Bibliografie tematiche / Mediated oxidation

Letteratura scientifica selezionata sul tema "Mediated oxidation"

Autore: Grafiati

Pubblicato: 8 giugno 2024

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Articoli di riviste sul tema "Mediated oxidation":

Francioso, Antonio, Alessia Baseggio Conrado, Carla Blarzino, Cesira Foppoli, Elita Montanari, Simone Dinarelli, Alessandra Giorgi, Luciana Mosca e Mario Fontana. "One- and Two-Electron Oxidations of β-Amyloid25-35 by Carbonate Radical Anion (CO3•−) and Peroxymonocarbonate (HCO4−): Role of Sulfur in Radical Reactions and Peptide Aggregation". Molecules 25, n. 4 (20 febbraio 2020): 961. http://dx.doi.org/10.3390/molecules25040961.

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The β-amyloid (Aβ) peptide plays a key role in the pathogenesis of Alzheimer’s disease. The methionine (Met) residue at position 35 in Aβ C-terminal domain is critical for neurotoxicity, aggregation, and free radical formation initiated by the peptide. The role of Met in modulating toxicological properties of Aβ most likely involves an oxidative event at the sulfur atom. We therefore investigated the one- or two-electron oxidation of the Met residue of Aβ25-35 fragment and the effect of such oxidation on the behavior of the peptide. Bicarbonate promotes two-electron oxidations mediated by hydrogen peroxide after generation of peroxymonocarbonate (HCO4−, PMC). The bicarbonate/carbon dioxide pair stimulates one-electron oxidations mediated by carbonate radical anion (CO3•−). PMC efficiently oxidizes thioether sulfur of the Met residue to sulfoxide. Interestingly, such oxidation hampers the tendency of Aβ to aggregate. Conversely, CO3•− causes the one-electron oxidation of methionine residue to sulfur radical cation (MetS•+). The formation of this transient reactive intermediate during Aβ oxidation may play an important role in the process underlying amyloid neurotoxicity and free radical generation.

Nurgaziyeva, E. K., G. S. Tatykhanova, G. A. Mun, V. V. Khutoryanskiy e S. E. Kudaibergenov. "Oxidation of Cyclohexane Mediated with Gel-Immobilized Gold Nanoparticles". International Journal of Biology and Chemistry 8, n. 1 (2015): 61–66. http://dx.doi.org/10.26577/2218-7979-2015-8-1-61-66.

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Clemens, Dahn L., Carol A. Casey, Michael F. Sorrell e Dean J. Tuma. "Ethanol Oxidation Mediates Impaired Hepatic Receptor-Mediated Enocytosis". Alcoholism: Clinical and Experimental Research 22, n. 4 (giugno 1998): 778–79. http://dx.doi.org/10.1111/j.1530-0277.1998.tb03866.x.

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Rice-Evans, C., e E. Baysal. "Iron-mediated oxidative stress in erythrocytes". Biochemical Journal 244, n. 1 (15 maggio 1987): 191–96. http://dx.doi.org/10.1042/bj2440191.

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Erythrocytes subjected extracellularly to iron-mediated oxidant stress undergo haemoglobin oxidation and membrane damage, which can be modulated by maintaining the energy requirements of the cells. The results presented here suggest that a balance exists between the oxidation state of the haemoglobin and the oxidative deterioration of the membrane lipids, which is dependent on the metabolic state of the erythrocytes. These findings have important implications for thalassaemic erythrocytes that may be exposed to excess plasma iron levels, in which excessive membrane-bound iron in the form of haemichromes is a characteristic feature and in which cellular ATP levels are lowered.

Faisal, Muhammad, Mukhtiar Ahmed, Sarwat Hussain, Fayaz Ali Larik e Aamer Saeed. "Investigating the effectiveness of classical and eco-friendly approaches for synthesis of dialdehydes from organic dihalides". Green Processing and Synthesis 8, n. 1 (28 gennaio 2019): 635–48. http://dx.doi.org/10.1515/gps-2019-0034.

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Abstract Monoaldehydes and dialdehydes are parts of millions of compounds and are extremely versatile intermediates. For the synthesis of monoaldehydes, one impressive approach to date, because of its excellent selectivity, high yield and stability towards over-oxidation and over-reduction, is the oxidation of organic monohalides. Numerous monohalides oxidation based methodologies to afford monoaldehydes are disclosed in literature. In this research work, twelve well-known approaches (well-documented for synthesis of monoaldehydes from monohalides) are investigated for their effectiveness towards synthesis of organic dialdehydes from organic dihalides. The classical approaches under investigation include modified Sommelet oxidation, Kröhnke oxidation, sodium periodate-mediated oxidative protocol, manganese dioxide-based oxidative approach, Kornblum oxidation and Hass-Bender oxidation. The eco-friendly approaches under observation include periodic acid-based IL protocol, periodic acid in vanadium pentoxide-mediated IL method, hydrogen peroxide in vanadium pentoxide-based approach, hydrogen peroxide-mediated IL methodology, IBX-assisted IL protocol and bismuth nitrate-promoted IL technique. In this investigation yield, overoxidation, eco-friendliness, cost-effectiveness and recyclability are the main parameters which are under examination. Hopefully, this research will help chemists in carrying out routine operations in organic synthesis and will also be fruitful to select finest synthetic approach, develop further new transformational methodologies and improve current transformational approaches for the synthesis of dialdehydes.

Sequeira, C. A. C., D. M. F. Santos e P. S. D. Brito. "Mediated and non-mediated electrochemical oxidation of isopropanol". Applied Surface Science 252, n. 17 (giugno 2006): 6093–96. http://dx.doi.org/10.1016/j.apsusc.2005.11.028.

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Miller, D. G., e D. D. M. Wayner. "Electrode-mediated Wacker oxidation of cyclic and internal olefins". Canadian Journal of Chemistry 70, n. 9 (1 settembre 1992): 2485–90. http://dx.doi.org/10.1139/v92-314.

