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It is crucial to achieve continuous production of highly concentrated and pure C2 chemicals through the electrochemical CO2 reduction reaction (eCO2RR) for artificial carbon cycling, yet it has remained unattainable until now. Despite one-pot tandem catalysis (dividing the eCO2RR to C2 into two catalytical reactions of CO2 to CO and CO to C2) offering the potential for significantly enhancing reaction efficiency, its mechanism remains unclear and its performance is unsatisfactory. Herein, we selected different CO2-to-CO catalysts and CO-to-acetate catalysts to construct several tandem catalytic systems for the eCO2RR to acetic acid. Among them, a tandem catalytic system comprising a covalent organic framework (PcNi-DMTP) and a metal-organic framework (MAF-2) as CO2-to-CO and CO-to-acetate catalysts, respectively, exhibited a faradaic efficiency of 51.2% with a current density of 410 mA cm-2 and an ultrahigh acetate yield rate of 2.72 mmol m-2 s-1 under neutral conditions. After electrolysis for 200 h, 1 cm-2 working electrode can continuously produce 20 mM acetic acid aqueous solution with a relative purity of 95+%. Comprehensive studies revealed that the performance of tandem catalysts is influenced not only by the CO supply-demand relationship and electron competition between the two catalytic processes in the one-pot tandem system but also by the performance of the CO-to-C2 catalyst under diluted CO conditions.
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It is a very important but still challenging task to develop bifunctional electrocatalysts for highly efficient CO2 overall splitting. Herein, we report a stable metal-organic framework (denoted as PcNi-Co-O), composed of (2,3,9,10,16,17,23,24-octahydroxyphthalocyaninato)nickel(II) (PcNi-(O-)8) ligands and the planar CoO4 nodes, for CO2 overall splitting. When working as both cathode and anode catalysts (i.e., PcNi-Co-O||PcNi-Co-O), PcNi-Co-O achieved a commercial-scale current density of 123 mA cm-2 (much higher than the reported values (0.2-12 mA cm-2)) with a Faradic efficiency (CO) of 98% at a low cell voltage of 4.4 V. Mechanism studies suggested the synergistic effects between two active sites, namely, (i) electron transfer from CoO4 to PcNi sites under electric fields, resulting in the raised oxidizability/reducibility of CoO4/PcNi sites, respectively; (ii) the energy-level matching of cathode and anode catalysts can reduce the energy barrier of electron transfer between them and improve the performance of CO2 overall splitting.
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BACKGROUND: Circulating zinc (Zn) concentrations are lower than normal in patients with Parkinson disease (PD). It is unknown whether Zn deficiency increases the susceptibility to PD. OBJECTIVES: The study aimed to investigate the effect of dietary Zn deficiency on behaviors and dopaminergic neurons in a mouse model of PD and to explore potential mechanisms. METHODS: Male C57BL/6J mice aged 8-10 wk were fed Zn adequate (ZnA; 30 µg/g) or Zn deficient (ZnD; <5 µg/g) diet throughout the experiments. Six weeks later 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) was injected to generate the PD model. Controls were injected with saline. Thus, 4 groups (Saline-ZnA, Saline-ZnD, MPTP-ZnA, and MPTP-ZnD) were formed. The experiment lasted 13 wk. Open field test, rotarod test, immunohistochemistry, and RNA sequencing were performed. Data were analyzed with t-test, 2-factor ANOVA, or Kruskal-Wallis test. RESULTS: Both MPTP and ZnD diet treatments led to a significant reduction in blood Zn concentrations (PMPTP = 0.012, PZn = 0.014), reduced total distance traveled (PMPTP < 0.001, PZn = 0.031), and affected the degeneration of dopaminergic neurons in the substantia nigra (PMPTP < 0.001, PZn = 0.020). In the MPTP-treated mice, the ZnD diet significantly reduced total distance traveled by 22.4% (P = 0.026), decreased latency to fall by 49.9% (P = 0.026), and reduced dopaminergic neurons by 59.3% (P = 0.002) compared with the ZnA diet. RNA sequencing analysis revealed a total of 301 differentially expressed genes (156 upregulated; 145 downregulated) in the substantia nigra of ZnD mice compared with ZnA mice. The genes were involved in a number of processes, including protein degradation, mitochondria integrity, and α-synuclein aggregation. CONCLUSIONS: Zn deficiency aggravates movement disorders in PD mice. Our results support previous clinical observations and suggest that appropriate Zn supplementation may be beneficial for PD.
