Effect of the lack of PS in platelets on clot contraction. (A) Representative images of clot contraction at different points after induction with thrombin 10 U/mL in Pros1^lox/loxPf4Cre⁻ and Pros1^lox/loxPf4Cre⁺ PRP (n = 3/genotype). (B) Representative SEM images of the contracted clot at the external surface at different magnifications: scale bar, 10, 2, and 1 µm for ×3200, ×10 000, and ×30 000, respectively). (C) Representative SEM images of the contracted clot in the middle of the clot at different magnifications: scale bar, 2 and 1 µm for ×10 000 and ×30 000, respectively; scale bar, 500 nm for ×50 000. (D) Quantification of fibrin network density in Pros1^lox/loxPf4Cre⁻ and Pros1^lox/loxPf4Cre⁺ mice. Measurements are presented as mean ± SEM. **P ≤ .01.