31.   Research in diseases of the central nervous system, cancer and respiratory tract diseases will be conducted in Somerville, the company said.

32.   Singers, at the mercy of their respiratory tracts, are the most unpredictable.

33.   Synagis is a genetically engineered antibody that works to stop the virus from fusing with and infecting the cells of the respiratory tract.

34.   The bacteria are not those that cause the sexually transmitted disease chlamydia, but instead affect the respiratory tract.

35.   The CDC influenza surveillance system aims primarily at identifying the influenza virus, not the many other ones that are now causing upper respiratory tract infections.

36.   The chemicals can cause irritation to respiratory tracts, eyes, noses and skin, symptoms some of the workers have complained of.

37.   The company is about to begin clinical trials, using breath samples to detect infections in the upper respiratory tract.

38.   The drug is used primarily in hospitals to treat serious upper and lower respiratory tract infections such as bronchitis, pneumonia, and sinus problems.

39.   The flu is an infection of the respiratory tract that is caused by the influenza virus.

40.   The low humidity creates gaps in the mucous fining of the respiratory tract, which holds key immune cells.