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This resource was assembled for the primary purpose of serving the research needs of students and investigators in the field of redox biology. Redox biology is wide-ranging and complex and can present significant challenges to investigators seeking to address research questions in biological systems. Our goal is provide information on the basic principles of redox biology and links to important research resources. For example, a page is devoted to reactive oxygen species highlighting the chemical properties and methods of detection for different reactive oxygen species. In addition, functional and structural information is provided for key redox enzymes/proteins as well as properties of redox metals. Links to various bioinformatics tools are also available which allow researchers to search for selenoproteins, metal binding proteins, redox active cysteines, and glutathionylation sites in proteins. Finally, we have a page devoted to advances in redox medicine with a primary focus on cancer, ...
Publication Advanced Oxidation Processes for Water Treatment: Fundamentals and Applications. Advanced Oxidation Processes (AOPs)that rely on the efficient ...
We developed camptothecin (CPT)-conjugated, core-cross-linked (CCL) micelles that are subject to redox-responsive cleavage of the built-in disulfide bonds, resulting in disruption of the micellar structure and rapid release of CPT. CCL micelles were prepared via coprecipitation of disulfide-containing CPT-poly(tyrosine(alkynyl)-OCA) conjugate and monomethoxy poly(ethylene glycol)-b-poly(tyrosine(alkynyl)-OCA), followed by cross-linking of the micellar core via azide-alkyne click chemistry. CCL micelles exhibited excellent stability under physiological conditions, while they underwent rapid dissociation in reduction circumstance, resulting in burst release of CPT. These redox-responsive CCL micelles showed enhanced cytotoxicity against human breast cancer cells in vitro. Wang, Hua; Tang, Li; Tu, Chunlai; Song, Ziyuan; Yin, Qian; Yin, Lichen; Zhang, Zhonghai; Cheng, Jianjun
Chapter 4: Oxidation - Reduction Reactions. Oxidation - Reduction Reactions involve the gain and loss of electrons. The species involved in these reactions may be atoms, molecules,or ions. Cation : a positively charged ion. (More protons than electrons.) Slideshow 807033 by valterra
The heart relies predominantly on a balance between fatty acids and glucose to generate its energy supply. There is an important interaction between the metabolic pathways of these two substrates in the heart. When circulating levels of fatty acids are high, fatty acid oxidation can dominate over glucose oxidation as a source of energy through feedback inhibition of the glucose oxidation pathway. Following an ischaemic episode, fatty acid oxidation rates increase further, resulting in an uncoupling between glycolysis and glucose oxidation. This uncoupling results in an increased proton production, which worsens ischaemic damage. Since high rates of fatty acid oxidation can contribute to ischaemic damage by inhibiting glucose oxidation, it is important to maintain proper control of fatty acid oxidation both during and following ischaemia. An important molecule that controls myocardial fatty acid oxidation is malonyl-CoA, which inhibits uptake of fatty acids into the mitochondria. The levels of ...
Oxidation & reduction MCQ quiz, oxidation & reduction multiple choice questions answers, online chemistry quiz MCQs old paintings can be restored through oxidizing agent with answers.
Surfactant Enhanced In-situ Chemical Oxidation by VeruTEK Technologies, Inc.. VeruTEK’s patented S-ISCO (Surfactant Enhanced In-situ Chemical Oxidation) process incorporates VeruSOL, a biodegradable, plant-based surfactant/co-solvent mixture th...
Conventional and nanostructured YSZ coatings were deposited on the IN-738 Ni super alloy by the atmospheric plasma spray technique. The oxidation was measured at 1100°C in an atmospheric electrical furnace. According to the experimental results the nanostructured coatings showed a better oxidation resistance than the conventional ones. The improved oxidation resistance of the nanocoating could be explained by the change in structure to a dense and more packed structure in this coating. The mechanical properties of the coatings were tested using the thermal cyclic, nanoindentation and bond strength tests, during which the nanostructured YSZ coating showed a better performance by structural stability.
The importance of oxidation-reduction reactions was recognized from the beginning of chemistry. In oxidation-reduction, some entity is given or taken between two reacting chemicals. The situation is similar to that in acid-base reactions. In brief, oxidation-reduction and acid-base reactions form a pair of systems in chemistry. Oxidation-reduction and acid-base reactions share a common feature in that both had been put into practice before the nature of the reactions was clarified. Important concepts have gradually been developed: for example, the oxidation number, an oxidant (an oxidizing agent), a reductant (a reducing agent), electromotive force, Nernsts equation, Faradays law of electromagnetic induction, and electrolysis. The development of electric cells was significant. Assembling the components of an oxidation-reduction reaction is good practice and a satisfying intellectual challenge. Cells and electrolysis are two particularly important examples because both are strongly related to everyday
Ellibs Ebookstore - Ebook: Photochemical Purification of Water and Air: Advanced Oxidation Processes (AOPs): Principles, Reaction Mechanisms, Reactor Concepts - Author: Oppenländer, Thomas - Price: 151,80€
Chapter 5 Oxidation Reduction Reactions Chemistry: The Molecular Nature of Matter, 7E Jespersen/Hyslop Chapter in Context Define oxidation, reduction, oxidizing agents, reducing agents, and oxidation numbers
Volume 33: Future Vision of Advanced Oxidation Process and its Immediate Efficacy - A Deep, Insightful Comprehension and a Far-Reaching Review
|p|We investigate the influence of the thermal annealing process on the transport properties of thin films made of graphene oxide. Specially developed methodology allows us to demonstrate that the thermal annealing process of graphene oxide thin films can be described as a kinetic process with one activation energy, which equals0.94eV ± 0.12eV. Moreover, we show that the electrical transport mechanism evolves with the annealing temperature (reduction level) of GO thin films. We have noticed that the Variable Range Hopping transport model change from 3D, 2D to Efros-Shklvoskii with a reduction level. Our findings contribute to further understanding of the role of kinetics in thermal reduction processes of thin films made of graphene oxide and could be useful in applications in which electrical parameters need to be tuned.|/p|
Patchy occurrences of elevated As are often encountered in groundwater from the shallow aquifers (,50 m) of the Bengal Delta Plain (BDP). A clear understanding of various biogeochemical processes, responsible for As mobilization, is very important to explain this patchy occurrence and thus to mitigate the problem. The present study deals with the periodical monitoring of groundwater quality of five nested piezometeric wells between December 2008 and July 2009 to investigate the temporal changes in groundwater chemistry vis-a-vis the prevalent redox processes in the aquifer. Geochemical modeling has been carried out to identify key phases present in groundwater. A correlation study among different aqueous redox parameters has also been performed to evaluate prevailing redox processes in the aquifer. The long term monitoring of hydrochemical parameters in the multilevel wells together with hydrogeochemical equilibrium modeling has shown more subtle differences in the geochemical environment of the ...
ATP-hydrolysis and proton pumping by the V-ATPase (vacuolar proton-translocating ATPase) are subject to redox regulation in mammals, yeast and plants. Oxidative inhibition of the V-ATPase is ascribed to disulfide-bond formation between conserved cysteine residues at the catalytic site of subunit A. Subunits containing amino acid substitutions of one of three conserved cysteine residues of VHA-A were expressed in a vha-A null mutant background in Arabidopsis. In vitro activity measurements revealed a complete absence of oxidative inhibition in the transgenic line expressing VHA-A C256S, confirming that Cys256 is necessary for redox regulation. In contrast, oxidative inhibition was unaffected in plants expressing VHA-A C279S and VHA-A C535S, indicating that disulfide bridges involving these cysteine residues are not essential for oxidative inhibition. In vivo data suggest that oxidative inhibition might not represent a general regulatory mechanism in plants. ...
