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1.
Brain Res ; 1841: 149085, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38876320

RESUMO

As a cutting-edge technology of connecting biological brain and external devices, brain-computer interface (BCI) exhibits promising applications on extensive fields such as medical and military. As for the disable individuals with four limbs losing the motor functions, it is a potential treatment way to drive mechanical equipments by the means of non-invasive BCI, which is badly depended on the accuracy of the decoded electroencephalogram (EEG) singles. In this study, an explanatory convolutional neural network namely EEGNet based on SimAM attention module was proposed to enhance the accuracy of decoding the EEG singles of index and thumb fingers for both left and right hand using sensory motor rhythm (SMR). An average classification accuracy of 72.91% the data of eight healthy subjects was obtained, which were captured from the one second before finger movement to two seconds after action. Furthermore, the character of event-related desynchronization (ERD) and event related synchronization (ERS) of index and thumb fingers was also studied in this study. These findings have significant importance for controlling external devices or other rehabilitation equipment using BCI in a fine way.

2.
J Colloid Interface Sci ; 669: 965-974, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38759595

RESUMO

Efficient oxygen evolution reaction (OER) is vital for water electrolysis and advanced hydrogen energy production. However, the sluggish kinetics of this reaction require significant overpotentials, leading to high energy consumption. Therefore, developing OER electrocatalysts with exceptional performance and long-term durability is crucial for enhancing the energy efficiency and cost-effectiveness of the hydrogen production process. In this research, novel FeOOH/Co9S8 catalysts were prepared through a two-step hydrothermal reaction followed by one-step electrodeposition on nickel foam for an alkaline OER. The as-obtained catalysts possessed abundant non-homogeneous interfaces between FeOOH and Co9S8 nanosheets, conducive to optimized coordination environments of Fe and Co sites by redistributing interfacial charges. This synergy strengthened the chemisorption of oxygenated intermediates, leading to accelerated reaction kinetics, abundant active sites, and enhanced OER performance. The optimized electrocatalyst FeOOH/Co9S8-15 achieved a current density of 10 mA cm-2 at an overpotential of 248 mV and good stability for over 140 h. This study presents a novel approach for producing compelling and durable alkaline dielectric OER electrocatalysts, which will be helpful in the future manufacturing of advanced energy devices.

3.
Sci Total Environ ; 919: 170802, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38342469

RESUMO

Nitrous oxide (N2O) and nitrogen oxides (NOx) (i.e., nitric oxide (NO) and nitrogen dioxide (NO2)), which could be produced in wastewater treatment process and result in greenhouse effect and atmospheric pollution, respectively, have been studied limitedly in their emission characteristics and transformation mechanisms. In this study, intelligent oxygen regulation was applied in anoxic/oxic wastewater treatment process (I-A/O), and its effects on regulating NOx and N2O transformations were extensively explored by comparing it with conventional A/O process (C-A/O). Results showed that the average emission amounts of N2O and NOx in I-A/O were 7.45 ± 0.66 mg and 1.88 ± 0.10 mg, respectively. Satisfactory reduction of N2O by 29.28 %-45.08 % was achieved in I-A/O compared to that of C-A/O, but together with increased NOx emission by 83.19 %-120.57 %. Pearson correlation and transcriptional analysis suggested that NO2--N reduction in the anoxic phase dominated N2O production, while no significant N2O production in the oxic phase was found. Hence, the reduced N2O production in I-A/O was mainly attributed to its efficient denitrification process. On the other hand, both the anoxic and oxic phases played important roles in NO production. More importantly, sufficient oxygen in I-A/O promoted the ammonia oxidation process, resulting in higher NO emission in I-A/O in the oxic phase. The imbalance in NO and N2O emissions was then amplified by the NOR enzyme, which mediates the conversion of NO to N2O in both the anoxic and oxic phases. Besides, carbon emission reduction by 31.32 %-36.50 % was obtained in I-A/O due to aeration consumption savings and greenhouse gas emissions reduction compared to C-A/O. Overall, intelligent oxygen regulation optimized the nitrogen transformation and achieved carbon emission reduction in A/O process, but special attention should be paid to the associated risk caused by increased NO emissions.

