• Analytical Science and Technology
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• v.24 no.6
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• pp.435-442
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• 2011

Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardants (BFRs) which have taken much interest recently due to their potential hazardous effects to human body and ecosystem. Many countries and European community prohibits the usage of certain BFRs in electronics and electronic devices (e.g. RoHS). In this perspectives, Korea Research Institute of Standards and Science (KRISS) has designed and practiced proficiency testing programs based on the ISO/IEC 17043 in order to assist laboratory accreditation activities. The programs for interlaboratory comparisons include congeners of PBDE (PBDE-154, 183, 206, 209) in high impact polystyrene (HIPS). A sample bottle that contains 10 g granular HIPS was distributed to 35 participating laboratories and the test results were calculated by the statistical procedure using z-scores to evaluate performance of each laboratory. The results and the laboratory's performance were discussed.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.1
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• pp.119-126
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• 2016

In this study, we separated the lignin from the wood by using the high boiling point solvent for developing more environmental friendly pulping method. High boiling point solvents as Ethers, glycols and ketones were used to remove the lignin in the pine wood meals. The Yield and lignin content of residual wood meals was reduced according to the input of the catalyst. Me-C, E-Ca, TEG and MIBK had the best delignification rate of 9 kinds of high-boiling point solvents. At the hydrolysis ratio of the selected solvents, The TEG was highest remain ratio of carbohydrates and the E-Ca was lowest remain ratio of lignin. And the Me-C was most excellent lignin hydrolysis ratio at the low catalyst. The selectivity of delignification of Me-C, E-Ca, TEG and MIBK solvents were 49.6, 49.9, 53.8 and 53.1%, respectively, and its values were similar to those of the commercial Kraft Pulp.

• Journal of the korean society of oceanography
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• v.36 no.4
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• pp.101-108
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• 2001

Polybrominated diphenylether (PBDEs) congeners, 2,4,4'-TrBDE, 2,2',4,4'-TeBDE, 2,2',4,4',5-PeBDE, 2,2',4,4',5,5'-HXBDE, and 2,2',4,4',5,6-HxBDE, were measured in sediments from 52 stations in the southeastern coastal areas of Korea. Sediment samples were analyzed using gas chromatography coupled to mass spectrometer detector (GC/MSD) with positive electron impact (PEI) mode. New analytical methodology for PBDEs by the isotope dilution method was established using a multi-layer silica gel column chromatography. Total PBDEs levels in sediments for Pohang coast ranged from 1,1 to 33.8 ng/g dry weight (mean 5.3 ng/g dry), from 1.6 to 36.4 ng/g dry weight (mean 5.7 ng/g dry) for Ulsan coast, from 0.8 to 20.3 ng/g dry weight (mean 4.9 ng/g dry) for Busan coast, and from 0.8 to 10.3 ng/g dry weight (mean 4.4 ng/g dry) for Jinhae Bay. PBDEs contamination in surface sediments from Korean southeastern coasts was relatively moderate in comparison to that of other marine environment in the world. The predominant PBDE congeners were 2,2',4,4'-TeBDE and 2,2',4,4',5-PeBDE.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.273-277
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• 1998

The synthesis of hydroxy-terminated poly(propylene carbonate)(HTPPC) was performed by the reaction of propylene carbonate(PC) with alcohol initiator using metal alkoxides, crown ethers and quaternary onium salts as catalysts. The effects of catalyst structure, types and concentration of alcohol, and solvent were investigated. Among the alkoxide catalysts tested, the ones with higher Lewis acidity and with more nucleophilic alkoxide anion showed higher catalytic activity. Mixed catalysts of metal alkoxied and crown ether showed higher conversion of PC than metal alkoxide alone. Quaternary onium salts of bulky cation exhibited higher catalytic activity. High polar solvent showed higher yield of HTPPC and the yield increased with the decrease of [PC]/[Initiator] ratio.

• Analytical Science and Technology
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• v.23 no.1
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• pp.74-82
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• 2010

As a basic research for development of the domestic portable XRF spectrometer, we discussed the analytical results of bench-top and portable XRF methods for RoHS materials of the Cd, Pb, Hg, Cr(IV), polybrominated biphenyls(PBB) and polybrominated diphenyl ehters(PBDE). The instrumental parameters such as measurement time of bench-top and portable XRF were optimized using certified reference materials of polyethylene and polypropylene with 5 hazardous materials of 0~1,200 mg/kg. The quantitative analysis of total-Cr, total-Br, Cd, Hg and Pb in certified reference materials and plastic samples were compared by empirical method, fundamental parameter method of bench-top XRF and portable XRF.

• Journal of Environmental Science International
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• v.5 no.2
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• pp.211-220
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• 1996

New thin-and diselena-crown ethers containing two suffer and selenium donor atoms have been prepared. And then, mercury ($Hg^{2+}$) ion-selective electrodes with PVC-plasticizer (STPB) based on some macrocycles as neutral carriers were also made. The electrochemical selectivities for various ions, and the effects for macrocycles, matrix of membranes, ratio of plasticizer to macrowcles, concentration and pH of test solution were investigated on the $Hg^{2+}$ ion-selective electrodes. The 1, 10-diselena-18-crown-6-PVC-STPB (sodium tetraphenylborate) exhibited good linear responses of ${28.2}\pm{0.6}$ decade-1 for $Hg^{2+}$ ion in the conientration ranges of $10^{-2}~10^{-6}$ M $Hg^{2+}$ ion. This electrode exhibited comparatively good selectivities for $Hg^{2+}$ ion in comparison with alkali and alkaline earth metal ions, some heavy metal ions and rare earth metal ion in the range of pH 2.5~6.0. In addition, this electrode was applied as a sensor in the titration of $Hg^{2+}$ ion with $1^-$ ion in water.

