• Bulletin of the Korean Chemical Society
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• v.10 no.1
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• pp.5-8
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• 1989

Conventional ceramic method has been used to prepare the green phase, $Y_2BaCuO_5$, commonly observed in 90-K superconductor $YBa_2Cu_3O_P{7-{\delta}}$as an impurity phase. The powder X-ray diffraction analysis indicates that $Y_2BaCuO_5$ has an orthorhombic symmetry with lattice parameter of a = 12.2 $\AA$, b = 5.61 $\AA$, and c = 7.14 $\AA.$ The average g-value 2.13 observed in ESR spectrum is attributable to Cu2+ stabilized in $C_{4v}$ field. From the magnetic susceptibility ($\mu$eff = 2.29 BM) and the ESR measurements, it is confirmed that Cu(II) $3d^9$ electrons in $Y_2BaCuO_5$ are localized and can be characterized by Curie-Weiss behavior. Optical reflectance spectrum shows a broad absorption peak around 680 nm due to dxy ${\rightarrow}$ $dx^2-y^2$ eletronic transition.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.1
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• pp.24-30
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• 2003

The preparation of $PbTiO_3$ powder was carried out using the oxide starting material by hydrothermal method. The powder of a crystalline phase with perovskite structure was synthesized. The optimum conditions for the preparation of powder were as follows; hydrothermal solvent; 8M-KOH or 8M-NaOH, reaction temperature; 250~$270^{\circ}C$, run time; 10 h. The ,shape of synthesized powders were well developed crystalline faces with specific surface area of about 2.3 $\textrm m^2$/g in KOH solution and about 5.0 $\textrm m^2$/g in NaOH solution. The cell parameters of powder were a = 3.90$\AA$, c = 4.14 $\AA$ and cell volume was 57.30 $\AA^3$. The cell ratio (c/a) of powder was the same as the theoretical ratio with c/a = 1.06 and the phase transition temperature(Tc) of the powders was about $470^{\circ}C$.

• Environmental Mutagens and Carcinogens
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• v.11 no.2
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• pp.107-117
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• 1991

The effect of 3-aminobenzamide (3AB), an inhibitor of poly (ADP-ribose) polymerase, on ethyl methanesulfonate (EMS)-or bleomycin (BLM)-induced DNA repair synthesis and chromosome aberrations was examined during the cell cycle of Chinese hamster ovary (CHO)-K$_1$ cells. The synchronized cells were obtained by using thymidine double block method and mitotic selection method. Three assays were employed in this study: unscheduled DNA synthesis, alkaline elution and chromosome aberrations. 3AB alone did not induce DNA repair and chromosome aberrations in all phases. The post-treatment with 3AB inhibited DNA repair synthesis induced by EMS or BLM in G$_2$ phase, whereas 3AB did not affect chromosome aberrations induced by EMS or BLM in all phases. These results suggest that 3AB aggravates the cell cycle disturbance which occur after DNA damage, and leads to an accumulation of cells at G$_2$ phase, and inhibits DNA repair synthesis, while the effect 3AB on chromosome aberrations may need reevaluated.

• International Journal of Oral Biology
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• v.36 no.3
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• pp.143-148
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• 2011

The present study investigated the role of peripheral P2X receptors in inflammatory pain transmission in the orofacial area in rats. Experiments were carried out on male Sprague-Dawley rats weighing 220 to 280 g. Formalin (5%, 50 ${\mu}L$) and complete Freund's adjuvant (CFA, 25 ${\mu}L$) was applied subcutaneously to the vibrissa pad to produce inflammatory pain. TNP-ATP, a $P2X_{2,2/3,4}$ receptor antagonist, or OX-ATP, a $P2X_7$ receptor antagonist, was then injected subcutaneously at 20 minutes prior to formalin injection. One of the antagonists was administered subcutaneously at three days after CFA injection. The subcutaneous injection of formalin produced a biphasic nociceptive behavioral response. Subcutaneous pretreatment with TNP-ATP (80, 160 or 240 ${\mu}g$) significantly suppressed the number of scratches in the second phase produced by formalin injection. The subcutaneous injection of 50 ${\mu}g$ of OX-ATP also produced significant antinociceptive effects in the second phase. Subcutaneous injections of CFA produced increases in mechanical and thermal hypersensitivity. Both TNP-ATP (480 ${\mu}g$) and OX-ATP (100 ${\mu}g$) produced an attenuation of mechanical hypersensitivity. However, no change was observed in thermal hypersensitivity after the injection of either chemical. These results suggest that the blockade of peripheral P2X receptors is a potential therapeutic approach to the onset of inflammatory pain in the orofacial area.

