• Journal of radiological science and technology
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• v.33 no.3
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• pp.289-294
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• 2010

The purpose of this study is an evaluation of the performance of a detector under radiographic irradiation condition by fabricating the polycrystalline $HgI_2$ film detector. The polycrystalline $HgI_2$ film detectors with thickness of 210 and $320\;{\mu}m$ were fabricated by screen print technology. Measurements of X-ray sensitivity and dark current were performed for two detectors. And measurements of the linearity of X-ray response and reproducibility were performed for the detector of thickness $320\;{\mu}m$. For applied electric field strengths from 0.05 to $2\;V/{\mu}m$ to the detector of thickness $320\;{\mu}m$, the X-ray sensitivities were measured from 233 to $1,408{\times}106\;electrons/mR{\cdot}mm^2$. And the dark currents were measured from 3.2 to $118\;pA/mm^2$. Compared with values reported by Zhong Su et al., the X-ray sensitivities exhibit about two times larger than the X-ray sensitivities measured by Zhong Su et al. And the dark currents exhibit about nine times larger than the dark currents measured by Zhong Su et al. The linearity of X-ray response acquired 0.988 as a coefficient of correlation (r). Reproducibility acquired 0.002 as a coefficient of variation. This study provides the performance data of fabricated polycrystalline $HgI_2$ film detector available for an active matrix flat panel imager under radiographic irradiation condition.

• Journal of Physiology & Pathology in Korean Medicine
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• v.26 no.5
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• pp.687-692
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• 2012

Schizandra chinensis extract has been known to possess a variety of efficacy including antitumor. However, it remains unclear how schizandrin, which is a major biological active ingredient of Schizandra chinensis, exerts antitumor effect. This study was designed to investigate the mechanism by which schizandrin inhibits tumor growth and metastasis. In in vivo test using tumor model mice injected with B16BL6 cell line, mice treated with 10 and 100 ${\mu}g/ml$ schizandrin showed a significant inhibition by $73.79{\pm}6.43%$ and $90.46{\pm}1.72%$, respectively, compared with positive tumor controls. Schizandrin did not exert a significant toxicity for the normal cells (HUVECs) and tumor cell lines (A549, B16BL6, Du145, Huh7). Treatment with schizandrin at 10 and 100 ${\mu}g$/head significantly inhibited the tumor-induced angiogenesis by $68.04{\pm}32.21%$ and $103.8{\pm}34.99%$ compared with the positive control group, respectively. Using in vivo lung metastasis model, tumor metastasis assay revealed that 10 and 100 ${\mu}g$/head schizandrin significantly decreased the metastatic lung tumor by $37.51{\pm}8.15%$ and $75.53{\pm}4.38%$ compared with positive controls, respectively. On the other hand, schizandrin did not affect the adherence of B16BL6 cell line to extracellular matrix protein. These results demonstrate that schizandrin exerts inhibitory effect on tumor growth and metastasis by inhibiting angiogenesis. This study thus suggest that schizandrin may be a candidate molecule target for cancer drug development.

• Korean Chemical Engineering Research
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• v.54 no.4
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• pp.574-581
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• 2016

In this study, CNT functionalized with pyrrolidine ring via 1,3-dipolar cycloaddition reaction with various amino acid and aldehyde was synthesized. Metallocene was subsequently immobilized on the functionalized CNT and CNT/polyethylene composite was prepared via in-situ ethylene polymerization. The polymerization activities of metallocene supported on CNT functionalized with glycine and benzaldehyde (Gly+BA-CNT) were similar to those of metallocene supported on CNT functionalized with N-benzyloxycarbonylglycine and paraformaldehyde (Z-Gly+PFA-CNT) although its Zr content was lower than that of Z-Gly+PFA-CNT. In the case of metallocene supported on Z-Gly+PFA-CNT, the even distribution of active sites hindered the diffusion of ethylene monomer and cocatalyst MAO due to steric hindrance during ethylene polymerization. Compared to polyethylene produced from homogeneous metallocene catalysts, CNT/PE composites had a higher initial degradation temperature ($T_{onset}$) and maximum mass loss temperature ($T_{max}$). It suggests that pyrrolidine functionalized CNT is uniformly dispersed and strongly interacted with the PE matrix, enhancing the thermal stability of PE.

