831 research outputs found

    Phasespace Correlations of Antideuterons in Heavy Ion Collisions

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    In the framework of the relativistic quantum molecular dynamics approach ({\small RQMD}) we investigate antideuteron (d‾\overline{d}) observables in Au+Au collisions at 10.7~AGeV. The impact parameter dependence of the formation ratios d‾/p‾2\overline{d}/\overline{p}^2 and d/p2{d}/{p}^2 is calculated. In central collisions, the antideuteron formation ratio is predicted to be two orders of magnitude lower than the deuteron formation ratio. The d‾\overline{d} yield in central Au+Au collisions is one order of magnitude lower than in Si+Al collisions. In semicentral collisions different configuration space distributions of p‾\overline{p}'s and d‾\overline{d}'s lead to a large ``squeeze--out'' effect for antideuterons, which is not predicted for the p‾\overline{p}'s

    Antibaryons in massive heavy ion reactions: Importance of potentials

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    In the framework of RQMD we investigate antiproton observables in massive heavy ion collisions at AGS energies and compare to preliminary results of the E878 collaboration. We focus here on the considerable influence of the *real* part of an antinucleon--nucleus optical potential on the antiproton momentum spectra

    Unmasking features of the auto-epitope essential for β(1)-adrenoceptor activation by autoantibodies in chronic heart failure

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    AIMS: Chronic heart failure (CHF) can be caused by autoantibodies stimulating the heart via binding to first and/or second extracellular loops of cardiac β(1)-adrenoceptors. Allosteric receptor activation depends on conformational features of the autoantibody binding site. Elucidating these features will pave the way for the development of specific diagnostics and therapeutics. Our aim was (i) to fine-map the conformational epitope within the second extracellular loop of the human β(1)-adrenoceptor (β(1) EC(II)) that is targeted by stimulating β(1)-receptor (auto)antibodies and (ii) to generate competitive cyclopeptide inhibitors of allosteric receptor activation, which faithfully conserve the conformational auto-epitope. METHODS AND RESULTS: Non-conserved amino acids within the β(1) ECII loop (compared with the amino acids constituting the ECII loop of the β(2)-adrenoceptor) were one by one replaced with alanine; potential intra-loop disulfide bridges were probed by cysteine-serine exchanges. Effects on antibody binding and allosteric receptor activation were assessed (i) by (auto)antibody neutralization using cyclopeptides mimicking β(1) ECII ± the above replacements, and (ii) by (auto)antibody stimulation of human β(1)-adrenoceptors bearing corresponding point mutations. With the use of stimulating β(1)-receptor (auto)antibodies raised in mice, rats, or rabbits and isolated from exemplary dilated cardiomyopathy patients, our series of experiments unmasked two features of the β(1) ECII loop essential for (auto)antibody binding and allosteric receptor activation: (i) the NDPK(211-214) motif and (ii) the intra-loop disulfide bond C(209)↔C(215). Of note, aberrant intra-loop disulfide bond C(209)↔C(216) almost fully disrupted the functional auto-epitope in cyclopeptides. CONCLUSIONS: The conformational auto-epitope targeted by cardio-pathogenic β(1)-receptor autoantibodies is faithfully conserved in cyclopeptide homologues of the β(1) EC(II) loop bearing the NDPK(211-214) motif and the C(209)↔C(215) bridge while lacking cysteine C(216). Such molecules provide promising tools for novel diagnostic and therapeutic approaches in β(1)-autoantibody-positive CHF

    The rodent research animal holding facility as a barrier to environmental contamination

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    The rodent Research Animal Holding Facility (RAHF), developed by NASA Ames Research Center (ARC) to separately house rodents in a Spacelab, was verified as a barrier to environmental contaminants during a 12-day biocompatibility test. Environmental contaminants considered were solid particulates, microorganisms, ammonia, and typical animal odors. The 12-day test conducted in August 1988 was designed to verify that the rodent RAHF system would adequately support and maintain animal specimens during normal system operations. Additional objectives of this test were to demonstrate that: (1) the system would capture typical particulate debris produced by the animal; (2) microorganisms would be contained; and (3) the passage of animal odors was adequately controlled. In addition, the amount of carbon dioxide exhausted by the RAHF system was to be quantified. Of primary importance during the test was the demonstration that the RAHF would contain particles greater than 150 micrometers. This was verified after analyzing collection plates placed under exhaust air ducts and rodent cages during cage maintenance operations, e.g., waste tray and feeder changeouts. Microbiological testing identified no additional organisms in the test environment that could be traced to the RAHF. Odor containment was demonstrated to be less than barely detectable. Ammonia could not be detected in the exhaust air from the RAHF system. Carbon dioxide levels were verified to be less than 0.35 percent

