Training under a medical professional is crucial to learn myoelectric prosthesis operation successfully and efficiently. To compensate the limited training time, it is essential to minimize the time consumed for sensor adjustment. The object of this research is to develop an adjustment process for myoelectric signal to stably operate the prosthetic device with minimal frequency observation by medical professional, especially during the take-home training. Quality Engineering RT method is applied as a pattern-recognition-based sensitivity adjustment. The relation of RT method's sample data number and discrimination rate is investigated while observing dissimilarity's validation are efficient as expectation function of the discrimination rate. and by experiment. Myoelectric sensor signal form 5 subject's forearm was processed with 10, 30, 50 sample data. As result, discrimination rate did not have explicit increase/decrease trend to the sample data number and could not be explained by dissimilarity's validation, and differed by subjects.

According to a survey conducted by the Ministry of Health, Labor and Welfare, one in five Japanese people say that they do not get enough rest from sleep, and there is a growing need to ensure restful sleep based on objective evaluation of sleep status. Polysomnography is a method of measuring sleep state, but it is used for medical purposes and requires many sensors such as electroencephalogram, eye movement, etc., making it difficult to measure at home on a daily basis. In this study, we aimed to develop a method for unconstrained and reliable sleep stage estimation by integrating and analyzing video information from two viewpoints. We apply machine learning to the feature extraction results of thorax motion, body movement, and apnea from the horizontal viewpoint, and the feature extraction results of nasal skin temperature from the frontal viewpoint. We confirmed the effectiveness of the proposed method through evaluation experiments.

We investigated a low-load stress measurement algorithm using tablets and verified its effectiveness. The subjects took the Kleperin test as a stressor, and before and after that, they were ordered to move their finger to unlock the pattern lock on the tablet screen. At the same time, their heart rates were measured. From the measurement results, a strong negative correlation was found between the speed of finger movement and the heart rate after taking the Kleperin test. This indicates that the speed of finger movement may reflect the activity of the sympathetic nerve. Next, we investigate the relative error (stability) of the finger. As a result, after taking the Kleperin test, the stability decreased in the stroke of moving right to left. This indicates that there may be a negative correlation between stability and stress. In the future, we plan to study more effective measurement and evaluation methods.

To investigate bio-responses to pleasant stimuli, we conducted an experiment involving gustatory, olfactory, and auditory stimuli. We measured the responses of 15 test subjects, who gave informed consent to participate. The subjects tasted a piece of chocolate, smelled the aroma of "orange sweet," and listened to "koi" for gauging the gustatory, olfactory, and auditory stimuli, respectively. A sitting subject rested for 90 s before being exposed to stimuli for 90 s, after which he rested for 40 s. We continuously monitored the blood pressure, electrocardiogram, respiratory wave, and photoplethysmogram for each test subject. In the results, blood pressure increased for auditory stimuli. Likewise, heart rate and respiratory depth increased for gustatory stimuli. We analyzed the combined parameter at a specific part of the pulse wave and observed an increase against control for every stimulus.

The purpose of this study is to evaluate relationship between cardiac autonomic nervous system (CANS) activity with Tone-Entropy analysis and sleep stages. The 7 subjects were participated, and performed polysomnography (PSG) in this experiment. An experienced scorer estimated sleep stages by AASM scoring manual (Ver.2.1.). Tone-Entropy analysis was calculated from heart rate variability to evaluated CANS. Tone (mean+/-S.D.) of sleep stages were -0.277+/-0.650 (Wake), -0.443+/-0.611 (REM), -0.461+/-0.714 (N1), -0.476+/-0.718 (N2), -0.281+/-0.361 (N3). Entropy (mean+/-S.D.) of sleep stages were 4.19+/-0.38 (Wake), 4.31+/-0.57 (REM), 4.38+/-0.51 (N1), 4.38+/-0.51 (N2), 4.20+/-0.62 (N3). The authors conducted a within-subjects Tukey test on the conditions, and the result did not show any significant difference. In conclusion, our results suggest that Tone-Entropy analysis dose not relate sleep stages.

Traffic accidents from the health condition of truck drivers is a social issue. We are developing a technology to detect danger in advance using physiological information. Our purpose is to analyze the changes over time in autonomic nervous function (ANF) estimated from heart rate variability analysis (HRV), and to predict the future risk of accidents while driving. During driving, it is necessary to adapt to a dynamic ANF environment different from the conventional static one. Therefore, we proposed a time series prediction method using two preprocessing and Deep Learning model. First, we extracted ANF index by continuous HRV with the optimized window width, and normalized data to eliminate individual differences. Then, environmental factors affecting ANF and accident risk were added to input. As results, Recall was 88.8% and AUC was 0.84. Even in during driving, ANF is effective for prediction of accident risk and it can contribute to accident prevention.

