Using transcranial direct-current stimulation (tDCS) combined with a complex multisensory-motor dance video game (DVG) task, we investigated a possible role of the middle temporal gyrus (MTG), an integration site of visual and auditory information, on the motor learning efficiency. Eighteen young-adults received any one stimulation type of anodal, cathodal, or sham stimulation and performed DVG for 3 times. The number of timing-accurate steps was evaluated as an index of motor performance over repetitive game play and stimulation conditions. Anodal MTG stimulation increased the post-training performance selectively in participants who had previous experience of musical training or music video game, whereas cathodal MTG stimulation increased the post-training performance in the other novice participants. These results demonstrated differential effect of MTG stimulation on the improvement of timing accuracy in DVG task depending on the previous experience in multisensory-integrative motor task.
We have studied about an EMG analysis system for an electric prosthetic forearm control. Our previous experiment for motion recognition yielded high recognition accuracy results. This experiment with the 48-channel EMG system used Monte Carlo Method to decide sensing electrode position, and linear discriminant analysis. And, we have found when four channel electrodes are attached to correct positions on the forearm, it is able to recognize motions of it. This objective of this study is the development of a wearable the four-channel EMG analysis system by using our previous experimental results. Therefore, we have done motion recognition experiment, to confirm that obtain high recognition accuracy even if 4-channel EMG system sensing at electrode positions determined by 48-channel EMG system. In conclusion, the present study has demonstrated that high recognition accuracy requires training for using EMG system, and we found out sufficient training period depend on examinee.
Myoelectric upper limb prosthesis has some problems such as its stability of contact condition or determination of the optimum position of electrodes. This study reports the Development of a socket integrated with array electrode for myoelectric upper limb prosthesis. This array electrode, which was made of conductive cloth, can cope with various shapes of stumps of amputees. The advanced socket integrated with the developed array electrodes has capabilities to determine the appropriate positions of electrodes without much considering the location. The prototype is valid for detecting EMG signals for the control of myoelectric upper limb prosthesis.
In this paper, a method of simple geometrical analysis method during ankle joint stretching treatment using numerical calculation was proposed. The stretching of the ankle joint is an important medical treatment that physical therapist (PT's) help their patients to recover their ability to walk and to prevent contracture. Since the ankle treatment requires a large amount of force (nearly equal to the subject's weight) and precise angle control at the same time, manual treatment by PTs has not been replaced by mechanical treatment systems and the mechanism of the treatment has not been analyzed mathematically. In order to realize developing the effective mechanism of the treatment, numerical calculation analyze the geometrical relationships between Ankle joint, Hip joint, Thenar and pushing device rotation center during the treatment. The proposed numerical calculation method will effectively work to develop the mechanical systems of ankle joint stretching treatment. of proceedings paper for the 56th Conference of Japanese Society for Medical and Biological.
This study investigates the temporal relation between the presence of recall question and stride length under dual-task walk using autoregressive exogenous (ARX) model. The ARX model is developed to estimate the response of stride length during the dualtalk walk. Each stride length is measured by a toe-mounted inertial sensor. Ninety elderly subjects performed a recall question like the names of Japanese prefectures during 50 [m] walk, and eleven younger ones performed a more difficult task during 100 [m] walk. Most of step responses estimated by ARX model showed the local minimum value in the stride length immediately after the start of recall question. The time from the start of recall question to the local minimum is around 2.5 [s] and has no significance between elderly subjects (n=23) and younger ones (n=8). The recall question while walk causes rapid decrease in stride length and may increase of risk of fall.
This study proposes a chest sound-based wearable device for respiratory measuring and the monitoring of asthma. For the proper diagnosing and follow-up, measuring the respiratory is important when symptoms of asthma appear. The symptoms are convulsive, although asthma is a chronic disease. The symptoms could appear when the patients are in their homes or outdoor, so the proper finding of their severity is difficult. The main challenge here is the respiratory phase identification because of the high level of distortions to the signals from the artefacts during spontaneous breathing. To overcome this challenge and realize high noise stability, both the respiratory sound and the chest movements are used. To measure the chest movements, this device is formed from a flexible material. The results of a preliminary experiment and a phase identification experiment show the characteristics of signals and the possibility of identification by using proposed device.
