Emplacement setting of the granite sheeted pluton of Esperanca (Brasiliano orogen, Northeastern Brazil)

Anisotropy of magnetic susceptibility (AMS) and isotopic (U-Pb, Sm-Nd) data were combined to study the emplacement setting of the granite sheets that constitute the Esperanca pluton in the Borborema Province (Northeastern Brazil). The sheets dip moderately to the SE along the contact zone between the Paleoproterozoic basement rocks and Early Neoproterozoic orthogneisses and metasediments. Granite fabrics were determined mainly using AMS in 136 sites distributed within the central and western part of the pluton. The sheets normally have susceptibility lower than 0.35 mSI but, locally, where a Ti-poor magnetite appears with titanite, the susceptibility increases up to 5 mSI. Comparison between the silicate fabric and AMS showed inconsistencies between the shape of mineral and magnetic ellipsoids despite of their orientations that fit fairly well to each other. AMS indicated the deformation was partitioned between the lower (tonalite, syenogranite) and upper (leucogranite and coarse porphyritic granite) sheets. In the lower sheets the curvilinear lineation trajectory is attributed to a dominant heterogeneous pure shear event that flattened laterally the still molten tonalite and syenogranite into the regional foliation. ne associated microstructures are typically magmatic. Zircon U/Pb data of the syenogranite yielded a crystallization age of 592 +/- 5 Ma. In the upper sheets the fabric recorded a component of simple shear deformation that displaced the coarse porphyritic granite and the top gneissic host rocks to the southwest. Microstructures are mostly of post-full crystallization type. T(DM) model ages and epsilon(Nd) (t = 0) values indicate that the magma contaminated by partial melting of the regional host rocks. Sheet propagation at the emplacement level would have exploited the contact zone between crustal blocks of different rheologies when the melt pressures would be able to tensionally fail the anisotropy of the host rocks. (C) 2004 Elsevier B.V. All rights reserved.

Yellow ZnxNi1-xWO4 pigments obtained using a polymeric precursor method

New tungstate-based ceramic pigments, displaying ZnxNi1-xWO4 stoichiometry, were obtained at low temperature using a polymeric precursor method. The powder precursors were milled in an attritor mill in an alcoholic rnedium and heat treated for 12 h. yielding homogeneous and crystalline powder pigments. Characterization (TG/DTA, XRD, IR and colorimetry) showed that mass loss increased with increasing Zn contents. Despite the presence of secondary phases and impurities, the wolframite phase was present in all samples. IR analysis revealed bands related to Me-O and [WO6](6-) group stretching was observed. The intensity of the yellow color of the pigments increased with increasing amount of nickel. (c) 2007 Elsevier Ltd. All fights reserved.

Atividade microbiana em solos, influenciada por resíduos de algodão e torta de mamona

Microbial activity constitutes a good indicator of soil quality, and is influenced by the addition of carbon in the system serving as a substrate for microorganisms that increase their activity and release of CO2, comprising the edaphic respiration of the soil. The objective of this study was to evaluate the microbial activity in different soil types with the addition of cake press of castor bean and cotton textile residue. The study was conducted in a greenhouse at the headquarters of Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) Cotton in randomized block design in 4 x 3 factorial arrangement with four replications. At predetermined intervals of 4 days, the containers were opened and the solution of NaOH titrated with HCl 2N in the presence of acid/base indicator phenolphthalein. After reading, the same amount of NaOH was added and the containers were closed again. The difference between the amounts of acid needed to neutralize the sodium hydroxide in a control container and the treatments was equivalent to the amount of carbon dioxide produced by soil microorganisms. It was found that the residues influenced the microbial activity in different soil types, especially in the initial determinations, presenting themselves as good sources for mineralization and nutrient supply, the castor bean proportionating higher cumulative release of CO2 by microorganisms.

Lanthanum cobaltite black pigments with perovskite structure

In this work La1-xCaxCoO3 (x = 0-0.4) pigments were synthesized by the polymeric precursor method with heat treatments at 700, 800 and 900 C for 4 h. The powders were characterized by colorimetry, UV-vis spectroscopy and powder X-ray diffraction (XRD). The X-ray diffraction patterns showed the presence of a single phase perovskite, changing its structure from rhombohedral to cubic, when calcium was added to the lattice. All of the pigments had a black colour with a strong absorption over the whole of the visible spectrum as a consequence of the different oxidation states of cobalt and the high short-range disorder. The substitution of Ca2+ for La3+ did not influence the pigment colour but decreased its final cost. © 2013 Elsevier Ltd. All rights reserved.

