Interface Formation and Electrical Transport in SnO2:Eu3+/GaAs Heterojunction Deposited by Sol-Gel Dip-Coating and Resistive Evaporation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Cyclodextrin glycosyltransferase production by new Bacillus sp. strains isolated from brazilian soil

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

Photocatalytic Degradation of Phenol by Thermal Titanium Dioxide Thin Layer Electrodes

Electrochemical processes in industrial effluents have been studied as a means to obtain higher efficiency in wastewater treatment. Heterogeneous photocatalysis appears as a low-cost alternative through the use of lower wattage lamps and thermal TiO2 films. Photocatalysis became a clean process for water treatment due to hydroxyl radicals generated on semiconductor surface. Such radicals are able to degrade several organic compounds. This study used different electrodes and analytical methods for degradation of phenol molecules to reduce treatment costs, improve efficiency, and identify compounds formed during the decomposition of phenolic molecules. Thermal growth of TiO2 film was observed on the titanium electrode in rutile form. Application of an electrical potential on the Ti/TiO2 working electrode increases efficiency in reducing concentration of phenol after photocatalytic treatment. Still, high energy radiation (UVC) showed best degradation rates in photolytic process. Different compounds formed during the degradation of phenol were also identified in the UVC-PE treatment.

Application of abrupt cut-off models in the analysis of the capacitance spectra of conjugated polymer devices

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

Production of cyclodextrins by CGTase from Bacillus clausii using different starches as substrates

Cyclodextrins ( CDs) are cyclic oligasaccharides composed by D- glucose monomers joined by alpha- 1,4-D glicosidic linkages. The main types of CDs are alpha-,beta-and gamma-CDs consisting of cycles of six, seven, and eight glucose monomers, respectively. Their ability to form inclusion complexes is the most important characteristic, allowing their wide industrial application. The physical property of the CD-complexed compound can be altered to improve stability, volatility, solubility, or bio-availability. The cyclomaltodextrin glucanotransferase ( CGTase, EC 2.4.1.19) is an enzyme capable of converting starch into CD molecules. In this work, the CGTase produced by Bacillus clausii strain E16 was used to produce CD from maltodextrin and different starches ( commercial soluble starch, corn, cassava, sweet potato, and waxy corn starches) as substrates. It was observed that the substrate sources influence the kind of CD obtained and that this CGTase displays a beta- CGTase action, presenting a better conversion of soluble starch at 1.0%, of which 80% was converted in CDs. The ratio of total CD produced was 0: 0.89: 0.11 for alpha/beta/gamma. It was also observed that root and tuber starches were more accessible to CGTase action than seed starch under the studied conditions.

Short-term successional dynamics of a macroalgal community in a stream from northwestern São Paulo State, Brazil

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

Doping saturation in dye-sensitized solar cells based on ZnO:Ga nanostructured photoanodes

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

The interaction between atoms of Au and Cu with clean Si(111) surface: A study combining synchrotron radiation grazing incidence X-ray fluorescence analysis and theoretical calculations

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Schottky-type grain boundaries in CCTO ceramics

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

Multi-functional properties of CaCu3Ti4O12 thin films

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

Espectroscopia de impedância eletroquímica aplicada ao estudo das reações heterogêneas em ânodos dimensionalmente estáveis

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

Efeitos da adição de átomos de Mn na rede do GaN via métodos de estrutura eletrônica

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

Avaliação da limpeza de CDtrodo construídos a partir de CD de ouro gravável/fita adesiva de galvanoplastia

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

FÉCULA E FARELO DE MANDIOCACOMO SUBSTRATO NA PRODUÇÃO DE CICLODEXTRINAS

Ciclodextrinas (CDs) são oligossacarídeos cíclicos, não redutores, capazes de formar complexos de inclusão com outras moléculas, modificando suas características químicas e físicas. São de interesse industrial, mas o fator limitante para sua utilização ainda é o alto custo de produção. Devido à sua pureza e ao teor de amilopectina, a fécula de mandioca se apresenta como substrato potencial para a produção de CDs, tendo mais de 95% de amido. Outro substrato potencial é o farelo, resíduo da extração da fécula de mandioca, com cerca de 70% de amido e custo consideravelmente inferior ao da fécula. O objetivo deste trabalho foi avaliar a produção de CDs usando fécula e farelo de mandioca como substratos, empregando ciclodextrina glucosiltransferase (CGTase; E. C. 2.4.1.19) proveniente de Bacillus macerans. A conversão do amido em a-CDs foi de 19% para a fécula e 21% para o farelo. Para b-CDs, os valores foram de 27% e 15% para a fécula e o farelo, respectivamente. A proporção de a: b-CDs produzidas a partir da fécula foi de 1,0:1,4, enquanto que para o farelo foi de 1,5:1,0. Após 4 horas a 50ºC houve considerável perda da atividade enzimática, indicando tendência de estabilização da reação.

Intersubband excitations at finite temperatures and their roles in different quasi-one-dimensional systems

We theoretically study many-body excitations in three different quasi-one-dimensional (Q1D) electron systems: (i) those formed on the surface of liquid Helium; (ii) in two coupled semiconductor quantum wires; and (iii) Q1D electrons embedded in polar semiconductor-based quantum wires. Our results show intersubband coupling between higher subbands and the two lowest subbands affecting even the lower energy intersubband plasmons on the liquid Helium surface. Concerning the second system, we show a pronounced extra peak appearing in the intersubband impurity spectral function for temperatures as high as 20 K. We finally show coupled intersubband plasmon-phonon modes surviving for temperatures up to 300 K.