Deep learning methods such as the Convolutional Neural Network and the Residual Network were applied to CT scan images in order to classify whether lung nodules become cancerous or not. Especially, the effect of changing the number of layers in the Residual Network was. Experiment were carried out using several models having these two network architectures and consisting of different numbers of layers and parameters.
In recent years, computational fluid dynamics (CFD) has been used for designing rotary blood pumps. The secondary flow in the pump, especially between the blades, can be simulated by CFD and more precise prediction of pump performance at design and offdesign points can be made. The US Food and Drug Administration (FDA) is engaged in establishing guidelines for the usage of CFD in the research and development phase of medical devices in order to help speed up the FDA approval process. The utilization of CFD is expected to increase further. In this study, we designed an axial flow blood pump and the flow field within the pump was calculated by CFD analysis. It was confirmed that the pump performance was suitable for right heart assistance.
The influence of Active Noise Control (ANC) on auditory impression for listening to music other than noise was observed by psychometric measurement and Magnetoencephalography (MEG) measurement in a situation where both noise and sound off-target sounds were mixed. For the stimulus sound, five situations under kinds of sounds, with or without one before noise reduction and one with noise reduction by ANC, were set created for three kinds of each music. In the psychological measurement, the effectiveness adverse effect of ANC was observed in the case of music with the lowest spectral center of gravity. In the MEG measurement, the effective duration of the ACF, τe , of MEG in the 20-50 Hz range, was employed represents and it lengthened for preference stimuli.
The evaluation of subjective impressions induced by environmental sounds using neurophysiological indices has been proposed in recent years. In this paper, we focus on the evaluation of HVAC (heating, ventilation and air conditioning) sounds, and models that predict subjective coolness/preference induced by time-varying HVAC sound from brain activities were constructed. First, magnetoencephalographic (MEG) measurements were carried out to measure brain activities while hearing HVAC sound with paired comparison task. Second, feature vectors representing time-frequency components of brain activities on the whole head were extracted from MEG data using the time-frequency analysis and nonnegative tensor factorization (NTF). And third, two kinds of predictive model were constructed from the brain feature vectors and comparative judgments to pairs of stimuli using a regression model or an SVM-based method. Evaluation experiments show that the SVM-based method is more effective than the regression model.
Background: Intraoperative neuromonitoring has been introduced to such surgery as head and neck, however, it is insufficient to predict the nerve function. In this study, we evaluate the nerve function by measuring the action potential directory in the operation field.
Methods: Sciatic nerves of the rabbits were pulse stimulated electrically. The amplitude of the action potential of the nerve was evaluated on the nerve or surrounding tissue using by a custom-designed bio-amplifier.
Results: Two different waveforms of electrotonic spread and the saltatory conduction were recorded. The conduction velocity was 50 to 60 m/s. The amplitude of saltatory conduction on the nerve and surrounding tissue was measured approximately.
Discussion: The saltatory conduction in the neighboring tissue was evaluated. It makes possible to detect the action potential derived from the nerve within 10 mm away from the nerve in the operative field.
We used dance video game (DVG) training as a mean of improving elderly's cognitive function and investigated whether the elderly with MCI could overcome the once affected cognitive function via continuous DVG training. Nine elderly participated in 6-weeks of DVG training for almost 3 months on 2015 and 2016 with 6 months break. Their cognitive ability (MoCA-J scores) and the prefrontal activity during DVG play were evaluated throughout the intervention. The cognitive ability and the performance of the DVG showed improvement especially in the elderly with MCI. The prefrontal activity showed increase through initial training of DVG and decrease at the end of the intervention, suggesting the cognitive load required for DVG play. Our results suggest that DVG is a promising intervention for elderly people with MCI to maintain their cognitive ability, and that we can utilize the prefrontal activity during DVG play to determine an appropriate difficulty of the DVG training.
