• Korean Journal of Environment and Ecology
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• v.32 no.4
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• pp.425-439
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• 2018

W investigated the environmental factors and inhabiting biota such as macrophytes and zooplankton in 43 sites located on Jeju Island from May and June 2017 to evaluate the spread and ecosystem risk of dotted duckweed (landoltia punctata) which was recently found for the first time in Jeju Island. Dotted duckweeds were found in a total of 18 sites which tended to show low biomass of aquatic macrophyte species other than the dotted duckweed. We conducted a pattern analysis using SOM (Self-Organizing Map), which extracts information through competitive and adaptive properties, to analyze the effect of inhabiting biota on aquatic macrophytes such as the dotted duckweed and environmental factors. The SOM analysis showed that the inhabiting biota such as the zooplankton affected the biomass of aquatic macrophytes than they did the environmental factors. In particular, the biomass of dotted duckweed was positively related to plant-attached species (Alona, Chydorus, and Pleuroxus). Considering that low density of aquatic macrophytes covers the streams and wetlands on Jeju Island because of irregular water source and sharp change of water depth, the dotted duckweeds are likely to play an essential role as the vital habitat for micro-biota including zooplankton in wetlands and streams on Jeju Island. Furthermore, considering that organic matters are utilized as the primary food source in the areas occupied by dotted duckweed, dotted duckweeds have the role of being both habitat and food source. Although the dense growth of dotted duckweed adversely affects growth and development of some aquatic plants due to the shadow effect, it is due to the dominance of floating plants on the water surface should not be regarded as the risk of the dotted duckweed. In conclusion, the dotted duckweeds have spread and settled in most of the water systems on Jeju Island, their impact on inhabiting biota and the aquatic environment was minor. It is necessary to monitor the distribution and spread of dotted duckweeds in the inland areas outside of Jeju Island in the future.

• Journal of Aquaculture
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• v.22 no.1
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• pp.42-50
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• 2009

Shrimp farming which is entirely conducted in outdoor ponds in the west coast of Korea has been suffered from mass mortality due to viral epizootics. Intensive indoor shrimp culture under limited water exchange can solve these problems of outdoor ponds including viral transmission from environment, pollution due to discharge of rearing water, low productivity and limited culture period. In this study, juvenile L. vannamei (B.W. 0.08-0.09 g) was stocked with $3,000-5,455/m^3$ in density in four raceway tanks (two $12.9\;m^2$, two $18\;m^2$ tanks) and cultured for 42 days with 2.7-3.4% of daily water exchange. Results from four tanks showed FCR of 0.79-1.29, survival of 38.2-48.0%, and yields of $2.49-4.22\;kg/m^3$ which is consistent with 12-20 and 8-14 times higher than those of commercial shrimp hatchery and outdoor pond in Korea, respectively. Concentrations of total ammonia nitrogen in all four tanks were 1.11-1.42 ppm in mean level and did not exceed 6.0 ppm (0.096 ppm of $NH_3$) which is still acceptable levels for shrimp growth. During the culture trial, concentration of $NO_2$-N rapidly increased from stocking, resulting in mean concentration of 18.45-22.07 ppm. It also exceeded 10 ppm over four weeks and maintained at 35-45 ppm for four days in all tanks, accounting for low survival of shrimp due to long-term exposure to high concentration of $NO_2$-N. Nevertheless, the results with survival rate over 38% from raceways which experienced the extreme $NO_2$-N levels suggests that under "biofloc system" white shrimp can acclimate to high $NO_2$-N concentration to some degree.

• Korean Journal of Environment and Ecology
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• v.28 no.6
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• pp.657-663
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• 2014

