2,500 research outputs found

    Functional differences between the susceptibility Z−2/C−106 and protective Z+2/T−106 promoter region polymorphisms of the aldose reductase gene may account for the association with diabetic microvascular complications

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    AbstractStudies have shown that polymorphisms located at positions −106 and approximately −2100 base pairs (5â€ČALR2) in the regulatory region of the aldose reductase gene are associated with susceptibility to microvascular complications in patients with diabetes. The aim was to investigate the functional roles of these susceptibility alleles using an in vitro gene reporter assay. Susceptibility, neutral and protective 5â€ČALR2/−106 alleles were transfected into HepG2 cells and exposed to excess d-glucose (d-glucose at final concentrations 14 or 28 mmol/l). Transcriptional activities were determined using a dual luciferase reporter gene assay. The “susceptibility alleles” Z−2 with C−106 had the highest transcriptional activity when compared with the “protective” combination of Z+2 with C−106 alleles (58.7±9.9 vs. 10.1±0.7; P<0.0001). Those constructs with either the Z or Z−2 in combination with the C−106 allele had significantly higher transcriptional activities when compared to those with the T−106 allele (Z/C−106, 37.4±5.4 vs. Z/T−106 7.7±1.6, P<0.003; Z−2/C−106, 58.7±9.9 vs. Z−2/T−106 10.9±0.6, P<0.0001). These results demonstrate that the Z−2/C−106 haplotype is associated with elevated transcriptional activity of the aldose reductase gene. This in turn may explain the role of these polymorphisms in the susceptibility to diabetic microvascular complications

    Using blubber explants to investigate adipose function in grey seals:glycolytic, lipolytic and gene expression responses to glucose and hydrocortisone

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    Adipose tissue is fundamental to energy balance, which underpins fitness and survival. Knowledge of adipose regulation in animals that undergo rapid fat deposition and mobilisation aids understanding of their energetic responses to rapid environmental change. Tissue explants can be used to investigate adipose regulation in wildlife species with large fat reserves, when opportunities for organismal experimental work are limited. We investigated glucose removal, lactate, glycerol and NEFA accumulation in media, and metabolic gene expression in blubber explants from wild grey seals. Glycolysis was higher in explants incubated in 25 mM glucose (HG) for 24 h compared to controls (C: 5.5 mM glucose). Adipose-derived lactate likely contributes to high endogenous glucose production in seals. Lipolysis was not stimulated by HG or high hydrocortisone (HC: 500 nM hydrocortisone) and was lower in heavier animals. HC caused NEFA accumulation in media to decrease by ~30% relative to C in females, indicative of increased lipogenesis. Lipolysis was higher in males than females in C and HG conditions. Lower relative abundance of 11-ÎČ-hydroxysteroid dehydrogenase 1 mRNA in HG explants suggests glucose involvement in blubber cortisol sensitivity. Our findings can help predict energy balance responses to stress and nutritional state in seals, and highlight the use of explants to study fat tissue function in wildlife

    Castells, 'Murdochization', Economic Counterpower and Livestreaming

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    In his Information Age trilogy, Manuel Castells documents the transformation of economic power by means of network affordances. In more recent work, he has built an account of the linking of economic power with cultural and political power through ‘Murdochization’ or ‘the networking of networks’. Whilst Castells’ account of power has thus developed to acknowledge the integration of economic, cultural and political interests within networks, his account of ‘counterpower’ remains largely focused on cultural and political resistance in the form of protest. Here we explore a case of economic counterpower, the unauthorized livestreaming of digital sports broadcasts. Analysis of this particular case (of counterpower) is particularly significant, given the centrality of Murdochization in Castells’ account of power in the network society. Emerging out of, alongside, and in response to the growth of, Murdochized digital media sports networks, we explore the scope and limits of livestreaming as a form of economic counterpower and counter-Murdochization. In this article, we document Castells’ theory of network power, the centrality of Murdochization to that account, and the centrality of monopoly control over digital sports broadcasting to Murdochized media empires. The scope and resilience of alternative streaming media in switching live sports programming from pay to view to free sharing is then examined. The failure to date of all attempts to prohibit free streams shows the ongoing viability of such economic counterpower. However, whilst dominant actors cannot eliminate economic counterpower, where dominant actors choose not to broadcast, no switching of content can take place

    Low Carbon Cities: Is Ambitious Action Affordable?

