3,426 research outputs found

    Highly bioactive silver and silver/titania composite films grown by chemical vapour deposition

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    This paper describes how photocatalytically active films of TiO2, grown by thermal CVD, may be functionally and structurally modified by deposition of nano-structured silver via a novel flame assisted CVD process. The resulting composite films are shown to be highly durable, highly photocatalytically active and are also shown to possess strong antibacterial behaviour. The deposition control, arising from the described approach, offers the potential to control the film nanostructure, which is proposed to be crucial in determining the photo and bio-activity of the combined film structure, and the transparency of the composite films. Furthermore, we show that the resultant films also exhibit “self-regeneration” capability, in that they both kill bacteria present on the film surface and then photo-degrade the residues. Such a dual action significantly reducing the problems of surface deactivation due to build up of contamination. These properties are especially significant when combined with the well-known durability of CVD deposited thin films, offering new opportunities for enhanced application in areas where bioactive surface functionality is sought

    Mathematical Modelling of Chemical Diffusion through Skin using Grid-based PSEs

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    A Problem Solving Environment (PSE) with connections to remote distributed Grid processes is developed. The Grid simulation is itself a parallel process and allows steering of individual or multiple runs of the core computation of chemical diffusion through the stratum corneum, the outer layer of the skin. The effectiveness of this Grid-based approach in improving the quality of the simulation is assessed

    A nuclear magnetic resonance study of water in aggrecan solutions

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    Aggrecan, a highly-charged macromolecule found in articular cartilage, was investigated in aqueous salt solutions with proton Nuclear Magnetic Resonance. The longitudinal and transverse relaxation rates were determined at two different field strengths, 9.4 T and 0.5 T, for a range of temperatures and aggrecan concentrations. The diffusion coefficients of the water molecules were also measured as a function of temperature and aggrecan concentration, using a pulsed field gradient technique at 9.4 T. Assuming an Arrhenius relationship, the activation energies for the various relaxation processes and the translational motion of the water molecules were determined from temperature dependencies as a function of aggrecan concentration in the range 0 – 5.3 % w/w. The longitudinal relaxation rate and inverse diffusion coefficient were approximately equally dependent on concentration and only increased by ≤ 20% from that of the salt solution. The transverse relaxation rate at high field demonstrated greatest concentration dependence, changing by an order of magnitude across the concentration range examined. We attribute this primarily to chemical exchange. Activation energies appeared to be approximately independent of aggrecan concentration, except for that of the low-field transverse relaxation rate, which decreased with concentration

    PWM4: THE RELATIONSHIP BETWEEN NOTTINGHAM HEALTH PROFILE DOMAINS AND CLINICAL CHARACTERISTICS OF WOMEN WITH ESTABLISHED POSTMENOPAUSAL OSTEOPOROSIS

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    Rank-based poverty measures and poverty ordering with an application to Tunisia

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    Using the normative approach, we develop a class of poverty measures that is function of a weighting system. Each particular weighting function corresponds to a particular social judgment. This offers the decision-maker a large selection of social preferences functions, and he can choose the one that best represents his social judgment. We also develop new concepts of a-extended TIP curves. They are used to establish the conditions of the robust and unanimous poverty ranking of our measures. These conditions are in terms of second-and higher-degree TIP dominance. Finally, we provide an empirical illustration using Tunisian data on the 2005–2010 period.info:eu-repo/semantics/publishedVersio

    Consenting to health record linkage: evidence from a multi-purpose longitudinal survey of a general population

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    Background: The British Household Panel Survey (BHPS) is the first long-running UK longitudinal survey with a non-medical focus and a sample covering the whole age range to have asked for permission to link to a range of administrative health records. This study determines whether informed consent led to selection bias and reflects on the value of the BHPS linked with health records for epidemiological research. Methods. Multivariate logistical regression is used, with whether the respondent gave consent to data linkage or not as the dependent variable. Independent variables were entered as four blocks; (i) a set of standard demographics likely to be found in most health registration data, (ii) a broader set of socio-economic characteristics, (iii) a set of indicators of health conditions and (iv) information about the use of health services. Results: Participants aged 16-24, males and those living in England were more likely to consent. Consent is not biased with respect to socio-economic characteristics or health. Recent users of GP services are underrepresented among consenters. Conclusions: Whilst data could only be linked for a minority of BHPS participants, the BHPS offers a great range of information on people's life histories, their attitudes and behaviours making it an invaluable source for epidemiological research. © 2012 Knies et al; licensee BioMed Central Ltd

