• 감성과학
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• 제4권2호
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• pp.33-38
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• 2001

본 연구는 가상현실을 이용하여 교통사고 후 경험하게 되는 불안감 및 공포감과 같은 심리적인 후유장애에 대한 치료 프로그램을 개발하기 위한 예비연구로 수행되었다. 가상현실을 통한 교통사고 후유장애 프로그램의 핵심내용이 되는 운전주행 시나리오의 효과를 검증하고, 이완훈련 등의 불안감소 훈련의 효과를 피험자를 통해 검증해 보았다. 총 8명의 피험자(정상인 7명, 교통사고 환자 1명)를 대상으로 세 가지 주행상황 시나리오를 제시하고, 이후 이완훈련을 실시하였다. 그 결과 이완훈련 후 유의미한 불안감소 효과가 나타났다. 하지만 각각의 주행상황에 따라서 불안이 증가되는 경향성은 나타났으나 통계적으로 유의미한 수준에 이르지는 못하였다. 이를 종합하여 볼 때, 주로 정상인을 대상으로 한 연구임에도 불안유발 경향성이 나타난 점은 고무적이나 교통사고자를 대상으로 한 경험적인 증명이 필요하며, 가상현실을 이용한 이완훈련은 효과적인 것으로 판명되었다.

• 유변학
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• 제11권2호
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• pp.82-90
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• 1999

전기유변 유체(electorheological fluid)는 전기장이 가해지면 아주 짧은 시간에 유변 물성이 급격히 변하며 그 응답이 반복적으로 수행될 수 있는 유체이다. 전기유변 유체는 전기장의 세기에 따라 면찰 응력(shear stress)과 점도의 크기를 조절할 수 있고, 짧은 응답시간은 빠른 제어를 요하는 분야에 효과적으로 이용될 수 있지만, 낮은 항복 응력, 조업 온도 범위의 제한성, 전력 소비에 의한 열적 불안정성, 그 외에도 응집, 침전 등의 단점이 있다. 특히, 이 유체가 갖는 항복 응력의 크기와 그 성질은 실제 장치에 응용하는데 중요한 특성이다. 이러한 문제점을 해결하기 위해 면찰 유동(shear flow)이 아닌 압착 유동(squeezing flow)을 고려하게 되었고, 이 유동 하에서의 전기유변 유체의 거동을 이해하기 위해 본 연구에서는 전기유변 유체의 압착 유동에 대한 동적 수치모사를 수행하였다. 고립된 사슬 구조에 대한 수치모사를 통하여 사슬의 위치와 압착 속도를 변화 시키면서 이에 따른 수력학적 힘과 정전기적 힘의 효과를 예측하였으며, 이를 토대로 많은 사슬을 포함한 현탁액 모델에 대한 수치모사를 수행하였다. 그 결과 실험에서 관찰할 수 있는 수직 응력의 증가와 초기 항복 응력의 존재를 확인하였고, 수직 응력의 효과적인 제어는 수력학적 힘과 정전기적 힘 간의 최적화된 조건에서 얻어질 수 있음을 예측하였다. 이러한 수치모사의 개발을 통해 압착 유동을 이용한 전기유변 유체의 응용에 대한 이론적인 토대를 마련하였고, 향후 보다 깊은 이해를 위한 기반을 구축할 수 있었다.

• 대한통합의학회지
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• 제6권3호
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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.

• 여성건강간호학회지
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• 제18권3호
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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.

• 한국학교보건학회지
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• 제20권2호
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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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• 제28권5호
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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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• 제26권3_4호
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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.

• 한국식품영양과학회지
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• 제26권6호
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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.

• 한국토양비료학회지
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• 제39권5호
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• pp.303-306
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• 2006

홍화 생육중 한발이 생육과 수량에 미치는 영향을 구명하기 위해 시험을 수행한 결과는 다음과 같다. 경장은 정상 관수구가 127 cm인데 비해 토양 수분장력이 5월초부터 증가하기 시작해 0.5 MPa까지 도달한 생육 중기 단수시는 96 cm로서 31 cm적었으며 경태, 엽수, 분지수 등의 생육도 생육 중기 단수시가 가장 저조하였다. $m^2$당 유효 화두수는 정상 관수구가 244개인데 비해 생육 중기 단수시는 144개로 매우 적었다. 종실 수량은 정상 관수구가 10a 당 353 kg인데 비해 생육 중기 단수시는 222 kg, 토양 수분 장력이 0.54 MPa까지 도달한 생육 후기 단수시는 307 kg으로서 각각 37%, 13% 감소되었다. 홍화 생육중 한발에 따른 피해를 방지하기 위한 적정 관수 시기(0.05 MPa)는 생육 초기(파종시~파종후 30일)는 무강우 후 23일, 생육 중기(파종후 41~70일)는 10일, 생육후기(파종후 81~110일)는 9일로 예측되었으나, 이 결과는 당년의 기상에만 국한된다는 것을 염두에 두어야 한다. 위와 같은 결과에 대한 일반화는 축적된 기상 자료와 증발산량 자료 등에 대한 해석이 있은 추후 연구가 필요하다.

• 동의생리병리학회지
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• 제19권5호
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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.