• 한국세라믹학회지
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• 제45권2호
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• pp.119-125
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• 2008

The FAS(Fluoroalkylsilane)/Nafion inorganic-organic composite electrolyte membrane was successfully fabricated through sol-gel method. The FAS having hydrophobic functional group and silanol ligands is impregnated in $Nafion^{(R)}$ membrane to reduce methanol crossover. The prepared FAS/Nafion inorganic-organic composite electrolyte membrane consist of the hydrophobic FAS-derived silicate nano-particles and $Nafion^{(R)}$ matrix showed decrease of methanol crossover and reduction of humidity dependence without large sacrifice of proton conductivity. The microstructural analysis of the composite membranes was performed using FESEM and FTIR. And the effect of the incorporation of the hydrophobic FAS-derived silicate nano-particles into $Nafion^{(R)}$ membrane was investigated via solvent uptake, membrane expansion rate, humidity dependency of proton conductivity and contact angle measurement.

• Bulletin of the Korean Chemical Society
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• 제28권2호
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• pp.276-280
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• 2007

In this work, caffeine and some catechin compounds + C, EC, EGC, and EGCG were extracted from green tea by using molecular imprinted polymers (MIP) as sorbent materials in a solid-phase extraction (SPE) process known as MISPE (molecular imprinted solid-phase extraction). For synthesis of MIP, caffeine was employed as the template, MAA as the monomer, EGDMA as the crosslinker, and AIBN as the initiator. A solution of caffeine (0.2 mg/mL in methanol) was utilized in the solid extraction cartridges following loading, washing, and elution procedures with acetonitrile, methanol, and methanol-acetic acid (90/10, %v/v) as the solvents, respectively. This solid-phase extraction protocol was applied for the extraction of caffeine and some catechin compounds from green tea. A comparison was made between the results obtained with the MIP cartridges and a traditional C18 reversed-phase cartridge. It was thereupon found that the recovery of caffeine by the MIPbased sorbent used in this work was almost two and four times greater than that by a commercially available C18 material. A quantitative analysis was conducted by high performance liquid chromatography (HPLC) using a C18 column (5 μm, 250 × 4.6 mm) with methanol/water (40/60, %v/v) as the mobile phase at a flow rate of 0.5 mL/min.

• Journal of Microbiology and Biotechnology
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• 제21권11호
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• pp.1159-1165
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• 2011

Biodiesel is methyl and ethyl esters of long-chain fatty acids produced from vegetable oils or animal fats. Lipase enzymes have occasionally been used for the production of this biofuel. Recently, biodiesel production using immobilized lipase has received increased attention. Through enhanced stability and reusability, immobilized lipase can contribute to the reduction of the costs inherent to biodiesel production. In this study, methanol-tolerant lipase M37 from Photobacterium lipolyticum was immobilized using the cross-linked enzyme aggregate (CLEA) method. Lipase M37 has a high lysine content (9.7%) in its protein sequence. Most lysine residues are located evenly over the surface of the protein, except for the lid structure region, which makes the CLEA preparation yield quite high (~93%). CLEA M37 evidences an optimal temperature of $30^{\circ}C$, and an optimal pH of 9-10. It was stable up to $50^{\circ}C$ and in a pH range of 4.0-11.0. Both soluble M37 and CLEA M37 were stable in the presence of high concentrations of methanol, ethanol, 1-propanol, and n-butanol. That is, their activities were maintained at solvent concentrations above 10% (v/v). CLEA M37 could produce biodiesel from olive oil and alcohols such as methanol and ethanol. Additionally, CLEA M37 generated biodiesel via both 2-step methanol feeding procedures. Considering its physical stability and reusability, CLEA M37 may potentially be used as a catalyst in organic synthesis, including the biodiesel production reaction.

• Korean Chemical Engineering Research
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• 제50권4호
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• pp.678-683
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• 2012

세리아 미세입자는 자동차, 석유공정, 폐수처리 등 다양한 분야에서 촉매로서 널리 쓰이고 있는 중요한 물질이다. 이제까지, 세리아 미세입자를 제조하기 위한 다양한 제조법이 연구되었는데, 본 연구에서는 짧은 반응시간과 간단한 공정이 가능한 초임계 메탄올을 이용하는 입자 제조 공정을 통해 세리아 나노입자를 제조하였다. 회분식 반응기를 이용하여 짧은 시간 안에 세리아 나노입자를 제조하는데 성공하였다. 초임계 메탄올을 이용하여 세리아 나노입자를 제조하는 경우, 다른 첨가제 없이도 약 6 nm의 크기를 갖는 나노입자를 합성할 수 있었다. 이 크기는 같은 온도와 압력조건의 초임계수를 이용하여 표면개질제 없이 합성한 입자보다 훨씬 작은 크기이다. 이는 초임계수와 초임계 메탄올의 밀도 차이와, 초임계 메탄올에서의 세리아 표면에서 일어나는 결정성장을 제한하는 반응, 그리고 초임계 메탄올과 초임계수의 임계점의 차이에서 기인하는 것이다. 또한 여러 가지 유기물을 표면개질제로 첨가하여 표면을 개질한 세리아 나노입자를 제조하였으며, FT-IR과 HR-TEM, TGA를 통해 이를 확인할 수 있었다. 표면을 개질한 세리아 나노입자는 표면개질을 하지 않은 세리아 나노입자와는 다르게, 유기용매에 대한 분산성이 뛰어났으며, 표면개질제로 사용하는 유기물의 양과 종류를 조절함으로써 세리아 나노입자의 크기와 모양을 조절할 수 있었다.

