関根 雅

Microcirculation plays an important role by supplying oxygen and nutrients to maintain our lives. It is known that, as pathogenesis of sepsis, the microcirculation is impaired at the early stage of sepsis. In this case, it is expected that thrombomodulin alfa (TM alfa) works for the recovery of microcirculation. Direct observation of the impairment and recovery of microcirculation related to sepsis may give us clear understanding of those phenomena. In this study, we conducted experiments to observe microcirculation of septic model rats with an optical system. In these experiments, by attaching a chamber to the back of each rat, the same region of the microcirculation was consecutively monitored. Then, these rats were divided into three groups: control model rats (sham group), septic model rats (diseased group), and septic model rats to which TM alfa was administered (treated group). Each group includes five rats. In the diseased group smaller vessels disappeared and larger vessels became thinner. On the other hand, the treated group showed at first the degradation of microcirculation then the recovery. This may indicate effectiveness of TM alfa. We also estimated the blood velocity and blood vessel diameter from the acquired motion pictures to evaluate condition of the microcirculation. As a result, we quantitatively confirmed while blood velocity and blood vessel diameter of the diseased group decreased, that of the treated group decreased and then recovered. It should be noted that the set of motion pictures obtained in these experiments has potentially useful information for further analysis and is to be open to relevant researchers.

The lightness and softness of pneumatic artificial muscles (PAMs) contribute to their safe use in mechanical devices involved with humans. However, a PAM has limited range of motion (ROM) and a stroke-dependent output force. In this paper, a mechanism combined with a PAM and a speed-increasing gear was developed to improve the tradeoff relationship between the ROM and output force and to verify its benefits in order to enhance the convenience of using PAMs. The gear enhanced the ROM and back-drivability of the PAM, which is beneficial for device safety in daily use. We first designed a mechanism consisting of an antagonistic system-driven PAM and the gear, and then simulated the relationship between the ROM and output force of the mechanism. The effectiveness of the mechanism including the gear was compared with a non-gear mechanism with multiple PAMs. We prototyped the PAM mechanism with and without the gear, and their ROMs, impact absorption, and viscoelasticity were experimentally investigated. Results showed that the gear effectively improved both ROM and output torque below a certain load moreover, the gear ratio and air pressure had large effects on the external static and dynamic forces, respectively. We confirmed comprehensively the effect and feasibility of the mechanism.

Tomosynthesis is attracting attention as a low-dose tomography technology compared with X-ray CT. However, conventional tomosynthesis imaging devices are large and stationary. Furthermore, there is a limitation in the working range of the X-ray source during image acquisition. We have previously proposed the use of a portable X-ray device for tomosynthesis that can be used for ward rounds and emergency medicine. The weight of this device can be reduced by using a flat panel detector (FPD), and flexibility is realized by the free placement of the X-ray source and FPD. Tomosynthesis using a portable X-ray device requires calibration of the geometry between the X-ray source and detector at each image acquisition. We propose a method for geometry calibration and demonstrate tomosynthesis image reconstruction by this method. An image processing-based calibration method using an asymmetric and multilayered calibration object (AMCO) is presented. Since the AMCO is always attached to the X-ray source housing for geometry calibration, the additional setting of a calibration object or marker around or on the patients is not required. The AMCO's multilayer structure improves the calibration accuracy, especially in the out-of-plane direction. Two experiments were conducted. The first was performed to evaluate the calibration accuracy using an XY positioning stage and a gonio stage. As a result, an accuracy of approximately 1 mm was achieved both in the in-plane and out-of-plane directions. An angular accuracy of approximately was confirmed. The second experiment was conducted to evaluate the reconstructed image using a foot model phantom. Only the sagittal plane could be clearly observed with the proposed method. We proposed a tomosynthesis imaging system using a portable X-ray device. From the experimental results, the proposed method could provide sufficient calibration accuracy and a clear sagittal plane of the reconstructed tomosynthesis image.

