SWCNT dose dependent frequency plots. Panel A presents the SWCNT concentration vs. the time range required for Δf reversal from decreasing to increasing Δf. Only the lowest SWCNT concentrations: 3, 10, 30 and 50 μg/ml exhibited this reversal. Since the reversal was a shallow trough, a range is indicated for each SWCNT concentration on the x-axis. Nonetheless, a linear fit well described this dependence, as is shown. In panel B, the total maximum Δf decrease observed at each SWCNT concentration is plotted vs the log (SWCNT). Again, a linear fit well describes this dependence, as is shown and the SD are indicated.