Polysaccharides from pineapple peel: Structural characterization, film-forming properties and its effect on strawberry preservation.

The growing demand for food safety has stimulated the development of new environmentally friendly food packaging. It is the development trend of food packaging in recent years by using natural polysaccharides as carriers and adding bioactive ingredients extracted from plants to prepare multifunctional films with antioxidant, antimicrobial and biodegradable properties. Herein, three polysaccharide components (PPE40, PPE60, and PPE80) from pineapple peel were extracted by ultrasound-assisted hot water extraction combined with gradient ethanol precipitation method, which all showed a certain scavenging activities against DPPH, ABTS, and hydroxyl radical. Then, the composite films were prepared by adding PPE40, PPE60 and PPE80 to chitosan. The results of SEM, FT-IR and XRD analysis showed that PPE40, PPE60 and PPE80 could interact with chitosan matrix. Furthermore, the addition of PPE40, PPE60, and PPE80 could improve the mechanical properties of the films, and promote the antibacterial activity of the films against B. subtilis, S. aureus and E. coli. Finally, the application of the composite films to strawberries showed that the addition of PPE40, PPE60 and PPE80 could delay the rapid decay of strawberries during storage. The results of this study showed that pineapple polysaccharides have a potential to be applied in the field of food packaging.

A human activity recognition method based on Vision Transformer.

Human activity recognition has a wide range of applications in various fields, such as video surveillance, virtual reality and human-computer intelligent interaction. It has emerged as a significant research area in computer vision. GCN (Graph Convolutional networks) have recently been widely used in these fields and have made great performance. However, there are still some challenges including over-smoothing problem caused by stack graph convolutions and deficient semantics correlation to capture the large movements between time sequences. Vision Transformer (ViT) is utilized in many 2D and 3D image fields and has surprised results. In our work, we propose a novel human activity recognition method based on ViT (HAR-ViT). We integrate enhanced AGCL (eAGCL) in 2s-AGCN to ViT to make it process spatio-temporal data (3D skeleton) and make full use of spatial features. The position encoder module orders the non-sequenced information while the transformer encoder efficiently compresses sequence data features to enhance calculation speed. Human activity recognition is accomplished through multi-layer perceptron (MLP) classifier. Experimental results demonstrate that the proposed method achieves SOTA performance on three extensively used datasets, NTU RGB+D 60, NTU RGB+D 120 and Kinetics-Skeleton 400.

Antiparasitic efficacy of flavonoids identified from Psoralea corylifolia against Tetrahymena piriformis in guppy (Poecilia reticulate).

Tetrahymena piriformis belongs to the ciliated protists (ciliates), causing severe economic losses in aquaculture. Chemical drugs currently used usually have toxic side effects, and there is no specific drug against Tetrahymena. Therefore, it is an urgent need to identify new antiparasitic lead compounds. In the present study, the in vitro parasiticidal activity of ethyl acetate (EtOAc) extracts and water extracts from 22 selected traditional Chinese medicines (TCMs) were evaluated against T. piriformis. The EtOAc extract of P. corylifolia turned out to be the most active with the minimum parasiticidal concentration of 100 mg/L within 3 h. Thus, it was separated into 12 fractions by the first-dimensional (D1) normal phase liquid chromatography (NPLC), meanwhile combining with in vitro antiparasitic tests for activity tracking. Subsequently, 8 flavonoids were identified in the active fractions by the second-dimensional (D2) reverse phase liquid chromatography (RPLC) tandem high-resolution mass spectrometry. According to the results, 5 flavonoids were selected for in vitro antiparasitic test, of which isobavachalcone showed the minimum parasiticidal concentration of 3.125 mg/L in 2 h. Bathing treatment of infected guppies with isobavachalcone could significantly reduce the burden of T. piriformis, obtaining a 24-h median effective concentration (24-h EC50) value of 1.916 mg/L. And the concentration of isobavachalcone causing guppies to die within 24 h is 39 times than that of 24-h EC50. The results demonstrated that isobavachalcone has the potential to be developed into a novel commercial fish drug against T. piriformis.

Meta-adaptive-weighting-based bilateral multi-dimensional refined space feature attention network for imbalanced breast cancer histopathological image classification.