When the lesion progresses in living tissue, the hardness of the tissue changes. Therefore, quantitative measurement of tissue hardness is required. In this study, the object is vibrated by dual acoustic radiation pressure. We aim to estimate viscoelastic properties by examining the frequency response of the tissue. In this report, we observed the change in the displacement amplitude of the object by changing the oscillating frequency. As a result, it was found that the displacement amplitude becomes smaller as the frequency is set higher. It was confirmed that it decreases with a slope of -40dB/decade between 10 Hz and 200 Hz. This phenomenon is thought to be due to stress relaxation. We will clarify frequency characteristics from stress relaxation function.
The natural frequencies of the longitudinal and radial directions of the biceps brachii muscle were estimated by measuring evoked torque and muscle oscillation, respectively. The purpose of this study is to reveal the relation between the natural frequencies of longitudinal and radial directions to the biceps brachii muscle. An electrically stimulated evoked torque and mechanically stimulated evoked muscle oscillation were measured with a strain gauge load cell and myotonometer, respectively. The measurement was carried out during a resting state and an isometric contraction. The systems of the evoked torque and the muscle oscillation were identified. The natural frequency of the systems was calculated from the poles of the transfer function. In conclusion, the frequency of evoked torque and muscle oscillation increased as the muscle contraction level increased. It is suggested that the natural frequency of the axial direction might be estimated from the natural frequency of the radial direction of the muscle.
The purpose of this study is to clarify the relationship between gastrocnemius muscle stiffness and gait speed. Eight males participated in this experiment and walked at 2, 3, 4, and 5 km/h on a treadmill. Electrical stimulation was percutaneously applied to the medial gastrocnemius muscle once every two push offs, and the mechanomyogram was measured. The evoked mechanomyogram was extracted by subtracting the walking vibration from the measured mechanomyogram. The evoked mechanomyogram system was identified using a singular value decomposition method, and the natural frequency was calculated from the transfer function. The natural frequency was used as an index of stiffness. Two natural frequencies increased as gait speed increased; however, one natural frequency did not. The increased natural frequencies might be related to the muscle contraction, and the unchanged frequency might be related to the skin and subcutaneous tissue. In conclusion, medial gastrocnemius muscle stiffness increased as gait speed increased.
An ensemble averaging of frequency spectrum of biosignal corresponds to a smoothing of frequency spectrum obtained by Fourier transform of entire signal. As a general rule, a variation of frequency spectrum obtained by an ensemble averaging of signals becomes small, therefore, a spectrum becomes smooth by an increasing of segment number. On the other hand, a decrease of number of data per segment under dividing signals into a plurality of segments decreases a frequency resolution. Therefore, an ensemble averaging which is balanced between spectrum smoothness and frequency resolution is desirable. However, there is no definite method to determine both a segment number and a segment overlap ratio, which are parameters in ensemble averaging of frequency spectrum. In this study, we propose a method to determine these two parameters in surface electromyogram using breakpoint. Also, we present experimental results that were applied our method to surface electromyogram.
The damage to health by the smoking is thought to be a severe problem. So the messages or images that show the risk with the smoking are printed on the packages of cigarette all over the world. The package design called “plain package” was defined by the law in order to reduce the consumption of the cigarette in Australia in 2012. Making the image for quitting smoking which has a certain effect is important to promoting healthy society. In this study, we investigated the effect of quitting smoking of plain package and conventional package based on brain activity. Results showed conventional package activated the orbitofrontal cortex which relate to the smoking desire. On the other hand, plain package activated the primary somatic sensation field related the sense of pain recognition. This result shows the possibility that plain package strongly reminded subjects of a risk of continuing smoking.
