• Science of Emotion and Sensibility
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• v.4 no.2
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• pp.33-38
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• 2001

This analysis has been projected as a preliminary analysis to develop the therapy program for people who is suffering from stress disorder after car accident such as sense of fear or anxiety using virtual reality. The analysis verified the effect of driving scenario which is core technology of stress disorder program and of anxiety reduction training such as relaxation training through clients. The relaxation training has been tested to 8 people; 7 normal and 1 sufferer from car accident presenting them 3 different types of driving scenarios. As a result, relaxation training was effective but, it was not statistically good enough although it showed incensement of uneasiness by each different driving scenario. In spite of normal clients, it is interesting that anxiety lever after relaxation training using VR is lowered, but this result need to verify to client suffering real car accident.

• The Korean Journal of Rheology
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• v.11 no.2
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• pp.82-90
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• 1999

Electrorheological(ER) fluid is a material that shows the dramatic change of rheological properties under an electric field and responds reversibly in a few milliseconds. ER fluid's response to an electric field along with its fast switching capability allows ER devices to be precisely controlled. The real application with ER fluid, however, has many limitations to be overcome; temperature fluctuation, moisture, dust, aggregation, precipitation, and low yield stress, for example. The magnitude and the characteristics of yield stress of ER fluid plays an important role in practical applications. In this research, a dynamic simulation on the squeezing flow of the ER fluid was carried out. Numerical simulation on isolated chains was performed to find out the effect of hydrodynamic and electrostatic force depending on the chain location, the squeezing rate, and the chain structure. Suspension model that is composed of a large number of particles was also investigated. The increase of normal stresses as well as the existence of a yield stress at an earlier stage could be observed, and the effective control of the normal stresses could be achieved at an optimal condition of the hydrodynamic force and the electrostatic force.

• Journal of The Korean Society of Integrative Medicine
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• v.6 no.3
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• pp.11-16
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• 2018

Purpose: Stress tends to cause sympathetic hyperactivity and increase blood cortisol levels. The vagus nerve is a parasympathetic nerve that is involved in relaxing the body. The purpose of this study was to investigate the effects of electrical stimulation of the vagus nerve on stress hormone (cortisol) levels and heart rate variability (HRV) in humans. Methods: A total of 10 healthy subjects participated in the pilot experiment. All subjects underwent electrical vagus nerve stimulation for 20 minutes in the cymba conchae of the left ear. An electro cardiogram meter was used to measure HRV. Blood samples were collected and analyzed for cortisol levels. The standard deviation of all normal N-N intervals (SDNN), root mean square of successive differences (RMSSD), low frequency, high frequency, and cortisol levels were compared in pre and post mean values after the intervention. Data were analyzed using the Wilcoxon's signed-rank test. Results: Coritsol levels were observed to decrease after vagus nerve electrical stimulation. The mean SDNN and RMSSD values were increased after the intervention, but not significantly. Conclusion: Vagus nerve electrical stimulation has been shown to increase the ability of the parasympathetic nerve to adapt to upward regulation and stress. Vagus nerve electrical stimulation could thus be an effective treatment for modern social psychological stress control.

• Women's Health Nursing
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• v.18 no.3
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• pp.180-189
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• 2012

Purpose: The purpose of this study was to evaluate the effects of clinical practice and simulation-based practice for obstetrical nursing in terms of self-efficacy, practice satisfaction, and practice stress. Methods: A non-equivalent control group post test design was used. The participants were 171 junior nursing students, 103 in the experimental group, and 68 in the control group. Simulation-based practice consisted of nursing assessment during labor, nursing assessment and intervention for normal and high risk mother, nursing education for mother and family during labor, and open lab. The experimental group participated in simulation-based practice for two days and the control group participated in clinical practice at delivery room for two weeks. Results: The experimental group showed higher level of self-efficacy (p= .043), practice satisfaction (p<.001) and practice stress (p=.003) compared to the control group. Conclusion: Simulation-based practice is an effective learning method for obstetrical nursing and can be used as the alternative for clinical practice. However, stress management strategies are needed for simulation-based practice.