The purpose of this study is to compare the surgeon's heart rate variabilities during robotic-assisted, laparoscopic, and abdominal radical hysterectomy for uterine cervical cancer. The authors measured the R-R interval sequences of one surgeon during each operation. The heart rate and heart rate variability were calculated and compared frequency-domain analysis, Total Power, HF, LF/HF ratio, time-domain analyses, and Tone and Entropy associated with the autonomic nervous system (ANS) activity. Our results showed that the ANS activity, mainly parasympathetic activity, during the robotic-assisted operation was increased more than laparoscopic or abdominal approaches. In addition, our results indicated that Tone-Entropy analysis might enable us to evaluate physical load and mental stress superior to other analyses.

Background: Power spectral density (PSD) is often used for frequency analysis of brain signal measured by magnetoencephalography (MEG). Parameters calculated from the PSD have been studied as potential biomarkers of dementia and mild cognitive impairment (MCI). In this study, to evaluate classification performance of the PSD-derived parameters quantitatively, we compared them between healthy controls (CTR), patients with MCI, and dementia (DEM), using machine learning approach.Method: PSD was calculated from spontaneous MEG signals (139 CTR, 38 MCI, and 57 DEM) measured at the Kumagaya General Hospital. As the parameters, median frequency, individual alpha frequency, and Shannon entropy were calculated. The parameters were compared between the groups and the classification performance was evaluated using SVM classifier.Results: All parameters were significantly different between the groups. The classification accuracy was improved using SVM.Discussion: The classification performance of PSD-derived parameters were replicated. Each parameter captures distinctive features of PSD.

W examined psycho-behavioral associations in the elderly, as well as their alterations with the depressive tendencies. We recorded subjective symptoms (e.g., depressed mood; 3 times/day) from the elderly (20 subjects; 77.3±25.6 yrs; 11 males) in daily life, together with physical activity using an actigraph (>1 week). Multilevel modeling was adopted to analyze relations between depressive mood scores and mean activity levels during 60-minutes before each recording of symptoms. The significant negative correlation was found (p<0.05; coefficient: -0.02). Further, the elderly with depressive tendencies showed the significant lower coefficient close to zero (coefficient: 0.0005). This means that the psycho-behavioral associations collapsed to be uncorrelated in the depressed group. In addition, they showed lower scores in questionnaires on both well-being and life functions. Those findings suggest that alterations in psycho-behavioral associations is an early warning signal for the worsening of physical and psychological states in the elderly.

We have created experimental conditions for "development of training methods for endovascular treatment using eye movements".This method can reduce the burden on the doctor and measure eye movements.As a result of acquiring and analyzing the data of two doctors so far, it was confirmed that there is a difference in eye movement between experts and beginners.Furthermore, by improving the experimental conditions, more stable measurement has become possible.The eye movement data of 6 doctors that we measured and analyzed are shown. We would like to discuss this result.

As the consistent quantitative evaluation and training of heart-lung machine operation had not been realized yet by relevant existing simulators, in this study, a simulator was upgraded for realizing it and the educational effect by this realization was evaluated. This upgraded simulator can generate troubles in the simulation circuit, calculate evaluation from operation data, present optimal training, and perform operation training using moving images.The educational effect due to the use of this simulator were evaluated by the experiment in which 12 experimental subjects were divided into 2 groups, one that used it and the other that did not. As a result, the significant difference was not found on the educational effect, however some evaluation values concerned with it were improved by using the upgraded simulator. Therefore, the experiment with more subjects is necessary for more precise evaluation of this simulator, as reviewing the training content.

In education of cardiopulmonary bypass (CPB) for clinical engineers (CE), its long-term on-the-job training (OJT) is often required, in which the burden comes on CE supervising OJT. Thus, in this study, a training support system for CPB is been developing. This system cannot only monitor and warn of reservoir levels but also instruct on operating procedures. Moreover, the line of sight movement can be reduced by projecting the instruction onto the smart glasses which the user wears.The system was tested with the 10 healthy subjects, divided into 2 groups. The group A tried the system first and the human voice guidance second. The group B tried in reverse order. In the result, the group B was better than the group A on the score of availability in the second try. Therefore, this system can be available for use in self-training, after OJT or the learning with human voice guidance.

Pericardiocentesis is a procedure in which a needle is inserted into the pericardial space from outside the body to collect and drain pericardial fluid and relieve pressure on the heart. However, the pericardium and heart are not visible during puncture, and the heart is beating, so the insertion of the needle must be precisely controlled and punctured without over-puncturing the myocardium. In this study, we developed a phantom that simulates the skin and subcutaneous fat of a patient's abdomen and chest for puncture training, and a new sensor-implantable puncture needle device that can measure the puncture force from outside the body. We performed pericardiocentesis on the simulated pericardium of the heart simulator and measured the puncture force. The timing of pericardial penetration and the puncture force at the time of penetration were derived from the measured puncture force, and quantitative evaluation as a training device was performed.

