To cite this article: Onasoga-Jarvis AA, Puls TJ, O'Brien SK, Kuang L, Liang HJ, Neeves KB. Thrombin generation and fibrin formation under flow on biomimetic tissue factor-rich surfaces. J Thromb Haemost 2014; 12: 373-82.Summary. Background: Blood flow regulates coagulation and fibrin assembly by controlling the rate of transport of zymogens, enzymes and plasma proteins to and from the site of an injury. Objective: The objective of this work was to define the hemodynamic conditions under which fibrin can form under flow on tissue factor (TF)-rich substrates. Methods: TF-coated silica beads (~800 nm) were patterned into 18-85-lm spots. Normal pooled plasma and factors VIII, IX and XI deficient plasmas were perfused over the beads coated with 0.08, 0.8 and 8 molecules-TF lm À2 at shear rates of 50-1000 s À1 . Fibrin deposition and thrombin generation were measured by fluorescence microscopy in a hydrodynamic focusing microfluidic device. Results and Conclusions: Fibrin deposition was supported on patterned bead spots, but not planar TF substrates at the same surface TF concentration. There was a threshold spot size and a shear rate dependent TF concentration that was necessary to support fibrin polymerization. FVIII and FIX had minor effects on fibrin dynamics at 8 molecules-TF lm À2, but were essential at 0.8 molecules-TF lm À2 . The absence of FXI influenced thrombin generation and fibrin deposition at both 0.8 and 8 molecules-TF lm À2 . These results show that fibrin deposition requires perturbations in the flow field that protect reactions from dilution by flow under venous and arterial conditions. FVIII and FIX have a modest effect on fibrin deposition at high TF concentrations, but are necessary for fibrin deposition at low TF concentrations. FXI amplifies thrombin generation under flow at both low and high TF concentrations.

Time-lapse, multicomponent seismic data acquired during the CO2 flood at Delhi Field, Louisiana are used to identify zones containing high residual bulk oil volume and to target the location of new injection wells in the field. The data are used to monitor the reservoir and to see if the predicted zones of high residual oil are contacted by the enhanced oil recovery (EOR) process. Because the reservoir is shallow and injection pressures are relatively high, the cap rock is monitored. Stresses associated with injection induce observable shear-wave splitting anomalies in the cap rock. Stresses transmitted into the shale-confining layer by the injection process are not believed indicative of rupturing and CO2 leakage. The ability to monitor geomechanical changes through shear-wave splitting is an important new use of multicomponent seismic data.