7 research outputs found
Removal and Reoccurrence of LLZTO Surface Contaminants under Glovebox Conditions
The reactivity of Li6.4La3Zr1.4Ta0.6O12 (LLZTO) solid electrolytes to form lithio-phobic species such as Li2CO3 on their surface when exposed to trace amounts of H2O and CO2 limits the progress of LLZTO-based solid-state batteries. Various treatments, such as annealing LLZTO within a glovebox or acid etching, aim at removing the surface contaminants, but a comprehensive understanding of the evolving LLZTO surface chemistry during and after these treatments is lacking. Here, glovebox-like H2O and CO2 conditions were recreated in a near ambient pressure X-ray photoelectron spectroscopy chamber to analyze the LLZTO surface under realistic conditions. We find that annealing LLZTO at 600 °C in this atmosphere effectively removes the surface contaminants, but a significant level of contamination reappears upon cooling down. In contrast, HCl(aq) acid etching demonstrates superior Li2CO3 removal and stable surface chemistry post treatment. To avoid air exposure during the acid treatment, an anhydrous HCl solution in diethyl ether was used directly within the glovebox. This novel acid etching strategy delivers the lowest lithium/LLZTO interfacial resistance and the highest critical current density
âItâs more than just a gameâ: NCCAA Division II student-athletesâ perceptions of coach caring
Plasma Vascular Endothelial Growth Factor Concentrations after Intravitreous AntiâVascular Endothelial Growth Factor Therapy for Diabetic Macular Edema
© 2018 American Academy of Ophthalmology Purpose: To assess systemic vascular endothelial growth factor (VEGF)-A levels after treatment with intravitreous aflibercept, bevacizumab, or ranibizumab. Design: Comparative-effectiveness trial with participants randomly assigned to 2 mg aflibercept, 1.25 mg bevacizumab, or 0.3 mg ranibizumab after a re-treatment algorithm. Participants: Participants with available plasma samples (N = 436). Methods: Plasma samples were collected before injections at baseline and 4-week, 52-week, and 104-week visits. In a preplanned secondary analysis, systemic-free VEGF levels from an enzyme-linked immunosorbent assay were compared across anti-VEGF agents and correlated with systemic side effects. Main Outcome Measures: Changes in the natural log (ln) of plasma VEGF levels. Results: Baseline free VEGF levels were similar across all 3 groups. At 4 weeks, mean ln(VEGF) changes were â0.30±0.61 pg/ml, â0.31±0.54 pg/ml, and â0.02±0.44 pg/ml for the aflibercept, bevacizumab, and ranibizumab groups, respectively. The adjusted differences between treatment groups (adjusted confidence interval [CI]; P value) were â0.01 (â0.12 to +0.10; P = 0.89), â0.31 (â0.44 to â0.18; P \u3c 0.001), and â0.30 (â0.43 to â0.18; P \u3c 0.001) for aflibercept-bevacizumab, aflibercept-ranibizumab, and bevacizumab-ranibizumab, respectively. At 52 weeks, a difference in mean VEGF changes between bevacizumab and ranibizumab persisted (â0.23 [â0.38 to â0.09]; P \u3c 0.001); the difference between aflibercept and ranibizumab was â0.12 (P = 0.07) and between aflibercept and bevacizumab was +0.11 (P = 0.07). Treatment group differences at 2 years were similar to 1 year. No apparent treatment differences were detected at 52 or 104 weeks in the cohort of participants not receiving injections within 1 or 2 months before plasma collection. Participants with (N = 9) and without (N = 251) a heart attack or stroke had VEGF levels that appeared similar. Conclusions: These data suggest that decreases in plasma free-VEGF levels are greater after treatment with aflibercept or bevacizumab compared with ranibizumab at 4 weeks. At 52 and 104 weeks, a greater decrease was observed in bevacizumab versus ranibizumab. Results from 2 subgroups of participants who did not receive injections within at least 1 month and 2 months before collection suggest similar changes in VEGF levels after stopping injections. It is unknown whether VEGF levels return to normal as the drug is cleared from the system or whether the presence of the drug affects the assay\u27s ability to accurately measure free VEGF. No significant associations between VEGF concentration and systemic factors were noted