Influence of a co-substituted A-site on structural characteristics and ferroelectricity of (Pb, Ba, Ca)TiO3 complex perovskites: analysis of local-, medium- and long-range order

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

Structure and catalytic properties of sulfated zirconia foams

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

Chitosan/(ureasil-PEO hybrid) blend for drug delivery

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of Zn2+ ions on the structure, morphology and optical properties of CaWO4 microcrystals

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Preparation and characterization of PEG-coated silica nanoparticles for oral insulin delivery

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

Unusual broadening of the NIR luminescence of Er3+-doped Nb2O5 nanocrystals embedded in silica host: Preparation and their structural and spectroscopic study for photonics applications

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

Production and characterization of natural rubber-Ca/P blends for biomedical purposes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Pluronics F-127/L-81 Binary Hydrogels as Drug-Delivery Systems: Influence of Physicochemical Aspects on Release Kinetics and Cytotoxicity

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

Development of organic-inorganic polymeric film formers for controlled drug release and wound care

Film forming polymeric systems represents a new and unexplored technology of systems forskin or wounds protection and for controlled drug release. The aim of this work was to study the use of polymeric organic-inorganic ureasil-polyether hybrids synthesized by the sol-gel process as film forming system containing silver sulfadiazine as model drug. The film formationtime can be controlled by changing the precursor/catalyst ratio used during the step of hydrolysis and condensations. The results showed that the precursor/catalyst proportion influences both the visual characteristics and time required to form the film. The precursor/catalyst ratio equal to 20.8 m/v was considered ideal due to promote the homogeneous and transparent film formation in less than 5 minutes. The release profile of sulfadiazine is dependent on the characteristics of the matrixes: matrix more hydrophobic as ureasil-POP provided a slowed released mainly due to the low swelling of the matrix. The more hydrophilic ureasil-POE matrix presents a large capacity to swell and favors the faster release of the drug. The set of results showed the possibility of future use of these systems for treating wounds caused by burns.

Estudo do potencial de associações de ZnO com os produtos naturais ácido cafeico e ferúlico como filtros solares híbridos: [recurso eletrônico]

In this work were studied associations of ZnO with the natural products caffeic and feluric acids. Two preparation methods were used, that is, the sol-gel and a reflux procedure. In the sol-gel method, ZnO is produced by the basics hydrolysis of precursors in the presence of the organic filters (caffeic and feluric acids), which results in 30 nm (or less) ZnO particles with the organic filters (in dissociated form) bonded to the surface of ZnO. In the reflux method, a dispersion of ZnO in a water/ethanol mixture was kept under reflux (50oC/4h) in the presence of the organic acids. The ZnO particles used in the reflux method have a higher diameter than sol-gel ZnO particles, but the prepared associated product ZnO/Organic acids were similar. Despite of the difference in relation to crystallinity between the products, the preparation methods resulted in analogous associations with respect to the interaction of the organic filters with the ZnO surface. The caffeic/ZnO associations presented low photostability, which lead to the degradation of the organic filter. The other associations (feluric acid/ZnO) presented satisfactory results. The FT-IR spectroscopy confirmed the formation of the association, and the nature of the bond formed compared with the Zn-O bond in Zn2+/Felutic acid complexes. The isolated organic and inorganic filters, along with the associations were analyzed by diffuse reflectance spectroscopy and Uv-vis spectroscopy. The absorption edges and the critical wavelengths were analyzed and the effects of Zn-O bonds in feluric acid/ZnO associations described as a function of the relative position of the π/π* system of the organic filter. Finally the performance of the hybrid filters were investigated in terms of the absorption of UVA and UVB radiations, with the UVA/UVB ratio, an efficiency parameter largely used in the description of solar filters, sunscreen and suncare products

Efeitos fotocrômico e termocrômico em ormosils dopados com azobenzenos

The sol-gel process and the wide variety of alkoxides commercially available have facilitated the processing of various Organic-Inorganic Hybrid Materials. In general, the hybrids are excellents matrix to incorporate organic or inorganic dopants that presents photochromic, thermochromic, and halochromic effects and in some cases photorefractive effects. The GPTS-TEOS hybrid matrix when deposited in the form of film is very resistant, adherent, has excellent transparency in visible region and allows to be doped with various azo-dye and metal salts of unusual oxidation states. One of the main characteristics of the azo-dyes when immersed in some hybrid matrix , is the capacity to isomerizes through group Azo (-N = N-) would can be commutated between the Cis (Z) and Trans (E) configurations by means of light or heat. Our goal was through the sol-gel process to prepare hybrid films of GPTS-TEOS doped with azo-dyes Methyl Red and Disperse Red 1, and characterize them optically. The characterizations are performed using techniques of UV / Vis spectroscopy, to identify changes in the absorption band of azo-dyes in the presence of optical pumping, (photochromic effects), in function of temperature (thermochromic effect). These properties are of wide scientific and technological interest because they will contribute to the confection Smart Windows (windows sensible to light), temperature sensors monitored optically and also in the recording of amplitude and phase diffraction gratings

Modificação da superfície do titânio e de sua liga Ti-6Al-4V por recobrimento com TiO2 e hidroxiapatita

In this work, the influence of modifications of the cp-Ti and Ti 6Al 4V alloy, by treating the surface with NaOH and depositing titanium oxide and hydroxyapatite by sol-gel method, on their biocompatibility was studied. The coatings were characterized by scanning electron microscopy and X-ray diffraction which showed that the coatings on Ti 6Al 4V are better than on cp-Ti. Adhesion tests showed that adhesion strength of the coatings on cp-Ti substrate is less than on Ti 6Al 4V as well as cytotoxicity for L929 fibroblast cells is higher

Cinética de hidrólise de GPTS sob estimulação ultrassônica

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação da influência da esterilização por radiação gama nas propriedades mecânicas, estruturais e na biocompatibilidade de matrizes híbridas orgânico-inorgânicas

Atualmente, as pesquisas acadêmicas e industriais não estão voltadas apenas para a descoberta de novos fármacos, mas também para novas maneiras de administração de medicamentos pretendendo obter melhores ações farmacológicas alem de reduzir efeitos colaterais. Partindo deste pressuposto, estudos demonstram que inúmeras moléculas podem ser incorporadas a polímeros híbridos orgânico-inorgânico preparados pelo processo sol-gel, assim pretende-se estudar a possibilidade de sua aplicação no desenvolvimento de um dispositivo de liberação controlada de fármacos na forma de implantes subcutâneos. As matrizes hibridas para serem implantadas devem, necessariamente, ser estéreis. Para isto este trabalho analisa a interação entre o processo de esterilização e uma provável alteração estrutural nestes polímeros. A esterilização por calor úmido em autoclave e a esterilização por radiação gama foram escolhidas para analisar a correlação entre alteração estrutural do hibrido e o processo de eliminação de microorganismos. Outro aspecto que levamos em consideração foi a melhora das características mecânicas das matrizes poliméricas confeccionadas com poli óxido etileno de peso molecular 1900 (POE 1900) e poli óxido propileno de peso molecular 400 (POP 400). Para serem implantadas estas matrizes devem estar uniformes, e não podem trincar ou quebrar antes ou após a implantação. Considerando estes fatores foi adicionado as amostras um agente plastificante, o álcool polivinílico (PVA), na tentativa de melhorar estas características