• 한국식품과학회지
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• 제27권5호
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• pp.753-756
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• 1995

아스파탐 전구체의 보다 효율적인 효소적 합성 방법을 개발하기 위하여 thermolysin의 고정화 방법을 확립하고자 고정화 담체로서 다공성 수지인 Amberlite XAD-7을, 가교화제로서 glutaraldehyde를 사용하여 최적 고정화 조건을 조사하고자 하였다. Thermolysin이 Amberlite XAD-7에 흡착되는 속도는 초기에 빠른 것으로 나타났으며, $5^{\circ}C$에서 24시간후는 96%가 흡착되었다. Thermolysin에 대한 Amberlite XAD-7의 최대흡착량은 수지 l당 340g 이상이었으며, 투입한 thermolysin 양이 300g일 때까지는 흡착된 양의 증가하는 관계는 직선관계를 보여주었다. thermolysin의 가교화를 위한 효과적인 pH와 glutaraldehyde의 농도, 가교화시간은 각각 $pH\;6.0{\sim}7.0,\;6{\sim}12.5%$ 및 $3{\sim}7$시간이었다. 특히 glutaraldehyde 6%에서는 7시간, 12.5%에서 3시간의 가교화가 효소의 잔존역가와 가교화 정도를 현저히 높였다. 이때의 잔존역가는 30% 이상인 것으로 나타났다.

• Journal of Pharmaceutical Investigation
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• 제36권2호
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• pp.83-87
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• 2006

Poly(acrylic acid) (PAA) was identified to possess good mucoadhesive properties ensuring its application to extend the retention times of the formulations at the oral cavity, intended route of administration using the polymer. In the noncross-linked state, PAA will swell and become eroded owing to the presence of salivary flow from the site of application. The formation of cross-links between the polymer chains will allow swelling but prevents the erosion of the dosage form. In the current study, cross-linking was achieved by esterification of the PAA chains with sucrose. The density of crosslinking was modified by changing sucrose concentration and the duration of cure time. The cross-linking density of the polymer hydrogel was assessed by equilibrium swelling studies. The mucoadhesion testing method allowed a comparative study of the hydrogels prepared. An inverse relationship between equilibrium swelling and peak detachment force showed that increased PAA chain density per unit area enhanced the mucoadhesive interaction.

• 한국재료학회지
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• 제32권4호
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• pp.186-192
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• 2022

Collagen is one of the most widely used biological materials in medical design. Collagen extracted from marine organisms can be a good biomaterial for tissue engineering applications due to its suitable properties. In this study, collagen is extracted from fish skin of Ctenopharyngodon Idella; then, the freeze drying method is used to design a porous scaffold. The scaffolds are modified with the chemical crosslinker N-(3-Dimethylaminopropyl)-N'-ethyl carbodiimide hydrochloride (EDC) to improve some of the overall properties. The extracted collagen samples are evaluated by various analyzes including cytotoxicity test, SDS-PAGE, FTIR, DSC, SEM, biodegradability and cell culture. The results of the SDS-PAGE study demonstrate well the protein patterns of the extracted collagen. The results show that cross-linking of collagen scaffold increases denaturation temperature and degradation time. The results of cytotoxicity show that the modified scaffolds have no toxicity. The cell adhesion study also shows that epithelial cells adhere well to the scaffold. Therefore, this method of chemical modification of collagen scaffold can improve the physical and biological properties. Overall, the modified collagen scaffold can be a promising candidate for tissue engineering applications.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제7권2호
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• pp.183-192
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• 2001

