INTRODUCTION The cause of ascending aortic dilatation occurring in patients with congenitally bicuspid aortic valves was investigated. METHODS Flow patterns through human aortic roots with congenitally bicuspid aortic valves as well as through porcine constricted aortas were studied in a left heart simulator. Vibration was recorded as a measure of turbulence in the post-stenotic segment. Hist...

A new procedure for deriving nonlinear mathematical modeling for a specific class of aerospace hydro - mechanical control valves is presented. The effects of friction on the dynamic behavior of these types of valves along with the experimental verifictions are also given. The modeling approach is based on the combination of the following three tasks: decomposition of the valve into simple speci...

To date, vertebral venous valves have not been studied clinically or by sonography. This report reveals that these valves could be studied noninvasively by using sonographic techniques. Real-time sonography clearly showed the opening and closing of the two cusps of vertebral venous valves at the junction of the vertebral vein and the brachiocephalic vein, which move synchronously with the inter...

The study was performed on 82 small saphenous veins in human fetuses of both sexes aged 9 to 37 weeks. The earliest valves were observed in 13 week-old fetuses. In fetuses between 13 and 18 weeks old the number of valves increased from 1 to 8. In the older fetuses between 19 and 37 weeks the number of valves varied from 5 to 9 and does not seem to be related to age. During development more valv...

Server Push, one of the most promising features of HTTP/2, allows web servers to speculatively send unsolicited web resources to clients. While the mechanism for Push is well defined, policies for effectively utilizing push to maximize page load performance are poorly understood. In this work we investigate the factors that should be considered when implementing a Push policy and combine them t...

In 1992, based on extensive review of the literature, we concluded that in patients with mechanical prosthetic heart valves,1 (1) long-term (permanent) therapy with oral anticoagulants offers the most consistent protection, and (2) levels of oral anticoagulants that prolong the prothrombin time (PT) ratio to an international normalized ratio (INR) of 2.5 to 3.5 are satisfactory for tilting disk...

OBJECTIVES Proper valve selection is critical to ensure appropriate valve replacement for patients, because implantation of a small valve might place the patient at risk for persistent gradients. Labeled valve size is not the same as millimeter measure of prosthetic valve diameters or the annulus into which it will fit. Studies that use the labeled valve size in lieu of actual measured diameter...

OBJECTIVE To investigate the possible role of elastolytic cathepsins S, K, and V and their endogenous inhibitor cystatin C in adverse extracellular matrix remodeling of stenotic aortic valves. METHODS AND RESULTS Stenotic aortic valves were collected at valve replacement surgery and control valves at cardiac transplantations. The expression of cathepsins S, K, and V and cystatin C was studied...

PURPOSE Only mechanical and biological heart valve prostheses are currently commercially available. The former show longer durability but require anticoagulant therapy; the latter display better fluid dynamic behavior but do not have adequate durability. New Polymeric Heart Valves (PHVs) could potentially combine the hemodynamic properties of biological valves with the durability of mechanical ...