O produto de moda para o portador de deficiência física: análise de desconforto

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência da estrutura de corantes azo na cinética de degradação por processo foto-Feton e ferro zero e na toxicidade

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação do efeito protetor do urucum e da bixina sobre a genotoxicidade induzida pelo antitumoral cisplatina em células da linhagem PC12

Pós-graduação em Alimentos e Nutrição - FCFAR

Exposição à concentração subletal de metilmercúrio: genotoxicidade e alterações na proliferação celular

O mercúrio é um metal que se destaca dos demais por se apresentar líquido em temperatura e pressão normais. Este xenobiótico se apresenta como a maior fonte de poluição em várias partes do mundo e tem como característica ser altamente tóxico ao Sistema Nervoso Central (SNC). O despejo é na forma líquida diretamente no solo e leito dos rios. Este metal pesado é complexado com vários elementos presentes no solo ou sedimentos sendo convertido à metilmercúrio (MeHg) pela microbiota aquática. O MeHg apresenta a capacidade de se acumular ao longo da cadeia trófica, um evento conhecido como biomagnificação, o qual afeta diretamente a vida humana. Nesse sentido, a Região Amazônica se destaca por possuir todos os componentes necessários para a manutenção do ciclo biogeoquímico do mercúrio, além de populações cronicamente expostas a este metal pesado, sendo este fato considerado um problema de saúde pública. Tem-se conhecimento que este xenobiótico após a exposição aguda a altas doses promove desordens relacionadas ao surgimento de processos degenerativos no SNC, entretanto, os efeitos a baixas concentrações ainda não são totalmente conhecidos. Nesse sentido, se destacam as células gliais que atuam como mediadores no processo de neurotoxicidade desse metal, principalmente em baixas concentrações. Apesar de este tipo celular exibir um importante papel no processo de intoxicação mercurial, a ação deste metal sobre as células glias é pouco conhecida, principalmente sobre o genoma e a proliferação celular. Desta forma, este trabalho se propõe a avaliar o efeito da exposição a este xenobiótico em baixa concentração sobre o material genético e a proliferação celular em células da linhagem glial C6. As avaliações bioquímica (atividade mitocondrial – medida pelo ensaio de MTT –) e morfofuncional (integridade da membrana – avaliada pelo ensaio com os corantes BE e AA –) confirmaram a ausência de morte celular após a exposição ao metal pesado na concentração de 3 μM por um intervalo de 24 horas. Mesmo sem promover processos de morte celular, o tratamento com esta concentração subletal de MeHg foi capaz de aumentar significativamente os níveis dos marcadores de genotoxicidade (fragmentação do DNA, formação de micronúcleos, pontes nucleoplásmica e brotos nucleares). Ao mesmo tempo, foi possível observar uma alteração no ciclo celular através do aumento do índice mitótico e uma mudança no perfil do ciclo celular com aumento da população celular nas fases S e G2/M, sugerindo um aprisionamento nessa etapa. Esta mudança no ciclo celular, provocada por 24h de exposição ao MeHg, foi seguida de uma redução no número de células viáveis e confluência celular 24h após a retirada do MeHg e substituição do meio de cultura, além do aumento no tempo de duplicação da cultura do mesmo. Este estudo demonstrou pela primeira vez que a exposição ao metilmercúrio em concentração baixa e subletal é capaz de promover eventos genotóxicos e distúrbios na proliferação celular em células de origem glial.

Avaliação de processos de degradação de corantes dispersos por técnicas eletroquímica e fotoeletroquímica usando eletrodos de Pt, filmes finos e nanotubos de 'TI'/'TIO IND. 2' e bicomponentes 'W'/'WO IND. 3'/'TIO IND. 2'

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Desenvolvimento de metodologia analítica ambientalmente mais amigável para a determinação de ureía em atrizes diversas

Pós-graduação em Química - IQ

Kinetic role of a histidine residue in the T1 copper site of the laccase from Rigidoporus lignosus

