The reason why we can sense odor is the existence of odor molecules. We distinguish many kinds of odors because odor receptors recognize various structural changes of odor molecules. We experience a variety of odors though the kind of receptors is only about 400. Furthermore, the odors of many materials are composed of a large number of odor ingredients. Understanding of the complicated odor recognition mechanism is necessary for knowing how the odor of a material is made from the odor characteristics of individual odor molecules. Knowledge about what kinds of change in the structure of those molecules can be captured by the receptors is necessary for understanding the reception mechanism. From the analysis of the properties of fragrances such as a sandalwood or frankincense, which are representative incense materials, it was shown that the coexistence of odor molecules with a similar structure is important to the expression of the fragrance characteristic of the material. Research into the structure-odor relationships of odor molecules such as santalol or anethole was done to obtain information on what kind of structure of odor molecules can be recognized.

There are bacteria that cannot be seen by the naked eye on human skin. A predominance of Staphylococcus genus in the skin microbiota is known to worsen atopic dermatitis, indicating a relationship between the ratio or diversity of the skin microbiota and the skin condition. However, the skin is homeostatic and the specific bacterial ratio rarely changes in healthy individuals. We hypothesized that not only the ratio, but also the number of bacteria, can affect the skin condition. In this study, we collected skin microbes from the cheeks of 269 women, and determined the total number of bacteria per unit of skin area by performing quantitative polymerase chain reaction targeting the bacterial Tu（tuf）gene. We analyzed the relationship between the number of bacteria and various scores of skin conditions. Significant differences were found between the group with a high bacterial count and the group with a low bacterial count, i.e., the amount of sebum, pore count, texture count, dermis thickness, and redness level were higher in the high bacterial count group than in the low bacterial count group. These results suggest the possibility that the number of bacteria affects the skin condition. Thus, the total number of bacteria should also be examined when analyzing the relationship between the skin microbiota and the skin condition.

This study aims to innovate shampoos themselves and their uses, to be environmentally friendly. We aimed to develop a transparent shampoo that does not have hair treatment agents and has a high conditioning effect with shampoo alone. We focused on the coacervation of shampoo and devised a method to incorporate a large amount of oil components into the coacervate. First, to incorporate a large amount of oil components in water-based shampoo transparently, we screened several anionic surfactants and selected MIPA-C12-14 sec-alketh-3 acetate (MIPA-C12-14), which had high foamability and compatibility with oil components. Second, the solubilizing ability for various oil components of the shampoo containing MIPA-C12-14 was confirmed. Finally, the newly developed oil-in-shampoo formulation and a typical hair treatment, each containing 5% amodimethicone as an oil component, were applied on damaged hair, and the distribution of the mass% of Si element from amodimethicone, adsorbed on the hair surface, was analyzed by SEMEDX. We confirmed that the newly developed oil-in-shampoo formulation had a higher distribution of Si element on the hair surface than a typical hair treatment. In addition, the frictional coefficient( MIU) of the hair surface was measured using a frictional analyzer, and it was confirmed that the newly developed oil-in-shampoo formulation yielded similar smoothness as a typical hair treatment. The newly developed shampoo will hopefully contribute to the creation of shampoos with the added value of high conditioning.

The desire for makeup foundations to provide good coverage and a natural appearance has been a long-standing challenge. This is due, in part, to the fact that makeup layers are primarily composed of pigments with a high refractive index. As a result, these pigments predominantly scatter the incident light on their uneven surfaces, inhibiting light absorption inside the makeup layer. This exchange for the coverage effect can lead to a deterioration of optical properties such as gloss and color, which are important for achieving a natural look. The result can be an unnatural, matte, or pale appearance. To achieve both coverage and naturalness, it is necessary to control the state of pigments within the makeup layer to keep them dispersed. In this study, we developed a novel W/O emulsifying technology that utilizes an amphiphilic polymer and two types of nonionic surfactants. The newly developed W/O emulsion organizes the makeup layer with highly dispersed pigments inside the amphiphilic polymer networks, resulting in improved coverage and naturalness with enhanced gloss and color.

The bleached hair tends to get tangled at the time of shampooing which leads it to frizz and spread from the root after drying. In order to elucidate the mechanism of frizz formation in bleached hair, we first attempted to reproduce the frizz phenomenon and examined the causal relationship between the basic physical properties of bleached hair and the frizz phenomenon, as well as the detailed internal structure of the frizz area. Bleached hair possesses the following characteristics when compared with untreated hair and colored hair. 1) Water easily spreads over the surface of the hair, making it more highly hydrophilic. 2) Water swelling is higher. 3) The elastic modulus and strength in water are low, and the recovery from deformation is also low (high residual strain is present). 4)There is little difference in elastic modulus and strength in the dry state, but recovery from deformation is low( high residual strain is present). The characteristics of bleached hair 1), 2), and 3) are factors that increase tangling by causing hairs to adhere to each other during shampooing. The characteristic 4) of bleached hair is the main factor that immobilizes the deformation generated as the entangled intersections are pulled during drying. Small-angle x-ray scattering experiments also revealed that the immobilized denatured structure is mainly due to the stretching and thinning of the intermediate filament associated proteins (IFAP) in cortex cells by pulling the intersections of the tangled bleached hair.

Clogged pores are one of the top skin concerns for women, as they cause pores to look conspicuous and rough, which leads to dull skin around the pores and lackluster facial skin. In our previous study, we had conducted a continuous use test of cleansing oils for the purpose of removing keratotic plugs and had found that cleansing oil containing polyglycerol fatty acid esters (PGFE) is effective in reducing the size of keratotic plugs and the level of carbonylated proteins (CP) in stratum corneum around the pores. Keratotic plugs are substances composed of sebum and keratin-based proteins. In this study, we focused on the constituent sebum and compared the effectiveness of PGFE in cleansing oil with one of the polyethylene glycol-type surfactants (PEG). Consequently, it is confirmed that PGFE has better compatibility with sebum than PEG, and is highly effective in lowering the melting point of sebum, and these properties are considered to be related to the mechanism by which cleansing oils containing PGFE reduce the size of keratotic plugs.