X-ray absorption spectroscopy study on La0.6Sr0.4CoO3 and La0.6Sr0.4Co1¡yFeyO3 nanotubes and nanorods for IT-SOFC cathodes.

In the last years, extensive research has been devoted to develop novel materials and structures with high electrochemical performance for intermediate-temperatures solid-oxide fuel cells (IT-SOFCs) electrodes. In recent works, we have investigated the structural and electrochemical properties of La0:6Sr0:4CoO3 (LSCO) and La0:6Sr0:4Co1¡yFeyO3 (LSCFO) nanostructured cathodes, finding that they exhibit excellent electrocatalytic properties for the oxygen reduction reaction [1,2]. These materials were prepared by a pore-wetting technique using polycarbonate porous membranes as templates. Two average pore sizes were used: 200 nm and 800 nm. Our scanning electronic microscopy (SEM) study showed that the lower pore size yielded nanorods, while nanotubes were obtained with the bigger pore size. All the samples were calcined at 1000oC in order to produce materials with the desired perovskite-type crystal structure. In this work, we analyze the oxidation states of Co and Fe and the local atomic order of LSCO and LSCFO nanotubes and nanowires for various compositions. For this pur- pose we performed XANES and EXAFS studies on both Co and Fe K edges. These measurements were carried out at the D08B-XAFS2 beamline of the Brazilian Synchrotron Light Laboratory (LNLS). XANES spectroscopy showed that Co and Fe only change slightly their oxidation state upon Fe addition. Surprisingly, XANES results indicated that the content of oxygen vacancies is low, even though it is well-known that these materials are mixed ionic-electronic conductors. EXAFS results were consistent with those expected according to the rhombohedral crystal structure determined in previous X-ray powder dffraction investigations. [1] M.G. Bellino et al, J. Am. Chem. Soc. 129 (2007) 3066 [2] J.G. Sacanell et al., J. Power Sources 195 (2010) 1786

In-situ XANES experiments on Ni K-edge in mesoporous ZrO2-CeO2:Ni.

Ordered mesoporous ZrO2-CeO2 mixed oxides are potential candidates for catalytic applications. These systems, used as anodes in solid oxide fuel cells (SOFC), may lead to better performance of SOFCs, due to an enhancement on surface area, aiming to achieve a lower working temperature. The aim of this studies is to evaluate the reduction capacity of Ni2+ to Ni in ZrO2-x(mol)%CeO2 (x=50 and 90) samples impregnated with 60(wt.)%NiO. The synthesis was made with Zr and Ce chloride precursors, HCl aqueous solution, Pluronic P123, NH4OH to adjust the pH (3-4) and a teflon autoclave to perform a hydrothermal treatment (80oC/48h). The samples were dried and calcined, until 540oC in N2 and 4 hours in air. The NiO impregnation was made with an ethanol dispersion of Ni(NO3)£6H2O. The powder was calcinated in air until 350oC for 2 hours. Temperature-resolved XANES data at the Ni K-edge were collected at the DXAS beam line of the LNLS in transmission mode, using a Si(111) monochromator and a CCD detector. Sample preparation consisted of mixing »6mg of the powder samples with boron nitride and pressing into pellets. The data were acquired during an experiment of temperature programmed reduction (TPR) under a 5% H2/He until 600oC and mixtures of 20%CH4:5%O2/He, at temperatures from 400 to 600oC. All the reactions were monitored with a mass spectrometer. The data was analyzed with a linear combination fit of 2 standards for each valence number using Athena software. The Ni K-edge experiments demonstrated that for both contents of CeO2, NiO embedded in the porous zirconia-ceria matrix reduces at lower temperatures than pure NiO, revealing that the ZrO2-CeO2 support improves the reduction of impregnated NiO. Ni was oxidized to NiO after all reactions with methane and oxygen. Hydrogenated carbonaceous species were detected, but under reducing conditions, the hydrocarbon compounds are removed. The reaction of total oxidation of methane CH4:O2 (1:2 ratio) was observed at lower temperatures (around 400oC) for both samples.

Structural and textural studies of NiO impregnation in mesoporous ZrO2-CeO2 for catalysis applications.

