• Bulletin of the Korean Chemical Society
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• 제9권4호
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• pp.218-223
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• 1988

The surface-enhanced Raman scattering of L-phenylalanyl-glycine (L-Phe-Gly), L-phenylalanyl-glycyl-glycine (L-Phe-Gly-Gly), glycyl-glycyl-L-phenylalanine (Gly-Gly-L-Phe), L-tyrosyl-glycine (L-Tyr-Gly), and L-tyrosyl-glycyl-glycine (L-Tyr-Gly-Gly) adsorbed on silver colloidal particles have been investigated. More detailed investigations on the surface-enhanced Raman scattering from L-phenylalanine (L-Phe), glycyl-L-phenylalanine (Gly-L-Phe), L-tyrosine (L-Tyr), and glycyl-L-tyrosine (Gly-L-Tyr) than in ref. 17 have also been made. It has been found that the above molecules adsorb on the surface via both the carboxylate ($COO^-$) and amino ($NH_2$) groups.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2001년도 가을 학술발표회 논문집
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• pp.386-389
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• 2001

Researches for nanotechnology are inherently multidisciplinary since on the biological, and chemical components and systems are essentially the same. As the synthetics develop, many people are concerned about the influences of natural environment and hygiene of manufactures. By this reason, a new area has developed in the realism of textile finishing. The aim of this work is to consolidate nanotechnology into bacteriostasis of textile. (omitted)

• Bulletin of the Korean Chemical Society
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• 제24권5호
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• pp.633-637
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• 2003

We have studied the surface-enhanced Raman spectroscopy (SERS) spectrum of quinomethionate (6-methyl-1,3-dithiolo[4,5-b]quinoxalin-2-one), which is an insecticide or fungicide used on vegetables and wheat. We observed no signals in the ordinary Raman spectra of solid-state quinomethionate, but when it was adsorbed on a colloidal silver surface, strong vibrational signals were obtained at a very low concentration. The SERS spectra were obtained by silver colloids prepared by the Creighton et al. method. The influence of pH and the aggregation inductors ($Cl^-,\;Br^-,\;I^-,\;F^-$) on the adsorption mechanism was investigated. Two different adsorption mechanisms were deduced, depending on the experimental conditions: The one N atom or two N atoms are chemisorbed on an Ag surface. An important contribution of the chemical mechanism was inferred when the one N atom was perpendicularly adsorbed on a surface. It is possible that quinomethionate can be detected to about $10^{-5}$ M.

• Bulletin of the Korean Chemical Society
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• 제33권4호
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• pp.1135-1140
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• 2012

An electrochromatographic microchip with carboxyl-group-derivatized mono-disperse silica packing was prepared from the corresponding colloidal silica solution by utilizing capillary action and self-assembly behavior. The silica beads in water were primed by the capillary action toward the ends of cross-patterned microchannel on a cyclic olefinic copolymer (COC) substrate. Slow evaporation of water at the front of packing promoted the self-assembled packing of the beads. After thermally binding a cover plate on the chip substrate, reservoirs for sample solutions were fabricated at the ends of the microchannel. The packing at the entrances of the microchannel was silver coated to fix utilizing an electroless silver-plating technique to prevent the erosion of the packed structure caused by the sudden switching of a high voltage DC power source. The electrochromatographic behavior of the microchip was explored and compared to that of the microchip with bare silica packing in basic borate buffer. Electrophoretic migration of Rhodamine B was dominant in the microchip with the carboxyl-derivatized silica packing that resulted in a migration approximated twice as fast, while the reversible adsorption was dominant in the bare silica-packed microchip. Not only the faster migration rates of the negatively charged FITC-derivatives of amino acids but also the different migration due to the charge interaction at the packing surface were observed. The electrochromatographic characteristics were studied in detail and compared with those of the bare silica packed microchip in terms of the packing material, the separation potential, pH of the running buffer, and also the separation channel length.

• Bulletin of the Korean Chemical Society
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• 제32권2호
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• pp.613-619
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• 2011