It has been shown that mobile robots could be a potential solution to home bio-monitoring for the elderly. Through our previous studies, a mobile robot system that is able to recognize daily living activities of a target person has been developed. However, in a home environment, there are several factors of uncertainty, such as confusion with surrounding objects, occlusion by furniture, etc. Thus, the features extracted could not guarantee the correct recognition. To solve the problem, we applied active sensing strategy to the robot, especially to the body contour based behavior recognition part, by implementing 3 algorithms in a row, which enabled (1) judging irregularity of feature extraction; (2) adjusting robot viewpoints accordingly; (3) avoiding excessive viewpoint adjustment based on a short-term memory mechanism, respectively. As a result of experiment in a home living scenario, higher activity recognition accuracy was achieved by the proposed active sensing algorithms.

The main function of a hand is to grasp and manipulate objects, and the thumb contributes most to this function. However, thumb rehabilitation devices, especially soft robotic gloves, have not been widely investigated. Soft pneumatic actuators are lighter, more flexible, and easier maintenance than other actuators. This makes them safer and more cost-effective. In this paper, we present a design for a soft robotic thumb rehabilitation system. We used a soft pneumatic actuator for bending (SPAB) for flexion-extension motion. For the carpometacarpal (CMC) joint, we used a parallel link mechanism by placing pneumatic artificial muscles (PAM) around it in three directions. We evaluated whether this setup of SPAB and PAM could enable the required three-dimensional thumb motions by using a prototype system on a dummy thumb. The results showed that the proposed mechanism enables opposition, abduction, and adduction motions for the thumb.

In developing a shoulder prosthesis, in addition to appropriate payload and range of motion under the constraints of weight and shape, impact absorption is very important for safe use. Hybridization of two different actuators (pneumatic elastic actuators with the features of lightness and intrinsic visco-elasticity, and servo motors that have stable torque and a large range of motion in combination with an antagonistic mechanism) was employed to achieve the development of the shoulder prosthesis. A two-link, two-degree-of-freedom arm was used to test the different hybridization configurations in order to investigate the impact absorption. A dynamic simulation platform based on four bimanual activities of daily living was established to obtain the required range of motion and torque for joints of a two-link, four-degree-of-freedom arm. The number of pneumatic elastic actuators required and the dimension of the antagonistic mechanism mechanical structures were optimized using the dynamic simulation platform. The best configuration of the two types of actuators was determined using the dynamic simulation based on the impact absorption results and other criteria. Moreover, a simplified prototype driven by hybrid actuation was made. It was shown that the pneumatic elastic actuator joint could improve impact absorption, and the actuator configuration of shoulder prostheses is activity of daily living dependent. The prototype could reproduce a certain activity of daily living motion, indicating its feasibility in daily living.

Increasing population age demands more services in healthcare domain. It has been shown that mobile robots could be a potential solution to home biomonitoring for the elderly. Through our previous studies, a mobile robot system that is able to track a subject and identify his daily living activities has been developed. However, the system has not been tested in any home living scenarios. In this study we did a series of experiments to investigate the accuracy of activity recognition of the mobile robot in a home living scenario. The daily activities tested in the evaluation experiment include watching TV and sleeping. A dataset recorded by a distributed distance-measuring sensor network was used as a reference to the activity recognition results. It was shown that the accuracy is not consistent for all the activities; that is, mobile robot could achieve a high success rate in some activities but a poor success rate in others. It was found that the observation position of the mobile robot and subject surroundings have high impact on the accuracy of the activity recognition, due to the variability of the home living daily activities and their transitional process. The possibility of improvement of recognition accuracy has been shown too.

The purpose of this study is to design a new surgical scissors handle and determine its effectiveness with various usability indices. A new scissors handle was designed that retains the professional grip but has the shapes of the eye rings modified to fit the thumb and ring finger and finger rests for the index and little finger. The newly designed scissors and traditional scissors were compared by electromyography, subjective evaluation and task performance in experiments using cutting and peeling tasks. The newly designed scissors reduced muscle load in both hand during cutting by the closing action, and reduced the muscle load in the left hand during peeling by the opening action through active use of the right hand. In evaluation by surgeons, task performance improved in addition to the decrease in muscle load. The newly designed scissors used in this study demonstrated high usability.Practitioner Summary: A new scissors handle was designed that has the eye rings modified to fit the thumb and ring finger. The newly designed scissors reduced muscle load and enabled active use of the right hand. In evaluation by surgeons, task performance improved in addition to the decrease in muscle load.