The synthesis of zirconia-based ordered mesoporous structures for catalytic applications is a research area under development. These systems are also potential candidates as anodes in intermediate temperature solid oxide fuel cells (it-SOFC) due to an enhancement on their surface area [1-4]. The structural features of mesoporous zirconia-ceria materials in combination with oxygen storage/release capacity (OSC) are crucial for various catalytic reactions. The direct use of hydrocarbons as fuel for the SOFC (instead of pure H2), without the necessity of reforming and purification reactors can improve global efficiency of these systems [4]. The X-ray diffraction data showed that ZrO2-x%CeO2 samples with x>50 are formed by a larger fraction of the cubic phase (spatial group Fm3m), while for x<50 the major crystalline structure is the tetragonal phase (spatial group P42/nmc). The crystallite size of the cubic phase increases with increase in ceria content. The tetragonal crystallite size decreases when ceria content increases. After impregnation, the Rietveld analysis showed a NiO content around 60wt.% for all samples. The lattice parameters for the ZrO2 tetragonal phase are lower for higher ZrO2 contents, while for all samples the cubic NiO and CeO2 parameters do not present changes. The calculated densities are higher for higher ceria content, as expected. The crystallite size of NiO are similar (~20nm) for all samples and 55nm for the NiO standard. Nitrogen adsorption experiments revealed a broader particle size distribution for higher CeO2 content. The superficial area values were around 35m2/g for all samples, the average pore diameter and pore volumes were higher when increasing ceria content. After NiO impregnation the particle size distribution was the same for all samples, with two pore sizes, the first around 3nm and a broader peak around 10nm. The superficial area increased to approximately 45m2/g for all samples, and the pore volume was also higher after impregnation and increased when ceria content increased. These results point up that the impregnation of NiO improves the textural characteristics of the pristine material. The complementary TEM/EDS images present a homogeneous coating of NiO particles over the ZrO2-x%CeO2 support, showing that these samples are excellent for catalysis applications. [1] D. Y. Zhao, J. Feng, Q. Huo, N. Melosh, G. H. Fredrickson, B. F. Chmelka, G. D. Stucky, Science 279, 548-552 (1998). [2] C. Yu, Y. Yu, D. Zhao, Chem. Comm. 575-576 (2000). [3] A. Trovarelli, M. Boaro, E. Rocchini, C. de Leitenburg, G. Dolcetti, J. Alloys Compd. 323-324 (2001) 584-591. [4] S. Larrondo, M. A. Vidal, B. Irigoyen, A. F. Craievich, D. G. Lamas, I. O. Fábregas, et al. Catal. Today 107–108 (2005) 53-59.

Diagnosis of rabies and eastern and western equine viral encephalitides in equids by multiplex Hemi-Nested RT-PCR technique

Financial support: CNPq and Pasteur Institute of São Paulo

Reactive sputter magnetron reactor for preparation of thin films and simultaneous in-situ structural study by X-ray diffraction.

Reactive Sputter Magnetron (RSM) is a widely used technique to thin films growing of compounds both, in research laboratories and in industrial processes. The nature of the deposited compound will depend then on the nature of the magnetron target and the nature of the ions generated in the plasma. One important aspect of the problem is the knowledge of the evolution of the film during the process of growing itself. In this work, we present the design, construction of a chamber to be installed in the Huber goniometer in the XRD2 line of LNLS in Campinas, which allows in situ growing kinetic studies of thin films.

20S Proteasome: Structural study using SAXS.

The process of intracellular proteolysis (protein degradation) is a regulatory mechanism of cellular homeostasis with the same level of importance as gene expression.The proteasome is a proteolytic complex responsible for protein degradation and consists of a catalytic core unit called the 20S(20SPT) where the hydrolysis occurs, engaged in one or both ends by regulatory units, called 19S, responsible for the recognition of poly-ubiquitylated proteins, unfolding and translocation of them to the 20S catalytic chamber. However, the catalytic unit (20SPT) can also degrade not marked proteins with poly-ubiquitin tail, as in the case of oxidized proteins. Oxidized proteins have a tendency to form aggregates (a phenomenon that underlies human neurodegenerative diseases), and therefore they must be effectively removed from the living cell. Interestingly, the cells have approximately 1/3 of proteasome without regulatory units, i.e. only the 20S catalytic unit.

The study the properties structurals and elastics of phases lamellar of lipid.

