Skin Cell Renewal The epidermal skin cells possess the activity of continuous self-renewal and replacement of the dead cells. It was estimated that the human epidermis turnover time averages from 40 to 56 days. Unfortunately, the capacity for cell renewal rapidly decline with age [121]. ...
Because the multivariate analysis has to be performed on complete datasets and zero values or fractions of detection limits are inappropriate [75], measurements under the detection limit were imputed using expectation-maximisation-based replacement by the ImpRZilr algorithm. Prior to the PCA, the data...