• Journal of the Korean Applied Science and Technology
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• v.34 no.2
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• pp.236-243
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• 2017

In the present study, 70% ethanol extract, the ethyl acetate fraction were prepared from citron (Citrus junos)seed and their antioxidative ability was evaluated. The yields of extract and fractions were 5.1 and 0.9% per dried powder, respectively. In the 1,1-Phenyl-2-picrylhydrazyl (DPPH) radical test, free radical scavenging activities ($FSC_{50}$) of 70 % ethanol extract, ethyl acetate fraction were 512.1 and $514.0{\mu}g/mL$, respectively. Evaluation of total antioxidant capacities ($OSC_{50}$) using $Fe^{3+}$-EDTA system. Their $OSC_{50}$ of ethyl acetate fraction were $86.5{\mu}g/mL$. this antioxidant capacities higher than that of 70% ethanol extract. but lower than that of L-ascorbic acid ($1.72{\mu}g/mL$), known as a prominent water soluble antioxidant. The cellular protective effects on the $^1O_2$-induced cellular damage of rabbit erythrocytes were evaluated and the results showed that the extract was lower than (+)-${\alpha}$-tocopherol and low concentration of ethyl acetate fraction was similar to (+)-${\alpha}$-tocopherol. but not at high concentrations of ethtyl acetate fraction. it was able to induce cellular damage at high concentration.

• Journal of the Korean Applied Science and Technology
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• v.9 no.2
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• pp.175-179
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• 1992

In order to investigate the effect of tannic acid and ${\alpha}$-tocopherol on methyl linoleate autoxidation and on inhibition activity of lipoxygenase in phospholipid, the rate of formation of methyl linoleate hydroperoxide was measured by HPLC. The reaction mixture contained methyl linoleate 70mM, radical initiator AMVN 0.7mM, tannic acid and ${\alpha}$-tocopherol 0.7mM, each, in a mixture of hexane/isopropanol(1 : 1, v/v). Under this reaction condition, tannic acid was good enough antioxidant. The tannic acid and ${\alpha}$-tocopherol for the inhibition activivity of lipoxygenase were measured at the reaction conditions: phospholipid $1{\mu}M$. tannic acid and ${\alpha}$-tocopherol were reacted as an inhibitor of lipoxygenase in phospholipid, especialy in phosphatidy lcholine.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.1
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• pp.22-27
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• 2005

To find out the optimum mixture ratio of ammonium and nitrate on rice plant, 4 rice varieties were examined during 14days after transplanting in hydroponics with the different ratio of ammonium to nitrate(100 : 0, 75: 25,50: 50, 25: 75 and 0: 100). The highest N uptake from solution and the maximum plant dry weight were $60\~70\%$ ammonium and $30\~40\%$ nitrate mixture treatment both in Japonica and Tongil type rice plants. And with the same varieties N-uptake and N use-efficiency were compared between 10.0 mM and 1.0 mM nitrogen using $70\%$ ammonium and $30\%$ nitrate for 24 days after transplanting. Rice plants absorbed more nitrogen$(131\~145\%)$ in 10.0mM than 1.0mM treatment but accumulated N in rice plants were almost the same in both treatment. Among the tested rice cultivars, dry matter production and total accumulative nitrogen in rice plants were much high in Tongil type than japonica type rice cultivars. N-recovery ratios of rice plants from uptake N were $90.8-99.0\%$ in low concentration N solution(1.0 mM), but $69.4-81.7\%$ were observed in high concentration N solution(10.0 mM). It means that suppling low concentration N steadily will be better to prevent loss of N without reducing of growth in rice plants.

• The Journal of Engineering Geology
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• v.15 no.3
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• pp.303-307
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• 2005

Severe drawdown of Groundwater level(CWL) is observed from the analysis of the relationship between precipitation and CWL data during dry seasons in Ssangchun watershed. For Ssangchun watershed, the correlation was the strongest when we apply 70 day Moving Average(MA) for Groundwater dam Operation Index(COI) calculation. To determine the critical infiltration, which is the spatially averaged maximum daily infiltration, a certain value is fixed as the maximum infiltration and precipitation data is modified. COI is recalculated after the data modification and the correlation between COI and GWL is checked. The critical infiltration is determined when the best correlation is obtained after we repeat the above procedure with different fixed values. The critical infiltration is 40m for Ssangchun watershed. The correlation between CWL and COI is higher when we consider critical infiltration than we neglected it.

