• 대한의용생체공학회:의공학회지
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• 제18권2호
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• pp.179-186
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• 1997

Steady and physiological flows of a Newtonian fluid and blood in the abdominal gorta/iliac artery bifurcation are numerically simulated to understand the etiology and pathogenesis of atherosclerosis. Distributions of velocity, pressure, and wall shear stress in the bifurcated arterial vessel model are calculated to investigate the differences of flow characteristics between steady and physiological flows and to compare flow characteristics of blood with that of a Newtonian fluid For the given Reynolds number the flow characteristics of physiological flows for a Newtonian fluid and blood in the bifurcated arterial vessel are quite different from thcse of steady flows. No flow separation or flow reversal in the bifurcated region appears downstream of a stenosis during the acceleration phase. However, during the deceleration phase the flow exhibits flow separation in the outer walls of daugtlter branches, which extends to the entire wall region.

• 대한인간공학회지
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• 제26권1호
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• pp.11-18
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• 2007

The physiological and biochemical responses of healthy men and women to life stress were measured in order to temperature, blood pressure (BP), heart rate (HR) and galvanic skin response (GSR) were selected as physiological stress indices and salivary cortisol level was used as a biochemical stres biomarker. Twenty six (male 14 and female 13) colege students were participated in the experiment. Female showed the significant higher value of salivary cortisol level (p<0.01), diastolic BP (p<0.01), and HR (p<0.01) than male. The difference of skin temperature between forehead and fingertip correlated significantly with salivary cortisol level (p<0.01). The LF(low frequency)/HF(high frequency) ratio of HRV also correlated significantly with salivary cortisol level (p<0.01). However, BP, HR and GSR corelated insignificantly with salivary cortisol level. We suggest that LF/HF ratio of HRV and skin temperature may be good indices for the assessment of life stress, and may apply to measure the stress level of individual in real time.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.196-196
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• 2017

Oilseed crop Camelina (Camelina sativa L.) is a suitable for biodiesel production that has high adaptability under low-nutrient condition like marginal land and requires low-input cost for cultivation. Enhanced abiotic stress tolerance of Camelina is very important for oil production under the wide range of different climate. CsRCI2s (Rare Cold Inducible 2) are related proteins in various abiotic stresses that predicted to localized at plasma membrane (PM) and endoplasmic reticulum (ER). These proteins are consist of eight-family that can be divided into tail (CsRCI2D/E/F/G) and no-tail (CsRCI2A/B/E/H) type of C-terminal. However, it is still less understood the function of C-terminal tail. In this study, CsRCI2D/H genes were cloned through gateway cloning system that used pCB302-3 as destination vector. And we used agrobacterium-mediated transformation system for generation of overexpression (OX) transformants. Overexpression of target gene was confirmed using RT-PCR and segregation ratio on selection media. We analyzed physiological response in media and soil under abiotic stresses using CsRCI2D and CsRCI2H overexpression plant. To compare abiotic stresses tolerance, wild type and CsRCI2D/H OX line seeds were sown on agar plate treated with various NaCl and mannitol concentration for 7 days. In the test of growth rate under abiotic stress on media, CsRCI2H OX line showed similar to NaCl and mannitol stress. In the other hand, CsRCI2D OX line showed to be improved stress tolerance that especially increased in 200mM NaCl but was similar on mannitol media. In greenhouse, WT and CsRCI2D/H OX lines for physiological analysis and productivity under abiotic stresses were treated 100, 150, 200mM NaCl. Then it was measured various parameters such as leaf width and length, plant height, total seed weight, flower number, seed number. CsRCI2H OX line in greenhouse did not show any changes in physiological parameters but CsRCI2D OX line was improved both physiological response and productivity under NaCl stress. Among physiological parameters of CsRCI2D OX line under NaCl stress, leaf length and width were observed shorter than WT but it were slightly longer than WT in 200mM NaCl stress. Furthermore, total seed weight of CsRCI2D OX line under stress displayed to decrease than WT in normal condition, but it was gradually raised with increasing NaCl stress then more than WT relatively. These results suggested CsRCI2D might be contribute to improve abiotic stress tolerance. However, function of CsRCI2H is need to more detail study. In conclusion, overexpression of CsRCI2s family can generate various environmental stress tolerance plant and may improve crop productivity for bio-energy production.

