In HIT, the immune system forms antibodies against heparin when it is bound to a protein called platelet factor 4 (PF4). These antibodies are usually of the IgG class and their development usually takes about five days.
The first elevator shaft preceded the first elevator by four years. Construction for Peter Cooper's Cooper Union Foundation building in New York began in 1853. An elevator shaft was included in the design, because Cooper was confident that a safe passenger elevator would soon be invented.
Alexander Miles: Well, when i first got interested in improving the elevator, I found that not many people had found much interest in it before me. Most of my ideas however, were built mainly off of the work that Sir William Armstrong had done on the elevator.