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Taking Qidong Coal Mine as an example, this paper studies the law of groundwater migration and the characteristics of structural water control in the region, in order to provide reference for advanced precise control and regional prevention of coal mine water disasters. Based on the theory of structural water control and combined with the geological and structural background of Qidong Coal Mine and its mining area and coalfield, the step-by-step control effect of structural water control and the mode of structural water control are studied. The results are as follows: The bedrock formation morphology of Qidong Coal Mine is controlled by Sunan syncline as a whole, partly by Weimiao fault and other structures, and the Cenozoic formation morphology is also indirectly controlled by structures. Under the control of Sunan syncline, Permian coal-bearing sandstone fractured aquifer, Taihui, Ordovician limestone and aquifer IV angle unconformity contact after weathering inside or outside the mine; under the control of Weimiao fault, the aquifer of partial Permian coal-bearing sandstone fractured aquifer in the southern mining area of the mine outcrops again, and contacts with the aquifer IV angle unconformity, which makes the hydraulic connection between the aquifers. Based on the analysis results, it is considered that ① the geological structure controls the underground aquifer water by controlling the formation morphology ; ② Geological structure controls the hydraulic connection between aquifers by controlling the contact between aquifers. In order to further verify the hydraulic connection between aquifers, using the comparative analysis of water level changes and Pearson correlation coefficient, the borehole water level observation results of aquifer IV, Taihui and aquifer IV, Taihui and Ordovician limestone in the southern mining area during the water discharge test and normal water level observation period were analyzed. The results show that: ① During the water discharge test in the southern mining area, the water level changes of aquifer IV (SQ10-14) and Taihui (ST4) are basically synchronous and highly correlated; ② During the normal water level observation, there is a strong correlation between the water level changes of aquifer IV (SQ10), Taihui (ST4) and Ordovician limestone (SO2), and the correlation between different observation holes in the same aquifer is quite different. It is confirmed that, controlled by the structure, there is hydraulic connection in the angular unconformity contact area between the fourth aquifer and the bedrock aquifer in the local area of the mine. The groundwater model system (GMS) and parameter estimation (PEST) are used to study the distribution and runoff law of four water levels. The results show that the four water levels are about−7−−57m, the water level in the south is higher than that in the north, and the hydraulic gradient is larger at the Weimiao fault. The four water-bearing runoff is concentrated in the southwest and central part of the mine. The southwest runoff is northward as a whole, and the central part is mainly east-west runoff. The four water-bearing runoff bypasses the Weimiao fault.

In order to explore the characteristics and laws of coal mine safety accidents in a more in-depth and objective way, the number of coal mine accidents and deaths in 2019 and 2020 published by the State Administration of Coal Supervision and the Coal Mine Safety Network in China were statistically analyzed from different perspectives, and the situation of coal mine safety production in China was analyzed by means of pie chart, bar chart and broken line chart combined with the current domestic situation of China. The analysis shows that: on the whole, the number of coal mine accidents and deaths in China has been at a relatively low level; in terms of accident types, roof, transportation and gas accidents are the main accident types that affect coal mine safety production in China. In terms of spatial distribution, the number of coal mine accidents in China is generally more in the north than in the south. The differences of geological structure and production capacity in the north and the south lead to different causes of the high occurrence of coal mine accidents. In terms of time distribution, the number of accidents in February and March is relatively small, while the number of accidents in June, July and August is frequent and concentrated. From the point of view of the specific time period, downhole work shifts are more prone to accidents.

Based on the analysis of the hydrogeological data of the first mining area in Zhaoxian Coal Mine, by using the research methods of theoretical analysis, similar material test and numerical simulation, the separation layer of overburden strata and water in the mining process of extra-thick coal seam is predicted theoretically. The dynamic development characteristics of vertical and horizontal fractures are analyzed, and the development status of separation layer in the sequential mining of multiple working faces in extra-thick coal seam is discussed. The results show that there is a space for water to separate from the bed at 253.64 m away from the top of the No.3 coal seam; the vertical fracture height increases in two stages including linear growth and stepped growth in the process of the working face advance; the horizontal fracture alternately develops and closes from bottom to top, and the development height of the horizontal fracture is positively related to the advancing distance of the working face; the 0.02 m horizontal separation fissure appears under the Yijun formation caused by the mining of 1307 working face, and the opening of the separation fissure is further expanded or even increased sharply with the mining of 1305 and 1303 working faces in turn; the method of floor water inrush coefficient is introduced to evaluate the risk of separation water inrush in Zhaoxian Coal Mine.

In order to deeply explore the occurrence rules and characteristics of coal mine water disasters in China, reveal the evolution trend of accidents, update accident statistics and analysis, and ensure the timeliness of relevant research, the information about coal mine water disasters in China from 2008 to 2019 published by the State Coal Mine Safety Supervision Bureau, China Coal Mine Safety Network, and coal supervision bureaus of all provinces (autonomous regions and municipalities directly under the central government) were collected using the method of mathematical statistics, this paper analyzes the four dimensions of space, time, water inrush source and mine type. The results show that: Shanxi, Guizhou and Heilongjiang are the cluster areas of water disaster accidents; the frequent occurrence period of water disasters is from March to August every year, and the accidents are relatively concentrated in the periods of 3:00-5:00, 9:00-11:00, 16:00-18:00, 22:00-24:00 every day; old goaf (kiln) water is the main source of water inrush; the number of accidents and the change trend of death toll within the statistical years are divided. They are increasing before peak, decreasing after peak and decreasing gently after peak.

