A composite, reduced graphene oxide (rGO) doped with silver nanoparticles (Ag NPs), was prepared by using binary reductants of sodium citrate and hydrazine hydrate. Carbon quantum dots (CQDs) ...synthesized by papaya peel combined with silver ions to form a CQDs-loaded silver nanoparticle (AgCQDs) nanocomposite. Polymer nanospheres (PNS) were generated via the infinite coordination polymer of ferrocene dicarboxylic acid and employed as carriers to load AgCQDs. The prepared AgCQDs@PNS–PEI has good biocompatibility and electrical conductivity and can be used as a matrix for the immobilization of a secondary antibody (Ab2). A sandwich-type electrochemiluminescence (ECL) immunosensor using AgCQDs@PNS–PEI nanocomposite as probe has been developed for the detection of human chorionic gonadotropin (HCG). The proposed immunosensor exhibits a linear range from 0.00100 to 500 mIU mL
−1
and the detection limit is 0.33 μIU mL
−1
(
S
/
N
= 3) under optimal conditions. The sensor exhibits excellent selectivity, good reproducibility, and high stability. These features demonstrate that the proposed method has promising potential for clinical protein detection and displays a new strategy to fabricate an immunosensor.
Graphical abstract
•A novel polyimide/functionalized graphene composite matrix with double bond (GPI/AMG) was synthesized.•Cross-linked nanocomposite films based on GPI/AMG were prepared by using UV-curing ...technology.•The interaction between AMG and GPI matrix and the cross-linked structure improved the performance of the UV-cured films.
Polyimide/amino-modified reduced graphene oxide (PI/AMG) composite matrix were synthesized through the condensation reaction of 4,4'-diaminodiphenyl ether, 3,5-diaminobenzoic acid, diphthalic anhydride, and AMG. Subsequently, the double bonds were incorporated into the matrix through the reaction of glycidyl methacrylate (epoxide group) and the carboxyl group on PI/AMG. UV-cured composite films were then prepared and performance was evaluated. The results revealed that the tensile strength and elongation at break could reach a maximum of 108.7 MPa and 46.4%, which represented increases of 102.8% and 354.9%, respectively, compared with the GPI/AMG0% film. The water absorption decreased from 0.64% to 0.27%. And their surface resistivity reached 106–109 Ω, an increase of approximately eight orders of magnitude.
KrF photoresist polymers (PASTMs) were prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization. Four (meth)acrylates with lithographic functionalities including styrene ...(St), 4-acetoxystyrene (AST), 2-methyl-2-adamantyl methacrylate (MAMA), and tert-butyl acrylate(TBA) were used as monomer components and 2-methyl-2-(dodecylsulfanylthiocarbonyl) sulfanylpropanoic acid (MDFC) was used as RAFT agent, varying the RAFT content could modulate molecular weight. Fourier-transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (
1
H NMR) indicated that the synthesis was successful. Gel permeation chromatography (GPC) showed that the molecular weight decreased with the increased content of MDFC, and all the polymers possessed weight-average molecular weight below ten thousand and polydispersity less than 1.32. Thermogravimetric analysis (TGA) characterized the thermal properties, the results implied that initial thermal decomposition temperature reached 200 °C, which could satisfy the lithography process. Differential scanning calorimetry (DSC) showed that the Tg decreases with molecular weight. The RAFT polymerization kinetics plots demonstrated that the polymerization was first-order, the number-average molecular weights of the polymers with relatively low polydispersity index values increased with total monomer conversions indicating that the concentration of growing radicals was constant throughout the polymerization process. The narrow molecular weight distribution and composition uniformity of the polymers prepared by RAFT polymerization could be beneficial for lithography, after alcoholysis, lithography evaluation under KrF lithography showed that this homogeneous polymer photoresist exhibited better space and line (S/L) pattern with resolution of 0.18 μm according to the SEM image.
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•High quantum yield N-CQDs are synthesized using osmanthus fragrans.•N-CQDs were used as a nanosensor for sensitive and selective determination of QT and Al3+.•The fluorescent ...nanosensor is successfully applied to intracellular QT and Al3+ images.
