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Photo-Induced Cytotoxicity of Prodigiosin Analogues
Gyungse Park*,John T. Tomlinson,Jacob A. Misenheimer,Gregory L. Kucera,Richard A. Manderville* 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.1
Prodigiosin (1) is the parent member of a class of polypyrrole natural products that exhibit promising anticancer activities. They can facilitate copper-promoted oxidative DNA damage by binding to copper ions, and this activity is thought to represent their mechanism of cytotoxicity in the dark. They also possess photoinduced cytotoxicity, although 1 is too toxic in the dark to be used effectively for the treatment of cancer by photodynamic therapies. To circumvent dark toxicity by prodigiosins, the semi-synthetic analogue 2, in which the N-pyrrolic atoms of 1 are methylated to block copper coordination, and the synthetic phenyl analogues 3 and 4, which lack the copper-coordinating A-pyrrole ring of 1, were tested for their ability to inhibit colony formation of HL-60 cancer cells in the absence and presence of visible light (l > 495 nm). Our results show that 2-4 lack cytotoxicity in the dark, but are able to inhibit colony formation of HL-60 cells following irradiation for 30 min. The synthetic derivative 4 exhibits photo-induced cytotoxicity similar to that of the natural product 1, demonstrating the potential use of prodigiosin-based compounds for treatment of cancers following irradiation with visible light.
Study of Stability and Proton Conductivity of Zn-based Metal–Organic Framework
Son Younghu,Rao Purna Chandra,Kim Jiyun,Park Gyungse,Yoon Minyoung 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.5
Among the various types of solid-state proton conductors (SSPCs), metal–organic frameworks (MOFs) have emerged as significant importance in the field of proton-exchange membrane fuel-cell (PEMFCs) applications. Herein, we have synthesized a three-dimensional trinuclear zinc-based metal–organic framework, denoted as Zn-SDC-MOF by modification of reported synthetic conditions, where stilbenedicarboxylic acid (H2SDC) and 4,40-bipyridine (bpy) are employed as an organic linker unit. With motivation of air stable trinuclear Zn-SDC MOFs, we have analyzed the water stability behavior of this compound. It resulted in exceptional water stability performance over 3 weeks as confirmed by powder X-ray diffraction (PXRD) analysis. Moreover, this MOF compounds have shown modest proton conductive performance of 0.8 × 10−3 S cm−1, at 95% relative humidity (RH) and 298 K.
Lee, Jaeho,Won, Sora,Shim, Joongpyo,Park, Gyungse,Sun, Ho-Jung,Lee, Hong-Ki The Korean Institute of Electrical and Electronic 2014 Transactions on Electrical and Electronic Material Vol.15 No.4
Si-carbon composites as anode materials for lithium rechargeable batteries were prepared simply by mixing Si nanoparticles with carbon black and/or graphite through a solution process. Si nanoparticles were well dispersed and deposited on the surface of the carbon in a tetrahydrofuran solution. Si-carbon composites showed more than 700 mAh/g of initial capacity under less than 20% loading of Si nanoparticle in the composites. While the electrode with only Si nanoparticles showed fast capacity fading during continuous cycling, Si-carbon composite electrodes showed higher capacities. The cycle performances of Si nanoparticles in composites containing graphite were improved due to the role of the graphite as a matrix.
Hao Nguyen Thi My,Ahmed Sheraz,An Jung‐Chul,Sun Ho‐Jung,Park Gyungse,Shim Joongpyo 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.9
Co and carbon nanotube (CNT) were prepared as anode materials to be used in lithium rechargeable batteries from the zeolitic-imidazolate framework-67 (ZIF-67) using the solvothermal method. By annealing ZIF-67 at different temperatures between 400 and 700 C, the carbon framework was changed to CNTs, and Co or Co3O4 nanoparticles were embedded in the CNTs (Co or Co3O4/CNT). The Co/CNT was converted to Co-Co3O4/CNT by further treatment at 160 C in air. The Co3O4/CNT showed high initial capacities (1582 mAh/g) but poor capacity retention during cycling. However, the air treatment of the Co/CNT at 160 C enhanced its discharge capacity (935 mAh/g) and capacity retention during cycling.