This study was conducted to investigate the difference in feeding habits of Red-Tongued Viper Snakes, according to available foods sources and areas. The effects of differences in food sources were found on Red-Tongued Viper Snake inhabited in the Jeju Island and its islet Gapado, from May 2006 to Nov. 2010. The food sources for the Red-Tongued viper snake population in the Jeju Island were found to be as follows: Chinese red-headed centipedes (Scolopendra subspinipes mutilans), Jeju Salamanders (Hynobius quelpaertensis), Japanese tree Frogs (Hyla japonica), Narrow-mouthed Toad (Kaloula borealis), Dybowski's Brown Frogs (Rana dybowskii), Black-spotted Pond Frogs (Rana nigromaculata), Smooth Skinks (Scincella vandenburghi), Asian Keelback Snakes (Amphiesma vibakari), Lesser White-toothed Shrews (Crosidura shantungensis), Hallasan Shrews (Sorex caecutiens hallamontanus), and Jeju Striped Field Mice (Apodemus chejuensis). This implies that Red-Tongued Viper Snakes mainly feed on amphibians, reptiles, and small mammals. Among these, amphibians occupied the highest portion at 55.2% followed by mammals at 20.7%, centipedes at 13.8%, and reptiles at 10.3%. On the contrary, Red-tongued viper snake population in Gapado only feed on Chinese red-headed centipedes and Smooth Skinks (S. vandenburghi). Since only a small amount of nutrient can be obtained from Chinese red-headed centipeds or Smooth Skinks, this feeding habit for Red-tongued viper snake would adversely effect on the growth or regeneration. The reason why Red-Tongued viper snake population in the Gapado mainly feed on Lizard and Centipedes in spite of relatively various available food sources, might be due to the low density of other food sources in the Gapado. Red-Tongued viper snake could be feeding on foods that are low in quality but are easily accessible, to minimize energy consumption on searching for other more nutritious foods. A snake tends to select the size of its food depending on the size of its own head. The positive correlation was found between the size of the heads of Red-Tongued viper snakes from the Jeju island and the diameter of their foods. The head size was larger in the males than females in viper snake population from the Jeju Island, which might effect on their selection of foods. However, no significant difference was found between the sizes of the head and the food in the Red-Tongued viper snake population from the Gapado. The findings of this study would provide meaningful data, which directly shows that even within the same viper species they choose different available food sources according to their inhabitance. This leads to their growth and adaptation to their environment which is beneficial for sustaining of its population.

• Korean Journal of Agricultural Science
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• v.41 no.3
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• pp.213-220
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• 2014

This study was conducted to evaluate the effects of high n-3 or n-6 diet on free fatty acid profile and meat quality traits of pork loin. The 20 heads of commercial $Landrace{\times}Yorkshire{\times}Duroc(LYD)$ crossbreed pigs ($90.9{\pm}2.4BWkg$) were divided into four groups by added fat and oils, such as 5% tallow (Control), 5% linseed oil (T1), 5% safflower oil (T2), and mixture of linseed oil (2.5%) + safflower oil (2.5%) (T3), then reared 4 weeks. Pork loins were taken after slaughter, then sliced in 2 cm thickness and put in low-density polyethylene (LDPE) bag for analysis. T1 showed significantly high concentration of linolenic acid ($2.35{\pm}0.21%$) (p<0.05). The total amount of saturated fatty acids (SFA), mono-unsaturated fatty acids (MUFA) and poly-unsaturated fatty acid (PUFA) was significantly high in T1 ($36.05{\pm}1.18%$), C ($22.60{\pm}2.11%$) and T2 ($47.80{\pm}1.29%$), respectively (p<0.05). However, the ratio of n-6:n-3 was significantly low in T1 ($11.57{\pm}0.90$) than that of T2 ($37.56{\pm}12.51$) (p<0.05). There was no signigicant difference in lightness, redness, pH, water holding capacity and cooking loss between treatments (p>0.05). However, the yellowness of T2 was significantly higher than others (p<0.05). From those results, it was considered that feeding high n-3 and n-6 fatty acid diet to pig enables modify fatty acid profile of pork without any side effect on meat quality.

• Economic and Environmental Geology
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• v.44 no.6
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• pp.493-502
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• 2011

We study the deep structure of Korean Peninsula by estimating Moho depth and crustal thickness from using land and oceanic topography and free-air gravity anomaly data. Based on Airy-Heiskanen isostatic hypothesis, the correlated components between the terrain gravity effects and free-air gravity anomalies by wavenumber correlation analysis(WCA) are extracted to estimate the gravity effects that will be resulted from isostatic compensation for the area. With the resulting compensated gravity estimates, Moho depth that is a subsurface between the crust and mantle is estimated by the inversion in an iterative method with the constraints of 20 seismic depth estimates by the receiver function analysis, to minimize the uncertainty of non-uniqueness. Consequently, the average of the resulting crustal thickness estimate of Korean Peninsula is 32.15 km and the standard deviation is 3.12 km. Moho depth of South Korea estimated from this study is compared with the ones from the previous studies, showing they are approximately consistent. And the aspects of Moho undulation from the respective study are in common deep along Taebaek Mountains and Sobaek Mountains and low depth in Gyeongsang Basin relatively. Also, it is discussed that the terrain decorrelated free-air gravity anomalies inferring from the intracrustal characteristics of the crust are compared to the heat flow distributions of South Korea. The low-frequency components of terrain decorrelated Free-air gravity anomalies are highly correlated with the heat flow data, especially in the area of Gyeongsang basin where high heat flow causes to decrease the density of the rocks in the lower crust resulting in lowering the Moho depth by compensation. This result confirms that the high heat sources in this area coming from the upper mantle by Kim et al. (2008).