Locate Oxidation Reduction Potential (ORP) Electrodes suppliers, manufacturers & distributors in District of Columbia. Interactive map of District of Columbia provided.
Locate Oxidation Reduction Potential (ORP) Instruments suppliers, manufacturers & distributors in California. Interactive map of California provided.
2 Sheets-Sheet 1 w. L. HENDERSON I CATALYTIC OXIDATION UNIT FOR DOMESTIC OVEN EXHAUST Oct. 27,1970 Filed Feb WAYNE L. HENDERSON ms ATTORNEY Oct. 27 41970 w, HENDERSON 3,536,?!- CATALYTIC OXIDATION UNIT FOR DOMESTIC-OVENBXIIAUST Filed Feb. 21, 1968 2 shms snm a was I FIG.4 . l I I l I I I I I I I I I o 5 l 3o 4o so 6o INVENTOIL WAYNE L. neuoaasou HIS ATTORNEY United States Patent US. Cl. 23-288 2 Claims ABSTRACT OF THE DISCLOSURE A catalytic oxidation unit useful in eliminating smoke and odors issuing from the exhaust vent of a domestic cooking oven, particularly a high temperature, selfcleaning oven using a pyrolytic process for degrading food soils. The oxidation unit comprises a hollow housing supporting a plurality of catalyst coated gas burners of cellular ceramic construction and having a high surface-tovolume ratio. The housing has an intake port and an exhaust port and includes a partition which separates the housing into intake and afterburner compartments; with the gas flow being ...
2Cl-with an E° of +1.36 volts, so chlorine is an oxidizing agent. Redox Process (Oxidation & Reduction Reaction) of Zinc & Copper. Redox events are identified by a change in current at a given potential and the center of that peak is determined as shown in red. In order to evaluate redox titrations, the shape of the corresponding titration curve must be obtained. For example, the redox potential for a lithium ion gaining an electron is shown as the half-reaction: Li + + e--> Li with an E° value of -3.05 volts, indicating that lithium is a strong reducing agent. Typical applications include corrosion monitoring or rusting for example. The C(pH,E)MD method is available since Amber version 18. Or, another example, -0.3 is relatively more positive than -0.9. It also looks at how you go about choosing a suitable oxidising agent or reducing agent for a particular reaction. Oxidation reduction potential (ORP) otherwise known as a REDOX potential measures an aqueous systems capacity to either release ...
TY - JOUR. T1 - Enhanced tissue production through redox control in stem cell-laden hydrogels. AU - Reid, Branden. AU - Afzal, Junaid M.. AU - Mccartney, Annemarie M.. AU - Abraham, M. Roselle. AU - ORourke, Brian. AU - Elisseeff, Jennifer Hartt. PY - 2013/9/1. Y1 - 2013/9/1. N2 - Cellular bioenergetics and redox (reduction-oxidation) play an important role in cell proliferation and differentiation, key aspects of building new tissues. In the present study, we examined the metabolic characteristics of human adipose-derived stem cells (hASCs) during proliferation and differentiation in both monolayer and three-dimensional biomaterial scaffolds. In monolayer, hASCs exhibited higher glycolysis and lower ox-phos as compared to both adipogenic and osteogenic differentiated cells, and hASCs demonstrated the Warburg effect (aerobic glycolysis). However, reactive oxygen species (ROS) levels increased during adipogenic differentiation, but decreased during osteogenic differentiation. Similarly, a ...
It is crucial to develop a catalyst made of earth-abundant elements highly active for a complete oxidation of methane at a relatively low temperature. NiCo2O4 consisting of earth-abundant elements which can completely oxidize methane in the temperature range of 350-550 °C. Being a cost-effective catalyst, NiCo2O4 exhibits activity higher than precious-metal-based catalysts. Here we report that the higher catalytic activity at the relatively low temperature results from the integration of nickel cations, cobalt cations and surface lattice oxygen atoms/oxygen vacancies at the atomic scale. In situ studies of complete oxidation of methane on NiCo2O4 and theoretical simulations show that methane dissociates to methyl on nickel cations and then couple with surface lattice oxygen atoms to form -CH3O with a following dehydrogenation to −CH2O; a following oxidative dehydrogenation forms CHO; CHO is transformed to product molecules through two different sub-pathways including dehydrogenation of OCHO ...
Fingerprint Dive into the research topics of Microfluidic photoinduced chemical oxidation for Ru(bpy),sub,3,/sub, ,sup,3 +,/sup, chemiluminescence - A comprehensive experimental comparison with on-chip direct chemical oxidation. Together they form a unique fingerprint. ...
Free Online Library: Prepartum body condition score affects milk yield, lipid metabolism, and oxidation status of Holstein cows. by Asian - Australasian Journal of Animal Sciences; Agricultural industry Biological sciences College football Analysis Physiological aspects Dairy industry Dairy products industry Enzyme-linked immunosorbent assay Enzymes Fatty acids Football (College) Superoxide Superoxides Vitamin A
Thermal treatments prior or during chemical oxidation of aged polycyclic aromatic hydrocarbon (PAH)-contaminated soils have already shown their ability to
Free practice questions for High School Chemistry - Balancing Oxidation-Reduction Reactions. Includes full solutions and score reporting.
The thermodynamics for the first electron transfer step for sulfide and oxygen indicates that the reaction is unfavorable as unstable superoxide and bisulfide radical ions would need to be produced. However, a two electron transfer is favorable as stable S(0) and peroxide would be formed, but the partially filled orbitals in oxygen that accept electrons prevent rapid kinetics. Abiotic sulfide oxidation kinetics improve when reduced iron and/or manganese are oxidized by oxygen to form oxidized metals which in turn oxidize sulfide. Biological sulfur oxidation relies on enzymes that have evolved to overcome these kinetic constraints to affect rapid sulfide oxidation. Here we review the available thermodynamic and kinetic data for H2S and HS• as well as O2, reactive oxygen species, nitrate, nitrite and NOx species. We also present new kinetic data for abiotic sulfide oxidation with oxygen in trace metal clean solutions that constrain abiotic rates of sulfide oxidation in metal free solution and agree with
MCOs catalyze one-electron oxidation processes, and four molecules of substrate are oxidised in order to reduce a dioxygen molecule to two waters molecules. Substrate oxidation occurs at the mononuclear T1 centre and then the electrons are shuttled, along a T1 coordinating cisteine, to the two histidines that are coordinating the T3 coppers of the trinuclear centre (Figure 1b), where reduction of dioxygen occurs [2, 4, 11]. This constitutes a HCH conserved motif characteristically found in MCOs. Four electrons, as well as four protons, are used to reduce a molecule of dioxygen with the concomitant formation of two water molecules [1, 2, 12]. Electrons needed for this process are obtained through the oxidation of a variety of substrates, but not much is known about the mechanism of proton transfer during this process. Recently, site directed mutagenesis studies suggest that Asp112 of CueO (Asp 116 in CotA; Figure 1c) [13, 14], a conserved residue that is located in the exit channel in close ...
Recall that chemical reactions are all about electrons. In redox (an often used shorthand term for oxidation-reduction) reactions, one is concerned with how electrons are transferred from one species (element, ion, compound) to another. The law of conservation of charge stipulates that if one species loses electrons, there must be another species that gains the electrons. The term oxidation refers to any process that loses electrons. This is a tricky word for some because oxidation sounds like it might only involve oxygen. In truth, oxygen is an important element in redox reactions, and because of its large electronegativity, causes many other elements to give it electrons. Since oxygen often forces other elements to lose electrons, the process of losing electrons became known as oxidation. Reduction is a similarly troubling word, since it refers to a process that gains electrons. In this case, the word reduce has nothing to do with the quantity of electrons, but rather the change in charge. ...
