Single-phase epitaxial films of the monoclinic polymorph of BiVO4 were synthesized by reactive molecular-beam epitaxy under adsorption-controlled conditions. The BiVO4 films were grown on (001) yttria-stabilized cubic zirconia (YSZ) substrates. Four-circle x-ray diffraction, scanning transmission electron microscopy (STEM), and Raman spectroscopy confirm the epitaxial growth of monoclinic BiVO4 with an atomically abrupt interface and orientation relationship (001)BiVO4 ∥ (001)YSZ with [100]BiVO4 ∥ [100]YSZ. Spectroscopic ellipsometry, STEM electron energy loss spectroscopy (STEM-EELS), and x-ray absorption spectroscopy indicate that the films have a direct band gap of 2.5 ± 0.1 eV

A fully functional recovery of peripheral nerve injury remains a major challenge and an unmet clinical need. Recent evidence has reported promising therapeutic effects of mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) in experimental models of tissue injuries and inflammatory diseases, but less is known about their effects on peripheral nerve regeneration. In this study, we investigated the effects of gingiva-derived mesenchymal stem cell (GMSC)-derived EVs on peripheral nerve regeneration of crush-injured mice sciatic nerves. In vivo studies mimicking clinical nerve repair showed that locally wrapping Gelfoam embedded with GMSC-derived EVs at the crush injury site promoted functional recovery and axonal regeneration, which were comparable with effects conferred by direct transplantation of GMSCs. Mechanistically, we showed that GMSC-derived EVs promoted proliferation and migration of Schwann cells, upregulated the protein expressions of c-JUN, Notch1, GFAP (glial fibrillary acidic protein), and SRY (sex determining region Y)-box 2 (SOX2), characteristic genes of dedifferentiation or repair phenotype of Schwann cells, through which pharmacologically blocking c-JUN/JNK (c-JUN N-terminal kinase) activity significantly abrogated GMSC-derived EV-induced upregulation of these Schwann cell dedifferentiation/repair phenotype-related genes. These findings suggest that GMSC-derived EVs promote peripheral nerve regeneration possibly by activating c-JUNgoverned repair phenotype of Schwann cells.

Dynamics and microstructure of the surfactant layer in organically modified silicates and their composites with polystyrene were studied as a function of surfactant loading and temperature in the range relevant for melt intercalation. Site selectivity was achieved by using specifically headgroup-and tail-labeled surfactant EPR spin probes and by applying 31 P MAS NMR to phosphonium surfactants. Bimodal dynamics is observed over a broad range of surfactant loadings and temperatures in both the absence and presence of polymers and correlates with a bimodal distribution of surfactant headgroup distances from the silicate surface. Excess surfactant with respect to the cation exchange capacity of the silicate plasticizes the surfactant layer. Electron spin echo envelope modulation on nanocomposites with ammonium surfactant and deuterated polystyrene demonstrates close contact between the polymer and surfactant tail ends. Surfactant dynamics changes strongly during microcomposite formation, i.e., by embedding stacks of organoclay platelets in a polymer matrix, even if no intercalation takes place.

The development of 1D fiber‐shaped supercapacitors (SCs) with high volumetric energy density is of great significance for miniature wearable electronics, where limiting the device's volume is critical. In this study, a partially unzipped carbon nanotube/reduction graphene oxide (PUCNT/RGO) hybrid fiber with less “dead volume” and a well‐ordered porous structure is fabricated via wet spinning of a mixed partially unzipped oxidized carbon nanotube (PUOCNT)/GO solution and chemical reduction. The spinning solution is of low viscosity and high concentration, which can ensure smooth spinning while reducing the mass transfer during phase separation, thus lessen the “dead volume” derived from isolated pores. Moreover, PUOCNT with 1D and 2D hybrid nanoarchitecture, large specific surface area, and good water solubility can be a more effective spacer to inhibit the restacking of graphene oxide sheets while reducing the spacer itself and the large spacious voids formed “dead volume”. The all‐solid‐state SC assembled from the PUCNT/RGO hybrid fiber exhibits an excellent volumetric energy density of 8.63 mWh cm−3, exceeding the values of previously reported carbon‐based fibers. The findings may open a door for finely controlling the density and pore structure of graphene‐based fiber for applications in high volumetric energy storage via a scalable and efficient process.