• Asian Pacific Journal of Cancer Prevention
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• v.16 no.9
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• pp.3901-3905
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• 2015

Objective: Our aim was to investigation the roles of MHC class I chain-related gene A(MICA) and natural killer cell group 2D(NKG2D) in human renal cancer cells. Materials and Methods: The expression of membrane MICA (mMICA) on renal cells and NKG2D on NK cells were detected by flow cytometry (FCM); the content of sMICA were detected by enzyme linked immunosorbent assay (ELISA) and the distribution of mMICA on renal tumor tissues by immunohistochemistry; the interaction between MICA and NKG2D was observed by antibody closed method. Results: Our results showed that the expression of mMICA in renal cancer tissues was significantly higher than in controls, where the soluble MICA was not expressed. Cytotoxic activity of NK cells was significantly reduced after exposure to NKG2D and MICA antibodies (P<0.05), and serum containing sMICA can obviously lower the function of NKG2D (P<0.05). Conclusions: The interaction of mMICA and NKG2D play important roles in mediation of cytotoxicity of NK cells in RCC. On the other hand, sMICA may mediate tumor immune escape through down- regulated NKG2D expression.

• Journal of Electrical Engineering and information Science
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• v.2 no.3
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• pp.71-76
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• 1997

A lot of experiments and analyses have been done to determine the aging mechanism of mica-epoxy composite material used for large generator stator windings in order to estimate remaining life of the generator for last decades. After degrading artificially the mica-epoxy composite material, the surface analysis is performed to analyze breakdown mechanism of insulation in air and hydrogen atmosphere; i) In the case of air atmosphere, it is observed that an aging propagation from conductor to core by partial discharge effect and the formation of cracks between layers is widely carbonized surface. ii) In case of hydrogen atmosphere, the partial discharge effect is reduced by the hydrogen pressure (4kg/$\textrm{cm}^2$). Potassium ions forming a sheet of mica is replaced by hydrogen ions, which can lead to microcracks. It is confirmed that the sizes of crack by SEM analysis are 10∼20[$\mu\textrm{m}$] in length under air, and 1∼5[$\mu\textrm{m}$] in diameter, 10∼50[$\mu\textrm{m}$] in length under hydrogen atmosphere respectively. The breakdown mechanism of sttor winding insulation materials which are composed of mica-epoxy is analyzed by the component of materials with EDS, SEM techniques. We concluded that the postassium ions of mica components are replaced by H\ulcorner, H$_3$O\ulcorner at boundary area of mica-epoxy and/or mica-mica. It is proposed that through these phenomena, the conductive layers of potassium enable creation of voids and cracks due to thermal, mechanical, electrical and environmental stresses.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.4
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• pp.1715-1717
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• 2014

The overall incidence and mortality of renal cell carcinoma (RCC), the most common kidney cancer, are steadily increasing for reasons that are not fully explained. Our aim was to explore the expression of membrane MHC class I chain-related gene A (mMICA) in human RCC cell lines and tissue specimens, and to determine expression of soluble MICA (sMICA) in serum of patients with renal cell carcinoma, we used flow cytometry (FCM) and immunohistochemistry as well as an enzyme linked immunosorbent assay (ELISA). The results showed that percentage of mMICA expression was significantly increased in human kidney cancer tissues and RCC cell lines (786-O and Ketr-3) than that in healthy adults and human embryonic kidney 293 (HEK293) cell line individuality (P<0.05). sMICA content in healthy adults was negative, but in renal cancer patients was significantly elevated (P<0.05). Our research showed that high expression of MICA in human kidney cancer, this results show that MICA might serve as potential tumor-associated antigen (TAA) in RCC.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.58-64
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• 2004

The shrinkages of injection molded parts are different in molding operational conditions, resins and additives. The shrinkage of injection molded part for crystalline polymer, PBT (polybutylene terephthalate) has been studied for various operational conditions of injection molding and content of additives. Mica was used as a additive to PBT to examine the part shrinkage according to the mica content. The part shrinkages of mica contained PBT decreased as mica content increases. Higher injection temperature and injection pressure resulted in a lower shrinkage. As mold temperature increases the part shrinkage decreased. The part shrinkage of flow direction was less than that of the perpendicular direction to the flow for both pure and mica contained PBT. However the shrinkage difference between flow and perpendicular to flow directions decreased as mica content increased.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.2
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• pp.715-718
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• 2012

The current research concerns the clinicopathological significance of MHC class I chain-related protein A (MICA) expression in oral squamous cell carcinomas (OSCCs). The expression and location of MICA protein in 14 normal oral mucous and 45 cancerous and para-cancerous tissues were assessed by immunohistochemistry and levels of MICA mRNA expression in 29 cancerous and para-cancerous tissues were determined by the real-time polymerase chain reaction. Data were analyzed with the SPSS16.0 software package. MICA was found to be located in the cytoplasm and plasma membrane. Expression was higher in para-cancerous than in cancerous tissues (P < 0.05). However, no statistical difference was found between the following: 1) para-cancerous tissue with normal mucosa; 2) normal mucosa with cancerous tissue;and 3) among different clinicopathological parameters in OSCC (P > 0.05). The level of MICA mRNA was higher in OSCCs than in para-cancerous tissues, and was correlated with the regional lymph node status and disease stage (P < 0.05). The levels of MICA protein and mRNA expression differ among normal oral mucosa, para-cancerous tissue, and cancerous tissue. MICA may contribute to the tumorigenesis and progression of OSCC.