Recall that chemical reactions are all about electrons. In redox (an often used shorthand term for oxidation-reduction) reactions, one is concerned with how electrons are transferred from one species (element, ion, compound) to another. The law of conservation of charge stipulates that if one species loses electrons, there must be another species that gains the electrons. The term oxidation refers to any process that loses electrons. This is a tricky word for some because oxidation sounds like it might only involve oxygen. In truth, oxygen is an important element in redox reactions, and because of its large electronegativity, causes many other elements to give it electrons. Since oxygen often forces other elements to lose electrons, the process of losing electrons became known as oxidation. Reduction is a similarly troubling word, since it refers to a process that gains electrons. In this case, the word reduce has nothing to do with the quantity of electrons, but rather the change in charge. ...
Reactive oxygen species (ROS) are generated in all aerobic organisms. Free radicals are highly reactive ROS that cause damage to biological materials. Fish is rich in polyunsaturated fatty acids, and hence, very prone to lipid peroxidation. Both lipid and protein oxidations are important for quality loss during storage of fish, with high impact on taste and texture. Also, there are interactions between protein and secondary lipid oxidation products (aldehydes) that occur in foods because the oxidation products from one reaction can further react with both lipids and proteins respectively. This review focuses on the mechanisms and pathways of the lipid and protein oxidation and their possible relationship. Additionally, the target amino acids and final impacts of this relationship were considered. We propose that the products of lipid oxidation promote protein oxidation in fish rather than the other way around specially, during frozen storage, while during postmortem changes protein oxidation ...
Cysteine Oxidation Prediction Program Goal: Create a program that will use physicochemical parameters to predict reactive surface cysteine thiols Methods: -Gather examples of proteins susceptible to cysteine oxidation -Extract parameters from Protein Data Bank -Use computer classifier C4.5 to determine rules that will predict if cysteine can become oxidized
A 0.4 wt%Pt/Ce0.76Zr0.19Zn0.05O1.95 catalyst was prepared by the evaporative drying method. The catalytic toluene oxidation activity of the catalyst was investigated and the calcination temperature dependence on the toluene oxidation activity was characterized. It was confirmed that only CO2 and steam were produced by the complete oxidation of toluene, and no toluene-derived compounds were detected as by-products with a gas chromatography-mass spectrometer. Toluene was completely oxidized at 320 °C on the 0.4 wt%Pt/Ce0.76Zr0.19Zn0.05O1.95 catalyst calcined at 500 °C. The toluene oxidation activity slightly decreased with increasing the calcination temperature of the catalyst. However, significant deactivation was not recognized in the present 0.4 wt%Pt/Ce0.76Zr0.19Zn0.05O1.95 catalyst, and toluene was completely oxidized at 360 °C even after calcination at 1000 °C. From these results, it became obvious that the 0.4 wt%Pt/Ce0.76Zr0.19Zn0.05O1.95 catalyst has high thermal stability for toluene
Felter, T. E. and Weinberg, W. H. and Lastushkina, G. Ya. and Zhdan, P. A. and Boreskov, G. K. and Hrbek, J. (1982) A photoelectron spectroscopy study of methanol adsorption and oxidation on Ag(111). Journal of Vacuum Science and Technology, 20 (3). pp. 887-888. ISSN 0022-5355. https://resolver.caltech.edu/CaltechAUTHORS:20120716-110746998 ...
Abstract: Density functional theory (DFT) calculations were used to investigate the structural and electronic properties of V-, Cr-, Pd-, Pt-, and Au-doped titania nanotube arrays (TNTAs) where Ti was replaced by dopants. The adsorption of CO and the formation of CO2 on these various nanotube arrays were also studied in detail. We found that CO physisorbed weakly inside the TNTAs and CO was oxidized by lattice oxygen to form CO2 by the redox mechanism. This may thus be attributed to the unique confinement effect and to different metal doping. All the metal doped systems except the Cr-TNTAs showed a lower activation energy barrier than the undoped TNTAs, indicating that proper metal dopants can promote CO oxidation. The reaction on the Pd- or Au-doped TNTAs had the lowest barrier. Therefore, we found that Pd- or Au-doped TNTAs led to enhanced catalytic activity for CO oxidation at low temperatures. Key words: Density functional theory, TiO2 nanotube arrays, CO oxidation ...
Aerobic life, from simple single-celled bacterial species to complex eukaryotic organisms, has evolved to depend on the oxidising power of O2 in various metabolic pathways. From energetic adenosine triphosphate (ATP) generation to xenobiotic degradation, the use of O2 as a biological oxidant is widespread and varied in the mechanism of action. Enzymes, such as non-heme iron-dependent oxygenases, catalyse the incorporation of O2 into a wide range of biological molecules and use diverse strategies to activate their substrates.. C-H activation is currently one of the hottest topics in organic chemistry. One way for this activation to occur is the hydroxylation of the C-H bond. In this area, great advances have been made in recent years by the development of bioinspired non-heme aminopyridine iron complexes/H2O2 catalytic systems. Such systems replicate the oxidation mechanism of the elaborate non-heme iron oxygenases with simple iron coordination complexes.. Notwithstanding the biological ...
2017-09-08 - Government implementation of free Senior High School policy is a major poverty reduction mechanism in the country, according to the suspended General Secretary of the Peoples National Convention (PNC), Mr. Atik Mohammed.
Ab initio Molecular Dynamics simulations and static Density Functional Theory calculations have been performed to investigate the reaction mechanism of CO oxidation on Au/CeO 2 catalyst. It is found that under reaction condition CO adsorption significantly labializes the surface atoms of the Au cluster and leads to the formation of isolated Au+-CO species that resides on the support in the vicinity of the Au particle. In this context, we identified a dynamic single-atom catalytic mechanism at the interfacial area for CO oxidation on Au/CeO 2 catalyst, which is a lower energy pathway than that of CO oxidation at the interface with the metal particle. This results from the ability of the single atom site to strongly couple with the redox properties of the support in a synergistic manner thereby lowering the barrier for redox reactions. We find that the single Au+ ion, which only exists under reaction conditions, breaks away from the Au cluster to catalyze CO oxidation and returns to the Au cluster ...
There is a growing concern about pharmaceuticals entering the aquatic environment. Many of these compounds cannot be removed completely in sewage treatment plants. To remove these unwanted medicines from water, oxidative degradation techniques may complement the current purification steps. In this paper we studied the effect of advanced oxidation on the cytostatic drug cyclophosphamide (CP) by comparing thermal plasma activation with UV/H2O2 treatment. Plasma activated water (PAW) contains highly reactive oxygen and nitrogen species (RONS) as a result of electric gas discharges in air over water. CP solutions in tap water were oxidized over a period of 120 min and subsequently analyzed by LC-MS/MS to measure the compound degradation. Plasma activation was applied at 50, 100, or 150 W electric power input and UV/H2O2 treatment was carried out by the addition of H2O2 and placing an UV-C source above the test solution for immediate irradiation. The oxidative degradation of CP in PAW resulted in a ...