    Maternal depressive symptoms and child social preference during the early school years: Mediation by maternal warmth and child emotion regulation

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    This longitudinal study examined processes that mediate the association between maternal depressive symptoms and peer social preference during the early school years. Three hundred and fifty six kindergarten children (182 boys) and their mothers participated in the study. During kindergarten, mothers reported their level of depressive symptomatology. In first grade, teachers rated children's emotion regulation at school and observers rated the affective quality of mother-child interactions. During second grade, children's social preference was assessed by peer nomination. Results indicated that mothers' level of depressive symptomatology negatively predicted their child's social preference 2 years later, controlling for the family SES and teacher-rated social preference during kindergarten. Among European American families, the association between maternal depressive symptoms and social preference was partially mediated by maternal warmth and the child's emotion regulation. Although the relation between maternal depressive symptoms and children peer preference was stronger among African American families than Europrean American families, its mediation by the maternal warmth and child's emotion regulation was not found in African American families. © 2010 The Author(s).published_or_final_versionSpringer Open Choice, 21 Feb 201

    Functional Analysis of the Chemokine Receptor CCR3 on Airway Epithelial Cells

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    The function of chemokine receptors on structural cells is only partially known. We previously reported the expression of a functional CCR3 receptor on airway epithelial cells (EC). We speculated that CCR3 might drive wound repair and expression of inflammatory genes in epithelium. The human airway EC lines BEAS-2B, 16-HBE, and primary bronchial EC were used to test the effect of in vitro challenge with the CCR3 ligands CCL11/eotaxin, CCL24/eotaxin-2, or CCL26/eotaxin-3 on 1) wound repair, using an established wound model; 2) cell proliferation and chemotaxis, using specific fluorometric assays; and 3) gene expression, using pathway-specific arrays for inflammatory and profibrotic cytokines, chemokines, and chemokine receptor genes. Agonist specificity was tested by cell pretreatment with an AstraZeneca CCR3 antagonist (10(-8) - 10(-6) M). CCL24 challenge significantly accelerated epithelial wound closure, with similar effects exerted by CCL11 and CCL26. This effect was time dependent, submaximal at 1 nM, and comparable in potency to epidermal growth factor. CCL24 induced a concentration-dependent increase in EC proliferation and chemotaxis, with significant effects observed at 10 nM. The AstraZeneca compound selectively inhibited these CCL24-mediated responses. CCL11 induced the up-regulation of several profibrogenic molecules such as fibroblast growth factor 1 and 5 and of several CC and CXC chemokines. Epithelial immunostaining for CCR3 was stronger in bronchial biopsies of asthmatics displaying marked inflammatory changes than in nondiseased samples. Epithelial CCR3 participates in key functions for wound repair, amplifies the expression of profibrogenic and chemokine transcripts, and appears up-regulated in inflamed asthmatic airways

    Functional diversity of marine ecosystems after the Late Permian mass extinction event

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    Article can be accessed from http://www.nature.com/ngeo/journal/v7/n3/full/ngeo2079.htmlThe Late Permian mass extinction event was the most severe such crisis of the past 500 million years and occurred during an episode of global warming. It is assumed to have had significant ecological impact, but its effects on marine ecosystem functioning are unknown and the patterns of marine recovery are debated. We analysed the fossil occurrences of all known Permian-Triassic benthic marine genera and assigned each to a functional group based on their inferred life habit. We show that despite the selective extinction of 62-74% of marine genera there was no significant loss of functional diversity at the global scale, and only one novel mode of life originated in the extinction aftermath. Early Triassic marine ecosystems were not as ecologically depauperate as widely assumed, which explains the absence of a Cambrian-style Triassic radiation in higher taxa. Functional diversity was, however, significantly reduced in particular regions and habitats, such as tropical reefs, and at these scales recovery varied spatially and temporally, probably driven by migration of surviving groups. Marine ecosystems did not return to their pre-extinction state, however, and radiation of previously subordinate groups such as motile, epifaunal grazers led to greater functional evenness by the Middle Triassic
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