155 research outputs found

    Investigation of antioxidant effects of rosmarinic acid on liver, lung and kidney in rats: a biochemical and histopathological study

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    Background: The aim of the study was to investigate the protective effects of rosmarinic acid in rats exposed to hepatic ischaemia/reperfusion (I/R) injury. Materials and methods: Thirty-two rats were randomly classified into four groups of 8 rats each: laparotomy without medication, rosmarinic acid (dose of 50 mg/kg via oral gavage) followed by laparotomy, laparotomy followed by hepatic I/R, and hepatic I/R with rosmarinic acid. Serum aspartate aminotransferase, alaninÄ™ aminotransferase, and malondialdehyde levels and total oxidant activity and total antioxidant capacity levels of the liver, lung, and kidney were assessed. The histopathologic assessment was also performed. Results: Rosmarinic acid significantly reduced liver function test parameters and decreased oxidative stress and abnormal histopathologic findings in the liver. The oxidative stress in the lung significantly increased in the I/R group but significantly decreased in the I/R + rosmarinic acid group due to the addition of rosmarinic acid. Rosmarinic acid led to no reduction in oxidative stress in kidney following hepatic I/R injury. There were no statistically significant differences among the groups regarding histopathologic changes in kidney and lung sections. Conclusions: Rosmarinic acid has antioxidant properties and is an effective hepatoprotective agent. However, although rosmarinic acid provides useful effects in the lung by increasing antioxidant capacity and reducing oxidative stress after I/R injury, it does not ameliorate histopathologic changes. These findings suggest that rosmarinic acid is likely to provide favourable outcomes in the treatment of hepatic I/R injury

    Multidrug resistant Acinetobacter baumannii: a descriptive study in a city hospital

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    <p>Abstract</p> <p>Background</p> <p>Multidrug resistant <it>Acinetobacter baumannii</it>, (MRAB) is an important cause of hospital acquired infection. The purpose of this study is to determine the risk factors for MRAB in a city hospital patient population.</p> <p>Methods</p> <p>This study is a retrospective review of a city hospital epidemiology data base and includes 247 isolates of Acinetobacter baumannii (AB) from 164 patients. Multidrug resistant <it>Acinetobacter baumannii </it>was defined as resistance to more than three classes of antibiotics. Using the non-MRAB isolates as the control group, the risk factors for the acquisition of MRAB were determined.</p> <p>Results</p> <p>Of the 247 AB isolates 72% (177) were multidrug resistant. Fifty-eight percent (143/247) of isolates were highly resistant (resistant to imipenem, amikacin, and ampicillin-sulbactam). Of the 37 patients who died with Acinetobacter colonization/infection, 32 (86%) patients had the organism recovered from the respiratory tract. The factors which were found to be significantly associated (p ≤ 0.05) with multidrug resistance include the recovery of AB from multiple sites, mechanical ventilation, previous antibiotic exposure, and the presence of neurologic impairment. Multidrug resistant Acinetobacter was associated with significant mortality when compared with sensitive strains (p ≤ 0.01). When surgical patients (N = 75) were considered separately, mechanical ventilation and multiple isolates remained the factors significantly associated with the development of multidrug resistant Acinetobacter. Among surgical patients 46/75 (61%) grew a multidrug resistant strain of AB and 37/75 (40%) were resistant to all commonly used antibiotics including aminoglycosides, cephalosporins, carbepenems, extended spectrum penicillins, and quinolones. Thirty-five percent of the surgical patients had AB cultured from multiple sites and 57% of the Acinetobacter isolates were associated with a co-infecting organism, usually a Staphylococcus or Pseudomonas. As in medical patients, the isolation of Acinetobacter from multiple sites and the need for mechanical ventilation were significantly associated with the development of MRAB.</p> <p>Conclusions</p> <p>The factors significantly associated with MRAB in both the general patient population and surgical patients were mechanical ventilation and the recovery of Acinetobacter from multiple anatomic sites. Previous antibiotic use and neurologic impairment were significant factors in medical patients. Colonization or infection with MRAB is associated with increased mortality.</p

    TES-Based Light Detectors for the CRESST Direct Dark Matter Search

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    The CRESST experiment uses cryogenic detectors based on transition-edge sensors to search for dark matter interactions. Each detector module consists of a scintillating CaWO₄ crystal and a silicon-on-sapphire (SOS) light detector which operate in coincidence (phonon-light technique). The 40-mm-diameter SOS disks (2 g mass) used in the data taking campaign of CRESST-II Phase 2 (2014–2016) reached absolute baseline resolutions of σ = 4–7 eV. This is the best performance reported for cryogenic light detectors of this size. Newly developed silicon beaker light detectors (4 cm height, 4 cm diameter, 6 g mass), which cover a large fraction of the target crystal surface, have achieved a baseline resolution of σ = 5.8 eV. First results of further improved light detectors developed for the ongoing low-threshold CRESST-III experiment are presented. Keywords: Transition-edge sensor; Cryogenic light detector; Direct dark matter searc

