1,023 research outputs found

    In vivo Detection of Hyperoxia-induced Pulmonary Endothelial Cell Death Using \u3csup\u3e99m\u3c/sup\u3eTc-Duramycin

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    Introduction 99mTc-duramycin, DU, is a SPECT biomarker of tissue injury identifying cell death. The objective of this study is to investigate the potential of DU imaging to quantify capillary endothelial cell death in rat lung injury resulting from hyperoxia exposure as a model of acute lung injury. Methods Rats were exposed to room air (normoxic) or \u3e 98% O2 for 48 or 60 hours. DU was injected i.v. in anesthetized rats, scintigraphy images were acquired at steady-state, and lung DU uptake was quantified from the images. Post-mortem, the lungs were removed for histological studies. Sequential lung sections were immunostained for caspase activation and endothelial and epithelial cells. Results Lung DU uptake increased significantly (p \u3c 0.001) by 39% and 146% in 48-hr and 60-hr exposed rats, respectively, compared to normoxic rats. There was strong correlation (r2 = 0.82, p = 0.005) between lung DU uptake and the number of cleaved caspase 3 (CC3) positive cells, and endothelial cells accounted for more than 50% of CC3 positive cells in the hyperoxic lungs. Histology revealed preserved lung morphology through 48 hours. By 60 hours there was evidence of edema, and modest neutrophilic infiltrate. Conclusions Rat lung DU uptake in vivo increased after just 48 hours of \u3e 98% O2 exposure, prior to the onset of any substantial evidence of lung injury. These results suggest that apoptotic endothelial cells are the primary contributors to the enhanced DU lung uptake, and support the utility of DU imaging for detecting early endothelial cell death in vivo

    Practical reasoning in political discourse: The UK government's response to the economic crisis in the 2008 Pre-Budget Report

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    This article focuses on practical reasoning in political discourse and argues for a better integration of argumentation theory with critical discourse analysis (CDA). Political discourse and its specific genres (for example, deliberation) primarily involve forms of practical reasoning, typically oriented towards finding solutions to problems and deciding on future courses of action. Practical reasoning is a form of inference from cognitive and motivational premises: from what we believe (about the situation or about means—end relations) and what we want or desire (our goals and values), leading to a normative judgement (and often a decision) concerning action. We offer an analysis of the main argument in the UK government’s 2008 Pre-Budget Report (HM Treasury, 2008) and suggest how a critical evaluation of the argument from the perspective of a normative theory of argumentation (particularly the informal logic developed by Douglas Walton) can provide the basis for an evaluation in terms of characteristic CDA concerns. We are advancing this analysis as a contribution to CDA, aimed at increasing the rigour and systematicity of its analyses of political discourse, and as a contribution to the normative concerns of critical social science

    Anomalous Behavior of 2+ Excitations around 132Sn

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    In certain neutron-rich Te isotopes, a decrease in the energy of the first excited 2+ state is accompanied by a decrease in the E2 strength to that state from the ground state, contradicting simple systematics and general intuition about quadrupole collectivity. We use a separable quadrupole-plus-pairing Hamiltonian and the quasiparticle random phase approximation to calculate energies, B(E2,0+ -> 2+) strengths, and g factors for the lowest 2+ states near 132Sn (Z >= 50). We trace the anomalous behavior in the Te isotopes to a reduced neutron pairing above the N = 82 magic gap.Comment: 1 figure added. to be published in Phys. Rev.

    Low momentum nucleon-nucleon potential and shell model effective interactions

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    A low momentum nucleon-nucleon (NN) potential V-low-k is derived from meson exhange potentials by integrating out the model dependent high momentum modes of V_NN. The smooth and approximately unique V-low-k is used as input for shell model calculations instead of the usual Brueckner G matrix. Such an approach eliminates the nuclear mass dependence of the input interaction one finds in the G matrix approach, allowing the same input interaction to be used in different nuclear regions. Shell model calculations of 18O, 134Te and 135I using the same input V-low-k have been performed. For cut-off momentum Lambda in the vicinity of 2 fm-1, our calculated low-lying spectra for these nuclei are in good agreement with experiments, and are weakly dependent on Lambda.Comment: 5 pages, 5 figure

