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1.
Inorg Chem ; 63(16): 7430-7441, 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38605566

RESUMO

Most nonoxide catalysts based on transition metal elements will inevitably change their primitive phases under anodic oxidation conditions in alkaline media. Establishing a relationship between the bulk phase and surface evolution is imperative to reveal the intrinsic catalytic active sites. In this work, it is demonstrated that the introduction of Fe facilitates the phase transition of orthorhombic CoSe2 into its cubic counterpart and then accelerates the Co-Fe hydroxide layer generation on the surface during electrocatalytic oxygen evolution reaction (OER). As a result, the Fe-doped cubic CoSe2 catalyst exhibits a significantly enhanced activity with a considerable overpotential decrease of 79.9 and 66.9 mV to deliver 10 mA·cm-2 accompanied by a Tafel slope of 48.0 mV·dec-1 toward OER when compared to orthorhombic CoSe2 and Fe-doped orthorhombic CoSe2, respectively. Density functional theory (DFT) calculations reveal that the introduction of Fe on the surface hydroxide layers will tune electron density around Co atoms and raise the d-band center. These findings will provide deep insights into the surface reconstitution of the OER electrocatalysts based on transition metal elements.

2.
Sensors (Basel) ; 23(10)2023 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-37430840

RESUMO

When performing indoor tasks, miniature swarm robots are suffered from their small size, poor on-board computing power, and electromagnetic shielding of buildings, which means that some traditional localization methods, such as global positioning system (GPS), simultaneous localization and mapping (SLAM), and ultra-wideband (UWB), cannot be employed. In this paper, a minimalist indoor self-localization approach for swarm robots is proposed based on active optical beacons. A robotic navigator is introduced into a swarm of robots to provide locally localization services by actively projecting a customized optical beacon on the indoor ceiling, which contains the origin and the reference direction of localization coordinates. The swarm robots observe the optical beacon on the ceiling via a bottom-up-view monocular camera, and extract the beacon information on-board to localize their positions and headings. The uniqueness of this strategy is that it uses the flat, smooth, and well-reflective ceiling in the indoor environment as a ubiquitous plane for displaying the optical beacon; meanwhile, the bottom-up view of swarm robots is not easily blocked. Real robotic experiments are conducted to validate and analyze the localization performance of the proposed minimalist self-localization approach. The results show that our approach is feasible and effective, and can meet the needs of swarm robots to coordinate their motion. Specifically, for the stationary robots, the average position error and heading error are 2.41 cm and 1.44°; when the robots are moving, the average position error and heading error are less than 2.40 cm and 2.66°.

3.
Entropy (Basel) ; 25(12)2023 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-38136518

RESUMO

We applied the time-series clustering method to analyze the trajectory data of rummy-nose tetra (Hemigrammus rhodostomus), with a particular focus on their spontaneous paired turning behavior. Firstly, an automated U-turn maneuver identification method was proposed to extract turning behaviors from the open trajectory data of two fish swimming in an annular tank. We revealed two distinct ways of pairwise U-turn swimming, named dominated turn and non-dominated turn. Upon comparison, the dominated turn is smoother and more efficient, with a fixed leader-follower relationship, i.e., the leader dominates the turning process. Because these two distinct ways corresponded to different patterns of turning feature parameters over time, we incorporated the Toeplitz inverse covariance-based clustering (TICC) method to gain deeper insights into this process. Pairwise turning behavior was decomposed into some elemental state compositions. Specifically, we found that the main influencing factor for a spontaneous U-turn is collision avoidance with the wall. In dominated turn, when inter-individual distances were appropriate, fish adjusted their positions and movement directions to achieve turning. Conversely, in closely spaced non-dominated turn, various factors such as changes in distance, velocity, and movement direction resulted in more complex behaviors. The purpose of our study is to integrate common location-based analysis methods with time-series clustering methods to analyze biological behavioral data. The study provides valuable insights into the U-turn behavior, motion characteristics, and decision factors of rummy-nose tetra during pairwise swimming. Additionally, the study extends the analysis of fish interaction features through the application of time-series clustering methods, offering a fresh perspective for the analysis of biological collective data.

