• Title/Summary/Keyword: Resistance Stress

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Resistance of SOD2-transgenic petunia line to oxidative stress

  • Lee, Su-Young;Han, Bong-Hee;Kim, Yeong-Tae;Kim, Jin-Seog
    • Journal of Plant Biotechnology
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    • v.37 no.4
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    • pp.562-566
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    • 2010
  • SOD2-transgenic $T_3$ petunia line (A2-36-2-1-1-35) was treated with different levels of methyl viologen (MV) to determine its resistance to oxidative stress. Four (4) levels of MV (0, 100, 200, and $400\;{\mu}M$) were applied. The SOD2-transgenic $T_3$ petunia line exhibited a very significant oxidative stress resistance at the highest MV concentration ($400\;{\mu}M$) treatment compared to non-transgenic plant. RNA and protein expression of SOD2 transgene and higher parenchyma cell density in the transgenic petunias exhibiting resistance to oxidative stress proves its contribution to the expression of its resistance to oxidative stress.

Effect of Stress History on CPT-DMT Correlations in Granular Soil (응력이력이 사질토의 CPT-DMT 상관관계에 미치는 영향)

  • Lee, Moon-Joo;Choi, Sung-Kun;Kim, Min-Tae;Lee, Ju-Hyeong;Lee, Woo-Jin
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.730-739
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    • 2010
  • Stress history increases in penetration resistance due to the increase in residual horizontal stress of granular soil. This study analyzes the effect of stress history on the results of CPT and DMT from calibration chamber specimen in OC as well as NC state. Test results show that the normalized cone resistance by mean effective stress correlates well with the relative density and the state parameter, whereas the normalized cone resistance with regard to vertical effective stress is a little affected by stress history. The horizontal stress index($K_D$) in DMT more reflects the influence of stress history on granular soil than the dilatometer modulus($E_D$) and cone resistance($q_c$). The $K_D/K_0$, in which the effect of stress history on $K_D$ is compensated by the at-rest coefficient of earth pressure, $K_0$, is related to relative density, state parameter and the normalized cone resistance by mean effective stress. It is also observed that the normalized dilatometer modulus by mean effective stress($E_D/{\sigma_m}'$) is unique correlated with the state parameter, regardless of stress history.

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Can antioxidants be effective therapeutics for type 2 diabetes?

  • Park, Soyoung;Park, So-Young
    • Journal of Yeungnam Medical Science
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    • v.38 no.2
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    • pp.83-94
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    • 2021
  • The global obesity epidemic and the growing elderly population largely contribute to the increasing incidence of type 2 diabetes. Insulin resistance acts as a critical link between the present obesity pandemic and type 2 diabetes. Naturally occurring reactive oxygen species (ROS) regulate intracellular signaling and are kept in balance by the antioxidant system. However, the imbalance between ROS production and antioxidant capacity causes ROS accumulation and induces oxidative stress. Oxidative stress interrupts insulin-mediated intracellular signaling pathways, as supported by studies involving genetic modification of antioxidant enzymes in experimental rodents. In addition, a close association between oxidative stress and insulin resistance has been reported in numerous human studies. However, the controversial results with the use of antioxidants in type 2 diabetes raise the question of whether oxidative stress plays a critical role in insulin resistance. In this review article, we discuss the relevance of oxidative stress to insulin resistance based on genetically modified animal models and human trials.

A Double Mediating Effect of Resistance and Job Stress between Acceptance and Flourishing in Organizational Change (변화수용성과 번영 간 관계에서 변화저항과 직무스트레스의 이중 매개효과)

  • Lee, Hyun-joo;Jung, Sung-cheol
    • Journal of Venture Innovation
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    • v.4 no.3
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    • pp.89-108
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    • 2021
  • This study purposed to investigate the double mediating effect of the resistance and the job stress between the acceptance and the flourishing in organizational change. The survey has executed on 300 employees. The acceptance of organizational change was positively related to the flourishing, negatively to the resistance of organizational change and the job stress. The resistance of organizational change was positively related to the job stress, negatively to the flourishing. The job stress was negatively related to the flourishing. The resistance of organizational change was meditating the acceptance to change and the job stress, and the acceptance to change and the flourishing. The job stress on the acceptance to change and the flourishing partially mediated as well as the resistance to change and the flourishing. The resistance to change and the job stress double meditated the acceptance to change and the flourishing. The implications, limitations of this study for future research were discussed.

