No abstract

Carbon fiber reinforced thermoplastic polyimide composites were prepared, and the mechanical properties and tribological behaviors at various sliding conditions were systematically investigated. The results showed that the incorporation of carbon fiber not only improves the flexural and tensile properties of polyimide but also greatly promotes the dynamic mechanical properties. Meanwhile, the introduction of carbon fiber greatly enhances the antifriction performance and wear resistance of polyimide at elevated temperatures. Notably, at high temperatures of 180 and 260°C, the composite containing 20vol% carbon fiber exhibits the lowest friction coefficients of 0.054 and 0.1 respectively, accompanied with the lowest wear rates. Moreover, the influence of applied load and sliding speed was also investigated at various temperatures. Scanning electron microscope (SEM) and optical analysis indicate that some lubricating films can be formed on the contact surfaces at high temperatures due to the softening of contact surface and the graphitization of carbon fiber, and the wear mechanism is dominant by adhesive wear. POLYM. COMPOS., 39:E869–E882, 2018. © 2017 Society of Plastics Engineers

In this paper, by electrophoretic deposition of graphene oxide (GO) on the surface of high-strength glass fabric, a new fabric/poly(phthalazione ether sulfone ketone) (PPESK) composites material was successfully fabricated. The effects of GO on the interfacial adhesion, interlaminar shear strength, and tribological properties of the composites were investigated. Because of the addition of GO, the interlaminar shear strength of the composites was enhanced by 36.04%. Besides, the scanning electron microscope observation revealed that the interfacial adhesion between PPESK matrix and glass fabric was greatly improved. Attributing to the good interfacial adhesion, the wear-resistance of the fabric/PPESK composite was greatly enhanced. Moreover, it can be found that the failure location transferred from the interface to the matrix after GO deposition.

Although modern radiotherapy offers excellent local control in the treatment of nasopharyngeal carcinoma (NPC), current therapeutic decisions remain burdensome due to the frequency of local recurrence and treatment failure at distant sites. One potential and promising strategy for the prevention or treatment of cancers is the use of bioactive components of plant origin, including dietary plant products. Herein, we studied one class of these bioactive compounds, grape seed proanthocyanidins (GSPs), and explored their effect on NPC CNE-2 cells, as well as the primary mechanism underlying this effect. Our results revealed that treatment of human NPC CNE-2 cells with GSPs reduced cell viability in a dose- and time-dependent manner, and moreover, markedly induced cell cycle arrest at the G2/M phase, leading to induction of apoptosis. In addition, we found that the underlying mechanism was associated with increased expression of the pro-apoptotic protein Bax, decreased expression of the anti-apoptotic proteins Bcl-2 and Bcl-xL, upregulation of cleaved caspase-3 and cleaved poly(ADP-ribose) polymerase (PRAP) protein, and the loss of mitochondrial membrane potential (MMP) (Δψm). Furthermore, GSPs upregulated the Bcl-2 homology 3 (BH3)-only proteins, Bim and Bad, in a concentration-dependent manner. Taken together, these data supported our hypothesis that, in human NPC CNE-2 cells, GSPs could induce apoptosis through the mitochondrial pathway and ultimately reduce cell viability. Collectively, the results discussed above provide substantive evidence for the potential of GSPs as an effective bioactive phytochemical for the treatment of NPC.