2,556 research outputs found

    Quantum mechanical virial theorem in systems with translational and rotational symmetry

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    Generalized virial theorem for quantum mechanical nonrelativistic and relativistic systems with translational and rotational symmetry is derived in the form of the commutator between the generator of dilations G and the Hamiltonian H. If the conditions of translational and rotational symmetry together with the additional conditions of the theorem are satisfied, the matrix elements of the commutator [G, H] are equal to zero on the subspace of the Hilbert space. Normalized simultaneous eigenvectors of the particular set of commuting operators which contains H, J^{2}, J_{z} and additional operators form an orthonormal basis in this subspace. It is expected that the theorem is relevant for a large number of quantum mechanical N-particle systems with translational and rotational symmetry.Comment: 24 pages, accepted for publication in International Journal of Theoretical Physic

    Markedly lower follow-up rate after liver biopsy in patients with non-alcoholic fatty liver diseases than those with viral hepatitis in Japan

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    <p>Abstract</p> <p>Background</p> <p>Patients with non-alcoholic fatty liver diseases (NAFLD) are recommended to have periodic follow-up exams because these patients are at increased risk of the presence of non-alcoholic steatohepatitis (NASH), which can lead to cirrhosis or hepatocellular carcinoma. We investigated the follow-up status of NAFLD patients after a liver biopsy examination.</p> <p>Methods</p> <p>We compared the follow-up rates of NAFLD patients who had received an ultrasonography-guided liver biopsy and patients who had received a liver biopsy for chronic viral hepatitis (hepatitis B or C).</p> <p>Results</p> <p>The 1- and 3-year follow-up rates after the liver biopsy were 92.7% and 88.3% for patients with chronic HBV infection, and 93.4% and 88.2% for patients with chronic HCV infection, respectively. In contrast, the follow-up rates for NAFLD patients were 77.6% and 49.9%, respectively, which were significantly lower than those of patients with chronic viral hepatitis (<it>p </it>< 0.0001). Among NAFLD patients, the respective 1- and 3-year follow-up rates were 73.0% and 44.6% for patients with simple steatosis and 80.0% and 52.4% for patients with NASH based on a pathologic diagnosis, without significant difference between these two subgroups (<it>p </it>= 0.5202).</p> <p>Conclusions</p> <p>The outpatient-based follow-up rate after a liver biopsy was significantly lower in NAFLD patients compared to patients with chronic viral hepatitis, regardless of the presence of NASH. It is important to determine how to maintain regular hospital visits for NAFLD patients, preventing patient attrition.</p

    Transition Temperature of a Uniform Imperfect Bose Gas

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    We calculate the transition temperature of a uniform dilute Bose gas with repulsive interactions, using a known virial expansion of the equation of state. We find that the transition temperature is higher than that of an ideal gas, with a fractional increase K_0(na^3)^{1/6}, where n is the density and a is the S-wave scattering length, and K_0 is a constant given in the paper. This disagrees with all existing results, analytical or numerical. It agrees exactly in magnitude with a result due to Toyoda, but has the opposite sign.Comment: Email correspondence to [email protected] ; 2 pages using REVTe

    Influence of steps on the tilting and adsorption dynamics of ordered Pn films on vicinal Ag(111) surfaces

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    Here we present a structural study of pentacene (Pn) thin films on vicinal Ag(111) surfaces by He atom diffraction measurements and density functional theory (DFT) calculations supplemented with van der Waals (vdW) interactions. Our He atom diffraction results suggest initial adsorption at the step edges evidenced by initial slow specular reflection intensity decay rate as a function of Pn deposition time. In parallel with the experimental findings, our DFT+vdW calculations predict the step edges as the most stable adsorption site on the surface. An isolated molecule adsorbs as tilted on the step edge with a binding energy of 1.4 eV. In addition, a complete monolayer (ML) with pentacenes flat on the terraces and tilted only at the step edges is found to be more stable than one with all lying flat or tilted molecules, which in turn influences multilayers. Hence our results suggest that step edges can trap Pn molecules and act as nucleation sites for the growth of ordered thin films with a crystal structure similar to that of bulk Pn.Comment: 4 pages, 4 figures, 1 tabl

    On-Orbit Results of Photoelectron Current Measurement System in Low Earth Orbit on HORYU-IV Satellite

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    On-orbit photoelectron current experiment is one of the missions carried out with the less resource available from a HORYU-IV satellite, for measuring the current from metallic and insulator surfaces from air mass zero (AMO) spectrum. This is with the view to determined photoelectron potential of materials widely used in spacecraft in space. HORYU-IV also known as Arc Event Generator and Investigator satellite (AEGIS) is among HORYU satellite series of Kyushu Institute of Technology, which was launched on February 17, 2016 as a piggy-back on-board H-IIA rocket. The measurement system consists of current-voltage amplifier circuits for Au, Kapton and Black Kapton samples with varying gains and other discrete components. We present the analysis of the telemetry data obtained after the launch; validate the effectiveness of the design and verification processes. The results show that the current measured from Black kapton sample surface had 1.80 nA and 2.70 nA, corresponds to 69.1ᵒ and 75.1ᵒ minimum and maximum elevation angles respectively. This paper described the on-orbit result of PEC and its verification through ground tests

