I've seen dynamic memory work better with other guests though, so it might be either something I'm doing wrong, or a side effect of the File Server role. Either way, I've gotten better results with setting static amounts of RAM on my file/DFS servers.
A biological heart valve is a heart valve recovered from a donor or created from donor tissue. A cadaveric valve comes from a human donor. Bovine valves are recovered from cows and porcine valves come from pigs.
There are four heart valves in a healthy human heart. The valves help to maintain proper blood flow through the heart, keeping blood moving efficiently and smoothly, and in the right direction. In addition to the valves there are four heart chambers -- the upper chambers are called the left and right atrium, the lower chambers are the left and right ventricle. A healthy heart valve will stop blood from flowing out of a heart chamber until it is time for the heart to pump the blood to its next destination.