It is for this reason that is referred to as a complementary DNA or cDNA. Though there are numerous processes for synthesizing cDNA, the best way of doing so is by using mature or fully spliced mRNA. This is usually done by using the enzyme reverse transcriptase.
Ammonia is used as refrigerant prominently in the refrigeration systems of food industry like dairies, ice creams plants, frozen food production plants, cold storage warehouses, processors of fish, poultry and meat and number of other applications.
Ammonia is manufactured by combining nitrogen and hydrogen directly. Nitrogen and hydrogen are compressed to about 250 atmospheres and heated to about 4000 centigrade. They are then passed over an iron catalyst to form ammonia. The reaction is reversible, and unchanged nitrogen and hydrogen are recycled.