Publications associées à Antioxidant Assay Based on Quenching of Photocatalytically Generated Reactive Oxygen Species

The Mn(VII)-H2O2 oxidation process: Abatement of electron-deficient N-containing organic compounds

Chemical oxidants applied in water treatment are electrophiles, which preferentially attack sites with higher electron density. This typically results in less efficient oxidative abatement of organic compounds with electronwithdrawing substituents. In this ...

Elsevier Science Sa2024

Oxidative Water Treatment: The Track Ahead

Urs von Gunten, Yun Ho Lee

Chemical oxidation has been applied in municipal water treatment for more than a century, initially for disinfection. In the early decades, chlorine disinfection was adopted in the fight against waterborne disease. However, the oxidative properties of chlo ...

2023

Detecting the metabolism of individual yeast mutant strain cells when aged, stressed or treated with antioxidants with diamond magnetometry

Mayeul Sylvain Chipaux

Free radicals play a key role in the ageing process. However, free radicals are small, reactive and short lived and thus challenging to measure. We utilize a new technique called diamond magnetometry for this pur-pose. We make use of nitrogen vacancy cente ...

ELSEVIER SCI LTD2023

Photochemical oxidation of phenols and anilines mediated by phenoxyl radicals in aqueous solution

Silvio Canonica, Urs von Gunten, Stephanie Christa Remke

Reactive intermediates formed upon irradiation of chromophoric dissolved organic matter (CDOM) contribute to the degradation of various organic contaminants in surface waters. Besides well-studied "short-lived" photo oxidants, such as triplet state CDOM (3 ...

PERGAMON-ELSEVIER SCIENCE LTD2022

Intrinsically High Capacity of Animal Cells From a Symbiotic Cnidarian to Deal With Pro-Oxidative Conditions

Gaëlle Delphine Toullec

The cnidarian-dinoflagellate symbiosis is a mutualistic intracellular association based on the photosynthetic activity of the endosymbiont. This relationship involves significant constraints and requires co-evolution processes, such as an extensive capacit ...

FRONTIERS MEDIA SA2022

Phototransformation of Organic Contaminants in Aquatic Systems: Characterization of Long-Lived Photooxidants Derived from Dissolved Organic Matter

Stephanie Christa Remke

The increasing interest in the fate of organic contaminants in the aquatic environment requires the elucidation of relevant abiotic transformation processes. These processes often involve the ubiquitous dissolved organic matter (DOM), a complex mixture of ...

EPFL2021

Image- and Fluorescence-Based Test Shows Oxidant-Dependent Damages in Red Blood Cells and Enables Screening of Potential Protective Molecules

Gerardo Turcatti, Michel Prudent, Benjamin Rappaz, Manon Sandra Bardyn, David Crettaz

An increase of oxygen saturation within blood bags and metabolic dysregulation occur during storage of red blood cells (RBCs). It leads to the gradual exhaustion of RBC antioxidant protective system and, consequently, to a deleterious state of oxidative st ...

2021

Impact of the Natural Compound Urolithin A on Health, Disease, and Aging

Johan Auwerx, Pénélope Andreux, Pamela Solange Valdés Undurraga, Davide D'Amico, Anurag Singh

Urolithin A (UA) is a natural compound produced by gut bacteria from ingested ellagitannins (ETs) and ellagic acid (EA), complex polyphenols abundant in foods such as pomegranate, berries, and nuts. UA was discovered 40 years ago, but only recently has its ...

2021

Coupled As and Mn Redox Transformations in an Fe(0) Electrocoagulation System: Competition for Reactive Oxidants and Sorption Sites

Sachiko Hirosue, Jasquelin Peña, Nathalie Manetti, Victor Carle Adrien Boureau

Iron electrocoagulation (EC) can be used for the decentralized treatment of arsenic(As)-contaminated groundwater. Iron EC involves the electrolytic dissolution of an Fe(0) electrode to Fe(II). This process produces reactive oxidants, which oxidize As(III) ...

AMER CHEMICAL SOC2020

Persulfate-Based Advanced Oxidation: Critical Assessment of Opportunities and Roadblocks

Urs von Gunten

Reports that promote persulfate-based advanced oxidation process (AOP) as a viable alternative to hydrogen peroxide-based processes have been rapidly accumulating in recent water treatment literature. Various strategies to activate peroxide bonds in persul ...

