• Elastomers and Composites
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• v.45 no.2
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• pp.80-86
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• 2010

Carbon nanotubes (CNTs) exhibit excellent mechanical, electrical, and magnetic properties as well as nanometer scale diameter and high aspect ratio, which make them an ideal reinforcing agent for high strength polymer composites. The functionalized CNTs are believed to be very promising in the fields such as preparation of functional and composite materials. CNT-Polymer composites are expected to have good processability characteristics of the polymer and excellent functional properties of the CNTs. However, since CNTs usually form stabilized bundles due to Van der Waals interactions, are extremely difficult to disperse and align in a polymer matrix. The biggest issues in the preparation of CNT-reinforced composites reside in efficient dispersion of CNTs into a polymer matrix, and the alignment and control of the CNTs in the matrix. There are several methods for the dispersion of nanotubes in the polymer matrix such as solution mixing, bulk mixing, melt mixing, in-situ polymerization and chemical functionalization of the carbon nanotubes, etc. These methods and preparation of high performance CNT-polymer composites are described in this review.

• Journal of Life Science
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• v.2 no.4
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• pp.220-231
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• 1992

항체의 구조와 기능, 촉매항체의 이론적 배경과 방법론에 대하여, 특히 에스테르-아미드결합의 가수분해반응을 중심으로 기술하였다. 항체단백질은 분자량이 약 150kDa이며, 2가닥의 L사슬과 2가닥의 H사슬로 구성되어있다. 항체에 촉매작용을 도입하는 연구가 행해지고 있는데 대표적인 방법은 hapten에 대한 항체의 입체적 또는 전자적 상보성은 이용하는 것이고 둘째는 기질 특이적인 항체를 직접 화학수식 하든가 또는 부위 특이적 변이유발 등의 방법으로 촉매활성기를 도입하는 방법이다. 촉매항체의 매력은 합리적인 hapten의 설계로 원하는 촉매활성을 갖는 항체를 유도하는 데 있다.

• Korean Chemical Engineering Research
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• v.60 no.3
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• pp.398-406
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• 2022

The outer membrane of Gram-negative bacteria is the outermost layer of cellular environment in which numerous biophysical and biochemical processes are in action sustaining viability. Advances in cell engineering enable modification of bacterial genetic information that subsequently alters membrane physiology to adapt bacteria to specific purposes. Surface display of a functional molecule on the outer membranes is one of strategies that directs host cells to respond to a specific extracellular matter or stimulus. While intracellular expression of a functional peptide or protein fused to a membrane-anchoring motif is commonly practiced for surface display, the method is not readily applicable to exogenous or large proteins inexpressible in bacteria. Chemical conjugation at reactive groups naturally occurring on the membrane might be an alternative, but often compromises fitness due to non-specific modification of essential components. Herein, we demonstrated two distinct approaches that enable site-specific decoration of the outer membrane with a fluorescent agent in Escherichia coli. An unnatural amino acid genetically incorporated in a surface-exposed peptide could act as a chemoselective handle for bioorthogonal dye labeling. A surface-displayed α-helical domain originating from a part of a selected heterodimeric coiled-coil complex could recruit and anchor a green fluorescent protein tagged with a complementary α-helical domain to the membrane surface in a site- and hetero-specific manner. These methods hold a promise as on-demand tools to confer new functionalities on the bacterial membranes.

• Applied Chemistry for Engineering
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• v.28 no.1
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• pp.125-131
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• 2017

We report organically functionalized Ag nanoparticles spontaneously form two-dimensional (2D) novel superstructures at the air-water interface. Analysis of the superstructures suggests that the 2D assembly of Ag nanoparticles originates from a subtle interplay between characteristic inter-particle interactions that can be readily controlled by changing the sizes of nanoparticle metal core and surfactants. Such structures have potential uses in nanostructured functional materials, catalysis, and device applications.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.44 no.4
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• pp.419-425
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• 2018

In this study, cross-linked collagen gels were successfully prepared with varying of elastic modulus from 0.7 to 17.7 kPa using a chemical cross-linker. Then, human dermal fibroblasts were encapsulated into the porous pores introduced into the gels, and cell growth and behavior were examined by gel's mechanical properties. Specifically, increasing elastic modulus of the gel led to decreases in procollagen synthesis from 47 to 32 ng. In addition, there could be optimum elastic modulus for procollagen production, when the gels were treated with adenosine. However, interestingly, this study discovered that the procollagen production level was not influenced by the elastic modulus of the gel for functional peptide. In conclusion, these results would be highly useful for designing reconstructed skins with varying of elastic modulus to examine functional materials in cosmetics.

