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Fissure field in goaf of coal mine is the main site of gas disasters and fires. To analyze the inside gas flow law, realistic goaf porosity must be obtained first. Based on the analysis of the different distribution characteristics of “horizontal three zones” and “vertical three zones” of overlying strata fissures in goaf, combined with “O” ring and rock beam theory, caved zone is analyzed and obtained with distribution of bulking factor and distribution function of subsidence of fractured zone, a three-dimensional distribution model of porosity in goaf is established. The applicability of the model is verified through actual cases, and porosity in caved zone is 0.1 to 0.43 and fractured zone is obtained. The porosity reaches the maximum value of 0.31 at a distance of 20 m to 30 m from the bottom plate. The results show that porosity in caved zone is distributed in a “hovel” shape under the influence of bulking factor. From compaction zone along x, y, and z axes to boundary, its value gradually increases from the minimum; in fractured zone, affected by the amount of subsidence in the regular moving zone and the length of the broken rock, the development of the separation layer is large in the surrounding area and small in the middle, and porosity is in a “double hump” shape, and the “bump” is 30 m to 50 m away from the coal face and coal pillar. The porosity is large, as the buried depth becomes shallower, the maximum porosity is closer to the middle in goaf, the basic stability line increases, and the shape of fissures conforms to the distribution of the “O” ring.

CO2 is widely used in coal mine fire prevention and extinguishing based on its property of good inerting effect. Coal mine CO2 fire prevention technology is to transport gaseous, liquid or solid CO2 to the upwind side of the underground fire area. CO2 relies on wind flow to bring it into the fire area for suffocation prevention and firefighting. By reviewing the research progress at home and abroad, the article summarizes the key technologies of coal mines using CO2 for underground fire prevention and extinguishing, which introduces the main research progress in the field from the aspects of CO2 fire prevention and extinguishing technology, inerting mechanism, cooling effect, and the flow and distribution of CO2 in the goaf. The article focuses on the analysis of CO2 fire-fighting technology and its characteristics, and discusses the possible future development direction of CO2 fire-fighting combined with the existing problems. Finally, the article summarizes and prospects the research direction and development trend of CO2 fire-fighting technology.

Background: Mild cognitive impairment (MCI) is the predementia phase of Alzheimer's disease (AD). The intestinal microbiome is altered in MCI and AD, and apolipoprotein E (ApoE) ε4 gene polymorphism is a risk factor for the progression of MCI to AD. This study aims to investigate the improvement in cognitive function of MCI patients with and without ApoE ε4 due to acupuncture and the changes in gut microbiota community composition and abundance in MCI. Methods: This randomized assessor-blind controlled study will enrol MCI patients with and without the ApoE ε4 gene (n = 60/60). Sixty subjects with the ApoE ε4 gene and 60 subjects without the ApoE ε4 gene will be randomly allocated into treatment and control groups in a 1:1 ratio. Intestinal microbiome profiles will be evaluated by 16 S rRNA sequencing of faecal samples and compared between the groups. Results/conclusions: Acupuncture is an effective method to improve cognitive function in MCI. This study will provide data on the relationship between the gut microbiota and the effectiveness of acupuncture in patients with MCI from a new angle. This study will also provide data on the relationship between the gut microbiota and an AD susceptibility gene by integrating microbiologic and molecular approaches. Trial registration: www.chictr.org.cn, ID: ChiCTR2100043017, recorded on 4 February 2021. [ABSTRACT FROM AUTHOR]

Several patients with lung tumors are not eligible for surgical treatment. For those patients, percutaneous lung tumor ablation serves as a minimally invasive alternative to address such tumors. Despite its effectiveness, notable complications associated with this procedure can occur, such as bronchopleural fistula (BPF), which can lead to severe consequences. Therefore, the comprehensive understanding of these complications is of great importance for their safe and efficient management. In the present study, the case of a 73-year-old man with BPF following microwave ablation (MWA) of lung tumor and its clinical management was reported. MWA was performed after the diagnosis of lung cancer. Following ablation, the patient received thoracic drainage and anti-infectious therapy. After verifying the presence of BPF, an endobronchial unidirectional valve (EBV) was implanted into the posterior basal segment bronchus (B10) of the right lower lobe using a bronchoscope. EBV can occlude fistula while allowing drainage of secretions and trapped air. The function contributes to reducing infections around the fistula and promoting healing. The air leakage was stopped five days after EBV implantation and the thoracic drainage tube was then removed. At 86 days after EBV implantation, the pulmonary infection disappeared, while chest computed tomography scan revealed that the pulmonary necrotic cavity was narrowed. EBV implantation may have a higher successful rate compared with other endoscopic treatments for BPF. [ABSTRACT FROM AUTHOR]