369 research outputs found

    Three-loop matching coefficients for hot QCD: Reduction and gauge independence

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    We perform an integral reduction for the 3-loop effective gauge coupling and screening mass of QCD at high temperatures, defined as matching coefficients appearing in the dimensionally reduced effective field theory (EQCD). Expressing both parameters in terms of a set master (sum-) integrals, we show explicit gauge parameter independence. The lack of suitable methods for solving the comparatively large number of master integrals forbids the complete evaluation at the moment. Taking one generic class of masters as an example, we highlight the calculational techniques involved. The full result would allow to improve on one of the classic probes for the convergence of the weak-coupling expansion at high temperatures, namely the comparison of full and effective theory determinations of the spatial string tension. Furthermore, the full result would also allow to determine one new contribution of order O(g**7) to the pressure of hot QCD.Comment: 19 pages, 2 figures. v2: new Section 6 discussing applications, to match journal versio

    Insulin and GH Signaling in Human Skeletal Muscle In Vivo following Exogenous GH Exposure: Impact of an Oral Glucose Load

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    GH induces acute insulin resistance in skeletal muscle in vivo, which in rodent models has been attributed to crosstalk between GH and insulin signaling pathways. Our objective was to characterize time course changes in signaling pathways for GH and insulin in human skeletal muscle in vivo following GH exposure in the presence and absence of an oral glucose load.Eight young men were studied in a single-blinded randomized crossover design on 3 occasions: 1) after an intravenous GH bolus 2) after an intravenous GH bolus plus an oral glucose load (OGTT), and 3) after intravenous saline plus OGTT. Muscle biopsies were taken at t = 0, 30, 60, and 120. Blood was sampled at frequent intervals for assessment of GH, insulin, glucose, and free fatty acids (FFA).GH increased AUC(glucose) after an OGTT (p<0.05) without significant changes in serum insulin levels. GH induced phosphorylation of STAT5 independently of the OGTT. Conversely, the OGTT induced acute phosphorylation of the insulin signaling proteins Akt (ser(473) and thr(308)), and AS160.The combination of OGTT and GH suppressed Akt activation, whereas the downstream expression of AS160 was amplified by GH. WE CONCLUDED THE FOLLOWING: 1) A physiological GH bolus activates STAT5 signaling pathways in skeletal muscle irrespective of ambient glucose and insulin levels 2) Insulin resistance induced by GH occurs without a distinct suppression of insulin signaling proteins 3) The accentuation of the glucose-stimulated activation of AS 160 by GH does however indicate a potential crosstalk between insulin and GH.ClinicalTrials.gov NCT00477997

    Can We Really Prevent Suicide?

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    Every year, suicide is among the top 20 leading causes of death globally for all ages. Unfortunately, suicide is difficult to prevent, in large part because the prevalence of risk factors is high among the general population. In this review, clinical and psychological risk factors are examined and methods for suicide prevention are discussed. Prevention strategies found to be effective in suicide prevention include means restriction, responsible media coverage, and general public education, as well identification methods such as screening, gatekeeper training, and primary care physician education. Although the treatment for preventing suicide is difficult, follow-up that includes pharmacotherapy, psychotherapy, or both may be useful. However, prevention methods cannot be restricted to the individual. Community, social, and policy interventions will also be essentia

    Coupling Classical and Quantum Variables using Continuous Quantum Measurement Theory

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    We propose a system of equations to describe the interaction of a quasiclassical variable XX with a set of quantum variables xx that goes beyond the usual mean field approximation. The idea is to regard the quantum system as continuously and imprecisely measured by the classical system. The effective equations of motion for the classical system therefore consist of treating the quantum variable xx as a stochastic c-number \x (t) the probability distibution for which is given by the theory of continuous quantum measurements. The resulting theory is similar to the usual mean field equations (in which xx is replaced by its quantum expectation value) but with two differences: a noise term, and more importantly, the state of the quantum subsystem evolves according to the stochastic non-linear Schrodinger equation of a continuously measured system. In the case in which the quantum system starts out in a superposition of well-separated localized states, the classical system goes into a statistical mixture of trajectories, one trajectory for each individual localized state.Comment: 11 pages, plain Tex (with revised settings for \vsize and \voffset to accommodate US paper sizes