• Biomolecules & Therapeutics
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• v.17 no.1
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• pp.70-78
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• 2009

Coptis japonica (C. japonica) is a perennial medicinal plant that has anti-inflammatory activity. C. japonica contains numerous biologically active alkaloids including berberine, palmatine, epi-berberine, and coptisine. The most well-known anti-inflammatory principal in C. japonica is berberine. For example, berberine has been implicated in the inhibition of iNOS induction by cytokines in microglial cells. However, the efficacies of other alkaloids components on microglial activation were not investigated yet. In this study, we investigated the effects of three alkaloids (palmatine, epi-berberine and coptisine) from C. japonica on lipopolysaccharide (LPS)-induced microglial activation. BV2 microglial cells were immunostimulated with LPS and then the production of several inflammatory mediators such as nitric oxide (NO), reactive oxygen species (ROS) and matrix metalloproteinase-9 (MMP-9) were examined as well as the phosphorylation status of Erk1/2 mitogen activated protein kinase (MAPK). Palmatine and to a lesser extent epi-berberine and coptisine, significantly reduced the release of NO, which was mediated by the inhibition of LPS-stimulated mRNA and protein induction of inducible nitric oxide synthase (iNOS) from BV2 microglia. In addition to NO, palmatine inhibited MMP-9 enzymatic activity and mRNA induction by LPS. Palmatine also inhibited the increase in the LPS-induced MMP-9 promoter activity determined by MMP-9 promoter luciferase reporter assay. LPS stimulation increased Erk1/2 phosphorylation in BV2 cells and these alkaloids inhibited the LPS-induced phosphorylation of Erk1/2. The anti-inflammatory effect of palmatine in LPS-stimulated microglia may suggest the potential use of the alkaloids in the modulation of neuroinflammatory responses, which might be important in the pathophysiological events of several neurological diseases including Alzheimer's disease (AD), multiple sclerosis (MS), Parkinson's disease (PD) and stroke.

• Journal of Life Science
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• v.25 no.12
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• pp.1370-1376
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• 2015

The 1, 1- diphenyl 2-picrylhyorazyl (DPPH) is a well-known radical and a trap (scavenger) for other radicals. Hyaluronidase (HAase) is an enzyme that depolymerizes the polysaccharide hyaluronic acid (HA) in the extracellular matrix of connective tissue. Lipoxygenase (LOX) enzyme was reported to convert the arachidonic, linoleic and other polyunsaturated fatty acid into biologically active metabolites involved in the inflammatory and immune responses. The purpose of the present study is to evaluate plant extracts as sources of natural antioxidants and to examine whether Achyranthes japonica having significant DPPH, HAase and LOX inhibitory activity. The inhibitory effect of HAase by A. japonica was assayed using a Morgan microplate assay. The antioxidant activity of the A. japonica extracts was measured on the basis of the scavenging activity of the stable 1, 1- diphenyl 2-picrylhyorazyl (DPPH) free radical. DPPH scavenging activity of matured roots of A. japonica was evaluated at 4.0 mg/ml was 87.8% and that of young roots was 86.2% at same concentration. The roots of A. japonica showed maximum inhibition of HAase activity (IC₅₀ = 27.7 μg/ml). The highest LOX inhibition was recorded in the root extract among three vegetative parts. Inhibition of HAase activity of roots may contribute towards the development of herbal medicines. Although percent inhibition of lipoxygenase by Achyranthes japonica for all young and matured groups for leaves, stems, and roots at different concentrations, there were not show a statistically significant difference (p<0.05).

• Journal of the Korean Society of Radiology
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• v.1 no.1
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• pp.11-16
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• 2007

In this study, we have performed contrast-detail analysis for an amorphous selenium(a-Se) based digital X-ray imaging system by using a contrast-detail phantom(CDRAD 2.0) to test its low contrast performance. The X-ray imaging system utilizes an 500-mm-thick a-Se semiconductor X-ray absorber coated over an amorphous silicon(a-Si) TFT(thin-film transistor) detector matrix with a $139mm{\times}139mm$ pixel size and a $46.7cm{\times}46.7cm$ active area. In the measurement of contrast-detail curves we first acquired X-ray images of the CDRAD 2.0 phantom at given test conditions(i.e., 40, 50, 60, 70, 80 kVp, and 16 mA.s), and then evaluated the contrast-detail characteristics of the imaging system from each phantom image by using an image quality factor called the image-quality-figure-inverse(IQFinv). The IQFinv values for the imaging system gradually improved with the photon fluence, indicating the improvement of image visibility: 24.4, 35.3, 39.2, 41.5, and 43.4 at photon fluences of $1.8{\times}105$, $5.9{\times}105$, $11.3{\times}105$, $19.4{\times}105$, and $29.4{\times}105$ photons/$mm^2$, respectively.

• Journal of the Korean Vacuum Society
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• v.22 no.1
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• pp.37-44
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• 2013

In order to investigate an influence of carrier trap by quantum dots (QDs) on the solar parameters, in this study, the $p^+-QD-n/n^+$ solar cells with InAs/GaAs QD active layers are fabricated, and their characteristics are investigated and compared with those of a GaAs matrix solar cell (MSC). Two different types of QD structures, the Stranski-Krastanow (SK) QD and the quasi-monolayer (QML) QD, have been introduced for the QD solar cells, and the parameters (open-circuit voltage ($V_{OC}$), short-cirucuit current ($I_{SC}$), fill factor (FF), conversion efficiency (CE)) are determined from the current-voltage characteristic curves under a standard solar illumination (AM1.5). In SK-QSC, while FF of 80.0% is similar to that of MSC (80.3%), $V_{OC}$ and $J_{SC}$ are reduced by 0.03 V and $2.6mA/cm^2$, respectively. CE is lowered by 2.6% as results of reduced $V_{OC}$ and $J_{SC}$, which is due to a carrier trap into QDs. Though another alternative structure of QML-QD to be expected to relieve the carrier trap have been firstly tried for QSC in this study, it shows negative results contrary to our expectations.

