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1.
Chem Rev ; 124(7): 3648-3693, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38518224

RESUMO

CO2 electrolyzers have progressed rapidly in energy efficiency and catalyst selectivity toward valuable chemical feedstocks and fuels, such as syngas, ethylene, ethanol, and methane. However, each component within these complex systems influences the overall performance, and the further advances needed to realize commercialization will require an approach that considers the whole process, with the electrochemical cell at the center. Beyond the cell boundaries, the electrolyzer must integrate with upstream CO2 feeds and downstream separation processes in a way that minimizes overall product energy intensity and presents viable use cases. Here we begin by describing upstream CO2 sources, their energy intensities, and impurities. We then focus on the cell, the most common CO2 electrolyzer system architectures, and each component within these systems. We evaluate the energy savings and the feasibility of alternative approaches including integration with CO2 capture, direct conversion of flue gas and two-step conversion via carbon monoxide. We evaluate pathways that minimize downstream separations and produce concentrated streams compatible with existing sectors. Applying this comprehensive upstream-to-downstream approach, we highlight the most promising routes, and outlook, for electrochemical CO2 reduction.

2.
Proc Natl Acad Sci U S A ; 120(34): e2302603120, 2023 08 22.
Artigo em Inglês | MEDLINE | ID: mdl-37579161

RESUMO

Certain transmembrane and membrane-tethered signaling proteins export from cilia as BBSome cargoes via the outward BBSome transition zone (TZ) diffusion pathway, indispensable for maintaining their ciliary dynamics to enable cells to sense and transduce extracellular stimuli inside the cell. Murine Rab-like 2 (Rabl2) GTPase resembles Chlamydomonas Arf-like 3 (ARL3) GTPase in promoting outward TZ passage of the signaling protein cargo-laden BBSome. During this process, ARL3 binds to and recruits the retrograde IFT train-dissociated BBSome as its effector to diffuse through the TZ for ciliary retrieval, while how RABL2 and ARL3 cross talk in this event remains uncertain. Here, we report that Chlamydomonas RABL2 in a GTP-bound form (RABL2GTP) cycles through cilia via IFT as an IFT-B1 cargo, dissociates from retrograde IFT trains at a ciliary region right above the TZ, and converts to RABL2GDP for activating ARL3GDP as an ARL3 guanine nucleotide exchange factor. This confers ARL3GTP to detach from the ciliary membrane and become available for binding and recruiting the phospholipase D (PLD)-laden BBSome, autonomous of retrograde IFT association, to diffuse through the TZ for ciliary retrieval. Afterward, RABL2GDP exits cilia by being bound to the ARL3GTP/BBSome entity as a BBSome cargo. Our data identify ciliary signaling proteins exported from cilia via the RABL2-ARL3 cascade-mediated outward BBSome TZ diffusion pathway. According to this model, hedgehog signaling defect-induced Bardet-Biedl syndrome caused by RABL2 mutations in humans could be well explained in a mutation-specific manner, providing us with a mechanistic understanding behind the outward BBSome TZ passage required for proper ciliary signaling.


Assuntos
Cílios , Proteínas Hedgehog , Humanos , Fatores de Ribosilação do ADP/genética , Fatores de Ribosilação do ADP/metabolismo , Cílios/metabolismo , GTP Fosfo-Hidrolases/metabolismo , Guanosina Trifosfato/metabolismo , Proteínas Hedgehog/metabolismo , Proteínas de Membrana/metabolismo , Transporte Proteico/genética , Proteínas rab de Ligação ao GTP/metabolismo , Chlamydomonas
3.
Proc Natl Acad Sci U S A ; 120(13): e2218819120, 2023 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-36943875

