• Journal of Welding and Joining
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• 제29권5호
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• pp.95-98
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• 2011

Recently, there is a growing tendency that fine-pitch electronic devices are increased due to higher density and very large scale integration. Finer pitch printed circuit board(PCB) is to be decrease insulation resistance between circuit patterns and electrical components, which will induce to electrical short in electronic circuit by electrochemical migration when it exposes to long term in high temperature and high humidity. In this research, the effect of soldering flux acting as an electrical carrier between conductors on electrochemical migration was investigated. The PCB pad was coated with OSP finish. Sn3.0Ag0.5Cu solder paste was printed on the PCB circuit and then the coupon was treated by reflow process. Thereby, specimen for ion migration test was fabricated. Electrochemical migration test was conducted under the condition of DC 48 V, $85^{\circ}C$, and 85 % relative humidity. Their life time could be increased about 22% by means of removal of flux. The fundamentals and mechanism of electrochemical migration was discussed depending on the existence of flux residues after reflow process.

• 한국재료학회지
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• 제15권1호
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• pp.54-60
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• 2005

Recently a lots of problems have observed in high densified and high integrated electronic components. One of them is ion migration phenomena, which induce the electrical short of electrical circuit. ion migration phenomena has been observed in the field of exposing the specific environment and using for a long tin e. This study was evaluated the generation time of ion migration and was investigated properly test method through water drop test and high temperature high humidity test. Also we observed direct causes and confirmed generation mechanism of dendritic growth as we reproduced the ion migration phenomena. We utilized PCB(printed circuit board) having a comb pattern as follows 0.5, 1.0, 2.0 mm pattern distance. Cu, SnPb and Au were electroplated on the comb pattern. 6.5 V and 15 V were applied in the comb pattern and then we measured the electrical short time causing by ion migration. In these results, we examined a difference of ion migration time depending on pattern materials, applied voltage and pattern spacing of PCB conductor.

• BMB Reports
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• 제53권12호
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• pp.646-651
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• 2020

Bone resorption is linked to bone formation via temporal and spatial coupling within the remodeling cycle. Several lines of evidence point to the critical role of coupling factors derived from pre-osteoclasts (POCs) during the regulation of bone marrow-derived mesenchymal stem cells (BMMSCs). However, the role of glial cell-derived neurotrophic factor (GDNF) in BMMSCs is not completely understood. Herein, we demonstrate the role of POC-derived GDNF in regulating the migration and osteogenic differentiation of BMMSCs. RNA sequencing revealed GDNF upregulation in POCs compared with monocytes/macrophages. Specifically, BMMSC migration was inhibited by a neutralizing antibody against GDNF in pre-osteoclast-conditioned medium (POC-CM), whereas treatment with a recombinant GDNF enhanced migration and osteogenic differentiation. In addition, POC-CM derived from GDNF knock-downed bone marrow macrophages suppressed BMMSC migration and osteogenic differentiation. SPP86, a small molecule inhibitor, inhibits BMMSC migration and osteogenic differentiation by targeting the receptor tyrosine kinase RET, which is recruited by GDNF into the GFRα1 complex. Overall, this study highlights the role of POC-derived GDNF in BMMSC migration and osteogenic differentiation, suggesting that GDNF regulates bone metabolism.

• BMB Reports
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• 제57권5호
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• pp.250-255
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• 2024

Due to their stem-like characteristics and immunosuppressive properties, Mesenchymal stem cells (MSCs) offer remarkable potential in regenerative medicine. Much effort has been devoted to enhancing the efficacy of MSC therapy by enhancing MSC migration. In this study, we identified deubiquitinase BRCA1-associated protein 1 (BAP1) as an inhibitor of MSC migration. Using deubiquitinase siRNA library screening based on an in vitro wound healing assay, we found that silencing BAP1 significantly augmented MSC migration. Conversely, BAP1 overexpression reduced the migration and invasion capabilities of MSCs. BAP1 depletion in MSCs upregulates ERK phosphorylation, thereby increasing the expression of the migration factor, osteopontin. Further examination revealed that BAP1 interacts with phosphorylated ERK1/2, deubiquitinating their ubiquitins, and thus attenuating the ERK signaling pathway. Overall, our study highlights the critical role of BAP1 in regulating MSC migration through its deubiquitinase activity, and suggests a novel approach to improve the therapeutic potential of MSCs in regenerative medicine.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.493-496
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• 2007

Korean Institute of Geosciences and Mineral Resources (KIGAM) has studied on gas hydrate in the Ulleung Basin, East sea of Korea since 1997. Most of all, a evidence for existence of gas hydrate, possible new energy resources, in seismic reflection data is bottom simulating reflection (BSR) which parallel to the sea bottom. Here we conducted the conventional data processing for gas hydrate data and Kirchhoff prestack depth migration. Kirchhoff migration is widely used for pre- and post-stack migration might be helpful to better image as well as to get the geological information. The processed stack image by GEOBIT showed some geological structures such as faults and shallow gas hydrate seeping area indicated by strong BSR. The BSR in the stack image showed at TWT 3.07s between shot gather No 3940 to No 4120. The estimated gas seeping area occurred at the shot point No 4187 to No 4203 and it seems to have some minor faults at shot point No 3735, 3791, 3947 and 4120. According to the result of depth migration, the BSR showed as 2.3km below the sea bottom.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.526-526
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• 2013

