Table 2 Summary of hydration dynamics of the initial hydration process according to the first order kinetics model.

From: Skin hydration dynamics investigated by electrical impedance techniques in vivo and in vitro

Method

First order kinetics (Fig. 3A)

Degree of hydration, \({\theta }_{h}\), (Fig. 3B) at time \({t}_{h}\)

\(k\)

Hydration time,\({t}_{h}\)

R2

HP conductance in vivo

0.0136

4

0.991

97%

HP conductance in vitro

0.0087

6

0.993

95%

NE conductance in vivo

0.0051

10

0.831

96%

NE conductance in vitro

–

–

–

–

NE MIX in vivo

0.0095

5

0.997

91%

NE MIX in vitro

–

–

–

–

NE 1 kHz in vivo

0.0062

8

0.764

93%

NE 1 kHz in vitro

–

–

–

–

4E conductance in vitro

0.0049

10

0.963

88%

4E MIX in vitro

0.0034

15

0.904

97%

4E 1 kHz in vitro

0.0080

6

0.964

88%

  1. First order rate constants, \(k\) (s−1), obtained by linear regression (see Fig. 3A) and estimated hydration times, \({t}_{h}\), (in minutes) required to reach 95% conversion, i.e. \(\alpha\) = 0.95 in Eq. (2). The degree of hydration, \({{\varvec{\theta}}}_{{\varvec{h}}}\), was calculated with Eq. (3) (see Fig. 3B) together with the hydration time,\({t}_{h}\). If the degree of hydration is close to 95%, it supports the first order kinetics model with 95% conversion.
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