• 한국막학회:학술대회논문집
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• 한국막학회 2004년도 추계 총회 및 학술발표회
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• pp.152-155
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• 2004

• Archives of Pharmacal Research
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• 제11권2호
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• pp.163-165
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• 1988

Penicillin G potassium salt was transformed in high yield to 4-acetoxy-3-phenylacetaminoazetidinone by treatment of mercury acetate, ozonolysis and methanol in sequence.

• 동의생리병리학회지
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• 제19권1호
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• pp.87-91
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• 2005

Dental plaque is a film of microorganisms on the tooth surface that plays an important part in the development of caries and periodontal diseases. Streptococcus mutans (S. mutans) is present in almost all types of dental plaque. Teeth and their supporting structure, the gums (gingiva) are subjected to infection by S. mutans that causes cavities and pyorrhea which, if left untreated, can eventually lead to gingivitis. Various chemical agents have been evaluated over the years with respect to their antimicrobial effects in the oral cavity; however, all are associated with side effects that prohibit regular long-term use. The present study was designed to investigate the effect of Aralia continentalis (Araliaceae) extracts on the growth, acid production, adhesion, and insoluble glucan synthesis of S. mutans. The methanol extract of A. continentalis showed concentration dependent inhibitory activity against the growth and acid production of S. mutans, and produced significant inhibition at the concentration of 0.25, 0.5, 1, 2 and 4 mg/ml compared to the control group. The extracts markedly inhibited S. mutans adherence to HA treated with saliva, and cell adherence was repressed by more than 60% at the concentration of 0.25 mg/ml and complete inhibition was observed at the concentration of 4 mg/ml. On the activity of glucosyltransferase which synthesizes water insoluble glucan from sucrose, methanol extract of A. continentalis showed more than 10% inhibition over the concentration of 0.25 mg/ml. The synthesis of insoluble glucan was decreased in the presence of 0.25 - 4 mg/ml of the methanol extract of A. continentalis. Hence, we conclude that A. continentalis might be a candidate of anticaries agent.

• Korean Chemical Engineering Research
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• 제46권3호
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• pp.550-554
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• 2008

메탄올과 초임계 이산화탄소를 이용하여 $K_2CO_3/ZrO_2$ 촉매상에서 디메틸 카보네이트(dimethyl carbonate, DMC)를 합성하였다. $K_2CO_3$를 함침법으로 지르코니아에 담지시켜 촉매를 제조하였다. 673 K에서 소성했을 때, 칼륨 성분이 지르코니아 표면에 최대한 고르게 분산되었다. 단사정계(monoclinic)의 결정 구조를 갖는 지르코니아 자체는 DMC 생성에 대한 활성이 없었지만 $K_2CO_3$를 담지시켰을 경우 촉매 성능이 향상되었다. 촉매 외에 촉진제로 $CH_3I$를 사용하였다. 촉매와 촉진제의 사용은 DMC 생성을 향상시키는데 중요한 역할을 하였다. 촉매와 촉진제를 적정량 사용하였을 경우 DMC 생성량을 향상시킬 수 있었지만 과량으로 사용했을 경우 DMC 생성 외에 다른 부반응에도 영향을 미쳤다. 메탄올과 초임계 이산화탄소로부터 DMC 생성에 대한 촉매와 촉진제의 영향 및 그 반응 메카니즘을 제시하였다.

• 한국식품영양과학회지
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• 제28권6호
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• pp.1326-1331
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• 1999

In vitro anticancer effect of Chinese cabbage kimchi fractions was investigated by using human cancer cells, AGS human gastric adenocarcinoma cells and HT 29 human colon adenocarcinoma cells. The Chinese cabbage kimchi(fermented for 4 days at 15oC) was fractionated into 7 groups, methanol extract, hexane fraction(fr.), methanol soluble fr., dichloromethane fr., ethylacetate fr., butanol fr. and aqueous fr.. Chinese cabbage kimchi fractions inhibited the growth of AGS and HT 29 cancer cells as dose dependent. In particular, the dichloromethane fr. showed the highest inhibitory effect among other fractions. When the dichloromethane fr.(0.2mg/ml) was treated, the number of AGS and HT 29 survival cancer cells reduced to 12$\times$104/ml and 11$\times$104/ml compared to 166$\times$104/ml and 50$\times$104/ml of the controls, respectively. Chinese cabbage kimchi fractions also inhibited the DNA synthesis of the cancer cells. They inhibited the DNA synthesis of AGS human gastric adenocarcinoma cells more efficiently than that of HT 29 human colon adenocarcinoma cells. These results indicate that Chinese cabbage kimchi fractions show in vitro anticancer activity and the dichloromethane fr. among them reveals the highest effect.

• 공업화학
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• 제7권1호
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• pp.171-176
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• 1996

환경 친화성인 비이온 계면활성제 글루카마이드(N-알킬-N-아실 글루카민)는 크게 두 단계 반응으로 구분되는데, 첫 단계는 알킬 아민과 글루코스를 메탄올 용매하에 아민화 반응시킨 후, Ni 촉매하에 고압으로 환원시킨 결과 4종의 알킬 글루카민을 86~93%의 수율로 얻었다. 2단계 반응에서는 4종의 알킬 글루카민과 4종의 지방산 메틸 에스테르를 알칼리 촉매하에 메탄올을 환류시키면서 합성한 결과 16종중 12종의 글루카마이드는 84~95%수준의 높은 수율을 보였으나, 알킬기가 벤질일 경우에는 50~70%의 낮은 수율을 나타내었다. 알킬 글루카민 4종과 글루카마이드 16종에 대한 분자구조 확인은 IR, MS, NMR로 확인하였다.