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A sodium alginate/chitosan solution was prepared by dissolving sodium alginate, chitosan, and glycerol in an acetic acid solution. This solution was then combined with a sodium carboxymethyl cellulose solution and the mixture was cast onto a glass plate and dried at a constant temperature of 60 °C. Then, a carboxymethyl cellulose/sodium alginate/chitosan composite film was obtained by immersing the film in a solution of a cross-linking agent, CaCl2, and air-drying the resulting material. First, the most advantageous contents of the three precursors in the casting solution were determined by a completely random design test method. Thereafter, a comprehensive orthogonal experimental design was applied to select the optimal mass ratio of the three precursors. The composite film obtained with sodium alginate, sodium carboxymethyl cellulose, and chitosan contents of 1.5%, 0.5%, and 1.5%, respectively, in the casting solution displayed excellent tensile strength, water vapor transmission rate, and elongation after fracture. Moreover, the presence of chitosan successfully inhibited the growth and reproduction of microorganisms. The composite film exhibited antibacterial rates of 95.7% ± 5.4% and 93.4% ± 4.7% against Escherichia coli and Staphylococcus aureus, respectively. Therefore, the composite film is promising for antibacterial food packaging applications.

With the acceleration of uh-voltage transmission project construction, transmission lines are becoming increasingly important to maintain the safe and stable operation of the power grid, and insulators are essential components of mechanical support and electrical connection in transmission lines. However, due to long-term environmental impact, insulators exposed deteriorate year by year. Therefore, it is necessary to detect the faulty insulator in advance, and to carry out the test in the operating state of the insulator string to identify and replace the faulty insulator string in time. However, the current method of detecting insulators in actual engineering is greatly affected by the environment, the test result is not accurate enough, the predictability is not good and the detection efficiency is low. The optical electric field sensor based on the Pockels effect of optical crystals can realize chargerd detection, improve detection accuracy, reduce environmental impact, and make the detection more stable, lower cost, better economy compared with methods widely used in the market, such as infrared detection method, ultraviolet detection method, sonic detection method, manual methods. Further consideration can be given to combining with drones to expand usage scenarios and improve detection performance for widespread use.

Herein, we develop a straightforward, metal-free, and acid-/base-free electrochemical C4-selective C − H deuteration of pyridine derivatives with economic and convenient D 2 O at room temperature. This strategy features an efficient and environmentally friendly approach with high chemo- and regioselectivity, affording a wide range of D-compounds, such as pyridines, quinolones, N -ligands and biorelevant compounds. Notably, the mechanistic experiments and cyclic voltammetry (CV) studies demonstrate that N -butyl-2-phenylpyridinium iodide is a crucial intermediate during the electrochemical transformation, which provides a general and efficient way for deuteration of pyridine derivatives. Despite the established C − H deuteration of pyridine derivatives synthetic methods with good D-incorporation, under milder conditions with easy operation procedures is still on the way. Here, the authors develop a straightforward, metal-free, and acid-/base-free electrochemical C4-selective C − H deuteration of pyridine derivatives with high selectivity and excellent D-incorporation at room temperature, which use D2O as economic and convenient D-source.

HighlightsA ficus microcarpa-like magnetic aerogel with macroscopical electromagnetic cooperative effect was fabricated through highly oriented self-assembly engineering.The highly oriented Ni chains with unique macroscopic morphology (~ 1 cm in length) were achieved for the first time via a special magnetic field-induced growth.The electromagnetic cooperative networks with uninterrupted and dual pathways spread through the entire aerogel skeleton, resulting in a remarkable electromagnetic wave performance at an ultrathin thickness of 1 mm.Electromagnetic cooperative strategy has been presented as a mainstream approach that can effectively optimize the matching thickness of dielectric loss dominant system. However, it is still challenging for dielectric–magnetic loss coexisting-type absorber to develop electromagnetic wave (EMW) performance with ultra-low matching thickness (≤ 1 mm). Breaking the limitation of traditional electromagnetic response at microscopic/mesoscopic scale, a ficus microcarpa-like magnetic aerogel with macroscopical electromagnetic cooperative effect was fabricated through highly oriented self-assembly engineering. The highly oriented Ni chains with unique macroscopic morphology (~ 1 cm in length) were achieved via a special magnetic field-induced growth. Strong magnetic coupling was observed in the Ni chains confirmed by the micromagnetic simulation. The deductive calculation validates that maintaining high value of electromagnetic parameters at high frequencies is the prerequisites of ultrathin absorber. The electromagnetic cooperative networks with uninterrupted and dual pathways spread through the entire aerogel skeleton, resulting in the impressive permittivity even at high frequencies. Consequently, the aerogel exhibits a remarkable EMW performance at an ultrathin thickness of 1 mm. Thus, based on the modulation of electromagnetic parameters, this work proposed a macroscopic ordered structure with the electromagnetic cooperative effect useful to develop a suitable strategy for achieving ultrathin EMW absorbers.

Edible films have gradually become a research focus for food packaging materials due to a variety of benefits, including environmental friendliness, good barrier properties, and good carrying capacity. In this experimental study, we used sodium alginate as a film-forming substrate, sodium carboxymethylcellulose as a modifier, and glycerol as a plasticizer, then Lactococcus lactis was added to film solutions to form bacteriostatic films via the tape casting method. With the addition of Lactococcus lactis, the films did not significantly change thickness, while the transparency decreased and a significant increase in red and yellow hues was observed. Meanwhile, the dispersion of bacterial cells in film solutions destroyed intermolecular interactions in the solutions during film formation and increased the volume of voids in the Lactococcus lactis-containing films, thereby slightly decreasing the tensile strength of the films, but significantly increasing water vapor permeability. Moreover, the films with added Lactococcus lactis showed significant bacteriostatic activity against Staphylococcus aureus at 4 °C. In a seven-day bacteriostatic test, the films with Lactococcus lactis added at a level of 1.5 g/100 g resulted in a decrease in the viable cell count of Staphylococcus aureus by at least four logarithmic units. This study of Lactococcus lactis-containing films has provided a new method and strategy for antibacterial preservation of foods.

In this study, PLA/TiO2 composites materials were prepared via electrospinning and solution casting processes. By testing the mechanical properties, water contact angle, water vapor permeability, and solubility of the composite nanofibers and films, the comprehensive performances of the two types of nanocomposites were analyzed. The results show that maximum tensile strengths of 2.71 ± 0.11 MPa and 14.49 ± 0.13 MPa were achieved for the nanofibers and films at a TiO2 content of 0.75 wt.%. Moreover, the addition of TiO2 significantly cut down the water vapor transmittance rate of the nanofibers and films while significantly improving the water solubility. Further, the antibacterial activity increased under UV-A irradiation for a TiO2 nanoparticle content of 0.75 wt.%, and the nanofiber and films exhibited inhibition zones of 4.86 ± 0.50 and 3.69 ± 0.40 mm for E. coli, and 5.98 ± 0.77 and 4.63 ± 0.45 mm for S. aureus, respectively. Overall, the performance of the nanofiber was better than that of the film. Nevertheless, both the nanocomposite membranes satisfied the requirements of food packaging materials.

High-complexity network models are challenging to execute on agricultural robots with limited computing capabilities in a large-scale pineapple planting environment in real time. Traditional module replacement often struggles to reduce model complexity while maintaining stable network accuracy effectively. This paper investigates a pineapple detection framework with a YOLOv7-tiny model improved via pruning and a lightweight backbone sub-network (the RGDP-YOLOv7-tiny model). The ReXNet network is designed to significantly reduce the number of parameters in the YOLOv7-tiny backbone network layer during the group-level pruning process. Meanwhile, to enhance the efficacy of the lightweight network, a GSConv network has been developed and integrated into the neck network, to further diminish the number of parameters. In addition, the detection network incorporates a decoupled head network aimed at separating the tasks of classification and localization, which can enhance the model’s convergence speed. The experimental results indicate that the network before pruning optimization achieved an improvement of 3.0% and 2.2%, in terms of mean average precision and F1 score, respectively. After pruning optimization, the RGDP-YOLOv7-tiny network was compressed to just 2.27 M in parameter count, 4.5 × 109 in computational complexity, and 5.0MB in model size, which were 37.8%, 34.1%, and 40.7% of the original YOLOv7-tiny network, respectively. Concurrently, the mean average precision and F1 score reached 87.9% and 87.4%, respectively, with increases of 0.8% and 1.3%. Ultimately, the model’s generalization performance was validated through heatmap visualization experiments. Overall, the proposed pineapple object detection framework can effectively enhance detection accuracy. In a large-scale fruit cultivation environment, especially under the constraints of hardware limitations and limited computational power in the real-time detection processes of agricultural robots, it facilitates the practical application of artificial intelligence algorithms in agricultural engineering.

