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Astigmatism is the most common vision problem. It may accompany nearsightedness or farsightedness. It is usually caused by an irregularly shaped cornea, but sometimes it is the result of an irregularly shaped lens. Either type can be corrected by eyeglasses, contact lenses, or refractive surgery.
Always store hazardous household chemicals in their original containers out of reach of children. These include bleach, paint, strippers and products containing turpentine, garden chemicals, oven cleaners, fondue fuels, nail polish, and nail polish remover.
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.
More than 2,500 barbiturates have been synthesized. At the height of their popularity, about 50 were marketed for human use.
The ratio of hydrogen atoms to oxygen in water (H2O) is 2:1.