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The enrichment of co-reactants is one of the keys to improving the sensitivity of electrochemiluminescence (ECL) detection. This work developed a novel hydrophobic localized enrichment strategy of co-reactants utilizing the inner hydrophobic cavity of β-cyclodextrin (β-CD). Pt nanoparticles (Pt NPs) were grown in situ on the coordination sites for metal ions of β-CD to prepare the β-CD-Pt nanocomposite, which could not only enrich co-reactant 3-(dibutylamino) propylamine (TDBA) highly efficiently through its hydrophobic cavity but also immobilize TDBA via the Pt-N bond. Meanwhile, the carboxyl-functionalized poly[2,5-dioctyl-1,4-phenylene] (PDP) polymer nanoparticles (PNPs) were developed as excellent ECL luminophores. With SARS-CoV-2 nucleocapsid protein (ncovNP) as a model protein, the TDBA-β-CD-Pt nanocomposite combined PDP PNPs to construct a biosensor for ncovNP determination. The PDP PNPs were modified onto the surface of a glassy carbon electrode (GCE) to capture the first antibody (Ab

The suction force on high-sphericity seeds is important to the design of air-suction seed-metering devices. However, little systematic research has been conducted on the suction force. A self-designed suction force measurement device and idealised model were used to conduct CFD simulation, single factor experiments, and orthogonal experiments to improve the model of the suction force on seeds with sphericity over 90.34% and equivalent diameter 6.63–7.16 mm under the following conditions: suction hole diameter 4–6 mm, suction hole vacuum 3–5 kPa, seed-filling angle ±π/8, and horizontal distance from the seed centre to the suction hole 3.5–5.5 mm. The verification experiment conducted using the seeds of soybean, pea, and Panax notoginseng showed that the accuracy was higher for the improved suction force model. Simulation of flow behaviours under different factors revealed that the changes in the air velocity gradient and pressure gradient are the main causes of the change in the suction force. The relationship between the drag force model and the suction force model was studied by comparing the predicted value of the drag force and the measured value of the suction force under the same conditions.

The electrochemiluminescence (ECL) ratiometric assay is usually based on two different ECL luminophores, and the choice of two suitable luminophores and shared co-reactant makes its construction challenging. The single-emitter-based ECL ratio mode could overcome the limitation of two luminophores and simplify the construction process, so it is an ideal choice. In this work, CdTe quantum dots (CdTe QDs) were modulated using black phosphorus (BP) nanosheet to simultaneously emit the cathodic and anodic ECL signals, and H2O2 and tripropylamine (TPrA) served as the cathodic and anodic co-reactants, respectively. MicroRNA-126 (miRNA-126) was selected as the template target to exploit the application of BP-CdTe QDs in the single-emitter-based ECL ratio detection. Through the target recycling triggering rolling-circle amplification (RCA) reaction, a large amount of glucose oxidase (GOx)-modified single strand 1 was introduced. GOx catalyzed glucose to produce H2O2 in situ, which acted as a dual-role moderator to quench the anodic ECL emission with TPrA as the co-reactant while enhancing the cathodic emission, thereby realizing the ratiometric detection of miRNA-126 with a low detection limit of 29 aM (S/N = 3). The dual-ECL-emitting BP-CdTe QDs with TPrA-H2O2 as dual co-reactant provide a superior ECL ratio platform involving enzyme catalytic reaction, expanding the application of single-emitter-based ratio sensing in the diverse biological analysis.

