Eiko Hatakeyama

Effects of Cross-sectional Area on Human Bite Studied with Raw Carrot and Surimi Gel

The effects of the cross-sectional area of food samples on bite force with molar teeth were investigated using raw carrots and surimi gels. We evaluated human bite force for food samples with different sizes between the upper and lower molars using a multiple-point sheet sensor and electromyography (EMG). The bite force curve and EMG clearly showed textural characteristics of the carrot and gel. In particular, the first peak in the bite curves corresponded to breaking point in the compression test. With increasing cross-sectional area of both foodstuffs, the bite force and contact area increased and the average stress to which the specimen was subjected (mean stress) tended to decrease, while the stress produced between the teeth and the specimen (active stress) did not change. Chewing rhythm and EMG activities were not greatly influenced by sample size. These findings suggest that higher bite force might cause difficulty in biting food with a larger cross-sectional area.

Adenosine, an Identified Active Component from the Driselase-Treated Fraction of Rice Bran, Is Effective at Improving Metabolic Syndrome in Stroke-Prone Spontaneously Hypertensive Rats

In the present study, we isolated and identified an active component from the Driselase-treated fraction and investigated its effect by acute and chronic oral administration on hypertension, lipid, and glucose metabolism in stroke-prone spontaneously hypertensive rats. The active component was identified as adenosine and improves hypertension after single oral administration. Rats who were 10 weeks old were divided into control and adenosine groups and were administered water or water with adenosine (10 mg/L), respectively, for 3 weeks. Hypertension and plasma lipid, nitric oxide, insulin, leptin, adiponectin levels, and glucose metabolism were significantly improved in the adenosine group. The mRNA expression levels of genes involved in lipid and glucose metabolism were altered in the adenosine group. Single oral administration of adenosine (10 mg/kg body weight) improved hypertension and plasma triglyceride, glucose, and nitric oxide levels 2 h after administration. In conclusion, oral acute and chronic administration of adenosine are beneficial and improve the metabolic syndrome-related disease parameters.

Knowledge Discovery from fMRI Brain Images by Logical Regression Analysis

This paper presents knowledge discovery from fMRI brain images. The algorithm for the discovery is the Logical Regression Analysis, which consists of two steps. The first step is regression analysis. The second step is rule extraction from the regression formula obtained by the regression analysis. In this paper, we use nonparametric regression analysis as a regression analysis, since there are not sufficient data in knowledge discovery from fMRI brain images. The algorithm has been applied to two experimental tasks, finger tapping and calculation. Experimental results show that the algorithm has rediscovered well-known facts and discovered new facts.