• Advances in Traditional Medicine
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• v.1 no.1
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• pp.45-54
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• 2000

Cannabidiol derivatives (1, 2 and 3), and 5-fluorouracil (4, 5-FU) were tested for their growth inhibitory effects against human oral epitheloid carcinoma cell lines (KB) using two different 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and sulforhodamine B protein (SRB) assay. These compounds showed a potent inhibitory activity in vitro in the micromolar range against KB cell lines. In general, the antitumor activity of these compounds (1, 2, 3 and 4) was in a dose-dependent over the micromolar concentration ranges from $1\;{\mu}M\;to\;100\;{\mu}M$. The comparison of $IC_{50}$ values of these compounds in tumor cell lines shows that their susceptibility to these compounds decreases in the following order: CBD > 5-FU > CBDME > CBDDE by the MTT assay and SRB assay. Cannabidiol derivatives (1, 2 and 3), and 5-FU were tested for their cytotoxic effects on NIH 3T3 fibroblasts using two different MTT assay and SRB assay. These compounds exhibited potent cytotoxic activities in vitro in the micromolar range against NIH 3T3 fibroblasts. In general, the cytotoxic activities of these compounds (1, 2, 3 and 4) were in a dose-dependent over the micromolar concentration range $1\;{\mu}M\;to\;100\;{\mu}M$. The comparison of $CD_{50}$ values of these compounds on NIH 3T3 fibroblasts shows that their susceptibility to these compounds decreases in the following order; CBD > 5-FU > CBDDE > CBDME by MTT assay, CBD > 5-FU > CBDME > CBDDE by SRB assay. These results suggest that cannabidiol (1, CBD) retains the most growth-inhibitory activity against KB cell lines.

• Current Research on Agriculture and Life Sciences
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• v.32 no.2
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• pp.85-89
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• 2014

This study uses turbidity and rheological measurements to examine the effects of the molecular weight (MW), substitution type and substitution degree of cellulose ether and water content on the cooking characteristics of rice noodles, the turbidity of the cooking solution, and the compression strength of the cooked noodles. When increasing the MW of cellulose ether and water content, the turbidity decreased, thereby improving the morphological stability of the rice noodles during cooking. Thus, when controlling the above factors effectively, the rice noodle cooking solution had a lower turbidity than with wheat noodles. Measuring the compression strength of the rice noodles using a rheometer was also effective for examining the pasting characteristics of the rice noodles and texture changes during cooking. As a result, the water content and MW of cellulose ether were found to affect the pasting characteristics and texture of the rice noodles more than the other factors examined.

• The Korean Journal of Pesticide Science
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• v.8 no.4
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• pp.258-264
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• 2004

The pyrazole family was discovered as effective insecticides/acaricides, and fenpyroximate and tebufenpyrad were introduced in the market. In this study, new series of pyrazole oxime ethers were designed and synthesized. The pyrazolone 1 was prepared by the condensation of ethyl acetoacetate with methylhydrazine, and then subsequently subjected to the Vilsmeier-Haack chloroformylation yielding 4-formyl-5-chloro-pyrazole 2. The nucleophilic aromatic substitution of 2 generally allowed the introduction of a wide range of heterocycles into the pyrazole ring. The resulting pyrazole aldehydes 3a-i were readily converted to the corresponding pyrazole oxime derivatives 4a-i, and subsequently to 5-substituted pyrazole oxime ether derivatives 6a-i. The screening assay results clearly show that the activities of 6d were comparable to those of fenpyroximate (6a) against BPH, DBM, and TSSM. It indicates that 6d has a potential to be developed as an insecticidal agent.

• Applied Chemistry for Engineering
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• v.10 no.2
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• pp.201-205
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• 1999

Hydroxypropylmethylcelluloses (HPMC) are cellulose ethers which may be used as the basis for hydrophilic matrices for controlled release oral delivery and offer the advantages of being non-toxic and relatively inexpensive. In this work, we designed new drug release system using HPMC as matrix, manufactured by direct compression technology and have investigated the effects of the controlling factors on drug release from a swellable hydrophillic delivery system. It was found that the release rate of the drug decreased with increasing the polymer molecular weight and the polymer content in tablets, and was independent of compaction pressure and pH of dissolution fluids. Especially, the ability of the anionic surfactant, sodium laurylsulfate, to retard the release of pseudoephedrine hydrochloride from HPMC was characterised. With increasing the concentration of the sodium laurylsulfate within the matrix, drug release rate decreased. It is believed that, provided the pseudoephedrine hydrochloride and the sodium laurylsulfate are oppositely charged, they will bind together in situ within the HPMC matrix, leading to reduced drug release rates.