• Korean Journal of Environmental Agriculture
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• v.18 no.1
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• pp.11-17
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• 1999

This experiment was conducted to select and utilize the tolerant rice varieties for ozone stress through comparing the physiological responses. In SOD activity, Backunchalbyeo which treated once by 0.15 ppm $0_3$, Ilpumbyeo and Inbujinado treated twice showed significantly different SOD activity compared with $non-O_3$ treatment. No significant difference of SOD activity in three-times $0_3$ treated Sangnambatbyeo and Hangangchalbyeo was found as compared to ($non-O_3$ treated)control, POD activity, when Sangnammbatbyeo, Hangsngchalbyeo, Ilpumbyeo and Inbujinado were sequently treated by third ozone, showed no significant difference between $O_3$ treatment and $non-O_3$. In the comparison of amino acid content in rice leaf blade between three times $O_3$ treatment and $non-0_3$ treatment in 3 varieties, phenylalanine content represent as increased quantities. Especially, in three times $0_3$ treatment of Sangnambatbyeo, phenylalanine content(O.66 mg/g) was significantly increased as compared with $non-O_3$. Visual-growing characters of Sangnembatbyeo were significantly different between $0_3$ treatment and non-treatment. However, grain-filling rate showed no difference. SOD and POD related to resistant mechanism were high activity. In addition, phenylalanine known as precursor which is synthesized resistant materials was increased by $0_3$ treatment. These results suggested that Sangnambatbyeo which increased SOD and POD activity, and phenylalanine content under ozone stress could be selected as a tolerant variety.

• The Korean Journal of Zoology
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• v.33 no.4
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• pp.461-467
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• 1990

To investigate the neurological effect of acrylamide, whole brain of Intoxicated mouse induced early hindlimbs ataxia was examined by using the methods of SDS-PAGE and two-dimensional electrophoresis. In the gel patterns by SDS-PAGE, when the patterns of each group were compared relatively, there were no remakable changes but in the patterns of 2D-PAGE, some protein alterations were observed. Especially, the spots containing 20 (14,500, 5.64) and 21 (19,900, 6.78) were disappeared, and the spots 9 (31,300, 5.82), 11 (31,300, 5.36) and 19 (16,400, 5.42) showed marked decrease relatively in the case of treatment group. Among these changed spots, the spot 20 (14,500, 5.64) showed higher quantity than that of control group but several spots containing the spots 11 (31,300, 5.36), and 19(16.400, 5.42) were identical or equal to those of control In quantity in the case of recovery group. It seems that acrylamide might already inhibit the brain protein synthesis mechanism at the time of onset of distal neuropathy by participation in the protein metabolism so as to impair the brain regulation ability followed by a malfunction of mouse central nervous system (CNS) and recovery is gradually progressed with the dose and duration dependence after the cessation of acrylamide administration.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.7
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• pp.854-867
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• 2014

In the circumstance that high oil price state is continued over the world, the investment in crude oil development by oil major is a trend of increasing. Recently the number of delivered drill-ship for 5 years has been sharply increased all over the world and about twice than that of past 30 years. As addition to the increase of the drill-ship demand, the operation of drill-ships which is delivered recently is about 3,000 meters, ultra deep sea, on average and the work area is expending. Accordingly the drilling system including the size and length of pipe for drilling has been bigger and bigger and the power supply equipment for operation system also has large capacity. Unlike merchant vessel, high power and high voltage of diesel generators are required for drill-ship for which the demand for V-type 320 bore of diesel generator has increased. It is on the raised that the importance of lubrication oil cleaning for diesel generator on drill-ship which has longer time for construction, and also long term low load operation is unavoidable during commissioning of equipments. Recently it was reported that engine crankpin was damaged due to the hard contact caused by the abnormal wear down(Cam wear) on crankpin and bearing. The same pattern of wear down was found through the inspection on series vessels and the other vessel under commissioning. The purpose of this paper is to analyze of the wear mechanism based on the observation and theories and objective research from actual cases and to prepare the counter measures to avoid foreseeable damage when the lubricating oil is not properly cleaned.

