Stability and safety estimates and tests of a superconducting bus-line for large-scale superconducting coils

We have been developing a flexible superconducting bus-line as a unit electrical feeder between large-scale superconducting coils and their power supplies away from the coils. The designed superconducting bus-line consists of a pair of +/- aluminum stabilized NbTi/Cu compacted strand cables and a coaxial four-channel transfer line. A full-scale model of the SC bus-line (20 m long) has been constructed and tested successfully up to 40 kA without a quench under the short-circuit condition. Stability tests were also done by inducing a forced quench with heaters. A minimum propagation current larger than 32.5 kA was confirmed. Thus, the bus-line was cryogenically stabilized at the rated current of 30 kA. We have examined the test results and evaluated the stability and safety margins of this bus-line. The design criteria for a superconducting bus-line are also shown for large-scale superconducting coils with operating current as a parameter

Development and tests of a flexible superconducting bus-line for the Large Helical Device

A flexible superconducting bus-line is proposed as an electrical feeder between the superconducting coils of the Large Helical Device (LHD) and the device\u27s power supplies. The bus-line consists of superconducting cables and a cryogenic flexible transfer-line. A specially developed aluminum stabilized NbTi/Cu compacted strand cable satisfies requirements for large current capacity, high stability, high reliability and flexibility. A full-scale model with a length of 20 m was designed and constructed to investigate the feasibility and performance of the superconducting bus-line. Its fabrication, transportation, installation, cooling and excitation tests were successfully carried out. The bus-line was very stable and could be excited up to 40 kA (rated current is 30 kA) without a quench. The stability, current distribution and heat load were also measure

Nationwide survey of Lambert-Eaton myasthenic syndrome in Japan

Background There was no nationwide epidemiological study of Lambert-Eaton myasthenic syndrome (LEMS) in Japan; therefore, we conducted a nationwide survey.Methods For the first survey, we sent survey sheets to randomly selected medical departments (n=7545) to obtain the number of LEMS who visited medical departments between 1 January 2017 and 31 December 2017. For the second survey, we sent survey sheets to the corresponding medical departments to obtain clinical information on LEMS.Results We received 2708 responses (recovery rate: 35.9%) to the first survey. We estimated the number of LEMS as 348 (95% CI 247 to 449). The prevalence was 2.7 (95% CI 1.9 to 3.5) in 1 000 000 population. As a result of the second survey, we obtained 30 case records of 16 men and 14 women. Fourteen patients (46.7%) had a tumour, and 10 out of 14 tumours were small-cell lung carcinoma (71.4%). There was a predominance of men in the LEMS with tumour (paraneoplastic LEMS, P-LEMS) (n=11, 78.6%) and women in the LEMS without tumour (a primary autoimmune form of LEMS, AI-LEMS) (n=11, 68.8%) (p=0.0136). The onset age (mean (SD)) for the P-LEMS was 67.1 (9.0), and that for AI-LEMS was 57.8 (11.2) years old (p=0.0103). The disease duration (median) for P-LEMS was 2 years, and for AI-LEMS was 7.5 years (p=0.0134).Conclusions The prevalence of LEMS in Japan is similar to that in other countries. There are predominances of men in P-LEMS and women in AI-LEMS

The Association of H. pylori Infection and Patterns of Erythematous Gastric Mucosa

It has been uncertain what types of erythematous gastric mucosa are produced by Helicobacter pylori (H. pylori)-infection. We therefore design the present study to identify the type of erythematous mucosa associated with H. pylori-infection. A total of 590 consecutive Japanese patients (mean age 58.7 years, 185 men and 405 women) referred to our hospital for diagnostic upper gastrointestinal endoscopy were recruited in this study. We assessed endoscopically the type of gastric mucosal erythema, including spotty erythema, haemorrhagic erosion, reddish streaks, and raised erosion. H. pylori infection was diagnosed by a positive endoscopic 13C-urea breath test (e-UBT). Of the 402 H. pylori-positive subjects, spotty erythemas in the corpus were found in 177 (44.0%), haemorrhagic erosions in 26 (6.5%), reddish streaks in the antrum in 21 (5.2%) and in the corpus in 10 (2.5%), and raised erosions in the antrum in 58 (14.4%) and in the corpus in 4 (1.0%). For spotty erythema in the upper body, sensitivity was 44.0%, specificity was 92.6% for H. pylori infection. Seventy-two (86.7%) of 83 patients with antral reddish streaks and 65 (52.8%) of 123 patients with antral raised erosions had H. pylori-negative e-UBT. Spotty erythema in the corpus was one of most frequent endoscopic findings reflecting H. pylori infection. In contrast, antral reddish streaks and raised erosions were likely to indicate the absence of H. pylori