Oxidation inhibited

Uses. Alkah metal and ammonium fluoroborates are used mainly for the high temperature fluxing action required by the metals processing industries (see Metal surface treatments Welding). The tendency toward BF dissociation at elevated temperatures inhibits oxidation in magnesium casting and aluminum alloy heat treatment. 

High temperature fatigue and fretting fatigue behavior has also been improved by implantation (113,114). This has been achieved by using species that inhibit oxidation or harden the surface. It is generally accepted that fretting behavior is closely coimected to oxidation resistance, perhaps due to third party effects of oxidation products. Oxidation resistance alone has also been improved by ion implantation (118—120). 

High Temperature Corrosion. The rate of oxidation of magnesium adoys increases with time and temperature. Additions of berydium, cerium [7440-45-17, lanthanum [7439-91-0] or yttrium as adoying elements reduce the oxidation rate at elevated temperatures. Sulfur dioxide, ammonium fluoroborate [13826-83-0] as wed as sulfur hexafluoride inhibit oxidation at elevated temperatures. 

Derivatives of ubiquiaones are antioxidants for foodstuffs and vitamins (qv) (217,218). Ubichromenol phosphates show antiinflammatory activity (219). Chroman o1 compounds inhibit oxidation of fats and can be used ia treatment of macrocytic anemias (220). Monosulfate salts of 2,3-dimethoxy-5-methyl-6-substitutedhydroquiaone have been reported to be inhibitors of Hpid oxidation ia rats (221). Polymers based on chloranilic and bromanilic acid have been prepared and contain oxygenated quiaones (63), which are derived from 1,2,3,4-benzenetetrol (222). 

Radical Scavengers Hydrogen-donating antioxidants (AH), such as hindered phenols and secondary aromatic amines, inhibit oxidation by competing with the organic substrate (RH) for peroxy radicals. This shortens the kinetic chain length of the propagation reactions. 

Low concentiations of alkylated paiaphenylenediamines such as -di-ti t-butyl-j )-phenylenediamine [69796 7-OJ are added to gasoline to inhibit oxidation (see Amines, AROMATic-PHENYLENEDiAMiNEs). 

Procedure. Prepare the dithiol reagent by adding 0.1 -0.2 g of dithiol to 100 mL of 0.25M sodium hydroxide solution, followed by 0.5 mL of thioglycollic acid (to inhibit oxidation of the reagent) keep at 5 °C and prepare fresh daily. 

Atractyloside inhibits oxidative phosphorylation by inhibiting the transporter of ADP into and ATP out of the mitochondrion (Figure 12-10). 

JACOBSEN C, HARTVIGSEN K, THOMSEN M K, HANSEN L F, LUND P, SKIBSTED L H, H0LMER G, ADLER-NissEN J and MEYER A s (2001) Lipid oxidation in fish oil enriched mayonnaise calcimn disodium ethylenediaminetetraacetate, but not gallic acid, strongly inhibited oxidative deterioration, J Agric Food Chem, 49, 1009-19. 

RAMANATHAN L and DAS N p (1993) Natural products inhibit oxidative rancidity in salted cooked ground fish, J Food Sci, 58, (2), 318-20. 

Parthasarathy, S., Young, S.G., Witztum, J.L., Pittman, R.C. and Steinberg, D. (1986). Probucol inhibits oxidative modification of low density lipoprotein. J. Clin. Invest. 7, 641-644. 

Benzodiazepines (alprazolam) COCs may inhibit oxidative metabolism Increase side effects of benzodiazepines... 

As mentioned previously, the ability of carotenoids to inhibit oxidative stress was tested in vitro in many different cell types. In the retina only lutein and zeaxanthin accumulate in sufficient concentrations to exert direct antioxidant effects, therefore our further discussion of these antioxidant effects will be focused mainly on those two xanthophylls. 

Very interesting behavior of incorporating anions can be observed when a multicomponent electrolyte is used for oxide formation. Here, anion antagonism or synergism can be observed, depending on the types of anions used. The antagonism of hydroxyl ions and acid anions has been observed in a number of cases. Konno et a/.181 have observed, in experiments on anodic alumina deterioration and hydration, that small amounts of phosphates and chromates inhibit oxide hydration by forming monolayer or two-layer films of adsorbed anions at the oxide surface. Abd-Rabbo et al.162 have observed preferential incorporation of phosphate anions from a mixture of phosphates and chromates. 

Following the Bolland-Gee Scheme 2 for non-inhibited oxidation occurring under stationary conditions, the following equation is frequently valid. 

Niclosamide inhibits oxidative phosphorylation and stimulates adenosine tripho-sphatese activity in the mitochondria of cestodes, killing the scolex and proximal segments of the tapeworm both in vitro and in vivo. The scolex of the tapeworm, then loosened from the gut wall, may be digested in the intestine and thus may not be identified in the stool even after extensive purging [90,91], Niclosamide is not appreciably absorbed from the gastrointestinal tract [92,93] and the side effects have primarily been limited to gastrointestinal symptoms. 

This method is also used to measure ex vivo low-density lipoprotein (LDL) oxidation. LDL is isolated fresh from blood samples, oxidation is initiated by Cu(II) or AAPH, and peroxidation of the lipid components is followed at 234 nm for conjugated dienes (Prior and others 2005). In this specific case the procedure can be used to assess the interaction of certain antioxidant compounds, such as vitamin E, carotenoids, and retinyl stearate, exerting a protective effect on LDL (Esterbauer and others 1989). Hence, Viana and others (1996) studied the in vitro antioxidative effects of an extract rich in flavonoids. Similarly, Pearson and others (1999) assessed the ability of compounds in apple juices and extracts from fresh apple to protect LDL. Wang and Goodman (1999) examined the antioxidant properties of 26 common dietary phenolic agents in an ex vivo LDL oxidation model. Salleh and others (2002) screened 12 edible plant extracts rich in polyphenols for their potential to inhibit oxidation of LDL in vitro. Gongalves and others (2004) observed that phenolic extracts from cherry inhibited LDL oxidation in vitro in a dose-dependent manner. Yildirin and others (2007) demonstrated that grapes inhibited oxidation of human LDL at a level comparable to wine. Coinu and others (2007) studied the antioxidant properties of extracts obtained from artichoke leaves and outer bracts measured on human oxidized LDL. Milde and others (2007) showed that many phenolics, as well as carotenoids, enhance resistance to LDL oxidation. 

Like the oxidation of hydrocarbons, the autocatalytic oxidation of polymers is induced by radicals produced by the decomposition of the hydroperoxyl groups. The rate constants of POOH decomposition can be determined from the induction period of polymer-inhibited oxidation, as well as from the kinetics of polymer autoxidation and oxygen uptake. The initial period of polymer oxidation obeys the parabolic equation [12]... 

Depending on the oxidation conditions and its reactivity, the inhibitor InH and the formed radical In can participate in various reactions determining particular mechanisms of inhibited oxidation. Of the various mechanisms, one can distinguish 13 basic mechanisms, each of which is characterized by a minimal set of elementary steps and kinetic parameters [38,43 15], These mechanisms are described for the case of initiated chain oxidation when the initiation rate v = const, autoinitiation rate fc3[ROOH] -C vy and the concentration of dissolved dioxygen is sufficiently high for the efficient conversion of alkyl radicals into peroxyl radicals. The initiated oxidation of organic compounds includes the following steps (see Chapter 2). 

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