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High-definition digital map is the foundation of autonomous driving technology, which provides precise location information for autonomous vehicles. However, with the change of environment and the passage of time, the fidelity performance of unstructured road map will gradually decline. Therefore, this paper proposes a digital map updating method of open-pit mine based on vehicle-cloud collaboration to effectively improve the efficiency of map updating. Firstly, a three-layer map model structure is constructed to ensure the integrity of map updating of open-pit mine. Then, a track-based map updating method is proposed for many scenarios of open-pit mines. Meanwhile, a map updating framework based on vehicle-cloud collaboration is designed to improve the efficiency of automatic driving map updating in open-pit mines. Experimental results show that this method can effectively reduce the map updating delay. Compared with the single-vehicle mode, the average map updating delay is reduced by 75%. At the same time, the relative error of map updating is reduced, and the overall accuracy is increased by 10%, which meets the requirements of map fidelity.

Clear understanding of the relationship between electronic structure and chemical activity will aid in the rational design of nanocatalysts. Core-shell Au-coated dysprosium and yttrium disilicide nanowires provide a model atomic scale system to understand how charges that transfer across interfaces affect other electronic properties and in turn surface activities toward adsorbates. Scanning tunneling microscopy data demonstrate self-organized growth of Au-coated DySi₂ nanowires with a nanometer feature size on Si(001), and Kelvin probe force microscopy data measure a reduction of work function that is explained in terms of charge transfer. Density functional theory calculations predict the preferential adsorption site and segregation path of Au adatoms on Si(001) and YSi₂. The chemical properties of Au-YSi₂ nanowires are then discussed in light of charge density, density of states, and adsorption energy of CO molecules.

The adsorption patterns of rare earth atoms on Si(001) were investigated using scanning tunneling microscopy measurements and density functional calculations. Stable configurations were systematically determined via calculation of binding energies of various adatom coverage and adsorption geometry. Competition between inter-adatom hybridization and Coulomb repulsion is the mechanism contributing to binding energy minima associated with commonly observed rare earth adsorption geometries. Comparison of stable configurations with experimental scanning tunneling microscopy images demonstrated accuracy of the theoretical models. This paves a way for the understanding of self-assembly of rare earth disilicide nanowires on vicinal Si(001) substrates. © 2009 Elsevier B.V. All rights reserved.

Background: Hematopoietic stem cells (HSCs) from different sources show varied repopulating capacity, and HSCs lose their stemness after long‐time ex vivo culture. A deep understanding of these phenomena may provide helpful insights for HSCs. Methods: Here, we applied single‐cell RNA‐seq (scRNA‐seq) to analyse the naïve and stimulated human CD34+ cells from cord blood (CB) and mobilised peripheral blood (mPB). Results: We collected over 16 000 high‐quality single‐cell data to construct a comprehensive inference map and characterised the HSCs under a quiescent state on the hierarchy top. Then, we compared HSCs in CB with those in mPB and HSCs of naïve samples to those of cultured samples, and identified stemness‐related genes (SRGs) associated with cell source (CS‐SRGs) and culture time (CT‐SRGs), respectively. Interestingly, CS‐SRGs and CT‐SRGs share genes enriched in the signalling pathways such as mRNA catabolic process, translational initiation, ribonucleoprotein complex biogenesis and cotranslational protein targeting to membrane, suggesting dynamic protein translation and processing may be a common requirement for stemness maintenance. Meanwhile, CT‐SRGs are enriched in pathways involved in glucocorticoid and corticosteroid response that affect HSCs homing and engraftment. In contrast, CS‐SRGs specifically contain genes related to purine and ATP metabolic process, which is crucial for HSC homeostasis in the stress settings. Particularly, when CT‐SRGs are used as reference genes for the construction of the development trajectory of CD34+ cells, lymphoid and myeloid lineages are clearly separated after HSCs/MPPs. Finally, we presented an application through a small‐scale drug screening using Connectivity Map (CMap) against CT‐SRGs. A small molecule, cucurbitacin I, was found to efficiently expand HSCs ex vivo while maintaining its stemness. Conclusions: Our findings provide new perspectives for understanding HSCs, and the strategy to identify candidate molecules through SRGs may be applicable to study other stem cells. [ABSTRACT FROM AUTHOR]

β-thalassemia, caused by mutations in the human hemoglobin β ( HBB ) gene, is one of the most common genetic diseases in the world. The HBB -28(A>G) mutation is one of the five most common mutations in Chinese patients with β-thalassemia. However, few studies have been conducted to understand how this mutation affects the expression of pathogenesis-related genes, including globin genes, due to limited homozygote clinical materials. Therefore, we developed an efficient technique using CRISPR/Cas9 combined with asymmetric single-stranded oligodeoxynucleotides (assODNs) to generate a K562 cell model with HBB -28(A>G) named K562 -28(A>G) . Then, we systematically analyzed the differences between K562 -28(A>G) and K562 at the transcriptome level by high-throughput RNA-seq before and after erythroid differentiation. We found that the HBB -28(A>G) mutation not only disturbed the transcription of HBB , but also decreased the expression of HBG , which may further aggravate the thalassemia phenotype and partially explain the more severe clinical outcome of β-thalassemia patients with the HBB -28(A>G) mutation. Moreover, we found that the K562 -28(A>G) cell line is more sensitive to hypoxia and shows a defective erythrogenic program compared with K562 before differentiation. Importantly, all abovementioned abnormalities in K562 -28(A>G) were reversed after correction of this mutation with CRISPR/Cas9 and assODNs, confirming the specificity of these phenotypes. Overall, this is the first time to analyze the effects of the HBB -28(A>G) mutation at the whole-transcriptome level based on isogenic cell lines, providing a landscape for further investigation of the mechanism of β-thalassemia with the HBB -28(A>G) mutation., (Copyright © 2020 Li, Zhou, Sun, Ouyang, Dong, Liu, Ge, Zhang, Liu and Gu.)

Clear understanding of the relationship between electronic structure and chemical activity will aid in the rational design of nanocatalysts. Core-shell Au-coated dysprosium and yttrium disilicide nanowires provide a model atomic scale system to understand how charges that transfer across interfaces affect other electronic properties and in turn surface activities toward adsorbates. Scanning tunneling microscopy data demonstrate self-organized growth of Au-coated DySi₂ nanowires with a nanometer feature size on Si(001), and Kelvin probe force microscopy data measure a reduction of work function that is explained in terms of charge transfer. Density functional theory calculations predict the preferential adsorption site and segregation path of Au adatoms on Si(001) and YSi₂. The chemical properties of Au-YSi₂ nanowires are then discussed in light of charge density, density of states, and adsorption energy of CO molecules.