RESUMO

Certain ciliary transmembrane and membrane-tethered signaling proteins migrate from the ciliary tip to base via retrograde intraflagellar transport (IFT), essential for maintaining their ciliary dynamics to enable cells to sense and transduce extracellular stimuli inside the cell. During this process, the BBSome functions as an adaptor between retrograde IFT trains and these signaling protein cargoes. The Arf-like 13 (ARL13) small GTPase resembles ARL6/BBS3 in facilitating these signaling cargoes to couple with the BBSome at the ciliary tip prior to loading onto retrograde IFT trains for transporting towards the ciliary base, while the molecular basis for how this intricate coupling event happens remains elusive. Here, we report that Chlamydomonas ARL13 only in a GTP-bound form (ARL13GTP) anchors to the membrane for diffusing into cilia. Upon entering cilia, ARL13 undergoes GTPase cycle for shuttling between the ciliary membrane (ARL13GTP) and matrix (ARL13GDP). To achieve this goal, the ciliary membrane-anchored BBS3GTP binds the ciliary matrix-residing ARL13GDP to activate the latter as an ARL13 guanine nucleotide exchange factor. At the ciliary tip, ARL13GTP recruits the ciliary matrix-residing and post-remodeled BBSome as an ARL13 effector to anchor to the ciliary membrane. This makes the BBSome spatiotemporally become available for the ciliary membrane-tethered phospholipase D (PLD) to couple with. Afterward, ARL13GTP hydrolyzes GTP for releasing the PLD-laden BBSome to load onto retrograde IFT trains. According to this model, hedgehog signaling defects associated with ARL13b and BBS3 mutations in humans could be satisfactorily explained, providing us a mechanistic understanding behind BBSome-cargo coupling required for proper ciliary signaling.


Assuntos
Síndrome de Bardet-Biedl , Cílios , Humanos , Cílios/metabolismo , Transporte Proteico/genética , Síndrome de Bardet-Biedl/genética , Proteínas Hedgehog/metabolismo , Proteínas de Membrana/metabolismo , Guanosina Trifosfato/metabolismo , Flagelos/metabolismo
4.
J Am Chem Soc ; 146(12): 8641-8649, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38470826

RESUMO

Renewable-energy-powered electrosynthesis has the potential to contribute to decarbonizing the production of propylene glycol, a chemical that is used currently in the manufacture of polyesters and antifreeze and has a high carbon intensity. Unfortunately, to date, the electrooxidation of propylene under ambient conditions has suffered from a wide product distribution, leading to a low faradic efficiency toward the desired propylene glycol. We undertook mechanistic investigations and found that the reconstruction of Pd to PdO occurs, followed by hydroxide formation under anodic bias. The formation of this metastable hydroxide layer arrests the progressive dissolution of Pd in a locally acidic environment, increases the activity, and steers the reaction pathway toward propylene glycol. Rh-doped Pd further improves propylene glycol selectivity. Density functional theory (DFT) suggests that the Rh dopant lowers the energy associated with the production of the final intermediate in propylene glycol formation and renders the desorption step spontaneous, a concept consistent with experimental studies. We report a 75% faradic efficiency toward propylene glycol maintained over 100 h of operation.

5.
Artigo em Inglês | MEDLINE | ID: mdl-38446716

RESUMO

OBJECTIVES: The present study aims to explore the application value of the air bronchogram (AB) sign and other computed tomography (CT) signs in the early diagnosis of lung adenocarcinoma (LUAD). METHOD: The pathological information and CT images of 130 patients diagnosed with N0 and M0 solitary pulmonary nodules (diameter ≤3 cm) and treated with surgical resection in our hospital between June 2021 and June 2022 were analyzed. RESULTS: The patients were divided into the benign pulmonary nodule (BPN) group (14 cases), the AIS group (30 cases), the MIA group (10 cases), and the IAC group (76 cases). Among the 116 patients with AIS and LUAD, 96 showed an AB sign. Among the 14 patients with BPN, only 4 patients showed an AB sign. The average CT value and maximum diameter were significantly higher in the IAC group than in the AIS and MIA groups. In the BPN group, 5 patients had an average CT value of >80 HU. Among all LUAD-based groups, there was only 1 patient with a CT value of >60 HU. CONCLUSIONS: The identification of the AB sign based on CT imaging facilitates the differentiation between benign and malignant nodules. The CT value and maximum diameter of pulmonary adenocarcinoma nodules increase with the increase of the malignancy degree. The nodule type, CT value, and maximum diameter are useful for predicting the pathological type and prognosis. If the average CT value of pulmonary nodules is >80 HU, LUAD may be excluded.

