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Organic-inorganic hybrid photocatalyst for carbon dioxide reduction
Won, D. I.,Lee, J. S.,Cheong, H. Y.,Cho, M.,Jung, W. J.,Son, H. J.,Pac, C.,Kang, S. Royal Society of Chemistry 2017 Faraday discussions Vol.198 No.-
<P>Efficient hybrid photocatalysts for carbon dioxide reduction were developed from dye-sensitized TiO2 nanoparticles and their catalytic performance was optimized by ternary organic/inorganic components. Thus, the hybrid system consists of (E)-2-cyano-3-(5'(5 ''-(p-(diphenylamino)phenyl)thiophen-2 ''-yl)thiophen-2'-yl)-acrylic acid as a sensitizer and fac-[Re(4,4'-bis(diethoxyphosphorylmethyl)-2,2'-bipyridine)(CO)(3)Cl] as a reduction catalyst (ReP), both of which have been fixed onto TiO2 semiconductors (s-TiO2, h-TiO2, d-TiO2). Mott-Schottky analysis on flat-band potential (E-fb) of TiO2 mesoporous films has verified that Efb can be finely modulated by volume variation of water (0 to 20 vol%). The increase of added water resulted in substantial positive shifts of Efb from -1.93 V at 0 vol% H2O, to -1.74 V (3 vol% H2O), to -1.56 V (10 vol% H2O), and to -1.47 V (20 vol% H2O). As a result, with addition of 3-10 vol% water in the photocatalytic reaction, conversion efficiency of CO2 to CO increased significantly reaching a TON value of similar to 350 for 30 h. Catalytic activity enhancement is mainly attributed to (1) the optimum alignment of Efb by 3-10 vol% water with respect to the E-ox* of the dye and E-red of ReP for smooth electron transfer from photo-excited dye to ReP via the TiO2 semiconductor and (2) the water-induced acceleration of chemical processes on the fixed ReP. In addition, the energy level was further tuned by variation of the dye and ReP amounts. We also found that the intrinsic properties of TiO2 sources (morphology, size, agglomeration) exert a great influence on the overall photocatalytic activity of this hybrid system. Implications of the present observations and reaction mechanisms are discussed in detail.</P>
Coordination Compound Molecular Sieve Membranes
Won, J.,Seo, J. S.,Kim, J. H.,Kim, H. S.,Kang, Y. S.,Kim, S.-J.,Kim, Y.,Jegal, J. WILEY-VCH Verlag 2005 ADVANCED MATERIALS Vol.17 No.1
<B>Graphic Abstract</B> <P>Highly selective molecular sieve composite membranes have been prepared using dispersions of porous coordination compounds confined within amorphous glassy polysulfone. This new approach is a promising method for fabricating organic molecular sieve composite membranes with tailor-made structures and pore sizes. The organic molecular sieves exhibit enhanced selectivity for H<SUB>2</SUB> over CH<SUB>4</SUB> (approximately 200 at 5 wt.-% loading). <img src='wiley_img/09359648-2005-17-1-ADMA200400447-content.gif' alt='wiley_img/09359648-2005-17-1-ADMA200400447-content'> </P>
Kim, J.H.,Lee, G.,Cho, Y.L.,Kim, C.K.,Han, S.,Lee, H.,Choi, J.S.,Choe, J.,Won, M.H.,Kwon, Y.G.,Ha, K.S.,Kim, Y.M. North-Holland ; Elsevier Science Ltd 2009 european journal of pharmacology Vol.602 No.2
We investigated the effect of desmethylanhydroicaritin (DMAI), a major compound of the Chinese herbal medicine Epimedium, on inflammatory gene expression and the NF-κB signaling pathway. We found that DMAI suppressed the expression of NF-κB-responsive genes, such as inducible nitric oxide synthase, cyclooxygenase-2, interleukin-1β, and tumor necrosis factor-α, in lipopolysaccharide (LPS)-stimulated macrophages and endotoxemic mice as well as protected mice against LPS-induced lethality. DMAI inhibited NF-κB activation through the inhibition of IκB kinase (IKK) activation, IκB phosphorylation and degradation, and NF-κB nuclear translocation in LPS-stimulated macrophages. This compound inhibited in vitro and in vivo LPS-induced phosphatidylinositol 3-kinase (PI3K) activation, phosphatase and tensin homolog deleted on chromosome 10 (PTEN) oxidation, and Akt phosphorylation, which are upstream modulators of IKK activation. Moreover, treatment with DMAI was not observed to affect the interaction between the Toll-like receptor 4, MyD88, and TRAF6 as well as mitogen-activated protein kinase activation. DMAI also suppressed intracellular H<SUB>2</SUB>O<SUB>2</SUB> accumulation, hydroxyl radical production, and glutathione oxidation without affecting superoxide generation and accumulation by NADPH oxidase. Moreover, DMAI inhibited redox-sensitive activation of the PI3K/PTEN/Akt pathway and NF-κB activation in macrophages treated with H<SUB>2</SUB>O<SUB>2</SUB>. These results indicate that DMAI negatively regulates canonical NF-κB-regulated inflammatory gene expression by functioning as an inhibitor of the NF-κB pathway through the suppression of redox-based PI3K activation and PTEN inactivation and therefore can be considered as a potential drug for inflammatory diseases.
Lee, J.W.,Kang, H.M.,Won, E.J.,Hwang, D.S.,Kim, D.H.,Lee, S.J.,Lee, J.S. Elsevier/North Holland Biomedical Press 2016 Aquatic toxicology Vol.172 No.-
<P>To examine the toxic effects of multi-walled carbon nanotubes (MWCNTs) in the marine environment, we first exposed the monogonont rotifer (Brachionus koreanus) to MWCNTs in the presence of copper. The acute toxicity of copper decreased significantly with a decrease in copper bioavailability resulting from MWCNT exposure. Furthermore, we examined the effects of MWCNT exposure on reproductive capacity, population growth rate, growth patterns, antioxidant systems, and mitogen-activated protein kinase (MAPK) activation. Reproductive capacity, population growth rate, and body growth rate were significantly suppressed in B. koreanus in response to 13-4 mg/L MWCNT exposure. Furthermore, MWCNT5 induced the generation of reactive oxygen species (ROS) and decreased the antioxidant enzymatic activities of catalase (CAT) and glutathione reductase (GR). However, the enzymatic activity of glutathione S-transferase (GST) was up-regulated after a 24 h-exposure to 100 mg/L MWCNT5. Exposure to 100 mg/L MCWNTs induced extracellular signal-regulated kinase (ERK) activation in B. koreanus, suggesting that p-ERK may mediate the adverse effects of MWCNTs in B. koreanus via the MAPK signaling pathway. Our results provide insight into the mechanistic basis of the ecotoxicological effects of MWCNTs in the marine environment. (C) 2015 Elsevier B.V. All rights reserved.</P>
Sol-Gel 법에 의한 Al2O3 제조시 침전제 (H2C2O4) 의 영향
오재현,원창환,천병선,이정원 대한금속재료학회(대한금속학회) 1991 대한금속·재료학회지 Vol.29 No.1
A new way of producing alumina from the alkoxide is reported. Aluminum oxalate is first synthesized by reactions which allow controlled precipitation. Alumina powder is obtained by subsequent thermal decomposition. 1) The addition of H₂C₂O₄, in the Boehmite Sol. was able to reduce the Geling time. 2) The first generated particles in the size of 10㎛ were agglomerated in chain type. 3) The recovery of A1₂O₃ was increased with increasing PH of solution and decreasing both the mole ratio of H₂C₂O₄/ Alkoxide and reaction temperature. 4) The grain size of the calcined products was increased with increasing PH of solution, mole ratio of H₂C₂O₄/ Alkoxide and reaction temperature, however, decreased significantly in the range of PH 1.