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The present study investigated the spatial ability of adolescent athletes with different sport expertise of axial rotation, providing the cognitive characteristics from both behavior and functional near-infrared spectroscopy (fNIRS) tests. 16 basketball and soccer players, 15 freestyle athletes and 15 runners were selected for spatial ability testing with a three-factor mixed experimental design of 3 (sport type: open high-spatial sport, closed high-spatial sport, closed low-spatial sport) × 2 (rotation angle: 45°, 90°) × 3 (rotation axis: horizontal, vertical, longitudinal). Repeated-measures ANOVA was performed to evaluate the behavioral and fNIRS data of the mental rotation test. The behavioral data showed that the closed high-spatial (CH) group showed better performance than the open high-spatial (OH) and closed low-spatial (CL) group for large angle for every rotation axes. The fNIRS results showed the CH group had greater brain activation than the OH and CL group in the left dorsolateral superior frontal gyrus, precentral gyrus, postcentral gyrus, superior parietal gyrus, left angular gyrus, left precuneus and middle occipital gyrus. The findings provide additional empirical support for relating body rotation experience to spatial cognition performance.

PurposeTo test spatial ability in athletes with different axial rotation experience and analyze their behavioral data to explain the cognitive mechanisms of spatial ability in athletes.MethodsExperiment 1: A total of 147 athletes were selected for the paper-and-pencil mental rotation test (MRT). The athletes were separated according to three sport types: open high-spatial (OH) sport, closed high-spatial (CH) sport, closed low-spatial (CL) sport. Spatial ability testing with a two-factor mixed experimental design of 3 (sport type) × 2 (stimulus type). Experiment 2: In this study, 47 players were selected for computerized mental rotation test, with a three-factor mixed experimental design of 3 (sport type) × 2 (angle: 45°, 90°) × 3 (rotational axis: left–right axis, up–down axis, and front–back axis). Repeated-measures ANOVA was performed to evaluate the data.Results(1) The CH group and OH group outperformed the CL group in the non-embodied task (all ps

Permeability of coal seams is an important indicator for assessing the difficulty of gas seepage and extraction, and its accurate determination holds significant significance. In light of the existing issues with long testing cycles, unstable results, and imperfect models, this research focuses on developing a rapid and accurate method for determining coal seam permeability and the corresponding computational model. Based on the radial unsteady-state gas flow control equation within coal seams and the volume flow equation for gas under different pressure differentials within the coal seam, we have established an injection pressure drop calculation model that utilizes the entire pressure drop dataset for measuring coal seam permeability. The COMSOL numerical simulation software, equipped with the Darcy flow module, is employed to solve the model. To address variables affecting the pressure drop curve in field engineering design, a univariate analysis of the length of the pressure measuring gas chamber is conducted. According to simulation results, the gas chamber length for pressure measurement in boreholes can be designed as 2.0 meters. Field arrangements are made based on the numerical simulation results, and an underground repeated gas injection pressure drop test system is established. This system, in conjunction with coal seam gas occurrence conditions and tunnel conditions, facilitates the drilling of two cross-seam boreholes for each of the two test points. These boreholes are injected with compensatory gas twice, each time exceeding the coal seam gas pressure, to conduct in-situ permeability tests. The testing periods are approximately 6 days and 17 days for the first and second rounds, respectively, with the second round having higher injection pressures. Combined with theoretical derivation, it was verified that the Reynolds numbers of coal seam gas remained within the linear Darcy flow regime during the gas injection pressure drop process, and gas flow within the coal seam adheres to Darcy's law, thus satisfying the assumptions of the calculation model. When compared to traditional methods for calculating coal seam permeability, the results indicate that this method aligns closely with the radial flow rate method, effectively meeting the requirements of practical engineering applications. The testing results of the repeated gas injection pressure drop method are stable and reliable, offering the advantage of rapid determination.

