• Journal of Microbiology and Biotechnology
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• 제18권3호
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• pp.465-471
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• 2008

Highly active, stable, and magnetically separable immobilized enzymes were developed using carboxymethyl cellulose (CMC) and diethylaminoethyl cellulose DEAE-C; hereafter designated "DEAE" as supporting materials. Iron oxide nanoparticles penetrated the micropores of the supporting materials, rendering them magnetically separable. Lipase (LP) was immobilized on the surface of the supporting materials by using cross-linked enzyme aggregation (CLEA) by glutaraldehyde. The activity of enzyme aggregates coated on DEAE was approximately 2 times higher than that of enzyme aggregates coated on CMC. This is explained by the fact that enzyme aggregates with amine residues are more efficient than those with carboxyl residues. After a 96-h enantioselective ibuprofen esterification reaction, 6% ibuprofen propyl ester was produced from the racemic mixture of ibuprofen by using DEAE-LP, and 2.8% using CMC-LP.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.294-294
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• 2010

Over the last decade, dye-sensitized solar cell (DSSC) has attracted much attention due to the high solar-to-electricity conversion efficiency up to 10% as well as low cost compared with p-n junction photovoltaic devices. DSSC is composed of mesoporous TiO2 nanoparticle electrodes coated with photo-sensitized dye, the redox electrolyte and the metal counter electrode. The performances of DSSC are dependent on constituent materials and interface as well as device structure. Replacing the heavy glass substrate with plastic materials is crucial to enlarge DSSC applications for the competition with inorganic based thin film photovoltaic devices. One of the biggest problems with plastic substrates is their low-temperature tolerance, which makes sintering of the photoelectrode films impossible. Therefore, the most important step toward the low-temperature DSSC fabrication is how to enhance interparticle connection at the temperature lower than $150^{\circ}C$. In this talk, the key issues for high efficiency plastic solar cells will be discussed, and several strategies for the improvement of interconnection of nanoparticles and bendability will also be proposed.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2018년도 춘계학술대회 논문집
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• pp.121-121
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• 2018

Copper is a promising electronic material due to low cost and high electrical conductivity. However, the oxidation problem in an ambient condition makes a crucial issue in practical applications. In here, we developed a simple and cost-effective Cu patterning method on a flexible PET film by combining a solution processable Cu nanoparticle patterning and a low temperature post-processing using acetic acid treatment, laser sintering process and acid-assisted laser sintering process. Acid-assisted laser sintering processed Cu electrode showed superior characteristics in electrical, mechanical and chemical stability over other post-processing methods. Finally, the Cu electrode was applied to the flexible electronics applications such as flexible and transparent heaters and touch screen panels.

• Journal of Magnetics
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• 제11권3호
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• pp.103-107
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• 2006

In grain oriented electrical steel process, hot band annealing has thought to be essential for obtaining good magnetic properties. New hot rolling method of heavy reduction in early hot rolling stage was applied to obtain good magnetic properties in GO process without hot band annealing. Hot rolling was carried out by varyinghot rolling reduction distribution along hot rolling pass. The heavy hot rolling reduction in rear stand improves the magnetic flux density in the case of no hot band annealing. The hot band specimens of the heavy reduction in front stand shows the elongated hot deformed microstructures in the center layer and strong {001}<110> texture.On the contrary, the heavily reduced specimens in rear stand shows the recrystallization in the center layer of hot band and strong {111}<112> and {110}<001> textures.

• 공업화학전망
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• 제22권6호
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• pp.2-12
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• 2019

최근 암 면역치료는 임상연구에서 긍정적인 결과를 보이고 있으며 암 질환의 표준치료법으로 자리 잡아가고 있다. 암 면역치료는 암의 재발과 전이를 획기적으로 개선시킬 수 있다는 이점이 있다. 하지만 전체 암 환자의 15~20%에서만 치료 효과를 보이고 심각한 부작용을 유발할 수 있다는 임상적 한계가 있다. 이러한 문제점들을 개선하기 위해서 기존에 약물전달 또는 조직공학 분야에서 활용되었던 생체재료를 도입하여 면역치료의 효과를 개선하고 부작용은 줄이려는 시도가 활발하다. 본 기고문에서는 효율적인 암 면역치료를 위한 생체재료(나노입자, 리포좀, 미립구, 및 하이드로젤)에 관한 최신 연구동향을 다루고자 한다. 고기능성 생체재료 개발과 종양 면역학 분야의 깊은 이해는 효과적인 암 면역치료제를 개발하는데 있어서 매우 중요하다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.382.2-382.2
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• 2014

