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1.
J Am Chem Soc ; 146(6): 3854-3860, 2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38305733

RESUMO

The low ionic conductivity and high desolvation barrier are the main challenges for organic electrolytes in rechargeable metal batteries, especially at low temperatures. The general strategy is to couple strong-solvation and weak-solvation solvents to give balanced physicochemical properties. However, the two challenges described above cannot be overcome at the same time. Herein, we combine two different kinds of weakly solvating solvents with a very low desolvation energy. Interestingly, the synergy between the weak-solvation solvents can break the locally ordered structure at a low temperature to enable higher ionic conductivity compared to those with individual solvents. Thus, facile desolvation and high ionic conductivity are achieved simultaneously, significantly improving the reversibility of electrode reactions at low temperatures. The Na metal anode can be stably cycled at 2 mA cm-2 at -40 °C for 1000 h. The Na||Na3V2(PO4)3 cell shows the reversible capacity of 64 mAh g-1 at 0.3 C after 300 cycles at -40 °C, and the capacity retention is 86%. This strategy is applicable to other sets of weak-solvation solvents, providing guidance for the development of electrolytes for low-temperature rechargeable metal batteries.

2.
J Am Chem Soc ; 146(18): 12538-12546, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38656110

RESUMO

There is growing acknowledgment that the properties of the electrochemical interfaces play an increasingly pivotal role in improving the performance of the hydrogen evolution reaction (HER). Here, we present, for the first time, direct dynamic spectral evidence illustrating the impact of the interaction between interfacial water molecules and adsorbed hydroxyl species (OHad) on the HER properties of Ni(OH)2 using Au/core-Ni(OH)2/shell nanoparticle-enhanced Raman spectroscopy. Notably, our findings highlight that the interaction between OHad and interfacial water molecules promotes the formation of weakly hydrogen-bonded water, fostering an environment conducive to improving the HER performance. Furthermore, the participation of OHad in the reaction is substantiated by the observed deprotonation step of Au@2 nm Ni(OH)2 during the HER process. This phenomenon is corroborated by the phase transition of Ni(OH)2 to NiO, as verified through Raman and X-ray photoelectron spectroscopy. The significant redshift in the OH-stretching frequency of water molecules during the phase transition confirms that surface OHad disrupts the hydrogen-bond network of interfacial water molecules. Through manipulation of the shell thickness of Au@Ni(OH)2, we additionally validate the interaction between OHad and interfacial water molecules. In summary, our insights emphasize the potential of electrochemical interfacial engineering as a potent approach to enhance electrocatalytic performance.

3.
Anal Chem ; 96(10): 4275-4281, 2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38409670

RESUMO

Surface-enhanced Raman scattering (SERS) can overcome the existing technological limitations, such as complex processes and harsh conditions in gaseous small-molecule detection, and advance the development of real-time gas sensing at room temperature. In this study, a SERS-based hydrogen bonding induction strategy for capturing and sensing gaseous acetic acid is proposed for the detection demands of gaseous acetic acid. This addresses the challenges of low adsorption of gaseous small molecules on SERS substrates and small Raman scattering cross sections and enables the first SERS-based detection of gaseous acetic acid by a portable Raman spectrometer. To provide abundant hydrogen bond donors and acceptors, 4-mercaptobenzoic acid (4-MBA) was used as a ligand molecule modified on the SERS substrate. Furthermore, a sensing chip with a low relative standard deviation (RSD) of 4.15% was constructed, ensuring highly sensitive and reliable detection. The hydrogen bond-induced acetic acid trapping was confirmed by experimental spectroscopy and density functional theory (DFT). In addition, to achieve superior accuracy compared to conventional methods, an innovative analytical method based on direct response hydrogen bond formation (IO-H/Iref) was proposed, enabling the detection of gaseous acetic acid at concentrations as low as 60 ppb. The strategy demonstrated a superior anti-interference capability in simulated breath and wine detection systems. Moreover, the high reusability of the chip highlights the significant potential for real-time sensing of gaseous acetic acid.

