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1.
Angew Chem Int Ed Engl ; 62(50): e202311968, 2023 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-37885357

RESUMO

The large-scale deployment of CO2 electroreduction is hampered by deficient carbon utilization in neutral and alkaline electrolytes due to CO2 loss into (bi)carbonates. Switching to acidic media mitigates carbonation, but suffers from low product selectivity because of hydrogen evolution. Here we report a crown ether decoration strategy on a Cu catalyst to enhance carbon utilization and selectivity of CO2 methanation under acidic conditions. Macrocyclic 18-Crown-6 is found to enrich potassium cations near the Cu electrode surface, simultaneously enhancing the interfacial electric field to stabilize the *CO intermediate and accelerate water dissociation to boost *CO protonation. Remarkably, the mixture of 18-Crown-6 and Cu nanoparticles affords a CH4 Faradaic efficiency of 51.2 % and a single pass carbon efficiency of 43.0 % toward CO2 electroreduction in electrolyte with pH=2. This study provides a facile strategy to promote CH4 selectivity and carbon utilization by modifying Cu catalysts with supramolecules.

2.
Small ; 17(34): e2101080, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34263546

RESUMO

Transition metal oxides (TMOs) are promising anode materials for next-generation lithium-ion batteries (LIBs). Nevertheless, their poor electronic and ionic conductivity as well as huge volume change leads to low capacity release and rapid capacity decay. Herein, a reduced graphene oxide (rGO)-encapsulated TMOs strategy is developed to address the above problems. The Co3 O4 -CoFe2 O4 @rGO composites with rGO sheets-encapsulated Co3 O4 -CoFe2 O4 microcubes are successfully constructed through a simple metal-organic frameworks precursor route, in which Co[Fe(CN)5 NO] microcubes are in situ coated by graphene oxide sheets, followed by a two-step calcination process. As anode material of LIBs, Co3 O4 -CoFe2 O4 @rGO exhibits remarkable reversible capacity (1393 mAh g-1 at 0.2 A g-1 after 300 cycles), outstanding long-term cycling stability (701 mAh g-1 at 2.0 A g-1 after 500 cycles), and excellent rate capability (420 mAh g-1 at 4.0 A g-1 ). The superior lithium storage performance can be attributed to the unique double-buffer structure, in which the outer flexible rGO shells can prevent the structure collapse of the electrode and improve its conductivity, while the hierarchical porous cores of Co3 O4 -CoFe2 O4 microcubes can buffer the volume expansion. This work provides a general and straightforward strategy for the construction of novel rGO-encapsulated bimetal oxides for energy storage and conversion application.

3.
Small ; 16(21): e1907643, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32187839

RESUMO

The safety of metal oxide (MOx) nanoparticles (NPs) has been highly concerned because of their wide application and potential toxicological injury. The safe-by-design strategy is usually developed to make safer MOx NPs based on regulation of their physicochemical properties. In the present study, manganese oxide (Mn3 O4 ) NPs, as a representative of insoluble toxic MOx NPs, are doped with a series of transition metal to regulate their conduction band energy (Ec ) out of biological redox potential range (BRPR) or Fermi energy (Ef ) far away from valence band energy (Ev ), aiming at completely eliminating the toxicity or significantly reducing the toxicity. It is found that all these M-doping cannot move Ec of Mn3 O4 NPs out of the BRPR but zinc (Zn)-, copper (Cu)-, and chromium (Cr)-doping do move Ef far away from Ev , where Zn-doping results in the largest |Ef - Ev | value. Various abiotic, in vitro and in vivo assessments reveal that Zn-, Cu-, and Cr-doped Mn3 O4 NPs can generate lower amount of •OH and trigger weaker injury than Mn3 O4 NPs, where Zn-doped Mn3 O4 NPs show the lowest toxicity. Regulating Ef far away from Ev becomes a feasible safe-by-design approach to achieve safe MOx NPs.

