Abstract
Electrochemical CO
2
reduction to multicarbon products faces challenges of unsatisfactory selectivity, productivity, and long-term stability. Herein, we demonstrate CO
2
electroreduction in ...strongly acidic electrolyte (pH ≤ 1) on electrochemically reduced porous Cu nanosheets by combining the confinement effect and cation effect to synergistically modulate the local microenvironment. A Faradaic efficiency of 83.7 ± 1.4% and partial current density of 0.56 ± 0.02 A cm
−2
, single-pass carbon efficiency of 54.4%, and stable electrolysis of 30 h in a flow cell are demonstrated for multicarbon products in a strongly acidic aqueous electrolyte consisting of sulfuric acid and KCl with pH ≤ 1. Mechanistically, the accumulated species (e.g., K
+
and OH
−
) on the Helmholtz plane account for the selectivity and activity toward multicarbon products by kinetically reducing the proton coverage and thermodynamically favoring the CO
2
conversion. We find that the K
+
cations facilitate C-C coupling through local interaction between K
+
and the key intermediate *OCCO.
•We analyzed the changes, trade-offs, and synergies of ESs in an ecological barrier.•We compared evolutionary mechanisms and interactions of ESs at different scales.•Multi-factors jointly affected ...the bundles and associated relationships of ESs.
Located in the hilly and mountainous central area of the national ecological security strategic pattern (described as “two ecological barriers and three green belts”), southern Jiangxi is an important ecological barrier in southeast China and a pilot area for the national mountains-rivers-forests-farmlands-lakes-grasslands restoration projects. In recent years, the rapid economic development of the southern Jiangxi region and the rapid changes in land use, agricultural intensification, and population urbanization have severely tested this ecosystem on which people depend for their survival. Currently, studies of ecosystems and their interactions from a single spatial perspective have sprung up, but only a few studies have comprehensively analyzed different spatial scales to facilitate the sustainable development of regional ecosystems. Multi-scale studies should be carried out to quantitatively understand the relationship between ecosystem services (ESs) and socio-natural drivers, in an attempt to find a suitable scale to assess regional ESs or to achieve complementary advantages by combining multi-scales so as to conduct hierarchical management of ESs. Therefore, to better understand the interplay between ESs and to achieve the goals of sustainable development, we quantitatively analyzed the evolutionary patterns, trade-offs, and synergies of ESs. In our analysis, we also looked at bundling ESs and their drivers for seven ecosystem services at the township and watershed scales for 2000–2020 in southern Jiangxi. Crop production, meat production, water yield, carbon storage, soil retention, habitat quality, and forest recreation services were specifically quantified, and redundancy analysis was used to explore the influence degree of precipitation, temperature, elevation, slope, GDP, and population density on ESs. The results showed that most ESs have increased in southern Jiangxi, indicating spatial and temporal heterogeneity. The scale effect of trade-off and synergy showed that the spatial variation was similar, but the amplitude of variation was different. Compared with the watershed scale, the overall bundle of ESs in southern Jiangxi is better identified and clustered at the township scale. In addition, Cluster 4 at the township scale and Cluster 3 at the watershed scale can comprehensively identify high-value areas of ecosystem services in the study area. The rapid growth of GDP and population density caused by rapid urbanization were the main driving factors of the difference in ESs between the two scales in southern Jiangxi. Our results provide recommendations for governance and restoration of regional ecosystem services and support for conducting a comprehensive analysis of spatio-temporal evolutionary mechanisms and interactions of ecosystem services at different scales.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
Atomically dispersed transition metals on carbon-based aromatic substrates are an emerging class of electrocatalysts for the electroreduction of CO
2
. However, electron delocalization of ...the metal site with the carbon support via d-π conjugation strongly hinders CO
2
activation at the active metal centers. Herein, we introduce a strategy to attenuate the d-π conjugation at single Ni atomic sites by functionalizing the support with cyano moieties. In situ attenuated total reflection infrared spectroscopy and theoretical calculations demonstrate that this strategy increases the electron density around the metal centers and facilitates CO
2
activation. As a result, for the electroreduction of CO
2
to CO in aqueous KHCO
3
electrolyte, the cyano-modified catalyst exhibits a turnover frequency of ~22,000 per hour at −1.178 V versus the reversible hydrogen electrode (RHE) and maintains a Faradaic efficiency (FE) above 90% even with a CO
2
concentration of only 30% in an H-type cell. In a flow cell under pure CO
2
at −0.93 V versus RHE the cyano-modified catalyst enables a current density of −300 mA/cm
2
with a FE above 90%.
