Cordas, Cristina M., Americo G. Duarte, Jose J. G. Moura, and Isabel Moura. Electrochemical behaviour of bacterial nitric oxide reductase-Evidence of low redox potential non-heme Fe-B gives new perspectives on the catalytic mechanism. Biochimica Et Biophysica Acta-Bioenergetics. 1827.3 (2013): 233-238 ...
Natural Electron ACCEPTORS Nicotinamide Adenine Dinucleotide Phosphate (NADP) used in photosynthesis in chloroplasts NADP + + 2H + + 2e - NADPH + H + Ferredoxin the most difficult to reduce (and most easily oxidised) Cytochromes Conjugate proteins which contain a haem group. The iron atom undergoes redox reactions Fe 3+ + e - Fe 2+ NB The iron atom in the haem group of haemoglobin does not go through a redox reaction Haemoglobin is oxygenated or deoxygenated Reduction Oxidation Reduction Oxidation © 2010 Paul Billiet ODWSODWS
Detection of different oxidation states of individual manganese porphyrins during their reaction with oxygen at a solid/liquid ...
for different oxidation states of the same element in X-ray photoelectron spectroscopy measurements, should the full width half maximum (FWHM) value be the same for all? Is this a parameter to fix in this case for the fitting ...
TY - JOUR. T1 - Low temperature direct oxidation of methane to methanol. AU - Fujimoto, Kaoru. AU - Sekine, Yasushi. PY - 1997. Y1 - 1997. N2 - Methane was oxidized by oxygen at temperatures as low as 473K or lower under pressurized conditions. The reaction was initialed by heated wire, which was set in the center of a pressurized reaction chamber. At the initial stage of the reaction, the methanol selectivity was as high as 90%, but its level decreased quickly with proceeding of the reaction time. When the reaction pressure was raised from 5 to 40atm, the methanol selectivity (at high O2 conversion level) was increased from 2% to 30% whereas selectivities of C2 hydrocarbons of CO2 decreased 30% to 10% or less. A new reaction model was claimed for the present reaction system.. AB - Methane was oxidized by oxygen at temperatures as low as 473K or lower under pressurized conditions. The reaction was initialed by heated wire, which was set in the center of a pressurized reaction chamber. At the ...
N,N-Dialkylhydroxylamines where the alkyl groups are of 10 to 30 carbon atoms are prepared by an improved process involving the direct oxidation of the corresponding N,N-dialkylamines with aqueous hydrogen peroxide in a lower alkanol solvent in the absence of a catalyst or a sequestering agent. The improved process prevents the problem of over-oxidation and gives the desired N,N-dialkylhydroxylamine in high yield and purity. The N,N-dialkylhydroxylamines are effective stabilizers for polymer compositions particularly as process stabilizers for polyolefins.
From the stock market to politics, keeping gains and losses straight these days can be confusing. Scientific gains and losses can be equally overwhelming. Thankfully, in Mondays Scientific Spotlight Session on Redox Biology in Thrombosis, the pathways involved in electron losses and gains and their effect on platelet biology were highlighted by two thought leaders.. Reactive oxygen species (ROS), a type of unstable molecule, are a natural byproduct of aerobic metabolism involved in endogenous signaling. A buildup of ROS is associated with oxidative stress and is implicated in disease states, including atherosclerosis, diabetes, neurodegeneration, and aging. ROS and redox biology have received significant attention in vascular biology; however, there has previously been little focus on ROS production by, and influences on, platelet function. Co-Chair Craig Morrell, DVM, PhD, explored the intersection of platelets and thrombosis through investigating the role of ROS in platelet function. Dr. ...
Oxidation Processes in Water and Wastewater Treatment Conference scheduled on October 01-02, 2020 in October 2020 in Dubrovnik is for the researchers, scientists, scholars, engineers, academic, scientific and university practitioners to present research activities that might want to attend events, meetings, seminars, congresses, workshops, summit, and symposiums.