Background: The objective of this study is to assess the feasibility to apply deep learning-based spatiotemporal video analysis using a three-dimensional convolutional neural network (3D-CNN) to automatic surgical skill assessment (ASSA).

Methods: Laparoscopic colorectal surgical videos with reliable skill assessment scores were collected from the Japan Society for Endoscopic Surgery, and among them, 74 laparoscopic colorectal surgical videos were utilized for this study. A total of 1480 video clips were extracted, and divided 4:1 for the training and the test set, respectively.

Results: The proposed 3D-CNN model could automatically classify video clips into 3 different score groups (i.e., <Average-2SD, Average±SD, and >Average+2SD) with 75.0% accuracy and screen for <Average-2SD score group with 94.1% sensitivity and 96.5% specificity.

Conclusions: 3D-CNN, which can analyze videos instead of static images had the potential to be applied to ASSA.

It is known that an electric current flows when ion-selective membrane proteins are inserted into the droplet interface bilayers (DIB). However, no method has been developed to control this current; therefore, we attempted to control the ionic current through the droplet network using carbon nanotubes (CNTs), which also have ion-selectivity. As a preliminary step, we have formed the DIB by binding droplets in lipids, and investigated the correlation between the membrane area and the capacitance of lipid bilayers in this research. The results show that there is a strong correlation between the membrane area and the capacitance, which verifies the usefulness of the experimental system. We have also measured the conductance of CNTs. A bimodal histogram has been obtained for the conductance indicating the insertion of CNTs into the lipid bilayer.

In this paper, a non-contact moisture measurement on the electrical living body model is demonstrated by an electrostatic sensor. The electrostatic sensor consists of two electrodes, which respectively measures the induced voltage and the constant voltage is impressed. The induced voltage is obtained by which the sensor is approached and separated from the target and varied by water content in the surface area of the target. The moisture in the surface area of the target is possible by the sensor. However, it is necessary to reduce the distance error since the induced voltage depends on the distance between the sensor and the target. In this study, the induced voltages on the model were measured by two kinds of distance between the sensor and the model. As a result, it was possible to reduce the distance error on the non-contact moisture measurement by induced voltages.

Human-computer interfaces have been researched and developed as a communication tool for people with severe physical disabilities. In particular, as an alternative to the conventional mouse and keyboard, input devices that estimate intentions from biomedical signals are investigated. In this study, we paid attention to facial surface electromyogram (EMG) and electrooculogram (EOG), and attempted to develop a pointing device. The direction of the pointer is estimated from the EMG signals associated with the mouth movement, and the decision operation is performed from the vertical EOG signal when the user blinks voluntarily. We proposed an electrode arrangement to measure EMGs and vertical EOG simultaneously with a wireless biomedical measurement device. We experimented to evaluate the accuracy of the pointer operation with our electrode arrangement. As a result, the subjects could control the pointer in eight directions appropriately. In addition, we investigated the threshold of the EOG to detect the blink correctly.

In recent years, Sarcopenia caused by loss of muscle mass has become a problem.We need to measure Muscle mass to diagnose sarcopenia.Sarcopenia can be measured by Bioelectrical Impedance Analysis (BIA) and Dual-energy X-ray Absorptiometry (DXA).However, these methods have the problem such as high cost and very large.To solve this problem, we are investigating the use of ultrasound imaging and multichannel surface electromyography (EMG).Multichannel surface EMG can be acquired with a row of electrodes.This EMG provides a propagating wave that shows detailed information about the muscles.Therefore, we thought that a new evaluation standard could be created from multichannel surface EMG and ultrasound images.We compared propagating waves with ultrasound images.We confirmed that thick subcutaneous fat acquired fewer propagating waves and thick biceps had a faster propagation speed.The purpose of this study is to establish a new evaluation index for muscle.

In this experiment, a handheld electrode with an arc-shaped electrode mounting surface was fabricated using a plastic splint material (Easyform, Sakai Medical, Japan). A tape electrode (Ag-AgCl, 10 mm 80 mm) was attached to the electrode mounting surface, which was 80 mm length (circular arc of R 66 mm) 130 mm width, in a four-electrode configuration. Impedance measurements were performed using SFB7 (ImpediMed, Australia). Impedance measurements were performed on the rectus femoris and vastus lateralis muscles of five adult males. Impedance parameter were calculated by arc optimization using the Cole-Cole model using 172 points of Resistance and Reactance with frequencies ranging from 10 kHz to 300 kHz. Their reproducibility was analyzed using the intra-class correlation coefficient and the Bland-Altman analysis was used to analyze the error. The results showed that the ICC(1, 1) of each muscle was greater than 0.9 and no systematic error of each parameter occurred.

