Objective To deduce analytic solution of the displacement and stress distributions for the coronary stent based on reasonable assumptions, and to investigate the influence from the wave number of support bars on stress distributions by combining the results of finite element analysis. Methods A local cylindrical coordinate system was established to deduce analytical solution of the displacement and stress components of the periodic support bar of the rectangular-wave type vascular stent under vascular systolic pressure. The support bar model was established by using ANSYS, to calculate the numerical results of stress analysis. By analyzing the consistency of stress curves obtained from the two methods, the accuracy and applicability of analytical solutions were verified. The influence from the number of wave crests for support bars on the stress under systolic pressure was investigated by analytic solution. Results The analytical stress curves were basically in conformity with those from the ANSYS results. When the number of wave crests was 6, there were both tensile and compressive stresses in circumferential direction of the cross bar. Conclusions When the number of wave crests was 6, such stents could effectively prevent restenosis in blood vessels during working. The derived analytical solution could be used to analyze mechanical properties of one-cycle support bars of rectangular-wave type stent, and the research findings provided a new idea to further recognize and study the stress distributions on coronary stent to reduce the restenosis rate of interventional therapy.

Objective:To evaluate the clinical characteristics and prognosis of febrile convulsions (FS) in children during the epidemic period of novel coronavirus Omicron variant.Methods:A retrospective analysis was conducted on the clinical data of pediatric patients diagnosed with FS at Changsha Central Hospital Affiliated to University of South China from February 1, 2022 to January 31, 2023. The clinical characteristics and prognosis of FS patients caused by Omicron variant infection (observation group) were compared with those caused by non Omicron variant infection (control group).Results:A total of 131 cases in the observation group and 341 cases in the control group; The proportion of children aged 12-36 months in the observation group was lower than that in the control group ( P<0.05), and the proportion of children aged ≥60 months was higher than that in the control group ( P<0.05). Most of the FS in the observation group occurred within 24 hours of fever (128/131, 97.7%), with a statistically significant difference compared to the control group ( P<0.05), and most of them were generalized tonic clonic seizures (127/131, 96.9%), with only one seizure during the course of the disease (114/131, 87.0%), consistent with the characteristics of simple FS. The main clinical symptoms of FS patients in the observation group were upper respiratory tract infections (108/131, 82.5%), which were significantly higher than those in the control group (164/341, 48.1%), while the incidence of lower respiratory tract infections was lower than that in the control group ( P<0.05). 369 pediatric patients were followed up by phone or outpatient visits, with 98 cases in the observation group and 2 cases experiencing recurrence. There was no recurrence in the group aged ≥60 months; A total of 271 cases were followed up in the control group, with 9 cases experiencing recurrence. Conclusions:The number of children with FS caused by novel coronavirus Omicron variant has increased sharply, and the proportion of late onset FS patients has increased significantly. Most of them are upper respiratory tract infections. Convulsions usually occur within 24 hours of fever, and the prognosis is good.