• Journal of Korean Society of Forest Science
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• v.90 no.4
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• pp.413-419
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• 2001

This study investigated pH values and EC changes of rainfall and stemflow were investigated for 5 tree species such as Pinus koraiensis, P. densiflora, Larix leptolepis, Quercus variabilis and Q. mongolica in the Experiment Forests, College of Forest Science, Kangwon National University. The results were as follows; 1. Mean month pH values of stemflow were much lower than those of rainfall. Among tree species, pH values of the coniferous such as P. densiflora, P. koraiensis and L. leptolepis were lower those of the deciduous such as Q. mongolica and Q. variabilis. Mean month pH values of stemflow ranged from 3.23 to 5.03 (average : 4.23) for P. koraiensis, 3.57 to 5.16 (average : 4.36) for P. densiflora, 3.41 to 6.69 (average : 4.45) for L. leptolepis, 3.86 to 6.11 (average : 4.70) for Q. variabilis and 4.39 to 6.13 (average : 5.18) for Q. mongolica. 2. Mean month EC of the coniferous species was 1.5 to 2 times higher than that of the deciduous species. Mean month EC of stemflow for P. koraiensis, P. densiflora, L. leptolepis, Q. variabilis and Q. mongolica was ranged from 29.0 to $946.5{\mu}S/cm$(average : $258.5{\mu}S/cm$), 18.6 to $907.5{\mu}S/cm$(average : $220.3{\mu}S/cm$), 27.0 to $918.0{\mu}S/cm$(average : $216.2{\mu}S/cm$), 16.5 to $301.6{\mu}S/cm$(average : $125.4{\mu}S/cm$) and $25.2{\sim}225.7{\mu}S/cm$(average : $101.5{\mu}S/cm$), respectively. 3. Average pH values and EC were highly variable according to season. Average pH values appeared lower in spring than those in summer and autumn, but EC appeared higher in spring than those lower in summer and autumn. 4. According to precipitation, there was little difference in and pH values of stemflow the coniferous and the deciduous showed low pH valuess in the case of less than 50mm precipitation. However, EC of stemflow showed a difference depending on the precipitation, and EC of the coniferous and the deciduous was high more than $100{\mu}S/cm$ at the precipitation of less than 50mm.

• Korean journal of applied entomology
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• v.58 no.3
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• pp.251-258
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• 2019

A series of studies were conducted to monitor the seasonal occurrences of onion thrips (Thrips tabaci) and allium leafminers (Acrolepiopsis sapporensis) in northern-type garlic fields, and to evaluate their susceptibility to insecticides. The results showed that the T. tabaci population density increased from mid- March to mid-June, that of A. sapporensis began to increase in mid-March and peaked twice by early July. Also, using recommended concentrations, the insecticidal activities of nine insecticides against these two pests were evaluated. Under laboratory conditions, clothianidin SC, chlorfenapyr EC, dimethoate EC, imidacloprid WP, and cyantraniliprole + thiamethoxam WG insecticidal activities against T. tabaci were all 100%, as well as. those of cyantraniliprole EC, pyridalyl EW, spinetoram SG and abamectin + chlorantraniliprole SC against A. sapporensis. Insecticides, with high insecticidal activities, were evaluated on the two pests under laboratory conditions, and the results showed that all the insecticides exhibited strong insecticidal activities, and the mortality of two pests was >90%.

• The Korean Journal of Zoology
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• v.16 no.2
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• pp.109-118
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• 1973

The morphological changes of the enterochromaffin cells in the gastrointestinal mucosae of Rana amurensis were observed during pre-hibernating, hibernating, post-hibernating and active period. The results of the observation are as follow: 1. The relative values of the enterochromaffin cell numbers in the pre-hibernating, hibernating and post-hibernating groups as compared with the active group are 1.50, 0.36 and 0.90, respectively. 2. In active and pre-hibernating groups, the enterochromaffin cells are large and middle-amount granulated cells and the sparse granulated cells increase significantly during hibernating and post-hibernating periods. 3. It is concluded that the morphological changes of enterochromaffin cells are due to lowered metabolic acitvities especially lowered endocrine activity during hibernation.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.12
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• pp.1277-1284
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• 2005