6.
Proc Natl Acad Sci U S A ; 118(35)2021 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-34446551

RESUMO

Many G protein-coupled receptors and other signaling proteins localize to the ciliary membrane for regulating diverse cellular processes. The BBSome composed of multiple Bardet-Biedl syndrome (BBS) proteins is an intraflagellar transport (IFT) cargo adaptor essential for sorting signaling proteins in and/or out of cilia via IFT. Leucine zipper transcription factor-like 1 (LZTFL1) protein mediates ciliary signaling by controlling BBSome ciliary content, reflecting how LZTFL1 mutations could cause BBS. However, the mechanistic mechanism underlying this process remains elusive thus far. Here, we show that LZTFL1 maintains BBSome ciliary dynamics by finely controlling BBSome recruitment to the basal body and its reassembly at the ciliary tip simultaneously in Chlamydomonas reinhardtii LZTFL1 directs BBSome recruitment to the basal body via promoting basal body targeting of Arf-like 6 GTPase BBS3, thus deciding the BBSome amount available for loading onto anterograde IFT trains for entering cilia. Meanwhile, LZTFL1 stabilizes the IFT25/27 component of the IFT-B1 subcomplex in the cell body so as to control its presence and amount at the basal body for entering cilia. Since IFT25/27 promotes BBSome reassembly at the ciliary tip for loading onto retrograde IFT trains, LZTFL1 thus also directs BBSome removal out of cilia. Therefore, LZTFL1 dysfunction deprives the BBSome of ciliary presence and generates Chlamydomonas cells defective in phototaxis. In summary, our data propose that LZTFL1 maintains BBSome dynamics in cilia by such a dual-mode system, providing insights into how LZTFL1 mediates ciliary signaling through maintaining BBSome ciliary dynamics and the pathogenetic mechanism of the BBS disorder as well.


Assuntos
Chlamydomonas reinhardtii/fisiologia , Cílios/fisiologia , Fototaxia , Fatores de Transcrição/fisiologia , Síndrome de Bardet-Biedl , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Ligação Proteica , Transdução de Sinais
7.
J Cell Physiol ; 238(3): 549-565, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36852649

RESUMO

Certain ciliary transmembrane and membrane-associated signaling proteins export from cilia as intraflagellar transport (IFT) cargoes in a BBSome-dependent manner. Upon reaching the ciliary tip via anterograde IFT, the BBSome disassembles before being reassembled to form an intact entity for cargo phospholipase D (PLD) coupling. During this BBSome remodeling process, Chlamydomonas Rab-like 4 GTPase IFT27, by binding its partner IFT25 to form the heterodimeric IFT25/27, is indispensable for BBSome reassembly. Here, we show that IFT27 binds IFT25 in an IFT27 nucleotide-independent manner. IFT25/27 and the IFT subcomplexes IFT-A and -B are irrelevant for maintaining the stability of one another. GTP-loading onto IFT27 enhances the IFT25/27 affinity for binding to the IFT-B subcomplex core IFT-B1 entity in cytoplasm, while GDP-bound IFT27 does not prevent IFT25/27 from entering and cycling through cilia by integrating into IFT-B1. Upon at the ciliary tip, IFT25/27 cycles on and off IFT-B1 and this process is irrelevant with the nucleotide state of IFT27. During BBSome remodeling at the ciliary tip, IFT25/27 promotes BBSome reassembly independent of IFT27 nucleotide state, making postremodeled BBSomes available for PLD to interact with. Thus, IFT25/27 facilitates BBSome-dependent PLD export from cilia via controlling availability of intact BBSomes at the ciliary tip, while IFT27 nucleotide state does not participate in this regulatory event.


Assuntos
Chlamydomonas , Cílios , Nucleotídeos , Fosfolipase D , Proteínas rab de Ligação ao GTP , Cílios/química , Cílios/metabolismo , Flagelos/química , Flagelos/metabolismo , Fosfolipase D/metabolismo , Transporte Proteico , Transdução de Sinais , Chlamydomonas/citologia , Chlamydomonas/enzimologia , Chlamydomonas/metabolismo , Proteínas rab de Ligação ao GTP/metabolismo , Guanosina Trifosfato/metabolismo , Guanosina Difosfato/metabolismo
8.
J Am Chem Soc ; 145(14): 7829-7836, 2023 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-37010254

