• 대한지역사회영양학회지
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• 제11권2호
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• pp.279-288
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• 2006

The role of free radicals in the progression of many diseases and aging has been given a great attention and total antioxidant status (TAS) has shown to be reduced with aging. The incidence of hypertension has shown to be relatively high in the aged population, and it is known to be associated with increased obesity and oxidative stress. The aim of this study was to examine the obesity indices and the total antioxidant status in hypertensive elderly (64y$\alpha$-tocopherol, $\beta$-carotene and ascorbic acid did not show their significant correlations with TAS. These results showed that the hypertensive elderly are prone to be obese and to have increased TAS. Due to unknown factors affecting TAS values, measurement of plasma TAS as a sole indicator of total antioxidant capacity is limited to fully understanding changes in the body's free radical trapping power. However, the results from the current study may suggest that hypertension and/or obesity might increase oxidative stress, followed by increased the body's total antioxidant defense system.

• 한국안전학회지
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• 제26권3호
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• pp.83-90
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• 2011

It is well known that urgency resulted from time stress can be a great cause to industrial accidents. Therefore, time stress has been studied in the aspect of macroscopic view, namely industrial safety management, but has not been studied in microscopic view such as psychophysiological approach. Among diverse psychophysiological indices, Electroencephalogram(EEG) would be on of the most objective psychophysiological research technique on human errors though few research has been taken yet. This study aimed to get characteristics of human error while committing a simple arithmetic addition task by utilizing the power spectrum technique of EEG data. Each experiment was composed of 2 tasks under different condition - with and without time stress. As subjects, 5 young undergraduate students in their early twenties participated in this study. The results advocated a well-known fact that time stress downgrades the performance of human workers. However, correct answer rate and response time were not significantly influenced by time stress factor which might be explained by the constructural factor adopted in the present study. As in the previous studies, among various EEG-related measures, relative band power ratios of ${\alpha}$ and ${\beta}$ waves to sum of ${\alpha}$,${\beta}$,${\theta}$ wave powers, namely $P_{{\alpha}/({\alpha}+{\beta}+{\theta})}$ and $P_{{\beta}/({\alpha}+{\beta}+{\theta})}$ seemed to be the most effective measures to grasp variation of brain activities in time-stressed situation so that discussions were expanded about their variations.

• 한국유기농업학회지
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• 제31권4호
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• pp.469-477
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• 2023

Animal welfare has been gradually gathering more attention from consumers over time, making it increasingly important to assess the level of stress experienced by livestock. Traditionally, stress has been measured by collecting blood to assess cortisol levels, an action that can be considered distressing for the animal. Therefore, we aimed to explore the feasibility of using hair as an alternative medium to blood for stress assessment. We utilized B/F (blood collected at the farm), B/A (blood collected after transport to the auction), and H/A (hair collected at the auction after blood sampling) from calves at the age of 7-9 months transported from the farm to the auction. Hair underwent a washing and extraction process to utilize hair extracts, while blood was centrifuged to analyze using ELISA. The cortisol concentration in the blood was significantly higher in B/A compared to B/F (p<0.05), confirming that the calves experienced stress during transportation. Additionally, H/A was significantly lower than both B/A and B/F (p<0.0001). These results emphasized that cortisol in hair is not suitable for investigating short-term stress in livestock, as it is with blood. While measuring stress indices using hair may not be appropriate for replacing blood, it is considered a highly suitable practice for animal welfare, and further research in this area should be continued.

• 한국환경과학회지
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• 제25권7호
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• pp.951-961
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• 2016

To prevent increasing instances of heat-related illnesses due to heat waves generated by climate change, a customized thermal environment index should be developed for outdoor workers. In this study, we conducted sensitivity analysis of the Masan harbor during a heat wave period (August 9th to 15th, 2013) using the MENEX model with metabolic rate and clothing-insulation data, in order to obtain realistic information about the thermal environment. This study shows that accurate input data are essential to gather information for thermophysiological indices (PST, DhR, and OhR). PST is sensitive to clothing insulation as a function of clothing. OhR is more sensitive to clothing insulation during the day and to the metabolic rate at night. From these results, it appears that when exposed to high-temperature thermal environments in summer, wearing highly insulated clothing and getting enough rest (to lower the metabolic rate) can aid in preventing heat-related illnesses. Moreover, in the case of high-intensity harbor work, quantification of allowed working time (OhR) during heat waves is significant for human health sciences.

