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•MAPB QDs@SiO2 nanocomposites are synthesized by a one-pot procedure.•MAPB QDs@SiO2 shows greatly enhanced ECL response in an organic electrolyte.•Ultrasensitive molecularly imprinted ...ECL sensors are constructed to detect AFB1.•This sensing platform is successfully applied for AFB1 assay in real corn oil.
Mycotoxins contamination, especially aflatoxin B1 (AFB1) in edible oils, is a health hazard. Therefore, AFB1 trace analysis methods are urgently needed. Electrochemiluminescence (ECL) is a popular sensing method because of its low background interference and high sensitivity. However, existing ECL assays for AFB1 detection are based on aqueous rather than oil systems. Herein, we report a CH3NH3PbBr3 quantum dots (MAPB QDs)@SiO2-based ECL sensor for AFB1 quantification in corn oil using an organic electrolyte. The luminophore loading and stability of the MAPB QDs@SiO2 particles were significantly improved compared to those of bulky MAPB materials, resulting in an enhanced ECL response. Further, exploiting molecular imprinting technology, an ECL sensor for AFB1 detection with an ultra-low detection limit of 8.5 fg/mL was prepared. The reliability of the sensor was confirmed by comparable recoveries of corn oil samples with those obtained by high-performance liquid chromatography, indicating its potential for food safety evaluation.
A reliable and practical Reformatsky reaction of ethyl iodide acetate with ketones for the synthesis of chiral β‐hydroxyl carbonyl compounds in good yields and excellent enantioselectivities is ...presented. A readily available dihydroindole derivative was used as chiral catalyst, ethyl iodide acetate was the nucleophile, and Me2Zn was the zinc source. The presence of air was found to be essential for the efficient construction of new carbon–carbon bonds through a radical pathway.
Asymmetric Reformatsky reaction of ethyl iodide acetate with ketones was realized via the initiation of Me2Zn and the proper stereocontrol of the chiral Zn‐indolinylmethanol complex. Various chiral β‐hydroxyl carbonyl compounds were obtained in good yields and excellent enantioselectivities (up to 97 % ee).
Flexible and wearable chemical sensors show great capability and potential in retrieving physiologically related chemical or biochemical information from elastic and curvilinear living bodies. ...However, so far, no flexible electrochemiluminescence (ECL) device has been reported, though ECL measurements have been extensively investigated and widely applied in many fields. Herein, we for the first time designed and fabricated a flexible ECL sensor by immobilizing highly luminescent nanospheres on Au nanotube (Au NT) networks, and subsequently coating an elastic molecularly imprinted polymer (MIP) thereon. The as-prepared flexible ECL platform displayed successive and desirable mechanical compliance while generating a very stable ECL signal during deformation, facilitating highly selective detection of physiologically relevant chemicals from bodies. On-body wearable sampling and subsequent detection of lactate and urea from sweat showed the ECL performance of this sensor displaying desirable fidelity, reusability and high stability against disturbance. This work successfully incorporated the ECL sensing model into a flexible and wearable device, therefore providing a promising new path for non-invasively monitoring the products of metabolism for health care and biomedical investigations.
Flexible and wearable electrochemiluminescence sensor was successfully designed and fabricated for non-invasively monitoring the metabolism products in sweat.
Construction of CuO-g-C3N4 heterojunction-based MIP-PEC sensors for ultrasensitive detection of aflatoxin B1.
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•The heterostructured CuO-g-C3N4 nanocomposites were facilely synthesized ...by in-situ growth of CuO on g-C3N4 nanosheets.•The prepared CuO-g-C3N4 heterojunction improved separation efficiency of electron-hole pairs and reinfored PEC signal.•Further combining with molecularly imprinting technique, a novel MIP-PEC sensor has been developed for AFB1 detection.•The work offers a detection limit of 6.8 pg mL−1 for AFB1, showing the potential application of PEC sensors in food safety.
Here, copper oxide-graphitic carbon nitride (CuO-g-C3N4) nanocomposites were facilely prepared and used as an efficient photosensitive material to construct a highly sensitive photoelectrochemical (PEC) sensor. The CuO-g-C3N4 nanocomposites were directly synthesized by in-situ growth of CuO on g-C3N4 nanosheets to form p-n heterojunction. The optical absorption of CuO-g-C3N4 nanocomposites was efficaciously broadened towards visible region through CuO doping. The heterostructured CuO-g-C3N4 permitted the photogenerated electrons of g-C3N4 to transfer to CuO and meanwhile the photogenerated holes of CuO to migrate to g-C3N4 under visible light irradiation. The effective carriers generation, separation and transfer processes endows CuO-g-C3N4 nanocomposites unique and greatly enhanced cathode photocurrent response as confirmed by a series of PEC studies. Further combining with molecular imprinted polymer (MIP) which acts as a recognition unit, we construct a favorable molecular imprinted polymer photoelectrochemical (MIP-PEC) sensor with high sensitivity for target aflatoxin B1 (AFB1) detection. Under optimal conditions, the proposed MIP-PEC sensor was successfully employed for AFB1 quantitative determination with a linear range of 0.01 ng mL−1 to 1 μg mL−1 and a detection limit of 6.8 pg mL−1. In addition, the sensor has excellent selectivity under high concentrations of interfering substances circumstance. The satisfactory AFB1 recoveries in maize solution illustrated the credible application of the proposed MIP-PEC sensors for real samples, indicating promising potential in food safety control.
