Browsing by Issue Date, starting with "2013-10"
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- Specificity in S-Nitrosylation: a short-range mechanism for NO signaling?Publication . Martinez-Ruiz, Antonio; Araújo, Inês; Izquierdo-Alvarez, Alicia; Hernansanz-Agustin, Pablo; Lamas, Santiago; Serrador, Juan M.Significance: Nitric oxide (NO) classical and less classical signaling mechanisms (through interaction with soluble guanylate cyclase and cytochrome c oxidase, respectively) operate through direct binding of NO to protein metal centers, and rely on diffusibility of the NO molecule. S-Nitrosylation, a covalent post-translational modification of protein cysteines, has emerged as a paradigm of nonclassical NO signaling. Recent Advances: Several nonenzymatic mechanisms for S-nitrosylation formation and destruction have been described. Enzymatic mechanisms for transnitrosylation and denitrosylation have been also studied as regulators of the modification of specific subsets of proteins. The advancement of modification-specific proteomic methodologies has allowed progress in the study of diverse S-nitrosoproteomes, raising clues and questions about the parameters for determining the protein specificity of the modification. Critical Issues: We propose that S-nitrosylation is mainly a short-range mechanism of NO signaling, exerted in a relatively limited range of action around the NO sources, and tightly related to the very controlled regulation of subcellular localization of nitric oxide synthases. We review the nonenzymatic and enzymatic mechanisms that support this concept, as well as physiological examples of mammalian systems that illustrate well the precise compartmentalization of S-nitrosylation. Future Directions: Individual and proteomic studies of protein S-nitrosylation-based signaling should take into account the subcellular localization in order to gain further insight into the functional role of this modification in (patho)physiological settings. Antioxid. Redox Signal. 19, 1220-1235.
- Exploring the consistency of the SF-6DPublication . Ferreira, Lara Noronha; Ferreira, Pedro L.; Pereira, Luis; Rowen, Donna; Brazier, John E.Objective: The six dimensional health state short form (SF-6D) was designed to be derived from the short-form 36 health survey (SF-36). The purpose of this research was to compare the SF-6D index values generated from the SF 36 (SF-6D(SF-36)) with those obtained from the SF-6D administered as an independent instrument (SF-6D(Ind)). The goal was to assess the consistency of respondents answers to these two methods of deriving the SF-6D. Methods: Data were obtained from a sample of the Portuguese population (n = 414). Agreement between the instruments was assessed on the basis of a descriptive system and their indexes. The analysis of the descriptive system was performed by using a global consistency index and an identically classified index. Agreement was also explored by using correlation coefficients. Parametric tests were used to identify differences between the indexes. Regression models were estimated to understand the relationship between them. Results: The SF-6D(Ind) generates higher values than does the SF-6D(SF-36), There were significant differences between the indexes across sociodemographic groups. There was a significant ceiling effect in the SF-6D(Ind) a but not in the SF-6D(SF-36). The correlation between the indexes was high but less than what was anticipated. The global consistency index identified the dimensions with larger differences. Considerable differences were found in two dimensions, possibly as a result of different item contexts. Further research is needed to fully understand the role of the different layouts and the length of the questionnaires in the respondents' answers. Conclusions: The results show that as the SF-6D was designed to derive utilities from the SF-36 it should be used in this way and not as an independent instrument.
- Reproduction and respiration of a climate change indicator species: effect of temperature and variable food in the copepod Centropages chierchiaePublication . Cruz, Joana; Garrido, Susana; Pimentel, Marta S.; Rosa, Rui; Santos, A. Miguel P.; Re, PedroThe abundance of the calanoid copepod Centropages chierchiae has increased at the northern limits of its distribution in recent decades, mainly due to oceanic climate forcing, suggesting this as a key species in monitoring climate change. Laboratory experiments were conducted to study the combined effect of temperature, food type and concentration on the egg production rate (EPR) and hatching success (HS) of C. chierchiae. Females were fed on two monoalgal diets (Gymnodinium sp. and Phaeodactylum tricornutum) at two food concentrations and at three different temperatures (13, 19, 24C). Respiration rates of both genders were measured at four different temperatures (8, 13, 19, 24C). EPR was significantly different between temperatures and food concentrations, the maximum EPR being attained when the copepods were exposed to high food levels and at 19C. Prey type significantly influenced EPR; feeding on P. tricornutum resulted in higher egg production than Gymnodinium sp. HS was significantly lower at 13C than at 19 and 24C and higher with Gymnodinium sp. Respiration rates were sex independent and increased exponentially with temperature. To maintain basal metabolism, the minimum food intake of P. tricornutum ranged between 0.4 and 1.8 g C and for Gymnodinium sp. between 0.03 and 0.13 g C. Food intake was always higher than the metabolic demands, except for the highest temperature tested (24C). The present results confirm the sensitivity of C. chierchiae to temperature variations and may help in understanding the successful expansion of its distribution towards northern latitudes.