Background and aim Hypertension and hyperlipidaemia are major risk factors for cardiovascular diseases, contributing to significant morbidity and mortality worldwide. Lifestyle interventions, including modifications in diet, nutrition, and physical activity, are commonly recommended, but their causal effects on these conditions remain uncertain. This study aims to explore the causal effects of these factors on hypertension and hyperlipidaemia using multivariate Mendelian randomisation analysis, providing insights for effective cardiovascular prevention strategies. Methods and results Genetic data related to physical activity, diet, and nutrition were obtained from public databases and analyzed using multivariate Mendelian randomisation. The analysis employed MR Egger, weighted median, and inverse variance weighting (IVW) methods, with tests for heterogeneity and multiplicity ensuring the reliability of the results. In the hypertension analysis, low-calorie diets showed a positive association in weighted median and IVW analyses, with weighted median analysis showing an association of 1.122 (95% CI: 1.014–1.243, P  = 0.026) and IVW analysis showing an association of 1.095 (95% CI: 1.013–1.184, P  = 0.023). However, MR Egger's analysis showed no significant association (association of 0.688, 95% CI: 0.411–1.155, P  = 0.230). Calcium supplements and dietary fibre did not demonstrate significant associations across all methods. Physical activity also did not show significant causal links with hypertension. Regarding hyperlipidaemia, calcium supplements exhibited significant effects across all methods, though with notable variation, while dietary fibre and physical activity showed no significant impacts. Conclusions The study suggests a positive association between low-calorie diets and hypertension, as indicated by significant results from weighted median and IVW analyses. Other dietary factors, physical activity, and calcium supplementation exhibited varied or non-significant effects on hypertension and hyperlipidaemia. These findings highlight the need for further research to understand the underlying mechanisms and support the development of effective public health interventions.

In this study, we fabricated polyvinyl alcohol (PVA)/chitosan (CS) bilayer films by casting and investigated the effects of preparation conditions and CS content (2, 2.5, or 3 wt.%) on the ability of these films to preserve packaged strawberries. The best performance was achieved at a CS loading of 2.5 wt.% (ultrasound time, 25 min); the strain and stress values were 143.15 ± 6.43% and 70.67 ± 0.85 MPa, respectively, oxygen permeability was 0.16 ± 0.08 cm2·m2·day−1·MPa−1, water vapor permeability was 14.93 ± 4.09 g·cm−1·s−1·Pa−1, and the shelf life of fresh strawberries packaged in the PVA/CS 2.5 wt.% bilayer film was determined to be 21 days at 5 ± 2 °C and a relative humidity of 60 ± 5%. Treatment with PVA/CS bilayer films prevented the decrease in the firmness of strawberries during storage (21 days). The evaluated physicochemical parameters (weight loss, decay, firmness, titratable acidity, soluble solid content, ascorbic acid content, and color) indicated that treatment with PVA/CS bilayer films led to better maintenance of the fruit quality. We believe that our study makes a significant contribution to literature because it paves the way to the fabrication of smart packaging materials and facilitates the commercialization of fresh strawberries as an important health food.

In this experiment, we studied the effect of poly(lactic acid)/poly(butylene adipate-co-terephthalate) (PLA/PBAT) blend films on the efficiency of passion fruit preservation at 20 °C. The weight loss, shrinkage index, firmness, and total sugar of passion fruit packaged with PLA/PBAT films had no significant differences compared with PE films during 21 days (p > 0.05). PLA/PBAT films can more effectively reduce the rising of ethanol content and delay the total acid, ascorbic acid, and sensory evaluation. Compared with unpackaged (CK) and polyethylene (PE) films, PLA/PBAT films are more conducive to preserve the overall flavor of passion fruit during storage time, in agreement with sensory evaluation, tested by E-nose, E-tongue, and GC-MS, which also proved that it can effectively maintain the edible quality of passion fruit during storage time. We believe that our study makes a significant contribution to literature because it paves the way to the generalization and application of packaging films based on composite antibacterial polymers and facilitates the commercialization of fresh passion fruit as an important health food.