Chronic granulomatous disease (CGD) is a rare (â¼1:250,000 births) disease caused by mutations in any one of the five components of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in phagocytes. This enzyme generates superoxide and is essential for intracellular killing of pathogens by phagocytes.
Vehicles for human transport that have two wheels and require balancing by the rider date back to the early 19th century. The first means of transport making use of two wheels arranged consecutively, and thus the archetype of the bicycle, was the German draisine dating back to 1817. The term bicycle was coined in France in the 1860s.
History of the motorcycle. The history of the motorcycle begins in the second half of the 19th century. Motorcycles are descended from the safety bicycle, a bicycle with front and rear wheels of the same size and a pedal crank mechanism to drive the rear wheel.