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An improved method for the electrode-mediated oxidations of olefins by palladium(II) is described. Current efficiencies from 80% to 95% were obtained in oxidations of 1-decene, styrene, trans-2-octene, and cyclohexene in which perchloric acid was added to a chloride-free solution of a palladium(II) acetate catalyst. The palladium(0) was reoxidized to palladium(II) by reaction with catalytic amounts of benzoquinone, which was, in turn, regenerated by anodic oxidation. Addition of varying amounts of perchloric acid did not affect the current efficiency but accelerated the oxidation reaction, up to a concentration of approximately 0.15 M. The current efficiency remained high (>80%) over the course of the electrode-mediated oxidations of 1-decene, trans-2-octene, and cyclohexene. At the end of the reactions, when the substrate was depleted, a drastic decrease in the current was observed, indicating that the catalytic cycle leading to product was primarily responsible for the electrochemical reaction. It also was shown that the rates of the electrochemical reactions were generally slower than those of homogeneous reactions in which a stoichiometric amount of benzoquinone was used, indicating that the electrochemical regeneration of benzoquinone was mass transport limited at the highest concentrations of perchloric acid. This is in contrast to other reports in the literature that suggested that the homogeneous (non-electrochemical) reactions were actually slower. Reasons for the discrepancy between these results are discussed.

Tribble, Diane L., Berbie M. Chu, Gerri A. Levine, Ronald M. Krauss e Elaine L. Gong. "Selective Resistance of LDL Core Lipids to Iron-Mediated Oxidation". Arteriosclerosis, Thrombosis, and Vascular Biology 16, n. 12 (dicembre 1996): 1580–87. http://dx.doi.org/10.1161/01.atv.16.12.1580.

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Although the nature and consequences of oxidative changes in the chemical constituents of low density lipoproteins (LDLs) have been extensively examined, the physical dynamics of LDL oxidation and the influence of physical organization on the biological effects of oxidized LDLs have remained relatively unexplored. To address these issues, in the present studies we monitored surface- and core-specific peroxidative stress relative to temporal changes in conjugated dienes (CDs), particle charge (an index of oxidative protein modification), and LDL-macrophage interactions. Peroxidative stress in LDL surface and core compartments was evaluated with the site-specific, oxidation-labile fluorescent probes parinaric acid (PnA) and PnA cholesteryl ester (PnCE), respectively. When oxidation was initiated by Cu 2+ , oxidative loss of the core probe (PnCE) closely followed that of the surface probe (PnA), as indicated by the time to 50% probe depletion (t 1/2 ; 15.5±7.8 and 30.4±12 minutes for PnA and PnCE, respectively). Both probes were more resistant in LDL exposed to Fe 3+ (t 1/2 , 53.2±8.1 and 346.7±155.4 minutes), although core probe resistance was much greater with this oxidant (PnCE t 1/2 /PnA t 1/2, 5.8 vs 2.0 for Cu 2+ ). Despite differences in the rate and extent of oxidative changes in Cu 2+ - versus Fe 3+ -exposed LDLs, PnCE loss occurred in close correspondence with CD formation and appeared to precede changes in particle charge under both conditions. Exposure of LDLs to hemin, a lipophilic Fe 3+ -containing porphyrin that becomes incorporated into the LDL particle, resulted in rapid loss of PnCE and simultaneous changes in particle charge, even at concentrations that yielded increases in CDs and thiobarbituric acid–reactive substances similar to those obtained with free Fe 3+ . These results suggest that oxidation of the LDL hydrophobic core occurs in conjunction with accelerated formation of CDs and may be essential for LDL protein modification. In accordance with the known effects of oxidative protein modifications on LDL receptor recognition, exposure of LDLs to Cu 2+ and hemin but not Fe 3+ produced particles that were readily processed by macrophages. Thus, the physical site of oxidative injury appears to be a critical determinant of the chemical and biological properties of LDLs, particularly when oxidized by Fe 3+ .

Hu, Jianan, Yun Huang, Minru Xiong, Shafei Luo, Yong Chen e Yuanjian Li. "The Effects of Natural Flavonoids on Lipoxygenase-Mediated Oxidation of Compounds with a Benzene Ring Structure—A New Possible Mechanism of Flavonoid Anti-Chemical Carcinogenesis and Other Toxicities". International Journal of Toxicology 25, n. 4 (luglio 2006): 295–301. http://dx.doi.org/10.1080/10915810600746122.

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Numerous studies have strongly suggested that flavonoids exhibit antimutagenic, anticarcinogenic, antiallergic, and anti-inflammatory properties, but the mechanism is still far from clear. In this study, the effect of natural flavonoid compounds, such as green tea polyphenol, epigallocatechin gallate, quercetin, and rutin on lipoxygenase-mediated co-oxidation of guaiacol, benzidine, paraphenylenediamine, and dimethoxybenzidine was investigated. Green tea polyphenol, epigallocatechin gallate, quercetin, and rutin can reduce the co-oxidation reaction speed of tested compounds mediated by soybean lipoxygenase and the production of oxidative products and free radical intermediates. Their median inhibition concentrations on guaiacol oxidation mediated by soybean lipoxygenase were 8.22 mg·L−1, 17.8 μmol·L−1, 41.5 μmol·L−1, and 46.3 μmol·L−1, respectively. These were all significantly lower than glutathione, dithiothreitol, butylated hydroxyanisole and gossypol. The data collected in this study suggest that flavonoids may have an anticarcinogenicity and antitoxicity effect through inhibition of oxidative activation.

Luna, Carolina, e Mario Estévez. "Oxidative damage to food and human serum proteins: Radical-mediated oxidation vs. glyco-oxidation". Food Chemistry 267 (novembre 2018): 111–18. http://dx.doi.org/10.1016/j.foodchem.2017.06.154.

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Tesi sul tema "Mediated oxidation":

Škrabalová, Lada. "Hemoglobin-mediated oxidation of marine liposomes". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2012. http://www.nusl.cz/ntk/nusl-216833.

