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This paper studies the relationship between the magnetizing inductances of a transformer and of a choke coil in high-voltage power supplies. This analysis defines the conditions for high switching frequency and stable operation of high-voltage power supplies without the power loss increase. This approach is confirmed by the implementation of a high-voltage power supply operating at 200 kHz with a high efficiency of 86%.

an effective means to achieve a small and light-weight high-voltage power supply is to raise the conversion frequency of the supply. At present, however, the conversion frequency is largely limited by the distributed capacitance of high-voltage transformers and the switching time to semiconductor devices. Reduction of the distributed capacitance of a high-voltage transformer and a new method of analysis which can quantitatively describe the relation between transformer structure and distributed capacitance were achieved. Using the proposed method of analysis, the distributed capacitance is calculated using the winding scheme, core dimension, number of bobbin splits, class and material for winding insulation, core size and impregnation material as the parameters. The calculated values are compared with the measured values and the effects of the parameters on the distributed capacitance are discussed. By using a four-split bobbin. The capacitance using the core with a circular center pole is reduced by approximately 10 percent compared with the square center pole. Using class 1 insulation winding, the capacitance is reduced by 10 percent compared with class 2 winding insulation material. [ABSTRACT FROM AUTHOR]

Background: It has been reported that it is sometimes difficult to make a diagnosis of gastric cancer detected after Helicobacter pylori (H. pylori ) eradication. Therefore, we conducted a study to determine the usefulness of magnifying endoscopy using vessel plus surface classification system for making a diagnosis of early gastric cancer after H. pylori eradication., Method: Usefulness of the markers of the vessel plus surface classification system for diagnosing gastric cancer using magnifying endoscopy with narrow-band imaging was investigated for gastric cancer detected after H. pylori eradication ( H. pylori -eradicated group) vs. H. pylori -positive gastric cancer ( H. pylori -positive group)., Results: 85 lesions were included in this study. The H. pylori -eradicated group comprised 27 lesions, whereas the H. pylori -positive group comprised 58 lesions. As for magnified endoscopic findings based on the vessel plus surface classification system, the respective positivity rates in the H. pylori -eradicated group vs. those in the H. pylori -positive group were as follows: demarcation line, 100% (27/27) vs. 100% (58/58); irregular microvascular pattern, 100% (27/27) vs. 100% (58/58); and irregular microsurface pattern, 78% (21/27) vs. 95% (55/58). There was no significant difference in the positivity rates of the demarcation line and irregular microvascular pattern between the groups. The positivity rate of the irregular microsurface pattern was significantly lower in the H. pylori -eradicated group than in the H. pylori -positive group (P = 0.03)., Conclusion: We presume that the microvascular pattern is more useful than the microsurface pattern as a diagnostic marker in cases of gastric cancer detected after H. pylori eradication., Competing Interests: Conflict of Interest: None, (Copyright: © 2021 Hellenic Society of Gastroenterology.)

A 75-year-old woman with amyotrophic lateral sclerosis (ALS) underwent surgical gastrostomy and repair of incisional hernia. Anesthesia was induced with propofol and high concentrations of sevoflurane. Tracheal intubation was performed without muscle relaxants. Anesthesia was maintained with sevoflurane and thoracic epidural anesthesia (bupivacaine and fentanyl). Surgery, emergence and extubation were completed uneventfully. She was transferred to ICU for postoperative observation. On the 2 nd POD, however, she was re-intubated due to sudden dyspnea and desaturation caused by failed sputum exhaustion. Simultaneously, her ECG showed ischemic change in leads I, III, aVF, and V3-6. Left ventriculogram showed an "Ampulla" or so called "Takotsubo" shape with intact coronary angiogram. After medication with nitroglycerin and diltiazem, her ECG returned to normal. She showed no deterioration of neurological symptoms. No respiratory and cardiac events were reported until her discharge from hospital. We conclude that an extreme care is required in patient with ALS to avoid perioperative complications.