Radiation oxidation

Alkylated aromatics have excellent low temperature fluidity and low pour points. The viscosity indexes are lower than most mineral oils. These materials are less volatile than comparably viscous mineral oils, and more stable to high temperatures, hydrolysis, and nuclear radiation. Oxidation stabihty depends strongly on the stmcture of the alkyl groups (10). However it is difficult to incorporate inhibitors and the lubrication properties of specific stmctures maybe poor. The alkylated aromatics also are compatible with mineral oils and systems designed for mineral oils (see Benzene Toulene Xylenes and ethylbenzene). ... 

PVAc, PVA and PVB homopolymers as well as the different copolymers mentioned above all have a similar chemical motif in common. They exhibit an all carbon-carbon single bond backbone, which needs to be broken at some point in a potential biodegradation mechanism. With respect to the backbone, poly(vinyl ester)s are closely related to poly(olefin)s, poly(styrene)s and poly(acrylate)s. These three are known not to be biodegradable. Instead, they usually decompose by the impact of UV radiation, oxidation and hydrolysis reactions, which are not considered to be biological degradation. 

It is possible for base mispairing in duplex DNA to be corrected by repair mechanisms because the information content is duplicated in the two complementary strands. For example, aberrant base pairing arising from environmental damage such as x-rays, ultraviolet radiation, oxidation, and chemical modification may be repaired as follows. 

USEPA, Ultrox International Ultaviolet Radiation/Oxidation Technology Applications Analysis Report, EPA/540/A5-89/012, Risk Reduction Engineering Laboratory, USEPA, Cincinnati, OH, 1990. 

Beltran et al. (1998) reported that the oxidation kinetics of nitroaromatic hydrocarbons at different pH levels (between 2 and 12) was similar to those found in 03/H202 oxidation — for example, the positive effect of pH on removal rate between pH 2 and 7 and partial inhibition at pH 12. The ozone efficiency increased with pH, from 30 to 40% (pH = 4) to 95% (pH 9 or 11). At pH 4, about a 10% difference was observed between the ozone efficiencies obtained during UV / ozone radiation oxidation and ozonation alone, while no difference was observed at pH 9 or 11. Figure 8.3 shows this effect for the degradation of vanillic acid, as reported by Benitez et al. (1997). 

Effect of hydrogen peroxide on ozone treatment system at ozone production rates of 10.5 and 15.7 lb/day. The x-axis shows the hydrogen peroxide-to-ozone mass ratio. The treatment efficiency report is the sum of oxidation and air stripping. (From USEPA, Ultrox International Ultraviolet Radiation/Oxidation Technology—Applications Analysis Report, EPA/540/A5-89/ 012, September 1990.)... 

Lesser, M. P, Acclimation of phytoplankton to UV-B radiation — oxidative stress and photoinhibition of photosynthesis are not prevented by UV-absorbing compounds in the dinoflagellate Prorocentrum micans, Mar. Ecol. Prog. Ser., 132, 287, 1996. 

The oxidation state of the complexed iron in these photoinitiators is 2 before and after exposure to actinic radiation. Oxidation of the complexed iron to the 3" state is possible after the irradiation step. Irradiation in the presence of an oxidant yields a stronger Lewis acid with increased reactivity for the epoxide polymerization. 

Free radicals are generated from within hepatocytes in several ways, such as ionizing radiation, oxidative metabolism by cytochrome P450, reduction and oxidation (redox) reactions that occur during normal metabolism, transition... 

A second DNA repair system in bacteria is designated excision repair. This repair system efficiently repairs DNA strands that have been irradiated with UV light or ionizing radiations, oxidatively damaged, or that have chemical-DNA adducts in... 

Administration (giving) sets Gamma-radiation Ethylene oxide Gamma-radiation Sterilization Gamma-radiation oxidative degradation when high vacuum autoclave used... 

Sutherland B.M., Bennet P.V., Sidorkina 0., Laval J., Clustered damage and total lesions induced in DNA by ionizing radiation oxidized bases and strand breaks. Biochemistry, 2000,39,8026-8031. 

Product stability and performance can be affected by exposure to several oxidative sources, including oxygen, free radicals, UV radiation, oxidative enzymes, catabolic oxidation, and chemical oxidation. Many antioxidants are also good UV absorbers due to their conjugated chemical structure. Typical antioxidants found in cosmetic products are flavonoids, polyphenols, carotenoids, thiols, tocopherol (vitamin E) and ascorbic acid (vitamin C) [71,72], According to Black [73], a combination of antioxidants from different classes is more effective than a single antioxidant due to an antioxidant cascade mechanism. 

SITE Program Demonstration of the Ultrox International Ultraviolet Radiation/Oxidation Technology... 

Similar compatibilization has been achieved through radiation, without any specific additives, involving recycled and virgin PET and radiation oxidized HDPE [10],... 

BURILLO G., HERRERA-FRANCO P. ET AL., Compatibilization of recycled and virgin PET with radiation-oxidized HDPE, Radiat. Phys. Chem., 63, 241 - 244, 2002. 

The similarity between the CB AO mechanism of phenols and HAS was reported at 25 °C in radiation oxidation of 2,4-dimethylpentane performed in the dark [207]. It was concluded that the respective NOH formed from 28, R = H during the stabilization process was the species responsible for the antioxidant effect (Scheme 27). The NOH is considered to be formed via trapping H by lltNO . The authors declared that i NOR are not involved in the stabilization of the radiation-oxidation of hydrocarbons and have doubts about the importance of the involvement of NOR in the regenerative cycle in an oxygen containing environment. 

Crosslinking - Reaction or formation of covalent bonds between chain-like polymer molecules or between polymer molecules and low-molecular compounds such as carbon black fillers. As a result of crosslinking, polymers such as thermosetting resins may become hard and infusible. Crosslinking is induced by heat, UV or electron-beam radiation, oxidation, etc. Crosslinking can be achieved either between polymer molecules alone as in unsaturated polyesters or with the help of multifunctional crosslinking agents such... 

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