• Journal of Food Hygiene and Safety
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• v.6 no.3
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• pp.147-155
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• 1991

Enterotoxigenic E. coli is one of the major causative agents of the infantile diarrhea and traveler's diarrhea. The heat-stable enterotoxin(ST) is thought to be a virulence factor in the pathogenesis of the diarrhea and to be a maker for identification of the enterotoxingeic E. coli from non pathogenic E. coli. The isolate of enterotoxigenlc E. coli was isolated from swine during 1989 year(from 5 to 10 month) in the Kyong-gi and Chung-Cheong provinces, and three strains(KM-4, KM-7 and KM-12) was selected from 189 isolates of ST producing E. coli. The detection of a ST produced of the isolated E. coli was performed by the infant mouse assay(IMA). This study was designed to know optimal conditions for the production of the ST and the molecular properties of plasmids of the enterotoxigenic E. coli. Amount of ST produced were the most at initial pH 8.5~9.0 of succinate salts medium culture. The cultural time of the same medium was accumulated the highest level of ST was at the 14 to 16 hours, and then stationary phase was at the 20 hours. From this experiment the KM-7 strain was selected among ST producing strains by IMA. Partial plasmid-curing experiment was done to select plasmid encoding for ST among other plasmids and then comparing the plasmid pattern of ST producing strain(KM-7) with those of other ST non-producing strains, it is found that ST gene exists on the about 80 Kbp plasmid. Each fragment of this plasmid digested with EcoRl was ligated to vector pBR 322 and transformed into E. coli K-12. A clone producing ST(eKT 53) was selected by IMA. The EcoRl digestion pattern of the isolated plasmid(pKD 37) from the ST producing clone it is indicated that the size of the inserted fragment in eKT 53 strain is 16 Kbp. The cultured supernatant of eKT 53 strain was positive result of ST production in IMA.

• Journal of Life Science
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• v.21 no.11
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• pp.1636-1640
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• 2011

Alzheimer's disease (AD) is a progressive neurodegenerative disease, resulting in the loss of cognitive function. Mitochondrial aldehyde dehydrogenase (ALDH2) has been proposed to be a risk factor for the development of AD, but there is still controversy about that. In this study, we demonstrated the role of ALDH2 enzyme activity on amyloid-beta (A${\beta}$) and nuclear factor kappa B (NF-${\kappa}B$) expression in mice brain following ethanol exposure for 8 weeks. Five male Aldh2 (+/+) and Aldh2 (-/-) mice, 8 weeks-old of age (C57BL/6J strain), in each group were exposed to ethanol for 8 weeks (2 g/kg wt./day) using gavage. Those in the control groups received 0.9% saline alone. Results showed a difference in expression level of A${\beta}$ in the hippocampus after ethanol exposure according to the ALDH2 enzyme activity (p<0.05), but not in the level of NF-${\kappa}B$). Our results suggest a possibility that ALDH2 enzyme activity may be an important role in the development of AD.

• The Journal of Dong Guk Oriental Medicine
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• v.7 no.1
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• pp.99-117
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• 1998

