Additives anti-oxidants

It should be noted that DNP use causes an increase in free radical production. Those who used DNP supplemented their diet with additional anti-oxidants such as vitamins C E, glutamine, and glutathione. 

Most explosives which are used by the military are solids under normal conditions and are usually obtained as granules on a technical scale. These granules are then mixed with other explosives and energetic (e.g. binder, plastiziser) or non-energetic additives (anti-oxidants, wetters, wax) and made into their final form using one of the following technical processes ... 

The redox state of a cell is mediated by the ratios of reduced and oxidized pyridine nucleotides (NADH/NAD/NADPH/NADP) and thiols such as reduced and oxidized GSH (GSH/GSSG) and thioredoxin/thior-edoxin disulphide. In addition, anti-oxidants such as vitamin E (tocopherol) and ascorbate (vitamin C) can reduce ROS non-enzymatically. 

Examine fuel additives (anti-oxidants, detergents, impurities)... 

The various additives used to obtain the required properties include anti-knock compounds, anti-oxidants, metal deactivalors, anti-icing additives, etc. 

The base lubricant is usually a petroleum oil while the thickener usually consists of a soap or soap mixture. In addition they may contain small amounts of free alkali, free fatty acid, glycerine, anti-oxidant, extreme-pressure agent, graphite or molybdenum disulphide. 

Anti-oxidants are the most extensively used additives and will be found in oils and greases which are expected to operate for considerable periods or under conditions that would promote oxidation. Typical examples are crankcase oils and bearing greases. 

The products of oil oxidation will attack metals, and this can be prevented by keeping the system free from pro-oxidative impurities and by the use of anti-oxidants. These additives will not, however, prevent rusting of ferrous surfaces when air and water are present in the mineral oil. The presence of absorbed air and moisture is inevitable in lubricating systems and therefore the oil must be inhibited against rusting. These additives, which are homogeneously mixed with the oil, have an affinity for metal, and a strongly absorbed oil film is formed on the metal surface, which prevents the access of air and moisture. 

These problems of engine lubrication can be overcome by using highly refined oil. The resistance to oxidation is further enhanced by the use of anti-oxidants. The addition of corrosion-inhibitors counters acidic materials produced by combustion at low engine temperatures. 

Mineral oil alone, no matter how high its quality, cannot adequately carry out all the duties outlined above and hence the majority of hydraulic oils have their natural properties enhanced by the incorporation of four different types of additives. These are an anti-oxidant, an anti-wear... 

Experience indicates that careful selection of base oils and anti-oxidation additives considerably reduce such deposits. Nevertheless, the use of top-class oil is no guarantee against trouble if maintenance is neglected. For complete safety, both the oil and the compressor system must enjoy high standards of care. 

The autoxidation of aldehydes, and of other organic compounds, may be lessened considerably by very careful purification—removal of existing peroxides, trace metal ions, etc.—but much more readily and effectively by the addition of suitable radical inhibitors, referred to in this context as anti-oxidants. The best of these are phenols and aromatic amines which have a readily abstractable H atom, the resultant radical is of relatively low reactivity, being able to act as a good chain terminator (by reaction with another radical) but only as a poor initiator (by reaction with a new substrate molecule). 

Polymers containing no secondary or tertiary C-H or are aromatic (PEEK or Kevlar ) or perfluorpolymers (PTFE) are generally resistant to oxidation and require no anti-oxidant additives. However, the high temperature necessary for curing or fabrication of high performance polymers (especially for aerospace applications) can cause oxidation. For this reason, these materials are often prepared and fabricated under a nitrogen atmosphere. 

Zinc dithiophosphates act as anti-oxidants by promoting the decomposition of hydroperoxides. The mechanism of this reaction is complicated involving hydroperoxides and peroxy radicals192,193 and is also affected by the other additives present in the lubricant oil.194 However the first step is thought to be a rapid initial reaction of the zinc dithiophosphate and hydroperoxide to give a basic compound [Zn4(/i4-0)(S2P(0R)2)6] (Equation 88 Figure 9).141... 

Bao H, Ren H, Endo H, Takagi Y and Hayashi T. 2004. Effects of heating and the addition of seasonings on the anti-mutagenic and anti-oxidative activities of polyphenols. Food Chem 86(4) 517—524. 

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