A novel molecularly imprinted nanomaterial (Eu (BTC)-MPS@MIP) was synthesized on the surface of silanized europium-based metal–organic frameworks (Eu (BTC)-MPS) using 1, 3, 5-benzotrioic acid (H
3
...BTC) as a ligand. The resulting Eu (BTC)-MPS@MIP was applied to constructing a smartphone sensing platform for the sensitive and selective detection of clothianidin (CLT) in vegetables. The synthesized Eu (BTC)-MPS@MIP demonstrated the successful formation of a typical core–shell structure featuring a shell thickness of approximately 70 − 80 nm. The developed sensing platform based on Eu (BTC)-MPS@MIP exhibited sensitivity in CLT detection with a detection limit of 4 µg/L and a linear response in the range 0.01 − 10 mg/L at excitation and emission wavelengths of 365 nm and 617 nm, respectively. The fluorescence sensing platform displayed excellent specificity for CLT detection, as evidenced by a high imprinting factor of 3.1. This specificity is primarily attributed to the recognition sites in the molecularly imprinted polymer (MIP) layer. When applied to spiked vegetable samples, the recovery of CLT ranged from 78.9 to 102.0%, with relative standard deviation (RSD) values falling between 2.2 and 6.2%. The quenching mechanism of Eu (BTC)-MPS@MIP toward CLT can be attributed to the inner filter effect (IFE), resulting from the optimal spectral overlap between the absorption spectrum of CLT and the excitation spectra of Eu (BTC)-MPS@MIP. The proposed method has the potential for extension to the detection of other pesticides by replacing the MIP recognition probes.
Graphical abstract
Hen eggs are one of the most popular foods worldwide, and their safety is critical. Employing 16S rRNA full-length sequencing is an effective way to identify microorganisms on or in eggs. Here, hen ...eggs collected from poultry farms over four seasons, as well as from markets in Shanghai, were analyzed with third-generation sequencing. Firmicutes (44.46%) and Proteobacteria (35.78%) were the two dominant phyla, and Staphylococcus, Acinetobacter, Aerococcus, Psychrobacter, and Lactobacillus were the dominant genera. The dominant genera on the eggshell surfaces from the farms varied with the seasons, and the highest contamination of Staphylococcus (32.93%) was seen in the eggs collected during the summer. For the market samples, Pseudomonas was the most abundant in content, with Staphylococcus being the most-often genera found on the eggshell surfaces. Moreover, several potential pathogenic bacteria including Riemerella anatipestifer (species), Klebsiella (genus), and Escherichia/shigella (genus) were detected in the samples. The results revealed the impacts of weather on the microbiota deposited on an eggshell’s surface, as well as the impacts due to the differences between the contents and the surface. The results can help disinfect eggs and guide antibiotic selection.
A novel rapid and cost-effective pre-processing method for the simultaneous determination of pyrethroid pesticides in vegetables has been developed and validated. The process of pesticide extraction ...was carried out by the QuEChERS (quick, easy, cheap, effective, rugged and safe) method combined with filtration by filter paper, and cleanup was carried out by the multi-plug-filtration-cleanup (m-PFC) method with no centrifuge program during the whole process. The pre-processing method is optimized for gas chromatography (GC). The process is convenient and time saving, requiring just a few seconds per sample. The recovery rate (70–120%), limit of detection (0.0001–0.007 mg/kg), precision (0.2–9.3%) and accuracy for each analyte were determined in 10 representative vegetables with good results. Finally, the feasibility of the developed method was further confirmed by the successful determination of pyrethroid-pesticide residues in pyrethroid-containing practical samples within the processing method coupled with thin-layer chromatography and a colloidal-gold test strip.
•The inhibitory effect of Pb2+-induced G-quadruplex on CRISPR-Cas12a trans cleavage has been investigated.•A simple fluorescence resonance energy transfer method has been explored to detect Pb2+.•The ...method can be successfully applied to analyze Pb2+ in tea drink and milk.