• The Korean Journal of Pesticide Science
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• v.8 no.2
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• pp.79-87
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• 2004

3-Chloro-2-[4-chloro-2-fluoro-5-(5-methyl-3-phenyl-4,5-dihydroisoxazol-5-ylmethoxy)-phenyl]-4,5,6,7-tetrahy dro-2H-indazole(EK-5439) demonstrated rice selectivity and herbicidal activity on annual weeds, such as Echinochloa oryzicola, Monochoria vaginalis, Lindernia pyxidaria, Rotala indica, Aneilema keisak, Cyperus difformis, and Ludwigia prostrata at doses of 16-63 g a.i./ha. However, the application window was limited from pre-emergence to 5 days after transplanting. The control efficacy of EK-5439 on barnyardgrass was 4 times higher than that of oxadiazon. EK-5439 was excellently safe to the 16 different transplanted rice cultivars treated 2 days after transplanting. These compounds have the mechanism of action on the chlorophyll biosynthesis like protoporphyrinogen IX oxidase inhibitors.

• Korean Chemical Engineering Research
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• v.47 no.2
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• pp.169-173
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• 2009

Effects of variations sulfur/accelerator ratio on cross-linking and thermal degradation behavior of NR/CR rubber compounds were studied using both dynamic DSC and non-isothermal TGA. DSC thermograms of the given samples were obtained with several different heating rates, and after cross-liked in DSC, TGA thermograms with the same samples also obtained. Kissinger analysis was applied to assess the activation energies for the cross-linking and thermal decomposition processes. Results showed that the formation and thermal decomposition reaction of the samples occurred in the overall temperature range of $120{\sim}180^{\circ}C$ and $350{\sim}450^{\circ}C$, respectively, exhibiting that data could be well-fittable by Kissinger method. Furthermore, formation activation energy by DSC was estimated as $83.0{\pm}5.0kJ/mol$, which was much smaller than that of degradation by TGA, $147.0{\pm}2.0kJ/mol$. From these results, it was considered that, although variations of sulfur/accelerator ratio in the present experiments affected little on the formation mechanism and/or thermal degradation, they could play roles as the catalysts which lower the activation energy of formation. Because of stabilization after formation reaction, however, they have no more effects on the lowering the activation energy, showing higher values when decomposition, caused by main-chain scissions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.4
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• pp.653-658
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• 2004

Oxidative stress is currently suggested as a mechanism underyling diabetes. Accordingly, the present study was designed to evaluate the effect of Aralia elate water extracts (AEW) on activities of hepatic oxygen free radical generating and scavenging enzymes in streptozotocin (STZ)-induced diabetic rats. Male Wistar rats divided into nondiabetic group, diabetic group, and diabetic-AEW supplemented group. The extract was supplemented in 1.14% of raw Aralia elata/kg diet for 7 weeks. Diabetes was induced by injecting STZ (55 mg/kg BW, ip) once 2 weeks before sacrifying. The hepatic cytochrome P-450 content, xanthine oxidase and aminopyrine N-demethylase activities were significantly lowered in the diabetic group compared to the nondiabetic group. Whereas, the activities of aniline hydroxylase and oxygen free radical scavenging enzymes, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase and glutathione S-transferase, were significantly higher in the diabetic group than in the nondiabetic group. However, the supplementation of AEW normalized these enzyme activities in STZ-induced diabetic rats. When the AEW was supplemented with the diabetic rats, hepatic glutathione content was markedly elevated as well as lipid peroxide level was significantly lowered compared to those of the diabetic group. Thus, these results suggested that AEW supplement enhanced the activities of oxygen species metabolizing enzymes in STZ-induced diabetic rats.

• Journal of Ginseng Research
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• v.42 no.1
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• pp.116-121
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• 2018

Background: Black ginseng (BG) has greatly enhanced pharmacological activities relative to white or red ginseng. However, the effect and molecular mechanism of BG on muscle growth has not yet been examined. In this study, we investigated whether BG could regulate myoblast differentiation and myotube hypertrophy. Methods: BG-treated C2C12 myoblasts were differentiated, followed by immunoblotting for myogenic regulators, immunostaining for a muscle marker, myosin heavy chain or immunoprecipitation analysis for myogenic transcription factors. Results: BG treatment of C2C12 cells resulted in the activation of Akt, thereby enhancing hetero-dimerization of MyoD and E proteins, which in turn promoted muscle-specific gene expression and myoblast differentiation. BG-treated myoblasts formed larger multinucleated myotubes with increased diameter and thickness, accompanied by enhanced Akt/mTOR/p70S6K activation. Furthermore, the BG treatment of human rhabdomyosarcoma cells restored myogenic differentiation. Conclusion: BG enhances myoblast differentiation and myotube hypertrophy by activating Akt/mTOR/p70S6k axis. Thus, our study demonstrates that BG has promising potential to treat or prevent muscle loss related to aging or other pathological conditions, such as diabetes.

