• The Plant Pathology Journal
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• v.28 no.1
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• pp.101-106
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• 2012

Trifloxystrobin is a strobilurin fungicide, which possesses broad spectrum control against fungal plant diseases. We demonstrated that pre-treating red pepper plants with trifloxystrobin resulted in increased plant growth and leaf chlorophyll content compared with those in control plants. Relative water content of the leaves and the survival rate of intact plants indicated that plants acquired systemic tolerance to drought stress following trifloxystrobin pre-treatment. The recovery rate by rehydration in the drought treated plant was better in those pre-treated with trifloxystrobin than that in water treated plants. Induced drought tolerance activity by trifloxystrobin was sustained for 25 days after initial application. The trifloxystrobin treated red pepper plants also had induced systemic tolerance to other abiotic stresses, such as frost, cold, and high temperature stresses. These findings suggest that applying the chemical fungicide trifloxystrobin induced systemic tolerance to certain abiotic stresses in red pepper plants.

• Korean Journal of Environmental Agriculture
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• v.39 no.3
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• pp.273-279
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• 2020

BACKGROUND: After transplanting, the recent abnormal low temperature caused physiological disorders of pepper seedlings. This study was conducted to evaluate the effects of UV-A LED, a physical elicitor, on the chilling tolerance of pepper seedlings. METHODS AND RESULTS: Seedlings were continuously irradiated with 370 and 385 nm UV-A LEDs with 30 W·m^-2 for 6 d. After that, seedlings were exposed to 4℃ for 6 h and then recovered under the normal growing condition for 2 d. There were no significant differences in growth characteristics of UV-A treatments compared to the control. Fv/Fm values of two UV-A treatments were below 0.8. Electrolyte leakage in the control was increased by chilling stress, while 385 nm UV-A had the significantly lowest value. Total phenolic content and antioxidant capacity of two UV-A treatments significantly increased due to UV-A radiation. However, total phenolic content and antioxidant capacity of the control increased due to chilling stress and tended to decrease again during the recovery time. CONCLUSION: We confirmed that UV-A light was effective to induce the chilling tolerance of pepper seedling, and the supplemental radiation of 385 nm UV-A LED before transplanting could be used as a cultivation technique to produce high quality pepper seedlings.

• Korean Journal of Occupational Health Nursing
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• v.28 no.3
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• pp.156-165
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• 2019

Purpose: The purpose of this study was to compare working condition and health status between parcel delivery workers (PDW) and food delivery workers (FDW) and to examine the factors influencing their health status. Methods: This was a secondary analysis of data collected from the fifth Korean Working Conditions Survey (KWCS). Based on existing literature, a set of variables was chosen from the KWCS. Results: The proportion of PDW who carryied/moved heavy loads and experienced high job stress and lack of rest time was significantly higher than that of FDW. However, more FDW than their counterparts worked atypical hours. The differences in fatigue and well-being between PDW and FDW were not statistically significant. The multiple logistic regression analysis revealed low temperature, tobacco smoke, standing for long periods, and job stress were significant predictors of fatigue or well-being of FDW. Among PDW, noise, tobacco smoke, sitting for long periods, quantitative demands, hiding emotions, support from colleagues, job stress, no recovery period, and night work were significant predictors of fatigue or well-being. Conclusion: The findings of this study may be useful in developing nursing interventions for disease protection health promotion of delivery workers.

• Journal of People, Plants, and Environment
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• v.24 no.6
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• pp.693-705
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• 2021

Background and objective: This study was conducted to investigate the effects of forest therapy programs on reducing post-traumatic stress disorder (PTSD), depression and improving mood states in fire officers. Methods: To determine PTSD, depression, and mood states before and after the forest therapy program, the survey results of 185 fire officers were analyzed. Frequency analysis was conducted to identify the demographic characteristics of the participants, and Wilcoxon signed-rank test to analyze the differences among group. Results: As a result of a comparative analysis of PTSD before and after the program, there was a significant decrease in PTSD from 10.65 ± 12.00 to 5.64 ± 8.29 after the program. Depression also showed a statistically significant difference from 3.21 ± 4.00 to 2.21 ± 3.47 after the program. As a result of comparatively analyzing mood states before and after the program, there was an increase in positive factors and a decrease in negative factors. Total mood disturbance (TMD) also showed a statistically significant decrease from 5.78 ± 17.37 to -7.38 ± 10.35 after the program. Conclusion: This study has significance in verifying that forest therapy programs can bring psychological changes to fire officers, and these results can be used as a basis for stress management and relief of fire officers.

