• Korean Journal of Clinical Laboratory Science
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• v.52 no.1
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• pp.53-61
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• 2020

Cell migration is a central process for recovering from wounds triggered by physical distress besides embryogenesis and cancer metastasis. Wound healing assay is widely used as a fundamental research technique for investigation of two-dimensional cell migration in vitro. The most common approach for imitating physical wound in vitro is mechanical scratching on the surface of the confluent monolayer by using sharp materials. The iron metal pin with a suspension spring for fine adjustment of the orthogonal contact surface between the scratching point and the individual bottom of multi-well plate with planar curvatures were adopted for the creative invention of a 96-well plate wound maker. While classic tips drew diverse and zigzag scratching patterns on the confluent monolayer, our wound maker displayed synchronized linear wounds in the middle of each well of a 96-well plate that was seeded with several cell lines. Given that several types of multi-well plates commercially available are compatible with our lab-made wound maker for creating uniform scratches on the confluent monolayer for the collective cell migration in wound healing assay, it is certain that the application of this wound maker to the real-time wound healing assay in high content screening (HCS) is superior than utilization of typical polypropylene pipette tips.

• Journal of the Korean institute of surface engineering
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• v.29 no.6
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• pp.753-759
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• 1996

The artificial construction of well-defined low-dimensional (low-D) quantum structures, such as quantum wire (QWR) still attracts attention of many researchers due to their applications in room-temperature optoelectronic devices. In this work, the migration enhanced epitaxial growth (MEE) and the analysis of InAs/ AlAs QWR are reported. On the vicinal semi-insulating InP substrate of $3^o$ tilted cut from (100) surface towards (010) direction, InAs/ AlAs QWR superlattices have been successfully grown by MEE with the introduction of growth interruption at each shutter operation of MBE cell. The in-situ RHEED analyses show that MEE gives superior step-flow growth (SFG) and sharper interface formation over a conventional MBE growth. We have grown 4 samples in series varying the growth temperature. The QWR samples are analyzed by photoluminescence (PL) and atomic force microscopy (AFM). From the AFM images, we can get the definitely resolved 1-D structures. This structure is believed to be due to the MEE method and its separation is better than any other data from others. We are now studying the dependence of the structure on the growth temperature.

• Food Science of Animal Resources
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• v.23 no.2
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• pp.103-108
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• 2003

The effect of fat content, thickness, and storage temperature and period of fresh meat samples on the migration of di-(2-ethylhexyl) adipate(DEHA) from plasticized PVC film was investigated. Pork samples were prepared to have different fat contents by mixing with pork loin and pork backfat and stored at 5$^{\circ}C$ for 2 d. The migration values of DEHA into the pork samples were increased with a high fat content. There was a gradual increase in the DEHA concentration as a function of prolonged exposure period and elevated storage temperature when the pork samples were stored at -2, 5 and l0$^{\circ}C$ for up to 7 d, respectively. The migration of DEHA into fresh pork and beef was limited only to a small depth under the meat surface($\leq$2 cm). The migration value was higher when the pork belly was wrapped double with plasticized PVC film compared to once after storage at 5$^{\circ}C$ for 3 d. However, when the samples was minced and repacked with new film after 2 d, and kept for a further 1 d, these showed lower migration value compared to the above two intact samples. Migration values exceeded in most cases the upper limit for DEHA migration proposed by the EU(18 mg/kg or 3 mg/d㎡), even though no limitation is currently set in Korea.

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.3
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• pp.287-292
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• 2017

Vitiligo is an intriguing depigmentary disorder and is notoriously difficult to be treated. The ultimate goal of vitiligo treatment is to replenish the lost melanocytes by immigration from hair follicle and to restore the normal function of melanogenesis by residual melanocytes. There are two types of topical calcineurin inhibitors called tacrolimus and pimecrolimus, and are recommended as the first-line treatments in vitiligo. Although pimecrolimus is efficacious for the repigmentation of vitiligo, its intrinsic mechanisms have never been investigated in vitro. This research aimed to study the ability of pimecrolimus on stimulating melanogenesis, melanocyte migration and MITF (microphthalmia associated transcription factor) protein expression. Results showed that pimecrolimus at the dosages of 1, 10, $10^2$nM were neither mitogenic nor cytotoxic to melanocytes. The addition of pimecrolimus at 10, $10^2$ and $10^3nM$ significantly increased intracellular tyrosinase activity, which was consistent with the elevated content of melanin content at the same concentrations. The peak effect was seen at 72 h in response to $10^2$nM pimecrolimus. Results of the wound scratch assay and Transwell assays indicate that pimecrolimus is effective in facilitating melanocyte migration on a collagen IV-coated surface. In addition, MITF protein yield reached the highest by pimecrolimus at $10^2nM$. In brief, pimecrolimus enhances melanin synthesis as well as promotes migration of melanocytes directly, possibly via their effects on MITF protein expression.

• Korean Journal of Materials Research
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• v.20 no.1
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• pp.19-24
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• 2010

The current study examined Ag migration from the Ag paste bump in the SABiT technology-applied PCB. A series of experiments were performed to measure the existence/non-existence of Ag in the insulating prepreg region. The average grain size of Ag paste was 30 nm according to X-ray diffraction (XRD) measurement. Conventional XRD showed limitations in finding a small amount of Ag in the prepreg region. The surface morphology and cross section view in the Cu line-Ag paste bump-Cu line structure were observed using a field emission scanning electron microscope (FE-SEM). The amount of Ag as a function of distance from the edge of Ag paste bump was obtained by FE-SEM with energy dispersive spectroscopy (EDS). We used an electron probe micro analyzer (EPMA) to improve the detecting resolution of Ag content and achieved the Ag distribution function as a function of the distance from the edge of the Ag paste bump. The same method with EPMA was applied for Cu filled via instead of Ag paste bump. We compared the distribution function of Ag and Cu, obtained from EPMA, and concluded that there was no considerable Ag migration effect for the SABiT technology-applied printed circuit board (PCB).

