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1.
J Environ Manage ; 301: 113898, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34626943

RESUMO

In shallow eutrophic lakes, submersed macrophytes are essential for maintaining a clear water state, and they are affected markedly by fishes directly through herbivory and indirectly by fish-invertebrate-periphyton complexity, a pathway that presently is not well understood in subtropical lakes but probably vital to lake managements. We conducted a mesocosm study involving benthic fish (Misgurnus anguillicaudatus), snails (Radix swinhoei) and submersed macrophyte (Vallisneria natans), aiming to examine whether benthic fish is detrimental to reestablishment of clear-water macrophyte-dominated state in eutrophic degraded lakes. In addition, we aimed to investigate the cascading effect that benthic fish might have on periphyton and phytoplankton and to what extent snails can alleviate this effect. Our results showed that benthic fish promoted nutrient release from the sediment and thereby facilitated the growth of phytoplankton and periphyton, leading to reduced growth of submerged macrophytes due to shading. Snails consumed the periphyton attached on the leaves of macrophytes, thereby being beneficial to the plant growth, albeit it could not fully counteract the adverse effects from benthic fish. The water quality indicators in terms of nutrients concentrations, phytoplankton biomass and light extinction coefficient along the water column was affected primarily by benthic fish, followed by macrophytes and snails. To target a clear-water condition, the water quality was best at the presence of macrophytes alone or in combination with snails, and worst at the presence of benthic fish. Our results implied that the removal of benthic fish should be a useful ecological restoration method for rehabilitation of submersed macrophytes and water quality improvement in subtropic, eutrophic, shallow lakes following external nutrient loading reduction.


Assuntos
Hydrocharitaceae , Lagos , Animais , Biomassa , Peixes , Fósforo , Fitoplâncton
2.
J Hazard Mater ; 422: 126910, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34416700

RESUMO

Exploring the transport behaviors of thallium (Tl) in porous media is crucial for predicting Tl pollution in natural soils and groundwater. In recent years, the misuse of plastics has led to plastic becoming an emerging pollutant in soil. In this work, the effects of plastic particles on Tl(I) transport in water-saturated sand columns were investigated under different ionic strengths (ISs), pH values, and plastic particle sizes. The two-site nonequilibrium model was selected to fit the breakthrough curves (BTCs) of Tl(I). The results demonstrated that nanoplastics (NPs) accelerated Tl(I) transport at pH 7, which might be attributed to the competitive adsorption of NPs and Tl(I) on sand surfaces. However, at pH 5, the deposited NPs might provide more adsorption sites for Tl(I), and thus enhance its retention in the columns. In addition, the "straining" process could intercept microplastics (MPs) with Tl(I) that was attached under unfavorable attachment conditions, which would result in the inhibited mobility of Tl(I). On the other hand, the migration of plastics was restrained to some extent when Tl(I) was present. Overall, the findings from this work provided a new perspective for understanding the transport of Tl(I) and plastics in subsurface environments.

3.
Opt Lett ; 46(21): 5336-5339, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34724469

RESUMO

A low-dispersion mirror (LDM), an important component in ultrafast laser systems, requires both a broad low-dispersion laser-induced damage threshold (LIDT). It is difficult for a traditional quarter-wavelength-based dielectric LDM to achieve these characteristics at the same time. We propose a novel, to the best of our knowledge, low-dispersion mirror (NLDM) that combines periodic chirped layers at the top and alternating quarter-wavelength layers at the bottom. Low dispersion is achieved by introducing a large same group delay (GD) for different wavelengths, so the bandwidth is broadened greatly. In addition, owing to the staggered electric field intensity peak effect in the structure, the NLDM shows the potential for high laser damage resistance. The experiments demonstrated that the NLDM doubles the low-dispersion bandwidth, while the LIDT is also increased compared with the LDM. This novel concept results in improved performance and paves the way toward a new generation of the LDM for ultrafast bandwidth and a high laser applications.