Brain-machine interface (BMI) is a technology to control external devices according to motor-related intentions in the brain. While many BMIs depend on visual perception of the external devices to calibrate their running states, somatosensory projections are promising to provide users with precise and quick feedback. We focus on modeling neural activities in the rat brain activity and the peripheral nerve in response to somatosensory stimuli. In this study, we stimulated a rat in the hindlimb, and simultaneously recorded the electrocorticographic (ECoG) signals and the sciatic nerve activities with a micro-needle electrode, which were analyzed with band-pass filters and the Hilbert transform to detect their envelope by each frequency band. These neural signals showed reproducible responses to the input stimuli with proper latencies. We will discuss desirable stimuli and electrode properties to develop an effective sensory projection method according to the results.

Surface electromyography(sEMG) is used to derive compound action potentials from the skin surface. The multi-channel sEMG can observe the conduction of action potentials and estimate an action potential. It is expected to be used for the application of muscle activity assessment and the diagnosis of neuromuscular diseases. To measure, it is necessary to attach multi-electrode along the muscle fibers. However, it is difficult to determine the direction of muscle fibers from the skin surface. In a previous study, a method to quantitatively determine and extract conducting waves along the electrode direction was developed. Using the method, we investigated the relationship between conducting waves and angle of the electrodes. As a result, the number of conducting waves acquired differed depending on the angle condition of the attaching electrode. We believe that the direction of the muscle fibers could be estimated by focusing on the number of conducting waves acquired.

Fatigue among ship operators has been reported as a reason for marine accidents. Thus, the causes of fatigue should be investigated. Our previous study found that crews control their posture by leveraging pitch motions at their waist using their lower limbs, which affects energy expenditure - an indicator of physical fatigue. This study aims to reveal the relationship between the crew's energy expenditure and their muscle activities by measuring their surface myoelectric signals. The surface myoelectric signals of eight participants in a small marine craft were measured at the soleus, vastus lateralis, lumbar paraspinals, and cervical paraspinals. By using multiple regression analysis, the lumbar paraspinals and body surface area were determined to especially affect energy expenditure, and these partial regression coefficients were 0.30 and 0.84, while the coefficient of determination was 0.98. This study suggests a correlation between the participants' lumbar paraspinals in maintaining posture and their energy expenditure.

In recent years, the number of traffic accidents caused by health has been increasing and the main cause is heart disease. Therefore, a technology for continuously and long-term measurement of heart rate and respiration during driving is required. To solve this problem, we proposed the measurement system that can measure heart rate and respiration during driving without contact using the coupling capacitance electrode. However, in the past, it was difficult to extract only the effects of the cardiac dynamics because the measurable distance could not be adjusted. Therefore, we clarified the relationship between the measurable distance and the electrode diameter and examined the optimum electrode diameter. As a consideration method, we performed the evaluation experiment that decide the measurable distance by SN ratio. As a result, it was found that it is possible to measure up to almost the same distance as the electrode diameter.

In recent years, the number of traffic accidents caused by health has been increasing and the main cause is heart disease. Therefore, a technology for continuously and long-term measurement of BP (blood pressure) during driving is required. To solve this problem, we considered the non-contact measurement system that estimated BP by PTT (Pulse transmission times) using the coupling capacitance electrode. We performed the verification experiment to simultaneous measure continuous BP monitor (Finometer MIDI), ECG (Electrocardiogram) and proposed system to confirm that the R-wave peaks of ECG and the peaks of proposed system are synchronized and that BP can be estimated. As a result, we report that PTT, which has a correlation with blood pressure, could be measured by the proposed system as conventional method.

We attempted to evaluate neural activities caused by implicit associations with spatial frequency (SF) in electroencephalography (EEG). An implicit association task (IAT) was used in the experiment. Subjects were presented with a square or diamond image, and an adjective word having good or bad meaning as a visual stimulus, and instructed to discriminate the attribute of stimulus by pressing a button. The IAT score indicates that the implicit association between the image and the adjective was calculated by the reaction time. The background stimulus was checkerboards with a high (0.61-1.83 cycle/degree) and low (0.12-0.17) SF. Event-related variances were calculated in the theta band from the EEG during IAT. Low SF was influenced by high SF in the IAT score. Theta variances were enhanced at latencies of 498 and 600 ms; in particular, significant differences were observed between associations and SF backgrounds at frontal area.