We explain a method to fabricate multi-layered transparent conductive films (TCF) using graphene oxide (GO), copper powder and polyurethane (PU) solution. The flexible graphene nanosheets (GNSs) serve as nanoscale connection between conductive copper nanoparticles (CuNps) and PU nanofibers, resulting in a highly flexible TCF. To fabricate conductive films with high transmittance, polyurethane (PU) nanofibers were used for a conductive network consisting of CuNps and GNSs (CuNps-GNSs). In this experiment, copper powder and graphene oxides were mixed in deionized water with the ultrasonication for 2 h. NaBH4 solution is used as a reduction agents of CuNps and GNSs (CuNps-GNSs) under a nitrogen atmosphere in the oil bath at 100% for 24 h to mixed. The purified and dispersed CuNp-GNS were obtained in deionized water, and diluted to a 10wt.% based on the contents of GNSs. Polyurethane (PU) nanofibers on a PET substrate were formed by electrospinning method. PET slides coated with the PU nanofibers were immersed into CuNp-GNS solution for several second, rinsed briefly in deionized water, and dried to obtain self-assembled CuNp-GNS/PU films. The morphology of the multi-layered films were characterized with a field emission scanning electron microscope (FE-SEM, Hitachi S-4700) and atomic force microscope (AFM, PSIA XE-100). The electrical property was analysed by the I-V measurement system and the optical property was measured by the UV/VIS spectroscopy.

• Toxicological Research
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• 제29권3호
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• pp.181-185
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• 2013

Aluminum nanoparticles (Al-NPs) are one of the most widely used nanomaterial in cosmetics and medical materials. For this reason, Al-NP exposure is very likely to occur via inhalation in the environment and the workplace. Nevertheless, little is known about the mechanism of Al-NP neurotoxicity via inhalation exposure. In this study, we investigated the effect AL-NPs on the brain. Rats were exposed to Al-NPs by nasal instillation at 1 mg/kg body weight (low exposure group), 20 mg/kg body weight (moderate exposure group), and 40 mg/kg body weight (high exposure group), for a total of 3 times, with a 24-hr interval after each exposure. Inductively coupled plasma mass spectrometry (ICP-MS) analysis indicated that the presence of aluminum was increased in a dose-dependent manner in the olfactory bulb (OFB) and the brain. In microarray analysis, the regulation of mitogen-activated protein kinases (MAPK) activity (GO: 0043405), including Ptprc, P2rx7, Map2k4, Trib3, Trib1, and Fgd4 was significantly over-expressed in the treated mice than in the controls (p = 0.0027). Moreover, Al-NPs induced the activation of ERK1 and p38 MAPK protein expression in the brain, but did not alter the protein expression of JNK, when compared to the control. These data demonstrate that the nasal exposure of Al-NPs can permeate the brain via the olfactory bulb and modulate the gene and protein expression of MAPK and its activity.

• Environmental Engineering Research
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• 제21권1호
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• pp.99-107
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• 2016

The adsorption of inorganic mercury, Hg (II), in aqueous solution has been investigated to evaluate the effectiveness of synthesized gold (Au) nanoparticle-coated silica as sorbent in comparison with activated carbon and Au-coated sand. The synthesis of the Au-coated silica was confirmed by x-ray diffraction (Bragg reflections at $38.2^{\circ}$, $44.4^{\circ}$, $64.6^{\circ}$, and $77.5^{\circ}$) and the Au loading on silica surface was $6.91{\pm}1.14mg/g$. The synthesized Au-coated silica performed an average Hg adsorption efficiency of ~96 (${\pm}2.61$) % with KD value of 9.96 (${\pm}0.32$) L/g. The adsorption kinetics of Hg(II) on to Au-coated silica closely follows a pseudo-second order reaction where it is found out to have an initial adsorption rate of $4.73g/{\mu}g/min/$ and overall rate constant of $4.73{\times}10^{-4}g/{\mu}g/min/$. Au-coated silica particles are effective in removing Hg (II) in aqueous solutions due to their relatively high KD values, rapid adsorption rate, and high overall efficiency that can even decrease mercury levels below the recommended concentrations in drinking water.

• 멤브레인
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• 제26권5호
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• pp.351-364
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• 2016

최근 폴리아마이드 선택층에 나노물질을 혼합하여 해수담수화 성능을 높이고자 하는 연구가 활발히 이루어지고 있다. 본 총설은 역삼투 분리막 해수담수화 공정에서의 에너지 효율 향상을 위한 우수한 성능을 가진 폴리아마이드 기반 나노복합막을 소개하고자 한다. 그래핀 옥사이드 및 탄소나노튜브와 같은 탄소나노물질 및 제올라이트, 실리카 나노입자 등의 다양한 나노물질들이 기존 폴리아마이드의 투과분리성능을 높이기 위해 적용되고 있다. 본 총설에서는 최근 연구 중인 각 나노소재별 성능향상 특장점을 소개하고, 더 높은 성능을 갖는 나노복합막 제조를 위한 연구방향을 제시하고자 한다.

• Journal of Applied Biological Chemistry
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• 제59권2호
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• pp.145-147
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• 2016

Recently, conjugates of medicinal herb-derived bioflavonoids, such as quercetin, and gold nanoparticles (GNPs) have gained attention as targeted drug delivery systems. In the present study, because quercetin is an important flavonoid with anti-cancer, anti-inflammatory, and anti-oxidant properties, GNP-quercetin complexes (GNPQs) were synthesized to investigate possible adverse effects such as cytotoxicity. We found that while quercetin was cytotoxic, GNPQs were not cytotoxic towards the RAW 264.7 and THP-1 cell lines. Therefore, GNPQs may serve as a potential drug delivery system for cancer treatment.