4.
Environ Pollut ; 293: 118512, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34793902

RESUMO

Antibiotic resistance is a growing problem for ecosystem health and public healthcare. Hence, the transmission of antibiotic resistance from human and animal origins to natural environments requires careful investigation. In this study, nine antibiotic resistance genes (ARGs), three mobile genetic elements (MGEs), and their relations with antibiotics, heavy metals, and microbiota were investigated in 16 sample sites (Xinxiang, China). Fluoroquinolones (0.13-14.22 µg/L) were most abundant in hospital effluent and oxytetracycline (251.86-5817.47 µg/kg) in animal manure. Animal manure showed the highest levels of zinc (80.79-2597.14 mg/kg) and copper (32.47-85.22 mg/kg), possibly affecting the prevalence of intI1 and aac(6')-Ib genes. Aminoglycoside and sulfonamide resistance genes (aac(6')-Ib, aadA, and sul1) were the main ARGs in this area. In addition, the detected ARGs and MGEs were higher in animal manure than in hospital effluent, except for the sul1 gene. On the other hand, the incomplete removal of antibiotics (29.76-100%), heavy metals (31.25-100%), and ARGs (1-3 orders of magnitude) in MWWTPs resulted in the accumulation of these contaminants in the receiving river. Network analysis suggested that the potential hosts (Jeotgalibaca, Atopostipes, Corynebacterium_1, etc.) of ARGs were more predominant in animal manure rather than hospital effluent, indicating a higher ARG transfer potential in animal manure compared with hospital sources. These results provide useful insights into the different migration and dissemination routes of antibiotics, heavy metals, ARGs, and microbiota from anthropogenic and animal origins to their receiving environments via MWWTP discharge and manure fertilization.

5.
Int J Biol Sci ; 17(15): 4271-4284, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34803497

RESUMO

Mastitis causes great psychological and physical pain among women. Our previous studies found that niacin has anti-inflammatory effect, and the realization of this function depends on GPR109A. However, there are no previous reports about the anti-inflammatory function of GPR109A in mastitis. In our study, we observed the effect of niacin on the WT and GPR109A-/- mice mastitis model. The results showed that administration of niacin to WT mice reduced the damage, proinflammatory mediators and protected the integrity of the blood milk barrier in mammary gland. While in GPR109A-/- mice, there was no effect on the above indexes. In mammary epithelial cells, GPR109A was able to promote autophagy and Nrf2 nuclear import through AMPK. In LPS-induced mammary epithelial cells, niacin inhibited the LPS-induced inflammatory response and downregulation of tight junction proteins, and these effects were eliminated by knocking down GPR109A, blocking autophagy or inhibiting Nrf2 nuclear import. These results indicate that in mastitis, GPR109A promotes autophagy and Nrf2 nuclear import through AMPK, thereby inhibiting inflammatory damage to the mammary gland and repairing the blood milk barrier. Our results suggested that GPR109A may be a potential target for the treatment of mastitis.

6.
Mitochondrial DNA B Resour ; 6(12): 3398-3399, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34805516

RESUMO

Pseudorhaetus sinicus is a stag beetle common to China and Vietnam, but whose distribution is limited within China. Little is known about the molecular biological characteristics of this species, so we characterized its complete mitochondrial genome (GenBank accession number MZ504793.1). The mitogenome consists of a circular DNA molecule of 18,126 bp, with 67.693% AT content. It contains 13 protein-coding genes (PCGs), 22 tRNA genes, and two rRNA genes. The PCGs have typical ATN (Met) start codons and TAN stop codons. Phylogenetic analysis suggests that P. sinicus is closely related to Prosopocoilus confucius. This newly described mitochondrial genome provides a valuable resource for the phylogenetic analysis of Lucanidae beetles.

7.
Sci Rep ; 11(1): 22116, 2021 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-34764340

RESUMO

Recently, a great effort has been made to perfect the therapeutic effect of solid tumor, from single-agent therapy to combined therapy and many other polymer-drug conjugations with dual or more anticancer agents due to their promising synergistic effect and higher drug level accumulation towards tumor tissues. Different polymer-drug spacers present diverse therapeutic efficacy, therefore, finding an appropriate spacer is desirable. In this study, dual drugs that are doxorubicin (DOX) and mitomycin C (MMC) were conjugated onto a polymer carrier (xyloglucan) via various peptide or amide bonds, and a series of polymers drug conjugates were synthesized with different spacers and their effect on tumor treatment efficacy was studied both in vitro and in vivo. The result shows that the synergistic effect is better when using different linker to conjugate different drugs rather than using the same spacer to conjugate different drugs on the carrier. Particularly, the finding of this works suggested that, using peptide bond for MMC and amide bond for DOX to conjugate dual drugs onto single XG carrier could improve therapeutic effect and synergy effect. Therefore, in polymer-pharmaceutical formulations, the use of different spacers to optimize the design of existing drugs to enhance therapeutic effects is a promising strategy.

