• Bulletin of the Korean Chemical Society
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• 제33권1호
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• pp.248-254
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• 2012

During the monolayer assembly of zeolite microcrystals using sonication with stacking (SS) method, the factors that govern the degree of close packing (DCP) between the microcrystals, the rate of attachment (rA) of microcrystals onto the substrate, the degree of coverage (DOC), and the binding strength (BS) between each crystal and the substrate were investigated for each mode of binding linkage (MBL). The tested MBLs were covalent linkage (CL), ionic linkage (IL), and polyelectrolyte-mediated ionic linkage (p-IL). Unlike the monolayers of zeolite crystals assembled on glass with a covalent linkage, the strong BS, very high DOC, and very high DCP do not decrease during monolayer assembly on glass through ionic linkages. This results indicate that the surface migration of crystals undergo linkage-nondestructively when crystals were attached to the substrates through ionic linkages.

• Journal of Microbiology and Biotechnology
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• 제11권1호
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• pp.17-20
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• 2001

Whole-cell attachment by covalent linkage, thereby simulating natural and specific attachments, improves the osmotolerance of Saccharomyces cerevisiae cells. The enhanced osmoresistance is correlated with a decrease in the intercellular concentration of trehalose and accompanied by membrane compositional changed. The results obtained indicate that yeast cell-support (physical) contact is sensed and responded to.

• 한국식품과학회지
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• 제29권2호
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• pp.320-325
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• 1997

이소말토올리고당의 생산에 사용되는 Aspergillus niger 유래의 TG의 고정화를 위해 여러가지 방법을 비교하여 고정화방법을 선정하였다. 이온결합과 흡착, entrapment, 공유결합과 금속이온을 이용한 결합 등을 이용하여 TG의 고정화를 시도하였다. TG의 고정화를 위해서는 수율면에서 우수하고(61.3%) 간편성도 있는 CNBr-activated sepharose 4B를 이용한 고정화 방법을 선정하였다. DEAE-sephadex를 이용한 이온결합에 의해서는 33.1%, Diaion HP-20를 이용한 흡착법에 의해서는 22.5%의 수율을 보였으나 CNBr-activated sepharose 4B를 이용한 고정화 방법에 비해 수율과 안정성이 낮아 제외하였다. Entrapment에 의한 고정화는 bead내의 확산저항으로 인해 최종산물의 생성에 불리한 것으로 판단되었고 magnesium silicate, silica gel, glass bead 등의 담체를 이용한 고정화방법은 낮은 수율로 인해, 금속이온을 이용한 경우 역시 낮은 수율과 장시간의 준비로 인해 고정화방법으로 부적당하다고 판단되었다.

• Archives of Pharmacal Research
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• 제20권5호
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• pp.396-403
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• 1997

In order to direct the form of the immune response in an antigen-specific manner, we constructed a fusion protein (OVA/IL12) that contained the T cell-dependent antigen, ovalbumin (OVA), covalently linked to murine interleukin-12 (IL-12). The OVA/IL12 protein was produced in a baculovirus expression system and was purified by anti-OVA immunoaffinity chromatography. The purified OVA/ILI2 protein displayed potent IL-12 bioactivity in an IL-12 proliferation assay. BALB/c mice immunized with the OVA/IL12 protein produced increased quantities of anti-OVA IgG2a antibody compared with mice immunized with recombinant OVA alone. Lymph node cells from the immunized mice with the OVA/IL12 protein produced large amounts of IFN-,Y when restimulated in vitro with OVA, while those from mice immunized with the OVA protein produced little or no IFN-.gamma.. In contrast, immunization with a mixture of OVA and free recombinant IL-12 also induced IFN-.gamma. production, which was not OVA-specific. These studies indicate that the OVA/IL12 fusion protein can induce OVA-specific, Th1-dominated immune responses, and that the covalent linkage of OVA and IL-12 confines the effect of IL-12 to OVA-specific cells.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.315.2-316
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• 2003

Polyethylenimine (PEI) has been used as a non-viral gene delivery carrier. To improve the efficacy of transfection, transferrin was incorporated by covalent linkage to PEI. As a model plasmid DNA, pHME185/b-gal, a mammalian expression vector was used. The transferrin-polyethylenimine (TfPEI) was synthesized by conjugate PEI with transferrin using sodium periodateand and characterized by FT-IR and 1H-NMR. (omitted)

• 한국진공학회:학술대회논문집
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• 한국진공학회 2002년도 제22회 학술발표회 초록집
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• pp.210-210
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• 2002