• Journal of Food Hygiene and Safety
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• v.2 no.2
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• pp.75-81
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• 1987

Bifunctional monoterpene 유도체의 향의 유무는 분자내에 존재하는 두 개의 관능기인, proton donor(AH)와 proton acceptor(B)가 olfaction과 구조활성 상호작용(SAR)과 밀접한 관계가 있다. 일반적으로 Ohloff가설에 의하면, p-menthane monoterpene 분자내의 AH와 B의 입체배위적 최소거리가 3${\AA}$ 이하인 경우 향을 갖고, 3${\AA}$ 이상인 경우는 향을 갖지 않는다. Bifunctional pinanone, thujane, carane, carvomenthone 및 기타 menthone 유도체 등을 이용하여 이 가설을 확대 연구하였다. Bifunctional monoterpene인 (원문이미지참조) 등은 분자내에 각각 AH (OH 혹은 COOH)와 B (C=O)의 입체배위적 최소 거리가 항상 3${\AA}$ 이하여서 향을 가지며, 이들은 olfactory three point attachment에 의한 구조활성 상관관계를 가지는 것으로 사료된다. 상기 화합물의 proton donor인 OH, 혹은 COOH가 각각 acetylation이나 methylation되는 경우에는 proton donor로서의 기능 상실로 향이 사라지게 되었다.

• Food Science of Animal Resources
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• v.23 no.2
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• pp.128-136
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• 2003

This study was peformed to evaluate physico-chemical and textural properties, and shelf-life effect of low-fat functional sausages(LFFS) manufactured with sodium lactate(SL), lac color and various molecular weights of chitosans(low=1.5 kDa, medium=30∼40 kDa and high=200 kDa) during storage at 4$^{\circ}C$ for 8 weeks. LFFS had a pH range of 6.39∼6.50, 76∼78% moisture, <2% fat, 14∼15% protein. The combination of SL and low molecular weight(MW) of chitosan improved water holding capacity(WHC), however those of SL and medium MW of chitosan reduced WHC. Vacuum purge(VP) reduced with increased MW of chitosans during refrigerated storage. The addition of chitosans reduced the lightness and yellowness, but increased the redness values, which was comparable to the sodium nitrite concentration between 75 and 150 ppm. LFFS containing SL and medium MW of chitosan increased most texture profile analysis(TPA) values, as compared to controls with 75 and 150 ppm. The addition of SL in LFFS retarded the microbial growth for Listeria monocytogenes, however no synergistic effect with the addition of chitosans were observed. E coli O157:H7 and Salmonella typhimurium reduced during refrigerated storage, regardless of SL and chitosan treatments. Increased storage time increased values for VP, yellowness and textural properties. These results indicated that the combination of SL and various MW of chitosans affected the functional and textural properties, and inhibited the microbial growth for LM effectively. In addition, 0.5% lac color as a replacer for sodium nitrite improved the color development, resulting in similar hunter color values, which was comparable to the sodium nitrite concentration between 75 and 150 ppm.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.5
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• pp.519-523
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• 2002