- Artes e ciências em diálogoPublication . Carvalho, João Carlos Firmino Andrade deO Leitor, certamente, encontrará diversos motivos de interesse nesta obra polifónica. De facto, o presente livro, surgindo após a realização de um Colóquio Internacional na Universidade do Algarve, em janeiro de 2013, dedicado à temática das relações entre arte e ciência, reúne um considerável número de autores (Professores, Investigadores, Artistas, etc.), cujos textos versam sobre as múltiplas abordagens possíveis das relações entre as artes e as ciências, em distintos momentos e contextos históricos, colocando em diálogo áreas tão diversas como a matemática, a física, a biologia, a literatura, o cinema, o teatro, a pintura, a história da cultura, a história das ciências, a medicina, a arquitetura, a didática das ciências, a filosofia, etc. Claro que a natureza de tais diálogos é muito diferenciada, consoante o tipo de abordagem realizado por cada autor. O Leitor selecionará aquele(s) com que mais se identifique, de acordo com os seus interesses científicos, culturais, artísticos, profissionais. A distribuição dos textos na obra procurou, intencionalmente, sugerir a ideia de miscelânea de vários saberes, evitando-se a tradicional e cómoda arrumação por áreas de especialidade, por temas ou assuntos. A surpresa poderá incentivar o interesse e o espírito de descoberta do Leitor que, assim, poderá usufruir deste livro coletivo em tempos e espaços de leitura por si próprio decididos.
- Polar marine biology science in Portugal and Spain: Recent advances and future perspectivesPublication . Xavier, J.; Barbosa, Ana B.; Agustí, S.; Alonso-Sáez, L.; Alvito, P.; Ameneiro, J.; Ávila, C.; Baeta, A.; Canário, J.; Carmona, R.; Catry, P.; Ceia, F.; Clark, M. S.; Cristobo, F. J.; Cruz, B.; Duarte, C. M.; Figuerola, B.; Gili, J.-M.; Gonçalves, A. R.; Gordillo, F. J. L.; Granadeiro, J. P.; Guerreiro, M.; Isla, Enrique; Jiménez, C.; López-González, P. J.; Lourenço, S.; Marques, J. C.; Moreira, E.; Mota, A. M.; Nogueira, M.; Núñez-Pons, L.; Orejas, C.; Paiva, V. H.; Palanques, A.; Pearson, G. A.; Pedrós-Alió, C.; Peña Cantero, T. L.; Power, Deborah; Ramos, J. A.; Rossi, S.; Serrão, EsterPolar marine ecosystems have global ecological and economic importance because of their unique biodiversity and their major role in climate processes and commercial fisheries, among others. Portugal and Spain have been highly active in a wide range of disciplines in marine biology of the Antarctic and the Arctic. The main aim of this paper is to provide a synopsis of some of the results and initiatives undertaken by Portuguese and Spanish polar teams within the field of marine sciences, particularly on benthic and pelagic biodiversity (species diversity and abundance, including microbial, molecular, physiological and chemical mechanisms in polar organisms), conservation and ecology of top predators (particularly penguins, albatrosses and seals), and pollutants and evolution of marine organisms associated with major issues such as climate change, ocean acidification and UV radiation effects. Both countries have focused their polar research more in the Antarctic than in the Arctic. Portugal and Spain should encourage research groups to continue increasing their collaborations with other countries and develop multi-disciplinary research projects, as well as to maintain highly activememberships within major organizations, such as the Scientific Committee for Antarctic Research (SCAR), the International Arctic Science Council (IASC) and the Association of Polar Early Career Scientists (APECS), and in international research projects.
