The ultrastructural basis for the extremely rapid contraction-relaxation cycle (up to 300 s(-1)) in the swim-bladder muscle (SBM) of a scorpionfish (Sebastiscus marmoratus), producing characteristic sounds for communication, was investigated by electron microscopy. The SBM fibres contained well-developed sarcoplasmic reticulum (SR) showing triadic contacts with well-organized transverse tubules (T tubules). It was newly found that different types of triadic contacts were present within the single SBM fibre. In the middle region of the fibre (approximately 54% of the fibre length), the triadic contacts were located around the level of boundary between the A- and I-bands (AI-type triad). However in the two end regions of the fibre (approximately 21% and approximately 12% of the fibre length), the triadic contacts were seen around the level of the Z-band (Z-type triad). Between the middle and end regions of the fibre, T tubule-SR contacts exhibited the form of pentads composed of a pair of T tubules and three SR elements, and newly found heptads composed of three T tubules and four SR elements. The fractional volume of SR relative to the fibre volume was estimated to be approximately 26% in the middle region of the fibre with the AI-type triads and approximately 15% in the fibre ends with the Z-type triads. These results are discussed in connection with the mechanism, by which the mechanical activity of the SBM muscle is neurally controlled.
Emotion is an internal and subjective experience that plays a significant role in human life. There are several methods of recognizing emotions in people, the most authentic of which is using physiological signals, as they are beyond one's control and strongly correlated with human emotions. This study aims to develop an emotion recognition system based on three physiological signals, namely, brainwave, heartbeat, and facial muscular activity. It utilizes deep neural network (DNN) and the T method of Mahalanobis-Taguchi system (MTS) to process the multiple physiological signals and further recognize the states of human emotion. As such, nine emotions are effectively recognized on a two-dimensional model through the DNN, then compared against several other algorithms, such as MTS, SVM, Naive Bayes, and K-means, where its superior accuracy is validated. Moreover, although the T method only improves the classification accuracy on the valence state, it rather obtains the intensity of emotion in different states. Furthermore, in this study, the proposed DNN is implemented into a wide range of applications for an accurate understanding of the human emotional states, whereas the T method is utilized to respond to the emotional intensity in different states. Finally, a real-time emotion recognition system is developed with DNN as the classifier; this system can directly monitor the variation of the human emotion through reliable and objective emotion analysis results from the physiological signals. Thus, the method can provide useful treatment effect information for robots or assistive apparatus serving activities of daily living.
Wearable assistive devices have been receiving considerable attention in academic circles. To make these devices efficient, we need additional research on the service lives of the mechanical elements used in these devices. The wearers of these devices frequently encounter unexpected movements that lead to motor failure in the devices. The purpose of this study is to develop an overload protection mechanism using a torque limiter, which can eliminate the overload torque delivered in the reverse direction to effectively prevent the device from breaking and ensure the safety of the user. To improve the service life of assistive walking devices, we designed a sandwich mechanism for the final gear of the servo motor. We made the material from rubber and configured it between a pair of circular plates. The surface tractive force delivered the required torque. When the surface load exceeded the maximum friction force, the circular plates slipped and protected the device. In this paper, we implement a torque limiter and prove its durability by performing experiments using two circular plate designs, one with grooves type and another without grooves type. We also use various materials to assess the applicability of the assistive walking device. The findings indicate that the with grooves type gives better torque performance; it achieves the same rated torque as the servo motor. Thus, this study recommends that with grooves type is particularly suitable for the elderly who require high assistive power. On the other hand, without grooves type is suitable for users who employ the device for extended periods because this type has an excellent service life. Our experiment proves that the torque limiter that we developed can withstand the load torque over 300 times for situations involving the loss of balance such as stumbling and slipping. Finally, we experimentally validate the improvement of walking performance by using this torque limiter. investigated ways for supporting the elderly and people with disabilities by using an exoskeleton to walk, climb stairs, and carry things around. Saglia et al. (2009) used a rehabilitation robot to enable the ankle to perform plantar/dorsiflexion and inversion/eversion by using a parallel mechanism. Sankai (2010) developed an assistive device for people who suffered from muscular weakness. ReWalk TM (Esquenazi, 2012) aimed to help people who suffered from serious spinal cord injuries to regain their activities of daily living. Sanz-Merodio et al. (2014) developed lower-limb exoskeletons that helped paralyzed children walk. The tibialis anterior muscle is the muscle that is most prone to fatigue during human walking. Consequently, we have developed various assistive devices that focus on assisting the ankle joint during the walking movement. Using our designed aid devices designed, the equipped foot can be raised automatically through the neural pathway of human stretch reflex. Our findings confirmed that our device could effectively improve the gait of the user (Tanaka et al., 2015a(Tanak...
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