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In electric railway systems, wear of current collector devices leads to high maintenance cost. To develop a cost reduction methodology, the wear behavior of current collector materials needs to be fully investigated. However, the wear test apparatuses currently in use cannot control the contact force between materials, and the contact force fluctuates. It is difficult to classify accurate conditions of a wear transition under contact force fluctuation. To solve this problem, we propose a force control system with acceleration and velocity feedbacks to suppress the force fluctuation. The positive feedback of acceleration compensates the periodic force fluctuation at frequencies according to the sliding velocity of rubbing surfaces. The velocity feedback compensates the force fluctuation caused by resonance. The proposed control system is validated by experiments using a prototype of a rotary wear test apparatus.

Significance The mechanisms of α-synuclein aggregation and subsequent Lewy body formation are a key pathogenesis of Parkinson’s disease (PD). PARK14-linked PD, which is caused by mutations of the iPLA2-VIA/PLA2G6 gene, exhibits a marked Lewy body pathology. iPLA2-VIA, which belongs to the phospholipase A2 family, is another causative gene of neurodegeneration with brain iron accumulation (NBIA). Here, we demonstrate that iPLA2-VIA loss results in acyl-chain shortening in phospholipids, which affects ER homeostasis and neurotransmission and promotes α-synuclein aggregation. The administration of linoleic acid or the overexpression of C19orf12, one of the NBIA-causative genes, also suppresses the acyl-chain shortening by iPLA2-VIA loss. The rescue of iPLA2-VIA phenotypes by C19orf12 provides significant molecular insight into the underlying common pathogenesis of PD and NBIA., Mutations in the iPLA2-VIA/PLA2G6 gene are responsible for PARK14-linked Parkinson’s disease (PD) with α-synucleinopathy. However, it is unclear how iPLA2-VIA mutations lead to α-synuclein (α-Syn) aggregation and dopaminergic (DA) neurodegeneration. Here, we report that iPLA2-VIA–deficient Drosophila exhibits defects in neurotransmission during early developmental stages and progressive cell loss throughout the brain, including degeneration of the DA neurons. Lipid analysis of brain tissues reveals that the acyl-chain length of phospholipids is shortened by iPLA2-VIA loss, which causes endoplasmic reticulum (ER) stress through membrane lipid disequilibrium. The introduction of wild-type human iPLA2-VIA or the mitochondria–ER contact site-resident protein C19orf12 in iPLA2-VIA–deficient flies rescues the phenotypes associated with altered lipid composition, ER stress, and DA neurodegeneration, whereas the introduction of a disease-associated missense mutant, iPLA2-VIA A80T, fails to suppress these phenotypes. The acceleration of α-Syn aggregation by iPLA2-VIA loss is suppressed by the administration of linoleic acid, correcting the brain lipid composition. Our findings suggest that membrane remodeling by iPLA2-VIA is required for the survival of DA neurons and α-Syn stability.

Conventionally, several reports on quantification of wear of current collecting materials have been published. The objectives of these reports were to predict the wear of current collecting materials in field. However, the measure to reduce the wear of current collecting materials has not been proposed yet. In this paper, the authors focus on wear mode transition phenomena to propose the wear reduction measure, and carry out an electric potential distribution analysis and a temperature distribution analysis. From the analysis results, it is found that the relationship between electric potential and temperature is formed parabolic curve, and the curve depends on only a contact voltage. Further, the authors propose a “wear mode map” which shows transition conditions between the wear modes under electric flowing condition by formulating the parabolic curve. According to the wear mode map, the authors identify the three dominant parameters of wear mode transition as a contact voltage, contact resistances include film resistance and melting points of current collecting materials.

To clarify the wear mechanism of current collecting materials such as a contact wire and a contact strip under electric current condition, it is necessary to clarify temperature distribution around the contact spot. However, the traditional method of estimating the maximum contact temperature such as the φ-θ theory cannot estimate the temperature distribution. In this paper, we newly proposed an electric field analysis model of hard-drawn copper and iron-based sintered alloy considering a degenerated layer such as an oxide film and wear debris. Then, we newly proposed the heat conduction equation applying the Wiedemann-Franz law, and analyzed temperature distribution in electrodes. As a result, we find that the relation between the maximum temperature and the contact voltage even in dissimilar electrodes are based on the φ-θ theory. The temperature distribution in electrode changes depending on whether or not degenerated layers exist, and the maximum temperatures of each electrode are not necessarily the same as those estimated by the φ-θ theory. Finally, we clarify the influence of the degenerated layer on the melting condition of electrodes, and explain the electric wear phenomena observed in the previous wear test.

