperature above 1034?C. It was also observed that the heating rate of the calcination process did not affect the elimination of impurities present in the ceramic powder. The variation in the addition of barium dopant promoted changes in the average crystallite size in the nanometer range, the composition being BSCF(5582) obtained the lowest value (179.0nm). The results obtained by oxalate co-precipitation method were compared with those synthesis methods in solid state and EDTA-citrate method / P?s cer?micos ? base de ?xidos de estrutura do tipo perovsquita ? de fundamental interesse atualmente, pois apresentam condutividade i?nica e eletr?nica importante na utiliza??o de materiais com aplica??es tecnol?gicas como: sensores de gases, membranas perme?veis ao oxig?nio, catalisadores e eletr?lito para c?lulas a combust?vel de ?xido s?lido . O objetivo principal dessa pesquisa ? desenvolver compostos cer?micos quarten?rios nanoestruturados ? base de ?xidos de B?rio (Br), Estr?ncio (Sr), Cobalto (Co) e Ferro (Fe). Nesse trabalho foram sintetizados compostos de BaxSr(1-x)Co0,8Fe0,2O3-(x = 0,2, 0,5 e 0,8) atrav?s do m?todo de coprecipita??o via oxalato. Os p?s sintetizados foram caracterizados por an?lise termogravim?trica e termodiferencial (TGA-TDA), difra??o de raios X (DRX) com refinamento pelo m?todo de Rietveld atrav?s do software MAUD e microscopia eletr?nica de varredura (MEV). Os resultados obtidos mostraram que a t?cnica de s?ntese utilizada foi satisfat?rio para produ??o de solu??es s?lidas cer?micas nanoestruturadas. Os p?s obtidos apresentaram uma fase cristalina com estrutura do tipo perovsquita. O resultado de TGA-DTA apresentou que a fase homog?nea de interesse foi obtida a temperatura acima de 1034?C. Foi observado tamb?m que a taxa de aquecimento do processo de calcina??o n?o interferiu na elimina??o das impurezas presentes no p? cer?mico. A varia??o na adi??o do dopante b?rio promoveu altera??es no tamanho m?dio de cristalito em escala nanom?trica, sendo a composi??o BSCF(5582) obtido o menor valor (179,0nm). Os resultados obtidos pelo m?todo de coprecipita??o foram comparados com os m?todos de s?ntese em estado s?lido e complexa??o EDTA-citrato

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