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Cílem této práce bylo studium mechanismu oxidace lipidů katalyzované hovězím methemoglobinem a zhodnocení účinků různých experimentálních podmínek a antioxidantů (EDTA, askorbová kyselina, kávová kyselina, a-tokoferol, d-tokoferol, astaxanthin a L-askorbyl-6-palmitát) na methemoglobinem zprostředkovanou oxidaci lipidů v modelovém systému liposomů připravených z fosfolipidů. K monitorování oxidace lipidů při pH 5,5 a teplotě 30 °C bylo použito spotřeby kyslíku. Pro zhodnocení antioxidační aktivity v modelovém systému liposomů se ukázaly být důležitými faktory typ prooxidantu a koncentrace prooxidantu a antioxidantu. Dalšími důležitými faktory jsou struktura molekuly antioxidantu, jeho hydrofilita/lipofilita a umístění v systému. Všechny testované antioxidanty ve všech koncentracích (kromě koncentrace 0.1 % astaxanthinu and 0.1 % askorbyl palmitátu) inhibovaly oxidaci vyvolanou methemoglobinem. Účinnost antioxidantu stoupala s jeho zvyšující se koncentrací. Koncentrace 0.1 % astaxanthinu neměla žádný vliv na oxidaci liposomů. Koncentrace 0.1 % askorbyl palmitátu měla prooxidační efekt, který lze vysvětlit prooxidačním působením radikálu askorbylu, který může urychlit štěpení hydroperoxidů. Volné železo uvolněné z methemoglobinu se podílelo jen velmi málo na oxidaci liposomů, zatímco část prooxidační aktivity methemoglobinu byla přisouzena tvorbě singletového kyslíku (methemoglobin jako fotosenzitizátor). Antioxidační aktivita astaxanthinu, askorbyl palmitátu a tokoferolu byla z části přisouzena schopnosti zhášet singletový kyslík. Ovšem hlavním prooxidačním mechanismem methemoglobinu se ukázal být rozklad lipidových hydroperoxidů, tvorba volných radikálů a hypervalentních forem hemoglobinu. EDTA utlumila oxidaci liposomů díky chelataci přechodných kovů obsažených v liposomech a chelataci volného železa přítomného v methemoglobinovém roztoku. Velmi důležitým antioxidačním mechanismem (který vykazují askorbyl palmitát, askorbová a kávová kyselina) se ukázala být redukce hypervalentních forem hemoglobinu. Askorbová kyselina, kávová kyselina, tokoferoly a astaxanthin inhibovaly methemoglobinem zprostředkovanou oxidaci lipidů odstraňováním volných radikálů. Při použití peroxidu vodíku nebyl pozorován žádný vliv na oxidaci liposomů vyvolanou methemoglobinem. Působení vysoké teploty (tepelná denaturace) mírně utlumilo oxidaci. Významná inhibice oxidace byla pozorována u liposomů obsahujících TPP (triphenylphosphin), což značí, že je methemoglobinem vyvolaná oxidace liposomů závislá na přítomnosti již vzniklých lipidových peroxidů. Výsledky této práce přispívají k hlubšímu pochopení prooxidačních a antioxidačních mechanismů a faktorů, které ovlivňují oxidaci liposomálních roztoků, buněčných membrán a emulzí typu olej ve vodě stabilizovaných fosfolipidy.

Wood, Geoffrey Paul Farra. "Theoretical Investigations of Radical-Mediated Protein Oxidation". Thesis, The University of Sydney, 2006. http://hdl.handle.net/2123/1413.

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This thesis primarily details the application of high-level ab initio quantum chemistry techniques in order to understand aspects of free-radical mediated protein oxidation. Traditionally, product analysis and electron paramagnetic resonance (EPR) spectroscopy are the primary means for elucidating the chemistry of protein oxidation. However, in experiments involving relatively small proteins reacting with a controlled radical-flux, a vast array of compounds can be produced, which are often difficult to analyse. Quantum chemical techniques on the other hand, can calculate the properties of any particular species directly, without suffering from the problems associated with experiment, such as side-reactions and chain processes. The results presented in this thesis are aimed at elucidating mechanistic details of protein oxidation, which might otherwise be difficult to probe experimentally. Chapter 1 gives an overview of the free-radical hypothesis of disease and ageing. Protein-derived radicals can undergo a variety of reactions, with the particular reaction that occurs depending on numerous aspects. Many types of reactions have been identified through radiolysis experiments of amino acids, and these are detailed in this chapter. In addition, the key reactive species are characterized and their different chemistries explained. Chapter 2 details the theoretical tools used throughout this thesis. Species with unpaired electrons (radicals) present unique problems for quantum chemistry to handle, thus an appropriate choice of theoretical technique is needed. The approach taken in this thesis is to use high-level compound methods, many of which have been directly formulated to give improved results for radical species, to provide benchmark quality results by which other less demanding techniques can be assessed. During the course of this study, it became apparent there was a void in the armoury of tools that could be used for the theoretical chemistry calculations. Chapter 3 details the formulation of a new tool in an attempt to fill this gap. Historically, the formulation of this new procedure came after much of the work in this thesis had been carried out. Thus, for the study of many of the reactions of this thesis the new method has not been used. However, it is most appropriate to place its formulation after summarizing the current status of techniques in common use today. Chapters 4 and 5 detail computations carried out on models of peptides containing backbone carbon- and nitrogen-centered radicals. A number of different theoretical techniques are used in these chapters, ranging from the highly accurate and computationally intensive to the less reliable and less demanding. The highly accurate techniques are used to gauge the accuracy of the other less demanding theoretical techniques so that the latter can be used with confidence in larger systems. Not only is the choice of theoretical technique important but also the judicious choice of model is essential. With this in mind, models are incrementally built until convergence of the particular property of interest is reached. Chapters 6 and 7 detail the calculations of Î²-scission reactions of alkoxyl radicals, which are a particular class of reaction known to occur on peptide backbones. Alkoxyl radicals are particularly difficult for theory to describe correctly. Therefore, Chapter 6 extensively assesses and then identifies the theoretical methods needed to portray them. Chapter 7 uses the techniques identified in the previous chapter in order to predict how the preference for a particular type of Î²-scission reaction changes.

Wood, Geoffrey Paul Farra. "Theoretical Investigations of Radical-Mediated Protein Oxidation". University of Sydney, 2006. http://hdl.handle.net/2123/1413.

