No abstract

The skin's uppermost thin layer, stratum corneum, plays a crucial role in protecting the body against unwanted influences from the environment. Disruption of the stratum corneum, by tape stripping or chemical injury, results in epidermal recovery of the skin barrier. Soy phytosterols are widely used in the cosmetic field as active ingredients in creams and lipsticks. Furthermore, they deserve an important place among nutracosmeceuticals; in fact, after their absorption from the diet they are transferred from the plasma to the skin, playing an important role in the constitution of skin surface lipids. The aim of the present work was to study the effect of the topical application of soybean phytosterols on skin barrier recovery in human volunteers using the extent of methyl nicotinate (MN)induced erythema in damaged skin as a parameter to evaluate the rate of stratum corneum recovery. MN was chosen as an erythematogenous substance for its capability to cause an erythema whose intensity and duration are proportional to the quantity of the substance that has entered the living epidermis over time. MN-induced erythema was monitored using reflectance spectrophotometry as a non-invasive instrumental technique. The results show clearly that soy phytosterols exert positive results on skin repair; in fact, 3 days after tape stripping, the sites treated with a formulation containing phytosterols showed an appreciable recovery of barrier function compared to those treated with a vehicle control without soy phytosterols.

Relative grain‐boundary sliding at the surface of a three‐phase superplastic ceramic after compressive deformation was measured using atomic force microscopy and scanning electron microscopy to investigate the x, y, and z strain contributions at different types of grain boundaries. This alumina (40 vol%), zirconia (30 vol%), and mullite (30 vol%) composite had an average grain size of 260 nm. The composite was deformed in compression under constant stress conditions in sequential increments of 5%–10% true strain at 1350°C. Six different types of grain boundaries (alumina/alumina, zirconia/zirconia, mullite/mullite, alumina/zirconia, alumina/mullite, and zirconia/mullite) were characterized, for over 800 boundaries in all. It was found that all types of boundaries contributed significantly to the overall deformation with no differentiation between grain boundaries of the same phase and grain boundaries of dissimilar phases, with the exception of mullite/mullite boundaries that had a more complex surface topology due to the in situ formation of mullite during sintering.