Development of a computational model for macroscopic predictions of device-induced thrombosis.

While cardiovascular device-induced thrombosis is associated with negative patient outcomes, the convoluted nature of the processes resulting in a thrombus makes the full thrombotic network too computationally expensive to simulate in the complex geometries and flow fields associated with devices. A macroscopic, continuum computational model is developed based on a simplified network, which includes terms for platelet activation (chemical and mechanical) and thrombus deposition and growth in regions of low wall shear stress (WSS). Laminar simulations are performed in a two-dimensional asymmetric sudden expansion geometry and compared with in vitro thrombus size data collected using whole bovine blood.

In vitro quantification of time dependent thrombus size using magnetic resonance imaging and computational simulations of thrombus surface shear stresses.

Thrombosis and thromboembolization remain large obstacles in the design of cardiovascular devices. In this study, the temporal behavior of thrombus size within a backward-facing step (BFS) model is investigated, as this geometry can mimic the flow separation which has been found to contribute to thrombosis in cardiac devices. Magnetic resonance imaging (MRI) is used to quantify thrombus size and collect topographic data of thrombi formed by circulating bovine blood through a BFS model for times ranging between 10 and 90 min at a constant upstream Reynolds number of 490.

Fate of Escherichia coli O157:H7 and Other Coliforms in Commercial Mayonnaise and Refrigerated Salad Dressing.

Commercial mayonnaise and refrigerated ranch salad dressing were inoculated at two levels with two strains of Escherichia coli O157:H7, a non-pathogenic E. coli , and the non-fecal coliform Enterobacter aerogenes . Results showed that at the high inoculation level (>10 colony forming units [CFU]/g) in mayonnaise stored at room temperature (ca.