In experiment 3, both T and pH was shifted down after the
critical VCD was achieved. Sudden pH drop might result
with higher shear sensitivity of cells (Petersen et al., 1988).
This case resulted with lowest viable cell density. Since pH
shift was performed through CO2 addition, there might some
adverse impact on cell metabolism and health coming from
high pCO2 that was not explicitly modelled. While model
predictions after T shift for S and G2M phase was good, the
sudden drop in G0G1 later in the culture was not captured
well by the model.