We report an experiment that examines the performance of rugby union players and a control group composed of graduate student with no sport experience, in a multiple-object tracking task. It compares the ability of 86 high level rugby union players grouped as Backs and Forwards and the control group, to track a subset of randomly moving targets amongst the same number of distractors. Several difficulties were included in the experimental design in order to evaluate possible interactions between the relevant variables. Results show that the performance of the Backs is better than that of the other groups, but the occurrence of interactions precludes an isolated groups analysis. We interpret the results within the framework of visual attention and discuss both, the implications of our results and the practical consequences.

In recent years, calcium titanate (CaTiO(3)) and carbon-containing materials have gained much attention in a number of biomedical material researches. To maximize the advantages of both materials, we developed a novel alkoxide method to get "calcium titanate with calcium carbonate" (CaTiO(3)-CaCO(3)). The objective was to evaluate the crystallinity and elemental composition of CaTiO(3)-CaCO(3) prepared by alkoxide method, CaTiO(3)-aC elaborated by modified thermal decomposition method, commercially-prepared CaTiO(3), and the effect of these materials on the bone marrow stromal cell. Hydroxyapatite was used as positive control material. We examined the cellular proliferation, osteoblastic differentiation, and mineralization of KUSA/A1 cells cultured with the materials. The results showed that CaTiO(3)-CaCO(3) and CaTiO(3)-aC contained evidence of calcium carbonate enhancing cell proliferation, osteoblastic differentiation, and mineralization. On the contrary, the commercially-prepared CaTiO(3) revealed absence of calcium carbonate with lower cell response than the other groups. The results indicated that calcium carbonate could play a key role in the cell response of CaTiO(3) material. In conclusion, our findings suggest that CaTiO(3)-CaCO(3) could be considered an important candidate as a biomaterial for medical and dental applications.

Abstract:The basic principle of bone induction for tissue engineering is to use stem cells, growth factors and organic matrix. KUSA/A1 cell is an example of bone marrow stromal stem cell, capable of differentiating into osteoblasts, chondrocytes and myotubes under inducing conditions. It has been reported that mature KUSA/A1 osteoblasts cultured in osteogenic condition, were able to induce a few bone formation in collagen hybridized PLGP sponge in vivo. This may be due to their low proliferation potential thereby not being able to obtain sufficient number of cells to promote large tissue repair.Because of this, in order to use KUSA/A1 cells with high cell proliferation activity to induce large amount of new bone, we evaluated whether KUSA/A1 cells in non-induction condition will maintain their immature stage. The result demonstrated that KUSA/A1 cells cultured in α-MEM maintained their immature stage in vitro. We further examined the osteoblastic differentiation under the influence of the host microenvironment in intraperitoneal diffusion chamber. The results indicated that immature KUSA/A1 cells in vivo cell culture differentiated into osteoblasts and produced mineralized bone-like tissue. Finally, we evaluated the effect of honeycomb scaffold to produce abundant bone formation using KUSA/A1 cells implanted in subcutaneous tissues of SCID mice. 1x10 6 KUSA/A1 cells with honeycomb scaffold showed abundant new bone formation. While, 5x106 KUSA/A1 cells alone showed only few small islands of new bone formation. This study support that KUSA/A1 cell is a good candidate as stem cells for basic research in bone tissue engineering.

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