• Journal of Life Science
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• v.17 no.12
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• pp.1701-1708
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• 2007

Seed pelleting is generally conducted in order to save the labor for sowing and thinning by enabling the precision mechanical planting. In the present study, the influence of physical and chemical properties of pelleting solid materials was investigated on carrot seed germination. Among the pelleting solid materials evaluated, dialite, kaolin, and talc showed low bulk density and high porosity. Bentonite and dialite carried high water holding capacities of 184% and 173%, respectively, while calcium carbonate, calcium oxide, and fly ash showed relatively low water holding capacity. The pH of kaolin (6.8) and dialite (7.4) were close to neutral, while limestone (12.8), calcium oxide (13.0), and bentonite (10.0) were highly basic. High electro-conductivity was shown in limestone and calcium oxide. EDS analysis revealed that the main elemental compositions of talc were Si (71.0%) and Mg (29.0%), and those of calcium carbonate were Ca (66.6%), Si (22.9%), and Mg (10.5%). High granulation capacity was observed from talc and the mixture of talc and calcium carbonate. Seeds pelleted with bentonite showed the highest hardness. The dissolving type of the pellet layer after imbibition was split type in talc, limestone, zeolite, and fly ash, melt type in calcium carbonate and calcium oxide, and swell type in bentonite and vermiculite. The shortest dissolving time of pellet layer was observed from calcium carbonate and kaolin. The germination speed $(T_{50})$ was delayed as the size of pelleted seeds increased. The optimum size of pelleting was 19 ratio in carrot.

• Journal of Genetic Medicine
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• v.7 no.2
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• pp.138-144
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• 2010

Purpose: Endothelial progenitor cells (EPCs), which mediates neovascularization of uterine endometrium may be involved in the neovascularization in the utero-placental circulation. Low numbers of endothelial progenitor colony-forming unit (CFU) in culture are predictive biomarker of vascular disease. The aim of the present study was to evaluate whether the number of CFU in preeclampsia differed from that in normal pregnancy. Materials and Methods: Women with singleton normal (n=26) or preeclamptic (n=20) pregnancies were studied during the third trimester. The number of EPCs was quantified by CFU methodology. Plasma levels of angiogenic factors, vascular endothelial growth factor (VEGF), soluble fms-like tyrosine kinase-1 (sFlt-1), and placental growth factor (PlGF) were determined by enzyme-linked immunoassay. Results: CFU numbers were significantly decreased in the preeclamptic patients compared with the controls (median, 3; range 1-12 vs. 31; 3-81 CFU/well, P<0.001). A majority of the cells comprising individual colonies were positive for endothelial characteristics (Ulex europaeus lectin staining and acetylated low-density lipoprotein uptake). Plasma levels of the sFlt-1 were highly elevated (P<0.001) in patient with preeclampsia compared to controls, whereas PlGF were highly reduced (P=0.004), but these factors did not associate with CFU numbers. Conclusion: Our results suggest that reduced numbers of CFU obtained from maternal peripheral blood may contribute to the development of preeclampsia.

• Journal of Food Hygiene and Safety
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• v.21 no.4
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• pp.213-217
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• 2006

The halophilic bacterium Vibrio vulnificus is known to be a foodborne pathogen that causes septicemia in human. V. vulnificus infection is characterized by the high fatality rates and the primary attack against a person who have underlying diseases such as liver cirrhosis. However, there is no effective treatment for V. vulnificus septicemia except for classical treatments such as antibiotics. Recently, it has been known that lipoprotein (LDL) plays a major role in the protection against infection and inflammation. Consequently in this paper we analyzed the effects of LDL on V. vulnificus septicemia. We purified V. vulnificus cytolysin, a major virulent factor of V. vulnificus infection and measured inhibitory effects of mouse serum, cholesterol, and LDL on its hemolytic activity. Next experiments were performed to investigate whether LDL has a protective role against septicemia induced by V. vulnificus in mice. Intraperitoneal injection of LDL (1mg as protein) into mice 3hr before V. vulnificus $(1\times10^6\;CFU)$ injection, and V. vulnificus -induced lethality was determined. For the determination the relationship between LDL or cholesterol and prognosis, we determined serum levels of cholesterol and lipoprotein from V. vulnificus septicemia patients (n=15) who had visited the Chonbuk National University Hospital in Chonju. V. vulnificus cytolysin -induced hemolysis of mice erythrocytes was completely inhibited by serum, cholesterol, and low-density lipoprotein. V. vulnificus- induced lethality of mice injected with LDL showed only 40% compared to 100% of control. In survival groups (n=4) of V. vulnificus septicemia patients (n=15), their serum LDL and cholesterol revealed normal levels ($153.3{\pm}40.7,\;LDL;\;190.8{\pm}16.3$, Total cholesterol). However, in death groups (n=11) showed very low levels ($35.6{\pm}13.9,\;LDL;\;59.2{\pm}15.1$, Total cholesterol). Our study indicates that cholesterol and LDL are a prognosis indicator of V. vulnificus septicemia as well as an inhibitor of virulent action of V. vulnificus cytolysin. We suggested that the serum levels of cholesterol or LDL would be major index in the treatment and prevention of V. vulnificus septicemia.