- Green synthesis of covellite nanocrystals using biologically generated sulfide: potential for bioremediation systemsPublication . Costa, J. P. da; Girão, Ana Violeta; Lourenço, J. P.; Monteiro, O. C.; Trindade, Tito; Costa, Maria ClaraThis work describes the synthesis of CuS powders in high yield and via an environmentally friendly and straightforward process, under ambient conditions (temperature and pressure), by adding to aqueous copper (II) a nutrient solution containing biologically generated sulfide from sulfate-reducing bacteria (SRB). The powders obtained were composed of CuS (covellite) nanoparticles (NPs) exhibiting a spheroid morphology (<5 nm). The relevance of this method to obtain CuS supported solid substrates has been demonstrated by performing the synthesis in the presence of TiO2 and SiO2 submicron particles. We further extended the work carried out, which substantiates the potential of using biogenic sulfide for the production of covellite nanocrystals and composites, using the effluent of a bioremediation column. Hence, such process results in the synthesis of added value products obtained from metal rich effluents, such as metallurgical and industrial ones, or Acid Mine Drainage (AMD), when associated with bioremediation processes.
- Ciência e arte (literária): vasos comunicantesPublication . Carvalho, João Carlos Firmino Andrade deApós algumas breves considerações iniciais acerca da natureza dialogal deste colóquio que permite levantar a questão das identidades e diferenças entre a arte e a ciência.
- Análise comparativa de medições de vibração e de isolamento sonoro em edifíciosPublication . Rosão, Vitor; Carreira, A. S.No presente trabalho foram efetuadas medições de isolamento sonoro in situ, de acordo com as normas aplicáveis da série ISO 140, e medições de vibração dos elementos separadores em causa. Pretende-se comparar os resultados das medições diretas de isolamento sonoro com os resultados das previsões de isolamento sonoro, tendo por base as medições de vibração, de forma a verificar a viabilidade de aplicação desta metodologia na determinação mais rigorosa dos caminhos de propagação sonora entre espaços e da definição mais rigorosa, eficaz e direcionada das intervenções de melhoria de isolamento sonoro a efetuar, quando necessárias.
- Utilização da realização de imagens animadas em função do ensino das ciências físicas e naturaisPublication . Graça, Marina Estela; Coelho, Ana CristinaEste artigo reporta uma primeira utilização da realização de um filme animado proposta a um conjunto de alunos, professores do ensino básico, como estratégia na aquisição de competências no contexto das atividades em ensino de ciências. As autoras conduziram os alunos numa experiência de conjugação de técnicas de produção de filmes animados com metodologias de delimitação e comunicação de conteúdos científicos, tendo em vista a sua implementação futura enquanto estratégia no ensino das ciências físicas e naturais no ensino básico. O artigo apresenta os objetivos e procedimentos desenvolvidos no processo, assim como a avaliação dos resultados obtidos após análise.
- Clear-water scour at pile groupsPublication . Lança, Rui; Fael, Cristina; Maia, Rodrigo; Pêgo, João; Cardoso, AntónioGroups of piles are frequently used as bridge foundations. Different group configurations, characterized by different pile spacing, skew-angle, number, and arrangement of pile group columns interact differently with the flow field and lead to different scour patterns and equilibrium scour depth. There have been a number of past studies on the characterization of scouring at pile groups, but most of them report short duration scour experiments. A priori, such short durations may be postulated to inherently carry important uncertainties into existing scour predictors. In this study, 75 long-duration laboratory tests were run under steady, clear-water flow close to the threshold for initiation of sediment motion, to address the effect of time, pile spacing, skew-angle and number of pile group columns on the equilibrium scour depth. Pile groups consisted of matrical arrangements of one, two, or three columns of four rows, with spacings of 1, 2, 3, 4.5, and 6 pile diameters; the tested skew-angles were 0, 15, 30, 45, and 90°. Important contributions were achieved on (1) the impact of the duration of tests on the shape of the scour hole as well as on the precision of coefficients involved in current predictors, (2) the most unfavorable skew angle, (3) the behavior of collapsed pile groups, (4) the maximum scour depth at pile groups composed of a single alignment, and (5) the performance of two current predictors of scour depth at pile groups. Two formulations of a predictor for the calculation of an aggregated pile group factor are suggested.