This study aims to investigate the propagation characteristics of PD currents for future PD localization inside cast resin transformers, by developing a more detailed high-frequency equivalent circuit model of a 6.6 kV instrument cast resin transformer. The frequency characteristics of the impedance between the primary winding terminals of the 6.6 kV transformer were investigated. In addition, the propagation characteristics of transient currents generated by short-circuiting specific interlayer positions in the primary winding using a switch were investigated through both experimental measurements and analytical calculations. The results show reasonable agreement between the measured and calculated impedance frequency characteristics over a wide frequency range up to 10 MHz, validating the proposed high-frequency equivalent circuit model. Furthermore, the relationships among the short-circuit position of the switch, interlayer short-circuit current waveforms, frequency characteristics, and current distribution were clarified. These findings demonstrate that the possibility of estimating PD occurrence positions inside cast resin transformers was suggested by analyzing discharge current waveforms.

ABSTRACTGait disturbance is a common motor symptom in Angelman syndrome (AS), but its characteristics have been poorly studied quantitatively. This study aimed to analyze gait characteristics in school‐age children with AS using three‐dimensional gait analysis (3DGA). Patients with clinically and genetically confirmed AS and healthy children aged 6–15 years were included. For gait assessments, 3DGA was performed using an eight‐camera motion analysis system and eight force plates. Gait metrics, including gait speed, step length, step width, gait variability, gait deviation index, and kinematic and kinetic data of lower extremity joints were compared between the groups. Eight children with AS and 24 healthy controls were evaluated. Seven children with AS had flat feet. While step length and gait speed were similar between groups, children with AS showed greater variability in these parameters and larger step widths. Their average gait deviation index was 74.5, indicating significant gait disturbance, and characteristic features included anterior pelvic tilt, insufficient hip extension, excessive knee flexion during early stance, and reduced ankle joint power. School‐age children with AS exhibit unstable, prancing gait characterized by knee flexion in the early stance phase, quantifiable using 3DGA. These findings provide foundation for evaluating therapeutic interventions.

Droplet-based electricity generators (DEGs) are notable for their simple structure and high instantaneous power output. We evaluated durable and processable polydimethylsiloxane composited with various titania loadings as a tribocharging material for DEGs. The 10 wt% titania loading was found to optimize the tribocharge density of the composite; however, variations in the titania content influenced the surface wettability and droplet resistance. Furthermore, we demonstrated that DEGs could achieve high output power using a multiple dielectric layer structure, which leverages composite films with titania to increase the charge density and minimize droplet resistance.

Resin materials, widely used in insulating applications, are susceptible to partial discharge (PD) erosion. This degradation can result in insulation breakdown. Despite the recognized impact of PD on insulation materials, the detailed effects of varying discharge activity on resin erosion remain underexplored. To investigate the degradation of resin resulting from variations in the discharge activity caused by prolonged charging, an analysis was conducted on the resin surface structure within voids in response to changes in the discharge activity within the simulated voids. The V-Q Lissaj ous method was employed to measure the energy of the discharge inj ected into the voids. As the discharge energy increased with charging time, the discharge activity in the voids weakened, resulting in observable changes in the erosive structure of the resin surface. Prolonged exposure to discharge resulted in localized erosion growth, culminating in the formation of deep pore structures near the columnar structures within the eroded area of the polyethylene terephthalate (PET) owing to PD. The growth of these structures may be attributed to the variations in the crystallinity of the PET on the discharge eroded surface. The evolution of these degradation stages could be ascertained from the change in discharge energy per unit time, and the erosion depth per energy at each stage could be determined. This information can be used for a more accurate prediction of insulation lifetime. In PET, the phenomenon of increased PD resistance at PD eroded area was confirmed. This can lead to the selection and design of more resilient electrical insulation systems. The findings of this study can contribute to improving the reliability and safety of high-voltage equipment.

