18 research outputs found

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Cardiac dysfunction in cirrhosis is not associated with the severity of liver disease

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    Background: Cirrhotic cardiomiopathy is described as the presence of cardiac dysfunction in cirrhotic patients. The aim of the study was to investigate factors associated with cardiac dysfunction in cirrhotic patients. Patients and methods: Seventy-four cirrhotic patients and twenty-six controls performed a conventional echocardiography and Tissue Doppler Imaging (TDI) for systolic and diastolic function. Results were analyzed by using the Guidelines of American Society of Echocardiography. Results: In patients with cirrhosis, left ventricular end-diastolic diameter was increased (p<0.001), peak systolic velocities were decreased (11.3 +/- 2.7 vs 13.9 +/- 1.4 cm/s; p<0.001) and left atrial volumes were increased (32.7 +/- 8.3 vs 24 +/- 8.5 ml, p<0.001) as well as cardiac mass (90.6 +/- 23 vs 70.5 +/- 22 g/m(2), p<0.001). Forty-seven cirrhotic patients (64%) showed diastolic dysfunction at rest: grade I in 37 and grade II in 10 patients. Systolic and/or diastolic dysfunction were not influenced by a more severe liver impairment. Diastolic dysfunction was more prevalent in patients with ascites vs those without (77% vs 56%; p=0.04). Conclusion: A mild diastolic dysfunction at rest is frequent in cirrhotic patients but cardiac load conditions are confounding factors in this diagnosis. We did not identify an association between severity of liver disease and cardiac dysfunction. (C) 2012 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved

    Does cirrhotic cardiomyopathy exist? 50 years of uncertainty

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    Subtle abnormalities of cardiac structure or function are often identified in patients with liver cirrhosis and have been termed cirrhotic cardiomyopathy. However, in the absence of a precise definition, its diagnosis remains a challenge. Cardiac dysfunction in patients with cirrhosis can often be attributed to concomitant diseases such as hypertension, ischaemic heart disease or excess alcohol consumption in many patients. Further research is required to identify the existence, origin and importance of abnormal cardiac function due specifically to liver disease. Cardiac dysfunction may be masked by treatments given to cirrhotic patients, such as mineral-corticoid receptor antagonists, or by co-existing conditions, such as anaemia. New imaging tests or plasma biomarkers might be able to detect abnormal cardiac function at an early stage of its development
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