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Protocadherin8 (PCDH8), an integral membrane protein, was reported to be a tumor suppressor involved in tumorigenesis in cancers. We aimed to investigate the epigenetic inactivation of PCDH8 and its tumor-suppressor function in nasopharyngeal carcinoma (NPC). Frequent downregulation/silencing of PCDH8 was found in NPC cell lines using semiquantitative PCR. Promoter methylation of PCDH8 was observed in 100% (5/5) of cell lines and 85.3% (35/41) of primary tumors by methylation-specific PCR, but not in normal nasopharyngeal tissues. Treatment of NPC cells with 5-aza-2'-deoxycytidine and/or trichostatin A could restore PCDH8 expression. Ectopic expression of PCDH8 in silenced NPC cells significantly inhibited cell colony formation and cell migration. For the first time, our study demonstrates the epigenetic inactivation of PCDH8 by promoter methylation and its tumor-suppressive function in NPC. Thus, PCDH8 could be identified as a tumor suppressor in NPC.

Searching for a method for low-cost, easily manageable, and scalable production of boron nitride nanosheets (BNNSs) and exploring their novel applications are highly important. For the first time we demonstrate that a novel and effective hydrodynamics method, which involves multiple exfoliation mechanisms and thus leads to much higher yield and efficiency, can realize large-scale production of BNNSs. The exfoliation mechanisms that multiple fluid dynamics events contribute towards normal and lateral exfoliation processes could be applied to other layered materials. Up to ~95% of the prepared BNNSs are less than 3.5 nm thick with a monolayer fraction of ~37%. Compared to the conventional sonication and ball milling-based methods, the hydrodynamics method has the advantages of possessing multiple efficient ways for exfoliating BN, being low-cost and environmentally-friendly, producing high quality BNNSs in high yield and efficiency, and achieving concentrated BNNSs dispersions even in mediocre solvents. It is also shown for the first time that BNNSs can be utilized as fillers to improve the oxygen-atom erosion resistance of epoxy composites which are widely used for spacecraft in low earth orbit (LEO) where atom oxygen abounds. An addition of only 0.5 wt% BNNSs can result in a 70% decrease in the mass loss of epoxy composites after atom oxygen exposure equivalent to 160 days in an orbit of ~300 km. Overall, the demonstrated hydrodynamics method shows great potential in large-scale production of BNNSs in industry in terms of yield, efficiency, and environmental friendliness; and the innovative application of BNNSs to enhancing oxygen-atom erosion resistance of polymeric composites in space may provide a novel route for designing light spacecraft in LEO.

This paper studies the lift and drag experienced by a body in a two-dimensional, viscous, compressible and steady flow. By a rigorous linear far-field theory and the Helmholtz decomposition of the velocity field, we prove that the classic lift formula L = −ρ 0 UΓ φ , originally derived by Joukowski in 1906 for inviscid potential flow, and the drag formula D = ρ 0 UQ ψ , derived for incompressible viscous flow by Filon in 1926, are universally true for the whole field of viscous compressible flow in a wide range of Mach number, from subsonic to supersonic flows. Here, Γ φ and Q ψ denote the circulation of the longitudinal velocity component and the inflow of the transverse velocity component, respectively. We call this result the Joukowski-Filon theorem (J-F theorem for short). Thus, the steady lift and drag are always exactly determined by the values of Γ φ and Q ψ , no matter how complicated the near-field viscous flow surrounding the body might be. However, velocity potentials are not directly observable either experimentally or computationally, and hence neither are the J-F formulae. Thus, a testable version of the J-F formulae is also derived, which holds only in the linear far field. Due to their linear dependence on the vorticity, these formulae are also valid for statistically stationary flow, including time-averaged turbulent flow. Thus, a careful RANS (Reynolds-averaged Navier-Stokes) simulation is performed to examine the testable version of the J-F formulae for a typical airfoil flow with Reynolds number Re = 6.5 × 10 6 and free Mach number M ∈ [0.1, 2.0]. The results strongly support and enrich the J-F theorem. The computed Mach-number dependence of L and D and its underlying physics, as well as the physical implications of the theorem, are also addressed.

The changes in physiology and sensorial qualities of mushroom stored at 2°C for 12 days under high oxygen (100% O 2 , 80% O 2 ) atmosphere and air had been investigated. Respiration rate was suppressed in mushroom in 80% O 2 and 100% O 2 . No significant differences were found between 80% O 2 and 100% O 2 . Weight loss was not more than 1.5% in all treatments. Weight loss and firmness of mushroom held in high oxygen were significantly (P < 0.05) higher than in air. Total soluble solid (TSS) was only slightly affected by high oxygen treatment. High oxygen, especially 100% O 2 treatment was effective at reducing browning degree and electrolyte leakage of mushroom. The surface colour of mushroom changed slightly before tenth day under high oxygen treatment. From day 2 the L-value of mushroom flesh was significantly (P < 0.05) lower under air atmosphere compared with high oxygen treated mushroom. High oxygen, especially 100% O 2 was effective at inhibiting discoloration. The PPO activity of mushroom was significantly (P < 0.05) higher in 100% O 2 compared with air treatment. The POD activity was highest in high oxygen at eighth day, then reduced. High oxygen, especially 100% O 2 was effective at maintaining the quality of mushroom.