<P> A recent report demonstrated that 50 mg of β - carotene every other day prevented cognitive decline in a study of over 4000 physicians at a mean treatment duration of 18 years . </P> <P> Oral β - carotene is prescribed to people suffering from erythropoietic protoporphyria . It provides them some relief from photosensitivity . </P> <P> Carotenemia or hypercarotenemia is excess carotene, but unlike excess vitamin A, carotene is non-toxic . Although hypercarotenemia is not particularly dangerous, it can lead to an oranging of the skin (carotenodermia), but not the conjunctiva of eyes (thus easily distinguishing it visually from jaundice). It is most commonly associated with consumption of an abundance of carrots, but it also can be a medical sign of more dangerous conditions . </P> <P> β - Carotene and lycopene molecules can be encapsulated into carbon nanotubes enhancing the optical properties of carbon nanotubes . Efficient energy transfer occurs between the encapsulated dye and nanotube--light is absorbed by the dye and without significant loss is transferred to the single wall carbon nanotube (SWCNT). Encapsulation increases chemical and thermal stability of carotene molecules; it also allows their isolation and individual characterization . </P>

Where is carotene found in a plant cell