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Benchmarking visual SLAM methods in mirror environments

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Computational Visual Media 2024年第2期10卷 215-241页

作者： Peter herbert Jing Wu Ze Ji Yu-Kun Lai School of Computer Science and Informatics Cardiff UniversityAbacws BuildingSenghennydd RdCardiff CF244AGUK School of Engineering Cardiff UniversityQueen’s BuildingsThe ParadeCardiff CF243AAUK

Visual simultaneous localisation and mapping(vSLAM)finds applications for indoor and outdoor navigation that routinely subjects it to visual complexities,particularly mirror *** effect of mirror presence(time visible and its average size in the frame)was hypothesised to impact localisation and mapping performance,with systems using direct techniques expected to perform ***,a dataset,MirrEnv,of image sequences recorded in mirror environments,was collected,and used to evaluate the performance of existing representative *** ORB-SLAM3 and BundleFusion appear to show moderate degradation of absolute trajectory error with increasing mirror duration,whilst the remaining results did not show significantly degraded localisation *** mesh maps generated proved to be very inaccurate,with real and virtual reflections colliding in the reconstructions.A discussion is given of the likely sources of error and robustness in mirror environments,outlining future directions for validating and improving vSLAM performance in the presence of planar *** MirrEnv dataset is available at https://***/10.17035/d.2023.0292477898.

关键词： visual simultaneous localisation and mapping(vSLAM) mirror localisation mapping reflection datase

A digital twins enabled underwater intelligent internet vehicle path planning system via reinforcement learning and edge computing

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Digital Communications and Networks 2024年第2期10卷 282-291页

作者： Jiachen Yang Meng Xi Jiabao Wen Yang Li Houbing herbert Song School of Electrical and Information Engineering Tianjin UniversityTianjin300072China Security and Optimization for Networked Globe Laboratory(SONG Lab) Embry-Riddle Aeronautical UniversityDaytona BeachFL32114USA

The Autonomous Underwater Glider(AUG)is a kind of prevailing underwater intelligent internet vehicle and occupies a dominant position in industrial applications,in which path planning is an essential *** to the complexity and variability of the ocean,accurate environment modeling and flexible path planning algorithms are pivotal *** traditional models mainly utilize mathematical functions,which are not complete and *** existing path planning algorithms depend on the environment and lack *** overcome these challenges,we propose a path planning system for underwater intelligent internet *** applies digital twins and sensor data to map the real ocean environment to a virtual digital space,which provides a comprehensive and reliable environment for path *** design a value-based reinforcement learning path planning algorithm and explore the optimal network structure *** path simulation is controlled by a closed-loop model integrated into the terminal vehicle through edge *** integration of state input enriches the learning of neural networks and helps to improve generalization and *** task-related reward function promotes the rapid convergence of the *** experimental results prove that our reinforcement learning based path planning algorithm has great flexibility and can effectively adapt to a variety of different ocean conditions.

关键词： Digital twins Reinforcement learning Edge computing Underwater intelligent internet vehicle Path planning

Potential Secretory Transporters and Biosynthetic Precursors of Biological Nitrification Inhibitor 1,9-Decanediol in Rice as Revealed by Transcriptome and Metabolome Analyses

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Rice science 2024年第1期31卷 87-102页

作者： DI Dongwei MA Mingkun ZHANG Xiaoyang LU Yufang herbert J.KRONZUCKER SHI Weiming State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China School of Food Science and Engineering Foshan UniversityFoshan 528000China School of BioSciences The University of MelbourneParkvilleVIC 3010Australia University of Chinese Academy of Sciences Beijing 100049China

