Search

At present, the grain subsidies in China are mainly in forms of technical subsidies, like subsidies for superior seed varieties and general subsidies for agricultural production supplies and grain purchase prices. However, the purpose of the paper focuses on whether these subsidy policies can cause good effects and encourage farmers to grow grains and what impact these subsidy policies have on farmers' income. The paper takes a specific area as a research object and sorts the data using the statistical analysis put in the paper. Considering the current agricultural production conditions, the paper studies the content and structure of grain subsidy policy and the changes in grain growing acreage, farmers' income, and agricultural power machinery under the implementation of grain subsidy policy. In the end, the paper makes a research into the effect of implementing the grain subsidy policy, uses the statistical analysis to empirically analyze the impact the grain subsidy policy has on grain growing acreage, and draws a conclusion. [ABSTRACT FROM AUTHOR]

In this paper, we present measurements and analysis of propagation channels in vehicle-to-infrastructure (V2I) scenarios, which are the basis of designing vehicular communication systems. Firstly, we propose a deterministic geometry-based method to classify V2I links into three types, i.e., line-of-sight beneath (LOS-B), non-LOS (NLOS), and line-of-sight above (LOS-A), based on the environmental features, where roadside row of trees constitute the main obstacles. Secondly, for each link, we investigate the large-scale fading effect on V2I channels, including the path loss exponent and shadowing components. Subsequently, we validate the empirical path loss model using extensive measurements and two classical channel models. The results show a good fit with a near-zero mean and tolerable standard deviation of the estimation error. Finally, we analyze the small-scale fading effects, including fading depth and distance-dependent Ricean K-Factor, which are very important for accurately predicting the required fading margin and link budget. Through the analysis and simulations, this work provides a reference of the V2I channel characteristics for the test, design, and performance analysis of V2I communication systems. [ABSTRACT FROM AUTHOR]

An integrated structural health monitoring (SHM) system for highway bridges is presented. The system is based on a customized wireless sensor network platform with a flexible design that provides a variety of sensors typical in SHM. These sensors include accelerometers, strain gauges, and temperature sensors with ultra-low power consumption. An S-Mote node, an acceleration sensor board, and a strain sensor board are developed to satisfy the requirements of bridge structural monitoring. Communication software components are integrated within TinyOS operating system to provide a flexible software platform whereas the data processing software performs analysis of acceleration, dynamic displacement, and dynamic strain data. The prototype system comprises a nearly linear multi-hop topology and is deployed on an in-service highway bridge. Data acquired from the system are used to examine network performance and to help evaluate the state of the bridge. Experimental results show that the system enables continuous or regular interval monitoring for in-service highway bridges. [ABSTRACT FROM AUTHOR]

Abstract: A new method for the determination of roxithromycin based on the fluorescence quenching of 3-mercaptopropionic acid-capped CdTe quantum dots (MPA-CdTe QDs) was developed. In ethanol medium, the fluorescence of CdTe quantum dots at 552nm was quenched in the presence of roxithromycin. Based on this a simple, sensitive, and selective method for rapid determination of roxithromycin was described. Reaction time, interfering substances on the fluorescence quenching, and mechanism of the interaction of CdTe QDs with roxithromycin were investigated. After optimization, the proposed method allows the determination of roxithromycin over the range 25.0–350.0μgml−1. The detection limit is 4.6μgml−1. The proposed method was successfully applied to commercial capsules and tablets with satisfactory results. The recovery of the method was in the range of 96.8–102.5%. [Copyright &y& Elsevier]

Abstract: A new and simple method for fabricating controllable insulated nanometer-sized platinum electrodes is presented. Electrochemical etching of platinum wire is employed, and then a repeated process of cycle voltammetric deposition of electrophoretic paint and heat curing for shrink film follows which effectively controls the size of the nanoelectrodes, which is different from previous DC electrolysis deposition. This technique allows complete insulation of the whole body of the etched platinum wire, except for the very tip with the shrink film during heat curing of the film, leaving an electrochemical active area with effective diameters of nanometers. The process overcomes the pinhole formation resulting from the electrophoretic paint deposition process. The size of the platinum electrodes and the thickness of the deposed paint for insulation can be properly controlled and reproduced. The fabricated electrodes show ideal steady-state voltammetric behaviors from which the effective areas of the nanoelectrodes are measured. The effective radius of the prepared nanoelectrodes ranges from 3.1nm to hundreds of nanometers. [Copyright &y& Elsevier]

Benzoyl peroxide (BP) was determined by differential pulse voltammetry (DPV) using a glassy carbon electrode in a dichloromethane‐acetic acid (1.5×10 -2 mol l -1 ) solution and tetrabutyl ammonium perchlorate (0.01 mol l -1 ) as the supporting electrolyte. The peak potential was -0.045 V (vs. Ag/AgCl). There was a good linear relationship between the peak current and the benzoyl peroxide concentration in the range of 2.5×10 -6 –1.0×10 -4 mol l -1 . The detection limit of the method was 2.5×10 -7 mol l -1 . The recovery was 94.8–106.0%. The samples of wheat flour and the pharmaceutical preparations for the treatment of acne vulgaris were directly detected with desired results. The reaction mechanism of benzoyl peroxide on the electrode was also discussed, which was two electrons and two protons irreversible reaction. [ABSTRACT FROM AUTHOR]

Benorilate was determined by the differential pulse voltammetry (DPV) using a carbon paste electrode in 1.25 x 10-3 mol . l-1 KH2PO4 and Na2HPO4 buffer solution (pH = 6.88, 25°C). The anodic peak potential was +1.020V (versus saturated calomel electrode (SCE)). A good linear relationship was realized between the anodic peak currents and benorilate concentrations in the range of 2.0 x 10-7 to 4.5 x 10-4mol . l-1 with the detection limit of 5.0 x 10-8mol . l-1. The recovery was 94.3 to 104.6% with the relative standard deviation of 3.5% (n = 9). The pharmaceutical preparations, benorilate tablets samples, were determined with desirable results. [ABSTRACT FROM AUTHOR]

A method for determination of paracetamol is established by the differential pulse voltammetry (DPV) using a pumice mixed carbon paste electrode with the pumice weight percent of 6% (m/m) in 0.1 mol1[SUP-1] H[SUB2]SO[SUB4]. The anodic peak potential is ca. 0.640V (vs. SCE). There is a good linear relationship between the peak current and paracetamol concentration in the range of 6.0 × 10[SUP-8] -1.0 × 10-[SUP-6]mol1[SUP-1], and 2.0 × 10[SUP-6] -9.8 × 10[SUP-5] mo1l[SUP-1] with the detection limit of 2.0 × 10[SUP-8] mol 1[SUP-1]. Compared with the carbon paste electrode, the detection limit of this method decreases two orders of magnitude. This method is rapid, simple, accurate and highly sensitive. Satisfactory results for determination of paracetamol in pharmaceutical preparations and urine are obtained. [ABSTRACT FROM AUTHOR]

