THE thermionic valve has long been recognized as a useful tool in many branches of science and engineering; but few, with the exception of experimenters, have realized that it can be usefully applied ...

There are three types of bicuspid aortic valves — types 0, 1, and 2. Experts classify these types based on whether the leaflets of the valve have fused to form a ridge. A bicuspid aortic valve is a ...