• Korean Journal Plant Pathology
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• v.10 no.2
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• pp.92-98
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• 1994

Phytophthora infestans populations collected from various geographical locations of Korea in 1991 and 1993 were analyzed for mating types and responses to metalaxyl. Both A1 and A2 mating type isolates were detected in 1991. The majority of the isolates were A2 mating type, but no A1 mating type was detected in 1993. About 40% of the isolates collected in 1991 were resistant to metalaxyl, and the distribution of metalaxyl-resistant isolates of P. infestans was strongly associated with their geographic origins in Korea. Metalaxyl-resistant isolates with EC50 values > 50$\mu\textrm{g}$/ml were collected from the northern provinces of Kangwon, Kyungbuk, and Chonbuk, but not from the southern provinces of Kyungnam, Chonnam, and Jeju in 1991. The drastic increase in the degree of quantitative resistance to metalaxyl was detected among the isolates from the southern provinces during 1991~1993. More than 50% of the isolates collected from the southern provinces of Kyungnam and Chonnam in 1993 had EC50 values >50$\mu\textrm{g}$/ml. The province of Kangwon had isolates with the greatest resistance to metalaxyl. this alpine areas might be the origin of metalaxyl-resistant isolates of P. infestans in Korea. The A2 genotype with metalaxyl resistance appears to be displacing the A1 genotype which is presently the predominant genotype in Korea.

• The Transactions of the Korea Information Processing Society
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• v.7 no.5S
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• pp.1687-1695
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• 2000

Recently, many researchers have tried to establish EC framework EC framework for automated contract and brokerage using agent technologies in electronic commerce. Traditional researches, however, often enforced the user's participations during the automated brokerage process of agents an did not supported the procedures and methodologies for satisfying various user's requirements. In this paper, we propose a brokerge framework based on multi-agent to overcome the defects of the previous researches. For the optimal brokerage, the proposed framework is divided into tow layers, which are called competition layer and constraint satisfaction layer. The Agents process behaviors of brokerage through two layers accroding to th proposed message driven communication protocol. W also apply CSP (Constraint Satisfaction Problems) techniques to brokerage process to satisfy various preferential requirements from the user. That is, e model the relationship between buyer agents and seller agents using CSP and propose efficient CSP models for the optimal brokerage as the types of brokerage. Finally, e implemented prototype systems applying the proposed framework and showed the efficiency of he proposed framwork with the experimental results.

• Journal of Microbiology and Biotechnology
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• v.12 no.2
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• pp.279-285
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• 2002

Phytase (myo-inositol hexakisphosphate phospho-hydrolase, EC 3.1.3.8) catalyzes the hydrolysis of phytate (myo-inositol hexakisphosphate) to release inorganic phosphate. A bacterial strain producing phytase was isolated from soil around a cattle shed. To identify the strain, cellular fatty acids profiles, the GC contents, a quinine-type analysis, and physiological test using an API 20NE kit were carried out. The strain was identified to be a genus of Pseudomonas sp. and named as Pseudomonas sp. YH40. The optimum culture condition for the maximum productivity of phytase by Pseudomonas sp. YH40 were attained in a culture medium composed of $1.0\%$ (w/v) glycerol, $2.0\%$ (w/v) peptone, and $0.2\%$ (w/v) $FeSO_4{\cdot}7H_2O$. Within the optimal medium condition, the production of phytase became highest after 10 h of incubation, and the maximal phytase production by Pseudomonas sp. YH40 was observed at $37^{\circ}C$ and pH 6.0.

• Elastomers and Composites
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• v.54 no.1
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• pp.7-13
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• 2019

Recycling of waste polyvinyl chloride plastics has attracted much attention due to environmental problems, but the poor mechanical properties, low thermal stability, frequent breakage of strands, and melt cracking of the waste plastics have limited their widespread use. To overcome these disadvantages of waste PVC (W-PVC), recycled PVC powder blend was prepared by adding high-density polyethylene (HDPE) and ethylene vinyl acetate (EVA) as a heat stabilizer and compatibilizer, respectively. An intermeshing co-rotating twin screw extruder was used to prepare the blend, and the characteristics of the blend were analyzed by SEM and TGA, and by using a UTM and Izod impact tester. The impact strength was improved as the EVA content increased for the W-PVC/HDPE (80/20 wt%) blend. As the HDPE and EVA contents increased in the W-PVC/HDPE/EVA blend, the impact strength increased. SEM observations also revealed the improved interfacial adhesion for the EVA-containing blend.

