519 research outputs found

    Heavy Quark Interactions in Finite Temperature QCD

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    We study the free energy of a heavy quark-antiquark pair in a thermal medium. We constuct a simple ansatz for the free energy for two quark flavors motivated by the Debye-H\"uckel theory of screening.Comment: 4 pages, 4 figures, contribution to the proceedings of the International Conference on Hard and Electromagnetic Probes of High Energy Nuclear Collisions, Ericeira, Portugal, Nov. 4-10, 200

    Sommerfeld's quantum condition of action and the spectra of Schwarzschild black hole

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    If the situation of quantum gravity nowadays is nearly the same as that of the quantum mechanics in it's early time of Bohr and Sommerfeld, then a first step study of the quantum gravity from Sommerfeld's quantum condition of action might be helpful. In this short paper the spectra of Schwarzschild black hole(SBH) in quasi-classical approach of quantum mechanics is given. We find the quantum of area, the quantum of entropy and the Hawking evaporation will cease as the black hole reaches its ground state.Comment: 7 pages, no figures, submitted to Classical and Quantum Gravit

    Digging the optimum pit: Antlions, spirals and spontaneous stratification

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    Most animal traps are constructed from self-secreted silk, so antlions are rare among trap builders because they use only materials found in the environment. We show how antlions exploit the properties of the substrate to produce very effective structures in the minimum amount of time. Our modelling demonstrates how antlions: (i) exploit self-stratification in granular media differentially to expose deleterious large grains at the bottom of the construction trench where they can be ejected preferentially, and (ii) minimize completion time by spiral rather than central digging. Both phenomena are confirmed by our experiments. Spiral digging saves time because it enables the antlion to eject material initially from the periphery of the pit where it is less likely to topple back into the centre. As a result, antlions can produce their pits—lined almost exclusively with small slippery grains to maximize powerful avalanches and hence prey capture—much more quickly than if they simply dig at the pit’s centre. Our demonstration, for the first time to our knowledge, of an animal using self-stratification in granular media exemplifies the sophistication of extended phenotypes even if they are only formed from material found in the animal’s environment

    Continuous positive airway pressure (CPAP) in nonapneic asthma: A clinical review of current evidence

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    © 2020 by Turkish Thoracic Society-. The use of continuous positive airway pressure (CPAP) in asthma has been a point of debate over the past several years. Various studies, including those on animals and humans have attempted to understand the role and pathophysiology of CPAP in patients with either well controlled or poorly controlled asthma. The aim of this manuscript is to review the currently available literature on the physiologic and clinical effects of CPAP in animal models of asthma and on humans with stable asthma

    High Levels of DEK Autoantibodies in Sera of Patients With Polyarticular Juvenile Idiopathic Arthritis and With Early Disease Flares Following Cessation of Anti–Tumor Necrosis Factor Therapy

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    © 2017 The Authors. Arthritis & Rheumatology published by Wiley Periodicals, Inc. on behalf of American College of Rheumatology. Objective: The nuclear oncoprotein DEK is an autoantigen associated with juvenile idiopathic arthritis (JIA), especially the oligoarticular subtype. DEK is a secreted chemotactic factor. Abundant levels of DEK and DEK autoantibodies are found in inflamed synovium in JIA. We undertook this study to further characterize the nature of DEK autoantibodies in screening serum samples from 2 different cohorts that consisted mostly of patients with JIA. Methods: DEK autoantibody levels were analyzed in sera from 33 JIA patients, 13 patients with other inflammatory conditions, and 11 healthy controls, as well as in 89 serum samples from JIA patients receiving anti–tumor necrosis factor (anti-TNF) therapy. Recombinant His-tagged full-length DEK protein (1–375 amino acids [aa]) and the 187–375-aa and 1–350-aa His-tagged DEK fragments made in a baculovirus system were used for enzyme-linked immunosorbent assay (ELISA) and immunoblotting. The C-terminal 25-aa fragment of DEK was expressed in a glutathione S-transferase–tagged vector. ELISA results were calculated as area under the curve by the trapezoidal rule. Results: DEK autoantibody levels were significantly higher in patients with polyarticular JIA than in those with oligoarticular JIA, and were higher in patients with polyarticular JIA who had more active disease after cessation of anti-TNF therapy. Immunoblotting against the C-terminal 25-aa fragment of DEK confirmed that this section of the DEK molecule is the most immunogenic domain. Conclusion: DEK autoantibody levels are higher in patients with polyarticular JIA than in those with oligoarticular JIA, and higher in patients who have disease flares after cessation of anti-TNF therapy. The C-terminal 25-aa fragment is the most immunogenic portion of DEK. These findings are significant with respect to the nature of DEK autoantibodies, their contribution to JIA pathogenesis, and their implications for JIA management