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Doctor of Philosophy (PhD)
This thesis primarily details the application of high-level ab initio quantum chemistry techniques in order to understand aspects of free-radical mediated protein oxidation. Traditionally, product analysis and electron paramagnetic resonance (EPR) spectroscopy are the primary means for elucidating the chemistry of protein oxidation. However, in experiments involving relatively small proteins reacting with a controlled radical-flux, a vast array of compounds can be produced, which are often difficult to analyse. Quantum chemical techniques on the other hand, can calculate the properties of any particular species directly, without suffering from the problems associated with experiment, such as side-reactions and chain processes. The results presented in this thesis are aimed at elucidating mechanistic details of protein oxidation, which might otherwise be difficult to probe experimentally. Chapter 1 gives an overview of the free-radical hypothesis of disease and ageing. Protein-derived radicals can undergo a variety of reactions, with the particular reaction that occurs depending on numerous aspects. Many types of reactions have been identified through radiolysis experiments of amino acids, and these are detailed in this chapter. In addition, the key reactive species are characterized and their different chemistries explained. Chapter 2 details the theoretical tools used throughout this thesis. Species with unpaired electrons (radicals) present unique problems for quantum chemistry to handle, thus an appropriate choice of theoretical technique is needed. The approach taken in this thesis is to use high-level compound methods, many of which have been directly formulated to give improved results for radical species, to provide benchmark quality results by which other less demanding techniques can be assessed. During the course of this study, it became apparent there was a void in the armoury of tools that could be used for the theoretical chemistry calculations. Chapter 3 details the formulation of a new tool in an attempt to fill this gap. Historically, the formulation of this new procedure came after much of the work in this thesis had been carried out. Thus, for the study of many of the reactions of this thesis the new method has not been used. However, it is most appropriate to place its formulation after summarizing the current status of techniques in common use today. Chapters 4 and 5 detail computations carried out on models of peptides containing backbone carbon- and nitrogen-centered radicals. A number of different theoretical techniques are used in these chapters, ranging from the highly accurate and computationally intensive to the less reliable and less demanding. The highly accurate techniques are used to gauge the accuracy of the other less demanding theoretical techniques so that the latter can be used with confidence in larger systems. Not only is the choice of theoretical technique important but also the judicious choice of model is essential. With this in mind, models are incrementally built until convergence of the particular property of interest is reached. Chapters 6 and 7 detail the calculations of Î²-scission reactions of alkoxyl radicals, which are a particular class of reaction known to occur on peptide backbones. Alkoxyl radicals are particularly difficult for theory to describe correctly. Therefore, Chapter 6 extensively assesses and then identifies the theoretical methods needed to portray them. Chapter 7 uses the techniques identified in the previous chapter in order to predict how the preference for a particular type of Î²-scission reaction changes.

Hersey, Michelle. "Oxidation of Arsenite Via Chelator-mediated Fenton Systems". Fogler Library, University of Maine, 2006. http://www.library.umaine.edu/theses/pdf/HerseyMX2006.pdf.

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Probert, Gareth David. "The zirconocene-mediated synthesis of amines". Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242623.

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Henderson, William Howell. "Palladium-Mediated C-H Activations". The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1318003095.

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Wright, Adam. "Investigations of singlet oxygen-mediated amino acid, peptide and protein oxidation". Thesis, The University of Sydney, 2002. https://hdl.handle.net/2123/27830.

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Crosby, Natasha M. "The role of oxidation in hyperglycemia-mediated erythrocyte phospholipid asymmetry". [Bloomington, Ind.] : Indiana University, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3344761.

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Thesis (Ph. D.)--Indiana University, Dept. of Biology, 2009.
Title from PDF t.p. (viewed Oct. 8, 2009). Source: Dissertation Abstracts International, Volume: 70-02, Section: B, page: 0830. Adviser: David L. Daleke.

Kapinga, Sarah Kasangana. "Organic binder mediated Co3O4/TiO2 heterojunction formation for heterogeneous activation of Peroxymonosulfate". Thesis, Cape Peninsula University of Technology, 2019. http://hdl.handle.net/20.500.11838/2811.

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Thesis (Master of Engineering in Chemical Engineering)--Cape Peninsula University of Technology, 2019.
A shortage of water has resulted in the need to enhance the quality of wastewater that is released into the environment. The advanced oxidation process (AOP) using heterogeneous catalysis is a promising treatment process for the management of wastewater containing recalcitrant pollutants as compared to conventional processes. As AOP is a reliable wastewater treatment process, it is expected to be a sustainable answer to the shortage of clean water. AOP using heterogeneous catalysis based on Co3O4 particles and PMS, in particular has been found to be a powerful procedure for the degradation and mineralization of recalcitrant organic contaminants. In addition, due to the growing application of Co3O4 in lithium batteries, large quantities of these particles will be recovered as waste from spent lithium batteries, so there is a need to find a use for them. Although this method has received some promising feedback, challenges still need to be addressed, such as the toxicity of cobalt particles, the poor chemical and thermal stability and particle aggregation, and the prompting of lower catalytic efficiency in long haul application. Furthermore, the removal of the catalyst after the treatment of pollutants is also an issue. In order to be applicable, a novel catalyst must be produced requiring the combination of Co3O4 with a support material in order to inhibit cobalt leaching and generate better particle stability. From the available literature, TiO2 was found to be the best support material because it not only provides a large surface area for well dispersed Co3O4, but it also forms strong Co-O-Ti bonds which greatly reduced cobalt leaching as compared to other support materials. Moreover, it also greatly encourages the formation of surface Co–OH complexes, which is considered a crucial step for PMS activation. Therefore, the issues cited above could be avoided by producing a Co3O4/TiO2 heterojunction catalyst.

Han, Hyungjin Civil &amp Environmental Engineering Faculty of Engineering UNSW. "Mechanisms and modelling of sonochemically-mediated free radical degradation of contaminants". Awarded by:University of New South Wales. Civil & Environmental Engineering, 2009. http://handle.unsw.edu.au/1959.4/43485.

