12 results for “Reaction Department”
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Medical study · Medical research · 2019
Iron from a geochemical viewpoint. Understanding toxicity/pathogenicity mechanisms in iron-bearing minerals with a special attention to mineral fibers
…and the experimental methods used for their study. Special attention is devoted to the Fenton-like chain reaction involving Fe2+ in the formation of highly reactive hydroxyl radicals. The final part of this review deals with…
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Medical study · Medical research · 2010
New detoxification processes for asbestos fibers in the environment
…Val Malenco fibers into non-fibrous debris. Chrysotile's crystal and spectral signatures disappeared, and magnesium oxalate was the only crystalline reaction product detected, apart from reactor steel debris. Treated Balangero fibers still showed serpentine features…
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Medical study · Medical research · 2001
Spontaneous polymerisation on amphibole asbestos: relevance to asbestos removal
…solution of eugenol, a substance that can form a lignin-like polymer (a solid resembling a natural component of wood). After the reaction, the fibres appeared to be completely included in the polymer. In electron microscope…
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Medical study · Medical research · 2003
Ascorbic acid modifies the surface of asbestos: possible implications in the molecular mechanisms of toxicity
…consequence of the erosion of the outmost layers while hydration of silica tetrahedra yields new silanol groups. The activity in the Fenton-like reaction (OH from H(2)O(2)) decreases following surface iron depauperation. Conversely…
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Medical study · Medical research · 2001
Free radical generation in the toxicity of inhaled mineral particles: the role of iron speciation at the surface of asbestos and silica
…1.3 to 29 nmol/mg. It also increased one radical reaction, breaking a carbon-hydrogen bond, about 3-fold, while heating in air fully stopped that reaction. The other reaction, hydroxyl radical release from hydrogen…
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Medical study · Medical research · 1995
Role of iron in the reactivity of mineral fibers
…chemical processes that implicate surface iron as a primary cause of toxicity are: free radical release, mobilization by chelators, iron-catalyzed reactions. Three kinds of solids are compared: (i) well-known toxic materials, for example asbestos…
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Medical study · Medical research · 2005
Potential toxicity of nonregulated asbestiform minerals: balangeroite from the western Alps. Part 3: Depletion of antioxidant defenses
…crocidolite incubation. This effect was not related to any increased content of oxidized glutathione, or to any enhanced efflux of glutathione, suggesting that balangeroite fibers, like crocidolite, might favor the reaction of GSH with other molecules.
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Medical study · Medical research · 2017
Assessment of the potential respiratory hazard of volcanic ash from future Icelandic eruptions: a study of archived basaltic to rhyolitic ash samples
…worldwide. All samples generated a low level of hydroxyl radicals (HO•), a measure of surface reactivity, through the iron-catalyzed Fenton reaction compared to concurrently analyzed comparative samples. However, radical generation increased after 'refreshing' sample surfaces…
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Medical study · Medical research · 1995
Free radical generation at the solid/liquid interface in iron containing minerals
…asbestos whereas the two oxides are mostly inert. Conversely magnetite turns out to be an excellent catalyst for hydrogen peroxide disproportionation while haematite is inactive also in this reaction. The results agree with the implication of…
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Medical study · Medical research · 2000
In vitro cleavage by asbestos fibers of the fifth component of human complement through free-radical generation and kallikrein activation
…role in inflammatory reactions characteristic of asbestosis through mechanisms involving iron ions, hydroxyl radicals, and oxidized C5-ike fragments. The ferrous ions present at the asbestos fiber surface trigger this activation and catalyze, via Fenton reaction…
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Medical study · Medical research · 2012
Surface reactivity and cell responses to chrysotile asbestos nanofibers
…Alps. Electron microscopy, X-ray diffraction, and fluorescence spectroscopy revealed that the procedure does not affect mineralogical and chemical composition. Surface reactions related to oxidative stress, free radical generation, bioavailability of iron, and antioxidant depletion, revealed…
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Medical study · Medical research · 2003
Long and short fiber amosite asbestos alters at a different extent the redox metabolism in human lung epithelial cells
…cells A549, long amosite fibers, more effectively than the short ones, initiate free radical reactions, inhibit the glucose 6-phosphate dehydrogenase activity and the pentose phosphate pathway, decrease the intracellular level of reduced glutathione, and increase…