• Asian Journal of Turfgrass Science
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• v.15 no.4
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• pp.169-179
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• 2001

This study was conducted to determine the effect of root zone cooling on growth and quality of turfgrasses including Kentucky bluegrass (Poa pratensis L.‘Nuglade’), perennial ryegrass (Lolium perenne L.‘Accent’), tall fescue (Festuca arundinacea Schreb.‘Pixie’), and Japanese lawngrass (Zoysia japonica Steud.) in simulated athletic field during summer season in Korea. Mineral contents in clippings of turfgrasses grown at different soil mixtures and temperatures were also analyzed. Root zone cooling (approximately 4~6$^{\circ}C$ lower than that of untreated-control) resulted in good uniformity, little disease incidence and higher level of chlorophyll contents in cool-season turfgrasses. The effectiveness of root zone cooling in protecting disease incidence from high temperature stress was the most manifest in perennial ryegrass compared to others. Fresh clipping weight in treatment of root zone cooling was increased approximately 2 times in Kentucky bluegrass and perennial ryegrass, and 2.5 times in tall fescue compared to those of control. There was higher growth rate in a soil mixture composed of 80% peat moss ＋10% sand ＋10% soil (v/v/v) than in that of 80% pea moss ＋20% sand (v/v), Mineral contents of N, P, K, Ca, and Mg in clippings of three species of cool-season turfgrasses were significantly increased in treat-ment of root zone cooling but this was not found in Japanese lawngrass. Results showed that root zone cooling has a benefit in keeping good quality and growth of cool-season turfgrasses in sports field under supraoptimal ambient temperature during summer season.

• Journal of Life Science
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• v.17 no.12
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• pp.1649-1653
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• 2007

High temperature stresses have caused growth inhibition and delayed heading in highland cultivation Chinese cabbage during summer in Korea. We have studied high temperature stress responses in the terms of changes of inorganic components and proteins by proteomic analyses. Insufficiencies of nitrogen and phosphorus have affected growth rate and calcium deficiency has caused blunted heading. Proteins extracted from Brassica seedling grown at the altitude of 600m and 900m in the Mount Jilun were extracted and analysed by 2-dimentional polyacrylamide gel electrophoresis. Profiles of protein expression was then analyzed by 2-dimentional gel analyses. Protein spots showing different expression level were picked using the spot handling workstation and subjected to MALDI-TOF MS. Total 48 protein spots were analyzed by MALDI-TOF MS and 30 proteins spots out of 48 were identified by peptide mass fingerprinting analyses. Fourteen proteins were up-regulated in extracts from the altitude of 900m and they were identified as oxygen-evolving proteins, rubisco activase and ATPase etc. Sixteen proteins were up-regulated in extracts from the altitude of 600m and they were identified as glutathione S-transferase(1, 28kD cold induced- and 24 kD auxin-binding proteins) and salt-stress induced protein etc. These stress-induced proteins were related to the mediated protective mechanism against oxidative damage during various stresses. The results indicated that physiological phenomenon in response to high temperature stresses might be resulted by complex and multiple array of responses with drought, heat, oxidative, salt, and cold by high temperature.

• Resources Recycling
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• v.29 no.1
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• pp.25-34
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• 2020

Electrochemical Quartz Crystal microbalance is a tool that is capable of measuring nanogram-scale mass change on electrode surface. When applying alternating voltage to the quartz crystal with metal electrode formed on both sides, a resonant frequency by inverse piezoelectric effect depends on its thickness. The resonant frequency changes sensitively by mass change on its electrode surface; frequency increase with metal dissolution and decrease with metal deposition on the electrode surface. The relationship between resonant frequency and mass change is shown by Sauerbrey equation so that the mass change during metal dissolution can be measured in real time. Especially, it is effective in the case of reaction mechanism and rate studies accompanied by precipitation, volatilization, compound formation, etc. resulting in difficulties on ex-situ AA or ICP analysis. However, it should be carefully considered during EQCM experiments that temperature, viscosity, and hydraulic pressure of solution, and stress and surface roughness can affect on the resonant frequency. Application of EQCM was shown as a case study on leaching of platinum using aqueous chlorine for obtaining activation energy. A platinum electrode of quartz crystal oscillator with 1000 Å thickness exposed to solution was used as leaching sample. Electrogenerated chlorine as oxidant was purged and its concentration was controlled in hydrochloric acid solution. From the experimental results, platinum dissolution by chlorine is chemical reaction control with activation energy of 83.5 kJ/mol.

