4,038 research outputs found

    Influence of target material impurities on physical results in relativistic heavy-ion collisions

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    This paper presents the studies on the influence of the target material impurities on physical observables registered in heavy ion collisions collected by fixed target experiments. It mainly concerns the measures of multiplicity fluctuations which can be used to searches for critical point of strongly interacting matter, e.g. in the {NA61/SHINE} fixed-target experiment at CERN SPS. The elemental composition of the targets used in the NA61/SHINE experiment was determined applying wavelength dispersive X-ray fluorescence (WDXRF) technique. The influence of measured target impurities on multiplicity distributions and scaled variance was estimated using simulation events. The modification of the standard analysis was proposed to reduce this influence.Comment: 12 pages, 11 figure

    Immune status of recipients following bone marrow - Augmented solid organ transplantation

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    It has been postulated that the resident “passenger” leukocytes of hematolymphoid origin that migrate from whole organ grafts and subsequently establish systemic chimerism are essential for graft acceptance and the induction of donor-specific nonreactivity. This phenomenon was augmented by infusing 3 × 108 unmodified donor bone-marrow cells into 40 patients at the time of organ transplantation. Fifteen of the first 18 analyzable patients had sequential immunological evaluation over postoperative intervals of 5 to 17 months, (which included 7 kidney (two with islets), 7 liver (one with islets), and one heart recipient). The evolution of changes was compared with that in 16 kidney and liver nonmarrow controls followed for 4 to5 months. The generic immune reactivity of peripheral blood mononuclear cells (PBMC) was determined by their proliferative responses to mitogens (PHA, ConA). Alloreactivity was measured by the recipient mixed lymphocyte reaction (MLR) to donor and HLA-mis-matched third-party panel cells. Based on all 3 tests,the recipients were classified as donor-specific hyporeactive, intermediate, and responsive; patients who were globally suppressed made up a fourth category. Eight (53%) of the 15 marrow-treated recipients exhibited progressive modulation of donor-specific reactivity (3 hyporeactive and 5 intermediate) while 7 remained antidonor-responsive. In the nonmarrow controls, 2 (12.5%) of the 16 patients showed donor-specific hyporeactivity, 10 (62.5%) were reactive, and 4 (25%) studied during a CMV infection had global suppression of responsiveness to all stimuli. © 1995 by Williams and Wilkins

    Subchronic Hepatotoxicity Evaluation of 2,3,4,6-Tetrachlorophenol in Sprague Dawley Rats

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    Male Sprague Dawley rats were exposed to 2,3,4,6-tetrachlorophenol (TCP) for 5 days, 2 weeks, 4 weeks, or 13 weeks. TCP was administered by gavage at doses of 0, 10, 25, 50, 100, or 200 mg/kg/day. Endpoints evaluated included clinical observations, body weights, liver weights, serum chemistry, blood TCP, gross pathology, and liver histopathology. There were no TCP exposure-related clinical signs of toxicity. Mean body weight decreased 12–22% compared to control in the 100 and 200 mg/kg/day groups. Serum ALT concentrations were increased in rats of the 200 mg/k/day. Liver weight increases were both dose- and exposure time-related and statistically significant at ≥25 mg/kg/day. Incidence and severity of centrilobular hepatocytic vacuolation, hepatocyte hypertrophy, and single cell hepatocytic necrosis were related to dose and exposure time. Following 13 weeks of exposure, bile duct hyperplasia and centrilobular and/or periportal fibrosis were observed in rats primarily of the highest TCP dose group. Blood TCP concentrations increased with dose and at 13 weeks ranged from 1.3 to 8.5 μg/mL (10 to 200 mg/kg/day). A NOAEL of 10 mg/kg/day was selected based on the statistically significant incidence of hepatocyte hypertrophy at doses ≥25 mg/kg/day

    How conceptualising obesity as a disease affects beliefs about weight, and associated weight stigma and clinical decision-making in health care

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    Objectives: This study empirically investigated how conceptualizing obesity as a disease (i.e., pathologizing obesity) affects beliefs about weight, and weight stigma and discrimination among health professionals. Design: An experiment that manipulated the pathologization of obesity was completed by a multi-nation sample of health professionals from Australia, UK, and USA (N = 365). Methods: Participants were randomly assigned to one of two conditions where they were asked to conceptualize obesity as a disease or not a disease; then presented with a hypothetical medical profile of a patient with obesity who was seeking care for migraines. We measured biogenetic causal beliefs about obesity, endorsement of weight as a heuristic for health, negative obesity stereotypes, and treatment decisions. Results: Participants in the disease (vs. non-disease) condition endorsed biogenetic causal beliefs more strongly and made more migraine-related treatment recommendations. No effect of the manipulation was found for the remaining outcomes. Biogenetic causal beliefs about obesity were associated with less weight stigma. Endorsing weight as a heuristic for health was associated with greater weight stigma and differential treatment recommendations focused more on the patient's weight and less on their migraines. Conclusions: Pathologizing obesity may reinforce biogenetic explanations for obesity. Evidence demonstrates complex associations between weight-related beliefs and weight stigma and discrimination. Biogenetic causal beliefs were associated with less weight stigma, while endorsing weight as a heuristic for health was associated with greater weight stigma and differential treatment. Further research is needed to inform policies that can promote health without perpetuating weight-based rejection in health care

    Fitting Corrections to an RNA Force Field Using Experimental Data

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    Empirical force fields for biomolecular systems are usually derived from quantum chemistry calculations and validated against experimental data. We here show how it is possible to refine the full dihedral-angle potential of the Amber RNA force field by using solution NMR data as well as stability of known structural motifs. The procedure can be used to mix multiple systems and heterogeneous experimental information and crucially depends on a regularization term chosen with a cross-validation procedure. By fitting corrections to the dihedral angles on the order of less than 1 kJ/mol per angle, it is possible to increase the stability of difficult-to-fold RNA tetraloops by more than 1 order of magnitude
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