Change in patent foramen ovale height is associated with cryptogenic stroke and the construction of a morphology-based scoring system.

Introduction: Current guidelines recommended patent foramen ovale (PFO) occlusion as the preferred treatment for PFO-related cryptogenic stroke (CS); however, finding the causative foramen ovale remains challenging. This study aimed to identify predictors and establish a scoring system by assessing PFO morphology and stroke-related factors. Methods: Based on a prospective multicenter registered clinical trial, we compared data mainly derived from transesophageal echocardiography (TEE) and clinical history in patients with PFO-related CS and those without CS (non-CS) with incidental PFO. Subsequently, we explored independent predictors using logistic analysis, established a scoring system based on the results, and finally evaluated the scoring system using receiver operating characteristic (ROC) analysis and internal validation. Results: 75 patients with PFO-related CS and 147 non-CS patients were enrolled. Multivariate logistic analysis showed that the change in PFO height, large PFO, atrial septal aneurysm (ASA), and sustained right-to-left shunt (RLS) had independent relationships with CS. Based on the odds ratio value of each independent factor, a scoring system was built: change in PFO height ≥ 1.85 mm (3 points), large PFO (2 points), ASA (5 points), sustained RLS (2 points). 0-2 points correspond to low-risk PFO, 3-5 points medium-risk PFO, and 7-12 points high-risk PFO. ROC analysis showed an area under the curve of 0.80 to predict CS. The proportion of patients with CS is increasing based on these points. Conclusions: Our study screened out the change in PFO height as an independent predictor of CS. A simple and convenient scoring system can provide constructive guidance for identifying whether the PFO is causal and consequently selecting patients more likely to benefit from closure.

Regulating Fe-spin state by atomically dispersed Mn-N in Fe-N-C catalysts with high oxygen reduction activity.

As low-cost electrocatalysts for oxygen reduction reaction applied to fuel cells and metal-air batteries, atomic-dispersed transition metal-nitrogen-carbon materials are emerging, but the genuine mechanism thereof is still arguable. Herein, by rational design and synthesis of dual-metal atomically dispersed Fe,Mn/N-C catalyst as model object, we unravel that the O2 reduction preferentially takes place on FeIII in the FeN4 /C system with intermediate spin state which possesses one eg electron (t2g4eg1) readily penetrating the antibonding π-orbital of oxygen. Both magnetic measurements and theoretical calculation reveal that the adjacent atomically dispersed Mn-N moieties can effectively activate the FeIII sites by both spin-state transition and electronic modulation, rendering the excellent ORR performances of Fe,Mn/N-C in both alkaline and acidic media (halfwave positionals are 0.928 V in 0.1 M KOH, and 0.804 V in 0.1 M HClO4), and good durability, which outperforms and has almost the same activity of commercial Pt/C, respectively. In addition, it presents a superior power density of 160.8 mW cm-2 and long-term durability in reversible zinc-air batteries. The work brings new insight into the oxygen reduction reaction process on the metal-nitrogen-carbon active sites, undoubtedly leading the exploration towards high effective low-cost non-precious catalysts.

Scalable Synthesis of Micromesoporous Iron-Nitrogen-Doped Carbon as Highly Active and Stable Oxygen Reduction Electrocatalyst.

Micromesoporous metal-nitrogen-doped carbons have attracted incremental attention owning to their high activities for the electrocatalyzing oxygen reduction reaction (ORR). However, scalable synthesis of micromesoporous metal-nitrogen-doped carbons having superior electrocatalytic activity and stability remains a challenge. Here, an iron-nitrogen-doped carbon with highly electrocatalytic properties was simply prepared by ZnCl2 activation of an in situ polymerized iron-containing polypyrrole (PPy@FeClx) at high temperature. High yields of polypyrrole (∼98 wt %) and iron-nitrogen-doped carbon (∼47 wt %) could be reached. The eutectic state of FeClx-ZnCl2 and its derived ZnFe2O4 maskant played important roles in making micromesopores, scattering iron atoms, and trapping nitrogen atoms, leading to numerous micromesopore defects, a larger specific surface area, a more nitrogen doping content, and active sites for the material. The electrochemical tests and Zn-air battery measurements showed that the micromesoporous iron-nitrogen-doped carbon could achieve much positive onset and half-wave potentials at 0.98 and 0.90 V, respectively, as well as a large current density (6.06 mA/cm2) and good cycling stability. The combination of the iron-nitrogen doping and micromesopore defects by the eutectic salt activation method provided an effective way to scalable synthesize iron-nitrogen-doped carbon as highly active and stable oxygen reduction electrocatalytsts.

Rational inert-basal-plane activating design of ultrathin 1T' phase MoS2 with a MoO3 heterostructure for enhancing hydrogen evolution performances.

Activating both the inert basal plane and edge sites of molybdenum-disulphide (MoS2) is a significant yet challenging step in boosting their performance for the hydrogen evolution reaction (HER). In this study, the density functional theory calculation results show that the incorporation of MoO3 fragments leads to a slight out-of-plane distortion of the 1T-MoS2 phase of the resultant O-Mo-S framework, giving rise to a 1T'-MoS2/MoO3 heterostructure, where gap states around the Fermi level allow hydrogen evolution over both its basal plane (Mo-site) and edges (S-sites). Under the guidance of density functional theory, conducted via an efficient one-step solvothermal route, ultrathin metallic-phase 1T'-MoS2/MoO3 heterojunction nanosheets with 3D hollow structures and a very small size (d = ∼120 nm) were precisely designed and constructed. The electrochemical measurements show that such a material possesses a low overpotential at 10 mA cm-2 (η10, 109 mV) and a Tafel slope (42 mV dec-1). In addition, the HMHSs also led to excellent H2 production up to 22.108 mmol g-1 h-1 and good durability under the photocatalytic process. To the best of our knowledge, the performance of this catalyst is better than that of most previously reported Mo-based non-noble catalysts for the HER. The excellent HER activity of this catalyst is highlighted by its unique synergistic effect between 1T'-MoS2 and MoO3 with an activated inert basal plane and fantastic hollow structure with a large surface area and high content of edge sites.