Redox Biology is a forum for novel research, methods and review articles in redox biology in the areas of both health and disease. Acceptable paper...
Tasks:. Scientific tasks are primarily placed within the oxidation area where model studies are used to describe the mechanisms behind oxidation processes in proteins as well as in protein-/lipid models. The models are particularly used to study how oxidation affects the protein structure and how the protein structure influences different oxidation processes (e.g. light, enzymes and transition metal ions). Accessibility of proteases is also used as a measurement of changes of the protein structure (at primary and higher protein structure levels) after oxidation. Knowledge from model studies is carried on to dairy products such as milk, powder and cheese where the oxidation processes are described as direct measurement of primary oxidation products (e.g. free radicals and protein and lipid peroxides) and also secondary oxidation products (e.g. dityrosine, protein carbonyl at amino acid level and lipid carbonyls).. Methods: Mass spectrometry (Ion-trap, MALDI ToF-ToF and GC-MS), spectroscopic ...
The possibility of employing cellular automata (CA) to model photo-induced oxidation processes in molecularly doped polymers is explored. It is demonstrated that the oxidation dynamics generated using CA models exhibit stretched-exponential behavior. This dynamical characteristic is in general agreement with an alternative analysis conducted using standard rate equations provided the molecular doping levels are sufficiently low to prohibit the presence of safe-sites which are impenetrable to dissolved oxygen. The CA models therefore offer the advantage of exploring the effect of dopant agglomeration which is difficult to assess from standard rate equation solutions. The influence of UV-induced bleaching or darkening upon the resulting oxidation dynamics may also be easily incorporated into the CA models and these optical effects are investigated for various photo-oxidation product scenarios. Output from the CA models is evaluated for experimental photo-oxidation data obtained from a series of hydrazone
Reduction/oxidation (Redox) reactions chemically convert hazardous contaminants to less toxic compounds that are less mobile and/or inert. Redox reactions involve the transfer of electrons from one compound to another. One compound is oxidized (loses electrons) and one is reduced (gains electrons). Oxidizing agents most commonly used for treatment of hazardous contaminants are ozone, hydrogen peroxide, hypochlorite, chlorine, and chlorine dioxide. The reducing agents most commonly used for treatment of hazardous waste are ferrous sulfate, sodium bisulfite, and sodium hydrosulfite. Experimental systems have been used to oxidize trichloroethylene (TCE) and perchloroethylene (PCE ...
The present invention relates to an integrated process and apparatus for supplying at least a portion of, or substantially all, or all of the reducing gas feedstock to a reduction reactor, such as a reactor for the direct reduction of iron, wherein the reducing gas contacts a feed material at a mean operating gas pressure and effects reduction of the feed material to provide a reduced product. The integrated process includes the production of a hydrogen-rich gas by the partial oxidation of a hydrocarbonaceous feedstock to produce a hydrogen-rich gas, which can also be referred to as a synthesis gas or syngas. The synthesis gas is at a pressure substantially greater than the mean operating gas pressure in the reduction reactor. The synthesis gas is expanded to lower its pressure to substantially the mean operating gas pressure in the DRI reduction reactor to thereby form the reducing gas feedstock at the pressure conditions used for the DRI reaction. The lower pressure reducing gas mixture generated by
TY - JOUR. T1 - Highly Efficient Catalysis of Preferential Oxidation of CO in H2-Rich Stream by Gold Single-Atom Catalysts. AU - Qiao, Botao. AU - Liu, Jiaxin. AU - Wang, Yang Gang. AU - Lin, Qingquan. AU - Liu, Xiaoyan. AU - Wang, Aiqin. AU - Li, Jun. AU - Zhang, Tao. AU - Liu, Jingyue. PY - 2015/11/6. Y1 - 2015/11/6. N2 - Preferential oxidation of CO (PROX) in H2-rich stream is critical to the production of clean H2 for the H2-based fuel cells, which provide clean and efficient energy conversion. Development of highly active and selective PROX catalysts is highly desirable but proved to be extremely challenging. Here we report that CeO2-supported Au single atoms (Au1/CeO2) are highly active, selective, and extremely stable for PROX at the PEMFC working temperature (μs 80 °C) with ,99.5% CO conversion over a wide temperature window, 70-120 °C (or 50-100 °C, depending on the Au loading). The high CO conversion realized at high temperatures is attributed to the unique property of single-atom ...