• Korean Journal of Health Education and Promotion
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• v.24 no.3
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• pp.21-34
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• 2007

Objectives: This study aims to examined whether physical activity prevent the negative effect of psychological stress on cardiovascular reactivity by reducing stress induced sympathetic output and preventing norepinephrine depletion negative psych-affective responses. It is assumed that physical activity reduces the magnitude of cardiovascular responses and psychological responses to stress which threaten individuals' physical and mental health. The result of investigating the effect of physical activity on reducing negative physiological and psychological responses would suggest useful information health for practitioners who want to prevent stress-induced diseases, especially coronary heart disease. Methods: participants of this study were 30 students (10 males & 20 females), whose mean age was 21.30 (SD=2.29). Fifteen students (5 males & 10 females) were assigned for in each group, treatment and control groups. They were interviewed and given a survey that included a consent form, demographics sheet and psychological tests, such as State-Trait Anger Expression Inventory and State-Trait Anxiety Inventory. Before the application of psychological stress, participants in treatment group were going through with a course of physical exercise, running on treadmill 15minutes, while participants in control group were not physically active. After exercise, there was 15 minutes resting period before applying cognitive stress. During the experiment, all participants performed challenging cognitive tasks for 20minutes in situations that were designed to experience learned helplessness and measured their cardiovascular reactivity including blood pressure and heart rate every 5 minutes, until 10 minutes after finishing the application of psychological stress(recovering state). In the end of experiment, they were given some psychological test again. Results: Heart rates of exercise group were significantly higher than non-exercise group, especially, five minute after applying cognitive stress and at the end of recovery, in other word 10 minutes after stressful event. Systolic blood pressures of exercise group were lower than those of non-exercise group during the stressful event, but this differences in borderline level of significance. state anger level of exercise group decreased even experiencing stress, while those of non-exercise group increase. And state anxiety level of exercise group decreased in borderline level of significance. Conclusion: This study reiterate health benefits of physical activity and suggest that regular moderate exercise may regulate cardiovascular reactivity and psycho-affective responses from stress by reducing stress induced sympathetic output.

• Science of Emotion and Sensibility
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• v.21 no.1
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• pp.71-82
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• 2018

Stress involves changes in behavior, autonomic function and the secretion of hormones. Autonomic nervous system (ANS) contributes to physiological adaptive process in short durations. In particular, heart rate variability (HRV) analysis is commonly used as a quantitative marker depicting the ANS activity related to mental stress. The aim of this study is to investigate correlations between psychological responses to stress and HRV indices induced by the cognitive stressor. Thirty-three participants rated their mental and physical symptoms occurred during the past two weeks on Stress Response Inventory (SRI), which is composed of seven stress factors that may influence the status of mental stress levels. Then, they underwent the psychophysiological procedures, which are collected electrocardiogram (ECG) signals during a cognitive stress task. HRV indices, the standard deviation of R-R interval (SDNN), root mean square of successive R-R interval difference (RMSSD) and low frequency (LF)/high frequency (HF) ratio were extracted from ECG signals. Physiological responses were calculated stress responses by subtracting mean of the baseline from the mean of recovery. Stress factors such as tension, aggression, depression, fatigue, and frustration were positively correlated to HRV indices. In particular, aggression had significant positive correlations to SDNN, RMSSD and LF/HF ratio. Increased aggressive responses to stress correlated with the increases of all HRV indices. This means the increased autonomic coactivation. Additionally, tension, depression, fatigue, and frustration were positively associated with RMSSD reflecting increases in parasympathetic activation. The autonomic coactivation may represent an integrated response to specific cognitive reactions such as the orienting response.

• Safety and Health at Work
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• v.6 no.3
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• pp.256-262
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• 2015

Background: Heart attack is the most common cause of line-of-duty death in the fire service. Daily aspirin therapy is a preventative measure used to reduce the morbidity of heart attacks but may decrease the ability to dissipate heat by reducing skin blood flow. Methods: In this double-blind, placebo-controlled, crossover study, firefighters were randomized to receive 14 days of therapy (81-mg aspirin or placebo) before performing treadmill exercise in thermal-protective clothing in a hot room [$38.8{\pm}2.1^{\circ}C$, $24.9{\pm}9.1%$ relative humidity (RH)]. Three weeks without therapy was provided before crossing to the other arm. Firefighters completed a baseline skin blood-flow assessment via laser Doppler flowmetry; skin was heated to $44^{\circ}C$ to achieve maximal cutaneous vasodilation. Skin blood flow was measured before and after exercise in a hot room, and at 0 minutes, 10 minutes, 20 minutes, and 30 minutes of recovery under temperature conditions ($25.3{\pm}1.2^{\circ}C$, $40.3{\pm}13.7%\;RH$). Platelet clotting time was assessed before drug administration, and before and after exercise. Results: Fifteen firefighters completed the study. Aspirin increased clotting time before and after exercise compared with placebo (p = 0.003). There were no differences in absolute skin blood flow between groups (p = 0.35). Following exercise, cutaneous vascular conductance (CVC) was $85{\pm}42%$ of maximum in the aspirin and $76{\pm}37%$ in the placebo groups. The percentage of maximal CVC did not differ by treatment before or after recovery. Neither maximal core body temperature nor heart rate responses to exercise differed between trials. Conclusion: There were no differences in skin blood flow during uncompensable heat stress following exercise after aspirin or placebo therapy.