Droplet-based electricity generators (DEGs) have garnered significant interest due to their straightforward metal substrate/dielectric/metal electrode configurations and their capacity to produce instantaneous high power. This study investigates the influence of droplet conductivity and drop conditions on circuit parameters through an analysis of I-V characteristics under varying load resistance conditions. The results reveal that alterations in droplet resistance and polytetrafluoroethylene (PTFE) charge density due to varying droplet dynamics play a pivotal role in shaping DEG output. The charged state of PTFE on DEG was found to differ with the expansion and contraction of the droplets.

To investigate the degree of partial discharge degradation of resins and resin composites due to long-term application of voltage, attempts have been made to determine changes in discharge activity based on $\Phi-\mathrm{q}-\mathrm{n}$ characteristics. However, it was not possible to accurately determine the actual discharge activity occurring within the defects from the measurement of the discharge amount alone. Therefore, an attempt was made to analyze the changes in discharge activity by visualizing the discharge emission inside defects and correlating the actual discharge state with changes in the $\Phi-\mathrm{q}-\mathrm{n}$ distribution. In this study, a spherical electrode/polyethylene terephthalate (PET)/cylindrical void/PET/flat plate electrode system was employed as the artificial defect structure, and an indium tin oxide (ITO) transparent electrode was used as the flat plate electrode to enable direct observation of the light emission during partial discharge generation. This enabled the analysis of changes in the $\Phi-\mathrm{q}-\mathrm{n}$ distribution and discharge state for investigating the changes in discharge activity. In this study, the changes in the discharge activity during long-term voltage application in a sealed void structure were investigated. The results demonstrated that even under the same void structure and test voltage conditions, protrusions may be generated because of discharge byproducts, and that the discharge occurring in these protrusive structures significantly affected the discharge activity and erosion morphology.

This paper presents a high-frequency equivalent circuit model applicable for partial discharge (PD) location in an inductive test of a 6.6 kV-VT cast resin transformer (CRTr), in which a voltage is applied between the high-voltage terminals. Proposed equivalent circuit consists of the winding inductance, and the capacitance between adjacent inter-windings and that between the winding and ground of CRTr. The proposed circuit allows to simulate PD phenomena occurring in the windings. The estimation of the dominant frequency f r for PD detection can be achieved through the frequency characteristics of the impedance Z(f) measurement of CRTr and the calculation of its high-frequency equivalent circuit. This allows for the identification of PD and noise in the field, leading to improved defect detection sensitivity. Measurements of PD current waveforms were also made in a 6.6 kV VT with the inductive test circuit. Measured results were compared with waveforms calculated using the equivalent circuit. As a result, it was found that the polarity of the rising part of the current and dominant frequency components of simulated PD current waveforms were almost consistent with experimental ones.

Water-droplet-based electricity generators (DEGs) have attracted considerable attention owing to their simple metal substrate/dielectric/metal electrode structure and ability to generate high power instantaneously. However, their characteristics are significantly affected by the behavior of water droplets. In this study, to verify the relationship between water droplet movement and DEG output characteristics, we fabricated DEGs with two different structures. The electrodes were arranged vertically and horizontally with respect to the sliding direction of the water droplet, and DEG operation with different water droplet positions was verified. The results indicated that DEG output voltage varied according to water droplet behavior. Moreover, when the water droplet came in contact with an electrode, the wetting effect modified the shape of the droplet, thereby changing DEG output characteristics.

Recently water droplet-based electricity generators (DEGs), which utilize triboelectricity between a droplet and a dielectric material, has a great attention. DEG generates an instantaneous high-power density despite its simple metal/dielectric/metal stack structure. In the DEG, the contact area between a droplet and a dielectric surface affects the output characteristics. We fabricated a DEG using a PTFE film as a dielectric material, measured the output voltage and evaluated the contact area in various dropping heights and positions. We demonstrated that the output peak voltage increased as the contact area increased related to spreading and rebounding of a droplet.

