Application and prospect of coal gangue slurry filling technology

In order to realize in-situ, green and large-scale disposal of coal gangue, coal gangue slurry filling technology, as a new filling technology, has been rapidly developed and applied in recent years. This paper systematically reviews and summarizes the landmark achievements and key technologies of coal gangue slurry filling at different stages, such as the proposal of the technical framework, the formation of the theoretical system of slurry filling, the application of engineering demonstration and the innovation of technology iteration, and forms three filling methods, namely, high-level grouting, low-level grouting and adjacent grouting. The “intervention theory” of coal gangue slurry flow in goaf caving zone and the “three degrees and one field” theory of slurry pipeline transportation have been established, and the first demonstration project of coal gangue underground slurry filling and surface slurry preparation + underground adjacent grouting filling has been successfully carried out at home and abroad; This paper expounds the technical system of coal gangue slurry filling, and discusses the key technical core issues of coal gangue high-efficiency grading crushing, slurry precise preparation, slurry pipeline transportation and end filling, focusing on the process flow of coal gangue crushing, water slurrying of finished gangue powder, slurry pumping preparation and underground target area filling. The technical principles and application scenarios of key equipment such as crushing equipment, screening equipment, metering equipment, mixing equipment and pumping equipment are analyzed; Based on the engineering background of small space, multi-equipment and high capacity of coal gangue slurry filling in Zhangjiamao Coal Mine, the layout of different systems such as surface slurry making, pipeline transportation, underground filling and intelligent control of coal gangue slurry filling was innovatively developed and designed, and the annual filling amount of coal gangue could reach 554 000 tons, forming a demonstration of coal gangue slurry filling engineering. In the future, the coal gangue slurry filling technology will be further studied and developed in the direction of small and lightweight equipment, highly integrated system, iterative and innovative technology, which will provide technical support for the construction of green coal mining technology system and the realization of the national carbon peaking and carbon neutrality goal

Multifunctional PEEK implants via mussel adhesion-mediated assembly for osteoimmune regulation and antibacterial properties

IntroductionPolyetheretherketone (PEEK) is widely recognized for its exceptional mechanical properties and biocompatibility, making it a promising material for orthopedic implants. However, its inherent biological inertia—characterized by poor osteogenic potential, limited antibacterial activity, and excessive immune activation—compromises its clinical performance.MethodsTo address these limitations, we developed a multifunctional PEEK implant (PEEK-PDA-Sr/AMP) through a mussel-inspired self-assembly process, incorporating strontium ions (Sr2+) for dual biological functions and the antimicrobial peptide PMAP-36. A polydopamine (PDA) coating was first applied to enhance microscale surface roughness and hydrophilicity. Subsequently, Sr2+ and AMP were immobilized onto the PDA-modified surface.ResultsThe resulting PEEK-PDA-Sr/AMP implants significantly promoted the adhesion and spatial organization of bone marrow mesenchymal stem cells (BMSCs) and macrophages (BMMs) in vitro. Furthermore, the modified surface facilitated macrophage polarization toward a pro-regenerative phenotype, thereby fostering an osteoimmune microenvironment conducive to osteogenic differentiation of BMSCs. The functionalized implants also exhibited strong antibacterial efficacy against both Staphylococcus aureus and Escherichia coli. In a rat model of osteomyelitis, in vivo evaluations via micro-CT, histology, and immunohistochemistry confirmed that the PEEK-PDA-Sr/AMP implants markedly enhanced immunomodulation, bone regeneration, and osseointegration.DiscussionThis study demonstrates a novel surface bioengineering strategy for constructing multifunctional PEEK implants with improved immunomodulatory, osteogenic, and antibacterial properties, offering a promising solution to meet complex clinical requirements in orthopedic applications

Machine learning models for prediction of postoperative ileus in patients underwent laparoscopic colorectal surgery

Abstract Background: We aimed to assess the performance of machine learning algorithms for the prediction of risk factors of postoperative ileus (POI) in patients underwent laparoscopic colorectal surgery for malignant lesions. Methods: We conducted analyses in a retrospective observational study with a total of 637 patients at Suzhou Hospital of Nanjing Medical University. Four machine learning algorithms (logistic regression, decision tree, random forest, gradient boosting decision tree) were considered to predict risk factors of POI. The total cases were randomly divided into training and testing data sets, with a ratio of 8:2. The performance of each model was evaluated by area under receiver operator characteristic curve (AUC), precision, recall and F1-score. Results: The morbidity of POI in this study was 19.15% (122/637). Gradient boosting decision tree reached the highest AUC (0.76) and was the best model for POI risk prediction. In addition, the results of the importance matrix of gradient boosting decision tree showed that the five most important variables were time to first passage of flatus, opioids during POD3, duration of surgery, height and weight. Conclusions: The gradient boosting decision tree was the optimal model to predict the risk of POI in patients underwent laparoscopic colorectal surgery for malignant lesions. And the results of our study could be useful for clinical guidelines in POI risk prediction.</jats:p

Effect of longitudinal-bending elliptical ultrasonic vibration assistance on electrosurgical cutting and hemostasis