4.
Angew Chem Int Ed Engl ; 63(6): e202317022, 2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38151463

RESUMO

Triggering rapid reconstruction reactions holds the potential to approach the theoretical limits of the oxygen evolution reaction (OER), and spin state manipulation has shown great promise in this regard. In this study, the transition of Fe spin states from low to high was successfully achieved by adjusting the surface electronic structure of pentlandite. In situ characterization and kinetic simulations confirmed that the high-spin state of Fe promoted the accumulation of OH- on the surface and accelerated electron transfer, thereby enhancing the kinetics of the reconstruction reaction. Furthermore, theoretical calculations revealed that the lower d-band center of high-spin Fe optimized the adsorption of active intermediates, thereby enhancing the reconstruction kinetics. Remarkably, pentlandites with high-spin Fe exhibited ultra-low overpotential (245 mV @ 10 mA cm-2 ) and excellent stability. These findings provided new insights for the design and fabrication of highly active OER electrocatalysts.

5.
J Colloid Interface Sci ; 644: 64-72, 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37094473

RESUMO

Cobalt hydroxylfluoride (CoOHF) is an emerging supercapacitor material. However, it remains highly challenging to effectively enhance the performance of CoOHF, which is limited by its poor electron and ion transport ability. In this study, the intrinsic structure of CoOHF was optimized through Fe doping (CoOHF-xFe, where x represents the Fe/Co feeding ratio). As indicated by the experimental and theoretical calculation results, the incorporation of Fe effectively enhances the intrinsic conductivity of CoOHF and optimizes its surface ion adsorption capacity. Moreover, since the radius of Fe is slightly larger than that of Co, the space between the crystal planes of CoOHF increases to a certain extent, and the ability to store ions is consequently enhanced. The optimized CoOHF-0.06Fe sample exhibits the maximum specific capacitance (385.8 F g-1). The asymmetric supercapacitor with activated carbon achieves a high energy density of 37.2 Wh kg-1 at a power density of 1600 W kg-1, and a full hydrolysis pool is successfully driven by the device, indicating great application potential. This study lays a solid basis for the application of hydroxylfluoride to a novel generation of supercapacitors.

6.
J Colloid Interface Sci ; 640: 600-609, 2023 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-36878077

RESUMO

Rapid preparation strategies of carbon-based materials with a high power density and energy density are crucial for the large-scale application of carbon materials in energy storage. However, achieving these goals quickly and efficiently remains challenging. Herein, the rapid redox reaction of concentrated H2SO4 and sucrose was employed as a means to destroy the perfect carbon lattice to form defects and insert large numbers of heteroatoms into the defects to rapidly form electron-ion conjugated sites of carbon materials at room temperature. Among prepared samples, CS-800-2 showed an excellent electrochemical performance (377.7 F g-1, 1 A g-1) and high energy density in 1 M H2SO4 electrolyte owing to its large specific surface area and a significant number of electron-ion conjugated sites. Additionally, CS-800-2 exhibited desirable energy storage performance in other aqueous electrolytes containing various metal ions. The theoretical calculation results revealed increased charge density near the carbon lattice defects, and the presence of heteroatoms effectively reduced the adsorption energy of carbon materials toward cations. Accordingly, the constructed "electron-ion" conjugated sites comprising defects and heteroatoms on the super-large surface of carbon-based materials accelerated the pseudo-capacitance reactions on the material surface, thereby greatly enhancing the energy density of carbon-based materials without sacrificing power density. In sum, a fresh theoretical perspective for constructing new carbon-based energy storage materials was provided, promising for future development of high-performance energy storage materials and devices.

7.
J Colloid Interface Sci ; 630(Pt A): 618-628, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36272216

RESUMO

The low energy density issue raises serious concerns for the large-scale application of supercapacitors. However, the development and utilization of new electrode materials with a high specific capacity to improve the energy density of supercapacitors remain challenging. Herein, an LaMnO3@NiCo2O4/carbon cloth (LMO@NCO/CC) composed of a multilayer flower-like nanochip array is prepared for the first time using an efficient electrodeposition method. This novel structure exploits the high conductivity of LaMnO3/carbon cloth (LMO@CC) to provide an efficient electron transport path for the outer layer of the NiCo2O4/carbon cloth (NCO@CC) nanoarrays, broadening the potential window. Due to the unique nanostructure configuration and the strong synergistic effect of the developed LMO@NCO/CC, the prepared electrodes show excellent supercapacitor performance. At a current density of 1 A g-1, LMO@NCO/CC has a higher specific capacitance value of 942 F g-1. The application value is extended through the fabrication of asymmetric supercapacitors with a maximum energy density of 49 Wh kg-1 and excellent cycle stability (the initial capacitance value remains 106 % after 10,000 cycles of charging and discharging at a high current density of 10 A g-1). Our work paves the way for the development of next-generation electrode materials for high-performance supercapacitors.

