Bivalirudin versus Heparin on Net Adverse Clinical Events, Major Adverse Cardiac and Cerebral Events, and Bleeding in Elderly Chinese Patients Treated with Percutaneous Coronary Intervention.

Bivalirudin as an anticoagulant reduces bleeding after percutaneous coronary intervention (PCI), while its impact in elderly Chinese patients treated with PCI needs more evidence. This study aimed to compare the clinical outcomes between bivalirudin and heparin in elderly Chinese patients treated with PCI. This cohort study retrieved data of 1,286 elderly patients treated with PCI who used bivalirudin (bivalirudin group, N = 493) or heparin (heparin group, N = 793) as anticoagulants. Net adverse clinical events (NACEs) (primary endpoint), major adverse cardiac and cerebral events (MACCEs), bleeding, and major bleeding within 30 days after PCI treatment were recorded for analysis. Our study illustrated that NACEs (12.4% vs. 17.4%, P = 0.015), bleeding (6.7% vs. 12.1%, P = 0.002), and major bleeding (2.2% vs. 6.6%, P < 0.001) were fewer in bivalirudin group compared to heparin group. No difference was found in MACCEs (7.5% vs. 9.6%,P = 0.200), and incidences of all-cause mortality (P = 0.257), cardiac mortality (P = 0.504), recurrent myocardial infarction (P = 0.423), ischemia-driven revascularization (P = 0.509), and stroke (P = 0.467), between bivalirudin group and heparin group. According to univariate logistic regression analyses, bivalirudin (vs. heparin) correlated with fewer NACEs (P = 0.016), bleeding (P = 0.002), and major bleeding (P = 0.001) in elderly patients treated with PCI, but not MACCEs (P = 0.202). After adjustment, bivalirudin (vs. heparin) was an independent factor for fewer NACEs [odds ratio (OR): 0.619, P = 0.009], bleeding (OR: 0.499, P = 0.003), and major bleeding (OR: 0.342, P = 0.003) in these patients. In summary, bivalirudin achieves fewer NACEs, bleeding, and major bleeding, but not MACCEs, versus heparin in elderly patients treated with PCI, which is verified in the multivariate model.

Electrochemical Preparation of Crystalline Hydrous Iridium Oxide and Its Use in Oxygen Evolution Catalysis.

Even the most stable Ir-based oxides inevitably encounter a severe degradation problem during the oxygen evolution reaction (OER) in acid, resulting in quick formation of amorphous IrOx layers on the catalyst surface. Unfortunately, there is still a lack of fundamental understanding of such hydrous IrOx layers, including the atomic arrangement, key active structure, compositions, chemical stability, and so on. In this work, we demonstrate an electrochemical strategy to prepare two types of protonated iridium oxides with well-defined crystalline structures: one possesses a 2D layered structure (denoted as α-HxIrO3) and the other consists of 3D interconnected polymorphs (denoted as ß-HxIrO3). Both protonated iridium oxides demonstrate superior electrochemical stabilities with 6 times suppressed Ir dissolution comparing to the initial Li2IrO3 and rutile IrO2. It is hypothesized that the enriched protons and fast diffusions in these two protonated HxIrO3 crystal oxides may promote surface structural stability by suppressing the formation of high-valence Ir species at the solid-liquid interfaces during OER. Overall, the results of this work shed light on the role of proton dynamics toward the OER processes on the catalyst surface in acid media.

Rational Design of Silicon Nanodots/Carbon Anodes by Partial Oxidization Strategy with High-Performance Lithium-Ion Storage.

Silicon (Si) is considered a promising anode material for rechargeable lithium-ion batteries (LIBs) due to its high theoretical capacity, low working potential, and safety features. However, the practical use of Si-based anodes is hampered by their huge volume expansion during the process of lithiation/delithiation, and they have relatively low intrinsic electronic conductivity, therefore seriously restricting their application in energy storage. Here, we propose a facile approach to directly transform siliceous biomass (bamboo leaves) into a porous carbon skeleton-wrapped Si nanodot architecture through a partial oxidization strategy and magnesium thermal reaction to obtain a high Si nanodot component composite (denoted as Si/C-O). With the synergistic effect of the porous carbon skeleton structure and uniformly dispersed Si nanodots, the Si/C-O composite anode with a stable structure that can avoid pulverization and accommodate volume expansion during cycling is fabricated. As expected, the biomass-converted Si/C-O anode not only presents a high Si component (59.7 wt %) by TGA but also exhibits an excellent capacity of 1013 mAh g-1 at 0.5 A g-1 and robust cycling stability with a capacity retention of 526 mAh g-1 after 650 cycles. Moreover, the Si/C-O anode demonstrates considerable performance in practical LIBs when assembled with a commercial LiNi0.8Co0.1Mn0.1O2 cathode. This work provides an effective strategy and long-term insights into the utilization of porous Si-based materials converted by biomass to design and synthesize high-performance LIB materials.

Investigation on a high gravity device for reduction of NOx emission from marine diesel engines.