    Solid Phase Extraction of Thorium and Uranium and their Separation from Lanthanides using Humic Acid Silica Gel as a Low-Cost Adsorbent

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    Solid phase extraction and separation of thorium (Th), uranium (U) and lanthanides were achieved using a humic acid-modified silica gel (Si-HA). Adsorption capacity, effect of contact time, pH, and adsorbent dose were examined at room temperature. The maximum adsorbent capacities (pH = 3) for Th and U were 28.0 and 31.3 mg g-1, respectively. The isotherm parameters denoted that the adsorption was favorable and optimum conditions were attained within 90 min. The kinetic data conformed well to pseudo-second order and intra-particle diffusion models. The distribution coefficients of U, Th and lanthanides in EDTA, citric acid and nitric acid media signify the possible separation of each element from the others. The salinity did not significantly affect the ability of Si-HA to extract Th and U. The adsorbent stability and reusability were also assessed through four-adsorption-desorption cycles. The simplicity of the proposed separation method along with the stability of the adsorbent and high regeneration efficiency under acidic conditions demonstrated the merit of using Si-HA as a low-cost adsorbent

    Rationale and design of the AXIOMATIC-SSP phase II trial: Antithrombotic treatment with factor XIa inhibition to Optimize Management of Acute Thromboembolic events for Secondary Stroke Prevention

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    MRI; Milvexian; Stroke preventionResonancia magnética; Milvexian; Prevención de ictusRessonància magnètica; Milvexian; Prevenció d'ictusBackground Individuals with ischemic stroke or transient ischemic attack (TIA) have a high early risk of ischemic stroke despite dual antiplatelet therapy. The risk of ischemic stroke, and associated disability, represents a significant unmet clinical need. Genetic variants resulting in reduced factor XI levels are associated with reduced risk for ischemic stroke but are not associated with increased intracranial bleeding. Milvexian is an oral small-molecule inhibitor of FXIa that binds activated factor XI with high affinity and selectivity and may reduce the risk of stroke when added to antiplatelet drugs without significant bleeding. We aimed to evaluate the dose-response relationship of milvexian in participants treated with dual antiplatelets. Methods We began a phase II, double-blinded, randomized, placebo-controlled trial at 367 sites in 2019. Participants (N = 2366) with ischemic stroke (National Institutes of Health Stroke Scale score ≤7) or high-risk TIA (ABCD2 score ≥6) were randomized to 1 of 5 doses of milvexian or placebo for 90 days. Participants also received clopidogrel 75 mg daily for the first 21 days and aspirin 100 mg for 90 days. The efficacy endpoint was the composite of ischemic stroke or incident infarct on magnetic resonance imaging. Major bleeding, defined as type 3 or 5 bleeding according to the Bleeding Academic Research Consortium, was the safety endpoint. Participant follow-up will end in 2022. Conclusion The AXIOMATIC-SSP trial will evaluate the dose-response of milvexian for ischemic stroke occurrence in participants with ischemic stroke or TIA.This study is sponsored by Bristol Myers Squibb and Janssen Research & Development, LLC

    Oidium neolycopersici: Intra-specific variability inferred from AFLP analysis and relationship with closely related powdery mildew fungi infecting various plant species

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    Previous works indicated a considerable variation in the pathogenicity, virulence, and host range of Oidium neolycopersici isolates causing tomato powdery mildew epidemics in many parts of the world. In this study, rDNA internal transcribed spacer (ITS) sequences, and amplified fragment length polymorphism (AFLP) patterns were analyzed in 17 O. neolycopersici samples collected in Europe, North America, and Japan, including those which overcame some of the tomato major resistance genes. The ITS sequences were identical in all 10 samples tested and were also identical to ITS sequences of eight previously studied O. neolycopersici specimens. The AFLP analysis revealed a high genetic diversity in O. neolycopersici and indicated that all 17 samples represented different genotypes. This might suggest the existence of either a yet unrevealed sexual reproduction or other genetic mechanisms that maintain a high genetic variability in O. neolycopersici. No clear correlation was found between the virulence and the AFLP patterns of the O. neolycopersici isolates studied. The relationship between O. neolycopersici and powdery mildew anamorphs infecting Aquilegia vulgaris, Chelidonium majus, Passiflora caerulea, and Sedum alboroseum was also investigated. These anamorphs are morphologically indistinguishable from and phylogenetically closely related to O. neolycopersici. The cross-inoculation tests and the analyses of ITS sequences and AFLP patterns jointly indicated that the powdery mildew anamorphs collected from the above mentioned plant species all represent distinct, but closely related species according to the phylogenetic species recognition. All these species were pathogenic only to their original host plant species, except O. neolycopersici which infected S. alboroseum, tobacco, petunia, and Arabidopsis thaliana, in addition to tomato, in cross-inoculation tests. This is the first genome-wide study that investigates the relationships among powdery mildews that are closely related based on ITS sequences and morphology. The results indicate that morphologically indistinguishable powdery mildews that differed in only one to five single nucleotide positions in their ITS region are to be considered as different taxa with distinct host ranges
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