cm−1(related to proteins) and 3200 to 2800 cm−1(related to lipids)47,48. PCA was performed separately for skin and lymph node samples. Score plots and loading plots obtained by PCA analysis as well as mean values from the regions of interest were used for data interpretation....
Interpretation of all other porphyrin ring vibrations coincides with previous works [13, 20–21]. Valence vibrations of the C–C bond between benzene ring and porphyrin macrocycle, ν(Сbenz–Cm), occur in the broad frequency range. For example, in compounds 2 and 5, we assign them to ν...