10 resultados para vascular access
em Universidade do Minho
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Dissertação de mestrado em Enfermagem
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One of the biggest concerns in the Tissue Engineering field is the correct vascularization of engineered constructs. Strategies involving the use of endothelial cells are promising but adequate cell sourcing and neo-vessels stability are enduring challenges. In this work, we propose the hypoxic pre-conditioning of the stromal vascular fraction (SVF) of human adipose tissue to obtain highly angiogenic cell sheets (CS). For that, SVF was isolated after enzymatic dissociation of adipose tissue and cultured until CS formation in normoxic (pO2=21%) and hypoxic (pO2=5%) conditions for 5 and 8 days, in basal medium. Immunocytochemistry against CD31 and CD146 revealed the presence of highly branched capillary-like structures, which were far more complex for hypoxia. ELISA quantification showed increased VEGF and TIMP-1 secretion in hypoxia for 8 days of culture. In a Matrigel assay, the formation of capillary-like structures by endothelial cells was more prominent when cultured in conditioned medium recovered from the cultures in hypoxia. The same conditioned medium increased the migration of adipose stromal cells in a scratch assay, when compared with the medium from normoxia. Histological analysis after implantation of 8 days normoxic- and hypoxic-conditioned SVF CS in a hindlimb ischemia murine model showed improved formation of neo-blood vessels. Furthermore, Laser Doppler results demonstrated that the blood perfusion of the injured limb after 30 days was enhanced for the hypoxic CS group. Overall, these results suggest that SVF CS created under hypoxia can be used as functional vascularization units for tissue engineering and regenerative medicine.
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Data traces, consisting of logs about the use of mobile and wireless networks, have been used to study the statistics of encounters between mobile nodes, in an attempt to predict the performance of opportunistic networks. Understanding the role and potential of mobile devices as relaying nodes in message dissemination and delivery depends on the knowledge about patterns and number of encounters among nodes. Data traces about the use of WiFi networks are widely available and can be used to extract large datasets of encounters between nodes. However, these logs only capture indirect encounters between nodes, and the resulting encounters datasets might not realistically represent the spatial and temporal behaviour of nodes. This paper addresses the impact of overlapping between the coverage areas of different Access Points of WiFi networks in extracting encounters datasets from the usage logs. Simulation and real-world experimental results show that indirect encounter traces extracted directly from these logs strongly underestimate the opportunities for direct node-to- node message exchange in opportunistic networks.
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Many funding agencies have Open Access mandates in place, but how often are scientific publications as outputs linked to funding details? The benefits of linking funding information to publications as part of the deposit workflow can assist in adhering to Open Access mandates. This paper examines how OpenAIRE – Open Access Infrastructure for Research in Europe – can ease monitoring Open Access and reporting processes for funders, and presents some results and opportunities. It also outlines how it relies on cleaned and curated repository content, a vital cog in the ever turning wheel of the global scholarly landscape, and the benefits it brings.
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Vascular grafts are used to bypass damaged or diseased blood vessels. Bacterial cellulose (BC) has been studied for use as an off-the-shelf graft. Herein, we present a novel, cost-effective, method for the production of small caliber BC grafts with minimal processing or requirements. The morphology of the graft wall produced a tensile strength above that of native vessels, performing similarly to the current commercial alternatives. As a result of the production method, the luminal surface of the graft presents similar topography to that of native vessels. We have also studied the in vivo behavior of these BC graft in order to further demonstrate their viability. In these preliminary studies, 1 month patency was achieved, with the presence of neo-vessels and endothelial cells on the luminal surface of the graft.
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Tese de Doutoramento em Medicina.
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BACKGROUND: By contrast with other southern European people, north Portuguese population registers an especially high prevalence of hypertension and stroke incidence. We designed a cohort study to identify individuals presenting accelerated and premature arterial aging in the Portuguese population. METHOD: Pulse wave velocity (PWV) was measured in randomly sampled population dwellers aged 18-96 years from northern Portugal, and used as a marker of early vascular aging (EVA). Of the 3038 individuals enrolled, 2542 completed the evaluation. RESULTS: Mean PWV value for the entire population was 8.4?m/s (men: 8.6?m/s; women: 8.2?m/s; P?0.02). The individuals were classified with EVA if their PWV was at least 97.5th percentile of z-score for mean PWV values adjusted for age (using normal European reference values as comparators). The overall prevalence of EVA was 12.5%; 26.1% of individuals below 30 years presented this feature and 40.2% of individuals in that same age strata were placed above the 90th percentile of PWV; and 18.7% of the population exhibited PWV values above 10?m/s, with male predominance (17.2% of men aged 40-49 years had PWV?>?10?m/s). Logistic regression models indicated gender differences concerning the risk of developing large artery damage, with women having the same odds of PWV above 10?m/s 10 years later than men. CONCLUSION: The population PWV values were higher than expected in a low cardiovascular risk area (Portugal). High prevalence rates of EVA and noteworthy large artery damage in young ages were found.
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The links between gender, sex and sexuality and their relevance are theoretically and politically problematic (Richardson, 2007). One of the difficulties in understanding their interconnections is that these terms are often used differently and ambiguously by different authors (and even by the same authors). This article reports the results of an analysis of the articles published in open access communication journals with known impact factor, edited in Portugal and published between 2005 and 2012. The diverse conceptualisations of those three basic concepts and of their (inter)relationships within communication research are identified. The complexity and the intricate (and often implicit) nature of both the meanings of these categories and their relationships underlie and justify our attention and further research. What the findings suggest about the current communication research into gender issues published in the two journals surveyed is that the ‘Gender differences discourse’ (Sunderland, 2004) is the most pervasive discourse (also) in academic practice. Additionally, they show that gender and sex are mainly taken for a fact, not a question that is worth being studied. The editors of these journals, as well as the scholars submitting manuscripts, need to be more aware of the traditional nature of the theoretical and methodological choices that they make regarding gender- and sex-related issues, as well as of the relative lack of attention to sexuality as a research subject.
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Public participation in environmental governance is typically associated with citizen access to power despite many closures and limitations having been identified in participatory processes. This article proposes an analytical framework to analyse discursive practices involved in public consultation processes. Critical Discourse Analysis is used to examine and appraise citizens’ access, standing and influence. We apply that framework to a ‘notice and comment’ process on a hydroelectric power plan in Portugal and show that it was discursively managed to justify the decision of constructing 10 large dams and to reject critical or alternative views. Citizens’ access, standing and influence were constrained through diverse discursive practices which (re)produced very unequal power relationsbetween policy proponents and participating individuals. More generally, the article illustrates the potential of Critical Discourse Analysis to assess voice(s) in policy processes. Focusing on argumentative, interactional and rhetorical levels, and how they are interwoven in public consultation discourses, the proposed framework is conceivably applicable in other studies.
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Transparency document related to this article can be found online at http://dx.doi.org/10.1016/j.bbrc.2015.10.014