Colloidal silver nanoparticles (AgNPs) have been commercialized as the typically stabilized form via the addition of a variety of surfactants or polymers. Herein, to examine the effects of stabilizing AgNPs in suspension, we modified the surface of bare AgNPs with four type of surfactants (NaDDBS, SDS, TW80, CTAB) and polymers (PVP, PAA, PAH, CMC). The modified AgNPs was applied to compare suspension stability and nanotoxicity test using Escherichia coli (E. coli) as a model organism. Modification of AgNPs surface using chemical stabilizer may be not related with molecular weight, but chemical structure such as ionic state and functional group of stabilizer. In this study, it is noteworthy that AgNPs modified with a cationic stabilizer (CTAB, PAH) were importantly toxic to E. coli, rather than anionic stabilizers (NaDDBS, SDS). Comparing similar anionic stabilizer, i.e., NaDDBS and SDS, the result showed that lipophilicity of chemical structure can affect on E. coli, because NaDDBS, which contains a lipophilic benzene ring, accelerated the cytotoxicity of AgNPs. Interestingly, none of the stabilizers tested, including biocompatible nonionic stabilizers (i.e., TW80 and cellulose) caused a reduction in AgNP toxicity. This showed that toxicity of AgNPs cannot be reduced using stabilizers.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.53-53
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• 2010

The development of synthetic pathway to produce a highly yield nanoparticles is an important aspect of industrial technology. Herein, we report a simple, rapid approach to synthesize organic-soluble Cu and Ag nanoparticles in colloidal method for the application in a conductive pattern using inkjet printing. The silver nanoparticles have been synthesized in highly concentrated organic phase. The Cu nanoparticles have been synthesized by the reducing of the copper oxide materials using acid molecules in high concentrated organic phase. Their sintering and electric conductivity properties were investigated by melting process between $200^{\circ}C$ and $250^{\circ}C$ for application to printed electronics.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.155.2-155.2
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• 2014

Plasma Enhanced Atomic Layer Deposition(PEALD)와 Atomic Layer Deposition(ALD) Techniques는 '정확한 두께 조절' 및 '우수한 균일도'를 가지는 신뢰할 수 있는 진공 기술이다. 본 연구에서는 다공성 구조를 가지는 기판을 대상으로 PEALD와 ALD Techniques을 이용한 $Al_2O_3$ 형성 공정의 증착 특성을 비교하였다. 각 공정은 공통적으로 Tris-Methyl-Aluminium(TMA)을 첫번째 전구체로 사용하였고 purge gas로는 Nitrogen를 사용하였다. 그리고 두번째 전구체로 PEALD 공정에서는 Oxygen Plasma를 사용하였고 ALD 공정에서는 Water를 사용하였다. 복잡한 다공성 구조를 가지는 기판은 $TiO_2$ Nano-Particle paste과 colloidal Silver paste를 소결시켜 제작하여 사용하였다. 각 공정의 차이점을 비교하기 위해서 배기단에 Capacitor Diaphram Gauge(CDG)와 Residual Gas Analyzer(RGA)를 통해서 압력과 잔류 가스를 모니터하였다. 그리고 각 공정을 통해서 porous한 Nano-Particles Network에 형성된 $Al_2O_3$막의 특성을 비교하기 위해서 FE-SEM과 EDX를 통해서 관찰하였다. 또한 좀 더 자세한 비교 분석을 위해서 $Al_2O_3$ 막이 형성된 porous한 Nano-Particles Networks의 각 각의 particles들을 분산시켜 TEM과 AFM를 통해서 관찰하였다. 나아가 전기적 물성의 차이점을 비교하기 위해서 IV 및 CV를 측정하였다. 위의 일련의 비교 실험을 통해서 'PEALD과 ALD을 이용한 다공성 기판의 증착 특성'에 대하여 고찰하였다.

• Tribology and Lubricants
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• 제11권5호
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• pp.40-46
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• 1995

This study concerns the design and development of the non-vibrating capacitance probe which could be used as a non-contact sensor for tribological wear. This device detects surface charge through temporal variation in the work function of a material. Experiments are performed to demonstrate the operation of the probe on a roating aluminum shaft. The reference electrode of the probe, made of lead, is placed adjacent (< 1.25-mm distance) to the shaft. Both surfaces which are electrically connected, form a capacitor. An artificial spatial variation in the work function is imposed on the shaft surface by coating a segment along the shaft circumference with a colloidal silver paint. As the shaft rotates, the reference electode senses changing contact potential difference with the shaft surface, owing to compositional variation. Temporal variation in the contact potential difference induces a current through the electrical connection. This current is amplified and converted to a voltage signal by an electoronic circuit with an operational amplifier. The magnitude of the signal decreases asymptotically with the electrode-shaft distance and increases linearly with the rotational frequency. These results are consistent with the theoretical model. Potential applications of the probe on wear monitoring are proposed.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제3권1호
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• pp.23-29
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• 2000

