Motoharu Takao

PHOTOPERIOD AT BIRTH DOES NOT MODULATE THE DIURNAL PREFERENCE IN ASIAN POPULATION

Two research groups reported that diurnal preference in Canadian and South European populations was modulated by the season of birth. The aim of the present study was to examine this association in the Japanese population. In this study, 1156 college students were administered the Morningness-Eveningness Questionnaire and asked the date and place of birth. Our results demonstrated that neither photoperiod nor season of birth modulated diurnal preference in the Japanese population. Two biological differences are reported to exist between Caucasians and Asians: polymorphisms of circadian clock genes and difference in ocular photosensitivity. These ethnic differences might characterize the circadian photosensitivity in infancy. (Author correspondence: takao@keyaki.cc.u-tokai.ac.jp).

An Optical Halitosis (Bad Breath) Sensor with Mao-A

Methyl mercaptan (MM: CH3SH) is known as one of major chemicals of halitosis (bad breath). Monoamine oxidase type-A (MAO-A) has been reported to catalyze the oxidation of methyl mercaptan for a xenobiotic metabolism in human liver. In this research, an oxygen sensitive optical fiber was applied for developing a optical bio-sniffer for methyl mercaptan in halitosis. An optical bio-sniffer was constructed by applying an MAO-A immobilized membrane onto the fiber-tip with a tube-ring. The optical device was possible to detect the oxygen consumption induced by MAO-A enzymatic reaction with methyl mercaptan as an index of halitosis level. As the result of the physiological application, the bio-sniffer could be successfully used the halitosis monitoring.

Health Effects of Occupational Exposure to LED Light: A Special Reference to Plant Cultivation Works in Plant Factories

Light-emitting diode (LED) is one of the greatest inventions that changed plant production practices in the plant factories. Two main advantages of LED lighting are high-energy efficiency and arbitrary controllability of spectral design. In spite of the rapid advancements in LED lighting technology, workability and occupational health are not considered during plant factory design. In this chapter, I depict the impaired workability and the possible health problems associated with LED lighting. Plant utilizes blue light (BL) for photosynthesis, while BL may cause serious chronic diseases such as diabetes mellitus and breast cancer in humans by abnormal regulation of the human circadian rhythm. High-intensity BL also damages the lens and retina of the human eye, resulting in chronic visual impairment. The germicidal UV-C light causes severe chronic eye diseases in the laborers. Glare from the luminaires reduces visual performance and visibility, resulting in decrease of the laborers’ productivity. The possible improvements that can be made to regulate the lighting environment will be discussed with special reference to the plant factories and the greenhouses with luminaires. Regulation of the lighting in the working environment will improve feasibility and comfort as well as raise productivity and health of the laborers.

Diurnal modulation of visual motion prediction

Predicting the future position of moving objects is an essential cognitive function used for many daily activities, such as driving, walking and reaching. The experiments described in this paper show a marked diurnal modulation of motion prediction in inflating image perception. This motion prediction was shown to be more accurate in the afternoon than in the morning. In contrast, such modulation could not be found in deflating image perception. Such diurnal fluctuations may be mediated by circadian properties of retinal cone photoreceptors.

Bio-sniffers with enzyme for breath analysis after drinking

Two kinds of bioelectronic gas-sensors (bio-sniffers) with alcohol oxidase (AOD) and aldehyde dehydrogenase (ALDH) were developed for convenient analysis of ethanol and acetaldehyde in expired gas, respectively. The AOD and ALDH bio-sniffer devices were possible to monitor the concentrations of alcohol and acetaldehyde in the expired gas after drinking, and would be provide the assessment of the alcohol metabolizing level and identify ALDH-activation in the subject non-invasively.