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The interaction of super-large section chamber group in deep and close-distance condition will lead to stress concentration and wide failure range of surrounding rock, especially under dynamic disturbances. In this paper, numerical simulation software FLAC3D is used to establish the calculation model based on the field condition of coal gangue separation system in Longgu Coal Mine. The deformation and failure evolution of chamber group under different chamber spacing and dynamic loads are studied by using built-in dynamic module. The simulation results show that: With the decrease of chamber spacing, the deformation and failure degree of surrounding rock gradually increases, and the overall failure and instability occur eventually. Compared with the static load, the range of critical spacing under dynamic disturbance is enlarged by 33.3%-50%. Meanwhile, the response of anchored surrounding rock is gradually intensified with the dynamic load strength increase, and the critical strength of failure and instability is about 4.0-4.5 MPa. Based on the elastic-plastic mechanics and elastic wave theories, the mechanical model of anchored surrounding rock under dynamic and static loads is established. The failure and instability criterion are obtained. The anchored surrounding rock can be divided into three states: overall stability, static failure and dynamic failure. On this basis, the analytical expression of critical distance between failure and instability is presented. Finally, in-site calculation and field monitoring verify the rationality and feasibility of the theoretical analysis. This study provides a reference for layout design and stability control of super-large section chamber group.

Objective: We aim to explore the capacity of perioperative pupillary variables to predict acute pain in the post‐anesthesia care unit (PACU). Methods: Patients scheduled to undergo thoracic or abdominal surgery under general anesthesia between April 2021 and June 2021 were enrolled. We measured the pupil diameter, pupillary light reflex (PLR), and pupillary reflex dilatation 5 min before anesthesia induction (T1), 5 min after intubation (T2), at the end of anesthesia (T3), immediately before extubation (T4), and 5 min after extubation (T5). We assessed the early postoperative pain intensity in the PACU using Numeric Rating Scales (NRS) at recovery, 5 min after recovery, and 10 min after recovery. Logistic regression models were used to evaluate the association between perioperative pupillary variables and postoperative pain intensity. Results: Fifty‐one patients were enrolled, 50 of whom were included in the final analysis. A total of 13 patients (26%) needed remedial analgesia in the PACU. Pupil parameters at T1, T2, T3, and T5 were not associated with NRS in the PACU. Multiple logistic regression models and receiver operating characteristic (ROC) curves indicated that only latency of PLR at T4 can predict postoperative acute pain. The ROC analysis showed that the cutoff value for latency of PLR at T4 was 0.29 s to discriminate between no pain and pain, and the area under the curve was 0.778 (95% CI 0.634–0.922, p = 0.002) with sensitivity 50.0% and specificity 91.7%. Conclusion: The latency of PLR immediately before extubation may be a useful predictor for postoperative acute pain in the PACU. [ABSTRACT FROM AUTHOR]

General anesthesia is widely applied in clinical practice. However, the precise mechanism of loss of consciousness induced by general anesthetics remains unknown. Here, we measured the dynamics of five neurotransmitters, including γ-aminobutyric acid, glutamate, norepinephrine, acetylcholine, and dopamine, in the medial prefrontal cortex and primary visual cortex of C57BL/6 mice through in vivo fiber photometry and genetically encoded neurotransmitter sensors under anesthesia to reveal the mechanism of general anesthesia from a neurotransmitter perspective. Results revealed that the concentrations of γ-aminobutyric acid, glutamate, norepinephrine, and acetylcholine increased in the cortex during propofol-induced loss of consciousness. Dopamine levels did not change following the hypnotic dose of propofol but increased significantly following surgical doses of propofol anesthesia. Notably, the concentrations of the five neurotransmitters generally decreased during sevoflurane-induced loss of consciousness. Furthermore, the neurotransmitter dynamic networks were not synchronized in the non-anesthesia groups but were highly synchronized in the anesthetic groups. These findings suggest that neurotransmitter dynamic network synchronization may cause anesthetic-induced loss of consciousness.