• 대한화학회지
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• 제50권3호
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• pp.224-231
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• 2006

소재로 제조된 다공성 지지체의 기계적 물성 향상을 위해서 사용되는 가교제는 세포독성으로 인해 지지체의 생체적합성을 저하시킨다. 본 연구에서 키토산, 알지네이트 및 젤라틴으로 제조된 다공성 지지체는 가교제를 사용하지 않고 열처리에 의해 가교시키고, 가교된 다공성 지지체의 물성을 조사하였다. FT-IR분광분석을 통해 열처리된 다공성 지지체의 가교는 고분자 쇄간의 아미드 또는 에스테르 결합에 의해 형성되었음을 확인하였다. 열처리 다공성 지지체는 100~200m크기의 연결된 공극 구조를 형성하였고, 가교제 처리 다공성 지지체에 비해 수분 흡수력은 2배 이상 향상되었다. 열처리 다공성 지지체의 인장강도는 가교하지 않은 다공성 지지체에 비해 130% 이상 향상되었고, 최대 신장률은 가교처리 다공성 지지체보다 11.3% 향상되었다. 따라서 열처리로 물성을 증가시킨 천연고분자 소재의 다공성 지지체는 생체적합성이 우수한 조직공학용 지지체로서 유용하다.

• BMB Reports
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• 제33권2호
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• pp.133-137
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• 2000

To elucidate the effect of oxygen radicals on the molecular properties of proteins, the secondary and tertiary structure and molecular weight size of BSA and ${\beta}$-lactoglobulin were examined after irradiation of proteins at various doses. Gamma-irradiation of protein solutions caused the disruption of the ordered structure of protein molecules as well as degradation, cross-linking, and aggregation of the polypeptide chains. As a model system, BSA and ${\beta}$-lactoglobulin were used as a typical ${\alpha}$-helical and a ${\beta}$-sheet structure protein, respectively. A circular dichroism study showed that the increase of radiation decreased the ordered structure of proteins with a concurrent increase of aperiodic structure content. Fluorescence spectroscopy indicated that irradiation quenched the emission intensity excited at 280 nm. SDS-PAGE and a gel permeation chromatography study indicated that radiation caused initial fragmentation of proteins resulting in a subsequent aggregation due to cross-linking of protein molecules.

• Journal of Microbiology and Biotechnology
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• 제8권4호
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• pp.416-421
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• 1998

A carboxyl group modifier, l-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) was used to study the interactions between three components of toluene dioxygenase (TDO) from Pseudomonas putida FI. $Ferredoxin_{TOL}$ activity was increased by the treatment with EDC; however, the activity was rapidly declined in the prolonged incubation. In covalent cross-linking experiments with EDC, $Ferredoxin_{TOL}$ made a one-to-one complex with $Reductase_{TOL}$ or the large subunit of $ISP_{TOL}$. These results provide evidence for the involvement of electrostatic interactions in the TDO electron transfer system.

• BMB Reports
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• 제35권6호
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• pp.590-594
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• 2002

To elucidate the effect of gamma-irradiation on the molecular properties of myoglobin, the secondary and tertiary structures, as well as the molecular weight size of the protein, were examined after irradiation at various irradiation doses. Gamma-irradiation of myoglobin solutions caused the disruption of the ordered structure of the protein molecules, as well as degradation, cross-linking, and aggregation of the polypeptide chains. A SDS-PAGE study indicated that irradiation caused initial fragmentation of the proteins and subsequent aggregation, due to cross-linking of the protein molecules. The effect of irradiation on the protein was more significant at lower protein concentrations. Ascorbic acid protected against the degradation and aggregation of proteins by scavenging oxygen radicals that are produced by irradiation. A circular dichroism study showed that an increase of the irradiation decreased the a-helical content of myoglobin with a concurrent increase of the aperiodic structure content. Fluorescence spectroscopy indicated that irradiation increased the emission intensity that was excited at 280 nm.

