It is a common experience that a makeup which forms a smooth, continuous film when applied on one person may form uneven, unattractive film on another subject. Formulating makeup which can provide perfectly uniform film, regardless the skin condition, remains an unanswered challenge to cosmetic formulators.
The purpose of this study was to investigate the reasons for the above difference and to find relationships between the uniformity of the film and the physical properties of the makeup foundation ingredients and the effects of microstructure of the skin surface.
Factor analysis of the experimental data indicated that the uniformity of the foundation film had most significant relationship with the evenness of the relief pattern shown by the skin surface replica. Three-dimensional measurements of the replica by a surface roughness meter established that the evenness of the rising portions of the skin surface was the main controlling factor in determining the uniformity of the film.
Relationship between the uniformity of the applied film and physical properties of the powder were investigated by determining the uniformity of the powder film applied on the skin or a positive replica. Reduction of the particle size of the powder and prevention of agglomeration were found to promote forming uniform films. A new surface treatment technique by fluoride coating effectively reduced surface activity of the powder, reduced the particle size and eliminated agglomeration. Using this technique and information from this research, we developed a novel makeup which proved to form very uniform film even on uneven skin surface.

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The interaction between stearyltrimethylammonium chloride (STAC) and sodium N-lauroyl-N-metyl-beta-alanine (NaLMA) has been investigated by viscosity, phase diagram, conductivity and phase inversion temperature techniques. The solution properties of the NaLMA-STAC mixture indicate the formation of hydrophobic ion-pairs between NaLMA and STAG. It has been demonstrated that the NaLMA-STAC mixture is water soluble over a wide temperature range because of its low Krafft point and exhibits cloud point behavior similar to that of polyoxyetylenated nonionic surfactants. In addition, the NaLMA-STAC mixture shows a weak interaction with proteins.
The hydrophobic nature of these ion-pairs is effective for the sorption by hair and for the lowering of the coefficient of friction of the hair. It has been shown that the use of anionic cationic mixed conditioners makes it possible to formulate a newtype of conditioning shampoo (all-in-one shampoo and conditioner) which sufficiently decreases the friction of the hair and suppresses the electrostatic charge generated by combing.

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The most important hair colorants on the market are the oxidation dyes because of their effective coloring. They consist of primary intermediates, oxidants, and couplers. In most cases, hydrogen peroxide is employed as the oxidants, but it has resulted in damage to hair. Therefore, there has been much hope of finding a better and safer hair colorant. In our studies, we have found a hair colorant in which the primary intermediates are oxidized in the presence of silver ions used as a catalyst without hydrogen peroxide.
In order to dye hair, oxidation of the intermediates must take place within the hair. If the oxidative reaction is completed outside of the hair strand, the enlarged dye molecules will not diffuse within the hair strand. If the reaction proceeds slowly, it is too time-consuming for hair coloring. We have succeeded in controlling the elution rate of silver ion catalyzing the oxidation reaction by holding it within the zeolite. By controlling the contents of silver in zeolite, the contents of the silver-zeolite in dyeing system, and the composition of the solvent, the elution rate can be best controlled for dyeing the hair.
The hair coloring products using silver-zeolite as an oxidation catalyst were shown to be safer in the mutagenicity tests which we have conducted. We have also found less damage of the dyed hair surface than with conventional hair deys using hydrogen peroxide.

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To study the effects cosmetic materials on normal human keratinocyte (NHK) differentiation, we investigated the evaluation method of differentiation in NHK.
Involucrin is a precurser protein of detergent-insoluble cornified envelope and a marker of terminal differentiation of epidermal keratinocytes. To quantify differentiation of NHK, the population of involucrin-positive cells was estimated by immunofluorescent staining using antiinvolucrin antibody and flow cytometry. NHK were cultured under three conditions: 0.1mM Ca²⁺, 1.8mM Ca²⁺, and 1.8mM Ca²⁺ with 10% fetal calf serum (FCS). The population of in volucrin-positive cells increased from 8.0% to 22.1% (2.8 fold) in case of 1.8mM Ca²⁺, and to 37.1% (4.6 fold) with addition of FCS. In addition, the rate of involucrin-positive cells was correlated significantly with the production rate of cornified envelope under the same condition.
The cytofluorographic analysis of involucrin expression made it possible to determine the number of differentiated cells precisely and reliably in a large number of samples. Thus, the method described here seems to be a useful method for evaluation of keratinocyte differentiation.

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This paper reports the relationships between various parameters obtained from measurements on scalp skin, hair follicle and hair shaft in young females (13-28 years old, n=37).
Parameters measured are; (1) sebum contents (2) surface temperature (3) water contents (4) stratum corneum cell area, as to scalp skn; (5) glucose-6-phosphate dehydrogenas (G6PDH) (6) transglutaminase (TGase), as to hair follicle enzyme activities; and (7) cross-sectioned area (8) cuticle scale edge pattern (9) tensile strength (10) limiting extension (11) frictional coefficient (12) amino acid composition (13) cystine contents (14) polar lipids contents (cholesterol sulphate and ceramides) (15) contents of trace elements (Mg, K, Ca, Fe, Cu, Zn), as to hair shaft. The effects of hair care customs and hair treatments on the chemical and physical properties of hair were also investigated.
As the results from statistical analysis of these various parameters, a positive correlation (p<0.001) between hair follicle G6PDH and cross-sectioned area of hair shaft, and a negative correlation (p<0.01) between G6PDH and cuticle scale edge pattern were elucidated. These facts suggest that G6PDH plays an important role in a formation of hair follicle size and structure as a reflection of mitotic activity. Another negative correlation (p<0.01) between frictional coefficient and TGase was detected, and this enzyme seemed to participate in the hardening of cuticular structures.
Relationship between parameters for scalp skin and physico-chemical properties of hair shaft was not clear.
Permanent waving of hair appeared to decrease cystine content, water content of hair tip, and to increase Mg and Ca contents. This implies the damaging of hair shaft caused by hair treatment.

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