Under normal physiological conditions, ROS levels are low and ROS detoxification is easily managed by intrinsic antioxidant defence systems. In this context, ROS benefit neuronal health because of their central role in redox signalling. Redox-dependent signalling pathways are made up of redox-sensitive proteins that can undergo reversible oxidation or reduction reactions. The function of redox-sensitive proteins change depending on whether a protein is in its oxidized or reduced state. Thus ROS-RNS interaction influences protein signalling capacity in a redox-dependent manner. ROS and RNS play a key role in a variety of biologically important neural pathways including LTP (long-term potentiation), synaptic plasticity, neurogenesis, neuronal differentiation, apoptosis and the establishment of neuroprotective preconditioning [3,4]. Cellular signalling is also influenced by redox status at the transcriptional level, as numerous transcription factors are redox-sensitive, including NF-κB (nuclear ...
Im trying to increase my thickness uniformity in SiO2 deposition for a dry, high temperature oxidation process. My wafer profile is thin in the middle and thic
Despite recent advances in the field of vascular redox signalling in hypertension, it still remains unclear exactly how ROS cause vascular injury. We hypothesise that regulation of redox-sensitive protein tyrosine phosphatases (PTP) through oxidative modification, is impaired in hypertension. VSMC normotensive (NT) and hypertensive (HT) individuals were stimulated with AngII (10-7 M) and ET-1 (10-7 M). Irreversible oxidation of proteins and PTPs was assessed by oxyblot. Differential gel electrophoresis (DiGE) and CyDye thiol labelling were employed for screening of reversibly oxidised proteome. Irreversible protein oxidation was not affected by AngII or ET-1 in VSMCs from NT and HT subjects. Proteomic data, filtered for FC ,2, detected 2051 spots with 1899 (92.5%) being equally oxidised between NT and HT. In addition, oxidation of 57 (2.9%) spots was increased, while 95 (4.6%) were decreased in HT. Candidate proteins exhibiting consistent changes across three experimental replicates included ...
Purchase Thiol Redox Transitions in Cell Signaling, Part A, Volume 473 - 1st Edition. Print Book & E-Book. ISBN 9780123813459, 9780123813466
Our earlier experimental study has shown that exhaust unburnt hydrocarbon emissions from spark-ignition engines can be reduced effectively by using in-cylinder catalysts on the surface of the piston top-land crevice. In order to improve the understanding of the process and mechanism by means of which unburnt hydrocarbon emissions are reduced, a phenomenological mathematical model was developed for catalytic oxidation processes in the piston-ring-pack crevice.This paper describes in details the modelling of the processes of the gas flow, mass diffusion and reaction kinetics in the crevices. The flow in the crevices is assumed to be isothermal and at the temperature of the piston crown surface. The overall rate of reaction is calculated using expressions for mass diffusion for laminar flows in channels and a first-order Arrhenius-type expression for catalytic reaction kinetics of hydrocarbon oxidation over platinum.The model is capable of describing the time-dependent behaviour of the gas flow and ...
The Earths original atmosphere held very little oxygen. This began to change around 2.4 billion years ago when oxygen levels increased dramatically during what scientists call the Great Oxidation Event. The cause of this event has puzzled scientists, but researchers writing in Nature have found indications in ancient sedimentary rocks that it may have been linked to a drop in the level of dissolved nickel in seawater.. The Great Oxidation Event is what irreversibly changed surface environments on Earth and ultimately made advanced life possible, says research team member Dominic Papineau of the Carnegie Institutions Geophysical Laboratory. It was a major turning point in the evolution of our planet, and we are getting closer to understanding how it occurred.. The researchers, led by Kurt Konhauser of the University of Alberta in Edmonton, analyzed the trace element composition of sedimentary rocks known as banded-iron formations, or BIFs, from dozens of different localities around the ...