Adsorption and catalytic oxidation are two promising technologies for indoor volatile organic compounds (VOCs) removal. Combining experimental and modeling approach, the present study aimed at improving the understanding and modeling of adsorption of water-insoluble VOCs (e.g. toluene), and chemisorption and catalytic oxidization of water soluble VOCs (e.g. formaldehyde). For water-insoluble compounds, a dynamic volumetric method was developed for determination of VOC adsorption isotherm of active carbon at low concentration levels. Diffusion coefficient, partition coefficient and mass transfer coefficient of toluene in activated carbon were obtained by comparing numerical modeling results with the adsorption test data. Two mechanistic models were developed for VOCs removal by activated carbon filter bed. Both models fitted well with experimental data. Based on the combined analysis of the experimental and numerical results, external mass transfer and surface diffusion were found to be
Angewandte Books Chemie Mechanisms of Atmospheric Oxidation of the Alkanes The research area covered by this book is the atmospheric chemistry, atmospheric pollution, and photochemical formation of ozone and photooxidants. It essentially focuses on the oxidation of alkanes and haloalkanes, but it also includes the subsequent oxidation processes of primary oxidation products such as aldehydes, ketones, alcohols, nitrates, hydroperoxides, and multifunctional products. It essentially deals with gas-phase chemistry and photochemistry, and thus it includes neither chemistry in the liquid phase nor heterogeneous chemistry on atmospheric particles. The book provides a fairly large number of data on reaction mechanisms, reaction kinetics, product formation, UV absorption spectra, and photochemical reactions, arranged on nearly 1000 pages, with numerous tables and figures and an exhaustive list of references. This volume is a follow-up of two previous books by Calvert et al. on the atmospheric oxidation ...
Modelled energy availability from 10 redox processes (see Table 3) as a function of temperature and SW:HF mixing ratios at the SMVF and the LCVF. Second axis in
Methods of forming metal compounds such as metal oxides or metal nitrides by sequentially introducing and then reacting metal organic compounds with ozone or with oxygen radicals or nitrogen radicals formed in a remote plasma chamber. The metal compounds have surprisingly and significantly improved uniformity when deposited by atomic layer deposition with cycle times of at least 10 seconds. The metal compounds also do not contain detectable carbon when the metal organic compound is vaporized at process conditions in the absence of solvents or excess ligands.
Reduction and oxidation processes are at the heart of almost all synthetic procedures and organic chemists are keen to have a huge portfolio of slick and modern catalytic reagents performing oxidations or reductions. This new volume is part of the Handbook for Reagents for Organic Synthesis series, making use of the leading reagent database e-EROS. It compiles essential reagents in this area, starting with an introductory section discussing the main classes of oxidation catalysts, followed by an alphabetical list of reagents, with an attempt to keep families of catalysts organized by related chemistry for ease of use ...
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The role of the first excited state of oxygen (1D) is proven essential for the description of terminal iodine-oxygen chemical bonds. The description of the I-O bond as a dative one from iodine to O(1D) provides a simple and accurate picture which explains the oxidation properties of iodosobenzene and similar
Emerging data strongly suggest that the oxidation of DNA bases can contribute to genomic instability. Structural changes to DNA, induced by base oxidation, may reduce the fidelity of DNA replication and interfere with sequence-specific DNA−protein interactions. We have examined the structures of a series of pyrimidine deoxynucleoside oxidation damage products in aqueous solution. The modified nucleosides studied include the deoxynucleoside derivatives of 5-hydroxyuracil, 5-hydroxycytosine, 5-(hydroxymethyl)uracil, 5-(hydroxymethyl)cytosine, 5-formyluracil, and 5-formylcytosine. The influence of base oxidation on ionization constants, sugar conformation, and tautomeric configuration has been determined on the basis of UV, proton, and nitrogen NMR spectra of the ^(15)N-enriched derivatives. The potential biological consequences of the structural perturbations resulting from base oxidation are discussed. ...
Superoxide, produced photochemically as well as microbially, is an important reactant present in seawater and a major source of hydrogen peroxide. Superoxide decay may occur through catalyzed or uncatalyzed dismutation forming H2O2 and O2, through oxidation to O2, or through reduction into H2O2. Under definite circumstances, the redox processes that are different from dismutation could produce or consume H+, thereby altering the pH of seawater. In order to alter the pH, these processes have to involve, together with O2•, redox couples that exchange e and H+ in a ratio other than 1:1. This potential pH modification is dependent on several factors, including the extent of H+ imbalance, the rate of formation/transformation of superoxide (which reaches a steady-state concentration in seawater), and the alkalinity of seawater (which varies globally from 2.10 to 2.45 mmol L1 and buffers the pH variations). In the present study, an estimate of the possible pH changes associated with photochemically
Induced degradation of Malathion in aqueous solutions with advanced oxidation processes (AOPs), using ultraviolet irradiation (UV), ozonation and chemical oxidation using (sodium hypochlorite, calcium hypochlorite, monochloride-isocyanuric acid (MCICA), dichloroiso-cyanuric acid (DCICA), trichloroisocyanuric acid (TCICA) was studied. Malathion and its degradation products were extracted using solid phase extraction (SPE) method, identified using GC-MS. Results showed that the degradation of malathion in aqueous solutions followed the first order reaction, and its half life was 2.37, 4.53, 6.64 and 8.84 h under ozonation, UV, 1.5% TCICA and 1.5% DCICA, respectively when malathion solutions treated for 12 h. The concentrations of chemical oxidative substances, active chlorine content and time of treatments had a significant effect on degradation rate of Malathion, which increased with increasing of each. The most enhancement of Malathion degradation was observed in treatment with ozonation, UV, ...
We herein report that a copper-ion-exchanged erionite zeolite (Cu-ERI) exhibited a methanol yield as high as 147 μmol/g-zeolite, equaling 0.224 μmol/μmol-Cu, in the direct oxidation of methane to methanol. Moreover, this high methanol yield was achieved using an isothermal chemical looping with both oxygen activation and reaction with methane carried out at 300 °C, in contrast to the conventional stepwise protocol where activation is performed at high temperature (450 °C and above) and the methane reaction at lower temperature (typically 200 °C). Under isobaric condition (1 bar), the Cu-ERI still gave a high yield of 80 μmol/g-zeolite after a single aqueous extraction of the methanol. Such improvements indicate that high yields can be obtained over Cu-ERI in the direct conversion of methane to methanol by a chemical looping without any temperature or pressure swing.. ...
In the present study, a comparative assessment of 2,4,6-T (2,4,6-Trichlorophenol) degradation by different AOPs (Advanced Oxidation Processes - UV, U
Read Comparison on mineralization of 2,4,6-tribromophenol by UV-based advanced oxidation processes: UV/Na2S2O8 and UV/H2O2, Research on Chemical Intermediates on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.
Macrophage activation is characterized by pronounced metabolic adaptation. Classically activated macrophages show decreased rates of mitochondrial fatty acid oxidation and oxidative phosphorylation and acquire a glycolytic state together with their pro-inflammatory phenotype. In contrast, alternatively activated macrophages require oxidative phosphorylation and mitochondrial fatty acid oxidation for their anti-inflammatory function. Although it is evident that mitochondrial metabolism is regulated during macrophage polarization and essential for macrophage function, little is known on the regulation and role of peroxisomal β-oxidation during macrophage activation. In this study, we show that peroxisomal β-oxidation is strongly decreased in classically activated bone-marrow-derived macrophages (BMDM) and mildly induced in alternatively activated BMDM. To examine the role of peroxisomal β-oxidation in macrophages, we used Mfp2-/- BMDM lacking the key enzyme of this pathway. Impairment of peroxisomal β
TY - JOUR. T1 - Onset of the aerobic nitrogen cycle during the Great Oxidation Event. AU - Zerkle,Aubrey L.. AU - Poulton,Simon W.. AU - Newton,Robert J.. AU - Mettam,Colin. AU - Claire,Mark W.. AU - Bekker,Andrey. AU - Junium,Christopher K.. PY - 2017/2/23. Y1 - 2017/2/23. N2 - The rise of oxygen on the early Earth (about 2.4 billion years ago) caused a reorganization of marine nutrient cycles, including that of nitrogen, which is important for controlling global primary productivity. However, current geochemical records lack the temporal resolution to address the nature and timing of the biogeochemical response to oxygenation directly. Here we couple records of ocean redox chemistry with nitrogen isotope (15N/14N) values from approximately 2.31-billion-year-old shales of the Rooihoogte and Timeball Hill formations in South Africa, deposited during the early stages of the first rise in atmospheric oxygen on the Earth (the Great Oxidation Event). Our data fill a gap of about 400 million years in ...
