• Journal of Environmental Health Sciences
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• v.10 no.2
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• pp.61-68
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• 1984

공기 중에는 benzo(a)pyrene을 위시한 여러 가지 polynuclear aromatic hydrocarbons(PNAs)가 존재하고 있으며, 그 측정방법이 매우 복잡하여 아직 통일된 적절한 방법이 없다. 본 연구는 공기 중의 PNAs를 측정하기 위한 적절한 방법을 개발하기 위하여 여러 가지 실험을 실시하였고 또 실제로 근로자들을 대상으로 공기를 채취하여 분석한 결과는 다음과 같다. (1) 공기 중 PNAs의 채취방법으로는 Teflon filter와 Polyurethane foam 또는 XAD-2를 연결하여 사용하는 것이 가장 좋은 효과를 보였다. (2) 검체에서 PNAs를 추출하는 방법으로는 methylene chloride를 이용한 초음속진동법 (ultra sonication)이 효과적이었다. benzene과 cyclohexane은 추출효과가 methylene chloride보다 적었으며, 초음속진동시간은 15분이 가장 적절하였다. (3) 분석법으로는 high pressure liquid chromatograph(HPLC)가 적절하였다.

• Bulletin of the Korean Chemical Society
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• v.8 no.4
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• pp.313-318
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• 1987

The approximate rate and stoichiometry of the reaction of excess Thexylbromoborane-methyl sulfide, $ThxBHBr{\cdot}SMe_2,$ with selected organic compounds containing representative functional groups under standardized conditions (methylene chloride, $0^{\circ}C)$ were studied in order to characterize the reducing characteristics of the reagent for selective reductions. The selectivity of the reagent was also compared to the selectivity of thexylchloroborane-methyl sulfide. Thexylbromoborane appears to be a much milder and hence more selective reducing agent than thexylchloroborane. The reagent tolerates many organic functionalities. Thus, the reagent shows very little reactivity or no reactivity toward acid chlorides, esters, epoxides, amides, nitro compounds including simple olefins. However, this reagent can reduce aldehydes, ketones, carboxylic acids, nitriles, and sulfoxides. Especially the reagent reduces carboxylic acids including ${\alpha},{\beta}$ -unsaturated ones and nitriles to the corresponding aldehydes. In addition to that, thexylbromoborane shows good stereoselectivity toward cyclic ketones, much better than the chloro-derivative.

• Journal of the Korean Chemical Society
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• v.30 no.5
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• pp.465-474
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• 1986

The solvent extraction and cleanup processes for the simultaneous gas-liquid chromatographic determination of 11 kinds of organophosphorous pesticide residues in crops were investigated. The extracts dissolved with acetone were partitioned with petroleum ether after adding saturated NaCl solution. Evaporated the partitioning solvent, the residue was dissolved in methylene chloride and eluted through mixed adsorbent (1 : 2 : 4 of activated carbon, magnesia and diatomaceous earth) with methylene chloride as an eluent. The pesticides recovered were 82∼105% and the impurities were effectively removed.

• Journal of Pharmaceutical Investigation
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• v.24 no.4
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• pp.273-279
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• 1994

The stability of three oximes, Hl-6 [(4-carbamoyl-2'[(hydroxyimino)-methyl]- 1,1'-oxydimethylenedi-(pyridinium chloride)], Hl-CN [(4 cyano-2'-[(hydroxyimino)-methyl] -1,1'-oxydimethylene-di-(pyridinium chloride)], and 2-PAM [pralidoxime chloride] in aqueous solutions was evaluated by HPLC assay. The rate of degradation is dependent on the pH as well as the temperature at which the solution is stored. The optimum pH for the stability of these oximes was pH 2 to 3. The degradation rate constant for 2-PAM ($k\;at\;70^{\circ}C$, $2.07{\times}10^{-4}/hr;\;E_a\;value$, 27.2 kcal/mol) was smaller than those for bis-pyridiniumoximes, Hl-6 ($k\;at\;70^{\circ}C$, $3.38{\times}10^{-3}/hr$) and Hl-CN ($k\;at\;70^{\circ}C$, $8.66{\times}10^{-3}/hr;\;Ea\;value$, 20.7 kcal/mol). In mechanistic analyses, it was found that Hl-CN was decomposed through not only the hydrolysis of nitrile group but also the cleavage of methylene ether bridge, in contrast to Hl-6 which was degraded mainly through the cleavage of methylene ether bridge.