This thesis deals mainly with two oxidation reactions: water oxidation and aerobic oxidation, both of which have been applied in a biomimetic fashion. In the former reaction molecular oxygen is generated whereas in the latter it was used as terminal oxidant in oxidation reactions.. The first part of this thesis describes the synthesis of different ruthenium and manganese complexes that could potentially act as catalysts for water oxidation. This part includes a discussion of the stability and reactivity of a new manganese(III) amide-type complex, that has been used as a catalyst for both epoxidation of stilbene and alcohol oxidation.. The second part of this thesis discusses the synthesis of two new hybrid catalysts consisting of hydroquinone linked cobalt(II) salophen and cobalt(II) salmdpt, which have been used as oxygen-activating catalysts in aerobic oxidation reactions. The former catalyst was applied to the Pd-catalyzed reactions such as 1,4-diacetoxylation of cyclohexadiene whereas the ...
The reinvestigation of the kinetics of myeloperoxidase (MPO) activity with the use of NADPH as a probe has allowed us to determine the effects of H2O2, Cl- ion and pH on the MPO-dependent production of HOCl. The chlorination rate of NADPH did not depend on NADPH concentration and was entirely related to the rate of production of HOCl by MPO. The overall oxidation of NADPH occurred similarly in the absence of O2 and was insensitive to scavengers of the superoxide radical anion. Experiments performed on the direct oxidation of NADPH by MPO in the presence and the absence of H2O2 showed that neither the rate nor the stoichiometry of the reaction could interfere in the NADPH oxidation process involved in the steady-state chlorination cycle. The oxidation of NADPH was characterized by a decrease in the A339 of the reduced nicotinamide with the concomitant appearance of a new chomophore with absorbance maximum at 274 nm, characterized by isosbestic points at 300 and 238 nm. The reaction product did ...
Decreased Complete Oxidation Capacity of Fatty Acid in the Liver of Ketotic Cowsa - Dairy Cow;Ketosis, Liver;Fatty Acid Oxidation;
In this study, we provide the first evidence that the MTK1 SAPKKK serves as an oxidative stress sensor that perceives cellular redox states and converts them into intracellular signaling to regulate cell fate decisions such as cell death and cytokine production. This stress sensor is unique in that it does not simply detect intracellular oxidation events but it responds to coupled oxidation and reduction reactions, and it also acts as an effector to induce delayed and sustained activation of SAPK signaling through its C-terminal KD. We found that the three Cys residues (C163/C193/C218) in its N-terminal GBD were critical for the redox sensor function of MTK1. These residues are rapidly oxidized and then gradually reduced following oxidative stress exposure, and, of these residues, the redox regulation of C218 is essential for the activation of the KD. Therefore, the GBD of MTK1 not only binds to the GADD45 proteins to respond to GADD45-inducing stresses (e.g., DNA damage) but also perceives ...
If you have a question about this talk, please contact Dr Alex Archibald.. The phenomenon of air pollution is underpinned by a rich chemistry that is largely determined by the interplay between anthropogenic and biogenic emissions into the atmosphere. Central to this chemistry are the oxidation reactions of hydrocarbons, which play a pivotal role in determining the capacity of a hydrocarbon to pollute the air. However, quantitative and complete measurements of the mechanisms by which oxidation occurs are very uncommon, especially as a function of temperature.. A comprehensive study of one such mechanism, that of i-butanol with the OH radical, will be presented. In this example, multiple branching and sequential oxidation reactions lead to different end products that are determined by the initial site of OH attack. These branching ratios are found to exhibit temperature dependence, and therefore, under real-world conditions would lead to an end product distribution that changes according to both ...
