Up to date, no worldwide standard in vitro method has been established for the determination of the sun protection factor (SPF), since there are many problems in terms of its repeatability and reliability. Here, we have studied the problems on the in vitro SPF measurements brought about by the phenomenon called viscous fingering. A spatially periodic stripe pattern is usually formed spontaneously when a viscous fluid is applied onto a solid substrate. For the in vitro SPF measurements, the recommended amount of sunscreen is applied onto a substrate, and the intensity of the transmitted UV light through the sunscreen layer is evaluated. Our theoretical analysis indicated that the nonuniformity of the thickness of the sunscreen layer varied the net UV absorbance. Pseudo-sunscreen composites having no phase separation structures were prepared and applied on a quartz plate for the measurements of the UV absorbance. Two types of applicators, a block applicator and a 4-sided applicator were used. The flat surface was always obtained when the 4-sided applicator was used, while the spatially periodic stripe pattern was always generated spontaneously when the block applicator was used. The net UV absorbance of the layer on which the stripe pattern was formed was found to be lower than that of the flat layer having the same average thickness. Theoretical simulations quantitatively reproduced the variation of the net UV absorbance led by the change of the geometry of the layer. The results of this study propose the definite necessity of strict regulations on the coating method of sunscreens for the establishment of the in vitro SPF test method.

When undergoing power bench press against medium-light resistances, maximum ballistic actions are important strategies for improving 1RM and shot put performance of university shot-putters.

Water-repellent and self-cleaning properties of lotus leaves are considered to be due to its double roughness structure, protrusion structure (approximately 20 microm) and hairy structure (0.2-1.0 microm). In this study, attempts to fabricate a spatially periodic double roughness structure by two far-from-equilibrium self-organization phenomena, a directional viscous fingering and a spinodal dewetting, were made. A mixture of an octylsilyl titanium dioxide particle having an average diameter of 35 nm suspended in volatile silicone, decamethyl cyclopentasiloxane, and octyl p-methoxycinnamate was spread on a glass plate by dragging an applicator across the top. Formation of a stripe pattern parallel to the direction of dragging, called directional viscous fingering, was sometimes observed. Influences of spreading conditions on the pattern formation were analyzed. In addition, attempts were made to apply the stripe pattern formation to the preparation of a water repellent surface. We have succeeded in preparing a highly water-repellent surface by immersing a glass plate, on which a spatially periodic stripe pattern having a characteristic wavelength of 200-700 microm was formed, in water, after the completion of evaporation of decamethyl cyclopentasiloxane. In this case, dewetting patterns having a characteristic wavelength at around 5 microm were formed at the bottom part of the stripe patterns. Neither the surface on which only the mesoscopic spatially periodic stripe pattern was formed nor the one on which only the microscopic dewetting pattern was formed showed high water-repellent properties, indicating that the coexistence of the two different scales of patterns increased the water-repellent properties of the hydrophobic surface.

No abstract

The C-6 hydroxymethyl group of methyl d-galactopyranoside and oligosaccharides containing d-galactopyranosyl residues were found to be oxidized with oxygen by galactose oxidase to the corresponding carboxyl group via an aldehyde intermediate.