• Applied Chemistry for Engineering
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• v.32 no.2
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• pp.180-189
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• 2021

N-Heteroaryl carbazoles were synthesized with thermal heating in the presence of Cu(I) catalyst and used as main ligands for the preparation of heteroleptic Ir(III) complexes. In these Ir(III) complexes, 6-membered ring structures of Ir-ligand chelation were found by single crystal X-ray diffraction. The blue shift of photoluminescence for Ir(III) complexes was observed in the case of the strong bond formation between Ir and ancillary ligands. It also has been clearly shown that the higher electron density of heteroaryl aromatic ring influenced shorter maximum photoluminescence wavelength (λmax) of Ir(III) complexes. Since the new Ir(III) complexes showed good phosphorescent emission, they could be potentially used as OLED materials in the emission Layer.

• Polymer(Korea)
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• v.29 no.5
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• pp.433-439
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• 2005

The copolymers were prepared by the emulsion copolymerization of fluoroalky lacrylate-stearylacrylate-m-isopropenyl-${\alpha},\;{\alpha}'$-dimethylbenzyl isocyanate (TMI) in order to obtain water repellent polymers. The respective copolymerization rates of the three monomers considerably depended upon the use of the nonionic emulsifier and the nonionic-cationic mixed emusifier, and the optimum conditions were obtained. The particle sizes of the copolymers were in the range of 105 to 222nm. The particle sizes of the copolymers prepared by the use of the mixed emulsifiers were smaller than those of the copolymers prepared by the use of the nonionic emulsifier. The reactions of both TMI-N-methyl acetamide and TMI-cellobiose did not take place. However, the reaction of TMI-n-butylamine occurred. The water contact angles before and after washing three times for nylon and poly(ethylene terephthalate) (PET) fabrics coated with the copolymer prepared by the use of mixed emulsifier were about $139^{\circ}\;and\;133^{\circ}$ Therefore, the copolymer showed good durable repellency for nylon and PET.

• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.497-503
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• 2008

A variety of techniques has been employed in order to reduce problems caused by the crystallization of paraffin and saturated fatty acid esters in diesel fuel containing biodiesels. Methacrylate copolymers are known as additives which reduce the pour point and cold filtering plugging point (CFPP) of diesel fuels. This paper describes the synthesis, characterization and low temperature properties, having as an initial step the synthesis of the alkyl methacrylate monomers by esterification of methacrylic acid with C12, C18, and C22 fatty alcohols. The copolymerization of these monomers with styrene was then performed, with molar ratios of 30:70, 50:50 and 70:30 for styrene:alkyl methacrylate. All copolymers were characterized by $^1H-NMR$, FT-IR, and gel permeation chromatography (GPC). The poly(styrene-co-alkyl methacrylate)s (PStmSMAn) leads to a large reduction in the pour point and CFPP of poly(styrene-co-alkyl methacrylate) in ultra low sulfur diesel (ULSD) and BD5 with treated 100~5000 ppm of poly(styrene-co-alkyl methacrylate). BD5 fuel containing 5000 ppm of the copolymer (PSt82SMA18) showed a $25^{\circ}C$ and $9^{\circ}C$ reduction in their pour points and CFPP, respectively.

• Korean Journal of Food Science and Technology
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• v.45 no.4
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• pp.508-514
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• 2013

2Department of Marine Molecular Biotechnology, College of Life Science, Gangneung-Wonju National University Recently, we reported that diarylheptanoid hirsutenone (HST) effectively inactivated T lymphocytes. However, it has not been evaluated whether HST is involved in calcineurin or calmodulin inactivation. In the present study, cells were treated with T-cell inhibitors with or without HST. Our results revealed that HST successfully inhibited expression of T-helper type I (Th1) and Th2 cytokines. Co-treatment with HST and nuclear factor-activated T cell (NFAT) activation inhibitor III (INCA-6) showed a more sensitive effect than that with other inhibitors, suggesting that HST contributes to inhibition of dephosphorylation of NFAT in the cytosol. HST up-regulated cell cycle arrest genes and inhibited the growth of Staphylococcus aureus. These effects were confirmed in an NFAT electrophoretic-mobility shift assay via successful inhibition of NFAT translocation and in the histological recovery in a 2,4-dinitrochloro benzene-induced in vivo model. Taken together, HST was shown to effectively inhibit T-cell activation via inhibition of cytosolic NFAT dephosphorylation, similar to INCA-6.

• Korean journal of applied entomology
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• v.37 no.2
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• pp.179-185
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• 1998

The effect of physiological factors of beet armyworm, Spodoptera exigua (Hubner), on esterase variation was analyzed by comparing electrophoretic esterase isozymes. Each esterase isozyme was also characterized by substrate and inhibitor specificities. A total of 28 esterase isozymes were separated on 10% nondenaturing polycarylamide gel electrophoresis (PAGE). These isozymes were denoted from El to E28 according to cathodal migration distances. There was a variation in esterase isozymes among developmental stages. Larvae and pupae had more isozymes than did adults. Eggs had only eight isozymes. The isozymes of El and E2 were specific only in the first instar larvae. Esterases also showed variation according to different tissues. More kinds of esterase isozymes were found in epidermis and gut tissues than in hemolymph and fat body. Some isozymes were specific in epidermis (from El to E6), gut (E10, El 1, E25, E26, and E27), and hemolymph (E18). Among 10 naphthyl esters, a-naphthyl propionate was the most reactive substrate to the esterase isozymes. The isozymes were classified into cholinesterases (El0 and E24), arylesterases (E4, E9, E17, E19, E21, and E23), and carboxylesterases (the others) on the basis of inhibition by the esterase inhibitors-eserine, dichlorovos, moncrotophos, and paraoxon.