Specifically, the group of nine carbon atoms at each end form a β-ring. The α-carotene molecule has a β-ring at one end; the other end is called an ε-ring. There is no such thing as an "α-ring". These and similar names for the ends of the carotenoid molecules form the basis of a systematic naming scheme, according to which:

α-carotene is β,ε-carotene;
β-carotene is β,β-carotene;
γ-carotene (with one β ring and one uncyclized end that is labelled psi) is β,ψ-carotene;
δ-carotene (with one ε ring and one uncyclized end) is ε,ψ-carotene;
ε-carotene is ε,ε-carotene
lycopene is ψ,ψ-caroteneζ-Carotene is the biosynthetic precursor of neurosporene, which is the precursor of lycopene, which, in turn, is the precursor of the carotenes α through ε. Food additive
Carotene is used to colour products such as juice, cakes, desserts, butter and margarine. It is approved for use as a food additive in the EU (listed as additive E160a) Australia and New Zealand (listed as 160a) and the US. See also
Antioxidant

References
External links
Carotene at the US National Library of Medicine Medical Subject Headings (MeSH)
Acroosteolysis is resorption of the distal bony phalanges. Acroosteolysis has two patterns of resorption in adults:  diffuse and bandlike. The diffuse pattern of resorption has a widely diverse differential diagnosis which includes:  pyknodysostosis, collagen vascular disease and vasculitis, Raynauds neuropathy, trauma, epidermolysis bullosa, psoriasis, frostbite, sarcoidosis, hypertrophic osteoarthropathy, acromegaly, and advanced leprosy.The bandlike pattern of resorption may be seen with polyvinyl chloride exposure and Hadju-Cheney syndrome.A mnemonic commonly used for acro-osteolysis is PINCHFO.Pyknodysostosis, Psoriasis,
Injury (thermal burn, frostbite),
Neuropathy (diabetes),
Collagen vascular disease (scleroderma, Raynauds),
Hyperparathyroidism,
Familial (Hadju-Cheney, progeria), 
Occupational (polyvinyl exposure),
Acroosteolysis may be associated with minimal skin changes or with ischemic skin lesions that may result in digital necrosis. : 665

See also
Nail anatomy


== References ==