• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.4
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• pp.277-286
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• 2006

In the present study, I investigated the effects of N-methyl-D-aspartate (NMDA), arachidonic acid (AA), and Nitric Oxide Synthase Inhibitor (NOS-I), alone or in combination, on the viability of cultured primary normal human oral keratinocytes (NHOK). Specifically, we examined whether AA and NOS-I could protect primary NHOK from glutamate cytotoxicity. The purpose of this study was therefore the preliminary study for the examination of the interaction between these agents and NHOK in order to elucidate the mechanisms by which epithelial growth and regeneration are regulated. NHOK were obtained from gingival tissue of 20 individuals aged 20 to 29, and third passage (P3) cells were used for this study. Cell viability was measured by the MTT assay. NMDA and NNA, a calcium dependent NOS inhibitor, induced an initial increase in cell number, which subsequently decreased by the $7^{th}$ day. Low concentration of AA ($0.5\;{\mu}M$ & $1\;{\mu}M$) induced an increase in cell number while high concentrations of AA ($5\;{\mu}M$ & $10\;{\mu}M$) induced a decrease in cell number. The decrease in cell number induced by NMDA at the $7^{th}$ day was abolished by the addition of low concentrations of AA ($0.5\;{\mu}M$ & $1\;{\mu}M$) or NOS inhibitors. Low concentrations of AA ($0.5\;{\mu}M$ & $1\;{\mu}M$) or NOS inhibitors may protect the NHOK from NMDA induced cytotoxicity. These reactions might be related to the NMDA receptor in the cell and the change of the intracellular calcium ion concentration.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.197-197
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• 2016

Commercially pure titanium (CP Ti) and Ti-6Al-4V alloys have been widely used for biomedical applications. However, the use of the Ti-6Al-4V alloy in biomaterial is then a subject of controversy because aluminum ions and vanadium oxide have potential detrimental influence on the human body due to vanadium and aluminum. Hence, recent works showed that the synthesis of new Ti-based alloys for implant application involves more biocompatible metallic alloying element, such as, Nb, Hf, Zr and Mo. In particular, Nb and Hf are one of the most effective Ti ${\beta}-stabilizer$ and reducing the elastic modulus. Plasma electrolyte oxidation (PEO) is known as excellent method in the biocompatibility of biomaterial due to quickly coating time and controlled coating condition. The anodized oxide layer and diameter modulation of Ti alloys can be obtained function of improvement of cell adhesion. Manganese(Mn) plays very important roles in essential for normal growth and metabolism of skeletal tissue in vertebrates and can be detected as minor constituents in teeth and bone. Radio frequency(RF) magnetron sputtering in the various PVD methods has high deposition rates, high-purity films, extremely high adhesion of films, and excellent uniform layers for depositing a wide range of materials, including metals, alloys and ceramics like a hydroxyapatite. The aim of this study is to research the Mn coatings on the micro-pore formed Ti-29Nb-xHf alloys by RF-magnetron sputtering for dental applications. Ti-29Nb-xHf (x= 0, 3, 7 and 15wt%, mass fraction) alloys were prepared Ti-29Nb-xHf alloys of containing Hf up from 0 wt% to 15 wt% were melted by using a vacuum furnace. Ti-29Nb-xHf alloys were homogenized for 2 hr at $1050^{\circ}C$. Each alloy was anodized in solution containing typically 0.15 M calcium acetate monohydrate + 0.02 M calcium glycerophosphate at room temperature. A direct current power source was used for the process of anodization. Anodized alloys was prepared using 270V~300V anodization voltage at room. Mn coatings was produced by RF-magnetron sputtering system. RF power of 100W was applied to the target for 1h at room temperature. The microstructure, phase and composition of Mn coated oxide surface of Ti-29Nb-xHf alloys were examined by FE-SEM, EDS, and XRD.

• The Journal of Internal Korean Medicine
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• v.25 no.1
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• pp.16-27
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• 2004

In the traditional Chinese medicine, Drynariae Rhizoma (DR) has been reported as a good enhancer for bone healing. DR, a plant widely used in the traditional medicinal systems of Korea, has been reported to possess antiviral, antibacterial and anti-inflammatory activities. Modulation of immune response to alleviate disease has been of interest for a long time. Plant extracts have been widely investigated for possible immunomodulatory properties. Thus, I have evaluated the anticellular and immunomodulatory properties of ethanolic extract of DR. DR extract inhibited proliferation of mitogen (phytohaemagglutinin; PHA) and antigen (purified protein derivative; PPD)-stimulated human peripheral blood mononuclear cells (PBMCs). In addition, DR inhibited growth of several cell lines of mouse and human origin. It also inhibited production of nitric oxide (NO), interleukin-2 (IL-2) and tumor necrosis $factor-{\alpha}\;(TNF-{\alpha})$. Intracytoplasmic $interferon-{\gamma}\;(IFN-{\gamma})$ and expression of cell surface markers, CD16 and HLA-DR, on human PBMC, were not affected on treatment with DR but CD25 expression was down regulated. This study demonstrates the antiproliferative and immunosuppressive potential of ethanolic extract of DR in vitro.