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Hazardous and recalcitrant pollutants in the environments have led to a great many environmental issues these days. Many researchers have focused on the approaches to treatment of these pollutants which contaminate environments such as soil, surface and groundwater. As an advanced oxidation processes (AOPs), sonolysis which is the oxidation technology involving the use of ultrasonic irradiation, has proven to be successful for the treatment and remediation of contaminated environments. In this thesis, hydrogen peroxide formation and formic acid degradation by ultrasonic irradiation of well-characterised solutions are described under various conditions in order to determinate reaction mechanism by which peroxide degradation and contaminant degradation occur. The effect of gas properties and frequency on hydrogen peroxide and formic acid degradation are examined. Experimental results obtained are analyzed in light of the reactions occurring. Successful mathematical modeling of the result s obtained confirms that, for the most part, hydrogen peroxide and formic degradation occur by free radical generation within bubbles with subsequent transfer of these radicals to the bubble-water interface where the majority of the degradation occurs. The effect of Fe(II) addition which can lead to Fenton reactions in the bulk solution are also investigated. Experimental and model results show that the heterogeneous reactions can enhance the degradation of formic acid in the presence of Fe(II). Oxidation of phenol by ultrasonic irradiation under a variety of initial conditions and solution environments is also described and validated by a simple kinetic model. The model developed will be useful for improving our understanding of free radicals behaviour and the interplay between free radical generation and contaminant degradation.

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Libri sul tema "Mediated oxidation":

Davies, M. J. Radical-mediated protein oxidation: From chemistry to medicine. Oxford: Oxford University Press, 1997.

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T, Hancock John, a cura di. Redox-mediated signal transduction: Methods and protocols. New York, NY: Humana Press, 2008.

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Luthra, Anchla. Evidence of peroxynitrite-mediated oxidative cell injury in the lateral geniculate nucleus in experimental glaucoma. Ottawa: National Library of Canada, 2002.

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Montana State University Keystone Symposium (1st 1991 Big Sky, Mont.). The molecular basis of oxidative damage by leukocytes. Boca Raton: CRC Press, 1992.

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Matsushima, Danielle Erina. 3-Phosphoinositide-dependent kinase-1 (PDK1)-mediated signaling regulates hematopoietic stem cell (HSC) quiesence by governing the oxidative response. [New York, N.Y.?]: [publisher not identified], 2016.

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Hancock, John T. Redox-Mediated Signal Transduction: Methods and Protocols. Humana Press, 2011.

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Conway, Myra, e John T. Hancock. Redox-Mediated Signal Transduction: Methods and Protocols. Springer, 2019.

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Phan, Thuy N. Mechanistic studies of metal oxide mediated oxidation via kinetic isotope analysis of pentamethylcyclopentadienyl rhenium diolate cycloreversion. 1993.

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Gray, Thomas James. Mediated oxidations of insulin, sulfur-containing amino acids and related compounds at a mixed-valence ruthenium cyanide electrode. 1990.

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Broderick, William E. Synthetic utility of Chromium (II)/(III) and Cobalt (II)/(III) redox chemistry mediated by coordinated ligands. 1986.

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Capitoli di libri sul tema "Mediated oxidation":

Stadtman, Earl R. "Free Radical Mediated Oxidation of Proteins". In Free Radicals, Oxidative Stress, and Antioxidants, 51–64. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4757-2907-8_5.

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Glover, V., e M. Sandler. "Monoamine oxidase-mediated activation of MPTP and related compounds". In N-Oxidation of Drugs, 357–69. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3112-4_21.

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Moan, Natacha, Frédérique Tacnet e Michel B. Toledano. "Protein-Thiol Oxidation, From Single Proteins to Proteome-Wide Analyses". In Redox-Mediated Signal Transduction, 175–92. Totowa, NJ: Humana Press, 2008. http://dx.doi.org/10.1007/978-1-59745-129-1_13.

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Matano, Yoshihiro. "Pentavalent Organobismuth Reagents in Organic Synthesis: Alkylation, Alcohol Oxidation and Cationic Photopolymerization". In Bismuth-Mediated Organic Reactions, 19–44. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/128_2011_167.

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Ziffer, Herman, Yulin Hu e Yuming Pu. "Beauveria Sulfurescens Mediated Oxidation of Dihydroartemisinin Derivatives". In Microbial Reagents in Organic Synthesis, 361–73. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2444-7_29.

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Hu, Shanghui, Wei Gao, Rajesh Kumar, Richard A. Gross, Qu-Ming Gu e H. N. Cheng. "Lipase-Mediated Selective TEMPO Oxidation of Hydroxyethylcellulose". In ACS Symposium Series, 253–64. Washington, DC: American Chemical Society, 2002. http://dx.doi.org/10.1021/bk-2003-0840.ch021.

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Fliss, H., M. Masika, D. W. Eley e B. Korecky. "Oxygen Radical Mediated Protein Oxidation in Heart". In Oxygen Radicals in the Pathophysiology of Heart Disease, 71–90. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4613-1743-2_6.

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Panizza, Marco. "Organic Pollutants, Direct and Mediated Anodic Oxidation". In Encyclopedia of Applied Electrochemistry, 1424–28. New York, NY: Springer New York, 2014. http://dx.doi.org/10.1007/978-1-4419-6996-5_126.

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Sayre, Lawrence M., Wei Tang, K. Veera Reddy e Durgesh Nadkarni. "Copper-Mediated Nitrogen Ligand Oxidation and Oxygenation". In Bioinorganic Chemistry of Copper, 236–48. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-6875-5_19.

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Maki, Toshihide, Kazuhiro Fukae, Hitomi Harasawa, Takahiro Ohishi e Yoshihiro Matsumura. "Electrochemical Oxidation of Diols Mediated by Organotin Compounds". In Novel Trends in Electroorganic Synthesis, 135–36. Tokyo: Springer Japan, 1998. http://dx.doi.org/10.1007/978-4-431-65924-2_40.

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Atti di convegni sul tema "Mediated oxidation":

Juodkazis, Kęstutis, Jurga Juodkazytė, Benjaminas Šebeka e Saulius Juodkazis. "Reversible hydrogen evolution and oxidation mediated by molecular ion". In SPIE Solar Energy + Technology, a cura di Yosuke Kanai e David Prendergast. SPIE, 2013. http://dx.doi.org/10.1117/12.2023294.