Chronic stress-induced brain injury (CSBI) is the organic damage of brain tissue caused by long-term psychological and environmental stress. However, there is no effective drug for the treatment of ...CSBI. The present study aimed to investigate possible mechanisms of CSBI and to explore related therapeutic targets. A rat model of CSBI was established by combining chronic restraint and cold water immersion. Our CSBI model was validated via Nissl staining, Western blotting, and behavioral tests. RNA sequencing (RNA-seq) was used to identify differentially expressed genes (DEGs) within brain tissue during CSBI. Both Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses were performed to determine signaling pathways associated with CSBI-induced DEGs. Agonists/antagonists were used to validate the pharmacodynamics of potential therapeutic targets. A combination of chronic restraint and cold water immersion successfully induced a rat model of CSBI, as indicated by various markers of brain injury and cell apoptosis that were verified via Nissl staining, Western blotting, and behavioral tests. RNA-seq analysis identified 1131 DEGs in CSBI rats. Of these DEGs, 553 genes were up-regulated and 778 genes were down-regulated. GO and KEGG pathway analyses revealed that significant DEGs were predominantly related to membrane-bound ion channels, among which the potassium channel function was found to be significantly affected. Pharmacological experiments revealed that retigabine, a voltage-gated potassium channel opener, demonstrated a protective effect in CSBI rats. Taken together, our findings suggest that potassium channel function is disrupted in CSBI, and that potassium channel regulators may function as anti-CSBI drugs.
Growth plate cartilage has limited self-repair ability, leading to poor bone bridge formation post-injury and ultimately limb growth defects in children. The current corrective surgeries are highly ...invasive, and outcomes can be unpredictable. Following growth plate injury, the direct loss of extracellular matrix (ECM) coupled with further ECM depletion due to the inhibitory effects of inflammation on the cartilage matrix protein greatly hinder chondrocyte regeneration. We designed an exosome (Exo) derived from bone marrow mesenchymal stem cells (BMSCs) loaded ECM-mimic hydrogel to promote cartilage repair by directly supplementing ECM and anti-inflammatory properties. Aldehyde-functionalized chondroitin sulfate (OCS) was introduced into gelatin methacryloyl (GM) to form GMOCS hydrogel. Our results uncovered that GMOCS hydrogel could significantly promote the synthesis of ECM due to the doping of OCS. In addition, the GMOCS-Exos hydrogel could further promote the anabolism of chondrocytes by inhibiting inflammation and ultimately promote growth plate injury repair through ECM remodeling.
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•Chondrocytes are difficult to regenerate after growth plate injury due to extensive degradation of ECM (extracellular matrix).•GMOCS-Exos can promote the synthesis of ECM by directly supplementing ECM and anti-inflammatory properties.•GMOCS-Exos can boost cartilage regeneration after growth plate injury and reduce bone bridge formation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Nitrate (NO
) pollution poses significant threats to water quality and global nitrogen cycles. Alkaline electrocatalytic NO
reduction reaction (NO
RR) emerges as an attractive route for enabling NO
...removal and sustainable ammonia (NH
) synthesis. However, it suffers from insufficient proton (H
) supply in high pH conditions, restricting NO
-to-NH
activity. Herein, we propose a halogen-mediated H
feeding strategy to enhance the alkaline NO
RR performance. Our platform achieves near-100% NH
Faradaic efficiency (pH = 14) with a current density of 2 A cm
and enables an over 99% NO
-to-NH
conversion efficiency. We also convert NO
to high-purity NH
Cl with near-unity efficiency, suggesting a practical approach to valorizing pollutants into valuable ammonia products. Theoretical simulations and in situ experiments reveal that Cl-coordination endows a shifted d-band center of Pd atoms to construct local H
-abundant environments, through arousing dangling O-H water dissociation and fast *H desorption, for *NO intermediate hydrogenation and finally effective NO
-to-NH
conversion.
The host immune response effecting on biomaterials is critical to determine implant fates and bone regeneration property. Bone marrow stem cells (BMSCs) derived exosomes (Exos) contain multiple ...biosignal molecules and have been demonstrated to exhibit immunomodulatory functions. Herein, we develop a BMSC-derived Exos–functionalized implant to accelerate bone integration by immunoregulation. BMSC-derived Exos were reversibly incorporated on tannic acid (TA) modified sulfonated polyetheretherketone (SPEEK) via the strong interaction of TA with biomacromolecules. The slowly released Exos from SPEEK can be phagocytosed by co-cultured cells, which could efficiently improve the biocompatibilities of SPEEK. In vitro results showed the Exos loaded SPEEK promoted macrophage M2 polarization via the NF-κB pathway to enhance BMSCs osteogenic differentiation. Further in vivo rat air-pouch model and rat femoral drilling model assessment of Exos loaded SPEEK revealed efficient macrophage M2 polarization, desirable new bone formation, and satisfactory osseointegration. Thus, BMSC-derived Exos–functionalized implant exerted osteoimmunomodulation effect to promote osteogenesis.
