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The principal natural stereoisomer of lutein is (3R,3 ′ R,6 ′ R)-beta,epsilon-carotene-3,3 ′-diol. Lutein is a lipophilic molecule and is generally insoluble in water. The presence of the long chromophore of conjugated double bonds (polyene chain) provides the distinctive light-absorbing properties. The polyene chain is susceptible to ...
In plants, the xanthophyll lutein is the most abundant carotenoid and its role in preventing age-related eye disease is currently under investigation. [5] Lutein and the other carotenoid pigments found in mature leaves are often not obvious because of the masking presence of chlorophyll. When chlorophyll is not present, as in autumn foliage ...
Viscosity - Chain entanglements are very important in viscous flow behavior of polymers. As the chain becomes longer, chain mobility decreases; that is, the chains become more entangled with each other. Glass-transition temperature - An increase in chain length often leads to an increase in the glass-transition temperature, T g. The increased ...
It absorbs blue and green light at bandwidth 450-540 nm, imparting a brownish-olive color to algae. Fucoxanthin has a highly unique structure that contains both an epoxide bond and hydroxyl groups along with an allenic bond (two adjacent carbon-carbon double bonds) and a conjugated carbonyl group (carbon-oxygen double bond) in the polyene chain ...
Some polyenes are brightly colored, an otherwise rare property for a hydrocarbon. Normally alkenes absorb in the ultraviolet region of a spectrum, but the absorption energy state of polyenes with numerous conjugated double bonds can be lowered such that they enter the visible region of the spectrum, resulting in compounds which are coloured (because they contain a chromophore).
The basic structure of the hydrophobic retinoid molecule consists of a cyclic end group, a polyene side chain and a polar end group. The conjugated system formed by alternating C=C double bonds in the polyene side chain are responsible for the color of retinoids (typically yellow, orange, or red).
But there is reason to believe (e.g., neutron diffraction studies) that excluded volume effects may cancel out, so that, under certain conditions, chain dimensions in amorphous polymers have approximately the ideal, calculated size [3] When separate chains interact cooperatively, as in forming crystalline regions in solid thermoplastics, a ...
R is some length scale describing the chain conformation such as the radius of gyration or root-mean-square end-to-end distance of the chain. [2] Typically the pervaded volume is very large relative to the space actually occupied by the chain as most of the pervaded volume is usually filled with solvent or other chains. [1]