COMPLETE valvular replacement is the only feasible method for treatment of many cases of aortic valvular disease. While the long-term results will not be known for some time, the prognosis without operation, in carefully selected patients, is so poor as to justify this approach. Our total experience, consisting of a group of 16 such patients undergoing aortic replacement with the ballvalve pros...

In I944 Dr. Charles Hufnagel began experimental work on animals in attempts to evolve a suitable valve for the treatment of aortic insufficiency. He has, over a number of years since, used a variety of material, including homologous valves, pericardium, veins, etc., but none was satisfactory, as they all showed signs of wear and tear in the long run. This led to the design of a plastic valve. T...

INTRODUCTION/PURPOSE Although metal baseball bats are widely believed to outperform wood bats, there are few scientific studies which support this. In a batting cage study, Greenwald et al. found that baseballs hit with a metal bat traveled faster than those hit with a wood bat, but the factors responsible for this difference in bat performance remain unidentified. The purpose of this study was...