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Sanmartín-Matalobos, Jesús, Lucía Briones-Miguéns, Ana García-Deibe, Matilde Fondo e Concepcion González-Bello. "A convenient Pd-mediated oxidation of 4-methylbenzyl alcohol". In The 17th International Electronic Conference on Synthetic Organic Chemistry. Basel, Switzerland: MDPI, 2013. http://dx.doi.org/10.3390/ecsoc-17-a012.

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Undeland, Ingrid. "Strategies to prevent hemoglobin-mediated lipid oxidation in fish". In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/trvy8914.

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During the last 20 years, numerous studies have revealed how hemoglobin (Hb) strongly controls development of lipid oxidation in fish muscle; more so than the total lipid content or the relative amount of polyunsaturated fatty acids. In Chalmers, three main routes have been explored to combat Hb-mediated lipid oxidation in fish muscle; (i) preventing lysis of the red blood cells (RBC), (ii) removing Hb during processing, or (iii), introducing natural antioxidants. Key results from these strategies will be revealed. In (i), which is mainly applicable to very early steps of the fish process chain, we have found for example that avoiding osmotic or mechanic pressure as well as temperature raises keeps the RBC intact. Important RBC-stabilizing factors were also identified in blood plasma of herring and trout. In terms of Hb-removal, washing or pH-shift processing of different types of fish raw materials have been studied. Among findings are that repeated washing of fish mince (3Ã—3 volumes), e.g. in surimi production, can remove nearly 85% heme and yield relatively stable minces. On the other hand, limited washing (1Ã—1 volumes) destabilizes fish mince despite >60% heme removal, pointing at wash-out of antioxidants counteracting the effect of Hb removal. Work with antioxidants has been done both in simpler models such as washed fish mince and with more complex systems as filleting rest raw materials. Particularly interesting results have been found when using bladderwrack (Fucus vesiculosus) or rosemary extracts as well as grape or lingonberry press cakes. Extracts/solutions provides the possibility to apply antioxidants onto the surface of intact fish tissue via dipping or incubation treatments which is easy to implement in industry. The solid materials can on the other hand be co-processed with fish (rest)raw materials proving a sustainable concept to valorize different food side streams while at the same time preventing oxidation.

Sanmartín-Matalobos, Jesús, Lucía Briones-Miguéns, Cristina Portela-García, Ana García-Deibe, Matilde Fondo, Emilio Lence e Concepcion González-Bello. "Computational studies on the palladium-mediated oxidation of methanol to formaldehyde". In The 17th International Electronic Conference on Synthetic Organic Chemistry. Basel, Switzerland: MDPI, 2013. http://dx.doi.org/10.3390/ecsoc-17-e010.

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Wu, Haizhou, Jie Yin e Mark Richards. "Inhibitory Mechanisms of Quercetin Against Hemoglobin-mediated Lipid Oxidation in Washed Muscle Model". In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/ituo9388.

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Lipid oxidation in fresh and further processed meat facilitates quality deterioration during storage, including loss of color, flavor, and in some cases nutritional value. Flavonoids are found ubiquitously in plants as a member of polyphenolic compounds and have received considerable attention for their antioxidant properties. Numerous studies have demonstrated that free radical scavenging and metal chelation could be the key factors responsible for the antioxidative activities of flavonols. In our previous work, a fraction isolated from cranberry juice powder was an effective inhibitor of lipid oxidation in mechanically separated turkey (MST) and washed cod muscle. The compound responsible for the inhibitory activity was then identified as quercetin. However, the mechanisms by which quercetin inhibits lipid oxidation due to heme proteins present in muscle foods has received little attention. With this background, we studied the antioxidant effect of quercetin on hemoglobin(Hb)-mediated lipid oxidation and the mechanisms involved in washed cod muscle model. Quercetin strongly inhibited Hb-mediated lipid oxidation in washed muscle. Quercetin showed effective hydroxyl radical scavenging ability similar to butylated hydroxytoluene (BHT). Quercetin reduced metHb resulting in formation of oxyHb. Bound quercetin decreased heme dissociation from metHb. Conversion to oxyHb and decreased heme dissociation represent routes to limit Hb-mediated lipid oxidation. Electrospray ionization mass spectrometry (ESI-MS) indicated one molecule of quercetin was covalently bound to Hb α-chain. Quercetin quinone docked 3.3 Å from the thiol of αCys(H15) but not near any other Cys residues of turkey Hb. At the docking site, hydrogen bonding between quercetin quinone and amino acids of α- and β-chain was demonstrated. This represents a path by which quercetin became covalently bound to α-chain. Molecular docking of heme proteins to polyphenols provides a template to better understand antioxidant interactions in muscle foods.

Jung, Kwang Hwa, Jun Hyoung Park, Tirupataiah Sirupangi, Sajna Vithayathil, Lee-Jun Wong e Benny A. Kaipparettu. "Abstract 1507: Fatty acid oxidation mediated autophagy regulation in triple negative breast cancer". In Proceedings: AACR Annual Meeting 2017; April 1-5, 2017; Washington, DC. American Association for Cancer Research, 2017. http://dx.doi.org/10.1158/1538-7445.am2017-1507.

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Haas, Lisa D., Eric E. Roden, Matthew Ginder-Vogel e James J. Zambito. "MICROBIALLY-MEDIATED PYRITE OXIDATION AT CIRCUMNEUTRAL PH IN SANDSTONES OF TREMPEALEAU COUNTY, WI". In GSA Annual Meeting in Phoenix, Arizona, USA - 2019. Geological Society of America, 2019. http://dx.doi.org/10.1130/abs/2019am-339140.

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Gu, L., J. L. Casey, D. Davis e A. B. Carter. "MCU Modulates Transcriptional Network for PGC-1a-Mediated Fatty Acid Oxidation During Pulmonary Fibrosis". In American Thoracic Society 2019 International Conference, May 17-22, 2019 - Dallas, TX. American Thoracic Society, 2019. http://dx.doi.org/10.1164/ajrccm-conference.2019.199.1_meetingabstracts.a7223.

