BackgroundShivering is a very common complication in the postanesthesia period. Increasing studies have reported ondansetron may be effective in prevention of postanesthesia shivering (PAS). However, the results remained controversial; hence we conducted a meta-analysis of randomized controlled trials to evaluate the efficacy and safety of ondansetron on the prevention of postanesthesia shivering.MethodsPubMed and Embase databases were searched to identify the eligible randomized controlled trials assessing the effect of ondansetron on the prevention of PAS. Results were expressed as risk ratios (RRs) with accompanying 95% confidence intervals (CIs). The meta-analysis was performed with fixed-effect model or random-effect model according to the heterogeneity.ResultsSix trials including 533 subjects were included. Compared with placebo, ondansetron was associated with a significant reduction of PAS (RR 0.43, 95% CI, 0.27-0.70), without an increased risk of bradycardia (RR 0.37, 95% CI, 0.12-1.15). Compared with meperidine, no difference was observed in the incidence of PAS (RR 0.68, 95% CI, 0.39-1.19) and bradycardia (RR 2.0, 95% CI, 0.38-10.64).ConclusionsOndansetron has a preventive effect on PAS without a paralleled side effect of bradycardia.

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Purpose As the development of smaller accelerators technique, an X-band bi-period side-coupled accelerating structure has been designed for medical use. Methods The structure's working frequency is 9.3 GHz. π/2 mode is chosen for the structure's stability. There are 11 accelerating cells and 10 coupling cells, the first 5 of the accelerating cells work as non-light velocity part (β of the electron from 0.17 to 0.94), while the other 6 work as light velocity part. After CST simulation, the coupling constant between accelerating cells and coupling cells is 5%, and efficient shunt impedance is 142 M /m. To feed power into the structure, a coupler is designed in the middle of the structure and the coupling coefficient is 1.4. Results After optimization, the particle's capture efficiency is more than 30%, the particle energy is 2 MeV and the peak current is 60 mA, with the magnetron's input power being 0.32 MW. Conclusion X-band side-coupled accelerator efficiency is high and is a more optimized design. This design is very meaningful for the development of smaller accelerators technique.

Purpose A 325-MHz bi-periodic on-axis coupled accelerating structure prototype which consists of two bi-periodic accelerating modules is under fabrication in the Institute of High Energy Physics, Beijing, dedicated to a 10-MeV/100 kW industrial linear electron accelerator. According to the beam dynamics study, the average power dissipated in the prototype cavity is about 19.1 kW. Effective cooling scheme is one of the most important issues in the high-power operation. Methods This paper mainly deals with the RF, thermal and structural coupled analyses of the accelerating structure prototype with the help of the ANSYS code. The cooling scheme is optimized to minimize the temperature rise, displacement and von Mises stresses. Results The temperature and stress distributions in the steady state are presented. The maximum von Mises stress is much lower than the yield strength limit of the corresponding material. The frequency shift caused by the thermal expansion is calculated as well, which is within the scope of the tuning range. Conclusion The coupled analyses based on the ANSYS software package are presented to design and optimize the cooling scheme of the accelerating structure. The von Mises stresses are much lower than the yield strength limit of the