Distributed coherent aperture radar (DCAR) is a critical advancement in next-generation radar technology. Traditional DCAR relies on quadrature signals to gather target parameters before transmitting ...coherent signals, facing the challenge of time synchronization and parameter acquisition accuracy. This article tackles the challenges by transforming the coherence problem into an optimization issue, achieved by quantifying the degree of coherence of the echo signal. We employ an optimization algorithm to adjust the transmission time of each node, thereby ensuring that signals coherently accumulate at the target location. Furthermore, we propose a smoothing optimization technique to counter the fitness function's "multipeak" and "black box" attributes. By employing the barycentric interpolation to construct a pseudofunction, this technique facilitates the smoothing of the fitness function, speeds up convergence, and minimizes the probability of falling in local optima. For scenarios involving moving targets, a Kalman filter is embedded within the optimization algorithm to facilitate target motion prediction and preemptively resolve temporal errors in parameter acquisition, thereby enhancing real-time tracking capabilities. Theoretical analyses and simulation results demonstrate the efficacy of the proposed method in facilitating coherent target tracking. This method improves the signal-to-noise ratio while reducing the need for precise carrier synchronization. In addition, the proposed smoothing optimization technique accelerates convergence rates, reduces the possibility of convergence to a local optimum, and can be applied to optimization problems with similar properties.
•An ingenious electrochemiluminescence (ECL) assay was developed for sensing.•Methylamine perovskite quantum dots (MP QDs) wrapped by ZIF-8 had enhanced ECL.•Good water-stability and enhanced ECL ...mechanism of MP QDs@ZIF-8 were investigated.•Ultra-sensitive aflatoxin B1 (AFB1)-imprinted ECL sensors were constructed.•The feasibility of this ECL sensor was verified in corn sample for AFB1 detection.
Aflatoxin B1 (AFB1) that is prone to contaminate corns brings a serious threat to human health. Therefore, it is of great significance to construct novel detection methods for AFB1 tracing. Here, methylamine perovskite quantum dots (MP QDs) encapsulated by ZIF-8 metal–organic frameworks (MP QDs@ZIF-8) were prepared and then ultra-stable electrochemiluminescence (ECL) sensors were developed. By the confinement of cavities structure, multiple MP QDs were crystallized and embedded inside ZIF-8 to form MP QDs@ZIF-8, achieving stable and robust ECL responds in aqueous environment. Further combined with AFB1-imprinted polymer, the constructed ECL sensor showed good selectivity and ultra-sensitivity (the detection limit was 3.5 fg/mL, S/N = 3) with a wide linear range from 11.55 fg/mL to 20 ng/mL for AFB1 quantification. Satisfactory recoveries in corn samples indicated the reliable practicability of the proposed sensor for AFB1 assay. This work provided a novel pathway in designing high-performance ECL sensing platform for food safety.
Large deformation of soft rock roadway has always been a major difficulty in deep mining practices. This paper describes a case study of the failure mechanisms and stability control technology of ...deep roadway with soft rock mass in Xin'an coal mine in Gansu Province, China. Rock mass properties around the roadway are evaluated using geological strength index (GSI) based on the field data and the mechanical properties of intact rock specimens. The Universal Discrete Element Code (UDEC) software program is adopted to establish the numerical model of a ventilation roadway in Xin'an coal mine, and the micro-parameter calibration is conducted with the rock mass properties. The failure process of roadway under unsupported and primary support conditions is simulated; the deformation, stress and crack evolution characteristics were clearly illustrated. Failure first appears around the roadway surface because there is a high stress concentration around the roadway surface after excavation; the failure area propagates further into the deep surrounding rock as the stresses applied on the surface gradually decreases, finally resulting in a large zone of stress relaxation. There exists a large scale of tensile failure in the shallow rock, which leads to swelling and fracturing around the roadway. The primary support is low in strength with no support in the floor, which results in serious floor heave, side shrinking and roof subsidence. A new “bolt-cable-mesh-shotcrete+shell” combined support is proposed to support the ventilation roadway. The monitoring data in the experiment section show that the new support design successfully controls the large deformation of the roadway, which can provide helpful references for support designing of engineering in deep soft rock roadway.