• Korean Journal of Remote Sensing
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• v.37 no.2
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• pp.211-220
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• 2021

Land Surface Temperature (LST) is one of the useful parameters to diagnose the growth and development of crop and to detect crop stress. Unmanned Aerial Vehicle (UAV)-based LST (LSTUAV) can be estimated in the regional spatial scale due to miniaturization of thermal infrared camera and development of UAV. Given that meteorological variable, type of instrument, and surface condition can affect the LSTUAV, the evaluation for accuracy of LSTUAV is required. The purpose of this study is to evaluate the accuracy of LSTUAV using LST measured at ground (LSTGround) under various meteorological conditions and growth phases of garlic crop. To evaluate the accuracy of LSTUAV, Relative humidity (RH), absolute humidity (AH), gust, and vegetation index were considered. Root mean square error (RMSE) after minimizing the bias between LSTUAV and LSTGround was 2.565℃ under above 60% of RH, and it was higher than that of 1.82℃ under the below 60% of RH. Therefore, LSTUAV measurement should be conducted under the below 60% of RH. The error depending on the gust and surface conditions was not statistically significant (p-value < 0.05). LSTUAV had reliable accuracy under the wind speed conditions that allow flight and reflected the crop condition. These results help to comprehend the accuracy of LSTUAV and to utilize it in the agriculture field.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.3
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• pp.253-264
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• 2010

This study investigates the relationship between daily mortality and heat stress in Seoul, using perceived temperatures (PT) derived from a heat budget model. During the summer season, observed PT intensity showed the biggest magnitude of summer heat stress from the middle 10 days of July to the first 10 days of August. The elderly (65 and above) were found to be the most vulnerable to heat stress. The threshold PT, with a significant increase in excess mortality, was $38^{\circ}C$. No time lagged effect was observed with summer heat stress, while a high correlation was observed between anomalies in PT and relative deviation of mortality. A comparison of the heat index and the discomfort index with excess mortality revealed that the discomfort index underestimated excess mortality, whereas the heat index could not appropriately explain the increase in excess mortality correlated with the increase in excess heat. In contrast, PT was found to be the weather element that best represents excess mortality due to heat stress, and is thus expected to serve as a more reliable forecast index of human biometeorology.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.1
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• pp.107-114
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• 2016

PURPOSE: The purpose of the present study is to apply foot therapy at diverse temperatures to students in the Department of Physical Therapy who are experiencing clinical practice to find the most effective foot-bath temperatures for stress relief. METHODS: Sixty four students in the department of physical therapy who were undergoing the course on clinical practice participated in the present study. SDNN, TP, LF, and HF were measured to compare the control group, cold group, tepid group, and the hop group. The data were analyzed through analysis of covariance and paired t-tests. RESULTS: Although SDNN increased in the cold group and the tepid group, the differences were not statistically significant. TP and LF showed statistically significant increases in the cold group. In comparisons between the groups, the cold group showed statistically significant increases compared to the control group and the hot group. Although the tepid group also showed increases, the differences were not statistically significant. HF statistically decreased in the hot group. In comparisons between the groups, statistically significant differences appeared between the cold group and the hot group. CONCLUSION: Cold foot-bath was the most effective therapy on the stress of students in the department of physical therapy who were experiencing clinical practice. Tepid foot-bath had the same directivity but showed no statistically significant difference. Hot foot-bath was shown to rather increase stress.

