1,084 research outputs found

    Governing the Infections Bacteria Commons: Preventing Antibiotic Resistance

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    In recent decades, concerns have arisen over the misuse of antibiotics and the resultant increase in ever-more resilient strains of pathogenic bacteria. The author examines this issue through the lens of common pool resource theory, which frames a case study comparison between the United States and the Netherlands and their respective antibiotic distribution practices. The results of the case study offer insights into how the United States can better manage its antibiotic and public health policies

    Holographic Coulomb Branch Flows with N=1 Supersymmetry

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    We obtain a large, new class of N=1 supersymmetric holographic flow backgrounds with U(1)^3 symmetry. These solutions correspond to flows toward the Coulomb branch of the non-trivial N=1 supersymmetric fixed point. The massless (complex) chiral fields are allowed to develop vevs that are independent of their two phase angles, and this corresponds to allowing the brane to spread with arbitrary, U(1)^2 invariant, radial distributions in each of these directions. Our solutions are "almost Calabi-Yau:" The metric is hermitian with respect to an integrable complex structure, but is not Kahler. The "modulus squared" of the holomorphic (3,0)-form is the volume form, and the complete solution is characterized by a function that must satisfy a single partial differential equation that is closely related to the Calabi-Yau condition. The deformation from a standard Calabi-Yau background is driven by a non-trivial, non-normalizable 3-form flux dual to a fermion mass that reduces the supersymmetry to N=1. This flux also induces dielectric polarization of the D3-branes into D5-branes.Comment: 22 pages; harvmac. Typos corrected;small improvements in presentatio

    Inhomogeneity of donor doping in SrTiO3 substrates studied by fluorescence-lifetime imaging microscopy

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    Fluorescence-lifetime imaging microscopy (FLIM) was applied to investigate the donor distribution in SrTiO3 single crystals. On the surfaces of Nb- and La-doped SrTiO3, structures with different fluorescence intensities and lifetimes were found that could be related to different concentrations of Ti3+. Furthermore, the inhomogeneous distribution of donors caused a non-uniform conductivity of the surface, which complicates the production of potential electronic devices by the deposition of oxide thin films on top of doped single crystals. Hence, we propose FLIM as a convenient technique (length scale: 1 ÎĽ\mum) for characterizing the quality of doped oxide surfaces, which could help to identify appropriate substrate materials

    Observation of interspecies Feshbach resonances in an ultracold Rb-Cs mixture

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    We report on the observation of interspecies Feshbach resonances in an ultracold, optically trapped mixture of Rb and Cs atoms. In a magnetic field range up to 300 G we find 23 interspecies Feshbach resonances in the lowest spin channel and 2 resonances in a higher channel of the mixture. The extraordinarily rich Feshbach spectrum suggests the importance of different partial waves in both the open and closed channels of the scattering problem along with higher-order coupling mechanisms. Our results provide, on one hand, fundamental experimental input to characterize the Rb-Cs scattering properties and, on the other hand, identify possible starting points for the association of ultracold heteronuclear RbCs molecules.Comment: 7 pages, 3 figures, 1 tabl

    Tumor necrosis factor-α-induced insulin resistance in 3T3-L1 adipocytes is accompanied by a loss of insulin receptor substrate-1 and GLUT4 expression without a loss of insulin receptor-mediated signal transduction

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    A number of studies have demonstrated that tumor necrosis factor-α (TNF-α) is associated with profound insulin resistance in adipocytes and may also play a critical role in the insulin resistance of obesity and non- insulin-dependent diabetes mellitus. Reports on the mechanism of TNF-α action have been somewhat contradictory. GLUT4 down-regulation has been implicated as a possible cause of insulin resistance as has been the reduced kinase function of the insulin receptor. Here we examine the effects of tumor necrosis factor on the protein components thought to be involved in insulin- stimulated glucose transport in adipocytes, namely the insulin receptor, its major substrate IRS-1, and the insulin responsive glucose transporter GLUT4. Prolonged exposure (72-96 h) of 3T3-L1 adipocytes to TNF-α causes a substantial reduction (\u3e 80%) in IRS-1 and GLUT4 mRNA and protein as well as a lesser reduction (\u3e50%) in the amount of the insulin receptor. Nevertheless, the remaining proteins appear to be biochemically indistinguishable from those in untreated adipocytes. Both the insulin receptor and IRS-1 are tyrosine-phosphorylated to the same extent in response to acute insulin stimulation following cellular TNF-α exposure. Furthermore, the ability of the insulin receptor to phosphorylate exogenous substrate in the test tube is also normal following its isolation from TNF-α-treated cells. These results are confirmed by the reduced but obvious level of insulin-dependent glucose transport and GLUT4 translocation observed in TNF- α-treated adipocytes. We conclude that the insulin resistance of glucose transport in 3T3-L1 adipocytes exposed to TNF-α for 72-96 h results from a reduced amount in requisite proteins involved in insulin action. These results are consistent with earlier studies indicating that TNF-α reduces the transcriptional activity of the GLUT4 gene in murine adipocytes, and reduced mRNA transcription of a number of relevant genes may be the general mechanism by which TNF-α causes insulin resistance in adipocytes

