Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 67
Filtrar
Filtros adicionais











País/Região como assunto
Intervalo de ano
1.
J Nanosci Nanotechnol ; 20(2): 692-700, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31383064

RESUMO

Fluorescent bimetallic Au-Ag nanoclusters (Au-AgNCs) were found to exhibit oxidase-like activity and could catalyze the oxidation of 3,3',5,5' tetramethylbenzidine (TMB) to oxTMB. On the basis of this property, we assembled a fluorescent nanoplatform as a turn-on probe for sensing mercury (II) ions (Hg2+) through the inner-filter effect (IFE). Au-AgNCs and oxTMB were chosen as IFE absorber and fluorophore pair for the first time. In the absence of Hg2+, the Au-AgNCs absorption band well. Covered the fluorescence emission band of oxTMB, and as a result, the fluorescence of oxTMB was reduced. In the presence of Hg2+, Hg2+ was reduced to Hg0 by extra BSA in Au-AgNCs probe system and anchored on the surface of Au-AgNCs. The absorption intensity for Au-AgNCs then decreased at 418 nm, resulting in the recovery of fluorescence from oxTMB. The formed Au-Hg thin amalgam layer obviously enhanced the oxidase-like activity of Au-AgNCs as well as hindered the IFE activity between Au-AgNCs and oxTMB. Therefore, based on the Hg2+ stimulating oxidaselike properties of Au-AgNCs, a fluorometric assay for determination of Hg2+ was developed in this study. The proposed sensing strategy showed a linear range from 10 nM to 500 nM, with ultralow LOD of ~0.7 nM for Hg2+. Moreover, the detection probe system was stable over a wide pH range, making it able to be applied in complex sample systems. We have successfully demonstrated the detection of Hg2+ in tap water samples. The fluorescent assay reported here, for sensitive and selective determination of Hg2+, may find great application in multiple areas, such as environmental and pharmaceutical analysis.

2.
Br J Pharmacol ; 2019 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-31290152

RESUMO

The pharmacological potential of nanotechnology, especially in drug delivery and bioengineering, has developed rapidly in recent decades. Ion channels, which are easily targeted by external agents, such as nanomaterials (NMs) and synthetic drugs, due to their unique structures, have attracted increasing attention in the fields of nanotechnology and pharmacology for the treatment of ion channel-related diseases. NMs have significant effects on ion channels, and these effects are manifested in many ways, including changes in ion currents, kinetic characteristics and channel distribution. Subsequently, intracellular ion homeostasis, signalling pathways, and intracellular ion stores are affected, leading to the initiation of a range of biological processes. However, the effect of the interactions of NMs with ion channels is an interesting topic that remains obscure. In this review, we have summarized the recent research progress on the direct and indirect interactions between NMs and ion channels and discussed the related molecular mechanisms, which are crucial to the further development of ion channel-related nanotechnological applications.

3.
ACS Appl Mater Interfaces ; 11(23): 20778-20787, 2019 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-31117435

RESUMO

Although most metal-organic coordination materials are promising materials used as templates to develop highly efficient electrocatalysts via pyrolysis in situ, few studies have explored the use of these materials for direct catalysis of oxygen evolution reaction (OER). Herein, inspired by the natural synthesis and the inherent properties of metal-organic coordination materials, the FeNi-tannic acid coordination crystal was in situ grown on Ni foam ((FeNi)-Tan/NF) to directly catalyze the OER. It was found that (FeNi)-Tan/NF exhibited predominant OER activity, which required a low overpotential of 208 mV to reach a current density of 50 mA·cm-2 under a small Tafel slope of 33.5 mV·dec-1, and it possessed robust stability. Density functional theory (DFT) calculations demonstrated that the active site change from Ni in Ni-Tan to the Fe atom in (FeNi)-Tan may provide a more favorable OER catalytic route. This application of such polyphenol coordination materials is promising for stimulating the exploration of functional metal-organic coordination materials toward applications in the energy conversion field.

