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Collapse column water bursting occurs from time to time in the coal mining process of North China Type Coalfield in China, which causes great economic loss and personal injury. Therefore, great attention must be paid to the harm of collapse column. 1301 working face and 1306 working face in the west wing of No.1 Mining District of Zhangji Coal Mine in Shanxian County are close to No.2 collapse column. Water bursting risk evaluation must be carried out before mining two working faces to ensure safety production. On the basis of fully analyzing the geological and hydrogeological conditions of the 3up coal seam in the west wing of No.1 Mining Area, the "Three Zones(caving zone, water conducted fracture zone and sagging zone) Theory of Coal Seam Roof", "Strata Movement Theory" and "Water Bursting Coefficient Theory" were used respectively to calculate and evaluate the water bursting risk of No.2 collapse column during the course of mining the 1301 working face and 1306 working face. The results show that: firstly, in the process of mining the 1301 working face, the maximum height of the water conducted fracture zone at the closest position of 1301 working face to No.2 collapse column would be 60.20 m, the water bursting coefficient on the boundary of water conducted fracture zone would be 0.066~0.072 MPa/m, and the water bursting risk of the No.2 collapse column would be smaller; secondly, in the process of mining the 1306 working face, the maximum height of the water conducted fracture zone at the closest position of 1306 working face to No.2 collapse column would be 60.91 m, the water bursting coefficient on the boundary of water conducted fracture zone would be 0.057~0.089 MPa/m, and the water burst risk of the No.2 collapse column would be small. By August 31, 2020, the 1301 working face had been safely mined more than 200 meters long(exceeding over 120 m of the closest position in 1301 working face to No.2 collapse column), and the water bursting did not happen in the working face. This paper can provide a reference for the water prevention and control of similar collapse columns in coal mines.

Retinoid X receptor-α (RXRα) is a kind of nuclear receptor and is a target of cancer prevention and treatment in various types of cancers. Cancer stem cells (CSCs) are regarded as the main cause of carcinoma metastasis, tumor recurrence and chemotherapy resistance. So far, the mechanism how RXRα regulates CSCs remains unknown. In the present study, we found that RXRα was upregulated in head and neck squamous cell carcinoma (HNSCC) tissues and the enriched HNSCC CSCs. Overexpression of RXRα was able to expand the CSC-like properties in HNSCC cells, whereas knockdown of RXRα could repress the stemness respectively. Meanwhile, low doses of cisplatin (CDDP) increased the CSC-like properties and RXRα expression in HNSCC cells. Also, Wnt signaling pathway played a significant role in CDDP-induced CSCs. Simultaneously, curcumin, a plant polyphenol, which is an effective anticancer compound, exhibited an inhibitory effect in the HNSCC CSCs induced by CDDP in vitro and in vivo. Via inhibition of RXRα, curcumin suppressed CSC-like phenotypes induced by CDDP. These findings may suggest a novel mechanism for HNSCC treatment. [ABSTRACT FROM AUTHOR]

Propylene production by n-butene catalytic cracking was studied. Thermodynamic analysis and experimental results showed that a shape-selective catalyst, SAPO-34, with a small pore diameter and weak external acidic sites, can increase the propylene yield and selectivity to 48% and 66%, respectively, from the values of 31% and 36% over a ZSM-5 zeolite by inhibiting the formation of isobutene and other hydrocarbons whose dynamic diameters are larger than isobutene. The optimal temperature for the maximum equilibrium yield of propylene decreases from 600 to 550 °C. The effect of temperature, weight hourly space velocity and time-on-stream in the n-butene cracking process were also studied. [ABSTRACT FROM AUTHOR]

The dimethyl ether to olefins process is very important for converting coal to chemicals. A SAPO-34 molecular sieve with a particle size up to 50 μm has been synthesized with morpholine as the template. The cold model fluidization experiment indicates that the SAPO-34 catalyst with average size of 45–50 μm is of good fluidization properties. After high temperature steam treatment at 1073 K for 8 h, this large fluidizable catalyst showed good reactivity and selectivity for the dimethyl ether to olefins (DTO) reaction in a micro-reactor. X-ray diffraction characterization showed that the structure of the catalyst was maintained well. A fluidized reactor of 50 mm inner diameter was used to carry out the DTO reaction, which showed that the fluidizable SAPO-34 is a selective catalyst for light olefin production. [ABSTRACT FROM AUTHOR]