Bioengineered Osteoinductive <i>Broussonetia kazinoki</i>/Silk Fibroin Composite Scaffolds for Bone Tissue Regeneration

In this article, <i>Broussonetia kazinoki</i> (BK) powdery extract is utilized to modify the silk fibroin (SF) scaffold and applied to the bone defect area. The BK/SF scaffold is an efficient cell carrier which promotes cell proliferation and osteogenic differentiation of rBMSCs (bone marrow derived mesenchymal stem cells). We confirmed biocompatibility and osteogenic differentiation capacity of BK/SF scaffolds compared to pristine SF scaffold in both <i>in vitro</i> and <i>in vivo</i> evaluation. Gene expression related to osteogenic differentiation and bone regeneration significantly upregulated in the BK/SF scaffold group. The implanted scaffolds were attached well to the surface of the bone defect region and integrated with surrounding tissues without significant inflammatory reaction. Furthermore, almost 45% of bone volume has been recovered at 8 weeks postsurgery, while the SF and control group showed 20% recovery. These results suggest that BK powdery extract incorporated with an SF scaffold might be a suitable substitute for an alternative bone graft for bone regeneration

Ab Initio Study of the Sodium Intercalation and Intermediate Phases in Na_0.44MnO₂ for Sodium-Ion Battery

The Na_0.44MnO₂ structure is a promising cathode material for sodium ion batteries due to a high capacity (∼130 mAh/g) and good cycle performance. In this work, we present the results of density functional theory (DFT) calculations on the structural and electrochemical properties of Na_0.44MnO₂, combined with experiments. Seven intermediate phases and the two-phase reactions among them were found, where the calculated voltage profile agreed well with experiments. We found that the S-shaped tunnel is not empty in the deintercalated Na_0.22MnO₂ structure but has a partial occupancy of sodium ions. The new sodium sites were found in a limited sodium composition range (<i>x</i> = 0.44–0.55) which is attributed to the electrostatic interactions between sodium ions and manganese atoms. The asymmetric lattice evolution in Na_0.44MnO₂ as a function of sodium insertion/deinsertion is shown to be due to the Jahn–Teller effects. On the basis of this interpretation, we suggest that the Cr substitution will reduce the volume change significantly