Plasma-sprayed HA coatings on metallic implants are widely used for clinical applications. However, typical lamellar structure along with plasma-sprayed coatings usually leads to weak inter-splat adhesion and impair their mechanical properties. In this research, graphene nanosheet (GNS) reinforced HA coatings were fabricated using plasma spray; these GNSs retained their original structure and distributed homogeneously in the as-sprayed coatings. On the basis of instrumented microindentation tests with and without multiple partial unloading, as compared with the monolithic HA coating, the inter-splat friction force increased by ~ 8.7% for the 1.0 wt% GNS/HA coating, and it slightly decreased to ~ 6.5% for the 2.0 wt% GNS/ HA coating due to GNS agglomeration. Meanwhile, the added GNSs contributed greatly to the indentation yield strength of the HA coatings. These results illustrated that these embedded GNSs at splat boundaries are potential in splat-boundary strengthening and resisting splat sliding.

In this paper, the in vitro biocompatibility of graphene film (GF) with osteoblasts was evaluated through cell adhesion, viability, alkaline phosphatase activity, F-actin and vinculin expressions, versus graphite paper as a reference material. The results showed that MG-63 cells exhibited stronger cell adhesion, better proliferation and viability on GF, and osteoblasts cultured on GF exhibited vinculin expression throughout the cell body. The rougher and wrinkled surface morphology, higher elastic modulus and easy out-of-plane deformation associated with GF were considered to promote cell adhesion. Also, the biomineralization of GF was assessed by soaking in simulated body fluid, and the GF exhibited enhanced mineralization ability in terms of mineral deposition, which almost pervaded the entire GF surface. Our results suggest that graphene promotes cell adhesion, activity and the formation of bonelike apatite. This research is expected to facilitate a better understanding of graphene-cell interactions and potential applications of graphene as a promising toughening nanofiller in bioceramics used in load-bearing implants.

Purpose - This paper aims to identify factors that influence the users' word-of-mouth intention (WOMI) regarding mobile apps, focussing on the impacts of technology acceptance model (TAM) and social network theory. Research design, data and methodology - Based on TAM, this study integrates social network theory into the research model. The 317 sets of data collected in a survey were tested against the model using SmartPLS. Results - Our findings suggest the following: 1) Personal innovativeness positively influences perceived usefulness (PU), perceived ease of use (PEU) and perceived enjoyment (PE); 2) PEU affects PU and PE; 3) Both PU and Satisfaction are directly correlated with WOMI. Although PEU and PE has no direct impact on WOMI, they may indirectly affect WOMI via Satisfaction, as PU, PEU and PE all positively influence satisfaction; 4) Network density and network centrality both play a mediating role in the relation between PEU and WOMI. Referral Reward Program have a positive moderating effect on the relation between PU and WOMI. Conclusions - The findings of this study illustrate the traits of Apps that can promote users’ WOMI, as well as the characteristics of people who are more likely to participate in the word-of-mouth process. The findings provide a theoretical basis for app developers to make word-of-mouth a marketing strategy.