Obtenção de materiais magnéticos para o estudo da propriedade magnetocalórica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Aderência aço-concreto: simulação numéricadosensaios de arranchamento pull-out e APULOT usando o programa ATENA

The bond between steel and concrete is essential for the existence of reinforced concrete structures, as both materials act together to absorb structural strain. The bond phenomenon is considered to be complex regarding many factors that affect it. Several types of bond tests have been proposed over years. One is the modified proposed of pull-out test, which was elaborated by Lorrain and Barbosa [1] called APULOT test (Appropriete pull-out-test). Based on experimental results obtained by Vale Silva[2] either by conventional pull-out tests, or by modified pull-out test, APULOT, seeks to know the numeric behavior of bond steel-concrete through a numerical simulation using a calculation code ATENA which is based on the Finite Element Method (FEM). The numerical simulation provided better evaluate the stress distribution and cracking that occurs during the test, thereby becoming a valuable tool to support the experimental project that aims to validation, validation partially or not recommend the modified bond test steel-concrete - APULOT test - as quality control test of structural concrete. The numerical results showed good representation compared to experimental results.

Diferentes técnicas de diagnóstico empregadas na estimativa de prevalência populacional de infecção por Cryptosporidium felis em gatos domiciliados no município de Araçatuba, São Paulo

Pós-graduação em Medicina Veterinária - FCAV

Preparação de soluções sólidas superficiais à base de alumina como catalisadores para síntese do biodiesel via rota etílica

Pós-graduação em Química - IBILCE

Síntese, caracterização estrutural, espectroscópica e análise do potencial fotocatalítico do aluminato de cobalto e potencial catalítico na preparação do biodiesel

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evaluación comparativa in vitro de la capacidad de sellado del sistema de conductos radiculares por diferentes técnicas

The aim of this study was to evaluate in vitro the sealing ability of the root canal using different techniques: cold lateral compaction, modified Hybrid Tagger, Thermafil and System B. Material and methods. Were used 116 human single-roots, included in resin blocks, sectioned longitudinally, attached to a device with screws and divided into four groups (n=29). After instrumentation using a bur, depression was made in each third of the root canal in each of the halves. Teeth were filled upon the different techniques. For evaluation of the quality, pictures were taken with a 1.5X magnification, photos and radiographs were utilized. After statistical analysis, were performed both macroscopic and radiographic evaluation, by Chi-square test (χ2). Results. The Thermafil technique showed better results in terms of sealing capacity, failures and homogeneity followed by modified Hybrid Tagger, the System B and cold lateral compaction. Conclusions. Thermafil was the technique that shown to be macroscopic, radiographic and homogeneously best over the other techniques evaluated in regard to the filling of the depressions made (AU)

Effect of hexadecyltrimethylammonium bromide-based microemulsions on the rate of decomposition of the beta-lactam antibiotic cephaclor

Microemulsions of hexadecyltrimethylammonium bromide (HTAB)/n-butanol/hexadecane/water catalyze the intramolecular degradation of cephaclor. The rate increase is a sensitive function of the microemulsion volume fraction and salt concentration. The effects of microemulsions, analyzed quantitatively using a pseudophase ion-exchange model, assumed that the extent of ion dissociation from the microemulsions varies with volume fraction. Comparison of micellar and microemulsion effects on the same reaction shows that microemulsions are less effective catalysts. Acceleration decreased significantly by increasing the relative proportion of n-butanol ratio in microemulsions and by addition of n-butanol in HTAB micelles. Comparison of the activation parameters of the reaction in aqueous solution, microemulsions, and micelles suggests that catalysis by both aggregates is driven mainly by entropic contributions.

Reparative phase events on periodontal disease progression: interpretation and considerations

Periodontal disease progress by destructive acute phases intercalated by reparative chronic phases. The aim of this study was to investigate the clinical and histological evidence of the periodontal disease reparative phase by analyzing bone wall conditions inside periodontal pockets and histologic images of periodontal pockets, identified in relevant publications. 81 patients with periodontitis, were randomly assigned into this study. Clinical and radiographic parameters were established to diagnose periodontal disease providing a sample of 133 diseased areas, which were treated by modified Widman flap. Documentation by digital photography were recorded in the surgery. Relevant publications showing histological images of periodontal pockets, were identified in Medline, PubMed and Google data base, were scanned and digitalized. All images obtained were evaluated and the presences of the reparative evidence in the zone around the underlying destroyed alveolar bone were critically analyzed. All periodontal bone defects, showed cortical bone reparations at different levels inside periodontal bone defects. All histologic images of periodontal pockets identified in relevant publications showed repaired gingival-attached connective tissue localized above underlying destroyed alveolar bone. All the evidences analyzed in this study suggested that periodontal disease is predominantly chronic, quiescent, showing reparative phases in different levels.