With the development of credit businesses, privacy data leakage and data accuracy in loan transactions among different banks tend to be worrisome issues hindering the prosperity of the industry. To address the problem, we propose a blockchain-based cross-bank over-loan prevention (CBOL-ring) mechanism, which ensures that, on the one hand, the plaintext of loan transactions cannot be access to neither participants on the nodes except the bank that handles loan/repayment requests, so as to prevent the borrower from loaning without revealing their privacy data; on the other hand, the other participants are able to prove the effectiveness of the plaintexts through checking the ciphertexts on the blockchain. In addition, we propose a blockchain-based cross-bank over-loan prevention mechanism with low communication volume (CBOL-bullet), which reduces the size of the range proof generated by the BBCBOLP mechanism, thereby reducing the size of the communication volume and saving resources during the data transmission process. Finally, we analyze the security and performance of the two mechanisms, and compare the communication volume of the two mechanisms. [ABSTRACT FROM AUTHOR]

CsPbX3 perovskite nanocrystal (NC) is considered as an excellent optical material and is widely applied in optoelectronics. However, its poor water stability impedes its study in enzyme‐like activity, and further inhibits its application in biomimetic cascade catalysis. Herein, for the first time, the oxidase‐like and ascorbate oxidase‐like activities of an amphiphilic polymer capped CsPbX3 are demonstrated, and its catalytic mechanism is further explored. Furthermore, an all‐nanozyme cascade system (multifunctional CsPbBr3@Zr‐metal organic framework (Zr‐MOF) and Prussian blue as oxidase‐like and peroxidase‐like nanozyme) is constructed with a portable paper‐based device for realizing the dual‐mode (ratiometric fluorescence and colorimetric) detection of ascorbic acid in a point‐of‐care (POC) fashion. This is the first report on the utilization of all‐inorganic CsPbX3 perovskite NC in biomimetic cascade catalysis, which opens a new avenue for POC clinical disease diagnosis. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) show excellent catalytic activity and have been widely applied in diagnosis of diseases and tumors. However, current assay methods usually involve cumbersome configurations and complicated procedures, which inhibit their practical applications. Hence, a Cu–Ni MOF/carbon printed electrode (CPE)-based integrated electrochemical immunosensor was constructed for highly sensitive and efficient determination of carcinoembryonic antigen (CEA). First, highly conductive carbon ink was screen-printed onto a polyethylene terephthalate substrate to manufacture a CPE. Afterward, an aminated Cu-Ni MOF was prepared by a typical solvothermal strategy and modified on the CPE. Owing to its excellent peroxidase activity, the Cu–Ni MOF can catalytically oxidize hydroquinone using hydrogen peroxide, which greatly amplifies the peak current signal. Then the formation of an immune complex inhibited the catalytic activity of the MOF, thus enabling the quantitative determination of CEA content with a wide linear range of 0.5 pg mL−1–500 ng mL−1 and a low detection limit of 0.16 pg mL−1. Furthermore, the Cu–Ni MOF/CPE-based integrated portable electrochemical immunosensor also showed satisfactory performance in the detection of CEA in clinical serum samples with excellent accuracy, showing great potential for application in point-of-care disease diagnosis. [ABSTRACT FROM AUTHOR]

Pyroptosis is widely involved in many diseases, including periodontitis. Nonetheless, the functions of pyroptosis-related genes (PRGs) in periodontitis are still not fully elucidated. Therefore, we aimed to investigate the role of PRGs in periodontitis. Three datasets (GSE10334, GSE16134, and GSE173078) from the Gene Expression Omnibus (GEO) were selected to analyze the differences in expression values of the PRGs between nonperiodontitis and periodontitis tissue samples using difference analysis. Following this, five hub PRGs (charged multivesicular body protein 2B, granzyme B, Z-DNA-binding protein 1, interleukin-1β, and interferon regulatory factor 1) predicting periodontitis susceptibility were screened by establishing a random forest model, and a predictive nomogram model was constructed on the basis of these genes. Decision curve analysis suggested that the PRG-based predictive nomogram model could provide clinical benefits to patients. Three distinct PRG patterns (cluster A, cluster B, and cluster C) in the periodontitis samples were revealed according to the 48 significant PRGs, and the difference in the immune cell infiltration among the three patterns was explored. We observed that all infiltrating immune cells, except type 2 T helper cells, differ significantly among the three patterns. To quantify the PRG patterns, the PRG score was calculated by principal component analysis. According to the results, cluster B had the highest PRG score, followed by cluster A and cluster C. In conclusion, PRGs significantly contribute to the development of periodontitis. Our study of PRG patterns might open up a new avenue to guide individualized treatment plans for patients with periodontitis. [ABSTRACT FROM AUTHOR]

Microcantilever-based immunosensor is a next-generation electromechanical technique with broad application in biological detection. In this paper, we reported a microcantilever-based immunosensor that quantitatively detect the carbofuran, by using monoclonal antibodies to carbofuran as the receptor molecules. The surface of gold-coated microcantilever was chemically modified by the crosslinking of l -cysteine ( l -cys)/glutaraldehyde (GA). The monoclonal antibodies to carbofuran were then immobilized on the side of the microcantilever to fabricate the immunosensor, the mechanical bending induced by antigen-antibody specific binding under an experimental environment. Under the optimized conditions, immunosensor detected carbofuran showed a good linear relationship over the range from 1.0 × 10 −7 to 1.0 × 10 −3 g/L (R = 0.998), with a detection limit of 0.1 ng/mL. Moreover, the proposed immunosensor exhibited high sensitivity, specificity and good stability and can be successfully applied in the carbofuran determination in soil and vegetable samples with satisfactory results. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-C3N4) has been widely used in fields related to energy and materials science. However, nanostructured g-C3N4 photocatalysts synthesized by traditional thermal polycondensation methods have the disadvantage of small specific surface areas and wide band gaps; these limit the catalytic activity and application range of g-C3N4. Based on the unique nanostructure of g-C3N4, it is a feasible method to modify g-C3N4 with metals to design novel metal-semiconductor composites. Metals alter the photochemical properties of g-C3N4, in particular, narrow the band gap and expand photoabsorption into the visible range, which improves the photocatalytic performance. This review covers recent progress in metal/g-C3N4 nanocomposites for photocatalysts, organic systems, biosensors, and so on. The aim is to summarize the synthetic methods, nanostructures, and applications of metal/g-C3N4 nanocomposite materials, as well as discuss future research directions in these areas. [ABSTRACT FROM AUTHOR]

