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1.
Small ; 20(23): e2309814, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38155521

RESUMO

Active compounds based on LDH (ternary layered double hydroxide) are considered the perfect supercapacitor electrode materials on account of their superior electrochemical qualities and distinct structural characteristics, and flexible supercapacitors are an ideal option as an energy source for wearable electronics. However, the prevalent aggregation effect of LDH materials results in significantly compromised actual specific capacitance, which limits its broad practical applications. In this research, a 3D eggshell-like interconnected porous carbon (IPC) framework with confinement and isolation capability is designed and synthesized by using glucose as the carbon source to disperse the LDH active material and enhance the conductivity of the composite material. Second, by constructing NiCoMn-LDH nanocage structure based on ZIF-67 (zeolitic imidazolate framework-67) at the nanometer scale the obtained IPC/NiCoMn-LDH electrode material can expose more active sites, which allows to achieve excellent specific capacitance (2236 F g-1/ 310.6 mAh g-1 at 1 A g-1), good rate as well as the desired cycle stability (85.9% of the initial capacitance upon 5000 cycles test). The constructed IPC/NiCoMn-LDH//IPC ASC (asymmetric supercapacitor) exhibits superior capacitive property (135 F g-1/60.1 mAh g-1 at 0.5 A g-1) as well as desired energy density (40 Wh kg-1 at 800 W kg-1).

2.
Small ; 20(6): e2305288, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37775328

RESUMO

Clever and rational design of structural hierarchy, along with precise component adjustment, holds profound significance for the construction of high-performance supercapacitor electrode materials. In this study, a binder-free self-supported CCO@N0.5 C0.5 OH/NF cathode material is constructed with hierarchical hetero-core-shell honeycomb nanostructure by first growing CuCo2 O4 (CCO) nanopin arrays uniformly on highly conductive nickel foam (NF) substrate, and then anchoring Ni0.5 Co0.5 (OH)2 (N0.5 C0.5 OH) bimetallic hydroxide nanosheet arrays on the CCO nanopin arrays by adjusting the molar ratio of Ni(OH)2 and Co(OH)2 . The constructed CCO@N0.5 C0.5 OH/NF electrode material showcases a wealth of multivalent metal ions and mesopores, along with good electrical conductivity, excellent electrochemical reaction rates, and robust long-term performance (capacitance retention rate of 87.2%). The CCO@N0.5 C0.5 OH/NF electrode, benefiting from the hierarchical structure of the material and the exceptional synergy between multiple components, demonstrates an excellent specific capacitance (2553.6 F g-1 at 1 A g-1 ). Furthermore, the assembled asymmetric CCO@N0.5 C0.5 OH/NF//AC/NF supercapacitor demonstrates a high energy density (70.1 Wh kg-1 at 850 W kg-1 ), and maintains robust capacitance cycling stability performance (83.7%) after undergoing 10 000 successive charges and discharges. It is noteworthy that the assembled supercapacitor exhibits an operating voltage (1.7 V) that is well above the theoretical value (1.5 V).

3.
Exp Cell Res ; 433(1): 113804, 2023 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-37806378

RESUMO

Alcohol dehydrogenase 1 (ADH1) is an alcohol-oxidizing enzyme with poorlydefined biology. Here we report that ADH1 is highly expressed in kidneys of mice with lethal endotoxemia and is transcriptionally upregulated in tubular cells by lipopolysaccharide (LPS) stimuli through TLR4/NF-κB cascade. The Adh1 knockout (Adh1KO) mice with lethal endotoxemia displayed increased susceptibility to acute kidney injury (AKI) but not systemic inflammatory response. Adh1KO mice develop more severe tubular cell apoptosis in comparison to Adh1 wild-type (Adh1WT) mice during course of lethal endotoxemia. ADH1 deficiency facilitates the LPS-induced tubular cell apoptosis in a caspase-dependent manner. Mechanistically, ADH1 deficiency dampens tubular mitophagy that relies on PINK1-Parkin pathway characterized by the reduced membrane potential, reactive oxygen species (ROS) and release of fragmented mtDNA to cytosol. Kidney-specific overexpression of PINK1 and Parkin by adeno-associated viral vector 9 (AAV9) delivery ameliorates AKI exacerbation in Adh1KO mice with lethal endotoxemia. Our study supports the notion that ADH1 is critical for blockade of tubular apoptosis mediated by mitophagy, allowing the rapid identification and targeting of alcohol-metabolic route applicable to septic AKI.