8.
J Colloid Interface Sci ; 617: 430-441, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35286999

RESUMO

LaNiO3 and NiO are promising materials for supercapacitor applications. However, it is still challenging to design special structures based on these materials to improve the electrochemical performances of supercapacitor electrodes. In this work, a two-step method with low cost and convenient operation was developed to prepare dandelion-shaped LaNiO3/NiO (CSD-LaNiO3/NiO) with core-shell structure. The as-obtained CSD-LaNiO3/NiO showed high conductivity due to the core LaNiO3, which helped to provide an efficient electron transmission path for the shell NiO, producing a strong synergistic effect. The results of electrochemical properties of CSD-LaNiO3/NiO, LaNiO3 and NiO samples revealed the superior specific capacitance of CSD-LaNiO3/NiO (326.8 F g-1) at 1 A g-1 compared to LaNiO3 (166.5 F g-1) and NiO (44.2 F g-1). The as-obtained CSD-LaNiO3/NiO material was then mixed with activated carbon and assembled into an asymmetric supercapacitor, which exhibited a wide potential window of 1.8 V, energy density of 30.4 Wh kg-1 at 1800 W kg-1, and specific capacity retention of 97.7% after 3000 cycles. In sum, the as-obtained core-shell nanostructure prepared by the proposed synthesis method is very promising for future development of high-performance supercapacitors.

9.
J Colloid Interface Sci ; 610: 601-609, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34848063

RESUMO

Perovskite transition metal oxides are promising materials for supercapacitor electrodes due to their high theoretical capacities. However, these materials still suffer from poor conductivity, low specific capacitance, and moderate cycle stability, restraining their practical applications. In this study, LaMnO3@CC-PPy materials were prepared by two-step electrodeposition based on the inspiring design of coaxial cables. To this end, electrochemically active LaMnO3 was first grown on carbon cloth (CC) with good flexibility and conductivity and then followed by further coating with polypyrrole (PPy) layer. The best PPy load was identified by adjusting the deposition time. The resulting LaMnO3@CC-PPy electrodes showed excellent specific capacitance reaching 862F g-1 at 1 A g-1 with retention rate of 75% at high current density of 10 A g-1, indicative of excellent rate performance. The cycle stability of the electrodes also improved after 3000 cycles at 10 A g-1 with a retention rate reaching 66%. To assemble asymmetric supercapacitor (ASC) devices, NiCo2O4@CC cathodes were prepared by electrodeposition. Ultra-high energy density of about 73 Wh kg-1 and good cycle stability were recorded with the devices. The high performance of the as-obtained materials was attributed to the existence of internal and external double electric channels, as well as the abundant internal space. These features ensured good conductivity, rapid charge transfer, and fast ion diffusion, thereby significantly improving the overall material cycle stability. In sum, these findings look promising for future preparation of high-performance perovskite supercapacitors.

10.
Intern Med J ; 52(8): 1374-1380, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-33665935

RESUMO

BACKGROUND: Hyperglycaemia is related to adverse outcomes in patients with acute ischaemic stroke (AIS) treated with mechanical thrombectomy (MT). AIMS: To compare the predictive ability of admission blood glucose (ABG), fasting blood glucose (FBG) and glycated haemoglobin (HbA1c) in patients with acute large vessel occlusion (ALVO) stroke undergoing MT. METHODS: The study retrospectively analysed the data of 329 consecutive acute stroke patients treated with MT. Multivariate logistic regression analysis was performed to investigate the predictors of poor functional outcome. Receiver operating characteristic (ROC) analysis was performed to identify the predictive ability of ABG, FBG and HbA1c for poor functional independence in patients with ALVO stroke undergoing MT. In addition, subgroup analyses were performed for both diabetic and non-diabetic patients. RESULTS: Multiple logistic regression analysis demonstrated that ABG and FBG were independent predictors of 3-month poor functional outcome; however, HbA1c could not predict poor functional outcome. ROC analysis showed that FBG has a higher predictive ability than ABG (areas under the ROC curve (AUC): 0.689 vs 0.624; P = 0.037) and HbA1c (AUC: 0.689 vs 0.541; P < 0.001) for poor function outcome. CONCLUSIONS: ABG and FBG are independent predictors of poor functional outcome in patients with AIS undergoing MT, and FBG has a higher predictive ability than ABG and HbA1c.


