Search results for "Oxydation"
showing 10 items of 32 documents
The combined action of 9 lipoxygenase and galactolipase is sufficient to bring about programmed cell death during tobacco hypersensitive response
2005
International audience; Oxylipins, derived from fatty acid hydroperoxides (FAHs), are thought to play different roles during plant pathogen interactions. During hypersensitive response (HR) some of them serve as signals necessary for defence gene activation whereas others could contribute to pathogen killing or could participate in the execution of plant programmed cell death (PCD) associated with this resistance. In order to address the role of these compounds in the latter process, we have closely observed lipid peroxidation, the first step of this metabolic pathway, under different situations which led either to accelerated or inhibited HR cell death. The oxidative process has been studi…
Oxidation-Induced Increase In Photoreactivity of Bovine Retinal Lipid Extract
2017
Open access original paper Source : 10th EPR Workshop on Applications of EPR in Biology and Medicine, 2016 in Krakow, POLAND.; International audience; The mammalian retina contains a high level of polyunsaturated fatty acids, including docosahexaenoic acid (22:6) (DHA), which are highly susceptible to oxidation. It has been shown that one of the products of DHA oxidation-carboxyethylpyrrole (CEP), generated in situ, causes modifications of retinal proteins and induces inflammation response in the outer retina. These contributing factors may play a role in the development of age-related macular degeneration (AMD). It is also possible that some of the lipid oxidation products are photoreactiv…
Molecular basis of the effects of argan oil on mitochondrial and peroxisomal metabolism of the fatty acids and inflammation
2012
The objective of this thesis work was to explore the molecular basis of Argan Oil (AO) effects on the mitochondrial and peroxisomal lipid metabolism and to elucidate its anti-inflammatory potential. We thus showed, initially, that the artisanal method preparation preserved the antioxidant properties of AO preventing the oxidation of the ferulic acid, by contrast to AO of commercial origin. Then, the treatment by the AO or lipopolysaccharides (LPS) of human fibroblasts, the cellular model of pseudo-neonatal adrenoleukodystrophy (P-NALD), revealed for the AO that peroxisomes proliferation is independent from the activation of the nuclear receptor PPARα and the co-activator PGC-1α. On the othe…
Halogenated (arylsulfanyl)pyridines syntheses and their derivatives by C-S and C-X couplings catalyzed by palladium complexes
2018
C–H activation of aryl compounds directed by 2-sulfonylpyridine and 2-sulfanylpyridine moiety for the formation of C–X (X = F, Cl, Br, I) bonds was studied. First, the syntheses of thioethers (2-(arylsulfanyl)pyridines) and sulfones (2-(arylsulfonyl)pyridines) were necessary for the progress of this project. A C–S coupling catalyzed by palladium complexe between thioaryls and halogenated heterocycles was performed for the synthesis of thioethers. The cheap ligand bis(diphenylphosphino)ferrocene (dppf) was used for this convenient reaction. Then, oxidation of thioethers was performed to synthesize sulfones. Halogenation of these compounds was studied with ortho-directed C–H activation cataly…
Behaviour of the high temperature corrosion of metals (TiAl3) coated with titanium aluminide
2010
During this study, intermetallic coatings TiAlx (x=1,2,3) were performed on titanium substrates: pure titanium and the commercial alloy, TA6V. The aim of this study was to elaborate aluminiure coatings on the surface and characterize the behaviour of these coated materials in oxidation at high temperature under air laboratory, under air enriched with water vapour and with sulfur. The coated materials were tested at three temperatures: 700°C, 800°C and 900°C. The coatings were realized at 1000°C by the pack-cementation process. The coatings realized are always adherent to the substrate. During oxidation the retrodiffusion of aluminium changes the nature of the phases and the organisation of …
Conservation and functional preservation of agri-food interest yeasts
2018
The use of yeasts in industry is inseparable from their ability to be produced and dehydrated. This dehydration process causes various dysfunctions in yeast cells that affect their functionality and viability. In order to protect yeasts from dehydration, food additives are often used as emulsifiers and antioxidants. However, yeasts are able to produce naturally protective substances, such as glutathione (GSH) and trehalose (TRE). In this context, three non-Saccharomyces (NS) strains, belonging to the different genera and species Torulaspora delbrueckii, Metschnikowia pulcherrima and Lachancea thermotolerans, were studied in this thesis. Despite the great interest aroused by their multiple a…
Effects of modulation of body fat in production of adiponectin in mice : consequences on hepatic metabolism of lipids
2010
Adiponectin (ApN), a 30-kDa adipokine abundantly produced by adipose tissue has been described for the first time in 1995. Early findings demonstrating serum adiponectin levels are inversely correlated with obesity initiated intense investigation of the relationship between adiponectin and all symptoms of the metabolic syndrome. Of these studies, strong evidence suggests that a weight loss induced by medication or hypocaloric diet led to increased circulating ApN levels and improvement of biochemical parameters. Thus, high levels of ApN have been correlated with an improvement of insulin sensitivity and lipid parameters reducing cardiovascular risk. However mechanisms involved in the improv…
Multifunctional biosourced materials : durability of unidirectional recycled matrix composites reinforced with flax fibers
2022
Now more than ever, many engineering sectors are turning to natural fiber composites because of the need for more environmentally friendly solutions. One of the main challenges in developing the use of biocomposites in outdoor applications is the lack of knowledge about their long-term durability. The main objective of this work is to provide a better understanding of the mechanisms involved in photooxidative aging of unidirectional composites made of a virgin or recycled polypropylene matrix, reinforced with long flax fibers. In addition, this work aims to study the potential use of a recycled matrix by comparing the evolution of its behavior to photooxidative aging with a virgin matrix. T…
Study of a chromia-forming alloy behavior as interconnect material for High Temperature Vapor Electrolysis
2011
In High Temperature Vapor Electrolysis (HTVE) system, the materials chosen for the interconnectors should have a good corrosion behaviour in air and in H2-H2O mixtures at 800°C, and keep a high electronic conductivity over long durations as well. In this context, the first goal of this study was to evaluate a commercial ferritic alloy (the K41X alloy) as interconnect for HTVE application. Oxidation tests in furnace and in microbalance have therefore been carried out in order to determine oxidation kinetics. Meanwhile, the Area Specific Resistance (ASR) was evaluated by Contact Resistance measurements performed at 800°C. The second objective was to improve our comprehension of chromia-formin…
Experimental characterization of micromechanical and microphological properties of nickel base alloys strained by the growth of an ovide payer made i…
2011
The loss of the corrosion resistance of the alloy 600, a nickel base alloy, during the oxidation in pressurized water reactor (PWR) has been demonstrated by many studies. It induces the intergranular stress corrosion cracking (IGSCC). If the chemical composition and the structure of the growing oxide are well-known, the mechanical influence of the oxide on the alloy has not been fully studied, yet. This study aims at bringing new knowledge of the oxidation impact on the mechanical response of the alloy. A new methodology is introduced for determining the local nanodeformation of the alloy 600 induced either by an oxidation or by a tensile loading. This method is based on nanodots disposed a…