RESUMO

Acidic water electrolysis enables the production of hydrogen for use as a chemical and as a fuel. The acidic environment hinders water electrolysis on non-noble catalysts, a result of the sluggish kinetics associated with the adsorbate evolution mechanism, reliant as it is on four concerted proton-electron transfer steps. Enabling a faster mechanism with non-noble catalysts will help to further advance acidic water electrolysis. Here, we report evidence that doping Ba cations into a Co3O4 framework to form Co3-xBaxO4 promotes the oxide path mechanism and simultaneously improves activity in acidic electrolytes. Co3-xBaxO4 catalysts reported herein exhibit an overpotential of 278 mV at 10 mA/cm2 in 0.5 M H2SO4 electrolyte and are stable over 110 h of continuous water oxidation operation. We find that the incorporation of Ba cations shortens the Co-Co distance and promotes OH adsorption, findings we link to improved water oxidation in acidic electrolyte.

9.
Zhongguo Zhong Yao Za Zhi ; 45(2): 451-456, 2020 Jan.
Artigo em Zh | MEDLINE | ID: mdl-32237331

RESUMO

To investigate the efficacy of Huangqin Qingre Chubi Capsules(HQC) in patients with ankylosing spondylitis(AS) and its effect on oxidative stress, and to explore its possible mechanism. Fifty-eight cases of AS patients were randomly divided into HQC group and salazosulfapyridine(SASP) group. Another 30 healthy people were employed as a control group. Superoxide dismutase(SOD), total antioxidant capacity(TAOC), malondialdehyde(MDA), lipid peroxidatio(LPO), interleukin-1ß(IL-1ß), IL-10, IL-4, and tumor necrosis factor-α(TNF-α) were detected by ELISA. The mRNA expression levels of AMP-activated protein kinase(AMPK-α), forkhead box O3a(FOXO3a), manganese superoxide dismutase(MnSOD), and peroxisome proliferator-activated receptor gamma(PPARγ) were detected by Real-time fluorescence quantitative polymerase chain reaction(RT-qPCR). The protein expression levels of AMPK-α, FOXO3a, p-FOXO3a, MnSOD, and PPARγ were detected by Western blot. A questionnaire was used to evaluate the disease activity score and observe the clinical efficacy of HQC in AS patients. The levels of MDA, LPO, TNF-α, and IL-1ß were significantly increased in the peripheral blood of AS patients, and SOD, TAOC, IL-4, IL-10 levels were significantly decreased. After HQC treatment, scores of disease active indexes were all decreased, and its clinical efficacy was significantly higher than that in SASP group. After HQC treatment, TAOC, SOD, IL-4, IL-10 were increased and MDA, LPO, TNF-α, IL-1ß were decreased; mRNA levels of AMPK-α, FOXO3a, MnSOD, PPARγ and protein levels of AMPK-α, FOXO3a, p-FOXO3a, MnSOD, PPARγ were increased(P<0.01 or P<0.05). HQC can effectively improve the clinical symptoms and oxidative stress of AS patients, and its mechanism may be related to activating PPARγ and up-regulating AMPK/FOXO3a signal pathway.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Medicamentos de Ervas Chinesas/uso terapêutico , Proteína Forkhead Box O3/metabolismo , Estresse Oxidativo , PPAR gama/metabolismo , Espondilite Anquilosante/tratamento farmacológico , Cápsulas , Humanos , Scutellaria baicalensis/química , Transdução de Sinais , Sulfassalazina/uso terapêutico
10.
Proteomics ; 19(7): e1800197, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30688006

RESUMO

It has been reported recently that type 2 diabetes promotes centrosome amplification via 14-3-3σ/ROCK1 complex. In the present study, 14-3-3σ interacting proteins are characterized and their roles in the centrosome amplification by high glucose, insulin, and palmitic acid are investigated. Co-immunoprecipitation in combination with MS analysis identified 134 proteins that interact with 14-3-3σ, which include heat shock 70 kDa protein 4 (Hsp74). Gene ontology analyses reveal that many of them are enriched in binding activity. Kyoto Encyclopedia of Genes and Genomes analysis shows that the top three enriched pathways are ribosome, carbon metabolism, and biosynthesis of amino acids. Molecular and functional investigations show that the high glucose, insulin, and palmitic acid increase the expression and binding of 14-3-3σ and Hsp74 as well as centrosome amplification, all of which are inhibited by knockdown of 14-3-3σ or Hsp74. Moreover, molecular docking analysis shows that the interaction between the 14-3-3σ and the Hsp74 is mainly through hydrophobic contacts and a lesser degree ionic interactions and hydrogen bond by different amino acids residues. In conclusion, the results suggest that the experimental treatment triggers centrosome amplification via upregulations of expression and binding of 14-3-3σ and Hsp74.