8.
Artigo em Inglês | MEDLINE | ID: mdl-34802141

RESUMO

OBJECTIVE: To explore inheritance of the m.3697G > A mitochondrial DNA (mtDNA) mutation and the effectiveness of preimplantation genetic diagnosis (PGD) for the carrier. METHODS: The study encompassed a pedigree of m.3697G > A mtDNA mutation, including one asymptomatic patient who pursued for PGD treatment. Twelve cumulus oocyte complexes (COCs) were collected in the first PGD cycle and 11 COCs in the second cycle. The efficiency of cumulus cells, polar bodies, and trophectoderm (TE) in predicting the m.3697G > A heteroplasmy of embryos was analyzed. RESULTS: From 23 COCs, 20 oocytes were fertilized successfully. On day 5 and 6 post-fertilization, 15 blastocysts were biopsied. The m.3697G > A mutation load of TE biopsies ranged from 15.2 to 100%. In the first cycle, a blastocyst with mutation load of 31.7% and chromosomal mosaicism was transferred, but failed to yield a clinical pregnancy. In the second cycle, a euploid blastocyst with mutation load of 53.9% was transferred, which gave rise to a clinical pregnancy. However, the pregnancy was terminated due to fetal cleft lip and palate. The mutation loads of different tissues (47.7 ± 1.8%) from the induced fetus were comparable to that of the biopsied TE and amniotic fluid cell (49.7%). The mutation load of neither cumulus cells (R2 = 0.02, p = 0.58) nor polar bodies (R2 = 0.33, p = 0.13) correlated with TE mutation load which was regarded as a gold standard. CONCLUSIONS: The m.3697G > A mutation showed a random pattern of inheritance. PGD could be used to reduce the risk of inheritance of a high mutation load. Cumulus cells are not a suitable predictor of blastocyst mutation load.

10.
DNA Cell Biol ; 2021 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-34762509

RESUMO

Prognostic signatures of specific immune-related long noncoding RNAs (irlncRNAs) have been elucidated with the development of immunotherapy for breast cancer, but the heterogeneity of gene expression in different patients still limits their effectiveness. We constructed a new prognostic signature based on the relative expression of differentially expressed irlncRNA (DEirlncRNA) pairs and analyzed its clinical application in 1069 patients from The Cancer Genome Atlas-Breast Cancer (TCGA-BRCA) containing 745 White patients, 180 Black and African American patients, 58 Asian patients, 181 stage I patients, 606 stage II patients, 240 stage III patients, and 20 stage IV patients. Data from TCGA-BRCA and ImmPort were used to screen DEirlncRNAs, and the DEirlncRNA pairs were established by cyclical single comparison of each DEirlncRNA. After the data optimization, we constructed a signature containing 24 DEirlncRNA pairs. Risk groups of this signature were defined using the cutoff value from the 10-year survival receiver operating characteristic curve, and Kaplan-Meier analysis verified its prognostic effectiveness. Furthermore, we confirmed this signature as an independent prognostic factor and confirmed its close association with traditional clinicopathological factors. Moreover, this risk signature was closely related to tumor-infiltrating immune cells and drug susceptibility. In short, we successfully constructed a risk signature of DEirlncRNA pairs, which might provide new insights for breast cancer precision therapy.

