399 research outputs found

    Properties of hadron screening masses at small baryonic density

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    The properties of hadron screening masses around the deconfinement phase transition at finite baryonic density can be studied by evaluating the Taylor coefficients with respect to the iso-scalar and iso-vector chemical potentials. We simulate 2-flavour lattice QCD with staggered fermions on a 12*12*24*6 lattice with ma = 0.05 and 0.10 and report investigations of nucleon, pseudo-scalar and vector mesons. We present new, strong evidence that in the confining phase, the screening masses at vanishing chemical potential have significant temperature dependence, but the effect of the iso-scalar chemical potential is very small. Above the critical temperature, the second derivative terms of mesons rapidly increase as contrasted to the case of baryon. We also study the responses of the screening masses to an iso-vector chemical potential and discuss some of the issues related to the properties of hadron masses at finite density.Comment: 7 pages with 5 figures; added two new references, the title of article and the section 'Concluding Remarks' are slightly change

    Role of rapid urease test and histopathology in the diagnosis of Helicobacter pylori infection in a developing country

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    BACKGROUND: The aim of this study was to determine the effect of commonly self-prescribed proton pump inhibitors (PPI) on the results of rapid urease test and histology for the diagnosis of H. pylori infection. METHODS: One hundred-nine consecutive patients with dyspeptic symptoms attending the endoscopy suite were enrolled in this study. Antrum biopsy specimens were collected at endoscopy for the rapid urease test (Pronto Dry, Medical Instrument Corp, France) and histopathology. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and like-hood ratio of a positive and negative of Pronto Dry test were compared against histology. The gold standard test for the diagnosis of H. pylori infection was histopathology. RESULTS: Sixty-one percent (66/109) patients were males with mean age of 43 ± 14.1 years and age range 17–80 years. Fifty-two percent (57/109) were not on any medications while 48% (52/109) used PPI before presentation to the outpatients. Pronto Dry was positive in 40% (44/109) and negative in 60% (65/109). Histopathology was positive for H. pylori in 57% (62/109) and negative in 43% (47/109). The sensitivity, specificity, PPV, NPV and like-hood ratio of a positive and negative Pronto Dry test with and without PPI were 43.3%, 86.4%, 81.3%, 3.18, 0.656 and 52.8% vs 71.9%, 80%, 82.1%, 69%, 3.59 and 0.35. CONCLUSION: This study shows that the sensitivity, specificity, NPV and PPV of rapid urease test was reduced in patients who are on PPI. The exclusive use of the rapid urease test for the diagnosis of Helicobacter pylori cannot be recommended in patients with prior PPI use

    Beam-target helicity asymmetry for γ→n→→π−p in the N*resonance region

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    We report the first beam-target double-polarization asymmetries in the Îł ĂŸ nĂ°pÞ → π− ĂŸ pĂ°pÞ reaction spanning the nucleon resonance region from invariant mass W ÂŒ 1500 to 2300 MeV. Circularly polarized photons and longitudinally polarized deuterons in solid hydrogen deuteride (HD) have been used with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The exclusive final state has been extracted using three very different analyses that show excellent agreement, and these have been used to deduce the E polarization observable for an effective neutron target. These results have been incorporated into new partial wave analyses and have led to significant revisions for several ÎłnN* resonance photocouplings

    Beam-Target Helicity Asymmetry for (gamma)over-right-arrow(n)over-right-arrow -\u3e pi(-)p in the N* Resonance Region

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    We report the first beam-target double-polarization asymmetries in the gamma+n(p)-\u3epi(-)+p(p) reaction spanning the nucleon resonance region from invariant mass W=1500 to 2300 MeV. Circularly polarized photons and longitudinally polarized deuterons in solid hydrogen deuteride (HD) have been used with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The exclusive final state has been extracted using three very different analyses that show excellent agreement, and these have been used to deduce the E polarization observable for an effective neutron target. These results have been incorporated into new partial wave analyses and have led to significant revisions for several gamma nN* resonance photocouplings

    Neuroimaging reveals functionally distinct neuronal networks associated with high-level alcohol consumption in two genetic rat models

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    Human imaging data suggest that the motivational processes associated with alcohol reward are reflected in the patterns of neural activation after alcohol or alcohol-related cues. In animal models of alcohol drinking, however, the changes in brain activation during voluntary alcohol ingestion are poorly known. In order to improve the translational utility of animal models, we examined alcohol-induced functional brain activation in Alko Alcohol (AA) and Marchigian-Sardinian alcohol-preferring (msP) rats that drink voluntarily high levels of alcohol, but exhibit widely different neurochemical and behavioral traits cosegregated with alcohol preference. Brain imaging was performed using manganese-enhanced MRI (MEMRI), which is based on accumulation of Mn2+ ions in activated neurons, allowing the identification of functional neuronal networks recruited during specific behaviors in awake animals during a subsequent imaging session under anesthesia. MEMRI was performed following 4 weeks of voluntary alcohol drinking, using water drinking as the control. Despite similar levels of alcohol drinking, strikingly different alcohol-induced neuronal activity patterns were observed in AA and msP rats. Overall, functional activation in the AA rats was more widespread, involving large cortical areas and subcortical structures, such as the bed nucleus of the stria terminalis, preoptic area, hypothalamus, periaqueductal grey, and substantia nigra. In the msP rats, however, alcohol-related activation was largely confined to prefrontal cortical regions and insular cortex, and olfactory areas. Overlapping areas of activation found in both rat lines included the nucleus accumbens, prelimbic, orbital, and insular cortex. In conclusion, our data reveal strikingly different brain circuits associated with alcohol drinking in two genetically different rat lines and suggest innately different motivational and behavioral processes driving alcohol drinking. These findings have important implications for the use of these lines in translational alcohol research.Peer reviewe