    Long-term clearance from small airways in subjects with ciliary dysfunction

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    The objective of this study was to investigate if long-term clearance from small airways is dependent on normal ciliary function. Six young adults with primary ciliary dyskinesia (PCD) inhaled (111 )Indium labelled Teflon particles of 4.2 μm geometric and 6.2 μm aerodynamic diameter with an extremely slow inhalation flow, 0.05 L/s. The inhalation method deposits particles mainly in the small conducting airways. Lung retention was measured immediately after inhalation and at four occasions up to 21 days after inhalation. Results were compared with data from ten healthy controls. For additional comparison three of the PCD subjects also inhaled the test particles with normal inhalation flow, 0.5 L/s, providing a more central deposition. The lung retention at 24 h in % of lung deposition (Ret(24)) was higher (p < 0.001) in the PCD subjects, 79 % (95% Confidence Interval, 67.6;90.6), compared to 49 % (42.3;55.5) in the healthy controls. There was a significant clearance after 24 h both in the PCD subjects and in the healthy controls with equivalent clearance. The mean Ret(24 )with slow inhalation flow was 73.9 ± 1.9 % compared to 68.9 ± 7.5 % with normal inhalation flow in the three PCD subjects exposed twice. During day 7–21 the three PCD subjects exposed twice cleared 9 % with normal flow, probably representing predominantly alveolar clearance, compared to 19 % with slow inhalation flow, probably representing mainly small airway clearance. This study shows that despite ciliary dysfunction, clearance continues in the small airways beyond 24 h. There are apparently additional clearance mechanisms present in the small airways

    Towards enhancing national capacity for evidence informed policy and practice in falls management: a role for a "Translation Task Group"?

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    There has been a growing interest over recent years, both within Australia and overseas, in enhancing the translation of research into policy and practice. As one mechanism to improve the dissemination and uptake of falls research into policy and practice and to foster the development of policy-appropriate research, a Falls Translation Task Group has formed to facilitate linkage and exchange. There has been a growing interest over recent years, both within Australia and overseas, in enhancing the translation of research into policy and practice. As one mechanism to improve the dissemination and uptake of falls research into policy and practice and to foster the development of policy-appropriate research, a Falls Translation Task Group was formed as part of an NHMRC Population Health Capacity Building grant. This paper reports on the group\u27s first initiative to address issues around the research to policy and practice interface, and identifies a continuing role for such a group. MethodA one day forum brought together falls researchers and decision-makers from across the nation to facilitate linkage and exchange. Observations of the day\u27s proceedings were made by the authors. Participants were asked to complete a questionnaire at the commencement of the forum (to ascertain expectations) and at its completion (to evaluate the event). Observer notes and the questionnaire responses form the basis of analysis. Results: Both researchers and decision-makers have a desire to bridge the gap between research and policy and practice. Significant barriers to research uptake were highlighted and included both health system barriers (for example, a lack of financial and human resources) as well as evidence barriers (such as insufficient economic data and implementation research). Solutions to some of these barriers included the identification of clinical champions within the health sector to enhance evidence uptake, and the sourcing of alternative funding to support implementation research and encourage partnerships between researchers, decision-makers and other stakeholders. Conclusion: Participants sought opportunities for ongoing networking and collaboration. Two activities have been identified as priorities: establishing a policy-sensitive research agenda and partnering researchers and decision-makers in the process; and establishing a National Translation Task Group with a broad membership