4.
Nano Lett ; 19(10): 6800-6811, 2019 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-31466437

RESUMO

Nitric oxide (NO) molecular messenger can reverse the multidrug resistance (MDR) effect of cancer cells through reducing P-glycoprotein (P-gp) expression, beneficial for creating a favorable microenvironment for the treatment of doxorubicin (Dox)-resistant cancer cells. Development of sophisticated nanosystems to programmably release NO and Dox becomes an efficient strategy to overcome the MDR obstacles and achieve promising therapeutic effects in Dox-resistant cancer. Herein, a NO stimulated nanosystem was designed to engineer a significant time gap between NO and Dox release, promoting MDR cancer therapy. A o-phenylenediamine-containing lipid that can hydrolyze in response to NO was embedded in the phospholipid bilayer structure of liposome to form NO-responsive liposome, which could further encapsulate l-arginine (l-Arg)/Dox-loaded gold@copper sulfide yolk-shell nanoparticls (ADAu@CuS YSNPs) to form ADLAu@CuS YSNPs. Under 808 nm laser irradiation, the unique resonant energy transfer (RET) process and reactive oxygen species (ROS) generation in the confined space of ADLAu@CuS YSNPs could effectively convert l-Arg into NO, regionally destabilizing the phospholipid bilayer structure, as a result of NO release. However, at this early stage Dox could not be released from YSNPs due to the molecular scaffold limit. As the NO release progressed, the NO-responsive liposome layer was deteriorated more severely, allowing Dox to escape. This NO and Dox sequential release of ADLAu@CuS YSNPs could significantly inhibit P-gp expression and enhance Dox accumulation in Dox-resistant MCF-7/ADR cells, leading to promising in vitro and in vivo therapeutic effects and presenting their great potential for MDR cancer therapy.


Assuntos
Antineoplásicos/administração & dosagem , Neoplasias da Mama/tratamento farmacológico , Preparações de Ação Retardada/metabolismo , Doxorrubicina/administração & dosagem , Óxido Nítrico/metabolismo , Antineoplásicos/farmacocinética , Antineoplásicos/farmacologia , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Doxorrubicina/farmacocinética , Doxorrubicina/farmacologia , Liberação Controlada de Fármacos , Resistência a Múltiplos Medicamentos , Resistencia a Medicamentos Antineoplásicos , Feminino , Humanos , Lipossomos/metabolismo , Células MCF-7 , Nanopartículas/metabolismo
5.
Small ; 15(9): e1804545, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30680948

RESUMO

Developing cheap, abundant, and easily available electrocatalysts to drive the hydrogen evolution reaction (HER) at small overpotentials is an urgent demand of hydrogen production from water splitting. Molybdenum disulfide (MoS2 ) based composites have emerged as competitive electrocatalysts for HER in recent years. Herein, nickel@nitrogen-doped carbon@MoS2 nanosheets (Ni@NC@MoS2 ) hybrid sub-microspheres are presented as HER catalyst. MoS2 nanosheets with expanded interlayer spacings are vertically grown on nickel@nitrogen-doped carbon (Ni@NC) substrate to form Ni@NC@MoS2 hierarchical sub-microspheres by a simple hydrothermal process. The formed Ni@NC@MoS2 composites display excellent electrocatalytic activity for HER with an onset overpotential of 18 mV, a low overpotential of 82 mV at 10 mA cm-2 , a small Tafel slope of 47.5 mV dec-1 , and high durability in 0.5 H2 SO4 solution. The outstanding HER performance of the Ni@NC@MoS2 catalyst can be ascribed to the synergistic effect of dense catalytic sites on MoS2 nanosheets with exposed edges and expanded interlayer spacings, and the rapid electron transfer from Ni@NC substrate to MoS2 nanosheets. The excellent Ni@NC@MoS2 electrocatalyst promises potential application in practical hydrogen production, and the strategy reported here can also be extended to grow MoS2 on other nitrogen-doped carbon encapsulated metal species for various applications.

