Reprogramming of macrophages toward an M1 phenotype is a novel strategy to induce anticancer immunity. However, the regulatory mechanisms of M1 macrophage polarization and its functional roles in nasopharyngeal carcinoma (NPC) progression need to be further explored. Here we found that SPLUNC1 was highly expressed and responsible for M1 macrophage polarization. JAK/STATs pathway activation was involved in SPLUNC1-mediated M1 macrophage polarization. Importantly, regulation of SPLUNC1 in macrophages affected CM-mediated influence on NPC cell proliferation and migration. Mechanistically, USP7 deubiquitinated and stabilized TRIM24, which promoted SPLUNC1 expression via recruitment of STAT3 in M1 macrophages. Depletion of TRIM24 inhibited M1 macrophage polarization, which facilitated NPC cell growth and migration. However, over-expression of USP7 exhibited the opposite results and counteracted the tumorigenic effect of TRIM24 silencing. Finally, the growth and metastasis of NPC cells in vivo were repressed by USP7-induced M1 macrophage polarization via modulating TRIM24/SPLUNC1 axis. USP7 delayed NPC progression via promoting macrophage polarization toward M1 through regulating TRIM24/SPLUNC1 pathway, providing evidence for the development of effective antitumor immunotherapies for NPC.

To investigate the impact of moisture in various states on the adsorption of CH₄, N₂, and CO₂ by coal, this study conducted isothermal adsorption experiments on dry coal for moisture and on coal with varying moisture content for CH₄, N₂, and CO₂. The results revealed that coal moisture adsorption progresses through four stages: monolayer adsorption, multilayer adsorption, cluster formation, and condensation into free moisture filling pores. The presence of moisture in coal varies across these stages, with its impact on CH₄, N₂, and CO₂ adsorption decreasing as moisture content increases. As the moisture content rises, the adsorption constants (a and b values) progressively decline and eventually level off. Based on differences in coal moisture states, delineated by a relative humidity of 0.50 (corresponding to a moisture content of 2.39% in experimental samples), adsorption potential theory identified low moisture content stages where the monolayer and multilayer adsorption potentials for moisture (E₁ = 4.99 kJ/mol, E₂ = 39.71 kJ/mol) exceeded those for CH₄, N₂, and CO₂, suggesting competitive adsorption effects. In the high-water content stage, the mesoporous structural fractal dimension D₂ of the coal samples was found to be 2.77, nearly reaching 3, as determined through liquid nitrogen adsorption experiments and fractal dimension theory. This suggests that the intricate pore structure leads to water condensation, free water formation, and pore blockage, making it the primary factor influencing the adsorption of CH₄, N₂, and CO₂ in coals, which is inherently linked to the characteristics of coal.

To study the differences between various gas injection sources in the process of coal seam methane replacement, experimental research was conducted to study the influences of different gas injection sources and gas injection ratios on coal seam methane replacement by considering the strong adsorption gas CO₂ and the weak adsorption gas N₂. The experimental results show that the temperature rise effect of the CO₂ injection gas is greater and lasts longer than that of the N₂ injection gas in the process of coal seam methane replacement by gas injection, and the temperature rise can promote the desorption of adsorbed methane well. However, due to the different effects of gas compressibility, the increase in gas pressure caused by injecting N₂ under the same conditions is higher than that of CO₂; due to the strong adsorption of CO₂, the gas pressure after injecting CO₂ continues to decrease slowly. From the displacement effect, the adsorbability of the injection source gas has a significant effect on the displacement rate and injection-placement ratio, while the injection ratio has a significant effect on CO₂ displacement but not on N₂ injection. From the experimental results, for N₂ injection, the effects of coal seam methane replacement by gas injection can be enhanced by improving the gas injection method and process; for CO₂ injection, the effects of coal seam methane replacement by gas injection can be improved by the following two aspects: gas injection volume and gas injection time.

Injecting N₂ to displace methane is an effective way to enhance coalbed methane drainage, and the influence radius of this process is an important factor in borehole arrangement. To determine reasonable spacing between injection boreholes and discharge boreholes, experimental and theoretical studies were carried out. The change of rule for the influence radius was determined based on the flow rate changes at the discharge boreholes when injecting gas into a coal seam in the field. Based on gas seepage-diffusion theory, a model for injecting N₂ to displace coalbed methane was established. Through numerical simulation, the time characteristics of the influence radius were analyzed. The results show the following: Under different gas injection pressure conditions, the influence radius increases exponentially as injection time increases, but the rate of increase of the influence radius decreases gradually. For the same injection time, the higher the injection pressure, the wider the influence radius will be. After obtaining field results, regression analysis was applied to analyze the numerical results of gas injection at different pressures, and then, the quantitative relationship between the injection influence radius r, the injection time t, and the injection pressure p was found. According to the results calculated using this formula at an injection pressure of 0.5 MPa, the optimum spacing between boreholes was determined to be 1.5 m at the Shigang Coal Mine. The analysis of reasonable spacing between injection and extraction boreholes at different injection pressures shows that the reasonable spacing between boreholes was linearly correlated with gas injection pressures. This study has important theoretical and practical significance for the spacing between boreholes in a reasonable arrangement when injecting N₂ to displace methane.