Sole biochar addition or exogenous melatonin application can decrease cadmium (Cd) toxicity in polluted soils and improve plant performance and growth. Yet the additive effects of biochar and melatonin application on plant growth, oxidative stress modulation and Cd absorption remain unclear. We conducted a pot experiment to study the combined effects of melatonin, biochar and Cd stress on pea (Pisum sativum L.) seedling growth, antioxidant enzyme activities, photosynthesis parameters and Cd uptake. Results showed that Cd addition significantly decreased pea growth, chlorophyll content, net photosynthesis rate (Pn), transpiration rate (Tr), stomatal conductance (gs), and increased intercellular CO2 concentration (ci) and oxidant enzyme activities when compared to non-Cd contaminated treatment. Exogenous applications of the biochar or melatonin alone significantly decreased the harmful effects of Cd stress and promoted pea seedling growth. Moreover, soil remediation with biochar could more effectively improve pea growth, chlorophyll contents, and photosynthesis parameters and contribute to Cd immobilisation; the melatonin treatment alone could more effectively increase antioxidant enzyme activities. The treatments of biochar and melatonin showed an additive result and had the largest promoting in pea growth, antioxidant enzyme activities, and lowest Cd contents in pea tissue and soil. These results indicate that the combined use of melatonin and biochar is more effective at reducing Cd uptake by pea tissues and alleviating Cd harm to pea plants.

Abstract Protein‐based drugs have shown unique advantages to treat various diseases in recent years. However, most protein therapeutics in clinical use are limited to extracellular targets with low delivery efficiency. To realize targeted protein delivery, a series of stimuli‐triggered nanoparticle formulations have been developed to improve delivery efficiency and reduce off‐target release. These smart nanoparticles are designed to release cargo proteins in response to either internal or external stimuli at pathological tissues. In this way, varieties of protein‐based drugs including antibodies, enzymes, and pro‐apoptotic proteins can be effectively delivered to desired sites for the treatment of cancer, inflammation, metabolic diseases, and so on with minimal side effects. In this review, recent advances in the design of stimuli‐triggered nanomedicine for targeted protein delivery in different biomedical applications will be discussed. A deeper understanding of these emerging strategies helps develop more efficient protein delivery systems for clinical use in the future.

Abstract The number of mines using roof cutting and pressure relief technology to extract mine deep coal resources is increasing daily. Most of these mines are facing the risk of high gas emission and residual coal spontaneous combustion disasters, and the composite disasters caused by these two risks also threaten the safety of mine production. On the basis of constructing a model for the evolution of porosity and permeability in a single side roof cutting along the gob, this study studied the occurrence locations of gas explosion risk areas, oxidation and heating risk areas, and composite disaster areas under different air supply and gas emission conditions, and summarized the evolution laws of composite disaster risk areas. The research results show that the roof rock collapse caused by roof cutting and pressure relief technology reduces the permeability of porous medium, which significantly reduces the sensitivity of the width of the oxidation temperature rise zone and the composite disaster area to the air supply. The increase in air supply causes the position of the composite disaster risk zone inside the goaf to shift toward the deep part of the goaf, while the width remains basically unchanged. The increase in gas emissions has suppressed the occurrence of coal spontaneous combustion in the goaf, while also keeping the gas concentration in a large area outside the upper limit of gas explosion. The research content enriches the research system of gas and oxygen flow fields in the goaf cutting face, and has positive significance for the promotion and application of goaf cutting technology and the understanding of secondary disasters caused by it.

Submergence stress challenges direct seeding in rice cultivation. In this study, we identified a heat shock protein, NAL11, with a DnaJ domain, which can regulate the length of rice coleoptiles under flooded conditions. Through bioinformatics analyses, we identified cis-regulatory elements in its promoter, making it responsive to abiotic stresses, such as hypoxia or anoxia. Expression of NAL11 was higher in the basal regions of shoots and coleoptiles during flooding. NAL11 knockout triggered the rapid accumulation of abscisic acid (ABA) and reduction of Gibberellin (GA), stimulating rice coleoptile elongation and contributes to flooding stress management. In addition, NAL11 mutants were found to be more sensitive to ABA treatments. Such knockout lines exhibited enhanced cell elongation for coleoptile extension. Quantitative RT-PCR analysis revealed that NAL11 mediated the gluconeogenic pathway, essential for the energy needed in cell expansion. Furthermore, NAL11 mutants reduced the accumulation of reactive oxygen species (ROS) and malondialdehyde under submerged stress, attributed to an improved antioxidant enzyme system compared to the wild-type. In conclusion, our findings underscore the pivotal role of NAL11 knockout in enhancing the tolerance of rice to submergence stress by elucidating its mechanisms. This insight offers a new strategy for improving resilience against flooding in rice cultivation.

