18-MEA and hair appearance.

The effects of the removal of 18-MEA on the dynamic contact angle (advancing contact angle and receding contact angle) and friction force (friction force microscopy (FFM)) were examined in the present study. Chemically untreated hair tresses formed more finely ordered bundles, with the fibers aligned more parallel to each other, in the wet state, and lying flat and aligned parallel to each other in the dry state. Hair tresses in which 18-MEA had been removed by potassium t-butoxide treatment formed coarser tangled bundles and were aligned in a disorderly manner in the wet state, causing the hair to become entangled and disorderly in the dry state. This was because the 18-MEA-removed hair fibers adhered to each other and were not easy to realign in the wet state. The distorted part of the bundle dried faster and the tress shape was eventually fixed in the entangled shape. One role of 18-MEA is to allow hair fibers to lie flat and parallel with respect to each other in the wet state by providing relatively high receding contact angles and low surface friction. Hair alignment in the dry state is directly affected by hair alignment in the wet environment, particularly in the case of damaged hair.

A role of the anteiso branch of 18-MEA in 18-MEA/SPDA to form a persistent hydrophobicity to alkaline-color-treated weathered hair.

The effect of the anteiso-branch moiety of 18-MEA (18-methyleicosanic acid) to create a persistent hydrophobicity of alkaline-color-treated weathered hair treated with 18-MEA/SPDA (stearoxypropyldimethylamine) was investigated by comparing a straight-chain fatty acid (n-heneicosanoic acid, n-HEA) and an iso-branch fatty acid (19-methyleicosanic acid, 19-MEA) with the anteiso-branch fatty acid (18-MEA), using dynamic contact angle measurements, quantification of 18-MEA by LC/MS, and temperature controlled atomic force microscopy (AFM). The dynamic contact angle measurements indicated that the anteiso-branch moiety of 18-MEA is critical for the creation of a persistent hydrophobicity to alkaline-color-treated weathered hair. The temperature-controlled AFM investigations revealed that the anteiso-branch moiety of 18-MEA in the 18-MEA/SPDA system produces a persistent hydrophobicity to alkaline-color-treated weathered hair by providing higher fluidity to the upper region of the 18-MEA/SPDA layer.

Deposition of 18-MEA onto alkaline-color-treated weathered hair to form a persistent hydrophobicity.

A technology for the deposition of a persistent hydrophobicity to alkaline-color-treated weathered hair surfaces using 18-MEA (18-methyleicosanoic acid) is presented. Two approaches were examined in order to make 18-MEA bind tightly to the alkaline-color-treated weathered hair surface. One was to apply 18-MEA as an acid form and the other was to apply 18-MEA as a salt or complex. It was found that the combination of 18-MEA with specific cationic surfactants [stearoxypropyldimethylamine (SPDA) and docosyldimethylamine (DSDA)] makes the alkaline-color-treated weathered hair surface hydrophobic and that its hydrophobicity is maintained even after shampooing. Characterization of adsorbed layers of 18-MEA/SPDA on a mica surface, as a possible hydrophilic surface model, was performed using atomic force microscopy (AFM) and angle-resolved X-ray photoelectron spectroscopy (AR-XPS). The results revealed that 18-MEA/SPDA formed a layer with high wear resistance, with an alkyl chain, the hydrophobic moiety, oriented at an angle of around 25 degrees to the air interface.

MPAI (mass probes aided ionization) method for total analysis of biomolecules by mass spectrometry.

We have designed and synthesized various mass probes, which enable us to effectively ionize various molecules to be detected with mass spectrometry. We call the ionization method using mass probes the "MPAI (mass probes aided ionization)" method. We aim at the sensitive detection of various biological molecules, and also the detection of bio-molecules by a single mass spectrometry serially without changing the mechanical settings. Here, we review mass probes for small molecules with various functional groups and mass probes for proteins. Further, we introduce newly developed mass probes for proteins for highly sensitive detection.

Age-dependent changes in damage processes of hair cuticle.

BACKGROUND: Human hair cuticle is always exposed to various stresses and then gradually lost in daily life. There are two typical patterns of cuticle damage: type L, where the cell membrane complex, the structure located between cuticle cells, is split and the cuticle lifts up, and type E, where the fragile substructure of the cuticle cell (endocuticle) is damaged so that its rugged residue is exposed. We previously reported that type L damage preferentially occurs in the case of Japanese females in their 20s to 40s. AIMS: This study aims to elucidate the age-dependent change of cuticle and its effect on hair properties. METHODS: Hair fibers collected from Japanese females (ranging from 10 to 70 years old) were evaluated in the aspects of inclination for each type of damage, resistance of cuticle against grooming stresses and content of fatty acid 18-MEA on hair surface. RESULTS: It was revealed that the dominant damage pattern shifts from type L to E with aging. Furthermore, the cuticle becomes gradually less resistant to daily grooming stress. The dominance of type E damage accelerates cuticle loss. Reduction of 18-MEA on weathered hair is accelerated with aging on elder hair. CONCLUSIONS: It has been reported that various age-dependent changes of whole hair shaft, such as diameter, density, elasticity, etc., occur in the age range of 40s and 50s. In this study, it was revealed that cuticle becomes more fragile and the hair surface properties deteriorate in the same age range.

Design and synthesis of labeling reagents (MS probes) for highly sensitive electrospray ionization mass spectrometry and their application to the detection of carbonyl, alcohol, carboxylic acid and primary amine samples.

Novel labeling reagents, called MS probes, which possess a positively charged quaternary amine moiety and can transform a neutral analyte into a charged compound by simply mixing with the analyte and allowing the mixture to stand from several minutes to 30 min at room temperature or while heating to 50 degrees C, were designed and synthesized for the highly sensitive detection of carbonyl, alcohol, carboxylic acid and primary amine samples by electrospray ionization mass spectrometry (ESI-MS). The positively charged products can be detected with high sensitivity in an ESI-MS system, which is the most popular liquid MS instrument. All of the labeled products showed a remarkably large increase in the molecular-ion peak abundance detection sensitivity of over 500-fold at picomolar concentration levels compared to that of unlabeled analytes in an ESI-MS system. These MS probes, used together with liquid MS detection, are widely applicable as a convenient method for the highly sensitive detection of less than picomolar levels of analytes, and therefore greatly enhance the power of ESI-MS analysis.