6.
Talanta ; 269: 125484, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38043338

RESUMO

Ethylene is a hormone for fruit ripening control, and for the purpose of maintaining plant quality, ethylene monitoring is crucial. Due to the simple structure and limited functionality, the technical realization of ethylene detection by an artificial sensor remains a challenge. In this paper, we present a metal-organic frameworks (MOFs) array based electronic nose (e-nose) for rapid and accurate determination of ethylene. Six zirconium-based MOFs with systematically modified pore sizes and π-π binding sites have been prepared and fabricated into a sensor array using quartz crystal microbalance (QCM) technology. By virtue of the synergistic features of six MOF sensors, selectivity detection of ethylene has been achieved. The detection limit reaches to 0.27 ± 0.02 ppm, and high selectivity and stability (98.29 % ± 0.88 %) could also be confirmed. By submitting data to machine learning algorithm, an e-nose system could be established for discriminating ethylene from mixtures with a qualitative accuracy of 90.30 % and quantitative accuracy of 98.89 %. Practical evaluation suggests that the e-nose could index the fruit quality based on the accurate detection of ethylene released during fruit ripeness. This work demonstrates the promising potential of fabricating MOFs based e-nose systems for practical monitoring applications by selectively detecting challengeable target molecules.

7.
Colloids Surf B Biointerfaces ; 240: 113998, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38823340

RESUMO

Photoactivated therapy has gradually emerged as a promising and rapid method for combating bacteria, aimed at overcoming the emergence of drug-resistant strains resulting from the inappropriate use of antibiotics and the subsequent health risks. In this work, we report the facile fabrication of Zn3[Fe(CN)6]/g-C3N4 nanocomposites (denoted as ZHF/g-C3N4) through the in-situ loading of zinc hexacyanoferrate nanospheres onto two-dimensional g-C3N4 sheets using a simple metal-organic frameworks construction method. The ZHF/g-C3N4 nanocomposite exhibits enhanced antibacterial activity through the synergistic combination of the excellent photothermal properties of ZHF and the photodynamic capabilities of g-C3N4. Under dual-light irradiation (420 nm + 808 nm NIR), the nanocomposites achieve remarkable bactericidal efficacy, eliminating 99.98% of Escherichia coli and 99.87% of Staphylococcus aureus within 10 minutes. Furthermore, in vivo animal experiments have demonstrated the outstanding capacity of the composite in promoting infected wound healing, achieving a remarkable wound closure rate of 99.22% after a 10-day treatment period. This study emphasizes the potential of the ZHF/g-C3N4 nanocomposite in effective antimicrobial applications, expanding the scope of synergistic photothermal/photodynamic therapy strategies.


Assuntos
Antibacterianos , Escherichia coli , Nanocompostos , Staphylococcus aureus , Cicatrização , Nanocompostos/química , Cicatrização/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Antibacterianos/farmacologia , Antibacterianos/química , Animais , Fotoquimioterapia , Testes de Sensibilidade Microbiana , Camundongos , Esterilização/métodos , Ferrocianetos/química , Ferrocianetos/farmacologia , Tamanho da Partícula , Zinco/química , Zinco/farmacologia , Terapia Fototérmica , Propriedades de Superfície , Compostos de Nitrogênio/química , Compostos de Nitrogênio/farmacologia , Grafite
8.
J Colloid Interface Sci ; 652(Pt B): 1793-1802, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37683407

RESUMO

Planar wearable supercapacitors (PWSCs) have sparked intense interest owing to their hopeful application in smart electronics. However, current PWSCs suffered from poor electrochemical property, weak flexibility and/or large weight. To relieve these defects, in this study, we fabricated a high-performance PWSC using silk protein derived film electrodes (PPy/RSF/MWCNTs-2; RSF, PPy and MWCNTs represent regenerated silk film, polypyrrole and multi-walled carbon nanotubes, respectively, while 2 is the mass ratio of silk to MWCNTs), which were developed by 'dissolving-mixing-evaporating' and in situ polymerization. In three-electrode, PPy/RSF/MWCNTs-2 showed a superb area specific capacitance of 8704.7 mF cm-2 at 5 mA cm-2, which surpassed numerous reported PWSC electrodes, and had a decent durability with a capacitance retention of 90.7 % after 5000 cycles. The PPy/RSF/MWCNTs-2 derived PWSC showed a largest energy density of 281.3 µWh cm-2 at 1660.1 µW cm-2, and a power density as high as 13636.4 µW cm-2 at 125.6 µWh cm-2. Furthermore, impressive capacitive-mechanical stability with a capacitance retention of 92 % under bending angles from 0 to 150 was depicted. Thanks to the rational and affordable preparation, our study for the first time prepared RSF electrode that had great capacitive property, high mechanical flexibility and light weight, simultaneously. The encouraging results can not only open up a new path to manufacture high-performance flexible electrodes, but may also help to realize the high-value-added utilization of silk.


