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Grading tea leaves efficiently in a natural environment is a crucial technological foundation for the automation of tea-picking robots. In this study, to solve the problems of dense distribution, limited feature-extraction ability, and false detection in the field of tea grading recognition, an improved YOLOv8n model for tea grading and counting recognition was proposed. Firstly, the SPD-Conv module was embedded into the backbone of the network model to enhance the deep feature-extraction ability of the target. Secondly, the Super-Token Vision Transformer was integrated to reduce the model's attention to redundant information, thus improving its perception ability for tea. Subsequently, the loss function was improved to MPDIoU, which accelerated the convergence speed and optimized the performance. Finally, a classification-positioning counting function was added to achieve the purpose of classification counting. The experimental results showed that, compared to the original model, the precision, recall and average precision improved by 17.6%, 19.3%, and 18.7%, respectively. The average precision of single bud, one bud with one leaf, and one bud with two leaves were 88.5%, 89.5% and 89.1%. In this study, the improved model demonstrated strong robustness and proved suitable for tea grading and edge-picking equipment, laying a solid foundation for the mechanization of the tea industry. [ABSTRACT FROM AUTHOR]

The 6-DOF Stewart parallel elevation platform serves as the platform for mounting the tea-picking robotic arm, significantly impacting the operational scope, velocity, and harvesting precision of the robotic arm. Utilizing the Stewart setup, a parallel elevation platform with automated lifting and leveling capabilities was devised, ensuring precise halts at designated elevations for seamless harvesting operations. The effectiveness of the platform parameter configuration and the reasonableness of the posture changes were verified. Firstly, the planting mode and growth characteristics of Yunnan large-leaf tea trees were analyzed to determine the preset path, posture changes, and mechanism stroke of the Stewart parallel lifting platform, thereby determining the basic design specifications of the platform. Secondly, a 3D model was established using SolidWorks, a robust adaptive PD control model was built using MATLAB for simulation, and dynamic calculations were carried out through data interaction in Simulink and ADAMS. Finally, the rationality of the lifting platform design requirements was determined based on simulation data, a 6-DOF Stewart parallel lifting platform was manufactured, and a motion control system was built for experimental verification according to the design specifications and simulation data. The results showed that the maximum deviation angle around the X, Y, and Z axes was 10°, the maximum lifting distance was 15 cm, the maximum load capacity was 60 kg, the platform response error was within ±0.1 mm, and the stable motion characteristics reached below the millimeter level, which can meet the requirements of automated operation of the auxiliary picking robotic arm. [ABSTRACT FROM AUTHOR]

The generation of a tau-V337M point mutation mouse model using gene editing technology can provide an animal model with fast disease progression and more severe symptoms, which facilitate the study of pathogenesis and treatment of Alzheimer's disease (AD). In this study, single guide RNAs (sgRNA) and single-stranded oligonucleotides (ssODN) were designed and synthesized in vitro . The mixture of sgRNA, Cas9 protein and ssODN was microinjected into the zygotes of C57BL/6J mice. After DNA cutting and recombination, the site homologous to human 337 valine (GTG) in exon 11 was mutated into methionine (ATG). In order to improve the efficiency of recombination, a Rad51 protein was added. The female mice mated with the nonvasectomy male mice were used as the surrogates. Subsequently, the 2-cell stage gene edited embryos were transferred into the unilateral oviduct, and the F0 tau-V337M mutation mice were obtained. Higher mutation efficiency could be obtained by adding Rad51 protein. The F0 tau-V337M point mutation mice can pass the mutation on to the F1 generation mice. In conclusion, this study successfully established the first tau-V337M mutation mouse by using Cas9, ssODN and Rad51. These results provide a new method for developing AD mice model which can be used in further research on the pathogenesis and treatment of AD.

Background: Distinguishing bacterial infections from viral infections is very important for accurate and appro-priate drug treatment, alleviating diseases and avoiding side effects caused by drug abuse. The aim of this study is to assess the clinical usefulness of the lymphocyte VCS (volume, conductivity, light scatter) parameters to dis-tinguish bacterial infection from viral infection., Methods: Peripheral blood was collected from 60 viral infection patients (VIG), 63 bacterial infection patients (BIG), and 95 healthy controls (HC). The lymphocyte VCS parameters and blood routine indicators were obtained by using a hematology analyzer with VCS technology. The critical cutoff value, sensitivity and specificity were established based on receiver operator characteristic (ROC) curve analysis., Results: Mean volume of lymphocytes (MV-LY), median angle light scatter of lymphocytes (MALS-LY), upper median angle light scatter of lymphocytes (UMALS-LY), neutrophil-lymphocyte ratio (NLR) were significantly increased in the bacterial infection group compared with the viral infection group and the healthy controls. The area under curve (AUC) for mean volume of lymphocytes (MV-LY) was 0.8143 for discriminating the bacterial infection group from the viral infection group. For median angle light scatter of lymphocytes (MALS-LY), the area under curve (AUC) was 0.8116. For upper median angle light scatter of lymphocytes (UMALS-LY), the area under curve (AUC) was 0.8631. For neutrophil-lymphocyte ratio (NLR), the area under curve (AUC) was 0.8513., Conclusions: This study clarifies that mean volume of lymphocytes, median angle light scatter of lymphocytes, and upper median angle light scatter of lymphocytes have good clinical practical value in distinguishing bacterial infection from viral infection and healthy controls because of its high sensitivity and specificity.