Highly reactive transition metal-oxo intermediates are important active oxidant involved in numerous enzymes such as cytochrome P450 monooxygenases as well as in many useful metal-catalyzed oxidations. Many transition metal catalysts are designed for biomimetic studies of the predominant oxidation catalysts in Nature, the cytochrome P450 enzymes. In this work, a series of metalloporphyrin and metallocorrole complexes have been successfully synthesized and spectroscopically characterized by UV-vis, GCMS and 1H-NMR. The utilization of these complexes as catalysts for selective oxidation of sulfides and photocatalytic aerobic oxidations of activated hydrocarbons were investigated. Ruthenium(II) porphyrin complexes (2) and iron(III) corrole complexes (4) with iodobenzene diacetate [PhI(OAc)2] as a mild and excellent oxygen source efficiently catalyzed sulfides to sulfoxides under mild conditions. Ruthenium porphyrins (2) catalyzed the highly selective oxidation of para-substituted thioanisoles and allylic
The annual meeting of the Israel Society for Oxygen and Free Radical Research (ISOFRR) will take place at. Tel Aviv University on Monday, February 26, 2018. The meeting will be dedicated to recent advances in redox biology, chemistry and medicine (see also attached program):. Oxidative stress and neurodegeneration:. Prof. Ruth Gabizon (Hebrew University). Prof. Daniel Offen (Tel Aviv University). Prof. Daphne Atlas (Hebrew University). Prof. Dan Frenkel (Tel Aviv University). Applications of redox chemistry:. Prof. Ehud Gazit (Tel Aviv University). Prof. Aharon Gedanken (Bar-Ilan University ...
The high cost, scarcity, and poor stability of metallic platinum (Pt) as an oxygen reduction reaction (ORR) catalyst in fuel cells and metal-air batteries have limited the commercialization of these attractive clean-energy technologies. Thus, developing alternative electrocatalysts that are economical and achieve maximized efficiency of stably catalyzing ORR is of prime importance in the societal pursuit of sustainable energy. Metallic palladium (Pd) is an alternative electrocatalyst that is less expensive than Pt; however, its current performance remains insufficient. Here we report for the first time that the ORR activity of the different oxidation states of Pd increased in the following order: Pd0 , Pd2+ , perovskite-type ionic (Pi) Pd3/4+. Especially, the intrinsic activity on Pd active site of (Pi) Pd3/4+ is ~84-fold higher than that of Pd0. By doping the Pd element as a cation into the perovskite oxide lattice to form LaFe0.95Pd0.05O3-δ and LaFe0.9Pd0.1O3-δ, unusual oxidation states of ...
By inducing distortion in transmembrane alpha-helices, proline residues can act as molecular hinges (4). We hypothesized that DsbDβs conserved prolines could be important for the correct positioning of Cys163 and Cys285, allowing oxidation/reduction cycles to occur. We therefore postulated that replacement of these proline residues might alter the oxidation/reduction cycle of Cys163 and Cys285, possibly by inducing some rigidity in the transmembrane domain. Katzen and Beckwith have shown that Cys163 and Cys285 are found reduced in vivo (10). However, we have observed that they are susceptible to air oxidation, as they are found in the oxidized form after extraction and solubilization procedures. To determine whether the proline-to-alanine mutations may alter the susceptibility to air oxidation and thus possibly the oxidation/reduction cycle of Cys163 and Cys285, the individual proline mutants were overexpressed, extracted, and solubilized in 1% Triton. The free cysteine residues were modified ...
The patented Cool-Ox process uses chemical oxidation (ISCO) and reduction (ISCR) to treat a variety of hydrocarbons, halogenated compounds, brine and coal tar/MGP sites. It is non-corrosive and does not generate heat, so it is gentle on vegetation and will not harm utilities in the treatment area.
Oxidative stress and the formation of amyloid plaques containing amyloid-β (Aβ) peptides are two key hallmarks of Alzheimers disease. A proportion of methionine (Met) at position 35 within Aβ is oxidized to methionine sulphoxide (Met(OX)) within the Alzheimers plaques. These oxidative processes may be the key to understanding the early stages of Alzheimers disease. In vitro oxidation of Aβ, by the physiological oxidant H2O2, was monitored using (1)H NMR and mass spectrometry. Here we investigate the effect of Aβ methionine oxidation on fiber formation kinetics and morphology using the amyloid specific fluorescence dye Thioflavin T (ThT) and Transmission Electron Microscopy (TEM). Methionine oxidation reduces the total amount of fibers generated for both dominant forms of Aβ, however there are marked differences in the effect of Met(OX) between Aβ(1-40) and Aβ(1-42). Surprisingly the presence of Met(OX) reduces lag-times for Aβ(1-40) fiber formation but extends lag-times for ...
PLATINUM BASED CATALYST FOR OXIDATION/REDUCTION REACTION AND ITS USE - Disclosed herein are a platinum-based catalyst for oxidation/reduction reactions and the use thereof. The platinum-based catalyst is prepared by loading a catalyst composition comprising a water soluble salt of at least one metal selected from among cerium (Ce), zirconium (Zr) and rhenium (Re), on a support comprising at least one selected from among alumina, silica and titania. The disclosed catalyst can be prepared in a simple manner without any particular limitation as to the kind of usable water soluble platinum salt, and when it is applied to various oxidation reactions, including water gas shift reactions of carbon monoxide, three-way catalytic reactions, and selective oxidation reactions of carbon monoxide, and to reduction reactions, such as reactions of removing nitrogen oxide (NOx), it will show excellent catalytic activity. In particular, the disclosed catalyst shows excellent performance even in a specific ...
TY - JOUR. T1 - Chiral Co(II) metal-organic framework in the heterogeneous catalytic oxidation of alkenes under aerobic and anaerobic conditions. AU - Tuci, Giulia. AU - Giambastiani, Giuliano. AU - Kwon, Stephanie. AU - Stair, Peter C.. AU - Snurr, Randall Q.. AU - Rossin, Andrea. PY - 2014/3/7. Y1 - 2014/3/7. N2 - The chiral Co(II) MOF [Co(l-RR)(H2O)·H2O] ∞ [1; l-RR = (R,R)-thiazolidine-2,4-dicarboxylate] has been exploited in the catalytic oxidation of different alkenes (cyclohexene, (Z)-cyclooctene, 1-octene) using either tert-butyl hydroperoxide ( tBuOOH) or molecular oxygen (O2) as oxidants. Different chemoselectivities are observed, both substrate- and oxidant-dependent. A moderate enantioselectivity is also obtained in the case of prochiral precursors, revealing the chiral induction ability of the optically pure metal environment. The interaction of O2 with the exposed metal sites in 1 (after material preactivation and consequent removal of the coordinated aquo ligand) has been ...
