In the present research, a microneedle Cu (II) selective electrode based on conducting polypyrrole (PPy) doped with 8-hydroxyquinoline-5-sulfonic acid (8-HQS) is introduced. 8-HQS which has been incorporated into the polypyrrole backbone during electropolymerization acts as an active ionophore for Cu (II) ion recognition. Several relevant factors affecting the sensor performance have been investigated and optimized. The proposed electrode showed a linear response over the concentration range of 1.0 × 10−5 to 1.0 × 10−1 M with a sub-Nernstian slope of 22 ± 1 mV per decade change in Cu (II) concentration. The response time of the electrode was less than 10 s and the proposed electrode revealed good selectivity for Cu (II) over a wide variety of other ions and could be used in the pH range of 4.0–7.0. The electrode was successfully employed as an indicator electrode in potentiometric titration of Cu (II) ion with EDTA and also for direct determination of copper in spiked tap water and fruit juice samples. The proposed electrode presents special features such as simplicity of operation, capability of miniaturization of steel substrate, low cost, simple fabrication and suitability to be used as Cu (II) disposable electrode and for mass production.
Introduction: Mortality is a key criterion for quality and safety in surgery. Studies show the higher rate of perioperative mortality in children compared with adults. The aim of present study was to determine the mortality rate after surgery among pediatric population. Methods: This retrospective study of perioperative mortality rate was performed in children younger than 18 years who operated at surgery unit of Dr. Sheikh pediatric tertiary hospital, Iran. Records of all cases of pediatric surgery performed under anesthesia between March 2015 and March 2018 were reviewed. Mortality rate at different time intervals after surgery, demographic characteristics and comorbidities of patients, type and duration of surgery, the number of operations in each child, the time interval between surgery and death, and the emergency level of surgery were recorded. Chi-square test was used for analysis of results. Results: Out of 5,5027 surgeries, 214 deaths were recorded, 78.6% of which occurred within one month after surgery. Mortality rate per 10,000 surgeries in the first year was about 49, which dropped to 10 in the third year. The mean value of mortality within 30-day post-surgery was 27.44 per 10000 procedures. The highest mortality rate was observed in people under 3 years of age with 67.2% and in females with 52.8%. Cardiac disease was at the top of comorbidities among dead patients. There was significant relationship between age and type of surgery with time interval between surgery and death. Conclusion: Infant age group and type of surgery was the main predictor of perioperative mortality.
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