Objective To establish a method for the determination of organochlorine and organophosphorus pesticides residues in vegetables.Methods The heavy-caliber capillary gas chromatography and the program control temperature were used to separate and determine the residuals of the pesticides.Results As for the organophosphorus pesticides, the detection limits were 0.004-0.008 mg/kg;The linear range was 0.5-5.0 ?g/ml;The correlation coefficients were 0.996 5-0.999 0;The rates of recovery were 88.47%-96.51%;Relative standard deviations were 2.98%-5.16% .As for the organochlorine pesticides, the detection limits were 0.0007-0.001 mg/kg;The linear range was 0.002-0.2 ?g/ml;The correlation coefficients were 0.999 4-0.9997;The rates of recovery were 86.51%-98.45%;Relative standard deviations were 2.47%-5.32%.Conclusion This method may efficiently separate and determine the organochlorine and organophosphorus pesticides residues in vegetables with good sensibility and accuracy.

Objective:To evaluate the strategy and safety of the radiofrequency ablation (RFA) on ventricular arrhythmias (VAs) originating from the pulmonary sinus cusp (PSC) in pediatric patients.Methods:Retrospective study.Fifteen patients with VAs originating from the PSC who were intervened by RFA in the Department of Pediatric Cardiology, Guangdong Provincial People′s Hospital between March 2014 to July 2020 were enrolled.All the patients met the indication criteria for RFA in pediatric patients.The electrocardiogram, ablation method of ablation were analyzed.Different curved catheters were selected for RFA according to the age and weight of the patients.The catheter was then inserted in a " U" or inverted " P" shape to the PSC.The long-term effect of ablation were reviewed.Results:The mean age and body weight of 15 patients with VAs originating from the PSC were (11.6±2.6) (6-15) years and (39.9±12.2) (19-65) kg, respectively.The electrocardiogram recorded during VAs originating from the PSC showed left bundle branch block and inferior axis with monomorphic R pattern, as well as a QS-wave in aVR and aVL.The electrocardiogram characteristics varied in patients with VAs originating from the PSC.The ideal excitation point was not found in the right ventricular outflow tract or the ablation was unsuccessful in all patients, and the earliest target was mapped and RFA was successful.Among the 15 patients, the successful ablation site was in the lower regions of the PSC, involving the right cusp in 11 patients(73.3%), the anterior cusp in 3 patients(20.0%), and the left cusp in 1 patient(6.7%). The earliest potential recorded at the PSC ablation site preceded the QRS complex onset by (27.3±6.0) ms.During the follow-up period for (2.7±2.0) years, no recurrence of VAs or complications were recorded.Conclusions:Under the premise of gentle catheterization procedure and appropriate radiofrequency energy, ablation was effective, safe and with low recurrence rate to eradicate VAs originating from the PSC in children.