• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.108-108
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• 2002

포유동물의 암컷 생식기관에 존재하는 다양한 종류의 matrix metallo-proteinase (MMP)는 난소와 자궁의 구성성분의 주기적인 변화를 조절하며 이중 난소의 MMP는 난포의 성장과 배란 그리고 퇴화 동안 조직재구성에 매우 중요한 역할을 한다고 알려져 있다. 본 실험에서는 근래에 새로 발견된 사람의 난포액에 존재하는 분자량 약 110kDa인 MMP-2 isoform GA110을 동정하고 자 하였다. 난포액으로부터 GA110 단백질을 분리하기 위하여 난포액에 5mM ethylenediaminetetraacetic acid(EDTA)를 처리한 후 DEAE Sepharose Fast Flow를 이용한 chromatography를 시행하였다. 그 결과, 난포액 단백질들은 0.2M NaCl 의 분획에서 GA110 활성을 나타내었고 anti-human MMP-2 antibody에 대한 면역반응도 뚜렷이 나타났다. DEAE Sepharose Fast Flow에서 얻은 분획 중 GA110의 활성과 면역반응을 모두 나타내는 분획만을 모아 Gelatin Sepharose 4B affinity chromatography로 다시 분리하였다 분리한 결과 resin에 흡착된 단백질 (eluate) 분획들에서 매우 뚜렷한 GA110 gelatinase 활성을 나타내었으며 면역반응 또한 관찰되었다. 이 분획들의 단백질을 농축한 후 zymography를 시행하여 나타난 GA110 단백질 band를 잘라 내었으며 이로부터 단백질을 electroelution하여 농축한 후 reducing agent인 2-mercaptoethanol를 처리하였다. 이를 전기영동 후 MMP-2 (propeptide region) antibody를 사용하여 immunoblotting 한 결과 70-72kDa의 단백질만이 면역반응을 나타내었다. 마지막으로 위와 같이 준비된 70-72kDa 단백질의 아미노산 서열을 Edman degradation 방법으로 분석하였다. 그 결과 이 단백질의 N 말단의 10개의 아미노산 배열 순서가 알려진 사람의 proMMP-2의 전체 배열순서 중 propetide domain의 N 말단에서부터 다섯 번째에서 시작하여 10개의 아미노산의 서열과 정확하게 일치하였다. 위 결과들로 미루어 사람의 난포액에 존재하는 MMP-2의 새로운 isoform인 GA110은 70-72kDa의 ProMMP-2가 disulfide bond를 통해 homodimer 구조를 이루고 있는 것으로 여겨진다.

• Journal of the Korean Society for Heat Treatment
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• v.12 no.3
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• pp.221-230
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• 1999

The surface nitrogen permeation of Al alloyed 0.14%C-13%Cr stainless steels was investigated after heat treating at $1050^{\circ}C{\sim}1150^{\circ}C$ in the nitrogen gas atmosphere. The strong affinity between Al and nitrogen permeates the nitrogen through the interior of the steels. Two precipitates of round type and needle type are observed at the surface layer. These precipitates mainly consist of AlN containing plenty of aluminum. The surface layer of 0.53%Al alloyed specimen shows ferrite phase, while the surface layers of 1.65%Al and 2.27%Al alloyed specimens appear ${\gamma}$ plus ${\alpha}$ phases. The depth of nitrogen permeation depends upon the Al content and microstructure of the matrix. The 1.65%Al alloyed specimen representing ${\alpha}+{\gamma}$ matrix phases at the nitrogen permeation temperature shows the maximum case depth in this experiment. Although the surface hardness increases by raising the Al content of the specimen owing to the increase of nitride precipitation density, the nitride precipitation deteriorates the corrosion resistance in the solution of HCl, $H_2SO_4$, and $FeCl_3$.