    Age-related macular degeneration in a randomized controlled trial of low-dose aspirin: Rationale and study design of the ASPREE-AMD study

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    Purpose: Although aspirin therapy is used widely in older adults for prevention of cardiovascular disease, its impact on the incidence, progression and severity of age-related macular degeneration (AMD) is uncertain. The effect of low-dose aspirin on the course of AMD will be evaluated in this clinical trial. Design: A sub-study of the ‘ASPirin in Reducing Events in the Elderly’ (ASPREE) trial, ASPREE-AMD is a 5-year follow-up double-blind, placebo-controlled, randomized trial of the effect of 100 mg daily aspirin on the course of AMD in 5000 subjects aged 70 years or older, with normal cognitive function and without cardiovascular disease at baseline. Non-mydriatic fundus photography will be performed at baseline, 3-year and 5-year follow-up to determine AMD status. Primary outcome measures: The incidence and progression of AMD. Exploratory analyses will determine whether aspirin affects the risk of retinal hemorrhage in late AMD, and whether other factors, such as genotype, systemic disease, inflammatory biomarkers, influence the effect of aspirin on AMD. Conclusion: The study findings will be of significant clinical and public interest due to a potential to identify a possible low cost therapy for preventing AMD worldwide and to determine risk/benefit balance of the aspirin usage by the AMD-affected elderly. The ASPREE-AMD study provides a unique opportunity to determine the effect of aspirin on AMD incidence and progression, by adding retinal imaging to an ongoing, large-scale primary prevention randomized clinical trial

    Factor H family proteins and human diseases

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    Complement is a major defense system of innate immunity and aimed to destroy microbes. One of the central complement regulators is factor H, which belongs to a protein family that includes CFHL1 and five factor H-related (CFHR) proteins. Recent evidence shows that factor H family proteins (factor H and CFHRs) are associated with diverse and severe human diseases and are also used by human pathogenic microbes for complement evasion. Therefore, dissecting the exact functions of the individual CFHR proteins will provide insights into the pathophysiology of such inflammatory and infectious diseases and will define the therapeutic potential of these proteins

    Heavy quarkonium: progress, puzzles, and opportunities

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    A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the BB-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair

    Impact of Chikungunya Virus Infection on Health Status and Quality of Life: A Retrospective Cohort Study

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    BACKGROUND:Persistent symptoms, mainly joint and muscular pain and depression, have been reported several months after Chikungunya virus (CHIKV) infection. Their frequency and their impact on quality of life have not been compared with those of an unexposed population. In the present study, we aimed to describe the frequency of prolonged clinical manifestations of CHIKV infection and to measure the impact on quality of life and health care consumption in comparison with that of an unexposed population, more than one year after infection. METHODOLOGY/PRINCIPAL FINDINGS:In a retrospective cohort study, 199 subjects who had serologically confirmed CHIKV infection (CHIK+) were compared with 199 sero-negative subjects (CHIK-) matched for age, gender and area of residence in La RĂ©union Island. Following an average time of 17 months from the acute phase of infection, participants were interviewed by telephone about current symptoms, medical consumption during the last 12 months and quality of life assessed by the 12-items Short-Form Health Survey (SF-12) scale. At the time of study, 112 (56%) CHIK+ persons reported they were fully recovered. CHIK+ complained more frequently than CHIK- of arthralgia (relative risk = 1.9; 95% confidence interval: 1.6-2.2), myalgia (1.9; 1.5-2.3), fatigue (2.3; 1.8-3), depression (2.5; 1.5-4.1) and hair loss (3.8; 1.9-7.6). There was no significant difference between CHIK+ and CHIK- subjects regarding medical consumption in the past year. The mean (SD) score of the SF-12 Physical Component Summary was 46.4 (10.8) in CHIK+ versus 49.1 (9.3) in CHIK- (p = 0.04). There was no significant difference between the two groups for the Mental Component Summary. CONCLUSIONS/SIGNIFICANCE:More than one year following the acute phase of infection, CHIK+ subjects reported more disabilities than those who were CHIK-. These persistent disabilities, however, have no significant influence on medical consumption, and the impact on quality of life is moderate
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