11.
Circ Res ; 2021 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-34763521

RESUMO

Background: Acute myocardial infarction (AMI) patients suffer systemic metabolic dysfunction via incompletely understood mechanisms. Adipocytes play critical role in metabolic homeostasis. The impact of AMI upon adipocyte function is unclear. Small extracellular vesicles (sEV) critically contribute to organ-organ communication. Whether and how sEV mediate post-MI cardiomyocyte/adipocyte communication remain unknown.Methods Plasma sEV were isolated from sham control (Pla-sEVSham) or 3 hours after myocardial ischemia/reperfusion (Pla-sEVMI/R) and incubated with adipocytes for 24 hours. Compared to Pla-sEVSham, Pla-sEVMI/R significantly altered expression of genes known to be important in adipocyte function, including a well-known metabolic regulatory/cardioprotective adipokine, adiponectin (APN). Pla-sEVMI/R activated two (PERK-CHOP and ATF6-EDEM pathways) of the three endoplasmic reticulum (ER) stress pathways in adipocytes. These pathological alterations were also observed in adipocytes treated with sEVs isolated from adult cardiomyocytes subjected to in vivo MI/R (Myo-sEVMI/R). Bioinformatic/RT-qPCR analysis demonstrates that the members of miR-23-27-24 cluster are significantly increased in Pla-sEVMI/R, Myo-sEVMI/R, and adipose tissue of MI/R animals. Administration of cardiomyocyte-specific miR-23-27-24 sponges abolished adipocyte miR-23-27-24 elevation in MI/R animals, supporting the cardiomyocyte origin of adipocyte miR-23-27-24 cluster. In similar fashion to Myo-sEVMI/R, a miR-27a mimic activated PERK-CHOP and ATF6-EDEM mediated ER stress. Conversely, a miR-27a inhibitor significantly attenuated Myo-sEVMI/R-induced ER stress and restored APN production. Results: An unbiased approach identified EDEM3 as a novel downstream target of miR-27a. Adipocyte EDEM3 deficiency phenocopied multiple pathological alterations caused by Myo-sEVMI/R, whereas EDEM3 overexpression attenuated Myo-sEVMI/R-resulted ER stress. Finally, administration of GW4869 or cardiomyocyte-specific miR-23-27-24 cluster sponges attenuated adipocyte ER stress, improved adipocyte endocrine function, and restored plasma APN levels in MI/R animals. Conclusion: We demonstrate for the first time that MI/R causes significant adipocyte ER stress and endocrine dysfunction by releasing miR-23-27-24 cluster-enriched sEV. Targeting sEV-mediated cardiomyocyte-adipocyte pathologic communication may be of therapeutic potential to prevent metabolic dysfunction after MI/R.

12.
J Zhejiang Univ Sci B ; 22(11): 929-940, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34783223

RESUMO

Inflammation plays an important role in the development of acute lung injury (ALI). Severe pulmonary inflammation can cause acute respiratory distress syndrome (ARDS) or even death. Expression of proinflammatory interleukin-|1ß (IL-|1ß) and inducible nitric oxide synthase (iNOS) in the process of pulmonary inflammation will further exacerbate the severity of ALI. The purpose of this study was to explore the effect of Palrnatine (Pa) on lipopolysaccharide (LPS)-induced mouse ALI and its underlying mechanism. Pa, a natural product, has a wide range of pharmacological activities with the potential to protect against lung injury. Western blotting and quantitative real-time polymerase chain reaction (qRT-PCR) assays were performed to detect the expression and translation of inflammatory genes and proteins in vitro and in vivo. Immunoprecipitation was used to detect the degree of P65 translocation into the nucleus. We also used molecular modeling to further clarify the mechanism of action. The results showed that Pa pretreatment could significantly inhibit the expression and secretion of the inflammatory cytokine IL-1ß, and significantly reduce the protein level of the proinflammatory protease iNOS, in both in vivo and in vitro models induced by LPS. Further mechanism studies showed that Pa could significantly inhibit the activation of the protein kinase B (Akt)/nuclear factor-κB (NF-κB) signaling pathway in the LPS-induced ALI mode and in LPS-induced RAW264.7 cells. Through molecular dynamics simulation, we observed that Pa was bound to the catalytic pocket of Akt and effectively inhibited the biological activity of Akt. These results indicated that Pa significantly relieves LPS-induced ALI by activating the Akt/NF-κB signaling pathway.

13.
J Biol Chem ; : 101398, 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34774525

RESUMO

Many studies have confirmed the enzymatic activity of a mammalian phosphatidylcholine phospholipase C (PC-PLC), which produces diacylglycerol (DAG) and phosphocholine through the hydrolysis of phosphatidylcholine (PC) in the absence of ceramide. However, the protein(s) responsible for this activity have never yet been isolated. Based on the fact that tricyclodecan-9-yl-potassium xanthate (D609) can inhibit both PC-PLC and sphingomyelin synthase (SMS) activities, and SMS1 and SMS2 have a conserved catalytic domain which could mediates a nucleophilic attack on the phosphodiester bond of PC, we hypothesized that both SMS1 and SMS2 might have PC-PLC activity. In the current study, we found that purified recombinant SMS1 and SMS2 but not SMSr (sphingomyelin synthase related protein) have PC-PLC activity. Moreover, we prepared liver-specific Sms1/global Sms2 double knockout (dKO) mice. We found that liver PC-PLC activity was significantly reduced and steady state levels of PC and DAG in the liver were regulated by the deficiency, in comparison with control mice. Using adenovirus, we expressed Sms1 and Sms2 genes in the liver of the dKO mice, respectively, and found that expressed SMS1 and SMS2 can hydrolyze PC to produce DAG and phosphocholine. Thus, SMS1 and SMS2 exhibit PC-PLC activity in vitro and in vivo.