It is well known that the carbon emits far infrared rays (FIR). FIR has a thermal effect and it is widely used for heater and widely applied in medicine, including the treatment of chronic fatigue syndrome, chronic pain, and wound healing. Sericite, which emits FIR, has been used in the medical field to promote health and there are numerous reports that show beds made from sericite ceramics help relieve dysmenorrheic pain. So the carbonaceous personal ornaments may have good effect to improve the human physiological and psychological state. In this study, we investigated the physiological and psychological effect of the carbonaceous personal ornaments, glasses and watch (made by OHGI TECHNOLOGICAL CREATION CO.,LTD.) by comparing them with conventional ones, based on EEG, visual analog scale (VAS) questioner, etc. As a result, it was shown that the carbonaceous personal ornaments has significant effect of decreasing stress level and decreasing tension-anxiety level.
Intravascular surgery, such as coil embolization and stent placement, has been widely performed for treatment of cerebral aneurysms. Doctors must be skillful and sufficiently experienced to successfully manipulate and insert a guidewire and a catheter into the aneurysm via carotid and cerebral artery. Though blood vessel model is useful for training of the doctors in the field of the intravascular surgery, evaluation of doctor's skill and efficacy of training is insufficient. In this study, an ultrasound sensor was fabricated and equipped in the cerebral blood vessel model to measure the displacement of the vessel wall that is contacted and pushed by a guidewire or a catheter. It is confirmed that the fabricated ultrasound sensor could measure the displacement of blood vessel wall by the inserted catheter.
Nowadays, a variety of vital sensing devices have been able to be easily and inexpensively connected to any smart phones by means of wireless technologies. Typical examples of such wireless tools are Bluetooth, Zigbee, WiFi and WiSUN, which are all based on the IEEE 802 standard families. This paper shows the current status of the IEEE 802 standardization activities related to the support of everyday healthcare and medicine, such as the working groups of the IEEE 802.15.1, 802.11, and 802.15.4g. In addition, it introduces the IEEE 802.15.6 standards for supporting highly reliable wireless communications, which is required for providing medical and healthcare services.
Healthcare IoT is a new trend in the field of the next generation medical/healthcare services. A daily healthcare checking by seamless vital data collections using vital sensors combining with high level data analysis is one of the key services that the healthcare IoT can provide with users. In order to realize this service, a seamless and unconscious data collection method is an important technology. SmartBAN technology that has been standardizing in ETSI is suitable for a low-power and seamless vital data collection method. In this presentation, we present the update of SmartBAN and its challenges for the next generation medical/healthcare services.
We constructed a 3-compartment pharmacokinetic model for canine consisted of three compartments including plasma, interstitial space, and cell to estimate talaporfin sodium concentration change in interstitial space. Photosensitization reaction is performed when talaporfin sodium distributes in the interstitial space employing a short drug-light interval in our arrhythmia ablation. We studied interstitial concentration constructing the 3-compartment numerical model using talaporfin sodium concentration in canine plasma, and in addition, other measured relative concentrations of canine tissue, including plasma, interstitial space and cell information. We represented differential rate equation of the drug concentration in each compartment. Fitting the measured data set to the calculated concentration in each compartment, the rate constants in the constructed 3-compartment model were determined with R2=0.98. Using the 3-compartment model, the interstitial talaporfin sodium concentration and the available condition in our arrhythmia ablation could be estimated.
This paper presents an automatic sleep quality assessment method based on an unobtrusive sleep monitoring system, which comprises mainly of a bed sensor monitoring heart rate, respiratory rate, body movement during sleeping and leaving the bed, and a cloud system processing the daily sleep data. The data obtained during sleep are further derived to mine features and pattern of sleep so that it can be used to rate the sleep from a predefined scale. Six subjects were employed to evaluate the validity of the proposed sleep quality assessment method. Experimental results preliminarily show that the consistency and validity of our method comparing to the reference Pittsburgh sleep quality index (PSQI), which is a traditional sleep quality assessment method.