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Zhang, Han, Hao Liu, Xiaofang Wan e Jianhua Cheng. "TEMPO-mediated oxidation of Flammulina velutipes mycelia for fabrication of transparent tension chitin membranes". In 2018 8th International Conference on Manufacturing Science and Engineering (ICMSE 2018). Paris, France: Atlantis Press, 2018. http://dx.doi.org/10.2991/icmse-18.2018.112.

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Rokhima, Ummu, Henry Setiyanto, Muhammad Zulfikar, Vienna Saraswaty e Nandang Mufti. "Study of Methylene Blue Degradation Using Mediated Electrochemical Oxidation With Ce (IV) Ions: Effect of Supporting Electrolyte, Ce (III) Concentration, and Oxidation Potential". In Proceedings of the 7th Mathematics, Science, and Computer Science Education International Seminar, MSCEIS 2019, 12 October 2019, Bandung, West Java, Indonesia. EAI, 2020. http://dx.doi.org/10.4108/eai.12-10-2019.2296387.

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Rapporti di organizzazioni sul tema "Mediated oxidation":

Riveros, P., E. W. Wong, D. J. MacKinnon, K. E. Haque, E. A. Giziwicz e P. D. Kondos. Chloride mediated electro-oxidation of cyanide. Natural Resources Canada/CMSS/Information Management, 1995. http://dx.doi.org/10.4095/327779.

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Haque, K. E., e O. Dinardo. Thiosalts removal from mine/mill effluent by halide mediated electro-oxidation. Natural Resources Canada/CMSS/Information Management, 1996. http://dx.doi.org/10.4095/327780.

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Peter Dedon. Radiation Research Symposium: Chemistry and Biology of Radical-mediated Deoxyribose Oxidation in DNA. Office of Scientific and Technical Information (OSTI), ottobre 2005. http://dx.doi.org/10.2172/893008.

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Chiba, Z., P. R. Lewis e L. C. Murguia. Mediated electrochemical oxidation treatment for Rocky Flats combustible low-level mixed waste. Final report, FY 1993 and 1994. Office of Scientific and Technical Information (OSTI), settembre 1994. http://dx.doi.org/10.2172/217838.

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Balazs, B., Z. Chiba, P. Hsu, P. Lewis, L. Murguia e M. Adamson. Destruction of hazardous and mixed wastes using mediated electrochemical oxidation in a Ag(II)HNO3 bench scale system. Office of Scientific and Technical Information (OSTI), febbraio 1997. http://dx.doi.org/10.2172/611759.

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Chiba, Z., P. R. Lewis e R. W. Kahle. FY 1992 Annual report: Mediated electrochemical oxidation treatment for Rocky Flats combustible low-level mixed waste. Final report to Rocky Flats Plant. Office of Scientific and Technical Information (OSTI), marzo 1993. http://dx.doi.org/10.2172/10177744.

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Van Rijn, Jaap, Harold Schreier e Yossi Tal. Anaerobic ammonia oxidation as a novel approach for water treatment in marine and freshwater aquaculture recirculating systems. United States Department of Agriculture, dicembre 2006. http://dx.doi.org/10.32747/2006.7696511.bard.

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Ammonia waste removal in recirculating aquaculture systems is typically accomplished via the action of nitrifying bacteria in specially designed biofilters that oxidize ammonia to produce nitrate. In the majority of these systems nitrate is discharged to the environment through frequent water exchanges. As environmental considerations have made it necessary to eliminate nitrate release, new strategies for nitrate consumption are being developed. In the funding period we showed that ammonia removal from wastewater could take place by an anaerobic ammonia oxidation process carried out by bacterial Planctomycetessp. Referred to as “anammox”, this process occurs in the absence of an organic source and in the presence of nitrite (or nitrate) as an electron acceptor as follows: NH₃ + HNO₂ -> N₂ + 2H₂O. Annamox has been estimated to result in savings of up to 90% of the costs associated with was wastewater treatment plants. Our objective was to study the applicability of the anammox process in a variety of recirculating aquaculture systems to determine optimal conditions necessary for efficient ammonia waste removal. Both seawater and freshwater systems operated with either conventional aerobic treatment of ammonia to nitrate (USA) or, in addition, denitrifying biofilters as well as anaerobic digestion of sludge (Israel) were tested. Molecular tools were used to screen and monitor different treatment compartments for the presence of Planctomycetes. Optimal conditions for the enrichment of the anammox bacteria were tested using laboratory scale biofilters as well as a semi-commercial system. Enrichment studies resulted in the isolation of some unique heterotrophic bacteria capable of plasmid-mediated autotrophic growth in the presence of ammonia and nitrite. Our studies have not only demonstrated the presence and viability of Planctomycetes spp. in recirculating marine and freshwater systems biofilter units but also demonstrated the applicability of the anammox process in these systems. Using our results we have developed treatment schemes that have allowed for optimizing the anammox process and applying it to recirculating systems.

Djordjevic, Katarina, Andjela Milojevic Samanovic, Mirjana Veselinovic, Vladimir Zivkovic, Victor Mikhaylovsky, Maria Mikerova, Vladimir Reshetnikov, Vladimir Jakovljevic e Tamara Nikolic Turnic. Oxidative stress mediated therapy in patients with rheumatoid arthritis: A systematic review and meta-analysis. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, settembre 2023. http://dx.doi.org/10.37766/inplasy2023.9.0064.

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Prusky, Dov, Noel Keen e John Browse. Modulation of the synthesis of the main preformed antifungal compound as abasis for the prevention of postharvest disease of C. gloeosporioides in avocado fruits. United States Department of Agriculture, dicembre 2001. http://dx.doi.org/10.32747/2001.7575273.bard.

