• Title/Summary/Keyword: Polarization and depolarization current

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Study on Influences and Elimination of Test Temperature on PDC Characteristic Spectroscopy of Oil-Paper Insulation System

  • Liu, Xiao;Liao, Ruijin;Lv, Yandong;Liu, Jiefeng;Gao, Jun;Hao, Jian
    • Journal of Electrical Engineering and Technology
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    • v.10 no.3
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    • pp.1107-1113
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    • 2015
  • Test temperature is an important factor affecting the measurement results of dielectric response of field power transformers. In order to better apply the polarization and depolarization current (PDC) to the condition monitoring of oil-paper insulation system in power transformers, the influences and elimination method of test temperature on PDC characteristic spectroscopy (PDC-CS) were investigated. Firstly, the experimental winding sample was measured by PDC method at different test temperatures, then the PDC-CS was obtained from the measurement results and its changing rules were discussed, which show that the PDC-CS appears a horizontal mobility with the rise of temperature. Based on the rules, the “time temperature shift technique” was introduced to eliminate the influence of test temperature. It is shown that the PDC-CS at different test temperatures can be converted to the same reference temperature coincident with each other.

7,8-Dihydroxyflavone Protects High Glucose-Damaged Neuronal Cells against Oxidative Stress

  • Cho, Suk Ju;Kang, Kyoung Ah;Piao, Mei Jing;Ryu, Yea Seong;Fernando, Pincha Devage Sameera Madushan;Zhen, Ao Xuan;Hyun, Yu Jae;Ahn, Mee Jung;Kang, Hee Kyoung;Hyun, Jin Won
    • Biomolecules & Therapeutics
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    • v.27 no.1
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    • pp.85-91
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    • 2019
  • Oxidative stress is considered a major contributor in the pathogenesis of diabetic neuropathy and in diabetes complications, such as nephropathy and cardiovascular diseases. Diabetic neuropathy, which is the most frequent complications of diabetes, affect sensory, motor, and autonomic nerves. This study aimed to investigate whether 7,8-dihydroxyflavone (7,8-DHF) protects SH-SY5Y neuronal cells against high glucose-induced toxicity. In the current study, we found that diabetic patients exhibited higher lipid peroxidation caused by oxidative stress than healthy subjects. 7,8-DHF exhibits superoxide anion and hydroxyl radical scavenging activities. High glucose-induced toxicity severely damaged SH-SY5Y neuronal cells, causing mitochondrial depolarization; however, 7,8-DHF recovered mitochondrial polarization. Furthermore, 7,8-DHF effectively modulated the expression of pro-apoptotic protein (Bax) and anti-apoptotic protein (Bcl-2) under high glucose, thus inhibiting the activation of caspase signaling pathways. These results indicate that 7,8-DHF has antioxidant effects and protects cells from apoptotic cell death induced by high glucose. Thus, 7,8-DHF may be developed into a promising candidate for the treatment of diabetic neuropathy.