490 resultados para 1494


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The intense AC magnetic field required to produce levitation in terrestrial conditions, along with the buoyancy and thermo-capillary forces, results in turbulent convective flow within the droplet. The use of a homogenous DC magnetic field allows the convective flow to be damped. However the turbulence properties are affected at the same time, leading to a possibility that the effective turbulent damping is considerably reduced. The MHD modified K-Omega turbulence model allows the investigation of the effect of magnetic field on the turbulence. The model incorporates free surface deformation, the temperature dependent surface tension, turbulent momentum transport, electromagnetic and gravity forces. The model is adapted to incorporate a periodic laser heating at the top of the droplet, which have been used to measure the thermal conductivity of the material by calculating the phase lag between the frequency of the laser heating and the temperature response at the bottom. The numerical simulations show that with the gradual increase of the DC field the fluid flow within the droplet is initially increasing in intensity. Only after a certain threshold magnitude of the field the flow intensity starts to decrease. In order to achieve the flow conditions close to the ‘laminar’ a D.C. magnetic field >4 Tesla is required to measure the thermal conductivity accurately. The reduction in the AC field driven flow in the main body of the drop leads to a noticeable thermo-capillary convection at the edge of the droplet. The uniform vertical DC magnetic field does not stop a translational oscillation of the droplet along the field, which is caused by the variation in total levitation force due to the time-dependent surface deformation.

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Knipholone (KP) and knipholone anthrone (KA) are natural 4-phenylanthraquinone structural analogues with established differential biological activities including in vitro antioxidant and cytotoxic properties. By using DNA damage as an experimental model, the comparative Cu(II)-dependent prooxidant action of these two compounds were studied. In the presence of Cu(II) ions, the antioxidant KA (3.1-200 [mu]M) but not KP (6-384 [mu]M) caused a concentration-dependent pBR322 plasmid DNA strand scission. The DNA damage induced by KA could be abolished by reactive oxygen species scavengers, glutathione and catalase as well as EDTA and a specific Cu(I) chelator bathocuproine disulfonic acid. In addition to Cu(II) chelating activity, KA readily reduces Cu(II) to Cu(I). Copper-dependent generation of reactive oxygen species and the subsequent macromolecular damage may be involved in the antimicrobial and cytotoxic activity of KA.

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Background: Ischaemic heart disease (IHD) is a complex disease due to the combination of environmental and genetic factors. Mutations in the MEF2A gene have recently been reported in patients with IHD. In particular, a 21 base pair deletion (Δ7aa) in the MEF2A gene was identified in a family with an autosomal dominant pattern of inheritance of IHD. We investigated this region of the MEF2A gene using an Irish family-based study, where affected individuals had early-onset IHD. Methods: A total of 1494 individuals from 580 families were included (800 discordant sib-pairs and 64 parent-child trios). The Δ7aa region of the MEF2A gene was investigated based on amplicon size. Results: The Δ7aa mutation was not detected in any individual. Variation in the number of CAG (glutamate) and CCG (proline) residues was detected in a nearby region. However, this was not found to be associated with IHD. Conclusion: The Δ7aa mutation was not detected in any individual within the study population and is unlikely to play a significant role in the development of IHD in Ireland. Using family-based tests of association the number of tri-nucleotide repeats in a nearby region of the MEF2A gene was not associated with IHD in our study group. © 2006 Horan et al; licensee BioMed Central Ltd.

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Background: The complement factor H (CFH) gene has been recently confirmed to play an essential role in the development of age-related macular degeneration (AMD). There are conflicting reports of its role in coronary heart disease. This study was designed to investigate if, using a family-based approach, there was an association between genetic variants of the CFH gene and risk of early-onset coronary heart disease. Methods: We evaluated 6 SNPs and 5 common haplotypes in the CFH gene amongst 1494 individuals in 580 Irish families with at least one member prematurely affected with coronary heart disease. Genotypes were determined by multiplex SNaPshot technology. Results: Using the TDT/S-TDT test, we did not find an association between any of the individual SNPs or any of the 5 haplotypes and early-onset coronary heart disease. Conclusion: In this family-based study, we found no association between the CFH gene and early-onset coronary heart disease. © 2007 Meng et al; licensee BioMed Central Ltd.

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Coronary heart disease (CHD) remains a leading cause of death across the world. A region on chromosome 9p21.3 has been recently reported to be associated with CHD. We evaluated 3 SNPs and 3 common haplotypes in the 9p21.3 region in 1494 individuals from 580 Irish families, where at least 1 member had early-onset (males

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Following surgery for esophageal cancer, patients can experience complex physical, social, and emotional changes. Investigation of these challenges, particularly from the perspective of the patient and his or her carer, has been limited. The current study explored the emotional and cognitive experiences of esophageal cancer survivors and those of their carers, using focus groups conducted with members of a patient support group. Analysis of the patients’ data yielded three themes: coping with a death sentence, adjusting to and accepting an altered self, and the unique benefits of peer support. Analysis of the carers’ data also yielded three themes: the carer as buffer, representations of recovery and recurrence, and normalizing experiences through peer support. Esophageal cancer patients and their carers require holistic support in their efforts to adjust to the social, emotional, and physical consequences of esophagectomy. Peers could be an effective channel for the support of patients and carers.