4.
Small ; 18(43): e2106719, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35182009

RESUMO

Recycling spent lithium-ion batteries (LIBs) is an urgent task in view of the resource shortage and environmental concerns. Here, a facile ternary molten salt approach is presented for efficiently regenerating the LiNi0.5 Co0.2 Mn0.3 O2 (NCM523) cathode of spent LIBs. Such an approach involves the treatment of spent cathode powder in the ternary molten salt at a moderate temperature (400 °C) and subsequent annealing in oxygen. The Li loss and degraded phases in spent NCM that cause the capacity decay can be fully remedied after the regeneration process. As a result, the regenerated cathode delivers a reversible capacity of 160 mAh g-1 at 0.5 C with retention of 93.7% after 100 cycles and maintains a high capacity of 132 mAh g-1 at a high rate of 5 C. The electrochemical performance of regenerated NCM cathode is compared favorably to the fresh NCM cathode, which demonstrates the feasibility of the molten salt approach to directly regenerate spent NCM cathode.

5.
J Neuroinflammation ; 18(1): 112, 2021 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-33975617

RESUMO

BACKGROUND: Accumulating evidence suggests that disease-associated microglia (DAM), a recently discovered subset of microglia, plays a protective role in neurological diseases. Targeting DAM phenotypic transformation may provide new therapeutic options. However, the relationship between DAM and epilepsy remains unknown. METHODS: Analysis of public RNA-sequencing data revealed predisposing factors (such as dipeptidyl peptidase IV; DPP4) for epilepsy related to DAM conversion. Anti-epileptic effect was assessed by electroencephalogram recordings and immunohistochemistry in a kainic acid (KA)-induced mouse model of epilepsy. The phenotype, morphology and function of microglia were assessed by qPCR, western blotting and microscopic imaging. RESULTS: Our results demonstrated that DPP4 participated in DAM conversion and epilepsy. The treatment of sitagliptin (a DPP4 inhibitor) attenuated KA-induced epilepsy and promoted the expression of DAM markers (Itgax and Axl) in both mouse epilepsy model in vivo and microglial inflammatory model in vitro. With sitagliptin treatment, microglial cells did not display an inflammatory activation state (enlarged cell bodies). Furthermore, these microglia exhibited complicated intersections, longer processes and wider coverage of parenchyma. In addition, sitagliptin reduced the activation of NF-κB signaling pathway and inhibited the expression of iNOS, IL-1ß, IL-6 and the proinflammatory DAM subset gene CD44. CONCLUSION: The present results highlight that the DPP4 inhibitor sitagliptin can attenuate epilepsy and promote DAM phenotypic transformation. These DAM exhibit unique morphological features, greater migration ability and better surveillance capability. The possible underlying mechanism is that sitagliptin can reduce the activation of NF-κB signaling pathway and suppress the inflammatory response mediated by microglia. Thus, we propose DPP4 may act as an attractive direction for DAM research and a potential therapeutic target for epilepsy.


Assuntos
Inibidores da Dipeptidil Peptidase IV/farmacologia , Dipeptidil Peptidases e Tripeptidil Peptidases/metabolismo , Epilepsia/patologia , Microglia/metabolismo , Animais , Diferenciação Celular/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microglia/efeitos dos fármacos , Fenótipo , Fosfato de Sitagliptina/farmacologia
6.
BMC Public Health ; 21(1): 615, 2021 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-33781260