Assuntos
Proteínas 14-3-3/metabolismo , Proteínas de Transporte/metabolismo , Centrossomo/metabolismo , Glucose/farmacologia , Proteínas de Choque Térmico HSP70/metabolismo , Insulina/farmacologia , Ácido Palmítico/farmacologia , Western Blotting , Centrossomo/efeitos dos fármacos , Biologia Computacional/métodos , Células HCT116 , Humanos , Espectrometria de Massas , Microscopia Confocal , Proteínas Mitocondriais , Simulação de Acoplamento Molecular , Ligação Proteica/efeitos dos fármacos
11.
J Cell Physiol ; 234(10): 18230-18248, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30883760

RESUMO

There is evidence that cadmium can initiate carcinogenesis. However, the underlying mechanisms remain unknown. There is also evidence that moderate centrosome amplification can initiate tumorigenesis. The present study investigated whether cadmium could trigger cell centrosome amplification, and examined the underlying molecular mechanisms. We found that cadmium was able to cause cell centrosome amplification at the subtoxic concentrations, in a dose-dependent manner. It could cause centrosome amplification via the signaling of reactive oxygen species (ROS). Proteomic analysis revealed that cadmium caused differential expressions of three proteins, which included HSPA1A which is associated with endoplasmic reticulum (ER) stress. Western blot analysis confirmed that cadmium upregulated HSPA1A. Further analyses showed that cadmium upregulated Bip and decreased the phosphorylation of ASK1 as well as increased the phosphorylation of MKK7 and c-Jun N-terminal kinases (JNK). Knockdown of JNK2 using small interfering RNA inhibited the cadmium-induced centrosome amplification but not the level of ROS. N-acetylcysteine did not inhibit the cadmium-activated ER stress pathway. In conclusion, our results suggest that cadmium can induce cell centrosome amplification via ROS as well as ER stress through the Bip-TRAF2-ASK1-MKK7-JNK signaling route, in parallel. More studies are required to clarify whether centrosome amplification underlies cadmium-induced carcinogenesis.


Assuntos
Cádmio/farmacologia , Centrossomo/efeitos dos fármacos , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Linhagem Celular Tumoral , Células HCT116 , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , Proteômica/métodos , Regulação para Cima/efeitos dos fármacos
12.
Med Sci Monit ; 25: 6767-6774, 2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31495827

RESUMO

BACKGROUND Rheumatoid arthritis (RA) is a chronic autoimmune disease targeting joints. This research aimed to explore the effects of Xinfeng capsules (XFC) on cardiac injury in adjuvant arthritis (AA) model rats and assessed the associated mechanism. MATERIAL AND METHODS An adjuvant arthritis (AA) rat model was established by intracutaneously injection with Freund's complete adjuvant (FCA). Model rats were divided into 4 groups: an AA model group, an astragalus polysaccharides (APS) group, a methotrexate (MTX) group, and an XFC and triptolide (TPT) group. Hematoxylin-eosin (HE) staining was used to observe histopathologic changes. TUNEL assay was utilized to evaluate the apoptosis of cardiomyocytes. ELISA was utilized to evaluate levels of tumor necrosis factor alpha (TNF-alpha), interleukin 17 (IL-17), and interleukin 6 (IL-6) in myocardial tissues. Quantitative RT-PCR (qRT-PCR) was used to detect microRNA-21 (miRNA21) levels. Mitogen-activated protein kinase (MAPK)/p38, Toll-like receptor 4 (TLR4), and nuclear kappa B (NF-kappaB)/p65 levels were evaluated using Western blot. RESULTS XFC significantly improved proinflammatory response compared to the AA model group (p<0.05). XFC treatment significantly decreased the number of cells staining TUNEL-positive compared with the model group (p<0.05). XFC treatment significantly reduced TNF-alpha, IL-17, and IL-6 levels in myocardial tissues compared to the model group (p<0.05). Levels of miRNA21 were significantly lower in the XFC group compared to the AA model group (p<0.05). TLR4, MAPK/p38, and NF-kappaB/p65 expression levels were significantly lower in the XFC group than in the model group (p<0.05). CONCLUSIONS Xinfeng capsule, a traditional Chinese medicine preparation, protects against cardiac injury in AA rats by modulating proinflammatory cytokines expression via the TLR4/MAPK/NF-kappaB signaling pathway.