• Polymer(Korea)
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• v.34 no.2
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• pp.133-136
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• 2010

Effect of solution film processing conditions on the dimensional stability of TAC film which is used as protection film of liquid crystal display (LCD) has been studied under hot and humid environmental condition (65 $^{\circ}C$, 90%). In addition, the mechanical and optical property changes due to the dimensional instability were also investigated. It was found that the fast solvent evaporation due to the increasing of methylene chloride content in solvent mixtures and decreasing dope concentration caused the lowering of dimensional stability under hot and humid condition. This dimensional stability change also affected the mechanical and optical properties of TAC films as well.

• Korean Chemical Engineering Research
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• v.56 no.3
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• pp.430-434
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• 2018

In this study, an effective diffusion coefficient and mass transfer coefficient were investigated in microwave-assisted drying of paclitaxel for removal of residual methylene chloride. At all the temperatures (35, 45, and $55^{\circ}C$), a large amount of the residual methylene chloride was initially removed during the drying, and the drying efficiency increased when increasing the drying temperature. The effective diffusion coefficient ($1.299{\times}10^{-13}{\sim}2.571{\times}10^{-13}m^2/s$) and mass transfer coefficient ($1.625{\times}10^{-11}{\sim}4.857{\times}10^{-11}m/s$) increased with increasing drying temperature. The small Biot number (0.0100~0.0151) indicated that the process of mass transfer was externally controlled.

• KSBB Journal
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• v.29 no.6
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• pp.421-425
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• 2014

In this study, the antioxidant activities of fractions (methanol, hexane, methylene chloride, butanol, ethyl acetate and water) of Solanum nigrum L. extract was investigated. The contents of total phenolic compounds of each fractions of methanol, butanol, methylene chloride, ethyl acetate, hexane and water are $4.41{\pm}0.23%$, $5.57{\pm}0.35%$, $9.89{\pm}0.19%$, $9.86{\pm}0.19%$, $1.89{\pm}0.04%$, and $3.18{\pm}0.06%$, respectively. For assay of antioxidant activity, 1,1-diphenyl-2-picryhydrazyl (DPPH) radical scavenging activity, reducing power and nitrite scavenging activity are evaluated. In DPPH radical scavenging activity, the highest effect was obtained from the fraction of ethyl acetate. Reducing power is ordered as ethyl acetate > methylene chloride > methanol. In nitrite scavenging activity, the highest activity was 5.5% (butanol fraction), whereas hexane fraction did not detected. Overall, antioxidant activities are closely related the content of phenolic compound in extracts of S. nigrum L.

• The Korean Journal of Food And Nutrition
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• v.32 no.6
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• pp.581-588
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• 2019

