• 펄프종이기술
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• 제48권2호
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• pp.28-33
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• 2016

This study was conducted to investigate the effects of deep eutectic solvent (DES) treatment on properties of TMP fibers and handsheets. DES was prepared by mixing of lactic acid and betaine (L and B), and the molar ratio of these two components mixtures was controlled to 2:1 (L:B=2:1) and 5:1 (L:B=5:1). As results, lignin was partly extracted from the TMP fibers. Especially, the delignification of TMP samples was promoted according to the increase of the molar ratio of lactic acid. Except for tear index, both tensile index and burst index of handsheets were increased when higher molar ratio of lactic acid was mixed for DES preparation. However, the LB DES treatment of TMP fibers didn't give any effect on the optical properties of TMP handsheets. The plausibility of TMP fiber was to be enhanced by LB DES treatment.

• Journal of Microbiology and Biotechnology
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• 제26권9호
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• pp.1579-1585
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• 2016

Sugar esters are valuable compounds composed of various sugars and fatty acids that can be used as antibacterial agents and emulsifiers in toothpaste and canned foods. For example, fructose fatty acid esters suppress growth of Streptococcus mutans, a typical pathogenic bacterium causing dental caries. In this study, fructose laurate ester was chosen as a target material and was synthesized by a transesterification reaction using Candida antarctica lipase B. We performed a solvent screening experiment and found that a t-butanol/dimethyl sulfoxide mixture was the best solvent to dissolve fructose and methyl laurate. Fructose laurate was synthesized by transesterification of fructose (100 mM) with methyl laurate (30 mM) in t-butanol containing 20% dimethyl sulfoxide. The conversion yield was about 90%, which was calculated based on the quantity of methyl laurate using high-performance liquid chromatography. Fructose monolaurate (M_r 361) was detected in the reaction mixture by high-resolution mass spectrometry. The inhibitory effect of fructose laurate on growth of oral or food spoilage microorganisms, including S. mutans, Bacillus coagulans, and Geobacillus stearothermophilus, was evaluated.

• 환경위생공학
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• 제22권1호
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• pp.75-83
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• 2007

Clove extract by methanol increased expression of the tyrosinase gene on B16 mouse melanoma cells containing tyrosinase promoter. $10{\mu}g/mL$ and $100{\mu}g/mL$ of the extract showed expression rate of the tyrosinase gene about 138% and 245%, respectively, compared with control. At $500{\mu}g/mL$, expression rate of the extract was impossible to measurement by high cytotoxicity. The solvent fraction of methylene chloride also exhibited highly expression rate as methanol extract. However, the solvent fractions of butyl alcohol and water showed repressive effect on expression of tyrosinase gene at $500{\mu}g/mL$. In MTT assay, cell survival rate of the extract exhibited similar to expression rate of tyrosinase gene. That is, $10{\mu}g/mL$ and $100{\mu}g/mL$ of the extract showed the cell survival rate about 128% and 187%, respectively.

• Bulletin of the Korean Chemical Society
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• 제25권5호
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• pp.699-703
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• 2004

Solvolyses of isopropylsulfonyl chloride (IPSC) in water, D_2O,\;CH_3OD$, and in aqueous binary mixtures of acetone, ethanol and methanol are investigated at 25, 35 and 45$^{\circ}C$. The Grunwald-Winstein plot of first-order rate constants for the solvolytic reaction of IPSC with $Y_{Cl}$ (based on 2-adamantyl chloride) shows marked dispersions into three separate lines for three aqueous mixtures with a small slope (m < 0.30). The extended Grunwald-Winstein plots for the solvolysis of IPSC show better correlation. The kinetic solvent isotope effects determined in water and methanol are in consistent with the proposed mechanism of the general base catalyzed and/or $S_AN/S_N2$ reaction mechanism for IPSC solvolyses based on mass law and stoichiometric solvation effect studies.

• 한국식품영양학회지
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• 제30권1호
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• pp.51-58
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• 2017

Antioxidant activities of 80% methanol, water, and 70% ethanol extracts of Lentinula edodes GNA01 were compared and estimated. The yield of Lentinula edodes GNA01 was identified to be in the following order: water>70% ethanol>80% methanol, but there was no significant difference between 80% methanol and 70% ethanol extracts. The highest total phenolic content (TPC) and total flavonoid content (TFC) were found in water extract, and TPC of 80% methanol extract was higher than that of 70% ethanol extract and TFC of 70% ethanol extract was higher than that of 80% methanol extract. Water extract exhibited the strongest DPPH, ABTS radicals, and nitrite scavenging activities, $Fe^{2+}$ chelating ability, and FRAP among the three extracts. In addition, antioxidant activity of 80% methanol extract was higher than that of 70% ethanol extract in most of the experiments. As a result, antioxidant activity of Lentinula edodes GNA01 showed a difference according to extraction solvent and concentration; nevertheless, water extract exhibiting high polarity had the strongest antioxidant effect. Consequently, water extract from Lentinula edodes GNA01 is anticipated to be useful for the development of a high value-added functional product.

