• Korean Journal of Materials Research
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• v.8 no.4
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• pp.368-374
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• 1998

The corrosion characteristics of zirconium alloys have been investigated in various aqueous solutions of LiOH. NaOH, KOH, RbOH. and CsOH at 3S$0^{\circ}C$. The concentrations of solutions were set to 4.3 mmol and 32.Smmol with equimolar $M^+$ and OH . The oxide characterization was performed using TEM on the samples corroded in 32. Smmol LiOH, NaOH, and KOH solution. The samples were prepared to have the same oxide thickness for the pretransition and post- transition regimes. Considering the trend of experimental data, the cation would playa major role in the corrosion process of Zr alloys in alkali hydroxide solutions. The microstructures of the oxides formed in various solutions were quite different. In LiOH solution the oxides grown in pre-transition as well as post-transition had the equiaxed structures with many pores and open grain boundaries. The oxides grown in NaOH solution had the protective columnar structures in pre-transition and the equiaxed structures with many open grain boundaries in post- transition. On the other hand. in KOH solution the columnar structure was maintained from pre- transition to post- transition. It was considered that the cation incorporation into zirconium oxide controlled the oxide characteristics and the corrosion acceleration in alkali hydroxide solutions.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.9
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• pp.4435-4439
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• 2012

Purpose: This study aimed to explore the role of the Twist gene in the epithelial-mesenchymal transition of ovarian cancer. Methods: An RNA interference plasmid expressing a small interfering RNA (siRNA)-targeting Twist (Twist siRNA vector) was designed, constructed, and transfected into the human ovarian cancer cell line A2780. Transfection efficiency was assessed under a fluorescence microscope. Changes in the expression of Twist mRNA in A2780 after transfection with the pGenesil Twist shRNA plasmid were analyzed through RT-PCR. MTT assays and adhesion experiments were applied to determine changes in proliferation and adhesion ability of A2870 after transfection with the Twist shRNA plasmid. Changes in the expression of the E-cadherin and N-cadherin proteins in A2780 after transfection with the Twist shRNA plasmid were analyzed using Western blotting. Result: The restructuring plasmid pGenesil-Twist shRNA was constructed successfully. After 48 h of culture, 80% of the cells expressed high-intensity GFP fluorescence and stability. The expression of Twist decreased significantly after the transfection of the Twist shRNA plasmid (P<0.05). Proliferation of the transfected Twist shRNA cells showed no difference with that of the A2780-nontransfection or A2780-si-control groups (P>0.05) but the adhesion ability of A2780 decreased dramatically (P<0.05). Expression of the E-cadherin protein increased, whereas that of the N-cadherin protein decreased compared with that in the A2780-nontransfection or A2780-si-control groups (P<0.05). Conclusion: Twist is essential for epithelial-mesenchymal transition, invasion, and metastasis of ovarian cancer.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.854-861
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• 2005

The functional behavior of a portable consumer electronic (PCE) product is nearly all expressed with human-machine interaction (HMI) tasks. Although physical prototyping and computer aided design (CAD) software can show the appearance of the product, they cannot properly reflect its functional behavior. In this paper, we propose a virtual prototyping (VP) system that incorporates virtual reality and HMI functional simulation in order to enables users to capture not only the realistic look of a PCE product but also its functional behavior. We obtain geometric part models of the product and their assembly and kinematics information with the help of CAD and reverse engineering tools, and visualize them with various display tools. We adopt state transition methodology to capture the HMI functional behavior of the product into a state transition chart, which is later used to construct a finite state machine (FSM) for the functional simulation of the product. The FSM plays an important role to control the transition between states of the product. The proposed VP system receives input events such as mouse clicks on buttons and switches of the virtual prototype model, and it reacts to the events based on the FSM by activating associated activities. The VP system provides the realistic visualization of the product and the vivid simulation of its functional behavior. It can easily allow users to perform functional evaluation and usability testing. Moreover, it can greatly reduce communication errors occurring in a typical product development process. A case study about VP of an MP3 player is given to show the usefulness of the proposed VP system.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.5
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• pp.2689-2698
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• 2013

