Partially fluorinated poly(arylene-alkane)s containing cobaltocenium for alkaline-stable anion exchange membranes.

Alkali-resistant metal-based cationic polyelectrolytes are designed as anion exchange membranes. After grafting aminocobaltocene hexafluorophosphates onto partially fluorinated ether-free poly(arylene-alkane)s via a simple nucleophilic substitution reaction, the membrane exhibits excellent chemical, thermal and mechanical stability, high hydroxide conductivity, as well as durability of single cells for 400 h.

Surface-Modified Approach to Fabricate Nafion Membranes Covalently Bonded with Polyhedral Oligosilsesquioxane for Vanadium Redox Flow Batteries.

An aminopropyl isobutyl polyhedral oligosilsesquioxane (NH2-POSS) surface-modified Nafion membrane has been designed by chemical grafting for vanadium redox flow batteries (VRFBs). NH2-POSS is a cage-like macromer consisting of an inorganic Si8O12 core surrounded by seven inert isobutyl groups and one active aminopropyl group. The sulfonic acid groups on the surface of Nafion can be activated by 1,1-carbonyldiimidazole for further modification with NH2-POSS. Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) prove that NH2-POSS has been successfully grafted on the surface of a Nafion 115 membrane. Although the proton conductivity decreases slightly, the organic-inorganic hybrid membranes display enhanced ion selectivity and excellent dimensional stability with lower water uptake and swelling ratio than Nafion 115. Moreover, two-dimensional-grazing incidence X-ray diffraction (2D-GIXRD) reveals that the introduction of NH2-POSS forms a POSS layer on the surface of the membrane and narrows the space of Nafion clusters, which helps to block VO2+ permeation. A VRFB with the surface-modified Nafion membrane displays an outstanding performance with an average Coulombic efficiency (CE) of 98.7% and energy efficiency (EE) of 84.5% at a current density of 80 mA cm-2, superior to those of the Nafion 115 membrane (CE = 95.7%, EE = 81.7%). Furthermore, the cell holds a high capacity retention of 49.2% after 1000 charge-discharge cycles, in contrast to that of 41.9% for the cell with Nafion 115 after only 200 cycles. The results suggest that the surface-modified hybrid membrane is a promising strategy to overcome the vanadium ion crossover in VRFBs.

Elevated serum FGF21 predicts the major adverse cardiovascular events in STEMI patients after emergency percutaneous coronary intervention.

BACKGROUND: Although there have been several studies related to serum fibroblast growth factor 21 (FGF21) levels and acute myocardial infarction, the value of serum FGF21 levels in ST-segment elevation myocardial infarction (STEMI) patients after emergency percutaneous coronary intervention (PCI) has not been previously investigated. METHODS: A total of 348 STEMI patients who underwent emergency PCI were enrolled from January 2016 to December 2018. The primary endpoint was the occurrence of major adverse cardiovascular events (MACEs), with a median follow-up of 24 months. Eighty patients with stable angina (SA) who underwent selective PCI served as the control group. Serum FGF21 levels were measured by ELISA. RESULTS: Serum FGF21 levels were significantly higher in the STEMI group than in the SA group (225.03 ± 37.98 vs. 135.51 ±  34.48, P < 0.001). Multiple linear regression analysis revealed that serum FGF21 levels were correlated with NT-proBNP (P < 0.001). According to receiver operating characteristic (ROC) analysis, the areas under the ROC curve (AUCs) of FGF21 and NT-proBNP were 0.812 and 0.865, respectively. The Kaplan-Meier curves showed that STEMI patients with lower FGF21 levels had an increased MACE-free survival rate. Cox analysis revealed that high FGF21 levels (HR: 2.011, 95% CI: [1.160-3.489]) proved to be a powerful tool in predicting the risk of MACEs among STEMI patients after emergency PCI. CONCLUSION: Elevated FGF21 levels on admission have been shown to be a powerful predictor of MACEs for STEMI patients after emergency PCI.