Breast cancer histopathological image automatic classification can reduce pathologists workload and provide accurate diagnosis. However, one challenge is that empirical datasets are usually imbalanced, resulting in poorer classification quality compared with conventional methods based on balanced datasets. The recently proposed bilateral branch network (BBN) tackles this problem through considering both representation and classifier learning to improve classification performance. We firstly apply bilateral sampling strategy to imbalanced breast cancer histopathological image classification and propose a meta-adaptive-weighting-based bilateral multi-dimensional refined space feature attention network (MAW-BMRSFAN). The model is composed of BMRSFAN and MAWN. Specifically, the refined space feature attention module (RSFAM) is based on convolutional long short-term memories (ConvLSTMs). It is designed to extract refined spatial features of different dimensions for image classification and is inserted into different layers of classification model. Meanwhile, the MAWN is proposed to model the mapping from a balanced meta-dataset to imbalanced dataset. It finds suitable weighting parameter for BMRSFAN more flexibly through adaptively learning from a small amount of balanced dataset directly. The experiments show that MAW-BMRSFAN performs better than previous methods. The recognition accuracy of MAW-BMRSFAN under four different magnifications still is higher than 80% even when unbalance factor is 16, indicating that MAW-BMRSFAN can make ideal performance under extreme imbalanced conditions.

Improved Robot Path Planning Method Based on Deep Reinforcement Learning.

With the advancement of robotics, the field of path planning is currently experiencing a period of prosperity. Researchers strive to address this nonlinear problem and have achieved remarkable results through the implementation of the Deep Reinforcement Learning (DRL) algorithm DQN (Deep Q-Network). However, persistent challenges remain, including the curse of dimensionality, difficulties of model convergence and sparsity in rewards. To tackle these problems, this paper proposes an enhanced DDQN (Double DQN) path planning approach, in which the information after dimensionality reduction is fed into a two-branch network that incorporates expert knowledge and an optimized reward function to guide the training process. The data generated during the training phase are initially discretized into corresponding low-dimensional spaces. An "expert experience" module is introduced to facilitate the model's early-stage training acceleration in the Epsilon-Greedy algorithm. To tackle navigation and obstacle avoidance separately, a dual-branch network structure is presented. We further optimize the reward function enabling intelligent agents to receive prompt feedback from the environment after performing each action. Experiments conducted in both virtual and real-world environments have demonstrated that the enhanced algorithm can accelerate model convergence, improve training stability and generate a smooth, shorter and collision-free path.

Breast cancer histopathological images classification based on deep semantic features and gray level co-occurrence matrix.

Breast cancer is regarded as the leading killer of women today. The early diagnosis and treatment of breast cancer is the key to improving the survival rate of patients. A method of breast cancer histopathological images recognition based on deep semantic features and gray level co-occurrence matrix (GLCM) features is proposed in this paper. Taking the pre-trained DenseNet201 as the basic model, part of the convolutional layer features of the last dense block are extracted as the deep semantic features, which are then fused with the three-channel GLCM features, and the support vector machine (SVM) is used for classification. For the BreaKHis dataset, we explore the classification problems of magnification specific binary (MSB) classification and magnification independent binary (MIB) classification, and compared the performance with the seven baseline models of AlexNet, VGG16, ResNet50, GoogLeNet, DenseNet201, SqueezeNet and Inception-ResNet-V2. The experimental results show that the method proposed in this paper performs better than the pre-trained baseline models in MSB and MIB classification problems. The highest image-level recognition accuracy of 40×, 100×, 200×, 400× is 96.75%, 95.21%, 96.57%, and 93.15%, respectively. And the highest patient-level recognition accuracy of the four magnifications is 96.33%, 95.26%, 96.09%, and 92.99%, respectively. The image-level and patient-level recognition accuracy for MIB classification is 95.56% and 95.54%, respectively. In addition, the recognition accuracy of the method in this paper is comparable to some state-of-the-art methods.

Regional level influenza study based on Twitter and machine learning method.

The significance of flu prediction is that the appropriate preventive and control measures can be taken by relevant departments after assessing predicted data; thus, morbidity and mortality can be reduced. In this paper, three flu prediction models, based on twitter and US Centers for Disease Control's (CDC's) Influenza-Like Illness (ILI) data, are proposed (models 1-3) to verify the factors that affect the spread of the flu. In this work, an Improved Particle Swarm Optimization algorithm to optimize the parameters of Support Vector Regression (IPSO-SVR) was proposed. The IPSO-SVR was trained by the independent and dependent variables of the three models (models 1-3) as input and output. The trained IPSO-SVR method was used to predict the regional unweighted percentage ILI (%ILI) events in the US. The prediction results of each model are analyzed and compared. The results show that the IPSO-SVR method (model 3) demonstrates excellent performance in real-time prediction of ILIs, and further highlights the benefits of using real-time twitter data, thus providing an effective means for the prevention and control of flu.