Toru Yukimasa

The possibility of the deterioration of autonomic nerve activity in depression

Patients with depression are often troubled by various physical symptoms as well as feelings of dejection. Some of the physical symptoms are related to the autonomic nervous system. In this study, we tried to estimate the activity of the autonomic nerves in depression by measuring motor activity and R-R interval. Our results suggest that the activity of the sympathetic nerves is higher and that of the vagal nerves system is lower in depressive state.

Precise analysis of head deformation at falling shock

Accurate evaluation of fall accidents is very important. We have done the experiment in JARI using human-type robot which simulates the human accidental injury. The precise data of acceleration has been taken from the robot. Using the acceleration data, the motion of the head center is derived. The speed and the position of the head center are determined under a realistic condition. The deformation of head surface is also calculated and was found that it is 1.0~1.2 mm in a natural falling. The solutions of a long interval of 324 ms are shown.

Least square evaluation of head injury criterion (HIC) for various situations

Accurate evaluation of fall accidents is needed on the effect of protectors such as helmet or safety cap to reduce the shock from the impact to head is very important. We have done the experiment in JARI using human-type robot which simulates the human accidental injury. The precise data of acceleration has been taken from the robot, then HIC has been calculated for all the experiment. We have done the least square analysis to analyze the effects of various situations (variables) for stepwise process. Finally we calculate separate effect of HIC (average) of each variable, which is most plausible. Form the result, It is concluded that the effect of the helmet is amazing, which reduces HIC by 5903. On the other hand, the effect of the safety cap is not so large, the reduction is 1833 (about one third of helmet). The increase of the cart and bicycle is similar. In this way, we determine the reduction values of HIC using least square method. This values are valuable to predict or summarize the various effects of the situation.