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.
Now a new type of elevator developed in Argentina looks set to revolutionise the residential lift market, making elevators affordable to everyone. The self-supporting vacuum elevator is constructed of aluminium and polycarbonate and takes just a few hours to install.