Albizzia chinensis (Osbeck) Merr extract YS ameliorates ethanol-induced acute gastric ulcer injury in rats by regulating NRF2 signaling pathway.

BACKGROUND: Around the world, there is a high incidence of gastric ulcers. YS, an extract from the Chinese herb Albizzia chinensis (Osbeck) Merr, has potential therapeutic applications for gastrointestinal diseases. Here we elucidated the protective effect and underlying mechanism of action of YS on gastric ulcer in rats injured by ethanol. METHODS: The ethanol-induced gastric ulcer rat model was used to assess the protective effect of YS. A pathological examination of gastric tissue was performed by H&E staining. GES-1 cells damaged by hydrogen peroxide were used to simulate oxidative damage in gastric mucosal epithelial cells. Endogenous NRF2 was knocked down using small interfering RNA. Immunoprecipitation was used to detect ubiquitination of NRF2. Co-immunoprecipitation was used to detect the NRF2-Keap1 interaction. RESULTS: YS (10 and 30 mg/kg, i.g.) significantly reduced the ulcer index, decreased MDA level, and increased SOD and GSH levels in gastric tissues damaged by ethanol. YS promoted NRF2 translocation from cytoplasm to nucleus and enhanced the NQO1 and HO-1 expression levels in injured rat gastric tissue. In addition, YS regulated NQO1 and HO-1 via NRF2 in H2O2-induced oxidative injured GES-1 cells. Further studies on the underlying mechanism indicated that YS reduced the interaction between NRF2 and Keap1 and decreased ubiquitylation of NRF2, thereby increasing its stability and expression of downstream factors. NRF2 knockdown abolished the effect of YS on MDA and SOD in GES-1 cells treated with H2O2. CONCLUSION: YS reduced the NRF2-Keap1 interaction, promoting NRF2 translocation into the nucleus, which increasing the transcription and translation of NQO1 and HO-1 and improved the antioxidant capacity of rat stomach.

Overburden failure and water-sand mixture outburst conditions of weakly consolidated overlying strata in Dananhu No.7 coal mine.

This study presents a case of weakly consolidated strata developed in Dananhu No.7 coal mine. Using a combination of numerical simulation, field measurement comparison, and the critical hydraulic gradient criterion, we investigate the overburden failure and the risk possibility of water-sand mixture inrush during excavation. The following are the principal findings: (1) Weakly consolidated rocks have poor physical characteristics, particularly when they are mudded and disintegrated after encountering water, which may become a favorable source of water-sand inrush; (2) The water-conducting zone develops to a height of 160.5 m with a crack-mining ratio of 15.29 times, extending upward to Toutunhe Formation aquifer. The predictions are consistent with measurements in adjacent mines with similar geological conditions; (3) Cracks without larger subsidence are developed at the front edge of the mining direction, and some parallel stepped cracks behind the goaf could be easily observed. Ground subsidence along the goaf center finally displays a symmetrically wide-gentle U shape; (4) The critical hydraulic gradient of Toutunhe Formation aquifer, aquifer above 3# coal seam, and aquifer of 3#-7# coal seam in Xishanyao Formation is 1.314, 1.351, and 1.380, the actual value is 0.692, 2.089, and 7.418 accordingly. It is inferred water-sand mixture outburst will not occur in Toutunhe Formation aquifer, while the potential risk exists in the aquifers of Xishanyao Formation. Through drainage and depressurization projects, a water-sand mixture outburst accident does not occur during excavation. This study reveals the overburden failure characteristics and the initiation mechanism of water-sand inrush in weakly cemented strata, as well as the internal relationship between them, which provides new research ideas for safe operation in other mining areas with similar geological conditions. The research work has certain practical guiding significance.

An improved risk zoning method of bed-separation water inrush in underground coal mines: a case study in Ningxia, China.

Bed-separation water inrush (BSWI) is a new type of coal mine disaster that has caused serious damage. The shortcomings of previous studies on this topic are as follows: 1) most studies focused on the BSWI mechanism, evolution, and control methods, and there is a lack of research on BSWI risk assessment methods and 2) previous risk assessment studies ignored the factors of the water yield property. First, based on the proposed BSWI engineering geological model, three first-order factors are proposed: 1) separation space between layers, 2) water production characteristics, and 3) water resistance effect. Then, eight secondary factors are determined: 1) production thickness (MT), 2) hard rock thickness (HRT), 3) improved lithology index (ILCI), 4) core recovery (CR), 5) aquifer depth (AD), 6) drilling fluid consumption (DFC), 7) protective layer thickness (PLT), and 8) self-healing potential index (SPI). Subsequently, the corresponding weights are calculated, and the multifactor superposition method is used to draw the BSWI risk map. The area is divided into three risk grades: low, medium, and high. The results are validated by observations of BSWI accidents and bed-separation water exploration and discharge boreholes in the study area. The proposed method can be used to effectively prevent BSWI disasters in other coal mines with similar geological conditions.

Method for Evaluating Fault Hydraulic Conductive Property and Its Application in Shandong, China.

Coal remains the largest contributor to the energy structure of China. However, coal production is frequently threatened by groundwater inrush accidents caused by hydraulically conductive faults. Despite the threat of such accidents, research on methods for evaluating fault hydraulic conductive property without hydraulic tests has seldom been conducted. Many faults exist in coal mines in Shandong, China. However, due to economic and technical limitations, hydrological tests are rarely performed and can be performed on only a few faults. The hydraulic conductive property of many faults is unknown, which has prevented serious groundwater inrush accidents and casualties from being avoided. Using accessible geological exploration data, we propose a method for evaluating fault hydraulic conductive property in the Jining coalfield, Shandong, China. Mudstone smearing, lithologic contact relations on the fault plane, geostress, water pressure, plastic deformation of mudstone, and the argillaceous content of the fault zone were selected as factors, and six quantitative indicators were proposed: the shale gouge ratio (SGR), lithologic juxtaposition diagram (LJD), fault closure coefficient (FCC), water pressure coefficient (WPC), mudstone deformation coefficient (MDC), and shale smear factor (SSF). The fuzzy analytic hierarchy process (FAHP) was applied to calculate the weights and establish lateral and vertical hydraulic conductive property (L and V) evaluation models for faults. The fault hydraulic conductivities were then classified as weak, medium, or strong. The hydrochemical experiments and the limited number of exposed faults were used for validation. Hence, the evaluation models were considered effective at determining the hydraulic conductive property of faults in the Jining coalfield, China.