To investigate the degree of partial discharge degradation of resins and resin composites due to long-term application of voltage, attempts have been made to determine changes in discharge activity based on <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Phi-\mathrm{q}-\mathrm{n}$</tex> characteristics. However, it was not possible to accurately determine the actual discharge activity occurring within the defects from the measurement of the discharge amount alone. Therefore, an attempt was made to analyze the changes in discharge activity by visualizing the discharge emission inside defects and correlating the actual discharge state with changes in the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Phi-\mathrm{q}-\mathrm{n}$</tex> distribution. In this study, a spherical electrode/polyethylene terephthalate (PET)/cylindrical void/PET/flat plate electrode system was employed as the artificial defect structure, and an indium tin oxide (ITO) transparent electrode was used as the flat plate electrode to enable direct observation of the light emission during partial discharge generation. This enabled the analysis of changes in the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Phi-\mathrm{q}-\mathrm{n}$</tex> distribution and discharge state for investigating the changes in discharge activity. In this study, the changes in the discharge activity during long-term voltage application in a sealed void structure were investigated. The results demonstrated that even under the same void structure and test voltage conditions, protrusions may be generated because of discharge byproducts, and that the discharge occurring in these protrusive structures significantly affected the discharge activity and erosion morphology.

We have proposed a method for determining the dominant frequency of a mold resin transformer (CRTr) by deriving a high-frequency equivalent circuit from impedance frequency characteristics measurements and calculating the partial discharge (PD) detection waveform. In this paper, a new high frequency equivalent circuit model is proposed based on the frequency characteristics of the impedance in 6. 6kV voltage transformer (VT), taking into account the internal winding structure. It was shown that the dominant frequency of the PD current analyzed using the equivalent circuit generally agreed with the actual measurement. In addition, an inductive test was conducted for the 6. 6kV-VT by applying voltage to the high voltage terminals. An attempt was made to identify the dominant frequency components of the PD current detected by high frequency CTs installed in the ground wire.

This study aims to establish an insulation diagnosis technique using partial discharge (PD) detection for cast resin transformers (CRTr). In the previous paper, the frequency components of PD current in a PD test of a CRTr by applying AC voltage between lumped high voltage and low voltage terminals were identified and analyzed in EMTP using an equivalent circuit model. On the other hand, another PD test is the test with an inductive voltage application in which an AC voltage is applied to the low voltage side of the transformer and then a high voltage is applied between the high voltage terminals in a transformer. This paper presents investigation on dominant frequency of PD current detected with high frequency current transformer (CT) in the inductive PD test of a 6.6 kV cast resin voltage transformer 6.6 kV CRTr-VT. An attempt is also made to identify PD signal source, the signal propagation path of the PD current, as well as the dominant frequency components.

Changes in the q-Φ-n distribution of partial discharge (PD) generated by a simulated defect structure have conventionally been investigated to determine the degree of partial discharge degradation of resin or resin composite materials due to long-term application of voltage. The purpose of this study is to analyze the relationship between the change in the q-Φ-n distribution and of that in the discharge state occurring inside the defect. A spherical electrode/ polyethyleneterephthalate (PET)/ cylindrical void/ PET/flat plate electrode system was employed as an artificial defect structure, and an Indium tin oxide (ITO) transparent electrode was used as a flat plate electrode to enable direct observation of the light emissions during the occurrence of partial discharge. The observations of changes in the q-Φ-n distribution and the discharge state occurring inside the defects are presented in this paper. Furthermore, the mechanism of resin degradation is discussed based on the observation results of resin surfaces exposed to partial discharge for a long term. We found that the degradation of PET surface progressed faster when the PD was sustained at the protruding structure, which is a PD byproduct.

