• 한국정밀공학회지
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• 제29권10호
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• pp.1056-1061
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• 2012

FEM analysis is essential to shorten the development time and reduce the cost for developing high-performance machine tools. Mount joint parts play important role to ensure static and dynamic stability of machine tools. This paper suggests a computational modeling of mount joint part of machine tools. MATRIX27 element of ANSYS is adopted to model mount joint parts. MATRIX27 allows the definition of stiffness and damping matrices in matrix form. The matrix is assumed to relate two nodes, each with six degrees of freedom per node. Stiffness and damping values of commercial mount products are measured to build a database for FEM analysis. Jack mounts with rubber pad are exemplified in this paper. The database extracted from the experiments is also used to estimate of stiffness and damping of untested mounts. FEM analysis of machine tools system with the suggested mount computational model is performed. Static and dynamic results prove the feasibility of the suggested mount model.

• 생명과학회지
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• 제6권4호
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• pp.286-292
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• 1996

Angiogenesis is a fundamental process by which new blood vessels are formed. It is essential in embryo development, and wound healing. Furthermore, malignant tumor growth and metastasis are also angiogenesis-dependent. In the catilage tissue, normal angiogenesis process is suppressed. In fact, it was reported that angiogenesis-inhibitory substances were isolated from the extracts of cow and shark catilage tissue. In order to isolate genes involved in the regulation of angiogenesis from a catilage fish, we constructed a shark cDNA library from Scylliohinus torazame. We then screened the library using hyman tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) gene as a probe. Among the 4 X 10$^{4}$ plaques screened, we isolated 2 positive clones (T-1, T-2). Restriction enzyme analysis revealed that the T-1 clone contains 0.8 kb cDNA insert, and the T-2 clone contains 1.2 kb and 2.2 kb inserts, respectively. Further DNA sequence analysis shows that the DNA sequence of the T-1 clone is 53% homologous to that of the human TIMP-1 gene.

• BMB Reports
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• 제41권12호
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• pp.858-862
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• 2008

Membrane-type 1 matrix metalloproteinase (MT1-MMP) is a zinc-dependent proteinase found in cholesterol-rich lipid rafts on the plasma membrane. MT1-MMP hydrolyzes extracellular matrix (ECM) proteins, activates pro-matrix metalloproteinase-2 (proMMP-2) and plays an important role in ECM remodeling, cancer cell migration and metastasis. The role of caveolin-1, an integral protein of caveolae, in the activation of MT1-MMP remains largely unknown. Here, we show that the expression of caveolin-1 attenuates the activation of proMMP-2, reduces proteolytic cleavage of ECM and inhibits cell migration. We utilized the cytoplasmic tail domain deletion (${\Delta}CT$) or the E240A mutant of MT1-MMP. Co-expression of caveolin-1 with the wild-type or the ${\Delta}CT$ MT1-MMP decreased the proMMP-2 activation and inhibited collagen degradation and cell migration. Caveolin-1 had no effect on the catalytically inert E240A MT1-MMP. Our findings suggest that caveolin-1 is essential in the down-regulation of MT1-MMP activity by promoting internalization from the cell surface.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.362-365
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• 2005

Currently Chemical Mechanical Planarization (CMP) has become an essential step in the overall semiconductor wafer fabrication technology. Especially the CMP pad conditioner, one of the diamond tools, is required to have strong diamond retention. Strong cohesion between diamond grits and metal matrix prevents macro scratch on the wafer. If diamond retention is weak, the diamond will be pulled out of metal matrix. The pulled diamond grits are causative of macro scratch on wafer during CMP process. Firstly, some results will be reported of cohesion between diamond grits and metal matrix on the diamond tools prepared by three different manufacturing methods. A measuring instrument with sharp cemented carbide connected with a push-pull gauge was manufactured to measure the cohesion between diamond grits and metal matrix. The retention force of brazed diamond tool was stronger than the others. The retention force was also increased in proportion to the contact area of diamond grits and metal matrix. The brazed diamond tool has a strong chemical combination of the interlayer composed of chrome in metal matrix and carbon which enhance the interfacial cohesion strength between diamond grits and metal matrix. Secondly, we measured real-time data of the coefficient of friction and the pad wear rate by using CMP tester (CETR, CP-4). CMP pad conditioner samples were manufactured by brazed, electro-plated and sintered methods. The coefficient of friction and the pad wear rate were shown differently according to the arranged diamond patterns. Consequently, the coefficient of friction is increased according as the space between diamonds is increased or the concentration of diamonds is decreased. The pad wear rate is increased according as the degree of diamond protrusion is increased.

• Interdisciplinary Bio Central
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• 제6권4호
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• pp.3.1-3.10
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• 2014

Amino acid substitution matrices are essential tools for protein sequence analysis, homology sequence search in protein databases and multiple sequence alignment. The PAM matrix was the first widely used amino acid substitution matrix. The BLOSUM series then succeeded the PAM matrix. Most substitution matrixes were developed by using the statistical frequency of substitution between each amino acid at blocks representing groups of protein families or related proteins. However, substitution of amino acids is based on the similarity of physiochemical properties of each amino acid. In this study, a new approach was used to obtain major physiochemical properties in multiple sequence alignment. Frequency of amino acid substitution in multiple sequence alignment database and selected attributes of amino acids in physiochemical properties database were merged. This merged data showed the major physiochemical properties through principle components analysis. Using factor analysis, these four principle components were interpreted as flexibility of electronic movement, polarity, negative charge and structural flexibility. Applying these four components, BAPS was constructed and validated for accuracy. When comparing receiver operated characteristic ($ROC_{50}$) values, BAPS scored slightly lower than BLOSUM and PAM. However, when evaluating for accuracy by comparing results from multiple sequence alignment with the structural alignment results of two test data sets with known three-dimensional structure in the homologous structure alignment database, the result of the test for BAPS was comparatively equivalent or better than results for prior matrices including PAM, Gonnet, Identity and Genetic code matrix.