• The Korea Journal of Herbology
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• v.31 no.3
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• pp.43-48
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• 2016

Objectives : The objective of this research was to investigate the antioxidant activities of stem bark of Maackia amurensis extract.Methods : Stem bark of Maackia amurensis extract were prepared using 70% methanol. Methanol extracts were fractionated to hexane, chloroform, ethyl acetate, butyl alcohol, water fractions and investigated. The antioxidant activities of fractions was evaluated by four different assays as total polyphenol contents, total flavonoid contents, DPPH(1,1-diphenyl-2-picrylhydrazyl) free-radical scavenging activity and ABTS(2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) scavenging ability.Results : The yield of methanolic extracts from stem bark of Maackia amurensis was 10.16%, whereas those of its solvent fractions (hexane, chloroform, ethyl acetate, butyl alcohol, and water) were 5.45, 11.39, 13.88, 26.07, and 40.80%, respectively. The total polyphenol contents and electron donating ability of 70% methanol extracts from stem bark of Maackia amurensis were 15.44 mg/g and 194.15 μg/mL of its IC₅₀, respectively. The 70% methanol extracts showed the highest antioxidant activity. The total polyphenol content and total flavonoid content of chloroform fractions were higher in each of 201.98 mg/g and 13.55 mg/g. The chloroform fraction showed the lowest levels of DPPH(IC₅₀, 183.95 μg/mL) and ABTS scavenging activity(IC₅₀, 10.0 μg/mL). The antioxidant activity was detected in methanol extract, chloroform fractions.Conclusions : These results indicate that 70% methanol extract and its fractions of stem bark of Maackia amurensis, especially chloroform fraction, have the properties of anti-oxidant suggesting stem bark of Maackia amurensis may be a candidate for natural and functional materials.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.4
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• pp.323-330
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• 2004

Estrogen may promote osteoblast/osteocyte viability by limiting apoptotic cell death. We hypothesize that hsp27 is an estrogen- regulated protein that can promote osteoblast viability by increasing osteoblast resistance to apoptosis. The purpose of this study was to determine the effect of estrogen treatment and heat shock on $TNF{\alpha}$ - induced apoptosis in the MC3T3-E1 cell line. Cells were treated with 0 - 100 nM $17{\beta}$ estradiol (or ICI 182780) for 0 - 24 hours before heat shock. After recovery, apoptosis was induced by treatment with 0 - 10 ng/ml TNF${\alpha}$. Hsp levels were evaluated by Northern and Western analysis using hsp27, hsp47, hsp70c and hsp70i - specific reagents. Apoptosis was revealed by in situ labeling with Terminal Deoxyribonucleotide Transferase (TUNEL). A 5 - fold increase in hsp27 protein and mRNA was noted after 5 hours of treatment with 10 - 20 nM $17{\beta}$ estradiol prior to heat shock. Increased abundance of hsp47, hsp70c or hsp70i was not observed. TUNEL indicated that estrogen treatment also reduced (50%) MC3T3-E1 cell susceptibility to $TNF{\alpha}$ - induced apoptosis. Treatment with hsp27-specific antisense oligonucleotides prevented hsp27 protein expression and abolished the protective effects of heat shock and estrogen treatment on $TNF{\alpha}$- induced apoptosis. Hsp27 is a determinant of osteoblast apoptosis, and estrogen treatment increases hsp27 levels in cultured osteoblastic cells. Hsp27 contributes to the control of osteoblast apoptosis and may be manipulated by estrogenic or alternative pathways for the improvement of bone mass.

• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.630-637
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• 1998

Enzymatic properties of immobilized transglucosidase (TG) from Aspergillus niger was characterized and compared with soluble TG. Michaelis-Menten constant $(K_m)$ and maximum velocity $(V_{max})$ of immobilized TG were $122\;mM,\;3.9{\times}10^{-2}\;mM/min$ and in case of soluble TG, 21 mM, 0.4 mM/min. The optimum pH of immobilized TG was pH 5.0 like soluble TG but immobilized TG showed 16% and 45% higher activity than soluble TG at pH 5.0 and pH 6.0. Both of immobilized TG and soluble TG were stable from pH 2.0 to pH 9.0, and therefore their activities in these pH ranges were remained more than 90%. The temperature was optimal at $60{\sim}70^{\circ}C\;and\;70{\sim}80^{\circ}C$ for soluble TG and immobilized TG, respectively. The thermal stability of immobilized TG was significantly improved than that of soluble TG, and immobilized TG retained $32{\sim}40%$ higher activity than soluble TG. D-values from thermal inactivation of immobilized TG were 7690 sec at $65^{\circ}C$, 83 sec at $75^{\circ}C$, 7.2 sec at $80^{\circ}C$. Z-values of soluble and immobilized TG were $6.4^{\circ}C\;and\;5.3^{\circ}C$, respectively. The little difference of activation energies of soluble TG and immobilized TG supposed that there was little difference in mass transfer limitation during the reaction of soluble TG and immobilized TG.

• Journal of Aquaculture
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• v.12 no.3
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• pp.175-183
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• 1999

We have shown previously that the sequence of olive flounder (Paralichthys olivaceus) hsp70-related cDAN has a high similarity with those of cognate hsc70 of other species (Kim et al., 1999; J. Aquaculture, 12:91-100). In order to investigate whether this gene encodes the congate hsc70, we examined the expression of this gene in normal and heat-shocked conditions. By in vitro translation, this gene encoded a 70 kD protein which was constitutively experessed and was not induced by heat shock. This translated protein was recognized by anti-hsp/hsc70 antibody. Tests of heat-inducibility showed that this gene was constitutively expressed in normal conditions and its expression was not increased after heat shock. The expression levels of this gene were high in stomach, gill, intestine, kidney and brain, moderate in liver, and comparatively low in overy and heart. Furthermore, Northern blot analysis of transcript expression showed that the corresponding mRNA were detected throughout embryonic development in the absence of any heat shock. These results provided evidence that olive flounder hsp70-related cDNA encoded to cognate member of hsp70 family, hsc70.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.1
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• pp.101-101
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• 2003

본 연구는 남은 음식물을 유산균을 이용하여 발효 사료화 하기 위해 실시하였다. 발효를 촉진시키기 위한 균주로는 Lactobacillus acidophilus를 사용하였고 최적의 발효조건을 갖는 공기 주입량을 알아보기 위해 시료의 발효 조건을 각각 달리 하였다. 시료는 교반하지 않고 공기주입 또한 없는 혐기적 조건의 것과 50rpm의 속도로 교반하면서 0.25v.v.m의 공기를 주입한군, 70rpm의 속도로 교반하면서 0.5v.v.m의 공기를 주입한 군으로 나누었다. 시료는 모두 $37^{\circ}C$로 유지하면서 48시간 발효 시키며 12시간 단위로 시료를 채취하였다. p.H와 유기산함량, 환원당함량과 유산균수를 측정하여 남은 음식물을 발효시키기 위한 최적의 공기 주입량을 알아보았다. 실험결과 50rpm 0.25v.v.m에서 가장 낮은 p.H를 보여주었고 유기산 함량과 환원당 함량은 70rpm 0.5v.v.m에서 가장 높은 함량을 보였다. 유산균은 50rpm 0.25v.v.m에서 가장 많은 증식되었음을 보여주어 적절한 공기의 주입이 남은 음식물의 발효를 촉진하는 것으로 보여진다.

• Journal of Korean Society on Water Environment
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• v.32 no.1
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• pp.89-97
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• 2016

Digital Elevation Models (DEMs) have been used to represent the effects of topography on soil erosion. A DEM of 30 m resolution is frequently used in hydrology and soil erosion studies because the National Water Management Information System (WAMIS) provides a 30 m resolution DEM at national scale on its web site. However, the Ministry of Environment recommends the use of a DEM with 10 m resolution for evaluation of soil erosion due to the fact that soil erosion estimation is to some degree affected by the spatial resolution of DEM. In this regard, a DEM with 5 m resolution was resampled for 10 × 10 m, 20 × 20 m, 30 × 30 m, 50 × 50 m, 70 × 70 m, and 100 × 100 m resolutions, respectively. USLE LS factors and soil erosion values were evaluated using these datasets. Use of a DEM with at least 30 m resolution provided reasonable LS factors and soil erosion values at a watershed.