• Applied Microscopy
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• v.34 no.1
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• pp.1-11
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• 2004

The wound healing is very complex biological processing including inflammatory, reepithelialization and matrix construction. According to the biological systematic category, the ability of the healing is very different. Generally healing ability of the lower animal group has been known more excellent compared to its higher group. Therefore, lower animals have been used as the experimental model to explore the mechanism of the wound healing or repair. To verify histochemical characteristics of the wound healing, we have used skin of the frog (Bombina orientalis) as known common amphibian. At day 1, 10, and 16, the mucous substance was very actively synthesized and strong positive by PAS and Alcian blue (pH 2.5). Day 10 after wounding, margin of the wound was gradually strong positive by PTAH staining for detection of collagen synthesis. At 3 to 6 hour and day 23 to 27, we have found the cell division was active through the MG-P staining, in which the concentration and division of DNA in nucleus was green to deep blue color.

• Clinical and Experimental Reproductive Medicine
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• v.29 no.4
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• pp.323-335
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• 2002

Object: The present study was accomplished to obtain a gene expression profile of the luminal epithelium during embryo apposition in comparison of implantation (1M) and interimplantation (INTER) sites. Material and Method: The mouse uterine luminal epithelium from IM and INTER sites were sampled on day 4.5 (Day of vaginal plug = day 0.5) by Laser Captured Microdissection (LCM). RNA was extracted from LCM captured epithelium, amplified, labeled and hybridized to microarrays. Results from microarray hybridization were analyzed by Significance Analysis of Microarrays (SAM) method. Differential expression of some genes was confirmed by LCM followed by RT-PCR. Results: Comparison of IM and INTER sites by SAM identified 73 genes most highly ranked at IM, while 13 genes at the INTER sites, within the estimated false discovery rate (FDR) of 0.163. Among 73 genes at IM, 20 were EST/unknown function, and the remain 53 were categorized to the structural, cell cycle, gene/protein expression, immune reaction, invasion, metabolism, oxidative stress, and signal transduction. Of the 24 structural genes, 14 were related especially to extracellular matrix and tissue remodeling. Meanwhile, among 13 genes up-regulated at INTER, 8 genes were EST/unknown function, and the rest 5 were related to metabolism, signal transduction, and gene/protein expression. Among these 58 (53+5) genes with known functions, 13 genes (22.4%) were related with $Ca^{2+}$ for their function. Conclusions: Results of the present study suggest that 1) active tissue remodeling is occurring at the IM sites during embryo apposition, 2) the INTER sites are relatively quiescent than IM sites, and 3) the $Ca^{2+}$ may be a crucial for apposition. Search for human homologue of those genes expressed in the mouse luminal epithelium during apposition will help to understand the implantation process and/or implantation failure in humans.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.2
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• pp.105-121
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• 2011

The operation of tidal power facility may induce severe changes of water quality in Shihwa Lake. Current water quality data are quite important to water quality management policy of Shihwa Lake. Thus, the water quality data of Shihwa Lake and its adjacent sea in 2010 were presented to characterize the temporal and spatial changes of water parameters such as pH, SS, DO, COD, dissolved nutrients, chlorophyll-a, TN and TP. Highest levels of water quality parameters were observed near the Shihwa and Banweol industrial complexes and the levels of water quality parameters were on a decreasing trend to those near the water gate. It suggests that the horizontal distributions of water quality levels are mainly controlled by the supply of fresh water from streams and the inflow of outer seawater by operation of water gate. Although the higher concentrations of TN and TP were observed in the location being affected by Sorae port, the levels of water quality parameters in outer sea of Shihwa Lake were lower than those in Lake. In summer season, hypoxic condition was well developed in bottom water by strong stratification and active decomposition of organic matter. Thus, the vertical distributions of dissolved nutrient, TN and TP concentrations showed the concentrations to be higher in bottom seawater than those in surface seawater whereas the vertical distributions of chlorophyll-a, COD and POC concentrations showed the concentrations to be higher in surface seawater than those in bottom water. Results of Pearson's correlation matrix for surface seawater demonstrated that salinity showed negatively good correlation with not only dissolved nutrients except for ammonium but chlorophyll-a, COD and POC This result indicates that the supply of dissolved nutrients through several streams might significantly affect phytoplankton bloom and increase of COD concentration in surface seawater.