• International Journal of Aeronautical and Space Sciences
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• v.18 no.2
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• pp.215-221
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• 2017

An electromagnetic (EM) wave absorber reduces the possibility of radar detection by minimizing the radar cross section (RCS) of structures. In this study, a radar absorbing structure (RAS) was applied to the leading edge of a blended wing body aircraft to reduce RCS in X-band (8.2~12.4GHz) radar. The RAS was composed of a periodic pattern resistive sheet with conductive lossy material and glass-fiber/epoxy composite as a spacer. The applied RAS is a multifunctional composite structure which has both electromagnetic (EM) wave absorbing ability and load-bearing ability. A two dimensional unit absorber was designed first in a flat-plate shape, and then the fabricated leading edge structure incorporating the above RAS was investigated, using simulated and free-space measured reflection loss data from the flat-plate absorber. The leading edge was implemented on the aircraft, and its RCS was measured with respect to various azimuth angles in both polarizations (VV and HH). The RCS reduction effect of the RAS was evaluated in comparison with a leading edge of carbon fabric reinforced plastics (CFRP). The designed leading edge structure was examined through static structural analysis for various aircraft load cases to check structural integrity in terms of margin of safety. The mechanical and structural characteristics of CFRP, RAS and CFRP with RAM structures were also discussed in terms of their weight.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.8
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• pp.3505-3508
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• 2015

Background: Ras genes are thought to play an important role in human cancer since they have been found to be activated frequently in several types of tumors including breast cancer, where the overall incidence of K-RAS oncogene activation is 0-10%. Evaluation of K-RAS gene not only for mutational frequency but also for mutation types in this downstream signaling gene pathway is necessary to determine the mechanisms of action. The present study was conducted to test the hypothesis that K-RAS activation is involved in breast cancer risk of south Indian population. Materials and Methods: A total of 70 paired pathologically confirmed tumor and non-tumor tissues from the same breast cancer patients were analysed for most common K-RAS mutations of codon 12,13 and 61 by polymerase chain reaction followed by restriction digestion and direct nucleotide sequencing method. Results: We found that a high rate of homozygous and heterozygous mutations of codon 12, but not codon 13 and 61, may influence the invasive ductal carcinoma of breast risk in this study. Conclusions: Our study indicated that only codon 12 may be involved in initiating breast carcinogenesis in India.

• The Korean Journal of Quaternary Research
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• v.21 no.2
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• pp.56-57
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• 2007

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.327.3-328
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• 2002

Transforming growth factor-${\beta}$ (TGF-${\beta}$), a hormonally active polypeptide found in normal and transformed tissues. regulates cellular growth and phenotyphic plasticity. We have previously shown that H-ras. but not N-ras. induces invasive phenotype in MCF10A human breast epithelial cells. In this study. we wished to examine the effect of TGF-${\beta}$ on H-ras-induced invasion and motility in MCFI 10A cells by performing in vitro invasion assay and wound migration assay. (omitted)

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.4
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• pp.437-440
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• 1999

New method of control based upon a physical model of the Stepanov growth technique has been developed. The controller keeps the system stable and completely denies operator's interference into the process. The system demonstrates very reliable results under commercial production of shaped sapphire crystals.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2001.09a
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• pp.13-15
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• 2001

발암성시험연구에 사용되고 있는 형질전환 동물들은 랫드와 마우스 등이 있는데, 그 중 c-Ha-ras proto-oncogene 마우스 (ras H2 mice), v-Ha-ras 형질전환 마우스 (Tg.AC mice), pim-1 형질전환 마우스 및 p53 knockout 마우스 등이 발암유발물질에 감수성이 높아 현재 중기발암성시험에 이용되고 있다. (중략)

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1736-1737
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• 2007

Significant increase of container flows in marine terminals requires more efficient automatic port systems. This paper presents a novel routing and collision avoidance algorithm of linear motor based shuttle cars using random access sequence dynamic programming (RAS DP). The proposed RAS DP is accomplished online for determining optimal paths for each shuttle car.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.141-141
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• 2003

Ras expression has been suggested as a marker for tumor aggressiveness of breast cancer, including the degrees of invasion and tumor recurrence. We previously showed that p38 MAPK is a key signaling molecule differentially regulated by H-ras and N-ras, leading to H-ras-specific cell invasive and migrative phenotypes in human breast epithelial cells (Cancer Res.: 63, 5454-5461, 2003).(omitted)

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.223.1-223.1
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• 2003

Many studies have identified the phosphatidylinositol 3-kinase (PI3K) as a key regulator for various cellular functions including cell survival, growth and motility. We have previously shown that H-ras, but not N-ras. induces invasiveness and motility in human breast epithelial cells (MCF10A), while both H-ras and N-ras induce transformed phenotype. In the present study, we wished to investigate the functional role of PI3K pathway in H-ra-induced invasive phenotype and motility of MCF10A cells. (omitted)

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.170.2-170.2
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• 2003

Ras expression has been suggested as a marker for tumor aggressiveness of breast cancer, including the degrees of invasion and tumor recurrence. We previously showed that p38 MAPK is a key signaling molecule differentially regulated by H-ras and N-ras, leading to H-ras-specific cell invasive and migrative phenotypes in human breast epithelial cells (Cancer Res: 63, 5454-5461, 2003). In this study, we further investigated the role of p38 MARK pathway in the induction of metastatic potential in MCF10A cells as a "gain of function" study. (omitted)