[Risk factors for delayed bleeding after intestinal polypectomy in children]. / å„¿ç«¥è‚ æ¯è‚‰åˆ‡é™¤æœ¯åŽè¿Ÿå‘æ€§å‡ºè¡€çš„å±é™©å› ç´ åˆ†æž.

OBJECTIVES: To investigate the clinical characteristics and risk factors of delayed bleeding after intestinal polypectomy in children, and to provide a theoretical basis for clinical surgical intervention of intestinal polyps. METHODS: A retrospective analysis was conducted on the clinical data of 2 456 children with intestinal polyps who underwent endoscopic high-frequency electrocoagulation loop resection in the Endoscopy Center of Children's Hospital Affiliated to Zhengzhou University from January 2014 to December 2021. According to the presence or absence of delayed bleeding after surgery, they were divided into bleeding group with 79 children and non-bleeding group with 2 377 children. A multivariate logistic regression analysis was used to investigate the risk factors for delayed bleeding. The receiver operating characteristic (ROC) curve was used to investigate the value of various indicators in predicting delayed bleeding. RESULTS: Of all 2 456 children, 79 (3.22%) experienced delayed bleeding, among whom 5 children with severe delayed bleeding underwent emergency colonoscopy for hemostasis and 74 received conservative treatment, and successful hemostasis was achieved for all children. There were significant differences between the bleeding and non-bleeding groups in age, body mass index, constipation rate, location of lesion, time of endoscopic procedure, resection method (P<0.05). Children with a diameter of polyps of 6-10 mm and >20 mm were more likely to develop delayed bleeding after resection (P<0.05). The multivariate logistic regression analysis showed that endoscopic operation time, polyp diameter, and resection method were significantly associated with delayed bleeding (P<0.05). The ROC curve analysis showed that the endoscopic operation time, polyp diameter, and resection method had a good value in predicting delayed bleeding after intestinal polypectomy, with an area under the ROC curve of 0.706, 0.688, and 0.627, respectively. CONCLUSIONS: Endoscopic high-frequency electrocoagulation loop resection has a lower incidence of delayed bleeding in children with intestinal polyps, and the endoscopic operation time, polyp diameter, and resection method are closely associated with the occurrence of postoperative delayed bleeding.

Dynamic Acoustic Beamshaping with Coupling-Immune Moiré Metasurfaces.

Moiré effects arising from mutually twisted metasurfaces have showcased remarkable wave manipulation capabilities, unveiling tantalizing emerging phenomena such as acoustic moiré flat bands and topological phase transitions. However, the pursuit of strong near-field coupling in layers has necessitated acoustic moiré metasurfaces to be tightly stacked at narrow distances in the subwavelength range. Here, moiré effects beyond near-field interlayer coupling in acoustics are reported and the concept of coupling-immune moiré metasurfaces is proposed. Remote acoustic moiré effects decoupled from the interlayer distance are theoretically, numerically, and experimentally demonstrated. Tunable out-of-plane acoustic beam scanning is successfully achieved by dynamically controlling twist angles. The engineered coupling-immune properties are further extended to multilayered acoustic moiré metasurfaces and manipulation of acoustic vortices. Good robustness against external disturbances is also observed for the fabricated coupling-immune acoustic moiré metasurfaces. The presented work unlocks the potential of twisted moiré devices for out-of-plane acoustic beam shaping, enabling practical applications in remote dynamic detection, and multiplexed underwater acoustic communication.