The objective of the present paper is a numerical analysis of the flow forces acting on spool surfaces of a pressure regulated valve. The transient, compressible and turbulent flow structures inside the valve are simulated using ANSYS FLUENT coupled with a special UDF. Here, valve inlet pressure is varied in a stepwise manner. For every value of inlet pressure, transient analysis leads to a qua...

aesthetic lines after osteotomies, symmetries of the middle third. It is also used for functional recovery of opening the nasal valve. The evaluation of the results of spreader graft is difficult and subjective. Measuring nasal valve angle is an objectie criteria of functional outcome, the brow tip aesthetic lines referred by Tardy and Sheen are options for aesthetic evaluation. Our common indi...

Mitral valve repair is shown to have better survival, preservation of ventricular function and decreased thromboembolic complications compared to mitral valve replacement for mitral regurgitation (MR).13–15 At our institution, we have developed a simple algorithm for mitral valve repair in myxomatous disease, which allows reproducible and durable repair. Our general plan is described by the fol...

Abnormal electrical activation of the left ventricle results in mechanical dyssynchrony, which is in part characterized by early stretch of late-activated myofibers. To describe the pattern of deformation during "prestretch" and gain insight into its causes and sequelae, we implanted midwall and transmural arrays of radiopaque markers into the left ventricular anterolateral wall of open-chest, ...

Echocardiographic studies of the pulmonary valve were obtained in 63 adults. Patients with normal pulmonary artery pressure (22 cases) showed an oblique position of the valve images in diastole, slow valve opening slopes (< 300 mm/see), sizable (> 2 mm) posterior displacement of the cusp echoes with atrial systole ('a' dip), and a relatively short right ventricular pre-ejection period. In contr...

To examine the interaction between normal and nonischemic areas of the left ventricle during acute ischemia, we implanted midwall ultrasonic segment length gauges in the ischemic zone and in nonischemic areas of the canine left ventricle. During acute ischemia, end-diastolic pressure and segment length in the nonischemic areas increased. There was no change from control in the segment length at...

In this study, we report on our first experience with the construction of a valve using autologous vena cava tissue for right ventricular outflow tract reconstruction. Simulating the clinical situation valves were built from tubular pieces of porcine inferior vena cava placed in a PTFE tube and investigated in a pulsatile flow simulator. Based on the given vena cava dimensions, conduits were co...

Motion and position of both mitral leaflets were studied in five normal dogs 1-11 wk after radiopaque markers were sutured on the valve cusps and on the mitral annulus. Cinefluorograms and cineangiograms (100-120 frames/s) of left atrium and left ventricle were used to study cusp motion and intraventricular flow patterns, and to detect mitral regurgitation during sinus rhythm (42-184 beats/min)...

In this study, fuzzy expert system (FES) was designed by using Matlab software for determination of performance and emission characteristics of a gasoline engine which is Briggs and Stratton Vanguard trademark, a cylinder, cylinder volume 182 cm. In the designed FES, intake valve opening advance (advance-) and engine speed (nd/d) were determined as input parameters whereas torque (Me-Nm), power...

Does the opening pressure of hydrostatic shunts influence the clinical outcome for patients suffering from idiopathic normal-pressure hydrocephalus (NPH)? Between September 1997 and January 2003, 123 patients with idiopathic NPH were surgically treated by implanting a hydrostatic shunt at the Departments of Neurosurgery of the Unfallkrankenhaus Berlin and the University Homburg/Saar. As part of...