Assuntos
Isquemia Encefálica , AVC Isquêmico , Acidente Vascular Cerebral , Glicemia , Isquemia Encefálica/etiologia , Isquemia Encefálica/cirurgia , Glucose , Humanos , Estudos Retrospectivos , Acidente Vascular Cerebral/cirurgia , Trombectomia , Resultado do Tratamento
11.
J Colloid Interface Sci ; 609: 878-889, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34836655

RESUMO

Bi2O3 is an outstanding electrode material due to its high theoretical specific capacity. Hence, the synthesis of δ-Bi2O3 materials with high oxygen-vacancy contents could improve their electrochemical performances but causes easy conversion to α-Bi2O3 with low oxygen-vacancy contents, leading to poor cycling stability and limited practical applications. To overcome these problems, an effective strategy for constructing high oxygen vacancies α-Bi2O3 on activated carbon fiber paper (ACFP) is developed in this study. To this end, ACFP/Bi(OH)3 is first synthesized by the solvothermal method and then converted to ACFP/α-Bi2O3 by in situ electrochemical activation. The proposed innovative electrochemical method quickly and easily introduces oxygen vacancies while preserving the three-dimensional structure, thereby promoting the charge transfer and ions diffusion in ACFP/α-Bi2O3. Consequently, the specific capacity of ACFP/α-Bi2O3 reaches 906C g-1 at 1 A g-1, and the capacity retention remains above 70% after 3000 cycles, a value higher than that of δ-Bi2O3 (45%). Furthermore, the hybrid supercapacitor device assembled by ACFP/α-Bi2O3 delivers a maximum energy density of 114.9 Wh kg-1 at 900 W kg-1 and outstanding cycle stability with 73.56 % retention after 5500 cycles. In sum, the proposed ACFP/α-Bi2O3 with high performance and good stability looks promising for use as bismuth-based anode materials in supercapacitors and aqueous batteries.

12.
Science ; 371(6534): 1133-1138, 2021 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-33542148

RESUMO

Engineering moiré superlattices by twisting layers in van der Waals (vdW) heterostructures has uncovered a wide array of quantum phenomena. We constructed a vdW heterostructure that consists of three graphene layers stacked with alternating twist angles ±Î¸. At the average twist angle θ ~ 1.56°, a theoretically predicted "magic angle" for the formation of flat electron bands, we observed displacement field-tunable superconductivity with a maximum critical temperature of 2.1 kelvin. By tuning the doping level and displacement field, we found that superconducting regimes occur in conjunction with flavor polarization of moiré bands and are bounded by a van Hove singularity (vHS) at high displacement fields. Our findings display inconsistencies with a weak coupling description, suggesting that the observed moiré superconductivity has an unconventional nature.

13.
Nature ; 583(7815): 221-225, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32641816

RESUMO

Reducing the energy bandwidth of electrons in a lattice below the long-range Coulomb interaction energy promotes correlation effects. Moiré superlattices-which are created by stacking van der Waals heterostructures with a controlled twist angle1-3-enable the engineering of electron band structure. Exotic quantum phases can emerge in an engineered moiré flat band. The recent discovery of correlated insulator states, superconductivity and the quantum anomalous Hall effect in the flat band of magic-angle twisted bilayer graphene4-8 has sparked the exploration of correlated electron states in other moiré systems9-11. The electronic properties of van der Waals moiré superlattices can further be tuned by adjusting the interlayer coupling6 or the band structure of constituent layers9. Here, using van der Waals heterostructures of twisted double bilayer graphene (TDBG), we demonstrate a flat electron band that is tunable by perpendicular electric fields in a range of twist angles. Similarly to magic-angle twisted bilayer graphene, TDBG shows energy gaps at the half- and quarter-filled flat bands, indicating the emergence of correlated insulator states. We find that the gaps of these insulator states increase with in-plane magnetic field, suggesting a ferromagnetic order. On doping the half-filled insulator, a sudden drop in resistivity is observed with decreasing temperature. This critical behaviour is confined to a small area in the density-electric-field plane, and is attributed to a phase transition from a normal metal to a spin-polarized correlated state. The discovery of spin-polarized correlated states in electric-field-tunable TDBG provides a new route to engineering interaction-driven quantum phases.

