Low-Electronegativity Mn-Contraction of PtMn Nanodendrites Boosts Oxygen Reduction Durability.

Platinum metal (PtM, M=Ni, Fe, Co) alloys catalysts show high oxygen reduction reaction (ORR) activity due to their well-known strain and ligand effects. However, these PtM alloys usually suffer from a deficient ORR durability in acidic environment as the alloyed metal is prone to be dissolved due to its high electronegativity. Herein, we report a new class of PtMn alloy nanodendrite catalyst with low-electronegativity Mn-contraction for boosting the oxygen reduction durability of fuel cells. The moderate strain in PtMn, induced by Mn contraction, yields optimal oxygen reduction activity at 0.53 A mg-1 at 0.9 V versus reversible hydrogen electrode (RHE). Most importantly, we show that relative to well-known high-electronegativity Ni-based Pt alloy counterpart, the PtMn nanodendrite catalyst experiences less transition metals' dissolution in acidic solution and achieves an outstanding mass activity retention of 96 % after 10,000 degradation cycles. Density functional theory calculation reveals that PtMn alloys are thermodynamically more stable than PtNi alloys in terms of formation enthalpy and cohesive energy. The PtMn nanodendrite-based membrane electrode assembly delivers an outstanding peak power density of 1.36 W cm-2 at a low Pt loading and high-performance retention over 50 h operations at 0.6 V in H2 -O2 hydrogen fuel cells.

Two-Dimensional Anti-Van't Hoff/Le Bel Array AlB6 with High Stability, Unique Motif, Triple Dirac Cones, and Superconductivity.

We report the discovery of a rule-breaking two-dimensional aluminum boride (AlB6-ptAl-array) nanosheet with a planar tetracoordinate aluminum (ptAl) array in a tetragonal lattice by comprehensive crystal structure search, first-principles calculations, and molecular dynamics simulations. It is a brand new 2D material with a unique motif, high stability, and exotic properties. These anti-van't Hoff/Le Bel ptAl-arrays are arranged in a highly ordered way and connected by two sheets of boron rhomboidal strips above and below the array. The regular alignment and strong bonding between the constituents of this material lead to very strong mechanical strength (in-plane Young's modulus Y x = 379, Y y = 437 N/m, much larger than that of graphene, Y = 340 N/m) and high thermal stability (the framework survived simulated annealing at 2080 K for 10 ps). Additionally, electronic structure calculations indicate that it is a rare new material with triple Dirac cones, Dirac-like fermions, and node-loop features. Remarkably, this material is predicted to be a 2D phonon-mediated superconductor with Tc = 4.7 K, higher than the boiling point of liquid helium (4.2 K). Surprisingly, the Tc can be greatly enhanced up to 30 K by applying tensile strain at 12%. This is much higher than the temperature of liquid hydrogen (20.3 K). These outstanding properties may pave the way for potential applications of an AlB6-ptAl-array in nanoelectronics and nanomechanics. This work opens up a new branch of two-dimensional aluminum boride materials for exploration. The present study also opens a field of two-dimensional arrays of anti-van't Hoff/Le Bel motifs for study.

Diatomic Active Sites Embedded Graphyne as Electrocatalysts for Ammonia Synthesis.

Ammonia (NH3) is a vital chemical compound in industry and agriculture, and the electrochemical nitrogen reduction reaction (eNRR) is considered a promising approach for NH3 synthesis. However, the development of eNRR faces the challenge of high overpotential and low Faradaic efficiency. In this work, graphyne (GY) is anchored by 3d, 4d, and 5d dual transition metal atoms to form diatomic catalysts (DACs) and is roundly investigated as an electrocatalyst for eNRR via density functional theory calculations. Due to the protrusion of anchored metal atoms, the active sites of GY are better exposed compared to other substrates, exhibiting higher activity. Through four-step hierarchical high-throughput screening (ΔG*N2 < 0 eV, ΔG*N2 â†’ *N2H < 0.4 eV, ΔG*NH2 â†’ *NH3 < 0.4 eV, and ΔG*N2 < ΔG*H), the number of selected catalysts in each step is 325, 240, 145, and 20, respectively. Considering a series of factors, including stability, initial potential, and selectivity, 13 kinds of eligible catalysts are identified. Optimal eNRR paths studies show that the best catalyst Mn2@GY features no onset potential. For the three catalysts (Mn2@GY, Ir2@GY, and RhOs@GY), the onset potentials of the most favorable eNRR pathways are -0.07, -0.12, and -0.17 V, respectively. The excellent catalytic activity can be credited to the effective charge transfer and orbital interaction between the active site and adsorbed N2. Our work demonstrates the significance of DACs for ammonia synthesis and provides a paradigm for the study of DACs even for other important reactions.

Causal links between gut microbiomes, cytokines and risk of different subtypes of epilepsy: a Mendelian randomization study.

