Coupling urea oxidation reaction (UOR) with hydrogen evolution reaction (HER) is an effective energy‐saving technique for hydrogen generation. However, exploring efficient bifunctional ...electrocatalysts under high current density is still challenging. Herein, hierarchical Fe doped cobalt selenide coupled with FeCo layered double hydroxide (Fe‐Co0.85Se/FeCo LDH) array as a self‐supported superior bifunctional heterojunction electrode is rationally designed for both UOR and HER. The unique heterostructure facilitates electron transfer and interface interactions through local interfacial Co‐Se/O‐Fe bonding environment modulation, improving reaction kinetics and intrinsic activity. As a result, the heterostructured electrocatalyst exhibits ultralow potentials of −0.274 and 1.48 V to reach 500 mA cm−2 for catalyzing the HER and UOR, respectively. Particularly, the full urea electrolysis system driven by Fe‐Co0.85Se/FeCo LDH delivers 300 mA cm−2 at a relatively low potential of 1.57 V, which is 150 mV lower than the conventional water electrolysis. The combination of in situ characterization and theoretical analysis reveal that the active sites with the adjustable electronic environment are induced by the interfacial bonding of the heterojunction, facilitating the water decomposition of HER and the stabilization of intermediates in UOR. This work inspires the interfacial environment modulation to optimize advanced electrocatalysts for energy‐saving H2 production.
The heterostructure constructed by Fe doped Co0.85Se and FeCo LDH can induce the modulation of local interfacial bonding environment and optimize the d‐band center to benefit the intermediates adsorption/desorption during urea oxidation reaction. As a result, a low cell voltage of 1.57 V at 300 mA cm−2 for urea water splitting is achieved based on the heterostructure.
Designing well‐defined interfacial chemical bond bridges is an effective strategy to optimize the catalytic activity of metal–organic frameworks (MOFs), but it remains challenging. Herein, a facile ...in situ growth strategy is reported for the synthesis of tightly connected 2D/2D heterostructures by coupling MXene with CoBDC nanosheets. The multifunctional MXene nanosheets with high conductivity and ideal hydrophilicity as bridging carriers can ensure structural stability and sufficient exposure to active sites. Moreover, the Co–O–Ti bond bridging formed at the interface effectively triggers the charge transfer and modulates the electronic structure of the Co‐active site, which enhances the reaction kinetics. As a result, the optimized CoBDC/MXene exhibits superior hydrogen evolution reaction (HER) activity with low overpotentials of 29, 41, and 76 mV at 10 mA cm−2 in alkaline, acidic, and neutral electrolytes, respectively, which is comparable to commercial Pt/C. Theoretical calculation demonstrates that the interfacial bridging‐induced electron redistribution optimizes the free energy of water dissociation and hydrogen adsorption, resulting in improved hydrogen evolution. This study not only provides a novel electrocatalyst for efficient HER at all pH conditions but also opens up a new avenue for designing highly active catalytic systems.
A novel CoBDC/MXene electrocatalyst with 2D/2D heterostructure is prepared by a facile in situ growth strategy, in which the formation of interfacial Co–O–Ti bridges effectively tunes the electron distribution and catalytic reaction energy barrier, leading to ultralow hydrogen evolution reaction overpotentials at all pH conditions.
Emerging evidence suggests that gut microbiome composition alterations affect neurodegeneration through neuroinflammation in the pathogenesis of Parkinson's disease (PD). Here, we evaluate gut ...microbiota alterations and host cytokine responses in a population of Taiwanese patients with PD.
Fecal microbiota communities from 80 patients with PD and 77 age and gender-matched controls were assessed by sequencing the V3-V4 region of the 16S ribosomal RNA gene. Diet and comorbidities were controlled in the analyses. Plasma concentrations of IL-1β, IL-2, IL-4, IL-6, IL-13, IL-18, GM-CSF, IFNγ, and TNFα were measured by a multiplex immunoassay and relationships between microbiota, clinical characteristics, and cytokine levels were analyzed in the PD group. We further examined the cytokine changes associated with the altered gut microbiota seen in patients with PD in another independent cohort of 120 PD patients and 120 controls.
Microbiota from patients with PD was altered relative to controls and dominated by Verrucomicrobia, Mucispirillum, Porphyromonas, Lactobacillus, and Parabacteroides. In contrast, Prevotella was more abundant in controls. The abundances of Bacteroides were more increased in patients with non-tremor PD subtype than patients with tremor subtype. Bacteroides abundance was correlated with motor symptom severity defined by UPDRS part III motor scores (rho = 0.637 95% confidence interval 0.474 to 0.758, P < 0.01). Altered microbiota was correlated with plasma concentrations of IFNγ and TNFα. There was a correlation between Bacteroides and plasma level of TNFα (rho = 0.638 95% CI: 0.102-0.887, P = 0.02); and a correlation between Verrucomicrobia abundance and plasma concentrations of IFNγ (rho = 0.545 95% CI - 0.043-0.852, P = 0.05). The elevated plasma cytokine responses were confirmed in an additional independent 120 patients with PD and 120 controls (TNFα: PD vs. control 8.51 ± 4.63 pg/ml vs. 4.82 ± 2.23 pg/ml, P < 0.01; and IFNγ: PD vs. control: 38.45 ± 7.12 pg/ml vs. 32.79 ± 8.03 pg/ml, P = 0.03).
