Skin depth reduction

Thus, a hair property is the physical phenomena which can change the amounts of photodynamic activation in the epidermis and skin depth. These changes may be related to the number of photons loss. The rate of reduction of the total dose to the delivery light comes from chromophore concentration, melanin of the hair color and skin optical parameters. 

The thickness of any planar shield can be represented in terms of skin depths to indicate the shielding potential of the material. In addition to the absorption over skin depth, significant reduction of the impinging electromagnetic field can occur through reflection from the shield surface. The formula of far-lield reflection loss for plane-wave radiation is given by Eqn (8.26) (Das et al., 2000). 

Nonloaded and loaded SLN were already investigated with respect to use in cosmetics. Although adequate controls are difficult to prepare, first experiments indicate an increase in skin hydration and a reduction in wrinkle depth following SLN application [68]. Moreover, cetyl palmitate-nanodispersions act both as particulate ultraviolet (UV) blockers themselves and as carriers for UV absorbing agents (e.g., 2-hydroxy-4-methoxy benzophenone Eusolex 4360). This results in a threefold... 

The inclusion of ethanol in commercially available transdermal systems has naturally provoked curiosity concerning its role as an enhancer in human skin, particularly in vivo. The mechanism by which ethanol compromises the human stratum comeum in vivo was investigated by Bommannan et al. [125] using ATR-IR in studies analogous to those described previously in this chapter [61 ]. Those in vivo studies on the untreated ventral forearm of healthy adults had revealed a depth-dependent ordering and reduction of the intercellular lipids relative to the superficial layers. Consequently, in the ethanol experiments, the measurement site (about 20 cm ) was tape stripped four times prior to ethanol treatment in order to isolate the effect of ethanol from the inherent lipid changes in untreated SC. The examination site was treated for 30 minutes with absolute ethanol (10 ml) and then spectrally examined periodically over the... 

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