Nano-friction behavior and deformation study of hydroxyapatite in ultra-precision polishing process.

Context: In order to study the effect of ultra-precision machining on the surface quality of hydroxyapatite semiconductor materials as well as the material removal mechanism of hydroxyapatite, the mechanical polishing behaviors of hydroxyapatite at different polishing depths were studied by molecular dynamics method. The results show that the subsurface damage of hydroxyapatite increases with increasing polishing depth. The polishing temperature and the polishing force showed a positive correlation with the polishing depth, and the variation of the polishing force was related to the accumulation-release effect of the potential energy of hydroxyapatite material.

MoS/graphene van der Waals heterojunctions combined with two-layered Au NP for SERS and catalysis analyse.

MoS-plasmonic hybrid platforms have attracted significant interest in surface-enhanced Raman scattering (SERS) and plasmon-driven photocatalysis. However, direct contact between the metal and MoS creates strain that deteriorates the electron transport across the metal/ MoS interfaces, which would affect the SERS effect and the catalytic performance. Here, the MoS/graphene van der Waals heterojunctions (vdWHs) were fabricated and combined with two-layered gold nanoparticles (Au NP) for SERS and plasmon-driven photocatalysis analyse.

Noble metal modified ReS nanocavity for surface-enhanced Raman spectroscopy (SERS) analysis.

The rhenium disulphide (ReS) nanocavity-based surface enhanced Raman scattering (SERS) substrates ware fabricated on the gold-modified silicon pyramid (PSi) by thermal evaporation technology and hydrothermal method. In this work, the ReS nanocavity was firstly combined with metal nanostructures in order to improve the SERS properties of ReS materials, and the SERS response of the composite structure exhibits excellent performance in sensitivity, uniformity and repeatability. Numerical simulation reveals the synergistic effect of the ReS nanocavity and the plasmon resonance generated by the metal nanostructures.

Film wrap nanoparticle system with the graphene nano-spacer for SERS detection.

Film wrap nanoparticle system (FWPS) is proposed and fabricated to perform SERS effect, where the Ag nanoparticle was completely wrapped by Au film and the double-layered graphene was selected as the sub-nano spacer. In this system, the designed nanostructure can be fully rather than partly used to generate hotspots and absorb probe molecules, compared to the nanoparticle to nanoparticle system (PTPS) or nanoparticle to film system (PTFS). The optimal fabricating condition and performance of this system were studied by the COMSOL Multiphysics.

[Discrimination of common oral streptococcus with metabonomics method].

Objective: To evaluate the feasibility of identifying oral streptococcus by comparing their metabolic profiling, and to find a convenient and rapid way to discriminate oral microorganisms.

Methods: The pure cultivation of Streptococcus sanguis ATCC 10556 and Streptococcus sobrinus 6715 (reference strain) from solid culture were respectively inoculated in TPY liquid medium. Then the growth quantity was measured periodically by turbidimetry and the growth curves of the inoculated bacteria were completed.

[Preliminary study on the discrimination of putative periodontal pathogens with a metabonomics method].

Objective: To evaluate the feasibility of identifying oral pathogenic bacteria by comparing the metabolic profiling of putative periodontal pathogens and try to find a convenient and rapid way to discriminate oral microorganisms.

Methods: Suspensions of Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum with same density were prepared and cultured respectively at liquid BHI medium. Then the growth quantity was measured periodically through turbidimetry and the growth curves of the inoculated bacteria were completed.