Nonstoichiometric Oxides as Low-Cost and Highly-Efficient Oxygen Reduction/Evolution Catalysts for Low-Temperature Electrochemical Devices

The recent advances in the development of nonstoichiometric oxides, ranging from simple oxide, perovskite, layered perovskite, and pyrochlore, for oxygen reduction Reaction (ORR) and oxygen evolution reaction (OER) in metal-air batteries (MABs) and low-temperature fuel cells (LTFCs) are reviewed. These catalysts are characterized to be low cost and earth-abundant, as well as possess relatively high activity and stability under operation conditions. It is expected that these catalysts will be essential to the future development of multiple technologies. It is expected that the development of nonstoichiometric oxides, with the mutual development of system components, will lead to highly stable and efficient MABs and LTFCs in practical applications in the near future. The electrochemical strain microscopy technique may provide a direct visualization of the ORR/OER activation process on the scale of several nanometers and provide nanoscale understanding into local kinetics. An efficient approach to discover new materials with high intrinsic activities is to tune the electronic structure of existing materials

Quality of Life and Cognitive Function Evaluations and Interventions for Patients with Brain Metastases in the Radiation Oncology Clinic

Brain metastases (BMs) account for a disproportionately high percentage of cancer morbidity and mortality. Historically, studies have focused on improving survival outcomes, and recent radiation oncology clinical trials have incorporated HRQOL and cognitive assessments. We are now equipped with a battery of assessments in the radiation oncology clinic, but there is a lack of consensus regarding how to incorporate them in modern clinical practice. Herein, we present validated assessments for BM patients, current recommendations for future clinical studies, and treatment advances that have improved HRQOL and cognitive outcomes for BM patients

Compositional engineering of perovskite oxides for highly efficient oxygen reduction reactions

Mixed conducting perovskite oxides are promising catalysts for high-temperature oxygen reduction reaction. Pristine SrCoO3−δ is a widely used parent oxide for the development of highly active mixed conductors. Doping a small amount of redox-inactive cation into the B site (Co site) of SrCoO3−δ has been applied as an effective way to improve physicochemical properties and electrochemical performance. Most findings however are obtained only from experimental observations, and no universal guidelines have been proposed. In this article, combined experimental and theoretical studies are conducted to obtain fundamental understanding of the effect of B-site doping concentration with redox-inactive cation (Sc) on the properties and performance of the perovskite oxides. The phase structure, electronic conductivity, defect chemistry, oxygen reduction kinetics, oxygen ion transport, and electrochemical reactivity are experimentally characterized. In-depth analysis of doping level effect is also undertaken by first-principles calculations. Among the compositions, SrCo0.95Sc0.05O3−δ shows the best oxygen kinetics and corresponds to the minimum fraction of Sc for stabilization of the oxygen-vacancy-disordered structure. The results strongly support that B-site doping of SrCoO3−δ with a small amount of redox-inactive cation is an effective strategy toward the development of highly active mixed conducting perovskites for efficient solid oxide fuel cells and oxygen transport membranes