High gravity technology, as a process intensification technology, has demonstrated the great advantages in the field of gas purification on account of its excellent mass transfer efficiency and energy-efficient, but it is rarely applied in the field of nitrogen oxides (NOx) purification of marine diesel engine exhaust. In this paper, a high-gravity bowl-shaped-disk rotating bed (HBRB) without catalytic was designed for diesel exhaust after-treatment. A diesel oxidation catalyst (DOC) was installed in the front of the HBRB to regenerate more nitrogen dioxide (NO2) easily reduced by urea. A bench test of a 6-cylinder marine diesel engine with the HBRB was carried out. The effects of the HBRB speeds, urea concentrations, and engine operating conditions on NOx purification efficiency in engine exhaust were experimentally investigated. The experimental result indicates that the maximum NOx removal efficiency of the HBRB can reach 69.1%. The improvement of the NOx removal efficiency is not obvious at the HBRB speed of over 1500 r/min. The pre-oxidation degree of nitric oxide (NO) and urea concentration largely affect the NOx removal efficiency. The HBRB has great potential in marine diesel engine exhaust denitration.

Investigation of the electrocatalytic mechanisms of urea oxidation reaction on the surface of transition metal oxides.

Urea oxidation reaction (UOR) has been widely considered as an alternative anodic reaction to water oxidation for the green production of hydrogen fuel. Due to the high catalytic activity of transition metal oxides towards UOR, various strategies have been developed to improve their syntheses and catalytic properties. However, little is known about the underlying mechanisms of UOR on catalyst surface. In this work, three transition metal oxides, including NiO, Co3O4, and Fe2O3 are investigated as model catalysts. Through analyzing the electrochemical properties by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and operando Raman spectroscopy, it is revealed that NiO has a unique high catalytic activity towards UOR due to simultaneous formation of a thin layer of oxyhydroxide species above 1.40 V vs. RHE in alkaline media. In addition, density functional theory (DFT) calculations further suggest that the adsorption of urea molecules is largely affected by surface interactions resulting in different space configurations, which impose large influences on the consecutive deprotonation and NN formation processes. Overall, results of this work point to the subtle adsorption - kinetics relationship in UOR and highlight the importance of the interfacial electronic interactions on catalyst surface.

Unveiling the promotion of intermediates transport kinetics on the N/S co-doping 3D structure titanium carbide aerogel for high-performance supercapacitors.

Two-dimensional (2D) transition metal carbides (MXene) have shown great advantages as electrode materials in the new generation of energy storage, especially in supercapacitors. However, the inherent low specific capacitance and restacking layers of nanosheets that occur during electrode preparation further reduce the electrochemical performance of the materials. Based on this, we design a N, S co-doping electrode with a three-dimensional (3D) structure, which not only improves the specific capacitance through fundamentally modifying the electronic structure of the electrode materials, but also effectively improves the rate performance of the electrode by preventing the restacking of 2D materials. The N, S co-doping 3D architecture Ti3C2Tx electrode (TC/NS-3D) exhibits an excellent capacitance value of 440 F g-1 at 5 mV s-1 and 64% capacitance retention rate at a high scan rate of 1000 mV s-1 in 3 mol L-1 H2SO4 electrolyte. The TC/NS-3D electrode also shows excellent capacitance retention of 97.2% after the 10,000 cycles stability test. The density functional theory (DFT) analysis reveals the enhanced performance is attributed to accelerated intermediates transport kinetics promoted by 3D structure engineering and N, S co-doping for Ti3C2Tx. This study is promising in designing heteroatomic doping 3D structure MXene-based materials for electrochemical energy storage systems.

Theoretical prediction of HfB2 monolayer, a two-dimensional Dirac cone material with remarkable Fermi velocity.

Searching for new two-dimensional (2D) Dirac cone materials has been popular since the discovery of graphene with a Dirac cone structure. Based on density functional theory (DFT) calculations, we theoretically designed a HfB2 monolayer as a new 2D Dirac material by introducing the transition metal Hf into a graphene-like boron framework. This newly predicted HfB2 monolayer has pronounced thermal and kinetic stabilities along with a Dirac cone with a massless Dirac fermion and Fermi velocities (3.59 × 105 and 6.15 × 105 m s-1) comparable to that of graphene (8.2 × 105 m s-1). This study enriches the diversity and promotes the application of 2D Dirac cone materials.

Functional Group Effects on the Photoelectronic Properties of MXene (Sc2CT2, T = O, F, OH) and Their Possible Photocatalytic Activities.

In view of the diverse functional groups left on the MXene during the etching process, we computationally investigated the effects of surface-group types on the structural, electronic and optical properties of Sc2CT2 (T = -O, -OH, -F) MXenes. For all geometries of the Sc2CT2 MXenes, the geometry I of Sc2CT2, which has the functional groups locating above the opposite-side Sc atoms, are lowest-energy structure. Accordingly, the energetically favorable Sc2CF2-I, Sc2CO2-I and Sc2C(OH)2-I were selected for further evaluation of the photocatalytic activities. We found that the Sc2CO2-I is metallic, while Sc2CF2-I and Sc2C(OH)2 are semiconductors with visible-light absorptions and promising carrier mobilities. Compared with the Sc2C(OH)2-I, the Sc2CF2-I has not only more suitable band gap (1.91 eV), but also the higher redox capability of photo-activated carriers, which should have better photocatalytic performance.