• International Journal of Oral Biology
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• 제34권2호
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• pp.105-113
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• 2009

Dentin, a major component of teeth, is formed by odontoblasts which produce the dentin matrix beneath the dental epithelium and induce the mineralization of dentin. To date, the biochemical properties of dentin matrix proteins have been well characterized, but upstream regulators of these proteins are not yet well known. Recently in this regard, several transcription factors have been identified as potential regulators of matrix proteins. Most transcription factors are generally involved in diverse biological processes and it is essential to identify those that are odontoblast-specific transactivators to further understand the process of dentin formation. We thus analyzed the expression pattern of dentin matrix proteins and the activities of established transactivators containing a Cre-locus. Expression analyses using in situ hybridization showed that dentin matrix proteins are sequentially expressed in differentiating odontoblasts, including type-I collagen, Dmp-1 and Dspp. The activities of the transactivators were evaluated using ${\beta}$-galactosidase following the generation of double transgenic mice with each transactivator and the ROSA26R reporter line. The ${\beta}$-galactosidase activity of each transactivator paralled the expression of the matrix proteins. These results thus showed that these transactivators could be utilized for odontoblastspecific conditional gene targeting. In addition, time- and tissue-specific conditional gene targeting might also be achieved using a combination of these transactivators. Odontoblast-specific conditional gene targeting with these transactivators will likely also provide new insights into the molecular mechanisms underlying dentin formation.

• 동의신경정신과학회지
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• 제19권2호
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• pp.111-122
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• 2008

Objective : Herb medicines are potential sources of useful edible and medicinal plants. They are used as a drug because of their various biological activities such as immunomodulatory, antiviral, and antitumor functions. Nelumbo nucifera have been applied in Chinese herbal prescriptions to improve tissue inflammation. However, it has not been elucidated on the effect of the flower of Nelumbo nucifera in cells. Method : In the present study, to examine the effect of that on glioma cells, U87, the essential oil was extracted from the flower of Nelumbo nucifera (NN essential oil). U87 cells were exposed to different concentrations of 2-40 ug/ml of NN essential oil in ethanol. Cell viability was measured by MTT assay at 24 h. To find out the intracellular target signal molecule(s) for this antiproliferative activity of NN essential oil, phosphorylation of Akt, ERM, MAPK or p38 proteins were examined by Western blot analysis. To study long term effect of NN essential oil in U87 cells, the image of cells treated with NN essential oil for 4 days were obtained. Results and Conclusion : NN essential oil was shown to exhibit antitumor activity in glioma cells, at a broad range of concentrations of 10-40 ug/ml. The phosphorylation of Akt and Endoplasmic Reticulum Matrix (ERM) proteins which known to be involved in the cell death, were gradually decreased to 2 hours after addition 20 ug/ml of NN essential oil. However, the phosphorylation of mitogen-activated protein (MAPK) and p38 was found to increase in NN essential oil treated cells. NN essential oil treated cells showed decreased glioma cell number. These results provide a possible NN essential oil-induced inhibitory signal for tumor cell proliferation that is initiated by the decrease in Akt activity. Moreover, it is likely that the activation of p38 is required for the NN essential oil-induced inhibition of tumor proliferation.

• 한국인터넷방송통신학회논문지
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• 제8권3호
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• pp.57-70
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• 2008

This paper introduces a new paradigm of physical layer security through channel coding for wireless networks. The well known spread spectrum based physical layer security in wireless network is applicable when code division multiple access (CDMA) is used as wireless air link interface. In our proposal, we incorporate the proposed security protocol within channel coding as channel coding is an essential part of all kind of wireless communications. Channel coding has a built-in security in the sense of encoding and decoding algorithm. Decoding of a particular codeword is possible only when the encoding procedure is exactly known. This point is the key of our proposed security protocol. The common parameter that required for both encoder and decoder is generally a generator matrix. We proposed a random selection of generators according to a security key to ensure the secrecy of the networks against unauthorized access. Therefore, the conventional channel coding technique is used as a security controller of the network along with its error correcting purpose.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 추계 학술대회논문집
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• pp.183-186
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• 2005

We developed an upwind numerical formulation based on the eigenvalues of the approximate Jacobian matrix in order to solve the hyperbolic conservation laws governing the two-fluid two-phase flow models. We obtained eight analytic eigenvalues in the two dimensions that can be used for estimate of the wave speeds essential in constructing an upwind numerical method. Two-dimensional underwater cavitation in a flow past structural shapes or by underwater explosion can be solved using this method. We present quantitative prediction of cavitation for the water tunnel wall and airfoils that has both experimental data as well as numerical results by other numerical methods and models.

• 전기학회논문지
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• 제60권5호
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• pp.929-935
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• 2011

Customers hardly change to electric prices in old days because electricity is essential commodity, while demand changes with price after deregulation. It's explained by price-based demand response with demand-elasticity matrix. Also all of the customers have had identical demand-price elasticity matrix till now. But in a practical power system, various customers are present with taking a variety of demand-price elasticity. Therefore this paper proposes demand-price sensitivity to represent different demand-price elasticity. Also as proposing demand-reliability sensitivity, it is modeling various customers' characteristics to reliability. And then this paper calculates total expected interruption cost of customer from the customer interruption cost and the demand-reliability sensitivity. A total expected interruption cost of system is shown as opportunity cost of a generation cost.