The direct hydrogenation of greenhouse gas CO2 to higher alcohols (C2+OH) provides a new route for the production of high-value chemicals. Due to the difficulty of C-C coupling, the formation of higher alcohols is more difficult compared to that of other compounds. In this review, we summarize recent advances in the development of multifunctional catalysts, including noble metal catalysts, Co-based catalysts, Cu-based catalysts, Fe-based catalysts, and tandem catalysts for the direct hydrogenation of CO2 to higher alcohols. Possible reaction mechanisms are discussed based on the structure–activity relationship of the catalysts. The reaction-coupling strategy holds great potential to regulate the reaction network. The effects of the reaction conditions on CO2 hydrogenation are also analyzed. Finally, we discuss the challenges and potential opportunities for the further development of direct CO2 hydrogenation to higher alcohols.

Track smoothness has become an important factor in the safe operation of high-speed trains. In order to ensure the safety of high-speed operations, studies on track smoothness detection methods are constantly improving. This paper presents a track irregularity identification method based on CNN-Bi-LSTM and predicts track irregularity through car body acceleration detection, which is easy to collect and can be obtained by passenger trains, so the model proposed in this paper provides an idea for the development of track irregularity identification method based on conventional vehicles. The first step is construction of the data set required for model training. The model input is the car body acceleration detection sequence, and the output is the irregularity sequence of the same length. The fluctuation trend of the irregularity data is extracted by the HP filtering (Hodrick Prescott Filter) algorithm as the prediction target. The second is a prediction model based on the CNN-Bi-LSTM network, extracting features from the car body acceleration data and realizing the point-by-point prediction of irregularities. Meanwhile, this paper proposes an exponential weighted mean square error with priority inner fitting (EIF-MSE) as the loss function, improving the accuracy of big value data prediction, and reducing the risk of false alarms. In conclusion, the model is verified based on the simulation data and the real data measured by the high-speed railway comprehensive inspection train.

BackgroundInvasive micropapillary carcinoma (IMPC) of the breast is a rare subtype of breast cancer with high incidence of aggressive clinical behavior, lymph node metastasis (LNM) and poor prognosis. In the present study, using the Surveillance, Epidemiology, and End Results (SEER) database, we analyzed the clinicopathological characteristics and prognostic factors of IMPC with LNM, and constructed a prognostic nomogram.MethodsWe retrospectively analyzed data for 487 breast IMPC patients with LNM in the SEER database from January 2010 to December 2015, and randomly divided these patients into a training cohort (70%) and an internal validation cohort (30%) for the construction and internal validation of the nomogram, respectively. In addition, 248 patients diagnosed with IMPC and LNM at the Fourth Hospital of Hebei Medical University from January 2010 to December 2019 were collected as an external validation cohort. Lasso regression, along with Cox regression, was used to screen risk factors. Further more, the discrimination, calibration, and clinical utility of the nomogram were assessed based on the consistency index (C-index), time-dependent receiver operating characteristic (ROC), calibration curve, and decision curve analysis (DCA).ResultsIn summary, we identified six variables including molecular subtype of breast cancer, first malignant primary indicator, tumor grade, AJCC stage, radiotherapy and chemotherapy were independent prognostic factors in predicting the prognosis of IMPC patients with LNM (P < 0.05). Based on these factors, a nomogram was constructed for predicting 3- and 5-year overall survival (OS) of patients. The nomogram achieved a C-index of 0.789 (95%CI: 0.759-0.819) in the training cohort, 0.775 (95%CI: 0.731-0.819) in the internal validation cohort, and 0.788 (95%CI: 0.756-0.820) in the external validation cohort. According to the calculated patient risk score, the patients were divided into a high-risk group and a low-risk group, which showed a significant difference in the survival prognosis of the two groups (P

Abstract Proper braking force distribution strategies can improve both stability and economy performance of hybrid electric vehicles, which is prominently proved by many studies. To achieve better dynamic stable performance and higher energy recovery efficiency, an effective braking control strategy for hybrid electric buses (HEB) based on vehicle mass and road slope estimation is proposed in this paper. Firstly, the road slope and the vehicle mass are estimated by a hybrid algorithm of extended Kalman filter (EKF) and recursive least square (RLS). Secondly, the total braking torque of HEB is calculated by the sliding mode controller (SMC), which uses the information of brake intensity, whole vehicle mass, and road slope. Finally, comprehensively considering driver's braking intention and regulations of the Economic Commission for Europe (ECE), the optimal proportional relationship between regenerative braking and pneumatic braking is obtained. Furthermore, related simulations and experiments are carried out on the hardware-in-the-loop test bench. Results show that the proposed strategy can effectively improve the braking performance and increase the recovered energy through precise control of the braking torque.