Introduction. There have been few reports on the ictal video electroencephalogram (VEEG) of amnesic attacks in patients with transient epileptic amnesia (TEA). TEA attacks often occur on waking, but the reason remains unclear. Results. A 65-year-old man had a three-month history of recurrent episodes of antero- and retrograde amnesia. The episodes lasted for 10–20 minutes and occurred 2-3 times per month. Brief episodes of behavioral arrest were also witnessed. TEA was suspected, but routine EEG was equivocal. Therefore, we performed a long-term VEEG monitoring. On the second night of the monitoring, a focal onset seizure with subtle motor manifestation occurred during N2 sleep. Following sudden onset tachycardia, EEG seizure patterns arose from the right temporal regions, spread to the left, and terminated in about 90 seconds. About 20 seconds after the seizure cessation, he awoke while EEG was almost normal. On awakening, he showed transient amnesia lasting around 30 minutes, which was confirmed by bystanders. Both antero- and retrograde amnesia were observed. The diagnosis of TEA was made. Lacosamide 50 mg twice daily resolved seizures. Conclusion. We provide the first evidence that TEA attacks on waking reflect postictal hippocampal dysfunction due to unrecognized seizures during sleep. This finding is in line with that the duration of TEA episodes is longer than typical temporal lobe seizures.

A recessive mutation in PLA2G6, which is known to cause infantile neuroaxonal dystrophy (INAD) and neurodegeneration associated with brain iron accumulation (NBIA), has recently been shown to be responsible for PARK14-linked dystonia-parkinsonism. To study the frequency of PLA2G6 mutations, including those caused by gene rearrangement in patients with parkinsonism, we performed direct sequencing and investigated copy number variations (CNVs) of this gene in 109 Japanese patients with parkinsonism. Direct sequencing revealed a homozygous mutation (c.1495G>A; p.A499T), which is likely to be pathogenic and is already registered as rs141045127, and two compound-heterozygous mutations we have previously reported. No CNVs in PLA2G6 were detected in our subjects. Our results suggest that CNV in PLA2G6 is rare in parkinsonism, at least in the Japanese population, in contrast to the reports of its frequency in INAD. Further large studies in various populations are warranted to elucidate what causes the difference in frequencies of PLA2G6 rearrangement mutations between INAD and dystonia-parkinsonism.

Central pontine myelinolysis (CPM), which was originally considered to be the result of rapid correction of chronic hyponatremia, is not necessarily accompanied by hyponatremia or drastic changes in serum sodium level. Here, we report a case of an anorexic 55-year-old male with a history of pharyngo-laryngo-esophagogastrectomy, initially hospitalized with status epilepticus. Although his consciousness gradually recovered as we were controlling his convulsion, it deteriorated again with new onset of anisocoria, and magnetic resonance imaging (MRI) at this point revealed CPM. Rapid change of serum sodium or osmolarity, which is often associated with CPM, had not been apparent throughout his hospitalization. Instead, a review of the serum biochemistry test results showed that serum phosphate had drastically declined the day before the MRI first detected CPM. In this case, we suspect that hypophosphatemia induced by refeeding syndrome greatly contributed to the occurrence of CPM.

To suggest measures for reducing wear of current collecting materials such as contact wires and contact strips, it is necessary to understand actual phenomena generated at the point of electric contact. For this study on classification of wear modes and transition conditions between hard drawn copper contact wire and iron-based sintered alloy contact strips, a linear wear testing method was newly introduced. As a result, it was found that the contact temperature which was estimated from the contact voltage depended on electric current and contact load. Consequently it was possible to classify wear modes of the current collecting materials under electric current conditions into three types depending on the maximum contact temperature.

We report a case of a 22-year-old male who was transferred to our hospital in a comatose state following successive seizures. Low blood glucose had been detected upon his arrival at the previous hospital. He became responsive 12 days after the onset of coma. Upon regaining consciousness he exhibited severe dysarthria and several interhemispheric disconnection signs such as intermanual conflict, left-hand dysgraphia, left hemispatial neglect confined to the right hand, impaired interhemispheric transfer, and unilateral constructional apraxia of the right hand. Brain MRI disclosed T2-weighted and diffusion-weighted hyperintense lesions with reduced apparent diffusion coefficients in the bilateral centrum semiovale, splenium of the corpus callosum, right posterior limb of the internal capsule, and bilateral middle cerebellar peduncles. As the MRI findings vanished, his interhemispheric disconnection signs gradually resolved. Abdominal imaging studies revealed a pancreatic tumor, which was later endocrinologically diagnosed as an insulinoma. This is an extremely rare report of interhemispheric disconnection signs due to hypoglycemic encephalopathy. The lesions in the bilateral centrum semiovale likely contributed to the interhemispheric disconnection signs.

