• Journal of Life Science
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• v.25 no.8
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• pp.849-860
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• 2015

The anti-cancer activities of Rhus verniciflua Stokes (GC), Ulmus davidiana var. japonica Nakai (UGP) and arsenium sublimatum (SS) extracts, which have been used Oriental medicine therapy for various diseases, were investigated. The treatment of GC, UGP and SS alone, and combined treatment with GC, UGP and SS did not affect the cell viability in the mouse normal cell lines (RAW 264.7 macrophages and C2C12 myoblasts). However, co-treatment with GC, UGP and SS markedly induces apoptosis in human gastric cancer AGS cells, but not in other various cancer cell lines (human lung cancer A549, colon cancer HCT116, liver cancer Hep3B and bladder T24 cells) as evidenced by formation of apoptotic bodies, chromatin condensation, and accumulation of annexin-V positive cells. Co-treatment with GC, UGP and SS effectively induced the expression levels of Fas and Fas ligand, and inhibited the levels IAP family proteins such as XIAP, cIAP-1 and survivin, and anti-apoptotic Bcl-xL proteins compared with treatment with either agent alone. Combined treatment also significantly induced the loss of mitochondrial membrane potential, which was associated with the activation of caspases (-3, -8, and -9) and degradation of poly (ADP-ribose) polymerase. However, the cytotoxic effects induced by co-treatment with GC, UGP and SS were significantly attenuated by pan-caspases inhibitor, z-VAD-fmk, indicating an important role for caspases. These results indicated that the caspases were key regulators of apoptosis in response to co-treatment of GC, UGP and SS in human gastric cancer AGS cells and further studies will be needed to identify the active compounds.

• Korean journal of applied entomology
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• v.55 no.2
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• pp.81-89
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• 2016

Double-stranded RNA (dsRNA) has been applied to control insect pests by its suppressive activity against specific target genes. Integrin is a heterodimer (${\alpha}$ and ${\beta}$) transmembrane protein and plays a critical role in cell-to-cell or cell-to-extracellular matrix interactions in eukaryotes. Suppression of ${\beta}$ subunit integrin gene expression by its specific dsRNA (= dsINT) induces significant mortality against target insects. Furthermore, a recombinant bacterium expressing dsINT is potent to kill target insects. However, it is necessary to develop a formulation technique of the dsRNA-expressing bacteria to apply the bacterial insecticide against field populations. This study formulated the recombinant bacteria by freeze-drying and tested its control efficacy against target insects. The formulation maintained significant insecticidal activity against last instar larvae of Spodoptera exigua. While a commercial Bacillus thuringiensis (Bt) insecticide exhibited only about 60% insecticidal activity against S. exigua last instar, an addition of the dsINT-expressing bacterial formulation significantly enhanced the Bt insecticidal activity. The dsINT-expressing bacterial formulation exhibited relative selectivity to target insects depending on sequence similarity. These results indicate that a freeze-dried form of dsRNA-expressing bacteria keeps its insecticidal activity.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.674-683
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• 2010

The current study was performed to examine the agricultural suitability of the cultivated upland nearby abandoned mining areas in Korea using three different scientific risk assessment models of Korea, USA and UK. For this, three mining sites DM, MG and KS were selected among 687 abandoned mines through preliminary risk assessment. A wide range of parameters were obtained through analysis of both soil and crop samples from the selected areas for heavy metal concentration and questionnaires to the communities along with the selected mining sites. Heavy metal concentration in soil samples was lower than the values previously reported by the Ministry of Environment (ME, 2002). However, both As and Cd concentration in the soil samples exceeded the concern level for agricultural area of the Soil Environment Conservation Act. Judging from the contaminant criteria for the crops, only Zn level in pepper, soybean and corn from the mining area DM exceeded the criteria whereas As, Cd, $Cr^{6+}$, Cu, Hg, Ni, Pb did not exceed the criteria. It was demonstrated that there would be human health risk by Pb accumulated in crops from both mining areas MG and KS when estimated by the risk assessment models of Korea and USA. Against it, results of the risk assessment model of UK showed human health risk by Pb in the crops from all study areas.