• 한국전산유체공학회지
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• 제16권4호
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• pp.64-71
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• 2011

Cerebral aneurysm mostly occurs at a bifurcation of the circle of Willis. When the cerebral aneurysm is ruptured, a disease like subarachnoid hemorrhage and stroke is caused and this can be even deadly for patients. Generally it is known that causes of the intracranial aneurysm are a congenital deformity of the artery and pressure or shear stress from the blood flow. A blood flow pattern and the geometry of the blood vessel are important factors for the aneurysm formation. Research for several hemodynamic indices has been performed and these indices can be used for the prediction of aneurysm initiation and rupture. Therefore, the numerical analysis was performed for hemodynamic characteristics of the blood flow through the cerebral artery applying the various bifurcation angle and flow rate ratio. We analyze the flow characteristics using indices from the results of the numerical simulation. In addition, to investigate the flow pattern in the aneurysm according to the bifurcation angle and the flow rate ratio, we performed the numerical simulation on the supposition that the aneurysm occurs.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2011년 춘계학술대회논문집
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• pp.161-168
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• 2011

Cerebral aneurysm mostly occurs at a bifurcation of the circle of Willis. When the cerebral aneurysm is ruptured a disease like subarachnoid hemorrhage and stroke is caused and this can be even deadly for patients. Generally it is known that causes of the intracranial aneurysm are a congenital deformity of the artery and pressure or shear stress from the blood flow. A blood flow pattern and the geometry of the blood vessel are important factors for the aneurysm formation. Research for several hemodynamic indices has been performed and these indices can be used for the prediction of aneurysm initiation and rupture. Therefore, the numerical analysis was performed for hemodynamic characteristics of the blood flow through the cerebral artery applying the various bifurcation angle and flow rate ratio. We analyze the flow characteristics using indices from the results of the numerical simulation. In addition, to investigate the flow pattern in the aneurysm according to the bifurcation angle and the flow rate ratio, we performed the numerical simulation on the supposition that the aneurysm occurs.

• Journal of Electrical Engineering and Technology
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• 제1권4호
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• pp.414-422
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• 2006

Deterministic techniques have been applied in power system planning for many years and there is a growing interest in combining these techniques with probabilistic considerations to assess the increased system stress due to the restructured electricity environment. The overall reliability framework proposed in this paper incorporates the deterministic N-1 criterion in a probabilistic framework, and results in the joint inclusion of both adequacy and security considerations in system planning. The combined framework is achieved using system well-being analysis and traditional adequacy assessment. System well-being analysis is used to quantify the degree of N-1 security and N-1 insecurity in terms of probabilities and frequencies. Traditional adequacy assessment is Incorporated to quantify the magnitude of the severity and consequences associated with system failure. The concepts are illustrated by application to two test systems. The results based on the overall reliability analysis framework indicate that adequacy indices are adversely affected by a generation deficient environment and security indices are adversely affected by a transmission deficient environment. The combined adequacy and security framework presented in this paper can assist system planners to realize the overall benefits associated with system modifications based on the degree of adequacy and security, and therefore facilitate the decision making process.

• 한국환경보건학회지
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• 제22권4호
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• pp.91-101
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• 1996

Exposure indices are important tools which enable scientists to reliably predict and detect exposures to xenobiotics and resultant cell injury. Since the de novo synthesis of stress proteins can be detected early after exposure to some agents, analysis of toxicant-induced changes in gene expression, i.e. alterations in patterns of protein synthesis, may be useful to develop as biomarkers of exposure and toxicity. The acute and chronic effects of cadmium(Cd, $CdCl_2$ 20 mg/kg) on Wistar male rats were evaluated concerning cadmium contents, tissues enzyme activity, HSP expression. The results of the study were as follows: 1. Less cadmium was absorbed through the digestive tracts, but the ratio of contents in renal to hepatic cadmium was higher at 8 weeks after treatment. 2. ALT(alanine aminotransferase), AST(aspartate aminotransferase), glucose, BUN(blood urea nitrogen), creatinine, the key indices of the clinical changes in hepatic and renal function were significantly changed by the cadmium treatment after 1 week in liver, after 4 weeks in kidney. 3. Enhanced synthesis of 70 KDa relative molecular mass proteins were detected in 2 hours after cadmium exposure, with maximum activity occurring at 8~48 hours. Induction of $HSP_{70}$ was evident at proximal tubules and glomeruli in kidney. Testicular cells produced enough HSP to be detected normally. From the above results, it could be concluded that $HSP_{70}$ induction by the cadmium treatment was a rapid reaction to indicate the exposure of xenobiotics.