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    Research has begun to uncover the extent that greenhouse gas emissions can be attributed to cities, as well as the scope for cities to contribute to emissions reduction. But assessments of the economics of urban climate mitigation are lacking, and are currently based on selective case studies or specific sectors. Further analysis is crucial to enable action at the urban level. Here we consider the investment needs associated with 11 clusters of low carbon measures that could be deployed across the world’s urban areas in a way that is consistent with a broader 2°C target. Economic assessment of these low carbon measures finds that they could be deployed around the world with investments of c1trillionperyearbetween2015and2050(equivalentto1.31 trillion per year between 2015 and 2050 (equivalent to 1.3% of global GDP in 2014). When the direct savings that emerge from these measures due to avoided energy costs are considered, under the central scenario these investments have a net present value of c16.6 trillion USD in the period to 2050. However, discount rates, energy prices and rates of technological learning are key to the economic feasibility of climate action, with the NPV of these measures ranging from -1.1trillionUSDto1.1 trillion USD to 65.2 trillion USD under different conditions

    Metal accumulation kinetics by the estuarine macroalga, Fucusceranoides

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    The kinetics of Cu, Cd and Pb accumulation by the macroalga, Fucus ceranoides, was studied under simulated estuarine conditions. Accumulation of Cu and Pb proceeded via a pseudo-first-order reaction that was reversible, suggesting desorption or efflux of accumulated metal, with forward rate constants on the order of 0.1h-1. For both metals, reaction reversibility increased and the equilibrium constant decreased with increasing salinity (from 1 to 33.5) and system response times were <10h throughout. Accumulation of Cd proceeded via a first-order reaction that was irreversible, suggesting little desorption or efflux of metal, with rate constants that decreased with increasing salinity (from 0.023 to 0.015h-1) and reaction half-lives ranging from approximately 30-50h. Inorganic equilibrium speciation calculations suggest that interactions of Cu, Cd and Pb principally involve the respective free ions, but that additional ions (e.g. CdCl+) and biotic processes may also be significant. ‱Accumulation of Cu, Cd and Pb by the estuarine macroalga, Fucus ceranoides, decreases along a salinity gradient.‱Accumulation of Cu and Pb proceeds via a reversible pseudo-first-order reaction.‱In contrast, accumulation of Cd proceeds via an irreversible first-order reaction.‱Differences in reaction mechanisms are attributed to differences in the ability of metals to be internalised. © 2013 Elsevier Ltd

    Extra- and intra-cellular accumulation of platinum group elements by the marine microalga, Chlorella stigmatophora.

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    To better understand the marine biogeochemistry of the platinum group elements (PGE), Rh(III), Pd(II) and Pt(IV) were added in combination and at ppb concentrations to cultures of the marine microalga, Chlorella stigmatophora, maintained in sea water at 15 °C and under 60 Όmol m(-2) s(-1) PAR. The accumulation of PGE was established in short-term (24-h) exposures, and under varying conditions of algal biomass and PGE concentration, and in a longer-term exposure (156-h) by ICP-MS analysis of sea water and nitric acid digests and EDTA washes of the alga. In short-term exposures, and under all conditions, the extent of accumulation by C. stigmatophora was in the order: Rh > Pd >> Pt; and Pd was internalised (or resistant to EDTA extraction) to a considerably greater extent than Rh and Pt. Accumulation isotherms were quasi-linear up to added PGE concentrations of 30 Όg L(-1) and all metals displayed a significant reduction in accumulation on a weight-normalised basis with increasing density (biomass) of C. stigmatophora, an effect attributed to the production of exudates able to stabilise metals in sea water through complexation. In the longer-term exposure, kinetic constraints on the reactivities of Rh and, in particular, Pt, resulted in final degrees of accumulation and internalisation by C. stigmatophora that were greatest for Rh and similar between Pd and Pt. Among the PGE, therefore, Rh is predicted to participate in biological removal and transport processes in the marine environment to the greatest extent while decoupling in the biogeochemistries of Pd and Pt is predicted in shorter-term or more transient processes

    SO(n + 1) Symmetric Solutions of the Einstein Equations in Higher Dimensions

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    A method of solving the Einstein equations with a scalar field is presented. It is applied to find higher dimensional vacuum metrics invariant under the group SO(n + 1) acting on n-dimensional spheres.Comment: 11 page

    The Design and Development of Enhanced Thermal Desorption Products

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    This research study is based on a knowledge-transfer collaboration between The National Centre for Product Design and Development Research (PDR) and Markes International Ltd. The aim of the two-year collaboration has been to implement design tools and techniques for the development of enhanced thermal desorption products. Thermal desorption is a highly-specialised technique for the analysis of trace-level volatile organic compounds. This technique allows minute quantities of these compounds to be measured; however, there is an increasing demand from customers for greater sensitivity over a wider range of applications, which means new design methodologies need to be evaluated. The thermal desorption process combines a number of disparate chemical, thermal and mechanical disciplines, and the major design constraints arise from the need to cycle the sample through extremes in temperature. Following the implementation of a comprehensive product design specification, detailed design solutions have been developed using the latest 3D CAD techniques. The impact of the advanced design techniques is assessed in terms of improved product performance and reduced development times, and the wider implications of new product development within small companies are highlighted. 
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