Soluble polysaccharide (SP) from green layer, Enteromorpba prolifera was extracted 3 times with distilled water at 100$^{\circ}C$ for 2 hrs and fractionated with cetylpyridinium chloride (CPC) and ion exchange chromatography (DEAE Separose CL-6B). The SP amounted to $23.7\%$ of the dry seaweed weight and contained $68.8\%$ carbohydrate. It was mainly constituted of rhamnose, glucose, xylose, sulfate and uronic acid and was fractionated with CPC into three (CPC-S, CPC-PS, CPC-PP) tractions. The major acid fraction CPC-PS accounted for $10.2\%$ of the dry algal weight. CPC-PS was further fractionated on DEAE Sepharose CL-6B into Fr-1 ($8.0\%$), Fr-2 ($35.8\%$), Fr-3 ($23.7\%$) fractions. The Fr-3 fraction contained $2.2\%$ protein, $21.4\%$ sulfate, $15.3\%$ uronic acid, and $72.4\%$ polysacchnrides composed of rhamnose, xylose and glucose. The Fr-2 fraction, which was richer in uronic acid ($17.5\%$) and poorer in sulfate ($19.0\%$) and total sugar ($68.8\%$) than the Fr-3, had a sugar composition close to that of Fr-3. The average molecular weights of Fr-2 and Fr-3 were 510,000 and 830,000 daltons, respectively. Fr-3 turned out to be homogeneous by cellulose acetate electrophoresis.

• Korean Chemical Engineering Research
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• v.49 no.3
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• pp.361-366
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• 2011

By using Monte Carlo simulation method we developed a new molecular simulation software which can be used to predict the thermodynamic properties of organic compounds. Starting from molecular structure and intermolecular potential function, rigorous statistical mechanical principles give a probability distribution for the behavior of a system containing many molecules, which enables us to calculate macroscopic thermodynamic properties of the system. The software developed in this work, cheMC, is based on Windows platform providing with easy access. One can efficiently administrate simulations by using an intuitive interface equipped with visualization tool and chart generation. It is expected that molecular simulations supplement the equation of state approach and will play a more important role in the study of thermodynamic properties.

• Proceedings of the Korean Journal of Food and Nutrition Conference
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• 2000.12a
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• pp.53-53
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• 2000

최근 복분자(산딸기)의 효능을 이용한 일반식품 및 기능성 식품 등의 제품 개발이 활발히 추진되고 있다. 따라서 본 연구에서는 식품차원의 연구분야 일환으로서 먼저 복분자의 일반성분, 유리당, 유리아미노산, 무기성분 및 향기성분 등을 보고한 후 앞으로 생리 활성 연구 분야에 초점을 두고 연구를 진행할 하여 학문적 자료 및 산업에 응용할시 기초자료로 활용하고자 한다. 복분자의 수분은 5.39%, 총당은 17.3%, 환원당은 8.6%, 조단백질 10.6%, 조회분은 4.5%, 조지방은1.7%, 조섬유는 3.9%이고, 유리당 함량은 sucrose 1.52%, fructose 3.98%, glucose 1.24%이고, 유기산 함량은 citric acid 10.2%, oxalic acid 6.29%로 가장 많이 함유하고 있었고, 그 다음은 malic acid 1.94%였다. 총 아미노산은 7914.1mg%이고, 필수아미노산 함량은 2622.5mg%로 나타났다. 복분자에 가장 많이 함유되어 있는 아미노산은 aspartic acid 1260.3%, 그 다음은 glutamic acid 1054.3% 순으로 함유하고 있었다. 무기성분 K가 387mg으로 가장 많이 함유되어 있었고, 복분자에서 총 52종의 성분이 화인되었는데 확인된 성분들은 관능기별로 분류하면 amylalcohol를 포함한 alcohol류 11종, valeric acid를 포함한 acid류 13종, hexanal를 포함한 carbonyl류 20종, 2-heptanone를 포함한 hydrocabon류 5종 그리고 methyl palmitate를 포함한 ester류가 3종 이었다. 관능기별로 확인된 성분들의 총 peak area%를 살펴보면 alcohol류 11.56%, acid류 38.87%, hydrocarbon류 2.89%, ester류 0.80%, 총 70.32%가 확인되었다. Alcohol류에서 linalool가 3.78%, acid류에서는 caproic acid류가 14.40%, carbonyl류에서 2-hydroxy-4-methoxyacetophenone이 2.99%, hydrocabon류에서는 aromadendrene가1.59% 그리고 ester류에서는 methyl palmitate가 0.43%으로 가장 많이 함유하고 있었다.