• Korean Journal of Materials Research
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• v.27 no.6
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• pp.307-311
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• 2017

Organometal halide perovskite materials, due to the tunability of their electronic and optical properties by control of composition and structure, have taken a position of significant importance in optoelectronic applications such as photovoltaic and lighting devices. Despite numerous studies on the structure - property relationship, however, practical application of these materials in electronic and optical devices is still limited by their processability during fabrication. Achieving nano-sized perovskite particles embedded in a polymer matrix with high loading density and outstanding photoluminescence performance is challenging. Here, we demonstrate that the careful control of nanoparticle formation and growth in the presence of poly(methyl methacrylate) results in perovskite nanoparticle - polymer nanocomposites with very good dispersion and photoluminescence. Furthermore, this approach is found to prevent further growth of perovskite nanoparticles, and thus results in a more uniform film, which enables fabrication using the perovskite nanoparticles.

• Korean Journal of Materials Research
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• v.20 no.6
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• pp.312-318
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• 2010

Multilayer Poly methyl methacrylate (PMMA)/ Poly vinyl alcohol (PVA) bone plates were fabricated using electrospinning and in vitro investigations were carried out for pre-clinical biocompatibility studies. The initial cellular cytotoxicity of the methacrylate (PMMA)/ Poly vinyl alcohol (PVA) bone plates was measured by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay using fibroblast-like L-929 cells. Cellular adhesion and differentiation studies were carried out using osteoblast-like MG-63 cells. As simulated body fluid (SBF) contains the same ionic concentration of body fluid and any bioactive material tends to deposit bone-like apatite on the samples surfaces into the SBF, in vitro bioactivity of the multilayer bone plates were investigated using SBF. We also studied the internal organization and tensile strength of the multilayer PMMA/PVA bone plates using micro-computed topography (${\mu}$-CT) and universal testing instrument (UTI, Korea) respectively. The cellular cytotoxicity study with MTT confirmed that the cellular viability was 78 to 90% which indicates good cyto-compatibility. Scanning electron microscopic findings revealed a good attachment and adhesion phenomenon of MG-63 cells onto the surfaces of the samples. Cellular differentiation studies also showed that osteogenic differentiation was switched on in a timely manner and affirmed along with that of the control group. Bone-like apatite formation on the surfaces was confirmed within 14 days of SBF incubation. Initial organizations of the multilayer PMMA/PVA bone plates were characterized as dense and uniform. The tensile strength of the post-pressing electronspun mat was higher than that of the pre-electronspun mat. These results suggest that a multilayer PMMA/PVA bone plate system is biocompatible, bioactive and a very good alternative bone plate system.

• The Korean Journal of Pesticide Science
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• v.7 no.3
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• pp.198-206
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• 2003

To assess potential risk of the benzimidazole fungicides, their cytotoxicities were evaluated. Activities of LDH(Lactic dehydrogenase) in the culture fluid of CHL(chinese hamster lung) fiberoblast cell treated with 4.0, 16.0 or $32.0{\mu}g/mL$ of carbendazim for 24 hours were elevated 2.16, 2.94 and 2.64 folds compared to the control, respectively. DNA synthesis was inhibited by 45% at $2.0{\mu}g/mL$ of carbendazim. Benzimidazole fungicides showed high toxicity to cell and mitochondria of CHL cell by Giemsa and MTT (3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide) assay. $IC_{50}$ by the Giemsa assay of thiophanate-methyl, benomyl, carbendazim and captafol were over 125, 1.2, 30.0 and $0.3{\mu}g/mL$, respectively. $IC_{50}$ by the MTT assay of thiophanate-methyl, benomyl, carbendazim and captafol were over 125, 18.7, 20.4 and $2.6{\mu}g/mL$, respectively. Inhibitory concentration of cell median proliferation by SRB (sulforhodamin B) assay for thiophanate-methyl, carbendazim, benomyl, and captafol were 17.4, 5.3, 1.5 and $0.5{\mu}g/mL$, respectively. Accordingly, benzimidazole fungicides inhibited DNA synthesis, mitochondrial function, cell proliferation and induced cell necrosis.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.218-218
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• 1994

화합물 9-methoxy-6-oxo-3,4,4a,5-tetrahydro-3-hydroxy-2,2-dimethyl-naphtho[1,2〕pyran(1)의 전구물질인 7-methoxy-4-oxo-2-prenyl-1-tetralol을 다음과 같은 방법으로 합성하였다. 7-Methoxy-$\alpha$-tetralone에 LDA를 처리한 후, prenyl bromide를 반응시켜 7-methoxy-2-prenyl-1-tetralone을 제조했다 (수율 66%). 7-Methyl-2-prenyl-1-tetralone을 L-seleclride로 환원하여 cis-2-prenyl-1-tetralol을98% 수율로 얻었다. cis-2-Prcnyl-1-tetralol을pyridine 존재하에서 acetic anhydride로서acetylation한 다음 PDC로 산화시켜 4-acetoxy-3-prenyl-1-tetralone을 합성하였다 (수율 45%). cis-4-Acetoxy-3-prenyl-1-tetralone을 가수분해하여 cir-7-methoxy-4-oxo-2-prenyl-1-tenalol을 합성하였다. 6,7-Dimethoxy-4-oxo-2-prenyl-1-letralol도 동일한 방법으로 합성하였다.

