• Nuclear Engineering and Technology
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• 제42권5호
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• pp.562-567
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• 2010

A One-Dimensional Water Flow and Contaminant Transport in Unsaturated Zone (FTUNS) code has been developed in order to interpret radionuclide migration in an unsaturated zone. The pore-size distribution index (n) and the inverse of the air-entry value ($\alpha$) for an unsaturated zone were measured by KS M ISO 11275 method. The hydraulic parameters of the unsaturated soil are investigated by using soil from around a nuclear facility in Korea. The effect of hydraulic parameters on radionuclide migration in an unsaturated zone has been analyzed. The higher the value of the n-factor, the more the cobalt concentration was condensed. The larger the value of $\alpha$-factor, the faster the migration of cobalt was and the more aggregative the cobalt concentration was. Also, it was found that an effect on contaminant migration due to the pore-size distribution index (n) and the inverse of the air-entry value ($\alpha$) was minute. Meanwhile, migrations of cobalt and cesium are in inverse proportion to the Freundich isotherm coefficient. That is to say, the migration velocity of cobalt was about 8.35 times that of cesium. It was conclusively demonstrated that the Freundich isotherm coefficient was the most important factor for contaminant migration.

• 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.

• 대한간호학회지
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• 제47권5호
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• pp.676-688
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• 2017

Purpose: The purpose of this study was to analyze the migration patterns of new nurses and experienced nurses and to identify the factors influencing inter-regional migration for solving regional imbalances of clinical nurses in South Korea. Methods: This study involved a secondary analysis of data from the Health Insurance Review and Assessment Service (HIRA). Data were analyzed using descriptive statistics and multiple logistic regression analysis. Results: New nurses tended to migrate from Kyunggi to Seoul. However, experienced nurses tended to migrate from Seoul and Chungchung to Kyunggi. Significant predictors of inter-regional migration among new nurses were location and nurse staffing grade of hospitals. Significant predictors of inter-regional migration among experienced nurses were location, hospital type, nurse staffing grade, ownership of hospitals and age of nurses. Conclusion: Inter-regional migration occupied a small portion of total hospital movement among clinical nurses. The regional imbalances of nurses were not caused by the migration from non-metropolitan areas to Seoul. Nurse shortage problems in the small and medium hospitals of the non-metropolitan area can be solved only through improvement of work environment.

• 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.

• 한국지역지리학회지
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• 제18권1호
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• pp.101-117
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• 2012

본 연구의 목적은 전국의 귀촌자를 대상으로 설문조사를 통해 귀촌적응과정과 영농실태를 분석하여 특성에 따른 귀촌정책방안을 제언하는 것이다. 이를 위하여 도시민의 농촌지향 이주자들이 어떤 동기와 특성을 갖고 귀촌하였는지 설문조사를 통해 실태를 살펴보았다. 귀촌동기는 경제외적 사유가 주를 이루며, 귀촌 시 가장 큰 영향을 준 사람은 배우자와 부모로 나타났다. 귀촌자금은 초기영농활동을 위해 주로 사용되었으며, 영농생활 시 가장 큰 도움과 영농지식과 기술을 가장 많이 얻은 곳은 이웃 독농가였다. 영농생활의 가장 큰 애로사항과 농촌 거주시 가장 큰 불편사항은 영농자금조달과 소득수준이며 이를 위한 정부 지원책을 가장 바라고 있었다. 향후 농촌생활방향은 농업을 본업으로 하며 농촌에 계속 거주하겠다고 응답하여 미래의 농촌현실은 밝을 것이다. 앞으로 이와 같은 동향과 특성을 기초로 세밀한 도시민의 농촌지향 인구의 정착방안에 대한 발전전략 연구를 수행할 필요가 있다.

• 한국식품위생안전성학회지
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• 제12권2호
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• pp.132-140
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• 1997

Additives in plastics are capable of migrating from the packaging materials into the foodstuffs, thereby presenting a source of contamination and a potential health risk to the consumer. The migration from packaging materials into foodstuffs is first of all regulated by examining the amounts of global and specific migrated components. Besides, there is worldwide still a need for practical methods for measuring and monitoring migration from polymers, especially for the testing of migration into fatty foodstuffs. Therefore, these studies were undertaken to investigate the safety status of domestic plastic packaging materials with respect to migration. Another objective of this study was to examine the applicability of ethanol as an alternative fatty food simulant substituting for olive oil and n-heptane. The evaporation residues for various dometic plastic samples determined as described in Korean food laws were in the level from 4.3 to 14.5 mg/$\ell$, which were much lower than the limit value of 150 mg/$\ell$. The global migration values into 95 % ethanol showed to be comparable to those into n-heptane, while the olive oil migration values were comparably higher than those into ethanol or n-heptane and moreover they were not reproducible. The kinetic migration begavior of additives in polyolefin samples into 95% ethanol showed a Fickian diffusion process. The results of these studies on global migration and kinetic testings demonstrate that the ethanol could be successfully substitute for the olive oil and n-heptane as an alternative fatty food simulant, at least in contact with polyoefins.