Assuntos
Nanotubos de Carbono , Dispositivos Eletrônicos Vestíveis , Seda , Polímeros , Pirróis , Eletrodos
9.
Adv Mater ; 35(26): e2301127, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37119501

RESUMO

The electrochemical reduction of carbon dioxide into multi-carbon products (C2+ ) using renewably generated electricity provides a promising pathway for energy and environmental sustainability. Various oxide-derived copper (OD-Cu) catalysts have been showcased, but still require high overpotential to drive C2+ production owing to sluggish carbon-carbon bond formation and low CO intermediate (*CO) coverage. Here, the dilemma is circumvented by elaborately devising the OD-Cu morphology. First, computational studies propose a hollow and hierarchical OD-Cu microstructure that can generate a core-shell microenvironment to inhibit CO evolution and accelerate *CO dimerization via intermediate confinement and electric field enhancement, thereby boosting C2+ generation. Experimentally, the designed nanoarchitectures are synthesized through a heteroseed-induced approach followed by electrochemical activation. In situ spectroscopic studies further elaborate correlation between *CO dimerization and designed architectures. Remarkably, the hierarchical OD-Cu manifests morphology-dependent selectivity of CO2 reduction, giving a C2+ Faradaic efficiency of 75.6% at a considerably positive potential of -0.55 V versus reversible hydrogen electrode.

10.
Cryobiology ; 65(1): 68-71, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22561141

RESUMO

The purpose of this study was to compare a dual-freeze protocol with a triple-freeze protocol for hepatic cryoablation in a porcine model. Eighteen cryoablations were performed over an exposed operation field in nine normal porcine livers, using dual- (10-5-10-5) and triple-freeze (5-5-5-5-10-5) protocols. Changes in the temperature of the cryoprobes and the diameter of the iceballs were recorded during the ablation, and pathological changes in the cryozones (zones of tissue destruction) were assessed seven days after the procedure. Use of two and three freeze-thaw cycles produced iceballs of different diameters. Seven days after cryosurgery, the triple-freeze protocol was associated with a larger zone of complete necrosis than the dual-freeze protocol, although the two protocols produced cryozones and cryolesions of similar length, and in both cases the cryozones contained five areas of destruction. With the same freezing time (20 min), the triple-freeze protocol may be a more powerful liver ablation method than the dual-freeze protocol.


Assuntos
Criocirurgia/métodos , Fígado/cirurgia , Animais , Apoptose/fisiologia , Congelamento , Tecido de Granulação/patologia , Hiperemia/patologia , Gelo , Inflamação/patologia , Fígado/patologia , Modelos Animais , Necrose , Suínos , Porco Miniatura
11.
Cryobiology ; 64(3): 245-9, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22366171

RESUMO

The purpose of this study was to compare a dual-freeze protocol with a triple-freeze protocol for pulmonary cryoablation in a porcine lung model. Five dual- (10-5-10-5) and five triple-freeze (5-5-5-5-10-5) cryoablations were performed on an exposed operation field in normal porcine lung. Changes in the temperature of the cryoprobes and the diameter of the iceballs were measured during the ablation and pathologic changes in the cryozones (zones of tissue destruction) were reviewed 7 days after the procedure. The diameter of the iceball surface differed between the two protocols. Pathologically, the triple-freeze protocol was associated with a longer complete necrosis zone than the dual-freeze protocol, though the two protocols produced cryolesions and cryozones of similar length, and in both cases there were five areas of tissue destruction. With the same duration of freezing (20 min), the triple-freeze protocol may be better for pulmonary cryoablation than the dual-freeze protocol.


