Figure 4.

Effect of descriptors on the biological response. The process of variables pruning reveals the presence of six descriptors that significantly influence the biological response of Fe-doped CuO NMs (see Table S7). The sensitivity of the biological response to these descriptors is depicted for (a) 21 days of exposure and (b) 49 days of exposure. In this context, “sensitivity” quantifies the average relative impact of a descriptor within the identified fitting models on the biological response. On the other hand, “% positive response” refers to the likelihood that increasing a descriptor will lead to an increase in the biological parameters (i.e., number of organisms) and vice versa for “% negative response.” For example, a “% positive response = 80% for the x₆ descriptor (21-days exposure)″ means that, considering the explored fitting functions and values of x₆ between the minimum and maximum in the data set, x₆ is positively correlated with the biological response in 80% of the cases. In the remaining 20% of cases, a negative or no correlation is observed instead.