50 research outputs found

    Surviving in isolation: genetic variation, bottlenecks and reproductive strategies in the Canarian endemic Limonium macrophyllum (Plumbaginaceae)

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    Oceanic archipelagos are typically rich in endemic taxa, because they offer ideal conditions for diversification and speciation in isolation. One of the most remarkable evolutionary radiations on the Canary Islands comprises the 16 species included in Limonium subsection Nobiles, all of which are subject to diverse threats, and legally protected. Since many of them are single-island endemics limited to one or a few populations, there exists a risk that a loss of genetic variation might limit their longterm survival. In this study, we used eight newly developed microsatellite markers to characterize the levels of genetic variation and inbreeding in L. macrophyllum, a species endemic to the North-east of Tenerife that belongs to Limonium subsection Nobiles. We detected generally low levels of genetic variation over all populations (HT = 0.363), and substantial differentiation among populations (FST = 0.188;RST = 0.186) coupled with a negligible degree of inbreeding (F = 0.042). Obligate outcrossing may have maintained L. macrophyllum relatively unaffected by inbreeding despite the species’ limited dispersal ability and the genetic bottlenecks likely caused by a prolonged history of grazing. Although several factors still constitute a risk for the conservation of L. macrophyllum, the lack of inbreeding and the recent positive demographic trends observed in the populations of this species are factors that favour its future persistence

    Examination of alkali-activated material nanostructure during thermal treatment

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    The key nanostructural changes occurring in a series of alkali-activated materials (AAM) based on blends of slag and fly ash precursors during exposure to temperatures up to 1000 °C are investigated. The main reaction product in each AAM is a crosslinked sodium- and aluminium-substituted calcium silicate hydrate (C-(N)-A-S-H)-type gel. Increased alkali content promotes the formation of an additional sodium aluminosilicate hydrate (N-A-S-(H)) gel reaction product due to the structural limitations on Al substitution within the C-(N)-A-S-H gel. Heating each AAM to 1000 °C results in the crystallisation of the disordered gels and formation of sodalite, nepheline and wollastonite. Increased formation of N-A-S-(H) reduces binder structural water content after thermal treatment and correlates closely with previous observations of improved strength retention and reduced microcracking in these AAM after heating to 1000 °C. This provides new insight into thermally induced changes to gel atomic structure and thermal durability of C-(N)-A-S-H/N-A-S-H gel blends which are fundamental for the development of new fire-resistant construction materials

    Using an equity-based framework for evaluating publicly funded health insurance programmes as an instrument of UHC in Chhattisgarh State, India

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    Universal health coverage (UHC) has provided the impetus for the introduction of publicly funded health insurance (PFHI) schemes in the mixed health systems of India and many other low- and middle-income countries. There is a need for a holistic understanding of the pathways of impact of PFHI schemes, including their role in promoting equity of access. Methods: This paper applies an equity-oriented evaluation framework to assess the impacts of PFHI schemes in Chhattisgarh State by synthesising literature from various sources and highlighting knowledge gaps. Data were collected from an extensive review of publications on PFHI schemes in Chhattisgarh since 2009, including empirical studies from the first author's PhD and grey literature such as programme evaluation reports, media articles and civil society campaign documents. The framework was constructed using concepts and frameworks from the health policy and systems research literature on UHC, access and health system building blocks, and is underpinned by the values of equity, human rights and the right to health

    Do Feeding and Eating Disorders Fit the General Definition of Mental Disorder?

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    AbstractThis paper aims at considering the conceptual status of feeding and eating disorders (FEDs). Now that the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) has changed the classification and some relevant criteria of FEDs, it is particularly relevant to evaluate their psychiatric framework and their status as mental disorders. I focus my efforts on addressing only one specific question: Do FEDs fit the DSM-5 general definition of mental disorder? In DSM-5 a mental disorder is defined as a syndrome that reflects a dysfunction and is usually associated with significant distress or disability. More importantly, there is an explicit statement saying that all mental disorders listed in the manual must meet the requirements highlighted by the general definition. Thus, I evaluate whether or not FEDs are really meant to reflect a dysfunction and are usually associated with significant distress or disability

    DNA/polyethylenimine transfection particles: Influence of ligands, polymer size, and PEGylation on internalization and gene expression

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    Receptor-binding ligands have been incorporated into DNA/polyethylenimine (PEI) complexes to enhance cell binding and cellular internalization. This study characterizes receptor-mediated uptake of DNA/PEI complexes on a cellular basis. A novel assay based on flow cytometry was applied, discriminating between total cell-associated and extracellularly bound DNA complexes. Receptor-mediated uptake of ligand-containing DNA/PEI (molecular weight, 800 kd) complexes was found to occur quickly (within 1 hour), whereas unspecific uptake through adsorptive endocytosis is less efficient or requires extended periods to reach the same degree of internalization. Rapid, receptor-mediated internalization requires a small complex size; however, large, aggregated complexes show higher gene expression. Using PEI 25 kd conjugated to large proteins such as transferrin or antibodies, improper condensation with DNA leads to suboptimal uptake and gene expression, whereas partial replacement of ligand-PEI with unconjugated PEI increases both uptake and transfection. In contrast, the 8 kd protein epidermal growth factor conjugated to PEI 25 kd properly condenses DNA and mediates specific uptake into human adenocarcinoma (KB) cells. Modification of the complex surface with appropriate amounts of poly(ethylene glycol) (PEG) does not block ligand-mediated internalization. A higher degree of PEGylation reduces the internalization of transferrin or antibody-containing complexes to a level similar to that of ligand-free complexes. In contrast, epidermal growth factor-mediated uptake is less effected by excessive PEGylation
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