In this study, S. glauca (Bunge) Bunge extract was testified total polyphenol contents, electron donating ability on DPPH, and scavenging ability of superoxide anion radical and hydrogen peroxide. Total polyphenol contents of S. glauca (Bunge) Bunge extract were 7,053.30±915.93 ㎍ GAE/mL. In the fractions, fraction by ethanol was the highest content of 10,973.30±1,000.24 ㎍ GAE/mL. Fractions of ethyl acetate and water were 2,386.70±166.53 ㎍ GAE/mL, 2,413.30±41.63 ㎍ GAE/mL respectively. It was shown that total content of polyphenol according to solvent was significant relation at p<0.05. In the experiment of the electron donating ability, 70% ethanol extract and methylene chloride fraction were -246.15±24.17%, -254.01± 16.54% respectively. In case of ethyl acetate fraction, it was the highest electron donating ability to DPPH radical, 39.06±0.34%, and then water fraction of 36.71±5.55%, ethanol fraction of 29.77±2.57%, gradually. Electron donating abilities revealed significant difference (p<0.05) between the solvents. The superoxide radical scavenging ability of standard material was 0.029±0.0011; 70% ethanol extract of 0.022±0.00052, methylene chloride fraction of 0.027±0.00031, ethyl acetate fraction of 0.024±0.0011, ethanol fraction of 0.021±0.00024 and water fraction of 0.024±0.00019. Hydrogen peroxide scavenging ability of 70% ethanol extract was -0.0029±0.00040 and the others were as follow; methylene chloride fraction (-0.0042±0.00058), ethyl acetate fraction (-0.003± 0.0041), ethanol fraction (-0.0029±0.0015) and water fraction (-0.0028±0.00090).

• Korean Journal of Veterinary Research
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• v.39 no.5
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• pp.1006-1012
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• 1999

This study was conducted to evaluate the ELISA kit for measuring the level of cortisol in the urine. The CV of within-run variation and day to day variation were 0.4~2.8 and 1.8~5.7, respectively. The minimum limitation of measurement was 1ng/ml. The cross reaction was high ($CR_{50}(%)=11.4{\sim}43.2$) in prednisolone, 11-deoxycortisol, 21-deoxycortisol and predinosone. There was low and no cross reaction in other steroid. To develop the ELISA kit we measured the cortisol level in diluted urine with PBS (procedure I), extracted urine with methylene chloride (procedure II) and extracted methylene chloride-extracted urine from thin-layer chromatography (procedure III). The CV value of procedure I, II, III was 9.4~28.3%, 7.2~8.9% and 2.5~5.7%, respectively. There was significant difference between procedure I with II, and pro-cedure I with III(p < 0.01), but no difference between procedure II with III significantly(p < 0.01). The mean UCCR of urine collected through am 8 to 10 was $9.5{\pm}7.6$(0.14~28.0) in 12-month-old dog(n = 47). In this study we can measure the cortisol level in extracted urine with methylene chloride and sequential thin-layer chromatography accurately using ELISA kit.

• Natural Product Sciences
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• v.22 no.3
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• pp.193-200
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• 2016

This study describes the anti-inflammatory, anti-oxidant, and melanogenesis inhibition activities of methanol extract and various organic solvent fractions of Arecae Pericarpium. We examined the inhibition of lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 cells, 1,1-diphenyl-2-picrylhydrazine (DPPH) scavenging activity, mushroom tyrosinase inhibition activity and melanin contents. The study showed that, among all tested fractions, methylene chloride fraction showed the strongest inhibition of LPS-induced NO production in RAW 264.7 cells ($IC_{50}$ value $8.89{\mu}g/mL$) and DPPH radical scavenging activity ($EC_{50}$ value $21.39{\mu}g/mL$). Methylene chloride and ethyl acetate fractions similarly inhibited mushroom tyrosinase activity. Methanol extract exhibited strongest reduction of melanin content in B16F10 melanoma cells. Based on the bioactivity assay results, methylene chloride and ethyl acetate fractions were further separated. Eight phenolic compounds were isolated, which are dimeric syringol (1), catechol (2), 4-hydroxybenzaldehyde (3), vanillin (4), 4-hydroxyacetophenone (5), apocynin (6), protocatechuic acid (7) and 4-hydroxybenzoic acid (8). Among the isolated compounds tested, catechol showed the strongest inhibition of LPS-induced NO production in RAW 264.7 cells. Catechol also showed the concentration-dependent NF-${\kappa}B$ inhibition activity. Arecae Pericarpium might have potentials to be developed as anti-inflammatory agent or dermatological product for skin-whitening agent.