The mechanisms underlying neuron death in Parkinsons disease are unknown, but both genetic defects and environmental factors are implicated in its pathogenesis. Mutations in the parkin gene lead to autosomal recessive juvenile Parkinsonism (AR-JP). Here we report that compared to control flies, Drosophila lacking parkin show significantly reduced lifespan but no difference in dopamine neuron numbers when raised on food supplemented with environmental pesticides or mitochondrial toxins. Moreover, chelation of redox-active metals, anti-oxidants and overexpression of superoxide dismutase 1 all significantly reversed the reduced longevity of parkin-deficient flies. Finally, parkin deficiency exacerbated the rough eye phenotype of Drosophila caused by overexpression of the copper importer B (Ctr1B). Taken together, our results demonstrate an important function of parkin in the protection against redox-active metals and pesticides implicated in the etiology of Parkinsons disease. They also ...
starvation synthase AT1G05010 0.19 0.28 0.28 0.30 0.55 defense response ACC oxidase AT1G70850 8.85 7.24 9.49 22.18 24.40 defense response Bet v I allergen protein AT1G70890 5.34 5.37 5.19 5.05 5.82 defense response major latex protein AT2G43535 4.12 4.42 6.13 6.32 5.08 defense response trypsin inhibitor AT2G44110 0.40 0.45 0.39 0.43 0.36 defense response seven transmembrane MLO protein AT4G11280 2.25 1.87 2.29 2.00 2.34 defense response ACC synthase 6 AT3G52920 2.00 3.09 2.82 3.88 4.19 defense response expressed protein AT5G65970 2.91 2.60 2.88 2.84 3.05 defense response seven transmembrane MLO protein AT5G09980 0.51 0.35 0.38 0.28 0.38 defense response expressed protein AT4G11190 17.22 5.56 9.98 9.71 8.84 defense response disease resistance-responsive protein AT1G50560 2.67 1.77 2.32 2.50 2.52 oxidation reduction cytochrome P450 AT1G72230 3.18 2.45 3.09 2.98 2.66 oxidation reduction plastocyanin like protein AT3G20130 1.85 1.72 1.73 1.89 1.65 oxidation reduction cytochrome P450 AT2G34500 3.53 ...
An electrode for detecting interactions between members of a binding pair, which electrode has been modified by formation of a non-conductive self-assembled monolayer, and a method of detecting biomolecules, such as nucleic acids or other targets, including receptors, ligands, antigens or antibodies, utilizing such an electrode. When contacted with a target nucleic acid, an oligonucleotide probe coupled to the self-assembled monolayer reacts with the target nucleic acid form a hybridized nucleic acid on the modified electrode surface. The hybridized nucleic acid is reacted with a transition metal complex capable of oxidizing a preselected base in the hybridized nucleic acid in an oxidation-reduction reaction, the oxidation-reduction reaction is detected, and the presence or absence of the nucleic acid is determined from the detected oxidation-reduction reaction.
An electrode for detecting interactions between members of a binding pair, which electrode has been modified by formation of a non-conductive self-assembled monolayer, and a method of detecting biomolecules, such as nucleic acids or other targets, including receptors, ligands, antigens or antibodies, utilizing such an electrode. When contacted with a target nucleic acid, an oligonucleotide probe coupled to the self-assembled monolayer reacts with the target nucleic acid form a hybridized nucleic acid on the modified electrode surface. The hybridized nucleic acid is reacted with a transition metal complex capable of oxidizing a preselected base in the hybridized nucleic acid in an oxidation-reduction reaction, the oxidation-reduction reaction is detected, and the presence or absence of the nucleic acid is determined from the detected oxidation-reduction reaction.
Irrigation of the municipal cemetery in Brigham City, Utah resulted in stained headstones in 2001 and 2002. The water used in the irrigation came from Mantua reservoir, a medium sized impoundment situated near the mouth of Box Elder Canyon. In order for Brigham City to establish a city wide secondary pressurized irrigation system using water from Mantua reservoir, the cause and the source of staining problem must be determined. Previous research (Wallace 2006) determined that the source of the staining was the reduction of iron found in Mantua Reservoir sediments that occurred when seasonal variations in the reservoir caused anaerobic conditions. The reduced iron then dissolved in the water and was used in the irrigation system, causing re-oxidation of the iron. The oxidized iron then precipitated out on the headstones causing the staining. The purpose of this investigation is to determine the iron oxidation kinetics after the re-aeration of the water which will help determine appropriate ...
TY - JOUR. T1 - Influence of diesel post injection timing on HC emissions and catalytic oxidation performance. AU - Yamamoto, Kanta. AU - Takada, Keishi. AU - Kusaka, Jin. AU - Kanno, Yasuharu. AU - Nagata, Makoto. PY - 2006/1/1. Y1 - 2006/1/1. N2 - For diesel emission control systems containing a Diesel Oxidation Catalyst (DOC) and a Catalyzed Soot Filter (CSF) the DOC is used to oxidize the additional fuel injected into the cylinder and/or the exhaust pipe for the purpose of increasing the CSF inlet temperature during the soot regeneration. Hydrocarbon (HC) oxidation performance of the DOC is affected by HC species as well as a catalyst design, i.e., precious metal species, support materials and additives. How engine-out HC species vary as a function of fuel supply conditions is not well understood. In addition, the relationship between catalyst design and oxidation activity of different hydrocarbon species requires further study. In this study, diesel fuel was supplied by in-cylinder, post ...
Advanced Level Theoretical Organic Chemistry Revision Notes on REDOX reactions involving organic oxidation and reduction synthesis-preparations. Reactions involving the oxidation or reduction of the starting reactant molecules and the chemistry of the appropriate oxidising agents and reducing reagents is described and discussed.
Geobacillus thermoglucosidasius is a Gram-positive, thermophilic bacterium capable of ethanologenic fermentation of both C5 and C6 sugars and may have possible use for commercial bioethanol production [Tang et al., 2009; Taylor et al. (2009) Trends Biotechnol 27(7): 398-405]. Little is known about the physiological changes that accompany a switch from aerobic (high redox) to microaerobic/fermentative (low redox) conditions in thermophilic organisms. The changes in the central metabolic pathways in response to a switch in redox potential were analyzed using quantitative real-time PCR and proteomics. During low redox (fermentative) states, results indicated that glycolysis was uniformly up-regulated, the Krebs (tricarboxylic acid or TCA) cycle non-uniformly down-regulated and that there was little to no change in the pentose phosphate pathway. Acetate accumulation was accounted for by strong down-regulation of the acetate CoA ligase gene (acs) in addition to up-regulation of the pta and ackA genes ...
The electron transfer properties of proteins are normally measured as molecularly averaged ensembles. Through these and related measurements, proteins are widely regarded as macroscopically insulating materials. Using scanning tunnelling microscopy (STM), we present new measurements of the conductance through single-molecules of the electron transfer protein cytochrome b562 in its native conformation, under pseudo-physiological conditions. This is achieved by thiol (SH) linker pairs at opposite ends of the molecule through protein engineering, resulting in defined covalent contact between a gold surface and a platinum-iridium STM tip. Two different orientations of the linkers were examined: a long-axis configuration (SH-LA) and a short-axis configuration (SH-SA). In each case, the molecular conductance could be gated through electrochemical control of the heme redox state. Reproducible and remarkably high conductance was observed in this relatively complex electron transfer system, with ...