We describe two patients with NSD1 deletion, who presented with early-onset, or recurrent cerebrovascular diseases (CVDs). A 39-year-old female showed developmental delay and abnormal gait in infancy, and developed slowly-progressive intellectual disability and movement disorders. Brain imaging suggested recurrent parenchymal hemorrhages. A 6-year-old male had tremor as a neonate and brain imaging revealed subdural hematoma and brain contusion. This report suggests possible involvement of CVDs associated with NSD1 deletion.

Superhydrophobic surfaces can be obtained by fabricating hierarchical rough structures with low surface energies. In this study, composites with such superhydrophobic surfaces were fabricated by spin-coating a suspension composed of polydimethylsiloxane, ethanol, hexane, and silica powder. The composite exhibits a three-layered hierarchical structure comprising protrusions and pores resulting from liquid-liquid phase separation and silica aggregation. The fabricated three-layered hierarchical-structured composite films demonstrate water contact angles greater than 155 degrees and sliding angles less than 10 degrees. The results indicate that the proposed process is simple and useful in fabricating superhydrophobic surfaces.

Introduction: SCN8A-related epilepsy has various phenotypes. In particular, patients with developmental and epileptic encephalopathy (DEE) are resistant to antiepileptic drugs and may present with autonomic symptoms, such as marked bradycardia and apnea during seizures, and thus have an increased risk of sudden death. Herein, we report a case of very severe SCN8A-related epilepsy necessitating cardiac pacemaker implantation because of repetitive ictal asystole. Case report: The patient was a 14-month-old girl. Tremor and generalized tonic seizure occurred after birth. During seizures, bradycardia and perioral cyanosis occurred, and then, after developing tachycardia and apnea, marked bradycardia and generalized cyanosis occurred, which sometimes resulted in ictal asystole requiring cardiopulmonary resuscitation. Her seizures were refractory to antiepileptic drugs. As the seizures requiring resuscitation did not decrease, cardiac pacemaker implantation was performed four months after birth. Exome sequencing revealed a heterozygous de novo variant in SCN8A (NM_014191.3:c.4934T>C,p.(Met1645 Thr)). Even though phenytoin was effective, seizures with bradycardia remained approximately once a month, and pacemaker activity was observed. Conclusions: This is, to our knowledge, the first reported case of SCN8A-related DEE in whom pacemaker implantation was performed. Pacemaker implantation should be considered as a treatment option for critical patients with SCN8A-related DEE as in the present case, because the incidence of sudden unexpected death in epilepsy is reported to be approximately 10% in patients with SCN8A-related DEE. (c) 2021 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

Superhydrophobic surfaces have important applications in daily lives as well in various industries. In this study, composites with superhydrophobic surfaces were fabricated from polydimethylsiloxane-based hybrid materials and ceramic nanopowders by electrophoretic deposition. Under different appropriate conditions, such as the amount of a particular component, the composite possessed a three-layered hierarchical surface. The fabricated composite films comprising three-layered hierarchical structures exhibited contact angles greater than 160 degrees and contact angle hystereses as well as sliding angles less than 5 degrees.

Pelizaeus-Merzbacher disease (PMD) is an X-linked recessive disorder caused by abnormalities in the gene PLP1. Most females harboring heterozygous PLP1 abnormalities are basically asymptomatic. However, as a result of abnormal patterns of X-chromosome inactivation, it is possible for some female carriers to be symptomatic. Whole-exome sequencing of a female patient with unknown spastic paraplegia was performed to obtain a molecular diagnosis. As a result, a de novo heterozygous single-nucleotide deletion in PLP1 [NM_000533.5(PLP1_v001):c.783del; p.Thr262Leufs*20] was identified. RNA sequencing was performed in a patient-derived lymphoblastoid cell line, confirming mono-allelic expression of the mutated allele and abnormal inactivation of the wild-type allele. The patient-derived lymphoblastoid cell line was then treated with VX680 or 5azadC, which resulted in restored expression of the wild-type allele. These two agents thus have the potential to reverse inappropriately-skewed inactivation of the X-chromosome.