Unlike forearm amputees, transhumeral amputees have residual stumps that are too small to provide a sufficient range of operation for their prosthetic parts to perform usual activities of daily living. Furthermore, it is difficult for small residual stumps to provide sufficient impact absorption for safe manipulation in daily living, as intact arms do. Therefore, substitution of upper limb function in transhumeral amputees requires a sufficient range of motion and sufficient viscoelasticity for shoulder prostheses under critical weight and dimension constraints. We propose the use of two different types of actuators, ie, pneumatic elastic actuators (PEAs) and servo motors. PEAs offer high power-to-weight performance and have intrinsic viscoelasticity in comparison with motors or standard industrial pneumatic cylinder actuators. However, the usefulness of PEAs in large working spaces is limited because of their short strokes. Servo motors, in contrast, can be used to achieve large ranges of motion. In this study, the relationship between the force and stroke of PEAs was investigated. The impact absorption of both types of actuators was measured using a single degree-of-freedom prototype to evaluate actuator compliance for safety purposes. Based on the fundamental properties of the actuators identified, a four degree-of-freedom robotic arm is proposed for prosthetic use. The configuration of the actuators and functional parts was designed to achieve a specified range of motion and torque calculated from the results of a simulation of typical movements performed in usual activities of daily living. Our experimental results showed that the requirements for the shoulder prostheses could be satisfied.

Transhumeral and shoulder disarticulation amputees find it difficult to move their prostheses for goal-oriented movement using only their small residual limbs. Thus, spatial accessibility is especially important for shoulder prostheses. Moreover, because responding to external disturbances and absorbing impact using only the viscoelasticity and flexibility of the small residual limb is difficult, the intrinsic viscoelasticity of the shoulder prosthesis is indispensable for safety. In our previous work, we proposed a small pneumatic elastic actuator-driven parallel link mechanism for shoulder prostheses. In this paper, we propose two new devices, a sliding antagonistic mechanism and a soft backbone, to improve the spatial characteristics and disturbance responsiveness. We quantitatively evaluated a prosthetic arm with the two devices. The results showed that the two devices increased the arm's workspace and disturbance responsiveness.

Saliency maps as visual attention computational models can reveal novel regions within a scene (as in the human visual system), which can decrease the amount of data to be processed in task specific computer vision applications. Most of the saliency computation models do not take advantage of prior spatial memory by giving priority to spatial or object based features to obtain bottom-up or top-down saliency maps. In our previous experiments, we demonstrated that spatial memory regardless of object features can aid detection and tracking tasks with a mobile robot by using a 2D global environment memory of the robot and local Kinect data in 2D to compute the space-based saliency map. However, in complex scenes where 2D space-based saliency is not enough (i.e., subject lying on the bed), 3D scene analysis is necessary to extract novelty within the scene by using spatial memory. Therefore, in this work, to improve the detection of novelty in a known environment, we proposed a space-based spatial saliency with 3D local information by improving 2D space base saliency with height as prior information about the specific locations. Moreover, the algorithm can also be integrated with other bottom-up or top-down saliency computational models to improve the detection results. Experimental results demonstrate that high accuracy for novelty detection can be obtained, and computational time can be reduced for existing state of the art detection and tracking models with the proposed algorithm.

The mechanical and biological effects of ultrasonically activated devices (USADs) were analyzed with two different types of blade and addressed the question of whether USADs could be the direct cause of postoperative pancreatic fistula (POPF) after laparoscopic gastric cancer surgery. A laparoscopic USAD handpiece with a straight blade or a curved blade was used with an appropriate generator. Both devices employ an ultrasonic energy of 55.5 kHz for activation. The blade was activated while its handpiece was fixed on a precision positioning table mounted on a metal framework in all the experiments To determine the independent and combined effects of the activation time, the number of broken foil layers and the site of contact, comparisons between groups were performed by three-way ANOVA followed by multiple comparison testing using the Bonferroni correction. The mean number of broken aluminum foil layers significantly increased as the activation time increased for both types of blade Pairwise comparison of the blade type and contact site revealed a significant difference between straight and curved blades regarding the tip and the side, respectively.

