Fig. 5.
A bubble (large circular object; a ≈ 80 μm) and a quartz particle (small, bright object near the center; ap ≈ 20 μm) form a streaming doublet with L ≈ 105 μm. A vesicle (arrows; R ≈ 10 μm) follows the streamlines of the doublet flow and is ruptured upon close encounter with the particle (Right). With these parameters, we infer the ratio of particle stokeslet and bubble stokeslet strengths to be s ≈ 0.15. This number, as well as the estimated standoff distance hp/a ≈ 0.75, was used for the simulation in Fig. 4. The images were taken at t = 0, 0.3, and 0.5 sec; taking into account the oscillatory character of the trajectory (Fig. 6), an average transport speed of ≈1 mm/sec results.