AMER CHEMICAL SOC2020

Generation of hydroxyl radical during chlorination of hydroxyphenols and natural organic matter extracts

Urs von Gunten, Eva Maria Rodriguez Franco

The generation of hydroxyl radicals ((OH)-O-center dot) during the chlorination of air saturated solutions of different hydroxyphenols (hydroquinone, resorcinol, catechol, gallic and tannic acids) at pH 7 has been determined by the formation of phenol (in ...

2020

Efficiency of pre-oxidation of natural organic matter for the mitigation of disinfection byproducts: Electron donating capacity and UV absorbance as surrogate parameters

Urs von Gunten

Pre-oxidation is often used before disinfection with chlorine to decrease the reactivity of the water matrix and mitigate the formation of regulated disinfection byproducts (DBPs). This study provides insights on the impact of oxidative pre-treatment with ...

PERGAMON-ELSEVIER SCIENCE LTD2020

Enhanced transformation of sulfonamide antibiotics by manganese(IV) oxide in the presence of model humic constituents

Urs von Gunten, Jun Ma, Yang Song, Jin Jiang, Yang Zhou

In this study, a manganese(IV) oxide-mediator (MnO2-mediator) system for the abatement of sulfonamide antibiotics was evaluated. Two simple model humic constituents, syringaldehyde (SA) and acetosyringone (AS), could promote the transformation of sulfonami ...

PERGAMON-ELSEVIER SCIENCE LTD2019

Two analytical approaches quantifying the electron donating capacities of dissolved organic matter to monitor its oxidation during chlorination and ozonation

Urs von Gunten

Electron-donating activated aromatic moieties, including phenols, in dissolved organic matter (DOM) partially control its reactivity with the chemical oxidants ozone and chlorine. This comparative study introduces two sensitive analytical systems to direct ...

2018

Ozone and chlorine reactions with dissolved organic matter - Assessment of oxidant-reactive moieties by optical measurements and the electron donating capacities

Urs von Gunten

Oxidation processes are impacted by the type, concentration and reactivity of the dissolved organic matter (DOM). In this study, the reactions between various types of DOM (Suwannee River fulvic acid (SRFA), Nordic Reservoir NOM (NNOM) and Pony Lake fulvic ...

2018

The antioxidant capacity of erythrocyte concentrates is increased during the first week of storage and correlated with the uric acid level

Hubert Girault, Michel Prudent, Niels Erik Lion, Fernando Cortes Salazar, Manon Sandra Bardyn, Sunny Isaïe Maye, Andreas Stephan Lesch

Background and Objectives: Red blood cells (RBCs) suffer from lesions during cold storage, depending in part on their ability to counterbalance oxidative stress by activating their antioxidant defence. The aim of this study was to monitor the antioxidant p ...

Wiley-Blackwell2017

Synchronic coupling of Cu2O(p)/CuO(n) semiconductors leading to Norfloxacin degradation under visible light: Kinetics, mechanism and film surface properties

Michaël Bensimon, Juan Kiwi, César Pulgarin, Sami Rtimi, Gcina Mamba

The study presents the first evidence for Norfoxacin photodegradation by uniform, adhesive and robust CuOx-polystyrene (CuOx-PES) films under visible light. Repetitive Norfloxacin degradation was attained on CuOx-PES films activated by visible light. The s ...

Elsevier2017

Non-invasive continuous monitoring of pro-oxidant effects of engineered nanoparticles on aquatic microorganisms

Paul Bowen, Christian Santschi, Olivier Martin, Volodymyr Koman, Nadia Rachel Von Moos

Engineered nanomaterials (ENMs) are key drivers for the development of highly sophisticated new technologies. As all new attainments, the rapidly increasing used of ENMs raise concerns about their safety for the environment and humans. There is growing evi ...

2017

Oxidative stability and microstructure of 5% fish-oil-enriched granola bars added natural antioxidants derived from brown alga Fucus vesiculosus

Louise Helene Soegaard Jensen

The aims of this study were to (i) investigate the ability of Icelandic brown algae Fucus vesiculosus extracts to inhibit lipid oxidation in granola bars fortified with fish oil-in-water emulsion; (ii) investigate whether addition of the seaweed extracts a ...

Wiley-Blackwell2017

Bactericide effects of transparent polyethylene photocatalytic films coated by oxides under visible light

Juan Kiwi, Sami Rtimi

This review addresses catalytic/photocatalytic films under visible light inducing fast bacterial inactivation. These films present uniform, stable and adhesive surfaces able to inactivate bacteria within minutes. Uniform sputtered polyethylene-TiO2 (PE-TiO ...

Elsevier2017