Protein oxidation by electrogenerated hydroxyl radicals

Many chronic diseases are associated to oxidative stress that can result from the unbalance between the production of reactive oxygen species and the action of antioxidant defense systems. Proteins are important targets as they are major components of cells. Modification of proteins structure, function and stability can result from the attack by different radicals, e.g. O2 - or HO. In order to characterize the damages caused by these radicals it is important to analyze the proteins oxidation products obtained from assays where radicals are generated by clean processes [1]. In this context the electrochemical generation of hydroxyl radicals can provide an alternative method, where these radicals are formed as intermediate in the oxidation of water to produce oxygen. Anodes of different materials, such as of boron doped diamond electrodes (BDD) and platinum (Pt), can be used for this purpose [3]. In this work it is considered the use of high reactive HO radicals (weakly adsorbed at BDD) and of low reactive HO radicals (strongly adsorbed at Pt) to oxidize BSA. The extension of BSA oxidation is analyzed for different experimental conditions, such as current density and electrolyte nature. BSA oxidation is monitored by means of carbonyl groups concentration and by the extension of protein cleavage

Concepção de experiências psicofísicas para visualização de imagens HDR em dispositivos móveis

Nos últimos catorze anos, foram muitas as técnicas desenvolvidas para redução da gama dinâmica de uma cena por forma a melhor mostrá-la em dispositivos de visualização comuns. Têm sido realizadas diversas experiências psicofísicas por forma a classificar num ranking os operadores de tone mapping (TMOs) mas, até à data, ninguém ousou testá-los em dispositivos com ecrãs pequenos como os PDAs (Personal Digital Assistants). O nosso objectivo consiste na escolha do(s) algoritmo(s) que melhor operam neste tipo de dispositivos. Esta decisão basear-se-á em resultados de experiências psicofísicas que serão realizadas. No entanto, é nossa preocupação conceber e conduzir tais experiências com o máximo cuidado e rigor. Assim, neste trabalho definimos as condições experimentais para avaliação dos TMOs em dispositivos com muito baixa gama dinâmica (VLDR – Very Low Dynamic Range)

Adolescents’ enjoyment in face-to-face physical education during the COVID-19 pandemic

The COVID-19 pandemic has had an impact on the routines of children and adolescents and on their level of involvement in physical activity (PA). The restrictive rules applied in this period affected the functioning of physical education (PE) classes in Portugal, and strongly limited student participation. The aim of this study was to analyze and compare the affective attitude (enjoyment) of adolescents during face-to-face PE lessons during the COVID-19 pandemic (from September 2020), according to sex, education, and PA levels. The study included 1369 students (621 boys and 748 girls), aged 12–18 years, Mage: 14.4; SD: 1.74. A validated online questionnaire was distributed between November and December 2020, and the data were analyzed for positive and negative affective attitude, using MANCOVAs (multivariate analysis of covariance) adjusted for sociodemographic and behavioral variables. The results showed higher negative affective attitudes in younger boys when compared to older boys and to girls in the same education level. Younger less active boys also showed higher negative affective attitudes than less active girls.info:eu-repo/semantics/publishedVersio