• Title/Summary/Keyword: oxidation/reduction potential

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Electrochemical behaviors of Indium

  • Chung, Yong-Hwa;Lee, Chi-Woo
    • Journal of Electrochemical Science and Technology
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    • v.3 no.1
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    • pp.1-13
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    • 2012
  • Many researchers focus on indium contained semiconductors and alloy compounds for their various applications. Electrochemists want to obtain indium contained compounds simply via one-step electrodeposition. First of all, electrochemistry of constituent elements must be understood in order to develop the best condition for the electrodeposition of indium contained compounds. We will review the electrochemistry of indium. Equilibria between indium metal and indium ions and the standard electrode potentials of the equilibria will be reviewed. The electrochemical reactions of indium species are affected by surrounding conditions. Thus dependences of electrochemical behaviors of indium metal and indium ions on various parameters will be reviewed.

Investigation of the Water Gas Shift from Reforming Gas for CO Removal (일산화탄소 저감을 위한 개질가스의 전이반응 연구)

  • Kim, Seong-Cheon;Youn, Moon-Jung;Chun, Young-Nam
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.10
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    • pp.855-859
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    • 2007
  • Hydrogen as an energy carrier in fuel cell offers perhaps the largest potential benefits of reduced emissions of pollutants and greenhouse gases. The generation of high-purity hydrogen from hydrocarbon fuels is essential for efficient operation of fuel cell. Reduction of carbon monoxide to an acceptable level of 10ppm involves high temperature and low temperature water gas shift (WGS), followed by selective oxidation of residual carbon monoxide. The WGS reactor was designed and tested in this study to produce hydrogen-rich gas with CO to less than 5000 ppm. In the water gas shift operation, gas emerges from the reformer is taken through a high temperature shift (HTS) catalyst to reduce the CO concentration to about $2{\sim}4%$ followed to about 5000 ppm via a low temperature shift (LTS) catalyst.

Action of Asparagus racemosus Against Streptozotocin-Induced Oxidative Stress

  • Govindarajan, Raghavan;Vijayakumar, Madhavan;Rao, Chandana Venkateshwara;Kumar, Vivek;Rawat, Ajay Kumar Singh;Pushpangadan, Palpu
    • Natural Product Sciences
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    • v.10 no.4
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    • pp.177-181
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    • 2004
  • Antidiabetic treatment with tubers of Asparagus racemosus (Liliaceae) extract (l00 and 250 mg/kg body weight) for three weeks showed significant reduction in thiobarbituric acid reactive substances (TBARS) and glutathione reductase (GSH-R) in both liver and kidney. The treatment with A. racemosus significantly altered the glutathione (GSH) and GSH-R to be comparable with the control group. A. racemosus and glibenclamide treated rats showed decreased lipid peroxidation that is associated with increased activity of superoxide dismutase (SOD) and Catalase (CAT). The ability of A. racemosus on tissue lipid per oxidation and antioxidant status in diabetic animals has not been studied before. The result of this study thus shows that though, A. racemosus possesses moderate antidiabetic activity, but it exhibits potent antioxidant potential in diabetic conditions.

Simple and Ultrasensitive Chemically Amplified Electrochemical Detection of Ferrocenemethanol on 4-Nitrophenyl Grafted Glassy Carbon Electrode

  • Koh, Ahyeon;Lee, Junghyun;Song, Jieun;Shin, Woonsup
    • Journal of Electrochemical Science and Technology
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    • v.7 no.4
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    • pp.286-292
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    • 2016
  • Chemically amplified electrochemical detection, redox-active probe being amplified its electrochemical anodic current by a sacrificial electron donor presenting in solution, holds great potential for simple and quantitative bioanalytical analysis. Herein, we report the chemically amplified electrochemical analysis that drastically enhanced a detection of ferrocenemethanol (analyte) by ferrocyanide (chemical amplifier) on 4-nitrophenyl grafted glassy carbon electrodes at $60^{\circ}C$. The glassy carbon electrode grafted with a 4-nitrophenyl group using an electrochemical reduction suppressed the oxidation of ferrocyanide and thus enabled detection of ferrocenemethanol with excellent selectivity. The ferrocenemethanol was detected down to an nM range using a linear sweep voltammetry under kinetically optimized conditions. The detection limit was improved by decreasing the concentration of the ferrocyanide and increasing temperature.

AC Impedance Study of the Electrochemical Behavior of Hydrogen/Oxygen Gas Mixture at Nafion/Catalyst Electrode Interface

  • Song, S.M.;Lee, W.M.
    • Journal of Hydrogen and New Energy
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    • v.11 no.4
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    • pp.179-188
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    • 2000
  • The anodic reaction of hydrogen/oxygen gas mixture at platinum or palladium electrode interfacing with a solid polymer electrolyte was investigated using AC impedance method. The impedance spectrum of the electrode reactions of the mixture depends on the gas composition, electrode roughness, the mode of electrochemical operation and the cell potential. For electrolysis mode of operation, the spectrum taken for the reaction on a rough platinum electrode for the gas mixture revealed clearly that the local anodic reduction of oxygen gas takes place concurrently with the anodic oxidation of hydrogen gas.

