• Journal of Nutrition and Health
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• v.34 no.5
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• pp.525-531
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• 2001

The present study investigated the protective effects of green tea against acute ethanol-induced lipid peroxidation and the change of antioxidative enzyme activities in various regions of rat brain : cortex, cerebellum, striatum and hippocampus. The following parameters were examined : malondialdehyde(MDA) levels and activities of superoxide dismutase(SOD), catalase and glutathione peroxidase(GSH-Px). Male Sprague-Dawley rats were given the experimental containing 1% green tea powder or control diet for 4 weeks, and at the end of feeding diet group received acute ethanol(5g/kg body weight) or equicaloric sucrose solution intragastrically. Green tea powder significantly decreased MDA levels in the striatum compared to control-non alcohol treated group to 1% green tea-non alcohol treated group without altering the antioxidative enzyme activities. Green tea resulted in a significant increase in GSH-Px activities in the hippocampus compared to either control-non alcohol treated group(0.043units/mg protein) or 1% green tea-non alcohol treated group(0.071units/mg protein). In conclusion, these results suggest that moderate consumption of green tea leaves can exert protective effects against ethanol-induced oxidative stress in brain regions, by reducing MDA concentrations in the striatum and enhancing GSH-Px activities in the hippocampus. (Korean J Nutrition 34(5) : 525∼531, 2001)

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.4
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• pp.31-43
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• 2022

In this study, we estimated the monthly FDSI (Flash Drought Stress Index) for assessing flash drought on South Korea using AMSR2(Advanced Microwave Scanning Radiometer 2) satellite-based soil moisture footprints. We collected the AMSR2 soil moisture and climate-land surface data from April to November 2018 for analyzing the monthly FDSI values. We confirmed that the FDSI values were high at the regions with the high temperature/evapotranspiration while the precipitation is relatively low. Especially, the regions which satisfied an onset of flash drought (FDSI≧0.71) were increased from June. Then, the most of regions suffered by flash drought during the periods (July to August) with the high temperature and evapotranspiration. Additionally, the impacts of landuse and slope degree were evaluated on the monthly FDSI changes. The forest regions that have the steep slope degree showed the relatively higher FDSI values than the others. Thus, our results indicated that the the slope degree has the relatively higher impact on the onset and increasing of flash drought compared to the others.

• The Korea Journal of Herbology
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• v.22 no.2
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• pp.127-135
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• 2007

Objective : Investigation of the anti-stress effects of Sihosogansan Methods : Passive avoidance test(PAT) was performed after applying immobilization stress in water to rats. Also, forced swimming test(FST) was performed to another rats and after FST, the degree of Tyrosine Hydroxylase(TH) expression was measured with immunohistochemical method in the regions of locus coeruleus(LC) and ventral tegmental area (VTA). Results : In the PAT after immobilization stress in water, response latency was significantly increased in the Sihosogansan(400mg/kg) group in comparison with the control group. In the FST, immobility was significantly decreased in the Sihosogansan groups (100mg/kg, 400mg/kg), comparing with the control group. Stress-induced TH increases were suppressed in the Sihosogansan groups (100mg/kg, 400mg/kg) at the LC and the VTA region respectively. Conclusion : Sihosogansan can improve memory ability of rats, reduce behavior of depression in rats, decrease TH-immunoreactive cells at the LC and VTA region in rat, and it may be concluded that Sihosogansan has significant effect in reducing stress.

• Journal of Korean Public Health Nursing
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• v.26 no.3
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• pp.518-531
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• 2012

Purpose: This study was conducted in order to develop and test a measurement for assessment of stress of female marriage immigrants in Korea. Methods: Forty four preliminary items were initially developed based on literature review and focus group interviews. Those items were evaluated by experts for content validity, resulting in six factors and 26 items. The 26 items were translated into Chinese, Vietnamese, and English by professional translators and were reviewed by native speakers of each language who are fluent in Korean. For testing validity and reliability, data were collected from 323 female marriage immigrants residing in five regions in Korea. Results: As a result of item analysis, 25 items were selected. Factor analysis yielded 21 items in four factors, including 1) household economic 2) parenting and discrimination 3) cultural and 4) emotional stressors, explaining 61.3% of the total variance of stress of female marriage immigrants in Korea. The Cronbach's alpha reliability coefficient was .903 for the overall instrument and .692-.892 for four factors. Conclusion: Measurement of stress for female marriage immigrants in Korea has high validity and reliability. Therefore, this measurement may be utilized for systematic assessment of stress and for identification of areas of support for female marriage immigrants in Korea.

• The Journal of Advanced Prosthodontics
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• v.5 no.4
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• pp.434-439
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• 2013

PURPOSE. The aim of the present study was to evaluate the effects of posts with different morphologies on stress distribution in an endodontically treated mandibular premolar by using finite element models (FEMs). MATERIALS AND METHODS. A mandibular premolar was modeled using the ANSYS software program. Two models were created to represent circular and oval fiber posts in this tooth model. An oblique force of 300 N was applied at an angle of $45^{\circ}$ to the occlusal plane and oriented toward the buccal side. von Mises stress was measured in three regions each for oval and circular fiber posts. RESULTS. FEM analysis showed that the von Mises stress of the circular fiber post (426.81 MPa) was greater than that of the oval fiber post (346.34 MPa). The maximum distribution of von Mises stress was in the luting agent in both groups. Additionally, von Mises stresses accumulated in the coronal third of root dentin, close to the post space in both groups. CONCLUSION. Oval fiber posts are preferable to circular fiber posts in oval-shaped canals given the stress distribution at the postdentin interface.

