MotionBEV: Attention-Aware Online LiDAR Moving Object Segmentation with Bird's Eye View based Appearance and Motion Features

Identifying moving objects is an essential capability for autonomous systems, as it provides critical information for pose estimation, navigation, collision avoidance, and static map construction. In this paper, we present MotionBEV, a fast and accurate framework for LiDAR moving object segmentation, which segments moving objects with appearance and motion features in the bird's eye view (BEV) domain. Our approach converts 3D LiDAR scans into a 2D polar BEV representation to improve computational efficiency. Specifically, we learn appearance features with a simplified PointNet and compute motion features through the height differences of consecutive frames of point clouds projected onto vertical columns in the polar BEV coordinate system. We employ a dual-branch network bridged by the Appearance-Motion Co-attention Module (AMCM) to adaptively fuse the spatio-temporal information from appearance and motion features. Our approach achieves state-of-the-art performance on the SemanticKITTI-MOS benchmark. Furthermore, to demonstrate the practical effectiveness of our method, we provide a LiDAR-MOS dataset recorded by a solid-state LiDAR, which features non-repetitive scanning patterns and a small field of view

Chemotherapy-Induced Ca2+ Release Stimulates Breast Cancer Stem Cell Enrichment

Breast cancer stem cells (BCSCs) play a critical role in tumor recurrence and metastasis. Exposure of breast cancer cells to chemotherapy leads to an enrichment of BCSCs. Here, we find that chemotherapy induces the expression of glutathione S-transferase omega 1 (GSTO1), which is dependent on hypoxia-inducible factor 1 (HIF-1) and HIF-2. Knockdown of GSTO1 expression abrogates carboplatin-induced BCSC enrichment, decreases tumor initiation and metastatic capacity, and delays tumor recurrence after chemotherapy. GSTO1 interacts with the ryanodine receptor RYR1 and promotes calcium release from the endoplasmic reticulum. Increased cytosolic calcium levels activate PYK2 → SRC → STAT3 signaling, leading to increased expression of pluripotency factors and BCSC enrichment. HIF inhibition blocks chemotherapy-induced GSTO1 expression and BCSC enrichment. Combining HIF inhibitors with chemotherapy may improve clinical outcome in breast cancer

Prediction of Novel High-Pressure Structures of Magnesium Niobium Dihydride

On the basis of a combination of the particle-swarm optimization technique and density functional theory (DFT), we explore the crystal structures of MgH₂, NbH₂, and MgNbH₂ under high pressure. The enthalpy–pressure (<i>H</i>–<i>P</i>) diagrams indicate that the structural transition sequence of MgH₂ is α → γ → δ → ε → ζ and that NbH₂ transforms from the <i>Fm</i>3̅<i>m</i> phase to the <i>Pnma</i> phase at 47.80 GPa. However, MgNbH₂ is unstable when the pressure is too low or too high. Two novel MgNbH₂ structures, the hexagonal <i>P</i>6̅<i>m</i>2 phase and the orthorhombic <i>Cmcm</i> phase, are discovered, which are stable in the pressure ranges of 13.24–128.27 GPa and 128.27–186.77 GPa, respectively. The <i>P</i>6̅<i>m</i>2 phase of MgNbH₂ consists of alternate layers of polymetric NbH₆ and MgH₆ triangular prisms, while the <i>Cmcm</i> phase contains distorted MgH₆ trigonal prisms. The calculated elastic constants and phonon dispersions confirm that both phases are mechanically and dynamically stable. The analyses of density of states (DOS), electron localization function (ELF), and Bader charge demonstrate that a combination of ionic and metallic bonds exist in both <i>P</i>6̅<i>m</i>2 and <i>Cmcm</i> phases. We hope the newly predicted magnesium niobium dihydrides with desirable electronic properties will promote future experimental and theoretical studies on mixed main group-transition metal hydrides

Prediction of Stable Ruthenium Silicides from First-Principles Calculations: Stoichiometries, Crystal Structures, and Physical Properties

We present results of an unbiased structure search for stable ruthenium silicide compounds with various stoichiometries, using a recently developed technique that combines particle swarm optimization algorithms with first-principles calculations. Two experimentally observed structures of ruthenium silicides, RuSi (space group <i>P</i>2₁3) and Ru₂Si₃ (space group <i>Pbcn</i>), are successfully reproduced under ambient pressure conditions. In addition, a stable RuSi₂ compound with β-FeSi₂ structure type (space group <i>Cmca</i>) was found. The calculations of the formation enthalpy, elastic constants, and phonon dispersions demonstrate the <i>Cmca</i>-RuSi₂ compound is energetically, mechanically, and dynamically stable. The analysis of electronic band structures and densities of state reveals that the <i>Cmca</i>-RuSi₂ phase is a semiconductor with a direct band gap of 0.480 eV and is stabilized by strong covalent bonding between Ru and neighboring Si atoms. On the basis of the Mulliken overlap population analysis, the Vickers hardness of the <i>Cmca</i> structure RuSi₂ is estimated to be 28.0 GPa, indicating its ultra-incompressible nature

Ab Initio Search for Global Minimum Structures of Pure and Boron Doped Silver Clusters

The global minimum structures of pure and boron doped silver clusters up to 16 atoms are determined through ab initio calculations and unbiased structure searching methods. The structural and electronic properties of neutral, anionic, and cationic Ag_<i>n</i>B (<i>n</i> ≤ 15) and Ag_<i>n</i>B₂ (<i>n</i> ≤ 14) clusters are much distinct from those of the corresponding pure silver. Considering that Ag and B possess one and three valence electrons, respectively, both the single and the double boron-atom doped silver clusters with even number of valence electrons are more stable than those with odd number of electrons, a feature also observed in the pure silver clusters. We demonstrate that the species with a valence count of 8 and 14 appear to be magic numbers with enhanced stability irrespective of component or the charged state. A new putative global minimum structure of Ag₁₃^– cluster, with high symmetry of <i>C</i>_2<i>v</i>, is unexpectedly observed as the ground state, which is lower in energy than the previous suggested bilayer structure