• Journal of the Korean Society of School Health
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• v.20 no.2
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• pp.91-102
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• 2007

Purpose: This study was performed to determine the levels of psychosocial distress among high school students to reveal the various related factors. Methods: Self-administered questionnaires were administered between June 1st and July 31th, 2006, to 992 different high school students in Daejeon City. The survey items included questions concerning the subjects' family and school life characteristics, health-related behaviors, sense of self-esteem, and locus of control. Results: The results showed that 27.8% of the subjects were categorized as high risk stress, 66.6% as latent stress, and 5.5% as normal. The level of psychosocial distress was found to be influenced by various related factors such as family and school life characteristics, health-related behaviors and personality traits (locus of control, self-esteem). Conclusion: The above results of the study suggest that the more stresses the high school students felt, the higher the correlation with self esteem and self control. Therefore, it is required that there be more development of programs designed towards harmonizing human relationships, promoting regular life styles and positive self perceptions; as well as building self confidence and assisting in course selection. Also, there is a need for further research and education in accessing effective strategies for coping with stress.

• Journal of Nutrition and Health
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• v.28 no.5
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• pp.375-386
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• 1995

This study was designed to investigate the changes in energy substrates, glucose and non-esterified fatty acid(NEFA), and fatty acid compositions in serum, following physiolgical stress in rats fed diets containing various fatty acids. Forty two Sprague-Dawley strain male rats, weighing 108$\pm$2.1g, were fed 3 different experimental diets for 4 weeks. The diets were composed of 105 fat(w/w) of either corn oil(CO;18:2 n6:57%), plant perilla oil(PO;18:3 n3:59%), or tuna fish oil(FO;20:5 n3:17%%, 22:6 n3:19%). After 4 weeks of feeding, each group wa subdiveided into (a) control, (b) 2 min swim in ice-cold water. Animals wer decapitated 20min after commencing the swim; trunk blood, brain, liver and epididymal fat pad were obtained. The levels of serum corticosterone, glucose, NEFA, triglyceride, fatty acid compositions, brain serotonin and 5-hydroxyindoleacetic acid were determined. Basal levels of corticosterone na NEFA of serum were significantly lower in fish oil fed animals than those of any other oil fed animals. Compared to either perilla oil-fed or corn oil-fed rats, cold swim stress in fish oil fed rats produced significantly smaller NEFA and larger corticosterone responses. However, there was no significant difference in basal levels of serum glucose. Stress increased serum glucose levels slightly, and the amount of increment was larger in fish oil rats than those of any other oil fed rats than those of any other oil fed rats, although all the values were normal level. Dietary fats and stress did not affect serotonin metabolism. In additions, the composition of fatty acids in serum was significantly affected by the dietary compostion of fatty acids and stress. Stress induced decreases in monounsaturated fatty acid and non-polyunsaturated fatty acid concentration in either perilla oil fed or fish group, but did not in corn oil fed group. Stress resulted in changes in fatty acid metabolism similar to that associated with essential fatty acid(EFA) dificiency, when feeding animals n-3 fatty acids in diet. In conclusion, feeding fish oil was more effective to decrease NEFA in serum than feeding perilla oil or corn oil and improved lipid metabolism, when the rats were maintained in normal or exposed to stressful environment. However, the fact that feeding diet containing n-3 fatty acids decreased EFA status under stress suggests that the requirement of n-6 PUFA should be increased in these groups.