• Journal of Mechanical Science and Technology
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• v.18 no.2
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• pp.221-229
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• 2004

In this work, an elastic-plastic stress analysis has been conducted for silicon carbide fiber reinforced magnesium metal matrix composite beam. The composite beam has a rectangular cross section. The beam is cantilevered and is loaded by a single force at its free end. In solution, the composite beam is assumed perfectly plastic to simplify the investigation. An analytical solution is presented for the elastic-plastic regions. In order to verify the analytic solution results were compared with the finite element method. An rectangular element with nine nodes has been choosen. Composite plate is meshed into 48 elements and 228 nodes with simply supported and in-plane loading condations. Predictions of the stress distributions of the beam using finite elements were overall in good agreement with analytic values. Stress distributions of the composite beam are calculated with respect to its fiber orientation. Orientation angles of the fiber are chosen as $0^{circ},\;30^{circ},\;45^{circ},\;60^{circ}\;and\;90^{circ}$. The plastic zone expands more at the upper side of the composite beam than at the lower side for $30^{circ},\;45^{circ}\;and\;60^{circ}$ orientation angles. Residual stress components of ${\sigma}_{x}\;and \;{\tau}_{xy}$ are also found in the section of the composite beam.

• The Korean Journal of Community Living Science
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• v.26 no.3
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• pp.551-563
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• 2015

This study examines the mediating effects of social support on 1) the relationships between acculturative stress and depression/anxiety and 2) the relationships between emotional control and depression/anxiety in children from multicultural families. Pearson's correlations between variables were analyzed, and hierarchical regression analyses were conducted to identify direct and indirect effects of acculturative stress, emotional control, and social support on children's depression/anxiety. The sample included a total of 199 primary school students in grades 3 to 6 who lived in the Gwangju or Chonnam regions of Korea. First, there were positive correlations between acculturative stress and depression/anxiety and negative correlations between emotional control and social support. Second, social support from both peers and teachers partially mediated the relationships between acculturative stress and depression/anxiety. Third, social support from peers fully mediated the relationships between emotional control and depression/anxiety, and that from teachers partially mediated these relationships. The results suggest that social support from peers and teachers may reduce depression/anxiety in multicultural children as a mediating variable.

• The Korean Journal of Community Living Science
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• v.26 no.3
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• pp.565-573
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• 2015

This study examines the relationships between stress and eating habits of adolescents based on the assumption that adolescents require large amounts of nutrients and that eating habits affect their physical development, academic achievement, and emotional development. For this purpose, 213 adolescents in Gangwondo, Korea, were surveyed. Many studies have reported that stress causes changes in eating habits and affects health status. Based on the dietary action guide scores according to stress categories, eating instant foods less was significant (p<0.001), eating fast foods less was significant (p<0.05), and have soft drinks less was significant (p<0.001). The results suggest the importance of balanced nutrition based on the formation of right dietary habits for adolescents. Good nutrition can be determined through right knowledge of nutrition and dietary habits, and right dietary habits can improve health and physical development as well as mental and emotional stability. The analysis did not compare other regions, and therefore any generalization of the results should be made with caution. However, the results offer important insights into stress among adolescents for their effective counseling.

• BMB Reports
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• v.31 no.2
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• pp.117-122
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• 1998

Changes of lipocortin 1 (LC1) in the brain induced by immobilization stress were investigated in rats. Rats were immobilized for 0,1,2,3,4, and 5 h, and the brain slices were immunostained with anti-human LC1 antibodl (anti-LC1). Immunoreactivity of LCI (iLC1) was most prominent in neuronal cell bodies and processes of hippocampal CA regions and dentate gyrus. At rest without stress, most of the LC1 in the neuron located in the cytoplasm with the nuclei exhibiting relatively scarce immunoreactivity. Immobilization stress changed this intracellular distribution of LC1 by increasing nuclear LC1. The change was apparent in 1 h and reached the peak by 3 h. However, by 5 h of immobilization, the distribution pattern returned to that of the resting state. This transient nuclear translocation of LC1 was most prominent in $CA_1$ pyramidal neurons, and was not observed in areas other than the hippocampus. Adrenalectomy abolished this transient translocation of LC1. The roles of hippocampal LC1 as a mediator of glucocorticoid feedback signal and/or as an intracellar stress signaling protein could be suggested.

• Journal of Welding and Joining
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• v.5 no.3
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• pp.53-61
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• 1987

Post weld heat treatment(PWHT) is usually carried out to remove the residual stress and to improve the microstructure and mechanical properties of welded joints. By the way, welding structure transformed owing to PWHT and reheating for repair loads the random cycles fatigue as offshore welding structure of constant low cycle fatigue as pressure vessel, and then, pre-existing flaws or cracks exist in a structural component and those cracks grow under cyclic loading. Therefore, the effects of PWHT and stress ratio on fatigue crack growth behaviors were studied on the three regions such as HAZ, sub-critical HAZ and deposit metal of welded joints in SM53 steel. Fatigue crack growth behavior of as-weld depended on microstructure and fatigue crack growth rate of HAZ was the lowest at eac region, but after PWHT it was somewhat higher than that of as-wel. In case of applying the stress($10kg/mm^2$) during PWHT, fatigue crack growth resistance tended to increase in the overall range of .DELTA.K.