Hydroxycinnamic acid antioxidants: an electrochemical overview

Hydroxycinnamic acids (such as ferulic, caffeic, sinapic, and p-coumaric acids) are a group of compounds highly abundant in food that may account for about one-third of the phenolic compounds in our diet. Hydroxycinnamic acids have gained an increasing interest in health because they are known to be potent antioxidants. These compounds have been described as chain-breaking antioxidants acting through radical scavenging activity, that is related to their hydrogen or electron donating capacity and to the ability to delocalize/stabilize the resulting phenoxyl radical within their structure.The free radical scavenger ability of antioxidants can be predicted from standard one-electron potentials. Thus, voltammetric methods have often been applied to characterize a diversity of natural and synthetic antioxidants essentially to get an insight into their mechanism and also as an important tool for the rational design of new and potent antioxidants.The structure-property-activity relationships (SPARs) correlations already established for this type of compounds suggest that redox potentials could be considered a good measure of antioxidant activity and an accurate guideline on the drug discovery and development process. Due to its magnitude in the antioxidant field, the electrochemistry of hydroxycinnamic acid-based antioxidants is reviewed highlighting the structure-property-activity relationships (SPARs) obtained so far.

Estudo comparativo de planeamentos dosimétricos em carcinoma de canal anal

O estudo pretende avaliar, sob o ponto de vista dosimétrico, a eficácia da técnica da estrela na redução da dose nos órgãos de risco face à técnica convencional, sem comprometer a dose tumoricida nos volumes alvo, em carcinoma de canal anal.

Os periódicos portugueses de emigração (1808-1822)

Esta dissertação analisa e compara os periódicos com uma componente de divulgação científica, editados por refugiados políticos em Londres e Paris, sendo o núcleo investigado composto por quatro títulos: o Correio Braziliense (1808-1822) e O Investigador Portuguez em Inglaterra (1811-1819), publicados em Londres, O Observador Lusitano em Pariz (1815) e os Annaes das Sciencias, das Artes, e das Letras (1818-1822), ambos com origem na capital francesa. Este estudo comporta uma discussão sobre questões historiográficas levantadas pelo estudo de periódicos de divulgação científica, nomeadamente num país com as particularidades de Portugal, a caracterização do período histórico em que decorreu a vida destas publicações, um panorama breve do estado das diversas ciências no plano internacional que nelas encontraram eco, seguidos da análise propriamente dita do núcleo de periódicos seleccionados. No âmbito desta última, deu-se particular destaque aos editores e ao seu percurso, ao lugar das ciências entre as matérias apresentadas por cada periódico, e aos temas e personalidades focadas. Foram identificadas as principais fontes citadas e analisou-se a participação dos leitores em cada periódico. Ressaltam como traços fundamentais destes periódicos o esforço desenvolvido pelos seus editores no sentido de sensibilizarem os governantes para a importância de alterarem práticas tradicionais e estruturas ultrapassadas, abrindo o país à informação proveniente do exterior e, em particular, ao desenvolvimento científico e económico.

Micro-generation Evaluation of the Zero Emissions Technologies in the Portuguese Market

Micro-generation is the small scale production of heat and/or electricity from a low carbon source and can be a powerful driver for carbon reduction, behavior change, security of supply and economic value. The energy conversion technologies can include photovoltaic panels, micro combined heat and power, micro wind, heat pumps, solar thermal systems, fuel cells and micro hydro schemes. In this paper, a small research of the availability of the conversion apparatus and the prices for the micro wind turbines and photovoltaic systems is made and a comparison between these two technologies is performed in terms of the availability of the resource and costs. An analysis of the new legal framework published in Portugal is done to realize if the incentives to individualspsila investment in sustainable and local energy production is worth for their point of view. An economic evaluation for these alternatives, accounting with the governmentpsilas incentives should lead, in most cases, into attractive return rates for the investment. Apart from the attractiveness of the investment there are though other aspects that should be taken into account and those are the benefits that these choices have to us all. The idea is that micro-generation will not only make a significant direct contribution to carbon reduction targets, it will also trigger a multiplier effect in behavior change by engaging hearts and minds, and providing more efficient use of energy by householders. The diversified profile of power generation by micro-generators, both in terms of location and timing, should reduce the impact of intermittency or plant failures with significant gains for security of supply.