Mismatch negativities (MMNs) for changes of melody-contours and pitch were measured in both musicians and non-musicians. Sequences of 5 tones with melody-contours of rising-falling/falling-rising/rising/falling shapes were used as standard stimuli, and five types of deviant were generated by changing pitch of the third note of each standard stimulus. As results, larger MMNs appeared for the melody-contour change in the musicians, whereas larger MMNs were observed for pitch change in the non-musicians. In term of effects of the melody-contour shape, variations of MMN amplitude depending on the deviant stimulus were larger in the rising-falling in the non-musicians, and both in the rising-falling and the falling-rising in musicians, respectively. In addition, the MMN latency was shorter for the musician than the non-musician. These results suggested that musical experience enhances the ability to perceive sound sequences as a group and consequently improves the discrimination of melody-contours, and increases the speed of melodic processing.

Most of the whole-head magnetoencephalograph systems detect the magnetic field radial to the head surface. The magnetic field distribution induced by the brain activity in the edge region of the helmet-shaped sensor array, for example, the activity of the visual cortex, can only be partially obtained, which deteriorates the accuracy of the magnetic field source estimation. We conducted a numerical experiment and found that the accuracy of the estimation of the magnetic source at the edge of the helmet can be improved by applying vector-type magnetometers that can detect not only the radial component but also the tangential components of the magnetic field at the edge of the sensor array.

Current Induced Magnetic Modulation Spectroscopy (CIMMS) is a method of measuring bioimpedance by measuring an induced magnetic field generated when high frequency current is applied to body without electrical contact. Since current of 100kHz or more is empirically required to apply current without electrical contact, magnetic sensor capable of measuring very small magnetic field of 100kHz or more is indispensable for realizing CIMMS. We consider optical-pumped atomic magnetometer (OPAM) to be suitable. OPAM is technology for measuring magnetism using optical pumping and magneto-optical rotation in alkali metal atoms. OPAM has extremely high sensitivity and wide frequency response, however, almost reports use strict magnetic shield. Therefore, it is difficult to use it for biomagnetic measurement. Therefore, in this paper, we developed small OPAM module in which all system except recording PC fits in about 20x20cm. We also report that we achieved a sensitivity of 1.89pT/Hz^1/2 for magnetic field of 225kHz.

The authors have developed a noise reduction signal processing method, named a mobile-reference sensor method, for biomagnetic measurement systems. In this study, we proposed employing a vibration meter (VM) and a fluxgate magnetometer (FGM) as reference sensors to detect the noise generated by the cryocooler installed near a magnetoencephalography (MEG).We placed an MEG cryostat and a helium-recycling system composed of a pulse tube cryocooler inside a magnetically shielded room and connected them by a transfer tube. We measured the vibration and the magnetic noise during operating the cryocooler using the MEG sensors, the VM and the FGM with various positions. The coherence values between the MEG sensors and the mobile reference sensors were maximized when the VM and FGM were put on the top and the side of the cryocooler, respectively. The obtained results suggested that the possibility to reduce the cryocooler-related magnetic noise from the recorded MEG data.

The conventional functional MRI (fMRI) has limitations for temporal resolution and static magnetic field strength, so that we focused on spin-lock sequences to overcome these limitations. We reported that a spin-locked Mz (SL-Mz) sequence could detect 2.34 nT by 0.3-T MRI, while it was reported that 80 pT was detected by 3-T MRI. We considered that the SNR of MRIs may the reason for the difference and investigated the influence of noise on magnetic field detection. We performed MRI simulation varying both noise level and amplitude of the target signal. Subsequently, we applied statistical test for MR images with and without the target magnetic field obtained by the two spin-lock sequences, i.e., SL-Mz and stimulus-induced rotary saturation (SIRS). The results showed that the SL-Mz could detect 2 nT when SNR was 1, whereas 10 nT was detected by SIRS even higher SNR of 50-100.

We are investigating the possibility of an ultra-low field functional magnetic resonance imaging that directly images brain neural activity. Last year, we proposed a pulse sequence that extracts only the modification region due to neural currents, and examined its validity using computer simulation. In this study, we use a current dipole model as a neural activity model and examine the proposed method assuming a practical situation. The current dipole intensity and the activation time were determined using the knowledge of auditory evoked field measurements. The magnetic field near the dipole was calculated using Heller's equation considering the volume current inside the conductor sphere. It is necessary to increase the spatial resolution in order to image the neural structure, and for that purpose, it is necessary to increase the gradient field. We examined the reconstructed image when the amplitude and duration of the gradient field were changed.

