SemanticLoop: loop closure with 3D semantic graph matching

Loop closure can effectively correct the accumulated error in robot localization, which plays a critical role in the long-term navigation of the robot. Traditional appearance-based methods rely on local features and are prone to failure in ambiguous environments. On the other hand, object recognition can infer objects' category, pose, and extent. These objects can serve as stable semantic landmarks for viewpoint-independent and non-ambiguous loop closure. However, there is a critical object-level data association problem due to the lack of efficient and robust algorithms. We introduce a novel object-level data association algorithm, which incorporates IoU, instance-level embedding, and detection uncertainty, formulated as a linear assignment problem. Then, we model the objects as TSDF volumes and represent the environment as a 3D graph with semantics and topology. Next, we propose a graph matching-based loop detection based on the reconstructed 3D semantic graphs and correct the accumulated error by aligning the matched objects. Finally, we refine the object poses and camera trajectory in an object-level pose graph optimization. Experimental results show that the proposed object-level data association method significantly outperforms the commonly used nearest-neighbor method in accuracy. Our graph matching-based loop closure is more robust to environmental appearance changes than existing appearance-based methods

The influence of 1-MCP on the fruit quality and flesh browning of ‘Red Fuji’ apple after long-term cold storage

This study assessed the influence of 1-MCP treatment on the fruit quality and flesh browning of ‘Red Fuji’ apple at shelf life after long-term cold storage. The ‘Red Fuji’ fruit were stored at 0±0.5 °C for 270 days after treating with 1.0 μL L-1 1-methylcyclopropylene (1-MCP). Fruit quality, browning rate of stem-end flesh, chlorogenic acid content, polyphenol oxidase (PPO) activity were analyzed at shelf-life under 20±0.5 °C, the expression profile of ethylene receptors (MdERS1), phenylalnine ammonia lyase genes (MdPA L1, MdPA L2), quinate hydroxycinnamoyl/hydrxycinnamoyl CoA shi-kimate gene (MdHCT3), polyphenol oxidase genes (MdPPO1, MdPPO5)and lipoxygenase gene (MdLOX) were measured by real-time quantitative PCR. 1-MCP treatment improved the fruit storage quality, decreased stem-end flesh tissue browning, and fruit decay. In addition, the fruit respiration rate and ethylene production rate increased at shelf-life, but this increase could be inhibited by 1-MCP. The same rule was observed in the changes of chlorogenic acid content and PPO activity, the expression of MdERS1, MdPA L1, MdPPO1 and MdLOX were inhibited by 1-MCP as well in the stem-end flesh. Thus, 1-MCP treatment improves the fruit quality of ‘Red Fuji’ apple at shelf-life after long-term cold storage, and inhibits the browning of stem-end flesh by decreasing the chlorogenic acid content and PPO activity. MdPA L1, MdHCT3, MdPPO1 and MdLOX participate in the flesh browning progress

Efficient 5 '-3 ' DNA end resection by HerA and NurA is essential for cell viability in the crenarchaeon <i>Sulfolobus islandicus</i>

BACKGROUND: ATPase/Helicases and nucleases play important roles in homologous recombination repair (HRR). Many of the mechanistic details relating to these enzymes and their function in this fundamental and complicated DNA repair process remain poorly understood in archaea. Here we employed Sulfolobus islandicus, a hyperthermophilic archaeon, as a model to investigate the in vivo functions of the ATPase/helicase HerA, the nuclease NurA, and their associated proteins Mre11 and Rad50. RESULTS: We revealed that each of the four genes in the same operon, mre11, rad50, herA, and nurA, are essential for cell viability by a mutant propagation assay. A genetic complementation assay with mutant proteins was combined with biochemical characterization demonstrating that the ATPase activity of HerA, the interaction between HerA and NurA, and the efficient 5′-3′ DNA end resection activity of the HerA-NurA complex are essential for cell viability. NurA and two other putative HRR proteins: a PIN (PilT N-terminal)-domain containing ATPase and the Holliday junction resolvase Hjc, were co-purified with a chromosomally encoded N-His-HerA in vivo. The interactions of HerA with the ATPase and Hjc were further confirmed by in vitro pull down. CONCLUSION: Efficient 5′-3′ DNA end resection activity of the HerA-NurA complex contributes to necessity of HerA and NurA in Sulfolobus, which is crucial to yield a 3′-overhang in HRR. HerA may have additional binding partners in cells besides NurA. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12867-015-0030-z) contains supplementary material, which is available to authorized users

Phase Transformation of Coal Ash under Biochemical Condition and Its Significance

China University of GeosciencesPromoting Environmental Pesearch in Pan-Japan Sea Area : Young Researchers\u27 Network, Schedule: March 8-10,2006,Kanazawa Excel Hotel Tokyu, Japan, Organized by: Kanazawa University 21st-Century COE Program, Environmental Monitoring and Prediction of Long- & Short- Term Dynamics of Pan-Japan Sea Area ; IICRC(Ishikawa International Cooperation Research Centre), Sponsors : Japan Sea Research ; UNU-IAS(United Nations University Institute of Advanced Studies)+Ishikawa Prefecture Government ; City of Kanazaw

Molecular Dynamic Simulation to Explore the Molecular Basis of Btk-PH Domain Interaction with Ins(1,3,4,5)P4

Bruton’s tyrosine kinase contains a pleckstrin homology domain, and it specifically binds inositol 1,3,4,5-tetrakisphosphate (Ins(1,3,4,5)P4), which is involved in the maturation of B cells. In this paper, we studied 12 systems including the wild type and 11 mutants, K12R, S14F, K19E, R28C/H, E41K, L11P, F25S, Y40N, and K12R-R28C/H, to investigate any change in the ligand binding site of each mutant. Molecular dynamics simulations combined with the method of molecular mechanics/Poisson-Boltzmann solvent-accessible surface area have been applied to the twelve systems, and reasonable mutant structures and their binding free energies have been obtained as criteria in the final classification. As a result, five structures, K12R, K19E, R28C/H, and E41K mutants, were classified as “functional mutations,” whereas L11P, S14F, F25S, and Y40N were grouped into “folding mutations.” This rigorous study of the binding affinity of each of the mutants and their classification provides some new insights into the biological function of the Btk-PH domain and related mutation-causing diseases

Quintic trigonometric Bézier curve with two shape parameters

The fifth degree of trigonometric Bézier curve called quintic with two shapes parameter is presented in this paper. Shape parameters provide more control on the shape of the curve compared to the ordinary Bézier curve. This technique is one of the crucial parts in constructing curves and surfaces because the presence of shape parameters will allow the curve to be more flexible without changing its control points. Furthermore, by changing the value of shape parameters, the curve still preserves its geometrical features thus makes it more convenient rather than altering the control points. But, to interpolate curves from one point to another or surface patches, we need to satisfy certain continuity constraints to ensure the smoothness not just parametrically but also geometrically