Biological nitrification inhibitors(BNIs)are released from plant roots and inhibit the nitrification activity of microorganisms in soils,reducing NO_(3)^(‒)leaching and N2O emissions,and increasing nitrogenuse efficiency(NUE).Several recent studies have focused on the identification of new BNIs,yet little is known about the genetic loci that govern their biosynthesis and *** applied a combined transcriptomic and metabolomic analysis to investigate possible biosynthetic pathways and transporters involved in the biosynthesis and release of BNI 1,9-decanediol(1,9-D),which was previously identified in rice root *** results linked four fatty acids,icosapentaenoic acid,linoleate,norlinolenic acid,and polyhydroxy-α,ω-divarboxylic acid,with 1,9-D biosynthesis and three transporter families,namely the ATP-binding cassette protein family,the multidrug and toxic compound extrusion family,and the major facilitator superfamily,with 1,9-D release from roots into the soil *** finding provided candidates for further work on the genes implicated in the biosynthesis and secretion of 1,9-D and pinpoint genetic loci for crop breeding to improve NUE by enhancing 1,9-D secretion,with the potential to reduce NO_(3)^(‒)leaching and N2O emissions from agricultural soils.

关键词： 1,9-decanediol biological nitrification inhibitor metabolomic analysis nitrogen-use efficiency transcriptomic analysis

A simulation study on spatial and time resolution for a cost-effective positron emission particle tracking system

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Particuology 2024年第5期88卷 312-322页

作者： Josephine Oppotsch Matthias Steinke Miriam Fritsch Fritz-herbert Heinsius Thomas Held Nikoline Hilse Viktor Scherer Ulrich Wiedner Ruhr-Universität Bochum Institut für Experimentalphysik I44801 BochumGermany Ruhr-Universität Bochum Lehrstuhl für Energieanlagen und Energieprozesstechnik44801 BochumGermany

This work is the second part of a simulation study investigating the processing of densely packed and moving granular assemblies by positron emission particle tracking (PEPT).Since medical positron emission tomography (PET) scanners commonly used for PEPT are very expensive,a PET-like detector system based on cost-effective organic plastic scintillator bars is being developed and tested for its *** this context,the spatial resolution of a resting positron source,a source moving on a freely designed model path,and a particle motion given by a discrete element method (DEM) simulation is studied using Monte Carlo simulations and the software toolkit *** not only extended the simulation and reconstruction to a moving source but also significantly improved the spatial resolution compared to previous work by adding oversampling and iteration to the reconstruction ***,in the case of a source following a trajectory developed from DEM simulations,a very good resolution of about 1 mm in all three directions and an average 3D deviation between simulated and reconstructed events of 2.3 mm could be ***,the resolution for realistic particle motion within the generic grate system (which is the test rig for further experimental studies) is well below the smallest particle *** simulation of the dependence of the reconstruction accuracy on tracer particle location revealed a nearly constant efficiency within the entire detector system,which demonstrates that boundary effects can be neglected.

关键词： Positron emission particle tracking Monte Carlo method Time-of-flight Plastic scintillators Silicon photomultipliers(SiPMs)

A simulation study for a cost-effective PET-like detector system intended to track particles in granular assemblies

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Particuology 2024年第1期84卷 117-125页

作者： Josephine Oppotsch Antonios Athanassiadis Miriam Fritsch Fritz-herbert Heinsius Thomas Held Nikoline Hilse Viktor Scherer Matthias Steinke Ulrich Wiedner Ruhr-Universität Bochum Institut für Experimentalphysik I44801 BochumGermany Ruhr-Universität Bochum Lehrstuhl für Energieanlagen und Energieprozesstechnik44801 BochumGermany

Since many industrial applications rely on the processing of densely packed and moving granular ma-terial,obtaining bulk internal information on the particle movement inside the reactors is of great *** information can be delivered by Positron Emission Particle Tracking(PEPT).By marking pellets with a positron-emitting radioisotope,the position of these tracer particles can be determined via the time-of-flight differences of the emitted gamma-ray *** current paper proposes a PET-like detector system based on cost-effective organic plastic scintillators instead of the more common but expensive inorganic *** system is currently under construction and was tested for its resolution and efficiency in this simulation *** Monte Carlo simulations and the software toolkit Geant4,three different geometries(an empty glass box,a generic grate system,and a cubic box of 1 m3 completely filled with pellets)were investigated,leading to a spatial resolution in the millimeter range and an efficiency,defined as the ratio of reconstructed decay locations to simulated decays,of 2.7%,1.4%,and 0.3%.