Background: As one of the fundamental problems in bioinformatics, the double digest problem (DDP) focuses on reordering genetic fragments in a proper sequence. Although many algorithms for dealing with the DDP problem were proposed during the past decades, it is believed that solving DDP is still very time-consuming work due to the strongly NP-completeness of DDP. However, none of these algorithms consider the privacy issue of the DDP data that contains critical business interests and is collected with days or even months of gel-electrophoresis experiments. Thus, the DDP data owners are reluctant to deploy the task of solving DDP over cloud. Results: Our main motivation in this paper is to design a secure outsourcing computation framework for solving the DDP problem. We at first propose a privacy-preserving outsourcing framework for handling the DDP problem by using a cloud server; Then, to enable the cloud server to solve the DDP instances over ciphertexts, an order-preserving homomorphic index scheme (OPHI) is tailored from an order-preserving encryption scheme published at CCS 2012; And finally, our previous work on solving DDP problem, a quantum inspired genetic algorithm (QIGA), is merged into our outsourcing framework, with the supporting of the proposed OPHI scheme. Moreover, after the execution of QIGA at the cloud server side, the optimal solution, i.e. two mapping sequences, would be transferred publicly to the data owner. Security analysis shows that from these sequences, none can learn any information about the original DDP data. Performance analysis shows that the communication cost and the computational workload for both the client side and the server side are reasonable. In particular, our experiments show that PP-DDP can find optional solutions with a high success rate towards typical test DDP instances and random DDP instances, and PP-DDP takes less running time than DDmap, SK05 and GM12, while keeping the privacy of the original DDP data. Conclusion: The proposed outsourcing framework, PP-DDP, is secure and effective for solving the DDP problem. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks/titanium dioxide (UiO-66-NH2/TiO2) nanocomposites have been prepared by a simple hydrothermal reaction and they exhibit excellent electrocatalytic activity for chlorogenic acid oxidation due to the synergic effect of UiO-66-NH2 and TiO2. Under the optimal conditions, the sensor can be employed in the quantification of chlorogenic acid in the ranges of 0.01–1.0 μmol L−1 and 1.0–15 μmol L−1 with an ultralow detection limit of 7 nmol L−1 (S/N = 3). Moreover, UiO-66-NH2/TiO2 nanocomposites demonstrate significant stability in acidic buffer solution and maintain their electrocatalytic activities at least up to 90 cycles. The potential utility was validated by the analysis of coffee and tea samples and good recoveries were obtained from different spiked values. The UiO-66-NH2/TiO2 based sensor with highly sensitive, selective and stable consecutive monitoring of chlorogenic acid is a promising candidate for the construction of highly active electrocatalyst in electrochemical biosensors. [ABSTRACT FROM AUTHOR]

[Display omitted] • FMIPs were prepared by selecting PFEA as a functional monomer. • FMIPs were employed for the functionalization of CH 3 NH 3 PbI 3 @CNDs. • FMIPs endowed perovskite with good selectivity, stability, and photoelectric property. • A novel cholesterol PEC sensor was developed based on FMIPs@CH 3 NH 3 PbI 3 @CNDs. • The new sensor has been successfully applied to cholesterol detection in human serum. Herein, a novel ultrasensitive cholesterol photoelectrochemical (PEC) sensor was designed based on fluorinated molecularly imprinted polymers (FMIPs) functionalized CH 3 NH 3 PbI 3 @carbon nanodots (CH 3 NH 3 PbI 3 @CNDs) platform. 2-(Perfluorooctyl) ethyl acrylate (PFEA), a functional monomer, was chosen not only to endow CH 3 NH 3 PbI 3 good selectivity but also improve its aqueous stability because of the fluorine containing long hydrophobic chain. Furthermore, the FMIPs can inhibit the recombination of electron holes and prolonged the carrier life time, and dramatically enhance the charge transfer efficiency by the reduction of defect density through the polymer passivation of grain boundaries of perovskite. The morphology, the enhanced hydrophobicity and photoelectric properties of FMIPs@CH 3 NH 3 PbI 3 @CNDs interface was characterized by transmission electron microscopy, Fourier transform infrared spectrum, scanning electron microscope, contact angle, photoluminescence spectrum and intensity modulated photovoltage spectrum, respectively. Under the optimized conditions, the linear range of the designed PEC sensor for cholesterol detection was 1.0 × 10−13–1.0 × 10−9 mol/L, and the detection limit was down to 8.9 × 10−14 mol/L. The new PEC sensor exhibited specific selectivity, good stability and hypersensitivity, and was successfully applied to cholesterol detection in human serum samples. This work extended the development of the MIPs based sensor and the high-performance perovskite. [ABSTRACT FROM AUTHOR]

In this research, dual-strategy biosensing of glucose was proposed based on multifunctional CuWO4 nanoparticles (CuWO4 NPs), which were prepared for the application of electrochemical and colorimetric sensing of glucose. CuWO4 NPs show large specific surface area and good conductivity as well as excellent peroxidase-like activity. A sensitive and selective electrochemical glucose biosensor was fabricated with the immobilization of glucose oxidase (GOx) on a CuWO4 NP modified electrode for enhancing the direct electron transfer behavior. A wide linear range of 0.005–1.8 mM with a low detection limit of 1.5 μM and a high sensitivity of 28.02 mA M−1 cm−2 were achieved by using the electrochemical biosensor. Meanwhile, a colorimetric and visual glucose biosensor was constructed based on the GOx/CuWO4 cascade nanozyme, which shows a linear range of 0.05–1.0 mM with excellent selectivity. CuWO4 NPs as a promising matrix open up a dual-strategy biosensor for sensitive and selective detection of glucose. [ABSTRACT FROM AUTHOR]

It's a key problem to recognize the kinds of sediments in the ocean bottom during an acoustic survey or seismic exploration. In this paper, an ultrasonic rock physics experiment was introduced in the flume, which simulated different sedimentary types of ocean bottom, such as stone, fine sand, coarse sand, silt and cement. After processing the simulated acoustic data, some physical attributes, which are sensitive to different types of sediment, was found. In which, the weighted average frequency attribute can distinguish the coarse sand, silt and stone substrate if combined with sweetness attribute. The instantaneous quality factor (Q) attribute highlights the cement restrained with the weighted average frequency attribute. Through analyzing the relationships between porosity, density and these sensitive acoustic attributes, the types of sediment in the flume can be deduced and inversed by artificial neural network method. [ABSTRACT FROM AUTHOR]

Possessing prominent customization in structural design as well as unique physicochemical properties, covalent organic frameworks (COFs) show great potential in the biosensing field. In this study, we prepared a novel COF-based electrochemical enzymatic composite (denoted as Fe3O4@COF@HRP), where spherical magnetic COF was functionalized with horseradish peroxidase (HRP). The resultant composite was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. Thereinto, the Fe3O4 nanoparticles with remarkable conductivity could accelerate the charge transfer, while HRP with good catalytic activity could enhance the sensitivity of the as-prepared biosensor. With such a design, the Fe3O4@COF@HRP-based biosensor exhibits excellent analytical properties for the determination of hydroquinone. The extended linear detection range was 0.5–300 μmol L−1, and the limit of detection was down to 0.12 μmol L−1 (S/N = 3). Furthermore, the electrochemical enzymatic biosensor was used to detect low-abundance hydroquinone in environmental water samples with a satisfactory consequence, suggesting great promise in sensing applications. [ABSTRACT FROM AUTHOR]

The development of flexible substrate materials and nanomaterials with high electrochemical performance is of great significance for constructing efficient wearable electrochemical sensors for real-time health monitoring. Herein, a wearable electrochemical sweat sensor based on a Ni–Co MOF nanosheet coated Au/polydimethylsiloxane (PDMS) film was prepared for continuous monitoring of the glucose level in sweat with high sensitivity. First, a stretchable Au/PDMS film based three-electrode system was prepared by chemical deposition of a gold layer on the hydrophilic treated PDMS. Then, Ni–Co MOF nanosheets with high electrocatalytic activity were synthesized by a facile solvothermal method and modified on the Au/PDMS electrode. The electrocatalytic activity of the Ni–Co MOF nanosheets synthesized under different Ni : Co ratios was investigated. The Ni–Co MOF/Au/PDMS (NCAP) film electrode showed excellent electrochemical performance for glucose detection with a wide linear range of 20 μM to 790 μM and a high sensitivity of 205.1 μA mM−1 cm−2. In addition, the flexible sensor shows high stability and a good electrochemical response to glucose when stretched and bent to different levels. Moreover, it maintained long-term stability and high selectivity for glucose monitoring. Lastly, a sweat-absorbent cloth was used to cover the working area of the sensor and was fixed with a needle and thread to form a wearable sweat glucose sensor. The sensor can be attached to the skin for stable, accurate and continuous monitoring of glucose levels in human sweat for one day. This work validates the potential of our high-performance wearable sensor for out-of-clinic health monitoring. [ABSTRACT FROM AUTHOR]

