Caracterização do comportamento de ligações aço-betão

Os autores agradecem o apoio financeiro da Comissão Europeia através do Research Fund for Coal and Steel (RFCS) através do projecto de investigação Nº RFSR-CT-2007- 00051.No presente artigo abordam-se as ligações estruturais aço-betão utilizando uma configuração desenvolvida no projecto RFCS “InFaSo”. Efectua-se uma abordagem sequencial, com caracterização numérica e analítica de partes da ligação e da ligação completa. A validação experimental é feita sempre que possível com a contribuição dos resultados do referido projecto e da literatura disponível. Assim, propõem-se modelos numéricos e analíticos que permitem avaliar o comportamento de uma ligação entre viga mista e parede de betão armado.Research Fund for Coal and Steel (RFCS

Presence of extracellular DNA in the Candida albicans biofilm matrix and its contribution to biofilms

DNA has been described as a structural component of the extracellular matrix (ECM) in bacterial biofilms. In Candida albicans, there is a scarce knowledge concerning the contribution of extracellular DNA (eDNA) to biofilm matrix and overall structure. This work examined the presence and quantified the amount of eDNA in C. albicans biofilm ECM and the effect of DNase treatment and the addition of exogenous DNA on C. albicans biofilm development as indicators of a role for eDNA in biofilm development. We were able to detect the accumulation of eDNA in biofilm ECM extracted from C. albicans biofilms formed under conditions of flow, although the quantity of eDNA detected differed according to growth conditions, in particular with regards to the medium used to grow the biofilms. Experiments with C. albicans biofilms formed statically using a microtiter plate model indicated that the addition of exogenous DNA (>160 ng/ml) increases biofilm biomass and, conversely, DNase treatment (>0.03 mg/ml) decreases biofilm biomass at later time points of biofilm development. We present evidence for the role of eDNA in C. albicans biofilm structure and formation, consistent with eDNA being a key element of the ECM in mature C. albicans biofilms and playing a predominant role in biofilm structural integrity and maintenance.National Institute of Dental & Craniofacial ResearchFundação para a Ciência e Tecnologia (FCT) - SFRH/BD/28222/2006National Institute of Allergy and Infectious Disease

Rationale and design of EXPLORE: a randomized, prospective, multicenter trial investigating the impact of recanalization of a chronic total occlusion on left ventricular function in patients after primary percutaneous coronary intervention for acute ST-elevation myocardial infarction

<p>Abstract</p> <p>Background</p> <p>In the setting of primary percutaneous coronary intervention, patients with a chronic total occlusion in a non-infarct related artery were recently identified as a high-risk subgroup. It is unclear whether ST-elevation myocardial infarction patients with a chronic total occlusion in a non-infarct related artery should undergo additional percutaneous coronary intervention of the chronic total occlusion on top of optimal medical therapy shortly after primary percutaneous coronary intervention. Possible beneficial effects include reduction in adverse left ventricular remodeling and preservation of global left ventricular function and improved clinical outcome during future coronary events.</p> <p>Methods/Design</p> <p>The Evaluating Xience V and left ventricular function in Percutaneous coronary intervention on occLusiOns afteR ST-Elevation myocardial infarction (EXPLORE) trial is a randomized, prospective, multicenter, two-arm trial with blinded evaluation of endpoints. Three hundred patients after primary percutaneous coronary intervention for ST-elevation myocardial infarction with a chronic total occlusion in a non-infarct related artery are randomized to either elective percutaneous coronary intervention of the chronic total occlusion within seven days or standard medical treatment. When assigned to the invasive arm, an everolimus-eluting coronary stent is used. Primary endpoints are left ventricular ejection fraction and left ventricular end-diastolic volume assessed by cardiac Magnetic Resonance Imaging at four months. Clinical follow-up will continue until five years.</p> <p>Discussion</p> <p>The ongoing EXPLORE trial is the first randomized clinical trial powered to investigate whether recanalization of a chronic total occlusion in a non-infarct related artery after primary percutaneous coronary intervention for ST-elevation myocardial infarction results in a better preserved residual left ventricular ejection fraction, reduced end-diastolic volume and enhanced clinical outcome.</p> <p>Trial registration</p> <p>trialregister.nl NTR1108.</p

(I)Migrantes, diversidades e desigualdades no sistema educativo português : balanço e perspectivas

O objectivo do presente artigo consiste em procurar transmitir um olhar sociologicamente informado no que concerne à situação portuguesa no domínio das políticas educativas públicas e investigações produzidas relacionadas com o sistema educativo e a (i)migração, ou seja, com a tentativa de construção de uma educação intercultural. Neste sentido, será realizada uma análise descritiva e compreensivo-interpretativa da evolução desta problemática em Portugal desde que a mesma se tornou objecto de reflexão por parte de investigadores/as e políticos nos finais da década de oitenta, início da década de noventa do século XX. Nesta análise, será dada ênfase às investigações e quadros teóricos produzidos e às medidas legislativas e políticas educativas no domínio do tratamento da diferença cultural dentro do sistema educativo português.The aim of this article consists in attempting to transmit a sociologically informed view in what the Portuguese situation in the field of public policies and research related to the educational system and (im)migration are concerned, that is, in attempting to construct an intercultural education. In this way, a descriptive and comprehensiveinterpretative analysis of the evolution of this problem in Portugal will be realized, since the latter became an object of reflection on the part of researchers and politicians towards the end of the 80s, the beginning of the 90s of the XXth century. In this analysis, emphasis will be given on the research and theoretical frameworks produced and on the legislative measures and educational policies in the field of treating cultural difference in the Portuguese educational system

Aortic valve calcification volumes and chronic brain infarctions in patients undergoing transcatheter aortic valve implantation

Chronic silent brain infarctions, detected as new white matter hyperintensities on magnetic resonance imaging (MRI) following transcatheter aortic valve implantation (TAVI), are associated with long-term cognitive deterioration. This is the first study to investigate to which extent the calcification volume of the native aortic valve (AV) measured with cardiac computed tomography angiography (CTA) predicts the increase in chronic white matter hyperintensity volume after TAVI. A total of 36 patients (79 ± 5 years, median EuroSCORE II 1.9%, Q1–Q3 1.5–3.4%) with severe AV stenosis underwent fluid attenuation inversion recovery (FLAIR) MRI < 24 h prior to TAVI and at 3 months follow-up for assessment of cerebral white matter hyperintensity volume (mL). Calcification volumes (mm3) of the AV, aortic arch, landing zone and left ventricle were measured on the CTA pre-TAVI. The largest calcification volumes were found in the AV (median 692 mm3) and aortic arch (median 633 mm3), with a large variation between patients (Q1–Q3 482–1297 mm3 and 213–1727 mm3, respectively). The white matter hyperintensity volume increased in 72% of the patients. In these patients the median volume increase was of 1.1 mL (Q1–Q3 0.3–4.6 mL), corresponding with a 27% increase from baseline (Q1–Q3 7–104%). The calcification volume in the AV predicted the increase of white matter hyperintensity volume (Δ%), with a 35% increase of white matter hyperintensity volume, per 100 mm3 of AV calcification volume (SE 8.5, p < 0.001). The calcification volumes in the aortic arch, landing zone and left ventricle were not associated with the increase in white matter hyperintensity volume. In 72% of the patients new chronic white matter hyperintensities developed 3 months after TAVI, with a median increase of 27%. A higher calcification volume in the AV was associated with a larger increase in the white matter hyperintensity volume. These findings show the potential for automated AV calcium screening as an imaging biomarker to predict chronic silent brain infarctions