호스트-타겟으로 연결되는 내장형 시스템 개발 환경에서 호스트의 링커는 크로스 컴파일된 목적 화일을 타겟의 모듈들과 링킹하고 타겟을 다운로딩한다. 본 연구에서는 이와 같은 링커를 목적 화일 형식에 종속적인 모듈과 독립적인 모듈로 세분화하였다. 종속적인 모듈은 목적 화일로부터 화일 형식에 독립적인 링킹 정보를 추출하고, 독립적인 모듈은 이 링킹 정보로부터 실제적인 링킹을 담당한다. 이와 같은 세분화는 내장형 시스템 개발 환경에서 타겟 시스템에 대한 이식성을 높일 수 있다. 또한, 본 연구의 링커는 로딩되는 목적 화일 뿐만 아니라 이미 로딩된 타겟 모듈들에 대해서도 재배치를 적용하는 점진적 원격 링킹을 수행한다. 링커의 점진적 원격 링킹은 모듈 단위로 타겟으로 링킹할 수 있기 때문에 모듈들을 통합하여 타겟으로 링킹하는 방식 보다 링킹 시간을 단축할 수 있다. SPEC95 정수형 벤치마크 프로그램들에 대한 실험 결과 평균 64.90%의 감소율을 보였다. 또한, 링커의 점진적 원격 링킹은 사용자가 목적 화일들의 링킹 순서를 고려하지 않고 임의의 순서로 링킹할 수 있는 편의성을 제공할 수 있다. 현재, 본 연구의 링커는 상용화 준비 중인 내장형 응용 개발 환경 ESTO의 [1] 내부 모듈로 개발되었다.

• Journal of Microbiology and Biotechnology
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• 제27권3호
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• pp.552-560
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• 2017

Quorum quenching (QQ) bacteria entrapped in a polymeric composite hydrogel (QQ medium) have been successfully applied in membrane bioreactors (MBRs) for effective biofouling control. However, in order to bring QQ technology closer to practice, the physical strength and lifetime of QQ media should be improved. In this study, enforcement of physical strength, as well as an extension of the lifetime of a previously reported QQ bacteria entrapping hollow cylinder (QQ-HC), was sought by adding a dehydration procedure following the cross-linking of the polymeric hydrogel by inorganic compounds like $Ca^{2+}$ and boric acid. Such prepared medium demonstrated enhanced physical strength possibly through an increased degree of physical cross-linking. As a result, a longer lifetime of QQ-HCs was confirmed, which led to improved biofouling mitigation performance of QQ-HC in an MBR. Furthermore, QQ-HCs stored under dehydrated condition showed higher QQ activity when the storage time lasted more than 90 days owing to enhanced cell viability. In addition, the dormant QQ activity after the dehydration step could be easily restored through reactivation with real wastewater, and the reduced weight of the dehydrated media is expected to make handling and transportation of QQ media highly convenient and economical in practice.

• The Korean Journal of Physiology and Pharmacology
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• 제5권6호
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• pp.495-501
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• 2001

We have cloned the mouse neurotensin/neuromedin N (NT/N) gene from the murine mast cell line Cl.MC/C57.1 for the first time. The murine NT/N cDNA clone consisted of 765 nucleotides and coded for 169 peptide residues with an N-terminal signal peptide, and the C-terminal region contained of one copy of neurotensin (NT) and one copy of neuromedin N (NN). Total of four Lys-Arg dibasic motifs were present; one each at the middle of the open reading frame, at the N-terminal of NN, at the C-terminal of NT, and between NN and NT. Amino acid sequence analysis of the mouse NT/N revealed 90% homology to that of the rat NT/N gene. NT/N is expressed in murine mast cell lines (Cl.MC/C57.1 and P815), but not in murine bone marrow-derived mast cells (BMMCs), murine macrophage cell line (RAW 264.7), nor in murine T cell line (EL-4). NT/N mRNA in C1.MC/C57.1 is highly inducible by IgE cross-linking, phorbol myristate acetate, neurotensin, and substance P. Following the treatment of demethylating agent, 5-azacytidine (5-azaC), the NT/N gene was induced in BMMCs in response to IgE cross-linking. 5-azaC-treated BMMCs did not express the NT/N gene without additional stimuli. These findings suggested that the regulation of NT/N gene expression was dependent on the effects of not only gene methylation but also enhancer and/or repressor proteins acting on the NT/N promoter.

