52,240 research outputs found

    The Spin--Symmetry of the Quark Model

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    Corrections to the exact heavy--quark symmetry results are expected to follow the 1/mQ1/m_{Q} mass effect of the heavy--quark. We show, by an explicit calculation, that there is something other than the mass effect that suppresses the breaking of the spin symmetry

    Association of serum-soluble heat shock protein 60 with carotid atherosclerosis: clinical significance determined in a follow-up study

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    BACKGROUND AND PURPOSE: Previous work has shown that soluble heat shock protein 60 (HSP60; sHSP60), present in circulating blood, is associated with carotid atherosclerosis. In the current evaluation, we tested the hypothesis that sHSP60 levels are associated with the progression of carotid arteriosclerosis, prospectively. METHODS: The association of sHSP60 with early atherogenesis (5-year development and progression of nonstenotic carotid plaques) was investigated as part of the population-based prospective Bruneck Study. The current study focused on the follow-up period between 1995 and 2000 and, thus, included 684 subjects. RESULTS: sHSP60 levels measured in 1995 and 2000 were highly correlated (r=0.40; P<0.001), indicating consistency over a 5-year period. Circulating HSP60 levels were significantly correlated with antilipopolysaccharide and anti-HSP60 antibodies. It was also elevated in subjects with chronic infection (top quintile group of HSP60, among subjects with and without chronic infection: 23.8% versus 17.0%; P=0.003 after adjustment for age and sex). HSP60 levels were significantly associated with early atherogenesis, both in the entire population (multivariate odds ratio, for a comparison between quintile group V versus I+II: 2.0 [1.2 to 3.5] and the subgroup free of atherosclerosis at the 1995 baseline: 3.8 [1.6 to 8.9]). The risk of early atherogenesis was additionally amplified when high-sHSP60 and chronic infection were present together. CONCLUSIONS: Our study provides the first prospective data confirming an association between high levels of sHSP60 and early carotid atherosclerosis. This possibly indicates an involvement of sHSP60 in activating proinflammatory processes associated with early vessel pathology

    Web service management system for bioinformatics research: a case study.

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    In this paper, we present a case study of the design and development of a Web Service management system for bioinformatics research. The described system is a prototype that provides a complete solution to manage the entire life cycle of Web services in bioinformatics domain, which include semantic service description, service discovery, service selection, service composition, service execution, and service result presentation. A challenging issue we encountered is to provide the system capability to assist users to select the "right" service based on not only functionality but also properties such as reliability, performance, and analysis quality. As a solution, we used both bioinformatics and service ontology to provide these two types of service descriptions. A service selection algorithm based on skyline query algorithm is proposed to provide users with a short list of candidates of the \best" service. The evaluation results demonstrate the eciency and scalability of the service selection algorithm. Finally, the important lessons we learned are summarized and remaining challenging issues are discussed as possible future research directions

    Reaction kinetic analysis of damage rate effects on defect structural evolution in Fe–Cu

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    In Fe–Cu alloys, Cu precipitates are formed during high-energy particle irradiation. If there exists energetic binding between vacancies and Cu atoms, vacancy clusters (voids) are formed in precipitates at an initial stage of irradiation, separate from voids in the matrix, because of the migration of Cu atoms with vacancies. In this paper, the damage rate dependence on the formation and annihilation of voids in the precipitates and in the matrix is simulated by reaction kinetic analysis. The initial formation of voids at precipitates, the annihilation of them with an increased dosage and new formation of voids in the matrix are simulated, and the results are compared with the experiments. In a high damage rate of 3.3 × 10^[−7] dpa/s, the formation of voids in Cu precipitates is not significant, but the formation of voids in the matrix is dominant, different from those in a low damage rate of 1.5 × 10^[−10] dpa/s

    Calculation of stress intensity factors in an isotropic multicracked plate: Part 2: Symbolic/numeric implementation

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    Analytical derivations of stress intensity factors (SIF's) of a multicracked plate can be complex and tedious. Recent advances, however, in intelligent application of symbolic computation can overcome these difficulties and provide the means to rigorously and efficiently analyze this class of problems. Here, the symbolic algorithm required to implement the methodology described in Part 1 is presented. The special problem-oriented symbolic functions to derive the fundamental kernels are described, and the associated automatically generated FORTRAN subroutines are given. As a result, a symbolic/FORTRAN package named SYMFRAC, capable of providing accurate SIF's at each crack tip, was developed and validated. Simple illustrative examples using SYMFRAC show the potential of the present approach for predicting the macrocrack propagation path due to existing microcracks in the vicinity of a macrocrack tip, when the influence of the microcrack's location, orientation, size, and interaction are taken into account

    Spin current diode based on an electron waveguide with spin-orbit interaction

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    We propose a spin current diode which can work even in a small applied bias condition (the linear-response regime). The prototypal device consists of a hornlike electron waveguide with Rashba spin-orbit interaction, which is connected to two leads with different widths. It is demonstrated that when electrons are incident from the narrow lead, the generated spin conductance fluctuates around a constant value in a wide range of incident energy. When the transport direction is reversed, the spin conductance is suppressed strongly. Such a remarkable difference arises from spin-flipped transitions caused by the spin-orbit interaction.Comment: 3 pages, 2 figure
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