• Korean Journal of Food Science and Technology
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• v.48 no.4
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• pp.378-383
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• 2016

The glasswort is an edible halophyte demonstrating various physiological effects including anti-inflammatory activity. In the present study, the effects of glasswort extracts on inflammatory events and interactions of THP-1 monocytes with intestinal epithelial cells were investigated. Five solvent fractions, including the ethylether fraction (Fr.E), were prepared from a 70% methanol extract of glasswort. THP-1 monocytes underwent differentiation by phorbol 12-myristate 13-acetate treatment and were then activated by lipopolysaccharide (LPS), which induced cyclooxygenase (COX)-2 expression. None of the glasswort fractions tested alone induced COX-2 in differentiated THP-1 cells. Fr.E, however, enhanced LPS-induced COX-2 expression in differentiated THP-1 cells. Culture media of THP-1 cells treated with each fraction stimulated the growth of normal intestinal INT-407 cells more prominently than that of HT-29 colon cancer cells. COX-2 expression in HT-29 cells was inhibited when the cells were exposed to the THP-1 culture medium treated with Fr.E. Thus, glasswort could modulate the interaction between immune cells and intestinal cells.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.2
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• pp.9-17
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• 2010

Recently, there has been much interest in orthogonal frequency division multiplexing (OFDM) for next generation wireless wideband communication systems. OFDM is a special case of multicarrier transmission, where a single data stream is transmitted over a number of lower-rate subcarriers. One of the main reasons to use OFDM is to increase robustness against frequency-selective fading or narrowband interference. However, in the radio systems it is also important to distortion introduced by high power amplifiers (HPA's) such as solid state power amplifier (SSPA) considered in this paper. Since the signal amplitude of the OFDM system is Rayleigh-distributed, the performance of the OFDM system is significantly degraded by the nonlinearity of the HPA in the OFDM transmitter. In this paper, we propose a canonical piecewise-linear (PWL) model based digital predistorter to prevent signal distortion and spectral re-growth due to the high peak-to-average power ratio (PAPR) of OFDM signal and the nonlinearity of HPA's. Computer simulation on an OFDM system under additive white Gaussian noise (AWGN) channels with QPSK, 16-QAM and 64-QAM modulation schemes and modulator/demodulator implemented with 1024-point FFT/IFFT, demonstrate that the proposed predistorter achieves significant performance improvement by effectively compensating for the nonlinearity introduced by the SSPA.

• Radiation Oncology Journal
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• v.34 no.3
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• pp.223-229
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• 2016

Purpose: This study is to investigate the effect of captopril when combined with irradiation. Materials and Methods: 4T1 (mouse mammary carcinoma) cells were injected in the right hind leg of Balb/c mice. Mice were randomized to four groups; control (group 1), captopril-treated (group 2), irradiated (group 3), irradiated and captopril-treated concurrently (group 4). Captopril was administered by intraperitoneal injection (10 mg/kg) daily and irradiation was delivered on the tumor-bearing leg for 15 Gy in 3 fractions. Surface markers of splenic neutrophils (G-MDSCs) and intratumoral neutrophils (tumor-associated neutrophils [TANs]) were assessed using flow cytometry and expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor 1 alpha ($HIF-1{\alpha}$) of tumor was evaluated by immunohistochemical (IHC) staining. Results: The mean tumor volumes (${\pm}$standard error) at the 15th day after randomization were $1,382.0({\pm}201.2)mm^3$ (group 1), $559.9({\pm}67.8)mm^3$ (group 3), and $370.5({\pm}48.1)mm^3$ (group 4), respectively. For G-MDSCs, irradiation reversed decreased expression of CD101 from tumor-bearing mice, and additional increase of CD101 expression was induced by captopril administration. Similar tendency was observed in TANs. The expression of tumor-necrosis factor-associated molecules, CD120 and CD137, are increased by irradiation in both G-MDSCs and TANs. Further increment was observed by captopril except CD120 in TANs. For IHC staining, VEGF and $HIF-1{\alpha}$ positivity in tumor cells were decreased when treated with captopril. Conclusion: Captopril is suggested to have additional effect when combined to irradiation in a murine tumor model by modulation of MDSCs and angiogenesis.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.5915-5920
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• 2013

