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We analyzed the dynamics of an influenza A/Albany/1/98 (H3N2) viral infection, using a set of mathematical models highlighting the differences between in vivo and in vitro infection. For example, we found that including virion loss due to cell entry was critical for the in vitro model but not for the in vivo model. Experiments were performed on influenza virus-infected MDCK cells in vitro inside a hollow-fiber (HF) system, which was used to continuously deliver the drug amantadine. The HF system captures the dynamics of an influenza infection, and is a controlled environment for producing experimental data which lend themselves well to mathematical modeling. The parameter estimates obtained from fitting our mathematical models to the HF experimental data are consistent with those obtained earlier for a primary infection in a human model. We found that influenza A/Albany/1/98 (H3N2) virions under normal experimental conditions at 37°C rapidly lose infectivity with a half-life of ~ 6.6 ± 0.2 h, and that the lifespan of productively infected MDCK cells is ~ 13 h. Finally, using our models we estimated that the maximum efficacy of amantadine in blocking viral infection is ~ 74%, and showed that this low maximum efficacy is likely due to the rapid development of drug resistance.

An oxygen chemisorption method has been developed for measuring the active surface area of supported and unsupported VzOs following reduction in hydrogen. It is shown that to achieve complete reduction of the vanadia surface without reducing the bulk, reduction must be carried out at 640 K. Oxygen uptakes of unsupported samples reduced at close to this temperature yield an oxygen atom site density of 3.2 X 10l8 a value near that expected for a monolayer. The same oxygen chemisorption technique is applied to silica-supported V205. Laser Raman spectroscopy confirms that, near 640 K, oxygen chemisorbs primarily at the surface of the dispersed vanadia but does not exchange with the bulk of the oxide. For very low weight loadings, a limiting stoichiometry of one adsorbed oxygen atom per vanadium atom is obtained. This stoichiometry is used to calculate dispersions ranging from 93% to 50% for supported VzOs samples of 0.3-9.8% weight loading.

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