Assuntos
Criocirurgia/métodos , Pulmão/cirurgia , Animais , Congelamento , Gelo , Modelos Animais , Necrose/patologia , Suínos
12.
Biology (Basel) ; 11(11)2022 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-36358329

RESUMO

Climate change affects ecosystems and human health in multiple dimensions. With the acceleration of climate change, climate-sensitive vector-borne diseases (VBDs) pose an increasing threat to public health. This paper summaries 10 publications on the impacts of climate change on ecosystems and human health; then it synthesizes the other existing literature to more broadly explain how climate change drives the transmission and spread of VBDs through an ecological perspective. We highlight the multi-dimensional nature of climate change, its interaction with other factors, and the impact of the COVID-19 pandemic on transmission and spread of VBDs, specifically including: (1) the generally nonlinear relationship of local climate (temperature, precipitation and wind) and VBD transmission, with temperature especially exhibiting an n-shape relation; (2) the time-lagged effect of regional climate phenomena (the El Niño-Southern Oscillation and North Atlantic Oscillation) on VBD transmission; (3) the u-shaped effect of extreme climate (heat waves, cold waves, floods, and droughts) on VBD spread; (4) how interactions between non-climatic (land use and human mobility) and climatic factors increase VBD transmission and spread; and (5) that the impact of the COVID-19 pandemic on climate change is debatable, and its impact on VBDs remains uncertain. By exploring the influence of climate change and non-climatic factors on VBD transmission and spread, this paper provides scientific understanding and guidance for their effective prevention and control.

13.
J Colloid Interface Sci ; 609: 503-512, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34809991

RESUMO

The exploitation of hybrid supercapacitors with excellent electrochemical properties is of great significance for energy storage systems. Herein, a three-dimensional hierarchical flower-like architecture of nickel phosphide (Ni2P) decorated with nitrogen-doped carbon quantum dots (N-CQDs) and cobalt oxide (Co3O4) is constructed by an effective two-step hydrothermal strategy followed by in situ phosphorization process. Introducing N-CQDs with superior electrochemical characteristics can not only induce the formation of N-CQDs deposited nickel hydroxide (Ni(OH)2) flower-like architecture but also significantly enhance the electrochemical features of Ni(OH)2 nanosheets. After combination with Co3O4 nanoparticles and phosphorization treatment, an advanced cathode of Ni2P/Co3O4/N-CQDs with enriched surface phosphate ions is obtained, which possesses an ultra-high capacity of 1044 C g-1 (2088 F g-1) at 1 A g-1 with a splendid rate capacity of 876 C g-1 (1752 F g-1) at 20 A g-1. Moreover, a device assembled by Ni2P/Co3O4/N-CQDs hierarchical flower-like architecture and p-phenylenediamine functionalized reduced graphene oxide (PPD/rGO) nanosheets depicts a commendable energy density of 53.5 Wh kg-1 at 772.9 W kg-1. This work provides a novel hierarchical multi-component electrode material with decent electrochemical capacities for hybrid supercapacitors, which has a broad prospect in energy storage devices.

14.
Adv Healthc Mater ; 10(6): e2001666, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33448152

RESUMO

Photodynamic therapy (PDT) efficacy has been dramatically limited by the insufficient oxygen (O2 ) level in hypoxic tumors. Although various PDT nanosystems have been designed to deliver or produce O2 in support of reactive oxygen species (ROS) formation, the feature of asynchronous O2 generation and ROS formation still results in the low PDT efficacy. Herein, thylakoid membranes (TM) of chloroplasts is decorated on upconversion nanoparticles (UCNPs) to form UCTM NPs, aiming at realizing spatiotemporally synchronous O2 self-supply and ROS production. Upon 980 nm laser irradiation, UC NPs can emit the red light to activate both photosystem-I and photosystem-II of TM, the Z-scheme electronic structure of which facilitates water to produce O2 and further to singlet oxygen (1 O2 ). UCTM NPs showed excellent biocompatibility, and can effectively remove the hypoxic tumor of mice upon 980 nm laser irradiation. This study develops a new PDT strategy for hypoxic tumor therapy based on photosynthesis.


Assuntos
Nanopartículas , Neoplasias , Fotoquimioterapia , Animais , Camundongos , Neoplasias/tratamento farmacológico , Oxigênio , Fármacos Fotossensibilizantes/uso terapêutico , Oxigênio Singlete , Tilacoides
15.
ACS Appl Mater Interfaces ; 13(17): 19825-19835, 2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-33881837