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The bifunctional moderator is urgently needed in the field of ratiometric electrochemiluminescence (ECL) sensing since it can mediate simultaneously two ECL signals to conveniently realize their opposite change trend. This work designed a novel dual-signal combined nanoprobe with carboxyl-functionalized poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1',3}-thiadazole)] nanoparticles (c-PFBT NPs) as the anodic ECL probe and L-cysteine capped CdS quantum dots (L-CdS QDs) as the cathodic ECL probe, which performed a dual-signal output capability without any additional coreactants. More importantly, hydrogen peroxide (H2O2) produced in situ by enzyme-catalyzed reaction was developed as a bifunctional moderator for simultaneously regulating two signals. The dual-signal combined nanoprobe (c-PFBT NPs@CdS QDs) served as the matrix to immobilize acetylcholinesterase (AChE) and choline oxidase for organophosphorus (OPs) analysis. In the absence of OPs, H2O2 was produced by catalyzing the substrate acetylthiocholine (ATCl) with enzymes and it quenched the anodic ECL signal from c-PFBT NPs and simultaneously promoted the cathodic ECL signal from L-CdS QDs. When OPs was present, the activity of AChE was inhibited, the anodic signal would increase, and the cathodic signal would accordingly decrease. The integration of the bifunctional moderator H2O2 and dual-signal combined nanoprobe c-PFBT NPs@CdS QDs not only provides an attractive ECL platform for enzymatic sensing involving the generation or consumption of H2O2 but also paves a new pathway for other ratiometric ECL systems involving enzyme catalytic amplification for detecting antigens, antibodies, DNA, RNA, etc.

Iridium(III) complexes have been developed as eminent electrochemiluminescence (ECL) luminophores, but their current applications are only limited to anodic ECL emission because of weak cathodic ECL emission. This work explored poly(styrene-co-maleicanhydride) (PSMA) as functional reagent to modulate iridium(III) complexes to simultaneously emit bipolar ECL signals. The prepared iridium(III) nanorods (Ir NRs) were detected strong bipolar ECL emissions at +0.9 V and -2.0 V with N,N-diisopropylethylenediamine (DPEA) and persulfate (S

The limitation of the selection of dual-emitting luminophor and dual-function moderator makes the construction of single-luminophor-based electrochemiluminescence (ECL) ratio strategy extremely challenging. This work developed black phosphorus nanosheet loaded with CdTe quantum dots (BP-CdTe QDs) as dual-emitting luminophor, and TiO

In general, suitable double luminophores and their coreactants are necessary for constructing electrochemiluminescence (ECL) ratio strategy. However, the complexity of matching double luminophores and the stability and repeatability problem suffered by introducing exogenous coreactant would greatly limit the application of ratio detection. An original single-luminophore-based ECL ratio sensing was developed excluding any exogenous coreactants in this work. The poly [9,9-bis(3'-(N,N-dimethylamino)propyl)- 2,7-fluorene]-alt-2,7-(9,9-dioctylfluorene)] nanoparticles (PFN NPs) were explored to emit two anodic ECL signals. One centered at + 1.25 V (ECL-1) with the scanning potential of 0 ~ + 1.25 V and the other at + 1.95 V (ECL-2) with the scanning potential of 0 ~ + 1.95 V. ECL-1 showed a very strong emission without any exogenous coreactant. Importantly, hydrogen peroxide (H

The reported donor donor-acceptor ("DD-A") fluorescence resonance energy transfer (FRET) was typically achieved through random collisions and interactions of DNA molecules in the bulk solution, which has inevitable defects, including weak biological stability, slow reaction kinetics, and low hybridization efficiency. In order to overcome these deficiencies, this work developed a quadrivalent cruciform DNA nanostructure (qCDN)-mediated cascaded catalyzed hairpin assembly (CHA) amplifier for the fluorescence detection of amyloid β oligomer species (AβOs). First, four H1 and four H2 hairpins were assembled on one qCDN to obtain qCDNH1 and qCDNH2, respectively. In the presence of AβOs, strand C was released from the P1-C hybrid hairpin and then alternately opened qCDNH1 and qCDNH2 to trigger the qCDN-mediated CHA. As a result, double donors in H1 and one acceptor in H2 were mutually closed, and the porous DNA nanonet with a high loading of "DD-A" FRET binary probes was formed. The FRET efficiency was approximately 78%, and the initial reaction rate was 25-fold faster than the conventional CHA. The detection limit of AβOs was as low as 0.69 pM. The combination of the "DD-A" FRET binary probes and qCDN-mediated cascaded amplifier exhibited great promise for detecting biomarkers with trace levels.

