• Journal of the Korean Chemical Society
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• v.55 no.3
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• pp.436-443
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• 2011

The solid complexes of La(III), Ce(III), Pr(III), Nd(III), Sm(III) and Gd(III) with 4-hydroxy-3-(1-{2-(2,4-dihydroxy-benzylidene)-amino phenylimino}-ethyl)-6-methyl-pyran-2-one ($H_2$L) derived from o-phenylenediamine, 3-acetyl-6-methyl-(2H)pyran,2,4(3H)-dione (dehydroacetic acid or DHA) and 2, 4-dihydroxy benzaldehyde have been synthesized and characterized by elemental analysis, conductometry, magnetic susceptibility, UV-visible, FT-IR, $^1H$-NMR, X-ray diffraction, thermal analysis study, and screened for antimicrobial activity. The FT-IR spectral data suggest that the ligand behaves as a dibasic tetradentate ligand with ONNO donor atoms sequence towards central metal ion. From the microanalytical data, the stoichiometry of the complexes has been found to be 1:1 (metal: ligand). The physico-chemical data suggests distorted octahedral geometry for La(III), Ce(III), Pr(III), Nd(III), Sm(III) and Gd(III) complexes. The X-ray diffraction data suggests monoclinic crystal system for La(III) and Ce(III) and orthorombic crystal system for Pr(III) and Nd(III) complexes. Thermal behavior (TG/DTA) of the complexes was studied and kinetic parameters were determined by Horowitz-Metzger and Coats-Redfern methods. The ligand and its metal complexes were screened for antibacterial activity against Staphylococcus aureus, Escherichia coli, Bacillus Sp. and fungicidal activity against Aspergillus Niger, Trichoderma and Fusarium oxysporum.

• Korean Journal of Clinical Laboratory Science
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• v.41 no.2
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• pp.83-92
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• 2009

This study was undertaken to examine the effect of oxidants on membrane transport function in renal epithelial cells. Hydrogen peroxide ($H_2O_2$) was used as a model oxidant and the membrane transport function was evaluated by measuring $Na^+$-dependent phosphate ($Na^+$-Pi) uptake in opossum kidney (OK) cells. $H_2O_2$ inhibited $Na^+$-Pi uptake in a dose-dependent manner. The oxidant also caused loss of cell viability in a dose-dependent fashion. However, the extent of inhibition of the uptake was larger than that in cell viability. $H_2O_2$ inhibited $Na^+$-dependent uptake without any effect on $Na^+$-independent uptake. $H_2O_2$-induced inhibition of $Na^+$-Pi uptake was prevented completely by catalase, dimethylthiourea, and deferoxamine, suggesting involvement of hydroxyl radical generated by an iron-dependent mechanism. In contrast, antioxidants Trolox, N,N'-diphenyl-p-phenylenediamine, and butylated hydroxyanisole did not affect the $H_2O_2$ inhibition. Kinetic analysis indicated that $H_2O_2$ decreased Vmax of $Na^+$-Pi uptake with no change in the Km value. Phosphonoformic acid binding assay did not show any difference between control and $H_2O_2$-treated cells. $H_2O_2$ also did not cause degradation of $Na^+$-Pi transporter protein. Reduction in $Na^+$-Pi uptake by $H_2O_2$ was associated with ATP depletion and direct inhibition of $Na^+$-$K^+$-ATPase activity. These results indicate that the effect of $H_2O_2$ on membrane transport function in OK cells is associated with reduction in functional $Na^+$-pump activity. In addition, the inhibitory effect of $H_2O_2$ was not associated with lipid peroxidation.

