1,209 research outputs found

    CD40 is constitutively expressed on platelets and provides a novel mechanism for platelet activation

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    CD40 is a 48-kDa phosphorylated transmembrane glycoprotein belonging to the TNF receptor superfamily. CD40 has been demonstrated on a range of cell types, and it has an important role in adaptive immunity and inflammation. CD40 has recently been described on platelets but platelet activation by CD40 has not been described. In the present study, we use flow cytometry and immunoblotting to confirm that platelets constitutively express surface CD40. CD40 mRNA was undetectable, suggesting that the protein is synthesized early in platelet differentiation by megakaryocytes. Ligation of platelet CD40 with recombinant soluble CD40L trimer (sCD40LT) caused increased platelet CD62P expression, -granule and dense granule release, and the classical morphological changes associated with platelet activation. CD40 ligation also caused ß3 integrin activation, although this was not accompanied by platelet aggregation. These actions were abrogated by the CD40L blocking antibody TRAP-1 and the CD40 blocking antibodies M2 and M3, showing that activation was mediated by CD40L binding to platelet CD40. ß3 integrin blockade with eptifibatide had no effect, indicating that outside-in signaling via IIbß3 was not contributing to these CD40-mediated effects. CD40 ligation led to enhanced platelet-leukocyte adhesion, which is important in the recruitment of leukocytes to sites of thrombosis or inflammation. Our results support a role for CD40-mediated platelet activation in thrombosis, inflammation, and atherosclerosis

    The micropolitics of behavioural interventions: a new materialist analysis

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    Behavioural approaches are increasingly used in both the global North and South as means to effect government policy. These interventions aim to encourage preferred behaviours by subtly shaping choices, applying incentives or employing punitive measures. Recent digital technology developments extend the reach of these behavioural approaches. While these approaches have been criticised from political science perspectives, in this paper we apply an innovative mode of analysis of behavioural policy approaches founded in a ‘new materialist’ ontology of affects, assemblages and capacities. This perspective enables us to explore their ‘micropolitical’ impact—on those who are their subjects, but also upon the wider sociocultural contexts within which they have been implemented. We examine two different behavioural interventions: the use of vouchers to incentivise new mothers to breastfeed their infants (a practice associated with improved health outcomes in both childhood and later life), and uses of debit card technologies in Australia to limit welfare recipients’ spending on alcohol, drugs and gambling. In each case, we employ a materialist methodology to analyse precisely what these interventions do, and what (in)capacities they produce in their targeted groups. From these we draw out a more generalised critique of behavioural approaches to policy implementation

    Ambiguity of gamma-ray tracking of "two-interaction" events

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    Tracking of gamma-ray interactions in germanium detectors can allow reconstruction of the photon paths, and is useful for many applications. Scrutiny of the kinematics and geometry of gamma rays which are Compton scattered only once prior to full absorption reveals that there are cases where even perfect spatial and energy resolution cannot resolve the true interaction sequence and consequently gamma-ray tracks cannot be reconstructed. The photon energy range where this ambiguity exists is from 255 keV to around 700 keV. This is a region of importance for nuclear structure research where two-point interactions are probable.Comment: 8 pages, 2 figure

    Spray growth of regular, synthetic, oxygenated and biodiesels in an optical engine

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    Spray formation has been studied in an optically accessible heavy-duty diesel engine for regular diesel,synthetic, oxygenated and biofuels using a high-speed digital camera. Images are analyzed with custom madealgorithms to obtain spray penetration length and spray cone angle as function of time. Results from 2 out of the 8 nozzle sprays have been used in the data analysis. Variation in spray equilibrium length and angle is observed between the fuels tested. Modelling of the fuel injection, taking great care to account for individual fuel properties, shows good correspondence with experimental results