• 한국산학기술학회논문지
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• 제11권6호
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• pp.2169-2177
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• 2010

본 연구는 공무원들의 스트레스나 피로수준과 같은 사회심리적 건강상태가 그들의 직급, 근무경력 등의 직업관련 특성이나 업무요구도, 업무자율성, 직장 내에서의 사회적 지지와 같은 직무스트레스 내용에 의해 영향을 받고 있는지를 구조방정식모형을 통하여 검토하고자 시도하였다. 연구대상은 대전광역시의 5개 정부 공공기관에 근무하는 일반 사무직 행정공무원 805명이었으며, 자료 수집은 2009년 10월 1일부터 11월 30일까지의 기간 동안에 표준화된 자기기입식 설문지(self-administered questionnaire)를 사용하여 실시하였다. 연구결과, 공무원들의 스트레스 및 피로수준은 직급, 근무경력, 업무만족도, 업무자율성, 상사의 지지도 및 동료의 지지도와는 유의한 음의 상관관계를 나타낸 반면, 년 간 결근일수, 업무요구도와는 유의한 양의 상관관계를 나타내었다. 구조방정식모형 분석 결과 연구대상자들의 직무스트레스 요인은 직업관련 특성 요인보다 사회심리적 건강상태에 더 큰 영향을 미쳤으며, 직무스트레스가 높을수록 사회심리적 건강상태를 나타내는 스트레스와 피로수준을 높여주는 것으로 나타났다. 한편, 직업관련 특성의 인지정도가 높을수록 직무스트레스 요인을 감소시키는 효과가 있는 것으로 나타났다. 따라서 공무원들의 스트레스나 피로를 감소시키기기 위해서는 직업관련 특성에 따른 직무내용의 개선을 위한 프로그램의 개발 및 시행이 필요할 것으로 생각된다.

• 종양간호연구
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• 제2권1호
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• pp.5-16
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• 2002

Purpose: This study was to develop a stress-adaptation model for family caregivers of cancer patients that could provide the basis of planning nursing intervention. Method: A hypothetical model was developed using the family adaptation model proposed by Haley et al. (1987). In the literature, the stressor was identified as patient's characteristics, caregiver's characteristics, duration of illness, and family life events. It affected stress appraisal, family resources, family coping and finally caregiver's adaptation. In this model, 18 paths were constructed. Data were collected from 241 caregivers, whose family members were in treatment between June and August 2000, at 3 university hospitals and were analyzed by SPSS and LISREL programs. Results: 1) The overall fitness indices of the hypothetical model were x 2=267.78 (P= .0), GFI= .92, AGFI= .87, NFI= .93, NNFI= .93, PNFI= .64, PGFI= .55, and RMR= .43. Ten of the eighteen paths proved to be significant. 2) To improve the model fitness, the hypothetical model was modified considering modification indices and the paths proved not significant. Final model excluded 3 paths demonstrated to be improved by x2=161.96 (P= .00), GFI= .95, AGFI= .91, NFI= .96, NNFI= .96, and RMR= .23. Twelve of fifteen paths proved to be significant. 3) Stress appraisal was influenced by disease related characteristics and duration of illness and was explained 22% of the variance. Family resources were influenced by stress appraisal and was explained 57% of variance. Family coping was influenced by disease related characteristics, caregiver's characteristics, duration of illness, family life event, and stress appraisal and was explained 57% of variance. Family caregiver adaptation was influenced by disease related characteristics, caregiver's characteristics, stress appraisal, and family coping and was explained 31% of variance. Twelve of fifteen paths were significant. Conclusion: Based on this study, to help family caregivers to adapt, individual intervention is necessary with consideration of disease related and caregiver's characteristics and duration of illness. The intervention should include efforts to raise the family resources and to identify positively the stress they encounter, and there is a need to establish an adaptation model that considers emotional aspects of family caregivers. Since there is a difference in emotional status depending on the disease stage, a study needs to be done to analyze the differences among the disease stages (diagnosis, treatment, recurrence, and terminal stages).