TY - JOUR. T1 - Hydrogen sulfide is a partially redox-independent activator of the human jejunum Na+ channel, NAv1.5. AU - Strege, Peter R.. AU - Bernard, Cheryl E.. AU - Kraichely, Robert E.. AU - Mazzone, Amelia. AU - Sha, Lei. AU - Beyder, Arthur. AU - Gibbons, Simon J.. AU - Linden, David R.. AU - Kendrick, Michael L.. AU - Sarr, Michael G.. AU - Szurszewski, Joseph H.. AU - Farrugia, Gianrico. PY - 2011/6/1. Y1 - 2011/6/1. N2 - Hydrogen sulfide (H2S) is produced endogenously by L-cysteine metabolism. H2S modulates several ion channels with an unclear mechanism of action. A possible mechanism is through reduction-oxidation reactions attributable to the redox potential of the sulfur moiety. The aims of this study were to determine the effects of the H2S donor NaHS on Nav1.5, a voltage-dependent sodium channel expressed in the gastrointestinal tract in human jejunum smooth muscle cells and interstitial cells of Cajal, and to elucidate whether H2S acts on Nav1.5 by redox reactions. Whole cell ...
Oxidation-reduction (redox) reactions are important in drinking water treatment and distribution. Oxidation-reduction potential (ORP) measurements of water reflect the tendency of major constituents in the water to accept or lose electrons. Although ORP measurements are valuable and can provide useful information toward protecting public health, they are not widely performed by the drinking water community for a variety of reasons. The objective of this research is to report the impact of five oxidants commonly used in drinking water as well as the pH on the measured ORP of water. Results show that the ORP of each oxidant system increased with increasing oxidant concentration to a maximum and decreased with increasing pH. Chlorine and chlorine dioxide waters had the greatest ORP followed by water containing monochloramine and permanganate, and water containing only oxygen. Duplicate ORP measurements revealed some inconsistencies with redox electrode measurements.. ...
The redox interactions between HAuCl4 and a series of π-conjugated organic donors, namely carboxylated dithiafulvenes and tetrathiafulvalene vinylogues, were investigated. Interestingly, the dithiafulvene derivative with two carboxylic groups showed the ability to directly induce the formation of Au(0) nanop
Our results demonstrate that maxi-K channels in smooth muscle cells are regulated by agents that alter the redox state of sulfhydryl groups. We have shown that sulfhydryl reduction increases nPo of the channel whereas oxidation has the opposite effect. Maxi-K channels in patches pulled from smooth muscle cells appear to exist in a mixed redox state, since either reduction or oxidation markedly affected channel activity. This mixed redox state could occur either because some channels in the patch exist in the reduced state whereas others are in the oxidized state, or because each channel has more than one redox modulatory site existing in different redox states. Since membrane patches from airway myocytes always contain multiple channels, we could not differentiate between these two possibilities.. We compared the normalized conductance-voltage curves constructed from macroscopic currents in response to step-depolarization during control and after sulfhydryl reduction to determine whether ...
Guanine is the most readily oxidized of the four DNA bases, and guanine oxidation products cause G:C-T:A and G:C-C:G transversions through DNA replication. 8-Oxo-7,8-dihydroguanine (8-oxoG) causes G:C-T:A transversions but not G:C-C:G transversions, and is more readily oxidized than guanine. This review covers four major findings. (i) 2,2,4-Triamino-5(2H)-oxazolone (Oz) is produced from guanine and 8-oxoG under various oxidative conditions. Guanine is incorporated opposite Oz by DNA polymerases, except REV1. (ii) Several enzymes exhibit incision activity towards Oz. (iii) Since the redox potential of GG is lower than that of G, contiguous GG sequences are more readily oxidized by a one-electron oxidant than a single guanine, and OzOz is produced from GG in double-stranded DNA. Unlike most DNA polymerases, DNA polymerase ζ efficiently extends the primer up to full-length across OzOz. (iv) In quadruplex DNA, 3′-guanine is mainly damaged by one-electron oxidation in quadruplex DNA, and this damage
Fe-implanted Si-wafers have been oxidized at 900 °C and 1100 °C in order to investigate the behaviour of Fe atoms at the growing SiO{sub 2}/Si interface and the impact on the integrity of microelectronic devices of an involuntary Fe contamination before or during the oxidation process. As-implanted and oxidized wafers have been characterized using secondary ion mass spectroscopy, atom probe tomography, and high-resolution transmission electron microscopy. Experimental results were compared to calculated implantation profiles and simulated images. Successive steps of iron disilicide precipitation and oxidation were evidenced during the silicon oxidation process. The formation of characteristic pyramidal-shaped defects, at the SiO{sub 2}/Si interface, was notably found to correlate with the presence of β-FeSi{sub 2} precipitates. Taking into account the competitive oxidation of these precipitates and of the surrounding silicon matrix, dynamic mechanisms are proposed to model the observed ...
Acid-Treated Nickel-Rich Platinum-Nickel Alloys for Oxygen Reduction and Methanol Oxidation Reactions in Alkaline MediaAcid-Treated Nickel-Rich Platinum-Nickel Alloys for Oxygen Reduction and Methanol Oxidation Reactions in Alkaline Media ...
Background: Oxidative modification of low density lipoproteins (LDL) is recognized as one of the major processes involved in atherogenesis. The in vitro standardized measurement of LDL oxidative susceptibility could thus be of clinical significance. The aim of the present study was to establish a method which would allow the evaluation of oxidative susceptibility of LDL in the general clinical laboratory. Results: LDL was isolated from human plasma by selective precipitation with amphipathic polymers. The ability of LDL to form peroxides was assessed by measuring thiobarbituric acid reactive substances (TBARS) after incubation with Cu2+ and H2O2. Reaction kinetics showed a three-phase pattern (latency, propagation and decomposition phases) which allowed us to select 150 min as the time point to stop the incubation by cooling and EDTA addition. The mixture Cu 2+/H2O2 yielded more lipoperoxides than each one on its own at the same time end-point. Induced peroxidation was measured in normal ...
TY - JOUR. T1 - Plant redox proteomics. AU - Navrot,Nicolas. AU - Finnie,Christine. AU - Svensson,Birte. AU - Hägglund,Per. PY - 2011. Y1 - 2011. N2 - In common with other aerobic organisms, plants are exposed to reactive oxygen species resulting in formation of post-translational modifications related to protein oxidoreduction (redox PTMs) that may inflict oxidative protein damage. Accumulating evidence also underscores the importance of redox PTMs in regulating enzymatic activities and controlling biological processes in plants. Notably, proteins controlling the cellular redox state, e.g. thioredoxin and glutaredoxin, appear to play dual roles to maintain oxidative stress resistance and regulate signal transduction pathways via redox PTMs. To get a comprehensive overview of these types of redox-regulated pathways there is therefore an emerging interest to monitor changes in redox PTMs on a proteome scale. Compared to some other PTMs, e.g. protein phosphorylation, redox PTMs have received less ...
Glucose catabolism via cellular respiration can be grouped into three major metabolic stages, these are (1) glycolysis, (2) the Krebs cycle also known as the citric acid cycle, and the tricarboxylic acid cycle (TCA cycle), and (3) the electron transport chain and oxidative phosphorylation. In eukaryotic cells, glycolysis occurs in the cytoplasm of the cell. The Krebs cycle occurs in the mitochondrial matrix while the reactions of the electron transport chain and oxidative phosphorylation occur on the cristae of the mitochondrion. These pathways rely on oxidation reduction reactions in which electrons are enzymatically removed (oxidation) from glucose and transferred (reduction) to electron acceptor molecules such as nicotinamide adenine dinucleotide (NAD+). Upon receiving electrons, NAD+ is reduced to NADH which functions as an electron carrier that supplies electrons to an electron transport chain in mitochondria that will ultimately power ATP synthesis in the reactions known as oxidative ...
