Assessment of Multidimensional Health Care Parameters Among Adults in Japan for Developing a Virtual Human Generative Model: Protocol for a Cross-sectional Study.

Background: Human health status can be measured on the basis of many different parameters. Statistical relationships among these different health parameters will enable several possible health care applications and an approximation of the current health status of individuals, which will allow for more personalized and preventive health care by informing the potential risks and developing personalized interventions. Furthermore, a better understanding of the modifiable risk factors related to lifestyle, diet, and physical activity will facilitate the design of optimal treatment approaches for individuals.

Intrinsic curvature in wool fibres is determined by the relative length of orthocortical and paracortical cells.

Hair curvature underpins structural diversity and function in mammalian coats, but what causes curl in keratin hair fibres? To obtain structural data to determine one aspect of this question, we used confocal microscopy to provide measurements of the two cell types that make up the cortex of merino wool fibres, which was chosen as a well-characterised model system representative of narrow diameter hairs, such as underhairs. We measured orthocortical and paracortical cross-sectional areas, and cortical cell lengths, within individual fibre snippets of defined uniplanar curvature. This allowed a direct test of two long-standing theories of the mechanism of curvature in hairs.

Changes in structure and geometric properties of human hair by aging.

To clarify hair changes by aging, the effect of age on hair properties was investigated from macro- to microscopic view points. Sensory hair luster tests were performed on 230 Japanese females from 10 to 70 years of age, revealing that hair luster decreases with age. The age dependence of the hair diameter and the ellipticity of the hair cross section could not explain luster reduction by aging.

Cortical cell types and intermediate filament arrangements correlate with fiber curvature in Japanese human hair.

Naturally straight and curved human scalp hairs were examined using fluorescence and electron microscopy techniques to determine morphological and ultrastructural features contributing to single fiber curvature. The study excluded cuticle and medulla, which lack known bilateral structural asymmetry and therefore potential to form curved fibers. The cortex contained four classifiable cell types, two of which were always present in much greater abundance than the remaining two types.

Characterization of curved hair of Japanese women with reference to internal structures and amino acid composition.

The variation of hair curvature in Japanese women was quantitatively investigated and the structure of curved hair was characterized with transmission electron microscopy (TEM) and amino acid analysis. Two hundred and thirty Japanese women volunteers, aged from 10 to 70 years, were randomly selected. The evaluation of the volunteers' natural hair shape showed that 53% of Japanese women have straight hair, while the remaining 47% have curved hair (varying from a slightly wavy shape to a frizzy style).

Influence of internal structures of hair fiber on hair appearance. III. Generation of light-scattering factors in hair cuticles and the influence on hair shine.

The effects of thermal treatments on hair fiber induced by blow-drying have been investigated. It was found that the hair shows whitish and powdery appearance after heat drying, especially when dark hair is rapidly dried from a wet condition. For all kinds of hair, the appearance of numerous glittering speckles was confirmed on the cuticle surface by optical microscopic observations.

Influence of internal structure of hair fiber on hair appearance. II. Consideration of the visual perception mechanism of hair appearance.

The optical properties of hair fibers were studied, focusing on the reflections (highlights) from both the front and the back surfaces of the fiber in consideration and on the effect these have on the perceptions of hair appearance. The two reflections are distinguished from each other by sight, because only the back surface reflection is colored by melanin granules and/or dyestuffs inside the fiber. When we observe a flat plate as a model for hair without a cuticle structure, the visual angle between the two light loci correlates with the thickness of the model plate and gives an impression of depth.

Influence of internal structures of hair fiber on hair appearance. I. Light scattering from the porous structure of the medulla of human hair.

In this study the influence of the medulla structure on hair appearance was examined. Hair with a porous medulla gave a whitish and lusterless appearance because of light scattering from the fiber center, whereas in the cases without pores, a clear and brilliant appearance was observed. The optical influences of the medulla pores were measured by a spectral goniophotometer, and obtained data were analyzed in terms of the CIE L*a*b* color system.