A spectrophotometric investigation of oxidation of chondroitin-4-sulfate (CS) as a sustainable and biodegradable sulfated macromolecule by oxyanion permanganate ion as multi-equivalent oxidant in acid perchlorate solutions at a constant ionic strength of 2.0 mol dm-3 has been studied. The experimental results on the influence of the concentration of the reactants the reaction rates revealed first-order dependence in MnO4- , fractional second-order in [CS] and fractional first-order with respect to the hydrogen ion concentration. The hydrogen acid concentration dependence of the rate constants indicated that the oxidation rates were increased with increasing the acid concentration which means that the oxidation reaction is of acid-catalyzed nature. The oxidation of all other polysaccharides by this oxidant in acidic solutions indicated that the oxidation processes were proceeding throughout two distinct stages. The first stage was relatively slow, followed by a more fast reaction in the second
Reaction behavior of ferric oxide in system Fe2O3-SiO2Mar 01, 2016· The thermodynamic analyses and reductive sintering experimental results show that
Reaction behavior of ferric oxide in system Fe2O3-SiO2Mar 01, 2016· The thermodynamic analyses and reductive sintering experimental results show that
One way to quantify whether a substance is a strong oxidizing agent or a strong reducing agent is to use the oxidation-reduction potential or redox potential. Strong reducing agents can be said to have a high electron-transfer potential. Strong oxidizing agents have low electron-transfer potential. Oxidizing and reducing agents occur as couples, with a strong reducing agent coupled with a weak oxidizing agent and vice versa. Since these processes involve the transfer of electrons, the measurement of the resulting charge separation can be quantified in voltage measured between the couple and a standard hydrogen half-cell with 1 molar hydrogen and 1 atmosphere of hydrogen pressure on it. The redox potential of the hydrogen is zero at pH=0, but for tabulations a pH=7 is used for the hydrogen and under those conditions its redox potential is -0.421 volts. As a useful reference, the redox potentials of couples that commonly occur in biochemistry can give insight into their roles in biological energy ...
Get this from a library! Transformations of halogenated hydrocarbons : hydrolysis and redox processes. [N Lee Wolfe; Peter M Jeffers; Environmental Research Laboratory (Athens, Ga.)]
Achten, J., and A.E. Jeukendrup (2003). The effect of pre-exercise carbohydrate feedings on the intensity that elicits maximal fat oxidation. J. Sports Sci. 21:1017-1024.. Achten, J., M. Gleeson, and A. E. Jeukendrup (2002). Determination of the exercise intensity that elicits maximal fat oxidation. Med. Sci. Sports Exerc. 34:92-97.. Achten, J., M.C. Venables, and A.E. Jeukendrup (2003). Fat oxidation rates are higher during running compared with cycling over a wide range of intensities. Metabolism 52:747-752.. Burke, L.M., and J.A. Hawley (2018). Swifter, higher, stronger: Whats on the menu? Science 362:781-787.. Burke, L.M., M.L. Ross, L.A. Garvican-Lewis, M. Welvaert, I.A. Heikura, S.G. Forbes, J.G. Mirtschin, L.E. Cato, N. Strobel, A.P. Sharma, and J.A. Hawley (2017). Low carbohydrate, high fat diet impairs exercise economy and negates the performance benefit from intensified training in elite race walkers. J. Physiol. 595:2785-2807. Chrzanowski-Smith, O.J., R.M. Edinburgh, M.P. Thomas, N. ...
Understanding how oxidation of proteins leads to reversible alterations in protein function is relevant for proteins involved in cellular signaling processes, including protein tyrosine phosphatases (PTPs). Two groups, Salmeen et al. and van Montfort et al., show that PTP1B is reversibly oxidized by such chemicals as hydrogen peroxide or 2-phenyl-isoxazalidine-3,5-dione and forms a previously uncharacterized sulfenyl-amide because of oxidation of the catalytic site cysteine. Both groups analyzed the crystal structure of PTP1B after exposure to oxidizing conditions and identified the formation of the sulfenyl-amide, which caused large changes in the conformation of the active site. Salmeen et al. reported inhibition of substrate binding in the peroxide-exposed PTP1B, consistent with the structural changes blocking substrate recognition. This novel intermediate may effectively protect PTP1B from irreversible inactivation that would result from the formation of sulfinic or sulfonic acids.. A. ...
