Electrochemical synthesis of H 2 O 2 through a selective two-electron (2e −) oxygen reduction reaction (ORR) is an attractive alternative to the industrial anthraquinone oxidation method, as it allows decentralized H 2 O 2 production. Herein, we report that the synergistic interaction between partially oxidized palladium (Pd δ+) and oxygen-functionalized carbon can promote 2e − ORR in acidic electrolytes. An electrocatalyst synthesized by solution deposition of amorphous Pd δ+ clusters (Pd 3 δ+ and Pd 4 δ+) onto mildly oxidized carbon nanotubes (Pd δ+-OCNT) shows nearly 100% selectivity toward H 2 O 2 and a positive shift of ORR onset potential by~320 mV compared with the OCNT substrate. A high mass activity (1.946 A mg −1 at 0.45 V) of Pd δ+-OCNT is achieved. Extended X-ray absorption fine structure characterization and density functional theory calculations suggest that the interaction between Pd clusters and the nearby oxygen-containing functional groups is key for the high selectivity and activity for 2e − ORR.

Aldehyde dehydrogenase 2 (ALDH2) is a mitochondrial enzyme that metabolizes ethanol and toxic aldehydes such as 4-hydroxy-2-nonenal (4-HNE). Using an unbiased proteomic search, we identified ALDH2 deficiency in stroke-prone spontaneously hypertensive rats (SHR-SP) as compared with spontaneously hypertensive rats (SHR). We concluded the causative role of ALDH2 deficiency in neuronal injury as overexpression or activation of ALDH2 conferred neuroprotection by clearing 4-HNE in in vitro studies. Further, ALDH2-knockdown rats revealed the absence of neuroprotective effects of PKCε. Moderate ethanol administration that is known to exert protection against stroke was shown to enhance the detoxification of 4-HNE, and to protect against ischemic cerebral injury through the PKCε-ALDH2 pathway. In SHR-SP, serum 4-HNE level was persistently elevated and correlated inversely with the lifespan. The role of 4-HNE in stroke in humans was also suggested by persistent elevation of its plasma levels for at least 6 months after stroke. Lastly, we observed that 21 of 1 242 subjects followed for 8 years who developed stroke had higher initial plasma 4-HNE levels than those who did not develop stroke. These findings suggest that activation of the ALDH2 pathway may serve as a useful index in the identification of stroke-prone subjects, and the ALDH2 pathway may be a potential target of therapeutic intervention in stroke.

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Objective. The objective of this study is to investigate the relationship between time in range (TIR), a new metric of continuous glucose monitoring (CGM) and cardiovascular autonomic neuropathy (CAN) in individuals with type 2 diabetes mellitus (T2DM). Methods. A total of 349 individuals with T2DM were enrolled in this study. Evaluating by the standard cardiac autonomic reflex tests (CARTs), there were 228 diabetic individuals without cardiovascular autonomic neuropathy (without confirmed CAN) including absent CAN (n=83 cases) and early CAN (n=145 cases) and 121 diabetic individuals complicated with cardiovascular autonomic neuropathy (CAN) including definite CAN (n=109 cases) and severe CAN (n=12 cases). All patients underwent 3-day CGM. TIR is defined as the time percent during a 24-hour period when the glucose is in the range of 3.9-10 mmol/L. The Spearman analysis was used to analyze the correlation between TIR and CART parameters, total CAN score. The logistic regression was applied to analyze the relationship between TIR and CAN by adjusting for the age, duration of diabetes, sex, lipid situation, serum creatinine, body mass index, blood pressure, HbA1c (%), and other glycemic variability (GV) metrics. Results. The total presence of CAN was 34.67% (definite CAN 31.23% and severe CAN 3.44%). Patients with more severe CAN had lower TIR (P<0.001). With increasing quartiles of TIR, the presence of CAN by severity declined (P<0.05). TIR is inversely correlated with total score of CAN (P<0.001) and positively associated with heart rate variation during the lying to standing, Valsalva maneuver, and deep breathing (P<0.05). The logistic regression found a robust association between TIR and CAN independent of HbA1c and GV metrics. Conclusion. TIR is associated with the presence of CAN independent of HbA1c and GV metrics in Chinese type 2 diabetes.