• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1518-1520
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• 2008

Recent clinical studies have shown that computer navigation for total knee arthroplasty (TKA) provides improved component alignment accuracy. However, femoral stress fracture after computernavigated TKA have been reported due to the pin hole and we hypothesized that osteoporosis would be one of the key factors in pin hole fracture after computer-navigated TKA. We investigated the von-Mises stress around the femoral pin-hole for different elastic modulli and ultimate stresses and four different pin penetration modes to understand the aging effect on femoral stress fracture risk after computer-navigated TKA by finite element analysis. In this study, aging effect was shown to increase the femoral stress fracture risk for all pin penetration modes. Especially, aging effect was shown dramatically in the transcortical pin penetration mode.

• The Korean Journal of Emergency Medical Services
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• v.23 no.2
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• pp.33-42
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• 2019

Purpose: This study aimed to identify the effects of post-traumatic stress disorder intervention programs on firefighters through a meta-analysis. Methods: Seven studies were selected for meta-analysis. The overall average effect size, effect sizes for each intervention variables, and publication bias were analyzed using Comprehensive Meta-Analysis(CMA) version 2.0 (Biostat, Englewood, NJ, USA). Results: Post-traumatic stress disorder intervention programs were found to have a very low, not statistically significant effect (effect size=-.171, confidence interval=-0.361~0.019, Z=-1.768, p>.05). However, these programs was less than 50 (effect size=-.622). Conclusion: The results of this study suggest that further research on the effects of post-traumatic stress disorder intervention among firefighters is needed in order to develop more effective programs.

• The Korean Journal of Emergency Medical Services
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• v.21 no.3
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• pp.109-120
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• 2017

Purpose: The purpose of the study was to investigate the mediating effects of self-efficacy on the relationship between job stress and turnover intention of paramedics in hospitals. Methods: A self-reported questionnaire was completed by 209 paramedics in hospitals from September 4 to 24, 2015. Data were analyzed by descriptive statistics, t-test, ANOVA, Pearson's correlation coefficients, and multiple regression analysis using Baron & Kenny's 3 step procedure. Indirect effect was confirmed with Sobel test using SPSS/Win 22.0 program. Results: There were negative relationships between job stress, self-efficacy, and turnover intention (r=-.509, p<.001). There was a negative relationship between job stress and self efficacy (r=-.821, p<.001). The self-efficacy and turnover intention showed a positive relationship (r=.636, p<.001) with job stress and turnover intention. Concerning the mediated effect of self efficacy on job stress and turnover intention, the influence of job stress at step 2 on turnover intention was significant (B=1.207, p<.001), while job stress at step 3 had significant influence on turnover intention (B=.474, p<.001). The mediated effect of self-efficacy on job stress and turnover intention showed significant partially mediated effect of self-efficacy (z=7.100, p<.001). Conclusion: Improvement of self-efficacy and job stress was effective at decreasing turnover intention in paramedics in hospitals.

• Journal of Environmental Science International
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• v.20 no.12
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• pp.1509-1519
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• 2011

The protective effect of nitric oxide (NO) on the antioxidant system under paraquat(PQ) stress was investigated in leaves of 8-week-old lettuce (Lactuca sativa L.) plants. PQ stress caused a decrease of leaf growth including leaf length, width and weight. Application of NO donor, sodium nitroprusside (SNP), significantly alleviated PQ stress induced growth suppression. SNP permitted the survival of more green leaf tissue preventing chlorophyll content reduction and of higher quantum yield for photosystem II than in non-treated controls under PQ exposure, suggesting that NO has protective effect on chloroplast membrane in lettuce leaves. Flavonoids and anthocyanin were significantly accumulated in the leaves upon PQ exposure. However, the rapid increase of these compounds was alleviated in the SNP treated leaves. PQ treatment resulted in lipid peroxidation and induced accumulation of hydrogen peroxide ($H_2O_2$) in the leaves, while SNP prevented PQ induced increase in malondialdehyde (MDA) and $H_2O_2$. These results demonstrate that SNP serves as an antioxidant agent able to scavenge $H_2O_2$ to protect plant cells from oxidative damage. The activities of two antioxidant enzymes that scavenge reactive oxygen species, superoxide dismutase (SOD) and catalase (CAT) in lettuce leaves in the presence of NO donor under PQ stress were higher than those under PQ stress alone. Application of 2-(4-carboxyphenyl)-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO), a specific NO scavenger, to the lettuce leaves arrested SNP mediated protective effect on leaf growth, photosynthetic pigment and antioxidant systems. However, PTIO had little effect on lettuce leaves under PQ stress compared with that of PQ stress alone. The obtained data suggest that the damage caused by PQ stress is in part due to increased generation of active oxygen by maintaining increased antioxidant enzyme activities and SNP protects plants from oxidative stress. From these results it is suggested that NO might act as a signal in activating active oxygen scavenging system that protects plants from oxidative damage induced by PQ stress and thus confer PQ tolerance.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.135-135
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• 2022