In this work, fluorescent N-doped carbon quantum dots (N-CQDs) have been synthesized by simple hydrothermal heating of natural osmanthus fragrans, without any toxic ingredients or surface chemical modifications. The N-CQDs possess a high quantum yield of 21.9 %, outstanding blue fluorescence, good water dispersity, and excellent optical stability. Because the favorable inner filter effect (IFE) between N-CQDs and quercetin (QT) occurs, the addition of QT to N-CQDs can cause their fluorescence quenching. When Al3+ was added to the N-CQDs/QT system solution, it was found that the inhibition of IFE leads to the fluorescence intensity of N-CQDs/QT system enhancement by virtue of a specific binding of QT to aluminum ion (Al3+). Therefore, we used the N-CQDs as a novel off-on fluorescent nanosensor to detect QT and Al3+. Under optimal conditions, the fluorescent nanosensor can detect QT within the wide linear response in the range of 0.003−80 μmol/L with as low as 1 nmol/L detection limit. For the detection of Al3+, the N-CQDs/QT system showed linearity response toward Al3+ in a range of 0.1∼100 μmol/L and the limit of detection was found at 26 nmol/L. In addition, N-CQDs have been successfully used to efficient quantification QT in human plasma and monitor Al3+ in serum samples. Noteworthy, the N-CQDs demonstrated low toxicity toward T24 cells, which realized sensing QT and Al3+ in the living cells.
A hydrothermal strategy for preparing boron and nitrogen codoped carbon quantum dots was studied using the precursors of p-amino salicylic acid, boric acid and ethylene glycol dimethacrylate. The ...boron and nitrogen codoped carbon quantum dots have high fluorescence intensity, good monodispersity, high stability, superior water solubility, and a fluorescence quantum yield of 19.6%. Their average size is 5 nm. Their maximum excitation and emission wavelengths are 380 and 520 nm, respectively. Permanganate (MnO4 –) quenched boron and nitrogen codoped carbon quantum dots fluorescence through inner filter effect and static quenching effects. The linear relation between quenching efficiency and MnO4 – concentration ranged from 0.05 to 60 μmol/L with a detection limit of 13 nmol/L. In the presence of captopril, MnO4 – was reduced to Mn2+ and the fluorescence of boron and nitrogen codoped carbon quantum dots was recovered. The linear range between recovery and captopril concentration was from 0.1 to 60 μmol/L. The limit of detection was 0.03 μmol/L. The developed method can be employed as a sensitive fluorescence sensing platform for MnO4 –. It has been successfully used for captopril detection in mouse plasma.
•Yellow fluorescent nitrogen-doped carbon quantum dots were produced by using extract of chlorophyll from lettuce leaf.•The quantum yield of as-synthesized YN-CQDs was up to 38%•An off–on sensing ...method for MZ detection was developed using YN-CQDs/Ag+ as a fluorescent probe.
In this work, bright yellow fluorescent nitrogen-doped carbon quantum dots (YN-CQDs) are produced by a facile, inexpensive and eco-friendly hydrothermal technique using extract of chlorophyll from lettuce leaf as precursor. The quantum yield (QY) of as-synthesized YN-CQDs was up to 38%, which was higher than the previously reported quantum yield of most CQDs prepared using other biomass. Silver ion (Ag+) can covalently bond with carboxyl, hydroxyl and amino groups on the surface of YN-CQDs and quench the fluorescence of YN-CQDs through static quenching. Upon addition of methimazole (MZ) to the YN-CQDs/Ag+ dispersion system, Ag+ releases from the YN-CQDs/Ag+ complex due to the high affinity of MZ for Ag+ and the quenched fluorescence of the YN-CQDs was recovered. Hence, we developed an off–on sensing method for the detection of MZ using YN-CQDs/Ag+ as a fluorescent probe. Under optimal conditions, with addition of MZ, the fluorescence recovery of YN-CQDs/Ag+ system happens with a good linearity in the range of 0.003 ~ 60 μmol/L and a detection limit of 0.8 nmol/L. The YN-CQDs/Ag+ system exhibited good MZ determination performance. The established off–on fluorescence sensing platform was successfully employed for detecting MZ in mouse plasma.
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•Molecular imprinting technique was used to detect SCCA for improving selectivity.•Fe(III)-MIL-88B-NH2 acts as an efficient coreaction accelerator for enhancing sensitivity.•A ...three-way signal amplification strategy for ZnSeQDs emission was developed.
An electropolymerized dopamine molecularly imprinted polymer (MIP) electrochemiluminescence (ECL) biosensor was constructed to detect squamous cell carcinoma antigen (SCCA). Besides having a large surface area, which allows the loading of more ZnSe quantum dots (ZnSeQDs), Fe(III)-MIL-88B-NH2 metal organic framework (MOF) is an efficient co-reaction accelerator that facilitates the transition of S2O82− into SO4−. As a result, the signal probe of Fe(III)-MIL-88B-NH2@ZnSeQDs/Ab has a strong ECL emission, which allowed the development of a three-way signal amplification strategy for ZnSeQDs emission. The electropolymerized dopamine MIP was found to improve the selectivity in the detection of SCCA. Under optimized conditions, the biosensor displayed a wide linear range from 0.0001 to 100 ng mL-1 with a detection limit of 31 fg mL-1. The prepared biosensor showed several advantages, including good specificity, outstanding selectivity and excellent stability. The proposed method can be used for the rapid and sensitive detection of SCCA in human serum and has promise for clinical application.
