Molybdenum oxide/nickel molybdenum oxide heterostructures hybridized active platinum co-catalyst toward superb-efficiency water splitting catalysis.

A new catalyst has been developed that utilizes molybdenum oxide (MoO3)/nickel molybdenum oxide (NiMoO4) heterostructured nanorods coupled with Pt ultrafine nanoparticles for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) toward industrial-grade water splitting. This catalyst has been synthesized using a versatile approach and has shown to perform better than noble-metals catalysts, such as Pt/C and RuO2, at industrial-grade current level (≥1000 mA·cm-2). When used simultaneously as a cathode and anode, the proposed material yields 10 mA·cm-2 at a remarkably small cell voltage of 1.55 V and has shown extraordinary durability for over 50 h. Density functional theory (DFT) calculations have proved that the combination of MoO3 and NiMoO4 creates a metallic heterostructure with outstanding charge transfer ability. The DFT calculations have also shown that the excellent chemical coupling effect between the MoO3/NiMoO4 and Pt synergistically optimize the charge transfer capability and Gibbs free energies of intermediate species, leading to remarkably speeding up the reaction kinetics of water electrolysis.

De novo dual functional 3D scaffold using computational simulation with controlled drug release.

A novel and facile synthesis is made of cotton-like three-dimensional (3D) fibrous scaffold containing spatiotemporally defined patterns of simvastatin (SIM) optimized for angiogenesis-coupled osteogenesis. Herein, we demonstrate the 3D fiber deposition mechanism in detail during the electrospinning process via computer simulation. The 3D fibrous scaffolds were functionalized with hydroxyapatite nanoparticles (HA - NPs) to induce the biomineralization process mimicking the natural apatite layer. The morphology, physiochemical properties, biomimetic mineralization, and drug release of the as-fabricated 3D fibrous scaffolds of simvastatin-loaded poly (ɛ-caprolactone) poly (glycerol-sebacate) hydroxyapatite nanoparticles (3D - PGHS) were investigated. The effects of simvastatin on the osteogenic differentiation of human mesenchymal stem cells (hMSCs) and angiogenesis in human umbilical vein endothelial cells (HUVECs) were assessed. The results showed that the 3D - PGHS both enhanced the expression of osteogenic markers including ALP, RUNX2, and COLA1 in hMSCs, and promoted the migration and tube formation of HUVECs. This finding demonstrates the potential of 3D scaffold-loaded SIM as a putative point-of-care therapy for tightly controlled tissue regeneration.

Analysis of stress distribution around total hip stems custom-designed for the standardized Asian femur configuration.

In total hip replacement (THR), bone resorption related to the foreign body reaction around the implant causes bonding failure at the bone-prosthesis interface and adversely affects the function and longevity of femoral implants. Stress shielding is thought to be one of the possible biomechanical factors that causes bone resorption, and is related to prosthesis design. We therefore investigated stress distribution at the bone-implant interface of implant models custom-fitted to Asian individuals, using a finite-element method. Based on the standard geometry of Asian femurs, we designed four different custom-fitted implant stems and applied boundary conditions, including a stationary loading of 1750 N. Even though stress shielding was observed for all four different prostheses, the custom-designed implant with a stepped groove in the proximal-medial region had the largest maximum principal stress distribution along paths on the bone-implant interface. This implant type also showed the highest maximum principal stress distribution at the proximal (0.308 MPa), mid (0.872 MPa) and distal (12.981 MPa) regions of the cortical surface of the femur. In conclusion, the implant design with a stepped groove in the proximal-medial region showed an overall increase in stress distribution due to minimization of stress shielding afforded by the reduced effective area in the bone-implant interface. Therefore, this hip implant type could be a possible geometry to remain functional over the long term in THR patients.