4.
Small ; 19(43): e2303043, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37376807

RESUMO

Flexible energy storage device is one of the most critical components as power source for wearable electronics. The emergence of MXenes, a growing family of 2D nanomaterials, has demonstrated a brand-new possibility for flexible energy storage. However, the fabrication of MXene films with satisfactory mechanical, electrical, and electrochemical reliabilities remains challenging due to the weak interlayer interactions and self-restacking of MXene sheets. Sequential bridging of polydopamine/polyethyleneimine-functionalized (PDA/PEI)-coated MXene sheets to induce synergistically covalent and hydrogen binding connections of MXene-based films is demonstrated here. By interrupting self-hydrogen bonding and π-π stacking interactions, the introduction of long-chain PEI can not only inhibit the massive aggregation of PDA, but also improve the continuity of the interconnection network of PDA/PEI between MXene layers. Hence, the as-prepared MXene/PDA/PEI composite film displays high mechanical strength (≈366 MPa) which achieves 12-fold improvement compared with pure MXene film, as well as superior energy storage capability (≈454 F g-1  at 5 mV s-1 ) and rate performance of ≈48% at 10 000 mV s-1 . This modulation of inserted polymer between MXene layers can provide an avenue for assembling high performance MXene films, and can even be extended to the fabrication of other 2D platelets for varied applications.

5.
Small ; 19(28): e2301627, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36974604

RESUMO

The ambient electrochemical N2 reduction reaction (NRR) is a future approach for the artificial NH3 synthesis to overcome the problems of high-energy consumption and environmental pollution by Haber-Bosch technology. However, the challenge of N2 activation on a catalyst surface and the competitive hydrogen evolution reaction make the current NRR unsatisfied. Herein, this work demonstrates that NbB2 nanoflakes (NFs) exhibit excellent selectivity and durability in NRR, which produces NH3 with a production rate of 30.5 µg h-1 mgcat -1 and a super-high Faraday efficiency (FE) of 40.2%. The high-selective NH3 production is attributed to the large amount of active B vacancies on the surface of NbB2 NFs. Density functional theory calculations suggest that the multiple atomic adsorption of N2 on both unsaturated Nb and B atoms results in a significantly stretched N2 molecule. The weakened NN triple bonds are easier to be broken for a biased NH3 production. The diatomic catalysis is a future approach for NRR as it shows a special N2 adsorption mode that can be well engineered.

6.
Opt Lett ; 48(4): 924-927, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36790976

RESUMO

In this paper, we research the temperature stability of silicon-based ring resonator thermometers utilizing the Pound-Drever-Hall (PDH) technique. A slight temperature fluctuation of 12.2 mK in 200 s was experimentally detected by immersing the sensor in the triple point of water (TPW) system with ultrahigh precision. Additionally, factors that affect temperature stability, including fundamental thermal noise, laser frequency drift, and power fluctuation were analyzed and calculated theoretically. This shows high consistency with experimental results. Moreover, it is proved that the laser drift can be suppressed from 11.3 pm to 0.013 pm with the developed experimental system based on the PDH technique. The silicon-based ring resonator as a potential platform for precise temperature monitoring is proved based on this work.

7.
Langmuir ; 39(38): 13571-13578, 2023 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-37696114

RESUMO

Occlusal force is an important parameter for evaluating the function of the occlusal system. Traditional occlusal forces can only be measured qualitatively. Here, we report a flexible piezoresistive pressure sensor with high sensitivity and a wide measurement range for in situ occlusal force measurements through the articulating paper. The sensing layer of the flexible piezoresistive sensor is a 3D porous MXene composite aerogel, which is fabricated by vacuum freezing. The MXene piezoresistive sensor is composed of the interdigital electrodes, the sensing layer, the PI encapsulation layer, and an articulating paper encapsulation layer. The sensor shows perfect performance with high sensitivity (210.21 kPa-1), wide measurement range (∼420 kPa), and a fast response time (123 ms response time, 163 ms recovery time). The amplitude of the occlusal force, which varied with time, can be observed on the mobile phone through the wireless system with the Bluetooth module. This technique has broad application prospects in oral health. In this work, we propose a simple method and a new idea for manufacturing high-performance wearable bioelectronic sensors.


Assuntos
Força de Mordida , Titânio , Eletrodos , Porosidade
8.
Langmuir ; 39(30): 10692-10700, 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37467158

RESUMO

Indoor gaseous formaldehyde is the main environmental pollutant that can cause fatal threats to human health. A number of physical and chemical methods have been developed to tackle this issue. However, the existing methods are still unsatisfactory to meet the requirement of sustainable development owing to the flaws of low efficiency and reversible or second pollution. Herein, a chemical method based on a nucleophilic reaction between hydrazine and aldehyde that generates the only by-product of H2O is designed for the removal of formaldehyde. 1-Pyrenebutyric hydrazide was synthesized by a simple esterification reaction and then self-assembled on reduced graphene oxide (rGO) with a large surface area by forming π-π stacking to obtain a composite for chemical removal of gaseous formaldehyde under ambient conditions. In a practical test, the formaldehyde removal rate could reach 91% of the theoretical value, which meets the requirement for commercial formaldehyde removal applications. After 10 times recycling, the formaldehyde removal rate still remains as high as 85%. Moreover, the composite could be regenerated in weak acidic media, which greatly reduce the manufacturing cost in practical applications.

9.
BMC Infect Dis ; 23(1): 709, 2023 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-37864200

RESUMO

BACKGROUND: The rapid global emergence and spread of carbapenem-resistant Gram-negative bacilli (CR-GNB) is recognized as a major public health concern, and there are currently few effective treatments for CR-GNB infection. The aim of this study was to investigate the clinical characteristics and outcomes of patients with CR-GNB infections treated with ceftazidime/avibactam (CAZ/AVI) combined with colistin from October 2019 to February 2023 in China. METHODS: A total of 31 patients with CR-GNB infections were retrospectively identified using the electronic medical record system of Zhejiang Provincial People's Hospital. RESULTS: Thirty-one patients were treated with CAZ/AVI combined with colistin. Respiratory tract infections (87%) were most common. The common drug-resistant bacteria encompass Klebsiella pneumonia (54.8%), Acinetobacter baumannii (29.0%), and Pseudomonas aeruginosa (16.1%). The 30-day mortality rate was 29.0%, and the 7-day microbial clearance rate was 64.5%. The inflammatory marker CRP changes, but not PCT and WBC, were statistically significant on days 7 and 14 after combination therapy. There were seven patients developing acute renal injury (AKI) after combination therapy and treating with continuous renal replacement therapy (CRRT). Two patients developed diarrhea. CONCLUSION: The combination of CAZ/AVI and colistin has potential efficacy in patients with CR-GNB infection, but more studies are needed to determine whether it can reduce 30-day mortality rates and increase 7-day microbial clearance. At the same time, the adverse reactions of combination therapy should not be ignored.


Assuntos
Ceftazidima , Colistina , Humanos , Ceftazidima/uso terapêutico , Ceftazidima/farmacologia , Colistina/uso terapêutico , Colistina/farmacologia , Carbapenêmicos/uso terapêutico , Carbapenêmicos/farmacologia , Antibacterianos/uso terapêutico , Antibacterianos/farmacologia , Estudos Retrospectivos , Bactérias Gram-Negativas
10.
Macromol Rapid Commun ; 44(2): e2200629, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36200608

RESUMO

Herein, the fabrication of reduced graphene oxide (RGO)-templated polymer composites for chemical removal of gaseous formaldehyde under ambient conditions is presented. The chemical removal of formaldehyde is achieved by a nucleophilic addition reaction between formaldehyde and aminooxy groups on the polymer chain ends to form the oxime bonds with the only byproduct of H2 O. RGO is essential since it not only has an ultralarge surface area but also can act as a perfect template for immobilizing pyrene-terminated and aminooxy-functionalized polymers via strong π-π stacking interactions, while melamine foam provides a three-dimensional skeleton for loading RGO/polymer composites to afford a porous 3D structure for efficient formaldehyde removal. Since the oxime bond can be cleaved into aminooxy group in acidic media, the RGO/polymer composite can be regenerated for repeatable usage, which shows an excellent performance of adsorbing 14 mg of formaldehyde by 100 mg of the polymer at ambient condition.


Assuntos
Carbono , Polímeros , Polímeros/química , Porosidade , Temperatura , Formaldeído/química , Oximas
11.
Ecotoxicol Environ Saf ; 249: 114421, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36529044

RESUMO

Previous studies have determined that magnesium (Mg) in appropriate concentrations prevents plants from suffering from abiotic stress. To better understand the mechanism of Mg alleviation of aluminum (Al) stress in apple, we investigated the effect of Mg on plant growth, photosynthetic fluorescence, antioxidant system, and carbon (C) and nitrogen (N) metabolism of apple seedlings under Al toxicity (1.5 mmol/L) via a hydroponic experiment. Al stress induced the production of reactive oxygen in the leaves and roots and reduced the total dry weight (DW) by 52.37 % after 20 days of treatment relative to plants grown without Al, due to hindered photosynthesis and alterations in C and N metabolism. By contrast, total DW decreased by only 11.07 % in the Mg-treated plants under Al stress. Supplementation with 3.0 mmol/L Mg in the Al treatment decreased Al accumulation in the apple plants and reduced Al-induced oxidative damage by enhancing the activity of antioxidant enzymes (superoxide dismutase, catalase, and peroxidase) and reducing the production of H2O2 and malondialdehyde (MDA). Under Al stress, the Mg-treated plants showed a 46.17 % higher photosynthetic rate than the non-treated plants. Supplementation with Mg significantly increased the sucrose content by increasing sucrose synthase (SS) and sucrose-phosphate synthase (SPS) activities. Moreover, Mg facilitated the transport of 13C-carbohydrates from the leaves to roots. Regarding N metabolism, the nitrate reductase (NR), glutamine synthase (GS), and glutamate synthase (GOGAT) activities in the roots and leaves of the Mg-treated plants were significantly higher than those of the non-treated plants under Al stress. Compared with the non-treated plants under Al stress, the Mg-treated plants exhibited a significantly high level of NO3- and soluble protein content in the leaves, roots, and stems, but a low level of free amino acids. Furthermore, Mg significantly improved nitrogen accumulation and enhanced the transport of 15N from the roots to leaves. Overall, our results revealed that Mg alleviates Al-induced growth inhibition by enhancing antioxidant capacity and C-N metabolism in apple seedlings.


Assuntos
Antioxidantes , Malus , Antioxidantes/farmacologia , Antioxidantes/metabolismo , Plântula , Alumínio/toxicidade , Alumínio/metabolismo , Magnésio/farmacologia , Magnésio/metabolismo , Malus/metabolismo , Carbono/metabolismo , Peróxido de Hidrogênio/metabolismo , Nitrogênio/metabolismo , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo
12.
Sensors (Basel) ; 23(18)2023 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-37765945

RESUMO

In this paper, we present a soft and moisturizing film electrode based on bacterial cellulose and Ag/AgCl conductive cloth as a potential replacement for gel electrode patches in electroencephalogram (EEG) recording. The electrode materials are entirely flexible, and the bacterial cellulose membrane facilitates convenient adherence to the skin. EEG signals are transmitted from the skin to the bacterial cellulose first and then transferred to the Ag/AgCl conductive cloth connected to the amplifier. The water in the bacterial cellulose moisturizes the skin continuously, reducing the contact impedance to less than 10 kΩ, which is lower than commercial gel electrode patches. The contact impedance and equivalent circuits indicate that the bacterial cellulose electrode effectively reduces skin impedance. Moreover, the bacterial cellulose electrode exhibits lower noise than the gel electrode patch. The bacterial cellulose electrode has demonstrated success in collecting α rhythms. When recording EEG signals, the bacterial cellulose electrode and gel electrode have an average coherence of 0.86, indicating that they have similar performance across different EEG bands. Compared with current mainstream conductive rubber dry electrodes, gel electrodes, and conductive cloth electrodes, the bacterial cellulose electrode has obvious advantages in terms of contact impedance. The bacterial cellulose electrode does not cause skin discomfort after long-term recording, making it more suitable for applications with strict requirements for skin affinity than gel electrode patches.


Assuntos
Celulose , Testa , Eletroencefalografia , Condutividade Elétrica , Impedância Elétrica , Eletrodos
13.
Nano Lett ; 22(4): 1769-1777, 2022 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-35156826

RESUMO

Circularly polarized light carries spin angular momentum, so it can exert an optical torque on the polarization-anisotropic particle by the spin momentum transfer. Here, we show that giant positive and negative optical torques on Mie-resonant (gain) particles arise from the emergence of superhybrid modes with magnetic multipoles and electric toroidal moments, excited by linearly polarized beams. Anomalous positive and negative torques on particles (doped with judicious amount of dye molecules) are over 800 and 200 times larger than the ordinary lossy counterparts, respectively. Meanwhile, a rotational motor can be configured by switching the s- and p-polarized beams, exhibiting opposite optical torques. These giant and reversed optical torques are unveiled for the first time in the scattering spectrum, paving another avenue toward exploring unprecedented physics of hybrid and superhybrid multipoles in metaoptics and optical manipulations.

14.
J Am Chem Soc ; 144(2): 995-1005, 2022 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-35005982

RESUMO

Metal naphthalocyanines (MNcs) were demonstrated to be efficient photocatalysts to activate photoinduced electron-transfer reversible addition-fragmentation chain transfer (PET-RAFT) polymerization, enabling well-controlled polymerization of (meth)acrylates under near-infrared (λ = 780 nm) light. Owing to their lower redox potential compared to previously explored photocatalysts, the activation of trithiocarbonate RAFT agents exhibited a unique selectivity that was dependent on the nature of the R group. Specifically, MNcs were capable in activating tertiary R group trithiocarbonates, whereas no activation of the trithiocarbonate possessing a secondary R group was observed. The combination of density functional theory calculations and experimental studies have revealed new mechanistic insights into the factors governing a PET-RAFT mechanism and explained this unique selectivity of MNcs toward tertiary carbon trithiocarbonates. Interestingly, by increasing the reaction temperature moderately (i.e., ∼15 °C), the energy barrier prohibiting the photoactivation of the trithiocarbonate with a secondary R group was overcome, enabling their successful activation.

15.
Phys Rev Lett ; 129(5): 053902, 2022 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-35960581

RESUMO

Elliptically polarized light waves carry the spin angular momentum (SAM), so they can exert optical torques on nanoparticles. Usually, the rotation follows the same direction as the SAM due to momentum conservation. It is counterintuitive to observe the reversal of optical torque acting on an ordinary dielectric nanoparticle illuminated by an elliptically or circularly polarized light wave. Here, we demonstrate that negative optical torques, which are opposite to the direction of SAM, can ubiquitously emerge when elliptically polarized light waves are impinged on dielectric nanoparticles obliquely. Intriguingly, the rotation can be switched between clockwise and counterclockwise directions by controlling the incident angle of light. Our study suggests a new playground to harness polarization-dependent optical force and torque for advancing optical manipulations.

16.
Chemistry ; 28(51): e202200683, 2022 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-35722766

RESUMO

Combining the self-sacrifice of a highly crystalline substance to design a multistep chain reaction towards ultrathin active-layer construction for high-performance water splitting with atmospheric-temperature conditions and an environmentally benign aqueous environment is extremely intriguing and full of challenges. Here, taking cobalt carbonate hydroxides (CCHs) as the initial crystalline material, we choose the Lewis acid metal salt of Fe(NO3 )3 to induce an aqueous-phase chain reaction generating free CO3 2- ions with subsequent instant FeCO3 hydrolysis. The resultant ultrathin (∼5 nm) amorphous Fe-based hydroxide layer on CCH results in considerable activity in catalyzing the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), yielding 10/50 mA ⋅ cm-2 at overpotentials of 230/266.5 mV for OER and 72.5/197.5 mV for HER. The catalysts can operate constantly in 1.0 M KOH over 48 and 45 h for the OER and HER, respectively. For bifunctional catalysis for alkaline electrolyzer assembly, a cell voltage as low as 1.53 V was necessary to yield 10 mA cm-2 (1.7 V at 50 mA cm-2 ). This work rationally builds high-efficiency electrochemical bifunctional water-splitting catalysts and offers a trial in establishing a controllable nanolevel ultrathin lattice disorder layer through an atmospheric-temperature chemical route.

17.
BMC Infect Dis ; 22(1): 771, 2022 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-36195855

RESUMO

BACKGROUND AND OBJECTIVES: Bloodstream infection (BSI) is a life-threatening condition in critically ill patients, but pathogen quantification techniques during treatment are laborious. This study aimed to explore the impact of monitoring pathogen DNA load changes and polymicrobial infection in blood by droplet digital polymerase chain reaction (ddPCR) on the prognosis of patients with BSIs. METHODS: This prospective case series study was conducted in the general intensive care unit of the Zhejiang Provincial People's Hospital and included patients with BSIs from May 2020 to January 2021. Pathogens DNA load and presence of polymicrobial BSIs were dynamically monitored by ddPCR. RESULTS: Sixteen patients with BSIs proven by blood culture were recruited (87.5% men; mean age, 69.3 ± 13.7 years). All pathogens identified by blood culture were Gram-negative bacteria, among which seven were multidrug-resistant strains. The 28-day mortality rate was 62.5%. Compared to the 28-day survivors, the non-survivors were older (P = 0.04), had higher pathogen DNA load on the second (day 3-4) and third (day 6-7) ddPCR assay (P < 0.01 in both cases). In addition, the changes of pathogen DNA load in the 28-day survivors had a downward trend in the first three ddPCR assay, whereas stable load or an upward trend was observed in the 28-day non-survivors. Moreover, the number of pathogen species in patients with BSIs in the 28-day survivors decreased during the period of effective antibiotic treatment. CONCLUSION: The changes of pathogen DNA load and species monitored in blood by ddPCR may be used to determine antibiotic efficacy and make a more accurate prognostic assessment in patients with BSIs.


