Ammonia and the Haber process. Ammonia. Ammonia (NH3) is a compound [compound: A compound is a substance formed by the chemical union (involving bond formation) of two or more elements. ] of nitrogen and hydrogen. It is a colourless gas with a choking smell, and a weak alkali which is very soluble in water.
Latent tuberculosis infection (LTBI) is a condition in which a person is infected with M. tuberculosis, but does not currently have active tuberculosis disease.
Doctors make a distinction between two kinds of tuberculosis infection: latent and active. In latent TB, the TB bacteria remain in the body in an inactive state. They cause no symptoms and are not contagious, but they can become active. About one-third of the world's population is believed to have latent TB.