Fig. 4
Heatmap with hierarchical cluster analysis of cytotoxic potency of particles in J774A.1 (a) and A549 (b) cells based on cytokine release after 24 h exposure to particles. Inflammatory potency estimate, βI-V for J774A.1 (c) and A549 (d) cells representing the average cytokine potency adjusted for cell viability. The βI-V LO represents the lower estimate (IL-10 and IL-6 potency subtracted from average potency), while βI-V HI is the higher estimate (IL-10 potency subtracted, IL-6 added to average potency). Within the heatmaps, red color represents increased inflammatory potency of particles (increased cytokine/chemokine levels; positive β), whereas green color represents decreased inflammatory potency (negative β)