RESUMO
Biomechanical properties of bone depend on the composition and organization of collagen fibers. In this study, Raman microspectroscopy was employed to determine the content of mineral and organic constituents and orientation of collagen fibers in spongy bone in the human head of femur at the microstructural level. Changes in composition and structure of trabecula were illustrated using Raman spectral mapping. The polarized Raman spectra permit separate analysis of local variations in orientation and composition. The ratios of ν2PO4³â»/Amide III, ν4PO4³â»/Amide III and ν1CO3²â»/ν2PO4³â» are used to describe relative amounts of spongy bone components. The ν1PO4³â»/Amide I ratio is quite susceptible to orientation effect and brings information on collagen fibers orientation. The results presented illustrate the versatility of the Raman method in the study of bone tissue. The study permits better understanding of bone physiology and evaluation of the biomechanical properties of bone.
Assuntos
Osso e Ossos/química , Osso e Ossos/fisiologia , Cabeça do Fêmur/química , Cabeça do Fêmur/fisiologia , Análise Espectral Raman , Idoso , Apatitas , Fenômenos Biomecânicos , Cálcio , Colágeno , Feminino , Humanos , FosfatosRESUMO
Polarized resonance Raman spectra of chlorophyll (Chl) b oriented in a mixture of p-methoxybenzylideno-p'-butylaniline (MBBA) and p-ethoxybenzylideno-p'-butylaniline (EBBA) have been measured. The spectra have been analyzed and the second- and fourth-rank order parameters and the orientational distribution function of Chl b are presented.
RESUMO
The molecular ordering of molecules embedded in a uniaxial liquid crystalline system has been considered. In particular, planar Chl a molecules in an MBBA + EBBA mixture have been studied by using polarized resonance Raman spectroscopy. The second- and fourth-rank order parameters and the orientational distribution function of Chl a in the nematic MBBA + EBBA liquid crystalline phase are discussed.