Plasma technology isbeing developed for a range of medical applications including wound healing. However, the effect of plasma on many cells and tissues is unclear. Cell migration and cell proliferation are very important biological processes which are affected by plasma exposure and might be a potential target for plasma therapy during wound healing treatment. In this study, we confirmed the plasma exposure time and incubation time after plasma treatment in skin fibroblast (L-929 cells) to evaluate the optimal conditions forplasma exposure to the cell in-vitro. In addition, we used a scratch method to generate artificial wound for evaluating the cell migration by plasma treatment. Where, the cells were treated with plasma and migration rate was observed by live-cell imaging device. To find the cell proliferation, cell viability assay was executed. The results of this study indicate the increased cell proliferation and migration on mild plasma treatment. The mechanisms for cell migration and cell proliferation after plasma treatment for future studies will be discussed.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2003년도 Annual Meeting of KSAP : International Symposium on Pharmaceutical and Biomedical Sciences on Obesity
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• pp.76-76
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• 2003

Mast cells accumulation can be causally related with several allergic inflammations. Previous work has demonstrated that glucocorticoids decreased tissue mast cell number and stem cell factor (SCF)-induced migration of mast cells required p38 mitogen-activated protein kinase (MAPK) activation. In the present study, we investigated the effects of dexamethasone on SCF-induced migration of rat peritoneal mast cells (RPMCs). SCF significantly induced migration of RPMCs at 4 h. Dexamethasone dose-dependently inhibited SCF-induced migration of RPMCs (about 90.1% at 100 nM, P<0.05). MAPK p38 inhibitor, SB203580 (20 ${\mu}$M) also inhibited the SCF-induced migration. The ability of SCF to enhance morphological alteration and F -actin formation was also abolished by treatment of dexamethasone. Dexamethasone inhibited SCF-induced p38 MAPK activation to near basal level and induced the MKP-1 expression. In addition, SCF-induced inflammatory cytokine production was significantly inhibited by treatment of dexamethasone or SB203580 (p<0.01). Our results show that dexamethasone potently regulates SCF -induced migration, p38 MAPK activation and inflammatory cytokine production through expression of MKP-l protein in RPMCs. Such modulation may have functional consequences during dexamethasone treatment, especially mast cell-mediated allergic inflammation disorders.

• 농촌계획
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• 제24권3호
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• pp.127-135
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• 2018

In countries and regions population plays an important role. Recently the importance of population migration increased as population growth slowed. Researches on population migration are mainly focused on the analysis of the population movement factors and the regional structure analysis using the network analysis method. Analysis of regional structure through population movement is not enough to explain the phenomenon of migration of small cities and rural regions. In this study, to overcome the limit of previous studies the characteristics of the population movement rate according to the size of the population were analyzed. Also network analysis using the population movement OD (Origin and Destination) and population movement rate OD were conducted and the results of them were compared. As the results of analysis by the regional population scale, the population movement by population size showed a big difference in the areas with more than 100 thousand people and less than 100 thousand people. Migration to the outside of the province was the most frequent in regions with 30,000~50,000 people. The population migration rate network analysis result showed that the new area with large population inflow capacity was identified, which could not be found in the population movement network analysis because population movement number is small. The population movement rate irate is expected to be used to identify the central regions of the province and to analyze the difference in resident attractiveness.

• 한국시스템다이내믹스연구
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• 제11권4호
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• pp.117-142
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• 2010

National territorial policies require a series of dynamic simulations, which would facilitate effectiveness measuring and forecasting works geared towards territorial policies under consideration or implementation. This paper aims at designing an integrated prototype for the proposed territorial policies. After the simulation exercises for the Ochang Industrial Complex(OIC) in Chungbuk Province, this study firstly finds meaningful mismatch phenomena between housing and population increases as the in-migration time lag seems inevitable even after the housing construction is in a mature state. Secondly, the OIC development exerts more significant impact on the number of employees than that of business units. Thirdly, in- and out-migration orders are different during the first and second stages of OIC development. That is, Chungbuk Province records the largest in terms of in-migration volume, followed by the Capital and Non-Capital Regions. Even though Chungbuk Province ranks the top position in the out-migration volume, the rank of the Capital and Non-Capital Regions is reversed: the our-migration volume towards the Non-Capital Region outruns that of the Capital Region.

• 농촌계획
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• 제11권3호
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• pp.59-67
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• 2005

According to diverse studies in population migration, there has been a strong age-dependent population distribution in Korea. It is shown that a particular age-group tends to reside in a particular locale or community and the effect possesses usually statistical significance. We quantitatively address this issue: how certain division of age group resides in different region of the country, and investigate possible cause of this migration pattern for different age groups. In this study, population migration trend at age groups of 20s, 30s, 40s and 50s has been analyzed incorporating a spatial econometrics model that accounts for diverse statistical pitfalls such as spatial autocorrelation and spatial dependency. We found that migration trend for different age group corresponds to regional characteristics differently. The study concludes with some policy implications and suggests a need of further study.