Abstract: An electrochemical method has been successfully demonstrated for sensitive determination of Metronidazole (MTZ) with graphene (Gr)-room temperature ionic liquid (IL) of 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6) composite modified glassy carbon electrode (GCE). The cyclic voltammetric results indicate that Gr-IL/GCE can remarkably enhance electrocatalytic activity towards the reduction of MTZ in neutral solutions. MTZ produce a cathodic peak at about −0.69V at this electrode. The electrochemical parameters of MTZ in the composite film were carefully calculated with the results of the charge transfer coefficient (α) as 0.625 and the number of electron transferred (n) as 4. The electrocatalytic behavior was further exploited as a sensitive detection scheme for the MTZ determination by differential-pulse voltammetry (DPV). Under optimized conditions, the concentration range and detection limit were 1.0×10−7–2.5×10−5 molL−1 and 4.7×10−8 molL−1 (S/N =3), respectively for MTZ. The method was successfully applied assay of the drug in the pharmaceutical dosage forms. [Copyright &y& Elsevier]

Abstract: This study was carried out to develop the application of modified carbon fiber electrode in environmental detection, by which chromium (III) ion in water could be electrochemically detected. The modified carbon fiber electrode manifested a linear response within the range of 1.9×10−6–4.6×10−4 molL−1 (R =0.9939) and the detection limit was 7.9×10−7 molL−1. The effect factors were studied to reveal the optimal conditions in the detection of chromium (III) in water, such as pH of total ionic strength adjustment buffer, the concentration of calix[4]resorcinarene, sweep cycles, and so on. The modified carbon fiber electrode, the diameter of which was about 7μm, was characterized by field emission scanning electron microscopy and electrochemical impedance spectroscopy. Also, the proper mechanism was discussed. The identification of chromium (III) was mainly attributed to the cavity of the calix[4]resorcinarene that the chromium (III) ion could enter into the inner of calix[4]resorcinarene because of the particular structure of calix[4]resorcinarene. [Copyright &y& Elsevier]

Abstract: With water droplets as sacrificed templates at a particular humidity, micro-porous solid thin films were successfully fabricated by self-assembly using an amphiphilic block polymer, polystyrene-b-polyacrylic acid (PS-b-PAA). Interface interactions between the micro-porous thin film and a cationic surfactant, cetyltrimethylammonium bromide (CTAB), are investigated by in-situ AFM in aqueous solutions. An interesting phenomenon was observed in water and CTAB solution, which the dimensions of the micropores are remarkably larger than the dimensions of those in air. The solid thin films exhibit different surface morphologies in response to stimulus by different concentrations of CTAB. These observations were explained by positing that the PAA chains in the micropores stretch and contract with interface interactions between PAA and CTAB. A promising electrochemical application of this film is suggested. This study is aimed at strategies for the functionalization of stimulus-responsive micro-porous solid thin films with tunable surface morphologies, and exploring new smart materials. [Copyright &y& Elsevier]

Abstract: A new petentiometric method to determine peroxide hydrogen and glucose had been studied. This method had been applied on the petentiometric determination of peroxide hydrogen and glucose in the total ionic strength adjustment buffer (TISAB) (pH 7.5) solution with the glassy electrode modified by the calix[4]arene. The glassy carbon electrode covered with the calix[4]arene depended on the H2O2 concentration in the range of log[H2O2] from −3.3 to −1.2 in the solution of TISAB (pH 7.5) with nearly Nernstian slope of about 65.6±3mV and the detection limit of peroxide hydrogen was 4.0×10−5 molL−1. The glassy carbon electrode covered with the calix[4]arene depended on the glucose concentration in the range of log[glucose] from −3.6 to −2.8 in the solution of TISAB (pH 7.5) with nearly Nernstian slope of about 50.2±2mV and the detection limit of glucose was 2.0×10−5 molL−1. The electrode had the good selectivity, sensitivity, stability and repeatability. [Copyright &y& Elsevier]

Abstract: Sequential injection lab-on-valve (LOV) was first proposed for analyzing ultra-trace amounts of Pb using differential pulse anodic stripping voltammetry (DPASV) with a miniaturized electrochemical flow cell fabricated in the LOV unit. Deposition and stripping processes took place between the renewable mercury film carbon paste electrode and sample solution, the peak current was employed as the basis of quantification. The mercury film displayed a long-term stability and reproducibility for at least 50 cycles before next renewal, the properties of integrated miniature LOV unit not only enhanced the automation of the analysis procedure but also declined sample/reagent consumption. Potential factors that affect the present procedure were investigated in detail, i.e., deposition potential, deposition time, electrode renewable procedure and the volume of sample solution. The practical applicability of the present procedure was demonstrated by determination of Pb in environmental water samples. [Copyright &y& Elsevier]

A novel chemiluminescent immunosensor for carbohydrate antigen 19-9 (CA19-9) based on the immobilization of CA19-9 on the cross-linked chitosan membrane was developed. The different membranes were characterized by atomic force microscopy (AFM) and infrared spectrum, respectively. Based on a noncompetitive immunoassay format, this proposed chemiluminescent immunosensor enabled a low-cost, flexible and rapid determination for CA19-9 in combination with flow injection analysis (FIA). After an off-line incubation of the analyte CA19-9 with horseradish peroxidase (HRP)-labeled anti-CA19-9, the mixture was injected into the immunosensor, which led to the trapping of free HRP-labeled anti-CA19-9 by the immobilized antigen in the immunosensor. The trapped HRP-labeled antibody was detected by chemiluminescence due to its catalytic activity following the reaction of luminol and H2O2. Under optimal conditions, the decreased chemiluminescent signal of the immunosensor was proportional to the CA19-9 concentration in the range of 2.0–25 U/ml with a detection limit of 1.0 U/ml. The immunosensor showed an acceptable accuracy and good reproducibility. The results of 20 human serum samples detected by this method were in acceptable agreement with those obtained by immunoradiometric assay. The proposed immunosensor provided a new promising tool for practical clinical detection of the serum CA19-9 level. [Copyright &y& Elsevier]

The poor stability and aqueous-quenching of fluorescence of perovskite nanocrystals (NCs) hinder their application in bio-detection and bio-imaging. Herein, through the synergistic effects of polymer surface ligand and silica encapsulation, highly stable and enhanced aqueous fluorescent CsPbBr3-mPEG@SiO2 NCs were synthesized and used as a novel "on–off–on" fluorescent probe for highly sensitive and selective detection of mercury ions (Hg2+) and glutathione (GSH) in aqueous solutions. The effects of the methoxypolyethylene glycol amine (mPEG-NH2) ligand and silica encapsulation on the stability and aqueous fluorescence of the CsPbBr3 NCs were studied. It indicated that the aqueous fluorescence of perovskite NCs was increased by 2.59 times. The water stability was also greatly improved, with the NCs maintaining 73% of their original fluorescence after storage for 30 days in water. X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR) analyses further demonstrated that the NCs were successfully passivated by mPEG-NH2 and silica. The fluorescence of the CsPbBr3-mPEG@SiO2 nanocrystals was effectively quenched by Hg2+ which is attributed to the electron transfer process between NCs and Hg2+. Then, through the interaction between Hg2+ and GSH, the restoration of fluorescence for CsPbBr3-mPEG@SiO2 was realized. The "on–off–on" fluorescent probe can be used for the detection of Hg2+ and GSH with a low detection limit of 0.08 nM and 0.19 μM, respectively. It also shows a fast response time and high accuracy for practical sample detection. The simple and sensitive fluorescent probe of CsPbBr3-mPEG@SiO2 shows great potential in environmental and biological sensing. [ABSTRACT FROM AUTHOR]

