CeO₂ Surface Oxygen Vacancy Concentration Governs in Situ Free Radical Scavenging Efficacy in Polymer Electrolytes

Nonstoichiometric CeO₂ and Ce_0.25Zr_0.75O₂ nanoparticles with varying surface concentrations of Ce³⁺ were synthesized. Their surface Ce³⁺ concentration was measured by XPS, and their surface oxygen vacancy concentrations and grain size were estimated using Raman spectroscopy. The surface oxygen vacancy concentration was found to correlate well with grain size and surface Ce³⁺ concentration. When incorporated into a Nafion polymer electrolyte membrane (PEM), the added nonstoichiometric ceria nanoparticles effectively scavenged PEM-degradation-inducing free radical reactive oxygen species (ROS) formed during fuel cell operation. A 3-fold increase in the surface oxygen vacancy concentration resulted in an order of magnitude enhancement in the efficacy of free radical ROS scavenging by the nanoparticles. Overall, the macroscopic PEM degradation mitigation rate was lowered by up to 2 orders of magnitude using nonstoichiometric ceria nanoparticles with high surface oxygen vacancy concentration

Table1_Post-event follow-up costs in patients with atherosclerotic cardiovascular disease in Spain.docx

IntroductionAtherosclerotic cardiovascular disease (ASCVD) is one of the main causes of morbidity and mortality in developed countries and entails high resources use and costs for health systems. The risk of suffering future cardiovascular (CV) events and the consequent resources use is higher in those patients who have already had a previous cardiovascular event. The objective of the study was to determine the average annual cost of patients with a new or recurrent atherosclerotic CV event during the 2 years after the event.MethodologyRetrospective observational study of electronic medical records of patients from the BIG-PAC® database (7 integrated health areas of 7 Autonomous Communities; n = 1.8 million). Patients with a new or recurrent episode of ASCVD (angina, acute myocardial infarction, transient ischemic attack, stroke, or peripheral arterial disease) between 1-Jan-2017 and 31-Dec-2018 were included. The resources use within two years of the diagnosis was estimated in order to estimate the average cost of patient follow-up.ResultsA total of 26,976 patients with an ASCVD episode were identified during the recruitment period; Out of them, 6,798 had a recurrent event during the follow-up period and 2,414 died. The average costs per patient were €11,171 during the first year and €9,944 during the second year.DiscussionPatients with ASCVD represent a significant economic burden for the health system and for society. Despite the perception that drug costs in the follow-up of chronic patients imply a high percentage of the costs, these accounted for only one tenth of the total amount. Implementing preventive programs and increasing the control of cardiovascular risk factors may have a significant social and health impact by helping to reduce mortality and costs for the Spanish National Health System. The costs derived from pharmacological treatments were obtained from the NHS pricing nomenclator database (https://www.sanidad.gob.es/profesionales/nomenclator.do).</p