Expressão Imuno-histoquímica das proteínas GLUT-1 e HIF-1α em lesões vasculares de mucosa oral

The correct histological diagnosis of vascular lesions in the oral mucosa is critical, especially in defining the treatment and prognosis, as some vascular lesions show spontaneous involution and others do not show such behavior. This study analyzed the expression immunohistochemistry of human glucose transporter protein (GLUT-1), in oral benign vascular tumors and to reclassify such lesions according to with his immunoexpression. In addition, we evaluated the immunohistochemical expression of hypoxia-inducible factor 1 alpha (HIF-1α), the main transcription factor involved in cellular adaptation to hypoxia. We analyzed 60 cases of benign oral vascular tumors: 30 cases with histological diagnosis of HEM and 30 cases of oral pyogenic granuloma (PG). The results of this research showed that of the 30 lesions initially classified as HEM, only 7 showed immuno-positivity for GLUT-1, remaining with the initial diagnosis. The remaining 23 were reclassified as vascular malformation (VM) (13 cases) and PG (10 cases). All cases in the sample with an initial diagnosis of PG were negative for GLUT-1, demonstrating the accuracy of histological diagnosis of these lesions. Concerning to the immunoexpression of HIF-1α, the Mann-Whitney test revealed a statistically significant difference between the cases of GP and MV (p = 0.002), where the median of GP (m=78) was higher than the MV (m=53). Based on these results, this study showed that a histological diagnosis alone is not always sufficient for the correct diagnosis of oral HEM and that HIF-1α participates in the pathogenesis of vascular lesions

Photo-induced electron trapping in indirect bandgap AlxGa1-xAs : Si at low temperature

A variation of photoconductivity excitation with wavelength is applied to Si-doped Al0.56Ga0.44As (indirect bandgap material) for a wide range of temperature. The lower the temperature the lower the photocurrent below 70 K. In the range 13-30 K there is a decrease in the photoconductivity spectrum slightly above the bandgap transition energy, followed by another increase in the conductivity. We interpret these results in the light of existing models and confirm the trapping by the X-valley effective mass state. which is responsible for attenuation of persistent photoconductivity below 70 K. A DX0 intermediate state which has non-negligible lifetime is proposed as responsible for the decrease in the photoconductivity with about 561 nm of wavelength of exciting light, in the investigated 13-30 g range.

Exprassão imuno-histoquímica dos fatores de reabsorção óssea em lesões centrais e periféricas de células gigantes

The Giant Cell Lesions, both the Central Giant Cells Lesions (CGCL) as the Peripheral Giant Cells Lesions (PGCL), correspond to a group of oral lesions that are histologically similar entities; however they show a variable clinical behaviour. The purpose of this study was to compare the immunohistochemical expression of bone resorption factors RANK (Receptor Activator of Nuclear Factor kappa B), RANKL (Receptor Activator of Nuclear Factor kappa B Ligand) and OPG (Osteoprotegerin) between CGCL and PGCL. Additionally, these bone resorption factors were examined in terms of aggressiveness of these lesions. The sample consisted of 61 cases, 30 cases of PGCL and 31 CGCL (16 non-aggressive and 15 aggressive). The analysis was performed by quantification of mononuclear cells (MO) and giant multinucleated cells (CG) immunopositive to anti-RANK, anti-RANKL and anti-OPG antibodies in 10 fields. Moreover, according to the proportion between the amount of cells positive for RANKL and OPG, the cases were categorized into: RANKL>OPG, OPG>RANKL e RANKL=OPG. CGCL showed a higher amount of MO (p=0.002) and total cells (p=0.003) both positives to RANKL compared with the PGCL. Additionally, the CGCL revealed a significant association with the ratio of RANKL>OPG (p=0.001). Analysis of the bone resorption factors revealed no significant differences between aggressive and non-aggressive CGCL (p>0.05). It was observed a positive correlation between the markers themselves, and a negative correlation between lesion size and quantity of OPG positive MO cells (p=0,004) and total cells (p=0,009). Through these results, we suggest that the greatest CGCL resorptive potential compared to the PGCL, may have occurred to the high expression of RANKL. Furthermore differences in the biological behavior of aggressive and non-aggressive CGCL appear to be related to the expression of these bone resorption factors

Nanohardness and contact angle of Si wafers implanted with N and C and Al alloy with N by plasma ion implantation

