Deposition and characterization of BiVO4 thin films and evaluation as photoanodes for methylene blue degradation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Structural Characterization of Nanocrystalline Sb-Doped SnO2 Xerogels by Multiedge X-ray Absorption Spectroscopy

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Synthesis, characterization and thermal studies on solid 3-methoxybenzoate of some bivalent transition metal ions

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

Surface characterization of Ti-7.5Mo alloy modified by biomimetic method

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

Effect of the microwave oven on structural, morphological and electrical properties of SrBi4Ti4O15 thin films grown on Pt/Ti/SiO2/Si substrates by a soft chemical method

Thin films of SrBi4Ti4O15 (SBTi), a prototype of the Bi-layered-ferroelectric oxide family, were obtained by a soft chemical method and crystallized in a domestic microwave oven. For comparison, films were also crystallized in a conventional method at 700 degrees C for 2 h. Structural and morphological characterization of the SBTi thin films were investigated by Xray diffraction (XRD) and atomic force microscopy (AFM), respectively. Using platinum coated silicon substrates, the ferroelectric properties of the films were determined. Remanent polarization P-r and a coercive field E-c values of 5.1 mu C/cm(2) and 135 kV/cm for the film thermally treated in the microwave oven and 5.4 mu C/cm(2) and 85 kv/cm for the film thermally treated in conventional furnace were found. The films thermally treated in the conventional furnace exhibited excellent fatigue-free characteristics up to 10(10) switching cycles indicating that SBTi thin films are a promising material for use in non-volatile memories. (C) 2007 Elsevier B.V. All rights reserved.

Encapsulation of titanium (IV) silsesquioxane into the NH4USY zeolite: Preparation, characterization and application

This work describes the encapsulation of titanium (IV) silsesquioxane into the supercavities of NH4USY ultra stabilized zeolite, after chemical treatment. The modified zeolite was characterized by Fourier transform infrared spectra, Nuclear magnetic resonance, scanning electronic microscopy, X-ray diffraction and thermogravity. This encapsulated titanium (IV) silsesquioxane can adsorb Azure A chloride after treatment with H3PO4, without modifier leaching problems. In an electrochemical study, the cyclic voltammograms of the graphite paste modified electrode, shows two redox couples with formal potential (E-0) -0. 1 V and 0.21 V to I and II redox couples respectively (v = 700 mV s(-1); Britton Robinson buffer (B-R) solution, pH 3) versus SCE ascribed to a monomer and dimmer of azure. This paper shows the use of ultra stabilized zeolite in the electrochemical field as host for molecules with nanometric dimensions. (c) 2006 Elsevier Ltd. All rights reserved.

Preparation, characterization and application of a nanostructured composite: Octakis(cyanopropyldimethylsiloxy)octasilsesquioxane

Octakis(cyanopropyldimethylsiloxy)octasilsesquioxane was prepared and characterized by C-13, Si-29 NMR (MAS), SEM, FF-IR, XRD and thermogravimetric techniques. The four groups alpha, beta, gamma, kappa (to the terminal silicon atom), associated with an acrylonitrile, were clearly seen in the C-13 NMR (alpha-CH2 at 17.9; P-CH2 at 31.3; gamma-CH, at 50.4; K-C N at 59.0 ppm). The Si-29 NMR spectrum of the final product, exhibits only Q type silicon signal, ascribed to Q(4) (-118.0 ppm). The presence of acrylonittile substituted for octameric cube confers a relative change phase and thermal stability to the material. With regard to the applications for this new material, it was intended, in this case, to react with Na-2[Fe(CN)(5)NH3] by chemical substitution. This composite was incorporated into a carbon paste electrode and the electrochemical studies were performed by cyclic voltammetry. The cyclic voltammogram of the modified graphite paste electrode, showed one redox couples with formal potential (E-1/2(ox)) = 0.24 V versus SCE. (c) 2006 Elsevier B.V. All rights reserved.