RESUMO

BACKGROUND: COVID-19 is still spreading rapidly around the world. In this context, how to accurately predict the turning point, duration and final scale of the epidemic in different countries, regions or cities is key to enabling decision makers and public health departments to formulate intervention measures and deploy resources. METHODS: Based on COVID-19 surveillance data and human mobility data, this study predicts the epidemic trends of national and state regional administrative units in the United States from July 27, 2020, to January 22, 2021, by constructing a SIRD model considering the factors of "lockdown" and "riot". RESULTS: (1) The spread of the epidemic in the USA has the characteristics of geographical proximity. (2) During the lockdown period, there was a strong correlation between the number of COVID-19 infected cases and residents' activities in recreational areas such as parks. (3) The turning point (the point of time in which active infected cases peak) of the early epidemic in the USA was predicted to occur in September. (4) Among the 10 states experiencing the most severe epidemic, New York, New Jersey, Massachusetts, Texas, Illinois, Pennsylvania and California are all predicted to meet the turning point in a concentrated period from July to September, while the turning point in Georgia is forecast to occur in December. No turning points in Florida and Arizona were foreseen for the forecast period, with the number of infected cases still set to be growing rapidly. CONCLUSIONS: The model was found accurately to predict the future trend of the epidemic and can be applied to other countries. It is worth noting that in the early stage there is no vaccine or approved pharmaceutical intervention for this disease, making the fight against the pandemic reliant on non-pharmaceutical interventions. Therefore, reducing mobility, focusing on personal protection and increasing social distance remain still the most effective measures to date.


Assuntos
COVID-19/epidemiologia , COVID-19/transmissão , Migração Humana/estatística & dados numéricos , Pandemias/prevenção & controle , COVID-19/prevenção & controle , Controle de Doenças Transmissíveis , Humanos , Modelos Teóricos , SARS-CoV-2 , Estados Unidos/epidemiologia
7.
Chemistry ; 20(24): 7419-28, 2014 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-24806996

RESUMO

The radical copolymerization of cyclic ester ß-propiolactone (ß-PL) with styrene (St) at 120 °C, with a complete range of monomer ratios, is a rare example of a system providing graft copolymers (PSt-g-ß-PL) in one pot. The structure of the resulting ß-PL-St copolymers was proven by using a combination of different characterization techniques, such as 1D and 2D NMR spectroscopy and gel permeation chromatography (GPC), before and after alkaline hydrolysis of the polymers. The number of grafting points increased with an increasing amount of ß-PL in the feed. A significant difference in the reactivity of St and ß-PL and radical chain-transfer reactions at the polystyrene (PSt) backbone, followed by combination with the active growing poly(ß-PL) chains, led to the formation of graft copolymers by a grafting-onto mechanism.


Assuntos
Poliésteres/química , Polímeros/química , Espectroscopia de Ressonância Magnética , Polimerização
8.
Macromol Rapid Commun ; 35(2): 234-241, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24115272

RESUMO

The synthesis of well-defined cylindrical polymer brushes (CPBs) from a linear polymer backbone with a high density of RAFT functionalities ("grafting from" approach) is challenging when the chain transfer agent (CTA) is attached to the backbone via its R-group. It is proposed that the difficulties of the R-group approach in controlling the grafting polymerization are induced by the "entrapment" of active free radicals within individual growing CPBs. A facile "CTA-shuttled" R-group approach overcoming this entrapment effect is developed, and used to synthesize well-defined CPBs with polystyrene or poly(tert-butyl acrylate) branches and core-shell CPBs with polystyrene-block-poly(N-isopropylacrylamide) branches. The polydispersity index (PDI = 1.23) of the obtained CPBs with polystyrene branches is much lower than that from the conventional R-group approach (PDI = 2.18). Monte Carlo simulations confirm that the advantage of the "CTA-shuttled" R-group approach consists in the release of the active radicals from the trapping CPB systems.


Assuntos
Polímeros/química , Polimerização
9.
Macromol Rapid Commun ; 35(1): 52-5, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24327396

RESUMO

Imitating the natural "energy cascade" architecture, we present a single-molecular rod-like nano-light harvester (NLH) based on a cylindrical polymer brush. Block copolymer side chains carrying (9,9-diethylfluoren-2-yl)methyl methacrylate units as light absorbing antennae (energy donors) are tethered to a linear polymer backbone containing 9-anthracenemethyl methacrylate units as emitting groups (energy acceptors). These NLHs exhibit very efficient energy absorption and transfer. Moreover, we manipulate the energy transfer by tuning the donor-acceptor distance.


