• Title/Summary/Keyword: Stress reaction

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Mechanical Properties and Smoothness of Semiconductive Shield for Power Transmission by Carbon Black Content (카본블랙의 함량에 따른 송전용 반도전 재료의 기계적 특성 및 Smoothness)

  • Lee, Kyoung-Yong;Yang, Jong-Seok;Lee, Kwan-Woo;Choi, Yong-Sung;Park, Dae-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.11a
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    • pp.301-307
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    • 2004
  • To improve mean-life and reliability of power cable in this paper, we have investigated stress-strain and smoothness showing by changing the content of carbon black that is semiconductive additives for underground power transmission. Specimens were made of sheet form with the three of existing resins and the nine of specimens for measurement. Stress-strain of specimens was measured by TENSOMETER 2000. A speed of measurement was 200[mm/min], ranges of stress and strain were $400(Kgf/cm^2)$ and 600[%]. In addition tests of stress-strain were progressed by aging specimens at air oven. Finally we wished to look for protrusion of specimens by using smoothness tester. According to increasing the content of carbon black from this experimental result, yield stress was increased, while strain was decreased. And stress-strain were decreased some after aging because of oxidation reaction of chemical defect. Lastly surface of specimens smoothed generally.

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Effect of Sound Stress on Immune Response (소음 스트레스가 면역반응에 미치는 영향에 관한 실험적 연구)

  • 김금재
    • Journal of Korean Academy of Nursing
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    • v.19 no.2
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    • pp.135-146
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    • 1989
  • This study was undertaken to assess the effect of sound stress on humoral and cellular immune responses to thymus-dependent and independent antigens in mice. After mice were exposed to 4 hr daily sound stessors(83㏈) for 4 days before or after immunization, the primary and / or secondary immune response to sheep red blood cells(SRBC), polyvinylpyrroridone(PVP) or picry1 chloride(TNCB) were assayed. When mice were exposed to sound stressor before or after immunization, delayed-type hypersensitivity reaction and contact sensitivity to TNCB was remarkably depressed compared with those of the unstressed control mice. However, the primary and secondary hemagglutinin response of the stresed mice to SRBC showed a pronounced increase compared with that of the unstressed mice, In contrast to antibody response to SRBC, the primary antibody response of the stressed mic to PVP was almost not detected. surprisingly, the secondary antibody response to PVP of the mice receiving the secondary sound stress was markedly increased when the immune-depressed mice received the secondary immunization with PVP at 46 days after the primary immunization. The susceptibility of mice to intraven-oulsy infected Candida albicans was not changed by the sound stress.

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Dynamic Behavior of a Breasting Dolphin with Various Dolphin Heights and Slopes (돌핀의 높이와 경사에 따른 돌핀의 거동 특성)

  • Yoon, Gyeong-Seug;Cho, Won-Chul;Jo, Chul-Hee
    • Journal of Ocean Engineering and Technology
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    • v.23 no.6
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    • pp.44-52
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    • 2009
  • In this study, the behavior of a breasting dolphin with various dolphin heights and formations in the coastal area of Incheon was investigated. The dynamic deflection, shear stress, and moment of the pile were analyzed using the coefficient of the horizontal subgrade reaction that resulted from loading tests of different DWT (Dead Weight Tonnage). In the case of a vertical pile type dolphin, the deflection, shear stress, and moment increased as the dolphin height increased. In the case of the battered pile type dolphin, small values of shear stress and moment were shown at a low dolphin height, and the characteristics of the dynamic behavior of the dolphin showed that the deflection, shear stress, and moment increased as the pile slope of the dolphin decreased or the DWT increased.

Overexpressed Mitochondrial Thioredoxin Protects PC12 Cells from Hydrogen Peroxide and Serum-deprivation

  • Lee, Yun-Song;Yu, Seung-A
    • The Korean Journal of Physiology and Pharmacology
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    • v.7 no.1
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    • pp.33-37
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    • 2003
  • Oxidative damage to mitochondria is a critical mechanism in necrotic or apoptotic cell death induced by many kinds of toxic chemicals. Thioredoxin (Trx) family proteins are known to play protective roles in organisms under oxidative stress through redox reaction by using reducing equivalents of cysteines at a conserved active site, Cys-X-X-Cys. Whereas biological and physiological properties of Trx1 are well characterized, significance of mitochondrial thioredoxin (Trx2) is not well known. Therefore, we addressed physiological role of Trx2 in PC12 cells under oxidative stress. In PC12 cells, transiently overexpressed Trx2 significantly reduced cell death induced by hydrogen peroxide, whereas mutant Trx2, having serine residues instead of two cysteine residues at the active site did not. In addition, stably expressed Trx2 protected PC12 cells from serum deprivation. These results suggest that Trx2 may play defensive roles in PC12 cells by reducing oxidative stress to mitochondria.