• 펄프종이기술
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• 제48권3호
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• pp.5-13
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• 2016

This study investigated the effects of different factors on the migration of a fluorescent whitening agent (FWA) from paper treated with FWAs to non-fluorescent papers. FWA migration experiments were carried out in vertical and friction contacts between the papers dyed with FWAs and non-fluorescent papers. During the experiments, we identified the effects of the addition and types of FWAs, contact time, temperature, and relative humidity (RH) on FWA migration. The fluorescence indices of the non-fluorescent papers were measured before and after the migration experiments, and the Student's t test, a statistical tool, was utilized to compare results from different migration experiments. In vertical contact experiments, FWA migration to non-fluorescent paper was observed at $30^{\circ}C$ and 70% RH; this was attributed to the high moisture content of the paper. FWA migration did not occur significantly at $23^{\circ}C$ and 50% RH. In the friction contact experiments, FWA migrations were identified at both temperature conditions and RH percentages. The addition and types of FWAs did not increase the fluorescence index of non-fluorescent papers. Therefore, it was concluded that the moisture content of paper and the friction contact affected FWA migration from the papers containing internal and surface FWAs.

• Asian Pacific Journal of Cancer Prevention
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• 제15권6호
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• pp.2655-2661
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• 2014

Background: Talin-1 is a cytoskeleton protein that participates in cell migration and plays a role in tumor formation, migration, and metastasis in different types of cancer. Chinese investigators have observed that the levels of Talin-1 protein and mRNA expression in HCC tissues are significantly lower than in the adjacent non-cancerous tissue. However, Japanese investigators have reported that Talin-1 is upregulated in HCC. Tln2 as homologous gene of Tln-1, which encodes a very similar protein, but the role of Talin-2 is very little known in primary liver cancer (PLC). We investigated whether the expression of Talin-1 in PLC may be associated with the histological subtype as well as the role of Talin-1 in tumor cell invasion and migration using human hepatocellular carcinoma cell lines. Materials and Methods: We measured the mRNA expression levels of Talin-1 and Talin-2 in five human liver cancer cell lines and normal human liver cell ($LO_2$ cell line) by real-time PCR and the protein expression levels of Talin-1 by Western blot. Migration and invasion of the cells were assessed using transwell assays and cell scratch experiments, respectively, and proliferation was assessed by soft AGAR colony formation. Results: Talin-1 and Talin-2 expression differed significantly between the five human liver cancer cell lines and $LO_2$ cell line (p<0.05). Compared with the $LO_2$ cell line, the invasion and migration capabilities of the five cancer cell lines differed significantly (p<0.05). Similarly, the colony-forming ability differed (p<0.05). Conclusions: High levels of Talin-1 expression are correlated with reduced invasion and migration as well as decreased malignancy in human liver cancer cell lines; the suppression of Talin-1 promotes invasion and migration. In addition, Talin-2 may be correlated with invasion and migration in human hepatocellular carcinoma.

• Asian Pacific Journal of Cancer Prevention
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• 제15권10호
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• pp.4239-4243
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• 2014

Background: This study investigated the influence of curcumin on HOX transcript antisense RNA (HOTAIR)-mediated migration of cultured renal cell carcinoma (RCC) cells. Materials and Methods: Five RCC cell lines (769-P, 769-P-vector, 769-P-HOTAIR, 786-0, and Kert-3 ) were maintained in vitro. The expression of HOTAIR mRNA was determined by quantitative real-time PCR and cell migration was measured by transwell migration assay. The effects of different concentrations of curcumin (0 to $80{\mu}mol/L$) on cell proliferation was determined by the CCK-8 assay and influence of non-toxic levels (0 to $10{\mu}M$) on the migration of RCC cells was also determined. Results: Comparison of the 5 cell lines indicated a correlation between HOTAIR mRNA expression and cell migration. In particular, the migration of 769-P-HOTAIR cells was significantly higher than that of 769-P-vector cells. Curcumin at $2.5-10{\mu}M$ had no evident toxicity against RCC cells, but inhibited cell migration in a concentration-dependent manner. Conclusions: HOTAIR expression is correlated with the migration of RCC cells, and HOTAIR may be involved in the curcumin-induced inhibition of RCC metastasis.