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Desnutrição , Doença de Parkinson , Camundongos , Masculino , Animais , Doença de Parkinson/metabolismo , Neurônios Dopaminérgicos/metabolismo , Camundongos Endogâmicos C57BL , Dieta , Dopamina/metabolismo , Zinco , Substância Negra/metabolismo , Modelos Animais de Doenças , 1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina/metabolismo , 1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina/farmacologiaRESUMO
A Gram-stain-negative, rod-shaped, glide, non-flagellated, and facultatively anaerobic bacterial strain, designated as Z654T, was isolated from the gut of abalone Haliotis discus hannai from Rongcheng, Shandong province, China. Cells are 0.2-0.8 µm in width and 0.7-3.4 µm in length. Cells grew best at 30 °C (range, 15-37 °C), pH 7.0 (range, 6.0-8.5) and NaCl concentration of 2.0% (w/v) (range, 1-10%). According to the phylogenetic analysis of 16S rRNA gene sequence, the strain belongs to the genus Halocynthiibacter and the closest strain is Halocynthiibacter arcticus KCTC 42129 T (97.12%). The genome size of strain Z654T was 3,296,250 bp and the DNA G + C content was 54.2 mol%. The average nucleotide identity (ANI) scores and digital DNA-DNA hybridization (dDDH) scores with H. arcticus KCTC 42129 T were 70% and 14.6-18.2%, respectively. The predominant quinone was Q-10 and the major fatty acids were C18:0, C18:1 ω7c 11-methyl and summed feature 8. The polar lipids consisted of phosphatidylcholine, phosphatidylglycerol, unidentified aminolipid and unidentifed lipids. Based on the phenotypic, phylogenetic and chemotaxonomic data, strain Z654T was considered to represent a novel species of the genus Halocynthiibacter, for which the name Halocynthiibacte halioticoli sp. nov., is proposed. The type strain is Z654T (= MCCC 1H00503T = KCTC 92003 T).
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Gastrópodes , Vísceras , Animais , Filogenia , RNA Ribossômico 16S/genética , DNA Bacteriano/genética , Ácidos Graxos/química , Gastrópodes/microbiologia , Análise de Sequência de DNA , Técnicas de Tipagem Bacteriana , Fosfolipídeos/química , Ubiquinona/químicaRESUMO
A Gram-stain-negative, rod-shaped, non-gliding, non-flagellated, yellow, facultatively aerobic bacterial strain, designated as W260T, was isolated from marine sediment of Xiaoshi Island, Weihai, PR China. The cells of W260T were 0.3-0.5 µm wide and 1.5-2.0 µm long. Strain W260T grows optimally at a temperature of 33â°C (range, 15-37â°C), pH 8 (range, pH 6.5-9.5) and witha NaCl concentration of 3.0â% (w/v; range, 1-8â%). It has the highest sequence similarity to Thiohalobacter thiocyanaticus DSM 21152T (91.7â%), followed by Wenzhouxiangella marina MCCC 1K00261T (91.4â%) and Thiohalospira alkaliphila DSM 17116T (90.7â%). The similarity between strain W260T and the species Thiohalophilus thiocyanatoxydans DSM 16326T was 89.4â%. Genome sequencing revealed a genome size of 3â430â000 bp and a DNA G+C content of 64.5âmol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain W260T and W. marina MCCC 1K00261T were 69.6 and 16.1-20.6â%, respectively. The predominant quinone was ubiquitin-8, and the major fatty acids were iso-C14â:â0 and iso-C16â:â0. The polar lipids consisted of phosphatidylethanolamine, phospholipid, phosphatidylglycerol, diphosphatidylglycerol and four unidentified lipids. Based on phenotypic, phylogenetic and chemotaxonomic information, it was determined that strain W260T represents a novel genus and species and it was given the name Marinihelvus fidelis sp. nov. The type strain is W260T (=MCCC 1H00471T=KCTC 92639T).