Effects of Mg and Sb Substitution on the Magnetic Properties of Magnetic Field Annealed MnBi Alloys.

Rare-earth-free permanent magnets have attracted considerable attention due to their favorable properties and applicability for cost-effective, high-efficiency, and sustainable energy devices. However, the magnetic field annealing process, which enhances the performance of permanent magnets, needs to be optimized for different magnetic fields and phases. Therefore, we investigated the effect of composition on the crystallization of amorphous MnBi to the ferromagnetic low-temperature phase (LTP). The optimal compositions and conditions were applied to magnetic field annealing under 2.5 T for elemental Mg- and Sb/Mg pair-substituted MnBi. The optimum MnBi composition for the highest purity LTP was determined to be Mn56Bi44, and its maximum energy product, (BH)max, was 5.62 MGOe. The Mg-substituted MnBi exhibited enhanced squareness (Mr/Ms), coercivity (Hc), and (BH)max values up to 0.8, 9659 Oe, and 5.64 MGOe, respectively, whereas the same values for the Sb/Mg pair-substituted MnBi were 0.76, 7038 Oe, and 5.60 MGOe, respectively. The substitution effects were also investigated using first-principles calculations. The density of states and total magnetic moments of Mn16Bi15Mg and Mn16Bi15Sb were similar to those of pure Mn16Bi16. Conversely, the Sb-substituted MnBi resulted in a dramatic enhancement in the anisotropy constant (K) from a small negative value (-0.85 MJ/m3) to a large positive value (6.042 MJ/m3).

Beating Thermal Deterioration of Magnetization with Mn4C and Exchange Bias in Mn⁻C Nanoparticles.

The magnetization of most materials decreases with increasing temperature due to thermal deterioration of magnetic ordering. Here, we show that Mn4C phase can compensate the magnetization loss due to thermal agitation. The Mn⁻C nanoparticles containing ferrimagnetic Mn4C and other Mn⁻C/Mn-O phases were prepared by using the traditional arc-discharge method. A positive temperature coefficient of magnetization (~0.0026 Am² kg-1 K-1) and an exchange bias up to 0.05 T were observed in the samples. We ascribe the exchange bias to the co-existence of ferrimagnetic Mn4C/Mn3O4 and antiferromagnetic α-Mn(C)/MnO phases. The positive temperature coefficient of magnetization of the samples was ascribed to the presence of Mn4C phase, which is considered as a Néel's P-type ferrimagnet.

In situ Observation of Phase Transformation in MnAl(C) Magnetic Materials.

The phase transformation in two modes, including both displacive and massive growth of τ-phase from ε-MnAl(C), was observed by in situ transmission electron microscopy. The exact temperature range for different phase transformation modes was determined by magnetic measurements. The displacive growth of ε→τ in Mn54Al46 (or Mn54Al46C2.44) occurs at temperatures below 650 K (or 766 K), above which both modes coexist. One-third or less of the ε-phase can be transformed into τ-phase via displacive mode while the remaining two-thirds or more via massive mode. In bulk τ-phase, most τ-nanocrystals formed via displacive mode are distributed in the matrix of large τ-grains that formed via massive mode. The typical massive growth rate of the τ-phase is 8-60 nm/s, while the displacive growth rate is low. A more complete understanding of the ε→τ phase transformations in the MnAl-based magnets was provided in this work, based on which the annealing process for ε→τ was optimized and thus high purity τ-phase with high saturation magnetization was obtained.

Evidence-based study on antithrombotic therapy in patients at risk of a stroke with paroxysmal atrial fibrillation.