In most multi-extended target tracking scenarios, the target detection probability is usually unknown and time-varying, which leads to biased estimation of the state and cardinality of extended ...targets in online filtering. In addressing the challenge, this paper presents the unknown detection probability extended target trajectory Poisson multi-Bernoulli mixture (U-TPMBM) filter. Compared to the existing extended target Poisson multi-Bernoulli Mixture (PMBM) filter, the U-TPMBM is firstly based on sets of trajectories, which allows for direct output of target trajectory and can lead to improved trajectory estimation performance. Besides, the U-TPMBM filter integrates the unknown detection probability with the target trajectory state and thus obtains the augmented state space. By recursively estimating the augmented states via multi-target filtering approaches, it successfully realizes online and joint estimates of the unknown detection probability and the target trajectory. Finally, the U-TPMBM filter is implemented by the Beta-Gamma Gaussian Inverse Wishart (BGGIW) mixture method, especially the BGGIW-TPMBM filter. The Beta distribution is utilized to propagate densities of the unknown detection probability and the GGIW distribution to propagate densities of the target trajectory. Based on the BGGIW distribution, the trackers's recursive and closed solutions are derived in detail. The simulation experiments demonstrate that the BGGIW-TPMBM proposed in this paper can achieve robust tracking performance, even when dealing with unknown detection probabilities.
Purpose
This paper aims to investigate the law and logic mechanism of management control matching pattern and company strategy aggressiveness under different strategies by textual analysis, based on ...the empirical data of Chinese A-share listed companies during the period from 2010 to 2018. Additional analyses further investigate the moderating effect of environmental uncertainty and R&D intensity on the relationship between management control matching type and strategy aggressiveness. The conclusion can help relevant departments to develop management control theory and method system with Chinese characteristics and provide theoretical reference for the matching mode of dual control.
Design/methodology/approach
This paper uses the text analysis method. The main explanatory variables are analyzed using the computer SQL Server database software through the relevant text of the board of directors report in the company annual report. Other financial data came from the CSMAR database, excluding ST and PT and companies with missing data, and 16,902 samples were finally obtained. This paper conducted statistical analysis through Stata12.
Findings
This paper shows that the matching pattern between formal and informal control is divided into three types. They have different impacts on strategy aggressiveness. Specifically, consistent matching type II significantly positively influences the aggressiveness of offensive strategy. Consistent matching type I significantly positively influences the aggressiveness of defensive strategy. Complementary matching type I significantly positively influences the aggressiveness of analytical strategy. Additional analyses find that compared with non-high-tech companies, high-tech companies have more significant influence on the relationship between management control matching pattern and company strategic aggressiveness. And compared with other two “strategy-control” matching patterns, both environmental uncertainty and product innovation have more significant influence on the relationship between consistent matching II and offensive strategy aggressiveness.
Originality/value
To the best of the authors’ knowledge, this paper divides the formal and informal control matching patterns of management control into three categories for the first time. It examines the relationship between the formal and informal control matching of management accounting and the degree of strategy aggressiveness. The conclusion provides new empirical evidence to promote the effective implementation of development strategies for companies. It can help relevant departments to develop management control theory and method systems with Chinese characteristics and provide theoretical references for the matching mode of dual control.
An electrochemiluminescence resonance energy transfer (ECL-RET) immunosensor was developed based on the potential-resolved technology for the simultaneous detection of neuron-specific enolase (NSE) ...and the cytokeratin 19 fragment (CYFRA21-1). The absorption spectrum of gold nanorods (AuNRs) perfectly overlapped with the ECL spectra of SnS2@Pt and Ru(bpy)32+/Zn-MOF, so they exhibited an excellent ECL-RET effect with high efficiency. Zn-MOF possesses a large surface area, which allows for the loading of Ru(bpy)32+. This results in a signal probe of Ru(bpy)32+/Zn-MOF/Ab1 showing a strong ECL emission. Simultaneously, owing to the excellent electronic conductivity of PtNPs, they can increase the electron transfer rate between S2O82- and tin disulfide nanoflowers (SnS2NFs). Hence, the ECL signal of SnS2NFs can be enhanced. Under the optimal conditions, the linear range for NSE is 0.2 pg mL-1-20 ng mL-1 with a detection limit of 79 fg mL-1. The linear range for CYFRA21-1 is 1.25 pg mL-1-12.5 ng mL-1 with a detection limit of 0.43 pg mL-1. The proposed immunosensor can be used for the sensitive simultaneous detection of NSE and CYFRA21-1 in human serum and has promise for clinical diagnostics.
