• Current Research on Agriculture and Life Sciences
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• v.29
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• pp.83-89
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• 2011

Various functional and useful components in Portulaca oleracea were extracted with ethanol and the optimum solvent conditions were set by monitoring of response surface methodology(RSM). A central composite design for optimization was applied to investigate the effects of the three independent variables of extraction temperature, ethanol concentration, and extraction time, on dependent variables including total phenolics, electron-donating ability, brown clolor and total flavonoids of Portulaca oleracea. The content of total phenol was essentially unaffected by extraction time or extraction temperature, but it was highly influenced by ethanol concentration. The maximum total phenol content was 31.70mg/mL obtained at 45.84% of ethanol concentration, $79.66^{\circ}C$, and after 2.67hr of extraction. Electron-donating ability (EDA) was affected by ethanol concentration and the maximum EDA was 74.67mg/mL at 52.95% ethanol concentration, $52.33^{\circ}C$ and 4.84hr of extration time. The browning color was rarely affected by extraction time but, it was highly influenced by ethanol concentration and extraction temperature. The maximum extent of browning color was obtained at 97.75% of ethanol concentraion, $65.88^{\circ}C$ and 2.93hr of extraction time. The content of total flavonoid was significantly influenced by extraction time, and the maximum total flavonoid level was 58.28mg/mL obtained at 96.62% ethanol concentration, $61.87^{\circ}C$ after 3.70hr of extraction. As a result, The optimal conditions for effective extraction were predicted as follows, 70.3% of ethanol concentration, $62.1^{\circ}C$ of extraction temperature and 3.3hr of extraction time.

• Journal of Bio-Environment Control
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• v.13 no.4
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• pp.233-239
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• 2004

This research was conducted to determine the effect of soil pH change followed by leaching with ground water on crop growth, yield and nutrient uptake of strawberry. Treatments were leaching with ground water (A), hydrated lime application of dissolved portion in $500g{\cdot}L^{-1}$ solution followed by leaching (B), application of $Al_2SO_4$ solution with the concentration of $0.75g{\cdot}L^{-1}$ followed by leaching (C), pH elevation by (B) followed by pH lowering by (C), then leaching (D). Soil samples taken before experiment had 6.0 in soil pH. But the pH of all treatments taken after pH changes and leaching were in the range from 5.8 to 6.2 without statistical differences among treatments. Electrical conductivity of soils taken before experiment was $1.82dS{\cdot}m^{-1}$ and those of (A), (B), (C), and (D) were 1.65, 1.72, 1.71 and $1.83dS{\cdot}m^{-1}$, respectively. The plant height in treatment (C) was 20.4 cm at 80 days after transplanting which was the highest among treatments tested. The other growth characteristics did not show statistical differences among treatments. Tissue contents of Fe, Mn, Zn, Cu and B in treatment (C) were higher than those of other treatments at 80 days after transplanting. The treatment (C) had the highest number of special sizes and fruit weight per 50 plants such as 137 and 3.784 g, respectively. The treatment also had 3.123 kg in total fruit weight and 2,489 kg in marketable fruit weight per 10 are. The treatment (B) also had good results such as 2,820 kg in marketable fruit weight per 10 are.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.209-216
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• 2010

This study was to find out optimum rice cultivars for organic farming in no-tillage paddy. A field research was conducted the yield, yield components, and qualities of thirty two Korean rice cultivars, and two Japanese rice cultivars. The column length of early rice plant was shorter in medium maturing rice cultivars compared to early, and medium-late maturing rice cultivars. Planthopper population per20-plant was lower in Ilpumbyeo, Dongjinbyeo, Hojinbyeo, Donganbyeo, and Sobeebyeo in that order while was higherin rice cultivars of early maturity. The disease severity of sheath blight was higher in Saechucheongbyeo>Chucheongbyeo>Namwonbyeo>Sangmibyeo in that order, on the other hand, that was lowerinHwaseongbyeo>Junambyeo>Saesangjubyeo=Hitomebore>Ilpumbyeo>Hwayeongbyeo in that order, respectively. The grain yield of Korean rice cultivars was significantly higher in 2.95 Mg $ha^{-1}$ for Hwasinbyeo, 2.91 Mg $ha^{-1}$ for Ilpumbyeo, 2.86 Mg $ha^{-1}$ for Sobeebyeo, 2.73 Mg $ha^{-1}$ for Naepungbyeo, and 2.70 Mg $ha^{-1}$ for Saegyehwabyeo compared with 1.38 Mg $ha^{-1}$ for Hwabongbyeo, 1.62 Mg $ha^{-1}$ for Hwayeongbyeo, and 1.78 Mg $ha^{-1}$ for Haepyeongbyeo of medium maturing rice cultivars, respectively. Toyo taste value of medium maturing rice cultivars tended to higher than that of early, and medium-late maturing rice cultivars. Ripening rate of rice cultivars was significantly positive correlated with Toyo taste value while negative correlated with protein content. According to principal component analysis, these results show that Sangmibyeo, Sangsanbyeo, and Odaebyeo for early maturity, Naepungbyeo, and Sobeebyeo for medium maturity, and Hwasinbyeo, Chucheongbyeo, and Sindongjinbyeo for medium-late maturity were optimum rice cultivars for organic farming in no-tillage paddy.