Assuntos
Luz , Nanotecnologia , Transferência de Energia , Polímeros/química , Análise Espectral/métodos
10.
Chem Sci ; 15(26): 10172-10181, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38966372

RESUMO

Metal-support interaction engineering is considered an efficient strategy for optimizing the catalytic activity. Nevertheless, the fine regulation of metal-support interactions as well as understanding the corresponding catalytic mechanisms (particularly those of non-carbon support-based counterparts) remains challenging. Herein, a controllable adsorption-impregnation strategy was proposed for the preparation of a porous nonlayered 2D NiO nanoflake support anchored with different forms of Pt nanoarchitectures, i.e. single atoms, clusters and nanoparticles. Benefiting from the unique porous architecture of NiO nanosheets, abundant active defect sites facilitated the immobilization of Pt single atoms onto the NiO crystal, resulting in NiO lattice distortion and thus changing the valence state of Pt, chemical bonding, and the coordination environment of the metal center. The synergy of the porous NiO support and the unexpected Pt single atom-NiO interactions effectively accelerated mass transfer and reduced the reaction kinetic barriers, contributing to a significantly enhanced mass activity of 5.59 A mgPt -1 at an overpotential of 0.274 V toward the electrocatalytic oxygen evolution reaction (OER) while 0.42 A mgPt -1 at a potential of 0.7 V vs. RHE for the methanol oxidation reaction (MOR) in an alkaline system, respectively. This work may offer fundamental guidance for developing metal-loaded/dispersed support nanomaterials toward electrocatalysis through the fine regulation of metal-support interactions.

11.
Nat Commun ; 15(1): 4779, 2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38839782

RESUMO

Despite the profound implications of self-organization in animal groups for collective behaviors, understanding the fundamental principles and applying them to swarm robotics remains incomplete. Here we propose a heuristic measure of perception of motion salience (MS) to quantify relative motion changes of neighbors from first-person view. Leveraging three large bird-flocking datasets, we explore how this perception of MS relates to the structure of leader-follower (LF) relations, and further perform an individual-level correlation analysis between past perception of MS and future change rate of velocity consensus. We observe prevalence of the positive correlations in real flocks, which demonstrates that individuals will accelerate the convergence of velocity with neighbors who have higher MS. This empirical finding motivates us to introduce the concept of adaptive MS-based (AMS) interaction in swarm model. Finally, we implement AMS in a swarm of ~102 miniature robots. Swarm experiments show the significant advantage of AMS in enhancing self-organization of the swarm for smooth evacuations from confined environments.


Assuntos
Aves , Robótica , Animais , Aves/fisiologia , Percepção de Movimento/fisiologia , Comportamento Animal/fisiologia , Movimento (Física) , Voo Animal/fisiologia , Comportamento Social
12.
Sci Total Environ ; 856(Pt 2): 159075, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36174685

RESUMO

Recently, drought events have occurred frequently and have profoundly altered the carbon sequestration in terrestrial ecosystems. How drought affects carbon sequestration is an important issue which may assist in understanding and confronting the challenges of extreme climate change. Nevertheless, drought-induced carbon-cycle effects remain scarce from the perspective of drought indices. In this study, we quantified the impacts of potential evapotranspiration (PET), standardized precipitation evapotranspiration index (SPEI), downward short-wave radiation flux (SWDown), and soil water (Soil_w) on net ecosystem productivity (NEP). We showed that the spatiotemporal heterogeneity of drought was extremely significant, and the hot spots of aridification were mainly distributed in the southwestern Yungui Plateau (YG) and Northwest China (NW). Moreover, the "pan evaporation paradox" appeared across the Chinese mainland before the 1990s and subsequently disappeared. Similarly, in contrast to the moderate NEP fluctuation between 1981 and 1999, since the beginning of the 21st century, NEP has increased significantly across Chinese mainland, YG, the plains region of Changjiang (CJ), and Southeast China (SE). Meanwhile, there are obvious directional, temporal, and spatial differences in the effects of the drought indices on NEP. Specifically, a higher SPEI value results in a more obvious promoting effect on NEP in SE, North China (NN), and northeastern YG. An increase in SWDown can promote an increase in NEP, especially in the northeastern YG and central SE. The increase in Soil_w in parts of the Qinghai-Tibetan Plateau, Xinjiang Region (XJ), southeastern NW, NN, and Northeast China with poor water conditions can promote carbon sinks. The inhibition effect is particularly obvious in some areas of CJ, where water resources are abundant. The fluctuation in PET has a relatively low influence on NEP. This study provides a comprehensive assessment of drought change and its impact on carbon sequestration and may help in formulating appropriate policies for carbon management and ecological security.