Electrosurgical devices are widely used for tissue cutting and hemostasis in minimally invasive surgery (MIS) for their high precision and low trauma. However, tissue adhesion and the resulting thermal injury can cause infection and impede the wound-healing process. This paper proposes a longitudinal-bending elliptical ultrasonic vibration-assisted (EUV-A) electrosurgical cutting system that incorporates an ultrasonic vibration in the direction of the cut by introducing an elliptical motion of the surgical tip. Compared with a solely longitudinal ultrasonic vibration-assisted (UV-A) electrosurgical device, the EUV-A electrode contacts the tissue intermittently, thus allowing for a cooler cut and preventing tissue accumulation. The experimental results reveal that the EUV-A electrode demonstrates better performance than the UV-A electrode for both anti-adhesion and thermal injury through in vitro experiments in porcine samples. The tissue removal mechanism of EUV-A electrosurgical cutting is modeled to investigate its anti-adhesion effect. In addition, lower adhesion, lower temperature, and faster cutting are demonstrated through in vivo experiments in rabbit samples. Results show that the EUV-A electrode causes lower thermal injury, indicative of faster postoperative healing. Finally, efficacy of the hemostatic effect of the EUV-A electrode is demonstrated in vivo for vessels up to 3.5 mm (equivalent to that of electrocautery). The study reveals that the EUV-A electrosurgical cutting system can achieve safe tissue incision and hemostasis

Multivariate machine learning models for prediction of postoperative intestinal obstruction in patients underwent laparoscopic colorectal surgery: A retrospective observational study

Abstract Background Machine learning may predict postoperative intestinal obstruction (POI) in patients underwent laparoscopic colorectal surgery for malignant lesions.Methods We used five machine learning algorithms (Logistic regression, Decision Tree, Forest, Gradient Boosting and gbm), analyzed by 28 explanatory variables, to predict POI. The total samples were randomly divided into training and testing groups, with a ratio of 8:2. The model was evaluated by the area operation characteristic curve (AUC), F1-Measure, accuracy, recall, and MSE under the receiver.Results A total of 637 patients were enrolled in this study, 122 (19.15%) of them had POI. Gradient Boosting and gbm had the most accurate in training group and testing group respectively.The f1_score of Gradient Boosting was the highest in the training group (f1_score =0.710526), and the f1_score of gbm was the highest in the testing group (f1_score =0.500000). In addition, the results of the importance matrix of Gbdt algorithm model showed that the important variables that account for the weight of intestinal obstruction after the first five operations are time to pass flatus or passage of stool, cumulative dose of rescue opioids used in postoperative days 3 (POD 3), duration of surgery, height and weight.Conclusions Machine learning algorithms may predict the occurrence of POI in patients underwent laparoscopic colorectal surgery for malignant lesions, especially Gradient Boosting and GBM algorithms. Moreover, time to pass flatus or passage of stool, cumulative dose of rescue opioids used during POD 3, duration of surgery, height and weight play an important role in the development of POI.</jats:p

The Adjustment for Entrainment Behavior of Kaolinite in Coal Flotation

The entrainment of gangue particles always increases the ash content of coal flotation concentrate. In the present work, the adjustment for entrainment of kaolinite in coal flotation was studied focusing on the parameters including solid concentration and frother dosage. The results indicated that the ash contents of concentrates were always higher in the early or late stage (flotation time: 0&ndash;30 s or 120&ndash;180 s) than that in the middle stage (flotation time: 30&ndash;120 s). This is mainly because of the mechanical entrainment in the early stage and the entrainment caused by water transportation in the later stage. It has been confirmed that reducing the feed solid concentration and frother dosage effectively decrease mechanical entrainment in the early stage. Furthermore, better flotation results can be obtained under a high solid concentration and frother dosage in the late stage of the flotation process. Therefore, a novel two-stage flotation process was proposed for the coal flotation. A better flotation performance (combustible recovery: 91.28%; ash content: 4.09%) can be achieved by two-stage flotation, compared to the flotation results (combustible recovery: 93.12%; ash content: 5.16%) of the one-stage flotation process

Effectiveness of single loading dose of dexmedetomidine combined with propofol for deep sedation of endoscopic retrograde cholangiopancreatography (ERCP) in elderly patients: a prospective randomized study

Abstract Background Endoscopic retrograde cholangiopancreatography (ERCP) is an advanced endoscopic procedure and requires deep sedation. Deep sedation with dexmedetomidine for the respiratory drive preserved has become popular in recent years. However, the use of dexmedetomidine in elderly patients is controversial because its adverse events are more common. The objective of this study was to investigate the effectiveness of a single loading dose of dexmedetomidine combined with propofol for deep sedation of ERCP in elderly patients. Methods In this prospective randomized trial, 49 elderly patients undergoing ERCP were randomly allocated to the dexmedetomidine (DEX) or propofol (PRO) groups. The single loading dose of dexmedetomidine was set at 0.5 μg/kg at the start of anesthesia induction and loading for 10 min. The primary outcome was the cumulative dose of propofol. Secondary outcomes included time to awake, the frequency of airway interventions, and hemodynamics. Results The intraoperative cumulative dose of propofol was lower in the DEX group (111.0 ± 12.6 μg/kg/min) than the PRO group (143.7 ± 23.4 μg/kg/min) (P &lt; 0.001). There was no statistically significant difference in the time to awake between the two groups. The incidence of artificial airway interventions and hypotension in the PRO group (36%, 60%) were significantly higher than those in the DEX group (4.2%, 16.7%) (P = 0.011, P = 0.003, respectively). In addition, the occurrence of bradycardia increased significantly in the DEX group (58.3%) compared with the PRO group (12%) (P &lt; 0.001). Conclusions The single loading dose of dexmedetomidine combined with propofol can reduce propofol consumption and artificial airway intervention and provide better hemodynamic stability than propofol for deep sedation in elderly patients during ERCP. Trial registration www.chictr.org.cn (Registration number ChiCTR1900028069, Registration date 10/12/2019). </jats:sec