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In order to study the water inrushing mechanism of floor reinforcement working face and the grouting effect in water abundant mining area of North China Coalfield, by means of mechanical formula derivation, hydro-geological characteristics analysis, micro-seismic monitoring and transient electromagnetic detection results, the superimposed water control mechanism of structure stability key layer of floor and the key layer of failure and penetration in the floor reinforced by grouting is studied, and the model of “two key layers” is formed. The engineering criterion of 2 types and 7 factors that affecting the water control capacity of the “two key layers” is proposed, and the engineering research is carried out in Jiaozuo Mining Area. The results show that the strength of rock mass increases by 40%-159% after grouting, and the maximum tensile strength and shear strength of rock mass reach 5.78 MPa and 38.31 MPa respectively, the floor deformation is reduced, thus reducing the damage and penetration degree of the floor, reaching the engineering criterion of the key layer for the stability and water control of the floor structure. The failure of the key layer of water control through penetration plays a filling and inhibiting role in fracture development, which can prevent confined water inrush. Meanwhile, the insufficient effective waterproof thickness and fault reactivation are the main reasons for the water control failure of the “double key layer”.

To explore the difference of microseismic characteristics in different periods and spaces of the working face and then realize the early warning of water damage, a full-time and space early-warning method for floor water inrush based on microseismic monitoring was proposed based on typical case analysis. The so-called “full-time and space” refers to the 3 time periods of the whole time cycle of the working face, including pre-mining period, advanced-mining period, and mining period, and the 7 evaluation zones of the whole space of the working face. In the first period, based on the engineering information of boreholes and microseismic response characteristics, the expression method of water inrush risk was formed, and the primary abnormal zones were determined, thus realizing the long-term prediction of water inrush risk in the pre-mining period. In the second period, the fixed working face was set up and the microseismic events were repositioned. Based on the nuclear density analysis of the frequency and energy of microseismic events at the “fixed working face”, the water inrush characteristics of the leading influence zone, the lagging influence zone and the lateral influence zone were determined, realizing the water inrush risk early-warning in the advanced mining period. In the third period, the 2D-CE method was introduced to normalize the microseismic events on the plane, the early-warning aquifer was defined, and the roof damage zone, the floor damage zone, and the floor mining damage zone were determined in combination with the frequency of microseismic events and the energy nuclear density analysis, realizing the water inrush risk prediction in the mining period. At the same time, according to the mining verification results, the prediction method in the early phase was modified to serve the water inrush early warning in the subsequent working face, making the prediction results of floor water inrush more accurate in Jiaozuo and Hanxing mining areas.

RationaleWe have hypothesized that post-infarction cardiac remodeling can be influenced by shifts in the balance between intracellular mediators of "pathologic" and "physiologic" hypertrophy. Although alpha1 adrenergic receptors (alpha1-ARs) mediate pro-adaptive hypertrophy during pressure overload, little is known about their role or downstream mediators after myocardial infarction.MethodsWe performed loss-of-function experiments via coronary ligation in alpha1A-AR knockout (AKO) mice. Post-myocardial infarction (MI) remodeling was evaluated via echocardiography, quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis of cardiac fetal gene expression, histologic analysis of myocyte size, post-MI fibrosis and apoptosis, and Western blot analysis of apoptotic regulators.ResultsAlpha1A-AR knockout paradoxically increased post-MI hypertrophy compared to wild type controls (WT), but also increased ventricular dilatation, fibrosis, apoptosis, and 4-week post-MI mortality (64% in AKO vs. 25% in WT, P = 0.02), suggesting a shift toward greater pathologic hypertrophy in the absence of pro-adaptive alpha1A effects. alpha1A-AR knockout increased phospho-p38 levels in the pre-MI myocardium compared to WT (0.55 ± 0.16 vs. 0.03 ± 0.01, P

This study is to investigate the influence of slurry viscosity on the diffusion and filling of slurry during grouting reinforcement. Firstly, based on the newly developed test device, the diffusion process of three kinds of viscosity slurry in the aquifer of confined aquifer was simulated, and the law of slurry diffusion and filling was summarized. Fluent was adopted to simulate the grouting process. The stress distribution and variation law during the filling process of different viscosity slurries was obtained, the abnormal phenomena appearing in the physical test process was explained, and the elastic modulus of the rock mass after different viscosity slurry transformation by ultrasonic measurement was obtained. The results show that: In the process of high-viscosity slurrygouting, the formation of high-stressed cracks in the region is irregularly developed, and the slurry diffusion is deflected to the right; Under the same stress, the elastic modulus(λ)of the rock block is proportional to the viscosity of the slurry(μe), and the λmax=108.07 % (μe=16.67)in the experiment; The medium viscosity slurry has a good transformation effect, and the area of the non-complete filling area is 23.35 %, and no abnormal phenomenon such as slurry accumulation occurs.