Activation of Ca2+-sensitive, large-conductance potassium (BK) channels in vascular smooth muscle cells (VSMCs) by local, ryanodine receptor-mediated Ca2+ signals (Ca2+ sparks) acts as a brake on pressure-induced (myogenic) vasoconstriction-a fundamental mechanism that regulates blood flow in small resistance arteries. We report that physiological intraluminal pressure within resistance arteries activated cGMP-dependent protein kinase (PKG) in VSMCs through oxidant-induced formation of an intermolecular disulfide bond between cysteine residues. Oxidant-activated PKG was required to trigger Ca2+ sparks, BK channel activity, and vasodilation in response to pressure. VSMCs from arteries from mice expressing a form of PKG that could not be activated by oxidants showed reduced Ca2+ spark frequency, and arterial preparations from these mice had decreased pressure-induced activation of BK channels. Thus, the absence of oxidative activation of PKG disabled the BK channel-mediated negative feedback ...
Efficient RNA delivery to targeted cells requires the use of stable interactive carriers that provide RNA protection during the extracellular transit and trigger release once internalised. One strategy to avoid the premature extracellular RNA drain coupled to sufficient intracellular release is the use of stimuli-responsive delivery materials exploiting as a triggering mechanism the redox gradient between the extra- and intracellular compartments. This work describes a facile route for preparation of redox-active nanocarriers containing disulphides that combine RNA protection and delivery on demand based on intracellular glutathione (GSH) levels. A one-step sonochemical technology was employed to generate thiolated chitosan (TC) nanocapsules with diameter between 250 - 570 nm and simultaneously load them with RNA. Their size and physiological stability were directly proportional to the extent of disulphide cross-linking, which in turn could be ruled by adjusting the processing pH and degree of ...
A system for controlled heat generation in exhaust pipeline is studied, consisting of fuel injector and oxidation catalyst (plus connecting pipes). A 3D-CFD software (StarCD) coupled with a tailored 1D model of catalytic monolith channel (XMR) are employed for simulations of realistic, fully 3D system geometry. Exhaust gas flow, fuel injection, and distribution at the catalyst inlet is solved by 3D-CFD, while the processes inside individual representative channels are simulated by the effective 1D model. The 3D-CFD software calls iteratively the 1D channel model with proper boundary conditions and solves 3D temperature profile over the monolith, utilizing local enthalpy fluxes (including gas-solid heat transfer and reaction enthalpy) calculated by the 1D channel model.Seven representative hydrocarbons are used for characterisation of Diesel fuel composition with respect to catalytic oxidation kinetics. Each representative component possesses its own light-off behaviour (described by a global ...
Conducting polymer membranes consisting of polypyrrole (PPy) doped with either 8-hydroxyquinoline-5-sulfonic acid (HQS) or 2,9-dimethyl-4,7-diphenyl-1,10-phenanthrolinedisulfonic acid (bathocuproinedisulfonic acid, (BCS)) were prepared electrochemically using aqueous solutions of pyrrole and the respective chelating ligands. The ratio of pyrrole to dopant in the resulting PPy/HQS and PPy/BCS free-standing membranes was found to be 9:1 and 6:1, respectively, whilst the conductivities were comparable (1.13 and 3.40Scm-1, respectively). Cyclic voltammetry studies using electrodes coated with thin films indicated that both polymers undergo reversible oxidation/reduction processes in aqueous solution that are influenced by the nature of the supporting electrolyte. Electrochemically controlled transport of metal ions was demonstrated using laminated membranes (either PPy/BCS or PPy/HQS was deposited onto platinum sputter-coated polyvinylidene filters). Transport of Co2+, Ni2+ and Zn2+ was demonstrated for the
TY - JOUR. T1 - High-frequency fluctuations in redox conditions during the latest Permian mass extinction. AU - Mettam,C.. AU - Zerkle,A. L.. AU - Claire,M. W.. AU - Izon,G.. AU - Junium,C. J.. AU - Twitchett,R. J.. PY - 2017. Y1 - 2017. N2 - New high-resolution geochemical and sedimentological data from Fiskegrav, East Greenland, reveal fluctuations in marine redox conditions associated with the final disappearance of bioturbating organisms during the latest Permian mass extinction (LPME). Sedimentological observations imply a transgressive episode, and associated geochemical evidence for decreasing oxygen availability and the establishment of persistently ferruginous (Fe2+-rich) conditions implies the shoreward migration of oxygen deficient waters. The long-term decline in dissolved oxygen (DO) availability could have been exacerbated by increasing water temperatures, reducing the solubility of oxygen and promoting thermal stratification. Mixing of the water column could have been further ...
The gram-negative metal-reducing microorganism, previously known as strain GS-15, was further characterized. This strict anaerobe oxidizes several short-chain fatty acids, alcohols, and monoaromatic compounds with Fe(III) as the sole electron acceptor. Furthermore, acetate is also oxidized with the reduction of Mn(IV), U(VI), and nitrate. In whole cell suspensions, the c-type cytochrome(s) of this organism was oxidized by physiological electron acceptors and also by gold, silver, mercury, and chromate. Menaquinone was recovered in concentrations comparable to those previously found in gram-negative sulfate reducers. Profiles of the phospholipid ester-linked fatty acids indicated that both the anaerobic desaturase and the branched pathways for fatty acid biosynthesis were operative. The organism contained three lipopolysaccharide hydroxy fatty acids which have not been previously reported in microorganisms, but have been observed in anaerobic freshwater sediments. The 16S rRNA sequence indicated ...
Taking their inspiration from Nature, scientists at the University of New South Wales have developed a new method for carrying out chemical reduction - an industrial process used to produce fuels and chemicals that are vital for modern society.. Their catalyst-based approach has the big advantages that it uses cheap, replenishable reagents and it works well at room temperature and in air - so much so, it can even be carried out safely in a teacup.. The research, by a team led by Associate Professor Stephen Colbran, of the UNSW School of Chemistry, has been published as the cover of the prestigious journal, Angewandte Chemie.. The catalyst they designed mimics the activity of naturally occurring enzymes that catalyse reduction, such as alcohol dehydrogenase in yeast, that helps produce alcohol from sugar.. Industrial chemical reduction processes underpin human existence, but are unsustainable because they irreversibly consume reagents that are made at prohibitively high energy cost, Dr Colbran ...
The objective of this research program is to provide fundamental scientific information on the physical and chemical properties of solutes in aqueous solutions at high temperatures needed to assess and enhance the applicability of hydrothermal oxidation (HTO) to the remediation of DOE hazardous and mixed wastes. Focus areas for this project include measurements of the solubility and speciation of actinides in model HTO process streams at high temperatures, and the experimental and theoretical development of equations of state for aqueous mixtures under HTO process conditions ranging above the critical temperature of water. A predictive level of understanding of the chemical and physical properties of HTO process streams is being developed through molecular-level simulations of aqueous solutions at high temperatures.
TY - JOUR. T1 - Computer-generated high-valent iron-oxo and manganese-oxo species with polyoxometalate ligands. T2 - How do they compare with the iron-oxo active species of heme enzymes?. AU - De Visser, Samüel P.. AU - Kumar, Devesh. AU - Neumann, Ronny. AU - Shaik, Sason. PY - 2004/10/25. Y1 - 2004/10/25. N2 - The structure and reactivity of high-valent FeVO and Mn VIO oxidation catalysts containing a polyoxometalate [PW 11O39]7- lacunary ligand (2) have been investigated by a computational study. Calculations have demonstrated there is an intriguing analogy between these species and the active species (1) of the enzyme cytochrome P450 (see scheme).. AB - The structure and reactivity of high-valent FeVO and Mn VIO oxidation catalysts containing a polyoxometalate [PW 11O39]7- lacunary ligand (2) have been investigated by a computational study. Calculations have demonstrated there is an intriguing analogy between these species and the active species (1) of the enzyme cytochrome P450 (see ...