    Spectral curves and the mass of hyperbolic monopoles

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    The moduli spaces of hyperbolic monopoles are naturally fibred by the monopole mass, and this leads to a nontrivial mass dependence of the holomorphic data (spectral curves, rational maps, holomorphic spheres) associated to hyperbolic multi-monopoles. In this paper, we obtain an explicit description of this dependence for general hyperbolic monopoles of magnetic charge two. In addition, we show how to compute the monopole mass of higher charge spectral curves with tetrahedral and octahedral symmetries. Spectral curves of euclidean monopoles are recovered from our results via an infinite-mass limit.Comment: 43 pages, LaTeX, 3 figure

    Laser beam attenuation in LIF measurements on NO in a diesel engine

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    The effect of laser beam attenuation on nitric oxide measurements in a diesel engine is presented. A number ofexperimental ways to correct for this attenuation are discussed: transmission measurements, bidirectional laserinducedfluorescence, and Raman scattering by N2. Comparison of the results indicates that the attenuation isgenerally not uniform over the cylinder. Instead it seems to be less severe over the field of view (i.e. the upper partof the cylinder)

    Laser beam attenuation in LIF measurements on NO in a diesel engine

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    The effect of laser beam attenuation on nitric oxide measurements in a diesel engine is presented. A number ofexperimental ways to correct for this attenuation are discussed: transmission measurements, bidirectional laserinducedfluorescence, and Raman scattering by N\u3csub\u3e2\u3c/sub\u3e. Comparison of the results indicates that the attenuation isgenerally not uniform over the cylinder. Instead it seems to be less severe over the field of view (i.e. the upper partof the cylinder)

    Quantitative nitric oxide measurements by means of laser-induced fluorescence in a heavy-duty Diesel engine

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    Quantitative in-cylinder laser-induced fluorescence measurements ofnitric oxide in a heavy-duty Diesel engine are presented. Special attention is paid to experimental techniques to assess the attenuation of the laser beam and the fluorescence signal by the cylinder contents.This attenuation can be considerable at certain stages in the combustionstroke. The temperature and pressure dependence of the fluorescence signal is described in various models. In this study, LIFsim was used.Finally, calibration was realized by concentration measurements in the exhaust gas

    The Entrepreneurial State: An Ownership Competence Perspective

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    Academics, pundits, and policymakers have recently called for a stronger governmental role in the economy to tackle social issues such as inequality and grand challenges like global warming. Despite a general recognition among economists and management scholars that government efforts to guide and control innovation or subsidize private entrepreneurs have failed to yield results, these calls also describe an entrepreneurial state in which bureaucrats, not entrepreneurs, direct not only basic research but also applied technological development. Building on the notions of economic competence and ownership competence we argue that even well-intentioned and strongly motivated public actors lack the ability to manage the process of innovation, especially under Knightian uncertainty. As stewards of resources owned by the public, government bureaucrats do not exercise the ultimate responsibility that comes with ownership. Moreover, government ownership of firms and labs and government intervention in the management of privately owned assets hampers the competitive process of putting ownership of innovative firms and projects in the hands of individuals and groups with higher levels of ownership ability. We suggest that ownership competence differs systematically between public and private actors, particularly around innovation, with important implications for innovation policy

    Barrier-free subsurface incorporation of 3d metal atoms into Bi(111) films

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    By combining scanning tunneling microscopy with density functional theory it is shown that the Bi(111) surface provides a well-defined incorporation site in the first bilayer that traps highly coordinating atoms such as transition metals (TMs) or noble metals. All deposited atoms assume exactly the same specific sevenfold coordinated subsurface interstitial site while the surface topography remains nearly unchanged. Notably, 3d TMs show a barrier-free incorporation. The observed surface modification by barrier-free subsorption helps to suppress aggregation in clusters. It allows a tuning of the electronic properties not only for the pure Bi(111) surface, but may also be observed for topological insulators formed by substrate-stabilized Bi bilayers. © 2015 American Physical Society.DFG/SFB/616DFG/SPP/1601DFG/Pf238/3
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