Concentration profiles of 1 and 2.5 μm beads during blood flow. Hematocrit effects

Freeze-capture techniques were used to obtain concentration profiles of 1.0 and 2.5 μm latex beads in suspension flows with hematocrits from 15 to 60%. Profiles with near-wall concentrations more than twice the central concentration occurred for 2.5 μm beads in this range of hematocrits, but the near-wall excess appeared wider and shorter in 60% suspensions. For suspensions with 1.0 μm beads, the nature of the profile was dependent upon hematocrit. In all cases, at least a small near-wall excess was observed. For hematocrits of 40 and 60%, profiles for 1.0 μm beads were sometimes similar to those for 2.5 μm beads. For the 60% hematocrit and small beads, however, the excess was less than twice the central concentration in two of five trials. These findings are discussed in the context of previous experiments.