• Transactions on Electrical and Electronic Materials
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• v.13 no.4
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• pp.200-203
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• 2012

Epoxy/mica composite was synthesized, in order to use it as an impregnation resin in a vacuum pressure impregnation (VPI) process, for manufacturing a high voltage rotary machine. The average particle size of the mica was 5~7 ${\mu}m$ and its content was 0, 20, 30 and 40 wt%. A plasticizer or a low molecular aliphatic epoxy was also used, to decrease the viscosity of the composite. The AC electrical breakdown strength was estimated in sphere-to-sphere electrodes, and the electrical breakdown data were estimated by Weibull statistical analysis. The electrical breakdown strength became higher with the addition of mica; and that of the system with 20 wt% mica was highest. The electrical breakdown strength of the system with an aliphatic epoxy was higher than that of the system with a, plasticizer.

• Current Applied Physics
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• v.18 no.12
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• pp.1486-1491
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• 2018

In recent years, mica has been successfully used as a substrate for the growth of flexible epitaxial ferroelectric oxide thin films. Here, we systematically investigated the flexibility of mica in terms of its thickness, repeated bending/unbending, extremely hot/cold conditions, and successive thermal cycling. A $20-{\mu}m-thick$ sheet of mica is flexible even up to the bending radius of 5 mm, and it is durable for 20,000 cycles of up- and down-bending. In addition, the mica shows flexibility at 10 and 773 K, and thermal cycling stability for the temperature variation of ca. 400 K. Compared with the widely used flexible polyimide, mica has a significantly higher Young's modulus (ca. 5.4 GPa) and negligible hysteresis in the force-displacement curve. These results show that mica should be a suitable substrate for piezoelectric energy-harvesting applications of ferroelectric oxide thin films at extremely low and high temperatures.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.216-219
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• 1987

Dielectric and Mechanical Properties of Mica flake/ Epoxy Composite are investigated. The Mica content is about 50 wt % and its thickness is about $240{\mu}m$. The finished Mica flake/Epoxy Composite contains about 0.1-1.0 wt % of aminosilane coupling agent. Ruby Mica filler and high temperature curing Epoxy resin are used. From the viewpoint of dielectric and mechanical properities. the optimum properties is obtained for the sample post cured at $130^{\circ}C$ for 5 h ours after curing at $80^{\circ}C$ for 2 hours and with 0.5 weight % silane coupling agent.

• Economic and Environmental Geology
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• v.34 no.6
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• pp.583-593
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• 2001

Clay minerals are common component of fault gouge and have been used to determine the fault activity age using K-Ar dating technique. We carried out XRD and K-Ar analyses of the mica clay minerals from the fault gouge along the Ulsan Fault Zone, southeastern Korea to estimate the timing of the major fault activity. Mica clay minerals for four grain size fractions of 5-2 Um, 2-1 $\mu$m, 1-0.35$\mu$m, and 0.35-0.05 $\mu$m were separated from the gouge samples in the three locations by the hydraulic elutriation and contrifugal separator. Fault gouges are composed of smectite, mica clay minerals, kaolinite, chlorite, quartz, and feldspar. The illite crystallinity of mica clay minerals is the highest in the finest grained fraction with lM polytype, indicating that the aulhigenic mica clay minerals have been concentrated in the fraction. K-Ar ages give some variation from 46 to 35 Ma (330-2), 45 to 39 Ma (16Ww), and 32 to 15 Ma (102Ws) and are the youngest in the finest grained fraction. These results suggest that the hydrothermal alteration associated with the major fault activities along the Ulsan fault Zone took place twice at 39-35 Ma and 15 Ma.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.10
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• pp.1888-1894
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• 2011

In this study, large-current (75 - 400 A), high-voltage (500 - 1000 $V_{rms}$), reliable capacitors with capacitances (C) of 100 - 1000 nF were developed for energy storage facility applications. Mica was used as the dielectric of the capacitors. In order to form a parallel stack of a capacitor element, 50 ${\mu}m$ thick mica sheets with a size of $30mm{\times}35mm$ were used with lead foils for the plate lead type of mica capacitors (HCM-L), while the same sizes of mica sheets coated by Ag paste were employed with lead foils for the parallel plate terminal type (HCM-C). The developed capacitors exhibited well behaviored device characteristics which meet the requirements of the capacitors. The developed capacitors also showed excellent characteristics for thermal shock test. The stability characteristics of developed capacitors for large current stress was superior to those measured for the capacitors prepared recently by CDETm.