92,251 research outputs found

    Macrophage-derived upd3 Cytokine causes impaired glucose homeostasis and reduced lifespan in drosophila fed a lipid-rich diet

    Get PDF
    Long-term consumption of fatty foods is associated with obesity, macrophage activation and inflammation, metabolic imbalance, and a reduced lifespan. We took advantage of Drosophila genetics to investigate the role of macrophages and the pathway(s) that govern their response to dietary stress. Flies fed a lipid-rich diet presented with increased fat storage, systemic activation of JAK-STAT signaling, reduced insulin sensitivity, hyperglycemia, and a shorter lifespan. Drosophila macrophages produced the JAK-STAT-activating cytokine upd3, in a scavenger-receptor (crq) and JNK-dependent manner. Genetic depletion of macrophages or macrophage-specific silencing of upd3 decreased JAK-STAT activation and rescued insulin sensitivity and the lifespan of Drosophila, but did not decrease fat storage. NF-κB signaling made no contribution to the phenotype observed. These results identify an evolutionarily conserved “scavenger receptor-JNK-type 1 cytokine” cassette in macrophages, which controls glucose metabolism and reduces lifespan in Drosophila maintained on a lipid-rich diet via activation of the JAK-STAT pathway

    The Gentle Art of Retroduction: Critical Realism, Cultural Political Economy and Critical Grounded Theory

    Get PDF
    This article, first, proposes critical grounded theory (CGT) as a way to develop systematically an array of methods and theoretical propositions into a coherent critical methodology for organization studies (and beyond). Second, it demonstrates CGT’s usefulness through a case study of competing recovery projects from the Icelandic financial crisis. CGT is developed in engagement with the emerging paradigm of cultural political economy (CPE) and its preferred method of critical discourse analysis (CDA). CPE analyses the evolution of ‘economic imaginaries’ in both their structural/material and semiotic/discursive dimensions. This requires a critical realist, multi-dimensional research strategy which emphasizes ethnographic methods and substantial theoretical and historical work. The proposed methodology of CGT enables a retroductive research process that combines deductive theoretical deskwork with inductive fieldwork enabled by grounded theory tools to analyse organizational process, stability and change

    Chiral corrections to the SU(2)×SU(2)SU(2)\times SU(2) Gell-Mann-Oakes-Renner relation

    Get PDF
    The next to leading order chiral corrections to the SU(2)×SU(2)SU(2)\times SU(2) Gell-Mann-Oakes-Renner (GMOR) relation are obtained using the pseudoscalar correlator to five-loop order in perturbative QCD, together with new finite energy sum rules (FESR) incorporating polynomial, Legendre type, integration kernels. The purpose of these kernels is to suppress hadronic contributions in the region where they are least known. This reduces considerably the systematic uncertainties arising from the lack of direct experimental information on the hadronic resonance spectral function. Three different methods are used to compute the FESR contour integral in the complex energy (squared) s-plane, i.e. Fixed Order Perturbation Theory, Contour Improved Perturbation Theory, and a fixed renormalization scale scheme. We obtain for the corrections to the GMOR relation, δπ\delta_\pi, the value δπ=(6.2,±1.6)\delta_\pi = (6.2, \pm 1.6)%. This result is substantially more accurate than previous determinations based on QCD sum rules; it is also more reliable as it is basically free of systematic uncertainties. It implies a light quark condensate 2GeV=(267±5MeV)3 \simeq \equiv |_{2\,\mathrm{GeV}} = (- 267 \pm 5 MeV)^3. As a byproduct, the chiral perturbation theory (unphysical) low energy constant H2rH^r_2 is predicted to be H2r(νχ=Mρ)=(5.1±1.8)×103H^r_2 (\nu_\chi = M_\rho) = - (5.1 \pm 1.8)\times 10^{-3}, or H2r(νχ=Mη)=(5.7±2.0)×103H^r_2 (\nu_\chi = M_\eta) = - (5.7 \pm 2.0)\times 10^{-3}.Comment: A comment about the value of the strong coupling has been added at the end of Section 4. No change in results or conslusion

    Rapid and efficient stable gene transfer to mesenchymal stromal cells using a modified foamy virus vector

