Background. Although Doppler echocardiography has been shown to be accurate in assessing stenotic orifice areas in native valves, its accuracy in evaluating the prosthetic valve orifice area remains undetermined. Methods and Results. Doppler-estimated valve areas were studied for their agreement with catheterderived Gorlin effective orifice areas and their flow dependence in five sizes (19/20-2...

OBJECTIVES We used the Doppler proximal flow convergence technique as a physiologic tool to explore the effects of the time courses of mitral annular area and transmitral pressure on dynamic changes in regurgitant orifice area. BACKGROUND In functional mitral regurgitation (MR), regurgitant flow rate and orifice area display a unique pattern, with peaks in early and late systole and a midsyst...

Previous investigations have shown that the size of a regurgitant jet as assessed by color Doppler flow mapping is independently affected by the flow rate and velocity (or driving pressure) of the jet. Fluid dynamics theory predicts that jet momentum (given by the orifice flow rate multiplied by velocity) should best predict the appearance of the jet in the receiving chamber and also that this ...

INTRODUCTION This in vitro study compared the coronal microleakage of mineral trioxide aggregate (MTA), calcium-enriched mixture (CEM) cement and Biodentine as intra-orifice barriers. METHODS AND MATERIALS The study was conducted on 76 extracted single-canal human teeth. Their root canals were prepared using ProTaper rotary files and filled with gutta percha and AH-26 sealer using lateral con...

are presented. There are three types: (1) straddling tricuspid orifice entering both primitive ventricles with the mitral valve entering the left ventricle (nine cases), (2) displaced tricuspid orifice into the primitive left ventricle, with no A-V orifice in the primitive right ventricle (three cases), and (3) displaced tricuspid orifice with straddling mitral valve, in which the mitral valve ...

introduction: coronal microleakage is the major cause of failure of root canal treatments. the purpose of this study was to evaluate the sealing ability of white mta, c&b; metabond and cavit against coronal microleakage of enterococcus faecalis for four months. methods and materials: ninety extracted single–rooted human teeth were selected. root canal instrument-tation and abturation with gutta...

The present paper represents a methodology for investigating flow characteristics near orifice plate by using a commercial computational fluid dynamics code. The flow characteristics near orifice plate which is located in the auxiliary feedwater system were modeled via three different levels of grid and four different types of Reynolds Averaged Navier-Stokes (RANS) equations with proper near-wa...

Since the first transgastric natural orifice transluminal endoscopic surgery was described, various applications and modified procedures have been investigated. Transgastric natural orifice transluminal endoscopic surgery for periotoneoscopy, cholecystectomy, and appendectomy all seem viable in humans, but additional studies are required to demonstrate their benefits and roles in clinical pract...

Numerical investigation of gravity flow of granular solids in a hopper through orifices of different shapes has been conducted using the discrete element method. The simulations are validated by comparing with the experimental results for rapeseed cases. It is observed that with orifices of the same area the flow rate decreases in the order of circle, square, rectangle and triangle, which is si...