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Objective The main defects on metro tunnel inner wall are cracks and water seepage. Current detection methods based on manual and semi-automatic equipment have problems such as high intensity, low efficiency, and low reliability. The intelligence-based detection/identification algorithm and detection system should be studied to realize informative and intelligent detection for metro tunnel lining defects. Method The current status of metro tunnel defect inspection technology is analyzed, and a set of algorithms applicable to the identification of metro tunnel lining defects are put forward, mainly including image processing algorithm, defect category detection algorithm, and defect grading detection algorithm, etc. Four indexes are chosen to evaluate the detection effect of the identification algorithm. Furthermore, an intelligent detection system for metro tunnel lining defects based on deep learning method is established from both software and hardware aspects. Finally, the system is implemented on Beingjing Metro Line 3 to analyze the reliability of its on-site application. Result & Conclusion After the application of the intelligent detection system, the detection rate of metro tunnel lining crack defects reaches 91.95% with a false detection rate of 0.89%. The detection rate of seepage defect is 93.83% and the false detection rate 0.65%. This system can be used as the core intelligent detection platform of metro tunnel, effectively detecting various defects in metro tunnel.

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Infectious chronic wounds have gradually become a major clinical problem due to their high prevalence and poor treatment outcomes. The urgent need for wound dressings with immune modulatory, antibacterial, and angiogenic properties has led to the development of innovative solutions. Asiatic acid (AA), derived from herbs, has demonstrated excellent antibacterial, anti-inflammatory, and angiogenic effects, making it a promising candidate for incorporation into hydrogel carriers for wound healing. However, there is currently no available report on AA-based self-assembled hydrogels. Here, a novel hybrid hydrogel dressing consists of interpenetrating polymer networks composed of self-assembled magnesium ion (Mg 2+ ) coordinated asiatic acid (AA-Mg) and bacterial cellulose (BC) is developed to promote infected chronic wound healing. A natural carrier-free self-assembled AA-Mg hydrogel with good injectable and self-healing properties could maintain the sustained release of AA and Mg 2+ over an extended period. Notably, the introduction of Mg 2+ boosted some pharmacological effects of self-assembled hydrogels due to its excellent anti-inflammatory and angiogenesis. In vitro studies confirmed the exceptional biocompatibility, antibacterial efficacy, and anti-inflammatory potential of the AA-Mg/BC hybrid hydrogel, which also exhibited a commendable mechanical strength. Furthermore, in vivo biological results displayed that the hybrid hydrogel significantly accelerated the wound healing process by boosting dense and organized collagen deposition and the granulation tissue and benefiting revascularization. The introduced self-assembled AA-Mg-based hydrogel offers a promising solution for the effective management of chronic wounds. This universal strategy for the preparation of self-assembled hydrogels modulated with bioactive divalent metal ions is able to excavate more herbal small molecules to construct new self-assembled biomaterials.