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.
Building a Business. With his two sons, Otis founded the Union Elevator and General Machine Works Company. He debuted his invention at New York's Crystal Palace Exhibition in 1853. The impresario P. T. Barnum was there to hype the stunt and attract a crowd. Otis's alarming demonstration increased orders for his hoist machines.. Otis, a compulsive tinkerer, made numerous improvements to his elevator and patented other inventions, but he never managed to run a successful business.