In order to study the special case of down-going coal seam mining accompanied by step faults, the upper and lower working faces and step faults of Chaili Coal Mine are used here as research objects. Overlapping rock movements and their correlation during the close-coal mining process are simulated by similar material simulation tests. The stress variation law was studied, and the research results show that: there is a crack structure and three broken forms in the overburden in single coal seam mining; there is a significant difference between “trapezoidal space” and “triangular space” in the overburden mining in the upper and lower coal seams; coal mining as a whole has the characteristics of “falling with digging, without obvious cycle to step, and difficult to form a beam structure”; and when there is a fault, the transmission of pressure is often affected by the stress barrier of the fault, and the closer it is to the roof, the higher levels of stress concentration.

Nanomaterials with diagnostic and therapeutic functions have exciting potential to reshape the landscape of precision medicine. Impressive progress has been made toward the design and production of innovative theranostic nanomaterials that improve disease care, motivated by their ability to simultaneously provide diagnostic information and therapeutic benefits. Herein, the state‐of‐the‐art theranostic semiconductor quantum dots (QDs) are summarized, and the diverse types of QDs designed for the diagnosis and treatment of different diseases are discussed. The opportunities and benefits of QDs are highlighted throughout using in vitro and in vivo examples aimed at addressing various clinical challenges, including cancer, vascular dysfunctions, microbial infections, and medical tattoos. Over the past several years, this area has experienced enormous growth, particularly in preclinical animal imaging and therapy, which has brought the field closer to reaching human patients. Unfortunately, several barriers to clinical translation remain. Therefore, in addition to summarizing the key results from previous in vivo studies, the lessons learned from these studies are synthesized, perspective on the future steps needed for both fundamental studies and the clinical translation of theranostic QD nanotechnology to inform future QD design is provided. [ABSTRACT FROM AUTHOR]

Chemodynamic therapy as a novel type of chemotherapy can damage the DNA structures and induce cell apoptosis and immunogenic cell death (ICD) through generating reactive oxygen species (ROS) to aggravate oxidative stress. Nonetheless, as an intrinsic antioxidative response of tumor cells, the expression of glutathione (GSH) can be upregulated to maintain the cellular redox balance and protect the tumor cells from ROS-mediated damage. In this context, it is feasible to simultaneously boost ROS generation and GSH depletion in tumor cells; however, the precise delivery and release of GSH scavengers at specific subcellular sites is of great importance. Herein, we propose a GSH-responsive mesoporous organosilica nanoparticle (MON)-based nanomedicine MON-CA-TPP@HA through sequentially covalently attaching triphenylphosphine (TPP) and electrostatically coating hyaluronic acid (HA) onto the surface of cinnamaldehyde (CA)-loaded MONs, known as MON-CA-TPP@HA, which has been demonstrated to be an extremely effective therapeutic strategy for cancer treatment through inducing ICD and apoptosis of breast cancer cells. Systematic in vitro experimental results clearly revealed that the nanomedicine can actively target the tumor cells with the help of HA, subsequently enter the tumor cells, and precisely bind with the mitochondria through TPP residues. Upon cleavaging the disulfide bond in the MONs triggered by over-expressed GSH within tumors, the CA molecules can be released inducing the excessive ROS in situ surrounding the mitochondria to activate oxidative stress to induce apoptosis and ICD of breast cancer cells. The results of the in vivo experiments confirm that the MON-CA-TPP@HA nanomedicine can effectively promote dendritic cell (DC) maturation and CD 8+ T cell activation and regulate the ratio of M1/M2 macrophages, which improve tumor immunosuppressive microenvironment. It is thus believed that the current nanomedicine has paved a new way for future cancer therapy. [ABSTRACT FROM AUTHOR]

For further resource utilization of solid waste steel slag and the reduction in biodiesel production costs, this study used steel slag as a carrier to synthesize a CaO-CeO2/slag solid base catalyst for the effective transesterification of palm oil into fatty acid methyl esters (FAMEs). The synthesis involved a two-step impregnation of steel slag with nitrate of calcium and cerium and thermal activation at 800 °C for 180 min. Then, the catalysts' textural, chemical, and CO2 temperature-programmed desorption properties were characterized. The catalytic activity depended highly on the ratio of Ca-Ce to steel slag mass; the CaO-CeO2/slag-0.8 catalyst showed outstanding performance. Characterization showed that the surface area and total basicity of the Ca-Ce/slag-0.8 catalyst were 3.66 m2/g and 1.289 mmol/g, respectively. The reactivity results showed that FAMEs obtained using 7 wt.% catalyst, 9:1 of methanol-to-palm-oil molar ratio, 180 min reaction duration, and 70 °C reaction temperature was optimum (i.e., 95.3% yield). In addition, the CaO-CeO2/slag-0.8 catalyst could be reused for at least three cycles, retaining 91.2% of FAMEs yield after n-hexane washing. Hence, the catalyst exhibits an excellent potential for cost-effective and environmentally friendly biodiesel production. [ABSTRACT FROM AUTHOR]