4.
Plant Biotechnol J ; 22(7): 1989-2006, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38412139

RESUMO

Regulation of grain size is a crucial strategy for improving the crop yield and is also a fundamental aspect of developmental biology. However, the underlying molecular mechanisms governing grain development in wheat remain largely unknown. In this study, we identified a wheat atypical basic helix-loop-helix (bHLH) transcription factor, TabHLH489, which is tightly associated with grain length through genome-wide association study and map-based cloning. Knockout of TabHLH489 and its homologous genes resulted in increased grain length and weight, whereas the overexpression led to decreased grain length and weight. TaSnRK1α1, the α-catalytic subunit of plant energy sensor SnRK1, interacted with and phosphorylated TabHLH489 to induce its degradation, thereby promoting wheat grain development. Sugar treatment induced TaSnRK1α1 protein accumulation while reducing TabHLH489 protein levels. Moreover, brassinosteroid (BR) promotes grain development by decreasing TabHLH489 expression through the transcription factor BRASSINAZOLE RESISTANT1 (BZR1). Importantly, natural variations in the promoter region of TabHLH489 affect the TaBZR1 binding ability, thereby influencing TabHLH489 expression. Taken together, our findings reveal that the TaSnRK1α1-TabHLH489 regulatory module integrates BR and sugar signalling to regulate grain length, presenting potential targets for enhancing grain size in wheat.


Assuntos
Brassinosteroides , Grão Comestível , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas , Triticum , Triticum/genética , Triticum/metabolismo , Triticum/crescimento & desenvolvimento , Brassinosteroides/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Grão Comestível/genética , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/metabolismo , Açúcares/metabolismo , Transdução de Sinais/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Estudo de Associação Genômica Ampla
5.
Sleep Breath ; 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38772968

RESUMO

PURPOSE: Major Depressive Disorder (MDD) and Insomnia Disorder (ID) are prevalent psychiatric conditions often occurring concurrently, leading to substantial impairment in daily functioning. Understanding the neurobiological underpinnings of these disorders and their comorbidity is crucial for developing effective interventions. This study aims to analyze changes in functional connectivity within attention networks and default mode networks in patients with depression and insomnia. METHODS: The functional connectivity alterations in individuals with MDD, ID, comorbid MDD and insomnia (iMDD), and healthy controls (HC) were assessed from a cohort of 174 participants. They underwent rs-fMRI scans, demographic assessments, and scale evaluations for depression and sleep quality. Functional connectivity analysis was conducted using region-of-interest (ROI) and whole-brain methods. RESULTS: The MDD and iMDD groups exhibited higher Hamilton Depression Scale (HAMD) scores compared to HC and ID groups (P < 0.001). Both ID and MDD groups displayed enhanced connectivity between the left and right orbital frontal cortex compared to HC (P < 0.05), while the iMDD group showed reduced connectivity compared to HC and ID groups (P < 0.05). In the left insula, reduced connectivity with the right medial superior frontal gyrus was observed across patient groups compared to HC (P < 0.05), with the iMDD group showing increased connectivity compared to MDD (P < 0.05). Moreover, alterations in functional connectivity between the left thalamus and left temporal pole were found in iMDD compared to HC and MDD (P < 0.05). Correlation analyses revealed associations between abnormal connectivity and symptom severity in MDD and ID groups. CONCLUSIONS: Our findings demonstrate distinct patterns of altered functional connectivity in individuals with MDD, ID, and iMDD compared to healthy controls. These findings contribute to a better understanding of the pathophysiology of depression and insomnia, which could be used as a reference for the diagnosis and treatments of these patients.

