Fig. 1
From: Introducing the f0% method: a reliable and accurate approach for qPCR analysis
Graphical illustration of the equation parameters. The parameters of the equation could be divided into sigmoidal-related parameters (fm, D, E, and Ci) to fit the amplification curve and linear parameters (a and b) to fit the baseline of the curve. Where fx is the fluorescence of cycle x and x is the cycle number. To illustrate the effect of each of these parameters, the value of only one parameter was varied while maintaining all other parameters to a fixed value (fm = 1, D = 2, E = 1.8, Ci = 20, a = 0, b = 0). All parameters have two plots: linear (left) and logarithmic (right) except for a and b have only linear plots. fm: the maximum predicted fluorescence. D: the rate of efficiency decay, a high value indicates a rapid reduction in efficiency from cycle to cycle. E: the starting efficiency or efficiency in the baseline (note that fixing the value of other parameters—specifically Ci—while plotting curves with variable E necessitates starting with different fluorescence. Thus, low E values were compensated with high starting fluorescence leading to an early rise of their amplification curve). Ci: the inflection cycle is the point that separates the upper and lower parts of the curve and corresponds to the point with the maximum slope. a: baseline slope is the slope of the background noise in case of drifting background. b: the baseline intercept is the starting value of the background noise