Body movement analysis is generally performed by using motion capture or inertial sensors. However, the validity of external sensors has long been a subject of debate because of the misalignment between the movement on the surface and that inside the skin. On the other hand, ultrasound echo has been attracted much attention in the clinical field. However, ultrasound echo can only observe the inside the skin, and it is difficult to analyze body movements by itself. In this study, with a focus on the behavior of the calcaneus, a device that measures inversion/eversion of the ankle angle using an inertial sensor and ultrasound echo is proposed. The effectiveness of this device was verified by measuring the inversion/eversion of the ankle angle in a foot-stamping experiment on five healthy male subjects in their 20s. The results showed a pattern of variation similar to that of the theory, confirming that there was no error in the measurement method. In addition, the maximum displacement of about 5 deg was observed in the angle measurement in the ultrasound images, demonstrating the necessity of the measurement inside the skin.
Virus detection methods based on nonlinear magnetic response of magnetic nanoparticles have been investigated, and magnetic detection methods using the third harmonic are widely applied, owing to their high sensitivity and short measurement time. This paper proposes a virus detection method based on the second harmonic because of its larger signal component. We found that the second harmonic signal is superior to the third harmonic signal for small nanobeads and a large change of the second harmonic signal in the signal-to-noise ratio (SNR) with nanobeads concentration. In addition, a virus detection limit of 100 pg/ml is achieved. Therefore, the proposed method can potentially be utilized for rapid screening of viruses.
Inducing proper ankle joint alignment at heel contact is important in the gait cycle in terms of smooth weight transfer and reduced burden on the knees and hips. Therefore, the insole-type device that makes the ankle angle neutral during heel contact was developed. However, the backlash in the drive mechanism caused a rattling during heel contact, resulting in the accuracy of the control angle and discomfort issues. In this study, we propose the insole-type walking support device equipped with a control method to eliminate rattling. The validation of effectiveness was conducted through functionality and durability experiments, and it was confirmed that the ankle angle could be controlled within 375ms with an accuracy of 0.1deg or less, and that there were no durability problems. In addition, a foot-stamping experiment with one healthy male showed that use of the device improved knee alignment.
Magnetic hyperthermia with magnetic nanoparticles (MNPs) has been introduced to selective treatment of tumor and the MNPs also has demonstrated diagnosis. For non-invasive treatment, a therapeutic platform with temperature monitoring that can avoid overheating in normal tissues is of vital importance. In this study, we have developed a wireless temperature monitoring system by utilizing the combination of magnetic harmonic signals of the MNPs for magnetic hyperthermia treatment in laboratory experiments. We achieved an accurate measurement with an error of 0.18 °C. For practical use on breast/oral cancer, a detectable distance of at least 10 mm is required. To demonstrate the feasibility toward future biomedical applications, we investigated the dependency on the amount of Resovist® and the error is less than 0.5 °C in a 10 mm distance. Our system can measure the correct temperature regardless of Resovist amount. The results indicate that our system can apply for monitoring temperature on magnetic hyperthermia treatment.