• Polymer(Korea)
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• v.35 no.2
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• pp.130-135
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• 2011

Along with the fast development of electronics, the demands of portable electronics and wireless sensors are growing rapidly. The need for self-powering materials capable of powering the electrical devices attached to them is increasing, The piezoelectric effect of polyvinylidene fluoride (PVDF) can be used for this purpose. PVDF has a special crystal structure consisting of a ${\beta}$-phase that can produce piezoelectricity. In this paper, multilayer PVDF films were fabricated to increase the ${\beta}$-phase content. A solution of 10% concentration N;N-dimethylacetamide (DMAc) in PVDF (PVDF/DMAc) was used to fabricate the films via spin coating technique with the following optimum process parameters: a spin rate of 850 rpm, spin time of 60 s, drying temperature of $60^{\circ}C$, and drying time of 30 min, Compared with single-layer PVDF films, the multilayer films exhibited higher ${\beta}$-phase content. The ${\beta}$-phase content of the films increased gradually with increasing number of layers until 4, Maximum ratio of ${\beta}$-phase content was 7.72.

• Food Science and Biotechnology
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• v.15 no.5
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• pp.778-780
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• 2006

High performance liquid chromatography (HPLC) was used for the analysis of the lignans eleutheroside B and eleutheroside E in the fruits of Acanthopanax species. A reverse-phase system using a gradient of $H_2O$ and acetonitrile as the mobile phase was developed and detection was at 210 nm. The analysis was successfully carried out within 20 min. The content of eleutheroside B and eleutheroside E in Acanthopanax species was measured in the fruits of A. senticosus (0.58 and $1.66\;{\mu}g/mg$, respectively), A. sessiliflorus (1.15 and $8.49\;{\mu}g/mg$, respectively), A. koreanum (2.16 and $1.80\;{\mu}g/mg$, respectively), and A. divaricatus (1.06 and $7.08\;{\mu}g/mg$, respectively).

• Analytical Science and Technology
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• v.23 no.1
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• pp.54-59
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• 2010

The simultaneous analysis of parabens in cosmetic samples was carried out by LC/MS. The cosmetic samples are directly dissolved in methanol and filterated using $0.45\;{\mu}m$ filter. The methanol-water was used for the mobile phase of gradient conditions. An Extend $C_{18}$ reverse-phase column and the selected ion monitoring (SIM) mode were applied. The analysis results of LC/MS showed good linearity with correlation coefficient of $r^2$=0.9993 in the range of 0.05 to $10\;{\mu}g$/mL and detection limit of $0.01\;{\mu}g$/mL.

• Journal of the Korean Applied Science and Technology
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• v.30 no.4
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• pp.664-671
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• 2013

Determination of xanthan gum as watersoluble-polymer in commercial cosmetic samples was carried out by High Perfomance Liquid Chromatography(HPLC). An $C_{18}$ reversed-phase column and the selected ELSD detector was applied. The 25mM ammonium acetate/acetonitrile was used for the mobile phase of gradient conditions. The analysis results of HPLC showed good linearity with correlation coefficient of $r^2=0.9993$ in the rage of $50.3{\sim}604.1{\mu}g/ml$ and detection limit of $12.0{\mu}g/ml$.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.321-324
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• 2002

In situ recovery of recombinant human granulocyte-macrophage colony stimulating factor (hGM-CSF) was performed in transgenic Nicotiana tabacum cell suspension cultures. Aqueous two-phase systems (ATPS) were used to utilize its biocompatibility. Transgenic plant cells could be grown up to 15.7 g/L in normal medium and 18.6 g/L in ATPS composed of 6% (w/w) polyethylene glycol (PEG) 20,000 and 10% (w/w) dextran 2,000,000. It was proved that the A TPS was not harmful to cell growth. In addition, It is expected to recover hGM-CSF simultaneously with cell growth. Using this method, maximum hGM-CSF concentration at 1.64 ng/mL was obtained on day 3.

• Journal of the Korean Applied Science and Technology
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• v.29 no.4
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• pp.577-584
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• 2012

The simultaneous analysis of sun screen agents in commercial cosmetic samples was carried out by High Perfomance Liquid Chromatography(HPLC). The cosmetic samples are directly dissolved in Tetrahydrofurane(THF) and filtered using $0.45{\mu}m$ filter. The water/methanol/THF was used for the mobile phase of gradient conditions. An Extend C18 reversed-phase column and the selected UV/Visible detector was applied. The analysis results of HPLC showed good linearity with correlation coefficient of $r^2$=0.9992 in the rage of $50{\sim}800{\mu}g/mL$ and detection limit of $0.01{\mu}g/mL$.