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People who have myopia, or nearsightedness, are not able to see objects at a distance but only up close. It occurs when the cornea is either curved too steeply, the eye is too long, or both. This condition is progressive and worsens with time. More than 100 million people in the United States are nearsighted, but only 20% of those are born with the condition. Diet, eye exercise, drug therapy, and corrective lenses can all help manage nearsightedness.
Interferon was scarce and expensive until 1980, when the interferon gene was inserted into bacteria using recombinant DNA technology, allowing for mass cultivation and purification from bacterial cultures.
Nitroglycerin is used to alleviate various heart-related conditions, and it is also the chief component of dynamite (but mixed in a solid clay base to stabilize it).
Blood is approximately twice as thick as water because of the cells and other components found in it.
Intradermal injections are somewhat difficult to correctly administer because the skin layers are so thin that it is easy to accidentally punch through to the deeper subcutaneous layer.