• Ocean and Polar Research
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• 제37권4호
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• pp.279-285
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• 2015

In this study, the potential capacity of the crude extract and its solvent fractions from S. siliquanstrum against adipocyte differentiation were evaluated in 3T3-L1 adipocytes. The anti-adipogenic effect of S. siliquanstrum was evidenced by the fact that its crude extract decreases the lipid accumulation of differentiating cells and the expression levels of crucial adipogenesis markers, peroxisome proliferator-activated receptor $(PPAR){\gamma}$ and CCAAT/enhancer-binding protein $(C/EBP){\alpha}$. All solvent fractions except the water fraction showed an observable decrease in lipid accumulation and $PPAR{\gamma}$ and $C/EBP{\alpha}$ expressions. In conclusion, these results suggest that S. siliquanstrum possesses obesity inhibiting components, which may possibly be used as a valuable anti-obesity agent for reducing the risk of obesity.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2009년도 추계학술발표회 논문집
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• pp.79-84
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• 2009

Understanding the polymer adsorption in particle/binder/solvent system is important to achieve successful film products. While most of the reported work has dealt with the suspension microstructure, a few studies have focused on film formation. We investigated the effect of adsorption on film formation through measurement of adsorption amount in suspension and stress development in drying film with respect to mixing time ($t_m$). All of the adsorption amount (PVA), characteristic stress ($\sigma_{ch}$) exhibited similarities expressed by the form of $1-e^{t_m/{\tau}}$. The porous and non-unifonn dried film at short tm became close-packed and uniform with longer $t_m$. We found that polymer adsorption plays the key role in film fonnation as it introduces steric repulsion in suspension and suppresses the flocculation during solvent evaporation. We also found that the mixing time for the saturated polymer adsorption is the important variable to acquire the consolidated and uniform film microstructure.

• 공업화학
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• 제19권5호
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• pp.484-490
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• 2008

폴리비닐피로디온을 서로 다른 끓는점, 유전상수, 쌍극자모멘트를 갖는 다양한 용매(메탄올, 에탄올, 2-프로판올, 부탄올, 아세톤, 메틸렌클로라이드 및 DMF)에 용해시켜 전기방사를 시도하여 섬유의 특성을 연구하였다. 전기 방사된 폴리비닐피로디온은 방사용액의 점도, 전기전도도 및 표면장력에 영향을 받는다. 점도가 $0.114kg/m{\cdot}s$ 이상, 전기전도도는 1.02 mS/m 이상, 표면장력은 30.0 mN/m 이하에서 섬유가 형성되었다. 에탄올 용매계에서 폴리비닐피로디온의 평균직경은 인가전압이 10 kV에서 20 kV 증가시킴에 따라 1710에서 5454 nm까지 증가하였다.

• 대한화학회지
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• 제61권1호
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• pp.25-28
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• 2017

Solvolyses with the reaction center being the sulfur of 4-(chlorosulfonyl)biphenyl ($C_6H_5C_6H_4SO_2Cl$, 1) was studied under solvolytic conditions and the extended Grunwald-Winstein equation was applied. The thirty five kinds of solvents gave a reasonable extended Grunwald-Winstein plot with a correlation coefficient (R) of 0.940. The sensitivity values (l = 0.60 and m = 0.47) of 1 were smaller than those obtained for benzenesulfonyl chloride ($C_6H_5SO_2Cl$, 2; l = 1.10 and m = 0.61) proposed to undergo dissociative $S_N2$ mechanism. These l and m values for the solvolyses of 1 can be considered to support a $S_N2$ pathway with some ionization reaction. The activation parameters, ${\Delta}H^{\neq}$ and ${\Delta}S^{\neq}$, were determined and they are also in line with values expected for a bimolecular reaction. The kinetic solvent isotope effect (KSIE) of 1.26 is also in accord with a bimolecular mechanism, probably assisted by general-base catalysis.

• 대한화학회지
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• 제17권6호
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• pp.411-415
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• 1973

Cyanide ion과 triphenylmethane dye와의 반응은 cetyltrimethyl ammonium bromide(CTABr)의 cationic micelle에 의하여 현저히 반응속도가 빨라지며 sodium lauryl sulfate(NaLS)의 anionic micelle에 의하여 반응속도가 늦어진다. 또한 CTABr존재하의 반응은 inorganic anion에 의하여 inhibition, 되며 NaLS존재하의 반응은 inorganic cation중의 몇가지, 특히 $Zn^{++},\;Cd^{++}$등에 의하여 현저하게 반응이 빨라지는 salt effect를 나타낸다. 물과 잘 혼합되는 몇가지 유기용매의 micelle catalysis에 대한 영향은 대체로 수용액 일때보다 작게 나타나서 반응속도가 늦어지거나 malachite green과의 반응에서 methanol은 수용액일때보다 반응속도가 빨라지는 특이한 solvent effect를 나타내었다.