Incorporation Pathways

In general, chemicals can reach the body in three different ways  

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Traditionally, CVD reaction data have been reported in terms of growth rates and their dependence on temperature. The data are often confounded by mass-transfer effects and are not suitable for reactor analysis and design. Moreover, CVD reaction data provide little insight, if any, into impurity incorporation pathways. Therefore, the replacement of traditional macroscopic deposition studies with detailed mechanistic investigations of CVD reactions is an area of considerable interest. A recent, excellent review of CVD mechanistic studies, particularly of Si CVD, is available (98), and the present discussion will be limited to highlighting mechanisms of Si CVD and of GaAs deposition by MOVCD as characteristic examples of the combined gas-phase and surface reaction mechanisms underlying CVD. 

The lower molecular weight compounds are in general more abundant in the wet deposition than the heavier molecular weight compounds (Fig. 9). The former also occur predominantly in the atmospheric gas phase, while the latter are particle-bound in larger proportion [35]. The transfer of gas phase POP to rain and/or snowflakes is very effective [62-64], Wet deposition accounts for the predominant incorporation pathway of gas phase and particulate phase POPs. But the efficiency depends on the quantity of precipitation, which may show high variability between different sites and seasons. 

Correct and incorrect nucleotide incorporation pathways in DNA polymerase b. Biochem. Biophys. Res. Commun., 350, 521-529. 

For a description of acute intoxication by substances, the median lethal dose is usually used. This is the amount of substance at which the half of the exposed animals died in consequence of a single incorporation of the substance. Depending on the incorporation pathway, the following experimental durations for the determination of the acute toxicity are used ... 

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