The poor solubility and limited ECL emission efficiency of iridium (Ir) complexes in aqueous restricted their application in ECL field. This work prepared water-soluble Ir nanorods (Ir NRs) via carboxyl-functionalizing tris (2-phenylpyridine) iridium(Ⅲ) (Ir(ppy)3) using poly(styrene-co-maleicanhydride) (PSMA) and further developed a highly sensitive dual-signal nanoprobe with Ir NRs as anodic emitter and CdS quantum dots (QDs) as cathodic emitter. Ir NRs@CdS QDs served as the matrix to immobilize enzymes to construct an ECL ratio biosensor for detecting organophosphorus pesticides (OPs). The dual-functional H2O2 produced by enzymatic reaction had an opposite effect on two ECL signals, namely enhanced the cathodic signal and quenched the anodic signal. With the OPs, the activity of enzyme was inhibited and the generation of H2O2 was prevented, thus the opposite changes of two ECL signals were detected. The detection of ethyl paraoxon (EP) as target OPs was achieved with a linear range from 5.0 × 10−12 to 5.0 × 10−8 M and detection limit was 1.67 × 10−12 M. The excellent solubility and high ECL efficiency of Ir NRs in aqueous greatly expanded the application of Ir(Ⅲ) complexes. The opposite effect of H2O2 on two emissions of Ir NRs@CdS QDs provided a novel ratio ECL platform for bioanalysis.

A strong hydroxide (OH

Two new energetic complexes, Co(TO)2(DNBA)2(H2O)2 (1) and Cu(TZA)(DNBA) (2) (TO = 1,2,4-triazole-5-one, HTZA = tetrazole-1-acetic acid, HDNBA = 3,5-dinitrobenzoic acid), were synthesized using a microwave method with high yields. Single crystal X-ray diffraction revealed that 1 possess a 3D supramolecular structure with mononuclear units and 2 has a 2D supramolecular architecture with 1D chains. Thermoanalysis demonstrated that the two complexes have good thermostability, up to 238 °C for 1 and 270 °C for 2. The non-isothermal kinetics for exothermic processes of the complexes were studied using Kissinger's and Ozawa's methods. The calculated detonation properties and sensitivity tests showed that both complexes could be used as potential explosives. In addition, the two complexes were explored as combustion promoters to accelerate the thermal decomposition of RDX (1,3,5-trinitro-1,3,5-triazinane) using differential scanning calorimetry.

In a common electrochemiluminescence (ECL) detection, both introducing exogenous species and applying dissolved oxygen (O2) as coreactant may lead to a poor stability and reproducibility of the ECL system, and labeling the quencher for achieving signal changes is not only expensive but also inefficient. Since it was found that the carboxyl-functionalized poly[(9,9-dioctylfluorene-2,7-diyl)-co-(1,4-benzo-{2,1′-3}-thiadiazole)] (C-PFBT) dots exhibited a strong ECL emission without exogenous coreactant and dissolved oxygen, and H2O2 could quench the ECL emission of C-PFBT dots highly effectively, a coreactant-free ECL biosensor with in situ generation of quencher was proposed for ultrasensitively determining microRNA (miRNA). With the combination of a target cycle and hybridization chain reaction (HCR), large amounts of glucose oxidase (GOD) were introduced to generate the quencher H2O2 in situ, thereby achieving an ECL detection of miRNA with a low detection limit of 33 aM. The biosensor exhibited a potential practicability for detecting miRNA in specific cell lysates. The combination of C-PFBT dots and quencher H2O2 would arouse a significant interest in an ECL analysis, especially in coreactant-free ECL enzyme based-sensing field.

In the electrochemiluminescence (ECL) assays, it is difficult to find potential-resolved ECL luminators excluding the mutual interference of their coreactants and the resonance energy transfer between them, which makes it a great challenge to achieve a potential resolution-based multiple immunoassay. A novel potential-resolved ECL strategy based on N-(aminobutyl)-N-(ethylisoluminol) (ABEI) and graphiticphase carbon nitride nanosheet (g-C3N4) was constructed for synchronously multiplexed immunoassay of brain natriuretic peptide (BNP) and cardiac troponin I (cTnI). Au nanoparticles were modified onto the electrode surface to capture the anti-cTnI1 and anti-BNP1. The antigens of cTnI and BNP, secondary antibody composites anti-cTnI2-AuNPs@ABEI and anti-BNP2-AuNPs@g-C3N4 were stepwise incubated onto the electrode surface. With the increase in the concentration of BNP and cTnI, the ECL signals at +0.7 V from ABEI and −1.5 V from g-C3N4 were simultaneously increased, thus achieving the synchronous immunoassay of BNP and cTnI. The detection limits of cTnI and BNP were 3.2 pg/mL and 3.8 pg/mL, respectively. The integration of ABEI/O2 and g-C3N4/S2O82− system avoided the defects of the currently multiplexed immunoassay, thus providing an attractive ECL platform for synchronous determination of multiple biomarkers at the same sensitive interface.

