*2.14. Statistical Analysis*

Statistical analysis was performed using SigmaStat (Version 3.5, Systat Software, San Jose, CA, USA) and IBM SPSS Statistics for Windows (Version 22.0., IBM Corp., Armonk, NY, USA). Comparisons of two experimental groups were performed using Mann–Whitney *U* test, when data were not normally distributed (Shapiro–Wilk's test) otherwise Student *t*-test was utilized. *p* values ≤0.05 were considered as statistically significant.

#### **3. Results**
