• 한국물환경학회지
• /
• 제28권2호
• /
• pp.213-218
• /
• 2012

Abnormal dissolved oxygen concentration in aquatic habitat, both depletion and supersaturation, can be stress factor to aquatic animals. In this study the nationwide distribution of oxygen supersaturation was analyzed for three categories of streams (43 urban streams, 15 rural streams, and 14 forest streams) by using monitoring network data of the Korean Ministry of Environment. From the distribution analysis 30% of urban streams showed hyperoxic condition of eutrophic level, while no forest stream showed hyperoxic condition. The physiological effect of hyperoxia on fish was examined using two species of fish Zacco koreanus, which resulted in higher concentration of a stress hormone (cortisol) in fish exposed to hyperoxic concentration (196%) of oxygen. This study shows that hyperoxic condition is ubiquitous in urban and rural Korean streams, and it can be a stress factor to aquatic animals.

• 한국간호교육학회지
• /
• 제21권1호
• /
• pp.28-35
• /
• 2015

Purpose: The purpose of this study was to examine the effects of prior information about ICU environment on the anxiety and environmental stress of cardiac surgery ICU patients. Methods: A non-equivalent control group non-synchronized quasi-experimental research design was used. Participants were 60 (control 30, experimental 30) patients who had been admitted to ICU. Prior information about the ICU environment was provided to the experimental group. The anxiety level of subjects was measured by State-Trait Anxiety Inventory (STAI) and the stress level of subjects was measured by the Intensive Care Unit Environmental Stressor Scale (ICUESS). Data were analyzed using a Chi-square test or a Fisher's exact test, independent samples t-test, and paired samples t-test. Results: There was no difference in Anxiety (t=-0.58, p=.563), but there was a significant difference in environmental stress (t=10.46, p<.001). Conclusion: Providing prior information would be an effective nursing intervention to reduce environmental stress.

• 한국토양비료학회지
• /
• 제49권4호
• /
• pp.355-367
• /
• 2016

Soil salinization refers to the buildup of salts in soil to a level toxic to plants. The major factors that contribute to soil salinity are the quality, the amount and the type of irrigation water used. The presented review discusses the different sources and causes of soil salinity. The effect of soil salinity on biological processes of plants is also discussed in detail. This is followed by a debate on the influence of salt on the nutrient uptake and growth of plants. Salinity decreases the soil osmotic potential and hinders water uptake by the plants. Soil salinity affects the plants K uptake, which plays a critical role in plant metabolism due to the high concentration of soluble sodium ($Na^+$) ions. Visual symptoms that appear in the plants as a result of salinity include stunted plant growth, marginal leaf necrosis and fruit distortions. Different strategies to ameliorate salt stress globally include breeding of salt tolerant cultivars, irrigation to leach excessive salt to improve soil physical and chemical properties. As part of an ecofriendly means to alleviate salt stress and an increasing considerable attention on this area, the review then focuses on the different plant growth promoting bacteria (PGPB) mediated mechanisms with a special emphasis on ACC deaminase producing bacteria. The various strategies adopted by PGPB to alleviate various stresses in plants include the production of different osmolytes, stress related phytohormones and production of molecules related to stress signaling such as bacterial 1-aminocyclopropane-1-carboxylate (ACC) derivatives. The use of PGPB with ACC deaminase producing trait could be effective in promoting plant growth in agricultural areas affected by different stresses including salt stress. Finally, the review ends with a discussion on the various PGPB activities and the potentiality of facultative halophilic/halotolerant PGPB in alleviating salt stress.

• Smart Structures and Systems
• /
• 제12권3_4호
• /
• pp.465-482
• /
• 2013

Recently, a novel stress sensor, which utilizes the elasto-magnetic (EM) effect of ferromagnetic materials, has been developed to measure stress in steel cables and wires. In this study, the effectiveness of this EM based stress sensors for monitoring of the cable tension force of a real scale cable-stayed bridge was investigated. Two EM stress sensors were installed on two selected multi-strand cables in Hwa-Myung Bridge, Busan, South Korea. Conventional lift-off test was conducted to obtain reference cable tension forces of two test cables. The reference forces were used to calibrate and validate cable tension force measurements from the EM sensors. Tension force variations of two test cables during the second tensioning work on Hwa-Myung Bridge were monitored using the EM sensors. Numerical simulations were conducted to compare and verify the monitoring results. Based on the results, the effectiveness of EM sensors for accurate field monitoring of the cable tension force of cable-stayed bridge is discussed.