4.
ACS Appl Mater Interfaces ; 11(20): 18782-18796, 2019 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-31059228

RESUMO

Mixed-matrix membranes (MMMs) have been drawing increasing attention due to the high permeability and high rejection capabilities for highly efficient wastewater treatment applications. Nonetheless, improving the water permeance while maintaining the high rejection capability is still an ongoing challenge for the practically state-of-the-art MMMs. Herein, a new class of poly(ether sulfone) (PES) based MMM containing metal-organic framework (MOF) nanofillers of HKUST-1 and blending with poly(methyl methacrylate- co-methacrylic acid) (PMMA- co-MAA) copolymer, designated as HKUST-1@mPES MMM, were developed for the highly efficient ultrafiltration (UF) process. In this study, the nanosized HKUST-1 nanofillers were removed by water dissolution as sacrificial templating materials, so that the additional nanovoids were deliberately generated throughout the dense polymer matrix. The introduction of PMMA- co-MAA copolymer facilitated the even dispersion of HKUST-1 nanofillers in a polymer matrix, by constructing the bridge connection between inorganic nanofillers and organic matrix. The resultant HKUST-1@mPES MMM exhibited a high pure water permeability (PWP) up to 490 L·m-2·h-1·bar-1, substantially reaching nearly 3 times higher than that of the mPES membrane without HKUST-1 nanofillers loading and maintaining a relatively high BSA rejection rate of 96% without obvious deterioration. The newly developed HKUST-1@mPES MMM thereby exhibited a comparable separation efficiency compared to the cutting-edge UF membranes reported so far. Overall, the nanovoid-generated approach provides new insight into developing advanced MMMs used for highly efficient water treatment applications.

5.
Huan Jing Ke Xue ; 40(3): 1287-1294, 2019 Mar 08.
Artigo em Chinês | MEDLINE | ID: mdl-31087976

RESUMO

It is of great significance to analyze the runoff pollution load characteristics of different roof materials to improve the estimation accuracy of urban non-point source pollution loads. Yangzhou City was selected as the study area. There, three types of roofs were chosen for rainfall-runoff monitoring, including a Chinese style tile roof, cement tile roof, and concrete flat roof. The pollutant concentrations, scour law, and first flush effect of the three types of roofs were compared. The results show that the event mean concentration (EMC) of total nitrogen (TN), total phosphorus (TP), permanganate index, and total suspended solids (TSS) in the runoff of Chinese style tile roofs are around 4-9 times that in the runoff of cement tile roofs. The rainfall intensity exhibits stronger effect on the change in pollutant concentrations of runoff from the Chinese style tile roof than that from the cement tile roof. The Pearson correlation coefficients (r) of rainfall intensity against TP and TSS in time series were 0.853 and 0.822, respectively. The first flush intensities of the three types of roof materials were in the order cement tile roof > concrete flat roof > Chinese style tile roof. It was found that 60.0% of the roof runoff pollution load could be reduced by intercepting 31.5%, 58.0%, and 60.4% of the initial runoff for the Chinese style tile roof, the cement tile roof, and the concrete flat roof, respectively. The actual emissions of TN, TP, and TSS, and the permanganate index in rainstorm events would be significantly underestimated when roof materials are not distinguished. This would have negative effects on the pollution control of urban non-point sources. It is demonstrated that the fine distinction of roof materials is able to improve the estimation accuracy of urban non-point source loads.

6.
Appl Ergon ; 78: 164-175, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31046948

RESUMO

Scientific developments have enabled the application of virtual reality (VR) technology in various fields. However, this technology is disadvantaged by low recognition, existence of bias, lack of precision, and fatigue of text input in VR environments. To address these problems, this study proposed a spatial enhancement technique. This study investigated the effectiveness of spatial enhancement keys of a virtual keyboard from various angles and explored the impact of enhanced response time and enhanced protrusion distance on the spatial enhancement technology. Finally, the following conclusions are obtained: (1) The average text input performance of the keyboard using the spatial enhancement technique is significantly better than that of the ordinary virtual keyboard without using the spatial enhancement technique. (2) The recommended time interval for enhanced response time and the protrusion distance are 0-100 ms and 1.85 diopter, respectively. The keyboard angle insignificantly affects the input through the keyboard performance.