Laccases (benzendiol:oxygen oxidoreductases; EC 1.10.3.2) catalyze the oxidation of a broad range of substrates, such as polyphenols, dyes and pollutants, and thus these enzymes are widely applied in industrial, biotechnological and environmental fields. In order to improve their biotechnological applications, a deep knowledge of structural factors involved in controlling their activity, in various experimental conditions and on different substrates, is required. In the present study, a laccase from the mushroom Rigidoporus lignosus was kinetically characterized. In particular, the stability, the effects of pH, ionic strength and fluoride ion concentration on the kinetic parameters were investigated, using three di-hydroxy-benzene isomers (1,2-dihydroxy-benzene, 1,3-dihydroxy-benzene and 1,4-dihydroxy-benzene) as substrates. The catalytic constant values of the laccase showed a bell-shaped pH profile, with the same optimum pH and pK(a) values for all tested substrates. This behavior appears to be due to the presence of an ionizable residue in the enzyme active site. To identify this residue, the enzyme was derivatized with diethylpyrocarbonate to modify accessible histidine residues, which, according to structural data, are present in the active site of this enzyme. The kinetic behavior of the derivatized laccase was compared with that of the native enzyme and the derivatized residues were identified by mass spectrometry. Mass spectrometry and kinetic results suggest the main role of His-457 in the control of the catalytic activity of laccase from R. lignosus. (C) 2013 Elsevier B.V. All rights reserved.

Highly Ordered TiO2 Nanotubes for Electrochemical Sensing of Hair Dye Basic Brown 17

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Recent advances in nanoparticle carriers for coordination complexes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Produção de lacases pelo fungo filamentoso de origem marinha Peniophora sp. CBMAI 1063 em biorreator de bancada

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Fluorescence close to dielectric interfaces

The aim of the work was to study the correlation between the orientation and excited-state lifetimes of organic dyes close to dielectric interfaces. For this purpose, an experimental setup was designed and built, guiding the light through a prism in total internal reflection geometry. Fluorescence intensities and lifetimes for an ensemble of dye molecules were analyzed as a function of the excitation and detection polarizations. Working close to the total internal reflection angle, the differences between polarization combinations were enhanced. A classical electromagnetic model that assumes a chromophore as a couple of point-like electrical dipoles was developed. A numerical method to calculate the excitation and emission of dye molecules embedded in a multilayer system was implemented, by which full simulation of the time resolved fluorescence experiments was achieved. Free organic dyes and organic dyes covalently bound to polyelectrolyte chains were used. The polymer functionalization process avoided aggregation and provided control over the dyes position, within a few nanometers to the interface. Moreover, by varying the pH, the polymer chains could be deposited on different substrates with different conformations and the resulting fluorescence characteristics analyzed. Initially the fluorescence of organic dyes embedded in a polymer matrix was studied as a function of the distance between the fluorophores and the polymer-air interface. The non-radiative decay rate, vacuum decay rate and the relative angle between the excitation and emission dipoles of the chromophores could be determined. Different free organic dyes were deposited onto different dielectric spacers, as close as possible to the air-dielectric interface. Surprisingly, the fluorescence characteristics of dyes deposited onto polyelectrolyte layer were in good agreement with theoretical predictions of dyes in a polymer matrix, even when the layer was only 2 nm thick. When functionalized chains were deposited at low pH, on top of a polyelectrolyte spacer, the fluorescence had the characteristics of emitters embedded in a polymer matrix as well. Surface deposition at high pH showed an intermediate behaviour between emitters embedded in polymer and on top of the surface, in air. In general, for low pH values, the chains are deposited on a substrate in a train-like conformation. For high pH values, the chains are deposited in a loop-like conformation. As a consequence at low pH the functionalized polymer strongly interdigitates with the polyelectrolyte chains of the spacer, bringing most of the dyes inside the polymer. Thus, the fluorophores may experience the polymer as surrounding environment. On the other hand, for high pH values the dye-loaded chains adsorbed have a conformational arrangement of dense loops that extend away from the surface. Therefore many fluorophores experience the air as surrounding environment. Changing the spacer from polyelectrolyte to negatively charged silane produced contradictory results for lifetimes and intensities. The fluorescence intensities indicated the behaviour of emitters embedded in a polymer matrix, regardless of the pH value. On the other hand, for low pH values, the excited-state lifetimes showed that the emitters behaved as in air. For higher pH values, an intermediate behaviour between fluorophores located within and above of a dielectric film was observed. The poor agreement between theoretical and experimental data may be due to the simplified model utilized, by which the dipoles are assumed either in one side or in the other with respect to a geometrical air-dielectric interface. In the case when the dielectric film is constituted by the functionalized polymer chains themselves, reality is more complex and a different model may apply. Nevertheless, possible applications of the technique arise from a qualitative analysis.