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Ácidos Graxos , Sedimentos Geológicos , Ácidos Graxos/química , Filogenia , Análise de Sequência de DNA , Composição de Bases , Técnicas de Tipagem Bacteriana , RNA Ribossômico 16S/genética , DNA Bacteriano/genética , Sedimentos Geológicos/microbiologia , Fosfolipídeos/química , GenômicaRESUMO
Two novel Gram-stain-negative, facultative anaerobic, chemoheterotrophic, non-motile and rod-shaped strains were isolated from intertidal sediment sampled at Xiaoshi Island, Weihai, PR China. Full sequence analysis of the 16S rRNA genes showed that the two strains were closely related to members of the genus Winogradskyella and the phylogenetic similarities to their closest relative, Winogradskyella aquimaris, were 96.7 and 95.8â%, respectively. The DNA G+C contents of strains 2Y89T and D23T were 33.3 and 35.1 mol%, respectively. The respiratory quinone detected in both strains was MK-6. The major fatty acids detected in strain 2Y89T were iso-C15â:â0 and iso-C15â:â1G, and in strain D23T they were iso-C15â:â1G, iso-C15â:â0 and iso-C17â:â03-OH. The principal polar lipids of strain 2Y89T mainly included phosphatidylethanolamine, aminoglycolipids, unidentified aminolipids, unidentified glycolipids and unidentified lipids; strain D23T was the same as strain 2Y89T except that it did not contain aminoglycolipids. Based on the phenotypic, chemical taxonomic, genotypic and phylogenetic features established in this study, we suggest that the new strains represent two novel species of the genus Winogradskyella, for which the names Winogradskyella vincentii sp. nov. (type strain 2Y89T=MCCC 1H00477T=KCTC 92034T) and Winogradskyella alexanderae sp. nov. (type strain D23T=MCCC 1H00462T=KCTC 92023T) are proposed.
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Bactérias , Ácidos Graxos , Filogenia , RNA Ribossômico 16S/genética , Composição de Bases , Ácidos Graxos/química , Análise de Sequência de DNA , DNA Bacteriano/genética , Técnicas de Tipagem BacterianaRESUMO
Cognitive deficit is a common comorbidity in temporal lobe epilepsy (TLE) and is not well controlled by current therapeutics. How epileptic seizure affects cognitive performance remains largely unclear. In this study we investigated the role of subicular seizure-activated neurons in cognitive impairment in TLE. A bipolar electrode was implanted into hippocampal CA3 in male mice for kindling stimulation and EEG recording; a special promoter with enhanced synaptic activity-responsive element (E-SARE) was used to label seizure-activated neurons in the subiculum; the activity of subicular seizure-activated neurons was manipulated using chemogenetic approach; cognitive function was assessed in object location memory (OLM) and novel object recognition (NOR) tasks. We showed that chemogenetic inhibition of subicular seizure-activated neurons (mainly CaMKIIα+ glutamatergic neurons) alleviated seizure generalization and improved cognitive performance, but inhibition of seizure-activated GABAergic interneurons had no effect on seizure and cognition. For comparison, inhibition of the whole subicular CaMKIIα+ neuron impaired cognitive function in naïve mice in basal condition. Notably, chemogenetic inhibition of subicular seizure-activated neurons enhanced the recruitment of cognition-responsive c-fos+ neurons via increasing neural excitability during cognition tasks. Our results demonstrate that subicular seizure-activated neurons contribute to cognitive impairment in TLE, suggesting seizure-activated neurons as the potential therapeutic target to alleviate cognitive impairment in TLE.
