11.   When chemical reactions occur energy is usually liberated as heat just as the ball loses potential energy as it moves downslope.

12.   Avoid using acrylic paint-on, porcelain, or glue-on nails because painful reactions can occur and long-term use may scar the nail bed.

13.   A serious rejection reaction can occur at any time after any transplant.

14.   Although a skin biopsy showed no evidence of rejection last week, such a reaction can occur at any time.

15.   Eight Texas deaths have been linked to ephedrine in the past four years, state health officials said, and many adverse reactions occurred in children and teen-agers.

16.   Elkins of the FDA said no scientific evidence had been found to support the theory that the adverse reaction occurs in humans.

17.   Even bites from nonpoisonous snakes should be treated professionally, as severe allergic reactions can occur.

18.   If such a reaction occurs in Hallam, his doctors said, they are confident they can control it with standard drugs.

19.   In Tokaimura, the experts said, the radioactive materials were almost entirely contained in the vessel where the reaction occurred.

20.   Life-threatening reactions usually occur in people who are already sensitized to latex proteins.