340 research outputs found

    EXPERIMENTAL EVALUATION OF THE PULMONARY EDEMA INDUCED BY THE VENOM OF THE SCORPION TITYUS ASTHENES IN RATS

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    The species Tityus asthenes has been responsible for scorpion sting deaths in Panama. Pulmonary edema is one of the main causes of death registered by scorpionism. In the present work, we determined the capacity of the venom of the scorpion Tityus asthenes to induce pulmonary edema in rats. The ability of T. asthenes venom to induce acute pulmonary edema in rats was determined using four approaches: (1) the difference in wet weight using the lung index between treated and untreated lungs; (2) histological analysis; (3) changes in pulmonary vascular permeability; and (4) total leukocyte count obtained from bronchoalveolar lavage. We found that histological sections of venom-treated lungs showed moderate pulmonary edema, and an increase in total leukocyte count compared to control samples. However, the pulmonary index and the vascular permeability of venom-treated lungs were similar to those of control samples. We conclude that the venom of T. asthenes scorpions can induce moderate pulmonary edema in rats. The experimental model was validated for future studies on the pathophysiology of pulmonary edema caused by the venom of scorpions of the genus Tityus in Panama

    Controlled transdermal release of antioxidant ferulate by a porous Sc(III) MOF

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    The Sc(III) MOF-type MFM-300(Sc) is demonstrated in this study to be stable under physiological conditions (PBS), biocompatible (to human skin cells), and an efficient drug carrier for the long-term controlled release (through human skin) of antioxidant ferulate. MFM-300(Sc) also preserves the antioxidant pharmacological effects of ferulate while enhancing the bio-preservation of dermal skin fibroblasts, during the delivery process. These discoveries pave the way toward the extended use of Sc(III)-based MOFs as drug delivery systems (DDSs)

    The molecular basis and biologic significance of the β-dystroglycan-emerin interaction

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    β-dystroglycan (β-DG) assembles with lamins A/C and B1 and emerin at the nuclear envelope (NE) to maintain proper nuclear architecture and function. To provide insight into the nuclear function of β-DG, we characterized the interaction between β-DG and emerin at the molecular level. Emerin is a major NE protein that regulates multiple nuclear processes and whose deficiency results in Emery–Dreifuss muscular dystrophy (EDMD). Using truncated variants of β-DG and emerin, via a series of in vitro and in vivo binding experiments and a tailored computational analysis, we determined that the β-DG–emerin interaction is mediated at least in part by their respective transmembrane domains (TM). Using surface plasmon resonance assays we showed that emerin binds to β-DG with high affinity (KD in the nanomolar range). Remarkably, the analysis of cells in which DG was knocked out demonstrated that loss of β-DG resulted in a decreased emerin stability and impairment of emerin-mediated processes. β-DG and emerin are reciprocally required for their optimal targeting within the NE, as shown by immunofluorescence, western blotting and immunoprecipitation assays using emerin variants with mutations in the TM domain and B-lymphocytes of a patient with EDMD. In summary, we demonstrated that β-DG plays a role as an emerin interacting partner modulating its stability and function

    The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Analysis of potential systematics

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    We analyze the density field of galaxies observed by the Sloan Digital Sky Survey (SDSS)-III Baryon Oscillation Spectroscopic Survey (BOSS) included in the SDSS Data Release Nine (DR9). DR9 includes spectroscopic redshifts for over 400,000 galaxies spread over a footprint of 3,275 deg^2. We identify, characterize, and mitigate the impact of sources of systematic uncertainty on large-scale clustering measurements, both for angular moments of the redshift-space correlation function and the spherically averaged power spectrum, P(k), in order to ensure that robust cosmological constraints will be obtained from these data. A correlation between the projected density of stars and the higher redshift (0.43 < z < 0.7) galaxy sample (the `CMASS' sample) due to imaging systematics imparts a systematic error that is larger than the statistical error of the clustering measurements at scales s > 120h^-1Mpc or k < 0.01hMpc^-1. We find that these errors can be ameliorated by weighting galaxies based on their surface brightness and the local stellar density. We use mock galaxy catalogs that simulate the CMASS selection function to determine that randomly selecting galaxy redshifts in order to simulate the radial selection function of a random sample imparts the least systematic error on correlation function measurements and that this systematic error is negligible for the spherically averaged correlation function. The methods we recommend for the calculation of clustering measurements using the CMASS sample are adopted in companion papers that locate the position of the baryon acoustic oscillation feature (Anderson et al. 2012), constrain cosmological models using the full shape of the correlation function (Sanchez et al. 2012), and measure the rate of structure growth (Reid et al. 2012). (abridged)Comment: Matches version accepted by MNRAS. Clarifications and references have been added. See companion papers that share the "The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey:" titl

