Propriedades ópticas de nanopartículas de halogenetos de cobre preparadas in situ em filmes híbridos de sílica

The sol-gel process is a technique based on the hydrolysis and polycondensation of metal alkoxides have been investigated as an alternative for the preparation of vitreous or glassceramic materials, for allowing the obtaining of high-purity materials at low temperatures, and to obtain hybrid materials with different compositions. When ORMOSILs are doped with nanoparticles, are called nanocomposites, and its functionality arises when electrons confined in scale three-dimensional structures near zero are excited. In principle, such materials exhibit discrete energy level, with peaks in the absorption spectrum. Therefore, the glasses doped semiconductor nanocrystals are important candidates for the preparation of optical filters with sharp cut-off, and are being exploited commercially for coloring glasses. This study evaluates the optical properties presented by hybrid films of silica doped with copper nanoparticles. The matrix was prepared using the alkoxides 3-glycidoxypropyltrimethoxysilane (GPTS) and tetraethylorthosilicate (TEOS) doped with Cu2O and hydrolyzed under reflux conditions in two different acidic conditions (HCl and HBr). After thermal treatment at temperatures between 100 °C and 170 °C and/or under the action of commercial black light radiation, CuCl and CuBr present in the hybrid film are transformed into nanoparticles of CuCl or CuBr. The UV-VIS absorption identified the absorption bands, and its variation

Propriedades ópticas e elétricas de materiais híbridos de sílica/orgânico à base de GPTS:TEOS preparados pelo método sol-gel

Fabrication of optoelectronic devices requires the employment of at least one transparent electrode. Usually, commercially transparent electrodes have been made by deposition of indium tin oxide (ITO) films by RF-Sputtering technique. These commercial electrodes have sheet resistance of about 100 Ω/sq and optical transmittance of 77% at the wavelength of 550 nm. The poly(3,4-ethylenedioxythiophene):polystyrene-sulfonate (PEDOT:PSS) is an alternative material to fabricate transparent electrodes due to its high conductivity (about 600 S/cm) and solubility in water. Soluble conductive materials exhibits advantages for processing of electrode layers, however there is a disadvantage during devices fabrication once materials with the same solvent of the electrode material cannot be coated one over the other. Alternatively, organic/Silica hybrid materials prepared by sol-gel process allow producing bulks and films with high chemical durability. In order to obtain transparent electrodes with high chemical durability, we introduced a blended material comprising the high UV-VIS transparency of organic/Silica sol-gel material and a high conductivity polymer PEDOT:PSS. The organic/Silica sol was obtained using two different molar concentrations (1:1 and 4:1), of tetraethylorthosilicate (TEOS) and 3-glycidoxypropyltrimethoxysilane (GPTS). Amounts of PEDOT:PSS solutions were added to the sol material, resulting in different weight fractions of sol and polymer. G:T/P:P were deposit onto glass substrates by spray-coating. In order to perform electrical characterization of the blended material, gold electrodes were thermally evaporated onto the films. The electrical characterization was performed using a Keithley 2410 source/meter unity and the optical characterization, using a Cary50 UV-Vis spectrophotometer. The absorption coefficient and electric conductivity of the different compositions blends, as function of the PEDOT:PSS concentration, were...

Detecção de genes de entrotoxinas de Staphylococcus aureus e estafilococos coagulase negativos isolados de leite bovino e de tanques de refrigeração comunitários procedentes de pequenas propriedades da região de Bauru-SP

Pós-graduação em Medicina Veterinária - FMVZ

Estudo da influência da cinza de casca de arroz e da cal nas propriedades do solo-cimento auto-adensável

Pós-graduação em Engenharia Civil - FEIS

Estudo da situação epidemiológica da brucelose e tuberculose bovina em propriedades fornecedoras de leite para o programa Laticínio Escola do município de Botucatu-SP

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

Estudo do efeito da cristalinidade nas propriedades mecânicas de compósitos termoplásticos com aplicações aeronáuticas

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

Caracterização microestrutural e propriedades mecânicas em pinos para transmissão mecânica de aço inoxidável martensítico e pinos fusíveis de latão em chave de alta tensão

Pós-graduação em Engenharia Mecânica - FEB

Propriedades estatísticas de bilhares abertos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo das propriedades físicas de sistemas ferroelétricos com estruturas tipo Aurivillius

Pós-graduação em Ciência dos Materiais - FEIS

Efeitos da administração em longo prazo do omeprazol sobre a densidade mineral óssea e as propriedades mecânicas do osso

Objectives: Epidemiological studies have shown a relationship between long-term use of proton pump inhibitors and bone metabolism. However, this relationship has not yet become established. The aim of the present study was to analyze the mechanical properties and bone mineral density (BMD) of rats that were subjected to long-term omeprazole use. Methods: Fifty wistar rats weighing between 200 and 240 g were divided equally into five groups: OMP300 (omeprazole intake at a dose of 300 moL/kg/day); OMP200 (200 moL/ kg/day); OMP40 (40 moL/kg/day); OMP10 (10 moL/kg/day); and Cont (control group; intake of dilution vehicle). The solutions were administered for 90 consecutive days. After the rats had been sacrificed, their BMD, the mechanical properties of the dissected femurs and their serum Ca++ levels were analyzed. Results: The BMD of the OMP300 group was lower than that of the controls (p = 0.006). There was no difference in comparing the OMP200, OMP40 and OMP10 groups with the controls. The maximum strength and rigidity of the femur did not differ in the experimental groups in comparison with the controls. The OMP300 group had a statistically lower serum Ca++ concentration than that of the controls (p = 0.049), but the other groups did not show any difference in relation to the controls. Conclusion: Daily intake of 300moL/kg/day of omeprazole decreased the BMD of the femur, but without changes to the rigidity and strength of the femur in adult rats. © 2

Cerâmicas odontológicas: propriedades, indicações e considerações clinicas

The demand for esthetic restorations has resulted in an increased use of dental ceramics and is the main alternative restorative material to tooth structure due to its favorable properties. Therefore, the aim of this work is to study the evolution of ceramic systems, involving different types and properties, indications, and clinical issues as aesthetic, cementing and longevity. In a detailed and advanced search in the database PubMed, 98 articles were found using the following key words: dental porcelain dental all-ceramic and ceramic according to the criteria for inclusion and exclusion left only 35 articles for review. Several ceramic systems are available in the market, making the prosthetic professionals need a constant recycling about their properties and directions, since good results are due to the selection of the best material for a particular case in all the skill of the practitioner.

Avaliação da composição química, proteólise e propriedades funcionais do queijo mussarela comercial com teor reduzido de gordura

Chemical composition, proteolysis and functional properties of commercial Mozzarella cheese with reduced fat content found in the market of Londrina – PR were evaluated. The cheeses were analyzed for chemical composition, meltability, free oil formation, and the indexes of extension and depth of proteolysis during 30, 45 and 60 days of storage at 5°C. The samples showed no significant difference in chemical composition. The fat content of all samples complied with current legislation regarding the minimum percentage (25%) of fat reduction. Among the three brands tested, the cheeses of brand C showed the highest depth index of proteolysis. In all chesses, the meltability has increased during storage period. The, the brand C had significantly higher (p <0.05) free oil content when compared to other brands tested.

Propriedades elétricas de materiais híbridos de Sílica/orgânico à base de GPTS/TEOS preparados pelo método sol-gel

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)