Structural and electrical properties of SrBi2(Ta0.5Nb0.5)(2)O-9 thin films

SrBi2(Ta0.5Nb0.5)(2)O-9 (SBTN) thin films were obtained by polymeric precursor method on Pt/Ti/SiO2/Si(1 0 0) substrates. The film is dense and crack-free after annealing at 700 degrees C for 2 h in static air. Crystallinity and morphological characteristic were examined by X-ray diffraction (XRD), field emission scanning electron microscopy (FEG-SEM) and atomic force microscopy (AFM). The films displayed rounded grains with a superficial roughness of 3.5 nm. The dielectric permittivity was 122 with loss tangent of 0.040. The remanent polarization (P-r) and coercive field (E-c) were 5.1 mu C/cm(2) and 96 kV/cm, respectively. (C) 2007 Published by Elsevier B.V.

Preparation of 9.5/65/35 PLZT powders by organic precursor method

In this study the preparation of 9.5/65/35 PLZT ceramic powders were investigated. The powders with the formula Pb0.905La0.095(Zr0.65 Ti0.35)0.976O3 + 3.5 w% PbO were prepared using Pechini process and partial oxalate method. The powder phase formation, powder morphology, and green density of PLZT were shown.

Gingival margin alterations and the pre-orthodontic treatment amount of keratinized gingiva

The purpose of this retrospective study was to associate the amount of keratinized gingiva present in adolescents prior to orthodontic treatment to the development of gingival recessions after the end of treatment. The sample consisted of the intra-oral photographs and orthodontic study models from 209 Caucasian patients with a mean age of 11.20 ± 1.83 years on their initial records and 14.7 ± 1.8 years on their final records. Patients were either Angle Class I or II and were submitted to non-extraction orthodontic treatment. Gingival recession was evaluated by visual inspection of the lower incisors and canines as seen in the initial and final study models and intra-oral photographs. The amount of recession was quantified using a digital caliper and the observed post-treatment gingival margin alterations were classified as unaltered, coronal migration of the gingival margin or apical migration of the gingival margin. The width of the keratinized gingiva was measured from the mucogingival line to the gingival margin on the pre-treatment photographs. The teeth that developed gingival recession and those that did not have their gingival margin position changed did not differ in relation to the initial amount of keratinized gingiva (3.00 ± 0.61 and 3.5 ± 0.86 mm, respectively). Paradoxically, teeth that presented a coronal migration of the gingival margin had a smaller initial amount of keratinized gingiva (2.26 ± 0.31 mm). The mean amount of initial keratinized gingiva did not predispose lower incisors and canines to gingival recession.

Macroeconomía, comercio y finanzas para reformar las reformas en América Latina

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Effect of weathering and thickness on roughness of acrylic resin and ocular button

Purpose: The aim of this study was to evaluate the roughness of colorless ocular button and four brands of colorless acrylic resins designed to fabricate ocular prosthesis as a function of weathering (1008 h) and different thickness (1 and 3.5 mm). Materials and methods: One-hundred-and-twenty specimens were fabricated and distributed in 12 groups. The analysis was carried out by means of digital roughness meter. Results: Data were analyzed statistically by ANOVA and Tukey test at 1% significance. The results showed that there was no statistically significant difference after the weathering period. Both the Vipi Cril acrylic resin with 3.5 mm in thickness and ocular button with 1 mm in thickness presented the lowest roughness values (0.12. Ra). Conclusion: The roughness of the acrylic resins and the ocular button was not affect by the weathering of 1008 h. However, the thickness of the specimens proved to have a major influence on roughness property. © 2010.

Laser stimulated light reflection for TeO2-WO 3-Bi2O3 thin films with incorporated Si nanoparticles

A novel method of preparation of the Si nanoparticles (NPs) incorporated in tellurite TeO2-WO3-Bi2O3 (TWB) thin films is proposed. This mew method applies RF magnetron sputtering technique at room temperature. The incorporation of Si NP was confirmed by transmission electron microscopy (TEM); isolated Si NPs with diameters of around 6 nm are observed. Energy dispersive X-ray spectroscopy (EDS) was performed during TEM analysis in order to confirm the presence of Si NP and also the other elements of the thin film. The thin films are explored with respect to the photoinduced changes of the reflectivity within the 400-65 nm spectra range using a 10 ns pulsed Nd:YAG with power densities varying up to 400 MW/cm2 and beam diameter within the 3-5 mm range. The observed processes are analyzed within a framework of trapping level conceptions for the Si NP. The possible application of the discovered materials as optical sensitive sensors is proposed. © 2013 Elsevier B.V.