• 한국식물생명공학회:학술대회논문집
• /
• 한국식물생명공학회 2005년도 추계학술대회 및 한일 식물생명공학 심포지엄
• /
• pp.167-167
• /
• 2005

• 한국생명과학회:학술대회논문집
• /
• 한국생명과학회 2005년도 국제학술심포지움 The 44th Annual Meeting of Korean Society for Life Science
• /
• pp.204-204
• /
• 2005

• 한국도로학회논문집
• /
• 제14권5호
• /
• pp.31-45
• /
• 2012

PURPOSES: In Korea, rapid maintenance of distressed concrete pavement is required to prevent traffic jam of the highway. Asphalt concrete overlay has been used as a general maintenance method of construction for aged concrete pavement. AC overlay on existing concrete pavements experience various early distresses such as reflection crack, pothole and rutting, due to different physical characteristics between asphalt overlay and existing concrete pavement. Bonded concrete overlay(BCO) is a good alternative since it has advantages that can reduce various distresses during the service life since overlay material has similar properties with existing concrete pavements. Recently, BCO which uses the ultra rapid harding cement has been applied for maintenance of highway. BCO has advantage of structural performance since it does monolithic behave with existing pavement. Therefore, it is important to have a suitable bond strength criteria for securing performance of BCO. Bond strength criteria should be larger than normal tensile stress and horizontal shear stress occurred by traffic and environmental loading at bond interface. Normal tensile stress and horizontal shear stress need to estimated for the establishment of practical bond strength criteria. METHODS: This study aimed to estimate the bond stresses at the interface of BCO using the three dimensional finite element analysis. RESULTS: As a result of this study, major failure mode and maximum bond stress are evaluated through the analysis of normal tensile stress and horizontal shear stress for various traffic and environmental load conditions. CONCLUSIONS: It was known that normal tensile stresses are dominated by environmental loading, and, horizontal shear stresses are dominated by traffic loading. In addition, bond failure occurred by both of normal tensile stresses and horizontal shear stresses; however, normal tensile stresses are predominated over horizontal shear stresses.

• BMB Reports
• /
• 제41권3호
• /
• pp.259-265
• /
• 2008

Three peroxidase (POD) cDNAs were isolated from dehydration-treated fibrous roots of sweetpotato (Ipomoea batatas) plant via the screening of a cDNA library, and their expressions were assessed to characterize functions of each POD in relation to environmental stress. Three PODs were divided into two groups, designated the basic PODs (swpb4, swpb5) and the anionic PODs (swpa7), on the basis of the pI values of mature proteins. Fluorescence microscope analysis indicated that three PODs are secreted into the extracellular space. RT-PCR analysis revealed that POD genes have diverse expression patterns in a variety of plant tissues. Swpb4 was abundantly expressed in stem tissues, whereas the expression levels of swpb5 and swpa7 transcripts were high in fibrous and thick pigmented roots. Swpb4 and swpa7 showed abundant expression levels in suspension cultured cells. Three POD genes responded differently in the leaf and fibrous roots in response to a variety of stresses including dehydration, temperature stress, stress-associated chemicals, and pathogenic bacteria.

• 한국환경독성학회:학술대회논문집
• /
• 한국환경독성학회 2006년도 춘계학술대회 논문집
• /
• pp.89-90
• /
• 2006

• 보건교육건강증진학회지
• /
• 제24권3호
• /
• pp.61-71
• /
• 2007

Objectives: The research was conducted to evaluate the socio-demographic, life style and work related factors of stress and fatigue, and correlation between them in the white collar workers. Methods: This study was targeted on white collar workers of medium-sized company in Kimhae city including 249 people; 167 of males, 82 of females. The data was collected by structured questionnaires and analyzed using t-test, ANOVA, Pearson correlation and stepwise multiple regression with SPSS 12.0. Result: Both stress and fatigue levels were higher for female of gender, 20s of age, single of marital status in socio-demographic factors. The stress level was higher for current smokers and lower frequency of regular exercise per week, and both stress and fatigue levels were higher for unsatisfied sleeping in lifestyle factors. The stress level was lower for 5-day workweek system and experience of downsizing, and both stress and fatigue levels were higher far lower period of employment in work related factors. The correlation coefficient(r) between stress and fatigue level was 0.578, which was highly statistically significant. According to stepwise multiple regression analysis, factors affecting stress were unsatisfied sleeping, female and lower frequency of regular exercise per week, and those affecting fatigue were younger age and unsatisfied sleeping. Conclusion: This study provided strong support for associations between stress and fatigue, and we suggest that modifiable factors such as regular exercise and satisfied sleeping would be important for white collar workers to reduce their stress and fatigue.