• 대한화학회지
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• 제41권5호
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• pp.246-250
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• 1997

히드록실아민이 존재하는 붕산염 매질에서 루테늄(III)은 수은 표면에 사전농축이 잘 되었고 이 피흡착질의 환원 생성물에 의한 촉매 수소 전류를 측정함으로써 혼적량 루테늄을 정량할 수 있었다. 순환 전압전류법으로 산화환원 및 흡착 누적 특성을 조사하였다. 최적 조건은 다음과 같다: 붕산염 0.015 M, pH 2,5, 히드록실아민 0.55 M, 누적 전위 -0.70 V, 그리고 시차 펄스 모드에서 주사속도 5 mV/s이었다. 이 조건에서 검출한계는 $3{\times}10^{-10}$(7분 수집)이었다. 방해 가능한 다른 백금족 금속이온들의 허용량도 조사하였다.

• Current Research on Agriculture and Life Sciences
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• 제32권1호
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• pp.43-52
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• 2014

Reactive oxygen and nitrogen species (ROS and RNS, respectively) are messengers that carry signals to alter the redox state in order to activate plant responses and other physiological processes, such as differentiation, aging, senescence, and pathogen defense. Quite a large number of genes are involved in this signaling and lead to oxidative stress in plants. Although the role of ROS/RNS during stress conditions is well documented, a comprehensive list of genes and comparative study of these genes has not yet been completed. Accordingly, the in silico identification of oxidative stress-related genes was performed for soybeans and Arabidopsis. These genes were also studied in relation to multiple domain prediction. The presence of domains like dehydogenase and ATPase suggests that these genes are involved in various metabolic processes, as well as the transportation of ions under optimal environmental conditions. In addition to a sequence analysis, a phylogenetic analysis was also performed to identify orthologous pairs among the soybean and Arabidopsis oxidative stress-related genes based on neighbor joining. This study was also conducted with the objective of further understanding the complex molecular signaling mechanism in plants under various stress conditions.

• Asian Pacific Journal of Cancer Prevention
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• 제15권12호
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• pp.4745-4751
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• 2014

Oxidative stress is caused by an imbalance in the redox status of the body. In such a state, increase of free radicals in the body can lead to tissue damage. One of the most important species of free radicals is reactive oxygen species (ROS) produced by various metabolic pathways, including aerobic metabolism in the mitochondrial respiratory chain. It plays a critical role in the initiation and progression of various types of cancers. ROS affects different signaling pathways, including growth factors and mitogenic pathways, and controls many cellular processes, including cell proliferation, and thus stimulates the uncontrolled growth of cells which encourages the development of tumors and begins the process of carcinogenesis. Increased oxidative stress caused by reactive species can reduce the body's antioxidant defense against angiogenesis and metastasis in cancer cells. These processes are main factors in the development of cancer. Bimolecular reactions cause free radicals in which create such compounds as malondialdehyde (MDA) and hydroxyguanosine. These substances can be used as indicators of cancer. In this review, free radicals as oxidizing agents, antioxidants as the immune system, and the role of oxidative stress in cancer, particularly breast cancer, have been investigated in the hope that better identification of the factors involved in the occurrence and spread of cancer will improve the identification of treatment goals.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 총회 및 춘계학술발표회
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• pp.179-182
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• 2002

The objective of this study was to evaluate petroleum hydrocarbon degradation processes governing natural attenuation at tile contaminated site and accomplished through conducting on investigation of degradation rate, capacity, and mechanism of the monitored natural attenuation. The monitoring results of the three years indicated that the concentrations of DO, nitrate, and sulfate in the contaminated area were significantly lower than these in the none-contaminated area. The results also showed a higher ferrous iron concentration, a lower redox potential and a neutral pH in the contaminated groundwater, suggesting that biodegradation of TEX is the major on-going process in the contaminated area. However, reduction of TEX in the groundwater was not only biodegradation but also dilution and reaeration during infiltration of uncotaminated surface and groudwater.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.318-322
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• 2004

Arsenic is a toxic and carcinogenic metalloid, whose sources in nature include mineral dissolution and volcanic eruption. Abandoned mines and hazardous waste disposal sites are another major source of arsenic contamination of soil and aquatic systems. To predict concentrations of the toxic inorganic arsenic in aqueous phase. the biogeochemical redox processes and transport behavior need to be studied together and be coupled in a reactive transport model. A new reaction module describing the fate and transport of inorganic arsenic species (As(II)), dissolved oxygen, nitrate, ferrous iron, sulfate, and dissolved organic carbon are developed and incorporated into the RT3D code.