    Volume reduction of water samples to increase sensitivity for radioassay of lead contamination

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    The World Health Organisation (WHO) presents an upper limit for lead in drinking water of 10 parts per billion ppb. Typically, to reach this level of sensitivity, expensive metrology is required. To increase the sensitivity range of low-cost devices, this paper explores the prospects of using a volume reduction technique of a boiled water sample doped with Lead-210 (210 Pb), as a means to increase the solute’s concentration. 210Pb is a radioactive lead isotope and its concentration in a water sample can be measured with e.g. High Purity Germanium (HPGe) detectors at the Boulby Underground Germanium Suite. Concentrations close to the WHO limit have not been examined. This paper presents a measurement of the volume reduction technique retaining 99±(9)% of 210Pb starting from a concentration of 1.9×10−6 ppb before reduction and resulting in 2.63×10−4 ppb after reduction. This work also applies the volume reduction technique to London tap water and reports the radioassay results from gamma counting in HPGe detectors. Among other radio-isotopes, 40K, 210Pb, 131I and 177Lu were identified at measured concentrations of 2.83×103 ppb, 2.55×10−7 ppb, 5.06×10−10 ppb and 5.84×10−10 ppb in the London tap water sample. This technique retained 90±50% of 40K. Stable lead was inferred from the same water sample at a measured concentration of 0.012 ppb, prior to reduction

    Sensitivity projections for a dual-phase argon TPC optimized for light dark matter searches through the ionization channel

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    Characterization of germanium detectors for the first underground laboratory in Mexico

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    This article reports the characterization of two High Purity Germanium detectors performed by extracting and comparing their efficiencies using experimental data and Monte Carlo simulations. The efficiencies were calculated for pointlike γ-ray sources as well as for extended calibration sources. Characteristics of the detectors such as energy linearity, energy resolution and full energy peak efficiencies are reported from measurements performed on surface laboratories. The detectors will be deployed in a γ-ray assay facility that will be located in the first underground laboratory in Mexico, Laboratorio Subterr&apos;aneo de Mineral del Chico (LABChico), in the Comarca Minera UNESCO Global Geopark [1]

    Precision Measurement of the Boron to Carbon Flux Ratio in Cosmic Rays from 1.9 GV to 2.6 TV with the Alpha Magnetic Spectrometer on the International Space Station

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    Knowledge of the rigidity dependence of the boron to carbon flux ratio (B/C) is important in understanding the propagation of cosmic rays. The precise measurement of the B/C ratio from 1.9 GV to 2.6 TV, based on 2.3 million boron and 8.3 million carbon nuclei collected by AMS during the first 5 years of operation, is presented. The detailed variation with rigidity of the B/C spectral index is reported for the first time. The B/C ratio does not show any significant structures in contrast to many cosmic ray models that require such structures at high rigidities. Remarkably, above 65 GV, the B/C ratio is well described by a single power law R[superscript Δ] with index Δ=-0.333±0.014(fit)±0.005(syst), in good agreement with the Kolmogorov theory of turbulence which predicts Δ=-1/3 asymptotically.National Science Foundation (U.S.) (Grants 1455202 and 1551980)Wyle Research (Firm) (Grant 2014/T72497)United States. National Aeronautics and Space Administration (NASA Earth and Space Science Fellowship Grant HELIO15F-0005

    Antiproton Flux, Antiproton-to-Proton Flux Ratio, and Properties of Elementary Particle Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station

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    International audienceA precision measurement by AMS of the antiproton flux and the antiproton-to-proton flux ratio inprimary cosmic rays in the absolute rigidity range from 1 to 450 GV is presented based on 3.49 × 105antiproton events and 2.42 × 109 proton events. The fluxes and flux ratios of charged elementary particlesin cosmic rays are also presented. In the absolute rigidity range ∼60 to ∼500 GV, the antiproton ¯p, protonp, and positron eþ fluxes are found to have nearly identical rigidity dependence and the electron e− fluxexhibits a different rigidity dependence. Below 60 GV, the ( ¯ p=p), ( ¯ p=eþ), and (p=eþ) flux ratios eachreaches a maximum. From ∼60 to ∼500 GV, the ( ¯ p=p), ( ¯ p=eþ), and (p=eþ) flux ratios show no rigiditydependence. These are new observations of the properties of elementary particles in the cosmos
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