Study on gas migration law in goaf under the influence of small faults

In the process of coal mining, small faults can lead to the accumulation of gas in the goaf, forming a gas enrichment zone, which poses a great threat to production safety. Therefore, it is necessary to study the gas migration law in the goaf under the influence of small faults. By using UDEC software to numerically simulate the failure process of the overlying strata in the goaf, the porosity of the overlying strata under the influence of small faults is calculated, and FLUENT software is used to numerically simulate the gas migration law in the goaf considering the influence of small faults during the mining process. Research has shown that: ① the working face is 20 m away from the small fault, and the sliding phenomenon first appears from the top of the small fault, and the displacement of the overlying rock layer in the goaf begins to be affected by the fault; When the working face reaches the fault, due to the sliding of the fault, the hanging wall rock mass undergoes a rotation phenomenon on the fault surface, supporting the rock strata in the goaf. The displacement of the overlying rock collapses significantly, and the rock strata collapse lags behind; The influence range of small faults is limited, and after the working face passes through the small fault for 60 m, the displacement law of the overlying strata in the goaf gradually returns to normal. ② By analyzing the displacement characteristics of the overlying strata in the goaf containing small faults, the displacement of the overlying strata in the goaf and its fitting formula were obtained. The three-dimensional porosity distribution law was calculated: within the range of the caving zone, the porosity of the overlying strata is the highest at four corner positions, and there is also an increase in porosity near the inlet and outlet air tunnels of the faults; Within the fracture zone, except for the position where the fault is close to the inlet and return air roadway, the porosity is relatively low and the change is not significant in other positions. ③ Obtained the gas migration law in the goaf under the influence of small faults: At a distance of 50 m from the fault in the working face, the gas migration in the goaf is almost not affected by the fault; When the working face advances to the fault, the gas migrates along the advantageous escape channel generated by the high porosity overlying rock near the fault towards the deep part of the goaf. At the same time, the gas in the hanging wall also transfers towards the deep part, causing a large amount of gas to accumulate in the lower wall of the fault, which may cause the gas to flow into the working face and return air roadway with the leakage air; When the working face passes through a fault of 50 m, the gas in the goaf continues to transfer towards the vicinity of the upper corner; When the working face passes through a fault of 100 m, the gas migration in the overlying strata of the goaf shows a turning phenomenon, and the gas concentration in the upper corner and lower wall caving zones is high

Engineered myocardial tissues constructed in vivo using cardiomyocyte-like cells derived from bone marrow mesenchymal stem cells in rats

<p>Abstract</p> <p>Background</p> <p>To explore the feasibility of constructing engineered myocardial tissues (EMTs) <it>in vivo</it>, using polylactic acid -co-glycolic acid (PLGA) for scaffold and cardiomyocyte-like cells derived from bone marrow mesenchymal stem cells (BMMSCs) for seeded cells.</p> <p>Methods</p> <p>BMMSCs were isolated from femur and tibia of Sprague-Dawley (SD) rats by density-gradient centrifugation. The third passage cells were treated with 10 μmol/L 5-azacytidine (5-aza) and 0.1 μmol/L angiotensin II (Ang II) for 24 h, followed by culturing in complete medium for 3 weeks to differentiated into cardiomyocyte-like cells. The cardiomyocyte-like cells were seeded into PLGA scaffolds to form the grafts. The grafts were cultured in the incubator for three days and then implanted into the peritoneal cavity of SD rats. Four weeks later, routine hematoxylin-eosin (HE) staining, immunohistochemical staining for myocardium-specific cardiac troponin I (cTnI), scanning electron microscopy and transmission electron microscopy were used to analyze the morphology and microconstruction of the EMTs in host rats.</p> <p>Results</p> <p>HE staining showed that the cardiomyocyte-like cells distributed equally in the PLGA scaffold, and the nuclei arranged in the spindle shape. Immunohistochemical staining revealed that majority of engrafted cells in the PLGA -Cardiomyocyte-like cells group were positive for cTnI. Scanning electron microscopy showed that the inoculated cells well attached to PLGA and grew in 3 dimensions in construct. Transmission electron microscopy showed that the EMTs contained well arranged myofilaments paralleled to the longitudinal cell axis, the cells were rich in endoplasmic reticulum and mitochondria, while desmosomes, gap junction and Z line-like substances were also can be observed as well within the engrafted cells.</p> <p>Conclusion</p> <p>We have developed an in vivo method to construct engineered myocardial tissue. The <it>in vivo </it>microenvironment helped engrafted cells/tissue survive and share similarities with the native heart tissue.</p

Phylogenetic Tree Analysis of the Cold-Hot Nature of Traditional Chinese Marine Medicine for Possible Anticancer Activity

Traditional Chinese Marine Medicine (TCMM) represents one of the medicinal resources for research and development of novel anticancer drugs. In this study, to investigate the presence of anticancer activity (AA) displayed by cold or hot nature of TCMM, we analyzed the association relationship and the distribution regularity of TCMMs with different nature (613 TCMMs originated from 1,091 species of marine organisms) via association rules mining and phylogenetic tree analysis. The screened association rules were collected from three taxonomy groups: (1) Bacteria superkingdom, Phaeophyceae class, Fucales order, Sargassaceae family, and Sargassum genus; (2) Viridiplantae kingdom, Streptophyta phylum, Malpighiales class, and Rhizophoraceae family; (3) Holothuroidea class, Aspidochirotida order, and Holothuria genus. Our analyses showed that TCMMs with closer taxonomic relationship weremore likely to possess anticancer bioactivity.We found that the cluster pattern ofmarine organisms with reported AA tended to cluster with cold nature TCMMs. Moreover, TCMMs with salty-cold nature demonstrated properties for softening hard mass and removing stasis to treat cancers, and species withinMetazoa orViridiplantae kingdomof cold natureweremore likely to contain AA properties.We propose that TCMMs from these marine groups may enable focused bioprospecting for discovery of novel anticancer drugs derived from marine bioresources

DVIS: Decoupled Video Instance Segmentation Framework

Video instance segmentation (VIS) is a critical task with diverse applications, including autonomous driving and video editing. Existing methods often underperform on complex and long videos in real world, primarily due to two factors. Firstly, offline methods are limited by the tightly-coupled modeling paradigm, which treats all frames equally and disregards the interdependencies between adjacent frames. Consequently, this leads to the introduction of excessive noise during long-term temporal alignment. Secondly, online methods suffer from inadequate utilization of temporal information. To tackle these challenges, we propose a decoupling strategy for VIS by dividing it into three independent sub-tasks: segmentation, tracking, and refinement. The efficacy of the decoupling strategy relies on two crucial elements: 1) attaining precise long-term alignment outcomes via frame-by-frame association during tracking, and 2) the effective utilization of temporal information predicated on the aforementioned accurate alignment outcomes during refinement. We introduce a novel referring tracker and temporal refiner to construct the \textbf{D}ecoupled \textbf{VIS} framework (\textbf{DVIS}). DVIS achieves new SOTA performance in both VIS and VPS, surpassing the current SOTA methods by 7.3 AP and 9.6 VPQ on the OVIS and VIPSeg datasets, which are the most challenging and realistic benchmarks. Moreover, thanks to the decoupling strategy, the referring tracker and temporal refiner are super light-weight (only 1.69\% of the segmenter FLOPs), allowing for efficient training and inference on a single GPU with 11G memory. The code is available at \href{https://github.com/zhang-tao-whu/DVIS}{https://github.com/zhang-tao-whu/DVIS}