Inspeção e manutenção de torres de radiocomunicações

Relatório de Estágio para obtenção de grau de Mestre em Engenharia Civil Área de Especialização de Edificações

Reabilitação de um imóvel industrial em Marvila: projeto de investimento

Trabalho de Projeto para obtenção do grau de Mestre em Engenharia Civil

Superoxide reductase from the syphilis spirochete Treponema pallidum

Superoxide reductase is a 14 kDa metalloprotein containing a catalytic nonhaem iron centre [Fe(His)4Cys]. It is involved in defence mechanisms against oxygen toxicity, scavenging superoxide radicals from the cell. The oxidized form of Treponema pallidum superoxide reductase was crystallized in the presence of polyethylene glycol and magnesium chloride. Two crystal forms were obtained depending on the oxidizing agents used after purification: crystals grown in the presence of K3Fe(CN)6 belonged to space group P21 (unit-cell parameters a = 60.3, b = 59.9, c = 64.8 A ° , = 106.9 ) and diffracted beyond 1.60 A ° resolution, while crystals grown in the presence of Na2IrCl6 belonged to space group C2 (a = 119.4, b = 60.1, c = 65.6 A ° , = 104.9 ) and diffracted beyond 1.55 A ° . A highly redundant X-ray diffraction data set from the C2 crystal form collected on a copper rotating-anode generator ( = 1.542 A ° ) clearly defined the positions of the four Fe atoms present in the asymmetric unit by SAD methods. A MAD experiment at the iron absorption edge confirmed the positions of the previously determined iron sites and provided better phases for model building and refinement. Molecular replacement using the P21 data set was successful using a preliminary trace as a search model. A similar arrangement of the four protein molecules could be observed.

Current mortars in conservation: an overview

Renders are an important item in historical buildings and the need for their periodical re-application is a basic conservation procedure. In modern times there has been a trend towards the replacement of traditional pure lime mortars by new formulations including Portland cement or hydraulic lime. Apart from those interventions on specific and very important monuments, in which the use oftraditional non-hydraulic mortars can be enforced, in most of the projects involving less than first order magnitude heritage the use of some sort of hydraulic components is becoming the rule rather than the exception. The present paper describes and analyses the results of an experimental study with ten formulations of current mortars - including some that can hardly be considered as adequate conservation procedures - allowing a direct comparison in terms of some of the most relevant characteristics.

Fóruns: comunicação on-line!

Este guião de apoio à formação, tem como objectivo apoiar docentes em (1)Utilizar fóruns para divulgação de informação e/ou colaboração de ideias e (2)Configurar e utilizar fóruns no moodle.

Exercício profissional, reconhecimento social e identidades: os espaços de construção da profissionalidade do ortoptista

Mestrado em Intervenção Sócio-Organizacional na Saúde - Área de especialização: Diagnóstico e Intervenção Organizacional e Comunitária

Aspectos geotécnicos na construção de túneis em áreas urbanas: Aplicação a terrenos de baixa resistência do miocénico de Lisboa

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Geológica (Geotecnia)

Análise cromatográfica e identificação de marcadores de envelhecimento de documentos gráficos

Dissertação apresentada para obtenção do grau de Mestre em Bioorgânica

Machine learning Vasicek model calibration with Gaussian processes

In this article, we calibrate the Vasicek interest rate model under the risk neutral measure by learning the model parameters using Gaussian processes for machine learning regression. The calibration is done by maximizing the likelihood of zero coupon bond log prices, using mean and covariance functions computed analytically, as well as likelihood derivatives with respect to the parameters. The maximization method used is the conjugate gradients. The only prices needed for calibration are zero coupon bond prices and the parameters are directly obtained in the arbitrage free risk neutral measure.

Distribuição de Alcatraz (Morus bassanus) na costa continental portuguesa e sua relação com variáveis ambientais

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do Grau de Mestre em Ecologia, Gestão e Modelação dos Recursos Marinhos

Pt/Carbon materials as Bi-Functional catalysts for N-decane hydroisomerization

The activity and selectivity of bi-functional carbon-supported platinum catalysts for the hydroisomerization of n-alkanes have been studied. The influence of the properties of the carbon support on the performance of the catalysts were investigated by incorporating the metallic function on a series of carbons with varied porosity (microporous: GL-50 from Norit, and mesoporous: CMK-3) and surface chemistry (modified by wet oxidation). The characterization results achieved with H-2 chemisorption and TEM showed differences in surface metal concentrations and metal-support interactions depending on the support composition. The highest metal dispersion was achieved after oxidation of the carbon matrix in concentrated nitric acid, suggesting that the presence of surface functional sites distributed in inner and outer surface favors a homogeneous metal distribution. On the other hand, the higher hydrogenating activity of the catalysts prepared with the mesoporous carbon pointed out that a fast molecular traffic inside the pores plays an important role in the catalysts performance. For n-decane hydroisomerization of long chain n-alkanes, higher activities were obtained for the catalysts with an optimized acidity and metal dispersion along with adequate porosity, pointing out the importance of the support properties in the performance of the catalysts.