Recently, optically pumped magnetometers (OPMs) using hybrid cells, which enclose two types of alkaline atoms, have been developed to homogenize sensor properties inside a hybrid cell. To measure very weak biomagnetic fields using the OPMs, it is necessary to suppress environmental magnetic noise. One of the effective ways to reduce the noise is differential measurements at more than two sensing locations. However, the frequency characteristics of hybrid OPMs are not well known, although those must be corrected to be unified. In this study, we carried out numerical simulation to correct the deviation of the resonance frequency for gradiometer configuration of a K-Rb hybrid OPM. We assumed that the static magnetic field was inhomogeneous, and considered the transfer function correcting the deviation of the frequency characteristics between two sensors. The results indicated that the correction improves the sensitivity of the differential output of the gradiometer due to noise reduction.

Introduction: Magnetoneurogram recording of the brachial plexus (BP) in the prone position requires some burden on subjects. We report on the visualization and consistently evaluation of nerve activity in the BP and cervical spinal cord in the supine position.Method: Magnetoneurogram of 3 healthy volunteers were measured around the surface of the posterior neck after median nerve stimulation. After magnetoneurogram recording, evoked action currents were computationally reconstructed and visualized by a spatial filter method in the area that was set reflected anatomically position of BP. Imaginary electrode were set along action current pathway and then calculated current waveforms.Result: In all cases, we successfully visualized action currents of BP and cervical spinal cord in the supine position. Reconstructed action currents flowed into the intervertebral foramina and traveled cranially along the spinal canal.Conclusion: We proposed evaluation method in BP and cervical spinal cord in supine position with less burden.

The purpose of this study was to develop a tool for spatiotemporal analysis of microvascular flow based on kymograph images that were captured with two-photon laser scanning fluorescence microscopy in the anesthetized rat cortex. The flow velocity of fluorescently-labeled red blood cells was determined using the Radon transform images along the centerlines of the capillaries. The velocity gradient was then determined according to a velocity profile along the vessel centerlines. We observed that the flow velocity at the confluence of two capillaries was 0.40 mm/s and the velocity gradient over the merging points was 0.004 mm/s·mm, indicating a slight increase in the velocity over the confluence. In contrast, the velocity at the bifurcation point was 0.24 mm/s and the velocity gradient was -0.011 mm/s·mm, which showed the bifurcation caused a reduction of the flow velocity.

Retractor is a medical device to expand the surgical field by compressing the tissue. However, there is a risk of serious accidents due to overloading in neurosurgery. In this study, we developed a retractor that detects signs of tissue fracture and automatically stop the compressing. We developed a retractor that can measure the pressure exerted on a tissue by measuring the pressure of incompressible fluid filled in a rubber bag attached on the retractor. The compression test of gelatin was conducted with a constant compression speed. The pressure behavior initially increases nonlinearly with the deformation of the target, then becomes linear, and then becomes nonlinear with crack initiation. We developed a system that automatically detects the point where the system starts becoming linear. We also developed a smaller retractor to expand the range of application. The effectiveness of the system was confirmed through verification experiments using tofu and sheep brains.

The articles for daily use such as textiles, cosmetics, and home appliances are required to have pleasant tactile sensations. Sensory evaluation is used to evaluate the tactile sensation, but have problems such as individual differences among evaluators and low reproducibility. The purpose of this study is to develop new evaluation method to discriminate the tactile sensation by measuring the interaction between the finger and the object material. As a fundamental study, we measured the interaction between the probe and the material when touching four kinds of fabrics using an acceleration sensor, and investigated the possibility to discriminate the materials. The results of the frequency analysis of the acceleration of the touching motion by mechanical probe showed that the machine could discriminate the materials in the frequency range of 10 to 30 Hz.

A daily training helps fall prevention for elderly people. We develop a prototype of training support system that shows users training effectiveness using muscle motion analysis to keep motivation. Our system is composed of low cost stereo camera and muscle-skeletal modeling software. The joint coordinates are obtained from stereo camera images by image recognition. The muscle force and joint moment are estimated using inverse kinematics and inverse dynamics. In our system the problem is instability of coordinate in general stereo camera. We propose the coordinate correction based on the human body structure and the human movement. In our method the energy function based on two constraint is optimized to correct coordinates. The simulated data is corrected by our proposed method. The corrected coordinate is similar to true coordinate and the standard deviation of error is 15.9mm.

This study aims to estimate stiffness of the vastus lateralis muscle in quiet standing using a system identification technique. Six healthy males (age 22) participated the experiment. The electrical stimulation, monopolar rectangle pulse of 500 μs and approximately 30 mA, was applied to the vastus lateralis muscle. The electrically induced reaction force was measured with a force plate. The transfer function from the electrical stimulation to the induced reaction force was identified as the 5th-order model. The model consists of two 2nd-order models and one 1st-order model. One of the 2nd-oder model provided the muscle stiffness which was 630 to 1119 N/m.

