• Journal of the Korean Geotechnical Society
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• v.16 no.1
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• pp.145-155
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• 2000

Orientation data of discontinuities are of paramount importance for rock slope stability studies because they control the possibility of unstable conditions or excessive deformation. Most orientation data are collected by using linear sampling techniques, such as borehole fracture mapping and the detailed scanline method (outcrop mapping). However, these data, acquired by the above linear sampling techniques, are subjected to bias, owing to the orientation of the sampling line. Even though a weighting factor is applied to orientation data in order to reduce this bias, the bias will not be significantly reduced when certain sampling orientations are involved. That is, if the linear sampling orientation nearly parallels the discontinuity orientation, most discontinuities orientation data which are parallel to sampling line will be excluded from the survey result. This phenomenon can cause serious misinterpretation of discontinuity orientation data because critical information is omitted. In the case study, orientation data collected by using the borehole fracture mapping method (vertical scanline) were compared to those based on orientation data from the detailed scanline method (horizontal scanline). Differences in results for the two procedures revealed a concern that a representative orientation of discontinuities was not accomplished. Equal-area, polar stereo nets were used to determine the distribution of dip angles and to compare the data distribution fur the borehole method versus those for the scanline method.

• Progress in Medical Physics
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• v.20 no.3
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• pp.125-131
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• 2009

In this study, the paclitaxel eluting stent (PES) was prepared by coating a biliary stent with paclitaxel using various biopolymer such as poly (vinyl acetate) (PVAc), poly (lactic-co-glycolic acid) (PLGA), Silicone rubber for restenosis prevention in gastrointestinal disease by a dip-coating method. Drug contents of PES were increased as surface area of stent, concentration and molecular weight of coating polymer increase. In $^1H-NMR$ specta, we know that drug did not change by confirming specific peaks of paclitaxel in PES. As shown in SEM image, PES prepared using various biopolymer is coated clearly and regularly except Silicone rubber coating polymer. In in vitro cell cytotoxicity test, bare stent showed low cytotoxic effect against CT-26 colon carcinoma cell line on 3 day. However, PES coated with PLGA 502H showed the highest cytotoxicity because PLGA 502H is biodegradable polymer and has less molecular weight than other coating polymer. These results suggest that PES coated various biopolymer can be prevented restenosis in gastrointestinal disease.

• Molecules and Cells
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• v.41 no.11
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• pp.953-963
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• 2018

The stepwise development of T cells from a multipotent precursor is guided by diverse mechanisms, including interactions among lineage-specific transcription factors (TFs) and epigenetic changes, such as DNA methylation and hydroxymethylation, which play crucial roles in mammalian development and lineage commitment. To elucidate the transcriptional networks and epigenetic mechanisms underlying T-cell lineage commitment, we investigated genome-wide changes in gene expression, DNA methylation and hydroxymethylation among populations representing five successive stages of T-cell development (DN3, DN4, DP, $CD4^+$, and $CD8^+$) by performing RNA-seq, MBD-seq and hMeDIP-seq, respectively. The most significant changes in the transcriptomes and epigenomes occurred during the DN4 to DP transition. During the DP stage, many genes involved in chromatin modification were up-regulated and exhibited dramatic changes in DNA hydroxymethylation. We also observed 436 alternative splicing events, and approximately 57% (252) of these events occurred during the DP stage. Many stage-specific, differentially methylated regions were observed near the stage-specific, differentially expressed genes. The dynamic changes in DNA methylation and hydroxymethylation were associated with the recruitment of stage-specific TFs. We elucidated interactive networks comprising TFs, chromatin modifiers, and DNA methylation and hope that this study provides a framework for the understanding of the molecular networks underlying T-cell lineage commitment.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.6
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• pp.585-592
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• 2011

The enhancement of the cold-start capability of polymer electrolyte fuel cells is of great importance in terms of the durability and reliability of fuel-cell vehicles. In this study, vanadium oxide films deposited onto the flat surface of metallic bipolar plates were synthesized to investigate the feasibility of their use as an efficient self-heating source to expedite the temperature rise during startup at subzero temperatures. Samples were prepared through the dip-coating technique using the hydrolytic sol-gel route, and the chemical compositions and microstructures of the films were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and field-emission scanning electron microscopy. In addition, the electrical resistance hysteresis loop of the films was measured over a temperature range from -20 to $80^{\circ}C$ using a four-terminal technique. Experimentally, it was found that the thermal energy (Joule heating) resulting from self-heating of the films was sufficient to provide the substantial amount of energy required for thawing at subzero temperatures.

• Korean journal of applied entomology
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• v.32 no.3
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• pp.300-306
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• 1993

The CryIIA gene encoding the insecticidal crystal protein of Bacillus thuringiens!s subsp. kurstalri HD-l has been cloned in Escherichia col!, and its nucleotide sequences were determined completely. 5kb Hindlli fragment harboring CryIIA gene was screened in the large ca. 225kb plasmid DNA by southern blot. HindlIT digested 5kb fragment was ligated into pUC19 and transformed in E. coli. The 4kb BamHI-HindlIT fragment containing the CryIIA gene was subcloned and named pSKIIA. DNA sequence analysis demonstrates that pSKIIA is the gene of an operon which is comprised of Lhree open reading frames (designated orn, orf2 and or£3). The CrylIA gene is composed of 3,952bp-long BamHI-Hindill DNA restriction fragment. The orf3 code for a polypeptide of 633 amino acid residues. The protoxin protein has a predicted molecular weight of 70,780. The E. coli derived protoxin gene product is biologICally active against three species of Lepidopteran (Plu.lelia maculipennis, He/iolhis assulta, Spodoptera litura) and a species of Dip Leran( Culex pipines) larvae in bioassay.