In this work, the inhibition of clustered regularly interspaced short palindromic repeats (CRISPR) - CRISPR associated protein (Cas) trans-cleavage by Pb2+-induced G-quadruplex has been firstly explored to detect Pb2+ in tea beverage and milk. In absence of Pb2+, the Na+-induced G-quadruplex can be cleaved by CRISPR-Cas12a. In contrast, Pb2+ can competitively combine with G-quadruplex, resulting in its conformational changes and resistance to trans-cleavage of CRISPR-Cas12a. Therefore, the fluorescence resonance energy transfer can happen. Pb2+ can be detected in a linear range from 100 nM to 5 µM with a lowest detection limit of 2.6 nM and a relative standard deviation of 4.32%. In summary, this work not only provides a new method for Pb2+ detection based on its induced G-quadruplex inhibition on CRISPR-Cas12a trans-cleavage, but also broadens the application of CRISPR-Cas system for heavy metal analysis in the field of food safety.
Background
Previous research in the field of content and language integrated learning (CLIL) has not yet comprehensively investigated the interaction between learners' expertise and the instructional ...effectiveness.
Aims
Taking cognitive load theory as the theoretical framework, a study was conducted to investigate the expertise reversal effect on learning English and mathematics simultaneously: whether an integrated approach (i.e. learning both English and mathematics simultaneously) could facilitate the acquisition of mathematic skills and English linguistic skills as a foreign language more effectively and efficiently than a separated learning approach (i.e. learning Mathematics and English separately).
Materials
The materials for the integrated learning approach were in English‐only, and the materials for the separated learning approach were in English‐and‐Chinese. Both sets of materials were given as reading content for teaching mathematic skills and English as a foreign language.
Methods
The study adopted a 2 (language expertise: low vs. high) × 2 (instruction: integrated vs. separated) between‐subject factorial design with instructional approaches and learners' expertise in English as independent variables, the learning performance in Mathematics and English with the cognitive load ratings as the dependent variables. Sixty‐five Year‐10 students with lower expertise in English and 56 Year‐2 college students with higher expertise in English in China were recruited and allocated to two instructional conditions respectively.
Results
An expertise reversal effect was confirmed: the English and mathematics integrated learning approach was more effective for higher expertise learners while the English and mathematics separated learning condition was more beneficial for lower expertise learners.
A novel electrochemical paper-based microfluidic chip was firstly developed to simultaneously detect cadmium (Ⅱ) and lead (Ⅱ) in vegetable and fruit samples. The patterned filter paper was prepared ...through the printing of three-electrode patterns on filter paper using an automatic screen-printing machine. Portable and low-cost (less than $1) electrochemical paper-based chips are prepared by filling conductive ink and hot pressing. The paper-based chip could realize signal amplification through gold nanoparticles and seed solutions. Cadmium (Ⅱ) and lead (Ⅱ) were sensitively detected by their aptamers labeled with methylene blue and ferrocene, separately. Under the optimal experimental parameters, the paper-based chip detected cadmium (Ⅱ) and lead (Ⅱ) as low as 23.31 and 46.23 pmol/L (3σ) with a wide linear range from 0.1 to 1000 nmol/L and exhibited excellent selectivity. The RSD was 6.41% (cadmium (Ⅱ)) and 4.20% (lead (Ⅱ)). Compared with other methods, the paper-based chip could complete the detection within 15 min and could be stored at −20 °C for 5 days. Furthermore, the results for vegetable and fruit samples were agreed with the results of the graphite furnace atomic absorption spectrophotometer, in which the recovery rates were 93.20%–95.80%.
An electrochemical paper-based chip for simultaneous detection of cadmium and lead according to changes in electrochemical signals was established. Display omitted
•An ultrasensitive electrochemical paper-based microfluidic chip was developed to simultaneously detect cadmium (Ⅱ) and lead (Ⅱ) in fruit and vegetable.•The electrochemical paper-based chip was simple to make through an automatic screen-printing machine, easy to carry and low cost (less than $1).•The electrochemical paper-based chip displayed low detection limit of 46.23 pmol/L for lead (Ⅱ) and 23.31 pmol/L for cadmium (Ⅱ).