• Horticultural Science & Technology
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• v.16 no.3
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• pp.347-349
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• 1998

Slow sand filtration was modified and applied for the determination of eliminating efficacy of various fungi and for recommending an easy approach to growers. After 1,500 liter filtration, Fusarium oxysporum was eliminated by several substrates such as activated charcoal (92.5% elimination), silica (90.8%), vermiculite (90.5%), sand (82.3%), perlite (50.4%), and hydroball (21.2%). Silica was able to eliminate several fungi by maximal ratio, which was corresponded to Fusarium oxysporum 120 cfu/mL. Collectotrichum lagenarium 98 cfu/mL. Phytophthora capsici 82 cfu/mL, Botrytis cinerea 62 cfu/mL, Pythium spp. 42 cfu/mL, and Sclerotinia ssp. 52 cfu/mL. In this case, the change of EC was minor and pH was maintained to about 7. In deep flow culture of 'Ddooksum Cheokchookmyeon' lettuce and 'Seokwang' tomato, silica-, activated charcoal-, and vermiculite-based filtration system successfully eliminated Fusarium oxysporum and Phytophthora capsici from the nutrient solution. As a result, these plants were not diseased by ten weeks after inoculation. With this system, growers can easily control the root-zone fungi in the recirculating hydroponic system.

• Journal of Ecology and Environment
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• v.39 no.1
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• pp.61-70
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• 2016

Major objectives of the study were to analyze chemical and biological influences of the river ecosystem on the artificial weir construction at three regions of Sejong-Weir (S_j-W), Gongju-Weir (G_j-W), and Baekje-Weir (B_j-W) during 2008-2012. After the weir construction, the discharge volume increased up to 2.9 times, and biological oxygen demand (BOD) and electrical conductivity (EC) significantly decreased (p < 0.05). Also, the decrease of total phosphorus (TP) was also evident after the weir construction, but still hyper-eutrophic conditions, based on criteria by , were maintained. Multi-metric model of Index of Biological Integrity (IBI) showed that IBI values averaged 21.0 (range: 20-22; fair condition) in the B_wc, and 14.3 (range: 12-18; poor condition) in the A_wc. The model values of IBI in S_j-W and G_j-W were significantly decreased after the weir construction. The model of Self-Organizing Map (SOM) showed that two groups (cluster I and cluster II) of B_wc and A_wc were divided in the analysis based on the clustering map trained by the SOM. Principal Component Analysis (PCA) was similar to the results of the SOM analysis. Taken together, this research suggests that the weir construction on the river modified the discharge volume and the physical habitat structures along with distinct changes of some chemical water quality. These physical and chemical factors influenced the ecosystem health, measured as a model value of IBI.

• Elastomers and Composites
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• v.47 no.2
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• pp.121-128
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• 2012

Waste EPDM(W-EPDM) collected from the automotive weather strip and the gasket of a laundry machine has not been effectively recycled. Using this W-EPDM powder and other ingredients, i.e., binder(polyolefin resin, polyolefin elastomer, etc.), filler and additives, various economic rubber composites were made by extrusion. In advance of main experiments, the effects of ultrasonic treatment of W-EPDM on the property of rubber composites, comparison in the property of the composites of W-EPDM with those of virgin and devulcanized EPDM, and waste tire rubber were investigated. Also, the properties of the rubber composites extruded with a 12-screw extruder were compared with those extruded with twin-screw extruder. Various W-EPDM composites for synthetic turf filler and car mat were extruded and injection molded, and 3 main properties of tensile strength, elongation and hardness were investigated to develop economical and proper recipes of the rubber composites.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.1
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• pp.47-58
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• 2002