• Journal of Life Science
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• v.16 no.2 s.75
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• pp.206-212
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• 2006

In order to synthesize novel anticonvulsants, we researched that the reactions of diamines with 2,5-dimethoxytetrahydrofuran and 1,3-acetonedicarboxylic acid. The reaction of ethylenediamine with 2,5-dimethoxytetrahydrofuran and 1,3-acetonedicarboxylic acid afforded 8-(2-pyrrol-1-yl-ethyl)-8-aza-bicyclo[3,2,1]octan-3-one (yield; 5.0%) and 1,2-di-(8-aza-bicyclo[3,2,1]octan3-onyl)ethane (yield; 17.0%). In case of 1,3-diaminopropane, 8-(3-pyrrol-1-yl-propyl)-8-aza-bicyclo[3,2,1]octan-3-one(yield; 6.0%) and 1,3-di-(8-aza-bicyclo[3,2,1]octan-3-onyl)propane (yield; 21.0%) were obtained. In case of 1,8-diaminooctane, 8-(8-pyrrol-1-yl-octyl)-8-aza-bicyclo-[3,2,1]octan-3-one (yield; 2.6 %) and 1,8-di-(8-aza-bicyclo[3,2,1]octan-3-onyl)octane (yield; 24.9%) were obtained. In diaminobenzene reactions, synthetic yields of 8-aza-bicyclo-[3,2,1]octan-3-one derivatives were higher than those of pyrrole derivatives because re actions were done under room temperature. The longer the carbon chain of diaminoalkane is, the more reactive N atom is due to more electron donating effect, and the less steric hindrance around the carbon gave the higher chemical yields. The reaction of p-phenylenediamine as a diaminobenzene with 2,5-dimethoxyte-trahydrofuran and 1,3-acetonedicarboxylic acid produced p-dipyrrolylbenzene (yield; 4.0%), 8-(4-pyrrol-1-yl-phenyl)-8-aza-bicyclo[3,2,1]octan-3-one (yield; 12.0%), and 1,4-di-(8-aza-bicyclo[3,2,1]octan-3-onyl)benzene (yield; 59.0%). In case of m-phenylenediamine, 8-(3-pyrrol-1-yl-phenyl)-8-aza-bicyclo[3,2,1]octan-3-one(yield; 2.0%) and 1,3-di-(8-aza-bicyclo[3,2,1]octan-3-onyl)benzene (yield ; 28.0%) were obtained. But, synthesis of 1,2-di-(8-aza-bicyclo[3,2,l]octan-3-onyl)benzene by treatment of o-phenylenediamine was not successful, presumably due to the steric hindrance of 8-aza-bicyclo-[3,2,1]octan-3-one rings.

• Korean Journal of Clinical Laboratory Science
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• v.43 no.4
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• pp.161-170
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• 2011

Quercetin is one of the most distributed flavonoids in the plant kingdom and occurs naturally in a wide range of fruits and vegetables. This study was undertaken to determine whether quercetin exerts beneficial effect against necrotic and apoptotic cell death induced by hydrogen peroxide ($H_2O2$) in intestinal cells using the human-derived cultured T84 colonic epithelial cell line. Necrotic cell death was induced by exposing cells to 0.5 mM $H_2O_2$ for 2 h and apoptosis was induced by incubating cells in normal culture medium for 18 h following exposure of cells to 0.5 mM $H_2O2$ for 2 h. Cell viability was evaluated by the trypan blue exclusion assay and apoptosis was assessed by Hoechst 33258 staining and flow cytometry. $H_2O_2$ induced necrotic cell death in a time and dose-dependent fashion. Both necrotic and apoptotic cell deaths were not prevented by the antioxidants N,N'-diphenyl-p-phenylenediamine(DPPD) and Trolox, whereas both cell deaths induced by the organic hydroperoxide t-butylhydroperoxide (tBHP) were prevented by DPPD, suggesting that $H_2O_2$ induces cell death through a lipid peroxidation-independent mechanism. $H_2O2$-induced necrotic death was prevented by deferoxamine and 3-aminobenzamide, while the apoptotic cell death was not affected by these agents. Quercetin prevented both necrotic and apoptotic cell deaths induced by $H_2O_2$ in a dose-dependent manner. $H_2O_2$ caused activation of poly (ADP-ribose) polmerase (PARP), which was inhibited by deferoxamine, 3-aminobenzamide, and quercetin, but not DPPD. These results indicate that quercetin inhibits both necroticand apoptotic deaths of T84 cells. The anti-necrotic effect of quercetin may be attributed to its iron chelator activity rather than a direct $H_2O_2$ scavenging capacity and antioxidant. The present study suggests that quercetin may play a therapeutic role in the treatment of human gastrointestinal diseases mediated by oxidants.