A novel nanostructured composite formed by interaction of copper octa(3-aminopropyl)octasilsesquioxane with azide ligands: Preparation, characterization and a voltammetric application

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

Retinal projections and neurochemical characterization of the pregeniculate nucleus of the common marmoset (Callithrix jacchus)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

No mutations found in exons of TP53, H-RAS and K-RAS genes in liver of male Wistar rats submitted to a medium-term chemical carcinogenesis assay

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

Immunocytochemical characterization of the pregeniculate nucleus and distribution of retinal and neuropeptide Y terminals in the suprachiasmatic nucleus of the Cebus monkey

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

Biological Performance of Chemical Hydroxyapatite Coating Associated With Implant Surface Modification by Laser Beam: Biomechanical Study in Rabbit Tibias

Purpose: Considering the potential of the association between laser ablation and smaller scale hydroxyapatite (HA) coatings to create a stable and bioactive surface on titanium dental implants, the aim of the present study was to determine, by the removal torque test, the effects of a surface treatment created by laser-ablation (Nd:YAG) and, later, thin deposition of HA particles by a chemical process, compared to implants with only laser-ablation and implants with machined surfaces.Materials and Methods: Forty-eight rabbits received I implant by tibia of the following surfaces: machined surface (MS), laser-modified surface (LMS), and biomimetic hydroxiapatite coated surface (HA). After 4, 8, and 12 weeks of healing, the removal torque was measured by a torque gauge. The surfaces studied were analyzed according to their topography, chemical composition, and roughness.Results: Average removal torque in each period was 23.28, 24.0, and 33.85 Ncm to MS, 33.0, 39.87, and 54.57 Ncm to LMS, and 55.42, 63.71 and 64.0 Ncm to HA. The difference was statistically significant (P < .05) between the LMS-MS and HA-MS surfaces in all periods of evaluation, and between LMS-HA to 4 and 8 weeks of healing. The surface characterization showed a deep, rough, and regular topography provided by the laser conditioning, that was followed by the HA coating.Conclusions: Based on these results, it was possible to conclude that the implants with laser surface modification associated with HA biomimetic coating can shorten the implant healing period by the increase of bone implant interaction during the first 2 months after implant placement. (C) 2009 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 67:1706-1715, 2009

Characterization of Five Different Implant Surfaces and Their Effect on Osseointegration: A Study in Dogs

Background: Chemical modification of implant surface is typically associated with surface topographic alterations that may affect early osseointegration. This study investigates the effects of controlled surface alterations in early osseointegration in an animal model.Methods: Five implant surfaces were evaluated: 1) alumina-blasting, 2) biologic blasting, 3) plasma, 4) microblasted resorbable blasting media (microblasted RBM), and 5) alumina-blasting/acid-etched (AB/AE). Surface topography was characterized by scanning electron microscopy and optical interferometry, and chemical assessment by x-ray photoelectron spectroscopy. The implants were placed in the radius of six dogs, remaining 2 and 4 weeks in vivo. After euthanization, specimens were torqued-to-interface failure and non-decalcified - processed for histomorphologic bone-implant contact, and bone area fraction-occupied evaluation. Statistical evaluation was performed by one-way analysis of variance (P < 0.05) and post hoc testing by the Tukey test.Results: The alumina-blasting surface presented the highest average surface roughness and mean root square of the surface values, the biologic blasting the lowest, and AB/AE an intermediate value. The remaining surfaces presented intermediate values between the biologic blasting and AB/AE. The x-ray photoelectron spectroscopy spectra revealed calcium and phosphorus for the biologic blasting and microblasted RBM surfaces, and the highest oxygen levels for the plasma, microblasted RBM, and AB/AE surfaces. Significantly higher torque was observed at 2 weeks for the microblasted RBM surface (P < 0.04), but no differences existed between surfaces at 4 weeks (P > 0.74). No significant differences in bone-implant contact and bone area fraction-occupied values were observed at 2 and 4 weeks.Conclusion: The five surfaces were osteoconductive and resulted in high degrees of osseointegration and biomechanical fixation. J Periodontol 2011;82:742-750.