A strong hydroxide (OH−)-dependent ECL emission of carboxyl functionalized-poly (9,9-di-n-octylfluorenyl-2,7-diyl) polymer dots (PFO Pdots) was observed at +1.25 V, which is significantly stronger than the emission at +1.95 V reported in previous work. Moreover, hydrogen peroxide (H2O2) can efficiently quench OH−-dependent ECL emission of PFO Pdots. Based on this discovery, a signal “off-on” ECL biosensing platform for microRNA-155 (miRNA-155) was developed. Firstly, PFO Pdots were modified onto the electrode to capture DNA duplex track-locker. In the presence of H2O2 in the test solution, the ECL signal of PFO Pdots was quenched to obtain a signal-off state. Subsequently, the DNA walker produced through the target miRNA-155-triggered catalytic hairpin assembly (CHA) walked along the DNA duplex track-locker to output amounts of G-rich short chain, forming a hemin/G-quadruplex. With the consumption of H2O2 by hemin/G-quadruplex, the ECL signal would be restored to a signal-on state, thus achieving an ultrasensitive detection of miRNA-155. The detection limit was low as 12.2 aM. Furthermore, our proposed biosensor demonstrated a tremendous selectivity and admirable stability, and exhibited a satisfactory performance for determinating intracellular miRNA-155. The integration of excellent ECL performance of PFO Pdots without any exogenous species or dissolved O2 as co-reactant and a highly efficient quenching effect of H2O2 on such an ECL emission will provide an attractive ECL platform for bioanalysis and clinical diagnosis.

The strenuous fluctuation in global asset price in recent years has had a profound impact on the economic and social development of every country. An empirical analysis indicates that asset prices (the stock price index and real estate prices) are important endogenous variables affecting the interest rate reaction function of central bank monetary policy. With expected inflation as a given, each one percentage point rise in output gap will cause a 0.79 percentage point reduction in interest rates by the central bank and each one percentage point rise in real estate price will result in a 2.2 percentage point rise in interest rates. The stock price index does have an influence on the trends in monetary policy, but it is less salient than the impact of housing prices. We also show that monetary policy that employs asset price as an endogenous variable increases the central bank’s control in seeking to attain its objectives. Therefore we suggest that the central bank should make asset price fluctuation an endogenous variable and incorporate it into its forward-looking interest rate rule, in order to facilitate the healthy development of China’s markets for real estate, stocks and derivatives, energy and bulk commodities and maintain rapid, smooth, sustainable and harmonious economic development.

China has been a member of the World Trade Organization (WTO), and now more attention will be diverted to the capital market of China. In this article, we discuss the degree of association of Chinese commodity futures markets with the international futures markets, with which we take the commodity exchange of Dalian and the Chicago Board of Trade (CBOT) as examples. Based on the collected data, we establish the cointegration relation between the close price and open interest in food commodity futures markets. Furthermore, we find that there is a cointegration relation between the soybean futures price of Dalian and the soybean spot price of Heilongjiang in China. These findings have demonstrated the principle of convergence between the futures price and the spot price based on econometric methodology.

The problem of compiling the rectangle UV input-output tables under the hypothesis of product technology has beset people long time. In this article, we introduced the theory of Moore-Penrose inverse matrix into the input-output analysis, derived the adjusting formulas in the situation of rectangle UV input-output table and resolved the problem of compiling the rectangle UV input-output tables under the hypothesis of product technology. We put the same position completely between the hypothesis of product technology and the hypothesis of sector technology in the theory of input-output analysis. Finally, we take an example as an illustration of this method.