This study reveals altered gut microbiota in PD and its correlation with clinical phenotypes and severity in our population. The altered plasma cytokine profiles associated with gut microbiome composition alterations suggest aberrant immune responses may contribute to inflammatory processes in PD.
Rational heterointerface engineering is crucial for superior and robust hydrogen evolution reaction (HER). Herein, a delicate organic‐inorganic hybrid heterojunction based on the assembly of oxalate ...with polyaniline (PANI) for HER at high‐current‐densities is envisioned. Strong π–d electron coupling is achieved between the delocalized π electrons of PANI and the localized d electrons of oxalate metal sites. The CoC2O4 nanosheets are grown on nickel foam (NF) with Ni2+ ions substitution by the precursor etching. By virtue of the synergy of hetero ions and π–d electron coupling, metal sites obtain sufficient exposure and electronic structure optimization. Surprisingly, the phase transition of oxalate during HER in the alkaline environment does not weaken the π–d electronic coupling of the organic‐inorganic hybrid interfaces. Inheritable interfacial electron interaction provides a reliable guarantee for robust stability at high‐current‐densities while endowing the hybrid materials with extremely low overpotentials. As expected, post‐phase reconstructed Co0.59Ni0.41(OH)2@PANI/NF displays impressive HER activity, with a low overpotential of 43 mV@−10 mA cm−2 and robust stability at −1000 mA cm−2 for 30 h in the alkaline environment. This study sheds light on the rational heterostructure interface design and promotes the architecture of an impressive electrocatalysts system.
This study constructs robust organic‐inorganic hybrid interfaces between bimetallic oxalate and polyaniline with strong π–d electronic coupling. The oxalate undergoes phase reconstruction to form hydroxide during hydrogen evolution reaction (HER) in the alkaline environment. Benefiting from the strong electronic coupling, the hybrid interfaces after the reconstruction remain structurally stable to achieve superior HER activity at high‐current‐densities.
Modulating the microenvironment of single‐atom catalysts (SACs) is critical to optimizing catalytic activity. Herein, we innovatively propose a strategy to improve the local reaction environment of ...Ru single atoms by precisely switching the crystallinity of the support from high crystalline and low crystalline, which significantly improves the hydrogen evolution reaction (HER) activity. The Ru single‐atom catalyst anchored on low‐crystalline nickel hydroxide (Ru−LC−Ni(OH)2) reconstructs the distribution balance of the interfacial ions due to the activation effect of metal dangling bonds on the support. Single‐site Ru with a low oxidation state induces the aggregation of hydronium ions (H3O+), leading to the formation of a local acidic microenvironment in alkaline media, breaking the pH‐dependent HER activity. As a comparison, the Ru single‐atom catalyst anchored on high‐crystalline nickel hydroxide (Ru−HC−Ni(OH)2) exhibits a sluggish Volmer step and a conventional local reaction environment. As expected, Ru−LC−Ni(OH)2 requires low overpotentials of 9 and 136 mV at 10 and 1000 mA cm−2 in alkaline conditions and operates stably at 500 mA cm−2 for 500 h in an alkaline seawater anion exchange membrane (AEM) electrolyzer. This study provides a new perspective for constructing highly active single‐atom electrocatalysts.
The local acidic microenvironment of a single‐atom Ru catalyst is modulated by switching the crystallinity of the support, thus breaking the pH‐dependent alkaline HER activity.
A major challenge to end the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is to develop a broadly protective vaccine that elicits long-term immunity. As the key ...immunogen, the viral surface spike (S) protein is frequently mutated, and conserved epitopes are shielded by glycans. Here, we revealed that S protein glycosylation has site-differential effects on viral infectivity. We found that S protein generated by lung epithelial cells has glycoforms associated with increased infectivity. Compared to the fully glycosylated S protein, immunization of S protein with N-glycans trimmed to the mono-GlcNAc-decorated state (S
) elicited stronger immune responses and better protection for human angiotensin-converting enzyme 2 (hACE2) transgenic mice against variants of concern (VOCs). In addition, a broadly neutralizing monoclonal antibody was identified from S
-immunized mice that could neutralize wild-type SARS-CoV-2 and VOCs with subpicomolar potency. Together, these results demonstrate that removal of glycan shields to better expose the conserved sequences has the potential to be an effective and simple approach for developing a broadly protective SARS-CoV-2 vaccine.
