• Applied Chemistry for Engineering
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• v.23 no.5
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• pp.474-479
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• 2012

Possibility of the selective removal of $Ca^{2+}$ ions from a mixed solution of $Na^{+}$ and $Ca^{2+}$ ions using membrane capacitive deionization (MCDI) was investigated. Adsorption equilibrium experiments were conducted to determine the selectivity of the CMX cation-exchange membrane toward $Ca^{2+}$ ions. In addition, desalination experiments for a mixed solution (5 meq/L NaCl + 2 meq/L $CaCl_{2}$) were performed using an MCDI cell. The adsorption equilibrium of CMX membrane showed that the equivalent fraction of $Ca^{2+}$ ions in the solution and the CMX membrane were 28.6 and 87.2%, respectively, which indicates the CMX membrane's high selectivity toward $Ca^{2+}$ ions. Desalination experiments were performed by applying a constant current to the MCDI cell until the cell potential reached 1.0 V. The amount of ions adsorbed did not significantly change as the applied current was changed. However, the equivalent fractions of $Ca^{2+}$ ions among the adsorbed ions were inversely proportional to the applied currents: 81.4, 78.4, 77.0, and 74.5% at 200, 300, 500, and $700\;A/m^{2}$ of applied current density, respectively. This result is attributed to the increased fraction of $Ca^{2+}$ ions adsorbed by the CMX membrane at lower applied current densities.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.261-261
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• 2006

Membranes are a central feature of all biological systems and their ability to control many cellular processes is critically important. As a result, a better understanding of how molecules bind to biological membranes is an active area of research. In this report, the interaction between our biomimetic structures and different biological membranes is reported using both model vesicle and in vitro bacterial cell experiments. These results show that lipid composition is more important for selectivity than overall net charge. An effort is made to connect model vesicle studies with in vitro data and naturally occurring lipid compositions.

• Toxicological Research
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• v.19 no.1
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• pp.45-50
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• 2003

The purpose of this study was to determine the role of substituted groups in phenolic compounds to develop an anticancer agent having strong cytotoxicity against cancer cells but weak against normal cells. The phenolic compounds used in this study were gallic acid and ferulic acid with hydroxyl and carboxyl groups, syringic acid with hydroxyl, carboxyl and methoxy groups, and pyre-gallol with hydroxyl groups. Cytotoxicities of these compounds were evaluated by MTT assay for cell viability and XTT assay for cell adhesion activity in normal human skin fibroblast (Detroit 551) and human skin melanoma (SK-MEL-3) cells. Syringic acid, gallic acid and ferulic acid decreased the cell viability and cell adhesion activity in SK-MEL-3 cells but not in Detroit 551 cells while pyrogallol decreased in both cells. The susceptibility of cell viability based on the $IC_{50}$ values of MTT assay in Detroit 551 cells was in the following order: pyrogallol > gallic acid > ferulic acid > syringic acid, while it was in SK-MEL-3 cells: Syringic acid > progallol > ferulic acid > gallic acid. These results suggest that carboxyl and methoxy groups of these compounds play an important role in selectivity of cytotoxicity in normal and cancer cells.

• Korean Journal of Medicinal Crop Science
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• v.12 no.4
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• pp.304-308
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• 2004

Immune enhancing activities of water and ethanol extracts of Hypericum perforatum L. (HP) were examined. HP extracts inhibited the growth of human hepatocarcinoma, human gastric cancer cell and human breast cancer cells in concentration-dependent mammers over a concentration range of $0.05{\sim}1.0\;mg/ml$, showing inhibiton of more than 80% with the concentration of 1.0 mg/ml. However, HP the same concentration. Overall selectivity of the extracts on the three human cancer lines was over 3.5, which is higher than those from the conventional herbs. The growth of human immune B and T cells was enhanced up to 1.4 to 2.0 folds by the addition of the extracts for 4 days, compared to controls. Ethanol extracts of HP after 6 days incubation increased the secretions of tumor necrosis factor-alpha $(TNF-{\alpha})$ from T cells and interleukin-6 (IL-6) from B cells to 6.7 pg/cell and 6.8 pg/cell, respectively. These results suggest that HP has a potent immune enhancing effect.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.1
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• pp.40-46
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• 2017

We reviewed the electrical properties of SOFC anode manufactured using spherical Ni and nano YSZ powder. When core-shell is fabricated by using submicron Ni as core and nano-sized YSZ as shell for SOFC anode, the electrical conductivity of the $0.2{\mu}m$ Ni-YSZ core-shell was 3 times higher than that of $1.0{\mu}m$ NiO or $1.0{\mu}m$ Ni-YSZ. Hydrogen selectivity was similar at $800^{\circ}C$, but hydrogen selectivity and methane conversion rate under $750^{\circ}C$ was 10~25% higher, Power density was more than 2 times, ASR was about 1/3, when exposed to $H_2$ atmosphere at $750^{\circ}C$ for a long time, Ni particles did not have any growth or cut off conduction path.

