Effect of the mechanical properties of carbon-based coatings on the mechanics of cell-material interactions.

The paper presents an influence of the surface mechanical properties of thin-film materials on blood cell adhesion under shear stress conditions. Physical vapour deposited (PVD) coatings i.e. hydrogenated amorphous carbon (a-C:H) doped with nitrogen or silicon have been investigated. The mechanical properties of materials, namely their microhardness and Young's modulus were measured using indentation test with Rockwell indenter. The adhesion efficiency of blood cells in dynamic conditions were analysed using a radial flow chamber. Red blood cells (RBC) were used as representative cells to analyse cell-material interactions. The biomaterial examinations were performed under physiological flow conditions at the single-cell level. The 3D FVM (finite volume method) model of multi-phase radial flow test was developed to reproduce the physical test and to predict distributions of shear stresses and velocity during blood washout with PBS. Cell-material interactions were found to be strongly associated with the mechanical properties of the thin-film material. The decrease in the hardness of the coatings translated into a weaker cell - material interactions.

Polytopic anomalies with agenesis of the lower vertebral column.

We describe clinical, pathological and radiological findings in 15 cases of sporadic and familial lower spine agenesis with additional anomalies of the axial skeleton and internal organs and speculate about the cause and pathogenesis of this malformation complex. We show that all of these findings are defects of blastogenesis, originate in the primary developmental field and/or the progenitor fields, thus representing polytopic field defects. This concept appears applicable in our cases and makes such terms such as "caudal regression syndrome" or "axial mesodermal dysplasia spectrum" redundant.