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Abstract This work addresses the problems of effective in situ measurement of the initiation or the rate of steel corrosion in reinforced concrete structures through the use of optical fiber sensor systems. By undertaking a series of tests over prolonged periods, coupled with acceleration of corrosion, the performance of fiber Bragg grating-based sensor systems attached to high-tensile steel reinforcement bars (ldquorebarsrdquo), and cast into concrete blocks was determined, and the results compared with those from conventional strain gauges where appropriate. The results show the benefits in the use of optical fiber networks under these circumstances and their ability to deliver data when conventional sensors failed.

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Studies of individual nutrients or foods have revealed much about dietary influences on bone. Multiple food or nutrient approaches, such as dietary pattern analysis, could offer further insight but research is limited and largely confined to older adults. We examined the relationship between dietary patterns, obtained by a posteriori and a priori methods, and bone mineral status (BMS; collective term for bone mineral content (BMC) and bone mineral density (BMD)) in young adults (20-25 years; n 489). Diet was assessed by 7 d diet history and BMD and BMC were determined at the lumbar spine and femoral neck (FN). A posteriori dietary patterns were derived using principal component analysis (PCA) and three a priori dietary quality scores were applied (dietary diversity score (DDS), nutritional risk score and Mediterranean diet score). For the PCA-derived dietary patterns, women in the top compared to the bottom fifth of the 'Nuts and Meat' pattern had greater FN BMD by 0.074 g/cm(2) (P=0.049) and FN BMC by 0.40 g (P=0.034) after adjustment for confounders. Similarly, men in the top compared to the bottom fifth of the 'Refined' pattern had lower FN BMC by 0.41 g (P-0.049). For the a priori DDS, women in the top compared to the bottom third had lower FN BMD by 0.05 g/cm(2) after adjustments (P=0.052), but no other relationships with BMS were identified. In conclusion, adherence to a 'Nuts and Meat' dietary pattern may be associated with greater BMS in young women and a 'Refined' dietary pattern may be detrimental for bone health in young men.

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Multiple-cue probability learning (MCPL) involves learning to predict a criterion when outcome feedback is provided for multiple cues. A great deal of research suggests that working memory capacity (WMC) is involved in a wide range of tasks that draw on higher level cognitive processes. In three experiments, we examined the role of WMC in MCPL by introducing measures of working memory capacity, as well as other task manipulations. While individual differences in WMC positively predicted performance in some kinds of multiple-cue tasks, performance on other tasks was entirely unrelated to these differences. Performance on tasks that contained negative cues was correlated with working memory capacity, as well as measures of explicit knowledge obtained in the learning process. When the relevant cues predicted positively, however, WMC became irrelevant. The results are discussed in terms of controlled and automatic processes in learning and judgement. © 2011 The Experimental Psychology Society.

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Background: Although research has shown that significant burden and adverse psychological impact are associated with caring for a child with brain injury, limited knowledge exists concerning the qualitative experience and impact of this burden.
Objective: To provide an account of the experiences of mothers who care for a childhood survivor of brain injury.
Research design: Postal survey.
Methods and procedures: A self-report questionnaire was sent to a consecutive sample of mothers (n=86) of children (aged 8-28) with acquired brain injury, registered with a UK children’s brain injury charity. Five essay style questions enabled mothers to reflect on and describe at length their caring experiences, with particular emphasis placed on the perceived impact on emotional well-being.
Main outcomes and results: Thematic analysis identified five key themes: Perpetually Anxious, The Guilty Carer, The Labour of Caring, A Self-Conscious Apologist and Perpetually Grieving. Collectively, these themes highlight two core processes shaping mothers’ caring experiences and concomitant mental well-being. Firstly, the collective and enduring nature of caregiver burden over time. Second, the crucial role played by socio-cultural values in perpetuating caregiver burden.
Conclusions: Societal norms, particularly those relating to the nature and outcome of brain injury and motherhood, serve to marginalise mothers and increase feelings of isolation. Findings suggest the value of peer support programs as an effective means of providing appropriate social support.

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Dissertação apresentada para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Arqueologia

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À partir d'entretiens et d'observations réalisés dans une pharmacie de garde de Suisse romande, cette étude explore les relations que les pharmaciens d'officine entretiennent avec les usagers. Dans un contexte de démocratisation des savoirs relatifs à la santé, l'enquête effectuée montre que cette relation se reconfigure, selon la nature du problème de santé, au profit d'une plus grande autonomie des usagers. En effet, dans certaines situations, les usagers peuvent exprimer le désir de se passer de la compétence du pharmacien. Mais, dans d'autres circonstances, bien que s'efforçant de s'adapter aux demandes des usagers, les professionnels peuvent réaffirmer leur autorité d'expert si le problème soulevé ou les médicaments désirés nécessitent plus de vigilance. La relation pharmacien-usager oscille donc dans une négociation constante selon la marge de manoeuvre dont, dans une situation donnée, les uns et les autres disposent.