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Disfunção Cognitiva , Epilepsia do Lobo Temporal , Masculino , Camundongos , Animais , Convulsões , Neurônios , Epilepsia do Lobo Temporal/psicologia , Hipocampo , CogniçãoRESUMO
A novel Gram-stain-negative, aerobic, non-motile, rod-shaped and orange-colored bacterium, designated as strain C305T, was isolated from marine sediment of the coast area of Weihai, China. Strain C305T growth occurs at 4-40 °C (optimally at 30-33 °C), pH 6.0-9.0 (optimally at pH 8.0) and with 0.5-10.0% (w/v) NaCl (optimum 1.5-3.0%). No growth is observed without NaCl. The major cellular fatty acids of strain C305T were identified as iso-C15:0, iso-C15:1G and iso-C17:0 3-OH. The major respiratory quinone was found to be MK-6, and the DNA G + C content was determined to be 35.5 mol%. The predominant polar lipids were mainly phosphatidylethanolamines (PE), unidentified aminophospholipids (APL), andunidentified lipid (L2). Phylogenetic analysis based on 16S rRNA gene sequences revealed that C305T was a member of the genus Brumimicrobium and had a 16S rRNA gene sequence similarity values of 96.9-98.0% with recognized Brumimicrobium species. On the basis of the phylogenetic and phenotypic evidences, strain C305T represents a novel species of the genus Brumimicrobium, for which the name Brumimicrobium oceani sp. nov. is proposed. The type strain is C305T (= KCTC 62371 T = MCCC 1H00297T).
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Flavobacteriaceae , Água do Mar , Água do Mar/microbiologia , Filogenia , RNA Ribossômico 16S/genética , Cloreto de Sódio , Lagos , DNA Bacteriano/genética , Técnicas de Tipagem Bacteriana , Análise de Sequência de DNA , Vitamina K 2/química , Ácidos Graxos/análiseRESUMO
The effective detection of environmental pollutants is very important to the sustainable development of human health and the environment. A luminescent Cd(II) coordination complex, {[Cd(dbtdb)(1,2,4-H3btc)]·0.5H2O}n (1) (dbtdb = 1-(2,3,5,6-tetramethyl-4-((2-(thiazol-4-yl)-2H-benzo[d]imidazol-3(3aH)-yl)methyl)benzyl)-2,7a-dihydro-2-(thiazol-4-yl)-1H-benzo[d]imidazole, 1,2,4-H3btc = 1,2,4-benzenetricarboxylic acid), was obtained by hydrothermal reactions. Complex 1 has a chain structure decorated with uncoordinated Lewis basic O and S donors and provides good sensing of Fe3+, Cr2O72-, and p-nitrophenol with fluorescence quenching through an energy transfer process. The calculated binding constants were 3.3 × 103 mol-1 for Fe3+, 2.36 × 104 mol-1 for Cr2O72-, and 9.3 × 103 mol-1 for p-nitrophenol, respectively. These results show that 1 is a rare multiresponsive sensory material for efficient detection of Fe3+, Cr2O72-, and p-nitrophenol.
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Cádmio , Nitrofenóis , Humanos , Fluorescência , LuminescênciaRESUMO
Solvent effect plays an important role in catalytic reaction, but there is little research and attention on it in electrochemical CO2 reduction reaction (eCO2 RR). Herein, we report a stable covalent-organic framework (denoted as PcNi-im) with imidazole groups as a new electrocatalyst for eCO2 RR to CO. Interestingly, compared with neutral conditions, PcNi-im not only showed high Faraday efficiency of CO product (≈100 %) under acidic conditions (pH ≈ 1), but also the partial current density was increased from 258 to 320â mA cm-2 . No obvious degradation was observed over 10â hours of continuous operation at the current density of 250â mA cm-2 . The mechanism study shows that the imidazole group on the framework can be protonated to form an imidazole cation in acidic media, hence reducing the surface work function and charge density of the active metal center. As a result, CO poisoning effect is weakened and the key intermediate *COOH is also stabilized, thus accelerating the catalytic reaction rate.
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Ribosome assembly factors guide the complex process by which ribosomal proteins and the ribosomal RNAs form a functional ribosome. However, the assembly of plant plastid ribosomes is poorly understood. In the present study, we discovered a maize (Zea mays) plastid ribosome assembly factor based on our characterization of the embryo defective 15 (emb15) mutant. Loss of function of Emb15 retards embryo development at an early stage, but does not substantially affect the endosperm, and causes an albino phenotype in other genetic backgrounds. EMB15 localizes to plastids and possesses a ribosome maturation factor M (RimM) domain in the N-terminus and a predicted UDP-GlcNAc pyrophosphorylase domain in the C-terminus. The EMB15 RimM domain originated in bacteria and the UDP-GlcNAc pyrophosphorylase domain originated in fungi; these two domains came together in the ancestor of land plants during evolution. The N-terminus of EMB15 complemented the growth defect of an Escherichia coli strain with a RimM deletion and rescued the albino phenotype of emb15 homozygous mutants. The RimM domain mediates the interaction between EMB15 and the plastid ribosomal protein PRPS19. Plastid 16S rRNA maturation is also significantly impaired in emb15. These observations suggest that EMB15 functions in maize seed development as a plastid ribosome assembly factor, and the C-terminal domain is not important under normal conditions.
