Search results for "Oxidation."

Electrochemical Oxidation of Carboxylic Acids in Water at Boron-Doped Diamond (BDD) Anodes in the Range of Potential of Oxygen Evolution: Detection M…

2013

The electrochemical oxidation in water solutions of selected carboxylic acids (namely oxalic, formic, acetic, maleic, and succinic) at boron-doped diamond (BDD) anodes was investigated by polarization and chronoamperometric measurements. In the presence of low concentrations of carboxylic acids, current densities changed approximately linearly with the acid concentrations. Furthermore, when the current densities were plotted as a function of the chemical oxygen demand, a similar response was observed for all the investigated acids with the exception of oxalic acid. For high carboxylic acid concentrations, the linear variation is often loosen and different behaviors are observed depending on…

Antioxidant compound supplementation prevents oxidative damage in a Drosophila model of Parkinson's disease

2013

Loss-of-function mutations in the DJ-1 gene are linked to rare autosomal recessive forms of parkinsonism. In Drosophila, two DJ-1 orthologs have been identified, DJ-1α and DJ-1β. Several studies have shown that DJ-1β mutant flies are viable and fertile but exhibit age-dependent locomotor defects, shortened life span, and enhanced sensitivity to toxins that induce oxidative stress response compared to control flies. We also demonstrated that long-term dietary supplementation with antioxidant compounds was effective at increasing life-span values of DJ-1β mutants. These results, together with high levels of oxidative stress markers detected in newly eclosed DJ-1β mutant flies compared to cont…

Beeinflussung des Leberzellmetabolismus, der Freisetzung von reaktiven Sauerstoffspezies sowie Apoptoseaktivierung durch hypotherme oxygenierte Leber…

2003

Two different methods of liver preservation were compared : simple cold storage (CS) and hypothermic oxygenated perfusion extracorporal (HOPE). After 10 h of preservation (4°C) with modified UW solution reperfusion was performed by isolated liver perfusion for 90 minutes. Reperfusion injury was estimated by release of cytosolic enzymes, formation of superoxide anions, determination of lipid peroxidation, glycolytic metabolites, bileflow and by PCR analysis. The results showed that after cold storage the formation of reactive oxygen species was significant higher as compared with perfused livers. Correspondingly expressions of mediators (TNFα, NF kappa B, MIP-2, SAPK) and apoptosis (Caspase …

Oxidative stress and mitochondrial failure in the pathogenesis of glaucoma neurodegeneration

2015

This review focuses on oxidative stress and mitochondrial failure for understanding mechanisms of optic nerve damage in primary open-angle glaucoma. The chapter shows scientific evidence for the role of mitochondrial disbalance and reactive oxygen species in glaucoma neurodegeneration. Mitochondria regulate important cellular functions including reactive oxygen species generation and apoptosis. Mitochondrial alterations result from a wide variety of damaging sources. Reactive oxygen species formed by the mitochondria can act as signaling molecules, inducing lipid peroxidation and/or excitotoxicity with the result of cell lesion and death. Antioxidants may help to counteract oxidative stress…

Reactive oxygen species involvement in apoptosis and mitochondrial damage in Caco-2 cells induced by enniatins A, A1, B and B1

2013

The cytotoxic effects, the generation of reactive oxygen species (ROS) and lipid peroxidation (LPO) as well as the cell cycle disruption, the induction of apoptosis and changes in mitochondrial membrane potential (ΔΨm) as a function of increasing time have been determined in human colorectal adenocarcinoma (Caco-2) cells after exposure to enniatins (ENs) A, A₁, B and B₁. IC₅₀ values obtained by the MTT and Neutral Red assay, after 24, 48 and 72 h of exposure ranged from 0.5±0.1 to >15 μM. A significant increase (p≤0.05) in ROS generation and LPO production, as determined by the fluorescent probe H2-DCFDA and TBARS method respectively, was observed for all mycotoxins tested at 3.0 μM concent…

The protective effects of melanoidins in adriamycin-induced oxidative stress in isolated rat hepatocytes

2004

The importance of the antioxidants contained in foods is well recognized both for preserving the foods themselves and for supplying essential antioxidants in vivo. Among these, the melanoidins formed during food processing and storage represent a significant part of our diet, with an average intake of several grams per day. Melanoidins exhibit antioxidant properties in vitro through their protective effect against reactive oxygen species. Here we investigated the protective effect of the model glucose–glycine melanoidins on oxidative stress induced by adriamycin in hepatocytes isolated from rats. The study was performed by examining cell toxicity (lactate dehydrogenase) release in the mediu…

Pharmacological modulation of redox signaling pathways in disease

2020

Unexpectedly ambivalent O-2 role in the autocatalytic photooxidation of 2-methoxybenzyl alcohol in water

2015

An unusual autocatalytic photooxidation of 2-methoxybenzyl alcohol has been observed under UV irradiation in aqueous medium. The homogeneous oxidation is catalyzed by the corresponding aldehyde that is also the main oxidation product. The trend of alcohol disappearance rate matches the typical shape of an autocatalytic process, where a crucial and ambivalent role is played by the presence of molecular oxygen. Low oxygen concentrations give rise to a zero-order reaction since the beginning of irradiation, while higher amounts of oxygen reduce the alcohol oxidation rate until the aldehyde reaches a concentration high enough to speed up the alcohol's conversion. Experiments performed by varyin…

Aqueous selective photocatalytic oxidation of salicyl alcohol by TiO2 catalysts: Influence of some physico-chemical features

2021

Abstract Partial photocatalytic oxidation of salicyl alcohol (2-hydroxybenzyl alcohol) to salicylaldehyde in water was investigated under environmental friendly conditions in the presence of home-prepared and commercial TiO2 (Merck and Aeroxide P25) samples under UVA irradiation. The photocatalysts were characterized by using BET, XRD, SEM and/or TEM techniques. The effects of crystallinity degree, pH (3–11) and presence of a hole trap (ethanol) on the photocatalytic activity and product selectivity were investigated. 4-Hydroxybenzyl alcohol was also used to study the influence of the position of the substituent group in the aromatic ring. High alcohols conversion and product selectivity va…

Nanostructured rutile TiO2 for selective photocatalytic oxidation of aromatic alcohols to aldehydes in water

2008

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