Objective This experimental study was designed to investigate effects of Bo-joong-ik-gi-tang administration among long distance runners on changes of the energy and electrolyte metabolism. Materials and Methods All subjects were divided randomly with two groups, Bo-joong-ik-gi-tang Group (N=4) and control group (N=4) and performed to run the 400m track with 70% of HR max about 1 hour. The blood samples were collected from antecubital vein by 5ml syringes at before exercise, immediately after exercise, recovering-10 min. recovering-30 min, recovering-1 hour. These samples were used to analyze for the factors of the change on metabolic responses. First, the primary factors on the changes of the energy metabolism were checked ; Glucose, Free fatty acid, Lactate, LDH. Second, the primary factors on the changes of the electrolyte metabolism were checked ; Na+, CI-. K+. Results 1. The change of the energy metabolism 1) Glucose response was not shown significant difference between two groups. 2) Free fatty acid response in Bo-joong-ik-gi -tang group was significantly increased at recover-10 min. 3) Lactate response in Bo-joong-ik-gi-tang group was significantly decreased at immediately after exercise, recover-10 min, recover-30 min. 4) LDH response was not shown significant difference between two groups. 2. The change of the electrolyte metabolism 1) Na+ response in Bo-joong-ik-gi-tang group was shown significant difference between two groups at before exercise. 2) Cl- response in Bo-joong-ik-gi-tang group was significantly increased at before exercise, immediately after exercise. 3) K+ response in Bo-joong-ik-gi-tang group was significantly increased at recover-10 min. Conclusion According to the above results, it was shown that Bo-joong-ik-gi-tang had the positive effects on changes of the energy and electrolyte metabolism for the long distance runners.

• Journal of Life Science
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• v.19 no.4
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• pp.423-428
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• 2009

Selenium was investigated using human origin preadipocytes to see whether it possesses preventive or therapeutic effects for obesity. Unveiling the potential of selenium in the reduction of adipogenesis can help predict the therapeutic capabilities of selenium in obesity. In the present study, the molecular mechanism of the inhibition of adipogenesis by selenium was explored to unravel the involvement of the AMP-activated protein kinase. There is emerging evidence that AMPK, a sensor of cellular energy status, is a possible molecular target of controlling adipocyte differentiation on the basis of discovery that AMPK is responsible for the major metabolic responses to exercise, and integration of nutritional and hormonal signals to modulate feeding behavior or energy expenditure in the hypothalamus. Treatment of selenium resulted in inhibition of the adipocyte differentiation process and induction of mature apoptosis in 3T3-L1 adipocytes. We hypothesized that selenium may exert anti-adipogenic potential though modulating AMPK. We have found that selenium significantly activated AMPK and phosphorylated its substrate acetyl-CoA carboxylase ($ACC-serine^{79}$) during the inhibitory process of adipocytes. Also, the inhibition process of adipocyte differentiation by selenium was comparable to either reveratrol or a synthetic AMPK activator, AICAR (5-aminoimidazole-4-carboxamide-1-${\beta}$-D-ribofuranoside). To evaluate the involvement of AMPK in anti-lipogensis, we applied AICAR and Compound C, an AMPK inhibitor, to 3T3-L1-adipocytes and found that AMPK is required for the adipocyte differentiation blocking process. These results suggest that selenium has a potential to control adipogenesis and that this effect is mediated by AMPK, an essential kinase for both inhibition of adipocyte differentiation and apoptosis of mature adipocytes.

• Korean Journal of Animal Reproduction
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• v.23 no.1
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• pp.1-12
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• 1999

The present study was conducted to find the effects of different cadmium(Cd) levels in diets on clinical toxicity, sperm capacity and histopathological changes in rats. Thirty male rats of Sprague-Dawley weighing 125.3$\pm$15.2g were randomly blocked into five groups according to body weights. Five levels of Cd in AIN-76 purified diet(0, 25, 50, 100 and 250 ppm) had been fed for 8 weeks. Cadmium was supplemented with a form of CdCl$_2$. 1. After 8 weeks of Cd intake had resulted in apparent cadmium intoxication; reduced growth rate, enlarged kidney and testis, decreased hematocrit value and hemoglobin content in response to supplemented Cd levels in the diets. 2. Cadmium accumulation in liver and kidney showed a tendency to increase in cadmium-exposed groups. The levels of metallothionein were also significantly elevated in the tissues of liver in response to the levels of Cd supplemented(P＜0.05). 3. Although sperm motility was not significantly different among treatments, rats fed Cd tended to have reduced sperm motility but sperm concentration of Cd supplemented groups were significantly lower than that of control(p＜0.05). 4. Based on the findings from gross lesion, rats fed 250ppm of Cd were externally emaciated, had exposed penis and observed atrophies of kidney and testis. Histopathological observation seemed that the liver of groups feeding Cd supplemented diets showed cellular degeneration and accumulation of eosinophilic materials in the capillaries. In kidney, rats fed Cd diets had shown tubular epithelium degeneration and lesions of basophilic materials, while testes were weakened in numbers of spermatid and sporadically enlarged of giant cells.

