• Journal of Photoscience
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• v.9 no.2
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• pp.367-369
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• 2002

Chlorophyll (ChI) a' is the Cl3$^2$-epimer of ChI a which is the constituent of P700, the primary electron donor of Photosystem (PS) I, of a thrmophilic cyanobacterium, Synechococcus elongatus, whose structure was recently determined by X-ray crystallography. To determine whether PS I of diverse oxygenic photosynthetic organisms universally contain one molecule of ChI a ’, pigment compositions of thylakoid membranes and PS I complexes isolated from cyanobacteria, green algae, red algae and higher plants were determined by reversed-phase HPLC. The results show that involvement of one ChI a'molecule in PS I is the universal feature for Chi a-based PS I of oxygenic photosynthetic organisms.

• Journal of Photoscience
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• v.9 no.2
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• pp.59-62
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• 2002

In chilling-sensitive plants, the donor side of Photosystem II is inhibited by the chilling treatment in the dark, while the acceptor side of Photosystem I is inhibited by the chilling under the moderate light. Since the addition of inhibitors of electron transfer from Photosystem II protects Photosystem I from chilling induced photoinhibition of Photosystem I, inhibition or down-regulation of Photosystem II activity in vivo may also protect Photosystem I from photoinhibition. It was revealed that dark-chilling pretreatment actually protected Photosystem I from photoinhibition. The results imply that down-regulation of Photosystem II under stress conditions may have a role to protect Photosystem I from photoinhibition.

• Bulletin of the Korean Chemical Society
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• v.23 no.1
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• pp.119-122
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• 2002

Weakly coordinating anions show little affinity for binding to unfunctionalized iron(II) porphyrins. The electron-deficient 5, 10, 15, 20-tetrakis(pentafluorophenyl)porphinatoiron(II) compound is utilized in this study to demonstrate solution coordination by chloride, bromide and acetate ions. The binding strength of anions to the iron(II) porphyrin is reflected by a systematic change in pyrrole proton chemical shift in $^1H$ NMR spectra; the pyrrole resonance moves downfield when the ${\sigma}$-donor ability of anions is decreased.

• Bulletin of the Korean Chemical Society
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• v.33 no.8
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• pp.2592-2596
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• 2012

Cysteine capped silver nanoparticles (Cys-AgNPs) have been synthesized by employing electrochemically active biofilm (EAB), $AgNO_3$ as precursor and sodium acetate as electron donor in aqueous solution at $30^{\circ}C$. Cys-AgNPs of 5-10 nm were synthesized and characterized by UV-Vis, FT-IR, XRD and TEM. Capping of the silver nanoparticles with cysteine provides stability to nanoparticles by a thiolate bond between the amino acid and the nanoparticle surface and hydrogen bonding among the Cys-AgNPs. In addition, the antibacterial effects of as-synthesized Cys-AgNPs have been tested against two pathogenic bacteria Escherichia coli (O157:H7) and Pseudomonas aeruginosa (PAO1). The results demonstrate that the as-synthesized Cys-AgNPs can proficiently inhibit the growth and multiplication of E. coli and P. aeruginosa.

• Journal of the Korean Chemical Society
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• v.58 no.3
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• pp.297-302
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• 2014

The synthetic route to coumarin systems is well established and one approach of particular interest leads to the intermediate 7-diethylamino-3-formylcoumarin. A combination of the N,N-diethylamino-coumarin donor with a wide range of acceptor groups of varying electron withdrawing strength should permit the synthesis of a series of extended coumarin dyes with absorption maxima range from 500 to 600 nm, or even beyond. In this communication, a novel efficient synthesis of indoles, benzothiazole and benzoxazole based on coumarin chromophores were achieved and the coloristic and fluorophoric properties of these chromophores were studied.

• Composites Research
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• v.31 no.2
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• pp.76-81
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• 2018

In this study, the elemental mercury removal behaviors of silver-plated porous carbons materials were investigated. The pore structures and total pore volumes of the hybrid materials were analyzed by $N_2$ adsorption/desorption analysis at 77 K. The pore structures and surface morphologies of the hybrid materials were characterized by XRD and SEM, respectively. The elemental mercury adsorption capacities of all silver-plated porous carbons hybrid materials were higher than those of the as-received samples, despite the fact that the specific surface areas and total pore volumes decreased with increasing metal loading time. It was found that silver nanoparticles showed excellent elemental mercury removal behaviors in carbonaceous hybrid materials.