7.
Sci Total Environ ; 683: 427-435, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31141745

RESUMO

Aquaculture accounts for an extremely valuable and rapidly expanding sector of global food production, yet its environmental impacts on aquatic ecosystems have attracted much concern. In this study, we collected water samples from eastern Lake Taihu, China. We targeted sites varying in their intensity of aquacultural activities and sampled them over multiple seasons. For each sample, we measured physicochemical variables, and we sequenced the 16S rRNA gene of the respective bacterial communities using an Illumina second-generation sequencing platform. Marked differences in diversity and bacterial community composition were observed between seasons, whereas we observed relatively weak differences between sites. Remarkable differences in the abundance of the bacterial community were observed at the phylum and genus levels across the different seasons. Stochastic processes dominated the assembly of bacterial communities in the aquaculture-influenced systems, and the assembly processes of bacterial community differed between seasons. Our observations highlight the effect of seasonality on bacterial communities and provide a more complete knowledge base for the proper assessment of the effects of aquacultural activities on freshwater ecosystems.


Assuntos
Aquicultura/estatística & dados numéricos , Monitoramento Ambiental , Lagos/microbiologia , Poluição da Água/análise , Estações do Ano , Microbiologia da Água
8.
Small ; 15(5): e1804421, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30556342

RESUMO

A noncontact method that can achieve immobilization, transportation, and rotation in the microscale is desired in biological micromanipulation. A multifunctional noncontact micromanipulation method is proposed here based on a vibration-generated whirling flow. Resonance of a cantilever structure is utilized to extend the straight vibration of a single piezo actuator to the 2D circular vibration of a micropipette. The circular vibration in fluids can generate the whirling flow featured with low pressure in the core area and flow velocity gradient. The low pressure can immobilize the objects nearby and transport them together with the micropipette, and the flow velocity gradient is utilized to form a torque to rotate the immobilized object. Experiments of the microbeads are conducted to evaluate the claimed functions and quantify the key parameters that influence the rotation velocity. The cell spheroid is immobilized and rotated for 3D observation, and by assessing the viability of the cells containing in the spheroid, the proposed method is proved noninvasive to living cells. Finally, another important application in operations of mouse egg cells is shown, which indicates that the proposed method is a potential valuable tool in biological micromanipulation.

9.
Front Microbiol ; 9: 2298, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30327642

RESUMO

Non-toxigenic Bacteroides fragilis is regarded as a potential candidate for probiotic owing to its various advantages. We previously isolated a new strain of B. fragilis (ZY-312) and verified its biosafety and capability of inhibiting the growth of pathogens in vivo. However, the colonization of ZY-312 in gastrointestinal (GI) tract remains to be determined. To track the colonization of ZY-312, mice were gavaged with ZY-312 labeled by means of metabolic oligosaccharide engineering and bioorthogonal click chemistry or given AF647-dibenzocyclooctyne (DIBO) directly. Then the fluorescence was detected in GI tract, spleen and kidneys. Results showed that ZY-312 could be labeled by metabolic oligosaccharide engineering, and the optimal incubation time with AF647-DIBO was 5 h in vitro. Following oral gavage with AF647-DIBO labeled ZY-312 or AF647-DIBO alone, mice were subjected to in vivo imaging and the fluorescence intensity was similar in both groups 3 h, 6 h, and 12 h post the gavage. The fluorescence of AF647-DIBO group disappeared 24 h post gavage which was probably due to the excretion via GI tract. While the fluorescence of AF647-DIBO labeled ZY-312 retained in the cecum for as long as 48 h. Immunofluorescence assay further confirmed that labeled ZY-312 transiently colonized not only in cecum but also in stomach, ileum and colon of mice 48 h post-gavage and that no massive accumulation of ZY-312 was detected in other organs such as kidneys and spleen. In conclusion, ZY-312 could transiently colonize in GI tract, mainly in cecum, for at least 48 h, and it hardly disseminate to other organs, which shed new light on the future development of B. fragilis as a probiotic product.

