Error Analysis of Normal Surface Measurements Based on Multiple Laser Displacement Sensors.

The robotic drilling of assembly holes is a crucial process in aerospace manufacturing, in which measuring the normal of the workpiece surface is a key step to guide the robot to the correct pose and guarantee the perpendicularity of the hole axis. Multiple laser displacement sensors can be used to satisfy the portable and in-site measurement requirements, but there is still a lack of accurate analysis and layout design. In this paper, a simplified parametric method is proposed for multi-sensor normal measurement devices with a symmetrical layout, using three parameters: the sensor number, the laser beam slant angle, and the laser spot distribution radius. A normal measurement error distribution simulation method considering the random sensor errors is proposed. The measurement error distribution laws at different sensor numbers, the laser beam slant angle, and the laser spot distribution radius are revealed as a pyramid-like region. The influential factors on normal measurement accuracy, such as sensor accuracy, quantity and installation position, are analyzed by a simulation and verified experimentally on a five-axis precision machine tool. The results show that increasing the laser beam slant angle and laser spot distribution radius significantly reduces the normal measurement errors. With the laser beam slant angle ≥15° and the laser spot distribution radius ≥19 mm, the normal measurement error falls below 0.05°, ensuring normal accuracy in robotic drilling.

A Visual Measurement Method for Deep Holes in Composite Material Aerospace Components.

The visual measurement of deep holes in composite material workpieces constitutes a critical step in the robotic assembly of aerospace components. The positioning accuracy of assembly holes significantly impacts the assembly quality of components. However, the complex texture of the composite material surface and mutual interference between the imaging of the inlet and outlet edges of deep holes significantly challenge hole detection. A visual measurement method for deep holes in composite materials based on the radial penalty Laplacian operator is proposed to address the issues by suppressing visual noise and enhancing the features of hole edges. Coupled with a novel inflection-point-removal algorithm, this approach enables the accurate detection of holes with a diameter of 10 mm and a depth of 50 mm in composite material components, achieving a measurement precision of 0.03 mm.

The influence of minimally invasive esophagectomy on wound infection in patients undergoing esophageal cancer surgery: A meta-analysis.

The impacts of minimally invasive esophagectomy (MIE) in comparison with open esophagectomy (OE) on postoperative complications, wound infections and hospital length of stay in patients with esophageal carcinoma (ESCA) using meta-analysis to provide reliable evidence for clinical practice. A search strategy was developed and computer searches were performed on Embase, Web of Science, PubMed, Cochrane Library, Wanfang, China Biomedical Literature Database and China National Knowledge Infrastructure databases for clinical studies that reported the effects of MIE in comparison with OE in patients with ESCA. The retrieval time was from their inception to October 2023. Two authors independently performed literature screening, and data extraction and literature quality evaluation were performed separately for the included studies. Meta-analysis was performed using Stata 17.0 software. Overall, 26 studies with 2427 ESCA patients were included in this study, of which 1203 were in the MIE group and 1224 were in the OE group. The results showed that, compared with OE, ESCA patients who underwent MIE were less likely to develop postoperative wound infections (odds ratio [OR] = 0.31, 95% confidence intervals [CIs]: 0.20-0.49, p < 0.001) and complications (OR = 0.23, 95% CI: 0.18-0.30, p < 0.001) and have a shorter hospital stay (standardized mean difference = -1.93, 95% CI: -2.38 to -1.48, p < 0.001). MIE has advantages over OE in terms of shorter hospital stay and reduced incidence of postoperative wound infections and complications.

Poor serum uric acid control increases risk for developing hypertension: a retrospective cohort study in China.

Background: Serum uric acid (SUA) has been suggested as a contributor of hypertension. However, reports on the relationship between changes in SUA and hypertension are limited. Hence, we aimed to investigate the potential impact of SUA, especially its change over time, on hypertension incidence. Methods: This dynamic cohort included 6052 participants without hypertension at baseline. Participants were categorized into six grades based on whether baseline SUA was high and whether changes in SUA progressed to hyperuricemia or decreased to normal levels. Grades 1 to 6 represented the participants' SUA control from best to worst. Logistic regression and restricted cubic spline (RCS) models were used to explore the association of the grades of SUA control and hypertension incidence. Results: During a median follow-up of 6 years, 2550 (42.1%) participants developed hypertension. After adjusting confounding factors, compared to grade 1 with the best control of SUA, the odds ratios for grades 2 to 6 with worse control were 1.347 (1.109-1.636), 1.138 (0.764-1.693), 1.552 (1.245-1.934), 1.765 (1.170-2.663), and 2.165 (1.566-2.993), respectively. RCS indicated a linear correlation between the risk of hypertension and changes in SUA, and an elevated risk in participants with baseline hyperuricemia. Subgroup analyses showed that grades of SUA control had an interaction with systolic (P = 0.003) and diastolic blood pressure (P < 0.001). Sensitivity analyses further determined the robustness of the result that participants with poor SUA control have a higher risk of developing hypertension. Conclusion: Poor SUA control, an increase in SUA over time, rises the risk of developing hypertension regardless of whether the initial SUA is normal or not. Initial hyperuricemia will exacerbate this risk. Effective SUA control should be an important measure for primary prevention of hypertension.