Structural, microstructural, and transport properties of highly oriented LaNiO3 thin films deposited on SrTiO3(100) single crystal

Electrical conductive textured LaNiO3/SrTiO3 (100) thin films were successfully produced by the polymeric precursor method. A comparison between features of these films of LaNiO3 (LNO) when heat treated in a conventional furnace (CF) and in a domestic microwave (MW) oven is presented. The x-ray diffraction data indicated good crystallinity and a structural orientation along the (h00) direction for both films. The surface images obtained by atomic force microscopy revealed similar roughness values, whereas films LNO-MW present slightly smaller average grain size (similar to 80 nm) than those observed for LNO-CF (60-150 nm). These grain size values were in good agreement with those evaluated from the x-ray data. The transport properties have been studied by temperature dependence of the electrical resistivity rho(T) which revealed for both films a metallic behavior in the entire temperature range studied. The behavior of rho(T) was investigated, allowing to a discussion of the transport mechanisms in these films. (C) 2007 American Institute of Physics.

Very large dielectric constant of highly oriented Pb1-xBaxTiO3 thin films prepared by chemical deposition

Highly (100) oriented Pb0.8Ba0.2TiO3/LaNiO3 structures were grown on LaAlO3(100) substrates by using a wet, soft chemical method and crystallized by the microwave oven technique. The Au/PBT/LaNiO3/LaAlO3 capacitor shows a hysteresis loop with remnant polarization, P-r, of 15 muC/cm(2), and coercive field, E-c, of 47 kV/cm at an applied voltage of 3 V, along with a dielectric constant over 1800. Atomic force microscopy showed that Pb0.8Ba0.2TiO3 is composed of large grains about 300 nm. The experimental results demonstrated that the microwave preparation is rapid, clean, and energy efficient. Therefore, we demonstrated that the combination of the soft chemical method with the microwave process is a promising technique to grow highly oriented thin films with excellent dielectric and ferroelectric properties, which can be used in various integrated device applications. (C) 2004 American Institute of Physics.

Highly selective nickel ethylene oligomerization catalysts based on sterically hindered tris(pyrazolyl)borate ligands

The reaction of TlTp' (Tp' = HB(3-mesitylpyrazolyl)(3)(-) (Tp(Ms)), HB(3-mesitylpyrazolyl)(2)(5-mesitylpyrazolyl)(-) (Tp(Ms)*)) with NiCl(2).6H(2)O affords Tp(Ms)NiCl (1) and Tp(Ms)*NiCl (2) in good yield. The compound 2 undergoes an isomerization process to form [{Tp(Ms)**}NiCl](2) (3) (Tp(Ms)** = HB(5-mesitylpyrazolyl)(2)(3-mesitylpyrazolyl)(-)) in 68% yield. Treatment of the tris(pyrazolyl)-borate nickel compounds 1 and 2 with alkylaluminum cocatalysts such as methylalumoxane (MAO) and trimethylaluminum (TMA) in toluene generates active catalysts for ethylene oligomerization. The compound 1 shows turnover frequencies in the range of (2.2-43.1) x 10(3) h(-1). Oligomerization reaction conditions can be adjusted that lead to selectivities as high as 81% for butene-1.

Highly swollen liquid crystals as new reactors for the synthesis of nanomaterials

Synthesis and self-assembly of nanomaterials can be controlled by the properties of soft matter. on one hand, dedicated nanoreactors such as reverse microemulsions or miniemulsions can be designed. on the other hand, direct shape control can be provided by the topology of liquid crystals that confine the reacting medium within a specific geometry. In the first case, the preparation of micro- or miniemulsions generally requires energetic mechanical stirring. The second approach uses thermodynamically stable systems, but it remains usually limited to binary (water + surfactant) systems. We report the preparation of different families of materials in highly ordered quaternary mediums that exhibit a liquid crystal structure with a high cell parameter. They were prepared with the proper ratios of salted water, nonpolar solvent, surfactant. and cosurfactants that form spontaneously swollen hexagonal phases. These swollen liquid crystals can be prepared from all classes of surfactants (cationic, anionic, and nonionic). They contain a regular network of parallel cylinders, whose diameters can be swollen with a nonpolar solvent, that are regularly spaced in a continuous aqueous salt solution. We demonstrate in the present report that both aqueous and organic phases can be used as nanoreactors for the preparation of materials. This property is illustrated by various examples such as the synthesis of platinum nanorods prepared in the aqueous phase or zirconia needles or the photo- or gamma-ray-induced polymerization of polydiacetylene in the organic phase. In all cases, materials can be easily extracted and their final shapes are directed by the structure-directing effect imposed by the liquid crystal.

