569 research outputs found
How rare is isolated rheumatic tricuspid valve disease?
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
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
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
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
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
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 , in which every node has a size
and profit , and the size limitation . The target is to find a subset
of subtrees rooted at nodes respectively such that
, and 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?
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
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
118103Theoretical Physic
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