• Journal of Korean society of Dental Hygiene
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• v.2 no.2
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• pp.175-186
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• 2002

Fluoride has been one of the most widely studied caries-preventive agents. But the effect of prenatal administration had been controversies for many years. The results showed that there were no influence on reproductive rate of rats with administration of fluoride from 0 to 20 ppm during pregnancy(p>0.05). There was a trend towards slightly increased the mean ash weight in the 1, 5 and 20 ppm groups, as compared with the control group. However, there was no significant differences among groups (p>0.05). The contents of calcium, magnesium and phosphorus in the total bone were increased with the administrated fluoride concentration were increased, but there were no statistically significant differences among groups(p>0.05). The mean fluoride level of 1 ppm group was significantly higher than that of control group, but the concentrations of fluoride in total carcass pups of 5 and 20 ppm groups were significantly less than that of 1 ppm group(p>0.05). The results of this study indicate that the amount of fluoride transferred to the offspring, which may produce anticariogenic effects in the primary teeth of their effects in the primary teeth of their offspring.

• Journal of Energy Engineering
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• v.28 no.2
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• pp.18-35
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• 2019

The Korea District Heating Corporation operates a gas engine generator with a capacity of $4500m^3 /day$ of biogas generated from the sewage treatment plant of the Nanji Water Recycling Center and 1,500 kW. However, the actual operation experience of the biogas power plant is insufficient, and due to lack of accumulated technology and know-how, frequent breakdown and stoppage of the gas engine causes a lot of economic loss. Therefore, it is necessary to prepare technical fundamental measures for stable operation of the power plant In this study, a series of process problems of the gas engine plant using the biogas generated in the sewage treatment plant of the Nanji Water Recovery Center were identified and the optimization of the actual operation was made by minimizing the problems in each step. In order to purify the gas, which is the main cause of the failure stop, the conditions for establishing the quality standard of the adsorption capacity of the activated carbon were established through the analysis of the components and the adsorption test for the active carbon being used at present. In addition, the system was applied to actual operation by applying standards for replacement cycle of activated carbon to minimize impurities, strengthening measurement period of hydrogen sulfide, localization of activated carbon, and strengthening and improving the operation standards of the plant. As a result, the operating performance of gas engine # 1 was increased by 530% and the operation of the second engine was increased by 250%. In addition, improvement of vent line equipment has reduced work process and increased normal operation time and operation rate. In terms of economic efficiency, it also showed a sales increase of KRW 77,000 / year. By applying the strengthening and improvement measures of operating standards, it is possible to reduce the stoppage of the biogas plant, increase the utilization rate, It is judged to be an operational plan.

• Journal of Plant Biology
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• v.38 no.1
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• pp.47-54
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• 1995