• Structural Engineering and Mechanics
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• v.86 no.4
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• pp.487-501
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• 2023

Nanoparticles have lower size and larger specific surface area, good stability and less toxic and side effects. In recent years, with the development of nanotechnology, its application range has become wider and wider, especially in the field of biomedicine, which has received more and more attention. Bone defect repair materials with high strength, high elasticity and high tissue affinity can be prepared by nanotechnology. The purpose of this paper was to study how to analyze and study the composite materials for sports bone injury based on multifunctional nanomaterials, and described the electrospinning method. In this paper, nano-sized zirconia (ZrO₂) filled micro-sized hydroxyapatite (HAP) composites were prepared according to the mechanical properties of bone substitute materials in the process of human rehabilitation. Through material tensile and compression experiments, the performance parameters of ZrO₂/HAP composites with different mass fraction ratios were analyzed, the influence of filling ZrO₂ particles on the mechanical properties of HAP matrix materials was clarified, and the effect of ZrO₂ mass fraction on the mechanical properties of matrix materials was analyzed. From the analysis of the compressive elastic modulus, when the mass fraction of ZrO₂ was 15%, the compressive elastic modulus of the material was 1222 MPa, and when 45% was 1672 MPa. From the analysis of compression ratio stiffness, when the mass fraction of ZrO₂ was 15%, the compression ratio stiffness was 658.07 MPa·cm³/g, and when it was 45%, the compression ratio stiffness is 943.51MPa·cm³/g. It can be seen that by increasing the mass fraction of ZrO₂, the stiffness of the composite material can be effectively increased, and the ability of the material to resist deformation would be increased. Typically, the more stressed the bone substitute material, the greater the stiffness of the compression ratio. Different mass fractions of ZrO₂/HAP filling materials can be selected to meet the mechanical performance requirements of sports bone injury, and it can also provide a reference for the selection of bone substitute materials for different patients.

• Elastomers and Composites
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• v.43 no.4
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• pp.221-229
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• 2008

Starch as matrix polymer was used to do graft copolymerization with 2-ethylhexylacrylate, methyl methacrylate and acrylic acid. The polymerization was carried out by radical emulsion polymerization with increasing contents of starch. When 0.174% of $\alpha$-amylase as enzyme for starch was added, it was found that it made the best stable emulsion. The glass transion temperature of the polymerized material was increased with starch contents. The particle size and viscosity of the emulsion increased with starch contents due to the increased hydroxy group. Peel strength also increased with contents of starch because the enhanced hydroxy group caused to increase affinity between substrate surface and polymer materials. However, the initial tackiness decreased with starch contents owing to film hardness by higher glass transion temperature.

• KSBB Journal
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• v.30 no.6
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• pp.296-301
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• 2015

Eggshell-based biocomposites have become attractive due to their exquisite nanostructure and biological properties, which are mainly composed of highly organized calcium carbonate crystals controlled by organic macromolecules such as proteins and polysaccharides. Here, we designed the recombinant fusion protein of a putative eggshell matrix protein named as GG1234 and a fluorescent reporter protein of DsRed. The protein was successfully over-expressed in E. coli and purified by Ni-NTA affinity chromatography. In vitro calcium carbonate crystallization was conducted in the presence of the fusion protein, and morphological change was investigated. The protein inhibited the calcite growth in vitro, and spherical calcium carbonate micro-particles with the diameter of about $20-30{\mu}m$ were obtained. We expect that this study would be helpful for better understanding of eggshell-based biomineralization.

• International Journal of Industrial Entomology and Biomaterials
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• v.6 no.2
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• pp.151-155
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• 2003

Using gel filtration chromatography, high molecular silk fibroin with high purity was obtained and silk flbroin microsphere particles (SFMP) could be simply made by spray dryer method. Also, some of the physicochemical properties of SFMP and morphology were investigated. The average molecular weight of pure silk fibroin protein dissolved in calcium chloride is about 61,500g/㏖ as measured by gel permeation chromatography. SFMP was spherical in shape, and particles, sized average of 2 ${\pm}$ 10 ${\mu}$, were observed by SEM and particle analyzer, respectively. Obtaining microspheres particles by spray dryer method accelerated the transition from the random coil to the $\beta$-sheet structure during spray dryer treatment. It was identified by the basic fourier transform infrared spectroscopy of SFMP. The swelling ratio of SFMP is majorly dependent on the pH of the solution, not on the occurred gelation. The characteristic structure, which might be applicable to immobilization of drugs is superior to other matrix materials for the use of biomaterials with skin affinity.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.437-438
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• 2011

