Magnetic nanoparticles have attracted attention for biomedical applications such as hyperthermia treatment magnetic particle imaging for cancer theranostics. Magnetization dynamics in magnetic nanoparticles determined by the particle structure, applied magnetic field, and surroundings were important for the efficacy of heat generation and signal for magnetic particle imaging. The hysteresis in magnetization response qualified from the area of magnetization curve under an alternating magnetic field was proportional to the heat dissipation. The non-linear response of the magnetization toward the applied magnetic field generated the harmonic magnetization signal. For hyperthermia using magnetic nanoparticles, it is necessary to develop the particle design to enhance the hysteresis derived from the phase delay from the applied magnetic field whose amplitude and frequency were limited considering the safety for the human body. To increase the sensitivity and spatial resolution in magnetic particle imaging, the strongly non-linear magnetization, large gradient magnetic field to select the field free point in the field of view, sensing device, and analytical approach were developed. Moreover, the combination of hyperthermia and magnetic particle imaging was investigated for low invasive and early theranostics.

This paper reviews non-invasive brain stimulation using electromagnetic fields, particularly for the treatment of mental disorders such as depression. Transcranial magnetic stimulation (TMS) and temporal interference (TI) stimulation could be alternatives to conventional electroconvulsive therapy. A recent study showed that the design of TMS coils has been optimized for deeper brain penetration while maintaining focality. In addition, TI stimulation has the ability to selectively target deep brain regions. These findings contribute to the development of effective, non-invasive neuromodulation therapies that may improve outcomes for drug-resistant patients.

The purpose of this paper is quantitative evaluation of guiding control by magnetic guiding device for capsule endoscope (CE). In this report, the magnetic force for a CE manipulating a magnetic guiding device is calculated using a transient response analysis with a finite element analysis software. It was found that the maximum value of magnetic force is defined by the distance between the CE and the magnetic guide device. This paper proposes an approximation for the maximum value as a function of the distance if the distance is between 0.06 m and 0.12 m. From experimental results, the guide control by magnetic guide device is successfully confirmed at the distance of 100 mm. It is noted that the movement speed of the magnetic guide device should be less than 0.066 m/s.

This paper deals with further miniaturization of magnetically driven flapping pico air vehicle. Its flapping mechanism consists of a wing film attached to a torsion spring with a permanent magnet, and can be driven by an external alternating magnetic field. Our previous research has suggested that it is effective to match the resonant frequencies of the flapping motion and the bending vibration of the wing film to increase thrust. In this study, we conducted experiments by changing the wing material and magnet size to confirm whether this design guideline can be applied to short wing length. As a result, we confirmed that the design guideline is effective even with short wing length of 3 to 4 mm, and flight is possible with a minimum span of 12 mm.

The pitch of human whistling corresponds to the resonant frequency of the vocal tract, with the corresponding resonance referred to as a register. However, many aspects of register in human whistling are unclear. In this study, we developed vocal tract models based on magnetic resonance imaging data of the vocal tract while producing two types of whistles with different registers. We then examined the feasibility of identifying the register using the model while analyzing differences in vocal tract shape. The results confirm that the vocal tract shapes differ and that registers can be estimated using this model.

This study shows a new electric field conversion method for the response waveform of radiated electric field with a Vivaldi antenna due to ESD between 500 V charged metal spheres, as conducted by Pommerenke and his group. The method employs the rate of the theoretical peak electric field, derived from the Rompe-Weizel spark resistance law, to the peak of the antenna response as a constant antenna factor.