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The most important pathological factor limiting fruit life after harvest in subtropical fruits are quiescent infections of anthracnose caused by Colletotrichum gloeosporioides. Prusky and Keen elucidated the mechanism of resistance in avocado fruits to quiescent infections of C. gloeosporioides and determined that the major biocide involved is the preformed compound,1-acetoxy-2-hydroxy-4-oxo-heneicosa-13, 15 diene. Two possibilities exist for maintaining fungitoxic levels of antifungal compounds in the tissue of ripening fruits: (i). Prevention of catabolism (ii). Induction of synthesis. Previous work has demonstrated that increased fruit susceptibility after fruit harvest occurs through diene catabolism mediated by oxidation of the antifungal compound by the enzyme lipoxygenase. Levels of a non-specific inhibitor, epicatechin, in turn, regulate activity of lipoxygenase, present in the peel of unripe but not ripe fruit. In this proposal, we examined the possibility of exploiting induced synthesis of the antifungal compound for the study of the synthetic pathway. The general objective of the present research was to study the mechanism of biosynthesis of natural antifungal compounds in order to regulate the process of resistance to postharvest diseases in ripening avocado fruits. The specific objectives of the research were: 1. To localize synthesis of the antifungal diene and modulate the process by biotic or a biotic elicitors. 2. To determine the relation between synthesis of the diene and accumulation in the peel and fruit resistance to decay 3. To characterize the biosynthetic pathway and the diene and the genes involved. The analysis of the antifungal compounds in avocado resulted in the detection of a new antifungal compound (E, Z, Z)-1-acetoxy-2-hydroxy-4-oxo- heneicosa-5, 12,15-triene. This new compound was shown to inhibit spore germination of C. gloeosporioides similarly as the antifungal diene. We had localized one of the biosynthetic places of these antifungal compounds in specialized idioblast cells (oil cells) in the mesocarp that can be easily enhanced by elicitors as ethylene. Results have also suggested that the antifungal compounds can be "exported" from the mesocarp to the pericarp where its main activity takes place. The search for the biosynthesis of antifungal compounds and the genes involved took two directions i. direct search for specific genes involved in the synthesis of the diene and ii. Indirect selection of genes using the differential display library. We have cloned , The most important pathological factor limiting fruit life after harvest in subtropical fruits are quiescent infections of anthracnose caused by Colletotrichum gloeosporioides. Prusky and Keen elucidated the mechanism of resistance in avocado fruits to quiescent infections of C. gloeosporioides and determined that the major biocide involved is the preformed compound,1-acetoxy-2-hydroxy-4-oxo-heneicosa-13, 15 diene. Two possibilities exist for maintaining fungitoxic levels of antifungal compounds in the tissue of ripening fruits: (i). Prevention of catabolism (ii). Induction of synthesis. Previous work has demonstrated that increased fruit susceptibility after fruit harvest occurs through diene catabolism mediated by oxidation of the antifungal compound by the enzyme lipoxygenase. Levels of a non-specific inhibitor, epicatechin, in turn, regulate activity of lipoxygenase, present in the peel of unripe but not ripe fruit. In this proposal, we examined the possibility of exploiting induced synthesis of the antifungal compound for the study of the synthetic pathway. The general objective of the present research was to study the mechanism of biosynthesis of natural antifungal compounds in order to regulate the process of resistance to postharvest diseases in ripening avocado fruits. The specific objectives of the research were: 1. To localize synthesis of the antifungal diene and modulate the process by biotic or a biotic elicitors. 2. To determine the relation between synthesis of the diene and accumulation in the peel and fruit resistance to decay 3. To characterize the biosynthetic pathway and the diene and the genes involved. The analysis of the antifungal compounds in avocado resulted in the detection of a new antifungal compound (E, Z, Z)-1-acetoxy-2-hydroxy-4-oxo- heneicosa-5, 12,15-triene. This new compound was shown to inhibit spore germination of C. gloeosporioides similarly as the antifungal diene. We had localized one of the biosynthetic places of these antifungal compounds in specialized idioblast cells (oil cells) in the mesocarp that can be easily enhanced by elicitors as ethylene. Results have also suggested that the antifungal compounds can be "exported" from the mesocarp to the pericarp where its main activity takes place. The search for the biosynthesis of antifungal compounds and the genes involved took two directions i. direct search for specific genes involved in the synthesis of the diene and ii. Indirect selection of genes using the differential display library. We have cloned D9 and D12 desaturase, a protein kinase and a elongase that their transcriptional activation is significantly enhanced during the enhanced synthesis of the antifungal diene. Although we are far away from a complete elucidation of the synthesis of the antifungal compound we have stepped forward determining some of the key steps that might be involved in its synthesis.

Zilinskas, Barbara A., Doron Holland, Yuval Eshdat e Gozal Ben-Hayyim. Production of Stress Tolerant Plants by Overproduction of Enzymatic Oxyradical Scavengers. United States Department of Agriculture, maggio 1993. http://dx.doi.org/10.32747/1993.7568751.bard.

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Most of the objectives that were outlined in the original proposal have been met with two exceptions. Briefly, our goals were to: (1) constract transgenic tobacco plants which overproduce one or more of the enzymatic oxyradical scavengers and associated ancillary enzymes, including superoxide dismutase, ascorbate peroxidase, glutathione peroxidase, glutathione reductase, and monodehydrascorbate reductase; (2) evaluate the tolerance of these transgenic plants to oxidative stress; and (3) extend these studies to an agronomically important crop such as citrus. As can be seen i the following pages, our objectives (1) and (2) have been achieved, although transgenic lines overexpressing phospholipid hydroperoxidase glutathione peroxidase (PHGPX) were not obtained and our evidence to date suggests that constitutive overexpressing of the enzyme is probably lethal. Howeever, transgenic tobacco expressing the antisense construct for PHGPX were obtained. Tobacco plants overexpressing ascorbate peroxidase and those sensesuppressing monodehydroascorbate reductase are more tolerant to oxidative stress, as mediated by the redox-cycling agent paraquant; in contrast, plants expressing the PHGPX-antisense construct are more sensitive to paraquat. Additional research is warranted on each of the six types of transgenic lines which we generated with regard to their tolerance to saline stress. Until recently, attempts to transform citrus were not very successful, and thus additional attention is currently being directed at objective (3). We are optimistic that use of the plant transformation vector, pBIN, will lead to stable transgenic citrus, as preliminary experiments demonstrate stable expression of the GUS reporter gene. Other important contributions resulting from this BARD project include the biochemical characterization of the first plant phospholipid glutathione peroxidase and the biochemical and molecular analysis of another key antioxidant enzyme, monodehydroascorbate reductase. Overall this BARD-supported project was quite successful, and the biological resource of numerous transgenic lines which have altered levels of antioxidant enzymes should be valuable for years to come.