Photoaging could be induced by accumulated DNA damage on skin cells. Photoaged skin has such characteristics as a nodular leathery surface with fine and coarse wrinkles, blotches and yellowing, dryness, and teleangiectasia, and finally skin cancer formation. For this condition, chemical peeling, iontophoresis, laser and phototherapy are used with some improvement, especially in wrinkles and pigmentary uniformity. Now the mechanisms of these treatments on photoaging have been studied. Glycolic acid may act on skin cells via keratinocytes and activate the cytokine network, which results in the remodeling of tissue construct and elimination of pigment. Heat generated by non-ablative laser or phototherapy might induce heat shock proteins which induce new collagen formation, and eliminate oxidized abnormal materials. This type of research is expected to disclose the cellular and molecular mechanisms of photoaging, and to lead to the establishment of further effective photoaging treatment.

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In this study, a hydrophobic phospholipid polymer nano-dispersion was formed by self-aggregating poly (2-methacryloyloxyethyl phosphorylcholine-co-stearyl methacrylate) (PMS). Self-aggregation was carried out by diluting a PMS/polyol solution with hot water. The zeta potential of the PMS particles was changed by complexation with anionic or cationic surfactants, the addition of which did not affect the average diameter of the PMS particles, which was always less than 50nm. The cationized PMS nano-dispersion was used for treating artificially damaged hair. An X-ray photoelectron spectroscopic analysis showed uniform adsorption of the PMS onto the surface of the hair specimens. The PMS nano-dispersion was not only adsorbed on the surface but also permeated into the hair, as shown by a fluorescence microscopic observation of the damaged hair treated with the PMS nano-dispersion that also contained Nile Red. From a scanning electron microscope observation, the PMS was also found to suppress the lift-ups of the hair cuticle. The surface of damaged hair was hydrophilic, whereas the one treated with PMS was hydrophobic, like healthy hair. PMS treatment has decreased the surface friction and electrostatic decay of damaged hair, and also prevented the discoloration of colored hair.

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It has been reported in recent years that the carbonyl modification of protein plays a part in various diseases. The existence of the protein carbonylation in the stratum corneum also came to be known in the last few years, but the effect on the properties of the stratum corneum including the skin appearance was not clarified. In this study, we examined the influence of protein carbonylation in the stratum corneum to provide helpful information for skin care products focusing on transparency of the stratum corneum. Firstly, we developed a method to assess the protein carbonylation level numerically by the image analysis of tape-stripped stratum corneum reacted with a fluorescent hydrazide. The level of stratum corneum carbonylation of the sun-exposed site (face) was higher than that of unexposed site (upper arm), and the surface part of the stratum corneum showed a higher level of carbonylation compared with the deeper layer. Stratum corneum carbonylation was induced by in vitro UV irradiation. In addition, it was shown that the skin transparency score was significantly low in the woman with high level of protein carbonylation in the stratum corneum of the cheek. An experimentally carbonylated stratum corneum sheet in vitro became opaque. Among the amino acids investigated, L-lysine was the most effective to prevent carbonylation of the stratum corneum ex vivo. Moreover, L-lysine inhibited the decrease in the skin transparency caused by experimental carbonylation of the stratum corneum in the human skin. These results suggest that preventing the carbonylation of the stratum corneum due to adverse effects from the environment by L-lysine could improve the skin transparency.

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In recent years, a lot of people have suffered physical and mental stress. It makes sympathetic nerves dominant, and autonomic nerves unbalanced. Disruption of the balance in autonomic nerves leads to the increase of granulocyte, and causes various undesirable physical conditions. We investigated the relationship between stress and acne in order to confirm the influence of stress on skin conditions. The degree of subjective stress, and the ratio of neutrophils or lymphocytes in leukocytes were measured in acne patients and healthy volunteers. As it is suggested that the increase of the neutrophil ratio by stress makes reactive oxygen, and raises the degree of oxidation in the blood, we also measured the antioxidant action and the degree of oxidative stress by FRAS4. Additionally, the lifestyle characteristics in each group was investigated in order to confirm the relationship with stress by a questionnaire survey. According to the results of the questionnaire survey, acne patients find themselves readily suffering from acne anytime. Compared with healthy volunteers, acne patients have more undesirable lifestyles and higher stress degrees than healthy volunteers. Further, the Biological Antioxidant Potential (BAP), an antioxidant index measured in acne patients, was significantly lower (p<0.0001) than that of healthy volunteers. The acne patients had a higher ratio of neutrophils and a lower ratio of lymphocytes compared to the healthy volunteers. Among the acne patients, the neutrophil ratio was higher in those with high stress (p<0.05). These results suggest that acne patients easily feel higher stress against various loads, and the stress leads to the increase in the neutrophil ratio and the oxidation degree, which exacerbates the acne lesions.

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When fluid is mixed by a rotor and small vessel that has a narrow clearance between its wall and the rotor with the upper part covered by an endplate, the processing fluid becomes a high-speed thin-film spin flow. This flow possibly allows the peripheral speed to be over 30m/s, which was unable to be obtained by a conventional high-speed mixer. As a result, the processing fluid obtains more and homogenous energy. In an actual experiment, we compared a high-speed thin-film spin mixer with a conventional high-speed mixer upon an emulsification experiment with soybean oil. The experiment proved that the former mixer could control the particle size distribution. It also proved that the same result could be obtained by continuous operation as by batch operation. In conclusion, the high-speed thin-film spin mixer can control particle size distribution with a high efficiency.

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A rapid and simple method using gas chromatography (GC) for the determination of diethylene glycol (DEG) in toothpaste was developed. DEG in toothpaste was extracted with methanol containing 1, 4-butanediol as the internal standard by using an ultrasonic bath. The centrifuged and filtrated methanol extracts were analyzed by GC on an InertCap 624 capillary column. The recoveries of DEG from toothpaste fortified at the levels of 0.1, 0.5 and 1.0%, were 103.6, 99.9, 99.4%, respectively. The quantitation limit of DEG in toothpaste was 0.05%. The proposed method could be applied to other cosmetics on the market without any interference. By using this method, DEG was detected the presence in 2 out of 10 toothpaste samples set to the hotel. This analytical method should be useful for quality control for manufacturers and importers of cosmetics.

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