“…Jasinghe et al investigated the kinetics of this conversion but focused on treatment parameters (time, temperature and moisture content) and only measured D 2 production (Jasinghe et al, 2007). The kinetics of this reaction has been studied in model systems (Terenetskaya, Bogoslovskii, Vysotskii, & Luknitskii, 1994) in the case of the D 3 series in human skin (Holick et al, 1981;MacLaughlin, Anderson, & Holick, 1982;Tian, Chen, Matsuoka, Wortsman, & Holick, 1993), lizard skin (Holick, Tian, & Allen, 1995) and liposomes (Tian & Holick, 1999). In most cases, the production of the photoproducts is nonlinear with respect to dose.…”