Job Stress Levels in Environment Impact Assessment, and Related Factors Including Expert (환경영향평가 전문가의 직무스트레스 수준 및 관련 요인)

  • Ji, Dong-Ha;Jeon, Hye-Ri;Choi, Soo-Hyun;Son, Bu-Soon;Choi, Mi-Suk
    • Journal of Environmental Health Sciences
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    • v.36 no.5
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    • pp.373-382
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    • 2010
  • A number of recent studies have shown that occupational stress is closely associated with increased fatigue and decreased job satisfaction. This study was designed to assess stress in workers in the field of EIA (environment impact assessment) from July 2009 through september 2009, and questionnaires were uesd to analyze the stress scores and identify the primary factors influencing stress in this occupation. The number of respondents was 272 working in the Capital (Seoul and Kyunggido), Chungcheongdo, Jejudo area. A structured questionnaire was used to evaluate the participants' socio-demographics, job-related factors, health-related behaviors, occupational stress, reaction factor (self-perceived fatigue, job satisfaction) and buffer factor (social support). Occupational stress and self-perceived fatigue were assessed using the Korean Occupational Stress Scale-Short Form (KOSS-SF) and the Multidimensional Fatigue Scale (MFS), respectively. The analysis revealed a strong correlation between occupational stress, job satisfaction, and social support, with occupational stress being associated with an increased risk of fatigue and decreased job satisfaction. In the multiple regression analysis(stepwise), the main factors influencing occupational stress were found to be job satisfaction, supervisor, fatigue, working time, no. of personnel, career. The results of this study suggest that occupational stress is a determinant predictor of self perceived fatigue and job satisfaction. Thus, a strong recommendation is made for a stress management program for reduction of occupational stress, and for the development of relevant experts on the health and quality of life of environment impact assessment workers.

Chemical and Free Radical-scavenging Activity Changes of Ginsenoside Re by Maillard Reaction and Its Possible Use as a Renoprotective Agent

  • Yamabe, Noriko;Song, Kyung-Il;Lee, Woo-Jung;Han, Im-Ho;Lee, Ji-Hwan;Ham, Jung-Yeob;Kim, Su-Nam;Park, Jeong-Hill;Kang, Ki-Sung
    • Journal of Ginseng Research
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    • v.36 no.3
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    • pp.256-262
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    • 2012
  • Reactive oxygen species play critical role in kidney damage. Free radical-scavenging activities of Panax ginseng are known to be increased by heat-processing. The structural change of ginsenoside and the generation of Maillard reaction products (MRPs) are closely related to the increased free radical-scavenging activities. In the present study, we have demonstrated the Maillard reaction model experiment using ginsenoside Re and glycine mixture to identify the renoprotective effect of MRPs from ginseng or ginsenosides. Ginsenoside Re was transformed into less-polar ginsenosides, namely Rg2, Rg6 and F4 by heat-processing. The free radical-scavenging activity of ginsenoside Re-glycine mixture was increased in a temperature-dependant manner by heatprocessing. The improved free radical-scavenging activity by heat-processing was mediated by the generation of antioxidant MRPs which led to the protection of LLC-PK1 renal epithelial cells from oxidative stress. Although the free radical scavenging activities of less-polar ginsenosides were weak, they could protect LLC-PK1 cells from oxidative stress. Therefore, MRPs and less-polar ginsenosides contributed to the combined renoprotective effects against oxidative renal damage.

The analysis of stress reactions ana coping patterns of cancer patients who perceived stress by radiotherapy. (방사선요법을 받는 암환자의 스트레스 지각에 따른 반응과 대체유형의 분석)

  • BANG DONG WAN;KIM JIN SU;PARK GIL YONG;SON MI SUK
    • The Journal of Korean Society for Radiation Therapy
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    • v.13 no.1
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    • pp.1-13
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    • 2001
  • I. Purpose This study is performed to encourage cancer patients to identify, relieve and effectively overcome the stress caused by radiotherapy, by analyzing stress reactions and coping patterns of cancer patients who perceived stress due to radiotherapy. II. Materials & Methods The study group was composed of 85 cancer patients of the age 20 or higher who were undergoing radiotherapy in four hospitals located in Seoul and Kyonggi-do. The survey questionnaire was used, which had 161 questions inquiring respondents of general status, perceived stress, stress reactions and coping patterns. The surveyed data were analyzed by a SAS program, which employed descriptive statistics. Pearson Correlation Coefficient, t-test, ANOVA and Stepwised Multiple Regression. III. Results The stress perception and reaction rates were low in cancer patients comparing to patients of the other study. In the coping patterns. the problem-focused coping patterns were significantly higher than emotion-focused coping patterns. The statistically meaningful differences were observed in the stress perception and reactions depending on the time of diagnosis and perceived health level. As for the problem-focused coping patterns, significant differences were found depending on age, marital status, education, income and the number of family members as well as perceived health level of patients. The level of perceived stress and that of stress reactions was found to have positively significant correlation(r=.764, p<.001) while the perceived stress and the problem-focused coping patterns was correlated negatively (r=-.288, p<.01). The stress reactions and the problem-focused coping patterns was found to have negatively significant correlation(r=-.289, p<.01). IV. Conclusion The problem-focused coping behavior, which cooperated with doctors, technologists, nurses and families of cancer patients, is advisable for the cancer patients to overcome uncertainty and uneasiness by effectively release the stress.