• Journal of Nutrition and Health
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• v.17 no.2
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• pp.113-125
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• 1984

The long-term effects of vegetable and animal high fat diet on the lipid metabolism were investigated in male weaning rats. The rats were fed one of four semipurified diet ad libitum : control diet supplied 12% of calories as fat(control group), low fat diet supplied 3% of calories as fat(3% F group), 45% corn oil diet supplied 45% calories from corn oil(45% C group) and 45% butter fat diet supplied 45% calories from butte. fat(45% B group). The weights of liver, content of triacylglycerol(TG), total cholesterol and phospholipid(PL) in liver were investigated. The weight of liver of rats, fed 45% corn oil at 12 weeks and fed 45% butter fat for all period of diet were higher than that of control group. The contents of TG in liver of rats, fed 45% corn oil from 8 weeks and fed 45% butter fat for all period of diet were higher than that of control group. The levels of TG in liver of rats fed 45% butter fat were higher than those of rats fed 45% corn oil. The contents of total lipid and cholesterol in liver of rats were increased with similar trend of TG level, but contents of PL in liver had no relation with the levels and types of dietary fat and feeding periods. The liver of rats were observed histochemically by light microscope. Mild to severe level of fatty changes in liver of 45% C and 45% B group were observed at 8 and 12 weeks of diet. The liver of rats in control group appeared to be healthy and normal electron-microscopically, but in fatty degenerated hepatocytes of 45% C and 45% B group, nuclear membranes were irregular and a great number of intracytoplasmic fat vacuoles in cells were variable in size and low in electon density. The numbers of lysosome were increased and secondary lysosomes among them were observed on electron microscope.

• Journal of The Geomorphological Association of Korea
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• v.19 no.2
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• pp.99-111
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• 2012

The purpose of this study is to identify the change of geographical (or geomorphological) location environment of the dwelling site and its cause in Daejon Basin during transition from the Bronze Age to the Proto Three Kingdoms Period. In order to achieve this goal, it was divided into (1) 'comparison of the total number of dwelling sites of a group of remains (or high-density dwelling remains)' and (2) 'comparison of the total number of dwelling sites in certain remains including locations of dwelling of two periods' and location environment was compared to each other in aspects of altitude, gradient, 'distance from the river of water available for use' and 'the difference between the highest altitude and lowest altitude of river bed of water available for use' based on change of period. The results were as follows: 1. looking at a change of individual factors, the altitude was elevated and the gradient was increased. The distance from the river of water available for use was decreased or increased in case of 'small scale river' and it was very little difference or increased in case of 'medium scale river'. The difference between the highest altitude and lowest altitude of river bed of water available for use was increased in case of 'small scale river' and it was increased or decreased in case of 'medium scale river'. If comparing the individual factors to each other, the increase and decrease of altitude, gradient and the difference between the highest altitude and lowest altitude of river bed of water available for use have the similar pattern. Especially, it was shown that the increase of gradient affected the increase of altitude and the difference between the highest altitude and lowest altitude of river bed of water available for use. In addition, it was shown that the increase and decrease of distance from the river of water available for use had the different pattern from those of altitude, gradient and 'the difference between the highest altitude and lowest altitude of river bed of water available for use'. 3. With above results, it was thought that combination of micro landform characteristics (eg. Characteristics of gradient) of low hills distributed within Daejeon Basin and rich aquatic environment surrounding the low hills affected the selection of location of dwelling sites at the time. Especially, it was shown that 'gradient and distance from the river of water available for use' were relatively more important factors for the inhabitants at the time to select the location of dwelling sites compared to 'altitude and difference between the highest altitude and lowest altitude of river bed of water available for use' upon selecting the location of dwelling.