Cysteines play important roles in the biochemistry of many proteins. The high reactivity, redox properties, and ability of the free thiol group to coordinate metal ions designate cysteines as the amino acids of choice to form key catalytic components of many enzymes. Also, cysteines readily react with reactive oxygen and nitrogen species to form reversible oxidative thiol modifications. Over the last few years, an increasing number of proteins have been identified that use redox-mediated thiol modifications to modulate their function, activity, or localization. These redox-regulated proteins are central players in numerous important cellular processes. First aim of this study was to discover nitric oxide (NO) sensitive proteins in E. coli, whose redox-mediated functional changes might explain the physiological alterations observed in E. coli cells suffering from NO-stress. To identify E. coli proteins that undergo reversible thiol modifications upon NO-treatment in vivo, I applied a differential ...
Cancer can be viewed as a state in which the balance between cell proliferation and cell death aberrantly favors the former. We and others have discovered that the intracellular redox environment exerts a profound influence on the normal cellular processes that regulate the balance between proliferation and cell death, including DNA synthesis, enzyme activation, cell cycle progression, proliferation, differentiation, and apoptosis. In fact, it could be argued that redox homeostasis is central to the governance of cell fate. Unfortunately, molecular mechanisms mediating redox sensitivity and regulation within cells are still poorly defined. Current pharmacological methods to alter intracellular redox state are limited by (i) their inability to operate independent of global biochemical alterations and cellular toxicity, and (ii) the required significant manipulation of culture conditions that perturb intracellular homeostasis. Our genetic constructs overcome these limitations as they enable ...
Apoptosis is a regulated programme by which cells are induced to die in a manner which does not result in pathological inflammatory reactions, and involves dismantling of the cell into membrane-bound fragments that are removed by phagocytosis. This process is induced in order to remodel tissues and maintain homeostasis in cell numbers. Apoptosis may be induced via many pathways, many of which are redox-regulated, and is dysregulated in cancer cells, mainly due to mutational inactivation of certain pathways. Cancer cells also have a non-linear response to redox imbalance, a potentially exploitable characteristic for the therapeutic selective induction of apoptosis in cancer cells in mixed cell populations. Model cell culture systems are required for the selective toxicity testing of anti-cancer drugs, many of which work by inducing redox stress. In the current study, hydrogen peroxide was selected as the redox stress-inducing agent, and the test cells were an immortal, non-invasive breast ...
This process pertains to a achieving high on-stream time and maintaining the temperature and composition of the raw effluent gas stream from a partial oxidation gas generator being fed simultaneously with a stream of gaseous fuel and separate stream of liquid hydrocarbonaceous fuel. Two parallel oxygen streams equipped with flow transmitters and control valves are used to supply the oxygen associated with two separate and different fuel streams. Each stream of oxygen is controlled by an O2 /fuel ratio control so that if the flow rate of either stream of fuel or its related oxygen stream changes, the oxygen/carbon atomic ratio of the remaining O2 and fuel stream in the gasifier is maintained at a desired value. Further, if either fuel flow is stopped, its associated O2 flow will stop, but the remaining fuel stream and its associated O2 stream will continue to flow at the same rate with no change in the oxygen/fuel weight ratio. Complete shut down of the unit is thereby avoided. The quick raising of
They act as electron carriers and participates in oxidation-reduction reactions of reaction intermediates. (b) Calculate the ΔG0 for a 2 electron transfer between these two electron carriers. Faradays constant is 96.5kJ V-1 mole-1 . FAD can be reduced to FADH 2 through the addition of 2 H + and 2 e −.FADH 2 can also be oxidized by the loss of 1 H + and 1 e − to form FADH. The FAD form can be recreated through the further loss of 1 H + and 1 e −.FAD formation can also occur through the reduction and dehydration of flavin-N(5)-oxide. These redox (reduction-oxidation) reactions play a crucial role in energy generation. The reduction potential of FAD/FADH2 is -0.22 V and that of CoQ/CoQH2 is 0.06V. Using The Reduction Potential Chart Below, Prove That The Electrons Will Flow In The Direction Indicated, I.e, First From Succinate To FAD And Second, From FADH2 To DCPIP. FAD et NAD+ dans loxydation des lipides/respiration cellulaire ----- Bonjour à tous, Jaurais deux petites question ...