The Effects of Resistance Exercise Program for Elders with Type 2 Diabetes on the Self Care, Stress and HbA1c (저항운동 프로그램이 제 2형 당뇨병 노인의 자가간호, 스트레스 및 당화혈색소에 미치는 효과)

  • Lee, Sun-Woo;Shin, Sung-Rae
    • Korean Journal of Adult Nursing
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    • v.20 no.3
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    • pp.431-442
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    • 2008
  • Purpose: The purpose of this study was to examine the effects of resistance exercise program for elders with type 2 Diabetes on the self care, stress and HbA1c. Methods: Thirty three elders with type 2 Diabetes(18 experimental and 15 control subjects) were selected conveniently among the aged who had been enrolled in a community senior center. The subjects in experimental group participated in a resistance exercise program for 8 weeks. Data were analyzed using the SPSS/Win 12.0. Results: The resistance exercise program showed a statistical difference in self care(t=-4.39, p=.000) and stress(t=2.22, p=.034). However, there was not a statistical difference in HbA1c (F=.556, p=.557), but experimental group had decreased continuously in HbA1c after the program. Conclusion: The resistance exercise program improved self care and reduced the stress in the elders with type 2 Diabetes. Therefore, resistance exercise program can be applied as an effective nursing intervention to promote self care, decrease the stress and to prevent complication for the elders with type 2 Diabetes.

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Dynamic Behaviors of Shelly Sand in Cyclic Simple Shear Test (반복단순전단 시험에 의한 패각질 모래의 동적 거동)

  • Yoon, Yeo-Won;Yoon, Kil-Lim;Choi, Jae-Kwon;Kim, Jae-Kwon;Kim, Seung-Hyun
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.03a
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    • pp.1358-1366
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    • 2006
  • In order to study the effects of shell contents on the liquefaction resistance of the shelly sand, NGI cyclic simple shear tests were performed for the shelly sands with shell contents of 0%, 5%, 10%, 20% and 30% under the effective vertical stress of 50kPa, 100kPa and 150kPa for 40% and 55% of relative density, respectively. Cyclic simple shear test results showed that for the low effective vertical stress, liquefaction resistance increased rapidly with the increase of shell contents in both 40% and 55% relative density. On the other hand, for the high effective vertical stress, the liquefaction resistance increased slightly in 40% relative density whereas the resistance was almost same in 55% relative density. Liquefaction resistance decreased with increasing effective vertical stress for both 40% and 55% relative density. In the same effective vertical stress and shell contents, liquefaction resistance increased with the increase of relative density of sands.

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Arctigenin Inhibits Etoposide Resistance in HT-29 Colon Cancer Cells during Microenvironmental Stress

  • Yoon, Sae-Bom;Park, Hae-Ryong
    • Journal of Microbiology and Biotechnology
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    • v.29 no.4
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    • pp.571-576
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    • 2019
  • Microenvironmental stress, which is naturally observed in solid tumors, has been implicated in anticancer drug resistance. This tumor-specific stress causes the degradation of topoisomerase $II{\alpha}$, rendering cells resistant to topoisomerase $II{\alpha}$-targeted anticancer agents. In addition, microenvironmental stress can induce the overexpression of 78kDa glucose regulated protein (GRP78), which can subsequently block the activation of apoptosis induced by treatment with anticancer agents. Therefore, inhibition of topoisomerase $II{\alpha}$ degradation and reduction in GRP78 expression may be effective strategies for inhibiting anticancer drug resistance. In this study, we investigated the active compound arctigenin, which inhibited microenvironmental stress-induced etoposide resistance in HT-29 cells. Arctigenin was also highly toxic to etoposide-resistant HT-29 cells, with an $IC_{50}$ value of $10{\mu}M$ for colony formation. We further showed that arctigenin inhibited the degradation of topoisomerase $II{\alpha}$ and reduced the expression of GRP78. Thus, these results suggest that arctigenin is a novel therapeutic agent that inhibits resistance to etoposide associated with microenvironmental stress conditions.