Abstract Rapid detection and quantification of outer membrane vesicle (OMV) are of both scientific value and clinical implications. However, limited tools are available for investigations of OMVs. Herein, we report a novel fluorescent probe with aggregation‐induced emission (AIE) characteristics, namely, OEO‐TPE‐MEM (OTM), for OMV detection. OTM emits faintly in an aqueous medium, but its fluorescence could be effectively turned on upon interacting with bacteria bodies and OMVs produced by Gram‐negative bacteria. Notably, OTM could provide quantitative information on bacterial membrane remodeling and OMV secretion and be applied to high‐throughput screening of OMV‐inducing agents. This study presents a powerful AIE probe for imaging and quantitative analysis of bacteria envelop and derived OMVs, which might be applied for evaluating research and clinical antimicrobial materials in future studies.

Multiple nonlinear interactions exist between economic growth, urbanization construction, water resources, and industrial development (EUWI) within a region. To achieve the national goals of ecological protection and high-quality development within the Yellow River Basin of China, it is imperative to establish a clear understanding of the principles that govern these interactions and the level of coupling coordination development that exists within this region. Using data from 2011 to 2020, we quantitatively assessed the operation mechanisms of the EUWI system in nine provinces in the Yellow River Basin. First, a coupling coordination index was developed to measure the coordination relationships within the EUWI system. Next, a random forest method was used to identify the obstacle factors of the coupling coordination development in the EUWI system. Finally, a gray prediction model GM (1,1) was established to predict the development trends of the system in the subsequent five years. Our results show that: (1) the coupling coordination of the EUWI system in the Yellow River Basin improved has steadily improved over the study period, with the southeast region exhibiting a higher level of the coupling coordination than the other areas; (2) gross domestic product, research and development personnel, and the total amount of sewage treated are the main factors affecting the coupling coordination development of the EUWI system; and (3) the coupling coordination indices of the nine provinces will continue to rise from 2021 to 2025, with eight of the nine provinces (excluding Inner Mongolia) expected to reach their peak values in either 2023 or 2025. These results offer valuable insight for China's efforts to promote ecological protection and high-quality development in the Yellow River Basin.

Antibiotic Resistance Genes (ARGs) are widespread in freshwater environments and represent a concealed threat to public health and aquatic eco-system safety. To date, only a limited number of studies have investigated the historical distribution of ARGs and their hosts through the analysis of freshwater sedimentary archives. This research gap constrains our comprehensive of the mechanisms underlying natural bacterial resistance formation during pre-antibiotic era (prior to the 1940s) and the development of human-induced bacterial resistance in post-antibiotic era (since the 1940s). In this study, we examined the vertical distribution patterns of ARGs and their associated hosts within a sedimentary core from a eutrophic lake, employing shotgun sequencing methodology. The findings revealed a marked increase in ARG diversity during post-antibiotic era, and the predominant ARG types identified included those conferring resistance to multidrug, bacitracin, macrolide–lincosamide–streptogramin, beta-lactam, tetracycline, fluoroquinolone, glycopeptide and aminoglycoside, collectively accounting for 78.3%–85.6% of total ARG abundance. A total of 127 ARG subtypes were identified in samples, and 48 ARG subtypes shared across vertical sediment resistome profile with two of them, bac A and bcr A, occurring only in post-antibiotic era. Further, 137 metagenome-assembled genomes (83 species belonging to 12 phyla) were identified as ARG hosts, mainly belonging to the phyla Proteobacteria, Nitrospirota, Chloroflexota, Bacteroidota, Actinobacteriota, Cyanobacteria, and Firmicutes. Significant correlation was found between the diversity of ARG and the concentrations of organic matter and heavy metals, suggesting a common source of contamination. Aside the fact that human-induced eutrophication is a forcing factor acting in parallel to increase ARGs releases in water systems, both being indicators of increased urbanization in the catchment, eutrophication may significantly increase bacterial activity, thereby facilitating the spread of antibiotic-resistant bacteria in environment. This study reveals the marked increased in ARG diversity with the onset of antibiotic use by human societies with potential impact of aquatic ecosystem.