• Parasites, Hosts and Diseases
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• v.42 no.4
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• pp.151-157
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• 2004

Developmental surface ultrastructure of Macroorchis spinulosus was studied by scanning electron microscopy. One-day-old juvenile fluke was leaf-shaped and bent ventrally. Body surface was covered densely with peg-like spines and with cobblestone-like cytoplasmic processes. Ciliated sensory papillae were concentrated around oral sucker. Several unciliated sensory papillae occurred equidistantly on oral sucker and acetabulum. The ciliated papillae appeared in two longitudinal lines symmetric bilaterally on dorsal surface. On adult flukes, tegumantal spines became wider in middle of the body surface. The cytoplasmic processes differentiated into more fine velvety form. It is likely that the differentiated fine cytoplasmic processes are an increased absorptive surface to adult M. spinulosus. It is suggested that single pointed tegumental spines on anterior half of the body may be supportive for this fluke to migration.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.45.2-46
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• 2020

Various processes, such as space weathering and granular convection, are occurring on asteroids' surfaces. Estimation of the surface exposure timescale is essential for understanding these processes. The Hayabusa mission target asteroid, (25143) Itokawa (Sq-type) is the only asteroid whose age is estimated from remote sensing observations as well as sample analyses in laboratories. There is, however, an unignorable discrepancy between the timescale derived from these different techniques. The ages estimated based on the solar flare track density and the weathered rim thickness of regolith samples range between 102 and 104 years [1][2]. On the contrary, the ages estimated from the crater size distributions and the spectra cover from 106 to 107 years [3][4]. It is important to notice that there is a common drawback of both age estimation methods. Since the evidence of regolith migration is found on the surface of Itokawa [5], the surficial particles would be rejuvenated by granular convection. At the same time, it is expected that the erasure of craters by regolith migration would affect the crater size distribution. We propose a new technique to estimate surface exposure age, focusing on the bright mottles on the large boulders. Our technique is less prone to the granular convection. These mottles are expected to be formed by impacts of mm to cm-sized interplanetary particles. Together with the well-known flux model of interplanetary dust particles (e.g., Grün, 1985 [6]), we have investigated the timescale to form such mottles before they become dark materials again by the space weathering. In this work, we used three AMICA (Asteroid Multi-band Imaging Camera) v-band images. These images were taken on 2005 November 12 during the close approach to the asteroid. As a result, we found the surface exposure timescales of these boulders are an order of 106 years. In this meeting, we will introduce our data analysis technique and evaluate the consistency among previous research for a better understanding of the evolution of this near-Earth asteroid.

• Food Science and Preservation
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• v.18 no.5
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• pp.721-728
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• 2011

1(3)-palmitoyl-2-oleoyl-3(1)-stearoyl-(POS)-glycerol-enriched reaction products were synthesized from camellia oil, palmitic ethyl ester, and stearic ethyl ester via lipase-catalyzed interesterification. Response surface methodology (RSM) was employed to optimize the production of the POS-enriched reaction product (Y1, %) and the stearicand palmitic-acid contents at the sn-2 position due to acyl migration (Y2, %). The reaction factors were the enzyme amount (X1, 2-6%), reaction time (X2, 60-360 min), and substrate molar ratio of camellia oil to palmitic ethyl ester and stearic ethyl ester (X3, 1-3 mol). The predictive models for Y1 and Y2 were adequate and reproducible as no lack of fit was signified (0.128 and 0.237) and as there were satisfactory levels of R2 (0.968 and 0.990, respectively). The optimal conditions for the reaction product for maximizing Y1 while minimizing Y2 were predicted at the reaction combination of 5.86% enzyme amount, 60 min reaction time, and 1:3 substrate molar ratio (3 moles of palmitic ethyl ester and 3 moles of stearic ethyl ester). Actual reaction was performed under the same conditions as above, and the resulting product contained 20.19% TAG-P/O/S and 12.71% saturated fatty acids at the sn-2 position.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.75-76
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• 2014

Copper는 2차 전지 및 PCB 등 Electrical Device에 빠짐없이 들어가는 핵심 부품이다. 반도체 배선재료 또한 Aluminum에서 Copper로 대체되어 Electrical Conductivity 및 Electro-migration 문제를 해결할 수 있었다. 최근 배선의 미세화 및 전지용량 증가로 인해 보다 얇으면서, 동시에 높은 기계적 강도를 가지는 Copper Film의 필요성이 요구되고 있다.

• Journal of the Korean institute of surface engineering
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• v.22 no.3
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• pp.145-153
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• 1989

양극산화 피막의 형성 반응에 대한 연구는 1930년대부터 되어 왔으며, 특히 High Field Conduction에 대한 물리학자들의 관심도는 아주 높아었다. 1960년대 이르러 비정질 구조에 대한 심도 있는 연구가 진행되면서, 여러 가지 이론적으로 풀지 못하는 실험실적 결과들에 대한 제한들이 나오게 되었고, Ionic Migration Process에 대한 Kinetics는 많은 발전을 보게 되었다. 최근까지의 연구결과, Ioinc Conduction Mechanism은 Anodic Film의 미세 결정 구조와 밀접한 연관성을 가진다는 결론에 도달하였고, 비정질 구조의 High Field하에서의 거동에 대한 새로운 분야의 연구가 진행되고 있다. 본 고에서는 반응 Mechanism에 관한 연구결과들을 1930년대 이후 어떻게 진행되어 설명 되었는가를 조명하므로서 실제 실험 결과의 해석게 도움이 되었으면 하는 바램이다.