Strength of irradiated bone.
A surface of the bone is a site, where the highest mechanical tensions are developed. Therefore, this place has a special importance to provide the strength. The latter depends on a bone tissue atomic/molecular structure. The present report reviews recent results demonstrating how damaged atomic/molecular bonds situated in the surface layer (interface) of the bone have an influence on its strength. The bonds were excited owing to ultraviolet radiation (UR) supplied by a Mercury tube. As the result the strength was decreased. To explore the reason of this phenomenon the atomic force microscopy operated in a tapping mode (AFM) and photoelectron (PE)/exoelectron (EE) analysis was applied. AFM demonstrated a surface topography varied from a homogenize to an island-type under UR. Such a behavior was repeated periodically in monotonically increased radiation exposure. Selective etching of the bone evidenced that reconstruction of the interface layer coupling mineral and organic phases stipulated such a synergetic. EE demonstrated a concentration of destroyed bonds also had a similar regularity depended on exposure. PE measurements discovered responsible for this centres placed at 5.35 and 5.65 eV below a vacuum level.
Dekhtyar
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EEMT Institute, Riga Technical University, Latvia.
D000818:Animals; D001696:Biomechanical Phenomena; D001842:Bone and Bones / Q000503:physiopathology / Q000528:radiation effects*; D002417:Cattle; D066298:In Vitro Techniques; D018625:Microscopy, Atomic Force; D013057:Spectrum Analysis; D014466:Ultraviolet Rays