Years later during a random screening, the molecule exhibited herbicidal activity.

The strict no-smoking policy imposed random screenings, and termination upon failure of a test.

For some reason, I always make the random screening.

Two years ago, the state became the first to authorize random screening for steroids of any high school athlete whose team qualified for postseason play.

It does not differentiate between schools that do intensive, regular random screening and those that test only occasionally.

Mr. Safir predicts that business travelers will encounter an increase in random screenings.

At most schools with testing programs, students who want to participate in extracurricular activities must agree to random screening, and parents must sign a consent form.

At present these green deformities served only to provide random screening for anyone approaching the house.

If the random screening occurred at his school, "many people would be very upset," he said, adding, "An emergency happens almost every day at school."

He described an incident when he groaned, "Oh, man," as he was pulled aside for a random screening.