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T Yatagai

Publications and source records attributed to T Yatagai.

10 recordsLinked to original sources
PubMed2002

Experimental and numerical study of the colour appearance of tattoo models.

The colour of tattooed skin has been predicted by a Monte Carlo method based on the optical coefficient spectra of the skin and tattoo dyes. Slices of pig skin, a tattoo phantom and skin phantoms with different thickness were prepared, and their reflectance and transmittance spectra were measured using an integrating sphere at wavelengths varying from 400nm to 700nm. The absorption and scattering coefficient spectra of skin phantoms, pig skins and the tattoo phantom were each calculated using the inverse Monte Carlo method. The skin phantoms and pig skins were overlaid on the tattoo phantom, and the reflectance spectra of the two-layered structures were measured. The reflectance spectra of the two-layered structures were calculated from the optical coefficient spectra using the Monte Carlo method. They agreed well with the measured spectra. The colour differences between the calculated and measured spectra were also evaluated by the L*a*b* colour space distances and showed good agreement, with 3.49 for the skin phantoms and 8.27 for the pig skins.

Animals↗
PubMed2001

Melanin and blood concentration in human skin studied by multiple regression analysis: experiments.

Knowledge of the mechanism of human skin colour and measurement of melanin and blood concentration in human skin are needed in the medical and cosmetic fields. The absorbance spectrum from reflectance at the visible wavelength of human skin increases under several conditions such as a sunburn or scalding. The change of the absorbance spectrum from reflectance including the scattering effect does not correspond to the molar absorption spectrum of melanin and blood. The modified Beer-Lambert law is applied to the change in the absorbance spectrum from reflectance of human skin as the change in melanin and blood is assumed to be small. The concentration of melanin and blood was estimated from the absorbance spectrum reflectance of human skin using multiple regression analysis. Estimated concentrations were compared with the measured one in a phantom experiment and this method was applied to in vivo skin.

Biophysical Phenomena↗
PubMed2001

Melanin and blood concentration in a human skin model studied by multiple regression analysis: assessment by Monte Carlo simulation.

Measurement of melanin and blood concentration in human skin is needed in the medical and the cosmetic fields because human skin colour is mainly determined by the colours of melanin and blood. It is difficult to measure these concentrations in human skin because skin has a multi-layered structure and scatters light strongly throughout the visible spectrum. The Monte Carlo simulation currently used for the analysis of skin colour requires long calculation times and knowledge of the specific optical properties of each skin layer. A regression analysis based on the modified Beer-Lambert law is presented as a method of measuring melanin and blood concentration in human skin in a shorter period of time and with fewer calculations. The accuracy of this method is assessed using Monte Carlo simulations.

Biophysical Phenomena↗
PubMed1999

[Relation between temporomandibular joint disorder and subjective symptoms of fatigue].

An investigation was performed for the purpose of guaging the relation between temporomandibular joint disorder on the one hand and occupational category and subjective symptoms of fatigue on the other. Subjects were 2,414 workers (1,598 male, 816 female) in small and medium size enterprises at 67 workplaces in Hiroshima Prefecture. A comparison of cases with and without temporomandibular joint disorder showed that there were more complaints of fatigue among those with the disorder. Given these indications that temporomandibular joint disorder was related to occupation, it is possible that temporomandibular joint disease may be a work-related disease.

Adult↗
PubMed1998

Activities of optical laboratories 1 and 2 at the Photon Factory.

Recent activities at optical laboratories 1 and 2 at the Photon Factory are presented. The activities are (i) construction of optical laboratory 1, (ii) reconstruction of optical laboratory 2, (iii) construction of a visible synchrotron radiation beam extraction mirror made of beryllium, (iv) small-beam-profile measurement by means of the image restoration method, (v) application of the adaptive optical system for correction of distorted wavefronts caused by deformation of the extraction mirror, (vi) construction of a synchrotron radiation interferometer for investigation of the spatial coherency of the visible synchrotron radiation beam and its application to the measurement of vertical beam profile and size.

Journal Article↗
PubMed1996

[The relation of dental examination results at corporation offices to occupation, subjective symptoms of fatigue and daily lifestyle--an investigation based on the number of missing teeth].

Our investigation was intended to find a relationship between the dental health of labourers and, their jobs, subjective symptoms of fatigue and daily lifestyle. Dentists checked the dental health of 2,565 corporation employees (790 male and 775 female) of small to medium-sized enterprises in Hiroshima prefecture. At the same time they examined the employees' occupation, subjective symptoms of fatigue and their health maintenance behavior according to Breslow's criteria. The data were divided into age groups spanning 10 years. Among males in their 30s, those engaged in transport/driving and engineering/production had more missing teeth than others. We found a relationship between the number of missing teeth and subjective symptoms of fatigue among men in their 30s. This suggests that the greater the number of missing teeth, the greater their subjective symptoms of fatigue. The results suggest that missing teeth cause malocclusion which leads to subjective symptoms of fatigue.

Adult↗
PubMed1989

Changes in microvascular structure of the fibrotic pancreas and their influence on pancreatic endocrine function.

The objectives of this study were to clarify the microvascular structure in and around the Langerhans' islands of the normal pancreas, elucidate how the structure changes with advance of pancreatic fibrosis owing to stagnation of pancreatic juice, and how these changes influence the endocrine function of the pancreas. For these purposes, the changes in microvascular structure of the fibrotic pancreas, produced by ligation of the pancreatic duct in mongrel adult dogs, were investigated by microangiography and injection replica scanning electron microscopic methods. In addition, the endocrine function of the pancreas was studied by the intravenous (iv) glucose tolerance test. The results revealed that the basic blood vessel structure of the Langerhans' islands, and its insulin secretory function, were maintained relatively well in the long-term, duct-ligated pancreas though the capillary network spreading in the pancreatic exocrine part could hardly be observed.

Animals↗