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Study travel is an educational activity integrating experiential education and study travel. The choice of destination affects the courses design and development of the activities. This paper conducts a systematic research on the evaluation of study travel destinations with the help of Delphi method and hierarchical analysis, selecting four factors such as facility services, education and teaching, geographic environment and resource characteristics to establish a comprehensive evaluation system of study travel destination. The paper takes the Shuping Danxia scenic spot in Lanzhou as an example. The evaluation results show that the development time of Shuping Danxia Scenic Spot is relatively short, and the study travel and course design have not yet been systemized. It is still necessary to further optimize the overall resource quality with local characteristic culture. The evaluation system established in this paper not only helps study travel educators to choose suitable destinations, but also helps to provide references for potential scenic spots to be built as study travel destinations.

In order to explore highly efficient flame-retardant rigid polyurethane foam (RPUF), phosphorus/nitrogen compounds and expandable graphite (EG) were successfully incorporated into RPUF by a free one-spot method. The combustion results showed that the fire safety of the RPUF samples was remarkably improved by the addition of phosphoric/nitrogen compounds and EG. With the incorporation of 22.4 wt.% phosphorus/nitrogen compounds and 3.2 wt.% EG, the RPUF composites achieved UL-94 V-0 rating. Besides, the total heat release and total smoke release of RPUF composites were reduced by 29.6% and 32.4% respectively, compared to those of the pure RPUF sample. PO• and PO2• together with nonflammable gaseous products were evolved from phosphoric/nitrogen compounds in the gas phase, which quenched the flammable free radicals in the matrix and diluted the concentration of combustible gaseous products generated from PRUF during combustion. The compact char residues which acted as excellent physical barriers were formed by catalysis of EG and phosphoric/nitrogen compounds in the condense phase. The fire hazard of RPUF was significantly reduced by the synergistic effect of phosphorus-nitrogen compounds and EG. This work provides a promising strategy to enhance the fire safety of RPUF. [ABSTRACT FROM AUTHOR]

The extemporaneous combustion of coal remains a major threat to safety in coal mines because such fire accidents result in casualties and significant property loss, as well as serious environmental pollution. This work proposed the fabrication of flame-retardant rigid polyurethane foam (RPUF) containing expandable graphite as char expander/sealant with melamine phosphosphate and 2-carboxyethyl (phenyl)phosphinic acid as char inducer and radical trapping agents. The as-prepared RPUF successfully inhibited coal combustion by forming thermally stable high graphitic content expandable intumescent char sealing over the coal. The RPUF achieved UL-94 V-0 rating in addition to significant reductions in peak heat release, total heat release, and CO and CO2 yields. The external and the internal residual char structure was studied by X-ray photoelectron spectra, Raman spectroscopy, and real-time Fourier transform infrared spectra techniques, and a flame-retardant mode of action has been proposed. This work provides important insight into a facile fabrication of highly efficient and economical flame-retardant RPUF to inhibit the spontaneous combustion of coal. [ABSTRACT FROM AUTHOR]

Objective: This study explored and analyzed the effects of targeted regulation of LATS2 by LncRNA BCAR4 on the proliferation, migration and apoptosis of hepatocellular carcinoma (HCC)., Method: We detected the expression of LncRNA, BCAR4 and LATS2 mRNA in liver hepatocellular carcinoma HepG2 cells and normal hepatocellular cells LO2 by RT-PCR. HepG2 cells were divided into BCAR4-siRNA, NC-siRNA and control groups. We detected the targeted regulation of LncRNA BCAR4 on LATS2 by luciferase gene assay, and measured the proliferation, migration and apoptosis of cells in each group by RT-PCR, MTT, Transwell and flow cytometry, respectively., Results: The relative expression of LncRNA BCAR4 in HepG2 cells was critically higher than that in LO2 cells ( P<0.05 ), while LATS2 mRNA in HepG2 cells was significantly less than that in LO2 cells ( P<0.05 ). Compared with NC siRNA group, the content of luciferase in BCAR4 siRNA group was much higher ( P<0.05 ); The relative expression of LncRNA BCAR4 in BCAR4 siRNA group decreased dramatically than that in NC-siRNA and control group ( P<0.05 ), and the relative expression of LATS2 mRNA increased remarkably than that in NC-siRNA group and control group ( P<0.05 ). The OD value of BCAR4 siRNA group was dramatically higher than that of NC-siRNA group and control group after 48 h and 72 h culture (P<0.05). The quantity of invaded cells in BCAR4 siRNA group was markedly less than that in NC-SIRNA group and control group ( P<0.05 ). Cell apoptosis rate in BCAR4-siRNA group was significantly higher than that of NC-siRNA group and control group ( P<0.05 )., Conclusion: LncRNA BCAR4 can regulate the LATS2 expression, and inhibiting the expression of LncRNA BCAR4 can inhibit proliferation, invasion of HepG2 cells and induce its apoptosis, which finding provides a certain reference for the targeted therapy of liver cancer., Competing Interests: None., (AJTR Copyright © 2021.)