10.
Nanoscale ; 10(43): 20354-20365, 2018 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-30376015

RESUMO

Recently, mesoporous silica nanoparticles (MSNs) have become popular nanomaterials in smart delivery systems. Although research progress in the application of MSNs as pesticide carriers has been achieved, multifunctional MSNs endowed with bright luminescent centers facilitating the tracking of MSNs in biological systems and versatile structural properties possessing a high drug loading capacity and regulable release are still highly desirable. In the present work, we reported a fluorophore-free method to endow MSNs with stable fluorescence and a double-shelled hollow structure; they were prepared by a selective-etching strategy and subsequent annealing treatment. The strong and stable luminescence is found to originate from the carbon dots generated from the calcination. Their well-defined morphological structure was confirmed by SEM and TEM imaging. These versatile silica nanoparticles served as a novel delivery system for the pesticide pyraclostrobin with a loading content of 28.5%. The pyraclostrobin-loaded nanoparticles showed an initial burst, followed by subsequent sustained release behavior. The fungicidal activity of pyraclostrobin-loaded silica nanoparticles against the fungus Phomopsis asparagi (Sacc.) as well as their visual observation in the mycelium was explored. Furthermore, the effect of pyraclostrobin-loaded nanoparticles on the morphology and ultrastructure of the mycelium was investigated by SEM and TEM observations. This research seeks to develop a novel nanocarrier platform for the potential application of pesticides in sustainable plant protection.

11.
J Nanosci Nanotechnol ; 18(12): 8269-8275, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-30189946

RESUMO

In this study, hierarchical ternary nanocomposites, i.e., Cu-TiO2-mesoporous silica microspheres (Cu-TiO2-MSM), were synthesized as ternary photocatalyst system to improve the visible light photocatalytic degradation of the environmental pollutant model dye methylene blue (MB). The innovation of this method is in situ depositing TiO2 and Cu2O nanoparticles sequentially onto the surface of mesoporous silica microspheres to form highly active heterostructure. The improved activity for the degradation of MB is attributed to: (1) the high adsorption capacity of the porous and interconnected-channel-structure MSM to MB; (2) the valence band electrons of TiO2 released from the conduction band generating abundant highly active free radicals, which directly reacted with adsorbed MB. The photocatalytic degradation efficiency to MB was found to be 98% in 5 min, and almost 100% in 20 min. This study paves a way for the development of a ternary-doped catalyst for visible light photocatalytic degradation and may exhibit widely application in industry.

12.
J Nanosci Nanotechnol ; 18(12): 8289-8295, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-30189949

RESUMO

To facilely develop low-cost and efficient hydrogen evolution electrocatalysts, catalyst with low content of platinum on nitrogen-doped carbon nanoporous structures were prepared for hydrogen evolution reaction (HER). This study firstly demonstrated the one-step pyrolysis transformation of conveniently accessible mulberry leaves to obtain nitrogen-doped nanoporous carbons (N-NPCs) for hydrogen evolution reaction. After electrochemical treatment, the obtained N-NPCs-ET with Pt as counter electrode exhibited an unexpected high hydrogen evolution activity, which had low onset overpotential of 100 mV and a Tafel slope of 60 mV dec-1. N-NPCs-ET maintained catalytic activity for at least 10 h in 0.5 M H2SO4 solution. The enhanced HER performance was relevant to the incorporation of Pt nanoparticles, which were dissolved from anodic Pt counter electrode in acid media and precipitated into cathodic N-NPCs surface again. Moreover, for the first time, we found that with a gold electrode as the counter electrode, Au nanoparticles could be incorporated into N-NPCs by electrochemical treatments and the formed Au nanoparticles decorated N-NPCs possessed efficient catalytic activity toward HER.

13.
ACS Appl Mater Interfaces ; 10(38): 32567-32578, 2018 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-30169014

RESUMO

In this study, we present a three-in-one catalytic platform for intrinsic oxidase-, peroxidase-, and catalase-like activity, which is enabled by epitaxial growth of the MoS x nanosponge on 2D Co(OH)2 nanoflakes [2D Co(OH)2 NFs] (CoMo hybrids). First, the 2D Co(OH)2 NFs are stripped from hierarchical three-dimensional Co(OH)2 nanoflowers which are synthesized in an eco-friendly way via one-step surfactant-free chemical route. Next, the porous MoS x nanosponge is decorated on the 2D Co(OH)2 NFs' surface using a solvothermal process forming heterogeneous nanostructured CoMo hybrids. Finally, because of the host-guest interaction, that is, after the epitaxial growth of spongy MoS x on 2D Co(OH)2 NFs, the heterogeneous nanostructure of CoMo hybrids exhibits unpredictable triple-enzyme mimetic activity simultaneously. The mechanisms of the oxidase-like properties are investigated by density functional theory (DFT) calculations, and it is discovered that a simple reaction/dissociation of O2 absorbed on Co-Mo thin films can explain the enhanced oxidase-like activity of the CoMo hybrids. In addition, the CoMo hybrids are also reproducible, stable, and reusable, that is, after 10 cycle uses, >90% mimic enzyme activity of the CoMo hybrids is still maintained. The oxidase-like activity of the CoMo hybrids enables it to oxidize 3,3',5,5'-tetramethylbenzidine (TMB) producing the blue oxTMB, which can selectively oxidize ascorbic acid (AA) and pave a new avenue for colorimetric sensing of AA. The proposed colorimetric strategy has been successfully utilized to measure AA in rat brain during the cerebral calm/ischemia process. Our findings provide in-depth insight into the future research of enzyme-like activities and might help to elucidate the mechanism and understand the role of epitaxial growth on the properties and application of hybrid nanostructures.