Objective: To explore the changes of a series of cytokines before and after percutaneous balloon kyphoplasty (PKP) and prognostic markers for response to PKP. Methods: From 1 January 2019 to 31 May 2019, all single-level lumbar osteoporotic vertebral compression fracture (OVCF) patients diagnosed by MRI who matched the inclusion and exclusion criteria were enrolled in this study. They were classified into the effective group and the ineffective group based on the outcome after PKP. The levels of a series of inflammatory factors and indices of spinal functions were obtained before and after PKP. Results: A total of 72 patients were included in this study, 59 in the effective group and 13 in the ineffective group. The anterior height (AH) and posterior height (PH) were 77.3 ± 11.2% and 91.2 ± 9.3%, respectively, in the effective group after PKP, which were higher than that in the ineffective group (p<.001). While, the Kyphotic angle, visual analog scale (VAS), and Oswestry Disability Index (ODI) score were 9.1 ± 4.3°, 3.1 ± 1.9, and 19.2 ± 4.1 in the effective group, which was lower than that in ineffective group (p<.001). The serum levels of IL-1β, IL-6, and TNF-α were found significantly decreased after treatment in the effective group (p<.05). The logistic regression showed that the levels of IL-6 TNF-α and AH were significant predictor of outcome. Conclusions: Our results demonstrated that PKP can reduce the serum levels of IL-6, IL-1β, and TNF-α, moreover, the IL-6, TNF-α, and AH were significant predictors of outcome. [ABSTRACT FROM AUTHOR]

Water and sand inrush is one of the principal factors that restrict safe and effective production of mining under water body.The threat to soft strata mines with extremely thick coal seam is especially more serious.Caving zone and fissure zone(joint name "two-zone") heights are the basic parameters of water inrush prediction.This paper observes the "two-zone" heights of extra-thick coal seam with slicing full-mechanized caving mining in soft stratum with comprehensive measures of flushing fluid leakage,color borehole TV and core-drilling,and researches the fracture field characteristics of overburden failure through discrete element numerical method.The research results are as follows:under the condition of extra-thick coal seam with slicing full-mechanized caving mining in soft stratum,the stratum movement angle of top slicing working face is about 75°,the ratio is 5.60~5.62 between caving zone and mining height,the ratio is 11.67~12.20 between fissure zone and mining height;the ratio is 4.59~4.71 between caving zone and mining height,the ratio is 8.04~8.58 between fissure zone and mining height in the bottom slicing working face;the height of caving zone increases by 49.41%~50.85% and the height of fissure zone increases by 21.72%~25.38%,but the ratio between caving zone and mining height decreases by 16.19%~18.33%,the ratio between fissure zone and mining height decreases by 29.67%~34.10% when the mining height of the bottom working face is 78.28%~84.71% of the top working face.The research results can provide reference for water damage prediction and the height of safety coal and rock pillar in slicing full-mechanized caving mining face under loose aquifer.

When the working face passes a non-water filled collapse column，the overlaying strata of the working face can be damaged abnormally owing to the mining influence，which inevitably induces water inrush disaster.To study the abnormal failure laws of overlaying strata，the Jingfang coal mine was chosen as the engineering background in the study.A collapse column-surrounding rock fissure mechanical model was built by fully considering the formation of collapse column and geological characteristics of its surrounding rocks.Based on this model，the abnormal failure laws of overlaying strata were analyzed theoretically by combination of physical and numerical simulations.The results indicate that collapse column-surrounding rock fissure field and the mining fissure field were existent in the overburden rock with their own fracture distribution features.Under the influence of mining，some new destruction features were developed under the action of coupled fracture fields and the variation of collapse column-surrounding rock fissures.A concentrated destruction occurred around the collapse column.The new born fissures of bed-separated near the column side and longitudinal broken fissures were interconnected with the above two fissure fields.At the top of the column，the two types of new born fissures could be interconnected.The connected fissures around the collapse column and top of rock mass gradually increased ，which caused the hydraulic conductivity to be enhanced and the risk of water-inrush from roof to be increased.

Due to the problem of stress elastic rapid rise of the borehole wall and strain of borehole wall increase when high pressure water injection was stopped, the ventilation shaft of Jining No.3 coal mine was taken as example, through theoretical analysis, industrial experimental of Z5, Z6 hole water injection combined with low pressure, to explore the feasibility of the two hole joint injection, and water level variation with time of the water level observation hole, strain state of alluvial strata and shaft wall strain before and after water injection were analyzed.The results show that Qunder-3, Z1 hole water level increased significantly by 3.67 m and 4.16 m;Qunder-1、Qunder-4 hole water level rise was relatively small by 1.03 m and 1.77 m.After injection, the water level decreased significantly;24th, 29th, 32nd, 34th alluvial strata strain and corresponding Z1 hole water level fluctuation were synchronous, and 38th strata strain and corresponding Qunder-3 hole water level variation without synchronization was related to strata in the vicinity of alluvium and bedrock related interface;Water injection had a significant effect on ventilation shaft vertical Strain, Qunder-3 hole water level each uplift 1m, the vertical microstrain of the corresponding shaft 172 m level 52V-1, 53V-1 average increased 1.54 and 15.23;Ventilation shaft 172 m level vertical strain variables and the corresponding Qunder-3 hole water level variation was linear correlation, could provide a basis for simple judgment shaft wall strain state.