The present study performed the isolation of cytosolic ascorbate peroxidase (APX) isozymes and analyzed the pattern of their activity development and also investigated the change in some other enzyme activities related to the ascorbate-glutathione pathway from the senescing wheat leaves. The aim of this work is to examine the possibility that in the cytoplasm of wheat leaves the ascorbate-glutathione pathway p!ays a significant role in relation to leaf senescence involving an $H_2O_2$ accumulation and then to show the effect of benzyladenine (BA) on that pathway. During the leaf senescence characterized by increases in ChI breakdown and H202 accumulation under the 4-day dark incubation of matured leaf segments; i) no significant increase of total cytosolic APX was observed, ii) a dehydroascorbate reductase (DHAR) activity was decreased rapidly, iii) a slight increase of glutathione reductase (GR) activity occurred. In the BA-treated leaves; however, i) the total activity of APX increased conspicuously, ii) the decrease of DHAR activity was relatively inhibited, iii) the GR activity increase was more enhanced, and iv) the decrease of ascorbate content and the increase of H202 content were retarded as compared with those of control leaves. Three isozymes of cytosolic APX were found by using a native-electrophoretic gel in senescing wheat leaves and two of them occurred with major activity. In the developmental patterns of cytosolic APX isozymes, only two isozyme bands ("a" and "b") appeared with almost constant activity through 4 days of incubation in the control leaves, while one additional weak isozyme band ("c") and a little increase of "b" isozyme activity were detected in the BA-treated leaves. EspeciaUy, the development of "a" isozyme activity increased remarkably compared with that of control leaves. The increased capacity for peroxide scavenging due to the enhanced activity of all 3 enzymes (APX, DHAR, GR) participating in the ascorbate-glutathione pathway in BA-treated leaves suggested that this pathway might playa significant role in the processes related to the wheat leaf senescence.scence.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.4
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• pp.290-295
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• 1989

An incubation study was conducted to examine the effect of soil pH and temperature on nitrification potential of 8 different soil series applied with no-N and 200 ugN/g soil as a compound fertilizer at 60 % moisture content of maximum water holding capacity for 8 weeks, whose series were ranged from acid to mild alkali as Gopyeong(Jincheon, pH 4.51), Yesan(Jincheon, pH 4.54), Jigog(Eumseong, pH 4.71), Songsan(Goesan, pH 5.01), Angye(Seongju, pH 5.34), Banho(Seongju, pH 5.73), Weongog(Jincheon, pH 5.93), and Banho(Seongju, pH 7.70), respectively. Interrelationship between the nitrifiable and the net $NO_3-N$(N added plot-no-N plot) accumulated in the soil and tobacco yield in the no fertilizer plot were investigated as well. 1. Nitrification response was various according to soil characteristics at each temperature condition showing that nitrifiable $NO_3-N$ values of the soils were much higher at $25^{\circ}C$ than $15^{\circ}C$. And difference of nitrification potential affected by temperature was markedly distinguishable from 2 weeks after incubation and was showing a tendency to reduce with increasing of soil pH. 2. At each temperature condition, net $NO_3-N$ accumulated at 2 and 4 weeks after incubation was positively correlated with soil pH. 3. Tobacco yield in the no fertilizer plot was more highly correlated with the values of nitrifiable and net $NO_3-N$ accumulated at $15^{\circ}C$ similar to soil temperature in rhizosphere of early stage of tobacco growth than those at optimum temperature($25^{\circ}C$).

• Korean Journal of Cognitive Science
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• v.15 no.2
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• pp.1-15
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• 2004

The structure of sensibility from motion was developed for the purpose of understanding relationship between sensibilities and physical factors to apply it to dynamic visual display. Seventy adjectives were collected by assessing adequacy to express sensibilities from motion and reporting sensibilities recalled from dynamic displays with achromatic color. Various motion displays with a moving single dot were rated according to the degree of sensibility corresponding to each adjective, on the basis of the Semantic Differential (SD) method. The results of assessment were analyzed by means of the factor analysis to reduce 70 words into 19 fundamental sensibilities from motion. The Multidimensional Scaling (MDS) technique constructed the sensibility space in motion, in which 19 sensibilities were scattered with two dimensions, active-passive and bright-dark Motion types systemically varied in kinematic factors were placed on the two-dimensional space of motion sensibility, in order to analyze important variables affecting sensibility from motion. Patterns of placement indicate that speed and both of cycle and amplitude in trajectories tend to partially determine sensibility. Although color and motion affected sensibility according to the in dimensions, it seemed that combination of motion and color made each have dominant effect individually in a certain sensibility dimension, motion to active-passive and color to bright-dark.