Dually fluorescent silica nanoparticles

The cationic dyes 9-aminoacridine (9AA) and safranine (Sf) were entrapped into silica spheres of about 0.2 mu m diameter prepared by modified Stober method. The fluorescent materials are investigated by steady-state and time-resolved emission, in addition of confocal fluorescence microscopy. Silica particles containing 9-aminoacridine (SP9AA) and safranine (SPSf or both dyes (SPSf9AA) are emissive particles. When both dyes are present in the same particle but loaded in sequential stages 9AA emission is quenched as a consequence of energy transfer from 9AA (donor) to Sf (acceptor). This result suggests that particle growing processes where the acceptor is incorporated first into the core do not prevent donor/acceptor pairs to be close due to an overlay of the concentration gradients of both dyes in a radial core-shell like distribution. (C) 2010 Elsevier B.V. All rights reserved.

Crystallization and preliminary X-ray diffraction of malate dehydrogenase from Plasmodium falciparum

The expression, purification, crystallization and preliminary X-ray diffraction characterization of malate dehydrogenase (MDH) from the malarial parasite Plasmodium falciparum (PfMDH) are reported. In order to gain a deeper understanding of the function and role of PfMDH, the protein was purified to homogeneity. The purified protein crystallized in space group P1, with unit-cell parameters a = 72, b = 157, c = 159 angstrom, a = 105, beta = 101, ? = 95 degrees. The resulting crystals diffracted to a maximal resolution of 2.24 angstrom and the structure has been solved by molecular replacement, with 16 monomers in the asymmetric unit. The 16 monomers are arranged into four independent tetramers, in agreement with previous reports demonstrating the tetrameric solution state of PfMDH. The X-ray structure of PfMDH is expected to clarify the differences in catalysis by PfMDH compared with other MDH family members and to provide a basis for the structure-based design of specific PfMDH inhibitors as well as general MDH inhibitors.

Cough and dyspnea during bronchoconstriction: comparison of different stimuli

Abstract Background Bronchial challenge tests are used to evaluate bronchial responsiveness in diagnosis and follow-up of asthmatic patients. Challenge induced cough has increasingly been recognized as a valuable diagnostic tool. Various stimuli and protocols have been employed. The aim of this study was to compare cough and dyspnea intensity induced by different stimuli. Methods Twenty asthmatic patients underwent challenge tests with methacholine, bradykinin and exercise. Cough was counted during challenge tests. Dyspnea was assessed by modified Borg scale and visual analogue scale. Statistical comparisons were performed by linear mixed-effects model. Results For cough evaluation, bradykinin was the most potent trigger (p < 0.01). In terms of dyspnea measured by Borg scale, there were no differences among stimuli (p > 0.05). By visual analogue scale, bradykinin induced more dyspnea than other stimuli (p ≤ 0.04). Conclusion Bradykinin seems to be the most suitable stimulus for bronchial challenge tests intended for measuring cough in association with bronchoconstriction.

Paralelización del código de desenredo y suavizado de mallas de tetraedros "S.U.S Code"

Máster Universitario en Sistemas Inteligentes y Aplicaciones Numéricas en Ingeniería (SIANI)

Studio della subunità epsilon della DNA polimerasi III di Escherichia coli: stabilità e interazione con la subunità polimerasica

