Resilient Growth of a Highly Crystalline Topological Insulator-Superconductor Heterostructure Enabled by an Ex Situ Nitride Film.

Highly crystalline and easily feasible topological insulator-superconductor (TI-SC) heterostructures are crucial for the development of practical topological qubit devices. The optimal superconducting layer for TI-SC heterostructures should be highly resilient against external contamination and structurally compatible with TIs. In this study, we provide a solution to this challenge by showcasing the growth of a highly crystalline TI-SC heterostructure using refractory TiN (111) as the superconducting layer. This approach can eliminate the need for in situ cleavage or growth. More importantly, the TiN surface shows high resilience against contaminations during air exposure, as demonstrated by the successful recyclable growth of Bi2Se3. Our findings indicate that TI-SC heterostructures based on nitride films are compatible with device fabrication techniques, paving the way to the realization of practical topological qubit devices in the future.

Assessment of left ventricular structure and function in preeclampsia subtypes by multimodal echocardiography.

AIM: To explore left ventricular structural/functional abnormalities in preeclampsia patients by using multimodal echocardiography and to analyze the cardiac impact in preeclampsia subtypes. METHODS: A total of 103 individuals, including 64 preeclampsia patients and 39 healthy pregnant women were recruited for this study from 2019 to 2021. There were 34 patients with preeclampsia with severe features (SPE) patients and 30 with preeclampsia with nonsevere features (NSPE), including 9 with early-onset NSPE (EO-NSPE) patients, 27 early-onset SPE (EO-SPE) patients, 21 later-onset NSPE (LO-NSPE), and 7 with later-onset SPE (LO-SPE). All patients underwent multimodal echocardiography before treatment, including two-dimensional, Doppler, and speckle-tracking echocardiography, to evaluate left ventricular structure/function. Analysis of variance was used to determine statistical significance across groups. RESULTS: EO-SPE patients showed decreased left ventricular ejection fractions, peak longitudinal systolic strain at apical four-chambers, peak circumferential, and radial systolic strain at the apical and mitral annular plane systolic excursion (MAPSE), and increased mitral regurgitation compared to other preeclampsia patients. Compared to LO-NSPE and EO-SPE patients, LO-SPE patients showed increased left ventricular mass indexed to height2.7 and early diastolic left ventricular diastolic filling/mitral annular velocity, and decreased MAPSE and early/late diastolic mitral annular velocity. CONCLUSION: EO-SPE patients were characterized by left ventricular injury and systolic function reduced. LO-SPE patients were characterized by left ventricular hypertrophy and reduced diastolic function. Multimodal echocardiography can detect myocardial injury in PE patients at an early stage.

Tunable pH-dependent oxygen evolution activity of strontium cobaltite thin films for electrochemical water splitting.

Understanding the oxygen evolution reaction (OER) dependence on the reaction environment pH is important to find alternative strategies to define an optimal pH value for high electrocatalytic activity. SrCoO2.5 films with the brownmillerite phase are investigated in this study for their strain effects on the OER activity, with particular regard to the pH dependence. Pulsed laser deposited films with different thicknesses and, thus, strain conditions, are characterized in terms of long range and near-order structural properties and electrochemical OER activity. By comparison, more strained thinner films have smaller OER current at lower pH conditions, but higher sensitivity to the environment pH. Spectroscopic measurements allow us to correlate such behaviors to the Co 3d-O 2p hybridization effects of the CoO6 octahedral sites, which lead to a variation of the 3d level electronic occupation. At the same time, density functional theory calculations show that the oxygen vacancy channels of the CoO4 tetrahedral sites are stable with respect to the strain effects. These results provide new perspectives to manipulate the pH dependent OER activity through the strain effects, useful for designing water splitting-based devices with optimized performances.

The coupling of hemin with persistent free radicals induces a nonradical mechanism for oxidation of pollutants.

Herein, we report that persistent free radicals (PFRs) based on MWCNTs significantly accelerate the pollutant removal rate. EPR measurement combined with the electrochemical test indicated that a nonradical mechanism was responsible for the enhancement, which is different from the previously reported radical pathway on PFRs.