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Real-time Chemical Monitoring System using RGB Sensor toward PCB Manufacturing (PCB 제조공정을 위한 화학약품 용액의 실시간 모니터링 시스템)

  • An, Jong-Hwan;Lee, Seok-Jun;Kim, Lee-Chui;Hong, Sang-Jeen
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.21 no.5
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    • pp.397-401
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    • 2008
  • Most of the topic in PCB industry was about increasing the volume of product for the development of electronics in numerous industrial application area. However, it has been emerged that yield improvement quality manufacturing via detecting any suspicious process in order to minimize the scrapped product and material waste. In addition, recently, restriction of hazardous substances (RoHS) claims that electronic manufacturing environment should reduce the harmful chemicals usage, thus the importance of monitoring copper etchant and detecting any mis-processing is crucial for electronics manufacturing. In this paper, we have developed real-time chemical monitoring system using RGB sensor, which is simpler but more accurate method than commercially utilized oxidation reduction potential (ORP) technique. The developed Cu etchant monitoring system can further be utilized for copper interconnect process in future nano-semiconductor process.

Characterization of in vitro Metabolites of Methylenedioxy Designer Drugs

  • Jun Sang Yu;So Young Jo;Il-Ho Park;Hye Hyun Yoo
    • Mass Spectrometry Letters
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    • v.14 no.1
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    • pp.1-8
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    • 2023
  • Eutylone, dibutylone, and dimethylone are potential psychotropic designer drugs. The purpose of this study was to investigate the in vitro metabolic pathways of synthetic cathinones with methylenedioxy groups. The three methylenedioxy derivatives were incubated with human liver microsomes. The metabolites were characterized based on liquid chromatography and quadrupole-time-of-flight mass spectrometry. Eutylone, dibutylone, and dimethylone were metabolized to yield three, six, and four metabolites, respectively. Reduction and demethylenation were the major metabolic pathways for all three drugs tested. However, dibutylone and dimethylone showed an additional metabolite generated via N-oxidation. These results provide evidence for the in vivo metabolism of methylenedioxy synthetic cathinones, and could be applied to the analysis of synthetic cathinones and their relevant metabolites in biological samples.

Computational approaches for molecular characterization and structure-based functional elucidation of a hypothetical protein from Mycobacterium tuberculosis

  • Abu Saim Mohammad, Saikat
    • Genomics & Informatics
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    • v.21 no.2
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    • pp.25.1-25.12
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    • 2023
  • Adaptation of infections and hosts has resulted in several metabolic mechanisms adopted by intracellular pathogens to combat the defense responses and the lack of fuel during infection. Human tuberculosis caused by Mycobacterium tuberculosis (MTB) is the world's first cause of mortality tied to a single disease. This study aims to characterize and anticipate potential antigen characteristics for promising vaccine candidates for the hypothetical protein of MTB through computational strategies. The protein is associated with the catalyzation of dithiol oxidation and/or disulfide reduction because of the protein's anticipated disulfide oxidoreductase properties. This investigation analyzed the protein's physicochemical characteristics, protein-protein interactions, subcellular locations, anticipated active sites, secondary and tertiary structures, allergenicity, antigenicity, and toxicity properties. The protein has significant active amino acid residues with no allergenicity, elevated antigenicity, and no toxicity.

Synthesis of Neplanocin A Analog with 2′-“up”-C-Methyl Substituent as Potential Anti-HCV Agent

  • Lee, Hyung-Rock;Kang, Jin-Ah;Park, Ah-Young;Kim, Won-Hee;Chun, Pu-Soon;Kim, Jung-Su;Kim, Jin-Ah;Lee, Bo-Eun;Jeong, Lak-Shin;Moon, Hyung-Ryong
    • Bulletin of the Korean Chemical Society
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    • v.30 no.9
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    • pp.2043-2050
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    • 2009
  • 2′-$\beta$-C-Methylneplanocin A (3) was synthesized via 2-$\beta$-C-methylribonolactone, prepared by a modified Whistler and BeMiller’s method developed by our laboratory, as potential anti-HCV agent. Reduction of 14 with Dibal-H afforded 26 in a good yield with a trace of 25, whereas a Luche reduction gave 26/25 = 4/1 mixture. Several attempts were made to chemoselectively remove TBS group in the presence of TBDPS group and treatment with both PPTS and TsOH showed the best result. Condensation of 26 with 6-chloropurine under Mitsunobu conditions produced an $S_N$2 product 27 along with an $S_N$2′ product 28.

Voltammetric Studies on Some Thiadiazoles and Their Derivatives

  • Maghraby, A. A. El;Abou-Elenien, G. M.;Rateb, N. M;Abdel-Tawab, H. R.
    • Journal of the Korean Electrochemical Society
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    • v.12 no.1
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    • pp.54-60
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    • 2009
  • The redox characteristics of 2-arylaldehydehydrazono-3-phenyl-5-substituted-2, 3-dihydro-1, 3, 4-thiadiazoles (1a-h) have been investigated in nonaqueous solvents such as 1, 2-dichloroethane (DCE), dichloromethane (DCM), acetonitrile (AN), Tetrahydrofuran (THF), and dimethylsulfoxide (DMSO) at platinum electrode. Through controlled potential electrolysis, the oxidation and reduction products of the investigated compounds had been separated and indentified. The redox mechanism had been suggested and proved. It had been found that all the investigated compounds were oxidized in two irreversible one-electron processes following the well-known pattern of The EC-mechanism; the first electron loss gives the corresponding cation-radical which is followed by proton removal from the ortho-position in the N-phenyl ring forming the radical. The obtained radical undergoes a second electron uptake from the nitrogen in the N = C group forming the unstable intermediate (di-radical cation) which undergoes ring closure forming the corresponding cation. The formed cation was stabilized in solution through its combination with a perchlorate anion from the medium. On the other hand, these compounds are reduced in a single two-electron process or in a successive two one-electron processes following the well known pattern of the EEC-mechanism according to the nature of the substituent; the first one gives the anion-radical followed by a second electron reduction to give the dianion which is basic enough to abstract protons from the media to saturate the (C = O) bond.