391 research outputs found

    An outline of agriculture in the Europe Union countries and Hungary.

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    論文http://purl.org/coar/resource_type/c_650

    Electrophysiologic Studies and Radiofrequency Catheter Ablation of Ectopic Atrial Tachycardia in Children

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    Ectopic atrial tachycardia (EAT) often resists medical therapy, making radiofrequency catheter ablation (RFCA) the preferred treatment. This study reviewed the records of 35 patients who underwent electrophysiologic studies (EPS) and 39 RFCA procedures for EAT during a 10-year period. Of the 35 patients, 10 (28%) presented with decreased ventricular function and tachycardia-induced cardiomyopathy (TIC). The EAT originated on the right atrial side in 19 patients (54%) and on the left atrial side in the remaining 16 patients (46%). The right atrial sites included the right atrial appendage (RAA) (n = 9, 25%), the tricuspid annulus (n = 7, 20%), and the crista terminalis (n = 3). The left atrial sites included the left atrial appendage (LAA) (n = 6, 17%), the pulmonary veins (n = 5, 14%), the mitral annulus (n = 3), and the posterior wall of the left atrium (n = 2). The mechanism of all EAT probably is automaticity. All EATs could be abolished using RFCA. Follow-up data were available for all patients 2 to 8 years after RFCA. All 35 patients remained recurrence free, and ventricular function improved for all 10 patients with TIC. The origin of EAT in children differed from its origin in adults. The authors conclude that RFCA is a safe and effective treatment option for children with refractory EAT and should be considered early in the course of their illness

    Compressive properties of commercially available polyurethane foams as mechanical models for osteoporotic human cancellous bone

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    <p>Abstract</p> <p>Background</p> <p>Polyurethane (PU) foam is widely used as a model for cancellous bone. The higher density foams are used as standard biomechanical test materials, but none of the low density PU foams are universally accepted as models for osteoporotic (OP) bone. The aim of this study was to determine whether low density PU foam might be suitable for mimicking human OP cancellous bone.</p> <p>Methods</p> <p>Quasi-static compression tests were performed on PU foam cylinders of different lengths (3.9 and 7.7 mm) and of different densities (0.09, 0.16 and 0.32 g.cm<sup>-3</sup>), to determine the Young's modulus, yield strength and energy absorbed to yield.</p> <p>Results</p> <p>Young's modulus values were 0.08–0.93 MPa for the 0.09 g.cm<sup>-3 </sup>foam and from 15.1–151.4 MPa for the 0.16 and 0.32 g.cm<sup>-3 </sup>foam. Yield strength values were 0.01–0.07 MPa for the 0.09 g.cm<sup>-3 </sup>foam and from 0.9–4.5 MPa for the 0.16 and 0.32 g.cm<sup>-3 </sup>foam. The energy absorbed to yield was found to be negligible for all foam cylinders.</p> <p>Conclusion</p> <p>Based on these results, it is concluded that 0.16 g.cm<sup>-3 </sup>PU foam may prove to be suitable as an OP cancellous bone model when fracture stress, but not energy dissipation, is of concern.</p

    LEPROSY SURVEY AT YONAKUNIJIMA

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    Should Catheter Ablation Be Indicated Only for Symptom-Relief of AF?

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    Frontier of catheter ablation for atrial fibrillation

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    SummaryThe sudden evolution of catheter ablation (CA) therapy for atrial fibrillation (AF) was brought by the discovery of a new insight into the triggering mechanism of AF by Haïssaguerre et al. in 1998. This discovery opened a new era of evolution of ablation therapy of paroxysmal AF (PAF). At the frontier of AF ablation, technical development of CA for long-standing persistent AF (CAF) has been done enthusiastically, although the detailed electrophysiologic mechanism and anatomical substrate of persistent AF remain unknown. Stepwise ablation composed of multiple procedures, circumferential pulmonary vein isolation (PVI), biatrial defragmentation, and anatomical linear ablation with the endpoint of AF termination has been the most widely accepted method, because the efficacy of this method was reported to be surprisingly high during a relatively short duration of follow-up. Recently, they showed this strategy has a significant limitation in efficacy for CAF with long AF duration (>7 years), enlarged left atrium (>50mm in left anterior descending artery), short AF cycle length (AFCL) (<130ms) and impaired cardiac function. For cases associated with these clinical, anatomical, and electrophysiological parameters, AF termination as an endpoint might be abandoned if peak prolongation of AFCL, reduction of intra-/inter-atrial AFCL gradient, and low defibrillation threshold are attained after predetermined lesion set is completed. Prolonged procedure with massive tissue ablation to attain AF termination should be avoided, because it potentially increases adverse events during and immediately after the procedure and causes extensive scar-formation in both atria with atrial mechanical dysfunction
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