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Proteínas de Plantas/metabolismo , Plastídeos/metabolismo , Ribossomos/metabolismo , Sementes/metabolismo , Zea mays/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Proteínas de Plantas/genética , Plastídeos/genética , Ribossomos/genética , Sementes/genética , Zea mays/genéticaRESUMO
BACKGROUND: Benzo [a] pyrene (BaP), a potent carcinogen, has been proved that it has toxicological effects via activation the aryl hydrocarbon receptor (AhR) pathway. AhR can participate in regulating lipogenesis and lipolysis. This topic will verify whether BaP regulates lipid metabolism via AhR. METHODS: (1) C57BL/6 mice were gavaged with BaP for 12 weeks to detect serum lipids, glucose tolerance, and insulin resistance. Morphological changes in white adipose tissue (WAT) were detected by Hematoxylin and Eosin staining. The mRNA expression levels of adipogenesis-related factors included recombinant human CCAAT/enhancer binding protein alpha (C/EBPα), peroxisome proliferator-activated receptor gamma (PPARγ), and fatty acid binding protein 4 (FABP4) and inflammatory factors included nuclear factor kappa-B (NF-κB), monocyte chemotactic protein-1 (MCP-1), and tumor necrosis factor alpha (TNF-α) were detected using PCR. (2) Neutral lipid content changes in differentiated 3 T3-L1 adipocytes treated with BaP with and w/o AhR inhibitor were detected by Oil red staining. The protein expression levels of adipogenesis- and decomposition-related factors included PPARγ coactivator-1 alpha (PGC-1α), and peroxisome proliferation-activated receptor alpha (PPARα) were detected using western blotting. The mRNA expression levels of inflammatory factors were detected using PCR. RESULTS: (1) BaP inhibited body weight gain, decreased lipid content, increased lipid levels, and decreased glucose tolerance and insulin tolerance in mice; (2) BaP reduced the expressions of C/EBPα, PPARγ, FABP4, PGC-1α, and PPARα and increased the expressions of NF-κB, MCP-1, and TNF-α by activating AhR. CONCLUSION: BaP inhibit fat synthesis and oxidation while inducing inflammation by activating AhR, leading to WAT dysfunction and causing metabolic complications.
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Benzo(a)pireno/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Receptores de Hidrocarboneto Arílico/metabolismo , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Tecido Adiposo Branco/anatomia & histologia , Tecido Adiposo Branco/efeitos dos fármacos , Animais , Relação Dose-Resposta a Droga , Teste de Tolerância a Glucose , Resistência à Insulina , Lipídeos/sangue , Camundongos , Camundongos Endogâmicos C57BL , Receptores de Hidrocarboneto Arílico/efeitos dos fármacosRESUMO
The self-splicing of group II introns during RNA processing depends on their catalytic structure and is influenced by numerous factors that promote the formation of that structure through direct binding. Here we report that C-to-U editing at a specific position in two nad7 introns is essential to splicing, which also implies that the catalytic activity of non-functional group II introns could be restored by editing. We characterized a maize (Zea mays) mutant, dek46, with a defective kernel phenotype; Dek46 encodes a pentatricopeptide repeat DYW protein exclusively localized in mitochondria. Analyses of the coding regions of mitochondrial transcripts did not uncover differences in RNA editing between dek46 mutant and wild-type maize, but showed that splicing of nad7 introns 3 and 4 is severely reduced in the mutant. Furthermore, editing at nucleotide 22 of domain 5 (D5-C22) of both introns is abolished in dek46. We constructed chimeric introns by swapping D5 of P.li.LSUI2 with D5 of nad7 intron 3. In vitro splicing assays indicated that the chimeric intron containing D5-U22 can be self-spliced, but the one containing D5-C22 cannot. These results indicate that DEK46 functions in the C-to-U editing of D5-C22 of both introns, and the U base at this position is critical to intron splicing.
