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To address the issue of severe mine pressure manifestations and difficult-to-control deformation in deep coal seam roadways, an orthogonal numerical simulation experiment was conducted based on the Kastner formula.This experiment examined five factors affecting the stability of roadway surrounding rock: height-to-width ratio, lateral pressure coefficient, depth, cross-sectional shape, and surrounding rock strength.Sensitivity of each factor to roadway deformation and damage was studied using variance analysis and intuitive analysis charts.The stress distribution patterns of elliptical and rectangular roadways under different lateral pressure coefficients and height-to-width ratios were analyzed using the plane elasticity complex variable function theory.Optimal designs for the height-to-width ratio and shape of elliptical and rectangular roadways were developed.The results showed that the main factors affecting the stability of surrounding rock are the strength of the surrounding rock and the lateral pressure coefficient, while depth, cross-sectional shape, and height-to-width ratio are secondary factors.Elliptical roadways exhibit the smallest difference in surrounding rock stress under isotropic stress ratios.Rectangular roadways have lower stress concentration when the width is 5 m and the height-to-width ratio is approximately 0.6.For areas with rapid stress increase in rectangular roadways, an optimized rounded rectangular roadway was designed considering bearing characteristics and cross-sectional utilization, and a calculation formula for the corner radius was established.The optimization performance of this design was verified through numerical simulation.

This study investigated the longitudinal trajectories of peer rejection and their predictive effects on Internet gaming addiction among Chinese children. The sample comprised 818 students from Grades 1 to 3 (M = 8.30, SD = 1.11, 51.3% boys). Peer rejection was assessed using peer nominations in five waves over a period of 2.5 years, and Internet gaming addiction was measured using the Internet Gaming Disorder Scale--Short Form in the fifth wave. We used a growth mixture model to explore the developmental trajectory of peer rejection and identified four heterogeneous developmental trajectories: low-drop, moderate-drop, moderate-rise, and high-rise rejection. The trajectory categories of peer rejection significantly predicted Internet gaming addiction. In particular, the prediction in the moderate-rise rejection group was higher than that in the low-drop rejection group. This study indicates that exploring the prediction of trajectory categories on Internet gaming addiction is necessary and that it is essential for families and schools to help children establish good interpersonal relationships and to reduce the development of addictive behaviors associated with Internet gaming.

Objective·To explore the feasibility of fluorinated decellularized rabbit aorta as a small artificial blood vessel for tissue engineering.Methods·The obtained rabbit aorta was decellularized in combination with Triton X-100, sodium deoxycholate (SD), sodium dodecyl sulfate (SDS), DNAse, and RNAse. Hematoxylin-eosin staining (H-E staining), Masson staining and Verhoff-von Gieson staining were performed in the decellularized group and undecellularized group, respectively. The effect of decellularization was identified by field emission scanning electron microscope, and the morphological changes of decellularized blood vessels were observed. The decellularized rabbit aorta was used as the arterialized artificial small vessel scaffold, and the decellularized small vessel intima was modified with liquid perfluorocarbons coating to prepare a new type of artificial small vessel. The characteristic groups of the artificial small vessel were qualitatively and quantitatively determined. The dissipation time of liquid on the inner surface of the vessel and the flow of liquid on the surface of the vessel tilted at 45° were observed to analyze the hydrophobicity of the vessel. The blood vessels in the decellularized group and the fluorinated group were implanted with platelet-rich plasma, incubated, and observed under an electron microscope to evaluate the antiplatelet aggregation in vitro. The balloon pressure pump was connected to the aorta of the undecellularized group, decellularized group and fluoride group for bursting pressure test.Results·Histological observation of blood vessels showed that the combination could effectively remove cells while retaining collagen and elastic fibers, and there was no damage to the intima under the electron microscope. There was no significant difference in the pressure blasting test among the three groups. In the hydrophobicity experiment, the retention time of water droplets on the membrane of the fluorinated group was over 5 min, and no obvious water marks were left on the 45° inclined plate. In the platelet adhesion test, intimal aggregation activated platelets in the decellularized group, while they were inhibited in the fluorinated group.Conclusion·The decellularized blood vessels have good mechanical properties and physical stability by combined decellularization, and the fluorinated coating makes the blood vessels have good anticoagulant and biocompatibility.

Objective·To construct a bioactivity tissue engineering scaffold with double network cross-linking for cartilage tissue regeneration using an acellular cartilage matrix (ACM) with a natural silk fibroin (SF) biomaterial.Methods·The cell-associated immunogenic components were removed by nuclease digestion, and the extracellular matrix-associated glycoproteins and collagen structures were retained, The efficiency of cartilage tissue decellularization was measured by spectrophotometry by using DNA, histoglycosaminoglycan and collagen quantification kits. ACM and SF were configured into a mixed solution, and the nucleophilic cross-linking reaction with the hydroxyl and carboxyl groups contained in both was carried out by adding ethylene glycol diglycidyl ether. Then it was freeze-dried to make porous bionic scaffolds (n=5). At the same time, porous scaffolds containing only ACM or SF were prepared by the same method (n=5). The microstructure of the scaffolds was observed by scanning electron microscopy (SEM), and the mechanical strength, elastic modulus and resilience of different groups of scaffolds were evaluated by mechanical tests. The internal and external nutrient exchange capacity of the scaffolds was reacted by water absorption rate. Chondrocytes from rabbit ears were isolated, cultured, and seeded on ACM-SF scaffolds. After 1, 4, and 7 days of culture, the adhesion, distribution, and matrix secretion of the cells on the scaffolds were observed by SEM, and the viability status of the cells was determined by double-staining of live and dead cells. CCK-8 method was used to determine the cytotoxicity of the scaffolds. The cells were implanted subcutaneously in nude mice, cultured in vivo for 4 and 8 weeks, and finally removed for histological testing. Differences between groups were tested by One-Way ANOVA. Statistical significance was accepted at a value of P