534 research outputs found
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Model National Implementing Legislation for the Chemical Weapons Convention
It is an honor to address this distinguished audience. We are grateful to the Republique Gabonaise for hosting this important gathering and to the staff of the Organization for the Prohibition of Chemical Weapons (OPCW) for supporting it. This seminar is another excellent opportunity for all of us to learn from each other about how the Chemical Weapons Convention (CWC) can become a foundation of arms control in Africa and around the world. At this meeting we speak only for ourselves, neither for the government of the United States of America nor for any other institution. This paper discusses model national implementing legislation under the CWC. Every State Party likely must enact implementing legislation - not only the few States Parties that will declare and destroy chemical weapons, but also the many States Parties that have never had a chemical weapons programme
Pulmonary artery pressure is associated with extracellular volume fraction in patients with normal left ventricular function
Optimized saturation recovery protocols for T1-mapping in the heart: influence of sampling strategies on precision
Increased cardiac involvement in Fabry disease using blood-corrected native T1 mapping
Fabry disease (FD) is a rare lysosomal storage disorder resulting in myocardial sphingolipid accumulation which is detectable by cardiovascular magnetic resonance as low native T1. However, myocardial T1 contains signal from intramyocardial blood which affects variability and consequently measurement precision and accuracy. Correction of myocardial T1 by blood T1 increases precision. We therefore deployed a multicenter study of FD patients (n = 218) and healthy controls (n = 117) to investigate if blood-correction of myocardial native T1 increases the number of FD patients with low T1, and thus reclassifies FD patients as having cardiac involvement. Cardiac involvement was defined as a native T1 value 2 standard deviations below site-specific means in healthy controls for both corrected and uncorrected measures. Overall low T1 was 135/218 (62%) uncorrected vs. 145/218 (67%) corrected (p = 0.02). With blood-correction, 13/83 previously normal patients were reclassified to low T1. This reclassification appears clinically relevant as 6/13 (46%) of reclassified had focal late gadolinium enhancement or left ventricular hypertrophy as signs of cardiac involvement. Blood-correction of myocardial native T1 increases the proportion of FD subjects with low myocardial T1, with blood-corrected results tracking other markers of cardiac involvement. Blood-correction may potentially offer earlier detection and therapy initiation, but merits further prospective studies
High spatial and temporal resolution retrospective cine cardiovascular magnetic resonance from shortened free breathing real-time acquisitions
Extracellular volume fraction is associated with B-type natriuretic peptide in hypertrophic cardiomyopathy
Hypertrophic cardiomyopathy is a common cardiovascular genetic disease characterized by sarcomeric gene mutations which lead to findings of cardiac hypertrophy, myocyte disarray, and fibrosis. While late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) detects focal, macroscopic regions of replacement fibrosis non-invasively, novel T1 CMR measurement techniques including extracellular volume fraction (ECV) diffuse interstitial fibrosis throughout the myocardium. Plasma B-type natriuretic peptide levels are often elevated in situations of increased wall tension and volume overload. Given that such states may be associated with myocardial fibrosis, and because BNP levels provide independent prognostic insight in HCM, we sought to determine the association between BNP and ECV measurement by CMR
A consensus statement by the Society for Cardiovascular Magnetic Resonance (SCMR) endorsed by the European Association for Cardiovascular Imaging (EACVI)
Parametric mapping techniques provide a non-invasive tool for quantifying
tissue alterations in myocardial disease in those eligible for cardiovascular
magnetic resonance (CMR). Parametric mapping with CMR now permits the routine
spatial visualization and quantification of changes in myocardial composition
based on changes in T1, T2, and T2*(star) relaxation times and extracellular
volume (ECV). These changes include specific disease pathways related to
mainly intracellular disturbances of the cardiomyocyte (e.g., iron overload,
or glycosphingolipid accumulation in Anderson-Fabry disease); extracellular
disturbances in the myocardial interstitium (e.g., myocardial fibrosis or
cardiac amyloidosis from accumulation of collagen or amyloid proteins,
respectively); or both (myocardial edema with increased intracellular and/or
extracellular water). Parametric mapping promises improvements in patient care
through advances in quantitative diagnostics, inter- and intra-patient
comparability, and relatedly improvements in treatment. There is a multitude
of technical approaches and potential applications. This document provides a
summary of the existing evidence for the clinical value of parametric mapping
in the heart as of mid 2017, and gives recommendations for practical use in
different clinical scenarios for scientists, clinicians, and CMR
manufacturers
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DESIGN, FABRICATION, INSTALLATION, TESTING AND INITIAL RESULTS OF IN-VESSEL CONTROL COILS FOR DIII-D
OAK-B135 Since 1995, DIII-D has performed correction of magnetic field imperfections using a set of six external picture frame coils located on the vessel mid-plane. In 2000, these coils also demonstrated benefits when used for feedback of the resistive wall mode, an instability that limits the plasma performance at high beta. Modeling has shown that substantial performance improvements could be achieved by installing new coils inside the vessel and expanding the poloidal coverage above and below the mid-plane. Two prototype internal coils were installed in 2001 and were power tested successfully after several bakes to 350 C. A full set of twelve internal coils and related magnetic sensors are now operational in the DIII-D tokamak. The design requirements for the new coil system was to maximize the magnetic field at the plasma edge, operate with a frequency range of dc to 1000 Hz, and fit behind the existing graphite wall tiles. The coil design adopted and installed is a water-cooled hollow copper conductor insulated with polyamide and housed inside a stainless steel tube that forms a vacuum boundary. The coil is rigidly mounted to the inside of the vacuum vessel. The primary challenge in the design of these coils wa sin joining of both the copper conductor and the stainless tube without overheating the polyamide insulator. Elastic-plastic analysis was used to demonstrate acceptable thermal stresses during baking conditions. Analysis determined the optimum water cooling channel diameter. The coils were tested in high toroidal field to the limit of the power supply of 4.5 kA DC with inductance-limited current for frequencies between 300 Hz and 1000 Hz. Recent results are presented
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Accuracy and reproducibility of four T1 mapping sequences: a head-to-head comparison of MOLLI, ShMOLLI, SASHA, and SAPPHIRE
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