Using two-dimensional (2D) nickel-based metal organic framework (Ni-MOF) nanosheets as a matrix, Eu3+ and Ag+ were incorporated to synthesize Ag/Eu@Ni-MOF with double luminescence centers of Eu3+ ion (615 nm) and organic ligand (524 nm). And a ratiometric luminescence sensor is constructed based on Ag/Eu@Ni-MOF for sensitive detection of biothiols in aqueous solutions. The dual-emissive fluorescence properties can be tuned by changing the amounts of Ag+ ions doping. The results of temperature and pH effects on the fluorescence of Ag/Eu@Ni-MOF indicates that the Ag/Eu@Ni-MOF is a temperature-sensitive material and the fluorescence of Ag/Eu@Ni-MOF can keep stable over a wide pH range. Due to the binding of -SH in cysteine (Cys) and glutathione (GSH) with Ag+, the ligand luminescence was significantly inhibited by weakening the Ag + influence on the energy transfer process in the MOFs. Therefore, ratiometric fluorescent sensing of biomolecular thiols was realized based on the dual-emission Ag/Eu@Ni-MOF. More importantly, the fluorescence color change can be observed with naked eyes to realize visual detection. The ratiometric fluorescent sensor exhibits high performance for Cys and GSH detection with a wide linear range of 5-250 µM and a relatively low detection limit of 0.20 µM and 0.17 µM, respectively. Furthermore, the biothiols content in human serum was determined with satisfactory results. It proves the Ni-MOF nanosheets can be used as a stable matrix for construction luminescent MOFs for the first time, and validate the great potential of Ag/Eu@Ni-MOF as a ratiometric fluorescent probe for point-of-care testing (POCT) in disease diagnosis. [ABSTRACT FROM AUTHOR]

A novel hedgehog-shaped bismuth sulfide (HS-Bi2S3) nanostructure was for the first time explored as an electrode material for biosensing. Using cetyltrimethyl ammonium bromide (CTAB)-trimellitic acid as a composite soft template, the HS-Bi2S3 nanostructure was synthesized by a hydrothermal route. Using glucose oxidase (GOx) as the model, the HS-Bi2S3 nanostructure was employed to immobilize GOx for the development of a sensitive electrochemical glucose biosensor. The characterization of HS-Bi2S3 and the biosensor was performed by scanning electron microscopy, X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy and cyclic voltammetry. The hedgehog-shaped nanostructure of Bi2S3 has a large specific surface area to trap a large number of enzyme molecules, and at the same time greatly enhances the direct-electron-transfer action of enzymes. The HS-Bi2S3-based biosensor shows a wide linear range of 0.005–1.7 mmol L−1 and a low detection limit of 1.6 μmol L−1 for glucose at −0.37 V, which presents much better assay performance in comparison with the glucose biosensor without HS-Bi2S3. The present electrochemical biosensor displays high selectivity, good repeatability and stability, which can be used to measure blood glucose in real serum samples. [ABSTRACT FROM AUTHOR]

A covalent organic framework (COF) is a promising type of porous material with customizable surface characteristics. Confining multiple catalytic units within a mesoporous COF can generate abundant active sites and improve the catalytic performance. In this work, a COF with both metalloporphyrin and a metal nanoparticle complex denoted as hemin/TAPB-DMTP-COF/AuNPs (TAPB: 1,3,5-tris(4-amino-phenyl)benzene, DMTP: 2,5-dimethoxyterephaldehyde, AuNPs: Au nanoparticles) has been successfully fabricated through a hierarchical encapsulation method. The as-synthesized composite was then employed to construct an electrochemical sensing platform for the efficient detection of bisphenol A (BPA). Under the optimal conditions, the hemin/TAPB-DMTP-COF/AuNP sensor presented a linear range of 0.01–3 μmol L−1 and a low detection limit of 3.5 nmol L−1. The satisfactory signal amplification is based on a triple-signaling amplification strategy due to the abundant Fe3+ sites of Fe-porphyrin, high conductivity of AuNPs and a large specific surface area of the TAPB-DMTP-COF. The proposed method was used to measure the content of BPA in different water samples with a satisfactory recovery from 95.5 to 104.0%, suggesting the great potential of the sensor in practical applications. [ABSTRACT FROM AUTHOR]

Multimicrogrid (MMG) systems play an increasingly important role in the smart grid. They come with various potential cyberattacks, which may cause power supply interruption or even human casualties. Therefore, decision-making for timely mitigation of cyberattack risks is highly desirable in the security protection of power systems. However, there is a lack of effective decentralized decision-making strategies that are able to deal with MMG scenarios through distributed consensus. To address this issue, a decentralized consensus decision-making (DCDM) approach is proposed in this article for the security of MMG systems. It achieves decentralized consensus without the need of a trusted authority or central server, making it distinct from existing consensus methods. Meanwhile, it guarantees the consistency and nonrepudiability of consensus results, which are stored on the blockchain in sequence. In each of the distributed agents, the approach consists of a fuzzy static Bayesian game model (FSB-GM) to determine the optimal security strategy and a hybrid consensus algorithm to achieve consensus. The FSB-GM considers the fuzzy preferences of different types of attackers and defenders. The hybrid consensus algorithm is implemented by the fusion improvement of two consensus mechanisms in the blockchain. The effectiveness of the presented approach is demonstrated through a case study on an MMG system. [ABSTRACT FROM AUTHOR]

Programmed death ligand 1 (PD-L1) of tumor-derived extracellular vesicles (T-EVs) is an important biomarker to predict immunotherapy response. The traditional bioassays of T-EVs PD-L1 are limited by the detection specificity because of the distribution of the signals by PD-L1 from nontumor-derived EVs, which leads to unsatisfactory predictive accuracy. In this work, we developed a simple and ultrasensitive method for the quantification of T-EVs PD-L1 by using the lipid bilayer magnetic interface as the isolation and enrichment carrier along with hybridization chain reaction (HCR) for signal amplification in a paper-based device. First, magnetic beads were covered by liposome bilayers and then anchored with the cholesterol modified epithelial cell adhesion molecule (EpCAM) aptamer to construct a fluid multivalent magnetic interface and realize the high-performance isolation of T-EVs. Moreover, the biosensor relied on the PD-L1 aptamer to initiate the HCR of EVs. Benefiting from the high isolation ability of the lipid bilayer magnetic interface and the high signal amplification ability of HCR, the dual-aptamer-based biosensor is capable of highly sensitive detection of T-EVs with a detection limit as low as 5.0 EVs·µL−1 in a paper-based device. Overall, the paper-based lipid bilayer magnetic interface biosensor not only can serve as an alternative tool for predicting the immunotherapy response but also displays great potential in point-of-care disease diagnosis. • A paper-based lipid bilayer magnetic affinity interface for detection of T-EVs PD-L1. • The lipid bilayer magnetic interface realizes the high-performance isolation of the T-EVs. • PD-L1 aptamer was used to initiate the HCR of EVs to amplify the signal. • The dual-aptamer-based biosensor realizes ultrasensitive detection of T-EVs. • The biosensor can detect T-EVs in cancer patient samples without purification. [ABSTRACT FROM AUTHOR]