6.
Mar Drugs ; 22(6)2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38921598

RESUMO

To promote the bioconversion of marine chitin waste into value-added products, we expressed a novel pH-stable Micromonospora aurantiaca-derived chitinase, MaChi1, in Escherichia coli and subsequently purified, characterized, and evaluated it for its chitin-converting capacity. Our results indicated that MaChi1 is of the glycoside hydrolase (GH) family 18 with a molecular weight of approximately 57 kDa, consisting of a GH18 catalytic domain and a cellulose-binding domain. We recorded its optimal activity at pH 5.0 and 55 °C. It exhibited excellent stability in a wide pH range of 3.0-10.0. Mg2+ (5 mM), and dithiothreitol (10 mM) significantly promoted MaChi1 activity. MaChi1 exhibited broad substrate specificity and hydrolyzed chitin, chitosan, cellulose, soluble starch, and N-acetyl chitooligosaccharides with polymerization degrees ranging from three to six. Moreover, MaChi1 exhibited an endo-type cleavage pattern, and it could efficiently convert colloidal chitin into N-acetyl-D-glucosamine (GlcNAc) and (GlcNAc)2 with yields of 227.2 and 505.9 mg/g chitin, respectively. Its high chitin-degrading capacity and exceptional pH tolerance makes it a promising tool with potential applications in chitin waste treatment and bioactive oligosaccharide production.


Assuntos
Quitina , Quitinases , Micromonospora , Quitinases/metabolismo , Quitinases/química , Quitinases/isolamento & purificação , Quitinases/genética , Quitina/análogos & derivados , Quitina/metabolismo , Quitina/química , Concentração de Íons de Hidrogênio , Especificidade por Substrato , Micromonospora/enzimologia , Micromonospora/genética , Hidrólise , Escherichia coli/genética , Quitosana/química , Estabilidade Enzimática
7.
Nano Lett ; 23(21): 9872-9879, 2023 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-37856869

RESUMO

Lithium metal deposition is strongly affected by the intrinsic properties of the solid-electrolyte interphase (SEI) and working electrolyte, but a relevant understanding is far from complete. Here, by employing multiple electrochemical techniques and the design of SEI and electrolyte, we elucidate the electrochemistry of Li deposition under mass transport control. It is discovered that SEIs with a lower Li ion transference number and/or conductivity induce a distinctive current transition even under moderate potentiostatic polarization, which is associated with the control regime transition of Li ion transport from the SEI to the electrolyte. Furthermore, our findings help reveal the creation of a space-charge layer at the electrode/SEI interface due to the involvement of the diffusion process of Li ions through the SEI, which promotes the formation of dendrite embryos that develop and eventually trigger SEI breakage and the control regime transition of Li ion transport. Our insight into the very initial dendritic growth mechanism offers a bridge toward design and control for superior SEIs.

8.
Angew Chem Int Ed Engl ; 63(28): e202406535, 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38652809

RESUMO

Borophenes have sparked considerable interest owing to their fascinating physical characteristics and diverse polymorphism. However, borophene nanoribbons (BNRs) with widths less than 2 nm have not been achieved. Herein, we report the experimental realization of supernarrow BNRs. Combining scanning tunneling microscopy imaging with density functional theory modeling and ab initio molecular dynamics simulations, we demonstrate that, under the applied growth conditions, boron atoms can penetrate the outermost layer of Au(111) and form BNRs composed of a pair of zigzag (2,2) boron rows. The BNRs have a width self-contained to ∼1 nm and dipoles at the edges to keep them separated. They are embedded in the outermost Au layer and shielded on top by the evacuated Au atoms, free of the need for post-passivation. Scanning tunneling spectroscopy reveals distinct edge states, primarily attributed to the localized spin at the BNRs' zigzag edges. This work adds a new member to the boron material family and introduces a new physical feature to borophenes.

