Millions of people around the U.S. are again under the threat of severe weather Friday.

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In 1st, U.S. Surgeons Transplant Pig Heart Into Human Patient
U.S. doctors have transplanted a pig heart into a patient in a last-ditch effort to save his life — a first for medical science. Doctors at University of Maryland School of Medicine said Monday the patient is doing well three days after surgery.
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