Rapid and highly sensitive detection of tumor marker (TM) is critical for the early diagnosis and treatment of cancers. Herein, utilizing highly bright and water-stable CsPbBr 3 perovskite nanocrystals (NCs) capped with amphiphilic polymer ligand of octylamine-modified polyacrylic acid (OPA) and gold nanoparticles (AuNPs) as reporters, a lateral flow immunoassay (LFIA) strip is developed for fluorescence and colorimetric dual-mode detection of carcinoembryonic antigen (CEA). The prepared CsPbBr 3 NCs capped by an amphiphilic polymeric of OPA ligand showed high stability and bright fluorescence. Moreover, the AuNPs immunoprobes were captured with CEA antigen and quench the green fluorescence of CsPbBr 3 /OPA NCs on the T line due to the inner filter effect (IFE). Therefore, CEA could be quantitative analyzed by the dual-readout of fluorescence and colorimetric signal. The detection limits of CEA can reach as low as 0.023 ng/mL and 0.027 ng/mL for the fluorescence and colorimetric mode, respectively. Good specificity and reproducibility were also demonstrated for this method. Finally, the CsPbBr3/OPA NCs-based LFIA showed good accuracy in detection of CEA level from clinical serum samples. This work firstly enables the application of CsPbBr 3 perovskite NCs in a LFIA, displaying great potential in point-of-care clinical diagnosis. [Display omitted] • A dual read-out LFIA strip based on CsPbBr 3 /OPA NCs for rapid detection of CEA. • The work firstly enables the application of CsPbBr 3 perovskite NCs in a LFIA. • The CsPbBr 3 /OPA NCs showed high photoluminescence and good water stability. • With the aid of AuNPs, dual read-out competitive immunoassay analysis of CEA realized. • The LFIA strips showed high performance for CEA detection. [ABSTRACT FROM AUTHOR]

Facile fabrication of sponge-like bulk adsorbent with interpenetrated porous structure by anchoring β-FeOOH into the polyacrylamide gel network and its application in aqueous for the efficient removal of phosphate. • A β-FeOOH based sponge-like bulk material (FSP-f) was facilely synthesized. • The interpenetrated porous FSP-f exhibited effective removal of phosphate. • FSP-f displayed preferable selectivity of phosphate in aqueous solution. • FSP-f can be easily separated and regenerated by 0.01 M NaOH. A novel strategy to fabricate ferric sponge-like bulk adsorbent (FSP-f) for effective phosphate adsorption and recovery was proposed by anchoring β-FeOOH into the polyacrylamide gel network via a rapid and facile free-radical polymerization. Additionally, a foaming method was employed during the fabrication to establish interpenetrated porous structure inside the bulk material. The resultant FSP-f was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Batch adsorption experiments were carried out to understand the kinetics and isotherm as well as the influences of solution pH and coexisting anions on the removal of phosphate. Also, the regeneration and reusability experiments were performed. Results showed that FSP-f possessed abundant hierarchical open-pore structures and numerous β-FeOOH were randomly dispersed inside the pores. The porous morphology allowed the active sites to be fully exposed, thus making FSP-f perform the approximate adsorption capacity as PF (Powder form of FSP-f). The optimal solution pH for phosphate adsorption on FSP-f was determined at the weak acidic region and the mechanism of ion exchange, electrostatic interactions, and Lewis acid-base interactions dominated at different pH values. The co-existing ions effects on phosphate adsorption followed the order as HCO 3 − > SO 4 2− > Cl− > NO 3 − and FSP-f could still display preferable selectivity in the presence of competing anions at high concentration levels. Three cycles of adsorption-desorption experiments showed that FSP-f exhibited a satisfactory degree of reusability using 0.01 M NaOH as eluant. The results suggest that FSP-f has a great potential for practical application in the removal of phosphate from contaminated aquatic systems. [ABSTRACT FROM AUTHOR]

In this research, a novel manganese dioxide nanorod-anchored graphene oxide (MnO2 NRs/GO) composite was synthesized by a simple hydrothermal method for electrochemical sensing application. A highly sensitive electrochemical sensor for dopamine (DA) was constructed by modifying glassy carbon electrode (GCE) with MnO2 NRs/GO. The morphology and performance of the composite material and modified GCEs were investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD) and cyclic voltammetry (CV), respectively. The resultant MnO2 NRs/GO composite has a large electroactive area and shows excellent electrochemical activity toward DA. Under the optimal conditions, the DA sensor shows a linear response in the DA concentration ranges of 0.1 μM–0.08 mM and 0.08–0.41 mM with a low detection limit of 0.027 μM and a high sensitivity of 602.4 μA·mM−1·cm−2. The MnO2 NRs/GO composite provides a promising platform for the construction of a highly sensitive and selective sensor of DA. [ABSTRACT FROM AUTHOR]

In this research, we reported effective streptavidin-functionalized tin disulfide nanoflakes (SnS2 NFs) to develop an ultrasensitive electrochemical immunosensor for the bioanalysis of tumor markers. The streptavidin-functionalized SnS2 platform and immunosensor were characterized by scanning electron microscopy, electrochemical impedance spectroscopy, static water contact angle measurements and cyclic voltammetry. Biofunctionalized SnS2 NFs displayed a large specific surface area and outstanding hydrophilicity. These characteristics enhanced the loading efficiency and capacity of antibodies on the biosensing platform and ensured the biological activity of the immobilized protein biomolecules. Carcinoembryonic antigen (CEA) was chosen as the model analyte, and a wide linear range of 0.006–3.0 ng mL−1 with a low detection limit of 5 pg mL−1 for CEA was exhibited by the immunosensor. Human serum sample analysis was achieved through the CEA immunosensor with satisfactory results. Streptavidin-functionalized SnS2 NFs offer a potential platform for the expansion of electrochemical immunosensor applications. [ABSTRACT FROM AUTHOR]

The fabrication of chemically stable metal–organic frameworks for electrochemical sensors is essential to broaden their applications. In this study, the integration of a Zr-based metal–organic framework (UiO-66-NH2) with multi-walled carbon nanotubes (MWCNTs) was achieved by a one-pot solvothermal reaction. This composite was then characterized by scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, Fourier transform infrared spectroscopy, and contact angle measurements. The porous structure and unreacted amine groups provided by UiO-66-NH2 frameworks accompanied by the excellent conductivity of MWCNTs have made this composite an ideal electrode material for lead detection. After the optimization of MWCNT content and the detection conditions, the oxidation peak currents were proportional to lead concentrations in the range of 0.001–0.8 μmol L−1 with a low detection limit of 0.5 nmol L−1 (S/N = 3). More importantly, the well-preserved crystallinity of MWCNTs@UiO-66-NH2 after 80 cycles and after being soaked in different pH aqueous solutions indicates the promising application of this sensor for real samples. Satisfactory recoveries were achieved when this sensor was used to detect lead in real samples. Furthermore, the excellent stability of this composite makes it possible to be employed in other fields, including extreme acidic media. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis of novel nanosized reduced graphene oxide@polystyrene nanospheres (rGO@PS NSs) through an electrostatic interaction method, and further their exploitation for highly sensitive label-free electrochemical immunoassay applications. These rGO@PS NSs provide a universal and promising carrier platform to develop excellent biosensors for clinical screening and diagnostic applications. [ABSTRACT FROM AUTHOR]