9.
J Am Chem Soc ; 145(23): 12760-12770, 2023 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-37154477

RESUMO

Tungsten and molybdenum carbides have shown great potential in catalysis and superconductivity. However, the synthesis of ultrathin W/Mo carbides with a controlled dimension and unique structure is still difficult. Here, inspired by the host-guest assembly strategy with single-walled carbon nanotubes (SWCNTs) as a transparent template, we reported the synthesis of ultrathin (0.8-2.0 nm) W2C and Mo2C nanowires confined in SWCNTs deriving from the encapsulated W/Mo polyoxometalate clusters. The atom-resolved electron microscope combined with spectroscopy and theoretical calculations revealed that the strong interaction between the highly carbophilic W/Mo and SWCNT resulted in the anisotropic growth of carbide nanowires along a specific crystal direction, accompanied by lattice strain and electron donation to the SWCNTs. The SWCNT template endowed carbides with resistance to H2O corrosion. Different from normal modification on the outer surface of SWCNTs, such M2C@SWCNTs (M = W, Mo) provided a delocalized and electron-enriched SWCNT surface to uniformly construct the negatively charged Pd catalyst, which was demonstrated to inhibit the formation of active PdHx hydride and thus achieve highly selective semihydrogenation of a series of alkynes. This work could provide a nondestructive way to design the electron-delocalized SWCNT surface and expand the methodology in synthesizing unusual 1D ultrathin carbophilic-metal nanowires (e.g., TaC, NbC, ß-W) with precise control of the anisotropy in SWCNT arrays.

10.
J Am Chem Soc ; 145(17): 9520-9529, 2023 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-37076447

RESUMO

Covalent organic frameworks (COFs) hold the potential in converting CO2 with water into value-added fuels and O2 to save the deteriorating ecological environment. However, reaching high yield and selectivity is a grand challenge under metal-, photosensitizer-, or sacrificial reagent-free conditions. Here, inspired by microstructures of natural leaves, we designed triazine-based COF membranes with the integration of steady light-harvesting sites, efficient catalytic center, and fast charge/mass transfer configuration to fabricate a novel artificial leaf for the first time. Significantly, a record high CO yield of 1240 µmol g-1 in a 4 h reaction, approximately 100% selectivity, and a long lifespan (at least 16 cycles) were achieved under gas-solid conditions without using any metal, photosensitizer, or sacrificial reagent. Unlike the existing knowledge, the chemical structural unit of triazine-imide-triazine and the unique physical form of the COF membrane are predominant for such a remarkable photocatalysis. This work opens a new pathway to simulating photosynthesis in leaves and may motivate relevant research in the future.

11.
J Am Chem Soc ; 145(23): 12717-12725, 2023 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-37268602

RESUMO

Enhancing the catalytic activity of Ru metal in the hydrogen oxidation reaction (HOR) potential range, improving the insufficient activity of Ru caused by its oxophilicity, is of great significance for reducing the cost of anion exchange membrane fuel cells (AEMFCs). Here, we use Ru grown on Au@Pd as a model system to understand the underlying mechanism for activity improvement by combining direct in situ surface-enhanced Raman spectroscopy (SERS) evidence of the catalytic reaction intermediate (OHad) with in situ X-ray diffraction (XRD), electrochemical characterization, as well as DFT calculations. The results showed that the Au@Pd@Ru nanocatalyst utilizes the hydrogen storage capacity of the Pd interlayer to "temporarily" store the activated hydrogen enriched at the interface, which spontaneously overflows at the "hydrogen-deficient interface" to react with OHad adsorbed on Ru. It is the essential reason for the enhanced catalytic activity of Ru at anodic potential. This work deepens our understanding of the HOR mechanism and provides new ideas for the rational design of advanced electrocatalysts.

