Ratio of every time test results vs. the first test result.

<p>*As the experiments proceeded, a calculated concentration was obtained at each time point for each of the four theoretical concentrations, then, the ratio of Log₁₀(concentration measured at each time, CET)/ Log₁₀(concentration measured at the first time, CFT) are calculated, each concentration was measured three times. The unit of concentration is copies/µl.