Fe-Fe3C Functionalized Few-Layer Graphene Sheet Nanocomposites for an Efficient Electrocatalyst of the Oxygen Reduction Reaction.

Preparation of a high-efficiency, low-cost, and environmentally friendly non-precious metal catalyst for the oxygen reduction reaction (ORR) is highly desirable in fuel cells. Herein, a Fe-Fe3C-functionalized few-layer graphene sheet (Fe/Fe3C/FLG) nanocomposite was fabricated through the vacuum heat treatment technique using ferric nitrate and glucose as the precursors and exhibited a high-performance ORR electrocatalyst. Multiple characterizations confirm that the nanosized Fe particles with the Fe3C interface are uniformly distributed in the FLGs. Electrocatalytic kinetics investigation of the nanocomposite indicates that the electron transfer process is a four-electron pathway. The formation of the Fe3C interface between the Fe nanoparticles and FLGs may promote the electron transfer from the Fe to FLGs. Furthermore, the Fe/Fe3C/FLG nanocomposite not only exhibits high ORR catalytic activity but also displays desirable stability. Consequently, the obtained Fe/Fe3C/FLG nanocomposite might be a promising non-precious, cheap, and high-efficiency catalyst for fuel cells.

Hsa_circ_0081534 facilitates malignant phenotypes by sequestering miR-874-3p and upregulating FMNL3 in nasopharyngeal carcinoma.

OBJECTIVE: Circular RNAs (circRNAs) are connected to nasopharyngeal carcinoma (NPC) development and progression. CircRNA hsa_circ_0081534 (circ_0081534) has been reported to be associated with NPC progression, but its underlying regulatory mechanisms are largely unknown. Thus, the study aims to investigate the mechanism by which circ_0081534 regulates NPC progression. METHODS: Quantitative reverse transcription polymerase chain reaction was conducted to detect circ_0081534 expression. Loss-of-function assays were conducted to evaluate the role of circ_0081534, including 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU) staining, colony formation, flow cytometry, transwell, western blotting, and xenograft assays. Targeting relationship was identified through dual-luciferase reporter assay and RNA immunoprecipitation. RESULTS: Our data exhibited that circ_0081534 was upregulated in NPC samples and cells. Knockdown of circ_0081534 repressed NPC cell proliferation, migration, invasion, EMT, and triggered NPC cell apoptosis. Also, circ_0081534 silencing decreased NPC cell growth in xenograft models. Circ_0081534 functioned as a miR-874-3p sponge, and downregulation of miR-874-3p alleviated the suppressive effects of circ_0081534 silencing on NPC cell malignant phenotypes. MiR-874-3p targeted FMNL3, and circ_0081534 regulated FMNL3 expression through serving as a miR-874-3p sponge. Upregulation of FMNL3 relieved the inhibitory effects of circ_0081534 downregulation on NPC cell malignant phenotypes. CONCLUSION: circ_0081534 interference repressed NPC progression partly by modulating the miR-874-3p/FMNL3 axis.

Instantaneous discharge characteristics and its methane ignition mechanism of coal mine rock damage.

The goaf is the main site of gas explosions in coal mines. A large number of accidents indicate that the occurrence of gas explosion in the goaf is related to the deformation and fracture of the goaf roof. An experimental system was constructed to study the instantaneous discharge characteristics and its ignition mechanism caused by rock damage. The research results reveal that different rocks produce avalanche-like dust clouds ejected outward during the fracture process, and the generation process takes an extremely short time. This dust cloud is not caused by rock fragments heated to incandescence because of friction. The electric sparks produced in the process of rock rupture and the appearance of instantaneous discharge are related not only to the quartz content of the rock, but also to the compressive strength of the rock. The piezoelectric effect of the rock becomes the key factor for the strength or the generation of an electric spark. The instantaneous discharge leaded to the collision of high-energy electrons released during the fracture process with air molecules, ionising, and breaking down the air. When the surrounding medium is gas air within the explosion limit, ionisation is formed and causes gas explosions.