12.
Biochem Biophys Res Commun ; 639: 189-196, 2023 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-36535138

RESUMO

Heart failure is one of the major fatal diseases and mitochondrial biogenesis is an important compensatory mechanism in the process of heart failure. Aldehyde dehydrogenase 2(ALDH2) is an important endogenous cardiac protective factor in mitochondria, but its role in mitochondrial biogenesis of cardiomyocytes remains unknown. In our study, transverse aorta constriction(TAC)-induced heart failure model was established in ALDH2-/- mice and wild-type mice. The cardiac function was examined by echocardiography at 4 weeks after operation. The myocardial tissue was stained by HE. The mitochondria morphology was observed using electron microscope, and the ATP content, Sirt1,PGC-1α and NRF1 expression were measured. Compared with wild-type mice, the cardiac function of ALDH2 -/- mice decreased significantly at 4 weeks after TAC. The proportion of mitochondrial area and mitochondrial crest/mitochondrial ratio decreased in the ALDH2-/- group after TAC. The ATP content decreased in ALDH2 -/- mice at 4 weeks after TAC. In the meantime, the expression of PGC-1α,Sirt 1 and NRF1 decreased in the ALDH2-/- TAC group compared with wild type TAC group.Neonatal rat cardiomyocytes were cultured and stretched. Cardiomyocytes were treated with the activator of ALDH2(Alda-1), Sirt1-SiRNA and PGC-1α-siRNA, respectively. The mitochondrial structure of cardiomyocytes was observed by transmission electron microscopy. The levels of PGC-1α,NRF-1 and Tfam were measured by Western blot.Mitochondrial biogenesis was enhanced in stretch cardiomyocytes treated with Alda-1.When cardiomyocytes were treated with Sirt1-SiRNA or PGC1α-SiRNA, the effect of Alda-1 in promoting mitochondrial biogenesis was attenuated.Therefore, these results suggested that the loss of ALDH2 aggravates mitochondrial biogenesis disorder in cardiac myocytes induced by TAC. Alda-1 could promote mitochondrial biogenesis in stretched cardiomyocytes, and this effect depends on Sirt1/PGC-1α pathway.


Assuntos
Aldeído-Desidrogenase Mitocondrial , Insuficiência Cardíaca , Doenças Mitocondriais , Miócitos Cardíacos , Animais , Camundongos , Ratos , Trifosfato de Adenosina/metabolismo , Aldeído-Desidrogenase Mitocondrial/genética , Aldeído-Desidrogenase Mitocondrial/metabolismo , Insuficiência Cardíaca/metabolismo , Doenças Mitocondriais/metabolismo , Miócitos Cardíacos/metabolismo , Biogênese de Organelas , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , RNA Interferente Pequeno/metabolismo , Sirtuína 1/metabolismo
13.
Analyst ; 148(17): 4044-4052, 2023 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-37522852

RESUMO

Heavy metal ions, which are over-emitted from industrial production, pose a major threat to the ecological environment and human beings. Among the present detection technologies, achieving rapid and on-site detection of contaminants remains a challenge. Herein, capillaries with three-dimensional (3D) hot spot constructures are fabricated to achieve repaid and ultrasensitive mercury ion (Hg2+) detection in water based on surface-enhanced Raman scattering (SERS). The 4-mercapto pyridine (4-Mpy) serves as the Raman reporter with high selectivity, enabling the detection of Hg2+ by changes in adsorption configuration at the trace level. Under optimized conditions, the SERS response of 4-Mpy for Hg2+ exhibits good linearity, ranging from 1 pM to 0.1 µM in a few minutes, and the detection limit of 0.2 pM is much lower than the maximum Hg2+ concentration of 10 nM allowed in drinking water, as defined by the US Environmental Protection Agency (EPA). Simultaneously, combined with the theoretical simulation and experimental results, the above results indicate that the SERS substrates possess outstanding performances in specificity, recovery rate and stability, which may hold great potential for achieving rapid and on-site environmental pollutant detection using a portable Raman spectrometer.

