Determining the rational layout parameters of the lateral high drainage roadway serving for two adjacent working faces

To determine the rational layout parameters of the lateral high drainage roadway(LHDR) serving for two adjacent working faces, a mechanical model of the LHDR under mining influence was established, and the overburden fissure, mining-induced stress distribution rules were analyzed. First, the development characteristics of mining-induced overburden fissure and the stress distribution law of the upper section of the working face were analyzed. Second, by analyzing the distribution law of vertical stress at different layers, the lateral distance of the LHDR was determined as 25 m. Third, by analyzing the surrounding rock deformation effect, stress distribution law, and overburden fissure distribution law of the LHDR at the heights of 20, 25, and 30 m away from the roof, the rational horizon of the LHDR was determined to be 25 m. Finally, an example of a LHDR located 25 m above the roof of the No. 2 coal seam and 25 m away from the No. 2-603 working face was presented. Results show that when the No. 2-603 coalface is being mined, the surrounding rocks lag 80 m or even further and the working face tends to be stable. The relative deformations of the roof and floor of the roadway and both of its walls were 583 and 450 mm,respectively. The reduction rate of the roadway section was 21.52%–25.32%. The section of the roadway was sufficient to extract the pressure relief gas in the overburden of the No. 2-605 working face. The average gas concentration and the pure volume at the branch pipeline were 24.8% and 22.3 m^3/min,respectively, showing that the position of high-level boreholes was reasonable.

Impact of intestinal ischemia/reperfusion and lymph drainage on distant organs in rats

AIM:To investigate the impact of intestinal ischemia/reperfusion(I/R) injury and lymph drainage on distant organs in rats.METHODS:Thirty-two Sprague-Dawley male rats,weighing 280-320 g,were randomly divided into blank,sham,I/R,and ischemia/reperfusion and drainage(I/R + D) groups(n = 8).All rats were subjected to 60 min ischemia by clamping the superior mesenteric artery,followed by 120 min reperfusion.The rats in the I/R + D group received intestinal lymph drainage for 180 min.In the sham group,the abdominal cavity was opened for 180 min,but the rats received no treatment.The blank group served as a normal and untreated control.A chromogenic limulus assay kit was used for quantita-tive detection of serum endotoxin.The serum concentrations of tumor necrosis factor-α(TNF-α),interleukin(IL)-6,IL-1β,soluble cell adhesion molecules(sICAM-1),and high mobility group protein box 1(HMGB1) were determined with an enzyme-linked immunosorbent assay kit.Histological evaluations of the intestine,liver,kidney,and lung were performed by hematoxylin and eosin staining and immunohistochemistry.HMGB1 protein expression was assayed by western blot analysis.RESULTS:The serum levels of endotoxin and HMGB1 in the I/R and I/R + D groups were significantly higher than those in the sham group(endotoxin,I/R and I/R + D vs sham:0.033 ± 0.004 EU/mL,0.024 ± 0.003 EU/mL vs 0.017 ± 0.009 EU/mL,respectively,P < 0.05;HMGB1,I/R and I/R + D vs sham:5.473 ± 0.963 EU/mL,4.906 ± 0.552 EU/mL vs 0.476 ± 0.406 EU/mL,respectively,P < 0.05).In addition,endotoxin and HMGB1 were significantly lower in the I/R + D group compared to the I/R group(P < 0.05).The serum inflammatory factors IL-6,IL-1β,and sICAM-1 in the I/R and I/R + D groups were significantly higher than those in the sham group(IL-6,I/R and I/R + D vs sham:41.773 ± 9.753 pg/mL,19.204 ± 4.136 pg/mL vs 11.566 ± 2.973 pg/mL,respectively,P < 0.05;IL-1β,I/R and I/R + D vs sham:144.646 ± 29.378 pg/mL,65.829 ± 10.888 pg/mL vs 38.178 ± 7.157 pg/mL,respectively,P < 0.05;sICAM-1,I/R and I/R + D vs sham:97.360 ± 12.714 ng/mL,48.401 ± 6.547 ng/mL vs 33.073 ± 5.957 ng/mL,respectively;P < 0.05).The serum TNF-α in the I/R group were significantly higher than in the sham group(45.863 ± 11.553 pg/mL vs 18.863 ± 6.679 pg/mL,respectively,P < 0.05).These factors were significantly lower in the I/R + D group compared to the I/R group(P < 0.05).The HMGB1 immunohistochemical staining results showed no staining or apparent injury in the blank group,and slight staining at the top of the microvillus was detected in the sham group.In the I/R group,both the top of villi and the basement membrane were stained for HMGB1 in most areas,and injury in the I/R + D group was less than that in the I/R group.HMGB1 expression in the liver,kidney,and lung of rats in the I/R + D group was significantly lower than the rats in the I/R group(P < 0.05).CONCLUSION:Lymph drainage could block the "gutlymph" pathway,improve intestinal barrier function,and attenuate distant organ injury incurred by intestinal I/R.