• Proceedings of the Plant Resources Society of Korea Conference
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• 2010.10a
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• pp.14-14
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• 2010

Vitamin C (ascorbic acid) is an essential component for collagen biosynthesis and also for the proper functioning of the cardiovascular system in humans. Unlike most of the animals, humans lack the ability to synthesize ascorbic acid on their own due to a mutation in the gene encoding the last enzyme of ascorbate biosynthesis. As a result, vitamin C must be obtained from dietary sources like plants. In this study, we have developed two different kinds of transgenic potato plants (Solanumtuberosum L. cv. Taedong Valley) overexpressing strawberry GalUR and mouse GLoase gene under the control of CaMV 35S promoter with increased ascorbic acid levels. Integration of the these genes in the plant genome was confirmed by PCR and Southern blotting. Ascorbic acid(AsA) levels in transgenic tubers were determined by high-performance liquid chromatography(HPLC). The over-expression of these genes resulted in 2-4 folds increase in AsA intransgenic potato and the levels of AsA were positively correlated with increased geneactivity. The transgenic lines with enhanced vitamin C content showed enhanced tolerance to abiotic stresses induced by methyl viologen(MV), NaCl or mannitol as compared to untransformed control plants. The leaf disc senescence assay showed better tolerance in transgenic lines by retaining higher chlorophyll as compared to the untransformed control plants. Present study demonstrated that the over-expression of these gene enhanced the level of AsA in potato tubers and these transgenics performed better under different abiotic stresses as compared to untransformed control. We have also investigated the mechanism of the abiotic stress tolerance upon enhancing the level of the ascorbate in transgenic potato. The transgenic potato plants overexpressing GalUR gene with enhanced accumulation of ascorbate were investigated to analyze the antioxidants activity of enzymes involved in the ascorbate-glutathione cycle and their tolerance mechanism against different abiotic stresses under invitro conditions. Transformed potato tubers subjected to various abiotic stresses induced by methyl viologen, sodium chloride and zinc chloride showed significant increase in the activities of superoxide dismutase(SOD, EC 1.15.1.1), catalase, enzymes of ascorbate-glutathione cycle enzymes such as ascorbate peroxidase(APX, EC 1.11.1.11), dehydroascorbate reductase(DHAR, EC 1.8.5.1), and glutathione reductase(GR, EC 1.8.1.7) as well as the levels of ascorbate, GSH and proline when compared to the untransformed tubers. The increased enzyme activities correlated with their mRNA transcript accumulation in the stressed transgenic tubers. Pronounced differences in redox status were also observed in stressed transgenic potato tubers that showed more tolerance to abiotic stresses when compared to untransformed tubers. From the present study, it is evident that improved to lerance against abiotic stresses in transgenic tubers is due to the increased activity of enzymes involved in the antioxidant system together with enhanced ascorbate accumulated in transformed tubers when compared to untransformed tubers. At moment we also investigating the role of enhanced reduced glutathione level for the maintenance of the methylglyoxal level as it is evident that methylglyoxal is a potent cytotoxic compound produced under the abiotic stress and the maintenance of the methylglyoxal level is important to survive the plant under stress conditions.

• Journal of Physiology & Pathology in Korean Medicine
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• v.26 no.2
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• pp.189-198
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• 2012

Our former study indicated efficacy of apoptotic cell death on animal study by using Egg white combined Chalcanthite (EC). Clinically, bamboo salt is using because of safety. Hence we investigated a toxicity study for determining safety by adding bamboo salt in former materiel. We had two studies: toxicity of EC and of Bamboo salt with egg white combined Chalcanthite (BC). Both were studied in 1-week single and 5-week repeated oral dose toxicity tests on male Imprinting Control Region mice. In EC, doses used in 1 week single oral dose toxicity tests were 0, 0.05, 0.5, 5 and 50 mg/kg/day and 0, 0.01, 0.05, 0.25 and 0.5 mg/kg/day. In BC, doses used by 0, 0.08, 8.3, 83.3 and 166.6 mg/kg/day in single oral dose toxicity and 0, 4.2, 8.3, 41.7 and 83.3 mg/kg/day in repeated oral dose toxicity tests. Their blood and urine were assayed and organ morphology were examined. Mann-Whitney U test and ANOVA tests were used by analysing methods. First, significant increased left renal weight in all groups of EC and BC. Second, increased ALT score was found in EC-S2 and increased relative liver weight was found in EC-S3. In addition, increased relative weight and urine bilirubin and urobilinogen were found in EC-R2 and EC-R3. There was no significant toxic change in BC. The Mixture of EC had a possibility of hepatotoxicity in the short and long term. Processed BC appears to be safe and non-toxic in these studies and a no-observed adverse effect level (NOAEL) was established at 83.3 mg/kg/day in mice. Relatively, The BC were safer than The EC.