Assuntos
Artrite Experimental/tratamento farmacológico , Artrite Experimental/metabolismo , Citocinas/metabolismo , Medicamentos de Ervas Chinesas/uso terapêutico , Mediadores da Inflamação/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , NF-kappa B/metabolismo , Receptor 4 Toll-Like/metabolismo , Animais , Apoptose/efeitos dos fármacos , Artrite Experimental/genética , Artrite Experimental/patologia , Cápsulas , Citocinas/sangue , Modelos Animais de Doenças , Medicamentos de Ervas Chinesas/farmacologia , Regulação da Expressão Gênica , Inflamação/patologia , Mediadores da Inflamação/sangue , MicroRNAs/genética , MicroRNAs/metabolismo , Miocárdio/patologia , Fosforilação , Ratos Sprague-Dawley , Transdução de Sinais , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
13.
Anal Chem ; 87(5): 3019-26, 2015 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-25669135

RESUMO

We report an electrochemical sensor for telomerase activity detection based on spherical nucleic acids gold nanoparticles (SNAs AuNPs) triggered mimic-hybridization chain reaction (mimic-HCR) enzyme-free dual signal amplification. In the detection strategy, SNAs AuNPs and two hairpin probes were employed. SNAs AuNPs as the primary amplification element, not only hybridized with the telomeric repeats on the electrode to amplify signal but also initiated the subsequent secondary amplification, mimic-hybridization chain reaction of two hairpin probes. If the cells' extracts were positive for telomerase activity, SNAs AuNPs could be captured on the electrode. The carried initiators could trigger an alternative hybridization reaction of two hairpin probes that yielded nicked double helices. The signal was further amplified enzyme-free by numerous hexaammineruthenium(III) chloride ([Ru(NH3)6](3+), RuHex) inserting into double-helix DNA long chain by electrostatic interaction, each of which could generate an electrochemical signal at appropriate potential. With this method, a detection limit of down to 2 HeLa cells and a dynamic range of 10-10,000 cells were achieved. Telomerase activities of different cell lines were also successfully evaluated.


Assuntos
Técnicas Eletroquímicas/métodos , Eletrodos , Ouro/química , Nanopartículas Metálicas/química , Hibridização de Ácido Nucleico/métodos , Ácidos Nucleicos/química , Telomerase/metabolismo , Técnicas Biossensoriais/métodos , Células HeLa , Humanos , Limite de Detecção , Compostos de Rutênio/química
14.
Nat Commun ; 15(1): 616, 2024 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-38242870

RESUMO

Electrosynthesis of acetate from CO offers the prospect of a low-carbon-intensity route to this valuable chemical--but only once sufficient selectivity, reaction rate and stability are realized. It is a high priority to achieve the protonation of the relevant intermediates in a controlled fashion, and to achieve this while suppressing the competing hydrogen evolution reaction (HER) and while steering multicarbon (C2+) products to a single valuable product--an example of which is acetate. Here we report interface engineering to achieve solid/liquid/gas triple-phase interface regulation, and we find that it leads to site-selective protonation of intermediates and the preferential stabilization of the ketene intermediates: this, we find, leads to improved selectivity and energy efficiency toward acetate. Once we further tune the catalyst composition and also optimize for interfacial water management, we achieve a cadmium-copper catalyst that shows an acetate Faradaic efficiency (FE) of 75% with ultralow HER (<0.2% H2 FE) at 150 mA cm-2. We develop a high-pressure membrane electrode assembly system to increase CO coverage by controlling gas reactant distribution and achieve 86% acetate FE simultaneous with an acetate full-cell energy efficiency (EE) of 32%, the highest energy efficiency reported in direct acetate electrosynthesis.