In previous studies, it was shown that the working memory of musician renews faster and has larger capacity compared with it of non-musician. However, the kind of musical skill related working memory was not clear. In this study, we investigated the relationship between several musical skills and working memory ability measured by EEG. As a result, it was shown that the significant positive correlation between P300 amplitude evoked by sound stimulus and absolute pitch for chord. It was also shown that the significant negative correlation between P300 peak latency evoked by image stimulus and sing at sight. On the other hand, the significant positive correlation between P300 peak latency evoked by image stimulus and relative pitch for chord was shown. This result contradicts former two results. This contradiction may be caused by small number of subjects. As a future study, we plan to apply more subjects.
We developed a low-cost, event-related desynchronization (ERD) measurement system using consumer-grade EEG system (Emotiv Epoc) for application of motor-imagery (MI) related brain machine interface (BMI). We investigated accuracy of ERD power detection of Epoc by comparing the ERD power calculated from simultaneously recorded EEG via Epoc and medical-grade EEG system (g.USBamp: g.tec medical engineering). Eleven healthy participants performed MI of holding a rolling tennis ball and opening the grasped hand under the observation of hand movement video. The mean ERD power was comparable between Epoc and g. USBamp with both hand gestures tested. ERD detection accuracy of Epoc was 70.5% of the all trials tested. Considering the price of Epoc, our results suggest that Epoc could be a good substitute for medical-grade EEG systems for the purpose of MI-based BMI.
It is the prerequisite for outpatients to go home after receiving medical care smoothly and safely. The most complicated consultation flow of outpatients is thought in the ophthalmology outpatient department. The reasons are listed as follows: Patient flow is complicated, almost of outpatients are elderly people, and outpatients with abnormal vision are forced movement in such complicated consultation flow. In the present study, we evaluated the enabling effect of the smartphones and tablet devices on the issues described above, changing a from of the nursing service, and the merits of outpatients.
We are developing Digital Mirror Box (DMB), a brain machine interface (BMI)- based rehabilitation system for stroke patients with hand paralysis. Aiming to train the motor-command generation from the affected hemisphere, DMB uses an event related desynchronization (ERD) derived from motor imagery as an operating signal of the BMI feedback. In order to assist the patients to perform motor imagery, the current DMB system presents a movie of hand motion, in which a hand-grasping motion picture is presented immediately after a still image of the fixation point. However, there remains a possibility that the detected ERD is influenced by an attentional switching from still to motion picture, not by action observation or motor imagery per se. We therefore modified the movie to contain a still image of a resting hand between fixation cue and hand motion picture. We could successfully differentiate the μ band suppression of the attentional switching from those derived from motor imagery.
We investigated the transition of event-related desynchronization (ERD) intensity through 6 days of brain-machine interface (BMI) training using Digital Mirror Box (DMB), which is a potential rehabilitation system for stroke patients with hand paralysis. Eleven healthy participants performed motor-imagery of grasping their dominant hand under the observation of hand movement video. The overall ERD strength of all participants showed a significant increase from day 1 to day 6. When the participants were divided into high and low ERD groups by their initial ERD strength of higher or lower than 0% at the initial measurement before BMI training, respectively, participants in low ERD group showed larger training effect. These results suggest that BMI training is particularly useful for increasing the ERD strength of stroke patients who have lower ERD strength.
In this report, development of a stressor evaluation system with image conversation comparing our formerly developed system with onomatopoeia was described. It is thought that stress reduction is possible by grasping eustressors and by doing aggressive coping. By such a principle, we have already developed the system which grasped these eustressors. And it was revealed that continuation of the use of the system was important to take the coping action. By the way, "image conversation" is a communication style of the mobile phone using images such as "emoji (emoticon)" or "LINE's stamps". Before we assumed the character (onomatopoeia) input with the mobile phone in consideration of convenience, but, by the spread of so-called smartphones, we hypothesized that the communication using images was simpler and easier. The results showed this image conversation system was much better than the onomatopoeia system from the questionnaires of 17 volunteers (21.82±1.38Y of 15 male and 2 female) in 7 days trial.