The aim of the present study was to determine the optimal intensity of anticoagulation therapy in elderly patients with paroxysmal atrial fibrillation (PAF), using aspirin and varied concentrations of warfarin. Elderly patients with PAF (n=1,162) who met the inclusion criteria of the study and were at middle or high-risk of a stroke were investigated. Patients were divided into six groups (four high-risk groups and two middle-risk groups). Patients were treated with aspirin or varied concentrations of warfarin. The primary endpoint events, secondary endpoint events, major bleeding events and minor bleeding events were observed and compared. In high-risk elderly patients, warfarin significantly reduced primary and secondary endpoint events, total primary events and total events compared with aspirin. In middle-risk elderly patients, for all the events warfarin demonstrated no significant difference compared with aspirin. In high-risk patients with PAF, when the concentration of warfarin was adjusted to target international normalized ratio (INR) range 1.7-2.5, the primary and secondary endpoint events, total primary events and total events were significantly lower (P<0.05), compared with aspirin and warfarin at INR 1.2-1.6. When the intensity of warfarin was adjusted to the target INR 2.6-3.0, the primary and secondary endpoint events were significantly lower (P<0.05) compared with aspirin and warfarin INR at 1.2-1.6. This study determined that in high-risk elderly patients with PAF, warfarin is recommended for anticoagulation with an optimal INR range of 1.7-2.5. In patients at a middle-risk of a stroke, aspirin is the recommended treatment as an antithrombotic as results have indicated that there is limited benefit in the use of warfarin.

Ultrathin films of organic networks as nanofiltration membranes via solution-based molecular layer deposition.

Ultrathin films of organic networks on various substrates were fabricated through the solution-based molecular layer deposition (MLD) technique. The rigid tetrahedral geometries of polyfunctional amine and acyl chloride involved in the reaction ensure the continuity of the polymerization process. A linear increase in film thickness with respect to cycle number was observed by UV-vis adsorption, ellipsometry, and quartz crystal microbalance. The growth rate per MLD cycle is 1.6 nm, which can be controlled at the single molecular level. For the first time, we develop the MLD method on the top of hydrolyzed PAN substrate, resulting in nanofiltration (NF) membranes. The stepwise growth was monitored via attenuated total reflectance infrared studies. The separation performance of the obtained membrane for various solutes was sensitive to the terminated layers and number of cycles. The rejection of NH(2)-terminated membranes follows the order of CaCl(2) > Na(2)SO(4) > NaCl, while the order for COOH-capped surface is Na(2)SO(4) > CaCl(2) > NaCl. The absolute value of zeta potential for the MLD membranes decreases with the addition of deposition layers. The moderate water flux for the resulting membrane is due to the reduced porosity of the support as well as the low roughness and hydrophilicity of the membrane surface. This bottom-up process provides a promising approach for construction of long-term steady NF membranes with nanoscale dimensions.

Olmesartan attenuates the impairment of endothelial cells induced by oxidized low density lipoprotein through downregulating expression of LOX-1.

Oxidized low density lipoprotein (ox-LDL) and its receptor, lectin-Like ox-LDL receptor-1 (LOX-1), play important roles in the development of endothelial injuries. Olmesartan can protect endothelial cells from the impairment caused by various pathological stimulations. In the present study we investigated whether olmesartan decreased the impairment of endothelial cells induced by ox-LDL by exerting its effects on LOX-1 both in vitro and in vivo. Incubation of cultured endothelial cells of neonatal rats with ox-LDL for 24 h or infusion of ox-LDL in mice for 3 weeks led to the remarkable impairment of endothelial cells, including increased lactate dehydrogenase synthesis, phosphorylation of p38 mitogen-activated protein kinases (p38 MAPK) and expression of apoptotic genes such as B-cell leukemia/lymphoma 2 (Bcl-2)-associated X protein (Bax) and caspase-3. Simultaneously, the cell vitality and expression of Bcl-2 gene were greatly reduced. All these effects, however, were significantly suppressed by the treatment with olmesartan. Furthermore, ox-LDL promoted up-regulation of LOX-1 expression either in cultured endothelial cells or in the aortas of mice, which was reversed with the administration of olmesartan. Our data indicated that olmesartan may attenuate the impairment of endothelial cell via down-regulation of the increased LOX-1 expression induced by ox-LDL.