    Idelalisib and Rituximab in Relapsed Chronic Lymphocytic Leukemia

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    BackgroundPatients with relapsed chronic lymphocytic leukemia (CLL) who have clinically significant coexisting medical conditions are less able to undergo standard chemotherapy. Effective therapies with acceptable side-effect profiles are needed for this patient population. MethodsIn this multicenter, randomized, double-blind, placebo-controlled, phase 3 study, we assessed the efficacy and safety of idelalisib, an oral inhibitor of the delta isoform of phosphatidylinositol 3-kinase, in combination with rituximab versus rituximab plus placebo. We randomly assigned 220 patients with decreased renal function, previous therapy-induced myelosuppression, or major coexisting illnesses to receive rituximab and either idelalisib (at a dose of 150 mg) or placebo twice daily. The primary end point was progression-free survival. At the first prespecified interim analysis, the study was stopped early on the recommendation of the data and safety monitoring board owing to overwhelming efficacy. ResultsThe median progression-free survival was 5.5 months in the placebo group and was not reached in the idelalisib group (hazard ratio for progression or death in the idelalisib group, 0.15;

    Thermogravimetric and kinetic analysis of energy crop Jerusalem artichoke using the distributed activation energy model

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    Jerusalem artichoke has great potential as future feedstock for bioenergy production because of its high tuber yield (up to 90 t ha(-1)), appropriate biomass characteristics, low input demand, and positive environmental impact. The pyrolytic and kinetic characteristics of Jerusalem artichoke tubers were analyzed at heating rates of 5, 10, 20 and 30 A degrees C min(-1). TG and DTG curves in an inert (nitrogen) atmosphere suggested that there were three distinct stages of mass loss and the major loss occurs between about 190-380 A degrees C. Heating rate brought a lateral shift toward right in the temperature. And, it not only affects the temperature at which the highest mass loss rate reached, but also affect the maximum rate of mass loss. The distributed activation energy model (DAEM) was used to study the pyrolysis kinetics and provided reasonable fits to the experimental data. The activation energy (E) of tubers ranged from 146.40 to 232.45 kJ mol(-1), and the frequency factor (A) changed greatly corresponding to E values at different mass conversion.Jerusalem artichoke has great potential as future feedstock for bioenergy production because of its high tuber yield (up to 90 t ha(-1)), appropriate biomass characteristics, low input demand, and positive environmental impact. The pyrolytic and kinetic characteristics of Jerusalem artichoke tubers were analyzed at heating rates of 5, 10, 20 and 30 A degrees C min(-1). TG and DTG curves in an inert (nitrogen) atmosphere suggested that there were three distinct stages of mass loss and the major loss occurs between about 190-380 A degrees C. Heating rate brought a lateral shift toward right in the temperature. And, it not only affects the temperature at which the highest mass loss rate reached, but also affect the maximum rate of mass loss. The distributed activation energy model (DAEM) was used to study the pyrolysis kinetics and provided reasonable fits to the experimental data. The activation energy (E) of tubers ranged from 146.40 to 232.45 kJ mol(-1), and the frequency factor (A) changed greatly corresponding to E values at different mass conversion
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