New Orange Plan proposed by Ministry of Health, Labor and Welfare shows the direction of care for the elderly with dementia should be done at their houses. In this presentation, needs of cooperation between medical care and nursing care of dementia patients living in their houses are analyzed and discussed about the information technology in the future.
To investigate nerve injury by a photosensitization reaction ex vivo, we observed an uptake of talaporfin sodium into crayfish nerve and porcine phrenic nerve, and measured electrophysiological conduction velocity of the crayfish nerve during the reaction. We found the drug uptake of inside the perineurium was lower than that of outside in porcine phrenic nerve. The crayfish nerve was immersed into 20 μg/ml talaporfin sodium for 15 min and irradiated by a 663 nm laser light with 120 mW/cm2. Since we found the measured conduction velocity was decreased increasing the irradiation time, the nerve might not be resistant to the photosensitization reaction at atmospheric oxygen environment. It was reported that the phrenic nerve was intact when an electro blockade using photosensitization reaction was performed in vivo animal experiment. Low uptake of talaporfin sodium inside the perineurium and low oxygen partial pressure of nerve might be the mechanism to preserve phrenic nerve in vivo animal experiment.
Morbidity causes abnormality in concentration of specific protein. Serum protein fraction method has been utilized for understanding the disease state from fractioned concentration ratio of protein after fractionating serum protein by electrophoresis. However, in the process of protein visualization, the staining solution currently used contains harmful substances to human body. Therefore, we focused on Terahertz (THz) wave which is harmless and absorbed by biomaterials. We have reported that proteins fractionated by Cellulose Acetate (CA) membrane electrophoresis can be visualized by absorption of THz wave. However, the obtained THz absorption image had low contrast, and the appearing band was also unclear. Therefore, in this report we constructed a coating method for CA membrane using material printer and a drying method after electrophoresis, evaluated the images obtained from the constructed methods. In addition, we examined an image processing method for extracting protein bands after reducing background noise of the image.
Flow generation techniques using surface acoustic wave (SAW) have been developed. This technique is useful for the mixing/separation of particles in a small droplet and can be applied for the laboratory testing with extremely small amount of specimen. In this study, a hemispherical shaped micro water droplet with a volume of 30 μL was modeled and the SAW-driven flow in the droplet was numerically calculated. The calculation results show that a vortex generated around the SAW irradiation site moves toward the droplet center and it derives upward flow. The particles with the same degree as the density of water follows the flow field in the droplet and eventually pile on the peripheral area. The particles with high density moves toward the droplet center along the substrate surface and accumulate at the central area. The feasibility of cell separation was confirmed from the numerical simulations.
We formed aggregates with microbubbles attached around cells, and developed a technology to transport cells in the blood stream by using ultrasound apply to immunotherapy. Though we reported displacement and sustainability of aggregates by traveling wave, in this study we have manipulated aggregates by moving acoustic distribution. The nodes of standing wave were moved within the view and aggregates were tracked by image processing. When nodes swept at 20 μm/ s , aggregate moved at a rate of 30 to 60% respect to the sweep speed. Similar measurements also applied to T-cells, confirming that the kinetics could be controlled. Compared with the method of the previous study at high sound pressure, destruction of micro bubbles can be suppressed and the controllable duration time has been improved to over 30 s. It showed that the movement of acoustic distribution enable to control the dynamics of aggregates for a long time.
I measured the magnetic fields produced by human brain and studied about function of the brain in the magnetic laboratory in MIT. After I came back to Japan, I developed new measurement system for the magnetic fields produced by human brain and studied about function of the brain.