This study estimated the stiffness of the medial gastrocnemius muscle and ankle joint by varying the ankle dorsiflexion angle. Six healthy young males participated in the experiment. An inclined plate was attached to the force plate. Each participant stood on the inclined plate, and his feet were dorsiflexed during quiet standing. Electrical stimulation was applied to the medial gastrocnemius muscle. The center of pressure (COP) was measured by the force plate. Measurement was performed at 0, 6, 10, and 15 degrees of the dorsiflexion angle. The COP fluctuation due to electrical stimulation was extracted using a Kalman filter. The transfer function from the stimulation to the fluctuation was calculated using a system identification method. The poles of the transfer function were used to estimate the muscle and joint stiffness. The muscle and joint stiffness decreased and then increased as the dorsiflexion angle increased.

It is generally known that 3D structures are required for cells to exert their function. Therefore, a method to produce large quantities of spheroids or organoids with stable size and quality is anticipated in regenerative medicine and R & D of drug using stem cells. Although various methods have been proposed for the production of spheroids or organoids, it is difficult to eliminate physical and chemical stimuli in all of these methods. The conventional methods have some problems such as a low collection rate, an expensive device, and a complicated process. We developed a new culture devise in which cells are detached from the scaffold with time, and then spheroidized even in the normal cell culture process. It is expected that spheroids can be produced easily with stable quality and the initial and operating costs are very low by using the devise.

We developed a scaffold to make spheroids and organoids easily by forming an extracellular matrix patterns on a substrate coated with fluororesin. The size of the pattern made with a microstamp must be accurately controlled in advance, to control size of the spheroids by this method. The shape of patterns is varied by the parallelism of the stamp with the substrate and the stamping load. Therefore, to improve the reproducibility of patterning, we made a device capable of controlling the parallelism and the load of the stamp. The parallel alignment of the substrate and the stamp was made possible by irradiating the bottom surface of the microstamp with light and reading the maximum value of the reflected light with a fiber sensor. The load was calculated from the deflection detected by the linear sensor. We report the improvement in reproducibility of extracellular matrix pattern size by using this device.

The major current treatment of the apical periodontitis had been cleaning of the root canal with chemicals and specialized equipment. Recently, electro-magnetic apical treatment called EMAT have been proposed. However, optimal conditions and sterilization mechanisms in treatment have not been clarified sufficiently. In this study, a device(Trench-type) was produced to apply a uniform current to the target bacterial suspensions for fundamental experiments. The simulation results confirmed that a device had a uniform current density. In addition, it was observed significant electro-sterilization effects in the experimental results. In the future, it is necessary to carry out comparative experiments between heat sterilization and electro-sterilization under precise temperature control.

Mesenchymal stem cell (MSC) is used in clinical application of regenerative cell therapy. However, MSCs deteriorate differentiation ability when mechanical memory of the substrate is accumulated in MSCs. Thus, cell culturing substrate that assure the undifferentiated state of MSCs is required. Since the intracellular stress is considered as the mechanosignal input of the substrate, the culturing substrate that causes the non-steady intracellular stress dynamics should prevent the accumulation of mechanical memory. In this study, by using the micro-elastically patterned hydrogels, we developed cell culture system that activates the fluctuation of intracellular stress. We showed that the fluctuations of the traction force and nuclear shape of MSCs on the triangular patterned gels were significantly larger than those on the homogeneous gels, which came from nomadic motion of the MSCs between soft and stiff regions.

Mutations of pendrin cause severe sensorineural hearing loss. In our previous study, we reported that salicylate restores localization and function of pendrin mutants and that its derivatives restore their localization. However, the effect of salicylate derivatives on function of pendrin has not been clarified. In the present study, a method using a solid-phase transfection for evaluating compounds was developed.An expression vector cording green fluorescent protein (GFP) was transfected to HEK293 cells by the conventional and solid-phase methods. After 24 hours, images were acquired using a fluorescence microscope. The total number of cells and the number of cells with GFP fluorescence were calculated by image analysis. As a result, the solid-phase method improved the cell viability by about 30% while maintain the same transfection efficiency of about 15% as the conventional method, suggesting that this method is useful as an evaluating system for compounds recovering the function of pendrin mutants.