    Get PDF
    Mesenchymal stromal cells (MSCs) hold great promise for regenerative medicine. Stable ex vivo gene transfer to MSCs could improve the outcome and scope of MSC therapy, but current vectors require multiple rounds of transduction, involve genotoxic viral promoters and/or the addition of cytotoxic cationic polymers in order to achieve efficient transduction. We describe a self-inactivating foamy virus vector (FVV), incorporating the simian macaque foamy virus envelope and using physiological promoters, which efficiently transduces murine MSCs (mMSCs) in a single-round. High and sustained expression of the transgene, whether GFP or the lysosomal enzyme, arylsulphatase A (ARSA), was achieved. Defining MSC characteristics (surface marker expression and differentiation potential), as well as long-term engraftment and distribution in the murine brain following intracerebroventricular delivery, are unaffected by FVV transduction. Similarly, greater than 95% of human MSCs (hMSCs) were stably transduced using the same vector, facilitating human application. This work describes the best stable gene transfer vector available for mMSCs and hMSCs

    The power of the Monstrous: An introduction to the special issue

    Get PDF
    Alterity and Otherness have often been the privileged field of contemplation within Western philosophy. Since the Presocratic philosophers, Being has been defined in relation to – and more often opposed to – non-Being, just as Goodness has been considered in relation to Evil, Beauty in relation to the Ugly, Society in relation to Nature, and the examples could be multiplied ad libitum. Every identity is shaped in opposition to an excluded other, an outside, or some thing. Identity and alterity are thus constructed as two inseparable sides of a single, coherent philosophical discourse, or rather a field of various discourses that comprise a philosophy, associated with - although not limited to - the early centuries of what we call modernity

    The relationship between fragility, configurational entropy and the potential energy landscape of glass forming liquids

    Full text link
    Glass is a microscopically disordered, solid form of matter that results when a fluid is cooled or compressed in such a fashion that it does not crystallise. Almost all types of materials are capable of glass formation -- polymers, metal alloys, and molten salts, to name a few. Given such diversity, organising principles which systematise data concerning glass formation are invaluable. One such principle is the classification of glass formers according to their fragility\cite{fragility}. Fragility measures the rapidity with which a liquid's properties such as viscosity change as the glassy state is approached. Although the relationship between features of the energy landscape of a glass former, its configurational entropy and fragility have been analysed previously (e. g.,\cite{speedyfr}), an understanding of the origins of fragility in these features is far from being well established. Results for a model liquid, whose fragility depends on its bulk density, are presented in this letter. Analysis of the relationship between fragility and quantitative measures of the energy landscape (the complicated dependence of energy on configuration) reveal that the fragility depends on changes in the vibrational properties of individual energy basins, in addition to the total number of such basins present, and their spread in energy. A thermodynamic expression for fragility is derived, which is in quantitative agreement with {\it kinetic} fragilities obtained from the liquid's diffusivity.Comment: 8 pages, 3 figure

    Hydrodynamic simulations of shell convection in stellar cores

    Full text link
    Shell convection driven by nuclear burning in a stellar core is a common hydrodynamic event in the evolution of many types of stars. We encounter and simulate this convection (i) in the helium core of a low-mass red giant during core helium flash leading to a dredge-down of protons across an entropy barrier, (ii) in a carbon-oxygen core of an intermediate-mass star during core carbon flash, and (iii) in the oxygen and carbon burning shell above the silicon-sulfur rich core of a massive star prior to supernova explosion. Our results, which were obtained with the hydrodynamics code HERAKLES, suggest that both entropy gradients and entropy barriers are less important for stellar structure than commonly assumed. Our simulations further reveal a new dynamic mixing process operating below the base of shell convection zones.Comment: 8 pages, 3 figures .. submitted to a proceedings of conference about "Red Giants as Probes of the Structure and Evolution of the Milky Way" which has taken place between 15-17 November 2010 in Rom

    Serosurvey of antibody to highly pathogenic avian influenza (H5N1) in pigs, north central Nigeria

    Get PDF
    Avian influenza is a disease of economic and public health importance that has been described in most domestic animals and humans. Highly pathogenic avian influenza H5N1 epidemic in Nigeria was observed in agro-ecological zones where pigs and chickens are raised in shared environment with chances of interspecies transmission. We investigate the likelihood of transmission of the disease to pigs in North Central Nigeria where there were several cases of highly pathogenic avian influenza H5N1 in both commercial and free range poultry. Two hundred and twenty swine sera collected in Kaduna and Plateau states were screened for influenza A/H5N1 antibody by haemagglutination inhibition test according to standard protocol. All the sera tested were negative for influenza A/H5 antibody (HA titre < 22). Our inability to detect appreciable antibody level to avian influenza A/H5N1 therefore may be due to lack of infection because of low susceptibility of pigs to Influenza A/H5N1. We recommend wider serological and virological studies to identify other circulating influenza virus in pigs in different agro-ecological zones to provide useful epidemiological data on evolving influenza virus.&#160
    corecore