• Korean Chemical Engineering Research
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• 제44권3호
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• pp.254-258
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• 2006

휘발성 유기화합물을 제거하는 허니콤 흡착제의 제조 성분인 무기질 섬유에 흡착력이 뛰어난 제올라이트를 화학 결합시켰다. 무기질 섬유를 염산, 황산 또는 플루오르화 수소산 등으로 처리하여 표면의 불순물을 제거하여 제올라이트의 접합 능력을 향상시켰다. 무기질 섬유와 제올라이트의 표면에 매달은 클로로프로필, 아미노프로필 또는 에폭시기 등을 서로 반응시켜 두 물질을 화학 결합시켰으며, 연결 화합물로 고분자 폴리에틸렌이민을 사용하기도 하였다. 결합상태는 전자현미경으로 관찰하였고, BET 표면적 분석을 통하여 제올라이트 접합량을 유추하였다. 폴리에틸렌이민을 사용하면 제올라이트를 무기질 섬유에 많이 결합시킬 수 있었다.

• KSBB Journal
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• 제5권2호
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• pp.141-149
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• 1990

Aspergillus niger유래의 $\beta$-glucosidase를 (1)glutarald-ehyde를 가교제로 한 chitin과 chitosan담체에 covalent linkage (2)Amberite IRA93과 DEAE-cellulose담체에 succinylation시킨 후 흡착, 그리고 (3)alginarte, polyacry-lamide를 각종 가교제를 이용 entrapment등의 방법으로 고정화 하였다. Glutaraldehyde를 가교제로써 chitosan을 활성화시킨후 $\beta$-glucosidase를 고정화 시켰을때 효소활성 회수율이 31.5%로 가장 높았고, 또한 column형 반응기에서의 15일 경과 후 효소활성 유지도도 69%로서 가장 우수하였다. 또한 succinylation시킨 효소를 Amberite IRA93 담체에 흡착시켰을 때 효소활성 회수율은 24.7%였고 효소 활성유지도는 62%였다. 반면에 entra-pment 방법에 의한 $\beta$-glucosidase의 고정화는 효소의 계속적인 용출로 $\beta$-glucosidase의 고정화에는 적합하지 않았다. Chitosan담체에서의 고정화 최적조건을 조사한 결과 가교제인 glutaraldehyde의 최적농도는 0.4%였고, glutaraldehyde의 최적 반응 pH는 4.8이었다. 또한 column형 반응기를 이용하여 cellobiose로부터 glucose로의 전환율을 조사하여 고정화 효소의 효용성을 검토하였다.

• Journal of Microbiology and Biotechnology
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• 제1권1호
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• pp.54-62
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• 1991

Cyclodextrin glucanotransferase(CGTase) derived from Bacillus macerans was immobilized by (1) covalent linkage on chitosan and chitin with glutaraldehyde, (2) adsorption on DEAE-cellulose and Amberite IRA 900 after succinylation, and (3) entrapment on alginate and polyacrylamide by cross linking. Adsorption on Amberite IRA 900 and covalent linking on chitosan were identified to be the most suitable immobilization methods considering the yield of activity and stability of immobilized CGTase. The enzymatic properties of immobilized CGTase were investigated and compared with those of the soluble CGTase. Thermal stability of CGTase immobilized on chitosan was increased from 50 to $55^{\circ}C$, and the optimum temperature of CGTase immobilized on Amberite IRA 900 was shifted from 55 to $50^{\circ}C$. The effect of molecular size of soluble starch (substrate) on immobilized CGTase investigated using partially liquefied substrates with different dextrose equivalent(DE). Cyclodextrin(CD) conversion yield augmented according to the increase of DE level for immobilized CGTase on Amberite IRA 900. CD conversion yield of partially cyclized starch with soluble CGTase was higher compared with liquefied one with ${\alpha}-amylase$.

• Current Photovoltaic Research
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• 제5권2호
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• pp.43-46
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• 2017

Large absorption band shift has been observed for the azo-dye (disperse red-13, DR-13) attached on the surface of silica spheres. Urethane linkage has been utilized to form covalent bond between azo-dye (-OH) and 3-isocyanatopropyltriethoxysilane (ICPTES, -N=C=O). The synthesized ICPTES-DR-13 (ICPDR) molecules were attached to the silica spheres by the hydrolysis and condensation reaction. Although the absorption peak of DR-13 in methanol is at 510 nm, the absorption peak of the ICPDR-silica spheres shifts to 788 nm. The large absorption peak shift is due to the formation of intramolecular charge-transfer band with large aggregated ICPDR.