Multiwalled carbon nanotubes coated with cobalt(II) sulfide nanoparticles were prepared and used for immobilization of glucose oxidase (GOx) to obtain an electrochemical glucose biosensor. The nanocomposite was synthesized through an in-situ hydrothermal method and characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and electrochemical impedance spectroscopy. The results show that the nanocomposite possesses a large specific surface area and apparently enhances the direct electron transfer between GOx and the surface of the electrode, best at a potential near −0.43 V (vs. SCE). The immobilized GOx retains its good bioactivity even at a high surface coverage of 30 pmol cm−2. Under the optimum conditions. The biosensor exhibits a wide linear range (from 8 μM to 1.5 mM), a high sensitivity (15 mA M −1 cm−2), and a 5 μM detection limit (at S/N = 3). The sensor is selective, acceptably repeatable, specific and stable. [ABSTRACT FROM AUTHOR]

Non-invasive wearable sweat glucose sensors are expected to be highly desirable for personalized diabetes management. Therefore, developing facile, convenient, and scalable manufacturing method of such wearable sensors is urgently needed. Herein, we report a simple and low-cost stamping-vacuum filtration dry transfer (SVFDT) method for construction of a wearable sweat glucose electrochemical sensor. In this patch, a three-electrode array template was made by using a polyvinyl chloride (PVC) stamp, followed by the preparation of multiwalled carbon nanotubes (MWCNTs)/polydimethylsiloxane (PDMS) (MP) film electrode using the vacuum-filtration dry transfer method. In addition, for further enhancing the conductivity of the electrode, another similar stamp with a raised surface dipping carbon nanotubes (CNTs) conductive coating was stamped on the surface of the MP electrode to obtain CNTs/MWCNTs/PDMS (CMP) electrode. CMP electrode was modified with the enzyme-like Ni-Co metal-organic framework (MOF) material which showed good electro-catalytic activity and achieved high sensitivity for glucose detection with a low detection limit of 6.78 μM and a wide linear range of 20 μM - 1.1 mM. More importantly, the Ni-Co MOF modified CMP (NCMP) electrode also displayed high stability under stretching and bending conditions. Finally, the sweat absorbent cloth was combined with the NCMP film electrode to form a wearable flexible electrochemical sensor patch, which could adhere to the skin to enrich sweat and realize real-time detection of sweat glucose with high accuracy. This SVFDT method can also be applied to the fabrication of other electronic devices. [Display omitted] • A wearable sweat glucose electrochemical sensor based on bimetallic MOF. • SVFDT method was used for prepare CMP film electrode. • NCMP film based sensor showed high performance for glucose detection. • An NCMP film based on-body sensor for real-time monitoring of sweat glucose. [ABSTRACT FROM AUTHOR]

NLRC4 gain-of-function variants are known to cause various autoinflammatory phenotypes, including familial cold autoinflammatory syndrome (FCAS4) and NLRC4 macrophage activation syndrome (NLRC4-MAS). However, to date, no study has linked NLRC4 gain-of-function variants to systemic lupus erythematosus (SLE). In this study, we identified a novel NLRC4 W655S variant in an SLE patient and her son, who had neonatal lupus complicated with macrophage activation syndrome. Our in vitro experiments demonstrated that the W655S NLRC4 increased ASC speck formation and mature IL-1β secretion compared to the wild-type NLRC4. In addition, the patient had elevated levels of IL-1β and IL-18 in both serum and PBMCs. RNA sequencing showed that NF-κB and interferon signaling pathways were significantly activated in the patient compared to healthy controls. Furthermore, gene set enrichment analysis revealed upregulation of NLRC4-related pathways in patient PBMCs. In conclusion, our study identified the NLRC4 W655S variant in a patient with SLE. This is the first report linking inflammasomopathy to monogenic SLE. Our findings suggest that inflammasome activation may be a critical driver in the pathogenicity of lupus, and autoinflammatory pathways may play important roles in the development of the disease. • NLRC4 W655S variant were identified in a patient with SLE. • W655S variant promotes NLRC4 inflammasome constitutive activation and overproduction of IL-1β and IL-18. • NF-κB and interferon signaling pathways were hyperactivated in the patient. [ABSTRACT FROM AUTHOR]

In spite of organic-inorganic perovskite emerging as a novel efficient light-harvesting material owing to their superior optical properties, excitonic properties, and electrical conductivity, the related applications are severely limited for their poor stability and selectivity. Herein, we introduced hollow carbon spheres (HCSs) and 2-(perfluorohexyl) ethyl methacrylate (PFEM) based molecularly imprinted polymers (MIPs) to dual-functionalize CH 3 NH 3 PbI 3. HCSs can provide perovskite load conditions, passivate perovskite defects, increase carrier transport and effectively improve its hydrophobicity. The perfluorinated organic compound based MIPs film can not only enhance the water and oxygen stability of perovskite, but also endow it specific selectivity. Moreover, it can reduce the photoexcited electron-hole pair recombination and prolong the electron lifetime. Benefiting from the synergistic sensitization of HCSs and MIPs, an ultrasensitive photoelectrochemical platform (MIPs@CH 3 NH 3 PbI 3 @HCSs/ITO) for cholesterol sensing was acquired with a very wide linear range of 5.0 × 10−14−5.0 × 10−8 mol/L and an extremely low detection limit of 2.39 × 10−15 mol/L. The designed PEC sensor exhibited good selectivity and stability, as well as practicality for real sample analysis. The present work extended the development of the high-performance perovskite and showed its broad application prospect for advanced PEC construction. [ABSTRACT FROM AUTHOR]

A photoelectrochemical (PEC) sensor based on hierarchically porous Cu-BTC/g-C 3 N 4 nanosheet (Cu-BTC/CN-NS, BTC = benzene-1,3,5-tricarboxylic acid) material was constructed for the first time. As a composite material, the hierarchically porous Cu-BTC can help to efficiently capture suitable pesticide molecules and accelerate signal transmission, while CN-NS possesses good optical performance. Under the irradiation of visible light, the Cu metal center can coordinate with the added glyphosate to form Cu-glyphosate complexes, leading to the increased steric hindrance of electron transfer and consequently resulted in an obvious decrease in photocurrent. Through this strategy, the constructed sensor can realize the detection of glyphosate from non-electroactive to electroactive. The results indicate that this photoelectrochemical sensor has a low detection limit of 1.3 × 10−13 mol L−1 and a wide detection range (1.0 × 10−12–1.0 × 10−8 mol L−1 and 1.0 × 10−8 ∼ 1.0 × 10−3 mol L−1). Furthermore, this Cu-BTC/CN-NS based sensor has the characteristics of short detection time and easy operation. It has great potential applications in photoelectrochemical analysis. [ABSTRACT FROM AUTHOR]

