In order to be carried in the chylomicron, retinol (once in the enterocyte) is esterified by lecithin retinol acyl transferase.
All-trans-retinol is referred to as vitamin A, when a fatty acyl group is esterified to the hydroxyl terminus of retinol, a storage form of retinol, the retinyl ester, is formed. In tissues, retinal serves as an intermediate in the synthesis of retinoic acid from retinol.
I believe the choice of Porphyry in the portrait group of tetrarchs speaks to imperial power. Portrait of the Four Tetrarchs is a porphyry sculpture group of four Roman Emperors dating from around 300 AD. The sculptural group has been fixed to a corner of the facade of St mark's Basilica in Vence, Italy since the Middle Ages.
There is no picture , what picture ?
