Here's what I found a while back when seeking info about tumor necrosis. 1) Necrosis in the tumor means that the cancer cells in that area are dead. The pathologic finding of necrosis suggests a fast-growing cancer. This often happens because the tumor runs out of blood supply in the central portion. Without a blood supply, the tumor cells cannot live.
In association football, where the shoes themselves are known as football boots, there are three different cleat types. There are soft ground cleats which are made for wet weather. The soft ground cleats are always replaceable, and are almost always metal, so when they wear down they are easy to replace.
How NFL Equipment Works. Without hand protection, receivers wouldn't be able to catch the ball, and without foot protection, the players would constantly be subject to injury. This is why gloves and shoes, or cleats, are so important. Many receivers wear gloves that either have a sticky rubber palm, called tact gloves, or are covered with a sticky substance like rosin or a sticky spray. Linemen also wear gloves -- they don't have to catch the ball, but they do have to use their hands to fight off opposing linemen.