Journal of Innovative Optical Health Sciences (Jul 2015)

Entropy and enthalpy for triggering cutaneous erythema

  • Steven L. Jacques,
  • Joseph T. Walsh

DOI
https://doi.org/10.1142/S1793545815500261
Journal volume & issue
Vol. 8, no. 4
pp. 1550026-1 – 1550026-4

Abstract

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The molar entropy (ΔS) and molar enthalpy (ΔH) for the denaturation event that triggers cutaneous erythema was determined to be ΔS = 190 J/(mole K) and ΔH = 146.9 × 103 J/mole. The experiment involved placing heated water against the skin of the forearm, for a range of temperatures and exposure times. Exposing the skin to 45°C for 22 s was at the threshold for producing erythema, which was similar to the threshold for a slight degree of pain.

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