• Biomedical Science Letters
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• v.8 no.4
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• pp.251-256
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• 2002

This study was undertaken to determine the underlying mechanisms of reactive oxygen species-induced cell injury in renal epithelial cells and whether there is a difference in the role of lipid peroxidation between freshly isolated renal cells and cultured renal cells. Rabbit renal cortical slices were used as a model of freshly isolated cells and opossum kidney (OK) cells as a model of cultured cells. Cell injury was estimated by measuring lactate dehydrogenase (LDH) release in renal cortical slices and frypan blue exclusion in OK cells. $H_2O$$_2$ was used as a drug model of reactive oxygen species. $H_2O$$_2$ induced cell injury in a dose-dependent manner in both cell types. However, renal cortical slices were resistant to $H_2O$$_2$ approximately 50-fold than OK cells. $H_2O$$_2$-induced cell injury was prevented by thiols (glutathione and dithiothreitol) and iron chelators (deferoxamine and phenanthroline) in both cell types. $H_2O$$_2$-induced cell injury in renal cortical slices was completely prevented by antioxidants N,N-diphenyl-p -phenylenediamine and Trolox, but the cell injury was not affected by these antioxidants in OK cells. $H_2O$$_2$ increased lipid peroxidation in both cell types, which was completely inhibited by the antioxidants. These results suggest that $H_2O$$_2$ induces cell injury through a lipid peroxidation-dependent mechanism in freshly isolated renal cells, but via a mechanism independent of lipid peronidation in cultured cells.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.10a
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• pp.51-52
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• 1997

1. 서론 : 폴리이미드는 우수한 기계적 강도와 열적, 화학적 안정성으로 인해 최근 막분리 재료로 많이 연구 검토되고 있다. 대부분의 폴리이미드는 비교적 높은 선택도를 가지고 있으나 투과계수가 떨어지는 단점을 지니고 있어소 이를 극복하기 위한 많은 연구가 진행되어 왔다. 그 결과 투과계수를 크게 증가시킨 폴리이미드를 함성하였으나 선택도는 감소하여 투과특성의 상위한계를 넘지는 못하였다. 이 한계를 극복하기 의해서 복합잴를 이용하거나 UV, 플라즈마 처리에 의한 고분자막의 수식 등 많은 방법들이 연구되고 있다. 본 연구는 NaX형 제올라이트를 폴리이미드에 혼화시킨 막으로 산소/질소의 분리투과특성의 개선을 시도하였으며, NaX형 제올라이트와 폴리이미드 혼화방법, 혼화비율 등이 기체투과특성에 미치는 영향을 고찰하였다. 본 실험에 사용된 NaX형 제올라이트는 직접 합성하여 사용하였다. 폴리이미드는 2,3,5,6-Tetramethyl-1,4-phenylenediamine(p-TeMPD)과 (3,3,4,4'-dicarboxyphenyl)-hexafluoropropene-dianhydride(6FDA)로 합성한 6FDA-p-TeMPD 폴리이미드를 사용하였고, 그 투과계수는 122Barrer, 선택도$\alpha$$_{N_2/O_2}$ = 3.4이다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.264.2-264.2
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• 2013

Molecular layer deposition (MLD) is sequential, self-limiting surface reaction to form conformal and ultrathin polymer film. This technique generally uses bifunctional precursors for stepwise sequential surface reaction and entirely organic polymer films. Also, in comparison with solution-based technique, because MLD is vapor-phase deposition based on ALD, it allows epitaxial growth of molecular layer on substrate and is especially good for surface reaction or coating of nanostructure such as nanopore, nanochannel, nanwire array and so on. In this study, polyurea film that consisted of phenylenediisocyanate and phenylenediamine was formed by MLD technique. In situ Fourier Transform Infrared (FTIR) measurement on high surface area SiO2 substrate was used to monitor the growth of polyurethane and polyurea film. Also, to investigate orientation of chemical bonding formed polymer film, plan-polarized grazing angle FTIR spectroscopy was used and it showed epitaxial growth and uniform orientation of chemical bones of polyurea films.