    Q_EC values of the Superallowed beta-Emitters 10-C, 34-Ar, 38-Ca and 46-V

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    The Q_EC values of the superallowed beta+ emitters 10-C, 34-Ar, 38-Ca and 46-V have been measured with a Penning-trap mass spectrometer to be 3648.12(8), 6061.83(8), 6612.12(7) and 7052.44(10) keV, respectively. All four values are substantially improved in precision over previous results.Comment: 9 pages, 7 figures, 5 table

    Equation of state for nuclear matter based on density dependent effective interaction

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    An interesting method of obtaining equation of state for nuclear matter, from a density dependent M3Y interaction, by minimizing the energy per nucleon is described. The density dependence parameters of the interaction are obtained by reproducing the saturation energy per nucleon and the saturation density of spin and isospin symmetric cold infinite nuclear matter. The nuclear matter equation of state thus obtained is then used to calculate the pressure, the energy density, the nuclear incompressibility and the velocity of sound in nuclear medium. The results obtained are in good agreement with experimental data and provide a unified description of radioactivity, scattering and nuclear matter.Comment: 10 pages including 2 figure

    Generalized seniority scheme in light Sn isotopes

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    The yrast generalized seniority states are compared with the corresponding shell model states for the case of the Sn isotopes 104112^{104-112}Sn. For most of the cases the energies agree within 100 keV and the overlaps of the wave functions are greater than 0.7.Comment: 8 pages, revtex. Submitted to Phys. Rev.

    Q-Value for the Fermi Beta-Decay of 46V

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    By comparing the Q-values for the 46Ti(3He,t)46V and 47Ti(3He,t)47}V reactions to the isobaric analog states the Q-value for the superallowed Fermi-decay of 46V has been determined as Q_{EC}(46V)=(7052.11+/-0.27) keV. The result is compatible with the values from two recent direct mass measurements but is at variance with the previously most precise reaction Q-value. As additional input quantity we have determined the neutron separation energy S_n(47Ti)=(8880.51+/-0.25) keV

    Nuclear Structure based on Correlated Realistic Nucleon-Nucleon Potentials

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    We present a novel scheme for nuclear structure calculations based on realistic nucleon-nucleon potentials. The essential ingredient is the explicit treatment of the dominant interaction-induced correlations by means of the Unitary Correlation Operator Method (UCOM). Short-range central and tensor correlations are imprinted into simple, uncorrelated many-body states through a state-independent unitary transformation. Applying the unitary transformation to the realistic Hamiltonian leads to a correlated, low-momentum interaction, well suited for all kinds of many-body models, e.g., Hartree-Fock or shell-model. We employ the correlated interaction, supplemented by a phenomenological correction to account for genuine three-body forces, in the framework of variational calculations with antisymmetrised Gaussian trial states (Fermionic Molecular Dynamics). Ground state properties of nuclei up to mass numbers A<~60 are discussed. Binding energies, charge radii, and charge distributions are in good agreement with experimental data. We perform angular momentum projections of the intrinsically deformed variational states to extract rotational spectra.Comment: 32 pages, 15 figure

    Examining exotic structure of proton-rich nucleus 23^{23}Al

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    The longitudinal momentum distribution (P_{//}) of fragments after one-proton removal from ^{23} Al and reaction cross sections (\sigma_R) for ^{23,24} Al on carbon target at 74A MeV have been measured. The ^{23,24} Al ions were produced through projectile fragmentation of 135 A MeV ^{28} Si primary beam using RIPS fragment separator at RIKEN. P_{//} is measured by a direct time-of-flight (TOF) technique, while \sigma_R is determined using a transmission method. An enhancement in \sigma_R is observed for ^{23} Al compared with ^{24} Al. The P_{//} for ^{22} Mg fragments from ^{23} Al breakup has been obtained for the first time. FWHM of the distributions has been determined to be 232 \pm 28 MeV/c. The experimental data are discussed by using Few-Body Glauber model. Analysis of P_{//} demonstrates a dominant d-wave configuration for the valence proton in ground state of ^{23} Al, indicating that ^{23} Al is not a proton halo nucleus
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