Epithelial-to-mesenchymal transition (EMT) is a collection of events that allows the conversion of adherent epithelial cells, tightly bound to each other within an organized tissue, into independent fibroblastic cells possessing migratory properties and the ability to invade the extracellular matrix. EMT contributes to the complex architecture of the embryo by permitting the progression of embryogenesis from a simple single-cell layer epithelium to a complex three-dimensional organism composed of both epithelial and mesenchymal cells. However, in most tissues EMT is a developmentally restricted process and fully differentiated epithelia typically maintain their epithelial phenotype. Recently, elements of EMT, specially the loss of epithelial markers and the gain of mesenchymal markers, have been observed in pathological states, including epithelial cancers. Increasing evidence has confirmed its presence in human colon during colorectal carcinogenesis. In general, chronic inflammation is considered to be one of the causes of many human cancers including colorectal cancer(CRC). Accordingly, epidemiologic and clinical studies indicate that patients affected by ulcerative colitis and Crohn's disease, the two major forms of inflammatory bowel disease, have an increased risk of developing CRC. A large body of evidence supports roles for the SMAD/STAT3 signaling pathway, the NF-kB pathway, the Ras-mitogenactivated protein kinase/Snail/Slug and microRNAs in the development of colorectal cancers via epithelial-tomesenchymal transition. Thus, EMT appears to be closely involved in the pathogenesis of colorectal cancer, and analysis refered to it can yield novel targets for therapy.

• Toxicological Research
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• v.31 no.2
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• pp.151-156
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• 2015

5-Fluorouracil (5-FU) is commonly used for the therapy of colon cancer; however, acquired resistance to 5-FU is a critical barrier to successful treatment and the primary cause of chemotherapy failure. Epithelial-mesenchymal transition (EMT) is a process whereby cells undergo alterations in morphology and molecular characteristics promoting tumor progression and metastasis. Accumulating evidence shows that transition from epithelial to mesenchymal phenotype in cancer cells is associated with their resistance to chemotherapy. However, it is still poorly understood whether EMT is involved in acquired resistance to 5-FU. In this study, we developed an in vitro cell model, 5-FU-resistant HT-29 colon cancer cells, and characterized the differences in cellular morphology and molecular alterations between parental and resistant cells. In accord with mesenchymal-like morphology of 5-FU-resistant HT-29 cells, the expression of the mesenchymal marker fibronectin was significantly increased in these cells in comparision with that in the parental cells. Of interest, we also found a marked increase in the expression of EMT-inducing transcription factors Twist, Zeb1, and Zeb2. Finally, 5-FU-resistant cells showed enhanced migration in comparison with parental HT-29. Taken together, these results indicate that EMT could be associated with 5-FU resistance acquired by HT-29 cells. A specific role of each transcription factor found in this study will require further investigation.

• Korean Journal of Social Welfare
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• v.45
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• pp.341-373
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• 2001

This study seeks to identify the reform of vocational education plans so as to bring about a seamless transition from school to work. It puts forward a number of suggestions based upon an analysis of vocational education policies in Korean and U.S. schools, concerning the government's role, partnerships between education and industry, the educational system, curriculum and work-based learning. First, not only government initiatives but also close partnerships between education and industry are essential to help vocational education in school the transition to employment. Education and industry should work closely together to standardize certificate related skills and to have these skills reflected in the curriculum. Also the government should strive to provide guidelines for work-based learning and formulate standards for supervision and evaluation. Second, to facilitate the school to work transition, comprehensive schools should be promoted so that students have access to a greater ranger of vocational education. At the same time, an assessment system that certifies a mastering of the basic skills of those who undergo the education should be introduced, and it should be related to earn these certificates. Third, standardized vocational skills should be included in the curriculum so that students can acquire skills that are useful for industry. All the students in vocational and general high schools should have access both to general education, the foundation for lifelong learning and for employ ability, and to basic occupational skills which empower students in dealing with rapid changes of technology. Also a range of specialized vocational curricula should be offered so that students can opt for more specialized occupations; and they can select careers appropriate to their capability. Fourth, so that all students to have the opportunity to take part in work-based education, which is closely related to employment, various work-based learning programs should be offered to meet the needs of students and their educational conditions. Companies should for their part train students thoroughly in accordance with the standards of work-based education. In addition, supervisors should be stationed both in schools and companies in order to administer the students' work-based learning.