• Archives of Plastic Surgery
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• v.40 no.5
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• pp.530-535
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• 2013

Background Platelet-rich plasma (PRP) has more concentrated platelets than normal plasma (approximately 150-400${\times}10^3$ cell/dL). Platelets excrete several growth factors and cytokines that are associated with the healing and regeneration process. However, even though PRP is widely used, the mechanism or actual effect is presently unclear. Therefore, this study was performed to investigate the levels of growth factors and platelet concentration rate. Methods Autologous blood for preparing PRP was obtained from healthy subjects aged 25 to 35 years. The samples were divided into 4 experimental groups (inactivated whole blood, inactivated PRP, activated whole blood with thrombin and calcium chloride, and activated PRP). The platelet counts in the blood were analyzed and the growth factors were quantitatively measured. A statistical analysis was performed by using Dunn's multiple comparison test. Results In the blood cell analysis, the platelet count of the PRP group was approximately 4.25 times higher than that of the whole blood group. In the quantitative analysis of growth factors, the platelet-derived growth factor (PDGF)-AB, PDGF-BB, and transforming growth factor-${\beta}$ of the inactivated and activated PRP groups were higher than those of the inactivated and activated whole blood groups (P<0.05). Conclusions In this study, the platelet count and the levels of PDGF-AB and PDGF-BB in the PRP were determined. Further, more research is required on the bioactivity level of the growth factors secreted during the process of PRP preparation and the potency of growth factors that can be exerted physiologically in vivo.

• Journal of Korea Water Resources Association
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• v.37 no.3
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• pp.219-231
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• 2004

The use of air diffuser system to ameliorate the reservoir by breaking stratification is now widespread. This study focuses on the hydrodynamic behavior of bubble plumes, which is the major mechanism of destratification and their combined effect of adjacent plumes on destratification efficiency. By introducing 2-phase Computational Fluid Dynamics(CFD) technique, we could suggest the optimal diffuser spacing having optimal destratification efficiency by simply analyzing the complex destratification procedures varying with the seasonal stratification intensity and bubble flow rate. Lab experiments were also carried out to verify CFD model in thermally stratified fresh water which quite differs from former researches using salts. This study showed that the mixing efficiency strongly depends on the spacing of neighboring plumes. When diffuser spacing is lower than 1.5 times the depth, the combined effect is stronger; as Plume Number(PN) is increased, the efficiency is strongly affected by spacing. If the distance is shorter than the depth of water, the efficiency increases linearly in proportion to PN. Otherwise, the efficiency increases non-linearly. These findings suggest that the combined effect should be more quantitatively taken into consideration for design and operation of air-diffuser destratification system, and recommend that the optimal destratification efficiency will be when plume number is 1000 and the spacing between neighboring diffusers is 1.5 times the depth.

• Journal of The Korean Association For Science Education
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• v.36 no.4
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• pp.581-589
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• 2016

This research aims to find directions for character education in science education and to analyze Nature-Study theoretically as one of the ways to implement character education in science education. In order to accomplish this, references for character education were collected and analyzed to derive the directions for character education in science education, and then the results were verified by expert workshops composed of 2 science education experts and 4 PhD students. Through the consideration of references for Nature-Study in terms of character education, we supposed to confirm that Nature-Study is an efficient way to implement character education in science education. The research resulted in the following: First, science education should establish it's own role in character education by expanding the domains of value and realizing practice-centered character education. Accordingly, 'Expanded model of character education (The domains of the value)' was developed on the basis of 'formation of relationships' with 'nature & environment, spiritual object' and 'The practice-centered character manifested mechanism' empathized 'formation of relationships' and 'practice' was also diagramed. Second, Nature-Study empathized 'Science Education through Nature' can be one of the efficient ways to implement character education in science education. Nature-Study corresponds with the directions of character education in science education because Nature-Study aims for character education in it's educational purpose and emphasizes 'formation of relationships' with 'nature & environment' and 'practice' in the real world. In conclusion, science education should establish it's own role in character education by expanding the domains of value and realizing the practice-centered character education and Nature-Study is efficient ways to implement character education in science education.