    The expression and regulation of STATs during 3T3-L1 adipocyte differentiation

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    STATs (Signal Transducers and Activators of Transcription) comprise a family of transcription factors that reside in the cytoplasm of resting cells. In response to a variety of stimuli, STATs become tyrosine- phosphorylated and translocate to the nucleus where they mediate transcriptional regulation. We have used the 3T3-L1 murine cell line to examine the expression of STAT proteins as a function of their differentiation into adipocytes. The expression of STATs 1, 3, and 5, but not of STAT 6, is markedly elevated in adipocytes as compared with their fibroblast precursors. Exposure of 3T3-L1 preadipocytes to tumor necrosis factor α (TNFα) blocks their differentiation into adipocytes. Therefore, we examined STAT expression as a function of differentiation in the presence of this cytokine. The expression of STATs 1 and 5 is markedly attenuated in the presence of TNFα, whereas STAT 3 expression is unaffected by this treatment. Only STAT 1 is down-regulated by TNFα in fully differentiated cells. Thus, although the expression of STATs 1, 3, and 5 is markedly enhanced upon differentiation, only STAT 5 expression is tightly correlated with the adipocyte phenotype. These data suggest that STAT 5, and possibly STAT 1, could be potential inducers of tissue-specific genes, which contribute to the development and maintenance of the adipocyte phenotype

    Expression and compartmentalization of caveolin in adipose cells: Coordinate regulation with and structural segregation from GLUT4

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    Native rat adipocytes and the mouse adipocyte cell line, 3T3-L1, possess transport vesicles of apparently uniform composition and size which translocate the tissue-specific glucose transporter isoform, GLUT4, from an intracellular pool to the cell surface in an insulin-sensitive fashion. Caveolin, the presumed structural protein of caveolae, has also been proposed to function in vesicular transport. Thus, we studied the expression and subcellular distribution of caveolin in adipocytes. We found that rat fat cells express the highest level of caveolin protein of any tissue studied, and caveolin is also expressed at high levels in cardiac muscle, another tissue possessing insulin responsive GLUT4 translocation. Both proteins are absent from 3T3-L1 fibroblasts and undergo a dramatic coordinate increase in expression upon differentiation of these cells into adipocytes. However, unlike GLUT4 in rat adipocytes not exposed to insulin, the majority of caveolin is present in the plasma membrane. In native rat adipocytes, intracellular GLUT4 and caveolin reside in vesicles practically indistinguishable by their size and buoyant density in sucrose gradients, and both proteins show insulin-dependent translocation to the cell surface. However, by immunoadsorption of GLUT4-containing vesicles with anti-GLUT4 antibody, we show that these vesicles have no detectable caveolin, and therefore, this protein is present in a distinct vesicle population. Thus, caveolin has no direct structural relation to the organization of the intracellular glucose transporting machinery in fat cells

    Supersymmetric Charged Clouds in AdS_5

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    We consider supersymmetric holographic flows that involve background gauge fields dual to chemical potentials in the boundary field theory. We use a consistent truncation of gauged N=8 supergravity in five dimensions and we give a complete analysis of the supersymmetry conditions for a large family of flows. We examine how the well-known supersymmetric flow between two fixed points is modified by the presence of the chemical potentials and this yields a new, completely smooth, solution that interpolates between two global AdS spaces of different radii and with different values of the chemical potential. We also examine some black-hole-like singular flows and a new non-supersymmetric black hole solution. We comment on the interpretation of our new solutions in terms of giant gravitons and discuss the implications of our work for finding black-hole solutions in AdS geometries.Comment: 31 pages, 6 figures; minor corrections, updated reference

    Clinical Pain Scale Compendium

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    Title: Clinical Pain Scale Compendium Authors: James Aiken, SPT1, Tiffany Crow, SPT1, Nicholas Pilch, SPT1 Affiliation(s): 1. Physical Therapy Program, University of Puget Sound Theory: Pain is one of the pivotal aspects of a healthcare examination. Clinicians cannot measure pain objectively, and thus, we can only obtain a subjective report of the patient’s experience. However, the human experience of pain can be measured beyond merely its intensity. The purpose of this compendium is to present a range of pain aspects; the who, what, where, when, and how much of pain measurement. This is accomplished with the following domains: affective, beliefs, intensity, sensory quality, location, temporal, impact on activities of daily living, and population. The aim of this compendium is to present a model of various pain dimensions and to expand the number of tools available to measure pain, as pain can mean different things. It is novel in its breadth of coverage of pain scales and comprehensive summarization for ease of use. With an improved capacity of pain measurement tools available, clinicians can better correlate care with more accurate pain assessments to meet a patient’s unique needs. In conclusion, we have compiled these measures to provide additional pain evaluation tools for physical therapists and other medical professionals in order to improve patient care
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