关键词： Positron emission particle tracking Geant4 Monte Carlo method Time-of-flight Plastic scintillators Silicon photomultipliers(SiPMs)

Material-specific high-resolution table-top extreme ultraviolet microscopy

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Light(Science & Applications) 2022年第5期11卷 991-1000页

作者： Wilhelm Eschen Lars Loetgering Vittoria Schuster Robert Klas Alexander Kirsche lutz Berthold Michael Steinert Thomas Pertsch herbert Gross Michael Krause Jens Limpert Jan Rothhardt Institute of Applied Physics Abbe Center of PhotonicsFriedrich-SchillerUniversität JenaAlbert-Einstein-Str.1507745 JenaGermany HelmholtzInstitute Jena Fröbelstieg 307743 JenaGermany Leibniz Institute of Photonic Technology Albert-Einstein-Straße 907745 JenaGermany Fraunhofer Institute for Microstructure of Materials and Systems IMWS WalterHülse-Str.106120 HalleGermany Fraunhofer Institute for Applied Optics and Precision Engineering IOF Albert-Einstein-Str.707745 JenaGermany

Microscopy with extreme ultraviolet(EUV)radiation holds promise for high-resolution imaging with excellent material contrast,due to the short wavelength and numerous element-specific absorption edges available in this spectral *** the same time,EUV radiation has significantly larger penetration depths than *** thus enables a nano-scale view into complex three-dimensional structures that are important for material science,semiconductor metrology,and next-generation ***,we present high-resolution and material-specific microscopy at 13.5 nm *** combine a highly stable,high photon-flux,table-top EUV source with an interferometrically stabilized ptychography *** utilizing structured EUV illumination,we overcome the limitations of conventional EUV focusing optics and demonstrate high-resolution microscopy at a half-pitch lateral resolution of 16 ***,we propose mixed-state orthogonal probe relaxation ptychography,enabling robust phase-contrast imaging over wide fields of view and long acquisition *** this way,the complex transmission of an integrated circuit is precisely reconstructed,allowing for the classification of the material composition of mesoscopic semiconductor systems.

关键词： resolution ultraviolet extreme

Contribution of Bone Scintigraphy in the Metastatic Extension Assessment of Prostate Cancer: A Study of 288 Cases in the Nuclear Medicine Department of Idrissa Pouye General Hospital, Dakar

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Open Journal of Biophysics 2024年第2期14卷 79-98页

作者： El Hadji Amadou Lamine Bathily Ousseynou Diop Mamoudou Salif Djigo Gora Thiaw Kalidou Gueye Mohamed Chekhma Olatounde herbert Fachinan Boucar Ndong Omar Ndoye Mamadou Mbodj Department of Nuclear Medicine Idrissa Pouye General Hospital (HOGIP) Dakar Senegal Biophysical Laboratory FMPO Cheikh Anta Diop University (UCAD) Dakar Senegal Department of Nuclear Medicine Hospital Dalal Jamm Dakar Senegal

Introduction: Prostate cancer is the most frequently diagnosed male malignancy and the fifth leading cause of cancer death in men worldwide. Since the advent of screening methods such as Prostate Specific Antigen (PSA) assay, digital rectal examination (DRE) and prostate biopsy, its incidence has increased significantly. The aim of our study was to analyse aspects of bone scintigraphy (BS) as part of the metastatic extension assessment of prostate cancer in Senegal. Patients and Methods: This was a retrospective descriptive and analytical study, running from January 1er 2022 to August 31 2023. Patients with histologically confirmed prostate cancer were included. Whole-body scans (WBS) were performed using a dual-head SPECT gamma camera (Mediso Nucline TM Spirit DH-V type), 3 hours after intravenous injection of 8 MBq/kg (555 to 740 MBq) of 99mTc-HMDP. Results: A total of 288 patients with a mean age of 68.37 ± 7.79 years were included. The median total PSA level was 97.6 ng/ml, with 144 patients having a level greater than or equal to 20 ng/ml. All patients had adenocarcinoma, and the Gleason score was available in 202 (70.13%) patients, 75.75% of whom had a score greater than or equal to 7. BS was contributory in 70.48% of cases, with 30.90% positive and 39.58% negative. The result was inconclusive in 85 patients (29.51%). The mean PSA for patients with a positive scan was 190.2 ng/ml and 40.6 ng/ml for those with a negative scan. Multiple metastatic lesions predominated (87.35% of cases). Metastatic lesions occurred preferentially in the axial skeleton, with a proportion of 68% versus 32% in the appendicular skeleton. Classification of bone metastases according to the SOLOWAY score revealed grade I (62.07%), grade II (35.63%) and grade IV (2.30%). Conclusion: In Senegal, prostate cancer is generally diagnosed in men of advanced age. The presence of bone metastases is frequent in its evolution, transforming a curable localized disease into a g

