Evaluation of 3D Pointing Accuracy in the Fovea and Periphery in Immersive Head-Mounted Display Environments.

The coupling between perception and action has seldom been explored in sophisticated motor behaviour such as 3D pointing. In this study, we investigated how 3D pointing accuracy, measured by a depth estimation task, could be affected by the target appearing in different visual eccentricities. Specifically, we manipulated the visual eccentricity of the target and its depth in virtual reality.

On the Failure Initiation in the Proximal Human Femur Under Simulated Sideways Fall.

The limitations of areal bone mineral density measurements for identifying at-risk individuals have led to the development of alternative screening methods for hip fracture risk including the use of geometrical measurements from the proximal femur and subject specific finite element analysis (FEA) for predicting femoral strength, based on quantitative CT data (qCT). However, these methods need more development to gain widespread clinical applications. This study had three aims: To investigate whether proximal femur geometrical parameters correlate with obtained femur peak force during the impact testing; to examine whether or not failure of the proximal femur initiates in the cancellous (trabecular) bone; and finally, to examine whether or not surface fracture initiates in the places where holes perforate the cortex of the proximal femur.

Material mapping strategy to improve the predicted response of the proximal femur to a sideways fall impact.

Sideways falls are largely responsible for the highly prevalent osteoporotic hip fractures in today's society. These injuries are dynamic events, therefore dynamic FE models validated with dynamic ex vivo experiments provide a more realistic simulation than simple quasi-static analysis. Drop tower experiments using cadaveric specimens were used to identify the material mapping strategy that provided the most realistic mechanical response under impact loading.

Morphology based anisotropic finite element models of the proximal femur validated with experimental data.

Finite element analysis (FEA) of bones scanned with Quantitative Computed Tomography (QCT) can improve early detection of osteoporosis. The accuracy of these models partially depends on the assigned material properties, but anisotropy of the trabecular bone cannot be fully captured due to insufficient resolution of QCT. The inclusion of anisotropy measured from high resolution peripheral QCT (HR-pQCT) could potentially improve QCT-based FEA of the femur, although no improvements have yet been demonstrated in previous experimental studies.