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Íntrons , Mitocôndrias/metabolismo , Sementes/crescimento & desenvolvimento , Zea mays/crescimento & desenvolvimento , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteínas de Plantas/fisiologia , Splicing de RNA , RNA de Plantas/genética , RNA de Plantas/metabolismo , Sementes/metabolismo , Zea mays/metabolismoRESUMO
Hydrogen sulfide (H2S), which is closely related to various cardiovascular disorders, lowers blood pressure (BP), but whether this action is mediated via the modification of baroreflex afferent function has not been elucidated. Therefore, the current study aimed to investigate the role of the baroreflex afferent pathway in H2S-mediated autonomic control of BP regulation. The results showed that baroreflex sensitivity (BRS) was increased by acute intravenous NaHS (a H2S donor) administration to renovascular hypertensive (RVH) and control rats. Molecular expression data also showed that the expression levels of critical enzymes related to H2S were aberrantly downregulated in the nodose ganglion (NG) and nucleus tractus solitarius (NTS) in RVH rats. A clear reduction in BP by the microinjection of NaHS or L-cysteine into the NG was confirmed in both RVH and control rats, and a less dramatic effect was observed in model rats. Furthermore, the beneficial effects of NaHS administered by chronic intraperitoneal infusion on dysregulated systolic blood pressure (SBP), cardiac parameters, and BRS were verified in RVH rats. Moreover, the increase in BRS was attributed to activation and upregulation of the ATP-sensitive potassium (KATP) channels Kir6.2 and SUR1, which are functionally expressed in the NG and NTS. In summary, H2S plays a crucial role in the autonomic control of BP regulation by improving baroreflex afferent function due at least in part to increased KATP channel expression in the baroreflex afferent pathway under physiological and hypertensive conditions.
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Vias Aferentes/metabolismo , Barorreflexo/fisiologia , Pressão Sanguínea/fisiologia , Sulfeto de Hidrogênio/metabolismo , Hipertensão/fisiopatologia , Animais , Anti-Hipertensivos/farmacologia , Barorreflexo/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Cardiotônicos/farmacologia , Cistationina beta-Sintase/metabolismo , Cistationina gama-Liase/metabolismo , Sulfeto de Hidrogênio/farmacologia , Hipertensão/tratamento farmacológico , Masculino , Gânglio Nodoso/efeitos dos fármacos , Gânglio Nodoso/enzimologia , Gânglio Nodoso/metabolismo , Canais de Potássio Corretores do Fluxo de Internalização/metabolismo , Ratos Sprague-Dawley , Núcleo Solitário/efeitos dos fármacos , Núcleo Solitário/enzimologia , Núcleo Solitário/metabolismo , Sulfetos/farmacologia , Receptores de Sulfonilureias/metabolismo , Sulfurtransferases/metabolismoRESUMO
Herein, an effective tandem catalysis strategy is developed to improve the selectivity of the CO2 RR towards C2 H4 by multiple distinct catalytic sites in local vicinity. An earth-abundant elements-based tandem electrocatalyst PTF(Ni)/Cu is constructed by uniformly dispersing Cu nanoparticles (NPs) on the porphyrinic triazine framework anchored with atomically isolated nickel-nitrogen sites (PTF(Ni)) for the enhanced CO2 RR to produce C2 H4 . The Faradaic efficiency of C2 H4 reaches 57.3 % at -1.1â V versus the reversible hydrogen electrode (RHE), which is about 6 times higher than the non-tandem catalyst PTF/Cu, which produces CH4 as the major carbon product. The operando infrared spectroscopy and theoretic density functional theory (DFT) calculations reveal that the local high concentration of CO generated by PTF(Ni) sites can facilitate the C-C coupling to form C2 H4 on the nearby Cu NP sites. The work offers an effective avenue to design electrocatalysts for the highly selective CO2 RR to produce multicarbon products via a tandem route.