• BMB Reports
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• v.32 no.2
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• pp.168-172
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• 1999

We previously reported that a novel thiol peroxidase (p20) from Escherichia coli is a distinct periplasmic peroxidase that detoxifies hydroperoxides together with glutathione or thioredoxin. Until now, there was no experimental evidence for the presence of thioredoxin (Trx) in the periplasmic space. In an attempt to confirm the physiological function of p20 as a thiol peroxidase supported by Trx in the periplasmic space, we have purified a Trx activity from the periplasmic space of Escherichia coli and identified the Trx as the same protein as the cytoplasmic Trx. The presence of Trx in the periplasmic space of Escherichia coli suggests that p20 is a unique extracellular Trx-linked thiol peroxidase.

• Carbon letters
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• v.12 no.2
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• pp.112-115
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• 2011

The scope of this work investigates the relationship between the amount of oxygen-functional groups and hydrogen adsorption capacity with different concentrations of phosphoric acid. The amount of oxygen-functional groups of activated carbons (ACs) is characterized by X-ray photoelectron spectroscopy. The effects of chemical treatments on the pore structures of ACs are investigated by $N_2$/77 K adsorption isotherms. The hydrogen adsorption capacity is measured by $H_2$ isothermal adsorption at 298 K and 100 bar. In the results, the specific surface area and pore volume slightly decreased with the chemical treatments due to the pore collapsing behaviors, but the hydrogen storage capacity was increased by the oxygen-functional group characteristics of AC surfaces, resulting from enhanced electron acceptor-donor interaction at interfaces.

• BMB Reports
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• v.28 no.3
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• pp.249-253
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• 1995

The nonenzymatic glycation of copper, zinc-superoxide dismutase (Cu,Zn-SOD) led to inactivation and fragmentation of the enzyme. The glycated Cu,zn-SOD was isolated by boronate affinity chromatography. The formation of 8-hydroxy-2'-deoxyguanosine (8-OH-dG) in calf thymus DNA and the generation of strand breaks in pBhiescript plasmid DNA by a metal-catalyzed oxidation (MCO) system composed of $Fe^{3+}$, $O_2$, and glutathione (GSH) as an electron donor was enhanced more effectively by the glycated CU,Zn-SOD than by the nonglycated enzyme. The capacity of glycated Cu,Zn-SOD to enhance damage to DNA was inhibited by diethylenetriaminepentaacetic acid (DETAPAC), azide, mannitol, and catalase. These results indicated that incubation of glycated CU,Zn-SOD with GSH-MCO may result in a release of $Cu^{2+}$ from the enzyme. The released $Cu^{2+}$ then likely participated in a Fenton-type reaction to produce hydroxyl radicals, which may cause the enhancement of DNA damage.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.103-103
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• 2003

ZnO$_{1-x}$(또는 Zn$_{1+x}$O) 산화아연은 과잉의 아연(또는 oxygen vacancy)이 도우너(donor) 역할을 하는 비화학양론적 n형 산화물 반도체이다. ZnO는 높은 투과율을 가지고 온도나 주변환경에 대해 매우 안정하며, 또한 이미 상용화된 ITO (Indium tin oxide)에 비해 식각 특성이 우수하고, 수소 플라즈마에 대한 저항성이 크다는 장점 때문에 가스센서와 디스플레이용 소자 등 다양한 분야에 응용이 가능하다. ZnO 박막은 CVD, Reactive Magnetron Sputtering, Electron-beam Evaporation 등 여러 가지방법으로 제작할 수 있다. 본 연구에서는 형성된 박막의 구성성분이 타겟의 성분과 유사하고 낯은 기판온도에서도 박막이 형성되어지는 장점을 가지는 Pulsed Laser Deposition 방법을 사용하여 유리 기판위에 ZnO 박막을 형성하였다.다.