The effect of surface topography and porosity on the tensile fatigue of 3D printed Ti-6Al-4V fabricated by selective laser melting.

Additive manufacturing (3D printing) is emerging as a key manufacturing technique in medical devices. Selective laser melted (SLM) Ti-6Al-4V implants with interconnected porosity have become widespread in orthopedic applications where porous structures encourage bony ingrowth and the stiffness of the implant can be tuned to reduce stress shielding. The SLM technique allows high resolution control over design, including the ability to introduce porosity with spatial variations in pore size, shape, and connectivity.

Local deformation behavior of surface porous polyether-ether-ketone.

Surface porous polyether-ether-ketone has the ability to maintain the tensile monotonic and cyclic strength necessary for many load bearing orthopedic applications while providing a surface that facilitates bone ingrowth; however, the relevant deformation behavior of the pore architecture in response to various loading conditions is not yet fully characterized or understood. The focus of this study was to examine the compressive and wear behavior of the surface porous architecture using micro Computed Tomography (micro CT). Pore architectures of various depths (~0.

Estimating species richness using environmental DNA.

The foundation for any ecological study and for the effective management of biodiversity in natural systems requires knowing what species are present in an ecosystem. We assessed fish communities in a stream using two methods, depletion-based electrofishing and environmental DNA metabarcoding (eDNA) from water samples, to test the hypothesis that eDNA provides an alternative means of determining species richness and species identities for a natural ecosystem. In a northern Indiana stream, electrofishing yielded a direct estimate of 12 species and a mean estimated richness (Chao II estimator) of 16.

Do Surface Porosity and Pore Size Influence Mechanical Properties and Cellular Response to PEEK?

Background: Despite its widespread use in orthopaedic implants such as soft tissue fasteners and spinal intervertebral implants, polyetheretherketone (PEEK) often suffers from poor osseointegration. Introducing porosity can overcome this limitation by encouraging bone ingrowth; however, the corresponding decrease in implant strength can potentially reduce the implant's ability to bear physiologic loads. We have previously shown, using a single pore size, that limiting porosity to the surface of PEEK implants preserves strength while supporting in vivo osseointegration.

Impact of surface porosity and topography on the mechanical behavior of high strength biomedical polymers.

The ability to control the surface topography of orthopedic implant materials is desired to improve osseointegration but is often at the expense of mechanical performance in load bearing environments. Here we investigate the effects of surface modifications, roughness and porosity, on the mechanical properties of a set of polymers with diverse chemistry and structure. Both roughness and surface porosity resulted in samples with lower strength, failure strain and fatigue life due to stress concentrations at the surface; however, the decrease in ductility and fatigue strength were greater than the decrease in monotonic strength.

Quantification of mesocosm fish and amphibian species diversity via environmental DNA metabarcoding.

Freshwater fauna are particularly sensitive to environmental change and disturbance. Management agencies frequently use fish and amphibian biodiversity as indicators of ecosystem health and a way to prioritize and assess management strategies. Traditional aquatic bioassessment that relies on capture of organisms via nets, traps and electrofishing gear typically has low detection probabilities for rare species and can injure individuals of protected species.

High-strength, surface-porous polyether-ether-ketone for load-bearing orthopedic implants.

Despite its widespread clinical use in load-bearing orthopedic implants, polyether-ether-ketone (PEEK) is often associated with poor osseointegration. In this study, a surface-porous PEEK material (PEEK-SP) was created using a melt extrusion technique. The porous layer was 399.