Efficacy of Left Atrial Appendage Closure and Oral Anticoagulation After Atrial Fibrillation Catheter Ablation.

Left atrial appendage closure (LAAC) proved to be noninferior to oral anticoagulation (OAC) in nonablated patients with atrial fibrillation (AF). This study aimed to compare the efficacy and safety of LAAC with those of OAC therapy in patients after AF ablation. This study included patients who underwent catheter ablation (CA) of AF between January 2016 and December 2020. The cohort was divided into CA + LAAC and CA + OAC, where propensity score matching was used to select controls, and each group contained 682 subjects. The enrolled patients' mean age was 70.34 ± 8.32 years, and 47.3% were female; their CHA2DS2-VASc score was 3.48 ± 1.17. Baseline characteristics were similar between groups. After a 3-year mean follow-up, the incidence of thromboembolic events was 1.25 and 1.10 and that of major bleeding events was 0.65 and 1.72 per 100 patient-years in the CA + LAAC, and CA + OAC groups, respectively. The rate of thromboembolisms and major adverse cardiovascular events was similar between the 2 groups (hazard ratio [HR] 1.162, 95% confidence interval [CI] 0.665 to 2.030, p = 0.598, HR 0.711, 95% CI 0.502 to 1.005, p = 0.053); however, that of major bleeding and all-cause death was significantly reduced with LAAC (HR 0.401, 95% CI 0.216 to 0.746, p = 0.004, HR 0.528, 95% CI 0.281 to 0.989, p = 0.046). There was no significant difference in periprocedural complications (p >0.05) and the rate of AF recurrence (OAC vs LAAC: 39.44% vs 40.62%, p = 0.658). LAAC is a reasonable and safer alternative to OAC therapy in high-risk patients after AF ablation.

Enhancing the Thermoelectric and Mechanical Properties of Bi0.5Sb1.5Te3 Modulated by the Texture and Dense Dislocation Networks.

Bi2Te3-based materials are dominating thermoelectrics for almost all of the room-temperature applications. To meet the future demands, both their thermoelectric (TE) and mechanical properties need to be further improved, which are the requisite for efficient TE modules applied in areas such as reliable micro-cooling. The conventional zone melting (ZM) and powder metallurgy (PM) methods fall short in preparing Bi2Te3-based alloys, which have both a highly textured structure for high TE properties and a fine-grained microstructure for high mechanical properties. Herein, a mechanical exfoliation combined with spark plasma sintering (ME-SPS) method is developed to prepare Bi0.5Sb1.5Te3 with highly improved mechanical properties (correlated mainly to the dislocation networks), as well as significantly improved thermoelectric properties (correlated mainly to the texture structure). In the method, both the dislocation density and the orientation factor (F) can be tuned by the sintering pressure. At a sintering pressure of 20 MPa, an exceptional F of up to 0.8 is retained, leading to an excellent power factor of 4.8 mW m-1 K-2 that is much higher than that of the PM polycrystalline. Meanwhile, the method can readily induce high-density dislocations (up to ∼1010 cm-2), improving the mechanical properties and reducing the lattice thermal conductivity as compared to the ZM ingot. In the exfoliated and then sintered (20 MPa) sample, the figure-of-merit ZT = 1.2 (at 350 K), which has increased by about ∼20%, and the compressive strength has also increased by ∼20%, compared to those of the ZM ingot, respectively. These results demonstrate that the ME-SPS method is highly effective in preparing high-performance Bi2Te3-based alloys, which are critical for TE modules in commercial applications at near-room temperature.

Activate Fe3S4 Nanorods by Ni Doping for Efficient Dye-Sensitized Photocatalytic Hydrogen Production.

