Digital biomarkers for Alzheimer's disease: the mobile/ wearable devices opportunity.

Alzheimer's Disease (AD) represents a major and rapidly growing burden to the healthcare ecosystem. A growing body of evidence indicates that cognitive, behavioral, sensory, and motor changes may precede clinical manifestations of AD by several years. Existing tests designed to diagnose neurodegenerative diseases, while well-validated, are often less effective in detecting deviations from normal cognitive decline trajectory in the earliest stages of the disease.

Can composite digital monitoring biomarkers come of age? A framework for utilization.

Introduction: The application of digital monitoring biomarkers in health, wellness and disease management is reviewed. Harnessing the near limitless capacity of these approaches in the managed healthcare continuum will benefit from a systems-based architecture which presents data quality, quantity, and ease of capture within a decision-making dashboard.

Methods: A framework was developed which stratifies key components and advances the concept of contextualized biomarkers.

Improving the estimate of the effective elastic modulus derived from three-point bending tests of long bones.

Three-point bending tests are often used to determine the apparent or effective elastic modulus of long bones. The use of beam theory equations to interpret such tests can result in a substantial underestimation of the true effective modulus. In this study three-dimensional, nonlinear finite element analysis is used to quantify the errors inherent in beam theory and to create plots that can be used to correct the elastic modulus calculated from beam theory.

New resource for the computation of cartilage biphasic material properties with the interpolant response surface method.

Cartilage material properties are important for understanding joint function and diseases, but can be challenging to obtain. Three biphasic material properties (aggregate modulus, Poisson's ratio and permeability) can be determined using an analytical or finite element model combined with optimisation to find the material properties values that best reproduce an experimental creep curve. The purpose of this study was to develop an easy-to-use resource to determine biphasic cartilage material properties.

A new software tool (VA-BATTS) to calculate bending, axial, torsional and transverse shear stresses within bone cross sections having inhomogeneous material properties.

Introduction: This study introduces, validates and demonstrates a new automated software tool (VA-BATTS) to calculate bone stresses within a bone cross section subjected to bending, axial, torsional and transverse shear far-field loading conditions, using quantitative computed tomography (QCT) data.

Methods: A QCT image is imported and processed to generate a 2D finite element (FE) mesh of the bone with inhomogeneous (CT-based) transversely isotropic material properties. Bending and axial stresses are determined using inhomogeneous beam theory; torsional and transverse shear stresses are calculated using a new 2D FE formulation.

Biocompatibility of poly(ethylene glycol)/poly(acrylic acid) interpenetrating polymer network hydrogel particles in RAW 264.7 macrophage and MG-63 osteoblast cell lines.

Hydrogel polymers comprise a novel category of synthetic materials being investigated for use in cartilage replacement. One candidate compound, a poly(ethylene glycol)/poly(acrylic acid) (PEG/PAA) interpenetrating polymer network (IPN), was developed for use in corneal prostheses and was recently engineered for potential orthopedic use. The current study examined the effects of particles of this compound on two cell lines (MG-63 osteoblast-like cells and RAW 264.

Feasibility of using real-time MRI to measure joint kinematics in 1.5T and open-bore 0.5T systems.

Purpose: To test the feasibility and accuracy of measuring joint motion with real-time MRI in a 1.5T scanner and in a 0.5T open-bore scanner and to assess the dependence of measurement accuracy on movement speed.

Three-dimensional finite element modeling of guided ultrasound wave propagation in intact and healing long bones.

The use of guided waves has recently drawn significant interest in the ultrasonic characterization of bone aiming at supplementing the information provided by traditional velocity measurements. This work presents a three-dimensional finite element study of guided wave propagation in intact and healing bones. A model of the fracture callus was constructed and the healing course was simulated as a three-stage process.