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[Objective] A lightweight SE-PPM algorithm (SAPMDSNet) was proposed to solve the problems of slow speed, misclassification and difficulty in feature extraction in traditional positive and subgroup classification of natural state tobacco leaves. [Method] Based on the lightweight ShuffleNetV2 net-work, the training speed of the network model was accelerated by reducing the network convolution depth and evolving the activation function. Then, the channel attention SE module was introduced to enhance the haracteristic differences between channels, improve the representation ability of the network model and a-void the group misclassification caused by the regionalization. Finally, the pyramid pooling module PPM was embedded to integrate the exposure characters and global information by aggregating context information, and the in-house tobacco leaf data set was used and compared with other models. [Result] The SAPMDSNet network model achieved relatively high classification results with accuracy of 91.09% and FLOPs of 151.70 M. Compared with the original ShuffleNetV2 model and the lightweight GhostNet model, the FLOPs were slightly increased by 2.65% and 2.84%, and the accuracy was increased by 2.72% and 21.13 %, respectively. MobileNetV2, DenseNet and SqueezeNet achieved recognition accuracies of 87.02%, 89.53% and 87.60%, which were close to the proposed model, but their FLOPs were significantly higher. [Conclusion] The constructed SAPMDSNet network model improved the classification accuracy of positive and sub-group tobacco leaves in natural state with better overall performance, which provides a new method for primary screening of tobacco leaves. [ABSTRACT FROM AUTHOR]

Recently, pollution caused by the heavy metal Cd has seriously affected the environment and agricultural crops. While Sinapis alba is known for its edible and medicinal value, its tolerance to Cd and molecular response mechanism remain unknown. This study aimed to analyze the tolerance of S. alba to Cd and investigate its molecular response mechanism through transcriptomic and physiological indicators. To achieve this, S. alba seedlings were treated with different concentrations of CdCl2 (0.25 mmol/L, 0.5 mmol/L, and 1.0 mmol/L) for three days. Based on seedling performance, S. alba exhibited some tolerance to a low concentration of Cd stress (0.25 mmol/L CdCl2) and a strong Cd accumulation ability in its roots. The activities and contents of several antioxidant enzymes generally exhibited an increase under the treatment of 0.25 mmol/L CdCl2 but decreased under the treatment of higher CdCl2 concentrations. In particular, the proline (Pro) content was extremely elevated under the 0.25 and 0.5 mmol/L CdCl2 treatments but sharply declined under the 1.0 mmol/L CdCl2 treatment, suggesting that Pro is involved in the tolerance of S. alba to low concentration of Cd stress. In addition, RNA sequencing was utilized to analyze the gene expression profiles of S. alba exposed to Cd (under the treatment of 0.25 mmol/L CdCl2). The results indicate that roots were more susceptible to disturbance from Cd stress, as evidenced by the detection of 542 differentially expressed genes (DEGs) in roots compared to only 37 DEGs in leaves. GO and KEGG analyses found that the DEGs induced by Cd stress were primarily enriched in metabolic pathways, plant hormone signal transduction, and the biosynthesis of secondary metabolites. The key pathway hub genes were mainly associated with intracellular ion transport and cell wall synthesis. These findings suggest that S. alba is tolerant to a degree of Cd stress, but is also susceptible to the toxic effects of Cd. Furthermore, these results provide a theoretical basis for understanding Cd tolerance in S. alba. [ABSTRACT FROM AUTHOR]

Trisomy harbouring an extra copy of the chromosome generally causes a variety of physical and intellectual disabilities in mammals but is an extremely rare and important genetic stock in plants. In this study, a spontaneous trisomy plant in a Chinese kale accession (Brassica oleracea var. alboglabra, CC, 2n = 18) that showed significantly smaller plant architecture when compared to other normal plants was found and subsequently confirmed by cytological analysis in which the chromosome set of 2n = 19 and abnormal chromosome behaviour were observed. Then, based on the gene expression deviation determined by RNA-seq, the extra chromosome copy in this trisomy was identified as chromosome C2 (TC2). Compared to normal plants, TC2 not only showed generally upregulated differentially expressed genes (DEGs) on chromosome C2 (97.21% of 573 DEGs in chromosome C2) but also exhibited a whole-genome expression perturbation, in which 1329 DEGs (69.87% of total DEGs) were observed along two-copy chromosomes (trans-effect). The genes in the high (gene expression value > 100) and medium (100 > gene expression value > 10) groups were more prone to decreased gene expression, but the genes in the low group (10 > gene expression value > 0.1) showed upregulated expression deviation. In addition, GO (Gene ontology) annotation analysis revealed that the upregulated DEGs in the trans-effect group were overrepresented by the genes involved in the response to stress category, while the downregulated DEGs in the trans-effect group were mostly enriched in pathways related to DNA synthesis. In conclusion, we think our results can provide important resources for genetic analysis in B. oleracea and show some novel insights for understanding trisomy plant biology. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the impact of modified SiO2 nanoparticles on the mechanical properties of Polymethyl methacrylate (PMMA) composites through a combination of molecular dynamics simulation and experimentation. Our investigation focuses on analyzing the elastic modulus, bulk modulus, shear modulus, and Cauchy ratio of pure PMMA, PMMA/SiO2 composites, and PMMA/modified SiO2 composites over a temperature range of 200–400 K. Our results indicate that, as the temperature increases, the elastic modulus, bulk modulus, and Cauchy ratio of all materials decrease, while the shear modulus initially increases and then decreases. Notably, at room temperature, the elastic modulus, bulk modulus, and shear modulus of the composites increase with an increase in the degree of nanoparticle modification, while the Cauchy ratio exhibits the opposite trend. Our findings suggest that modified SiO2 nanoparticles have the potential to enhance the mechanical properties of composite materials. To validate our simulation results, we also conducted experiments that demonstrated the rationality of our approach. [ABSTRACT FROM AUTHOR]