    Search for Top Squark Pair Production in the Dielectron Channel

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    This report describes the first search for top squark pair production in the channel stop_1 stopbar_1 -> b bbar chargino_1 chargino_1 -> ee+jets+MEt using 74.9 +- 8.9 pb^-1 of data collected using the D0 detector. A 95% confidence level upper limit on sigma*B is presented. The limit is above the theoretical expectation for sigma*B for this process, but does show the sensitivity of the current D0 data set to a particular topology for new physics.Comment: Five pages, including three figures, submitted to PRD Brief Report

    Search for bottom squarks in pbarp collisions at sqrt(s)=1.8 TeV

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    We report on a search for bottom squarks produced in pbarp collisions at sqrt(s) = 1.8 TeV using the D0 detector at Fermilab. Bottom squarks are assumed to be produced in pairs and to decay to the lightest supersymmetric particle (LSP) and a b quark with branching fraction of 100%. The LSP is assumed to be the lightest neutralino and stable. We set limits on the production cross section as a function of bottom squark mass and LSP mass.Comment: 5 pages, Latex. submitted 3-12-1999 to PRD - Rapid Communicatio

    Search for Squarks and Gluinos in Events Containing Jets and a Large Imbalance in Transverse Energy

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    Using data corresponding to an integrated luminosity of 79 pb-1, D0 has searched for events containing multiple jets and large missing transverse energy in pbar-p collisions at sqrt(s)=1.8 TeV at the Fermilab Tevatron collider. Observing no significant excess beyond what is expected from the standard model, we set limits on the masses of squarks and gluinos and on the model parameters m_0 and m_1/2, in the framework of the minimal low-energy supergravity models of supersymmetry. For tan(beta) = 2 and A_0 = 0, with mu < 0, we exclude all models with m_squark < 250 GeV/c^2. For models with equal squark and gluino masses, we exclude m < 260 GeV/c^2.Comment: 10 pages, 3 figures, Submitted to PRL, Fixed typo on page bottom of p. 6 (QCD multijet background is 35.4 events

    Differential Production Cross Section of Z Bosons as a Function of Transverse Momentum at sqrt{s}=1.8 TeV

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    We present a measurement of the transverse momentum distribution of Z bosons produced in ppbar collisions at sqrt{s}=1.8 TeV using data collected by the D0 experiment at the Fermilab Tevatron Collider during 1994--1996. We find good agreement between our data and a current resummation calculation. We also use our data to extract values of the non-perturbative parameters for a particular version of the resummation formalism, obtaining significantly more precise values than previous determinations.Comment: 10 pages, 2 figures, submitted to Phys. Rev. Letters v2 has margin error correcte

    Measurement of the WW Boson Mass

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    A measurement of the mass of the WW boson is presented based on a sample of 5982 WeνW \rightarrow e \nu decays observed in ppp\overline{p} collisions at s\sqrt{s} = 1.8~TeV with the D\O\ detector during the 1992--1993 run. From a fit to the transverse mass spectrum, combined with measurements of the ZZ boson mass, the WW boson mass is measured to be MW=80.350±0.140(stat.)±0.165(syst.)±0.160(scale)GeV/c2M_W = 80.350 \pm 0.140 (stat.) \pm 0.165 (syst.) \pm 0.160 (scale) GeV/c^2.Comment: 12 pages, LaTex, style Revtex, including 3 postscript figures (submitted to PRL

    Direct Measurement of the Top Quark Mass at D0

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    We determine the top quark mass m_t using t-tbar pairs produced in the D0 detector by \sqrt{s} = 1.8 TeV p-pbar collisions in a 125 pb^-1 exposure at the Fermilab Tevatron. We make a two constraint fit to m_t in t-tbar -> b W^+bbar W^- final states with one W boson decaying to q-qbar and the other to e-nu or mu-nu. Likelihood fits to the data yield m_t(l+jets) = 173.3 +- 5.6 (stat) +- 5.5 (syst) GeV/c^2. When this result is combined with an analysis of events in which both W bosons decay into leptons, we obtain m_t = 172.1 +- 5.2 (stat) +- 4.9 (syst) GeV/c^2. An alternate analysis, using three constraint fits to fixed top quark masses, gives m_t(l+jets) = 176.0 +- 7.9 (stat) +- 4.8 (syst) GeV/C^2, consistent with the above result. Studies of kinematic distributions of the top quark candidates are also presented.Comment: 43 pages, 53 figures, 33 tables. RevTeX. Submitted to Phys. Rev.
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