Faithful replication of DNA from one generation to the next is crucial for long-term species survival. Genomic integrity in prokaryotes, archaea and eukaryotes is dependent on efficient and accurate catalysis by multiple DNA polymerases. Escherichia coli possesses five known DNA polymerases (Pol). DNA polymerase III holoenzyme is the major replicative polymerase of the Escherichia coli chromosome (Kornberg, 1982). This enzyme contains two Pol III cores that are held together by a t dimer (Studwell-Vaughan and O’Donnell, 1991). The core is composed of three different proteins named α-, ε- and θ-subunit. The α-subunit, encoded by dnaE, contains the catalytic site for DNA polymerisation (Maki and Kornberg, 1985), the ε-subunit, encoded by dnaQ, contains the 3′→5′ proofreading exonuclease (Scheuermann, et al., 1983) and the θ-subunit, encoded by hole, that has no catalytic activity (Studwell-Vaughan, and O'Donnell, 1983). The three-subunit α–ε–θ DNA pol III complex is the minimal active polymerase form purified from the DNA pol III holoenzyme complex; these three polypeptides are tightly associated in the core (McHenry and Crow, 1979) Despite a wealth of data concerning the properties of DNA polymerase III in vitro, little information is available on the assembly in vivo of this complex enzyme. In this study it is shown that the C-terminal region of the proofreading subunit is labile and that the ClpP protease and the molecular chaperones GroL and DnaK control the overall concentration in vivo of ε. Two α-helices (comprising the residues E311-M335 and G339-D353, respectively) of the N-terminal region of the polymerase subunit were shown to be essential for the binding to ε. These informations could be utilized to produce a conditional mutator strain in which proofreading activity would be titrated by a a variant that can only bind e and that is polymerase-deficient. In this way the replication of DNA made by DNA Pol-III holoenzyme would accordingly become error-prone.

Cluster-derived Gold/Iron catalysts for environmental applications

During the last years we assisted to an exponential growth of scientific discoveries for catalysis by gold and many applications have been found for Au-based catalysts. In the literature there are several studies concerning the use of gold-based catalysts for environmental applications and good results are reported for the catalytic combustion of different volatile organic compounds (VOCs). Recently it has also been established that gold-based catalysts are potentially capable of being effectively employed in fuel cells in order to remove CO traces by preferential CO oxidation in H2-rich streams. Bi-metallic catalysts have attracted increasing attention because of their markedly different properties from either of the costituent metals, and above all their enhanced catalytic activity, selectivity and stability. In the literature there are several studies demostrating the beneficial effect due to the addition of an iron component to gold supported catalysts in terms of enhanced activity, selectivity, resistence to deactivation and prolonged lifetime of the catalyst. In this work we tried to develop a methodology for the preparation of iron stabilized gold nanoparticles with controlled size and composition, particularly in terms of obtaining an intimate contact between different phases, since it is well known that the catalytic behaviour of multi-component supported catalysts is strongly influenced by the size of the metal particles and by their reciprocal interaction. Ligand stabilized metal clusters, with nanometric dimensions, are possible precursors for the preparation of catalytically active nanoparticles with controlled dimensions and compositions. Among these, metal carbonyl clusters are quite attractive, since they can be prepared with several different sizes and compositions and, moreover, they are decomposed under very mild conditions. A novel preparation method was developed during this thesis for the preparation of iron and gold/iron supported catalysts using bi-metallic carbonyl clusters as precursors of highly dispersed nanoparticles over TiO2 and CeO2, which are widely considered two of the most suitable supports for gold nanoparticles. Au/FeOx catalysts were prepared by employing the bi-metallic carbonyl cluster salts [NEt4]4[Au4Fe4(CO)16] (Fe/Au=1) and [NEt4][AuFe4(CO)16] (Fe/Au=4), and for comparison FeOx samples were prepared by employing the homometallic [NEt4][HFe3(CO)11] cluster. These clusters were prepared by Prof. Longoni research group (Department of Physical and Inorganic Chemistry- University of Bologna). Particular attention was dedicated to the optimization of a suitable thermal treatment in order to achieve, apart from a good Au and Fe metal dispersion, also the formation of appropriate species with good catalytic properties. A deep IR study was carried out in order to understand the physical interaction between clusters and different supports and detect the occurrence of chemical reactions between them at any stage of the preparation. The characterization by BET, XRD, TEM, H2-TPR, ICP-AES and XPS was performed in order to investigate the catalysts properties, whit particular attention to the interaction between Au and Fe and its influence on the catalytic activity. This novel preparation method resulted in small gold metallic nanoparticles surrounded by highly dispersed iron oxide species, essentially in an amorphous phase, on both TiO2 and CeO2. The results presented in this thesis confirmed that FeOx species can stabilize small Au particles, since keeping costant the gold content but introducing a higher iron amount a higher metal dispersion was achieved. Partial encapsulation of gold atoms by iron species was observed since the Au/Fe surface ratio was found much lower than bulk ratio and a strong interaction between gold and oxide species, both of iron oxide and supports, was achieved. The prepared catalysts were tested in the total oxidation of VOCs, using toluene and methanol as probe molecules for aromatics and alchols, respectively, and in the PROX reaction. Different performances were observed on titania and ceria catalysts, on both toluene and methanol combustion. Toluene combustion on titania catalyst was found to be enhanced increasing iron loading while a moderate effect on FeOx-Ti activity was achieved by Au addition. In this case toluene combustion was improved due to a higher oxygen mobility depending on enhanced oxygen activation by FeOx and Au/FeOx dispersed on titania. On the contrary ceria activity was strongly decreased in the presence of FeOx, while the introduction of gold was found to moderate the detrimental effect of iron species. In fact, excellent ceria performances are due to its ability to adsorb toluene and O2. Since toluene activation is the determining factor for its oxidation, the partial coverage of ceria sites, responsible of toluene adsorption, by FeOx species finely dispersed on the surface resulted in worse efficiency in toluene combustion. Better results were obtained for both ceria and titania catalysts on methanol total oxidation. In this case, the performances achieved on differently supported catalysts indicate that the oxygen mobility is the determining factor in this reaction. The introduction of gold on both TiO2 and CeO2 catalysts, lead to a higher oxygen mobility due to the weakening of both Fe-O and Ce-O bonds and consequently to enhanced methanol combustion. The catalytic activity was found to strongly depend on oxygen mobility and followed the same trend observed for catalysts reducibility. Regarding CO PROX reaction, it was observed that Au/FeOx titania catalysts are less active than ceria ones, due to the lower reducibility of titania compared to ceria. In fact the availability of lattice oxygen involved in PROX reaction is much higher in the latter catalysts. However, the CO PROX performances observed for ceria catalysts are not really high compared to data reported in literature, probably due to the very low Au/Fe surface ratio achieved with this preparation method. CO preferential oxidation was found to strongly depend on Au particle size but also on surface oxygen reducibility, depending on the different oxide species which can be formed using different thermal treatment conditions or varying the iron loading over the support.

