Fig. 6.

(a) and (b) Individual data points of $T_{\text{skin}}$ and VD for 5 min after thermal stimulation off. (c) A scatter plot that shows the VD change with change of $T_{\text{skin}}$ regardless of the vein size and race. (d) Mean $T_{\text{skin}}$ and VD exponentially decrease with time after removing the thermal stimulation in study A condition ($n=10$). (e) Linear correlation between the $T_{\text{skin}}$ and VD is shown, and the $R^2$ value indicates a good agreement between them.