RESUMO

Tumor-associated macrophages (TAMs) of M2 phenotype have mediated the immunosuppression in a tumor microenvironment, facilitating the escape of tumor cells from immunosurveillance. Reprograming the immunosuppressive M2 TAMs to immunostimulatory M1 phenotype can activate the antitumor immune responses for cancer immunotherapy. Herein, hollow iron oxide (Fe3O4) nanoparticles (NPs) were employed to reprogram M2 TAMs toward M1 TAMs, aiming to release proinflammatory cytokines and recruit T cells to kill tumor cells. After loaded with l-arginine (l-Arg) and sealed with poly(acrylic acid) (PAA), hollow Fe3O4 NPs were fabricated into LPFe3O4 NPs, which could release l-Arg based on pH-responsive PAA and produce nitric oxide (NO) with the help of nitric oxide synthase (iNOS) overexpressed by M1 TAMs, as a result of additional tumor elimination for gas therapy. In vitro and in vivo studies demonstrate that LPFe3O4 NPs could effectively reprogram M2 to M1 macrophages, activating T cells, releasing TNF-α, and producing high levels of NO, leading to synergistic tumor therapy.


Assuntos
Arginina/administração & dosagem , Gases/química , Imunoterapia/métodos , Macrófagos/imunologia , Nanopartículas de Magnetita/química , Nanopartículas de Magnetita/uso terapêutico , Neoplasias/tratamento farmacológico , Microambiente Tumoral , Resinas Acrílicas/química , Animais , Humanos , Macrófagos/enzimologia , Macrófagos/metabolismo , Camundongos , Neoplasias/imunologia , Neoplasias/patologia , Óxido Nítrico/biossíntese , Óxido Nítrico Sintase/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
16.
PLoS One ; 16(3): e0247980, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33657174

RESUMO

Japanese encephalitis (JE) is an acute infectious disease caused by the Japanese encephalitis virus (JEV) and is transmitted by mosquitoes. Meteorological conditions are known to play a pivotal role in the spread of JEV. In this study, a zero-inflated generalised additive model and a long short-term memory model were used to assess the relationship between the meteorological factors and population density of Culex tritaeniorhynchus as well as the incidence of JE and to predict the prevalence dynamics of JE, respectively. The incidence of JE in the previous month, the mean air temperature and the average of relative humidity had positive effects on the outbreak risk and intensity. Meanwhile, the density of all mosquito species in livestock sheds (DMSL) only affected the outbreak risk. Moreover, the region-specific prediction model of JE was developed in Chongqing by used the Long Short-Term Memory Neural Network. Our study contributes to a better understanding of the JE dynamics and helps the local government establish precise prevention and control measures.


Assuntos
Vírus da Encefalite Japonesa (Espécie)/isolamento & purificação , Encefalite Japonesa/epidemiologia , Animais , Culex/virologia , Encefalite Japonesa/transmissão , Humanos , Umidade , Conceitos Meteorológicos , Mosquitos Vetores/virologia , Prevalência , Fatores de Risco , Estações do Ano , Temperatura
17.
Artigo em Inglês | MEDLINE | ID: mdl-31936708

RESUMO

Dengue fever (DF) is one of the most rapidly spreading diseases in the world, and accurate forecasts of dengue in a timely manner might help local government implement effective control measures. To obtain the accurate forecasting of DF cases, it is crucial to model the long-term dependency in time series data, which is difficult for a typical machine learning method. This study aimed to develop a timely accurate forecasting model of dengue based on long short-term memory (LSTM) recurrent neural networks while only considering monthly dengue cases and climate factors. The performance of LSTM models was compared with the other previously published models when predicting DF cases one month into the future. Our results showed that the LSTM model reduced the average the root mean squared error (RMSE) of the predictions by 12.99% to 24.91% and reduced the average RMSE of the predictions in the outbreak period by 15.09% to 26.82% as compared with other candidate models. The LSTM model achieved superior performance in predicting dengue cases as compared with other previously published forecasting models. Moreover, transfer learning (TL) can improve the generalization ability of the model in areas with fewer dengue incidences. The findings provide a more precise forecasting dengue model and could be used for other dengue-like infectious diseases.