14.
J Sep Sci ; 41(18): 3622-3630, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30033678

RESUMO

An adsorbent of carbon dot@poly(glycidyl methacrylate)@Fe3 O4 nanoparticles has been developed for the microwave-assisted magnetic solid-phase extraction of polycyclic aromatic hydrocarbons in environmental aqueous samples prior to high-performance liquid chromatography with UV/visible spectroscopy detection. Poly(glycidyl methacrylate) was synthesized by atom transfer radical polymerization. The chain length and amount of carbon dots attached on them can be easily controlled through changing polymerization conditions, which contributes to tunable extraction performance. The successful fabrication of the nano-adsorbent was confirmed by transmission electronic microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and vibrating sample magnetometry. The extraction performance of the adsorbent was evaluated by using polycyclic aromatic hydrocarbons as model analytes. The key factors influencing the extraction, such as microwave power, adsorption time, desorption time and desorption solvents were investigated in detail. Under the optimal conditions, the microwave-assisted method afforded magnetic solid-phase extraction with short extraction time, wide dynamic linear range (0.02-200 µg/L), good linearity (R2  ≥ 98.57%) and low detection limits (20-90 ng/L) for model analytes. The adsorbent was successfully applied for analyzing polycyclic aromatic hydrocarbons in environmental aqueous samples and the recoveries were in the range of 86.0-124.2%. Thus, the proposed method is a promising candidate for fast and reliable preconcentration of trace polycyclic aromatic hydrocarbons in real water samples.

15.
Sensors (Basel) ; 18(7)2018 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-29932124

RESUMO

The demand for a harmless noncontact trapping and transportation method in manipulation and measurement of biological micro objects waits to be met. In this paper, a novel micromanipulation method named “Hydrodynamic Tweezers” using the vortex induced by oscillating a single piezoelectric actuator is introduced. The piezoelectric actuator is set between a micropipette and a copper beam. Oscillating the actuator at a certain frequency causes the resonance of the copper beam and extend 1D straight oscillation of the piezoelectric actuator to 2D circular oscillation of the micropipette, which induces a micro vortex after putting the micropipette into fluid. The induced vortex featuring low pressure in its core area can trap the object nearby. A robotic micromanipulator is utilized to transport the trapped objects together with the micropipette. Experiments of trapping and transportation microbeads are carried out to characterize the key parameters. The results show that the trapping force can be controlled by adjusting peak-peak voltage of the sinusoidal voltage input into the piezoelectric actuator.

16.
Anal Chem ; 90(12): 7158-7163, 2018 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-29799730

RESUMO

We developed a simple and environmentally friendly ultraviolet (UV)-irradiation-assisted technique to fabricate a stretchable, nanostructured gold film as a flexible electrode for the detection of NO release. The flexible gold film endows the electrode with desirable electrochemical stability against mechanical deformation, including bending to different curvatures and bearing repeated bending circumstances (200 times). The flexible nanostructured gold electrodes can catalyze NO oxidation at 0.85 V (as opposed to Ag/AgCl) and detect NO within a wide linearity in the range of 10 nM to 1.295 µM. Its excellent NO-sensing ability and its stretchability together with its biocompatibility allows the electrode to electrochemically monitor NO release from mechanically sensitive HUVECs in both their unstretched and stretched states. This result paves the way for an effective and easily accessible platform for designing stretchable and flexible electrodes and opens more opportunities for sensing chemical-signal molecules released from cells or other biological samples during mechanical stimulation.