Assuntos
Sequestro de Carbono , Secas , Ecossistema , Mudança Climática , Solo , Carbono/análise , Água , China
13.
Artigo em Inglês | MEDLINE | ID: mdl-36762457

RESUMO

Li metal is the ultimate anode material for next-generation high-energy-density rechargeable batteries. However, the uncontrollable growth of Li dendrites and low Coulombic efficiency (CE) prevent it from practical applications in Li metal batteries (LMBs). Here, a facile and low-cost strategy is developed to decorate a Cu current collector with a self-assembled γ-aminopropyltrimethoxysilane (γ-APS) film. The thin polymer film with nanopores promotes the formation of cobblestone-like Li deposition and suppresses Li-dendrite formation due to its low surface energy. The protecting layer not only increases the lithiophilicity of the Cu current collector but also alleviates the ambient corrosion and galvanic corrosion in practical use. Owing to these advantages, the half cell using γ-APS-Cu collectors exhibits a high average CE value of 99.2% for 100 cycles. The symmetric cell of γ-APS-Cu@Li shows an improved lifespan of 1400 h with a small voltage hysteresis of 12 mV at 0.5 mA cm-2. The full cell assembled with LiFePO4 (LFP) cathodes and γ-APS-Cu@Li anodes delivers a high capacity of 136 mAh g-1 after 600 cycles at 0.5C.

14.
ACS Appl Mater Interfaces ; 15(29): 34852-34861, 2023 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-37459587

RESUMO

The high specific capacity and relatively low volume expansion of silicon suboxide (SiOx) highlight its potential as one of the most promising anode materials for lithium-ion batteries. Nevertheless, the traditional binder of polyacrylic acid (PAA) still cannot adapt to enormous stress during the repeated volume expansion/contraction owing to its intrinsic rigid backbone. Inspired by the "soft and hard composite body armor", we herein design a double-wrapped binder consisting of PAA with a high internal Young's modulus (hard part) and polyurethane (DOU) with a low external Young's modulus (soft part). When the SiOx particle expands during lithiation, the rigid PAA firstly accommodates the volume change to dissipate most of the inner stress, and the elastic DOU with triple dynamic bonds serves as a buffer layer to absorb the residual stress via the breakage/formation of dynamic bonds. By optimizing the PAA/DOU ratio, the SiOx anode can maintain the integrity during long-term cycling and deliver a relatively high reversible capacity of 1064.1 mAh g-1 with a preeminent capacity retention of 83.7% at 0.5C after 300 cycles. Such a double-wrapped binder can provide a novel design strategy for multicomponent functional polymer binders toward high-performance SiOx anodes.