Lamellar systems composed of lipid bilayers have been widely used as model system for investigating properties of biological membranes, interactions between membranes and with biomolecules. The composition of the membrane determines its three dimensional shape and its properties such as rigidity and compressibility which play an important role on membrane fusion, protein adhesion, interactions between proteins, etc. We present a systematic study of a lamellar system composed of lecithin and a commercial co-surfactant (Simusol), which is a mixture of ethoxylated fatty acids. Using X ray scattering and a new procedure to fit X-ray experimental data, we determine relevant parameters characterizing the lamellar structure, varying membrane composition from 100% of lecithin to 100% of Simulsol. We present experimental data illustrating the swelling behavior for the membrane of different compositions and the respective behavior of the Caillé parameter. From and GISAXS experiments on oriented films under controlled humidity we investigate the compressibility of the lamellar phase and the effect of incorporating co-surfactant. Combining the Caillé parameter and compressibility studies we determine the bending rigidity of membranes. The results obtained with this experimental approach and new procedure to fit X-ray experimental allows us to identify structural changes in the bilayer depending both on hydration and co-surfactant content, with implications on elastic properties of membranes.

Size-dependent phase transitions in nanostructured zirconia-scandia solid solutions.

Size effects on phase stability and phase transitions in technologically relevant materials have received growing attention. Several works reported that metastable phases can be retained at room temperature in nanomaterials, these phases generally corresponding to the high-temperature polymorph of the same material in bulk state. Additionally, size-dependent shifts in solubility limits and/or in the transition temperatures for on heating or on cooling cycles have been observed. ZrO2-Sc2O3 (zirconia-scandia) solid solutions are known to exhibit very high oxygen ion conductivity provided their structure is composed of cubic and/or pseudocubic tetragonal phases. Unfortunately, for solid zirconia-scandia polycrystalline samples with typical micrometrical average crystal sizes, the high-conductivity cubic phase is only stable above 600°C. Depending on composition, three low-conductivity rhombo-hedral phases (β, γ and δ) are stable below 600°C down to room temperature, within the compositional range of interest for SOFCs. In previous investigations, we showed that the rhombohedral phases can be avoided in nanopowders with average crystallite size lower than 35 nm.

The alpha-cluster model applied to 74Ge.

There are few studies using cluster models in the nuclei around the intermediate and heavy mass regions. The alpha-cluster model is based on the interaction between an alpha particle and a nucleus chosen as a core. This model can be applied to nuclear system where alpha-cluster stability is expected and the application in light and intermediate mass nuclei was able to give consistent descriptions of experimental data.

As redes sociotécnicas da comunidade gamer : Habilidades cognitivas, capitalismo cognitivo e pirataria no orkut

In the perspective of the so called 'cognitive capitalism', this paper intends to analyze the sharing and customization strategies developed in Brazilian online game communities. Under Bruno Latour's Actor-Network Theory (ANT), this work describes these socio-technical networks electing the human and non human relevant actants for their role on what could also be depicted as an distributed cognitive process (HUTCHINS, 2000). This alternative way of participative consumption deals with the social and creative production of tutorials; in-game and out-game editing and all sorts of gathering, organization and distribution of virtual data. The communities studied are related to the game Pro Evolution Soccer (PES) in their multiple platforms

As redes sociotécnicas da comunidade gamer : Habilidades cognitivas, capitalismo cognitivo e pirataria no orkut

In the perspective of the so called 'cognitive capitalism', this paper intends to analyze the sharing and customization strategies developed in Brazilian online game communities. Under Bruno Latour's Actor-Network Theory (ANT), this work describes these socio-technical networks electing the human and non human relevant actants for their role on what could also be depicted as an distributed cognitive process (HUTCHINS, 2000). This alternative way of participative consumption deals with the social and creative production of tutorials; in-game and out-game editing and all sorts of gathering, organization and distribution of virtual data. The communities studied are related to the game Pro Evolution Soccer (PES) in their multiple platforms

As redes sociotécnicas da comunidade gamer : Habilidades cognitivas, capitalismo cognitivo e pirataria no orkut