• Proceedings of the KAIS Fall Conference
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• 2007.05a
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• pp.264-266
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• 2007

지구의 온난화를 가속시키는데 일조하고 있는 이산화탄소($CO_{2}$)와 Epoxy를 Tetrabutylammonium bromide를 촉매로 하여 초임계 상태에서 반응시켜 2차 전지의 전해질 물질로 사용 가능한 4-ethyl-l,3-dioxolan-2-one, 4-methyl-1,3-dioxlan-2-one, 4-phenyl-1,3-dioxolan-2-one, 4-Chloromethyl-1,3-dioxolan-2-one을 합성하여 $^{l}H-NMR$을 이용하여 분석하였다.

• YAKHAK HOEJI
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• v.28 no.5
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• pp.275-282
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• 1984

The interaction between azo dyes and cationic surfactant was studied by absorption spectroscopy and fluorescent Rayleigh scattering. In order to presume the structure of formed micelle, methyl orange and ethyl orange as azo dyes and cetyltrimethylammonium bromide (CTAB) as cationic surfactant were used. Infomations about interaction parameter including absorption maxima, optimal conditions, and intensity of fluorescent Rayleigh scattering were obtained. When azo dyes and CTAB are formed 1 : 1 complex, it showed the strongest intensity of fluorescent Rayleigh scattering. On going from mixed micelle to homomicell, It suggests successively several intermediate steps of complex structure which can be distinguished clearly from one another.

• Toxicological Research
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• v.11 no.2
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• pp.187-192
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• 1995

The cytotoxic effects of hydrogen peroxide and neuroprotective effects of a variety of agents were investigated in newborn mouse forebrain tissue culture. In our experiments, oxygen radical was generated enzymatically by glucose oxidase and the values were expressed as a percentage of number of living cells by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Cytotoxicity of oxygen radicals was prevented by catalase and (N, N, N', N', -tetrakis (2-pyridylmethyl) ethylenediamine (TPEN), but N-tetra-ot-butyl-phenylnitrone (PBN), and deferoxamine (DFX), failed to show protective effects against oxygen radicals. Antagonists of the N-methyl-D-aspartate (NMDA) receptor, D-2-amino-5-phosphonovaleric acid (APV), 7-chlorokynurenic acid (CKA), and MK801 (a non-competitive NMDA antagonist) were also not effective in blocking neurotoxicity induced by glucose oxidase generated oxygen radicals.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.5
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• pp.668-677
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• 2004

This study examines the effects and influences of fumigation on the antimicrobial treatment of excavated dresses in two different museum settings using chemical composite of Methyl Bromide and Ethylene Oxide. The microbial test indicated that the prewashed samples contained Micrococcus, Bacillus, Staphylococcus, and some unidentified fungi and that the total number of microbes decreased after washing. While it was observed that most germs were removed immediately after fumigation, Bacillus was still found and its number even increased. After 5 months, the number of microbes found in Museum A was smaller than Museum B, which shows that Museum A equipped with better environment control facility was superior to Museum. B in terms of exhibition and preservation of dresses against organic damages. In addition, the result indicates that fumigation is an effective measure against the growth and reproduction of microorganisms, considering that the number of microorganisms decreased after fumigation. The color of test sample showed immediate change after fumigation but color difference became stabilized and decreased with the passage of time. The test samples from both museums showed similar patterns.

• Archives of Pharmacal Research
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• v.23 no.2
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• pp.104-111
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• 2000

Stereochemical isomers with hydroxy groups were synthesized by reacting 2-(dimethoxy-methyl)cyclohexanone with propargylmagnesium bromide. The stereo chemical structures were identified by NMR spectral interpretation and the geometry optimization. To assist the NMR interpretation, geometry optimization based on semi-empirical AM1 and PM3 methods was applied. Throughout this study, the structures of the two isomers were all determined and $^{1}H$ and $^{13}C$ NMR spectra were fully assigned. It was proven that the less polar isomer is an axial alcohol and the more polar one is an equatorial alcohol.

• YAKHAK HOEJI
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• v.37 no.2
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• pp.113-118
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• 1993

3-Phenyl-5, 6, 7, 8-tetrahydrothiazolo[3, 2-$\alpha$][1, 3]diazepine, which has pharmaceutical activities, was reacted with phenyl isothiocyanate to give 3-phenyl-9-phenyl(thiocarbamoyl)-5, 6, 7, 8-tetrahydrothiazolo[3, 2-$\alpha$][1, 3]diazepi nium-betaine. New biheterocyclic compounds were prepared by the ring transformation reaction of the above reactive betaine with $\alpha$-haloesters and $\alpha$-haloketones such as ethyl bromoacetate, methyl bromoacetate, chloroacetone, and 4'-methoxyphenacyl bromide, respectively. In each ring transformation reaction, two major products supposed to be geometrical isomers were obtained.