• Journal of the East Asian Society of Dietary Life
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• v.25 no.2
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• pp.309-315
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• 2015

This study aimed to develop and validate an analytical method for ethyl carbamate (EC) in Maesilju. For accurate analysis of EC in Maesilju, an internal standard (d5-EC) and neutralization (pH=7) were performed. The limit of quantification (LOQ) was 3.65 ppb while the recovery rate ranged from 92.54% to 103.59%. Intra- and inter-day precision ranged from 0.87% to 1.99% and 2.67% to 5.64%, respectively. Maesilju samples comprised 10 homemade and five commercial ones. Samples contained EC at levels between 118.48 and 2,640.42 ppb. The average content of homemade Maesilju was higher than those of commercial ones. Based on manufacturers' labeling of commercial samples and information on homemade samples, various factors such as ingredients and soaking time of Maesil affected EC level in Maesilju. EC contents showed a positive correlation with age of Maesilju.

• The Korean Journal of Food And Nutrition
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• v.31 no.6
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• pp.828-835
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• 2018

The objective of this study was to examine the biochemical parameters of hepatic function such as serum level of ALT (alanine aminotransferase), AST (aspartate aminotransferase), ALP (alkaline phosphatase), LDH (lactate dehydrogenase), and content of TG (triglyceride) and cholesterol, and tissue immunological changes of the $CCl_4$-treated rats with administration of the mixed sample extract (MSE). The liver weight in $CCl_4$-administered experimental control group (EC) was slightly higher than that of normal control (NC) group. Hepatic damage parameters (ALT, AST, ALP, LDH & TG) in serum of the EC group were significantly higher than those in serum of the NC and silymarin-treated positive control (PC) group. On the other hand, these hepatic damage parameters of MSE-treated experimental (E1 & E2) groups were significantly lower than those of EC group. The number of WBC, neutrophils, lymphocytes and platelets, and the contents of hemoglobin, and hematocrit in EC group were significantly higher than those of NC group. However, the number of WBC and lymphocytes in E1 and E2 groups were significantly lower than those of EC group. Also, the collagen developmental areas in the liver of NC and PC groups by hepatic immuno-histological findings were found slightly positive. Whereas, hepatic fibrous developmental tissue of EC group was strongly positive brown color band, those of E1 & E2 groups were decreased. Therefore, it was concluded that the induction of hepatic fibrous tissue activation had a preventive effect of MSE against the $CCl_4$-induced hepatic damage in rats. However, further study is needed in this filed.

• Korean Journal of Agricultural Science
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• v.46 no.1
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• pp.103-111
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• 2019

Gray mold caused by Botrytis cinerea on strawberry plants is an economically significant disease in Korea. The rates for diseased fruits are high during the strawberry harvesting period from December to February, especially in hydroponic cultivation. This study assessed the effect of the nitrogen type in the soil culture and the electrical conductivity (EC) of the nutrient solution in a hydroponic culture on the gray mold incidence in 'Seolhyang' strawberry plants. The nitrogen sources assayed included calcium nitrate tetrahydrate (CN4), calcium nitrate decahydrate (CN10), ammonium sulfate (AS), and commercial fertilizer 213 (213). The effect of the EC was tested at 0.5, 0.8, 1.0, and $1.5dS{\cdot}m^{-1}$. The occurrence of gray mold varied according to the nitrogen type. The disease incidence and nitrogen content for the main nitrogen type were higher compared to the non-treated control. The AS treatment showed the highest occurrence of tipburn and gray mold. The incidence of gray mold as well as the nitrogen and phosphorus content of the leaves increased as the EC level was increased. These results indicate that the incidence of gray mold in strawberry plants is related to the nitrogen content of the leaf and the EC of the nutrient solution.

