Figure 4

Soft component of the bone and its chemical composition. (a) Fraction of soft component of the bone, obtained from the data in Fig. 2b as 1–I_HARD/I_TOT. (b) Average frequency (first spectral moment) of the CH₂CH₃ stretching Raman band in the range 2800—3100 cm⁻¹ of Fig. 2a. (c) Average frequency of the soft Brillouin peak, P_SOFT in Fig. 2a. (d) Average frequency of (Heme + Amine I) Raman band in the range 1565—1720 cm⁻¹ of Fig. 2a. (e) Correlation between relative intensity of Brillouin soft peak and first spectral moment of the CH₂CH₃ Raman band in the range 2800—3100 cm⁻¹. (f) Correlation between Brillouin frequency shift of the soft peak and first spectral moment of (Heme + Amide I) Raman band in the range 1565—1720 cm⁻¹. Different colours are used for data obtained from the different regions of the bone outlined in Fig. 1. Pearson correlation coefficients are reported in the insets.