In this work, a water stable zirconium metal–organic framework functionalized with thiol groups was synthesized by a solvent-assisted ligand incorporation technique. The composites were characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, specific surface area measurement and field emission scanning electron microscopy. The prepared material was then used as a novel adsorbent for Cu(ii) removal from water. The experimental parameters associated with adsorption capability, such as the initial solution pH, contact time, and the presence of competing cations were investigated in detail. Under the optimal conditions, the adsorption follows a pseudo-second-order kinetics, and the equilibration time for the adsorption is 15 min. The Langmuir adsorption model was in better correlation with the isothermal adsorption data than the Freundlich model. The maximum Cu(ii) adsorption capacity reached up to 42.70 mg g−1. Quantitative recovery of Cu(ii) was achieved by using 0.1 mol L−1 HCl. The prepared adsorbent has fast adsorption efficiency, high adsorption capacity, and exceptional stability up to 50 adsorption/desorption cycles. It can be used as a promising candidate material for heavy metal ion removal and water treatment. [ABSTRACT FROM AUTHOR]

A facile and efficient synthesis of hemin containing metal–organic framework (MOF) nanocomposite was reported. Two dimensional (2D) Ni–MOF nanosheets have been used as a new type of matrix material to immobilize hemin. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS)–mapping, thermal gravity analysis (TGA) suggest the hemin is uniformly distributed in the Ni–MOF nanosheets. Ultraviolet–visible spectroscopy (UV–vis) analysis shows that hemin molecules are combined with MOFs nanosheets through π–π interaction. Electrochemical study indicates the Ni–MOFs/Hemin nanocomposite exhibits high electro–catalytic activities for H 2 O 2 reduction and the biosensor offers high performance with a low detection limit of 0.2 μM and a wide linear range of 1 μM–0.4 mM. Furthermore, the Ni–MOFs/Hemin nanocomposite based biosensor displays high selectivity and stability owing to the protective effect of the 2D MOF nanosheets. More importantly, the biosensor was used to determine the H 2 O 2 levels in human serum and disinfectant samples with satisfactory results. [ABSTRACT FROM AUTHOR]

Abstract A novel NH 4 + voltammetric electrochemical biosensor was constructed by immobilizing glutamate dehydrogenase (GLDH)/Fe 3 O 4 /graphene (GR)/chitosan (CS) nanobiocomposite onto a glassy carbon electrode (GCE). On the GLDH/Fe 3 O 4 /GR/CS/GCE, GLDH catalyzed the reversible reaction, i.e., the reductive amination of α-ketoglutaric acid and the oxidative deamination of L-glutamate. The electrons produced in the enzymatic reactions were transferred to the surface of the electrode via the [Fe(CN) 6 ]3−/4− couple, which helped for the amplification of the electrochemical signal. The electrochemical detection of NH 4 + was based on the fact that the enhanced response current was proportional to the NH 4 + concentration. Owing to the combination of the advantages of the synergistic effects of Fe 3 O 4 nanospheres, GR and CS, a promising platform for NH 4 + sensing was provided. Under optimum conditions, the introduced biosensor had a linear range of 0.4–2.0 μM for NH 4 + with the detection and quantification limits of 0.08 and 0.27 μM, respectively. Moreover, the biosensor exhibited good sensitivity and excellent reproducibility. It could retain 91.8% of its original response after two weeks of storage at 4 °C, suggesting satisfactory stability. Additionally, the proposed biosensor was successfully applied to detect NH 4 + levels in PM 2.5 samples, indicating its feasibility for application in NH 4 +monitoring in the environmental fields. Graphical abstract fx1 Highlights • Fe 3 O 4 /graphene/chitosan nanocomposite was synthesized and characterized. • The proposed composite provided a good loading platform for glutamate dehydrogenase. • NH 4 + in PM 2.5 was successfully assayed by the developed biosensor. • This biosensor provided a convenient and low-cost method for NH 4 + detection in PM 2.5. [ABSTRACT FROM AUTHOR]

Highlights • A hierarchically Cu-BTC MOF based electrochemical sensor was firstly constructed for non-electroactive pesticide detection. • This MOF based sensor possesses wide detection range and low detection limit. • The sensor displays good reproducibility and stability, exhibiting good performance in real sample detection. Abstract An electrochemical sensor based on hierarchically Cu-BTC MOF material for non-electroactive glyphosate detection has been firstly constructed in this report. By using Cu-BTC frameworks as a detection matrix, the large specific surface area of the material can increase the electrode reaction site and further improve the detection performance. The electrochemical behavior of Cu-BTC frameworks for glyphosate detection was evaluated by cyclic voltammetry (CV). Under optimum conditions, differential pulse stripping voltammetry (DPV) is employed to detect glyphosate. The results show that the fabricated sensor displays ultralow detection limit (1.4 × 10−13 mol L-1) and wide detection range (1.0 × 10-12 to 1.0 × 10-9 mol L-1 and 1.0 × 10-9 to 1.0 × 10-5 mol L-1). Besides, this sensor possesses acceptable reproducibility and stability, as well as good selectivity against the major metabolite of glyphosate aminomethylphosphonic acid (AMPA) and other interference. Furthermore, this electrochemical sensor can also be applied to the detection of glyphosate in soybean. It is worth mentioning that this effectively Cu-BTC based sensor has great potential application in favorable and selective detection of organophosphorus pesticides in actual samples. [ABSTRACT FROM AUTHOR]

Abstract Quantitative detection of multiple chicken cytokines is a good evaluation of cell-mediated immunity in chickens after disease infection or vaccination. However, current assay methods for chicken cytokines cannot meet the needs of clinical diagnosis due to unsatisfactory sensitivity and low assay throughput. Herein, a sensitive chemiluminescence (CL) imaging immunosensor array has been developed for high-throughput detection of multiple chicken cytokines. The chicken cytokines immunosensor array was prepared by assembling different cytokine capture antibodies onto a disposable silanized glass chip, where horseradish peroxidase and antibody-conjugated gold nanoparticles were used as multienzymatic amplification probe for CL imaging signal amplification. By using a sandwich assay mode, the amplified CL signals from each sensing array cell were collected for quantitation. Using chicken interleukin-4 and chicken interferon-γ as model cytokines, this novel multiplexed and amplified method demonstrated simultaneous measurement of the two chicken cytokines in the linear ranges of 0.008–0.12 ng/mL and 0.005–0.20 ng/mL, respectively, which yields limits of detection down to 2 pg/mL and 3 pg/mL. The CL imaging array method reported here also demonstrated high specificity, good repeatability, and high stability and accuracy, providing a novel multiplex immunoassay strategy for highly sensitive and high-throughput detection of chicken cytokines and further disease diagnosis in poultry. Graphical abstract A novel multiplex immunosensor array for sensitive and high-throughput detection of multiple chicken cytokines is for the first time developed based on highly-sensitive chemiluminescence imaging coupled with a multienzymatic signal amplification probe. Image 1 Highlights • Multiplex immunosensor array for chicken cytokines was proposed for the first time. • Multiple chicken cytokines were simultaneously detected by sensitive CL imaging system. • The multiplex cytokines immunoassay has much better performance compared with current methods. • This work provides a novel strategy for sensitive and high-throughput multiplex immunoassay. [ABSTRACT FROM AUTHOR]

We report a new concept of a chemiluminescence imaging nanozyme immunoassay (CINIA), in which nanozymes are exploited as catalytic tags for simultaneous multiplex detection of cytokines. The CINIA provides a novel and universal nanozyme-labeled multiplex immunoassay strategy for high-throughput detection of relevant biomarkers and further disease diagnosis. [ABSTRACT FROM AUTHOR]