• Macromolecular Research
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• 제11권5호
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• pp.322-327
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• 2003

Two kinds of mutually cross-linkable copolymers were prepared to be used as humidity-sensing materials. The humidity-sensitive thin films consist of cross-linked polyelectrolytes of the following component: 4-vinylbenzyl dimethyl 2-(dimethylphosphino)ethyl phosphonium chloride (1)/ bis(2-methoxyethyl)itaconate (2)= 3/l, 2/l, 1/1 and 1/2 and 4-vinylbenzyl chloride (3)/ vinylbenzyl tributyl phosphonium chloride (4)= 3/l, 2/l, 1/1 and 1/2. The humidity sensor prepared from the reaction of 1/2= 2/l with 3/4= 2/l showed an average resistance of 723,36.2 and 2.42 ㏀ at 30, 60 and 90%RH, respectively. Temperature dependence, frequency dependence, and response time were measured and the reliability test such as water durability and long-term stability were also estimated.

• 한국응용과학기술학회지
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• 제36권1호
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• pp.305-311
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• 2019

높은 함수율을 갖는 소프트렌즈를 제조하기 위하여 아크릴계 공중합체를 설계, 제조하였다. 공중합체용 모노머로 2-hydroxyethyl methacrylate(HEMA)를 사용하였고 가교제로는 ethylene glycol dimethacrylate(EGDMA), glycerol dimethacrylate(GD) 혹은 glycerol 1,3-diglycerolate diacrylate(GDD)를 이용하여 렌즈를 제조하였다. 함수율 측정결과, 고함수율 렌즈는 기존의 36%에서 46%로 높게 나타났으며 접촉각도 38.6 에서 34.4 로 낮아져 표면 친수성이 높게 나타남을 확인하였다. 인장강도는 가교제의 친수성이 증가함에 따라 0.1MPa 에서 0.08 그리고 0.05 로 감소하였고 전자현미경으로 렌즈의 단면을 확인한 결과 상분리 현상은 나타나지 않았다. 광중합은 Real-time infrared(RTIR)로 측정하였는데 초기 중합 속도가 가교제에 따라 0.6 에서 0.9 로 나타났다.

• KSBB Journal
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• 제21권1호
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• pp.16-19
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• 2006

최근의 연구에 의하면 열이나, 산화적 스트레스에 대해서 NDPK는 구조적인 변화를 유발하며, 효소 활성과 구조가 oxidant에 의해 변화된다는 보고를 근거로 하여 정상적인 효모균주와 효모의 NDPK 유전자가 파괴된 mutant에서, 산화적 스트레스에 관련된 역할을 규명하고자 2-D 전기영동 방법을 통해서, $H_2O_2$의 처리전과 처리 후에 전사패턴이 변화된 유전자들, 즉, 산화적조절 신호체제에 연관되어졌을 것이라고 생각되어지는 몇 개의 단백질 리스트를 얻었다. 이 결과는 NDPK의 redox state의 조절에 관련된 효소의 성질을 규명함에 있어 유용한 유전자 신호 체제정보를 제공할 것으로 생각되어진다.

• 공업화학
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• 제30권5호
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• pp.562-568
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• 2019

Cylindrical shape extrudates of calcium silicate hydrate (CSH) were prepared using different percentages of polyvinyl alcohol (PVA) / sodium alginate (SA) mixtures as binders and an aqueous solution containing 6% $H_3BO_3$ and 3% $CaCl_2$ was used as a cross linking agent. As the quantity of alginate increases, the phosphate removal efficiency and capacity were decreased. Among four different extrudate samples, the sample prepared by 8% PVA + 2% SA showed the highest phosphate removal efficiency (59.59%) and capacity (29.97 mg/g) at an initial phosphate concentration of 100 ppm and 2.0 g/L adsorbent dosage. Effects of the adsorbent dosage, contact time and initial phosphate concentration on the sample were further studied. The removal efficiency and capacity obtained by a 4.0 g/L adsorbent dose at an initial phosphate concentration of 100 ppm in 3 h were 79.38% and 19.96 mg/g, respectively. The experimental data of kinetic and isotherm measurements followed the pseudo-second-order kinetic equation and Langmuir isotherm model, respectively. These results suggested that the phosphate removal was processed via a chemisorption and a monolayer coverage of phosphate anions was on the CSH surface. The maximum adsorption capacity ($q_{max}$) was calculated as 23.87 mg/g from Langmuir isotherm model.