A novel amphiprotic side-chain-functionalized membrane was for the first time designed for vanadium redox flow battery (VFB). Different from frequently used blending amphiprotic membranes, the one proposed here is allowed to possess high anion-exchange capacity (IEC) without sacrificing the cation-exchange capacity (IEC) because both IEC and IEC increased with the grafting degree of side chains. Having a high IEC, the membrane prepared here exhibits an ultralow vanadium permeability (<10 cm s), which leads to very high Coulombic efficiencies (97-98% at 40-200 mA cm) of VFB and good cell self-discharge durability. Moreover, the high IEC contributes to a decent ionic conductivity (area resistance: 0.5 Ω cm), which ensures a high-voltage efficiency of the cell. On the basis of these good properties, the VFB single cell with this membrane achieves a high energy efficiency (e.g., 77.4% at 200 mA cm) that is higher than those of Nafion 212 and other reported amphiprotic membranes. These results indicate that the approach proposed here is an ideal option to prepare amphiprotic membranes for VFBs with high efficiency and good durability.

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Objectives: This study aimed to identify variables and develop a prediction model that could estimate extubation failure (EF) in preterm infants.Study Design: We enrolled 128 neonates as a training cohort and 58 neonates as a validation cohort. They were born between 2015 and 2020, had a gestational age between 250/7 and 296/7 weeks, and had been treated with mechanical ventilation through endotracheal intubation (MVEI) because of acute respiratory distress syndrome. In the training cohort, we performed univariate logistic regression analysis along with stepwise discriminant analysis to identify EF predictors. A monogram based on five predictors was built. The concordance index and calibration plot were used to assess the efficiency of the nomogram in the training and validation cohorts.Results: The results of this study identified a 5-min Apgar score, early-onset sepsis, hemoglobin before extubation, pH before extubation, and caffeine administration as independent risk factors that could be combined for accurate prediction of EF. The EF nomogram was created using these five predictors. The area under the receiver operator characteristic curve was 0.824 (95% confidence interval 0.748–0.900). The concordance index in the training and validation cohorts was 0.824 and 0.797, respectively. The calibration plots showed high coherence between the predicted probability of EF and actual observation.Conclusions: This EF nomogram was a useful model for the precise prediction of EF risk in preterm infants who were between 250/7 and 296/7 weeks' gestational age and treated with MVEI because of acute respiratory distress syndrome.