Spectral segmentation is a major trend in image segmentation. Specially, constrained spectral segmentation, inspired by the user-given inputs, remains its challenging task. Since it makes use of the spectrum of the affinity matrix of a given image, its overall quality depends mainly on how to design the graphical model. In this work, we propose a sparse, multi-layer graphical model, where the pixels and the over-segmented regions are the graph nodes. Here, the graph affinities are computed by using the must-link and cannot-link constraints as well as the likelihoods that each node has a specific label. They are then used to simultaneously cluster all pixels and regions into visually coherent groups across all layers in a single multi-layer framework of Normalized Cuts. Although we incorporate only the adjacent connections in the multi-layer graph, the foreground object can be efficiently extracted in the spectral framework. The experimental results demonstrate the relevance of our algorithm as compared to existing popular algorithms.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.12
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• pp.5507-5528
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• 2016

In computer vision, salient object is important to extract the useful information of foreground. With active contour analysis acting as the core in this paper, we propose a bottom-up saliency detection algorithm combining with the Bayesian model and the global color distribution. Under the supports of active contour model, a more accurate foreground can be obtained as a foundation for the Bayesian model and the global color distribution. Furthermore, we establish a contour-based selection mechanism to optimize the global-color distribution, which is an effective revising approach for the Bayesian model as well. To obtain an excellent object contour, we firstly intensify the object region in the source gray-scale image by a seed-based method. The final saliency map can be detected after weighting the color distribution to the Bayesian saliency map, after both of the two components are available. The contribution of this paper is that, comparing the Harris-based convex hull algorithm, the active contour can extract a more accurate and non-convex foreground. Moreover, the global color distribution can solve the saliency-scattered drawback of Bayesian model, by the mutual complementation. According to the detected results, the final saliency maps generated with considering the global color distribution and active contour are much-improved.

• Journal of the Korean Ceramic Society
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• v.51 no.4
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• pp.283-288
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• 2014

PdO-doped $BaZr_{0.85}Y_{0.15}O_{3-\delta}$ (BZPY) proton conductors have been proposed as applicable for intermediate temperature electrolytes for protonic ceramic fuel cells (PCFCs) because the PdO doping is effective for improving the proton conductivity of $BaZr_{0.85}Y_{0.15}O_{3-\delta}$ (BZY) with high affinity for hydrogen. In order to further improve the conductivity of BZPY, two-phase composite electrolytes consisting of a BZPY and molten carbonate were designed. Dense BZPY-based composite electrolytes were fabricated after sintering at $670^{\circ}C$ for 4 h, since molten carbonates fill the grain boundary of the porous BZPY matrix. Furthermore, BZPY/$(Li-0.5Na)_2CO_3$ composites show a significantly enhanced protonic conductivity at intermediate temperatures. This may be because easy proton transport is possible through the interface of the carbonate and oxide phase.

• The Korean Journal of Mycology
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• v.11 no.3
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• pp.109-114
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• 1983

${\beta}-Galactosidase$ activity of Aspergillus phoenicis was studied using ONPG and lactose as substrate. It increased monotonically during the exponential growth phase and dropped rapidly at the beginning of the stationary one. It exhibited high tolerable temperature and acidic optimal pH which provides certain advantages from the industrial view point. Enzyme of ${\beta}-galactosidase$ had more subsrate affinity for ONPG than for lactose and its apparent maximum activity was also higher with the former as substrate. Activity of this enzyme depended upon the conditions of immobilization. Optimum crosslinking reaction was occurred at pH 7.2 and 0. 35 vol. % of glutaraldehyde concentration.