The wear behavior of copper-impregnated carbon fiber reinforced carbon composites (C/C composites) was investigated using a block-on-ring type wear tester during application of a DC electrical current. Three types of C/C composite contact strip materials were tested. The wear test was carried out at a constant sliding speed of 55.6 m/s with a normal load of 59 N, and applied electrical currents ranging from 100 to 500 A. The arc-discharging rate, which is defined as the ratio of arc-discharging time to total sliding time, ranged from 0% to 35%. We also investigated the thermal and oxidation properties of the C/C composites with the laser flash method and TG-DTA. The results of the wear experiments indicate that the wear of copper-impregnated C/C composite contact strips was proportional to the arc discharge energy, which can be calculated from measurements of contact voltage and electrical current. The C/C composite contact strips with high strength carbon fiber were more likely to wear under high arc discharge energy conditions. The C/C composites made of higher strength carbon fiber have lower thermal conductivities and were more likely to be pyrolyzed or degraded by oxidation than the C/C composite with lower strength carbon fiber. These differences are thought to contribute to the difference in the wear behavior.

For this study, the authors designed a cross-section shape of contact wire in order to reduce the bending strain that is exerted on contact wire with every pantograph passage. This bending strain can result in fatigue fracture of the contact wire. The authors confirmed that the newly-designed cross-section shape did not worsen galloping property and could be applied to manufacturing contact wire with high strength copper alloy. In addition, no compatibility problems with fittings were found, and meaningful decreases in bending strain were observed in pantograph running tests.

In wear tests under high speed conditions for the contact current collection system of electric trains, a load given to materials fluctuates largely. This fluctuation disturbs the accurate measurement of the wear mode transition. Force control is one of the solutions against the problem of controlling a load. Force control systems using reaction force observer often assume that motors contact with the stationary environment. However, the environmental position varies during a wear test. Therefore, the disturbance force due to this variation has to be considered in the reaction force observer. This paper shows that the environmental acceleration can be regarded as the disturbance force. Experimental results show the validity of the compensation in the reaction force observer using a miniature model of the rotary wear test apparatus.

Mutations in CHCHD2 have been identified in some Parkinson's disease (PD) cases. To understand the physiological and pathological roles of CHCHD2, we manipulated the expression of CHCHD2 in Drosophila and mammalian cells. The loss of CHCHD2 in Drosophila causes abnormal matrix structures and impaired oxygen respiration in mitochondria, leading to oxidative stress, dopaminergic neuron loss and motor dysfunction with age. These PD-associated phenotypes are rescued by the overexpression of the translation inhibitor 4E-BP and by the introduction of human CHCHD2 but not its PD-associated mutants. CHCHD2 is upregulated by various mitochondrial stresses, including the destabilization of mitochondrial genomes and unfolded protein stress, in Drosophila. CHCHD2 binds to cytochrome c along with a member of the Bax inhibitor-1 superfamily, MICS1, and modulated cell death signalling, suggesting that CHCHD2 dynamically regulates the functions of cytochrome c in both oxidative phosphorylation and cell death in response to mitochondrial stress., Mutations in CHCHD2 are associated with Parkinson's disease. Here the authors investigate the physiological and pathological roles of CHCHD2 in Drosophila and mammalian cells, and find that it regulates mitochondrial respiration through stabilizing cytochrome c.

Vacuolar protein sorting 35 (VPS35) was recently reported to be a pathogenic gene for late- onset autosomal dominant Parkinson's disease (PD), using exome sequencing. To date, VPS35 mutations have been detected only in whites with PD. The aim of the present study was to determine the incidence and clinical features of Asian PD patients with VPS35 muta- tions. We screened 7 reported nonsynonymous mis- sense variants of VPS35, including p.D620N, known as potentially disease-associated variants of PD, in 300 Japanese index patients with autosomal dominant PD and 433 patients with sporadic PD (SPD) by direct sequencing or high-resolution melting (HRM) analysis. In addition, we screened 579 controls for the p.D620N mutation by HRM analysis. The p.D620N mutation was detected in 3 patients with autosomal dominant PD (1.0%), in 1 patient with SPD (0.23%), and in no con- trols. None of the other reported variants of VPS35 were detected. Haplotype analysis suggested at least 3 independent founders for Japanese patients with p.D620N mutation. Patients with the VPS35 mutation showed typical tremor-predominant PD. We report Asian PD patients with the VPS35 mutation. Although VPS35 mutations are uncommon in PD, the frequency of such mutation is relatively higher in Japanese than reported in other populations. In VPS35, p.D620N sub- stitution may be a mutational hot spot across different ethnic populations. Based on the clinical features, VPS35 should be analyzed in patients with PD, espe- cially autosomal dominant PD or tremor-predominant PD. V C 2012 Movement Disorder Society

