Materials Design - Towards a Functionally Graded Electrical Conductor

In this study, we discuss functionally graded (FG) materials as pulsed electrical conductors. These conductors can be designed to be more efficient and longer lasting by applying numerical modeling tools. One focus is on limiting the thermal fatigue damage in conductors caused by very high temperatures that develop during pulse heating. We have quantified the effect of various grading functions on the pulsed Joule heating generated and the peak temperature experienced in the conductors of an electromagnetic launcher by using a 1D numerical code and a state of the art 3D coupled finite element code, EMAP3D. Because FG materials incorporate applications-tailored compositions, structures, and dimensions, smoothly graded properties in lateral and longitudinal cross sections are obtainable. The Solid Freeform Fabrication (SFF) processing approach allows for architectures with a series of important features. These features include the selective use of high efficiency conducting materials in the core, preconditioned conductor/structure interfaces, and built-in features for enhanced cooling where necessary.Mechanical Engineerin

Nanotechnology and the Developing World

How nanotechnology can be harnessed to address some of the world's most critical development problem

Effects of Melanin-Induced Free Radicals on the Isolated Rat Peritoneal Mast Cells

Pheomelanin from human red hair (RHM) produces considerably more cellular damage in Ehrlich ascites carcinoma cells when subjected to radiations of wavelength 320-700nm than eumelanin from black hair (BHM). Irradiation of RHM generated large amounts of superoxide while BHM did not produce detectable amounts of superoxide. The present investigations describe the effects of irradiation of mast cells in the presence of various natural and synthetic melanins. Irradiation of mast cells in the presence of RHM and red hair melanoprotein released large amounts of histamine while BHM and synthetic melanins prepared from dopa, cysteinyldopa, or a mixture of dopa and cysteinyldopa did not release histamine. The release of histamine at lower concentrations of RHM was not accompanied by the release of 51Cr from chromium-loaded cells, suggesting that this release was of noncytotoxic nature. On the other hand, the release of histamine at higher concentrations of RHM was due to cell lysis since both histamine and cytoplasmic marker 51Cr were released to the same extent. The release evoked by large concentration RHM was not inhibited by superoxide dismutase or catalase. This suggests that the cell lysis under these conditions was not due to H2O2 or O2-. The finding that mast cells release histamine when irradiated in the presence of RHM suggests that the immediate and late-phase reactions seen in sunburn may in part be due to the release of mediators from these cells

Roles of Education and IQ in Cognitive Reserve in Parkinson's Disease-Mild Cognitive Impairment.

Background/aimsThe role of cognitive reserve in Parkinson's disease (PD)-mild cognitive impairment (MCI) is incompletely understood.MethodsThe relationships between PD-MCI, years of education, and estimated premorbid IQ were examined in 119 consecutive non-demented PD patients using logistic regression models.ResultsHigher education and IQ were associated with reduced odds of PD-MCI in univariate analysis. In multivariable analysis, a higher IQ was associated with a significantly decreased odds of PD-MCI, but education was not.ConclusionThe association of higher IQ and decreased odds of PD-MCI supports a role for cognitive reserve in PD, but further studies are needed to clarify the interaction of IQ and education and the impact of other contributors such as employment and hobbies

A CD4+ T cell antagonist epitope down-regulates activating signaling proteins, up-regulates inhibitory signaling proteins and abrogates HIV-specific T cell function

BACKGROUND: CD4(+) T cells are critically important in HIV infection, being both the primary cells infected by HIV and likely playing a direct or indirect role in helping control virus replication. Key areas of interest in HIV vaccine research are mechanisms of viral escape from the immune response. Interestingly, in HIV infection it has been shown that peptide sequence variation can reduce CD4(+) T cell responses to the virus, and small changes to peptide sequences can transform agonist peptides into antagonist peptides. RESULTS: We describe, at a molecular level, the consequences of antagonism of HIV p24-specific CD4(+) T cells. Antagonist peptide exposure in the presence of agonist peptide caused a global suppression of agonist-induced gene expression and signaling molecule phosphorylation. In addition to down-regulation of factors associated with T cell activation, a smaller subset of genes associated with negative regulation of cell activation was up-regulated, including KFL-2, SOCS-1, and SPDEY9P. Finally, antagonist peptide in the absence of agonist peptide also delivered a negative signal to T cells. CONCLUSIONS: Small changes in p24-specific peptides can result in T cell antagonism and reductions of both T cell receptor signaling and activation. These changes are at least in part mediated by a dominant negative signal delivered by antagonist peptide, as evidenced by up-regulation of negative regulatory genes in the presence of agonist plus antagonist stimulation. Antagonism can have dramatic effects on CD4(+) T cell function and presents a potential obstacle to HIV vaccine development

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

Social and ethical criteria for prioritizing patients: a survey of students and health professionals in Portugal

O estudo quali-quantitativo explora o dilema ético da microalocação dos recursos da saúde. Objetiva identificar e comparar a opinião de dois grupos da sociedade portuguesa - estudantes e profissionais de saúde sobre a importância das características pessoais dos pacientes no momento de os priorizar e se as escolhas se explicam por referenciais bioéticos de caráter utilitaristas ou deontológicos. Os dados foram recolhidos através de um questionário aplicado a uma amostra de 180 estudantes universitários e 60 profissionais de saúde. Os respondentes perante hipotéticos cená- rios de emergência clínica tiveram de escolher de entre dois pacientes (distinguidos por idade, sexo, responsabilidade social, situação económica e laboral, comportamentos lesivos da saúde e registo criminal) quem tratar e justificar a escolha. Foram usados testes estatísticos de associação para comparar as respostas dos dois grupos e análise de conteúdo para categorizar as justificações. Os resultados sugerem a existência de diferenças nas escolhas dos dois grupos, com os profissionais de saúde a revelarem aceitar menos a utilização de critérios sociais em contexto de escassez e coexistência de critérios utilitaristas e deontológicos, com predomínio da eficiência por parte dos profissionais de saúde e da equidade por parte dos estudantesThis qualitative/quantitative study examines the ethical dilemma of microallocation of health resources. It seeks to identify and compare the opinion of two groups in Portuguese society – students and health professionals – on the importance of personal characteristics of patients at the moment of prioritizing them and if the choices can be explained by bioethical references of a utilitarian or deontological nature. Data were collected by means of a questionnaire administered to a sample of 180 students and 60 health professionals. Faced with hypothetical emergency scenarios, the respondents had to choose between two patients (distinguished by: age, gender, social responsibility, economic and employment situation, harmful health behaviors and criminal record), duly selecting who to treat and then justifying their choice. The results suggest the existence of differences in choices between the two groups, with health professionals revealing they are less prepared to accept the use of social criteria in a context of scarce resources and co-existence of utilitarian and deontological criteria, with a predominance of efficiency on the part of health professionals and equity on the part of students.info:eu-repo/semantics/publishedVersio

The extracellular matrix and insulin resistance

The extracellular matrix (ECM) is a highly dynamic compartment that undergoes remodeling as a result of injury and repair. Over the past decade, mounting evidence in humans and rodents suggest that ECM remodeling is associated with diet-induced insulin resistance in several metabolic tissues. Additionally, integrin receptors for the ECM have also been implicated in the regulation of insulin action. This review will address what is currently known about the ECM, integrins and insulin action in the muscle, liver and adipose tissue. Understanding how ECM remodeling and integrin signaling regulates insulin action may aid in the development of new therapeutic targets for the treatment of insulin resistance and type 2 diabetes