• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2385-2390
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• 2011

Preparation of ammonium dihydrogenphosphate supported on alumina ($NH_4H_2PO_4/Al_2O_3$) and its primary application as a solid acid supported heterogeneous catalyst to the synthesis of 1,2,4,5-tetrasubstituted imidazoles by a one-pot, four-component condensation of benzil, aromatic aldehydes, primary amines, and ammonium acetate under thermal solvent-free conditions were described. The results showed that the novel catalyst has high activity and the desired products were obtained in high yields. Furthermore, the products could be separated simply from the catalyst, and the catalyst could be recycled and reused with only slight reduction in its catalytic activity. Characterization of the catalyst was performed by FT-IR spectroscopy, the $N_2$ adsorption/desorption analysis (BET), thermal analysis (TG/DTG), and X-ray diffraction (XRD) techniques.

• Bulletin of the Korean Chemical Society
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• v.33 no.8
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• pp.2553-2559
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• 2012

The adsorption properties of benzene, toluene, p-xylene in MCM-41 with heterogeneous and cylindrical pore were studied using grand canonical ensemble Monte Carlo simulation. The simulated isotherms were compared with experimental ones, and the different adsorption behaviors in MCM-41 with pore diameters of 2.2 and 3.2 nm were investigated. The simulated adsorption amounts above the capillary-condensation pressure agreed with the experimental ones. The simulation results showed that most molecular planes were nearly parallel to the pore axis. This orientation was not affected by the molecular position in the pore. The molecular planes were nearly parallel to the pore surface for the adsorbate molecules close to the pore wall, and the molecules in the MCM-41 with the pore diameter of 3.2 nm were ordered along the pore axis.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2532-2534
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• 2009

A facile and efficient synthetic route has been developed for the polyhydroquinoline via four component reactions of aldehydes, dimedone, ethyl acetoacetate and ammonium acetate in the presence of catalytic amount of scolecite in ethanol at 70 ${^{\circ}C}$ through Hantzsch reaction. This method gives remarkable advantages such as simple work-up procedure, environmentally friendly, inexpensive, non-toxic and recyclable catalyst, shorter reaction time along with excellent yields.

• Applied Chemistry for Engineering
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• v.25 no.2
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• pp.215-221
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• 2014

A simple heterogeneous system has been developed by using base treated manganese dioxide (B-$MnO_2$) for the aerobic oxidation of amines under mild reaction conditions of 1 atm of air and $50^{\circ}C$ in hexane. This system was highly efficient to oxidize various kinds of primary or secondary amines including aliphatic, aromatic, and hetero-atomic ones under the applied reaction conditions. Amines were oxidized to nitriles or diimines by the self-condensation or oxidative dehydrogenation through imine intermediate. The B-$MnO_2$ was reused for at least 5 times without any loss of its catalytic performance and showed its cost effectiveness, easy workup, and easy separation of the products for achieving the protocol of green chemistry.

• Nuclear Engineering and Technology
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• v.28 no.1
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• pp.44-55
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• 1996

For the purpose of controlling the release of radioiodine to the environment in nuclear power plants, adsorption characteristics of elemental iodine and methyl iodide on the base carbon and 2%, 5% TEDA impregnated carbons were studied. The amounts of adsorption of elemental iodine and methyl iodide on the carbons were compared with Langmuir, Freundlich, Sips and Dubinin-Astakhov(DA) isotherm equations. Adsorption data were well correlated by the DA equation based on the potential theory. Adsorption energy distributions were obtained from the parameters of the DA equation derived from the condensation approach method. For the adsorption of methyl iodide and elemental iodine-carbon system, the DA equation can be well expressed by the degree of heterogeneity of the micropore system because the surface is nonuniform when its potential energy is unequal. The adsorption energy distribution wes investigated to find a surface heterogeneity on the carbon. The surface heterogeneity for iodine-carbon system is highly affected by the adsorbate-adsorbent interaction as well as the pore structure. The surface heterogeneity increases as a content of TEDA impregnated increases. The adsorption nature of methyl iodide on carbon turned out to be more heterogeneous than that of elemental iodine.

• Bulletin of the Korean Chemical Society
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• v.31 no.10
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• pp.2835-2840
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• 2010

A series of $MoO_3/CeO_2-ZrO_2$ catalysts with different Mo content (8 - 20 wt %) were prepared by simple co-precipitation followed by impregnation method and were characterized by X-ray diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), energy dispersive spectroscopic (EDS) techniques. The prepared materials were tested for catalytic activity by the synthesis of benzimidazole derivatives using condensation of aromatic aldehydes and o-phenylenediamine by conventional and microwave method. Obtained results reveal that the catalytic activity increases with increase in Mo wt % loading. The best catalytic activity was obtained with 20 wt % $MoO_3/CeO_2-ZrO_2$. The particle size or crystallite size was estimated using Debye-Scherrer equation. After completion of reaction, the catalyst can be recovered efficiently and reused with consistent activity.