Alkylphenol Polyethoxylate(APEs) and their metabolites were determined in the aquatic environment in the central Nakdong river basin. The concentrations of APE's ranged between $0.62{\sim}11.70\;{\mu}g/L$ from the Nakdong and the Kumho rivers, and were $70.00{\sim}212.50\;{\mu}g/L$ in the samples from the 3rd industrial complex stream and the Dalseo stream, which are both heavily polluted by industrial wastewater and domestic wastewater. The APEs revealed a removal rate of more than 87% by biodegradation and adsorption etc. in the wastewater treatment plant. Nonylphenol polyethoxylates(NPnEO) and Nonylphenol carboxylic acid(NPnEC) consisted of APE metabolites shifted from NP($n=4{\sim}10$)EO and NP($n=4{\sim}10$)EC to NP($n=1{\sim}3$)EO and NP($n=1{\sim}3$)EC or removed by the adsorption of activated sludge during the biological wastewater treatment process. Upper streams have a higher distributed rate of NP($n=7{\sim}10$)EO than water downstream. Continuous monitoring is necessary for non-point sources as well as point sources, such as a wastewater treatment plant. Effluent concentrations of nonylphenol(NP) in industrial wastewater and domestic wastewater averaged about 4.33 and $1.70\;{\mu}g/L$, respectively. In addition, the removal rate average was 90% in the wastewater treatment plant. NP concentrations in the rivers did not exceed $1.0\;{\mu}g/L$, which are prescribed by environmental risk concentration in the USA and Europe. However, NP required continuous monitoring, which detected over $0.1\;{\mu}g/L$ in all river areas.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.517-524
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• 2018

The purpose of this study was to investigate the density of thrips, and insecticidal resistance for effective control of Western flower thrips in greenhouse. The presence and density of the thrips was investigated using yellow colored-sticky trap in a cucumber field from May to August in Cheon-an. The results of the investigation revealed the existence of the following thrips species; Frankliniella occidentalis, F. intonsa, Thrips palmi, T. tabaci, Scirtothrips dorsalis, Microcephalothrips abdominalis, and T. nigropilosus. The predominant pest was found to be the western flower thrips. To survey the western flower thrips insecticidal resistance, we established the discriminating concentration (DC), recommended concentration (RC) and $2{\times}$recommended concentration ($2{\times}RC$) of nine insecticides; Emamectin benzoate EC, spinetoram SC, Chlorfenapyr EC, Spinosad SC, Cyantraniliprole EC, Acetamiprid WP, Dinotefuran WG, thiacloprid SC and thiamethoxam SC. The bioassay of about five local populations was conducted using the leaf-dipping method. In all local populations, insecticidal resistance in western flower thrips had not developed in emamectin benzoate EC (RC, $10.8{\mu}L\;L^{-1}$), chlorfenapyr EC (RC, $50.0{\mu}L\;L^{-1}$), spinetoram SC (RC, $25.0mg\;L^{-1}$), and spinosad SC (RC, $50.0mg\;L^{-1}$). However, insecticidal resistance in RC was found to have developed in cyantraniliprole EC (RC, $50.0{\mu}L\;L^{-1}$) and four insecticides of neonicotinoid type. Insecticidal activity of 95% or more was observed in each population when cyantraniliprole EC tested in $2{\times}RC$. However, the neonicotinoid types showed different insecticidal activity in $2{\times}RC$.

• Food Science and Preservation
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• v.23 no.5
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• pp.696-703
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• 2016

The purpose of this study was to determine the optimum re-extraction conditions of ethanol from catechin in Korean green tea (Camellia sinensis L.) using response surface methodology (RSM). The experiments were carried out according to a five level and two variable central composite design (CCD). The two independent variables were solvent ratio to sample content (1, 4, 7, 10, 13 mL/g) and extraction temperature (-20, -10, 0, 10, $20^{\circ}C$) on the dependent variables including yield, epigallocatechin (EGC), epicathchin (EC), epigallocatechingallate (EGCG), epicatechingallate (ECG), total catechin and caffeine. ANOVA results showed that Coefficients of determination ($R^2$) of estimated models for dependent variables were ranged from 0.9054~0.9778, while $R^2$ of caffeine were estimated 0.8770. The optimum ranges for the maximized extraction including yield, EGC, EC, EGCG, ECG, caffeine and total catechin were 4.5~7.5 mL/g in ratio of ethanol to sample and $-8{\sim}8^{\circ}C$ in extraction temperature. The actual values of yield, EGC, EC, EGCG, ECG, caffeine and total catechin, respectively, at the optimized conditions were 35.02%, 13.31%, 3.978%, 19.11%, 4.29%, 5.30% and 40.68%.

