569 research outputs found

    How rare is isolated rheumatic tricuspid valve disease?

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    The incidence of rheumatic fever (RF) has markedly decreased in Europe since the beginning of the 20th century due to improved living conditions, early antibiotic therapy in streptococcal pharyngitis, and changes in serotypes of circulating streptococci. Isolated outbreaks of RF are still found in various parts of the world and the disease has changed its presentation with milder joint symptoms and subclinical carditis that make the correct diagnosis more difficult. Patients can present many years later with severe valve disease and significant disability. This article presents a case of isolated rheumatic tricuspid valve disease that presented with signs and symptoms of right heart failure and severe valve damage. Isolated involvement of the tricuspid valve is rarely found in rheumatic fever and a thorough differential diagnosis is needed

    The effectiveness of the cardiac resynchronization in a patient with ischemic cardiomyopathy

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    Cardiac resynchronization therapy (CRT) in multiple and large trials has been demonstrated to improve symptoms and decrease hospitalization and mortality of patients when used in addition to optimal medical therapy. The global mechanical performance of the heart is affected in subjects with heart failure by atrio-ventricular, interventricular, or intraventricular conduction disorders, which lead to the desynchronization of electrical activity. Cardiac resynchronization therapy can effectively improve the clinical and haemodynamic status of these patients. According to literature data, CRT is performed only on well-selected patients (who qualify for CRT based on current indications), and approximately 70% of those patients respond favorably. We present the case of a patient responsive to cardiac resynchronization therapy which led to lowering of his NYHA classification and to improvement of left ventricle hemodynamics. The benefits of cardiac resynchronization therapy were multiple in this case, including improved tolerance to physical exercise and a decreased rate of hospitalization, which overall led to improved quality of life

    Inversion formulas for the broken-ray Radon transform

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    We consider the inverse problem of the broken ray transform (sometimes also referred to as the V-line transform). Explicit image reconstruction formulas are derived and tested numerically. The obtained formulas are generalizations of the filtered backprojection formula of the conventional Radon transform. The advantages of the broken ray transform include the possibility to reconstruct the absorption and the scattering coefficients of the medium simultaneously and the possibility to utilize scattered radiation which, in the case of the conventional X-ray tomography, is typically discarded.Comment: To be submitted to Inverse Problem

    Self-optimization of optical confinement in ultraviolet photonic crystal slab laser

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    We studied numerically and experimentally the effects of structural disorder on the performance of ultraviolet photonic crystal slab lasers. Optical gain selectively amplifies the high-quality modes of the passive system. For these modes, the in-plane and out-of-plane leakage rates may be automatically balanced in the presence of disorder. The spontaneous optimization of in-plane and out-of-plane confinement of light in a photonic crystal slab may lead to a reduction of the lasing threshold.Comment: 5 pages, 5 figure

    Microscopic derivation of the Jaynes-Cummings model with cavity losses

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    In this paper we provide a microscopic derivation of the master equation for the Jaynes-Cummings model with cavity losses. We single out both the differences with the phenomenological master equation used in the literature and the approximations under which the phenomenological model correctly describes the dynamics of the atom-cavity system. Some examples wherein the phenomenological and the microscopic master equations give rise to different predictions are discussed in detail.Comment: 9 pages, 3 figures New version with minor correction Accepted for publication on Physical Review

    XML Reconstruction View Selection in XML Databases: Complexity Analysis and Approximation Scheme

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    Query evaluation in an XML database requires reconstructing XML subtrees rooted at nodes found by an XML query. Since XML subtree reconstruction can be expensive, one approach to improve query response time is to use reconstruction views - materialized XML subtrees of an XML document, whose nodes are frequently accessed by XML queries. For this approach to be efficient, the principal requirement is a framework for view selection. In this work, we are the first to formalize and study the problem of XML reconstruction view selection. The input is a tree TT, in which every node ii has a size cic_i and profit pip_i, and the size limitation CC. The target is to find a subset of subtrees rooted at nodes i1,⋯ ,iki_1,\cdots, i_k respectively such that ci1+⋯+cik≤Cc_{i_1}+\cdots +c_{i_k}\le C, and pi1+⋯+pikp_{i_1}+\cdots +p_{i_k} is maximal. Furthermore, there is no overlap between any two subtrees selected in the solution. We prove that this problem is NP-hard and present a fully polynomial-time approximation scheme (FPTAS) as a solution

    How rare is isolated rheumatic tricuspid valve disease?

    Get PDF
    The incidence of rheumatic fever (RF) has markedly decreased in Europe since the beginning of the 20th century due to improved living conditions, early antibiotic therapy in streptococcal pharyngitis, and changes in serotypes of circulating streptococci. Isolated outbreaks of RF are still found in various parts of the world and the disease has changed its presentation with milder joint symptoms and subclinical carditis that make the correct diagnosis more difficult. Patients can present many years later with severe valve disease and significant disability. This article presents a case of isolated rheumatic tricuspid valve disease that presented with signs and symptoms of right heart failure and severe valve damage. Isolated involvement of the tricuspid valve is rarely found in rheumatic fever and a thorough differential diagnosis is needed

    The effectiveness of the cardiac resynchronization in a patient with ischemic cardiomyopathy

    Get PDF
    Cardiac resynchronization therapy (CRT) in multiple and large trials has been demonstrated to improve symptoms and decrease hospitalization and mortality of patients when used in addition to optimal medical therapy. The global mechanical performance of the heart is affected in subjects with heart failure by atrio-ventricular, interventricular, or intraventricular conduction disorders, which lead to the desynchronization of electrical activity. Cardiac resynchronization therapy can effectively improve the clinical and haemodynamic status of these patients. According to literature data, CRT is performed only on well-selected patients (who qualify for CRT based on current indications), and approximately 70% of those patients respond favorably. We present the case of a patient responsive to cardiac resynchronization therapy which led to lowering of his NYHA classification and to improvement of left ventricle hemodynamics. The benefits of cardiac resynchronization therapy were multiple in this case, including improved tolerance to physical exercise and a decreased rate of hospitalization, which overall led to improved quality of life

    Kinetic control of nucleosome displacement by ISWI/ACF chromatin remodelers

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    118103Theoretical Physic
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