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When blood is exposed to air, it clots. Heparin allows the blood to come in direct contact with air without clotting.
There are more nerve cells in one human brain than there are stars in the Milky Way.
A cataract is a clouding of the eyes' natural lens. As we age, some clouding of the lens may occur. The first sign of a cataract is usually blurry vision. Although glasses and other visual aids may at first help a person with cataracts, surgery may become inevitable. Cataract surgery is very successful in restoring vision, and it is the most frequently performed surgery in the United States.
This year, an estimated 1.4 million Americans will have a new or recurrent heart attack.
More than 2,500 barbiturates have been synthesized. At the height of their popularity, about 50 were marketed for human use.