14.
Artigo em Inglês | MEDLINE | ID: mdl-37155004

RESUMO

BACKGROUND: Prolonged use of anti-arrhythmic drugs (AAD) beyond the post-ablation blanking period to maintain sinus rhythm has been adopted in clinical practice but without sufficient evidence. Dronedarone is an AAD valid for maintaining sinus rhythm with fewer side effects than other AAD for long-term use. OBJECTIVE: We sought to investigate the effect of prolonged use of dronedarone on the recurrence of non-paroxysmal AF patients beyond 3 months within the first year after ablation. METHODS: Non-paroxysmal AF patients will receive dronedarone for 3 months after radiofrequency ablation. Patients without drug side effects and atrial tachyarrhythmia (AT) recurrence will then be randomly divided into dronedarone and placebo groups and followed up until 1 year after ablation. The primary endpoint is the cumulative nonrecurrence rate post 3 months to 1 year after ablation. Patients will receive 7-day Holter monitoring (ECG patch) at 6, 9, and 12 months after ablation to evaluate AT recurrence. Secondary endpoints include dronedarone withdrawal due to side effects or intolerance of AT recurrence, time to the first recurrence, repeat ablation, electrical cardioversion, unscheduled emergency room visit, or re-hospitalization. CONCLUSION: This trial will evaluate whether prolonged use of dronedarone effectively reduces the recurrence rate after ablation in non-paroxysmal AF patients. The result of this trial will provide evidence for optimizing post-ablation anti-arrhythmic therapy. TRIAL REGISTRATION: ClinicalTrials.gov ; NCT05655468, 19-December-2022.

15.
J Chem Phys ; 158(9): 094704, 2023 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-36889978

RESUMO

An insightful understanding of the interaction between the electrolyte and reaction intermediate and how promotion reaction occurs of electrolyte is challenging in the electrocatalysis reaction. Herein, theoretical calculations are used to investigate the reaction mechanism of CO2 reduction reaction to CO with different electrolytes at the Cu(111) surface. By analyzing the charge distribution of the chemisorbed CO2 (CO2 δ-) formation process, we find that the charge transfer is from metal electrode transfer to CO2 and the hydrogen bond interaction between electrolytes and CO2 δ- not only plays a key role in the stabilization of CO2 δ- structure but also reduces the formation energy of *COOH. In addition, the characteristic vibration frequency of intermediates in different electrolyte solutions shows that H2O is a component of HCO3 -, promoting CO2 adsorption and reduction. Our results provide essential insights into the role of electrolyte solutions in interface electrochemistry reactions and help understand the catalysis process at the molecular level.

16.
Nano Lett ; 22(13): 5544-5552, 2022 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-35699945

RESUMO

In situ monitoring of the evolution of intermediates and catalysts during hydrogen oxidation reaction (HOR) processes and elucidating the reaction mechanism are crucial in catalysis and energy science. However, spectroscopic information on trace intermediates on catalyst surfaces is challenging to obtain due to the complexity of interfacial environments and lack of in situ techniques. Herein, core-shell nanoparticle-enhanced Raman spectroscopy was employed to probe alkaline HOR processes on representative PtRu surfaces. Direct spectroscopic evidence of an OHad intermediate and RuOx (Ru(+3)/Ru(+4)) surface oxides is simultaneously obtained, verifying that Ru doping onto Pt promotes OHad adsorption on the RuOx surface to react with Had adsorption on the Pt surface to form H2O. In situ Raman, XPS, and DFT results reveal that RuOx coverage tunes the electronic structure of PtRuOx to optimize the adsorption energy of OHad on catalyst surfaces, leading to an improvement in HOR activity. Our findings provide mechanistic guidelines for the rational design of HOR catalysts with high activity.

17.
Molecules ; 28(13)2023 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-37446834

RESUMO

Euphorbia fischeriana has a long-standing history of use in traditional medicine for the treatment of tuberculosis diseases. However, the plant's therapeutic potential extends beyond this specific ailment. The present study aimed to investigate the antioxidant properties of Euphorbia fischeriana and lay the groundwork for further research on its potential therapeutic applications. Phytochemical tests were performed on the plant, and 11 types of phytochemicals were identified. Ultraviolet-visible spectrophotometry was used to evaluate the active components and antioxidant properties of eight different solvent extracts, ultimately selecting acetone extract for further research. UHPLC-ESI-Q-TOF-MS identified 43 compounds in the acetone extract, and chemical calculations were used to isolate those with high content and antioxidant activity. Three stability experiments confirmed the extract's stability, while cell viability and oral acute toxicity studies demonstrated its relatively low toxicity. In rats, the acetone extract showed significant protective effects against D-galactosamine-induced liver damage through histopathological examination and biochemical analysis. These results suggest that Euphorbia fischeriana's acetone extract has potential in treating diseases related to oxidative imbalances. Therefore, this study highlights the plant's potential therapeutic applications while providing insight into its antioxidant properties.