• Journal of the Korean earth science society
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• v.43 no.4
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• pp.539-556
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• 2022

In the coastal areas of Jeju Island, composed of volcanic rocks, saltwater intrusion occurs due to excessive pumping and geological characteristics. Groundwater level and electrical conductivity (EC) in multi-depth monitoring wells in coastal areas were characterized from 2005 to 2019. During the period of the lowest monthly precipitation, from November 2017 until February 2018, groundwater level decreased by 0.32-0.91 m. During the period of the highest monthly precipitation, from September 2019 until October 2019, groundwater level increased by 0.46-2.95 m. Groundwater level fluctuation between the dry and wet seasons ranged from 0.79 to 3.73 m (average 1.82 m) in the eastern area, from 0.47 to 6.57 m (average 2.55 m) in the western area, from 0.77 to 8.59 m (average 3.53 m) in the southern area, and from 1.06 to 12.36 m (average 5.92 m) in the northern area. In 2013, when the area experienced decreased annual precipitation, at some monitoring wells in the western area, the groundwater level decreased due to excessive groundwater pumping and saltwater intrusion. Based on EC values of 10,000 ㎲/cm or more, saltwater intrusion from the coastline was 10.2 km in the eastern area, 4.1 km in the western area, 5.8 km in the southern area, and 5.7 km in the northern area. Autocorrelation analysis of groundwater level revealed that the arithmetic mean of delay time was 0.43 months in the eastern area, 0.87 months in the northern area, 10.93 months in the southern area, and 17.02 months in the western area. Although a few monitoring wells were strongly influenced by nearby pumping wells, the cross-correlation function of the groundwater level was the highest with precipitation in most wells. The seasonal autoregressive integrated moving average model indicated that the groundwater level will decrease in most wells in the western area and decrease or increase in different wells in the eastern area.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.6
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• pp.2625-2628
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• 2012

Introduction: Fumonisin B1 (FB1) is a toxic and carcinogenic mycotoxin produced in cereals due to fungal infection. This study was conducted to determine FB1 contamination of rice and corn samples and its relationship with the rate of esophageal cancer (EC) in a high risk area in northeastern Iran. Methods: In total, 66 rice and 66 corn samples were collected from 22 geographical subdivisions of Golestan province of Iran. The levels of FB1 were measured for each subdivision by thin layer and high pressure liquid chromatographies. The mean level of FB1 and the proportions of FB1 contaminated samples were compared between low and high EC-risk areas of the province. Results: The mean of FB1 levels in corn and rice samples were 223.64 and 21.59 ${\mu}g/g$, respectively. FB1 contamination was found in 50% and 40.9% of corn and rice samples, respectively. FB1 level was significantly higher in rice samples obtained from high EC-risk area (43.8 ${\mu}g/g$) than those obtained from low risk area (8.93 ${\mu}g/g$) (p-value=0.01). The proportion of FB1 contaminated rice samples was also significantly greater in high (75%) than low (21.4%) EC-risk areas (p-value=0.02). Conclusion: We found high levels of FB1 contamination in corn and rice samples from Golestan province of Iran, with a significant positive relationship between FB1 contamination in rice and the risk of EC. Therefore, fumonisin contamination in commonly used staple foods, especially rice, may be considered as a potential risk factor for EC in this high risk region.

• Journal of Bio-Environment Control
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• v.15 no.4
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• pp.396-399
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• 2006

This study was conducted to investigate the desalinizing effect of some vegetable crops (beet, crown daisy, kale, lettuce, spinach, sweet com, and tomato) in salinized soil. The soil was treated with highly concentrated nutrient solutions and the growth of these crops was compared and soil salinity was monitored. The plant height of lettuce and crown daisy inhibited severely in with EC $5dS{\cdot}m^{-1}$ salinized soil. Soil EC level was the lowest in soil where tomato was cultivated followed by corn and kale. The residual level of $NO_3$ was higher in soils used for cultivation of corn, tomato, and kale, that of K was higher in soils used for cultivation of corn, tomato, and beet, and That of $P_2O_5$ was higher in soils used for cultivation of corn and tomato. Although the desalinizing effect was greatest by tomato and corn after 60 days of cultivation. Quality of the these crops was low and the cultivation periods of these crops overlapped with that of the main crops. Kale, on the other hand showed less growth inhibition in salinized soil, greatest desalinating effect based on fresh weight. In addition this crop only needs 30 days of cultivation period. Therefore, kale was most efficient crop in desalinizing considering crop quality, a short cultivation period, and nonoverlapping cultivation time with the main crops.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.1
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• pp.18-25
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• 2014