Objective: Recent research suggests a potential link between the gut microbiome (GM) and epilepsy. We undertook a Mendelian randomization (MR) study to determine the possible causal influence of GM on epilepsy and its various subtypes, and explore whether cytokines act as mediators. Methods: We utilized Genome-Wide Association Study (GWAS) summary statistics to examine the causal relationships between GM, cytokines, and four epilepsy subtypes. Furthermore, we assessed whether cytokines mediate the relationship between GM and epilepsy. Significant GMs were further investigated using transcriptomic MR analysis with genes mapped from the FUMA GWAS. Sensitivity analyses and reverse MR were conducted for validation, and false discovery rate (FDR) correction was applied for multiple comparisons. Results: We pinpointed causal relationships between 30 GMs and various epilepsy subtypes. Notably, the Family Veillonellaceae (OR:1.03, 95%CI:1.02-1.05, p = 0.0003) consistently showed a strong positive association with child absence epilepsy, and this causal association endured even after FDR correction (p-FDR < 0.05). Seven cytokines were significantly associated with epilepsy and its subtypes. A mediating role for cytokines has not been demonstrated. Sensitivity tests validated the primary MR analysis outcomes. Additionally, no reverse causality was detected between significant GMs and epilepsy. Of the mapped genes of notable GMs, genes like BLK, FDFT1, DOK2, FAM167A, ZSCAN9, RNGTT, RBM47, DNAJC21, SUMF1, TCF20, GLO1, TMTC1, VAV2, and RNF14 exhibited a profound correlation with the risk factors of epilepsy subtypes. Conclusion: Our research validates the causal role of GMs and cytokines in various epilepsy subtypes, and there has been no evidence that cytokines play a mediating role between GM and epilepsy. This could provide fresh perspectives for the prevention and treatment of epilepsy.

Novel insights into causal effects of serum lipids, lipid metabolites, and lipid-modifying targets on the risk of intracerebral aneurysm.

INTRODUCTION: Different serum lipid and lipid-lowering agents are reported to be related to the occurrence of intracerebral aneurysm (IA). However, the causal relationship between them requires further investigation. PATIENTS AND METHODS: Mendelian randomization (MR) analysis was performed on IA and its subtypes by using instrumental variants associated with six serum lipids, 249 lipid metabolic traits, and 10 lipid-lowering agents that were extracted from the largest genome-wide association study. Phenome-wide MR analyses were conducted to identify potential phenotypes associated with significant lipid-lowering agents. RESULTS: After multiple comparison adjustments (p < 0.0083), genetically proxied triglyceride (TG) (odds ratio [OR] 1.25, 95% confidence interval [CI] 1.07-1.47, p = 0.005) and high-density lipoprotein cholesterol (HDL-C) levels (OR 0.93, 95% CI 0.89-0.98, p = 0.008) showed causal relationships with the risk of IA. Four lipid metabolic traits showed a causal relationship with the risk of IA (p < 0.0002). As confirmed by drug target MR, the causal relationship between the HMGCR target and IA, HMGCR target and subarachnoid hemorrhage (SAH), ANGPTL3 target and SAH, CETP target, and SAH remained statistically significant after multiple adjustments (p < 0.005). Additionally, phenome-wide MR did not identify other diseases linked to the significant lipid-lowering agent (p < 6.39 × 10-5). DISCUSSION AND CONCLUSION: This study not only supports that serum lipids (TG and HDL-C) are associated with IA but also confirms the positive effect and absence of safety concerns of intervening HMGCR, ANGPTL3, and CETP targets in IA and its subtypes, opening new avenues for IA treatment.

Metabolome-Wide Mendelian Randomization Assessing the Causal Role of Serum and Cerebrospinal Metabolites in Traumatic Brain Injury.

Previous studies have identified metabolites as biomarkers or potential therapeutic targets for traumatic brain injury (TBI). However, the causal association between them remains unknown. Therefore, we investigated the causal effect of serum metabolites and cerebrospinal fluid (CSF) metabolites on TBI susceptibility through Mendelian randomization (MR). Genetic variants related to metabolites and TBI were extracted from a corresponding genome-wide association study (GWAS). Causal effects were estimated through the inverse variance weighted approach, supplemented by a weighted median, weight mode, and the MR-Egger test. In addition, sensitivity analyses were further performed to evaluate the stability of the MR results, including the MR-Egger intercept, leave-one-out analysis, Cochrane's Q-test, and the MR-PRESSO global test. Metabolic pathway analysis was applied to uncover the underlying pathways of the significant metabolites in TBI. In blood metabolites, substances such as 4-acetaminophen sulfate and kynurenine showed positive links, whereas beta-hydroxyisovalerate and creatinine exhibited negative correlations. CSF metabolites such as N-formylanthranilic acid were positively related, while kynurenate showed negative associations. The metabolic pathway analysis highlighted the potential biological pathways involved in TBI. Of these 16 serum metabolites, 11 CSF metabolites and metabolic pathways may serve as useful circulating biomarkers in clinical screening and prevention, and may be candidate molecules for the exploration of mechanisms and drug targets.