• Korea journal of population studies
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• v.35 no.1
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• pp.211-238
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• 2012

Using data from Korean Longitudinal Study on Aging (KLoSA), this study examines how continuity and change of marital status is associated with health over time among older women, focusing on the moderating effects of age and parent-child relationships. KLoSA data set has two waves of interviews, and for this study, 2046 women aged 65 and over were selected. To analyze data, Structural Equation Modeling (SEM) was used. The major findings are as follows. First, there was no statistically significant difference in health between continuously married older women and continuously single older women. However, older women who had transition from being married to being single showed lower physical health than continuously married and continuously single older women. Second, there were statistically significant differences in the effect of marital status on mental health according to the age of older women. Older women who had transition from being married to being single showed lower mental health than continuously married elders when older women were younger. Third, contact with children moderated the effect of marital status on physical health. Older women who had transition from being married to being single showed lower physical health than continuously single and continuously married older women when older women had less contact with their children. The findings imply after the loss of marital role, older women's relationship with adult children plays a significant role in promoting health. In conclusion, the findings of this study show the different pathways through which marital status is associated with health for 3 different groups of older women, being continuously single, being continuously married, and making transition from being married to being single.

• BMB Reports
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• v.41 no.10
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• pp.733-738
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• 2008

Although previous studies have implicated a role for TC1 (C8orf4) in cancer cell proliferation, the molecular mechanism of its action is still largely unclear. In this study, we showed, for the first time, that the mRNA levels of TC1 were upregulated by mitogens (FBS/thrombin) and at least partially, through the ERK1/2 signaling pathway. Interestingly, the over-expression of TC1 promoted the $G_1$- to S-phase transition of the cell cycle, which was delayed by the deficiency of ERK1/2 signaling in fibroblast cells. Furthermore, the luciferase reporter assay indicated that the over-expression of TC1 significantly increased Cyclin D1 promoter-driven luciferase activity. Taken together, our findings revealed that TC1 was involved in the mitogen-activated ERK1/2 signaling pathway and positively regulated $G_1$- to S-phase transition of the cell cycle. Our results may provide a novel mechanism of the role of TC1 in the regulation of cell proliferation.

• Korean journal of communication and information
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• v.18
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• pp.269-303
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• 2002

This article presents a historical account of media role in the transition and consolidation period of democracy. Despite the assumption that media plays a important role in the construction of democracy, it is less clear how the media can affect the process of political change itself. This article seeks to answer some of these question, based on the Mill's macro-social comparative 'method of difference' of Korea and Spain. It is widely agreed that both states achieve democracy through transaction from above(pacts). Media role, however, differs significantly in accordance with authoritarian legacies and civic representativeness of the pacts. Whereas Korean dailies is deepening given market oligopoly and prior practices after democratization, Spain dailies market entirely changed in both structural and spiritual respects. As a result, Korean dailies substantially lacks in civic representativeness as before, contrary to Spain. Spain television settled a sort of the external pluralism. Korean television is pursuing the BBC type of internal pluralism. In Korea, television is more commercial than Spain. Consequently, Spain media serve the consolidation of democracy more than Korea on the whole.

• Proceedings of the KIEE Conference
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• 2004.07e
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• pp.92-95
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• 2004

Power transformer is an important apparatus in transforming and delivering the power in a power system. It shows less accident ratio than other system apparatus, but once the accident occurs, it causes long-term operation stoppage and economic loss. It brings high bad spillover effects. Therefore, the role of protective relaying, which is to prevent internal fault a power transformer is highly important. This study proposed advanced algorithm that can clearly determine internal fault of the power transformer and magnetizing inrush, through numerical analysis by using the terminal voltage and input output current.