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Specific Devices (specific + device)
Selected AbstractsNew Technique for Fenestration of the Interatrial SeptumJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 4 2006MUTHUKUMARAN SIVAPRAKASAM M.R.C.P.C.H. Achieving controlled flow between the systemic and pulmonary venous circulations is desirable in many complex congenital heart diseases. This includes the Fontan circulation, primary pulmonary hypertension, double inlet ventricles, or hypoplastic left heart with obstruction to the atrioventricular valve. As no specific device is available for this purpose, we developed a balloon-mounted stent technique to achieve a predetermined-sized fenestration of an atrial baffle in a patient with Fontan circulation. The details of the technique are described. [source] Evaluation of drugs in pediatrics using K-PD models: perspectivesFUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 6 2008M. Tod Abstract Some pharmacodynamic (PD) models, called K-PD models, have been developed for the description of drug action kinetics in the absence of drug concentration measurements. Because blood samples for drug measurements are not needed, these models may be very useful in pediatric studies, by reducing their invasiveness. In addition, a number of PD measurements are also non-invasive and specific devices exist for measures in children. Therefore, the kinetics of drug action may be characterized with minimal invasiveness. A brief description of the key features of these models is given, and a number of examples of application are presented. K-PD models are expected to be most useful when the drug kinetics is simple (i.e. when the one-compartment model is a reasonable description), or when the response kinetics is slow compared with drug kinetics. K-PD models have already demonstrated their usefulness in animal and adult studies. They are very attractive for pediatric studies and they should facilitate the assessment of drug efficacy and safety. [source] A wavelet-based piecewise approach for steady-state analysis of power electronics circuitsINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 5 2006K. C. Tam Abstract Simulation of steady-state waveforms is important to the design of power electronics circuits, as it reveals the maximum voltage and current stresses being imposed upon specific devices and components. This paper proposes an improved approach to finding steady-state waveforms of power electronics circuits based on wavelet approximation. The proposed method exploits the time-domain piecewise property of power electronics circuits in order to improve the accuracy and computational efficiency. Instead of applying one wavelet approximation to the whole period, several wavelet approximations are applied in a piecewise manner to fit the entire waveform. This wavelet-based piecewise approximation approach can provide very accurate and efficient solution, with much less number of wavelet terms, for approximating steady-state waveforms of power electronics circuits. Copyright © 2006 John Wiley & Sons, Ltd. [source] Percutaneous Closure of Paravalvular LeaksJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 2006RALPH HEIN M.D. Paravalvular leak occurs in about 2,3% of patients after surgical valve replacement. The leak may cause heart failure, arrhythmias, or hemolysis. Patients who have had multiple operations or who have significant comorbidity constituting a contraindication to surgery might be considered candidates for transcatheter closure. In the past, occluding paravalvular leaks has been attempted using coils or double umbrella devices; defect specific devices are under development. Interventional experiences with various Amplatzer occluders are described. [source] Basic principles of radiotherapy in ophtalmic oncologyACTA OPHTHALMOLOGICA, Issue 2009R DENDALE Ophtalmologic Radiation Oncology concerns intra ocular tumors, orbital tumors and eyelid tumors. In these locations, tumors are often close to normal critical tissues, increasing the risk of radiation toxicities. Basic principles of ophthalmic radiotherapy are not really different from radiotherapy of others organs. They are based on a precise description of the tumor volume, knowledge of potential tumor local or regional extension, knowledge of tissue biological radiosensitivity for tumors and the surrounding normal tissues. Based on these features, treatment modalities (radiation treatment length and fractionation) are determined to fulfill the aims of medical curative intents: good local control with acceptable toxicities or the aims of medical palliative intents: to relief with minimal toxicities. Many types of radiation therapy can be used for ophthalmic tumors: brachytherapy, orthovoltage radiotherapy, conformal therapy with photons and electrons including intensity modulated radiation therapy, protontherapy, and the use of specific devices such as CyberKnife and Tomotherapy. All of these techniques have their advantages and their disadvantages, leading the radiation oncologist to make a choice depending on the tumor site and characteristics. [source] | ||||||||||