목 적: 소아의 만성 반복성 복통에서 H. pylori의 역할에 대해서는, 논란이 있지만 중요한 원인 중의 하나일 것으로 생각되고 있다. 성인과는 달리 소아에서는 궤양성 질환이 없는 경우에도 제균 치료를 하는 것이 상례이다. H. pylori 제균 치료는 제균효과와 안전성 그리고 환자의 순응도와 경제성 등의 기준에 따라 선택하여 사용하고 있다. 편이성과 경제성이 좋은 2제 요법으로는 omeprazole과 clarithromycin 병용 투여의 효과가 인정받고 있으며, omeprazole과 amoxicillin 병용 투여에 대해서는 보고에 따라 제균 효과가 35~85%로 일정하지 않았다. 이에 저자들은 만성 반복성 복통 환아에서 H. pylori 감염증에 대한 omeprazole 및 amoxicillin 2주 치료의 효과를 알아보고자 본 연구를 시행하였다. 방 법: 1998년 4월부터 1999년 4월까지 연세의대 세브란스병원 소아과에 만성 반복성 복통으로 내원하여 위십이지장 내시경을 시행받은 환아 중 생검 조직의 CLO 검사 또는 은염색에서 H. pylori 감염증으로 진단받은 57례에서 omeprazole (0.7 mg/kg/day)과 amoxicillin (50 mg/kg/day)을 2주간 투여하였으며, 이들 중 추적 검사가 가능하였던 24례에 대해 H. pylori 제균 효과를 알아보았다. H. pylori 제균은 투약 종료 4주 이후에 위십이지장 내시경을 시행하여 얻은 생검 조직의 CLO 검사와 은염색에서 모두 음성인 경우로 정의하였다. 결 과: 대상 환아는 남아 15례(63%), 여아 9례(37%)였고 7세 미만이 4례(17%), 7세에서 12세 사이가 14례(58%), 12세 이상이 6례(25%)였다. 내시경 진단은 결절성 위염이 11례(46%), 표재성 위염7례(29%), 소화성 궤양 4례(17%), 정상이 2례(8%)였다. Omeprazole 및 amoxicillin 2제 2주 투약 종료 4주 후 시행한 내시경 검사상 12례에서 H. pylori가 제균되어 제균율은 50%이었으며, 나머지 12례에서는 제균이 되지 않았다. 제균이 되지 않았던 12례의 환아들 중 8례는 추적 관찰이 되지 않았고, 나머지 4례에서는 omeprazole, amoxicillin, clarithromycin, colloidal bismuth subcitrate ($Denol^{(R)}$), metronidazole 중 2~3가지 약제를 조합하여 2~3주 병용요법을 시행한 결과 모두 제균이 되었다. 결 론: 만성 반복성 복통 환아에서 H. pylori 감염증에 대한 PPI (omeprazole) 및 amoxicillin 2제의 2주 치료요법의 제균율은 50%로 기존의 다른 보고들에서와 유사하였다. 그러나, H. pylori 제균요법의 선택에 있어서 가장 중요한 것은 H. pylori 제균율이므로, 만성 반복성 복통 환아에서 H. pylori 감염증에 대한 PPI (omeprazole) 및 amoxicillin 2제의 2주 요법은 일차 치료로서는 효과적이지 않은 것으로 생각된다.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2002년도 제38회 학술심포지움
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• pp.20-47
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• 2002

Two-dimensional gel electrophoresis (2-DE) maps for human stomach tissue proteins have been prepared by displaying the protein components of the tissue by 2-DE and identifying them using mass spectrometry. This will enable us to present an overview of the proteins expressed In human stomach tissues and lays the basis for subsequent comparative proteome analysis studies with gastric diseases such as gastric cancer. In this study, 2-DE maps of soluble fraction proteins were prepared on two gel images with partially overlapping pH ranges of 4-7 and 6-9. On the gels covering pH 4-7 and pH 6-9, about 900 and 600 protein spots were detected on silver staining, respectively. For protein identification, proteins spots on micropreparative gels stained by colloidal Coomassie Brilliant Blue G-250 were excised, digested in-gel with trypsln, and analyzed by peptide mass fingerprinting with delayed extraction-matrix assisted laser dosorption/ionization-mass spectrometry (DE-MALDI-MS). In all, 243 protein spots (168 spots in acidic map and 75 spots in basic map) corresponding to 136 different proteins were identified. Besides these principal maps, maps of lower resolution, i.e. overview maps (displayed on pH 3-10 gels) for total homogenate and soluble fraction, are also presented with some identifications mapped on them. Based on the 2-DE maps presented in this study, a 2-DE database for human stomach tissue proteome has been constructed and available at http://proteome.gsnu.ac.kr/DB/2DPAGE/Stomach/. The 2-DE maps and the database resulting from this study will serve important resources for subsequent proteomic studies for analyzing the normal protein variability in healthy tissues and specific protein variations in diseased tissues.