In the perspective of the so called 'cognitive capitalism', this paper intends to analyze the sharing and customization strategies developed in Brazilian online game communities. Under Bruno Latour's Actor-Network Theory (ANT), this work describes these socio-technical networks electing the human and non human relevant actants for their role on what could also be depicted as an distributed cognitive process (HUTCHINS, 2000). This alternative way of participative consumption deals with the social and creative production of tutorials; in-game and out-game editing and all sorts of gathering, organization and distribution of virtual data. The communities studied are related to the game Pro Evolution Soccer (PES) in their multiple platforms

RELIGIÃO, CORPO E EMOÇÃO: EDUCAÇÃO DOS SENTIDOS E HABITUS DE CLASSE NA IGREJA COMUNIDADE DA GRAÇA NO ABC PAULISTA

O objeto de estudo desta pesquisa é a Comunidade da Graça, presente há dez anos em São Bernardo do Campo, região do ABC paulista. Analisa-se o lugar da emoção religiosa e sua relação com a educação dos sentidos nesta confraria protestante pentecostal formada majoritariamente por pessoas de classe média, como propiciadora da assimilação de um habitus e de um forte auto-controle individual evidenciando a eficácia do adestramento corporal pela via da religião. Imersa em uma realidade social de muitas mudanças que provocam reconfigurações das religiões, no tipo específico de pentecostalismo estudado nota-se que, na gestão dos bens simbólicos, o ingrediente emocional é o principal acessório a fim de responder às demandas coletivas e individuais deste público religioso. Se há alguns anos a centralidade cúltica do protestantismo pentecostal estava no ouvir a prédica e reviver a experiência do pentecostes cristão, hoje em dia o foco neste é a emoção que deve perpassar todo o culto. O mesmo ocorre nos dois espaços catequéticos privilegiados desta igreja, a saber, a reunião no templo chamada de Conhecendo as Escrituras e os encontros de grupos nos lares. Esta mudança se evidencia, também, nos corpos dos fiéis, pois estes se constróem e modelam-se à realidade social vigente e expressam as experiências vivenciadas neste contexto. A partir da observação dos cultos e reuniões catequéticas desta igreja, analisa-se neste trabalho o modo como a emoção religiosa é construída, difundida e reproduzida, levando-se em consideração as condições sociais e econômicas específicas do grupo religioso em questão.(AU)

RELIGIÃO, CORPO E EMOÇÃO: EDUCAÇÃO DOS SENTIDOS E HABITUS DE CLASSE NA IGREJA COMUNIDADE DA GRAÇA NO ABC PAULISTA

O objeto de estudo desta pesquisa é a Comunidade da Graça, presente há dez anos em São Bernardo do Campo, região do ABC paulista. Analisa-se o lugar da emoção religiosa e sua relação com a educação dos sentidos nesta confraria protestante pentecostal formada majoritariamente por pessoas de classe média, como propiciadora da assimilação de um habitus e de um forte auto-controle individual evidenciando a eficácia do adestramento corporal pela via da religião. Imersa em uma realidade social de muitas mudanças que provocam reconfigurações das religiões, no tipo específico de pentecostalismo estudado nota-se que, na gestão dos bens simbólicos, o ingrediente emocional é o principal acessório a fim de responder às demandas coletivas e individuais deste público religioso. Se há alguns anos a centralidade cúltica do protestantismo pentecostal estava no ouvir a prédica e reviver a experiência do pentecostes cristão, hoje em dia o foco neste é a emoção que deve perpassar todo o culto. O mesmo ocorre nos dois espaços catequéticos privilegiados desta igreja, a saber, a reunião no templo chamada de Conhecendo as Escrituras e os encontros de grupos nos lares. Esta mudança se evidencia, também, nos corpos dos fiéis, pois estes se constróem e modelam-se à realidade social vigente e expressam as experiências vivenciadas neste contexto. A partir da observação dos cultos e reuniões catequéticas desta igreja, analisa-se neste trabalho o modo como a emoção religiosa é construída, difundida e reproduzida, levando-se em consideração as condições sociais e econômicas específicas do grupo religioso em questão.(AU)

Código Penitenciário tipo para a América Latina

Discorre sobre a reunião realizada em Costa Rica, de 18 a 23 de março de 1974, onde se discutiram os seguintes temas: os problemas penitenciários da América Latina (suas principais características: 1) regime prisional anterior as penas privativas da liberdade; 2) execução das penas privativas da liberdade). Formação do pessoal penitenciário. cooperação regional e codigo penitenciário tipo para a América Latina (bases para a sua elaboração)