Aim: Although aberrant miRNA expression has been documented, altered miR-101 expression in cervical cancer and its carcinogenic effects and mechanisms remain unexplored. The aim of our study was to investigate the role of miR-101 alteration in cervical carcinogenesis. Methods: Expression of miR-101 was examined by quantitative real-time reverse transcriptase PCR (qRT-PCR) in Hela cells. After modulating miR-101 expression using miR-101 mimics, cell growth, apoptosis and proliferation, and migration were tested separately by MTT or flow cytometry and cell wound healing assay and protein expression was detected by qRT-PCR. The expression of COX-2 in Hela cell was also examined by immunohistochemical staining and the correlation with miR-101 expression was analysed. Results: The miR-101 demonstrated significantly low expression in Hela cell. When we transfected miR-101 mimics into Hela cells, the modulation of miR-101 expression remarkably influenced cell proliferation, cycling and apoptosis: 1) The expression of microRNA-101 tended to increase after transfection; 2) Overexpression of miR-101 was able to promote cell apoptosis, the apoptosis rate being markedly higher (97.6%) than that seen pre-transfection (12.2%) (P<0.05); 3) The miR-101 negatively regulates cell migration and invasion, scratch results being lower ($42.7um{\pm}2um$) than that observed pre-transfection ($181.4um{\pm}2um$); 4) miRNA-101 inhibits the proliferation of Hela cells as well as the level of COX-2 protein, which was negatively correlated with miR-101 expression. Conclusions: Overexpression of miR-101 has obvious inhibitory effects on cell proliferation, migration and invasion. Thus reduced miR-101 expression could participate in the development of cervical cancer at least partly through loss of inhibition of target gene COX-2, which probably occurs in a relative late phase of carcinogenesis. Our data suggest an important role of miR-101 in the molecular etiology of cancer and indicate potential application of miR-101 in cancer therapy.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.7
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• pp.907-913
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• 2012

Piceatannol (trans-3,4,3',5'-tetrahydroxystilbene) is a polyphenol detected in grapes, rhubarb, and sugarcane. Although recent experimental data revealed that this compound is known to exhibit immunosuppressive and antitumorigenic activities in several cell lines, the molecular mechanisms underlying anticancer activity are poorly understood. In the present study, we investigated possible further mechanisms by which piceatannol exerts its anti-proliferative action in cultured human gastric cancer AGS cells. Piceatannol treatment resulted in the inhibition of growth and G1 arrest of the cell cycle in a concentration-dependent manner, as determined by MTT assay and flow cytometry analysis. The induction of G1 arrest by piceatannol was associated with the modulation of cyclin-dependent kinases (Cdks) and cyclins, up-regulation of the expression of Cdk inhibitor p21 (WAF1/CIP1) in both transcriptional and translational levels, and the inhibition of phosphorylation of retinoblastoma proteins and E2F1 expression. In addition, piceatannol treatment caused a progressive decrease in the expression levels of cyclooxygenase (COX)-2 without significant changes in the levels of COX-1, which was correlated with a decrease in prostaglandin $E_2$ synthesis.

• Biomolecules & Therapeutics
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• v.28 no.4
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• pp.320-327
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• 2020

In current study, we aimed to investigate whether the gentiopicroside (GPS) derived from Gentiana manshurica Kitagawa could block the progression of alcoholic hepatic steatosis to fibrosis induced by chronic ethanol intake. C57BL/6 mice were fed an ethanol-containing Lieber-DeCarli diet for 4 weeks. LX-2 human hepatic stellate cells were treated with GPS 1 h prior to transforming growth factor-β (TGF-β) stimulation, and murine hepatocyte AML12 cells were pretreated by GPS 1 h prior to ethanol treatment. GPS inhibited the expression of type I collagen (collagen I), α-smooth muscle actin (α-SMA) and tissue inhibitor of metal protease 1 in ethanol-fed mouse livers with mild fibrosis. In addition, the imbalanced lipid metabolism induced by chronic ethanol-feeding was ameliorated by GPS pretreatment, characterized by the modulation of lipid accumulation. Consistently, GPS inhibited the expression of collagen I and α-SMA in LX-2 cells stimulated by TGF-β. Inhibition of lipid synthesis and promotion of oxidation by GPS were also confirmed in ethanol-treated AML12 cells. GPS could prevent hepatic steatosis advancing to the inception of a mild fibrosis caused by chronic alcohol exposure, suggesting GPS might be a promising therapy for targeting the early stage of alcoholic liver disease.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.3
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• pp.174-182
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• 2006

This study was to clarify the effects of forest stand changes on hydrological components of evapotranspiration and discharge. The forest-hydrological experimental stations in Gwangneung and Yangju, Gyeonggido near metropolitan Seoul have been operated by the Korea Forest Research Institute since 1979 to clarify the effects of forest types and practices on the water resources and nutrient cycling and soil loss. The hydrological regime of the forested catchments may change as forests develop. The ranges of change may be different depending on forest types. Evapotranspiration can be estimated to 679mm, 580mm and 368mm in planted young coniferous (PYC), natural old-growth deciduous (NOD) and rehabilitated young mixed (RYM), respectively. The slope of the discharge-duration curve shows the capacity of discharge control in a specific catchment. The slope tended to be steeper in RYM than NOD, the better forest condition. The slope in RYM became more gentle as the forest stand developed. Forests can modulate peak flows through interception, evapotranspiration and soil storage opportunity. PYC and RYM showed 100 and 50mm of threshold rainfall for modulating peak flows, respectively. The deciduous forest did not represent sudden changes of peak flow rates to rainfall, even 200 mm rainfall Forest development in PYC may play an important role in modulation of peak flows because peak flow rates reduced after 10 years.