• Korean Journal of Pharmacognosy
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• v.30 no.2
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• pp.151-157
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• 1999

In order to find less toxic antiherpetic agents, the effect of natural quercetin on the plaque formation of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) was studied in vitro in cell culture monolayers employing the technique of viral plaque reduction assay. Quercetin caused a concentration-dependent reduction in the plaque formation of herpesviruses. It also exhibited more potent antiherpetic activity on HSV-1 with effective concentration $(EC_{50})$ of $18.7\;{\mu}g/ml$ than on HSV-2 with $EC_{50}$ of $24.5\;{\mu}g/ml$. The combined antiherpetic effects of quercetin with nucleoside antiherpetic agents, acyclovir and vidarabine, were examined on the multiplication of these two strains of herpesviruses in Vero cells by the combination assay. The results of combination assay were evaluated by the combination index (CI) that was calculated by the multiple drug effect analysis. The combinations of quercetin with acyclovir on HSV-1 and HSV-2 showed more potent synergism with CI values of $0.19{\sim}0.89$ for 50%, 70%, 90% effective levels than those with vidarabine with CI values of $0.43{\sim}1.46$.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.2
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• pp.122-128
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• 2001

In order to find out the effect of nitrogen fertilizers on soil pH, EC, $NO_3-N$ and lettuce growth, this study was conducted by pot experiment in plastic film house condition. The square-pot which was $42{\times}54.5{\times}22cm$ in length, width and height, respectively, was filled with two kinds of soils in different soil EC as $0.20dS\;m^{-1}$ and $1.13dS\;m^{-1}$. Seven kinds of nitrogen fertilizers (urea, potassium nitrate, calcium nitrate, ammonium nitrate, ammonium sulphate, complex fertilizer A(11-10-10) and complex fertilizer B(12-12-12)) were treated in same standard rate of nitrogen for lettuce, transplanted the six lettuce seedlings of 10 days grown per pot, and have been grown for 38~44 days with three times harvesting. Soil pH was increased with the potassium and calcium nitrate treatments and decreased with ammonium nitrate, ammonium sulphate, complex fertilzer A and B, and the pH of urea treatments was kept the same value as the pH of before experiment. The growing status of lettuce seedling were surveyed during the early period after transplanting and withering of seedling was occured in all treatments. The withering rates were 10% in soil of EC $0.20dS\;m^{-1}$ and 44% and 42% in complex fertilizer and ammonium sulphate treaments, respectively, in soil of EC $1.13dS\;m^{-1}$. $NO{_3}^-$ contents of lettuce were about $1,000{\sim}2,000mg\;kg^{-1}$ based on fresh weight and these contents were considered to be lower to compare the $NO{_3}^-$ level of EU countries.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.4
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• pp.85-94
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• 2016

The purpose of this study was to characterize the coffee ground and its possibility to develop the antifungal activity. pH, EC, and Zn contents of the coffee ground from coffee shops were higher than those of commercial coffee ground, but there was no significant difference in $K_2O$, CaO, MgO, $Na_2O$, Mn contents. The antimicrobial activity of the water soluble extracts from the coffee shop and the commercial coffee ground were tested for six major plant pathogens, Rhizoctonia solani, Sclerotinia sclerotiorum, Fusarium oxysporum, Phytophthora capsici, Alternaria alternata, and Botrytis cinerea. The result showed that there was reliable antifungal activity against all of tested plant pathogenic fungi. The inhibition effects of coffee ground compost extract on the spore germination and zoospore formation were investigated. Water soluble extracts of the coffee ground compost mixture added with 10% sesame oil cake were significantly inhibited the growth of conidia germination of A. altanata and zoospore formation of P. capsici in vitro. For investigating the functional materials of coffee ground compost, it was measured the total polyphenolic compounds contents with 30 days interval during decomposing coffee ground for 90 days. The total polyphenolic content increased with decomposing periods, and it observed that the highest total polyphenolic content was $0.35{\pm}0.03mg\;GAE/g$ on the 90th day in the coffee ground compost added with 10% sesame oil cake.

• YAKHAK HOEJI
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• v.43 no.4
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• pp.469-473
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• 1999

EA, the water soluble substance, was prepared from the carpophores of Elfvingia applanata (Pers). Karst. Anti-influenza A virus (anti-Flu A) activity of EA was examined of Vero cells by plaque reduction assay in vitro. And the combined antiviral effects fo EA with interferon (IFN) alpha and gamma were examined on the multiplication of Flu A with 50% effective concentration ($EC_50$) of 1.50 mg/ml. The results of combination assay were evaluated by the combination index (CI) that was analysed by the multiple drug effect analysis. The combination of EA with IFN alpha on Flu A showed more potent synergism with CI values of 0.50~0.52 of 50%, 70%, 90% effective levels than that with IFN gamma with CI values of 0.82~0.99.