Topic
Redox
About: Redox is a research topic. Over the lifetime, 26853 publications have been published within this topic receiving 862368 citations. The topic is also known as: reduction-oxidation & reduction-oxidation reaction.
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283 citations
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TL;DR: The concept on the mode of action of Cu(II) and Cu(I) ions in lipid peroxidation as presented here suggests the influence of Cu on different reactions.
Abstract: The phytotoxic effect of Cu via the photosynthetic electron transport system was studied with isolated spinach chloroplasts. Cu(II) ions induce a light-driven peroxidation of membrane lipids leading to ethylene formation, the latter dominating over a concurrent ethane production. Seemingly, the hydroxyl radical originating from superoxide anion is the starting reactive O2 species. Cu ions inhibit photosynthetic electron transport and apparently catalyze the formation of hydroxyl radical and Fenton-type reactions that result in destruction of unsaturated membrane fatty acids. The concept on the mode of action of Cu(II) and Cu(I) ions in lipid peroxidation as presented here suggests the influence of Cu on different reactions. Two sites are in the photosynthetic redox system; Cu participates in two Fenton-type reactions and in the conversion of ethyl radical to ethylene and ethane.
283 citations
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TL;DR: This work describes highly reversible aqueous ZIBs based on layered VOPO4 cathodes and a water-in-salt electrolyte that display reversible oxygen redox chemistry in a high-voltage region and promotes the reversible crystal-structure evolution of VopO4 during charge/discharge processes, resulting in enhanced rate capability and cycling performance.
Abstract: Rechargeable aqueous zinc-ion batteries (ZIBs) are promising energy-storage devices owing to their low cost and high safety. However, their energy-storage mechanisms are complex and not well established. Recent energy-storage mechanisms of ZIBs usually depend on cationic redox processes. Anionic redox processes have not been observed owing to the limitations of cathodes and electrolytes. Herein, we describe highly reversible aqueous ZIBs based on layered VOPO4 cathodes and a water-in-salt electrolyte. Such batteries display reversible oxygen redox chemistry in a high-voltage region. The oxygen redox process not only provides about 27 % additional capacity, but also increases the average operating voltage to around 1.56 V, thus increasing the energy density by approximately 36 %. Furthermore, the oxygen redox process promotes the reversible crystal-structure evolution of VOPO4 during charge/discharge processes, thus resulting in enhanced rate capability and cycling performance.
283 citations
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TL;DR: It appears that redox-inert zinc has been chosen to control some aspects of cellular thiol/disulfide redox metabolism.
Abstract: Zinc/cysteine coordination environments in proteins are redox-active. Oxidation of the sulfur ligands mobilizes zinc, while reduction of the oxidized ligands enhances zinc binding, providing redox control over the availability of zinc ions. Some zinc proteins are redox sensors, in which zinc release is coupled to conformational changes that control varied functions such as enzymatic activity, binding interactions, and molecular chaperone activity. Whereas the released zinc ion in redox sensors has no known function, the redox signal is transduced to specific and sensitive zinc signals in redox transducers. Released zinc can bind to sites on other proteins and modulate signal transduction, generation of metabolic energy, mitochondrial function, and gene expression. The paradigm of such redox transducers is the zinc protein metallothionein, which, together with its apoprotein, thionein, functions at a central node in cellular signaling by redistributing cellular zinc, presiding over the availability of zinc, and interconverting redox and zinc signals. In this regard, the transduction of nitric oxide (NO) signals into zinc signals by metallothionein has received particular attention. It appears that redox-inert zinc has been chosen to control some aspects of cellular thiol/disulfide redox metabolism. Tight control of zinc is essential for redox homeostasis because both increases and decreases of cellular zinc elicit oxidative stress. Depending on its availability, zinc can be cytoprotective as a pro-antioxidant or cytotoxic as a pro-oxidant. Any condition with acute or chronic oxidative stress is expected to perturb zinc homeostasis.
282 citations
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TL;DR: In this paper, the authors studied the sequence of reduction of three electron acceptors under controlled redox potential conditions, and showed that the oxidation and reduction of these three electronacceptors were sequential, with no overlap in the oxidation or reduction of the NO3 and Mn systems and little overlap in oxidation and reducing of the Mn and Fe compounds.
Abstract: When a soil is flooded, the curtailment of O2 diffusion into the soil causes the microorganisms decomposing organic matter to switch from O2 to alternate electron acceptors. Three alternates utilized by facultative microorganisms when O2 becomes depleted are NO3 , Mn compounds, and Fe compounds. We studied the sequence of reduction of these three redox systems under controlled redox potential conditions. The redox potential of soil suspensions was changed stepwise in 50-mV increments from oxidized to reduced conditions and from reduced to oxidized conditions and maintained at each new potential for 15 d, at which time NO3, NH4, Mn, and Fe concentrations in the soil solution were analyzed. The results of this study showed that the oxidation and reduction of the three electron acceptors were sequential, with no overlap in the oxidation or reduction of the NO3 and Mn systems and little overlap in oxidation and reduction of the Mn and Fe systems. In the oxidized-to-reduced experiment, the critical redox potential at which all of the NO3was reduced and Mn first appeared in the soil solution was approximately 200 mV. The critical redox potential at which Fe appeared was 100 mV. For all three redox systems, the critical redox potentials for the oxidized-toreduced transition were approximately 50 mV lower than for the reduced-to-oxidized transition. View complete article To view this complete article, insert Disc 5 then click button8
282 citations