41.   The new test measures the levels of two enzymes in the blood.

42.   The ozone level is measured to determine attainment of federal air quality standards.

43.   The researchers measured levels of a protein called transcription factor Fos, which is produced by the part of the rat brain that contains the pacemaker.

44.   The rats have been given micro-thin implants that can measure the levels of chemicals in the brain.

45.   The state agency plans to measure levels along the Colorado, within the CAP systems and in a number of groundwater wells again later this year.

46.   The study sought to determine whether measuring the levels of such chemicals could predict violent behavior.

47.   The two psychologists set up a series of controlled tests to measure levels of the hormones testosterone and cortisol in various men following staged confrontations.

48.   Their homocysteine levels were measured and their health was monitored for eight years.

49.   Their ghrelin levels were measured before they began dieting and then six months later.

50.   They asked about exposure to smoke on the job and at home, and measured levels of cotinine, a byproduct of nicotine, a key ingredient in cigarettes.