Much of the plastic film house soils in the southern part of the Korean peninsula are managed using a upland-paddy rotation culture system (hereafter, RS) to prevent salt accumulation in soil. However, information on the effects of RS on soil properties and environmental conservation is limited. In order to determine the effects of RS on soil properties, 22 fields under RS and 20 fields under a non-rotation system (hereafter, NRS) in plastic film houses were selected in Chinju, in southern Korea, and the P distribution characteristics were investigated, including the chemical properties. The RS contributed to the removal of water-soluble salts in the surface layer and to the redistribution of organic matter evenly in the soil profile. In the AP horizon, available phosphorus levels were $1,611mg\;kg^{-1}$ in RS and $1,789mg\;kg^{-1}$ in NRS, which markedly exceeds the optimum range for plant cultivation. Total P was lower in RS (average $4,593mg\;kg^{-1}$) than in NRS (average $5,440mg\;kg^{-1}$) and this decrease was taken to be an effect of RS. Inorganic P was the predominant form of P in both systems, followed by organic P and residual P. A soil profile showed that total and inorganic P concentrations decreased with depth in both systems. However, organic P increased withdepth in RS, which was in contrast to that noted in NRS. The increase in organic P with depth in RS implied that organically rather than inorganically derived phosphate moved through the soil. The concentrations of water-soluble P, Ca-P and Al-P were higher in NRS than in RS soil profiles, but the Fe-P concentration was higher in RS than in NRS, which might be affected by the anaerobic conditions found in paddy soils. In both systems, the Al-P form of extractable P predominated in the surface layer, followed by Ca-P, Fe-P and water-soluble P. With increasing depth, the composition rate of Ca-P to extractable P decreased to less than 10% in the 60-70cm depth, as Fe-P dominated at this level. The content of water-soluble P, potentially the main source of eutrophication, was higher in NRS than in RS. These results indicated that the RS used in plastic film houses contributed to the removal of water-soluble salts but only slightly decreased the phosphate concentration.

• The Journal of Engineering Geology
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• v.16 no.4 s.50
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• pp.403-409
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• 2006

This study was performed to assess the clay impact on alga growth which was a primary producer, in view of food chain in ecosystem. As clay minerals caused turbidity, a low sedimentation, high adsorption capacity with organic matter, adsorption - desorption effect with ionic chemicals, clay minerals were supposed to have a significant effect on the aquatic system. In study we tried to turn out NOAEL (No-observed-adverse-effect-level) of clay materials on the algae growth inhibition using such as kaolinite, sericite and montmorillonite. This study was indicated. (1) In both of kaolinite and sericite, the $72hr-EC_{50}$ of them shows 2,752 mg/L and 2,775 mg/L, respectively. (2) On the other hand, in the case of montmorillonite, the $72hr-EC_{50}$ is not shown a significant difference to that of control samples. (3) It can be explained that is also a very important parameter in an alga growth. Because an alga growth was increased when the permeability of W visible radiation was increased in all clay cases. (4) It is demonstrated alga growth was affected by the characteristics of clay materials. Hence we can assess the $\ulcorner$water environmental risk assessment caused clay materials$\lrcorner$ using the alga growth inhibition level indirectly.

• Archives of Reconstructive Microsurgery
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• v.15 no.1
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• pp.1-9
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• 2006

The purpose of this study is to determine the effects of selective inducible nitric oxide synthase (iNOS) inhibitor N-[3-aminomethyl]benzyl]acetamidine (l400W) on the reperfused cremaster muscle. The extracellular superoxide dismutase knockout ($EC-SOD^{-/-}$) mice was used to make the experimental window for ischemia-reperfusion injury. The muscle was exposed to 4.5 h of ischemia followed by 90 min of reperfusion and the mice received either 3 mg/kg of 1400W or the same amount of phosphate buffered saline (PBS) subcutaneously at 10 min before the start of reperfusion. The results showed that 1400W treatment markedly improved the recovery of the vessel diameter and blood flow in the reperfused cremaster muscle compared to that of PBS group. Histological examination showed reduced edema in the interstitium and muscle fiber, and reduced nitrotyrosine formation (a marker of total peroxinitrite ($ONOO^-$) in 1400W-treated muscle compared to PBS. Our results suggest that iNOS and $ONOO^-$ products are involved in skeletal muscle I/R injury. Reduced I/R injury by using selective inhibition of iNOS is perhaps via limiting cytotoxic $ONOO^-$ generation, a reaction product of nitric oxide (NO) and superoxide anion ($O_2^-$). Thus, inhibition of iNOS appears to be a good treatment strategy in reducing clinical I/R injury.