Assuntos
Bacteriemia , Sepse , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/uso terapêutico , Bacteriemia/diagnóstico , Bacteriemia/tratamento farmacológico , Bacteriemia/microbiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase/métodos , Estudos Prospectivos , Sepse/tratamento farmacológico
18.
J Am Chem Soc ; 143(26): 9781-9790, 2021 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-34164979

RESUMO

The real-time observation of chemical bond formation at the single-molecule level is one of the great challenges in the fields of organic and biomolecular chemistry. Valuable information can be gleaned that is not accessible using ensemble-average measurements. Although remarkably sophisticated techniques for monitoring chemical reactions have been developed, the ability to detect the specific formation of a chemical bond in situ at the single-molecule level has remained an elusive goal. Amide bonds are routinely formed from the aminolysis of N-hydroxysuccinimide (NHS) esters by primary amines, and the protocol is widely used for the synthesis, cross-linking, and labeling of peptides and proteins. Herein, a plasmonic nanocavity was applied to study aminolysis reaction for amide bond formation, which was initiated by single nanoparticle collision events between suitably functionalized free-moving gold nanoparticles and a gold nanoelectrode in an aqueous buffer. By means of simultaneous surface enhanced Raman spectroscopy (SERS) and single-entity electrochemistry (EC) measurements, we have probed the dynamic evolution of amide bond formation in the aminolysis reaction with 10 s of millisecond time resolution. Hence, we demonstrate that single-entity EC-SERS is a valuable and sensitive technique by which chemical reactions can be studied at the single-molecule level.

19.
Opt Lett ; 46(2): 162-165, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33448978

RESUMO

The realization of bound states in the continuum (BICs) in optical systems has been relying mainly on symmetry breaking. In contrast, another mechanism, known as resonance-trapped (or Friedrich-Wintgen) scenario, has been reported in the limited scope of dielectric resonant inclusions or at off-Γ points. In this Letter, we demonstrate that the coupling coefficient between two coplanar metallic split-ring resonators can be tuned to satisfy the Friedrich-Wintgen BIC condition with normal terahertz (THz) incidence when metals are modeled as perfect electric conductors. Temporal coupled-mode theory is applied to validate the results. Experimentally, a BIC-induced cloaking effect has been observed, owing to the intrinsic dissipation loss of the constitutive materials. Our findings suggest an alternative strategy to construct BICs in metallic metasurfaces apart from conventional symmetry-breaking methods.

20.
Chemistry ; 27(69): 17402-17411, 2021 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-34648217

RESUMO

The excellent electrical conductivity of graphene is due to its highly-conjugated structures. Manipulation of the electronic and mechanical properties of graphene can be achieved by controlling the destruction of its in-sheet conjugation system. Herein, we report the preparation of CoCeSx -SA@BPMW@RGO through π-π stacking interactions at the molecular level. In this study, sodium alginate was reacted with Co2+ and Ce3+ , and the composite was loaded onto a graphene surface. The graphene sheets were prepared using a bi-pyrene terminated molecular wire (BPMW) to avoid re-stacking of the grapheme sheets, thereby forming nanoscale spaces between sheets. The angle between the BPMW coplanar pyrene group and the phenyl group was 33.2°, and the graphene layer is supported in an oblique direction. Finally, a three-dimensional porous composite was obtained after annealing and vulcanization. The obtained CoCeSx -SA@BPMW@RGO exhibited excellent electrical conductivity and remarkable cycle stability. When the current density was 1 A g-1 , its specific capacitance was as high as 1004 F g-1 . BPMW modifies graphene through the synergistic effect of π-π stacking interaction and special structure to obtain excellent electrochemical performance. Moreover, a solid-state asymmetric supercapacitor device was fabricated based on the synthesized CoCeSx -SA@BPMW@RGO hybrid, which exhibited a power density of 979 W kg-1 at an energy density of 23.96 Wh kg-1 .

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