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The electrocatalytic conversion of CO2 into value-added chemicals is a promising approach to realize a carbon-energy balance. However, low current density still limits the application of the CO2 electroreduction reaction (CO2 RR). Metal-organic frameworks (MOFs) are one class of promising alternatives for the CO2 RR due to their periodically arranged isolated metal active sites. However, the poor conductivity of traditional MOFs usually results in a low current density in CO2 RR. We have prepared conductive two-dimensional (2D) phthalocyanine-based MOF (NiPc-NiO4 ) nanosheets linked by nickel-catecholate, which can be employed as highly efficient electrocatalysts for the CO2 RR to CO. The obtained NiPc-NiO4 has a good conductivity and exhibited a very high selectivity of 98.4 % toward CO production and a large CO partial current density of 34.5â mA cm-2 , outperforming the reported MOF catalysts. This work highlights the potential of conductive crystalline frameworks in electrocatalysis.
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The electroreduction of CO2 to value-added chemicals such as CO is a promising approach to realize carbon-neutral energy cycle, but still remains big challenge including low current density. Covalent organic frameworks (COFs) with abundant accessible active single-sites can offer a bridge between homogeneous and heterogeneous electrocatalysis, but the low electrical conductivity limits their application for CO2 electroreduction reaction (CO2 RR). Here, a 2D conductive Ni-phthalocyanine-based COF, named NiPc-COF, is synthesized by condensation of 2,3,9,10,16,17,23,24-octa-aminophthalocyaninato Ni(II) and tert-butylpyrene-tetraone for highly efficient CO2 RR. Due to its highly intrinsic conductivity and accessible active sites, the robust conductive 2D NiPc-COF nanosheets exhibit very high CO selectivity (>93%) in a wide range of the applied potentials of -0.6 to -1.1 V versus the reversible hydrogen electrode (RHE) and large partial current density of 35 mA cm-2 at -1.1 V versus RHE in aqueous solution that surpasses all the conventional COF electrocatalysts. The robust NiPc-COF that is bridged by covalent pyrazine linkage can maintain its CO2 RR activity for 10 h. This work presents the implementation of the conductive COF nanosheets for CO2 RR and provides a strategy to enhance energy conversion efficiency in electrocatalysis.
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We report a detailed study of tunneling spectra measured on 2H-Ta_{x}Nb_{1-x}Se_{2} (x=0â¼0.1) single crystals using a low-temperature scanning tunneling microscope. The prominent gaplike feature, which has not been understood for a long time, was found to be accompanied by some "in-gap" fine structures. By investigating the second-derivative spectra and their temperature and magnetic field dependencies, we were able to prove that inelastic electron tunneling is the origin of these features and obtain the Eliashberg function of 2H-Ta_{x}Nb_{1-x}Se_{2} at an atomic scale, providing a potential way to study the local Eliashberg function and the phonon spectra of the related transition-metal dichalcogenides.
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The research progress of puerarin and its derivatives in anti-inflammatory and anti-gout activities was reviewed in this paper. Puerarin possesses anti-inflammatory activity by affecting immunocyte, inflammation cytokines and signaling pathway. Puerarin also has anti-gout activity through inhibition of xanthine oxidase, promoting the excretion of uric acid to reduce serum uric acid level. Although its ability in reducing uric acid level was lower than that of allopurinol in clinical application, puerarin can also enhance the total antioxidant and free radical scavenging with stronger anti-inflammatory effect, so it will be a promising research direction to find new drugs with better anti-gout activity and less side effects by modifying the chemical structure of puerarin.
Assuntos
Anti-Inflamatórios/farmacologia , Supressores da Gota/farmacologia , Gota/tratamento farmacológico , Isoflavonas/farmacologia , Humanos , Ácido Úrico/sangue , Xantina Oxidase/antagonistas & inibidoresRESUMO
It is important and challenging to utilise CO2 and NO3- as a feedstock for electrosynthesis of urea. Herein, we reported a stable 2D metal-organic framework (MOF) Cu-HATNA, possessing planar CuO4 active sites, as an efficient electrocatalyst for coupling CO2 and NO3- into urea, achieving a high yield rate of 1.46 g h-1 gcat-1 with a current density of 44.2 mA cm-1 at -0.6 V vs. RHE. This performance surpasses most of the previously reported catalysts, revealing the great prospects of MOFs in sustainable urea synthesis.