Structural and functional characterization of BnSP-7, a Lys49 myotoxic phospholipase A(2) homologue from Bothrops neuwiedi pauloensis Venom

BnSP-7, a Lys49 myotoxic phospholipase A, homologue from Bothrops neuwiedi pauloensis venom, was structurally and functionally characterized. Several biological activities were assayed and compared with those of the chemically modified toxin involving specific amino acid residues, the cDNA produced from the total RNA by RT-PCR contained approximately 400 bp which codified its 121 amino acid residues with a calculated pi and molecular weight of 8.9 and 13,727, respectively. Its amino acid sequence showed strong similarities with several Lys49 phospholipase A, homologues from other Bothrops sp, venoms. By affinity chromatography and gel diffusion, it was demonstrated that heparin formed a complex with BnSP-7, held at least in part by electrostatic interactions. BnSP-7 displayed bactericidal activity and promoted the blockage of the neuromuscular contraction of the chick, biventer cervicis muscle. In addition to its in vivo myotoxic and edema-inducing activity, it disrupted artificial membranes, Both BnSP-7 and the crude venom released creatine kinase from the mouse gastrocnemius muscle and induced the development of a dose-dependent edema. His, Tyr, and Lys residues of the toxin were chemically modified by 4-bromophhenacyl bromide (BPB), 2-nitrobenzenesulfonyl fluoride (NBSF), and acetic anhydride (AA), respectively. Cleavage of its N-terminal octapeptide was achieved with cyanogen bromide (CNBr), the bactericidal action of BnSP-7 on Escherichia coli was almost completely abolished by acetylation or cleavage of the N-terminal octapeptide, the neuromuscular effect induced by BnSP-7 was completely inhibited by heparin, BPB, acetylation, and CNBr treatment. The creatine kinase releasing and edema-inducing effects were partially inhibited by heparin or modification by BPB and almost completely abolished by acetylation or cleavage of the N-terminal octapeptide, the rupture of liposomes by BnSP-7 and crude venom was dose and temperature dependent. Incubation of BnSP-7 with EDTA did not change this effect, suggesting a Ca2+-independent membrane lytic activity. BnSP-7 cross-reacted with antibodies raised against B. moojeni (MjTX-II), B. jararacussu (BthTX-I), and B. asper (Basp-II) myotoxins as well as against the C-terminal peptide (residues 115-129) from Basp-II. (C) 2000 Academic Press.

Geographic variations in the composition of myotoxins from Bothrops neuwiedi snake venoms: biochemical characterization and biological activity

(1) Venom pools from Bothrops neuwiedi (Bn) and from two subspecies, namely Bothrops neuwiedi pauloensis (Bnp) and Bothrops neuwiedi urutu (Bnu), collected in the States of São Paulo (SP) and Minas Gerais (MG), Brazil, were electrophoretically examined. Basic toxins with different isoelectric points were identified in the venom collected in São Paulo (BnSP). These toxins were absent in the corresponding pools from Minas Gerais (BnMG, BnpMG and BnuMG). (2) BnSP, but not BnMG, BnpMG or BnuMG, showed two myotoxins (pI congruent to 8.6 and 8.8, respectively) which were isolated by ion-exchange chromatography on CM-Sepharose. (3) From BnMG, three myotoxic isoforms (pI congruent to 8.2 and M-r = 13600) were isolated by chromatography on CM-Sepharose followed by reversed-phase high-performance liquid chromatography. (4) the chemical and biological characterization of these toxins showed a high similarity with the Lys-49 myotoxins from other bothropic venoms. (5) Doses up to 5 LD50 (i.p.) of p-bromophenacyl bromide alkylated BnSP-7 caused a total loss of lethality in 18-22-g mice, thus indicating that the LD50 was increased by greater than 5-fold. At this dose myotoxicity was also not detectable, but the edematogenic activity on the rat paw apparently did not change. (C) 1998 Elsevier B.V. All rights reserved.