From tin oxalate to (Fe, Co, Nb)-doped SnO(2): Sintering behavior, microstructural and electrical features

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

Non-leachable highly luminescent ordered mesoporous SiO2 spherical particles

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Magnesium-enriched hydroxyapatite at immediate implants: a histomorphometric study in dogs

AimTo evaluate the influence of magnesium-enriched hydroxyapatite (MHA) (SintLife (R)) on bone contour preservation and osseointegration at implants placed immediately into extraction sockets.Material and methodsIn the mandibular pre-molar region, implants were installed immediately into extraction sockets of six Labrador dogs. MHA was placed at test sites, while the control sites did not receive augmentation materials. Implants were intended to heal in a submerged mode. After 4 months of healing, the animals were sacrificed, and ground sections were obtained for histomorphometric evaluation.ResultsAfter 4 months of healing, one control implant was not integrated leaving n=5 test and control implants for evaluation. Both at the test and the control sites, bone resorption occurred. While the most coronal bone-to-implant contact was similar between test and control sites, the alveolar bony crest outline was maintained to a higher degree at the buccal aspect of the test sites (loss: 0.7 mm) compared with the control sites (loss: 1.2 mm), even though this difference did not reach statistical significance.ConclusionsThe use of MHA to fill the defect around implants placed into the alveolus immediately after tooth extraction did not contribute significantly to the maintenance of the contours of the buccal alveolar bone crest.To cite this article:Caneva M, Botticelli D, Stellini E, Souza SLS, Salata LA, Lang NP. Magnesium-enriched hydroxyapatite at immediate implants: a histomorphometric study in dogs.Clin. Oral Impl. Res. 22, 2011; 512-517doi: 10.1111/j.1600-0501.2010.02040.x.

Electrochemical sensor highly selective for estradiol valerate determination based on a modified carbon paste with iron tetrapyridinoporphyrazine

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Preparation, characterization and electrochemical studies of dinuclear copper(II) complexes with pseudohalides and bidentate amines on platinum electrode in acetonitrile

The complexes: [Cu(N 3) 2(N,N-diEten)] 2, [Cu(N 3) 2(tmeen)] 2, [Cu(N 3)(NCO)(N,N-diEten)] 2, [Cu(N 3) 2(N,N′-diMeen)] 2 and [Cu(N 3)(NCO)(tmeen)] 2 were prepared, characterized and their electrochemical behavior was investigated by cyclic voltammetry and controlled potential electrolysis. Cyclic voltammograms for all complexes studied are similar and exhibit one pair of current peaks in the range of -0.65 to +0.0 V. The number of electrons obtained from controlled potential electrolysis at ca. -0.55 V for all compounds was 1.8 ≤ n ≤ 2.1, indicating that both copper(II) metallic centres in the molecule were reduced to copper (I). Comparing the peak potential values for these complexes one can observe that the redox process corresponding to copper(II)/copper(I) couple is slightly influenced by the σ-basicity of the ligands. © 1997 Soc. Bras. Química.

Highly excited states for the helium atom in the hyperspherical adiabatic approach

The hyperspherical adiabatic approach is used to obtain the highly excited series 1sns 1S e and 1s(n + 1)p 1P o of the helium atom. The introduction of appropriate asymptotic conditions at large values of the hyperspherical radius results in a stable algorithm that allows the calculation of the full atomic spectrum with precision of a few parts per million. Comparison with the variational calculations available in the literature shows that the accuracy of the results improves with increasing principal quantum number. We present the energies up to n = 31 which is the typical value used in multiphoton excitation experiments.

Utilizing the CORBA platform in the construction of a highly immersive virtual environment

This article presents the implementation of a distributed system of virtual reality, through the integration of services offered by the CORBA platform (Common Object Request Broker Architecture) and by the environment of development of 3D graphic applications in real time, the WorldToolkit, of Sense8. The developed application for the validation of this integration is that of a virtual city, with an emphasis on its traffic ways, vehicles (movable objects) and buildings (immovable objects). In this virtual world, several users can interact, each one controlling his/her own car. Since the modelling of the application took into consideration the criteria and principles of the Transport Engineering, the aim is to use it in the planning, project and construction of traffic ways for vehicles. The system was structured according to the approach client/server utilizing multicast communication among the participating nodes. The chosen implementation for the CORBA was the Iona's ORBIX software. The performance results obtained are presented and discussed in the end.

Avaliação da atividade mutagênica do resíduo sólido de uma fábrica de confecções de meias e lingerie em ensaios com Salmonella typhimurium

Cancer is one of the most hazardous effects to human health caused by the exposition to chemical agents. The search for new technological solutions in the industrial field led to a rapid increase in the productive sector, causing the workers to be exposed to millions of potentially toxic agents, substances potentially harmful to health. This study presents the mutagenic activity of sweepings from a sock and lingerie factory in Araraquara-Brazil, assayed with Salmonella typhimurium. All the extracts from the factory had mutagenic on activity the YG1024 strain, which is extremely sensitive to detect the mutagenic activity of the arilhydroxilamines, nitroarenes and aromatic amines. The extracts were non-mutagenics for the strains TA100 and TA98. The analysis of the mutagenicity of industrial residues is highly important because employees that participate in the production are directly exposed to those agents, as well as to the environment where the garbage is deposited.

