745 research outputs found

    Quantum gravitational optics in the field of a gravitomagnetic monopole

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    Vacuum polarization in QED in a background gravitational field induces interactions which {\it effectively} modify the classical picture of light rays as the null geodesics of spacetime. After a short introduction on the main aspects of the quantum gravitational optics, as a nontrivial example, we study this effect in the background of NUT space characterizing the spacetime of a spherical mass endowed with a gravitomagnetic monopole charge, the so called NUT factor.Comment: 9 pages, title changed and the text abridged for publication in the Journal of Physics: Conference serie

    The transcription factor Etv5 controls TH17 cell development and allergic airway inflammation

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    Background The differentiation of TH17 cells, which promote pulmonary inflammation, requires the cooperation of a network of transcription factors. Objectives We sought to define the role of Etv5, an Ets-family transcription factor, in TH17 cell development and function. Methods TH17 development was examined in primary mouse T cells wherein Etv5 expression was altered by retroviral transduction, small interfering RNA targeting a specific gene, and mice with a conditional deletion of Etv5 in T cells. The direct function of Etv5 on the Il17 locus was tested with chromatin immunoprecipitation and reporter assays. The house dust mite–induced allergic inflammation model was used to test the requirement for Etv5-dependent TH17 functions in vivo. Results We identify Etv5 as a signal transducer and activator of transcription 3–induced positive regulator of TH17 development. Etv5 controls TH17 differentiation by directly promoting 0a and Il17f expression. Etv5 recruits histone-modifying enzymes to the Il17a–Il17f locus, resulting in increased active histone marks and decreased repressive histone marks. In a model of allergic airway inflammation, mice with Etv5-deficient T cells have reduced airway inflammation and IL-17A/F production in the lung and bronchoalveolar lavage fluid compared with wild-type mice, without changes in TH2 cytokine production. Conclusions These data define signal transducer and activator of transcription 3–dependent feed-forward control of TH17 cytokine production and a novel role for Etv5 in promoting T cell–dependent airway inflammation

    Contemporary outcome measures in acute stroke research: choice of primary outcome measure

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    BACKGROUND AND PURPOSE: The diversity of available outcome measures for acute stroke trials is challenging and implies that the scales may be imperfect. To assist researchers planning trials and to aid interpretation, this article reviews and makes recommendations on the available choices of scales. The aim is to identify an approach that will be universally accepted and that should be included in most acute trials, without seeking to restrict options for special circumstances. METHODS: The article considers outcome measures that have been widely used or are currently advised. It examines desirable properties for outcome measures such as validity, relevance, responsiveness, statistical properties, availability of training, cultural and language issues, resistance to comorbidity, as well as potential weaknesses. Tracking and agreement among outcomes are covered. RESULTS: Typical ranges of scores for the common scales are described, along with their statistical properties, which in turn influence optimal analytic techniques. The timing of recovery on scores and usual practice in trial design are considered. CONCLUSIONS: The preferred outcome measure for acute trials is the modified Rankin Scale, assessed at 3 months after stroke onset or later. The interview should be conducted by a certified rater and should involve both the patient and any relevant caregiver. Incremental benefits at any level of the modified Rankin Scale may be acceptable. The modified Rankin Scale is imperfect but should be retained in its present form for comparability with existing treatment comparisons. No second measure should be required, but correlations with supporting scales may be used to confirm consistency in direction of effects on other measures

    Instrumentation of Earth Rock Fill Dams

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    An effective instrumentation and monitoring program combined with regular inspection are the key factors of a good dam safety program. Instrumentation data can be of benefit only if the instruments function reliably, the data are received and evaluated in a timely manner and values are compared to the documented design limits and historical behavior

    Supercurrent Flow in NJL_{2+1} at High Baryon Density

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    We present results of numerical simulations of the 2+1d Nambu -- Jona-Lasinio model with non-zero baryon chemical potential mu and spatially-varying complex diquark source strength j. By choosing arg(j) to vary smoothly through 2 pi across the spatial extent of the lattice, a baryon number current is induced which in the high density phase remains non-vanishing as |j|->0; we are hence able to extract a quantity characteristic of a superfluid known as the helicity modulus. We also study supercurrent flow at non-zero temperature and estimate the critical temperature at which the normal phase is restored, which is consistent with the conventional picture for thin-film superfluids in which the transition is viewed in terms of vortex -- anti-vortex unbinding.Comment: 10 pages, 5 figure

    TH9 cells are required for tissue mast cell accumulation during allergic inflammation

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    BACKGROUND: IL-9 is important for the growth and survival of mast cells. IL-9 is produced by T cells, natural killer T cells, mast cells, eosinophils, and innate lymphoid cells, although the cells required for mast cell accumulation during allergic inflammation remain undefined. OBJECTIVE: We sought to elucidate the role of TH9 cells in promoting mast cell accumulation in models of allergic lung inflammation. METHODS: Adoptive transfer of ovalbumin-specific TH2 and TH9 cells was used to assess the ability of each subset to mediate mast cell accumulation in tissues. Mast cell accumulation was assessed in wild-type mice and mice with PU.1-deficient T cells subjected to acute and chronic models of allergic inflammation. RESULTS: Adoptive transfer experiments demonstrated that recipients of TH9 cells had significantly higher mast cell accumulation and expression of mast cell proteases compared with control or TH2 recipients. Mast cell accumulation was dependent on IL-9, but not IL-13, a cytokine required for many aspects of allergic inflammation. In models of acute and chronic allergic inflammation, decreased IL-9 levels in mice with PU.1-deficient T cells corresponded to diminished tissue mast cell numbers and expression of mast cell proteases. Mice with PU.1-deficient T cells have defects in IL-9 production from CD4(+) T cells, but not natural killer T cells or innate lymphoid cells, suggesting a TH cell-dependent phenotype. Rag1(-/-) mice subjected to a chronic model of allergic inflammation displayed reduced mast cell infiltration comparable with accumulation in mice with PU.1-deficient T cells, emphasizing the importance of IL-9 produced by T cells in mast cell recruitment. CONCLUSION: TH9 cells are a major source of IL-9 in models of allergic inflammation and play an important role in mast cell accumulation and activation
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