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.
Some organic foods may be healthier than their processed counterparts. Organic foods are grown or raised without chemical pesticides, antibiotics or hormones, according to the U.S. Department of Agriculture.Organic farmers take advantage of natural methods of fertilizing soil and controlling weeds and insects.Certain organic foods, such as milk and tomatoes, may contain health benefits that make these organic foods a healthier choice than their processed or conventional counterparts.rganic farmers take advantage of natural methods of fertilizing soil and controlling weeds and insects. Certain organic foods, such as milk and tomatoes, may contain health benefits that make these organic foods a healthier choice than their processed or conventional counterparts.