For abnormal weather disaster and building constructions, the shading stress could occur in crops more often. Those shading stress can effect on rice growth characters. Therefore, we investigated the shading effect on rice growth characters. Shading treatments were treated using shading screen as 35, 55, 75 and 100%. To check the shading effect on rooting after transplanting, shading stress treated after transplanting for 20 days as 35, 55 and 75%, And 35, 55, 75 and 100% of shading were treated 60 days after transplanting to check the growth characters. After transplanting, the shading stress effected on leaf and root growth. At 19 days after transplanting, leaf number reduced by shading stress. In 35, 55 and 75% shading stress, the leaf number reduced as 0.38, 0.45 and 0.9 respectively compared to control treatment. And root length was also reduced as 0.39, 0.6 and 1.93 cm respectively compared to control treatment. The plant height was slightly increased in 35 and 55% and reduced in 100%. Leaf growth speed per day was reduced as 0.0167 according to shading stress. And root growth speed also reduced as 0.0426 according to shading stress. The shading stress during vegetative stage effected on plant height and tiller number. In 35, 55 and 75% of shading stress, the plant height was slightly increased but it was reduced in 100%. Tiller number was significantly reduced by shading stress. According to 10% of shading stress, about 7% of the tiller number was reduced. However, leaf color did not change by the shading stress. The leaf area in 2^nd to 4nd leaf from new leaf reduced as 297 and 1044 in 75 and 100% of shading stress and increased as 70 and 99 in 35 and 55%. These leaf area change was affected by both the length and width of the leaf.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.26 no.3
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• pp.77-86
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• 2018

Stress is the main source of a human error or can potentially contribute to it. Recently, the rate of accidents which is associated with human factors among the total aircraft accidents is showing a tendency of gradual increase. In order to prevent the accidents related to human factors, stress mitigation of the mission personnel is highly required. In this study, a 'stress cognitive alteration' technique, which is one of the stress relief methods, is applied to the Air Force pilots to verify if the technique is effective in reducing stress. The 'stress cognitive alteration' technique is comprised of two parts: a positive function of stress and a process to positively alter the physical, psychological response to stress. As a result of the application, it is found that this technique has an effect of reducing stress of the pilots under a relatively high level of stress.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.04a
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• pp.101-105
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• 2000

In cold forging die the shrink fitting is generally used to decrease stress and increase die life. In this paper we have studied about the effect of fitting type, When the die insert is splitted into several pieces the maximum stress could be decreased as much as 50~70% The fitting angle could be selected to minimize the maximum stress and the variation of stress on loading and unloading, . In F, E.M result in case 3。 fitting angle the maximum and variation of stress may be minimized.

• Journal of Haehwa Medicine
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• v.10 no.1
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• pp.489-494
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• 2001

To determine the preventive effect of Samulanshintang (SA) on stress, we investigated the physiological change of rats which were applied immobilization stress. For immobilization stress, rats were placed in restrainer for 12 hours a day for 3 days. During application of stress, body weight of rats was measured. After sacrifice, 4 organs were taken for measurement of organ weight. Brain was homogenated and its catecholamine and serotonin contents were measured with HPLC. In our study, stress mainly induced increase of concentration of neurotransmitters in brain without other significant physical change of rats. SA inhibited stress induced changes of neurotransmitter content in brain.

• The Plant Pathology Journal
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• v.27 no.3
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• pp.249-256
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• 2011

Tall fescue (Schedonorus phoenix Scop.) is resistant to abiotic and biotic stresses through a symbiotic relationship with Neotyphodium coenophialum. However, this endophyte has been considered detrimental since it produces toxic alkaloids to animals. It is vital to understand mutuality between these two to maximize positive impact of the endophyte on agri-ecosystem. Little research has been conducted on endophyte transmission mechanism in planta. To provide basic information related to endophyte transmission, an experiment was conducted to examine the effect of endophyte genotype and water stress on endophyte transmission by imposing soil moisture deficits at different stages of panicle development. There was water stress effect on endophyte frequency but not on concentration, whereas endophyte genotype significantly influenced endophyte concentration in pseudostem of tall fescue at boot stage. Reproductive tillers showed greater endophyte frequency and concentration. Endophyte frequency in florets or seeds depended on position within panicle. There was no drought effect on endophyte concentration, but showed the effect of endophyte genotype on endophyte concentration in florets and seeds. Overall endophyte concentration in seeds was higher. From this study, we may conclude that although water stress reduced endophyte frequency in vegetative tiller, water stress does not have effect on endophyte transmission, suggesting that drought is not an important factor controlling the endophyte transmission from plant to seed. Endophyte genotype and seed position in a panicle affected endophyte transmission, indicating that these two factors are involved in endophyte transmission and may determine seed transmission of endophyte in tall fescue.

• Journal of Agricultural Extension & Community Development
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• v.21 no.3
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• pp.1-23
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• 2014

This study aimed to verify the mediating effect of hope between acculturative stress and depression of immigrant women for marriage in Chungcheongnam-do, Korea. The data were collected from 580 immigrant women for marriage and were analysed by using descriptive statistics, correlation analysis and structural equation. The main results were as follows. There was a positively direct effect between acculturative stress and depression. But hope had negatively direct effect on acculturative stress and depression. Also, the study verified that there was the mediating effect of hope between acculturative stress and depression of immigrant women. Implications for the suggestions to enhance the hope level of immigrant women and future research were discussed.