Carbon dioxide distribution with depth

Ibrahim et al. 1963). Aiken and Braitman (1989) determined that cyanide has a direct effect on neurons not mediated by its inhibition of metabolism. Consistent with the view that cyanide toxicity is due to the inability of tissue to utilize oxygen is a report that in cyanide-intoxicated rats, arterial p02 levels rose, while carbon dioxide levels fell (Brierley et al. 1976). The authors suggested that the low levels of carbon dioxide may have led to vasoconstriction and reduction in brain blood flow therefore, brain damage may have been due to both histotoxic and anoxic effects. Partial remyelination after cessation of exposure has been reported, but it is apparent that this process, unlike that in the peripheral nervous system, is slow and incomplete (Hirano et al. 1968). The topographic selectivity of cyanide-induced encephalopathy may be related to the depth of acute intoxication and distribution of blood flow, which may result in selected regions of vascular insufficiency (Levine 1969). 

The oxidation of a VOC to carbon dioxide is conducted over a catalytic bed consisting of porous particles with a diameter of 4 mm. The catalyst particles contain Pt as the active component, which is distributed evenly within each particle. It is suggested to use the same particles but with the Pt placed at the external surface of each particle and at a depth up to 1/10 of its diameter so that the activity of the catalyst is increased. If the reaction is fust order with respect to the VOC, and on the grounds that the active surface of Pt remains the same in the two cases ... 

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