Core competence is the key factor in the competitiveness of enterprises. This study examines whether enterprises with stronger core competence have the ability and motivation to fulfill more corporate social responsibilities. Taking the non-financial companies listed in the A-share market in China from 2010 to 2019 as the research samples, this paper constructs the measurement index of core competence by text analysis method and empirically tests the impact of core competence on corporate social responsibility. We find that the stronger the core competence is, the higher the corporate social responsibility will be, which means core competence can significantly improve corporate social responsibility. This conclusion remains significant after a series of robustness tests. The mechanism test shows that the impact of core competence on corporate social responsibility is realized by enhancing financial strength and increasing external attention. Further research shows that the relationship between core competence and corporate social responsibility are affected by the nature of the enterprise and the degree of market competition. When the enterprise is a non-state-owned enterprise or the industry competition is more intense, the influence of core competence on corporate social responsibility is stronger. This paper reveals the important impact of core competence on corporate social responsibility, which not only enriches the literature on the economic consequences of core competence and the influencing factors of corporate social responsibility but also has a certain practical significance for how to improve corporate social responsibility.

BackgroundAs neoadjuvant chemotherapy is widely used in breast cancer patients, the lymph node ratio has not been fully validated as a prognostic indicator of breast cancer received neoadjuvant chemotherapy. This study was conducted to investigate the prognostic value of lymph node ratio in breast cancer patients received neoadjuvant chemotherapy.MethodsSystematic searches were performed in the PubMed, Embase, and Cochrane Library databases until 15 December 2021 for studies on the association between lymph node ratio and the prognosis of breast cancer after neoadjuvant chemotherapy. Overall survival and disease-free survival were used as outcome events, and hazard ratio was chosen as the parameter to evaluate the correlation. The dose-response relationship was assessed by restricted cubic splines. In the subgroup analyses, which were used to explore potential heterogeneity among the included studies according to study region and sample size. Sensitivity analysis was performed to assess the stability of individual studies, and publication bias was determined with funnel plots, Begg’s test, and Egger's test. All statistical analyses were performed using Stata 15.1.ResultsA total of 12 studies with 4,864 patients were included in this meta-analysis. In this study, high lymph node ratio was significantly associated with decreased overall survival (HR: 4.74; 95%CI: 3.36–6.67; P

BackgroundThere are few studies on young patients with metastatic breast cancer (MBC). This study aims to explore the metastasis pattern and prognosis of young patients with MBC.MethodsA total of 6,336 MBC patients diagnosed in the Surveillance, Epidemiology, and End Results (SEER) database from 2010 to 2015 were selected. They were divided into two age groups: the younger group (≤40 years old) and the older group (>40 years old). χ2 test was used to compare clinicopathological characteristics. Survival differences were compared by Kaplan–Meier analysis. Cox regression models were used to determine the prognostic factors affecting survival. Propensity score matching (PSM) was performed to balance the effects of baseline clinicopathological differences.ResultsFinally, 494 patients (7.8%) who are ≤40 years old and 5,842 patients (92.2%) who are >40 years old were included. In the younger group, the proportion of liver metastasis was significantly higher than that in the older group; the proportion of lung metastasis was significantly lower than that of the older group. Kaplan–Meier analysis showed that the younger group had the best prognosis and the older group had the worst. Youth is an independent protective factor for overall survival (OS). In the younger group, liver metastasis had the best prognosis among all metastatic sites, and the HER2-enriched subtype had the best prognosis among all subtypes.ConclusionsThe disease in young MBC patients is more aggressive but has a better prognosis, especially in liver metastases and the HER2-enriched subtypes.

Abstract RecurIndex, a multigene profiling assay, can predict the risk of local recurrence and distant metastasis in female breast cancer (FBC), but its role in male breast cancer (MBC) remains unclear. In this study, the clinicopathological data of 43 consecutive MBC patients undergoing surgeries between 2009 and 2018 were retrospectively analysed. Their paraffin-embedded tissue sections were examined by RecurIndex test which comprised 2 models: recurrence index for local recurrence (RI-LR) and recurrence index for distant recurrence (RI-DR). Of 43 patients, there were 26 low-risk and 17 high-risk patients assessed by RI-LR, while 17 low-risk and 26 high-risk patients by RI-DR. For RI-LR, tumor N stage showed statistically significant (P