• 한국해양생명과학회지
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• 제3권2호
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• pp.87-95
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• 2018

To investigate effects of starvation on physiological changes, stress response, and survival of cobitid loach (Misgurnus anguillicaudatus) exposed to sodium nitrite (NaNO₂), a 4-week experiment was conducted. Fewer fish survived in the starved group than those in the fed group during the experiment. Starvation resulted in growth retardation, leading to differences in body length and body depth between fed and starved groups. The fed gorup continued to grow and remained in good condition. Blood chemical analysis (plasma cortisol and glucose) showed significant differences in stress response to nitrite exposure between fed and starved groups (p < 0.05). These results suggest that all parameters employed in this study to assess effects of starvation with NaNO₂ stress are useful information for researching nutritional status in cobitid loach.

• 한국보육지원학회지
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• 제18권6호
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• pp.75-99
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• 2022

Objective: This study aims to explore ways to empirically analyze and manage childcare teachers' job stress based on their relationship with stress-related physiological indicators measured by a fitness tracker. Methods: The study participants were 27 childcare teachers in Gyeonggi-do and wore Garmin's wearable fitness tracker Vivosmart 4 for 15 days for three months. The collected information was analyzed for mean, SD, ANOVA, and correlation using JAMOVI 2.00. Results: First, among the daily changes of physiological indicators measured by a fitness tracker, the data collected on Mondays were significant. On Mondays, the stress index was high, the duration of the rest period was short, and the sleep time was short. The stress of childcare teachers showed a significant negative relationship with the body battery which was calculated by considering the duration of the rest period, heart rate variability, stress, and activity level. Also, the duration of deep sleep was positively correlated with a low degree of stress. There was a significant relationship between the childcare teachers' psychological indicators and the biomarkers measured by fitness trackers. Conclusion/Implications: Stress research using a fitness tracker is big data, and in-depth analysis is possible. Fitness trackers can collect and utilize repeated measurement data for each individual childcare teacher.

• Perspectives in Nursing Science
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• 제2권1호
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• pp.61-75
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• 2005

Physical and psychological events can produce stress response in various degrees. Stress affects many aspects of physiology including both brain and peripheral elements which is represented as hypothalamus-pituitary-adrenal axis. Brain elements consist of corticotropin-releasing hormone(CRH), locus ceruleus(LC)-norepinephrine(NE)/autonomic system. Peripheral elements include pituitary-adrenal axis and the autonomic nervous system, which coordinate the stress response. Current trend of the stress researches is emphasizing the mechanisms of the stress response which is adaptive or become maladaptive. This review introduces 1) the concepts of stress, 2) physiological and behavioral aspects of stress responses, 3) the consequences of stress response, 4) the measurements of stress and 5) stress management for those interested in stress research.

• Journal of Korean Biological Nursing Science
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• 제17권3호
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• pp.219-227
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• 2015

Purpose: This study was conducted to review physiological mechanisms of internet addiction and to construct a theoretical framework for cognitive behavioral therapy for internet addicts. Methods: We searched for relevant literature in the PubMed and RISS databases using the terms "internet addiction", "internet game addiction", "internet abuser", and "online game". Only English, full-text articles published from 2000 to 2015 were included in this review of physiological indicators of internet addiction. Finally, 12 articles were selected for review. Results: The theoretical framework developed based on the review proposes that excessive internet use itself may induce physiological stress responses with an increase of stress-related hormones and neurotransmitters. Prolonged abnormal responses of these physiological features produce negative structural and functional changes in the prefrontal cortex, which is mainly involved in cognitive and executive functions. These changes may result in decreased cognitive function. As a stressor, excessive internet use leads to transforming voluntary use into involuntary, habitual use and thus promotes the development of internet addiction. Conclusion: The proposed theoretical framework encompasses cognitive processes that may contribute to the effects of internet use-induced physiological stress on internet addiction. We believe that this framework has important implications for developing cognitive behavioral strategies for internet addicts.