Immune reconstitution in HIV-1 infected patients treated for two years with highly active antiretroviral therapy

The aim of this paper was to evaluate the immune reconstitution of HIV-1 patients subjected to highly active antiretroviral therapy (HAART) for two years or more according to CD 45RA and CD 45RO cell count; determination of IL-2, IFN-γ, IL-4, IL-10 and TNF-α serum levels; CD 4 + T and CD 8 + T lymphocyte count; and plasma viral load (VL) determination. For this purpose, a cross sectional study was carried out in the Tropical Diseases Area, Botucatu School of Medicine, São Paulo State University, UNESP, Botucatu, São Paulo, Brazil. Between June 2001 and April 2002, 37 HIV-1 infected patients were evaluated, 13 with treatment indication but untreated (G1), 9 subjected to HAART for 5-7 months (G2), and 15 treated for two years or more (G3); both treated groups used medication regularly and without failure. Forty-nine normal individuals were studied as controls (GC-1 and GC-2). There was a tendency (p<0.10) for the predominance of two nucleoside reverse transcriptase inhibitors (NRTI) associated with one non-nucleoside reverse transcriptase inhibitor (NNRTI) regimen in G2; and two NRTI associated with a protease inhibitor (PI) in G3. Statistical differences between groups were seen for CD 45RA (G1<[G3=GC-2]; p<0.05) and CD 45RO (G1[G2=G3]; p<0.001), TNF-α serum determination ([G1>G3; G2=intermediate]>GC-1; p<0.001), IL-2 (G1<[G2=G3=GC-1]; p<0.01), IFN-γ ([G1=GC-1]>[GC-2=G3]; p<0.001), IL-4 and IL-10 ([G1=G2=G3]>GC-1; p<0.001), serum cytokine profiles, with a higher proportion of subtype 2 in G1 and mature subtype 0 in G2 and G3 (p<0.005). There was no statistical difference for CD 8 + T lymphocyte counts (G1=G2=G3; p<0.50). Consistency was seen between positive correlations of profile 1 definer cytokines (IL-2 and IFN-γ), CD 45RA and CD 45RO cells, and CD 4 + T lymphocyte counts and between positive correlations of profile 2 definer cytokines (IL-4 and IL-10) with TNF-α, and VL. The negative correlations were also consistent as they expressed the inverse of the positives. The variables with the highest number of correlations were IL-2, IFN-γ, and VL, followed by CD 45RA and CD 45RO cells, and IL-10. The variables with the lowest number of correlations were CD 4 + T and CD 8 + T lymphocytes. The results express the partial but important immune reconstitution in HIV-1 infected individuals with the interference of HAART and the importance of cytokines especially IL-2 and IFN-γ, and CD 45RA and CD 45RO cells as surrogate markers of this reconstitution.

Bezafibrate for the treatment of hypertriglyceridemia in HIV1-infected patients on highly active antiretroviral therapy

The use of highly active antiretroviral therapy (HAART) in HIV-infected patients has been associated with the development of risk factors for cardiovascular diseases (CD) including dyslipidemia and insulin resistance, hypertriglyceridemia being the most frequent metabolic disturbance in these patients. Fibrates are indicated when hypertriglyceridemia is accentuated and persists for over six months. We evaluated the efficacy and safety of bezafibrate for the treatment of hypertriglyceridemia in HIV-infected individuals on HAART. All patients received 400mg/day of bezafibrate and were evaluated three times: Mo (pre-treatment), M1 (one month after treatment), and M2 (six months after treatment). Fifteen adult individuals, eight males and seven females with mean age = 41.2 ± 7.97 years and triglyceride serum levels ≥400mg/dL were included in the study. Smoking, alcohol ingestion and sedentarism rates were 50%, 6.66% and 60%, respectively. Family history of CD, hypertension and diabetes mellitus was reported in 33.3%, 40% and 46.7% of the cases, respectively, while dyslipidemia was reported by only 13.3%. More than half of the patients were using a protease inhibitor plus a nucleotide analog transcriptase inhibitor. Eutrophy and tendency toward overweight were observed at all three study time points. There were significant reductions in triglyceride serum levels from Mo to M1 and from Mo to M2. No significant changes were observed in the serum levels of creatine phosphokinase, hepatic enzymes, CD4 +, CD8 + and viral load. Therefore, bezafibrate seems to be safe and effective for the reduction of hypertriglyceridemia in HIV-infected patients on HAART. © 2006 by The Brazilian Journal of Infectious Diseases and Contexto Publishing. All rights reserved.