Saliency maps as visual attention computational models can reveal novel regions within a scene (as in the human visual system), which can decrease the amount of data to be processed in task specific computer vision applications. Most of the saliency computation models do not take advantage of prior spatial memory by giving priority to spatial or object based features to obtain bottom-up or top-down saliency maps. In our previous experiments, we demonstrated that spatial memory regardless of object features can aid detection and tracking tasks with a mobile robot by using a 2D global environment memory of the robot and local Kinect data in 2D to compute the space-based saliency map. However, in complex scenes where 2D space-based saliency is not enough (i.e., subject lying on the bed), 3D scene analysis is necessary to extract novelty within the scene by using spatial memory. Therefore, in this work, to improve the detection of novelty in a known environment, we proposed a space-based spatial saliency with 3D local information by improving 2D space base saliency with height as prior information about the specific locations. Moreover, the algorithm can also be integrated with other bottom-up or top-down saliency computational models to improve the detection results. Experimental results demonstrate that high accuracy for novelty detection can be obtained, and computational time can be reduced for existing state of the art detection and tracking models with the proposed algorithm.

Postoperative pancreatic fistula (POPF) has been suggested to occur more frequently in laparoscopic gastrectomies than conventional open gastrectomies. Ultrasonically activated devices (USADs) have been raised as one of the causes of POPF. This research has been conducted to determine whether USADs could be the direct cause of POPF. USAD activation in degassed water showed cavitation bubbles generated on the surface of both the tip and side aspect of the blade. Physical analysis of destructive capability of the activated blades using aluminum foils indicated no significant differences between the tip and the side aspect of the blade. Analysis of biological tissue damages caused by energy devices revealed histological differences of pancreatic tissue injuries between electric scalpel and USAD. These data suggest that USADs could cause POPF and the side aspect as well as the tip of the USAD's blade should not be in touch with the parenchyma of the pancreas during activation of the system as far as possible.

WaFLES (Water-Filled LaparoEndoscopic Surgery) is an operative method suggested by Igarashi et al., which has several advantages, such as, preventing the drying of inner organs, and being able to use ultrasound devices for real time monitoring. However, grasping of inner organs with usual forceps for move and incision purpose is difficult. Therefore our ultimate goal is to develop a small sucker manipulator for WaFLES support. Experiments were conducted to explore suitable suction cups for underwater application, and suitable structure (cup-to-cup distance, elasticity of binding material, layouts of multiple cups) for a multiple-cup assembly, in terms of adsorption force and tolerance to sideslip. Experiment results showed that 1) the shape of each single suction cup for the underwater application was identified; 2) the structure of the multiple-cup assembly affects the adsorption force and tolerance to sideslip.

Lightweight prostheses are preferred in terms of usability in daily living. However, this is not a property easy to realize, especially for shoulder prostheses. High portability, multiple degrees of freedom (DOFs) with an appropriate ROM (range of motion), sufficient end-effector power, and suitable viscoelasticity for the safe use in daily living, usually result in a heavy weight. In this paper, a hybrid shoulder prosthesis that combined servo motors and pneumatic elastic actuators, with a weight distribution scheme, was designed to meet the requirements. The prosthetic system was preliminarily tested by comparing its ADL (activities of daily living) motion data with that of an intact arm. The experiment results showed that the shoulder prosthesis could reproduce the motion of an intact arm, thus demonstrate its usability in daily living.