• Microbiology and Biotechnology Letters
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• v.44 no.3
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• pp.349-354
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• 2016

A variety of nuruks collected in different areas in Korea were explored to isolate sixty yeast strains that was able to grow at 44℃. MBY/L1569 strain, which showed the highest growth rate, was selected and identified as Pichia farinosa (Millerozyma farinosa). The isolated strain exhibited superior resistance to heat, acid, and alkali compared with those of P. farinosa KCTC27412 as a control strain. The specific growth rate of P. farinosa MBY/L1569 at 46℃ was 0.37 ± 0.05 h⁻¹, and the highest specific growth rate of 0.50 ± 0.02 h⁻¹ was obtained when it was grown at pH 7.0 and 37℃ with 50 g/l (w/v) glucose as the carbon source. Under optimum growth conditions, strain MBY/L1569 produced ethanol 19.66 ± 0.68 g/l from glucose 50 g/l, with an approximate yield of 40%. P. farinosa MBY/L1569 was deposited at the Korean Collection for Type Cultures as pichia farinosa KCTC27753.

• Microbiology and Biotechnology Letters
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• v.43 no.2
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• pp.91-96
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• 2015

Prions are proteinaceous infectious particles that cause neurodegenerative diseases, such as scrapie in sheep, bovine spongiform encephalopathy in cattle and Creutzfeldt-Jakob disease (CJD) in humans. Although the detailed process, regarding the abnormal conversion of prion proteins (PrP), remains to be fully elucidated, a number of environmental factors appear to affect the formation of misfolded PrP, termed PrP^Sc. Because oceanic algae contain mycosporine-like amino acids (MAAs), which exhibit cellular defensive activities under a variety of stress conditions, we investigated the level of PrP^Sc in prion-infected neuroblastoma cells using mycosporine-glycine, porphyra-334 and shinorine. When judged by the level of protease-resistant PrP^Sc in western blots, porphyra-334 and shinorine increased the level of PrP^Sc in cells, but mycosporine-glycine did not. The current results indicate that the MAAs tested in this study enhance the formation of PrP^Sc.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.2
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• pp.75-82
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• 2004

Zero Voltage Transition Pulse Width Modulation (ZVT-PWM) converter with active snubber circuit was proposed on this paper. The converter that has been proposed snubber circuit can be operated at the condition of light load range, and this converter is turned on and off near by Zero Voltage Switching (ZVS) or Zero Current Switching (ZCS). If the stress of voltage and current are not occurred at the main switch and main diode, we subjected the allowed level of voltage and current on the auxiliary switch and auxiliary diodes. By proposed 750[W], 80[KHz] PWM boost converter to apply soft switching on the power of total output, the loss of main switch to compare with hard switching was reduced about 27[％], and the loss of total circuit was reduced about 36[％]. The total efficiency was increased about 6[％] to compare with general converter.

• Journal of Biomedical Engineering Research
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• v.33 no.4
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• pp.194-201
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• 2012

This study was designed to investigate the effect of a combined stimulus which was composed of chiropractic massage and thermotherapy on the relief of mental and physical stress. Fifteen healthy male subjects were treated with three type of stimuli; control (without any stimulus), a single stimulus (only chiropractic) and a combined stimulus. To evaluate the effects of stimuli, visual analogue scale (VAS), trunk extension, electromyogram (EMG) on erector spinae muscle and electrocardiogram (ECG) were measured and analyzed before and after stimuli. In the control group, there were no significant changes in EMG root mean square (RMS) value and low Frequency/high Frequency (LF/HF) ratio (p > 0.05, p > 0.05). However, both stimulus groups showed significant increases in trunk extension and EMG RMS values (p < 0.05, p < 0.05), but significant decreases in LF/HF ratios (p < 0.05). Particularly the decrement rate in LF/HF ratio was significantly higher in the combined stimulus group than that in the single stimulus group (p < 0.05). Also, a significantly lower VAS was recorded after combined stimulus. Our findings indicate that the combined stimulus might not only improve flexibility and strength of muscle, but also active parasympathetic nerve activity. The combined stimulus may thus contribute to relieve the stress and to enhance the muscle function.