Although reconstructive surgery using the patient's flap is performed to treat tongue cancer, it has been reported that dysgeusia and dysphagia occur. In order to overcome this problem, we developed the decellularized tongue as a scaffold to reconstruct the tongue with taste and swallowing functions. In this study, the decellularized tongues were prepared by rat tongues, and investigated by histological evaluation, residual DNA quantification, and SEM observation. The method of combination of freeze-thaw and sonication with a chemical treatment could prepare the decellularized tongues that meets the criteria for the amount of residual DNA. It was also cleared that the surface structure and ECM of the tongue epithelium differ depending on the decellularization methods. The prepared decellularized tongue will be evaluated by in vivo to clarify the effect of differences in extracellular matrix structure on tongue function reconstruction.

Zika virus (ZIKV) is transmitted by Aedes aegypti, and has an aspect of STD pathogen. Its intrauterine infection causes microcephaly. Envelope (E) protein induces protective immunity. The mucosa is the front - line to foreign substances and microorganisms, and a mucosal immune tissue called mucosal - associated lymphoid tissue (MALT) exists. Therefore, immunization onto the gastrointestinal mucosa is expected to induce strong mucosal immunity with the IgA antibody in the mucus even in the reproductive organs. Yeast is a microorganism that exists in human gastrointestinal tract. It is very safe and applicable as a host for the expression of recombinant proteins. Thus, using yeast as a vaccine antigen is promising. Therefore, in this study, we try to establish a yeast strain that expresses ZIKVE protein on the cell surface to use as a mucosal vaccine antigen that induces protective immunity to the genital mucosa by oral immunization.

Mesenchymal stem cells (MSCs) are adult stem cells that possess self-renewal and multi-lineage differentiation potentials. MSCs are considered an attractive source for regenerative medicine. To construct a graft for cell transplantation, we attempted to form a cylindrical MSCs construct using hollow fiber as a template. MSCs were seeded in EZSPHERE^TM plate to form spheroids. Then the collected spheroids were injected into the lumen of hollow fibers (Asahi Kasei Medical) and cultured to promote the formation of macroscale tissue-like constructs. After 1 day of culture, the cylindrical tissue constructs were formed inside hollow fibers. We could easily retrieve these robust cellular fibers from hollow fibers. Masson's trichrome staining showed abundant collagen deposition inside the tissue. The fiber-like MSCs tissue showed higher secretion activity of VEGF comparing that in monolayer culture.In summary, we established the method for the rapid formation of fiber-like MSCs construct.

The scaffold of the transparent film with micro pattern markers has been designed to measure the contractile movement of myotube under electric stimulation in vitro. The scaffold is made of a thin film (0.006 mm thickness), of which the rear side has arrangement of polydimethylsiloxane micro-protrusions (0.004 mm diameter, 0.002 mm height, interval 0.03 mm) made by the photolithography technique. Mouse myoblasts (C2C12) were cultured on the film for 12 days. The electric pulses (1 s pulse cycle, 1 ms pulse width) were applied between electrodes of titanium wire dipped in the medium. Through the transparent scaffold, the periodic contraction of the myotube was observed. The movement of the distance between the micro-markers depends on the long axis direction of the myotube and on the distance from the myotube. The designed scaffolds with micro-markers can be applied to the measurement of myotube contraction in vitro.

Osteocyte is a commander to modulate the bone remodeling. While studies in osteocyte differentiation are mainly performed in a conventional 2D condition, we fabricated 3D spheroids reconstructed by mouse pre-osteoblast cells in an ultra-low attachment plate. As a result, in the absence of chemical osteogenesis differentiation supplements, the osteocyte gene expressions in the spheroid were greatly up-regulated within 2-day, compared to the 2D monolayer. Similarly, spheroids reconstructed by pre-chondrocyte cells also exhibited the osteocyte-likeness. In addition, we introduced a 3D-to-2D model by transferring the 3D spheroids to a normal cell-adhesive dish. Eventually, it became 2D-like structure after dissociation. In the 3D-to-2D model, the up-regulated osteocyte gene expressions were recovered to the level of monolayer. The results indicated that the cell condensed condition for osteocyte precursor cells in the 3D spheroid culture triggered osteocyte differentiation. Those spheroids are expected to become a new in vitro model for osteocyte studies.

Cells and tissues in our body receive various mechanical stimuli, which play critical roles in promoting tissue maturation. Mechanical stimuli are applied on in vitro tissues aiming to promote maturation, yet a high level of tissue maturation has not been achieved. This is because the mechanism of tissue maturation has not yet proven. Therefore, it is anticipated to unravel the tissue maturation mechanism in detail and to find an optimal mechanical stimuli condition on tissues. In this research, a system for single-cell-resolution monitoring of three-dimensional tissue under mechanical stimuli is presented. The system is composed of linear motorized stages and a stage-top incubator and mountable on a microscope stage. It was proven that the constructed stretch and observation system successfully conducted the confocal imaging for more than 10 hours. The system can contribute to unravelling the mechanism of tissue maturation by mechanical stimuli in the future.