• International Journal of Highway Engineering
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• v.14 no.5
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• pp.75-83
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• 2012

PURPOSES: Suggestion of asphalt binder constitutive model based on time-temperature superposition principle and overstress concept in order to describe behavior of asphalt binders. METHODS: A series of temperature sweep tests and multiple stress creep and recovery(MSCR) tests are performed to verify the applicability of time-temperature superposition principle(t-Ts) and to develop viscoelastoplastic constitutive equation based on overstress concept. For the tests, temperature sweep tests at various high temperature and various frequency and MSCR test at $58^{\circ}C$, $64^{\circ}C$ $70^{\circ}C$, $76^{\circ}C$, and $82^{\circ}C$ are performed. From the temperature sweep tests, dynamic shear modulus mastercurve and time-temperature shift function are built and the shift function and MSCR at $58^{\circ}C$ are utilized to determine model coefficients of VBO model. RESULTS: It is observed that the time-temperature shift function built at low strain level of 0.1% is applicable not only to 1.0% strain level temperature sweep test but also maximum 500,00% strain level of MSCR test. As well, the modified VBO model shows perfect prediction on MSCR measured strain at the other temperatures. CONCLUSIONS: The Time-temperature superposition principle stands hold from very low strain level to very high strain level and that the modified VBO model can be applicable for various range of strain and temperature region to predict elastic, viscoelastic, and viscoplastic strain of asphalt binders.

• Structural Engineering and Mechanics
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• v.59 no.1
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• pp.37-57
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• 2016

Reservoir geomechanics can play an important role in hydrocarbon recovery mechanism. In $CO_2$-EOR process, reservoir geomechanics analysis is concerned with the simultaneous study of fluid flow and the mechanical response of the reservoir under $CO_2$ injection. Accurate prediction of geomechanical effects during $CO_2$ injection will assist in modeling the Carbon dioxide recovery process and making a better design of process and production equipment. This paper deals with the implementation of a program (FORTRAN 90 interface code), which was developed to couple conventional reservoir (ECLIPSE) and geomechanical (ABAQUS) simulators, using a partial coupling algorithm. A geomechanics reservoir partially coupled approach is presented that allows to iteratively take the impact of geomechanics into account in the fluid flow calculations and therefore performs a better prediction of the process. The proposed approach is illustrated on a realistic field case. The reservoir geomechanics coupled models show that in the case of lower maximum bottom hole injection pressure, the cumulative oil production is more than other scenarios. Moreover at the high injection pressures, the production rates will not change with the injection bottom hole pressure variations. Also the FEM analysis of the reservoir showed that at $CO_2$ injection pressure of 11000 Psi the plastic strain has been occurred in the some parts of the reservoir and the related stress path show a critical behavior.

• The Korean Journal of Pain
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• v.36 no.1
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• pp.72-83
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• 2023

Background: Globally, spinal cord injury (SCI) results in a big burden, including 90% suffering permanent disability, and 60%-69% experiencing neuropathic pain. The main causes are oxidative stress, inflammation, and degeneration. The efficacy of the stem cell secretome is promising, but the role of human neural stem cell (HNSC)-secretome in neuropathic pain is unclear. This study evaluated how the mechanism of HNSC-secretome improves neuropathic pain and locomotor function in SCI rat models through antioxidant, anti-inflammatory, anti-matrix degradation, and neurotrophic activities. Methods: A proper experimental study investigated 15 Rattus norvegicus divided into normal, control, and treatment groups (30 µL HNSC-secretome, intrathecal in the level of T10, three days post-traumatic SCI). Twenty-eight days post-injury, specimens were collected, and matrix metalloproteinase (MMP)-9, F2-Isoprostanes, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β, and brain derived neurotrophic factor (BDNF) were analyzed. Locomotor recovery was evaluated via Basso, Beattie, and Bresnahan scores. Neuropathic pain was evaluated using the Rat Grimace Scale. Results: The HNSC-secretome could improve locomotor recovery and neuropathic pain, decrease F2-Isoprostane (antioxidant), decrease MMP-9 and TNF-α (anti-inflammatory), as well as modulate TGF-β and BDNF (neurotrophic factor). Moreover, HNSC-secretomes maintain the extracellular matrix of SCI by reducing the matrix degradation effect of MMP-9 and increasing the collagen formation effect of TGF-β as a resistor of glial scar formation. Conclusions: The present study demonstrated the mechanism of HNSC-secretome in improving neuropathic pain and locomotor function in SCI through antioxidant, anti-inflammatory, anti-matrix degradation, and neurotrophic activities.