Possible contributions of biomagnetics and bioimaging to child rearing are discussed. Scientific approaches to child rearing are important to keep and improve a high quality and affectionate rearing of children in house and in society. Philosophy and essences of way of thinking of great person are referred, and potential bridges are tried to construct between child rearing and engineering mainly based on magnetic brain stimulation and imaging. The essences for child rearing and education are referred to Emile by Jean-Jacques Rousseau, education of Helen Keller by Anne Sullivan, and quotes by Mother Teresa. In biomagnetics, magnetic brain stimulation or transcranial magnetic stimulation (TMS), magnetoencephalography (MEG), magnetic resonance imaging (MRI), functional MRI, magnetic control of cell growth, and other potential therapeutic applications of magnetic techniques are introduced. Recent neurosciences such as reward circuit and default mode network are briefly discussed for potential bridges between child rearing and brain research.
Mechanical stimuli by a probe were applied to myocardial cell aggregates in vitro. The stimulus was given periodically and its motion was mimicking the actual contraction-relaxation motion of spontaneous beating by a cell aggregate. We investigated the effect of the external stimuli on spontaneous beating of cell aggregates in short-term at room temperature and in long-term under culture conditions. At room temperature, myocardial cell aggregates were sensitive to the stimuli and the aggregate's spontaneous interbeat interval (IBI) dramatically changed in time. In contrast, the long-term periodic stimuli tended aggregates to synchronize their beating with the stimulus frequencies by 24h. Finally, we would discuss the biological responses under long-term mechanical stimuli in culture conditions.
This paper reports on a capacitor divided microcoil as high sensitive MRI (Magnetic Resonance Imaging). A capacitor divided microcoil was fabricated by assembling 3D printed structures and planar coil wirings fabricated by MEMS (Micro Electro Mechanical Systems) technology. Since a capacitor was inserted into the coil wirings, this microcoil has high self-resonant frequency. The number of turns, diameter and length of the coil were 12, 12 mm and 16 mm, respectively. Since the capacitor divided microcoil has high selfresonant frequency, we acquired clear MRI image of the cooking oil.
We have proposed a noninvasive technique to observe an arteriovenous fistula using an optical transillumination image of a blood vessel. To improve the accuracy of inner-diameter measurement of the vessel, we examined the effectiveness of the imagesubtraction technique using multi-wavelength light sources. In the experiment, we fabricated a model-phantom to simulate a human forearm. It contained the tube filled with replaceable absorber liquid which simulated the blood in different wavelengths of illuminating light. The transillumination images of the blood column were recorded with the liquid of different absorption coefficients. The imagesubtraction technique was applied and the images were analyzed. With the subtraction, the sharpness of the column image was improved by 55%, and the error in the diameter measurement was reduced from 28% to 4%. This result verified the effectiveness of the image-subtraction to promote the clinical application of the proposed technique for the controlled care of the arteriovenous fistula.
An optical fiber probe for measurement of water content of oral mucosa is proposed. The probe is composed of silica optical fibers to radiate white light and fibers for detection of diffusely reflected light from the sample. Firstly, by experiment using gelatin film, it is confirmed that the intensity of absorption peak of water at 1450-nm wavelength linearly increases with water content. As a result of in-vivo experiment using human tongue as a sample, it is shown that water content can be measured by the diffuse reflectance detected by the proposed method.
Slicing sample preparation in tissue optical characteristic measurement may makes huge error over individual optical differences. We proposed the combination of light intensity measurement through an optical fiber puncturing into a bulk tissue varying detection numerical aperture and ray tracing calculation to avoid slicing degradation of living tissue. To reveal the characteristics of this measurement, optical coefficients of pig myocardium obtained by the IAD method with slicing living tissue sample preparation and proposed measurement method were compared. In the proposed method, a silica fiber installed in an18G needle was punctured up to the bottom of the myocardial bulk tissue to measure light intensity in the bulk tissue changing depth and numerical aperture. The author found that measured apparent attenuation coefficients tended to strongly depend on numerical aperture. The ray trace calculation explained the same numerical aperture tendency in above mentioned experimental result. Optical characteristics of sliced myocardial samples revealed temporal change due to dehydration.