Causal association of leisure sedentary behavior and cervical spondylosis, sciatica, intervertebral disk disorders, and low back pain: a Mendelian randomization study.

Background: Some studies suggest sedentary behavior is a risk factor for musculoskeletal disorders. This study aimed to investigate the potential causal association between leisure sedentary behavior (LSB) (including television (TV) viewing, computer use, and driving) and the incidence of sciatica, intervertebral disk degeneration (IVDD), low back pain (LBP), and cervical spondylosis (CS). Methods: We obtained the data of LSB, CS, IVDD, LBP, sciatica and proposed mediators from the gene-wide association studies (GWAS). The causal effects were examined by Inverse Variance Weighted (IVW) test, MR-Egger, weighted median, weighted mode and simple mode. And sensitivity analysis was performed using MR-Pleiotropy Residual Sum and Outlier (MR-PRESSO) and MR-Egger intercept test. Multivariable MR (MVMR) was conducted to investigate the independent factor of other LSB; while two-step MR analysis was used to explore the potential mediators including Body mass index (BMI), smoking initiation, type 2 diabetes mellitus (T2DM), major depressive disorder (MDD), schizophrenia, bipolar disorder between the causal association of LSB and these diseases based on previous studies. Results: Genetically associated TV viewing was positively associated with the risk of CS (OR = 1.61, 95%CI = 1.25 to 2.07, p = 0.002), IVDD (OR = 2.10, 95%CI = 1.77 to 2.48, p = 3.79 × 10-18), LBP (OR = 1.84, 95%CI = 1.53 to 2.21, p = 1.04 × 10-10) and sciatica (OR = 1.82, 95% CI = 1.45 to 2.27, p = 1.42 × 10-7). While computer use was associated with a reduced risk of IVDD (OR = 0.66, 95%CI = 0.55 to 0.79, p = 8.06 × 10-6), LBP (OR = 0.49, 95%CI = 0.40 to 0.59, p = 2.68 × 10-13) and sciatica (OR = 0.58, 95%CI = 0.46 to 0.75, p = 1.98 × 10-5). Sensitivity analysis validated the robustness of MR outcomes. MVMR analysis showed that the causal effect of TV viewing on IVDD (OR = 1.59, 95%CI = 1.13 to 2.25, p = 0.008), LBP (OR = 2.15, 95%CI = 1.50 to 3.08, p = 3.38 × 10-5), and sciatica (OR = 1.61, 95%CI = 1.03 to 2.52, p = 0.037) was independent of other LSB. Furthermore, two-step MR analysis indicated that BMI, smoking initiation, T2DM may mediate the causal effect of TV viewing on these diseases. Conclusion: This study provides empirical evidence supporting a positive causal association between TV viewing and sciatica, IVDD and LBP, which were potentially mediated by BMI, smoking initiation and T2DM.

Two-Dimensional Single-Atom Catalyst TM3(HAB)2 Monolayers for Electrocatalytic Dinitrogen Reduction Using Hierarchical High-Throughput Screening.

As an environmentally friendly and sustainable strategy to produce ammonia, the electrocatalytic nitrogen reduction reaction (eNRR) is facing the challenge of low conversion rates and high overpotential, to solve which efficient catalysts are urgently needed. Here, a new class of two-dimensional metal-organic layers (MOLs) TM3(HAB)2 (TM = 30 transition metals; HAB = hexaaminobenzene) were evaluated via a three-step high-throughput screening combined with the spin-polarized density functional theory (DFT) method to obtain eligible TM3(HAB)2 catalysts embedded with transition metal atoms from 3d to 5d. Our investigation revealed that Nb3(HAB)2, Mo3(HAB)2, and Tc3(HAB)2 are eligible NRR candidates, among which Tc3(HAB)2 possesses the best catalytic performance with a lowest onset potential of -0.63 V via both distal and alternating pathways and an ultralow NH3 desorption free energy of 0.22 eV. Furthermore, the band structures of three catalysts show their nice conductivity. The corresponding projected density of states (PDOS) illustrate that high catalytic activity can be ascribed to apparent orbital hybridization and charge transfer between catalysts and adsorbed N2. Later, stability and selectivity of all three candidates were computed, Tc3(HAB)2 and Nb3(HAB)2 catalysts are proved to facilitate dinitrogen reduction and exhibit good stability and high selectivity, yet NRR on the Mo3(HAB)2 catalyst is inhibited by hydrogen evolution reaction (HER). Based on the abovementioned studies, we concluded that Tc3(HAB)2 and Nb3(HAB)2 monolayers are promising catalysts for nitrogen fixation. We expect this work to fill the gap of exploring more eligible single-atom catalysts (SACs) anchored with transition metal atoms on MOLs for NRR.