Our research is focused on the development of an at-home health care biomonitoring mobile robot for the people in demand. Main task of the robot is to detect and track a designated subject while recognizing his/her activity for analysis and to provide warning in an emergency. In order to push forward the system towards its real application, in this study, we tested the robustness of the robot system with several major environment changes, control parameter changes, and subject variation. First, an improved color tracker was analyzed to find out the limitations and constraints of the robot visual tracking considering the suitable illumination values and tracking distance intervals. Then, regarding subject safety and continuous robot based subject tracking, various control parameters were tested on different layouts in a room. Finally, the main objective of the system is to find out walking activities for different patterns for further analysis. Therefore, we proposed a fast, simple, and person specific new activity recognition model by making full use of localization information, which is robust to partial occlusion. The proposed activity recognition algorithm was tested on different walking patterns with different subjects, and the results showed high recognition accuracy.

Human arms undertake most tasks in the activities of daily living (ADLs). When designing shoulder prostheses for high-level upper-limb amputees, we should consider not only how to realize high degrees of freedom under weight and shape constraints but also the user's individual task space in daily life. An appropriate mechanical structure that can make full use of state-of-the-art actuators and a scheme to optimize the structure's configuration to match users' spatial access and manipulability requirements are essential. In our previous research, a small pneumatic-actuator-driven parallel mechanism was studied as a shoulder prosthetic arm. In this paper, a systematic procedure is proposed to design the mechanism for a shoulder prosthesis considering force and spatial accessibility. This procedure includes ADL measurements to obtain the task spaces for individual subjects, indexes to evaluate the force and spatial accessibility and an optimization process based on kinematic and statics models. With this approach, the parallel mechanism was optimized for one important ADL task group, considering the trade-off between its required force and working space. Moreover, it was confirmed that the proposed design procedure could find solutions for various spatial specifications. That is, the approach could be used for individualized shoulder prosthesis design.

Electrothermal bipolar vessel sealing devices have been used for the ligation of vessels during surgical procedures. However, unexpected bleeding is still reported, the cause of which is not yet clarified by conventional histopathological analysis. In the present study, ultrasonic microscopy with a central frequency of 80MHz was applied to evaluate the mechanical properties of ligated vessels. Five arteries and five veins were electrically sealed for 0, 2, 4, 6, and 8 s. The speed of sound in the native adventitia were higher than that in the media. The speed of sound was not correlated with sealing time. However, acoustical inhomogeneity was seen in the sealed vessels. Thus, the acoustical properties of vessels may be affected by the electrothermal effect, and the evaluation of mechanical properties is important for assessing the tissue sealing performance. (c) 2013 The Japan Society of Applied Physics

PurposeThe aim of this paper is to develop autonomous mobile home healthcare robots, which are capable of observing patients’ motions, recognizing the patients’ behaviours based on observation data, and providing automatically calling for medical personnel in emergency situations. The robots to be developed will bring about cost-effective, safe and easier at-home rehabilitation to most motor-function impaired patients (MIPs). Design/methodology/approachThe paper has developed following programs/control algorithms: control algorithms for a mobile robot to track and follow human motions, to measure human joint trajectories, and to calculate angles of lower limb joints and algorithms for recognizing human gait behaviours based on the calculated joints angle data. FindingsA Hidden Markov Model (HMM) based human gait behaviour recognition taking lower limb joint angles and body angle as input was proposed. The proposed HMM based gait behaviour recognition is compared with the Nearest Neighbour (NN) classification methods. Experimental results showed that a human gait behaviour recognition using HMM can be achieved from the lower limb joint trajectory with higher accuracy than compared classification methods. Originality/valueThe research addresses human motion tracking and recognition by a mobile robot. Human gait behaviour recognition is HMM based lower limb joints and body angle data from extracted from kinect sensor at the mobile robot.

Our research is focused on the home healthcare support system for motor function impaired persons (MIPs) whose motor function should be closely monitored during either in-hospital or at-home training therapy process. Especially, for the at-home monitoring, the demand of which is increasing, not only close observation, but also accurate behavior recognition of daily living activity, as well as motor function evaluation, are necessary. In this study, such a system was established by developing a cost-effective, safe and easy to use mobile robot. With such a robotic monitoring system, the in-hospital time for most MIPs and the burden to therapists can be significantly decreased. In order to realize the robotic monitoring system, we proposed several algorithms to solve the difficulties arising from the mobile sensing for moving MIPs, and recognize several frequent daily living activities, including impaired walking. Concretely, algorithms to use both color images and depth images was proposed to improve the accuracy of MIPs measurement, and a Hidden Markov Model (HMM) was implemented to deal with the uncertainty on time sequence data and relate the state transitions over time for daily living activity recognition. Experiments have demonstrated promising results on joint trajectory measurement, and recognition of daily living activities. © 2013 Springer-Verlag Berlin Heidelberg.