15.
Sci Total Environ ; 884: 163791, 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37142033

RESUMO

Global climate change and revegetation programs have significantly changed the ecological quality (EQ) in the Chinese mainland after 1999. Monitoring and assessing the changes in the regional EQ and analyzing their drivers are crucial for ensuring ecological restoration and rehabilitation. However, it is challenging to carry out a long-term and large-scale quantitative assessment of the EQ of a region based on traditional field investigations and experiment methods alone; notably, in previous studies, the effects of carbon and water cycles and human activities on the variations in EQ have not been studied comprehensively. Therefore, in addition to remote sensing data and principal component analysis, we used the remote sensing-based ecological index (RSEI), to assess the EQ changes in the Chinese mainland during 2000-2021. Additionally, we also analyzed the impacts of carbon and water cycles and anthropological activities on the changes in the RSEI. The main conclusions of this study were: since the beginning of the 21st century, we observed a fluctuating upward trend in the EQ changes in the Chinese mainland and eight climatic regions. From 2000 to 2021, in terms of the EQ, North China (NN) portrayed the highest increase rate (2.02 × 10-3 year-1, P < 0.05). There was a breaking point in 2011, the EQ in the region experienced a change, from a downward trend to an upward one. Northwest China, Northeast China, and NN portrayed an overall significant increasing trend in the RSEI, whereas the southwest part of the Southwest Yungui Plateau (YG) and a part of the plain region of the Changjiang (Yangtze) River (CJ) river region portrayed a significant decreasing trend in the EQ. Overall, the carbon and water cycles and human activities played a pivotal role in determining the spatial patterns and trends of the EQ in the Chinese mainland. In particular, the self-calibrating Palmer Drought Severity Index, actual evapotranspiration (AET), gross primary productivity (GPP), and soil water content (Soil_w) were identified as the key drivers of the RSEI. In the central and western Qinghai-Tibetan Plateau (QZ) and the northwest region of NW, the changes in RSEI were dominated by AET; however, in central NN, southeastern QZ, northern YG, and central NE, the changes were driven by GPP, and in the southeast region of NW, south region of NE, northern region of NN, middle YG region, and a part of the middle CJ region, the changes were driven by Soil_w. The population-density-related change in the RSEI was positive in the northern regions (NN and NW) but negative in the southern regions (SE), whereas the RSEI change related to ecosystem services was positive in the NE, NW, QZ, and YG regions. These results are beneficial for the adaptive management and protection of the environment and the realization of green and sustainable developmental strategies in the Chinese mainland.


Assuntos
Ecossistema , Meio Ambiente , Humanos , Carbono , China , Tecnologia de Sensoriamento Remoto , Solo , Ciclo Hidrológico , Ciclo do Carbono , Efeitos Antropogênicos
16.
Sci Rep ; 12(1): 8601, 2022 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-35597774

RESUMO

Plenty of empirical evidence on biological swarms reveal that interaction between individuals is selective. Each individual's neighbor is selected based on one or more featured factors. Based on the self-propelled model, we develop a general probability neighbor selection framework to study the effect of four typical featured factors (i.e., distance, bearing, orientation change and bearing change). In this work, two common cases are involved to comprehensively analyze the impact of the four featured factors on the collective motion. One is the flocking, the other is the responsivity to stimulus. The impact of different selection strengths of the featured factors on both cases are investigated. The effect of noise on flocking and different stimulus intensities on responsivity to stimulus are analyzed. This study allows us to get the insight of selective interaction and suggests the potential solution to overcome the trade-off between flocking and responsivity quality.


Assuntos
Ruído , Humanos , Movimento (Física)
17.
Environ Sci Pollut Res Int ; 29(44): 66191-66203, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35499729

RESUMO

The geometric structure of the suspended carrier is an important factor that directly affects the effluent quality of the moving bed biofilm reactor, and it should be a valuable mathematical solution to solve the nonlinear equation through numerical simulation and experimental research. Therefore, this study has designed and prepared a coral-shaped fractal suspension carrier based on nonlinear equations and verified the effectiveness of the new carrier for sewage treatment through FLUENT numerical simulation and domestic sewage treatment experiments. The experimental results show that the coral-shaped fractal suspension carrier has a significant effect on the velocity, vortex distribution, and gas-phase distribution of the flow field in the reactor. The mass transfer dead area in the reactor is reduced, the number of vortices is significantly increased, and the fractal dimension of the carrier is negatively correlated with the flow velocity and pressure drop of the fluid. After stabilization, the average removal rates of COD and NH4+-N by the reactor are 89.5% and 93.21%, respectively; the effluent quality reaches the national first-class A standard; and the sewage treatment performance is good. At the same time, this research provides a preliminary research basis for the method of solving nonlinear equations through numerical simulation and experimental research.