• Economic and Environmental Geology
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• v.24 no.4
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• pp.421-434
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• 1991

Ground magnetic surveys were conducted at four areas where the Yangsan fault, the most prominent lineament in the Kyeongsang basin, appears to be passed through. For data processing, IGRF correction, upward continuation and reduction-to-the-pole were performed. The automatic inversion by using a matrix computation method, which takes the depth to bottom layer of the horizontal two layer structure as the model parameter, has been attempted to delineate the subsurface structure. Upward continuation of the surface magnetic map to the same level of the aeromagnetic survey (KIER, 1989) resulted in very similiar patterns to those of aeromagnetic data. Subsurface modeling of eight profile data show that the strike and dip of the Yangsan fault in study areas are $N6^{\circ}-15^{\circ}E$, and near vertical to somewhat eastward, repectively, despite of the local lithological contrast of each study area. It seems that the magnetic effect of faulting in the study area 1, which locates in the most northern part of the survey areas, is disturbed by that of igneous intrusion. At study area 2, the possibility of volcanic or igneous intrusion, which is 200-300 meters wide along the fault plane was presented. At study area 3, unlike other study areas, distinct fracture zone of 500-700 meters in width was revealed along the surface fault line. The andesitic rocks of the study area 4 have very high susceptibilities and the fault line on surface of this area was shifted about 500 meter eastward, as compared with the inferred fault line by the previous study.

• Tunnel and Underground Space
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• v.21 no.3
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• pp.151-163
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• 2011

The LCM test is one of the most powerful and reliable methods for designing the disc cutter and for predicting the TBM (Tunnel Boring Machine) performance. It has an advantage to predict the actual load on disc cutter from the laboratory test on the real-size large rock samples, however, it also has a disadvantage to transport and/or prepare the large rock samples and to need an extra cost for experiment. Moreover it is not easy to execute the test for jointed rock mass, and sometimes the design model estimated from the test can not be applied to the real design of disc cutter. In order to break this critical point, lots of numerical studies have been performed. PFC2D can simulate crack propagation and rock fragmentation effectively, because it is useful in particle flow analysis. Consequently, in this study, the PFC2D has been adopted for numerical analysis on cutting power of disc cutter according to the different angle of joint, the different direction of joint, and the different space of joint with jointed rock mass models. From the numerical analyses, it was concluded that the bigger cutting power of disc cutter was needed for reverse cutting direction to joint rather than for forward direction, and the cutting power of disc cutter was increased with decreasing the dip angle of joint and decreasing the space of joints in reverse cutting direction. The more precise numerical model for disc cutter can be developed from comparison between the numerical results and LCM test results, and the resonable guideline is expected for prediction of TBM performance and disc cutter.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.3
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• pp.271-277
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• 2000

Transparent $TiO_2$ thin films were prepared by the sol-gel method from titanium alkoxide aqueous solution containing large quantities of water. To prepare the aqueous system sol, the chelate compound solution were prepared from each 1 mole of titanium(IV)iso-propoxide, acetylacetone and 8 moles of isopropyl-alcohol. And then the 50 moles aqueous solution with the 0.02~0.50 moles of HCI for sol stability and the 0.3 mole of polyethylene glycol for coating adhesion were precisely dropped on the chelate compound solution. $TiO_2$thin films were fabricated by dip coating, drying and heat treatment at $400^{\circ}C$ and their characteristics were investigated by XRD, SEM and UV-visible spectrometer, The neutral sol of composition with TTIP : AcAc : IPA : $H_2O$ : PEG : HCl = 1 : 1 : 8 : 50 : 0.3 : 0.15 (molar ratio) was maintained stable sol condition and without problem for coating more than 30 days. The anatase phase $TiO_2$thin film prepared from 30 times dipping, drying and heat treating showed the flat surface and the fine microstructure of fracture surface with about 2 $\mu\textrm{m}$ thickness. Transparency of these $TiO_2$thin film was 80 % in the visible region.

• Journal of the Korean Geotechnical Society
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• v.30 no.9
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• pp.41-55
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• 2014

In performing seismic analysis of tunnels, it is a common practice to ignore the rock joints and to assume that the rock mass surrounding the tunnel is continuous. The applicability of this assumption has not yet been validated in detail. This study performs a series of pseudo-static discrete element analyses to evaluate the effect of rock joint on the seismic response of tunnels. The parameters considered are joint intersection location, joint spacing, joint stiffness, joint dip, and interface stiffness. The results show that the joint stiffness has the most critical influence on the tunnel response. The tunnel response increases with the spacing, resulting in localized concentration of moment and shear stress. The response of the tunnel is the lowest for joints dipping at $45^{\circ}$. This is because large shear stresses result in rotation of the principal planes by $45^{\circ}$. In summary, the weathered and smooth, vertical or horizontal, and widely spaced joint set will significantly increase the tunnel response under seismic loading. The tunnel linings are shown to be most susceptible to damage due to induced shear stress, and therefore should be checked in the seismic design.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.4
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• pp.522-530
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• 2009

The purpose of this study was to evaluate the clinical effectiveness of new streptococcus detection system which used monoclonal antibody against Streptococcus mutans. 92 children aged between 2 and 8 were involved in this experiment and their saliva samples were collected for testing. Streptococcus mutans were measured by both monoclonal antibody-based detecting system (Saliva-$check^{TM}$ Mutans) and dip slide detecting system($Dentocult^{TM}$-SM). The results showed that Saliva-$check^{TM}$ Mutans levels had a significant correlation with dfs rate of subjects and the two test kits, Saliva-$check^{TM}$ Mutans and $Dentocult^{TM}$-SM were shown to have a good correlation although they were based on different mechanism.