|
|
The lipid bilayer is made of phospholipids. They are arranged in a double layer because one of their ends is attracted to water while the other is repelled by water.
Before a vaccine is licensed in the USA, the Food and Drug Administration (FDA) reviews it for safety and effectiveness. The CDC then reviews all studies again, as well as the American Academy of Pediatrics and the American Academy of Family Physicians. Every lot of vaccine is tested before administration to the public, and the FDA regularly inspects vaccine manufacturers' facilities.
In 2012, nearly 24 milliion Americans, aged 12 and older, had abused an illicit drug, according to the National Institute on Drug Abuse (NIDA).
As of mid-2016, 18.2 million people were receiving advanced retroviral therapy (ART) worldwide. This represents between 43–50% of the 34–39.8 million people living with HIV.
After a vasectomy, it takes about 12 ejaculations to clear out sperm that were already beyond the blocked area.