The immune response of bone implants is closely related to the interaction between macrophages and biomaterial surfaces.

Vulnerable populations of wild yak (Bos mutus), the wild ancestral species of domestic yak, survive in extremely cold, harsh and oxygen-poor regions of the Qinghai-Tibetan Plateau (QTP) and adjacent high-altitude regions. In this study, we sequenced and assembled its genomede novo. In total, six different insert-size libraries were sequenced, and 662 Gb of clean data were generated. The assembled wild yak genome is 2.83 Gb in length, with an N50 contig size of 63.2 kb and a scaffold size of 16.3 Mb. BUSCO assessment indicated that 93.8% of the highly conserved mammal genes were completely present in the genome assembly. Annotation of the wild yak genome assembly identified 1.41 Gb (49.65%) of repetitive sequences and a total of 22,910 protein-coding genes, including 20,660 (90.18%) annotated with functional terms. This first construction of the wild yak genome provides a variable genetic resource that will facilitate further study of the genetic diversity of bovine species and accelerate yak breeding efforts.

In this study, two-dimensional Ti₃C₂ nanosheets were employed to improve the tribological and thermo-mechanical properties of epoxy resin. The Ti₃C₂ nanosheets were prepared by ultrasound-assisted delamination of multilayered Ti₃C₂ microparticles, and the Ti₃C₂ nanosheets/epoxy (Ti₃C₂/epoxy) nanocomposites were fabricated through physical blending and curing reaction. Scanning electron microscopy results showed that the Ti₃C₂ nanosheets were dispersed uniformly in the epoxy matrix. Tribological test results showed that the wear rate of Ti₃C₂/epoxy nanocomposites was only 6.61 × 10^–14 m3/(N m) at a 1% mass fraction, which was reduced by 72.1% compared to that of neat epoxy. The morphologies of worn surfaces revealed that the wear form of Ti₃C₂/epoxy nanocomposites transformed gradually from fatigue wear to adhesive wear with the increase of mass fraction of Ti₃C₂ nanosheets. Moreover, the results of thermo-mechanical properties indicated that incorporation of Ti₃C₂ nanosheets effectively improved the storage modulus and glass-transition temperature (T_g) of epoxy resin. This work provides guidance for improving the tribological and thermo-mechanical properties of epoxy resin.

The micromorphology of fillers plays an important role in tribological and mechanical properties of polymer matrices. In this work, a TiO₂-decorated Ti₂C₃ (TiO₂/Ti₃C₂) composite particle with unique micro-nano morphology was engineered to improve the tribological and thermo-mechanical properties of epoxy resin. The TiO₂/Ti₃C₂ were synthesized by hydrothermal growth of TiO₂ nanodots onto the surface of accordion-like Ti₃C₂ microparticles, and three different decoration degrees (low, medium, high density) of TiO₂/Ti₃C₂ were prepared by regulating the concentration of TiO₂ precursor solution. Tribological test results indicated that the incorporation of TiO₂/Ti₃C₂ can effectively improve the wear rate of epoxy resin. Among them, the medium density TiO₂/Ti₃C₂/epoxy nanocomposites gained a minimum wear rate. This may be ascribed by the moderate TiO₂ nanodot protuberances on the Ti₃C₂ surface induced a strong mechanical interlock effect between medium-density TiO₂/Ti₃C₂ and the epoxy matrix, which can bear a higher normal shear stress during sliding friction. The morphologies of worn surfaces and wear debris revealed that the wear form was gradually transformed from fatigue wear in neat epoxy to abrasive wear in TiO₂/Ti₃C₂/epoxy nanocomposites. Moreover, the results of thermo-mechanical property indicated that incorporation of TiO₂/Ti₃C₂ also effectively improved the storage modulus and glass transition temperature of epoxy resin.