Developing efficient and durable electrocatalysts for the oxygen evolution reaction (OER) in proton exchange membrane (PEM) electrolyzers represents a significant challenge. Herein, the ...cobalt‐ruthenium oxide nano‐heterostructures are successfully synthesized on carbon cloth (CoOx/RuOx‐CC) for acidic OER through a simple and fast solution combustion strategy. The rapid oxidation process endows CoOx/RuOx‐CC with abundant interfacial sites and defect structures, which enhances the number of active sites and the charge transfer at the electrolyte‐catalyst interface, promoting the OER kinetics. Moreover, the electron supply effect of the CoOx support allows electrons to transfer from Co to Ru sites during the OER process, which is beneficial to alleviate the ion leaching and over‐oxidation of Ru sites, improving the catalyst activity and stability. As a self‐supported electrocatalyst, CoOx/RuOx‐CC displays an ultralow overpotential of 180 mV at 10 mA cm−2 for OER. Notably, the PEM electrolyzer using CoOx/RuOx‐CC as the anode can be operated at 100 mA cm−2 stably for 100 h. Mechanistic analysis shows that the strong catalyst‐support interaction is beneficial to redistribute the electronic structure of RuO bond to weaken its covalency, thereby optimizing the binding energy of OER intermediates and lowering the reaction energy barrier.
The electron supply effect of the CoOx support effectively prevents the over‐oxidation and ion leaching of the active sites in RuOx during the acidic OER process, achieving simultaneous enhancement of catalytic activity and stability. The CoOx/RuOx‐CC heterostructure exhibits excellent OER performance with a low overpotential (180 mV@10 mA cm−2) and long‐term stability (60 h@10 mA cm−2).
Direct lineage reprogramming is a promising approach for human disease modeling and regenerative medicine, with poorly understood mechanisms. Here, we reveal a hierarchical mechanism in the direct ...conversion of fibroblasts into induced neuronal (iN) cells mediated by the transcription factors Ascl1, Brn2, and Myt1l. Ascl1 acts as an “on-target” pioneer factor by immediately occupying most cognate genomic sites in fibroblasts. In contrast, Brn2 and Myt1l do not access fibroblast chromatin productively on their own; instead, Ascl1 recruits Brn2 to Ascl1 sites genome wide. A unique trivalent chromatin signature in the host cells predicts the permissiveness for Ascl1 pioneering activity among different cell types. Finally, we identified Zfp238 as a key Ascl1 target gene that can partially substitute for Ascl1 during iN cell reprogramming. Thus, a precise match between pioneer factors and the chromatin context at key target genes is determinative for transdifferentiation to neurons and likely other cell types.
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•Ascl1 has pioneer activity, accessing closed chromatin to allow other factors to bind•Unlike other pioneer factors, Ascl1 binds its physiologic neural targets in fibroblasts•A trivalent chromatin domain predicts iN reprogramming ability in other cell types•Zfp238 is a direct Ascl1 target and critical mediator of iN cell reprogramming
Of three transcription factors that together convert different cell types into induced neuronal (iN) cells, Ascl1 leads the way as the “pioneer factor,” followed by Brn2 and Myt1l. A trivalent chromatin state at Ascl1 target genes predicts which types of cells will respond to reprogramming by these factors.
Obesity is not only viewed as a chronic aggressive disorder but is also associated with an increased risk for various diseases. Nonetheless, new anti-obesity drugs are an urgent need since few ...pharmacological choices are available on the market. Natural compounds have served as templates for drug discovery, whereas modified molecules from the leads identified based on in vitro models often reveal noncorresponding bioactivity between in vitro and in vivo studies. Therefore, to provide inspiration for the exploration of innovative anti-obesity agents, recent discoveries of natural anti-obesity compounds with in vivo evidence have been summarized according to their chemical structures, and the comparable efficacy of these compounds is categorized using animal models. In addition, several synthetic derivatives optimized from the phytochemicals are also provided to discuss medicinal chemistry achievements guided by natural sources.
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•Phenotypic discovery of anti-obesity phytochemicals in the light of in vivo models.•Individual compounds perform multiple mechanisms of action to manage obesity.•The weight-loss efficacy of the natural compounds is compared.•Synthetic derivatives built from these natural scaffolds are reviewed.
Approaches to differentiating pluripotent stem cells (PSCs) into neurons currently face two major challenges-(i) generated cells are immature, with limited functional properties; and (ii) cultures ...exhibit heterogeneous neuronal subtypes and maturation stages. Using lineage-determining transcription factors, we previously developed a single-step method to generate glutamatergic neurons from human PSCs. Here, we show that transient expression of the transcription factors Ascl1 and Dlx2 (AD) induces the generation of exclusively GABAergic neurons from human PSCs with a high degree of synaptic maturation. These AD-induced neuronal (iN) cells represent largely nonoverlapping populations of GABAergic neurons that express various subtype-specific markers. We further used AD-iN cells to establish that human collybistin, the loss of gene function of which causes severe encephalopathy, is required for inhibitory synaptic function. The generation of defined populations of functionally mature human GABAergic neurons represents an important step toward enabling the study of diseases affecting inhibitory synaptic transmission.
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