Rail corrugation in heavy-haul railway increases the contact forces between the wheel and the rail and deteriorates the rail condition. Severe corrugation affects railway operational safety. Fast diagnosis techniques allow technical personnel to perform timely maintenance and repair, preventing the quick deterioration of rail corrugation. This paper presents a heavy-haul railway corrugation diagnosis method incorporating the time-frequency analysis with machine learning methods. First, the signal is decomposed into several subsignals by wavelet packet decomposition (WPD). The paper proposes an adaptive short-time Fourier transform (ASTFT) and performs the ASTFT on the subsignals to obtain the optimal resolution time-frequency distribution and compute the corresponding entropy. The dimensionality reduction based on mean entropy is then performed for the high-dimensional data. The training and testing samples are classified using Support Vector Machine (SVM). The adaptive short-time Fourier transform (ASTFT) is incorporated with the Renyi entropy and the particle swarm optimization algorithm, which achieves a better aggregation of the time-frequency distribution and reduces the computation cost. Finally, to assist the repair work and estimate the severity of the corrugation section, the corrugation index is proposed. The corrugation indices for the determined corrugation sections are calculated to measure the severity of the corrugation. Experimental studies performed on the axle-box vertical acceleration data collected from the heavy-haul comprehensive inspection train show that the method presented by this paper achieves higher accuracy when compared with conventional feature classification methods for time-frequency analysis. The accuracy of corrugation recognition for the presented method is 93%.

Understanding species-specific changes in water-use patterns under recent climate scenarios is necessary to predict accurately the responses of seasonally dry ecosystems to future climate. In this study, we conducted a precipitation manipulation experiment to investigate the changes in water-use patterns of two coexisting species (Achnatherum splendens and Allium tanguticum) to alterations in soil water content (SWC) resulting from increased and decreased rainfall treatments. The results showed that the leaf water potential (Ψ) of A. splendens and A. tanguticum responded to changes in shallow and middle SWC at both the control and treatment plots. However, A. splendens proportionally extracted water from the shallow soil layer (0-10cm) when it was available but shifted to absorbing deep soil water (30-60 cm) during drought. By contrast, the A. tanguticum did not differ significantly in uptake depth between treatment and control plots but entirely depended on water from shallow soil layers. The flexible water-use patterns of A.splendens may be a key factor facilitating its dominance and it better acclimates the recent climate change in the alpine grassland community around Qinghai Lake.

This paper investigates the streaming potentials’ behaviors when fluid flows through the micropores in bone. An experimental setup was developed for measuring the streaming potentials between two surfaces of a bone plate specimen. It was found that the streaming potentials measured increased almost linearly with time under a constant fluid pressure gradient, which does not agree with the prediction from the classical theory of streaming potentials. To explain the reasons associated with the results obtained, a theoretical model was proposed in which the electric charge densities on the inner surfaces of the capillary are unevenly distributed. A formula was developed for solving the model, and the solutions demonstrate that nonuniform accumulations of electric charges carried by the fluid on the inner surfaces of the microcanals in bone can induce streaming potentials which linearly increase with time during the driving air pressure holding period. This phenomenon represents the specific characteristics of bone. The solution implies that the streaming potentials in Haversian canals, lacunas and canaliculi are not affected by electro-viscous resistance in the bone fluid.

In order to study the mechanism of the dual side roof cutting technology on the composite disaster of gas and coal spontaneous combustion in goaf, a model for the evolution of porosity and permeability in the dual side roof cutting working face was constructed. The location of the occurrence of the compound disaster of gas explosion and coal spontaneous combustion under the double-sided roof cutting mode was studied, and the sensitivity of the evolution pattern of the compound disaster area to the amount of air supply and gas gush was summarized. The results indicate that the top cutting pressure relief technology significantly reduces the permeability of porous media, and the sensitivity of the goaf on the intake side to airflow disturbances is significantly reduced. As the volume of air supply increases, the distance between the gas explosion risk area and the coal spontaneous combustion risk area gradually decreases, and the probability of composite disaster areas is 0. The increase of air supply and gas emission makes the gas concentration in the middle and deep goaf increase in an exponential function, and the width of the gas explosion risk area increases gradually. When the outflow reaches 40 m3 /min, there is no composite disaster zone, indicating that the rapid increase in outflow inhibits the occurrence of composite disasters. [ABSTRACT FROM AUTHOR]