For early detection of disorder in the vascular endothelial function, a technique to evaluate the viscoelastic characteristic of the vascular wall was developed by measuring the blood pressure of the radial artery and measuring the change of the vessel diameter at a different close position. By it measurement, however, an accurate evaluation of the viscoelastic characteristic is difficult due to the small time lag between the waveforms. Therefore, for measuring both the blood pressure and the change of the vessel diameter at the same position, the present study presents a new method to acquire the blood pressure by the same ultrasonic probe as that for the ultrasonic measurement of the change of the vessel diameter. From the resultant waveforms, the hysteresis characteristic of the vessel diameter was obtained in in vivo experiments.
Motivation: Over the past few years, activity trackers which can measure everyday steps, energy expenditures, and sleeping time are getting popular. Especially these days, some activity trackers use not only accelerometers but also optical heart rate monitors based on photopletysmography. In this study, we evaluated reliability of an optical heart rate activity tracker during running.
Method and Results: Several subjects(n=11, all male) ran 1km on a flat road and we analyzed heart rate errors to check if there was a difference between subjects. We found that some subjects had significantly higher Mean Absolute Error than others(highest MAE,20.54±13.64; average MAE, 8.41±6.47), and there was a strong correlation between each subject's MAE and the standard deviation of running speed(Pearson's r=0.87, p<0.001).
Conclusion: Optical HR monitors lead to errors when users change their pace of running.
The extension of healthy life expectancy is of high concern these days. Keeping some functions above a certain level is necessary for body activities, like muscular skeleton system, respirator circulation system and nervous system. Although function aging may be unavoidable, through analyzing their quantity, body age can be inferred, furthermore getting body age younger through specific functional exercise may become possible. One kind of total body scoring technology is used to calculate the body age of 42 managers and executives of one corporate, and 16 body items are measured. It is based on research about relationships of 430 body items collected from three-dimensional body scan, CT and blood analysis etc. The result shows average body age 39 versus real age 52. However, they are almost same for various people in public society. So, it is speculated that employees promoted above management level are better at self-management about health.
Bone is often regarded as a composite material consisting of mineral particles and organic matrix (mostly Type I collagen) on a microscopic scale. The mechanical properties of bone tissues at a macroscopic scale depend on the structural organization and properties of constituents in the microscopic scale. It is the interaction between the mineral and organic material that determines the mechanical properties. However, both mechanical behaviors of mineral and collagen phases are not clear yet. In this study, to clear both mechanical behaviors of collagen matrix and apatite crystals in bone, the cortical bone samples were collect from bovine femoral diaphysis. The microscopic mechanical behaviors of both mineral particles of apatite and collagen matrix in bone tissues were observed by wide angle X-ray diffraction (WAXD) and small angle X-ray scattering (SAXS), respectively. In combination with micro-tensile device, both strains of mineral and collagen phases were measured.
This is a preliminary study of abnormal heart beat detection using non-contact electrocardiograph (NcECG). The NcECG has 3 strips of electrodes placed on bed, with its positive electrode at the buttocks, negative electrode at the shoulder blades and earth at the waist. Two subjects were recruited for a 40 minutes measurement. Raw signal was filtered with a band pass filter [1-40 Hz] and R peaks were located by thresholding. Limb lead ECG detected the arrhythmia of one subject and we were able to detect 1146 heartbeats out of 1162 heartbeats for 14 minutes stable measurement. For the other subject, the signal could be measured stably for 20 minutes. For the whole 1396 heartbeats, 1393 heartbeats could be detected. Although signal was influenced by body movement, P, T waves may also be picked up. By neural network etc., abnormal heart beats might be detected instantly with NcECG.