Oxidation-reduction (redox) reactions are among the most important and interesting chemical reactions that occur in aquatic environmental systems, which include soils, sediments, aquifers, rivers, lakes, estuaries, water treatment and distribution systems, etc. This volume provides a comprehensive overview of aquatic redox chemistry through chapters contributed by many of the leading investigators in the field.
The oxidation of dibenzoazepine derivatives has been proposed in the literature to lead to an intensively colored dimer, which is a product of a four-electron oxidation process [15]. Electrospray ionization MS spectra (Scheme 1, Fig. S2, Supporting Information) show the presence of molecular and characteristic fragmentation peaks for dimer 7: 557 (M-H), 279 (M-C19H23N2 monomer) m/z; dimer 8: 474 (MH+), 388 (M-C5H12N), 86 (M-C28H24N2) m/z; dimer 9: 388 (M+•) m/z; methyl derivative of dimer: 488 (MH+, low abundance) m/z; hydroxy derivative of imipramine: 297 (MH+, low abundance), 279 (M-OH), 86 (M-C14H13NO) m/z. The molecular and fragmentation peaks for imipramine (6) were as follows: 281 (MH+), 236 (M-C2H6N), 208 (M-C4H10N), 86 (M-C14H12N), 58 (M-C16H16N) m/z. A cleavage of the alkyl substituent, which leads to the formation of dimers 8 and 9, occurs at the stage of oxidation of the compound but is not due to the spontaneous degradation process because an analogous process does not occur in the ...
The low-temperature reaction of [CrCl3(thf)3] with LiC6H3Cl2-2,6 yields the organochromium(III) compound [Li(thf)4][CrIII(C6H3Cl2-2,6)4] (1) in 48% yield. The homoleptic, anionic species [CrIII(C6H3Cl2-2,6)4]− is electrochemically related to the neutral one [CrIV(C6H3Cl2-2,6)4] (2) through a reversible one-electron exchange process (E1/2 = 0.16 V, ΔEp = 0.09 V, ipa/ipc = 1.18). Compound 2 was isolated in 74% yield by chemical oxidation of 1 with [N(C6H4Br-4)3][SbCl6]. Attempts to prepare the salt [NBu4][CrIII(C6Cl5)4] (4) by direct arylation of [CrCl3(thf)3] with LiC6Cl5 in the presence of [NBu4]Br gave the organochromium(II) salt [NBu4]2[CrII(C6Cl5)4] (3) instead, as the result of a reduction process. The salt [NBu4][CrIII(C6Cl5)4] (4) was cleanly prepared by comproportionation of 3 and [CrIV(C6Cl5)4]. The reaction of [MoCl4(dme)] with LiC6Cl5 in Et2O solution proceeded with oxidation of the metal center to give the paramagnetic (S = 1/2), five-coordinate salt [Li(thf)4][MoVO(C6Cl5)4] (5). ...
To understand the benefits of antioxidants its important to know what an antioxidant does. An antioxidant is anything that can slow down or stop the oxidation process once it has started. The oxidation process is a chemical reaction that involves ...