•Evaluate rock mass properties around the roadway using GSI.•Establish the numerical model of a ventilation roadway in Xin'an coal mine using UDEC.•Obtain the deformation and stress behavior of roadway under various support conditions.•Analyze the crack evolution process of roadway under various support conditions.•Propose and validate a new “bolt-cable-mesh-shotcrete+shell” combined support mode.
Disinfection is an indispensable water treatment process for killing harmful pathogens and protecting human health. However, the disinfection has caused significant public concern due to the ...formation of toxic disinfection by-products (DBPs). Lots of studies on disinfection and DBPs have been performed in the world since 1974. Although related studies in China started in 1980s, a great progress has been achieved during the last three decades. Therefore, this review summarized the main achievements on disinfection and DPBs studies in China, which included: (1) the occurrence of DBPs in water of China, (2) the identification and detection methods of DBPs, (3) the formation mechanisms of DBPs during disinfection process, (4) the toxicological effects and epidemiological surveys of DBPs, (5) the control and management countermeasures of DBPs in water disinfection, and (6) the challenges and chances of DBPs studies in future. It is expected that this review would provide useful information and reference for optimizing disinfection process, reducing DBPs formation and protecting human health.
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MicroRNAs (miRNAs) have been perceived as important regulators in multifarious biological processes as well as potential biomarkers in clinical diagnosis. Exploring high-efficient sensing platforms ...for tracing miRNAs in complex biological samples is of great vital. Herein, an ultrasensitive and enzyme-free electrochemical biosensor was constructed based on integration of efficiently catalytic electrochemical−chemical−chemical (ECC) redox cycling with target-induced magnetic DNAzyme walker. Employing porous and easily functionalized covalent organic framework (COF) as carriers, Pt@COF nanospheres (Pt@COF NSs) were facilely prepared by in-situ reduction of platinum precursors in the nanopores-structure of COF. This not only addressed the inevitable migration of pure Pt nanoparticles, but endowed Pt@COF NSs with desirable stability and excellent catalytic activity to boost ECC redox cycling for effective signal enhancement. On this basis, a target-induced magnetic DNAzyme walker was obediently induced to recognize, separate and convert low-abundant miRNA-21 targets into plentiful output DNA chains for accumulated signal amplification. Finally, the as-prepared robust biosensor manifested highly sensitive and selective determination of miRNA-21 with a wide detection range from 100 aM to 10 pM and a low detection limit of 47.5 aM. Meanwhile, the credible detectability and anti-interference were also demonstrated in serum and cell samples, indicating its promising application toward diseases warning.
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•Pt@COF nanocatalyst was gained by in-situ growth of Pt in porous COF carriers.•The catalytic Pt@COF-based redox cycling greatly boosted electrochemical signal.•A magnetic DNAzyme walker achieved miRNA-21 recognition, separation and conversion.•This signal amplification system was used for ultrasensitive miRNA-21 detection.
Malnutrition has been reported to be associated with reduced survival and deficient anticancer immunity, and undernourishment is a frequent comorbidity in head and neck cancer (HNC) patients. In this ...study, we evaluated the relationship between nutritional status and immunologic factors, and its prognostic value for HNC. We retrospectively reviewed 212 HNC patients who had undergone a nutrition evaluation based on the Patient‐Generated Subjective Global Assessment (PG‐SGA) and curative radiotherapy (RT). The role of nutritional status in the prognosis of HNC and its correlation with anticancer immune response was assessed in HNC patients, and in the 4‐nitroquinoline 1‐oxide (4NQO)‐induced tongue tumor animal model. Our data revealed that malnutrition (high PG‐SGA scores) was significantly associated with more advanced disease, lower body mass index, lower RT completion rates, and reduced survival. Patients in the group with high PG‐SGA scores had a higher neutrophil‐to‐lymphocyte ratio, higher proportion of myeloid‐derived suppressor cells (MDSCs), and elevated IL‐6 levels in the peripheral circulation. Patients with increased PG‐SGA scores following treatment were more likely to developing locoregional failure. In the 4NQO‐induced tumor model, nutritional supplementation decreased the rate of invasive tumor formation and attenuated the immune‐suppressive microenvironment. Following ectopic tumor implantation in an immunocompetent host, nutrition supplements decreased tumor growth in association with attenuated MDSC recruitment and lower IL‐6 expression. In conclusion, malnutrition by PG‐SGA was associated with poor prognosis in HNC patients. Based on the data of HNC patients and the 4NQO‐tumor model, adequate nutritional supplementation might improve the prognosis associated with augmented anticancer immunity.
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