• Asian Journal of Turfgrass Science
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• v.25 no.1
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• pp.112-117
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• 2011

This research was conducted to determine the effect of the pre-treatment of mulberry charcoal on the salt tolerance response in Kentucky bluegrass 'Perfection'. As this results, 400 mM NaCl treatment reduced turf growth such a fresh and dry weight, and induced physiological damages like decreased chlorophyll content and increased electrolyte leakage. The pre-treatment of mulberry charcoal, however, mitigated those growth and physiological responses associated with NaCl stress, regardless of the concentrations of charcoal solution. Furthermore, it was observed that higher K ion concentration by mulberry charcoal pre-treatment reduced Na ion in shoot. This research suggests to be a possibility of planting turf grasses in reclaimed land or higher salt accumulated area using a mulberry charcoal treatment.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.819-826
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• 2013

The black seabream Acanthopagrus schlegelii is an important species for aquaculture in Korea. There are, however, no reports on the physiological responses to hypoxia in this species. The objective of this study was to evaluate the effects of acute hypoxia on the physiological stress responses (plasma cortisol as the primary response, and plasma glucose, hematocrit (Ht), hemoglobin (Hb), sodium, chloride, osmolality, AST, ALT and total protein as the secondary responses) of the fish. The experimental fish were exposed to 0.5 ppm dissolved oxygen (DO) in the seawater via two methods (progressive stepwise decline (Exp. I), and direct decline (Exp. II)). A highly significant increase was detected in plasma cortisol levels due to the hypoxia treatments, and fish in Exp. I had hormone levels that were significantly higher than the fish in Exp. II. For plasma glucose, there was no significant difference between the Exp. I fish and the control fish, whereas Exp. II fish showed significantly higher plasma glucose levels than Exp. I fish and control fish. Ht values increased in both hypoxia treatments; however, Hb concentrations increased only in Exp. I. Although plasma chloride levels were unaffected by acute hypoxia, plasma sodium and osmolality levels increased in Exp. I. Progressive hypoxia (Exp. I fish) increased plasma AST, ALT and total protein. These results suggest that the value and direction of changes to the investigated parameters can be used to determine the resistance of black seabream to acute hypoxia.

• Korean Journal of Veterinary Research
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• v.56 no.4
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• pp.215-221
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• 2016

Due to the shortage of the fingerling/juvenile mud loach, Misgurnus mizolepis in Korea, these fish have been imported from China. However, the mortality rate during and after their transportation is very high. In this study, we examined various physiological and histological parameters to evaluate the effect of salt treatment on the survival and recovery of mud loaches in holding farms during the quarantine process. Glucose, osmolality, $Na^+$, $Cl^-$, and histological changes were assessed for three different salinities. Non-treated fish (control 0.0%) exhibited lower levels of osmolality, and $Na^+$ and $Cl^-$ concentrations compared with those kept in solar salt solution (0.5% and 1.0%). Glucose levels in control fish were higher than those in fish exposed to 0.5% and 1.0% solar salt solution. Histologically, control fish showed thinner epidermis of skin, branchial hyperplasia and lamellar fusion with an abundance of eosinophilic granule cell-like cells. After solar salt solution treatment, damaged gill structures in the fish almost recovered within 5 days. The present study demonstrates that mud loaches transported from China suffer from skin and gill damage and physiological dysfunction which may increase the mortality and morbidity. Moreover, saline treatment might alleviate the stress responses and ionic/osmotic imbalances, and help heal gill damage.

• Journal of Animal Science and Technology
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• v.63 no.4
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• pp.904-918
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• 2021

This study was conducted to investigate the effect of cooling systems on reproductive performance, body temperature, blood metabolites, and the intestinal microbiome in early gestating sows exposed to high ambient temperature. In total, 39 pregnant sows (Landrace × Yorkshire; 2 parities) were randomly assigned to and maintained in the following three treatment groups (13 sows per group) over days 0 to 35 of pregnancy: (i) air cooling (AC; 26.87 ± 1.23℃), (ii) water-drip cooling (WC; 28.81 ± 0.91℃), and (iii) a lack of cooling with heat stress (HS; 30.72 ± 0.70℃). Backfat thickness was measured before and after HS. Feces were collected on day 0 and 35 d of the trial for microbiome analysis, whereas blood was taken at day 35 of pregnancy and analyzed. Reproductive performance and physiological responses were identified at day 35. Respiration rate along with rectal and skin temperatures were lower (p < 0.05) in the AC group than in the HS and WC groups. Serum blood urea nitrogen values were increased (p < 0.05) in the WC group compared with those measured in the AC and HS groups. Triiodothyronine was found at greater levels (p < 0.05) in the AC than in the HS group. Reproductive performance was not affected by the cooling systems. At the phylum level, fecal pathogenic Spirochaete and Euryarchaeota were found in higher numbers (p < 0.05) in all groups after HS. Similarly, at the genus level, the amount of Treponema was greater (p < 0.05) in all groups after HS. In conclusion, our results suggest that AC or WC can ameliorate or mitigate the adverse effects of HS on the physiological parameters of pregnant sows reared under high temperatures.

