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The angular momentum balance is solved numerically for a size 29 mm CarboMedics prosthetic heart valve. The lift force is estimated from potential flow theory, while the drag force is estimated from the lift force and a blunt body empiricism. Buoyancy and gravitational effects are calculated based on the assumption of homogeneous leaflets. Other assumptions(More)
We present empirical evidence on gender differences in wage returns on firmspecific experience (job tenure) and general experience. We find that overall returns on an extra year of labor market experience are lower for women than men. However, a decomposition analysis shows that the return on job tenure is substantially lower for women than it is for men,(More)
OBJECTIVE To study the cause of myocardial rupture and its related complications using a computer-assisted model of left ventricular (LV) function following acute myocardial infarction. DESIGN A model previously described by other authors was modified. The LV was portrayed as a three-layered ellipsoid at end-diastolic volume (135 mL). The aspect ratio of(More)
Clinically significant, unexplained hemolysis has been reported to occur in St Jude Medical (SJM) cardiac valve prostheses. The leakage phase of backflow is identified as having the most hemolytic potential, when compared with the other phases of the cardiac cycle. A two-dimensional, laminar, constant fluid property finite element analysis (FEA) is used to(More)
Strut fracture, with embolization of the disc occluder, caused the death of a 64-year-old man who had a Beall model 105 heart valve prosthesis in the mitral position for 13 years. Scanning electron microscopy of the fractured surface revealed evidence of a fatigue failure mechanism in the metal wire. The case is unique in that strut fractures affecting this(More)
Ten Lillehei-Kaster heart valve prostheses, in situ for up to 10 years and recovered at surgery or necropsy, were examined by light and scanning electron microscopy. All showed metal wear on the luminal aspect of their struts. The volume of wear related to the duration a prosthesis had been in situ. The worn metal showed distinct, transverse surface(More)
Newton's second law of motion for rotating bodies and potential flow theory is used to mathematically model the closing process of a pivoting disc prosthetic heart valve in mitral position. The model predicts closure to be dependent upon disc curvature, eccentricity, mass, diameter, density, opening angle and fluid properties. Experiments using two(More)
Measurements of the steady-state leakage of the new Medical Incorporated Omniscience/tm cardiac valve prosthesis are presented. These results are compared to those obtained from the SJM bi-leaflet cardiac valve/tm. The new Omniscience/tm valve shows significantly less leakage than the bi-leaflet valve. Consideration is given to problems in similitude as(More)
An approximate hemodynamic theory, which predicts the opening dynamics of the Lillehei-Kaster heart valve, is used in conjunction with an abrasive wear model to predict the wear process on the shields. The hemodynamic theory predicts markedly different opening dynamics between the mitral and aortic positions and is shown to give excellent correlation with(More)
The pressure-flow rate characteristics of two new convex-concave pivoting disc prosthetic heart valves are evaluated in vitro. The Omniscience and Björk-Shiley prostheses are chosen since both use curved occluders with similar dynamic function, but with different occluder curvature and eccentricity. The Omniscience prosthesis is shown to have consistently(More)