Assuntos
Antioxidantes , Euphorbia , Ratos , Animais , Antioxidantes/farmacologia , Antioxidantes/química , Extratos Vegetais/química , Euphorbia/química , Acetona , Compostos Fitoquímicos/farmacologia
18.
Angew Chem Int Ed Engl ; 62(3): e202214959, 2023 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-36307930

RESUMO

The renewable-electricity-driven CO2 reduction to formic acid would contribute to establishing a carbon-neutral society. The current catalyst suffers from limited activity and stability under high selectivity and the ambiguous nature of active sites. Herein, we report a powerful Bi2 S3 -derived catalyst that demonstrates a current density of 2.0 A cm-2 with a formate Faradaic efficiency of 93 % at -0.95 V versus the reversible hydrogen electrode. The energy conversion efficiency and single-pass yield of formate reach 80 % and 67 %, respectively, and the durability reaches 100 h at an industrial-relevant current density. Pure formic acid with a concentration of 3.5 mol L-1 has been produced continuously. Our operando spectroscopic and theoretical studies reveal the dynamic evolution of the catalyst into a nanocomposite composed of Bi0 clusters and Bi2 O2 CO3 nanosheets and the pivotal role of Bi0 -Bi2 O2 CO3 interface in CO2 activation and conversion.

19.
Phys Chem Chem Phys ; 24(38): 23301-23308, 2022 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-36165277

RESUMO

Orbital interactions between adsorbed molecules and the underlying metal surfaces play critical roles in a wide range of surface and interfacial processes. Establishing a correlation between an experimental observable (e.g., vibrational frequency shift of the adsorbed molecule) and the orbital interactions is of vital importance. Herein, theoretical calculations are used to investigate the vibrational frequency shift of phenyl isocyanide molecules as a probe molecule adsorbed on mono- and bi-layer Pt and Pd covered Au(111) surfaces and Pd2Au4 and Pt2Au4 clusters. By analyzing the density of states (DOS) of the adsorption system, we show that the orbital overlap area of d electronic DOS with a molecular σ or π* orbital, particularly their ratio (Rd-σ/d-π*), can be a meaningful descriptor to explain the frequency shift of the CN moiety. This hypothesis has been verified by simulations for phenyl isocyanide with electron donating NH2- and withdrawing CF3- substituent groups, formonitrile and carbon monoxide. Quasi-linear dependence of the frequency shift on Rd-σ/d-π* is observed for both the red and blue shift regions. Our findings build up on previous notions of electronic interactions, which will provide a more quantitative and solid footing to understand and analyze the frequency shift of adsorbed molecules on metal surfaces and the related electronic interactions and catalytic properties.

20.
Angew Chem Int Ed Engl ; 61(25): e202203511, 2022 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-35383412

RESUMO

Identification of different mitochondrial reactive oxygen species (ROS) simultaneously in living cells is vital for understanding the critical roles of different ROS in biological processes. To date, it remains a great challenge to develop ROS probes for direct and simultaneous identification of multiple ROS with high specificity. Herein, we report a SERS-borrowing-strategy-based nanoprobe (Au@Pt core-shell nanoparticles) for simultaneous and direct identification of different ROS by their distinct Raman fingerprints. Isotope substitution experiments and DFT calculations confirmed the ability of Au@Pt nanoprobe to capture and identify different mitochondrial ROS (i.e. ⋅OOH, H2 O2 , and ⋅OH). When functionalized with triphenylphosphine (TPP), the Au@Pt-TPP nanoprobe located to mitochondria and detected multiple ROS simultaneously in living cells under oxidative stimulation. Our method offers a new tool for the study of the functions of various ROS in biological processes.


Assuntos
Nanopartículas Metálicas , Nanopartículas , Ouro , Mitocôndrias , Espécies Reativas de Oxigênio , Análise Espectral Raman/métodos
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