• Journal of Animal Science and Technology
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• v.63 no.4
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• pp.872-883
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• 2021

We evaluated the effects of heat stress on physiological responses and milk production in Holstein and Jersey cows reared in Korea. The mean average temperature-humidity index (THI) increased significantly from May to August and then decreased until October. The mean average rectal temperature (RT) was increased in Holstein cows compared with Jersey cows, as the THI values increased from 61 to 85. The average respiratory rate (RR) was increased in Jersey cows compared with Holstein cows when the THI value increased from 61 to 85. The average surface temperature of the rumen and udder was higher in Jersey cows than in Holstein cows when the THI value increased from 61 to 85. No significant difference was noted with respect to relative serum volumes between the breeds and THI ranges, but we measured significant changes in serum pH in Holstein and Jersey cows when the THI value increased from 61 to 85. Milk production was not significantly changed in Holstein cows when the THI increased from 61 to 85, but milk production and milk protein content were significantly altered in Jersey cows when the THI increased from 61 to 85. Current study suggests that Holstein cows still have an advantage in terms of the economic returns of dairy farms in Korea. Therefore, further research is required regarding the heat tolerance of Jersey cows in Korean climatic conditions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.1
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• pp.39-44
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• 2005

This study was conducted to examine the physiological and biochemical responses against UV-B radiation in the seedling of 15 different rice cultivars, having the different physiological sensitivities. Out of 15 rice cultivars tested, moderate and susceptible groups showed significant decreases in biomass and RGR (relative growth rate). Contents of total chlorophyll were reduced remarkedly by irradiation of UV-B. In all rice cultivars tested, the content of chlorophyll a was strongly decreased, while the contents of chlorophyll b were slightly reduced without showing clear different among three groups and 15 cultivars. Carotenoid content was largely reduced by UV-B radiation, whereas polyamine content was moderately increased. The contents of MDA (malondialdehyde) that reflect the level of lipid peroxidation of cell membranes were clearly increased by UV-B stress, showing higher content in susceptible cultivars than moderate and torelant cultivars. The physiological important parameters highly related to visible injury were leaf color, chlorophyll, carotenoid, and lipid peroxidation, whereas biomass and polyamines were not closely correlated. Based on this results, it was concluded that changes of visible injury and the contents of chlorophyll and MDA could be adequately applied and utilized as physiological indicators to UV-B radiation.

• Journal of the Korean Society of Safety
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• v.35 no.1
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• pp.62-69
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• 2020

Most people suffer from stress during day life because modernized society is very complex and changes fast. Because stress can affect to many kind of physiological phenomena it is even considered as a disease. Therefore, it should be detected earlier, then must be released. When a person is being stressed several bio-signals such as heart rate, etc. are changed. So, those can be detected using medical electronics techniques. In this paper, stress assessment system is studied using random forest algorithm based on heart rate, RR interval and Galvanic skin response. The random forest model was trained and tested using the data set obtained from the bio-signals. It is found that the stress assessment procedure developed in this paper is very useful.

• Journal of the Ergonomics Society of Korea
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• v.21 no.2
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• pp.59-70
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• 2002

This paper is about the evaluation of stress response and recovery using biosignals and fuzzy theory. We caused mental stress by means of a coin-stacking task. During the experiment, 4 kinds of biosignals, including frontalis EMG, ECG, peripheral skin temperature and skin conductance level, were acquired. Then, the degree of stress was assessed by synthetically those signals using fuzzy inference. From the fuzzy inference result, the parameters (amount of physiological change / amount of imposed stress) and (time to 25% recovery), which represent response and recovery respectively, were derived. We made a two-dimensional point graph using the response parameter as an abscissa and the recovery parameter as an ordinate for each subject.

• Journal of the Ergonomics Society of Korea
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• v.17 no.2
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• pp.33-48
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• 1998

This paper illustrates the application of Fuzzy Theory and Analytic Hierarchy Process(AHP) for developing Occupational Stress Index(OSI). The purpose of the OSI development is for future prediction and problem solving of prevailing occupational stress. In developing OSI, the concept of fuzzy set theory was introduced to determine the existence and level of perceived occupational stress instead of actually measuring the strain parameters. The AHP is adopted to collect different weighting factors, since there exist various perceptions and responses to the occupational stress by different individuals. The validation study revealed that the OSI is a reliable predictor of work-related accident and illness and the physiological health of employees. Creating preventive measures, such as early detection of stress, proper placement and promotion of employees, and job enlargement will be possible by using this OSI effectively.

• Journal of Mechanical Science and Technology
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• v.15 no.7
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• pp.965-973
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• 2001

It is well established that arteries are subjected to residual stress. Due to the effect of residual stress, the arteries open to a horse-shoe shape when a longitudinal cut is made on an excised arterial segment. Previously, the residual stress has been quantified by the opening angle of the horse-shoe shape. We have employed a finite element analysis of the open arterial segment to restore the same to the original cylindrical shape and computed the circumferential strain as well as the stress distribution in the wall. In this study, the stress distribution in the femoral arteries of miniswine was computed with and without the residual stress for a range of transmural pressures. Our analysis showed that the residual stress has the effect of redistribution of the circumferential stresses between the intima and the adventitia under physiological loading. The redistribution of the stress with the inclusion of residual stress may be important in the studies on effect of wall stresses on the endothelial and vascular smooth muscle cells.