This study was performed to develop the source profiles for fine particles ($PM_{2.5}$) emitted from the meat cooking. The characterization of fine particles emitted from beef cooking showed comparably high level of carbon (75%) which mainly composed of OC (73%) and EC (2.3%). Also the level of $K^+$, $Cl^-$, K, Cl, and $Na^+$ has been diagnosed to be relatively high, mainly caused by the Korean spice with sodium component. The cooking of pork showed similar trend to the beef, resulting high level of OC, EC, $K^+$, $Cl^-$, K, Cl, and $Na^+$ as the major components of fine particles. The high proportions of metal's ingredient such as Zn and Pb have been spotted to be 0.463% and 0.386%, respectively. The higher ratio of OC has been collected for raw pork belly meat compared to seasoned meat in respond to presence of fat. The cooking of chicken and duck brought similar data that OC, $K^+$, K, $Cl^-$, Cl, EC, $NO_3{^-}$, and $SO{_4}^{2-}$ were main components of fine particles. The one notable feature is that Zn and Pb showed to be almost absent.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.993-994
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• 2008

Electrochromic (EC) devices are capable of reversibly changing their optical properties upon charge injection and extraction induced by the external voltage. The characteristics of the EC device, such as low power consumption, high coloration efficiency, and memory effects under open circuit status, make them suitable for use in a variety of applications including smart windows and electronic papers. Coloration due to reduction or oxidation of redox chromophores can be used for EC devices (e-paper), but the switching time is slow (second level). Recently, with increasing demand for the low cost, lightweight flat panel display with paper-like readability (electronic paper), an EC display technology based on dye-modified $TiO_2$ nanoparticle electrode was developed. A well known organic dye molecule, viologen, was adsorbed on the surface of a mesoporous $TiO_2$ nanoparticle film to form the EC electrode. On the other hand, ZnO is a wide bandgap II-VI semiconductor which has been applied in many fields such as UV lasers, field effect transistors and transparent conductors. The bandgap of the bulk ZnO is about 3.37 eV, which is close to that of the $TiO_2$ (3.4 eV). As a traditional transparent conductor, ZnO has excellent electron transport properties, even in ZnO nanoparticle films. In the past few years, one-dimension (1D) nanostructures of ZnO have attracted extensive research interest. In particular, 1D ZnO nanowires renders much better electron transportation capability by providing a direct conduction path for electron transport and greatly reducing the number of grain boundaries. These unique advantages make ZnO nanowires a promising matrix electrode for EC dye molecule loading. ZnO nanowires grow vertically from the substrate and form a dense array (Fig. 1). The ZnO nanowires show regular hexagonal cross section and the average diameter of the ZnO nanowires is about 100 nm. The cross-section image of the ZnO nanowires array (Fig. 1) indicates that the length of the ZnO nanowires is about $6\;{\mu}m$. From one on/off cycle of the ZnO EC cell (Fig. 2). We can see that, the switching time of a ZnO nanowire electrode EC cell with an active area of $1\;{\times}\;1\;cm^2$ is 170 ms and 142 ms for coloration and bleaching, respectively. The coloration and bleaching time is faster compared to the $TiO_2$ mesoporous EC devices with both coloration and bleaching time of about 250 ms for a device with an active area of $2.5\;cm^2$. With further optimization, it is possible that the response time can reach ten(s) of millisecond, i.e. capable of displaying video. Fig. 3 shows a prototype with two different transmittance states. It can be seen that good contrast was obtained. The retention was at least a few hours for these prototypes. Being an oxide, ZnO is oxidation resistant, i.e. it is more durable for field emission cathode. ZnO nanotetropods were also applied to realize the first prototype triode field emission device, making use of scattered surface-conduction electrons for field emission (Fig. 4). The device has a high efficiency (field emitted electron to total electron ratio) of about 60%. With this high efficiency, we were able to fabricate some prototype displays (Fig. 5 showing some alphanumerical symbols). ZnO tetrapods have four legs, which guarantees that there is one leg always pointing upward, even using screen printing method to fabricate the cathode.