• Journal of Korean Neurosurgical Society
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• v.29 no.6
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• pp.731-737
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• 2000

Objective : Growth factor receptors on the tumor cells are known to be expressed highly allowing the tumor cells to bind growth factors to stimulate cellular division. Immunotoxin therapy is one of the novel approaches to the primary malignant brain tumor, and expression of cell-surface receptor is essential for the immunotoxin to have specific anti-tumor activity. Despite promising cytotoxic activity of immunotoxin, tumor responses are not curative on clinical trials, and additional studies are needed regarding various factors influencing the efficacy of the immunotoxin. The purpose of this study is to detect the expression of various growth factor receptors on brain tumor cell lines which are going to be used in these studies. Materials and Methods : The authors detected transferrin receptor(TR), insulin-like growth factor-1 receptor(IGF-1R), and interleukin-4 receptor(IL-4R) on medulloblastoma cell line(Daoy) and glioblastoma cell lines(U373 MG and T98 G) by flow cytometric analysis. Results : TR was expressed on Daoy, U373 MG, and T98 G. IGF-1R was expressed on Daoy and U373 MG, but not on T98 G. IL-4R was expressed on all cell lines tested. Conclusion : The transferrin and interleukin-4 receptors might be good targets for immunotoxin therapy. The results should be considered in additional in vitro and in vivo studies regarding immunotoxin and in establishing the proper treatment model of the immunotoxin therapy including selection of the adequate immunotoxin.

• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.114-126
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• 2020

Bloom-forming toxic cyanobacteria Microcystis spp. are common in the summer season in temperate freshwater ecosystems. Often, it leads to the degradation of water quality and affects the quality of drinking water. In a previous study, NQ (naphthoquinone) compounds were shown to be effective, selective, and ecologically safe algicides for Microcystis spp. blooms. To analyze the superiority of developed NQ derivatives, we conducted a microcosm experiment using clay, which is frequently used in South Korea. Similar to previous studies, the NQ 40 and NQ 2-0 compounds showed high algicidal activities of 99.9% and 99.6%, respectively, on Microcystis spp. at low concentrations (≥1 μM) and enhanced phytoplankton species diversity. However, when treated with clay, a temporary algicidal effect was seen at the beginning of the experiment that gradually increased at the end. In addition, treatment with the NQ compounds did not affect either the abiotic or biological factors, and similar trends were observed with the control. These results showed that the NQ 2-0 compound was more effective, with no ecosystem disturbance, and more economical than the currently used clay. These results suggest that NQ 2-0 compound could be a selective, economically and ecologically safe algicide to mitigate harmful cyanobacterial blooms in the field.

• Journal of the Korean Electrochemical Society
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• v.17 no.3
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• pp.164-171
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• 2014

A highly sensitive and selective non-enzymatic glucose sensor has gained great attention because of simple signal transformation, low-cost, easily handling, and confirming the blood glucose as the representative technology. Until now, glucose sensor has been developed by the immobilization of glucose oxidase (GOx) on the surface of electrodes. However although GOx is quite stable compared with other enzymes, the enzyme-based biosensors are still impacted by various environment factors such as temperature, pH value, humidity, and toxic chemicals. Non-enzymatic sensor for direct detecting glucose is an attractive alternative device to overcome the above drawbacks of enzymatic sensor. Many efforts have been tried for the development of non-enzymatic sensors using various transition metals (Pt, Au, Cu, Ni, etc.), metal alloys (Pt-Pb, Pt-Au, Ni-Pd, etc.), metal oxides, carbon nanotubes and graphene. In this paper, we show that Ni-based nano-particles (NiNPs) exhibit remarkably catalyzing capability for glucose originating from the redox couple of $Ni(OH)_2/NiOOH$ on the surface of ITO electrode in alkaline medium. But, these non-enzymatic sensors are nonselective toward oxidizable species such as ascorbic acid the physiological fluid. So, the anionic polymer was coated on NiNPs electrode preventing the interferences. The oxidation of glucose was highly catalyzed by NiNPs. The catalytically anodic currents were linearly increased in proportion to the glucose concentration over the 0~6.15 mM range at 650 mV versus Ag/AgCl.