El crecimiento de la población y la expansión del Area Urbana en el Area Metropolitana de Medellín

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Desempenho de sistema de diagnóstico óptico para detecção de lesões de cárie

Pós-graduação em Ciências Odontológicas - FOAR

Atividade antimicrobiana in vitro de extratos hidroetanólicos de Astronium sp incorporados ou não em sistemas nanoestruturados

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estado nutricional de couve-flor ‘Verona’ submetida à omissão de macronutrientes

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Efeito de compensação de cargas nas propriedades luminescentes dos materiais 'BA''WO IND.4':'EU POT.3+','LI POT.+'

Pós-graduação em Química - IQ

Estudo sobre o uso do pentacloreto de nióbio em reações multicomponentes para síntese de derivados de 4-ARIL-3,4-DI-Hidrocumarinas

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Avaliação eletrorretinográfica de ratos wistar jovens submetidos à tireoidectomia bilateral

A tireoide sintetiza a tiroxina (T4) e a 3,5,3’-triiodotironina (T3), ambos hormônios apresentam uma função crucial no desenvolvimento do sistema nervoso central, incluindo o sistema visual e a retina. A diminuição dos níveis sanguíneos do T3 e T4 ocasionam uma síndrome denominada de hipotireoidismo, o que pode levar à prejuízos visuais. Os déficits visuais gerados pelo hipotireoidismo estão diretamente relacionados ao período de desenvolvimento do indivíduo. Foi demonstrado em modelos murinos que o hipotireoidismo congênito diminui a espessura da retina, o número de células, e interfere na diferenciação da subpopulação de cones M. Desta forma buscaremos investigar possíveis alterações funcionais na retina de ratos wistar jovens após a tireoidectomia bilateral, utilizando respostas eletrofisiológicas não invasivas. Para tanto, dividimos os ratos em três grupos (controle, sham e tireoidectomizado) cada um contendo ≥ 8 animais. As cirurgias foram realizadas 30 dias pós-natal. Os eletrorretinogramas de campo total foram realizados 10, 15, 20, 25 e 30 dias após a cirurgia, utilizando protocolos para avaliar a resposta escotópica máxima, resposta fotópica (com e sem o uso de filtros de luz) e a resposta ao flicker (12, 15, 18 e 30 Hz). Os parâmetros analisados foram o tempo implícito e a amplitude das ondas a e b. Além disso, realizamos o monitoramento dos parâmetros clínicos dos animais, visando identificar características que indiquem um quadro de hipotireoidismo, bem como a dosagem dos hormônios tireoidianos. Os resultados obtidos demonstraram que em todos dos protocolos de estimulação utilizados no ERG houve diminuição nas amplitudes das ondas a e b nos animais tireoidectomizados em todos os dias avaliados após a cirurgia, quando comparados com animais do grupo controle e sham. Os resultados da avaliação do tempo implícito para ambas as ondas não demonstraram diferença estatística quando comparamos os diversos grupos ao controle. Também podemos constatar uma redução do ganho de peso e tamanho nos animais que sofreram tireoidectomia, associados à redução dos níveis de hormônio tireoidiano (T3). Concluímos dessa forma que os hormônios tireoidianos estão diretamente ligados a alterações funcionais na retina dos animais que sofreram tireoidectomia, bem com, na redução da aquisição de peso e aumento de tamanho.

Interferência da redução no volume de aplicação sobre o controle da mancha preta (Guignardia citricarpa Kiely) em frutos de laranja 'Valência'

The chemical control of the causal agent of citrus black spot (CBS) has been highlighted for the excessive required number of sprayings, considerably increasing citrus production costs. Improvements in the spray efficiency and reductions in the quantity of phytosanitary products have already been searched, but the results of that practice are not consistent yet for its use at commercial scale. Thus, the aim of the present study was to evaluate the interference of reduced spray volumes in black spot control in citrus fruits. The experiment was carried out in commercial citrus orchard with 16-year-old plants of 'Valencia' variety, during 2007 agricultural season. Treatments consisted of three spray volumes: 3.5; 4.5 and 8.5 liters.plant-1, applied with Arbus 2000/Export airblast sprayer with special manifold of hydraulic nozzles, using fungicides and periods recommended for the disease control, totaling four sprayings plus a control treatment (without spray). The disease incidence and severity were evaluated by visual diagrammatic scale of notes in two different periods (preharvest and harvest), at three plant heights (low, middle and top) and three horizontal sections (entrance, frontal and exit) in two sides of the plant. The fallen fruits were counted every fifteen days, for previously selected plants, from the beginning of maturation to harvest, and the production was quantified (kg.plant-1). The disease incidence and severity were significantly lower when sprayings were done with 8.5 liters.plant-1 in the first evaluation period (pre-harvest), but in the harvest period there were not differences between the same parameters when 4.5 or 8.5 liters.plant-1 were sprayed. None of those treatments reduced the disease on the top section of plants, compared to control. The plant sections with fruits more exposed to sun rays, top and right side of the plant, demonstrated higher disease incidence and severity. The volume reduction from 8.5 to 4.5 liters.plant-1 can be adopted for citrus orchards without damaging the CBS control level.

Synthesis and thermal behavior study of complexes of the type [Pd(mu-X)(4-eb-p-phen)](2) (X = Cl, Br, I, N-3, NCO, SCN) and 4-eb-p-phen [bis(4-ethylbenzyl)p-phenylenediimine]

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