marginally significantP = 0.07
A nonmonotonic trend could be observed; however, the differences between the first local maximum to the local minimum, and the local minimum to the next local maximum were marginally significant ( r s c ̄ 0.5 mm = 0.0266 ± 0.0032 vs. r s c ̄ 2.5 mm = 0.0165 ± 0.0021, P = 0.07; and r s c ̄ 2.5 mm = 0.0165 ± 0.0021 vs. r s c ̄ 4 mm = 0.0266 ± 0.0054, P = 0.1; green curve in Fig. 6 B ).