Surfaces of silicon wafers implanted with N and C, respectively, and aluminum 5052 implanted with N alone by plasma immersion ion implantation WHO were probed by a nanoindentor and analyzed by the contact-angle method to provide information on surface nanohardness and wettability. Silicon nitride and silicon carbide are important ceramic materials for microelectronics, especially for high-temperature applications. These compounds can be synthesized by high-dose ion implantation. The nanohardness of a silicon sample implanted with 12-keV nitrogen PIII (with 3 X 10(17) cm(-2) dose) increased by 10% compared to the unimplanted sample, in layers deeper than the regions where the formation of the Si,N, compound occurred. A factor of 2.5 increase in hardness was obtained for C-implanted Si wafer at 35 keV (with 6 X 10(17) cm(-2) dose), again deeper than the SiC-rich layer, Both compounds are in the amorphous state and their hardness is much lower than that of the crystalline compounds, which require an annealing process after ion implantation. In the same targets, the contact angle increased by 65% and 35% for N- and C-implanted samples, respectively. Compared to the Si target, the nitrogen PIII-irradiated Al 5052 (wish 15 keV) showed negligible change in its hydrophobic character after ion implantation. Its near-surface nanohardness measurement showed a slight increase for doses of 1 X 10(17) cm(-2). We have been searching for an AlN layer of the order of 1000 A thick, using such a low-energy PIII process, but oxide formation during processing has precluded its synthesis. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Structural Evaluation of Mechanically Alloyed and Heat-Treated Ti-25at-%Si Powders

This work discusses on the structural evaluation of mechanically alloyed and heat-treated Ti-25at%Si powders. The milling process was conducted in a planetary ball mill using stainless steel balls/vials, 200 rpm and ball-to-powder weight ratio of 5:1, whereas the heat treatment was conducted under Ar atmosphere at 1100 C for 4 h. Samples were characterized by X-ray diffraction, differential scanning calorimetry, scanning electron microscopy and energy dispersive spectrometry. The Si peaks disappeared after milling for 30h, indicating that the Si atoms were dissolved into the Ti lattice in order to form an extended solid solution. The Ti peaks were broadened and their intensities reduced for longer milling times whereas a halo was formed in Ti-25Si powders milled for 200h suggesting that an amorphous structure was achieved. The crystallite size was decreased with increasing milling times. A large Ti3Si amount was found in mechanically alloyed Ti-25at%Si powders after heating at 1100 degrees C for 4h.

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.

Effect of oxidizing atmosphere on the electrical properties of SrBi4Ti4O15 thin films obtained by the polymeric precursor method

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

Enhanced ferroelectric properties of La-substituted BiFeO3 thin films on LaSrCoO3/Pt/TiO2/SiO2/Si (100) substrates prepared by the soft chemical method

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Synthesis of slightly < 111 >-oriented 0.65Pb(Mg1/3Nb2/3)O-3-0.35PbTiO(3) ceramic prepared from fine powders

Slightly < 111 >-oriented 0.65Pb(Mg1/3Nb2/3)03-0.35PbTiO(3) ceramic was prepared using fine powders obtained by means of an alternative and promising chemical oxide precursor method. High quality samples with improved structural, microstructural, dielectric and ferroelectric properties were obtained. The dielectric constant value (epsilon similar to 2577) measured at 1 kHz is compared to unpoled < 112 > grain-oriented ceramics while the remanent polarization (P-r similar to 19-1 mu cm(-2)) is compared with random grain-oriented ceramics. These results point out the viability to produce ferroelectric PMN-PT ceramics of very good quality using powder precursors prepared from this chemical method. (c) 2007 Elsevier B.V. All rights reserved.

Radiative association of C and P, and Si and P atoms

The rate coefficients for the formation of carbon monophosphide (CP) and silicon monophosphide (SiP) by radiative association are estimated for temperatures ranging from 300 to 14 100 K. In this temperature range, the radiative association rate coefficients are found to vary from 1.14 x 10(-18) to 1.62 x 10(-18) cm(3) s(-1) and from 3.73 x 10(-20) to 7.03 x 10(-20) cm(3) s(-1) for CP and SiP, respectively. In both cases, rate coefficients increase slowly with the increase in temperature.

Electrical conductivity of silicate glasses with tetravalent cations substituting Si

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

Preparation of different basic Si-MCM-41 catalysts and application in the Knoevenagel and Claisen-Schmidt condensation reactions

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Improvement of fatigue resistance on La modified BiFeO(3) thin films

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Very Intense Distinct Blue and Red Photoluminescence Emission in MgTiO3 Thin Films Prepared by the Polymeric Precursor Method: An Experimental and Theoretical Approach

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evaluation of Lubricating Oil Preparation Procedures for the Determination of Al, Ba, Mo, Si and V by High-Resolution Continuum Source FAAS

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