TY - JOUR. T1 - Solubilities of CO2 and Redox Equilibria of Sb and As in NaO0.5-SbOm and NaO0.5-AsOm Melts. AU - Fujisawa, Toshiharu. AU - Yamauchi, Chikabumi. AU - Fukuyama, Hiroyuki. AU - Kato, Toru. AU - Ikitsu, Yasuaki. PY - 1992/1/1. Y1 - 1992/1/1. N2 - Solubilities of CO2and redox ratios of Sb and As (nSb3+/nSb5+, nAs3+/nAs5+, n: the number of moles) in NaO0.5-SbOmand NaO0.5AsOm melts were studied. The equilibrium measurements were conducted over the composition range of [formula omitted] under the partial pressures of CO2and O2of 0.01∼0.1 MPa and 0.005∼1000 Pa, respectively, at the temperatures of 1423 and 1523 K. Antimony exists in NaO0.5CO2SbOm melts not only in pentavalent (SbO43-) but also in trivalent (SbO2-) state, their relative proportions depending on the experimental conditions. The CO2solubility in the melts is, therefore, determined by the following reactions: [formula omitted] and [formula omitted]. Arsenic exists predominantly in the form of pentavalent anion (AsO43-) in ...
Chemically, oxidation is defined as the removal of electrons and reduction as the gain of electrons. Thus, oxidation of a molecule (the electron donor) is always accompanied by reduction of a second molecule (the electron acceptor). This principle of oxidation-reduction applies equally to biochemical systems and is an important concept underlying understanding of the nature of biologic oxidation. Note that many biologic oxidations can take place without the participation of molecular oxygen, for example, dehydrogenations. The life of higher animals is absolutely dependent upon a supply of oxygen for respiration, the process by which cells derive energy in the form of ATP from the controlled reaction of hydrogen with oxygen to form water. In addition, molecular oxygen is incorporated into a variety of substrates by enzymes designated as oxygenases; many drugs, pollutants, and chemical carcinogens (xenobiotics) are metabolized by enzymes of this class, known as the cytochrome P450 system. ...
Photosynthesis is a redox process both OXIDATION AND REDUCTION. Oxidation and reduction go hand in hand. Cellular respiration is a redox process too, both oxidation and reduction. so in Photosynthesis carbon dioxide (CO2) is reduced to form sugar (C6H12O6) while in respiration, sugar (C6H12O6) is oxidized to form carbon dioxide (CO2). ;) (Campbell, Biology sixth edition, pag, 110, Figure 7.4A and Figure 7.4B) Vete ...
A series of aluminum complexes containing the tridentate, redox-active ligand bis(3,5-di-tert-butyl-2-phenol)amine ([ONO]H3) in three different oxidation states were synthesized. The aluminum halide salts AlCl3 and AlBr3 were reacted with the doubly deprotonated form of the ligand to afford five-coordinate [ New Talent: Americas
This is an introduction to oxidation-reduction reactions, also known as redox reactions. Learn what redox reactions are and get examples.
TY - JOUR. T1 - Redox mechanism as alternative to ligand binding for receptor activation delivering disregulated cellular signals. AU - Nakashima, Izumi. AU - Pu, Mei Yi. AU - Nishizaki, Akira. AU - Rosila, Idris. AU - Ma, Li. AU - Katano, Yoshiaki. AU - Ohkusu, Kozo. AU - Rahman, S. M.Jamshedur. AU - Isobe, Ken Ichi. AU - Hamaguchi, Michinari. AU - Saga, Keisuke. PY - 1994/2/1. Y1 - 1994/2/1. N2 - Cross-linking with specific ligand is a general requirement for ordered activation of cell surface receptors. In this study we demonstrated a novel pathway for disregulated receptor activation through a redox mechanism. Treatment of murine thymocytes or spleen cells with thiol-reactive HgCl2, a known inducer of autoimmune proliferative lymphocyte disorders in rodents, was found to induce tyrosine phosphorylation of several cellular proteins, which was up to 100 times as extensive as that triggered by stimulation with antireceptor antibody or mitogen. Through the cross-linkage by thiol-reactive ...
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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