• Transactions of the Korean hydrogen and new energy society
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• v.14 no.2
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• pp.155-170
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• 2003

$Cu-Ce/{\gamma}-Al_2O_3$ based catalysts were prepared and tested for selective oxidation of CO in a $H_2$-rich stream(1% CO, 1% $O_2$, 60% $H_2$, $N_2$ as balance). The effects of Cu loading and weight ratio(=Cu/(Cu+Ce)) upon both activity and selectivity were investigated upon the change in temperatures, It was also examined how the activity and selectivity of catalysts were varied with the presence of $CO_2$ and $H_2O$ in the reactant feed. Among the various Cu-Ce catalysts with different catalytic metal composition, Cu-Ce(4 : 16 wf%) /${\gamma}-Al_2O_3$ catalyst showed the highest activity(>$T_{99}$) and selectivities(50-80%) under wide range of temperatures($175-220^{\circ}C$). However, in the Cu-Ce(4 : 16 wt%)/ ${\gamma}-Al_2O_3$, the presence of $CO_2$ and $H_2O$ in the reactant feed decreased the activity and the maximum activity(>$T_{99}$) in terms of reaction temperature moved by about $25^{\circ}C$ toward higher temperature, the $T_{>99}$ window was seen between $210-230^{\circ}C$ (selectivity 50-75%). From $CO_2-/H_2O-TPD$, it can be concluded that the main cause for the decrease in catalytic activity may be attributed to the blockage of the active sites by competitive adsorption of water vapor and $CO_2$ with the reactant at low temperatures.

• Korean Journal of Pharmacognosy
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• v.30 no.1
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• pp.34-39
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• 1999

To search for less toxic antiherpetic agents, the inhibitory effects of twelve kinds of flavonoids including chrysin, quercetin, quercitrin, rutin, fisetin, gossypin, kaempferol, morin, naringenin, naringin, hesperetin and hesperidin on the plaque formation of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in Vero cells were examined by plaque reduction assay in vitro. Some flavonoids tested in this study showed potent antiherpetic activity, reducing intracellular replication of herpes simplex viruses when Vero cell monolayers were infected and subsequently cultured in medium containing flavonoids. Naringenin showed the most potent antiviral activity against HSV-1 with selectivity index (SI) of 19.1 and hesperetin showed the most potent antiviral activity against HSV-2 with SI of 9.8. These results suggest that some flavonoids may be a potential therapeutic agent for the treatment and prevention of herpes simplex virus infections.

• Journal of Biosystems Engineering
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• v.39 no.2
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• pp.111-114
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• 2014

Purpose: This review aims to introduce aptamers and the methods of its development to improve the sensitivity and selectivity to target bacteria. In this review, we have highlighted current developments and directions in the pathogen detection based on aptamers. Background: Aptamers, the specific nucleic acid sequences, can bind to targets with high affinity and specificity. Some of researches on the use of aptamers for the detection of pathogen have been reported in recent years. Aptamers have more applicability than antibodies for the development of pathogen detection using biosensor; such as easy to synthesis and labeling, lack of immunogenicity, and a low cost of production. However, only few reports on the development and use of aptamers for the detection of pathogen have been published. Review: Aptamers specific to pathogen are obtained by whole-cell systematic evolution of ligands by exponential enrichment (SELEX) process. SELEX process is composed of screening random oligonucleotide bound with target cells, multiple separation and amplification of nucleic acids, final identification of the best sequences. For improving those affinity and selectivity to target bacteria, optimization of multiple separating process to remove unbounded oligonucleotides from aptamer candidates and sorting process by flow cytometry are required.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.218-221
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• 2009

Solid oxide fuel cells (SOFCs), as high-temperature fuel cells, have various advantages. In some merits of SOFCs, high temperature operation can lead to the capability for internal reforming, providing fuel flexibility. SOFCs can directly use CH4 and CO as fuels with sufficient steam feeds. However, hydrocarbons heavier than CH4, such as ethylene, ethane, and propane, induce carbon deposition on the Ni-based anodes of SOFCs. In the case of the ethylene steam reforming reaction on a Ni-based catalyst, the rate of carbon deposition is faster than among other hydrocarbons, even aromatics. In the reformates of heavy hydrocarbons (diesel, gasoline, kerosene and JP-8), the concentration of ethylene is usually higher than other low hydrocarbons such as methane, propane and butane. It is importatnt that ethylene in the reformate is removed for stlable operation of SOFCs. A new methodology, termed post-reforming was introduced for removing low hydrocarbons from the reformate gas stream. In this work, activity tests of some post-reforming catalysts, such as CGO-Ru, CGO-Ni, and CGO-Pt, are investigated. CGO-Pt catalyst is not good for removing ethylene due to low conversion of ethylene and low selectivity of ethylene dehydrogenation. The other hand, CGO-Ru and CGO-Ni catalysts show good ethylene conversion, and CGO-Ni catalyst shows the best reaction selectivity of ethylene dehydrogenation.

• Korean Journal of Veterinary Service
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• v.37 no.2
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• pp.101-104
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• 2014

Toxoplasmosis is a parasitic disease caused by Toxoplasma gondii, with very few therapeutic treatment options. The choices for treatment are pyrimethamine and sulfadiazine, however their utility is limited because of drug toxicity and serious side effects. In this study, ethanol extracts of 13 traditional medicines used to treat Toxoplasma gondii were tested in vitro for their anti-Toxoplasma gondii cytotoxicity. The median effective concentration ($EC_{50}$) values for the herbal extracts ranged from 173 mg/mL to 1995.35 mg/mL. In HeLa cell, the selectivity of Alpinia oxyphylla (2.75), Mucunae Caulis (2.96), Dictamnus dasycarpus (7.52) which was higher than sulfadiazine (2.08). This indicates that Alpinia oxyphylla, Mucunae Caulis, Dictamnus dasycarpus extracts may be sources of new anti-Toxoplasma gondii compounds.