The Relationship Between Static Cone Penetration Resistance and the Reference Stress in Sandy Soils (사질토 지반에서의 정적관입저항과 기준응력과의 관계)

  • Baek, Se-Hwan;Lee, Myeong-Hwan;Lee, Won-Je
    • Geotechnical Engineering
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    • v.6 no.4
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    • pp.33-42
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    • 1990
  • In the analysis of the static cone penetration resistance or the point resistance of end bearing piles, the vertical effective stress has been chosen as the reference stress. However many reported experimental results indicate that the cone tip resistance is dependent rather on the in -situ horzontal stress than the vertical effective stress. To clarify this point, published experimental results have been re-evaluated and the laboratory penetration tests have been performed. From the results it is concluded that the cone tip resistance is influenced by both the vertical effective stress and the horizontal effective stress. It is further concluded that the mean normal stress should be used as the reference stress in the analysis.

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A Study of the Relationship between Drinking, Smoking and Stress of Workers by Analyzing Heart Rate Variability (일개 사업장 근로자들의 한방건강검진에서 심박동변이도(HRV) 측정을 통한 음주와 흡연여부에 따른 스트레스 결과 분석)

  • Park, Young-Sun;Kim, Seuk-Jung;Kim, Jong-Dae
    • The Journal of Korean Medicine
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    • v.29 no.1
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    • pp.134-145
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    • 2008
  • Objectives : This study investigated the relationship between drinking, smoking and stress of workers by analyzing heart rate variability. The subjects were workers in the automobile manufacturing industry. Methods : The subjects consisted of 21,239 and 19,999 industrial workers who had received health examination by Korean oriental medicine and submitted questionnaires about drinking history and smoking history, during 8 months from April to November. The subjects were categorized into drinking history and smoking history. The heart rate variability was measured for five minute at rest using SA-3000P (Medicore) and reported stress severity as stress index, stress resistance and fatigue. We analyzed the relationship between drinking, smoking and stress into frequencies, $x^2$-test using the SPSS Ver. 12.0. Results : Regarding the relationship between drinking and stress index orstress resistance, there was no statistically significant difference, but regarding the relationship between drinking and fatigue, the drinker group had a significantly higher level of fatigue than the non-drinker group. There was a statistically significant difference in stress index, stress resistance and fatigue between the current-smoker group and others. Stress resistance of the current-smoker group had lower levels than the non-smoker group or ex-smokers. On the other hand, stress index and fatigue of the current-smoker group had higher levels than the non-smoker group or ex-smokers. Conclusions : The above results revealed that drinking and smoking could put workers under a lot of stress. Smoking workers were especially apt to be under stress and had difficulty in alleviating stress.

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Improvement of Chloride Induced Stress Corrosion Cracking Resistance of Welded 304L Stainless Steel by Ultrasonic Shot Peening

  • Hyunhak Cho;Young Ran Yoo;Young Sik Kim
    • Corrosion Science and Technology
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    • v.23 no.4
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    • pp.266-277
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    • 2024
  • Due to its good corrosion and heat resistance with excellent mechanical properties, 304L stainless steel is commonly used in the fabrication of spent nuclear fuel dry storage canisters. However, welds are sensitive to stress corrosion cracking (SCC) due to residual stress generation. Although SCC resistance can be improved by stress relieving the weld and changing the chloride environment, it is difficult to change corrosion environment for certain applications. Stress control in the weld can improve SCC resistance. Ultrasonic shot peening (USP) needs further research as compressive residual stresses and microstructure changes due to plastic deformation may play a role in improving SCC resistance. In this study, 304L stainless steel was welded to generate residual stresses and exposed to a chloride environment after USP treatment to improve SCC properties. Effects of USP on SCC resistance and crack growth of specimens with compressive residual stresses generated more than 1 mm from the surface were studied. In addition, correlations of compressive residual stress, grain size, intergranular corrosion properties, and pitting potential with crack propagation rate were determined and the improvement of SCC properties by USP was analyzed.