• Horticultural Science & Technology
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• v.28 no.6
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• pp.980-984
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• 2010

Research regarding respiration rate, off-flavor related material and freshness maintenance effect of active MA mini-packaging on perilla leaves has been carried in this study. Respiration rate was highly maintained at high oxygen treatments ($CO_2:O_2:N_2$=0:30:70 and 0:50:50), higher than non-treatment and low oxygen treatments (6:2:92, 0:10:90) during the storage period, and ethylene production was relatively higher. However, off-flavor related materials, acetaldehyde and ethanol production was noticeably low. Weight losses of non-treatment and low-oxygen treatment were about 1.8 and 1.4%, respectively. At the fifth day of storage there was no weight loss. Ascorbic acid content was 13.3 mg/100 g F.W. at the first day of storage. At the third day of storage non-treatment showed the lowest value of ascorbic acid, 8.8 mg/100 g F.W. Ascorbic acid content of active MA treatment gradually decreased without a striking difference as the storage day extended. Chlorophyll content was the lowest at the fifth day of storage with non-treatment, 47.5 (SPAD-502 unit) while the active MA treatment maintained high level of chlorophyll content, 53.0. Sensory evaluation (vision) showed that marketability gradually decreased but was maintained in high oxygen treatments (0:30:70 and 0:50:50), even at the fifth day of storage. Occurrence of off-flavor in non-treatment at the fifth day of storage was extremely low, 2.6; whereas high in high oxygen treatment, 3.4. Active MA packaging maintained freshness two more days at room temperature (about $27^{\circ}C$).

• Journal of Chest Surgery
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• v.29 no.4
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• pp.373-380
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• 1996

Prevention of thromboembolism is the most important task in the development of bioconpatible small caliber artificial vascular graft. In normal vessels, vascular endothelial cells maintain homeosatsis by secreting numerous factors. The aim of this study is to develope a method which Improves biocompatibility of small caliver polyurethane graft using endothelial cell culture technique, and ev luate the efTectiveness of extracelluar matrix for endothelization which was produced by cultured fibroblast. Methods ; Multiporous polyurethane tube of 3 mm diameter, 0.3 mm thickness was manufactured for vascular graft. Three mongrel dogs were intubated and internal jugular veins removed. Extracelluar matrix produced by cultured flbrobast which was obtained from dog's internal jugular vein were coated to the polyurethane graft. Then, endothelial cells extracted from Jugular vein were cultured and fixed on the extracelluar matrix layer of vascular graft. Endothelial cell coated vascular grafts were implanted to the carotid arteries of experimental dogs as interposed autograft. Implanted grafts were removed after 3 and 6 weeks. As a control, PTFE graft was interposed on carotid artery. These experiments demonstrated that extracelluar matrix produced by fibroblast can afford a base for endothelial cell linings of polyurethane graft. Although thrombosis were developed on autografted en othelial cell coated graft, 33% opening was noticed, and showed less adhesion to adjacent tissue layer. These findings suggest that fiboblast produced extracelluar matrix which can be used for edothelial cell lining vascular graft, and by improving the cultured endothelial cell function, there will be a new modality for reducing thrombosis on small vascular graft.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.2
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• pp.228-238
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• 2007

This study was conducted to increase sweetpotato utilization and to determine the vegetative value of sweetpotato tips by investigating the phenolic compounds, antioxidative effect in oil, electron donating ability, nitrite scavenging effect and ACE inhibition activities. The phenolic compounds present in sweetpotato tips are the gallic, chlorogenic, gentisic, caffeic, couramic and ferulic acid, which are 16-122 times higher compared to other vegetables such as spinach, soybean sprout, and perilla leaves. In each solvent extract, the total phenolic compounds (175.8mg/g) was composed of 55% EtOAc extraction and 39% BuOH extract, respectively. The results of induction period using the Rancimat method showed that the antioxidant activity of SP tips was higher than the tocopherol or BHT. The relative levels of each solvent extract in SP tips were as follows: EtOAc>BHT>BuOH>Tocopherol>Water>$CHCl_3$>Hexane. The peroxide value was measured every 5 days for 25 days during storage and results showed that the peroxide value, the tips, tuberous root and tocopherol were lower compared to spinach, soybean sprout and perilla leaves. Nitrite scavenging effects were excellent in sweetpotato tips, perilla leaves and soybean sprout, especially, inhibition rate of perilla leaves (72%) were superior to the others. In process of solvent extraction, activity of BuOH and water extractions were the best. ACE inhibition activity in sweetpotato tips was 1.5 times higher than in tuberous roots and $1.9{\sim}3.7$ times higher than in spinach, soybean sprout, perilla leaves.