Shadow (Guo et al., 2021) is a lightweight block cipher based on a new logical combination method of AND-RX operation and the generalized Feistel structure with high diffusion and excellent ...performance in hardware implementation. In this paper, the components and structure of Shadow cipher are researched, and based on MILP automatic search algorithms for differential trails the 2-round iterative differential characteristics are obtained, then the full-round differential characteristics of both Shadow-32 and Shadow-64 are given. Moreover, targeting Shadow-32, we conduct 32-bit round-key recovery attack by using four 13.5-round differential trails, and the experimental verification shows that the time complexity is 226.02 and space complexity is 214.1. Recovering the 64 master key bits need to solve a system of multivariate equations over F2 with the time complexity more than 250.69. For Shadow-64, the process of recovering the master key is similar. Finally, we analyze the reasons for the insecurity of the Shadow cipher that may help to improve the cryptographic performance of the Shadow or provide help for a new block cipher design.
The dual-frequency ultrasound-assisted enzymatic digestion (DUED) technique was developed for synchronous green extraction of five heavy metal ions in root vegetables. The combination of α-amylase, ...cellulase, and papain showed significant advantageous in extracting heavy metal ions. Under optimized dual-frequency ultrasonic conditions, the extraction rates of Cr, As, Cd, Pb, and Hg in carrots reached 99.04%, 105.88%, 104.65%, 104.10%, and 103.13% respectively. And the extraction process is highly efficient, completing in just 15 min. Compared to conventional microwave-assisted acid hydrolysis method, this technique eliminates the need for high-temperature concentrated acid, enhancing its environmental sustainability while maintaining mild reaction conditions, making it ideal for biosensors application. Additionally, simultaneous extraction and detection of four heavy metals in lotus roots were successfully achieved by using DUED and a fluorescent paper-based microfluidic chip. The obtained results are consistent with those obtained using conventional methods.
•Green pretreatment method for simultaneous extraction of five heavy metal.•The screening was made for a compound enzyme formula.•The extraction duration lasted for 15 min, yielding a recovery rate ranging from 85% to 115%.•A DUED-fluorescent biosensor was successfully established and applied to the analysis of lotus root samples.
In this study, a novel fluorescent immunochromatographic assay (ICA) strip based on quantum dot encoded multicolour nanobead (QB) was developed to detect three neonicotinoid insecticides in the ...vegetable samples simultaneously. The results showed that three QBs with red-, yellow- and green-emitting were successfully synthesized by embedding different ratios of two kinds of hydrophobic CdSe/ZnS QDs (λem = 565 nm and λem = 620 nm) into the polymer matrix. The obtained three QBs were further used to label the monoclonal antibodies (mAbs) specific to imidacloprid (IMI), clothianidin (CLT) and thiamethoxam (TMX). The resultant QB@mAbs nanoprobes, including QBred@IMI mAbs, QByellow@CLT mAbs and QBgreen@TMX mAbs, presented excellent monodispersity with distinguishable emission colours. Furthermore, the fabricated QB-ICA strip based on QB@mAbs nanoprobes achieved a more sensitive simultaneous detection for three neonicotinoids with the detection limits of 14.58 ng/mL for IMI, 0.27 ng/mL for CLT, and 0.36 ng/mL for TMX, respectively. This was better than most of the conventional based enzyme-linked immunosorbent assay (ELISA). Moreover, the QB-based ICA strips also exhibited good stability and specificity for the multiplex detection of IMI, CLT, and TMX. In the spiked Chinese cabbage samples, the recovery of IMI, CLT, and TMX ranged from 72.08% to 98.70%, with RSD values ranging from 3.60% to 13.09%. In brief, the great performance of the developed QB-ICA approach demonstrates its potential for simultaneous and quantitative neonicotinoids detection in agricultural products.
•The mAbs specific to IMI, CLT and TMX were labelled by quantum dot encoded multicolour nanobead (QB).•Three QB@mAbs were used to fabricate the QB-ICA system for the detection of IMI, CLT and TMX.•The QB-ICA strip has a high sensitivity for IMI, CLT and TMX detection with a LOD of 14.58, 0.27 and 0.36 ng/mL.•This work achieves the simultaneous detection of three neonicotinoids via ICA.
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