• 공업화학
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• 제30권6호
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• pp.643-651
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• 2019

Polybenzimidazole (PBI), an engineering polymer with well-known excellent thermal, chemical and mechanical stabilities has been recognized as an alternative to high temperature polymer electrolyte membranes (HT-PEMs). This review focuses on recent advances made on the development of PBI-based HT-PEMs for fuel cell applications. PBI-based membranes discussed were prepared by various strategies such as structural modification, cross-linking, blending and organic-inorganic composites. In addition, intriguing properties of the PBI-based membranes as well as their fuel cell performances were highligted.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1130-1131
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• 2015

팰릿 형태의 XLPE (Cross-Linking Polyethylene)를 Hot Press로 시험편을 제작하여 열분석 데이터 처리장치를 이용하여 시차 주사 열량법 (differential scanning calorimetry, DSC)과 열 중량 분석 (Thermo gravimetric analysis, TGA) 등으로 열적 특성을 분석하였다. 분석 결과, XLPE의 전이온도 피크는 $61^{\circ}C$, 용융온도에 해당하는 피크는 $102^{\circ}C$에서 나타났으며 XLPE의 TG 분석 결과 $470^{\circ}C$ 근처에서 한 번의 급격한 열중량 감소를 보였으며 $800^{\circ}C$까지 측정 후 잔류물은 완전 분해되어 거의 존재하지 않았음을 알 수 있었다.

• Food Science and Biotechnology
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• 제14권1호
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• pp.16-20
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• 2005

Additions of ground garlic, chili and ginseng powder did not affect the breaking force and strain of directly heated gel of Alaska pollack surimi. In comparison, these additives reduced the setting effect achieved by incubation of the salted surimi at $25^{\circ}C$, and resulted in a decreased breaking force and strain for the two step heated gel. Garlic almost completely inhibited the myosin cross-linking reaction, an important reaction for improving the gel properties occurring in the setting process. However, chili and ginseng powder minimally inhibited the cross-linking reaction. Thus, this study proposes that the mechanism for the suppression of the setting effect by chili and ginseng is different from that of garlic.

• Transactions on Electrical and Electronic Materials
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• 제11권2호
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• pp.69-72
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• 2010

This study investigates the thermal and mechanical properties of insulation elements through the mixing of epoxy based micro and nano particles. Regarding their thermal properties, differential scanning calorimeter and dynamic mechanical analyser were used to calculate the cross-linking densities for various types of insulation elements. The mechanical properties of the bending strength, the shape and scale parameters, were obtained using the Weibull plot. This study obtained the best results in the scale parameters, at 0.5 phr, for the bending strength of the epoxy nano-and-micro mixture composites.

• Restorative Dentistry and Endodontics
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• 제37권1호
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• pp.2-8
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• 2012

The limited durability of resin-dentin bonds severely compromises the longevity of composite resin restorations. Resin-dentin bond degradation might occur via degradation of water-rich and resin sparse collagen matrices by host-derived matrix metalloproteinases (MMPs). This review article provides overview of current knowledge of the role of MMPs in dentin matrix degradation and four experimental strategies for extending the longevity of resin-dentin bonds. They include: (1) the use of broadspectrum inhibitors of MMPs, (2) the use of cross-linking agents for silencing the activities of MMPs, (3) ethanol wet-bonding with hydrophobic resin, (4) biomimetic remineralization of water-filled collagen matrix. A combination of these strategies will be able to overcome the limitations in resin-dentin adhesion.

• 한국식품저장유통학회:학술대회논문집
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• 한국식품저장유통학회 2003년도 제23차 추계총회 및 국제학술심포지움
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• pp.135.1-135
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• 2003

To elucidate the effect of gamma-irradiation on the molecular properties of hemoglobin, the secondary, tertiary structure, and the molecular weight size of the protein were examined after irradiation at 0.5, 1, 5, and 10 kGy. Gamma-irradiation of hemoglobin solutions caused the disruption of the ordered structure of the protein molecules, as well as degradation, cross-linking, and aggregation of the polypeptide chains. A SDS-PAGE study indicated that irradiation caused initial fragmentation of the proteins and subsequent aggregation due to cross-linking of the protein molecules. The effect of irradiation on the protein was more significant at lower protein concentrations. Ascorbic acid decreased the degradation and aggregation of proteins by scavenging oxygen radicals that were produced by irradiation. A circular dichroism study showed that irradiation decreased the helical content of hemoglobin with a concurrent increase of the aperiodic structure content. Fluorescence spectroscopy indicated that irradiation decreased the emission intensity that was excited at 280 nm.