• Membrane Journal
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• v.18 no.2
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• pp.138-145
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• 2008

A series of anion exchange composite membranes were prepared and characterized for electro-dialysis process used in the removal of toxic anion and cation polutants in groundwater or wastewater. The membranes were prepared as follows; first, porous poly(ethylene) (PE) substrates were fully impregnated with monomer mixtures with various ratio of vinylbenzylchloride (VBC), divinylbenzene (DVB) and ${\alpha},\;{\alpha}$-azobis(isobutyronitrile) (AIBN). Second, they were thermally polymerized to yield crosslinked poly(VBC-DVB)/PE composite membranes. Finally, the membranes were treated in trimethylamine (TMA)/acetone to give $-N^+(CH_3)_3$-containing poly(VBC-DVB)/PE membranes. The basic membrane properties such as ion exchange capacity (IEC), electric resistance and water content of the resulting membranes were measured as a function of VBC/DVB and TMA/Acetone content. As a result, the composite membranes showed lower electric resistance, lower water content and higher IEC than commercial anion exchange membranes (AMX, Astom) due to thin PE substrates, indicating that the composite membranes could be successfully applied to the electrodialysis for water treatment.

• Membrane Journal
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• v.27 no.4
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• pp.336-343
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• 2017

These days, the quality of indoor air is a very important concept for modern people who have lived in building and is a matter of new thinking. The quality is determined by the temperature and humidity of indoor air. In addition, there is a disadvantage in that energy consumption is severe for indoor air improvement. Therefore, researches on methods to solve such problems using total heat exchange have been actively conducted. So, in this study, aminated poly(styrene-ethylene-butylene-styrene) polymers were synthesized by introducing a hydrophilic substituent, ammonium, into main chain and the properties of synthesized polymers were evaluated. The synthesis was carried out through chloromethylation and amination reactions to introduce ammonium into main chain. As a result, the water uptake and the ion exchange capacity of the synthesized polymers increased as the content of the reaction reagent solution increased. It was confirmed that the important data at the total heat exchange membrane, water vapor transmission rate also increased according to temperature, equivalent.

• Polymer(Korea)
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• v.32 no.4
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• pp.347-352
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• 2008

High impact polystyrene (HIPS) nanocomposites with organically modified montmorillonite (organoclay) via in situ polymerization were synthesized, and the effects of organoclay incorporation on material properties were investigated. Organoclays having a reactive group, vinylbenzyltrimethyl clay (VBC) and octadecylvinylbenzyldimethyl clay (ODVC), were prepared by the ion-exchange reactions of sodium montmorillonite with vinylbenzyltrimethyl ammonium chloride (VBTMAC) and octadecylvinylbenzyldimethyl ammonium bromide (ODVBDAB), respectively, and a commercial organoclay, $Cloisite^{(R)}$ 10A(C10A), was used for comparison. It was confirmed that the X-ray diffraction (XRD) peak of the nanocomposites prepared by ODVC disappeared, which indicates the exfoliation of silicate layers. On the contrary, the XRD peak of the nanocomposites prepared by C10A shifted to lower angle, indicative of the intercalation of polymer chains into silicate layers. Rheological properties such as storage modulus and complex viscosity increased with increasing organoclay.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.535-538
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• 2000

Human leptin is a 16 kDa (146 amino acids) protein secreted from adipocytes and influences body weight homeostasis. In this report, active human leptin was successfully produced in the culture medium of Bacillus subtilis. After simple purification steps consisting of ammonium sulfate precipitation and anion-exchange column chromatography, 2.3 mg of leptin with a purity of greater than 95% was obtained from the 0.5 L culture with the recovery yield of 54.9%. The purified leptin showed the correct folding structure with one disulfide bond.

• KSBB Journal
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• v.13 no.5
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• pp.535-539
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• 1998

The monellin, a sweet-taste protein, was expressed and secreted in Saccharomyces cerevisiae. The secreted menellin was concentrated using an ultrafiltration membrane with a nominal molecular weight cut off of 3,000 or by ammonium sulfate precipitation. The monellin was purified by G-25 gel filtration chromatography, followed by CM-Sepharose ion exchange chromatography. The purified monellin was characterized by SDS-PAGE (SDS-Polyacrylamide Gel Electrophoresis) and PHLC. The molecular weight of monellin was found to be 10,700 dalton, and its purity was over 95%.

• Toxicological Research
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• v.4 no.2
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• pp.143-149
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• 1988

Cytolysin produced by Vibrio vulnificus ATCC 27562 was partially purified by sequential ammonium sulfate precipitation, gel filtration with Sephadex G-200, and ion exchange chromatography with DEAE-Sephadex. The partially purified cytolysin was inactivated by cholesterol. More than one molecule of the cytolysin was required to lyse a single erythrocyts. The antiserum against cytolysin enhanced the survival ratio of mice infected with low dose of V. vulnificus.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.81-81
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• 1993

Reverse transcriptase가 유도되는 것을 SDS-PAGE 및 효소활성 분석으로 확인할 수 있었으며 효소의 정제를 위한 예비실험으로 ammonium sulfate 및 DEAE cellulose ion exchange chromatorgraphy를 시행하였을 때 specific activity의 증가를 보여주므로서 reverse transcriptase의 분자클로닝 후 발현된 효소가 활성을 갖고 있음을 알 수 있었다. pMAL; cRI 재조합 유전자에 있는 protease의 유전자 발현을 유도했을 때 E. coli세포의 성장에 toxic하게 작용함을 관찰할 수 있었다. 이는 발현된 protease가 E. coil의 번식에 영향을 주는 것으로 믿어지며 Protease의 유전자 발현을 위한 host의 선택, inducer의 첨가시간 등 실험조건의 확립이 필요할 것으로 사료된다.

• Journal of the Korean Applied Science and Technology
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• v.14 no.3
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• pp.97-101
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• 1997

An intracellular, soluble 1,4-benzoquinone reductase was purified from Baker's Yeast by ammonium sulfate precipitation, DEAE-Sephacel anion exchange chromatography, and Sephacryl S-200 gel filtration chromatography. 1,4-Benzoquinone reductase was achieved 123.8 fold purification from crude homogenate with a yield of 11.1%.

• Environmental Analysis Health and Toxicology
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• v.1 no.1
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• pp.77-80
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• 1986

Radiochemical synthesis of $N^{G}$-mono［$^{14}$ C-methyl］-L-arginine is described. The compound was synthesized from radio-active mono［$^{14}$ C］-methylamine as easily and purified by strong cation-exchange resin (NH form) liquid chromatography using a gradient of ammonium hydroxide, and crystallized as flavianate. The free amino acid was successfully prepared by strirring its flavianate and strong anion-exchange resin (OH- form), which could remove the flavianic acid from its salt in water below room temperature. Purity of the compound was tested by thin-layer chromatography, thin-layer electro-phoresis, and scintillation spectrometry.y.

• BMB Reports
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• v.28 no.4
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• pp.306-310
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• 1995

A Mono Q HR 5/5 anion-exchange column with a FPLC system was used to separate exogenously expressed calmodulin from endogenous tobacco calmodulins. Transgenic tobacco calmodulins were purified by fractionation with ammonium sulfate, precipitation with sulfuric acid and hydrophobic chromatography on phenyl-Sepharose CL-4B. The purified calmodulins were chromatographed in the FPLC using the column. This method was selected because of the slight differences in the net charge of foreign and endogenous plant calmodulins due to amino acid sequence differences. By this approach, the exogenously expressed calmodulin was isolated from endogenous tobacco calmodulins. The isolated calmodulin was characterized by amino acid composition analysis as well as methylation analysis.