• Applied Chemistry for Engineering
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• v.27 no.5
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• pp.537-542
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• 2016

In this study, we have prepared mesophase pitch from pyrolysis fuel oil (PFO) by heterogeneous reforming process. This process was conducted by direct fluorination at various temperature and followed by the heat treatment at $390^{\circ}C$. The reformed pitch was then investigated by softening point analysis, elemental analysis, fourier-transform infrared spectroscopy, high resolution X-ray diffraction and polarization microscope analysis. Carbon contents of reformed pitch increased according to increasing the reaction temperature of fluorination, while oxygen, nitrogen and sulfur contents were completely eliminated. As the fluorination temperature increased, the creation, growth, coalescence and alignment process of mesophase spheres were observed. Also the interlayer spacing of carbon hexagonal planar structure decreased, while its crystalline size increased. In addition, aromatic ring compound contents increased by the condensation polymerization of aliphatic compound. These results can be attributed to the radical reactivity of the fluorine increased as the reaction temperature increased. It was considered that the fluorination reaction could help PFO to generate aromatic compounds, via promoting polymerization by radical reaction.

• Applied Microscopy
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• v.32 no.4
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• pp.303-310
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• 2002

Spermatogenesis and sperm ultrastructure are investigated by means of light and transmission electron microscopy in the equilateral venus, Gomphina veneriformis which is dominant bivalve in the east coast of Korea. In the active spermatogenic season, testis consists of numerous spermatogenic follicles which is contains germ cells in the different developmental stage. The spermatogonia attached to spermatogenic follicle wall and has a large nucleus with electron-dense nucleolus. The spermatocytes are characterized by appearance of synaptonemal complex and well-developed Golgi complex. Nucleus of spermatid consists of numerous heterogeneous granules with high electron density. Karyoplasmic condensation, acrosome and flagellum formations are observed during spermiogenesis. Testicular matured sperms of sperm bundle consists of head, midpiece and tail. The head is about $8.5{\mu}m$ long and comprises a long nucleus and a bullet-like acrosome ($8.5{\mu}m$ in length). Acrosomal rod of microfilaments is observed in the lumen between nucleus and acrosome. The midpiece has four mitochondria. And tail has the typical '9+2' microtubule system.

• Korean Chemical Engineering Research
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• v.48 no.3
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• pp.332-336
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• 2010

Ionic liquid immobilized on mesoporous amorphous silica was prepared from the coupling of 1-(triethoxysilylpropyl)-3-n-alkyl-imidzolium halides with tetraethyl orthosilicate(TEOS) through template-free condensation under strong acidic conditions. The immobilized 1-n-butyl-3-methyl imidazolium bromide ionic liquid on amorphous silica(BMImBr-AS) was proved to be an effective heterogeneous catalyst for the synthesis of dimethyl carbonate(DMC) from transesterification of ethylene carbonate(EC) with methanol. High temperature, high carbon dioxide pressure and long reaction time were favorable for the reactivity of BMImBr-AS. Kinetic studies based on two step reactions revealed that the proposed reaction model fitted well the experimental data. The apparent activation energy was estimated to be 67.4 kJ/mol.

• Journal of dental hygiene science
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• v.23 no.3
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• pp.216-224
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• 2023

Background: Smilax glabra has various pharmacological activities and is widely used as a herbal medicine. Although the incidence of oral cancer is low, the recurrence rate is high, and the 5-year survival rate is poor. It is necessary to search for anticancer drugs that increase the effect of cancer chemotherapy on heterogeneous oral tissues and reduce the side effects on normal cells. This study aimed to investigate the effects and mechanism of ethanol extract of Smilax glabra (EESG) as an anticancer drug for oral cancer. Methods: Smilax glabra root components extracted with 70% ethanol were used to analyze their effects on cancer cells. A 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide assay was performed for cytotoxicity analysis. Flow cytometry was performed to determine the cell cycle phase distribution. To observe apoptotic cells, terminal deoxynucleotidyl transferase dUTP nick end labeling and γH2AX were detected by fluorescence microscope. The protein levels of cleaved PARP and caspase were analyzed using western blotting. The activation of procaspase-3 was confirmed by measuring caspase-3 activity. Results: EESG was no cytotoxic to normal gingival fibroblast but was high in YD10B oral squamous cell carcinoma (OSCC) cells. EESG treatment increased the subdiploid DNA content of YD10B cells by assessing DNA content distribution. Chromatin condensation and DNA strand breaks increased in YD10B cells treated with EESG. EESG-treated YD10B cells had high Annexin V and low propidium iodide levels, confirming that early apoptosis was induced. In addition, increased levels of γH2AX foci, a marker of DNA damage, were observed in the nuclei of EESG-treated YD10B cells. The EESG-treated YD10B cells also exhibited decreased procaspase-3 and procaspase-9 levels, increased PARP cleavage and caspase-3 activity. Conclusion: These results indicate that EESG inhibited cancer cell proliferation by inducing apoptosis in YD10B OSCC cells.