• Korean Journal of Environmental Agriculture
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• v.12 no.2
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• pp.153-161
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• 1993

This study was conducted to compare the resistance and sensitivity of trees with 6 native species exposing to 4 different levels of $SO_2$gas(0.4, 0.7, 1.5 and 3.0 ppm) respectively. The results are summarized as follows : 1. Visible injuries appeared as spots in the region of intervein on the leaves for all the species and the color of the spots changed from light green and/or brown to light brown, dark brown, and/or redish brown. 2. The sensitivity of the species to $SO_2$ was high in the descending order of Zizyphus jujuba, Cataegus pinnatifida, Viburnum sargentii, Weigela subsessilis, Euonymus japonica, and Acer ginnala. 3. The resistance of the species to $SO_2$ was high in the descending order of Acer ginnala, Eunymus japonica Viburnum sargentii, Weigela subsessilis, Zizyphus jujuba, and Crataegus pinnatifida. 4. When the trees were exposed to $SO_2$gas, the contents of chlorophyll a, b, and a+b were consostently lower than those of control, and water soluble sulfur contents in the leaves were higher than those of control. 5. There was no significant correlation between stomatal resistance and the sensitivity(or resistance) of the trees exposed to $SO_2$ gas. 6. In this study, it was concluded that Acer ginnala was more suitable species than the others for landscape in air polluted area because it showed high resistance, low sensitivity, and low stromal resistance to $SO_2$gas exposure.

• Journal of Animal Science and Technology
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• v.44 no.1
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• pp.123-134
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• 2002

An experiment was conducted to establish the most suitable ventilation system for the enclosed nursery pig house in Korea, comparing four different ventilation systems ; i) air enters through perforated ceiling and exhausts through chimney (NA), ii) air enters through perforated ceiling and exhausts through side walls (NB), iii) air enters through perforated ducts and exhausts through side walls (NC) and iv) air enters through perforated ducts and exhausts through chimney(ND). The experiment was carried out during winter and summer separately. The experimental pigs were weaned at fourteen days old in winter (December-February) and at twenty one days old in summer (June-August). The main results of the experiment are as follows : A preliminary experiment showed that in the NC system during summer, air can reach all the pig rooms in the house and the air flow rates of the upper, middle (1.2 m height of the room) and low (at the height of pig stature) parts of the room were measured at 7.0-8.08, over 0.5 and over 0.2 m/s, respectively, which flow rates were much higher(p$<$0.05) than those in other system. At the minimum ventilation efficiency during winter, air flow rates of upper, middle and low parts of the room equipped with the NC system were detected at over 1, less than 0.5 and around 0.07 m/s, respectively. It is concluded that the separated ventilation system air-entering through ducts is the most suitable for the ventilation system of the enclosed nursery pig house and the exhausting system through side walls is more efficient for ventilation than the system through roof. Furthermore, to sustain proper temperature and reduce energy waste as well as heat consumption, a future research should be carried out to develop the environmental control system in relation to developing a heat regulator.

• Current Research on Agriculture and Life Sciences
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• v.3
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• pp.28-35
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• 1985

This work Was carried out to obtain the most suitable crop coefficient for the paddy rice growing in Taegu area. The result was due to the comparative measurements of evapotranspiration formula in terms of Blaney & Criddle and eight other formulas with those produced by experiment particularly in this area. The crop coefficient, evapotranspiration and transpiration ratio produced by this research are hopefully expected to be of service in the future calculation of evapotranspiration without repeating experiment respectively, whenever the water requirement of paddy rice is planned in Taegu and its vicinity. The accomplished results could be summarized as follows : The maximum amount of evapotranspiration was recorded in the early and middle parts of August. The average reading of evapotranspiration was 6.33mm/day throughout the growth. The evapotranspiration had a highly significant correlation with pan evaporation, solar radiation, sunshine hours and relative humidity of meteorological elements. K and Kc by the use of Blaney & Criddle formula calculated at 0.76 to 1.45 and 0.82 to 1.27, respectively. Its peak value appeared commonly in early August. The ratio of transpiration was 269.03.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.4
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• pp.342-346
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• 1996

Field experiments were conducted to investigate the mode of changes in exchangeable K contents in the soil under the continued(for three years) application of different levels of K fertilizer(KCl) with and without application of conventional compost(CC) and chicken-dung derived compost (CDC) for red pepper cultivation at two field parcels with different exchageable K contents on Gopyong silty loamy soil. The application of KCl at standard rate for red-pepper resulted in the increase in exchangeable K in the soil after each harvest of the crop. while no application of K and the application of KCl at one half of the standard rate tended to lower the exchangeable K in top soil with the cultivation of the crop. The application of compost in addition to KCl ammplified the difference in exchangeable K in the soil before and after the harvest of each crop. An equation could resonably well predict the exchageable K content in top soil after the years of crop cultivation, under different treatments. were developed.