    Self-perceived psychological stress and ischemic stroke: a case-control study

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    <p>Abstract</p> <p>Background</p> <p>A growing body of evidence suggests that psychological stress contributes to coronary artery disease. However, associations between stress and stroke are less clear. In this study, we investigated the possible association between ischemic stroke and self-perceived psychological stress, as measured by a single-item questionnaire, previously reported to be associated with myocardial infarction.</p> <p>Methods</p> <p>In the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS), 600 consecutive patients with acute ischemic stroke (aged 18 to 69 years) and 600 age-matched and sex-matched population controls were recruited. Ischemic stroke subtype was determined according to Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria. Self-perceived psychological stress preceding stroke was assessed retrospectively using a single-item questionnaire.</p> <p>Results</p> <p>Permanent self-perceived psychological stress during the last year or longer was independently associated with overall ischemic stroke (multivariate adjusted odds ratio (OR) 3.49, 95% confidence interval (CI) 2.06 to 5.93). Analyses by stroke subtype showed that this association was present for large vessel disease (OR 3.91, 95% CI 1.58 to 9.67), small vessel disease (OR 3.20, 95% CI 1.64 to 6.24), and cryptogenic stroke (OR 4.03, 95% CI 2.34 to 6.95), but not for cardioembolic stroke (OR 1.48, 95% CI 0.64 to 3.39).</p> <p>Conclusion</p> <p>In this case-control study, we found an independent association between self-perceived psychological stress and ischemic stroke. A novel finding was that this association differed by ischemic stroke subtype. Our results emphasize the need for further prospective studies addressing the potential role for psychological stress as a risk factor for ischemic stroke. In such studies ischemic stroke subtypes should be taken into consideration.</p

    Increased expression of vascular endothelin type B and angiotensin type 1 receptors in patients with ischemic heart disease

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    <p>Abstract</p> <p>Background</p> <p>Endothelin-1 and angiotensin II are strong vasoconstrictors. Patients with ischemic heart disease have elevated plasma levels of endothelin-1 and angiotensin II and show increased vascular tone. The aim of the present study was to examine the endothelin and angiotensin II receptor expression in subcutaneous arteries from patients with different degrees of ischemic heart disease.</p> <p>Methods</p> <p>Subcutaneous arteries were obtained, by biopsy from the abdomen, from patients undergoing coronary artery bypass graft (CABG) surgery because of ischemic heart disease (n = 15), patients with angina pectoris without established myocardial infarction (n = 15) and matched cardiovascular healthy controls (n = 15). Endothelin type A (ET<sub>A</sub>) and type B (ET<sub>B</sub>), and angiotensin type 1 (AT<sub>1</sub>) and type 2 (AT<sub>2</sub>) receptors expression and function were examined using immunohistochemistry, Western blot and <it>in vitro </it>pharmacology.</p> <p>Results</p> <p>ET<sub>A </sub>and, to a lesser extent, ET<sub>B </sub>receptor staining was observed in the healthy vascular smooth muscle cells. The level of ET<sub>B </sub>receptor expression was higher in patients undergoing CABG surgery (250% ± 23%; P < 0.05) and in the patients with angina pectoris (199% ± 6%; P < 0.05), than in the healthy controls (100% ± 28%). The data was confirmed by Western blotting. Arteries from CABG patients showed increased vasoconstriction upon administration of the selective ET<sub>B </sub>receptor agonist sarafotoxin S6c, compared to healthy controls (P < 0.05). No such difference was found for the ET<sub>A </sub>receptors. AT<sub>1 </sub>and, to a lesser extent, AT<sub>2 </sub>receptor immunostaining was seen in the vascular smooth muscle cells. The level of AT<sub>1 </sub>receptor expression was higher in both the angina pectoris (128% ± 25%; P < 0.05) and in the CABG patients (203% ± 41%; P < 0.05), as compared to the healthy controls (100% ± 25%). The increased AT<sub>1 </sub>receptor expression was confirmed by Western blotting. Myograph experiment did however not show any change in vasoconstriction to angiotensin II in CABG patients compared to healthy controls (P = n.s).</p> <p>Conclusion</p> <p>The results demonstrate, for the first time, upregulation of ET<sub>B </sub>and AT<sub>1 </sub>receptors in vascular smooth muscle cells in ischemic heart disease. These receptors may play a role in the pathophysiology of ischemic heart disease and could provide important targets for pharmaceutical interventions.</p
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