• Journal of Mechanical Science and Technology
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• 제17권2호
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• pp.296-309
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• 2003

The periodicity of the physiological flow has been the major interest of analytic research in this field up to now Among the mechanical forces stimulating the biochemical reaction of endothelial cells on the wall, the wall shear stresses show the strongest effect to the biochemical product. The objective of present study is to find the effects of velocity waveform on the wall shear stresses and pressure distribution along the artery and to present some correlation of the velocity waveform with the clinical observations. In order to investigate the complex flow phenomena in the bifurcated tube, constitutive equations, which are suitable to describe the rheological properties of the non-Newtonian fluids, are determined, and pulsatile momemtum equations are solved by the finite volume prediction. The results show that pressure and wall shear stresses are related to the velocity waveform of the physiological flow and the blood viscosity. And the variational tendency of the wall shear stresses along the flow direction is very similar to the applied sinusoidal and physiological velocity waveforms, but the stress values are quite different depending on the local region. Under the sinusoidal velocity waveform, a Newtonian fluid and blood show big differences in velocity. pressure, and wall shear stress as a function of time, but the differences under the physiological velocity waveform are negligibly small.

• 한국정보통신학회논문지
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• 제12권10호
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• pp.1717-1722
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• 2008

스트레스 정도를 측정하기 위한 다양한 도구들이 많이 사용되고 있다. 스트레스 측정에는 심리측정과 생체측정이 있다. 어느 한쪽만을 고려하였을 경우 주관적이거나 객관적 결여가 발생한다. 그 문제점을 보완하기 위해 두 측정을 혼합한 새로운 스트레스 지수가 필요하다. 개인적 특성에 따라 측정 결과도 다양하게 나타나지만, 현재 사용되고 있는 측정도구를 바탕으로 한 일반적인 경우를 고려하여 연구하였다. 심리와 생체 측정 도구를 통해서 얻어지는 지수를 이용하여 통합적인 스트레스 지수를 얻는다. 그래서 임의로 4가지의 스트레스 측정도구를 사용한다. 각 측정도구에서 나온 결과에 대한 멀티지수가 나타나는데, 그 지수들을 각각 좌표평면에 나타내어 스트레스에 대한 균형성과 편향성을 분석하고 진단한다.

• 대한의용생체공학회:의공학회지
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• 제24권5호
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• pp.465-471
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• 2003

본 논문에서는 생체신호 파라미터들을 이용해서 만성적인 스트레스를 평가하는 방법을 개발하고자 하였다. Wistar 쥐에게 14 일간의 소음 스트레스를 부과하고, 매 시간마다 생체신호를 획득하였다. 생체신호로부터 추출한 파라미터들을 통합하기 위한 퍼지추론시스템을 구축하기 위하여, 적응형 뉴로-퍼지 추론시스템으로 퍼지추론시스템의 파라미터들을 구하였다. 훈련 데이터 집합 중 입력 데이터 집합은 생체신호로부터 추출한 파라미터들을, 출력 데이터 집합은 코티솔 호르몬의 생성량으로부터 추정한 목표값을 사용하였다. 퍼지추론시스템으로 생체신호 파라미터들을 통합하고, 그 결과를 24 시간마다 구분하여 Cosinor 분석법을 적용하여 생체리듬의 변화를 관찰하였다. 생체리듬이 깨어진 정도에 의해서 만성적인 스트레스를 평가하였다. 생체신호 파라미터들을 퍼지추론으로 통합하고, 그 결과에서 생체리듬을 분석하여 스트레스 정도를 계산했다. 휴식기의 스트레스 정도를 l이라고 가정하면, 소음 스트레스를 받은지 14일째 되는 날에는 1.37. 7일간의 회복 후에는 1.47의 스트레스 정도가 나왔다. 즉, 쥐는 14일간의 소음으로 휴식 때보다 37% 증가된 스트레스를 받았고, 7일의 회복기를 통해 스트레스로부터 회복되지 않았다.