Background: Prosthetic hand users have to rely extensively on visual feedback, which seems to lead to a high conscious burden for the users, in order to manipulate their prosthetic devices. Indirect methods (electro-cutaneous, vibrotactile, auditory cues) have been used to convey information from the artificial limb to the amputee, but the usability and advantages of these feedback methods were explored mainly by looking at the performance results, not taking into account measurements of the user's mental effort, attention, and emotions. The main objective of this study was to explore the feasibility of using psycho-physiological measurements to assess cognitive effort when manipulating a robot hand with and without the usage of a sensory substitution system based on auditory feedback, and how these psycho-physiological recordings relate to temporal and grasping performance in a static setting. Methods: 10 male subjects (26+/-years old), participated in this study and were asked to come for 2 consecutive days. On the first day the experiment objective, tasks, and experiment setting was explained. Then, they completed a 30 minutes guided training. On the second day each subject was tested in 3 different modalities: Auditory Feedback only control (AF), Visual Feedback only control (VF), and Audiovisual Feedback control (AVF). For each modality they were asked to perform 10 trials. At the end of each test, the subject had to answer the NASA TLX questionnaire. Also, during the test the subject's EEG, ECG, electro-dermal activity (EDA), and respiration rate were measured. Results: The results show that a higher mental effort is needed when the subjects rely only on their vision, and that this effort seems to be reduced when auditory feedback is added to the human-machine interaction (multimodal feedback). Furthermore, better temporal performance and better grasping performance was obtained in the audiovisual modality. Conclusions: The performance improvements when using auditory cues, along with vision (multimodal feedback), can be attributed to a reduced attentional demand during the task, which can be attributed to a visual "pop-out" or enhance effect. Also, the NASA TLX, the EEG's Alpha and Beta band, and the Heart Rate could be used to further evaluate sensory feedback systems in prosthetic applications.

Upper limb amputees have to rely extensively on visual feedback in order to monitor and manipulate successfully their prosthetic device. This situation leads to high consciousness burden, which generates fatigue and frustration. Therefore, in order to enhance motor-sensory performance and awareness, an auditory display was used as a sensory feedback system for the prosthetic hand's spatio-temporal and force information in a complete reaching and grasping setting. The main objective of this study was to explore the effects of using the auditory display to monitor the prosthetic hand during a complete reaching and grasping motion. The results presented in this paper point out that the usage of an auditory display to monitor and control a robot hand improves the temporal and grasping performance greatly, while reducing mental effort and improving their confidence.

In this study, several indexes for spatial accessibility were proposed for evaluating the shoulder prosthesis with a small pneumatic actuator driven parallel mechanism in daily living use. Using the spatial accessibility indexes and manipulability indexes, the configuration of the parallel mechanism was optimized. Especially, the effect of biasing spacer and trunk motions on spatial accessibility were taken into consideration. The results showed that biasing spacers could improve the spatial accessibility by moving the center of the working space of the shoulder prosthesis towards the center of two specified spatial regions, which correspond to the expected frequently accessed area and the reachable area for an individual user's upper limb in daily living. And trunk motions could enlarge the working space thus further improve the spatial accessibility.

The shoulder prosthesis with a small pneumatic actuator driven parallel mechanism in daily living use, was suggested in this study. The configuration of the parallel link arm was optimized by means of the spatial accessibility and manipulability indexes for appraising the shoulder prosthesis. In particular, the effectiveness of biasing spacer was taken into consideration. The results showed that biasing spacers could improve the spatial accessibility. Eventually, the prototype was built on the basis of the optimal configuration, we validated the arm behavior and the availability of biasing spacers experimentally.