14.
Artigo em Inglês | MEDLINE | ID: mdl-34637608

RESUMO

Rivaroxaban is a direct factor Xa inhibitor used for the management of thromboembolic disorders. The aim of this study was to evaluate the safety, pharmacokinetic profile, and bioequivalence of a generic and a branded rivaroxaban formulation (Xarelto) under fasted and fed conditions in healthy Chinese volunteers. An open-label, randomized, single-dose, 4-period complete, and replicate crossover study in healthy Chinese volunteers was performed. A single oral dose of 20 mg of 2 rivaroxaban formulations was administered to 72 healthy volunteers, with 36 in the fasted group and 36 consuming a high-fat diet. The evaluated pharmacokinetic parameters, including maximum rivaroxaban concentration, the area under the concentration-time curve (AUC) from time 0 to the last measurable concentration, and AUC from time 0 to infinity, were assessed for BE. The plasma concentrations of rivaroxaban were measured by a validated liquid chromatography-tandem mass spectrometry method. The geometric mean ratios with 90% confidence intervals of the maximum rivaroxaban concentration, AUC from time 0 to the last measurable concentration, and AUC from time 0 to infinity were all within the range of 80% to 125% under fasted and fed conditions. The within-subject variability of the test and reference products was compared, and the upper limit of the 90% confidence intervals for the test-to-reference ratio of the within-subject variability was <2.5, which indicated that the rivaroxaban test and the rivaroxaban reference formulation were bioequivalent. No serious adverse events were reported during either fasted or fed conditions of the study.

15.
Antioxidants (Basel) ; 10(10)2021 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-34679768

RESUMO

The genus Lilium contains more than 100 wild species and numerous hybrid varieties. Some species of them have been used as medicine and food since ancient times. However, the research on the active components and the medical properties of lilies has only focused on a few species. In this study, the total phenolic acid content (TPC), total flavonoid content (TFC), and antioxidant capacity of 22 representative lilies were systematically investigated. The results showed that the TPC, TFC and antioxidant activity were highly variable among different lilies, but they were significantly positively correlated. Hierarchical cluster analysis indicated that L. henryi and L. regale were arranged in one group characterized by the highest TPC, TFC and antioxidant capacity, followed by Oriental hybrids and Trumpet and Oriental hybrids. The traditional edible and medicinal lilies were clustered in low TPC, TFC and antioxidant capacity group. A total of 577 secondary metabolites, including 201 flavonoids, 153 phenolic acids, were identified in the five species with great differences in antioxidant capacity by extensive targeted metabonomics. Differentially accumulated metabolites (DAMs) analysis reviewed that the DAMs were mainly enriched in secondary metabolic pathways such as isoflavonoid, folate, flavonoid, flavone, flavonol, phenylpropanoid, isoquinoline alkaloid biosynthesis, nicotinate and nicotinamide metabolism and so on. Correlation analysis identified that 64 metabolites were significantly positively correlated with antioxidant capacity (r ≥ 0.9 and p < 0.0001). These results suggested that the genus Lilium has great biodiversity in bioactive components. The data obtained greatly expand our knowledge of the bioactive constituents of Lilium spp. Additionally, it also highlights the potential application of Lilium plants as antioxidants, functional ingredients, cosmetic products and nutraceuticals.

16.
Resuscitation ; 2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34624410

RESUMO

OBJECTIVE: This study aimed to investigate the predictive value of pulse oximetry plethysmography (POP) for the return of spontaneous circulation (ROSC) in cardiac arrest (CA) patients. METHODS: This was a multicenter, observational, prospective cohort study of patients hospitalized with cardiac arrest at 14 teaching hospitals cross China from December 2013 through November 2014. The study endpoint was ROSC, defined as the restoration of a palpable pulse and an autonomous cardiac rhythm lasting for at least 20 minutes after the completion or cessation of CPR. RESULTS: 150 out-of-hospital cardiac arrest (OHCA) patients and 291 in-hospital cardiac arrest (IHCA) patients were enrolled prospectively. ROSC was achieved in 20 (13.3%) and 64 (22.0%) patients in these cohorts, respectively. In patients with complete end-tidal carbon dioxide (ETCO2) and POP data, patients with ROSC had significantly higher levels of POP area under the curve (AUCp), wave amplitude (Amp) and ETCO2 level during CPR than those without ROSC (all p < 0.05). Pairwise comparison of receiver operating characteristic (ROC) curve analysis indicated no significant difference was observed between ETCO2 and Amp (p = 0.204) or AUCp (p = 0.588) during the first two minutes of resuscitation. CONCLUSION: POP may be a novel and effective method for predicting ROSC during resuscitation, with a prognostic value similar to ETCO2 at early stage.

