• Natural Product Sciences
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• v.6 no.1
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• pp.40-43
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• 2000

The chemical investigation on the cell suspension culture of Morinda elliptica L. yielded eight anthraquinones, two of which, anthragallol-1,2-dimethyl ether (3) and purpurin-1-methyl ether (4), have not been isolated from the original plant. Other compounds isolated include nordamnacanthal (1), alizarin-1-methyl ether (2), rubiadin (5), soranjidiol (6), $lucidin-{\omega}-methyl$ ether (7), and morindone (8). The structures of anthraquinones were established based on spectral studies.

• Bulletin of the Korean Chemical Society
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• v.23 no.5
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• pp.661-662
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• 2002

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.2
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• pp.158-165
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• 2008

The combustion and exhaust emissions characteristics of a liquefied petroleum gas-di-methyl ether compression ignition engine with a variable valve timing device were investigated under various liquefied petroleum gas injection timing conditions. Liquefied petroleum gas was used as the main fuel and was injected directly into the combustion chamber. Di-methyl ether was used as an ignition promoter and was injected into the intake port. Different liquefied petroleum gas injection timings were tested to verify the effects of the mixture homogeneity on the combustion and exhaust emission characteristics of the liquefied petroleum gas-di-methyl ether compression ignition engine. The average charge temperature was calculated to analyze the emission formation. The ringing intensity was used for analysis of knock characteristics. The combustion and exhaust emission characteristics differed significantly depending on the liquefied petroleum gas injection and intake valve open timings. The CO emission increased as the intake valve open and liquefied petroleum gas injection timings were retarded. However, the particulate matter emission decreased and the nitrogen oxide emission increased as the intake valve open timing was retarded in the diffusion combustion regime. Finally, the combustion efficiency decreased as the intake valve open and liquefied petroleum gas injection timings were retarded.

• Korean Journal of Pharmacognosy
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• v.33 no.3 s.130
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• pp.207-210
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• 2002

The methanol extract from the root of Croton cascarilloides Raeusch. was primarily evaluated for cytotoxic activity in the cultured human lung cancer cell line (A459) and showed cytotoxic potential with $ED_{50}$ value of $5.98\;{\mu}g/ml$. Bioassayguided fractionation of the root extract resulted in 3-acetyl aleuritolic acid, rubiadin-l-methyl ether, and julocrotine. The structures of the compounds were elucidated from the combination of spectroscopic data and references. In addition, the $^{13}C-NMR$ assignments of rubiadin-l-methyl ether were revised.

• Journal of Environmental Health Sciences
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• v.34 no.6
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• pp.403-413
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• 2008

Toxic effect of methyl tert-butyl ether (MTBE), tert-butyl alcohol (TBA) and formaldehyde (FA) on microbial activity and diversity was compared in rice field, leek patch, and tidal mud flat soil samples. MTBE, TBA and FA with different concentrations were added into microcosms containing these soil samples, and placed at room temperature for 30 days. Then the microbial activities such as dehydrogenase and viable cell numbers and microbial community using a DGGE (Denaturing gradient gel electrophoresis) fingerprinting method were measured. Among the samples, dehydrogenase activity in rice field was inhibited the most by MTBE, TBA and FA. The toxic effect was higher according to the following orders: FA > MTBE > TBA. Dominant species in the microcosms contaminated with MTBE, TBA and FA were Chloroflex, Bacilli, gamma-proteobacteria in the rice field sample, Sphingobacteria, Flavobacteria, Actinobacteria, Bacilli, gamma-proteobacteria in the leek patch sample, and Sphingobacteria, Flavobacteria, delta-proteobacteria, gamma-proteobacteria in the tidal mud flat sample.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.8
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• pp.767-773
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• 2010

In recent years, there has been considerable concern over the release of methyl tert-butyl ether (MTBE), a gasoline additive, into the aquifers used as potable water sources. MTBE readily dissolves in water and has entered the environment via gasoline spills and leaking storage tanks. In this study air stripping and ozonation of MTBE in aqueous solution were performed in a laboratory scale batch reacter. The mass transfer rate (N) was evaluated and a values about $1.24{\times}10^{-6}\;mol{\cdot}sec^{-1}$ was found. In the ozonation of MTBE a 8.3% decrease of the COD and a 6.5% decrease of the TOC lead to BOD/COD = 0.03. The peudo first-order rate constants of the ozonation of MTBE was $3.75{\times}10^{-5}\;sec^{-1}$. The resulting Ea of 4.80 kcal；mol-1 was observed for molecular ozone reactions.

• Archives of Pharmacal Research
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• v.26 no.7
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• pp.532-534
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• 2003

Kojic acid dimethyl ether (1), and the known kojic acid mono methyl ether (2), kojic acid (3) and phomaligol A (4) have been isolated from the organic extract of the broth of the marine-derived fungus Altenaria sp. collected from the surface of the marine green alga Ulva pertusa. The structures were assigned on the basis of comprehensive spectroscopic analyses. Each isolate was tested for its tyrosinase inhibitory activity. Kojic acid (3) was found to have significant tyrosinase inhibitory activity, but compounds 1, 2, and 4 were found to be inactive.

• Fisheries and Aquatic Sciences
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• v.12 no.2
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• pp.86-89
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• 2009

2,3,6-Tribromo-4,5-dihydroxybenzyl methyl ether (TDB) from the methanolic extract of the red alga Symphyocladia latiuscula exhibits major antioxidant activity. In this study, the activity of TDB against oxidative damage in deoxyribose and DNA was investigated in vitro for potential applications in preventing mutagenesis caused by DNA damage. TDB inhibited the oxidation of deoxyribose at concentrations of up to $1{\mu}g$/mL in the presence of $Fe^{+3}$-EDTA/$H_2O_2$. Furthermore, TDB showed no pro oxidant activity as determined by absence of the reduction of bleomycin-$Fe^{+3}$ to bleomycin-$Fe^{+2}$, which leads to DNA damage. Based on these results, TDB demonstrated considerable antioxidant activity without prooxidant properties.

• Environmental Analysis Health and Toxicology
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• v.21 no.2 s.53
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• pp.93-102
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• 2006

Methyl tert-butyl ether (MTBE), an octane booster that is added to the reformulated gasoline, has been a widespread contaminant in aquatic ecosystem. MTBE is a recalcitrant pollutant having low biodegradability. Due to its higher water solubility and low octanol-water partition coefficient, it can be rapidly transported to the surrounding water environment. Also, MTBE is a known animal carcinogen, and is classified as a possible human carcinogen by U. S. Environmental Protection Agency. The adverse effect of MTBE to aquatic biota was widely reported. In Korea, the recent detection of MTBE in groundwater near gasoline filling stations has drawn concern to public health and ecosystem. To address this concern, the effect of MTBE to human health and ecosystem was discussed in this review. Also, ecotoxicity data of MTBE for fish, invertebrates, and algae were extensively compared to estimate the hazard concentration 5($HC_5$) of MTBE as a screening level.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.327-327
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• 2006

Methyl glycidyl ether has been polymerized in a controlled fashion at low temperature in toluene using the combination of tetraoctyl ammonium bromide and triisobutyl aluminum. Poly(glycidyl methyl ether)s with molar masses ranging from 3 000 to about 90 000 g/mol and narrow polydispersities (<1.2) were prepared and the dependence of their solubility and LCST in water as a function on their molar masses investigated.