• Bulletin of the Korean Chemical Society
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• v.8 no.6
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• pp.476-479
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• 1987

The macrocyclic nickel complex of the molecular formula[Ni($C_{32}H_{26}N_4$)] has been synthesized from the template condensation reaction between 1-benzoylacetone and o-phenylenediamine in the presence of nickel acetate. Protonation and deuterium exchange reactions of the demetallated macrocyclic ligand and the nickel complex have been carried out. The infrared, electronic and proton magnetic resonance spectral data of both compounds are compared and discussed; protonation of the macrocyclic ligand take place at the nitrogen atoms and all the amine protons undergo very rapid deuterium exchange while the methine protons undergo very slow exchange. On the other hand, protonation of the nickel complex occurs at the nitrogen atoms and only amine protons undergo rapid deuterium exchange. Protonation and deprotonation of the nickel complexes proceed reversibly.

• Journal of the Korean Electrochemical Society
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• v.14 no.2
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• pp.117-124
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• 2011

We demonstrate a new surface modification of high-voltage lithium cobalt oxide ($LiCoO_2$) cathode active materials for lithium-ion batteries. This approach is based on exploitation of a polarity-tuned gel polymer electrolyte (GPE) coating. Herein, two contrast polymers having different polarity are chosen: polyimide (PI) synthesized from thermally curing 4-component (pyromellitic dianhydride/biphenyl dianhydride/phenylenediamine/oxydianiline) polyamic acid (as a polar GPE) and ethylene-vinyl acetate copolymer (EVA) containing 12 wt% vinyl acetate repeating unit (as a less polar GPE). The strong affinity of polyamic acid for $LiCoO_2$ allows the resulting PI coating layer to present a highly-continuous surface film of nanometer thickness. On the other hand, the less polar EVA coating layer is poorly deposited onto the $LiCoO_2$, resulting in a locally agglomerated morphology with relatively high thickness. Based on the characterization of GPE coating layers, their structural difference on the electrochemical performance and thermal stability of high-voltage (herein, 4.4 V) $LiCoO_2$ is thoroughly investigated. In comparison to the EVA coating layer, the PI coating layer is effective in preventing the direct exposure of $LiCoO_2$ to liquid electrolyte, which thus plays a viable role in improving the high-voltage cell performance and mitigating the interfacial exothermic reaction between the charged $LiCoO_2$ and liquid electrolytes.

• Membrane and Water Treatment
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• v.8 no.3
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• pp.225-244
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• 2017

A novel thin-film nanocomposite (TFN) reverse osmosis (RO)/non-woven fabric (NWF) membrane was prepared by adding zinc oxide (ZnO) nanospheres ($30{\pm}10nm$) during the interfacial polymerization process of m-phenylenediamine (MPD) and trimesoyl chloride (TMC) on self-made polysulfone (PSF) membrane/polyester (PET) non-woven fabric support. The improved performance of TFN RO membrane was verified in terms of water contact angle (WCA), water flux, salt rejection, antifouling properties and chlorine resistance. The results showed that the WCA value of TFN RO surface had a continuous decrease with the increasing of ZnO content in MPD aqueous solution. The water flux of composite TFN RO membranes acquired a remarkable increase with a stable high solute rejection (94.5 %) in $1g{\cdot}L^{-1}$ NaCl aqueous solution under the optimized addition amount of ZnO (1 wt%). The continuous testing of membrane separation performance after the immersion in sodium hypochlorite solution indicated that the introduction of ZnO nanospheres also dramatically enhanced the antifouling properties and the chlorine resistance of composite RO membranes.