Assuntos
Esgotos , Eliminação de Resíduos Líquidos , Biofilmes , Reatores Biológicos , Desnitrificação , Fractais , Nitrogênio/análise , Esgotos/química , Eliminação de Resíduos Líquidos/métodos
18.
Dalton Trans ; 51(29): 11098-11107, 2022 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-35796250

RESUMO

Electrocatalytic overall water splitting is a sustainable approach to realizing the clean production of hydrogen energy; however, it is mainly hindered by the sluggish kinetics of the oxygen evolution reaction (OER). For large-scale hydrogen production, it is great urgent to develop efficient and low-cost OER electrocatalyst candidates from commercial noble metal-based materials. Herein, a facile template method was proposed for the preparation of a series of hierarchical NiFeV hydroxide nanotubes. With the combined advantages of a hierarchical nanostructure and the synergistic effect among multi-metal elements, the ternary hydroxides delivered outstanding OER performance. In particular, a low overpotential of 256.5 mV delivering a current density of 10 mA cm-2 with a Tafel slope of 52.4 mV dec-1 was achieved by hierarchical NiFeV hydroxide nanotubes with an initial Ni/Fe/V feed ratio of 8 : 1 : 1. After a subsequent topotactic transformation, ternary phosphide (denoted as NiFeVP) was obtained with the hierarchical nanostructure well maintained, and it achieved further performance enhancement where an overpotential of only 209.5 mV was required to deliver 10 mA cm-2 with a lower Tafel slope of 30.3 mV dec-1 and excellent durability for 50 h for chronopotentiometry even at 50 mA cm-2, demonstrating an admirable OER electrocatalyst.

19.
Small Methods ; 6(12): e2201299, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36333213

RESUMO

Poor intrinsic conductivity and the presence of irreversible lithiation phase affect the electrochemical performance of silicon oxycarbide anode materials. Even though it can be improved by increasing free carbon content or composition, scarification of reversible capacity and initial Coulombic efficiency (ICE) remain as challenge. Here, polycarbosilane (PCS) with alternating distribution of silicon and carbon atoms is employed as precursor of SiOC ceramics. Air oxidation cross-linking is used to regulate the content of oxygen and carbon elements in PCS at atom level, so as to explore a solution to improve the intrinsic conductivity and reversible lithium phase content of SiOC ceramics. This strategy provides extremely excellent rate capability, areal/volumetric capacity, and ICE. This is also the first concept for feasible precursor structure design to control the SiOC glass phase and regulate the growth of C nanoribbon that can improve the intrinsic conductivity and reversible capacity of SiOC ceramic anode materials.

20.
Int J Biol Macromol ; 212: 257-274, 2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35533849

RESUMO

The aim of this study was to investigate the effect of a polysaccharide from Rosa rugosa Thunb. on human cervical cancer cells (HCCCs) and the underlying mechanism. Here, a novel Rosa rugosa polysaccharide, named as RRP, was purified from Rosa rugosa petals. RRP consisted of glucose, galacturonic acid, mannose, rhamnose, galactose, arabinose, xylose, and glucuronic acid (molar ratio: 7.78:7.59:4.23:3.22:3.15:1.65:1.00), with Mw of 327.92 kDa. RRP remarkably inhibited cell proliferation, migration, and cell cycle arrest in HeLa and SiHa cells. Furthermore, RRP induced apoptosis by activating the caspase family of proteins and mediating the reactive oxygen species (ROS)-mediated mitochondrial pathway. In addition, RRP was found to dose-dependently induce autophagy, which occurred prior to apoptosis. RRP also primarily induced autophagy-mediated apoptosis in HCCCs via the PI3K/AKT/mTOR pathway. Thus, RRP might serve as a legitimate therapeutic drug candidates against human cervical cancer.


Assuntos
Fosfatidilinositol 3-Quinases , Proteínas Proto-Oncogênicas c-akt , Rosa , Serina-Treonina Quinases TOR , Neoplasias do Colo do Útero , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Feminino , Humanos , Fosfatidilinositol 3-Quinases/metabolismo , Polissacarídeos/farmacologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Rosa/química , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo , Neoplasias do Colo do Útero/tratamento farmacológico , Neoplasias do Colo do Útero/metabolismo , Neoplasias do Colo do Útero/patologia
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