17.
Tree Physiol ; 2021 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-34718811

RESUMO

Quantifying inter-specific variations of tree resilience to drought and revealing the underlying mechanisms are of great importance to the understanding of forest functionality particularly in water-limited regions. So far, comprehensive studies incorporating investigations in inter-specific variations of long-term growth patterns of trees and the underlying physiological mechanisms are very limited. Here, in a semi-arid site of northern China, tree radial growth rate, inter-annual tree-ring growth responses to climate variability, as well as physiological characteristics pertinent to xylem hydraulics, carbon assimilation and drought tolerance were analyzed in seven pine species growing in a common environment. Considerable inter-specific variations in radial growth rate, growth response to drought and physiological characteristics were observed among the studied species. Differently, the studied species exhibited similar degrees of resistance to drought-induced branch xylem embolism with water potential corresponding to 50% loss hydraulic conductivity ranged from -2.31 to -2.96 MPa. We found that higher branch hydraulic efficiency is related to greater leaf photosynthetic capacity, smaller hydraulic safety margin and lower woody density (P < 0.05, linear regressions) but not related to higher tree radial growth rate (P > 0.05). Rather, species with higher hydraulic conductivity and photosynthetic capacity was more sensitive to drought stress and tended to show weaker growth resistance to extreme drought events as quantified by tree-ring analyses, which is at least partially due to a trade-off between hydraulic efficiency and safety across species. This study thus demonstrates the importance of drought resilience rather than instantaneous water and carbon flux capacity in determining tree growth in water-limited environments.

19.
Nanoscale ; 13(40): 16986-16994, 2021 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-34613321

RESUMO

Coupled with renewable electricity, electrochemical reduction of CO2 (CO2RR) is one of the sustainable strategies for the production of value-added carbon-containing chemicals. Cu-based catalysts are by far the most widely studied electrocatalytic materials for CO2RR, although they exhibit poor performance in CO selectivity. In this work, we have designed a Cu1.96S/Cu tandem structure via a combined electrospinning and calcination method. The catalyst enables CO2 reduction to CO with high selectivity >80% with a production rate of 34.6 µmol h-1 cm-2 at -0.68 V vs. RHE, which is superior to most of the Cu-based catalysts under the same operation conditions. Theoretical simulations show that the improved CO2RR performance stems from the Cu1.96S/Cu tandem structure in which Cu acts as a *CO-producing site and the neighboring Cu1.96S facilitates the following *CO desorption step. This work opens new possibilities for exploiting tandem catalysis mechanisms.

20.
J Am Chem Soc ; 143(42): 17517-17525, 2021 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-34647722

RESUMO

Controlling oxygen deficiencies is essential for the development of novel chemical and physical properties such as high-Tc superconductivity and low-dimensional magnetic phenomena. Among reduction methods, topochemical reactions using metal hydrides (e.g., CaH2) are known as the most powerful method to obtain highly reduced oxides including Nd0.8Sr0.2NiO2 superconductor, though there are some limitations such as competition with oxyhydrides. Here we demonstrate that electrochemical protonation combined with thermal dehydration can yield highly reduced oxides: SrCoO2.5 thin films are converted to SrCoO2 by dehydration of HSrCoO2.5 at 350 °C. SrCoO2 forms square (or four-legged) spin tubes composed of tetrahedra, in contrast to the conventional infinite-layer structure. Detailed analyses suggest the importance of the destabilization of the SrCoO2.5 precursor by electrochemical protonation that can greatly alter reaction energy landscape and its gradual dehydration (H1-xSrCoO2.5-x/2) for the SrCoO2 formation. Given the applicability of electrochemical protonation to a variety of transition metal oxides, this simple process widens possibilities to explore novel functional oxides.

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