1. Petroleum refinery process in which large heavy oil molecules are broken down into smaller ones. If conducted only with the application of heat, it is called thermal cracking. If a catalyst is also used, it is called catalytic cracking. If hydrogen is used in addition to heat and catalysts, it is called hydrocracking. 2. Deciphering of a code or encrypted data.
Vitamin D3 is the form of vitamin D called cholecalciferol. Cholecalciferol is the most widely known of the vitamin D series and is a fat soluble vitamin that is stored to some degree in the body. It is used as a dietary supplement and for the treatment and prevention of vitamin D deficiency.
In the liver, cholecalciferol (vitamin D 3) is converted to calcidiol, which is also known as calcifediol (INN), 25-hydroxycholecalciferol (aka 25-hydroxyvitamin D 3 â abbreviated 25(OH)D 3).hether it is made in the skin or ingested, cholecalciferol is hydroxylated in the liver at position 25 (upper right of the molecule) to form 25-hydroxycholecalciferol (calcidiol or 25(OH)D). This reaction is catalyzed by the microsomal enzyme vitamin D 25-hydroxylase, which is produced by hepatocytes.