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Biochemical Characterization of the Dual Positional Specific Maize Lipoxygenase and the Dependence of Lagging and Initial Burst Phenomenon on pH, Substrate, and Detergent during Pre-steady State Kinetics

  • Cho, Kyoung-Won;Jang, Sung-Kuk;Huon, Thavrak;Park, Sang-Wook;Han, Ok-Soo
    • BMB Reports
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    • v.40 no.1
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    • pp.100-106
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    • 2007
  • The wound-inducible lipoxygenase obtained from maize is one of the nontraditional lipoxygenases that possess dual positional specificity. In this paper, we provide our results on the determination and comparison of the kinetic constants of the maize lipoxygenase, with or without detergents in the steady state, and characterization of the dependence of the kinetic lag phase or initial burst, on pH, substrate, and detergent in the pre-steady state of the lipoxygenase reaction. The oxidation of linoleic acid showed a typical lag phase in the pre-steady state of the lipoxygenase reaction at pH 7.5 in the presence of 0.25% Tween-20 detergent. The reciprocal correlation between the induction period and the enzyme level indicated that this lag phenomenon was attributable to the slow oxidative activation of Fe (II) to Fe (III) at the active site of the enzyme as observed in other lipoxygenase reactions. Contrary to the lagging phenomenon observed at pH 7.5 in the presence of Tween-20, a unique initial burst was observed at pH 6.2 in the absence of detergents. To our knowledge, the initial burst in the oxidation of linoleic acid at pH 6.2 is the first observation in the lipoxygenase reaction. Kinetic constants (Km and kcat values) were largely dependent on the presence of detergent. An inverse correlation of the initial burst period with enzyme levels and interpretations on kinetic constants suggested that the observed initial burst in the oxidation of linoleic acid could be due to the availability of free fatty acids as substrates for binding with the lipoxygenase enzyme.

Effects of Learning Motivation on the Stress Coping Style and Stress of Test (학습동기가 시험 스트레스와 스트레스 대처 양식에 미치는 영향)

  • Jang, Chel;Lee, Eunhye;Cheon, Jisu
    • Journal of The Korean Society of Integrative Medicine
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    • v.2 no.2
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    • pp.89-96
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    • 2014
  • Purpose : In this study, we selected three research subjects to attempt to clear learning motivation of college students is what impact the stress coping style and stress test. First, age, gender, the future career after graduation, the presence or absence of part-time job is, its impact on learning motivation. Second, learning motivation is what effect the stress of the test. Third, based on the motivation of learning, how deal pursuing efforts form the social support, the center of the problem-solving approach, seeking to avoid the reaction to stress how different form. Methods : K University occupational therapy and one, two, three grade 100 students (male 22 people, female 78) to target age, sex, and after graduation, part-time status, motivation, stress, stress coping style questionnaire for distribution and was written. Results : First of all, women's social support form graduation course, more robust than pursue blank after the synchronization uncertainty and stress, and graduated from the trading center and avoid the use of career, more form. Second, motivation and stress test, a difference between the notice could not see. Third, the higher the motivation of learning, problem-solving, Action form to the center to use as many as you, but avoid using too much in the center form is addressed. Conclusion : As a result of the study that came out of the course after graduating from ensure that learning motivation is high, the more the uncertainty, the more to cope with stress in the center of the form to avoid form address was used. Because of this, the student careers after graduation, to make sure that can help you to compare efforts over is believed to be necessary.

Application of Stress Hormones in Saliva in Research of Orofacial Pain Related with Stress (스트레스와 관련된 구강안면통증의 연구에 있어서 타액내의 스트레스호르몬의 활용)

  • Ryu, Ji-Won;Yoon, Chang-Lyuk;Ahn, Jong-Mo
    • Journal of Oral Medicine and Pain
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    • v.32 no.2
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    • pp.201-210
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    • 2007
  • Many diseases occur by stress or effect of stress. The basis for using hormones in research of stress is the observation that most systems in the body show changes during stress and that hormonal markers in these changes are related with stress. Conceptually, the central role of sympathetic nervous system(SNS) and hypothalamus-pituitary-adrenal(HPA) axis activity in stress provides copious justification for measuring hormonal changes. Catecholamines like epinephrine and norepinephrine, cortisol, testosterone and growth hormone and so on show sensitive reaction to stress. The major advantage of salivary sample to stress research is that its sampling technique can be performed in non-stressful conditions and without physical restraint and ethical problems. Because hormone levels in saliva is a good reflection of hormone levels in plasma, application of stress hormones in saliva is very useful for research of orofacial pain related with stress.