15.
Nat Nanotechnol ; 19(3): 311-318, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37996517

RESUMO

The electrochemical reduction of CO2 in acidic conditions enables high single-pass carbon efficiency. However, the competing hydrogen evolution reaction reduces selectivity in the electrochemical reduction of CO2, a reaction in which the formation of CO, and its ensuing coupling, are each essential to achieving multicarbon (C2+) product formation. These two reactions rely on distinct catalyst properties that are difficult to achieve in a single catalyst. Here we report decoupling the CO2-to-C2+ reaction into two steps, CO2-to-CO and CO-to-C2+, by deploying two distinct catalyst layers operating in tandem to achieve the desired transformation. The first catalyst, atomically dispersed cobalt phthalocyanine, reduces CO2 to CO with high selectivity. This process increases local CO availability to enhance the C-C coupling step implemented on the second catalyst layer, which is a Cu nanocatalyst with a Cu-ionomer interface. The optimized tandem electrodes achieve 61% C2H4 Faradaic efficiency and 82% C2+ Faradaic efficiency at 800 mA cm-2 at 25 °C. When optimized for single-pass utilization, the system reaches a single-pass carbon efficiency of 90 ± 3%, simultaneous with 55 ± 3% C2H4 Faradaic efficiency and a total C2+ Faradaic efficiency of 76 ± 2%, at 800 mA cm-2 with a CO2 flow rate of 2 ml min-1.

16.
Mol Biol Rep ; 40(8): 4737-45, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23666055

RESUMO

Carotenoid oxygenase is a key enzyme in carotenoid metabolism leading to the synthesis of two phytohormones, abscisic acid (ABA) and strigolactone, as well as norisoprenoids. Few studies have analyzed inter-relationship of the metabolic networks of these three substances. In this present paper, soybean carotenoid oxygenase genes were identified to reveal their phylogenetic relationships, and the transcriptional response of these genes to four abiotic stresses (NaCl, PEG, high and low temperature) and ABA treatment were investigated to characterize their potential roles in plant resistance. Positive selection was found in the branches of carotenoid cleavage dioxygenase (CCD1), CCD8 and NCED (9-cis-epoxycarotenoid oxygenase), indicating an adaptive evolution in these clades. In soybean eight carotenoid oxygenase genes were identified. The transcriptional responses of almost all of them under stress and ABA conditions were significantly altered when assessed by quantitative polymerase chain reaction. Notably, CCD1 and CCD4, previously known as the key genes in norisoprenoids metabolism, showed especially strong responses to the abiotic stresses and ABA treatment. Furthermore, transcription levels of CCD7 and CCD8, key genes for the strigolactone pathway, highly increased during ABA treatment providing further evidence that ABA is involved in regulating strigolactone metabolism. All of the carotenoid oxygenase genes in soybean are involved in plant abiotic stress physiology, and ABA is presumed to be a core regulatory substance. These findings provide some insights into the mechanisms that underlie the regulation of tolerance response to abiotic stresses in soybean.


Assuntos
Adaptação Biológica/genética , Regulação da Expressão Gênica de Plantas/genética , Glycine max/enzimologia , Oxigenases/genética , Filogenia , Estresse Fisiológico/genética , Ácido Abscísico/toxicidade , Teorema de Bayes , Biologia Computacional , Primers do DNA/genética , Dioxigenases/genética , Dioxigenases/metabolismo , Genoma de Planta/genética , Modelos Genéticos , Polietilenoglicóis/toxicidade , Seleção Genética , Cloreto de Sódio/toxicidade , Temperatura
17.
Nat Commun ; 14(1): 2958, 2023 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-37221228

RESUMO

Electrochemical CO2 reduction (CO2R) is an approach to closing the carbon cycle for chemical synthesis. To date, the field has focused on the electrolysis of ambient pressure CO2. However, industrial CO2 is pressurized-in capture, transport and storage-and is often in dissolved form. Here, we find that pressurization to 50 bar steers CO2R pathways toward formate, something seen across widely-employed CO2R catalysts. By developing operando methods compatible with high pressures, including quantitative operando Raman spectroscopy, we link the high formate selectivity to increased CO2 coverage on the cathode surface. The interplay of theory and experiments validates the mechanism, and guides us to functionalize the surface of a Cu cathode with a proton-resistant layer to further the pressure-mediated selectivity effect. This work illustrates the value of industrial CO2 sources as the starting feedstock for sustainable chemical synthesis.

