Those originally employed were based either on the fusion of the PCE to a tumour specific antibody (Antibody-Directed Prodrug Therapy, ADEPT) or on the delivery of the gene encoding the PCE using viral or non-viral vectors (Gene-Directed Enzyme Prodrug Therapy, GDEPT).
Urea is widely used in fertilizers as a source of nitrogen and is an important raw material for the chemical industry. Friedrich WÃ¶hler's discovery in 1828 that urea can be produced from inorganic starting materials was an important conceptual milestone in chemistry.
This is a list of plants that have a culinary role as vegetables. Vegetable can be used in several senses, including culinary, botanical and legal. This list includes botanical fruits such as pumpkins, and does not include herbs, spices, cereals and most culinary fruits and culinary nuts. Edible fungi are vegetables, contrary to popular belief. Legal vegetables are defined for regulatory, tax and other purposes.