17.
Mikrochim Acta ; 185(2): 131, 2018 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-29594579

RESUMO

The authors report that cobalt oxyhydroxide (CoOOH) nanoflakes possess intrinsic oxidizing ability to directly oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to form a blue colored product (oxTMB) even in the absence of H2O2 and oxygen. In the presence of ascorbic acid (AA), less of the blue product is formed because AA reduces oxTMB. These findings constitute a new scheme for colorimetric detection of AA. Absorbance, best measured at 652 nm, linearly drops in the 10 nM to 1 µM AA concentration range, and the limit of detection is 5 nM (at an S/N ratio of 3). The reaction is complete within <5 s and highly selective. A strip test has been designed for fast and on-spot visual detection of AA. The method was applied to the direct estimation of AA in the microdialysate of brain, and also in soft drink samples. The strip test is considered to be a promising tool for the rapid screening of AA in brain and commercial samples. Graphic abstract Schematic of the CoOOH-TMB colorimetric system that exhibits a high selectivity for ascorbic acid (AA). A strip test has been designed for fast and on-spot visual detection of AA.

18.
Environ Sci Technol ; 51(18): 10379-10386, 2017 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-28841303

RESUMO

An innovative approach was developed to reveal phosphorus (P) transport and redistribution in large and complex river networks in the Lake Taihu basin by establishing the relations between sediment P spatial distribution and P sorption behavior on particles with different grain size, sorted by hydrodynamics. The sediment P fractionation composition changed greatly across the basin, where 69% consisted of acid-soluble fractions (HCl-P) in upstream rivers while 70% was in fractions associated with reducible metal hydroxides (BD-P) and amorphous hydroxides (NaOH25-P) in downstream rivers. Fine particles enriched in BD-P and NaOH25-P fractions tended to sorb liberated P during the resuspension process, and fine particles were more easily delivered downstream toward the lake, forming a sieved transport of P in the river networks. This will lead to a great potential for sediment P release when environmental anoxia develops in the sediments or high pH occurs in the sediment surface during intensive algal blooms in the shallow lake. Reduction of external P from point sources from urbanized areas is an important requirement at the basin scale; however, long-term efforts are needed to restore aquatic macrophytes in the lake, which would decrease P recycling rates at the water-sediment interface.


Assuntos
Lagos , Fósforo , Rios , Poluentes Químicos da Água , China , Monitoramento Ambiental , Sedimentos Geológicos
19.
Anal Chem ; 89(17): 8683-8688, 2017 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-28787575

RESUMO

We report a novel ultrasonic-aided fast and straightforward approach to fabricate Au microelectrodes by electroless deposition of nanostructured gold films on the rigid outer surface of pulled glass capillaries. Microelectrodes with tip diameters ranging from several hundred nanometers to several micrometers were fabricated within 20 min via three sequential ultrasonication steps. The ultrasonication technique has been validated to be a very effective route in engineering the morphology of Au film surfaces and improves the fabrication efficiency of Au microelectrodes. The nanostructured surfaces of the Au microelectrodes demonstrate excellent sensing activity and antifouling for dopamine oxidation. The microelectrodes were applied for measurement of catecholamines released from exocytosis events from single chromaffin cells and exhibited faster dynamic peak parameters, compared with carbon fiber microelectrodes. This report provides a generally accessible and complementary platform for analyzing catecholamines release events, which should be useful for new electrode designs and neurochemical sensing.

20.
J Chem Phys ; 146(12): 124108, 2017 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-28388109

RESUMO

The Berendsen barostat from molecular dynamics simulation is applied in both standard dissipative particle dynamics (DPD) and many-body dissipative particle dynamics (MDPD) simulations. The original Berendsen barostat works well in (M)DPD simulation of a single-component system under constant pressure condition and in nonequilibrium dynamic processes. The partial Berendsen barostat is proposed for multi-component system simulation with (M)DPD. The displacement rescaling process of the Berendsen barostat is only applied on the particles outside the center region, acting as a pressure "boundary condition." The center part forms the free zone, in which the interface shape and nonequilibrium dynamic behavior between different phases can be captured properly. An immiscible bubble in the second fluid under constant pressure condition is studied, and the oscillation of the bubble radius and fluctuation of systempressure can be obtained by the current barostat. Preliminary models for bubble growing and collapsing under square pressure wave and bubble oscillation under harmonic pressure wave are also reported in the current simulation. It shows that the partial Berendsen barostat is suitable for the modeling of nonequilibrium process of single or few droplets/bubbles in multi-component systems.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA