• Proceedings of the PSK Conference
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• 2003.04a
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• pp.314.2-315
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• 2003

Sophoricoside was isolated as the inhibitor of IL-5 bioactivity from Sophora japonica (Leguminosae). To develope as novel anti-allergic drug. kinetic study was performed in rats. Serum concentration of sophoricoside was measured by gas chromatography-mass spectrometry (GC/MS) in male Sprague-Dawley rat (250${\pm}$10g, n=5) after oral administration of sophoricoside (100mg/kg). (omitted)

• Biomedical Science Letters
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• v.21 no.4
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• pp.241-247
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• 2015

Lactate and ketone bodies are considered biological markers for ketosis and several inherited metabolic disorders. In the current study, the specific ratios of lactate and ketone bodies as analytical tools for differential diagnosis of various lactic acidosis were devised. The study included a protein precipitation step following tert-butyldimethylsilyl derivatisation. Total run time was approximately 30 min including sample preparation and GS/MS analysis. The limits of detection were below 0.1 pg/mL over the targeted 4 analytes. The calibration curve was linear over the concentration range of $0.001{\sim}250{\mu}g/mL$ for pyruvate, beta-hydroxybutyrate, and acetoacetate ($R^2$ > 0.99). Inter-day accuracy and precision were 87.7~94.8% with RSD of 2.5~5.7% at 2 levels. Absolute recoveries (%) of target analytes were 87.0~98.4%. The method was validated for the quantification of lactate and ketone bodies for differentiation of lactic acidosis.

• Journal of Food Hygiene and Safety
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• v.9 no.4
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• pp.185-189
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• 1994

This study was to investigate time-dependent degradation process under various pH condition for organophosphorus(org-p) insecticides, namely Demeton-s-methyl, diazinon, Parathion, Phenthoate, and EPN in several waters. They were analysed by GC-FTD according to standard methods for the examination of water and wastewater. In pH=4, diazinon showed disappearance after 14 days in chromatogram. In pH=11, org-p insecticides were almost degradable after 7 days. In this condition, effect of pH on degradation process was greater than of light. In pH=7, org-p insecticides persisted residues after 112 days except Demeton-s-methyl. In BOD5 120, 250 ppm and domestic water, org-p insecticides showed also rapid degradation process.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2003.10a
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• pp.190-195
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• 2003

A novel microwave-induced pyrolysis of polystyrene in motor oil was performed using a quartz tube reactor with silicon carbide as the microwave absorbent. Different pyrolysis conditions were investigated, such as time range from 30 minutes to 1 hour and power range from 180 to 250 watt. The distillate components were analyzed with GC-MS, and styrene, 1-methyl styrene, toluene, ethyl benzene were the four main products. Among these, styrene took over 70 percentages. Temperature of the complete pyrolysis using microwave was much lower than that of conventional thermal pyrolysis method.

• Elastomers and Composites
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• v.50 no.4
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• pp.245-250
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• 2015

Recycling of ethylene-propylene-diene terpolymer (EPDM) scrap was tried by blending with polypropylene (PP). EPDM scrap powder was prepared by shear pulverization process at high temperature, which may lead to selective chain scission induced by difference in the critical elastic coefficient. On the other hand, EPDM scrap powder was prepared by adding a selected reclaiming agent during shear pulverization process at high temperature. Terpene as a bonding agent was then introduced to improve adhesion property. PP, used as a matrix for manufacturing thermoplastic elastomer, was modified by the incorporation of dicumyl peroxide and maleic anhydride. The functionalized EPDM and modified PP were blended and cured dynamically at $190^{\circ}C$. The blend materials prepared in this study showed the comparable results to those of conventional TPE in terms of tensile and flow properties. Also, the odor component of recycled EPDM was analyzed using GC-MS.

• Journal of Environmental Science International
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• v.11 no.7
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• pp.743-748
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• 2002

UV photolysis process is little known in parts of air pollution treatment, so there are not many applications in field. Therefore we have to do more experiment and study application possibility for treatment of VOCs(Volatile organic compounds). To solve these problems, we have been studying for simultaneous application of this technology. It has shown that concentration of TCE and B.T.X., diameter of reactor and wavelength of lamp have effected on decomposition efficiency. Analysis of TCE and B.T.X. concentration was carried out by GC-FID. A cylinderical reactor consisting of a quartz tube and a centrally located lamp(${\psi}25mm$) was used. The length and diameter of reactor were 1800mm, 75mm. It has shown that the generated ozone concentration goes up 250ppm when using 64watt ozone lamp. When using Photolysis process only, the rates of fractional conversion of each material are TCE 79%, Benzene 65%, Toluene 68%, Xylene 76%. This phenomenon can be rationalized in terms of the different bond energy that indicates how easily VOCs species can be decomposed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.147-150
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• 1995

High speed machining one of the most effectiv to improve machining accuracy and product in dies and mould. But a study on this is limited to Alumium, light metal etc. This paper presents machining characteristic of gray cast iron in high speed machining with tungsten carbide endmill. It is suggested to measure sutting force, tool wear, surface roughness, surface shape and select of cptimal cutting condition in the high speed machining of gray cast iron. Performance of high speed machine tool was estimated and the relationship between cutting phenomenon and machinabillity was described.

• Research in Plant Disease
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• v.23 no.3
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• pp.268-277
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• 2017

Fusarium head bight (FHB) is a devastating disease on major cereal crops worldwide which causes primarily by Fusarium graminearum. Synthetic fungicides are generally used in conventional agriculture to control FHB. Their prolonged usage has led to environmental issues and human health problems. This has prompted interest in developing environmentally friendly biofungicides, including botanical fungicides. In this study, a total 100 plant extracts were tested for antifungal activity against F. graminearum. The crude extract of Pterocarpus santalinus heartwood showed the strongest antifungal activity and contained two antifungal metabolites which were identified as ${\alpha}$-cedrol and widdrol by GC-MS analysis. ${\alpha}$-Cedrol and widdrol isolated from P. santalinus heartwood extract had 31.25 mg/l and 125 mg/l of minimal inhibitory concentration against the spore germination of F. graminearum, and also showed broad spectrum antifungal activities against various plant pathogens. In addition, the wettable powder type formulation of heartwood extract of P. santalinus decreased FHB incidence in dose-dependent manner and suppressed the development of FHB with control values of 87.2% at 250-fold dilution, similar to that of chemical fungicide (92.6% at 2,000-fold dilution). This study suggests that the heartwood extract of P. santalinus could be used as an effective biofungicide for the control of FHB.

• Applied Biological Chemistry
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• v.34 no.4
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• pp.299-306
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• 1991

When $[U-^{14}C]$ 3,3', 4,4'-tetrachloroazobenzene$([U-^{14}C]\;TCAB)$ was added to the $MM_2$ medium as a sole carbon source for the isolated microorganisms and incubated, some radioactive metabolites were detected by autoradiography. No $^{14}CO_2$ was evolved from $[U-^{14}C]\;TCAB$ which was added as a sole carbon source to an organic matter-free soil inoculated by the isolates, wetted with the $MM_2$ salt medium, and incubated at $30^{\circ}C$. One of the metabolites in pure culture of Achromobacter group VD, which was isolated and identified, was tentatively identified as a compound of m/z 250 by means of GC/MS. The possible pathways for its formation are thought to include dechlorination from the TCAB structure, hydroxylation, ortho fission of the two benzene rings, and reduction of the resulting carboxyl group.

• Journal of Applied Biological Chemistry
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• v.56 no.1
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• pp.53-57
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• 2013

In here, we investigated the quantitative analysis method of indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) with liquid chromatography-mass/mass spectrometry (LC-MS/MS) or gas chromatography-MS. Two ways of clean-up process were investigated for LC-MS/MS instrumental analysis of IAA, but both a simple dilution and hydrophile-lipophile balance (HLB) solid phase extraction (SPE) were not met the optimal recovery rates for quantitative analysis. On the other hand, the clean-up method for GC-MS was finally optimized through HLB-SPE from 250-folds diluted sample and methylation with trimethylsilyl chloride in methanol for 4 h. The limit of detection for methyl ester of IAA and IBA were both 1.4 mg/L, and recovery rates showed 93-107% from the concentrated liquid fertilizer.