• Journal of applied mathematics & informatics
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• v.26 no.3_4
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• pp.811-818
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• 2008

Biological systems with both protein-protein and protein-gene interactions can be modeled by differential equations for concentrations of the proteins with time-delay terms because of the time needed for DNA transcription to mRNA and translation of mRNA to protein. Values of some parameters in the mathematical model can not be measured owing to the difficulty of experiments. Also values of some parameters obtained in a normal stress condition can be changed under pathological stress stimuli. Thus it is important to find the effective way of determining parameters values. One approach is to use optimization algorithms. Here we construct an optimal system used to find optimal parameters in the equations with nonnegative time delays and apply this optimization result to the Nuclear factor-${\kappa}B$ pathway.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.998-1005
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• 1997

Kimchi showed protective effect from oxidative damage generated by hydrogen peroxide and paraquat. To investigate the major components of kimchi which reduce the cytotoxicity against reactive oxygen species, keratinocyte(A431, epidermoid carcinoma, human) and fibroblast(CCD-986SK, normal control, human) were cultured under oxidative stress condition provoked by paraquat, a superoxide anion generator, and hydrogen peroxide in the absence or presence of kimchi ingredients. Most keratinocyte and fibroblast cells were killed by hydrogen peroxide and paraquat over 1mM concentration, but kimchi ingredients showed protective effects from oxidative damage generated by hydrogen peroxide and onion, among those, garlic showed the most remarkable preventive effect. Most of kimchi ingredients showed protective effect against paraquat, especially leek notably increased cell survival. For fibroblast cells, ginger had the preventive effect against paraquat, especially leek notably increased cell survival. For fibroblast cells, ginger had the preventive effect from cell killing by high dose of hydrogen peroxide, but most ingredients were not effective against paraquat.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.303-306
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• 2006

This experiment was investigated the influence of water stress in growth and yields of safflower. The water stress treatment was early growth stage(Mar. 20~Apr. 18), middle growth stage(Apr. 29~May 28) and last growth stage(Jun. 8~Jul. 7) for 30 days, respectively. Stem length of plant was 127 cm in normal irrigation(control) state and that of growth middle stage at drought state was 96 cm, to be shorted more 31 cm than that of normal irrigation state, also other growth rate of plant was decreased, relatively. Number of effective flower bud per $m^2$ was 224 ea in normal irrigation state, 114 ea in growth middle stage at drought state. Yield of seed at drought state decreased 37% and 13% in growth middle stage(222 kg/10a) and last stage(307 kg/10a) than 353 kg/10a in normal irrigation state. According to the result, it could be estimated that optimum irrigation time(0.05 MPa) was 23days after non-rainfall at early growth stage(from sowing seed time to 30 days after sowing seed), 10 days in middle growth stage(41-70 days after sowing seed) and 9 days in last growth stage(81-110 days after sowing seed), to prevent the damage of drought.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.5
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• pp.1303-1310
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• 2005

This study was performed to investigate the effect of Bunsimgieumgagam on the stress due to the maternal separation in rat. In this study, we researched in 'the behavioral observation', 'the changes of body weight', 'quantitative analysis of the number of BrdU-positive cells per section in dentate gyrus of hippocampus', 'free radical scavenging assay' and 'MTT-based cytotoxicity assay of SK-N-SH cell line', in order to figure out the effect on which Bunsimgieumgagam has the increase of neuron in dentate gyrus of hippocampus damaged by the stress due to the maternal separation. In the behavioral Observation, Bunsimgieumgagam was also efficacious against the decline of one's behavior and anorexia derived from the stress by the maternal separation. In the change of body weight, it showed that the Bunsimgieumgagam is effective in the recovery of weight loss caused by heavy stress(p<0.05). Also, Bunsimgieumgagam had an increasing effect, which is similar to a normal state, on DG's neuron in hippocampus (P<0.001). In free radical scavenging assay, Bunsimgieumgagam had a superior free radical scavenging effect. And it showed a significant result with the high cell proliferation effect in MTT-based cytotoxicity assay(P<0.01, p<0.001) This result suggest that Bunsimgieumgagam has an anti-stress effect and a proliferation effect of neuron in dentate gyrus of hippocampus, and it shows the potential of Bunsimgieumgagam in the treatment for the various disorders derived from children's stress.