Electron and mechanical properties of bone during heating, evaluated by exoelectron emission and ultrasound

Exoelectron spectroscopy and ultrasound velocity (USV) measurements have been applied to analyse both the electron and mechanical behaviour of compact bone tissue and its main components--collagen and hydroxyapatite (HAP)--in the temperature range 20-80 degrees C. The special exoelectron method with additional IR illumination has been pioneered for the above objective. Thermally induced variations of the electron structure of bone tissue and HAP were manifested at 55 degrees C, but in collagen they were near 75 degrees C. The greatest decrease in USV was at 35-65 degrees C in collagen and at 55-70 degrees C in bone. No changes of USV in HAP were revealed. The coincidence of temperatures of the exoemission maxima and of the USV most expressed gradient in fresh bone and collagen proves the correlation between electron and mechanical behaviour during heating, connected with the partial denaturation of collagen.