Pulmonary arterial hypertension is a rare but severe disease with an estimated five-year survival rate of only 57% after diagnosis, according to the Registry to Evaluate Early And Long-term PAH disease management (REVEAL), which registers data from patients in the United States.
Concentration of elements in the ocean relative to the total concentration in the bulk silicate Earth (BSE). Of all the elements, only Cl and Br have a significant fraction in the ocean (see inset), indicating the extreme hydrophilic character for the heavier halogens.
Chlorine in Nature. Chlorine is a highly reactive element which practically does not exist by itself in nature, but only in combination with other elements. In some rare situations, such as in human tears, free chlorine as such can be detected. It is one of the most common elements in nature, where it is even more plentiful than carbon. Among the inorganic chlorinated substances, common salt is of course the best example.