Free-in-flow VWF extension in shear flow. (A) Histogram of VWF length at 6 shear stresses (20, 50, 80, 100, 150, and 200 dyn/cm2). (B) Mean extension vs shear stress (ο) and standard deviation vs shear stress (Δ) of VWF molecules for histograms shown in panel A. Monotonic increases in mean and standard deviation are both consistent with molecules extending under flow. (C) Percentiles 50 to 90 of VWF length vs shear stress for histograms in panel A. (D) Nonparametric statistical significance testing using Mann-Whitney U test comparing each shear stress length distribution. Values for P < .05 indicate statistical significance. (E) Three example trajectories of VWF at 150 dyn/cm2 with different PULSIS-corrected lengths. Example molecules of a long, middle, and short extended molecule. (F) Corresponding plots of pulse length vs relative pulse duration for trajectories in panel E. The y-intercept represents motion blur–corrected lengths for VWF molecules.