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•The implanted biomaterials as foreign substances trigger a cascade of immune responses.•BMSC-derived exosomes with immunomodulatory were suitable for bioactive coating to exert osteoimmunomodulation effect.•Exosome-functionalized SPEEK can modulate macrophages M2 polarization via NF‐κB pathway.•Exosome-functionalized SPEEK with osteoimmunomodulation properties can promote osseointegration.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A novel, label-free and inherent electroactive redox immunosensor for ultrasensitive detection of carcinoembryonic antigen (CEA) was proposed based on gold nanoparticles (AuNPs) and potassium ...ferricyanide-doped polyaniline (FC-PANI) nanoparticles. FC-PANI composite was synthesized via oxidative polymerization of aniline, using potassium ferricyanide (K3Fe(CN)6) as both oxidant and dopant. FC-PANI acting as the signal indicator was first fixed on a gold electrode (GE) to be the signal layer. Subsequently, the negatively charged AuNPs could be adsorbed on the positively charged FC-PANI modified GE surface by electrostatic adsorption, and then to immobilize CEA antibody (anti-CEA) for the assay of CEA. The CEA concentration was measured through the decrease of amperometric signals in the corresponding specific binding of antigen and antibody. The wide linear range of the immunosensor was from 1.0 pg mL(-1) to 500.0 ng mL(-1) with a low detection limit of 0.1 pg mL(-1) (S/N=3). The proposed method would have a potential application in clinical immunoassays with the properties of facile procedure, stability, high sensitivity and selectivity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Long noncoding RNA (lncRNAs) UCA1 has been known to be critical for the chondrogenic differentiation of marrow mesenchymal stem cells (MSCs). In this study, we explore the effects and mechanisms of ...UCA1 on the promotion of chondrogenesis of MSCs. During the processes of chondrogenic differentiation of MSCs, UCA1, miRNA-145-5p or miRNA-124-3p was overexpressed into MSCs. UCA1 substantially improved chondrogenesis of MSCs. Furthermore, UCA1 obviously down-regulated the expression of miRNA-145-5p and miRNA-124-3p, which attenuated the chondrogenic differentiation of MSCs. In addition, UCA1 significantly stimulated TGF-β pathway member SMAD5 and SMAD4, which is targeted by miRNA-145-5p and miRNA-124-3p. Collectively, these outcomes suggest that UCA1 enhances chondrogenic differentiation of MSCs via the miRNA-145-5p/SMAD5 and miRNA-124-3p/SMAD4 axis.
•UCA1 promoted the chondrogenic differentiation of MSCs.•UCA1 down-regulated miRNA-145-5p/miRNA-124-3p during this process.•miRNA-145-5p targeted SMAD5 and miRNA-124-3p targeted SMAD4.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Excessive consumption of fossil fuels gives rise to the increasing emission of carbon dioxide (CO2) in the atmosphere and furthers the ecocrisis. Electrochemical CO2 reduction (ECR) has both ...functions of dwindling greenhouse gas concentration and converting it into valuable products. Due to the intrinsic chemical inertness of CO2 molecules, the study on efficient and low‐cost catalysts has attracted much attention. Recently isolated atoms, dispersed in stable support, play an important role in decreasing energy barriers of intermediate steps and obtaining target products with high activity and selectivity for ECR. The effective regulation of central atoms or coordination environment is significant to realize the desired performances of ECR with a high efficiency and selectivity. Hence, a comprehensive summary about strategies for improving the performance of ECR on single atom catalysts (SACs) is necessary. Herein, the SACs on various supports are introduced, the methods to design stable SACs are discussed, and the strategies for tuning the performance of ECR on SACs are summarized. The localized environment manipulation is widely used for high‐performance SACs design, including regulating central atoms and coordination environment. Finally, the perspectives are discussed to shed light on the rational design of intriguing SACs for ECR.
The performance of single atom catalysts (SACs) in carbon dioxide (CO2) electroreduction is closely related to the central atoms and its coordination environment. Strategies which include regulating the central atoms, coordination atoms, coordination number, and diatomic strategies are successfully developed to enhance the performance of SACs in CO2 reduction reaction.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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