    Bacterial Cholangitis, Cholecystitis, or both in Dogs

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    BACKGROUND: Bacterial cholangitis and cholecystitis are rarely reported, poorly characterized diseases in the dog. OBJECTIVES: To characterize the clinical features of these conditions. ANIMALS: Twenty‐seven client‐owned dogs with bacterial cholangitis, cholecystitis, or both. METHODS: Multicenter, retrospective cases series of dogs with bacterial cholangitis, cholecystitis, or both, presenting January 2000 to June 2011 to 4 Veterinary Schools in Ireland/United Kingdom. Interrogation of hospital databases identified all cases with the inclusion criteria; histopathologically confirmed cholangitis or cholecystitis and bile culture/cytology results supporting a bacterial etiology. RESULTS: Twenty‐seven dogs met the inclusion criteria with approximately 460 hepatitis cases documented over the same study period. Typical clinical pathology findings were increases in liver enzyme activities (25/26), hyperbilirubinemia (20/26), and an inflammatory leukogram (21/24). Ultrasound findings, although nonspecific, aided decision‐making in 25/26 cases. The most frequent hepatobiliary bacterial isolates were Escherichia coli (n = 17; 16 cases), Enterococcus spp. (n = 8; 6 cases), and Clostridium spp. (n = 5; 5 cases). Antimicrobial resistance was an important feature of aerobic isolates; 10/16 E. coli isolates resistant to 3 or more antimicrobial classes. Biliary tract rupture complicated nearly one third of cases, associated with significant mortality (4/8). Discharged dogs had a guarded to fair prognosis; 17/18 alive at 2 months, although 5/10 re‐evaluated had persistent liver enzyme elevation 2–12 months later. CONCLUSION AND CLINICAL SIGNIFICANCE: Bacterial cholangitis and cholecystitis occur more frequently than suggested by current literature and should be considered in dogs presenting with jaundice and fever, abdominal pain, or an inflammatory leukogram or with ultrasonographic evidence of gallbladder abnormalities

    Retroreflector array as a tapped delay-line filter for ultra-short optical pulses

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    A retroreflector array can be used to act as an optical tapped delay-line filter for temporal optical signals. Here, we demonstrate the basic operation and present a theoretical description. Our theory is based on the mathematical formalism for finite impulse response filters. A relationship to the classical Talbot bands experiment is established. By adding a mask to the retroreflector array, one can implement arbitrary filter operations. As a specific example, a differentiation in frequency domain is demonstrated by using a simple binary mask. The proposed devise maybe useful for the optical filtering and shaping of ultra short pulses

    Surface PM machine parameter selection for wide field-weakening applications

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    Recent work on fractional-slot pitch, concentrated winding (FSCW) surface PM machines has shown that these machines can achieve a wide constant-power speed range. This paper shows that defining the allowable machine design parameter plane using the characteristic current and the peak back-emf provides useful insights into how application requirements restrict the machine parameters. The parameter plane also shows the influence of changing the parameters on the machine's current rating and magnet losses. As an example of a practical application, the parameter plane is used to study the FreedomCAR traction motor drive requirements and the characteristics of five FSCW surface PM machine designs.W.L. Soong, P.B. Reddy, A.M. El-Refaie, T.M. Jahns and N. Ertugru

    Covariance of Antiproton Yield and Source Size in Nuclear Collisions

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    We confront for the first time the widely-held belief that combined event-by-event information from quark gluon plasma signals can reduce the ambiguity of the individual signals. We illustrate specifically how the measured antiproton yield combined with the information from pion-pion HBT correlations can be used to identify novel event classes.Comment: 8 pages, 5 figures, improved title, references and readability; results unchange

    Breast abscess due to Actinomyces europaeus

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    Actinomyces europaeus was first described in 1997 as a new species causing predominantly skin and soft-tissue infections. Mastitis due to A. europaeus is an unusual condition. This article reports a case of primary breast abscess caused by A. europaeus in a postmenopausal woma
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