Developing suitable catalysts capable of receiving injected electrons and possessing active sites for hydrogen evolution reaction (HER) is the key to building an efficient dye-sensitized system for hydrogen production. Fe3S4 is generally regarded as an inferior HER catalyst among the metal sulfide family, mainly due to its weak surface adsorption toward H atoms. In this work, we demonstrate a facile metal-organic framework-derived method to synthesize uniform Fe3S4 nanorods and active them for HER by Ni doping. Our experimental results and theoretical calculations reveal that Ni doping can greatly modify the electronic structure of Fe3S4 nanorods, improving their electron conductivity and optimizing their surface adsorption energy toward H atoms. Sensitized by a commercial organic dye (eosin-Y), 1%Ni-doped Fe3S4 nanorods display a high H2 production rate of 3240 µmol gcat-1 h-1 with an apparent quantum yield of 12% under 500 nm wavelength, which is significantly higher than that of pristine Fe3S4 and even higher than that of 1% Pt-deposited Fe3S4. The working mechanism of this dye-sensitized system is explored, and the effect of Ni-doping concentration has been studied. This work presents a facile strategy to synthesize metal-doped sulfide nanocatalysts with greatly enhanced activity toward photocatalytic H2 production.

Vanadate-Rich BiOBr/Bi Nanosheets for Effective Adsorption and Visible-Light-Driven Photodegradation of Rhodamine B.

Two-dimensional (2D) BiOBr nanosheets (NSs) have attracted considerable interest as photocatalysts. The surface active sites of BiOBr NSs are crucial in determining the photocatalytic performance of these materials under visible light. The modification of the surface state of BiOBr NSs with multiple charged groups has been scarcely studied as a way to increase the number of surface active sites and the corresponding photocatalytic activity. Herein, vanadate-rich 2D BiOBr/Bi NSs were in-situ fabricated without adding strong reductants and subsequently used for visible-light-driven photocatalysis. Even under reductant-free condition, we were able to simultaneously deposit Bi0 and vanadate groups on the surface of pristine BiOBr NSs. The corresponding formation mechanism was also explored in a subsequent step. Compared to pristine BiOBr NSs and BiOBr/Bi NSs, the vanadate-rich BiOBr/Bi NSs prepared herein exhibited superior adsorption and enhanced photodegradation of Rhodamine B (RhB) under visible light illumination.

Low-Temperature Presynthesized Crystalline Tin Oxide for Efficient Flexible Perovskite Solar Cells and Modules.

Organic-inorganic metal halide perovskite solar cells (PSCs) have been emerging as one of the most promising next generation photovoltaic technologies with a breakthrough power conversion efficiency (PCE) over 22%. However, aiming for commercialization, it still encounters challenges for the large-scale module fabrication, especially for flexible devices which have attracted intensive attention recently. Low-temperature processed high-performance electron-transporting layers (ETLs) are still difficult. Herein, we present a facile low-temperature synthesis of crystalline SnO2 nanocrystals (NCs) as efficient ETLs for flexible PSCs including modules. Through thermal and UV-ozone treatments of the SnO2 ETLs, the electron transporting resistance of the ETLs and the charge recombination at the interface of ETL/perovskite were decreased. Thus, the hysteresis-free highly efficient rigid and flexible PSCs were obtained with PCEs of 19.20 and 16.47%, respectively. Finally, a 5 × 5 cm2 flexible PSC module with a PCE of 12.31% (12.22% for forward scan and 12.40% for reverse scan) was fabricated with the optimized perovskite/ETL interface. Thus, employing presynthesized SnO2 NCs to fabricate ETLs has showed promising for future manufacturing.

Thermoelectric properties of n-type ZrNiSn prepared by rapid non-equilibrium laser processing.

The traditional manufacturing of thermoelectric (TE) modules is a complex process that requires a long processing time and is high cost. In this work, we introduce a novel one-step 3D printing technique for TE module manufacturing, which integrates the Self-propagation High-temperature Synthesis (SHS) with the Selective Laser Melting (SLM) method. As a demonstration of this technique, bulk ZrNiSn samples were successfully fabricated on a Ti substrate. The effect of SLM processing parameters, such as the laser power and the scanning speed, on the quality of the forming ZrNiSn layers was systematically studied and analyzed, and the optimal processing window for the SLM process was determined. Transport property measurements indicate that the SLM-processed ZrNiSn possesses the maximum thermoelectric figure of merit ZT of 0.39 at 873 K. The interface of the ZrNiSn with the Ti substrate shows good adherence and low contact resistivity. The work demonstrates the viability of the SHS-SLM method for rapid fabrication of TE materials, legs and even modules.