14.
Nat Commun ; 10(1): 5333, 2019 11 25.
Artigo em Inglês | MEDLINE | ID: mdl-31767862

RESUMO

Two graphene monolayers twisted by a small magic angle exhibit nearly flat bands, leading to correlated electronic states. Here we study a related but different system with reduced symmetry - twisted double bilayer graphene (TDBG), consisting of two Bernal stacked bilayer graphenes, twisted with respect to one another. Unlike the monolayer case, we show that isolated flat bands only appear on application of a vertical displacement field. We construct a phase diagram as a function of twist angle and displacement field, incorporating interactions via a Hartree-Fock approximation. At half-filling, ferromagnetic insulators are stabilized with valley Chern number [Formula: see text]. Upon doping, ferromagnetic fluctuations are argued to lead to spin-triplet superconductivity from pairing between opposite valleys. We highlight a novel orbital effect arising from in-plane fields plays an important role in interpreting experiments. Combined with recent experimental findings, our results establish TDBG as a tunable platform to realize rare phases in conventional solids.

15.
Phys Rev Lett ; 121(19): 197002, 2018 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-30468585

RESUMO

The phenomenon of T-linear resistivity commonly observed in a number of strange metals has been widely seen as evidence for the breakdown of the quasiparticle picture of metals. This study shows that a recently discovered H/T scaling relationship in the magnetoresistance of the strange metal BaFe_{2}(As_{1-x}P_{x})_{2} is independent of the relative orientations of current and magnetic field. Rather, its magnitude and form depend only on the orientation of the magnetic field with respect to a single crystallographic axis: the direction perpendicular to the magnetic iron layers. This finding suggests that the magnetotransport scaling does not originate from the conventional averaging or orbital velocity of quasiparticles as they traverse a Fermi surface, but rather from dissipation arising from two-dimensional correlations.

16.
Sci Rep ; 7: 42436, 2017 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-28181595

RESUMO

The global change in protein abundance in colorectal cancer (CRC) and its contribution to tumorigenesis have not been comprehensively analyzed. In this study, we conducted a comprehensive proteomic analysis of paired tumors and adjacent tissues (AT) using high-resolution Fourier-transform mass spectrometry and a novel algorithm of quantitative pathway analysis. 12380 proteins were identified and 740 proteins that presented a 4-fold change were considered a CRC proteomic signature. A significant pattern of changes in protein abundance was uncovered which consisted of an imbalance in protein abundance of inhibitory and activating regulators in key signal pathways, a significant elevation of proteins in chromatin modification, gene expression and DNA replication and damage repair, and a decreased expression of proteins responsible for core extracellular matrix architectures. Specifically, based on the relative abundance, we identified a panel of 11 proteins to distinguish CRC from AT. The protein that showed the greatest degree of overexpression in CRC compared to AT was Dipeptidase 1 (DPEP1). Knockdown of DPEP1 in SW480 and HCT116 cells significantly increased cell apoptosis and attenuated cell proliferation and invasion. Together, our results show one of largest dataset in CRC proteomic research and provide a molecular link from genomic abnormalities to the tumor phenotype.


Assuntos
Neoplasias Colorretais/metabolismo , Proteoma , Proteômica , Transdução de Sinais , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Cromatina/genética , Cromatina/metabolismo , Neoplasias Colorretais/genética , Glicólise , Humanos , Proteômica/métodos
17.
Nanoscale ; 7(38): 15635-42, 2015 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-26285001

RESUMO

The retrograde neuroanatomical tracing method is a key technique to study the complex interconnections of the nervous system. Traditional tracers have several drawbacks, including time-consuming immunohistochemical or immunofluorescent staining procedures, rapid fluorescence quenching and low fluorescence intensity. Carbon dots (CDs) have been widely used as a fluorescent bio-probe due to their ultrasmall size, excellent optical properties, chemical stability, biocompatibility and low toxicity. Herein, we develop a novel fluorescent neural tracer: cholera toxin B-carbon dot conjugates (CTB-CDs). It can be taken up and retrogradely transported by neurons in the peripheral nervous system of rats. Our results show that CTB-CDs possess high photoluminescence intensity, good optical stability, a long shelf-life and non-toxicity. Tracing with CTB-CDs is a direct and more economical way of performing retrograde labelling experiments. Therefore, CTB-CDs are reliable fluorescent retrograde tracers.


Assuntos
Toxina da Cólera/química , Corantes Fluorescentes/química , Neurônios/metabolismo , Pontos Quânticos/química , Animais , Toxina da Cólera/farmacocinética , Corantes Fluorescentes/farmacocinética , Masculino , Neurônios/química , Células PC12 , Sistema Nervoso Periférico/química , Sistema Nervoso Periférico/metabolismo , Ratos , Ratos Wistar
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