Figure 5.

Dilatational modulus of LysoPC as a function of frequency for bubbles of radius ~ 150 μm, corresponding to larger alveoli. As in Fig. 4, for > 0.1 mM LysoPC, (2ε − γ) < 0 (dotted red line) over normal breathing frequencies (yellow). The crossover frequency for the Laplace Instability is slightly lower for the larger bubbles (Compare to Fig. 4), but the main effect of the larger bubble is seen at low frequencies. At high frequencies, (2ε − γ) > 0 for all concentrations and curvatures. Solid red lines are fits to Eqn. 22.