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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.

Cell-free circulating tumor DNA (ctDNA) is synthesized by tumor cells, including metastatic tumors, and circulates in the bloodstream. Evidence suggests that ctDNA is a potential predictive and prognostic biomarker for colorectal cancer (CRC), but its predictive efficacy in detecting CRC liver metastasis (CLM) remains unclear. Additionally, its utility in the clinical setting needs further investigation. We conducted a meta-analysis to determine the utility of ctDNA as a biomarker for predicting the prognosis of CLM and investigate the relationship between CLM and ctDNA positivity. A literature search was performed in electronic databases to identify relevant studies published up to March 19, 2022. We retrieved data on overall survival (OS), disease-free survival (DFS), and recurrence-free survival (RFS) for both ctDNA-positive and ctDNA-negative colorectal liver metastasis (CLM) patients from the selected articles. Hazard ratios (HRs) were also calculated for these survival outcomes analysis was also performed. The stability of the combined meta-analysis was verified by sensitivity analysis and publication bias evaluation. Ten trials were included, and 615 patients were evaluated. In patients with CLM, pooled HRs revealed a substantial link between ctDNA positivity and RFS/DFS. Subgroup analysis revealed that ctDNA had a prospective detection value. Sensitivity analysis and publication bias evaluation indicated stable results. Although the results on pooled HR for OS suggested that ctDNA-positive patients had a shorter survival time, their pooled HRs had a relatively evident heterogeneity, and sensitivity analysis and publication bias evaluation indicated that pooled HRs were extremely unstable. In conclusion, our results demonstrate that ctDNA appears to be a prognostic biomarker for resectable CLM patients.

This paper introduces a disinfection device for ICU nursing, which achieves the goal of integrated disinfection and drying of medical devices after use. During disinfection, the disinfectant can uniformly act on the surface of medical devices, drying quickly, and is conducive to use. (本研究介绍一种ICU护理用消毒装置, 能够达到医疗器械使用后消毒、烘干一体化效果, 且消毒时消毒液能够均匀作用于医疗器械表面, 干燥快速, 有利于提高消毒效率。)

Objectives In order to improve the safety performance of marine structures, fully nonlinear numerical simulation study is carried out on the problem of wave-structure interaction.Methods Based on the three-dimensional fully nonlinear time-domain potential flow theory and the higher-order boundary element method (HOBEM), an open water model for the interaction between waves and structures is established. The total velocity potential is decomposed into incident potential and scattering potential by the velocity potential separation technique. The mixed Euler-Lagrange (MEL) method is used to track the particle in the instantaneous free surface, and the fourth-order Runge-Kutta method is used to update the instantaneous free surface. In order to calculate wave loads, a virtual function is introduced instead of directly predicting the time derivative of the velocity potential. To prevent waves from reflecting from the far field boundary, an artificial damping layer is placed on the outside of the free surface. In addition, the free surface mesh is generated only once at the initial time, and then the spring approximation method is used to reconstruct the instantaneous free surface mesh without changing the order of mesh nodes, so as to avoid the possible numerical instability.Results On the basis of validating and verifying the present numerical model, a Floating Production, Storage and Offloading (FPSO) unit is numerically simulated to study its hydrodynamics. It is found that the motion response of FPSO increases obviously in the resonance section when considering the nonlinear effect, and it is proved that the prediction of the motion of FPSO by the traditional linear method is tend to be risk.Conclusions The work of this paper will provide a more reliable prediction tool for the design of the offshore floating structures and also provide the necessary theoretical basis for the practical application of the offshore floating structures.