• 한국염색가공학회지
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• 제17권4호
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• pp.1-6
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• 2005

We studied the degree of variety of indigo for the electrochemical redox reaction in addition of reducing agent and the electrokinetic parameters. The electrokinetic parameters such asthe number of electron and the exchange rate constant were obtained by cyclic voltammetry. With increasing scan rate, the reduction currents of indigo were increased and the reduction potentials were shifted to the negative direction. As the results, the reduction processes of the indigo were proceeding to totally irreversible and diffusion controlled reaction. Also, exchange rate constant ($k^0$) and diffusion coefficient ($D_0$) of indigo were decreased by increasing concentration of reducing agent. We found that the less concentration, the more easily diffused and electron transferred and the product was more stable.

• 한국미생물·생명공학회지
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• 제31권2호
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• pp.197-200
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• 2003

In oil-contaminated environments, anaerobic biodegradation of toluene depended on the concentration and distribution of terminal electron acceptor as well as the physicochemical properties such as DO concentration, redox potential and pH. This study showed the anaerobic biodegradation of toluene in two different soils by using nitrate reduction, ferric iron reduction, sulfate reduction and methanogensis. Toluene degradation rates in the soil samples taken from rice filed and tidal mud flat by nitrate reduction were higher than those by other processes. Tho soil samples from the two fields were enriched for 130 days by providing toluene as a sole carbon source and nitrate or sulfate as a terminal electron acceptor. The toluene degradation rates in the enriched denitrifying consortia obtained from the rice field and tidal mud flat soil were 310.7 and 200.6 $\mu$mol$ L^{-1}$ / $d^{-1}$, respectively. The toluene (legradation rates in the enriched sulfate-reducing consortia from the fields ranged fi-om 149.1 to 86.1$\mu$mol $L^{-1}$ / $d^{-1}$ .

• The Korean Journal of Physiology and Pharmacology
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• 제7권5호
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• pp.275-278
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• 2003

Antioxidative activity is an important factor in inhibiting oxidative stress. The usual methods for determining antioxidative activity are time-consuming and cumbersome. They are also indirect processes that use biological material such as brain or liver microsome. This study therefore proposed a new method. Redoxpotential was determined using galvanic cell with or without the addition of various antioxidants or herbal extracts in zinc sulfate solution. The result was compared with the results from the TBA method and the peroxide value from sodium thiosulfate titration. All methods showed significant and dose-dependent enhancement of antioxidative activity by adding ascorbic acid, quercetin, ginseng, or gingko biloba extract. The result of redox potential using galvanic cell showed the smallest standard deviation and took the shortest time among the three methods. Therefore, the antioxidative potential of chemical substances and herbal extracts can be determined simply, directly and accurately in a short period of time using galvanic cell.

• Bulletin of the Korean Chemical Society
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• 제13권3호
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• pp.259-265
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• 1992

Cyclic voltammetric behavior of symmetric (dimethyl, diheptyl, dioctyl, dibenzyl) and asymmetric (methyloctyl, methyldodecyl, methylbenzyl) viologens was investigated in homogeneous aqueous solution and sodium dodecyl sulfate (SDS) micellar media. In SDS-free 0.1 M NaCl solutions, the reduction potential is less negative as the chain length of alkyl substituent is longer. This is due to the stabilization of the reduced cationic radical and neutral form of viologen by adsorption on electrode surface. The adsorbed species show the "aging-effect". With the exceptions of methyldodecyl viologen and methylbenzyl viologen, the viologens show strong tendency of conproportionation reaction between viologen dications and neutral forms. In cases of methyldodecyl viologen and methylbenzyl viologen, the conproportionation reaction is kinetically disfavored, though it is thermodynamically favorable. SDS micelles dissolve the adsorbed species and the viologens exhibit two reversible redox processes in SDS micellar solutions. The reduction potentials of viologens in SDS micellar solutions depend little on the length of alkyl chain. Benzyl-substituted viologens are more easily reduced than the alkyl substituted viologens, presumably due to electron-withdrawing character of benzyl group.

• 자연과학논문집
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• 제17권1호
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• pp.13-29
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• 2006

산화-환원 활성 단백질중에 하나인 설피레독신과의 결합 단백질을 효모 Two-hybrid 기법을 이용하여 탐색한 결과, 알파-만노시다제가 설피레독신과 특이적으로 결합함을 밝혔다. 알파-만노시다제는 D-만노스 당을 비환원성 말단으로부터 유리시키는 가수분해 효소로서, 세포 원형질에 다량체 형태로 존재한다. 본 연구에서는 설피레독신과 알파-만노시다제간의 단백질결합을 설피레독신의 새로운 생리기능 관점에서 토의했다.