18.
Adv Mater ; 35(16): e2210057, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36719140

RESUMO

Direct electrolysis of pH-neutral seawater to generate hydrogen is an attractive approach for storing renewable energy. However, due to the anodic competition between the chlorine evolution and the oxygen evolution reaction (OER), direct seawater splitting suffers from a low current density and limited operating stability. Exploration of catalysts enabling an OER overpotential below the hypochlorite formation overpotential (≈490 mV) is critical to suppress the chloride evolution and facilitate seawater splitting. Here, a proton-adsorption-promoting strategy to increase the OER rate is reported, resulting in a promoted and more stable neutral seawater splitting. The best catalysts herein are strong-proton-adsorption (SPA) materials such as palladium-doped cobalt oxide (Co3- x Pdx O4 ) catalysts. These achieve an OER overpotential of 370 mV at 10 mA cm-2 in pH-neutral simulated seawater, outperforming Co3 O4 by a margin of 70 mV. Co3- x Pdx O4 catalysts provide stable catalytic performance for 450 h at 200 mA cm-2 and 20 h at 1 A cm-2 in neutral seawater. Experimental studies and theoretical calculations suggest that the incorporation of SPA cations accelerates the rate-determining water dissociation step in neutral OER pathway, and control studies rule out the provision of additional OER sites as a main factor herein.

19.
Nat Commun ; 14(1): 3314, 2023 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-37286531

RESUMO

Renewable CH4 produced from electrocatalytic CO2 reduction is viewed as a sustainable and versatile energy carrier, compatible with existing infrastructure. However, conventional alkaline and neutral CO2-to-CH4 systems suffer CO2 loss to carbonates, and recovering the lost CO2 requires input energy exceeding the heating value of the produced CH4. Here we pursue CH4-selective electrocatalysis in acidic conditions via a coordination method, stabilizing free Cu ions by bonding Cu with multidentate donor sites. We find that hexadentate donor sites in ethylenediaminetetraacetic acid enable the chelation of Cu ions, regulating Cu cluster size and forming Cu-N/O single sites that achieve high CH4 selectivity in acidic conditions. We report a CH4 Faradaic efficiency of 71% (at 100 mA cm-2) with <3% loss in total input CO2 that results in an overall energy intensity (254 GJ/tonne CH4), half that of existing electroproduction routes.

20.
Am J Transl Res ; 14(8): 5295-5307, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36105044

RESUMO

BACKGROUND: Rheumatoid arthritis (RA) is a common autoimmune disease. Paederia scandens (Lour.) Merr is a common folk remedy used in Hainan, China, to dispel the wind and dampness associated with RA. METHODS: The active components of Paederia scandens were extracted using network pharmacology. The potential targets of active components were used to determine activated pathways, and the in vitro effects of Paederia scandens extracts were verified in RA fibroblast-like synoviocytes (HFLS-RA). RESULTS: We identified 27 active components using ultra-high-performance liquid chromatography (UHPLC)-quadrupole time-of-flight (QTOF)-mass spectrometry (MS). Among the major target genes with high connectivity, IL-1ß, PI3K, TNF, and JAK2 are known to play key roles in RA development. High-affinity interactions were identified between active compounds in Paederia scandens extract and Janus kinase JAK 2, which are key components of the JAK-signal transducer and activator of transcription (STAT) signaling pathway. In HFLS-RA cells, Paederia scandens extract treatment reduced the mRNA levels of IL-6, IL-1ß, and IL-17. Paederia scandens extract treatment also significantly inhibited the phosphorylation of JAK 2 and STAT3, regulating cell proliferation. CONCLUSIONS: Based on these results, we confirmed that Paederia scandens has potential for application as a therapeutic and preventive food and acts through the modulation and suppression of JAK-STAT pathway activation to control the inflammatory response in RA.

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