Rahula Janiš

Preparation of 1‐monoacyIgIyceroIs from gIycidoI and fatty acids cataIyzed by the chromium(III)‐fatty acid system

A description is given for preparing 1-monoacylglycerols by the reaction of fatty acids with glycidol catalyzed by Cr(III)-fatty acid complexes. These complexes were found to possess catalytic efficiency substantially greater than catalysts employed earlier. Effects of catalyst type, its content in the mixture, molar ratio of reactants, and reaction temperature during the course of acid conversion were studied. With a catalyst content of 0.5% by mass of charged reactants and at 90 °C a 90— 95% conversion of the acid can be achieved within 60 min. In addition to the corresponding 1-monoacylglycerol, only unreacted starting substances and the catalyst were detected in resulting reaction mixtures.

Comparison of metrological techniques for evaluation of the impact of a cosmetic product containing hyaluronic acid on the properties of skin surface

The aim of this research was to evaluate mutual interchangeability of four principally different biometric instrumental techniques designed for objective measurement of changes in the physical, mechanical, and topographical properties of the skin surface treated with commercial antiaging cosmetic products with hyaluronic acid. The following instrumental devices were used: Visioscope PC 35, Corneometer Multiprobe Adapter MPA 6, Reviscometer RVM 600, and 3D scanner Talysurf CLI 500. The comparison of the individual methods was performed using cluster analysis. The study involved 25 female volunteers aged 40-65. Measurements were taken before and after 30 daily in vivo applications of an antiaging preparation to the skin surface in the periorbital area. A slight reduction in skin surface roughness was recorded in 55% of the volunteers. On the contrary, a worsening from their initial states was detected in 25% of the subjects, while for 20%, no significant change was reported. Cluster analysis confirmed that the mentioned methodologies can be divided into two basic clusters, namely, a cluster of methods recording the changes in skin relief by means of optical techniques, and a cluster of methods investigating changes in hydration and anisotropy. In practice, the techniques in different clusters are not interchangeable and should be assessed separately.

Objective measurements of skin surface roughness after microdermabrasion treatment

The aim of this article is to present a new methodology for assessment of skin topology using a three‐dimensional image (3D).