Ozone exposures

With rubber base adhesives, it is necessary to prevent their properties from changing during service life. Oxidative changes induced by thermal, ozone exposure and UV light can dramatically affect service life of rubber base adhesives. More precisely, the rubber and the resin are quite susceptible to oxidative degradation. Environmental and physical factors exert detrimental effects on rubber base adhesive performance. These effects can be mitigated by the incorporation of low levels of stabilizers during the fabrication process of the adhesive. 

The length and amount of cracks is assessed according to the Bayer method [72,73]. The ISO standard ozone test conditions involve a test temperature of 40°C zE 1°C and an ozone level of 50 5 pphm, with a test duration of 72 h. Testing is done under static [72] and/or dynamic strain [73]. These are accelerated tests and should be used for the relative comparison of compounds, rather than for the prediction of long-term service life. The method is rather complicated and demands a long duration of ozone exposure. Therefore, in some cases the rate constants of the antiozonants reaction with ozone in solution are used instead to evaluate the efficiency of different antiozonants [74]. 

Exposure to cigarette smoke Exposure to ozone Exposure to ionizing radiation... 

Much of the pulmonary NEP activity is believed to reside in the epithelium, as has been demonstrated in the ferret (Borson et al., 1986), and thus it is likely that inhaled ozone would preferentially destroy luminal NEP before affecting any enzymes in the vasculature, which may degrade peptides delivered by the intravenous route. This may explain the route-dependency of BHR after ozone in guinea pigs. Further evidence that the oxidant effects of inhaled ozone are selective is provided by the findings that pressor responses to angiotensin I (which requires conversion by ACE to angiotensin II) were not altered by ozone exposure (Yeadon et eU., 1992). 

Hotchkiss, J.A., Harkema, J.R. and Henderson, R.F. (1991). Effect of cumulative ozone exposure on ozone-induced nasal epithelial hyperplasia and secretory cell metaplasia in rats. Exp. Lung Res. 15, 589-600. 

Yeadon, M., Eve, D. and Payne, A.N. (1993b). Ozone exposure in guinea-pigs induces bronchial hyperreactivity to histamine and salbutamol, but not to leukotriene D4. Br. J. Pharmacol. 108, 220P. 

It is important in defining any analysis scheme that the analysis elements be consistent in scope, scale, and detail with each other and with the purposes of the analysis. Thus details of cohort exposure in microenvironments can provide valuable information on populations at risk if, in fact, pollutant concentrations are functions of micro-environments. It appears that micro-environments are clearly important in carbon monoxide (CO) exposure analysis because automobile generated CO concentrations are highly correlated with automobile usage patterns. It is not clear that ozone exposures are so correlated. Ozone commonly exists in "clouds" that are large compared to any one micro-environment, but drift over an area large compared to their size in the course of their formation and decay. 

Lysosyme Serous cells, neutrophils, macrophages Gram positive bacteria Lyse gram positive bacteria via cleavage of peptidoglycan Decreased production after ozone exposure [121]... 

Park, J.W., et al., Complement activation is critical to airway hyperresponsiveness after acute ozone exposure, Am. J. Respir. Crit. Care Med. 169, 6, 726, 2004. 

Dziedzic, D. and White, H.J., Response of T-cell-deficient mice to ozone exposure, J. Toxicol. Environ. Health. 21, 1-2, 57, 1987. 

OSHA ozone exposure limits, 17 815 OSHA Permissible Exposure Level (PEL), for sulfuric acid, 23 795 OSHA regulations, for vinyl chloride, 25 650, 651... 

United States, See also American entries Army Corps of Engineers Atomic Energy Commission (AEC) Environmental Protection Agency (EPA) Federal entries Food and Drug Administration (FDA) Government entries National entries OSHA ozone exposure limits U.S. entries acrylic fiber consumption in, ll 220t acrylic fiber production in, 11 189 advanced materials research, 1 696 air separation industry in, 17 754 aliphatic fluorocarbon production in,... 

There is some suggestive evidence that exposure to ozone accelerates the aging process(es). Bjorksten and Bjorksten and Andrews have presented evidence that aging is due to irreversible cross-linking between macromolecules, principally proteins and nucleic acids. Aldehydes were included in the list of cross-linking agents, and these can be produced in the lung as a result of ozone exposure. ... 

The lung is relatively rich in histamine-containing mast cells, so it is not surprising that a number of investigators have assessed the role of histamine in the pulmonary toxicity observed after ozone exposure. 

Potentiation of the action of acetylcholine, another bronchoconstrictive agent implicated as a mediator in asthma, has also been reported in guinea pigs exposed to ozone at at least 2 ppm for 30 min before inhalation of acetylcholine the effect was observed intermittently for up to 23 h after ozone exposure. 

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