Assuntos
Aprendizado Profundo , Dengue/epidemiologia , Previsões , Cidades/epidemiologia , Surtos de Doenças , Humanos , Incidência , Redes Neurais de Computação
18.
Dalton Trans ; 49(44): 15682-15692, 2020 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-33124630

RESUMO

The synthesis of competitive, affordable and sustainable electrocatalysts via simple and scalable methods is highly desirable for the oxygen evolution reaction (OER). Usually, expensive, complex, time-consuming methods are applied to prepared suitable electrocatalysts for the OER. In contrast, a single-step thermal method is simple and inexpensive. Nickel and iron-based composite materials are potential candidates as OER catalysts. Accordingly, herein, Se-doped Fe2O3-decorated Ni/NiO particles on carbon cloth (Se-Fe2O3@Ni/NiO/CC) were synthesized via a facile and scalable one-step thermal method. The individual Se-Fe2O3@Ni/NiO particles were accommodated in holes in the carbon fibers of CC. The optimized Se-Fe2O3@Ni/NiO/CC-2 sample exhibited an outstanding OER performance with an overpotential of 205 mV at the current density 10 mA cm-2, small Tafel slope of 36 mV dec-1, and good stability in 1.0 M KOH electrolyte. The outstanding catalytic performance was mainly attributed to the heterointerfaces between Se-Fe2O3 and Se-Ni/NiO. Moreover, the accommodation of the Se-Fe2O3@Ni/NiO particles in the holes of CC restricted the aggregation of the particles, and CC provided a conductive substrate for the OER process. Thus, this work provides a simple, scalable and effective strategy for designing and engineering of outstanding electrocatalysts for the OER.

19.
J Colloid Interface Sci ; 567: 28-36, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32035391

RESUMO

The development of novel high volumetric capacity electrode materials is crucial to the application of lithium-ion batteries (LIBs) in miniaturized consumer electronics. In this work, a novel tungsten-based octahedron (CoWO4/Co3O4) with unique hierarchical core-shell structure is successfully fabricated by simply calcinating a cyanide-metal framework precursor. Benefitting from the heavy element W, the CoWO4/Co3O4 octahedrons show a high mass density of 5.18 g cm-3. When applied as anode materials for LIBs, the CoWO4/Co3O4 octahedrons exhibit an ultrahigh volumetric capacity (6226 mAh cm-3 after 350 cycles at 0.4 A g-1), superior rate capability (3165 mAh cm-3 at 3.0 A g-1) and outstanding long-term cycling performance (4703 mAh cm-3 at 1.0 A g-1 after 800 cycles). The extraordinary lithium storage performance can be ascribed to the unique hierarchical core-shell structure and the possible synergistic effect between W and Co, which provide more Li+ insertion sites and effectively buffer the volume variation during cycling. This work not only provides an ultrahigh volumetric lithium storage anode, but also gives a simple and general strategy for the synthesis of novel anode materials for high volumetric energy density LIBs.

20.
Adv Mater ; 32(11): e1908109, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32022983

RESUMO

Photodynamic therapy (PDT) efficacy has been severely limited by oxygen (O2 ) deficiency in tumors and the electron-hole separation inefficiency in photosensitizers, especially the long-range diffusion of O2 toward photosensitizers during the PDT process. Herein, novel bismuth sulfide (Bi2 S3 )@bismuth (Bi) Z-scheme heterostructured nanorods (NRs) are designed to realize the spatiotemporally synchronous O2 self-supply and production of reactive oxygen species for hypoxic tumor therapy. Both narrow-bandgap Bi2 S3 and Bi components can be excited by a near-infrared laser to generate abundant electrons and holes. The Z-scheme heterostructure endows Bi2 S3 @Bi NRs with an efficient electron-hole separation ability and potent redox potentials, where the hole on the valence band of Bi2 S3 can react with water to supply O2 for the electron on the conduction band of Bi to produce reactive oxygen species. The Bi2 S3 @Bi NRs overcome the major obstacles of conventional photosensitizers during the PDT process and exhibit a promising phototherapeutic effect, supplying a new strategy for hypoxic tumor elimination.


Assuntos
Bismuto/uso terapêutico , Neoplasias/tratamento farmacológico , Oxigênio/metabolismo , Fármacos Fotossensibilizantes/uso terapêutico , Espécies Reativas de Oxigênio/metabolismo , Sulfetos/uso terapêutico , Animais , Bismuto/química , Linhagem Celular Tumoral , Camundongos , Nanotubos/química , Neoplasias/metabolismo , Fotoquimioterapia , Fármacos Fotossensibilizantes/química , Sulfetos/química , Hipóxia Tumoral/efeitos dos fármacos
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