• Polymer(Korea)
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• v.36 no.5
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• pp.586-592
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• 2012

Iron oxides ($Fe_3O_4$) are metabolically secreted after endocytosed by cells, indicating no cytotoxicity. Therefore, they are widely used as a contrast agent before photographing of magnetic resonance imaging. In this study, iron oxide nanoparticles are synthesized by the co-precipitation method and subsequently immobilized with a homing peptide (AP), which specifically interacts with interleukin-4 receptor located on the membrane of endothelial and bladder cancer cells. The size of AP-immobilized iron oxide particle is about 39 nm. Intracellular uptake of the AP-immobilized iron oxide nanoparticles was investigated using bladder cancer cells and fibroblasts as the control. As the result, the nanoparticles are specificially uptaken by bladder cancer cells. However, the nanoparticles are not specificially uptaken by fibroblast. It could be said that the AP-immobilized iron oxide nanoparticles have a potential to be used as a contrast agent for early diagnosis of cancer.

• Proceedings of the Ginseng society Conference
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• 1988.08a
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• pp.28-32
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• 1988

Recently, we isolated a toxic substance named 'toxohormone-L' from ascites fluid of patients with various malignant tumors. The toxohormone-L stimulated lipolysis in rat adipocytes and induced anorexia in rats. Both the lipolytic and the anorexigenic actions of toxohormone-L were found to be inhibited by ginsenoside $Rb_2$ in Korean red ginseng. Isolated rat adipocytes are well known to possess opposite pathways of lipid metabolism: lipolysis and lipogenesis. Both of the metabolism respond to various biologically active substances such as epinephrine, ACTH and insulin. Epinephrine and ACTH stimulate lipolysis and insulin accelerates lipogenesis. Recently. Korean red ginseng powder was found to contain adenosine and an acidic substance which inhibited epinephrine-induced lipolysis and stimulated insulin-mediated lipogenesis from added glucose. The chemical structure of this acidic substance is determined to be pyro-glutamic acid (Pyro-Glu), Pyro-Glu exhibits selective modulations toward the opposite metabolic pathways in rat adipocyte; It inhibits the lipolysis but stimulates the lipogenesis. We call these substances (adenosine, Pyro-Glu) 'selective modulators' or 'insulin-like substances'. Based on these results, physiological significances of these substances in Korean red ginseng were discussed.

• Analytical Science and Technology
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• v.31 no.6
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• pp.225-231
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• 2018

Benzoic acid, methyl paraben, and butyl paraben are preservatives that have been used in pharmaceutical, cosmetic, and food products. However, as their toxicities for human have been reported, many nations and organizations including Korea have established a regulation limit for thier usage of these preservatives in food products. The present study developed the isotope dilution liquid chromatography mass spectrometry method for accurate determination of three target preseratives in soysauce. In this study, the isotope dilution liquid chromatography mass spectrometry method was developed for accurate determination of three target preservatives in soy sauce. LC separation was optimized considering the pKa of benzoic acid which is lower than those of methyl and butyl parabens. A C18 column was used with 5 mM ammonium acetate and methanol as mobile phases. Mass spectrometry was operated in negative mode and selected reaction monitoring mode (SRM). Soy sauce sample was cleaned-up with C18 SPE cartridge for removing matrix inferences and color material. Optimized conditions and the method were validated with soy sauce reference materials for the analysis of food preservatives from Health Science Authority in Singapore. The measured values of benzoic acid, methyl and butyl paraben agreed well with reference values within their uncertainties.

• Applied Chemistry for Engineering
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• v.33 no.2
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• pp.126-132
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• 2022

Alkaline fuel cells using liquid fuels such as hydrazine and ammonia are gaining great attention as a clean and renewable energy solution possibly owing to advantages such as excellent energy density, simple structure, compact size in fuel container, and ease of storage and transportation. However, common shortcomings including cathode flooding, fuel crossover, side yield reactions, and fuel security and toxicity are still challenging issues. Real time monitoring of fuel concentrations integrated into a fuel cell device can help improving fuel cell performance via predicting any loss of fuels used at a cathode for efficient energy production. There have been extensive research efforts made on developing real-time sensing platforms for hydrazine and ammonia. Among these, recent advancements in electrochemical sensors offering high sensitivity and selectivity, easy fabrication, and fast monitoring capability for analysis of hydrazine and ammonia concentrations will be introduced. In particular, research trend on the integration of metallic and metal oxide nanoparticles and also their hybrids with carbon-based nanomaterials into electrochemical sensing platforms for improvement in sensitivity and selectivity will be highlighted.