The second most common progressive neurodegenerative disorder, Parkinson’s disease (PD), is characterized by a broad spectrum of symptoms that are associated with its progression. Several studies have attempted to classify PD according to its clinical manifestations and establish objective biomarkers for early diagnosis and for predicting the prognosis of the disease. Recent comprehensive research on the classification of PD using clinical phenotypes has included factors such as dominance, severity, and prognosis of motor and non-motor symptoms and biomarkers. Additionally, neuroimaging studies have attempted to reveal the pathological substrate for motor symptoms. Genetic and transcriptomic studies have contributed to our understanding of the underlying molecular pathogenic mechanisms and provided a basis for classifying PD. Moreover, an understanding of the heterogeneity of clinical manifestations in PD is required for a personalized medicine approach. Herein, we discuss the possible subtypes of PD based on clinical features, neuroimaging, and biomarkers for developing personalized medicine for PD. In addition, we conduct a preliminary clustering using gait features for subtyping PD. We believe that subtyping may facilitate the development of therapeutic strategies for PD.

We present a recently developed shimming method that uses a system of room-temperature (RT) orthogonal shimming coils to improve the spatial field homogeneity of high-resolution nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) superconducting magnets. Conventional RT shimming methods require recursive routines of field mapping and RT shim coil current adjustments, which lead to a less effective and time-consuming process. In this paper, we introduce a new RT shimming method that utilizes a process of gradual and automatic search to find an optimal operating point with a genetic algorithm (GA), a type of optimization technique. The proposed algorithm is capable of determining the optimal set of currents for a system of shimming coils to create the best spatial field homogeneity by minimizing the NMR spectral linewidth. We used a commercial 600-MHz NMR magnet with a full NMR spectral linewidth at half maximum (FWHM) of 2.2 ppm, as determined by an NMR test sample contained in a cylindrical glass tube with a diameter of 5 mm to demonstrate that the shimming method can improve the FWHM to 0.15 ppm. The results demonstrate the strong potential of the proposed RT shimming methodology for the auto-shimming process of NMR/MRI applications.

Laboratory electromagnets are a type of scientific instrumentation widely used to study physical characteristics such as magneto-optical, magnetic hysteresis, and susceptibility properties. In laboratory electromagnets, it is important to generate a high field stably while also reducing the weight. This can generally be achieved by improving the magnetic properties of the ferromagnetic material used for the iron yoke or by increasing the operating current density of the excitation coil. High-temperature superconducting (HTS) coils can generate higher magnetic fields with smaller volumes compared to the copper coils used in conventional laboratory electromagnets due to their high current-carrying capacities. However, when excitation current in conventional HTS coils is generally charged using a power-driven mode, a high heat transfer load from the busbar occurs. The heat transfer load to the HTS coil deteriorates the operational efficiency and stability of the electromagnet system. To mitigate this problem, this paper proposes an inductive link for wireless current charging for laboratory HTS magnets. A magnetic coupler for the inductive link is also designed in consideration of the coupling coefficient, and a resonance circuit and rectifier circuit are designed using elements whose operational characteristics were verified in a cryogenic environment. Evaluating the feasibility of the proposed method is carried out via a finite element analysis combined with an electrical circuit analysis.

Given that REBCO wire is typically manufactured as a tape, it is possible for REBCO magnets to exhibit a relatively larger screening current-induced field (SCF). It is well known that the SCF in an REBCO magnet can be effectively reduced by the so-called current sweep method. However, it requires an overshooting in the magnet current, often close to the magnet's critical current, to effectively suppress the SCF, which may not be favored in terms of operation reliability. In this study, we experimentally validated an alternative approach which mitigates the SCF using thermal cycling together with the current sweep reversal. Well known is the fact that the large load factor, defined as the ratio of operating current to critical current of an REBCO magnet, deteriorates the SCF impact on field uniformity. The key idea is to increase the magnet temperature to increase the effective load factor of the magnet close to its quench limit momentarily, minimize the SCF, and then return back to the nominal operating condition. The combined approach of the thermal cycling and the current sweep may be effective when attempting to eliminate the SCF without ramping an REBCO magnet to a current that may be dangerously high, especially when the magnet is operated at a high operating current. This paper presents the test results of the combined approach in the conduction-cooled REBCO magnet, and the results demonstrate the potential of the approach for more safe and effective elimination of the SCF.

An electron cyclotron is used to heat plasma by driving current in a fusion system. This system requires a strong and accurate magnetic field distribution for the interaction between the electron beam and the radio frequency wave energy [1]. A superconducting magnet is designed for a 170 GHz gyrotron system here. The magnet is composed of conduction cooled NbTi coils, a GM cryocooler with thermal links, supporters, and a cryostat. The magnet was designed using an optimization method that considered the normal stresses generated by electromagnetic forces, the critical current margin, the axial field profile, and field uniformity and losses under AC operation. A quench analysis was also carried out to ensure the safe operation of the gyrotron magnet. The inner bore of the designed superconducting coil is 200 mm to obtain a proper resonance region. A bobbin and structures for thermal insulation were also designed considering the heat transfer and cooling capacities of the cryocooler. The gyrotron magnet will be manufactured using an automatic winding machine based on these design results.

The feasibility of the wireless current charging technique for high-temperature superconductor (HTS) magnets is verified through previous studies. Because the magnitude of the charged current strongly depends on the circuit parameters of the wireless current charging system, this study proposes an optimal design method that increases the efficiency of the system by employing a genetic algorithm. An equivalent circuit model to improve the computing speed is proposed and the overall design process reflecting the equivalent circuit model is introduced. The optimal design for a 3T class target HTS magnet is derived using the proposed method, and a circuit analysis using Simulink is carried out to check the design results. Additional circuit simulations of randomly selected cases for a comparison of the optimal design result are also carried out to verify the performance capabilities of the proposed method.