Provitamin D2 and Provitamin D3 Photo Transformations in Cholesteric Liquid Crystal Mixtures Induced by UV Radiation

Shifts of selective reflection peaks under UV irradiation (which can be observed as color changes) are reported for induced cholesteric systems (nematic + optically active dopant) additionally doped with ergosterol (provitamin D 2 ) or 7-dehydrocholesterol (provitamin D 3 ). the effect is based on t...

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Bibliographic Details
Published inMolecular crystals and liquid crystals (Philadelphia, Pa. : 2003) Vol. 433; no. 1; pp. 73 - 85
Main Authors Chilaya, G., Petriashvili, G., Chanishvili, A., Terenetskaya, I., Kireeva, N., Lisetski, L.
Format Journal Article
LanguageEnglish
Published Taylor & Francis Group 01.06.2005
Subjects
induced cholesteric
phototransformation
provitamin D
UV monitoring
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Summary:Shifts of selective reflection peaks under UV irradiation (which can be observed as color changes) are reported for induced cholesteric systems (nematic + optically active dopant) additionally doped with ergosterol (provitamin D 2 ) or 7-dehydrocholesterol (provitamin D 3 ). the effect is based on the photoinduced conversion of ergosterol into vitamin D 2 , and 7-dehydrocholesterol into vitamin D 3 , with the vitamins and provitamins having opposite signs of their helical twisting power. The observed shifts of the selective reflection peaks (more than 190 nm after 45 min of UV irradiation) allow both instrumental and visual monitoring of biologically active UV radiation.
ISSN:1542-1406
1563-5287
DOI:10.1080/15421400590956243