关键词： Prostate Cancer Bone Metastasis Bone Scintigraphy Senegal

Place of Bone Scintigraphy in the Assessment of Extension and Follow-Up of Breast Cancer in Senegal: Study of 165 Cases in the Nuclear Medicine Department of Idrissa Pouye General Hospital (Dakar)

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Open Journal of Medical Imaging 2024年第1期14卷 10-30页

作者： El Hadji Amadou Lamine Bathily Mamoudou Salif Djigo Djimby Ba Gora Thiaw Ousseynou Diop Kalidou Gueye Olatounde herbert Fachinan Boucar Ndong Omar Ndoye Mamadou Mbodj Nuclear Medicine Department Idrissa Pouye General Hospital (HOGIP) Dakar Senegal Biophysics Laboratory FMPO UCAD Dakar Senegal Nuclear Medicine Department Hospital Dalal Jamm Dakar Senegal Nursing and Obstetrics Training Institute Parakou University Parakou Benin

Introduction: Breast cancer is the most common cancer in women worldwide, accounting for an estimated 22% of all female cancers. It is the leading cause of cancer mortality in women, almost all of which is due to metastases, with 73% of metastases occurring in the bone. In oncology, metastable technetium 99-labelled methylene bisphosphonate bone scintigraphy (BS) remains the standard examination for detecting and assessing the extent of bone metastases. The aim of this study was to assess the role of BS in the evaluation and follow-up of breast cancer in Senegal. Methodology: This was a retrospective study of breast cancer patients who underwent bone scintigraphy with 99mTc-HMDP in the nuclear medicine department of Idrissa Pouye General Hospital (IPGHO), from July 2009 to June 2022. Results: We enrolled 165 patients, mean age 46.79 years (27 - 87 years). BS was performed in 94.37% of cases for post-therapeutic monitoring and in 5.63% for pre-therapeutic assessment. Results were contributory in 131 patients (92.25%), of whom 72 cases (50.70%) were normal and 59 cases (41.55%) positive or presenting bone metastases;and non-contributory or doubtful in 11 cases (7.75%). Secondary bone locations were multiple in 57 cases (96.61%) and single or solitary in 2 cases (3.39%). The scintigraphic appearance of bone metastases was hyper-fixative in 58 cases (98.31%) and mixed in 1 case (1.69%). Bone lesions were quantified using the Soloway’s grading classification. Conclusion: BS with 99mTc-labelled bisphosphonates remains the examination of choice for skeletal exploration, in the detection and extension of bone metastases in breast cancer. Performance has been enhanced by the development of SPECT coupled with CT (SPECT-CT).

关键词： Breast Cancer Bone Scintigraphy 99mTc-HMDP Bone Metastases

Synthesis of Fréchet-type dendritic homotriptycenes

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Science China Chemistry 2009年第7期52卷 1051-1056页

作者： MEIER herbert School of Chemistry and Chemical Engineering South China University of Technology Institute of Organic Chemistry University of Mainz

A rapid and efficient synthesis of novel dendrimer homotriptycenes is presented. The dendronized 9,10-dihydroanthracen-9-ols 4, having high electron densities in the benzene rings of the Fréchet-type dendrons, exhibited in the presence of acid a quantitative transannular ring closure to the corresponding dendritic homotriptycenes. The electron-donating Fréchet-type dendrons enabled the intramolecular FC alkylation by a regioselective 1,7-elimination of H2O.

关键词： carbenium ions dendrimers ring closure reaction triptycene homotriptycene