We report a case of a small cortical infarction in the postcentral gyrus that presented an isolated hemicape-like sensory disturbance. A 47-year-old man suddenly developed numbness and paresthesia in the left neck, shoulder, arm, and upper trunk. Examination revealed hypoesthesia to touch and pain in these areas along with a hemicape-like distribution. The sensitivity to cold and vibration was normal, and two-point discrimination and graphesthesia were preserved. The patient had a normal visual field, muscle strength, and reflexes, and there were no neuropsychological deficits. Magnetic resonance imaging (MRI) demonstrated a fresh, small cerebral infarction in the right postcentral gyrus, which was superior medial to the precentral knob. The area of infarction in this patient corresponds well with the area of the upper trunk, neck, head, shoulder, and arm in the sensory homunculus drawn by Penfield and Rassumussen. The spinal MRI was normal. Transesophageal echocardiography disclosed a patent foramen ovale with a right-to-left-shunt. The patient was diagnosed as having acute cerebral infarction, probably due to paradoxical embolism, and was treated with warfarin. A small localized infarct in the postcentral gyrus can present an isolated sensory disturbance with an atypical hemicape-like distribution.

The rain flow method has been put forward as a method for waveform counting to estimate what the fatigue life span would be under actual waveform stress. The authors carried out experiments to test its applicability to hard drawn copper contact wire. In order to consider the effect of mean tensile stress when applying the rain flow method it is first necessary to define the fatigue life span properties for the various mean tensile stresses. The authors confirmed that these estimations can be found using fatigue test results from hard drawn copper contact wire placed under two types of mean tensile stress condition. The authors then conducted six fatigue tests to investigate the applicability of the rain flow method. The actual measured fatigue life span in tests generally exceeded estimations. The rain flow method may therefore conceivably be used to derive a method for safe estimation of fatigue life.

When a pantograph passes underneath a contact wire, the upward force causes a bending stress in the contact wire. If this stress is high and occurs frequently, there is a possibility that the contact wire will suffer a fatigue fracture. To estimate the fatigue life of a contact wire, we have been using the S-N curve prepared for a mean stress of 88.2 MPa. In addition, a contact wire is gradually worn down by running contact strips so that the mean stress governing its fatigue life gradually increases. To estimate the fatigue life of a worn contact wire correctly, therefore, the influence of the mean stress on contact wire fatigue needs to be examined. For this paper, we carried out fatigue tests on GT110 harddrawn copper contact wire at a mean stress of 154.2 MPa to obtain another S-N curve. Then, by using parameters that included the mean stress, we prepared a fatigue curve that integrates S-N curves for any mean stress. Finally, we estimated contact wire fatigue damage using this fatigue curve and proposed a new method to establish the allowable bending strain amplitude.

PLA2G6 was reported recently as the causative gene for PARK14-linked autosomal recessive early-onset dystonia-parkinsonism. In a recent study in Singapore, heterozygous PLA2G6 p.P806R (c.2417CG) mutation in exon 17 was reported to be a possible Parkinson's disease (PD)-related mutation. To determine the significance of the PLA2G6 mutation, we conducted an association study by performing direct sequencing of PLA2G6 exon 17 in 379 Japanese sporadic PD patients and 310 controls in the Japanese general population. In this group, we found 12 patients (12/379=3.16%) and 10 controls (10/310=3.23%) with a heterozygous p.P806R mutation (P=0.96, χ(2)=0.0019). Therefore, our large case-controlled study suggests that PLA2G6 p.P806R is not a disease-associated polymorphism in PD. Moreover, we performed direct sequencing of all exons and exon-intron boundaries of PLA2G6 in 116 Japanese patients with sporadic PD. Two single heterozygous variants (p.R301C or p.D331N) were found (both frequencies: 1/379 patients vs 0/310 controls) and the roles of their variants were unclear. Finally, combined with the previous report, our findings emphasize that PLA2G6 mutations are unlikely to be the major causes or risk factors of PD at least in Asian populations. However, further large studies in various populations are needed because patients with PLA2G6 mutations can show heterogeneous clinical features.

We evaluated the contributions of various polyglutamine (polyQ) disease genes to Parkinson's disease (PD). We compared the distributions of polyQ repeat lengths in 8 common genes (ATXN1, ATXN2, ATXN3, CACNA1A, ATXN7, TBP, ATN1, and HTT) in 299 unrelated patients with autosomal dominant PD (ADPD) and 329 normal controls. We also analyzed the possibility of genetic interactions between ATXN1 and ATXN2, ATXN2 and ATXN3, and ATXN2 and CACNA1A. Intermediate-length polyQ expansions (24 Qs) of ATXN2 were found in 7 ADPD patients and no controls (7/299 = 2.34% and 0/329 = 0%, respectively; p = 0.00530.05/8 after Bonferroni correction). These patients showed typical L-DOPA-responsive PD phenotypes. Conversely, no significant differences in polyQ repeat lengths were found between the ADPD patients and the controls for the other 7 genes. Our results may support the hypothesis that ATXN2 polyQ expansion is a specific predisposing factor for multiple neurodegenerative diseases.