Cardiac c-kit+AT2+ cell population is increased in response to ischemic injury and supports cardiomyocyte performance

The expression pattern of angiotensin AT2 receptors with predominance during fetal life and upregulation under pathological conditions during tissue injury/repair process suggests that AT2 receptors may exert an important action in injury/repair adaptive mechanisms. Less is known about AT2 receptors in acute ischemia-induced cardiac injury. We aimed here to elucidate the role of AT2 receptors after acute myocardial infarction. Double immunofluorescence staining showed that cardiac AT2 receptors were mainly detected in clusters of small c-kit+ cells accumulating in peri-infarct zone and c-kit+AT2+ cells increased in response to acute cardiac injury. Further, we isolated cardiac c-kit+AT2+ cell population by modified magnetic activated cell sorting and fluorescence activated cell sorting. These cardiac c-kit+AT2+ cells, represented approximately 0.19% of total cardiac cells in infarcted heart, were characterized by upregulated transcription factors implicated in cardiogenic differentiation (Gata-4, Notch-2, Nkx-2.5) and genes required for self-renewal (Tbx-3, c-Myc, Akt). When adult cardiomyocytes and cardiac c-kit+AT2+ cells isolated from infarcted rat hearts were cocultured, AT2 receptor stimulation in vitro inhibited apoptosis of these cocultured cardiomyocytes. Moreover, in vivo AT2 receptor stimulation led to an increased c-kit+AT2+ cell population in the infarcted myocardium and reduced apoptosis of cardiomyocytes in rats with acute myocardial infarction. These data suggest that cardiac c-kit+AT2+ cell population exists and increases after acute ischemic injury. AT2 receptor activation supports performance of cardiomyocytes, thus contributing to cardioprotection via cardiac c-kit+AT2+ cell population.