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Wastewater treatment targeting reuse may limit water scarcity. Photocatalysis is an advanced oxidation process that may be employed in the removal of traces of organic pollutants, where the material choice is important. Titanium dioxide (TiO2) is a highly efficient photocatalyst with good aqueous stability. TiO2 powder has a high surface area, thus allowing good pollutant adsorption, but it is difficult to filter for reuse. Thin films have a significantly lower surface area but are easier to regenerate and reuse. In this paper, we report on obtaining sol-gel TiO2 thin films on spherical beads (2 mm diameter) with high surface area and easy recovery from wastewater. The complex influence of the substrate morphology (etched up to 48 h in concentrated H2SO4), of the sol dilution with ethanol (1:0 or 1:1), and the number of layers (1 or 2) on the structure, morphology, chemical composition, and photocatalytic performance of the TiO2 thin films is investigated. Etching the substrate for 2 h in H2SO4 leads to uniform, smooth surfaces on which crystalline, homogeneous TiO2 thin films are grown. Films deposited using an undiluted sol are stable in water, with some surface reorganization of the TiO2 aggregates occurring, while the films obtained using diluted sol are partially washed out. By increasing the film thickness through the deposition of a second layer, the roughness increases (from ~50 nm to ~100 nm), but this increase is not high enough to promote higher adsorption or overall photocatalytic efficiency in methylene blue photodegradation (both about 40% after 8 h of UV-Vis irradiation at 55 W/m2). The most promising thin film, deposited on spherical bead substrates (etched for 2 h in H2SO4) using the undiluted sol, with one layer, is highly crystalline, uniform, water-stable, and proves to have good photocatalytic activity.

Made available in DSpace on 2016-07-01T13:10:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-08-13. Added 1 bitstream(s) on 2016-07-01T13:13:45Z : No. of bitstreams: 1 000866002.pdf: 1774918 bytes, checksum: 7a85fafd4477aa0f0f75ad8c323e976f (MD5) Os tumores mamários constituem a neoplasia mais comum das cadelas, sendo que mais da metade são consideradas malignas e com muitos animais apresentando morte associada à doença. Estes tumores geralmente são tratados cirurgicamente por meio de mastectomia, porém os resultados frequentemente não são satisfatórios. Visto que novas abordagens terapêuticas são necessárias nos tumores mamários caninos, especialmente no que diz respeito ao tratamento adjuvante e à terapia alvo, o conhecimento acerca de possíveis componentes relacionados com a resistência à fármacos e que funcionem como possíveis alvos moleculares para a terapia deve ser garantido. Em vista disso, o objetivo da pesquisa descrita nesta tese foi caracterizar o papel da família de receptores do fator de crescimento epidermal (EGFR) e da superfamília de transportadores ligadores de ATP (ABC) nos tumores mamários caninos como biomarcadores do câncer e sua relação com o desfecho da doença para caracterizar sua patobiologia. Neste estudo, os receptores tirosina cinase EGFR/HER1, HER2, HER3 e HER4, assim como as proteínas da família ABC glicoproteína-P/MDR1, MRP1 e MRP2 foram avaliadas por meio de imunoistoquímica, sendo os resultados relacionados com características clinicopatológicas em 43 tumores. A expressão simultânea de todos os membros da família e a coexpressão de EGFR/HER1, HER2 e HER4 se mostraram associadas com um desfecho desfavorável para a doença. A expressão de glicoproteína-P e MRP1 se apresentaram relacionadas com características clinicopatológicas nos tumores estudados, ao passo que a expressão de MRP1 foi caracterizada como um indicador prognóstico independente nestes tumores. Em síntese, esta tese fornece novas informações acerca da expressão da família EGFR nos tumores mamários caninos e associa os transportadores ABC com um desfecho desfavorável para a doença, consequentemente sugerindo que eles também podem estar... Mammary tumors comprise the most common neoplasms in female dogs with more than half with malignat characteristics. Such tumors are usually treated using surgical mastecty, but results are frequently not satisfying. Since new therapeutical approaches are needed in canine mammary tumors, especially regarding adjuvant therapy and targeted therapy, an understanding regarding possible cellular components related to drug resistance and that work as possible targets for therapy is straightforward to achieve. Accordingly, the aim of the research described in this thesis was to study the possible role of epidermal growth factor receptor family (EGFR) and ATP-binding cassete (ABC) superfamily members in canine mammary tumors as cancer biomarkers and its relation with disease outcome in order to better characterize their pathobiology looking forward the future improve in canine mammary cancer treatment. In this study, tyrosine kinase receptors EGFR/HER1, HER2, HER3, and HER4, as well ABC transporters P-glycoprotein/MDR1, MRP1, and MRP2 were immunohistochemically evaluated and results were related with clinicopathologic characteristics and overall survival in 43 tumors. Expression of all family members and simultaneous expression of EGFR/HER1, HER2, and HER4 were related with a poor disease outcome. P-glycoprotein and MRP1 expression showed to be related with clinicopathologic features and MRP1 was characterized as a independent prognostic indicator in such tumors. In summary, this thesis provides new information about EGFR family expression in canine mammary tumors and associates ABC transporters with a poor disease outcome, consequently suggesting that they may also be related to prognosis in patients with mammary cancer