Visual loop closure detection, which can be considered as an image retrieval task, is an important problem in SLAM (Simultaneous Localization and Mapping) systems. The frequently used bag-of-words (BoW) models can achieve high precision and moderate recall. However, the requirement for lower time costs and fewer memory costs for mobile robot applications is not well satisfied. In this paper, we propose a novel loop closure detection framework titled 'FILD' (Fast and Incremental Loop closure Detection), which focuses on an on-line and incremental graph vocabulary construction for fast loop closure detection. The global and local features of frames are extracted using the Convolutional Neural Networks (CNN) and SURF on the GPU, which guarantee extremely fast extraction speeds. The graph vocabulary construction is based on one type of proximity graph, named Hierarchical Navigable Small World (HNSW) graphs, which is modified to adapt to this specific application. In addition, this process is coupled with a novel strategy for real-time geometrical verification, which only keeps binary hash codes and significantly saves on memory usage. Extensive experiments on several publicly available datasets show that the proposed approach can achieve fairly good recall at 100% precision compared to other stateof-the-art methods. The source code can be downloaded at https://github.com/AnshanTJU/FILD for further studies.

Adsorption separation of linear and branched alkane isomers provides an energy-saving alternative way to improve the octane number of gasoline compared to distillation, while zeolite 5A is nearly the only commercialized adsorbent for this process. Although metal−organic frameworks are widely considered to be more promising than traditional zeolites owing to their designability and tunability, the industrial application is hindered by their low stability, high cost, or other issues. Herein, using readily available biobased L-aspartic acid as a ligand, a sustainable and low-cost microporous material, termed as Ni-Asp, is constructed and proved to be effective for recognition and adsorption separation of n-hexane from its branched isomers. The appropriate rectangular pore with uniformly distributed Osites from monodentate carboxyl groups along the channel endows Ni-Asp with strong affinity toward n-hexane, while excluding branched isomers, which is discussed in detail by DFT calculations and verified by column breakthrough experiments. In addition, intraframework hydrogen bonds between the ammino and carboxyl groups of L-Asp further stabilize the coordination network, making Ni-Asp an ultrastable MOF. Considering the environment-friendly aqueous growing conditions, Ni-Asp shows a great potential in the adsorption application for hexane isomer separation.

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With changes in lifestyle and an increase in bad health habits, cancer has become a noncommunicable and frequently occurring disease that poses a serious threat to human life. Cancer is associated with high rates of morbidity and mortality worldwide. As a major negative life event, advanced malignancies lead to strong mood swings in most patients. Furthermore, various internal and external factors can have a huge impact on patients’ physical and mental health and put them in a stressful situation, causing a series of psychological stress responses. To explore the degree of fear of disease progression in patients with advanced cancer and the usefulness of dignity therapy. Overall, 120 patients with advanced malignant tumors admitted to Shijiazhuang No. 1 hospital between January 2019 and January 2020 were enrolled. The selected patients were divided into the test and control groups (60 people per group) using a random number table. All patients received basic treatment. Patients in the trial group also received dignity therapy. The intervention period was 4 weeks. Simplified scales were used for assessing disease progression (FoP-Q-SF) and quality of life (QLQ-C30) before and after the intervention, and the scores were compared between the groups. After the intervention, the degree of fear in the experimental group was lower than that of the control group. Cognitive function, emotional function, and the scores of the overall health status of the experimental group were higher than those of the control group. Additionally, the scores of fatigue, insomnia, loss of appetite, and diarrhea in the experimental group were lower than those of the control group ( P  < 0.05). The social support level scale scores, depression scores, hospital anxiety and depression scale scores, and patient dignity inventory scores of the experimental group were lower than those of the control group ( P  < 0.05). Patients with advanced malignant tumors have fear, anxiety, and depression related to disease progression. Dignity therapy is useful for improving the patients’ quality of life, increasing dignity, and enhancing social support.

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