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On Robust Cross-view Consistency in Self-supervised Monocular Depth Estimation

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Machine Intelligence Research 2024年第3期21卷 495-513页

作者： Haimei Zhao Jing Zhang Zhuo chen bo yuan Dacheng Tao School of Computer Science University of SydneySydney2008Australia Shenzhen International Graduate School Tsinghua UniversityShenzhen518055China School of Information Technology&Electrical Engineering University of QueenslandBrisbane4072Australia

Remarkable progress has been made in self-supervised monocular depth estimation (SS-MDE) by exploring cross-view consistency, e.g., photometric consistency and 3D point cloud consistency. However, they are very vulnerable to illumination variance, occlusions, texture-less regions, as well as moving objects, making them not robust enough to deal with various scenes. To address this challenge, we study two kinds of robust cross-view consistency in this paper. Firstly, the spatial offset field between adjacent frames is obtained by reconstructing the reference frame from its neighbors via deformable alignment, which is used to align the temporal depth features via a depth feature alignment (DFA) loss. Secondly, the 3D point clouds of each reference frame and its nearby frames are calculated and transformed into voxel space, where the point density in each voxel is calculated and aligned via a voxel density alignment (VDA) loss. In this way, we exploit the temporal coherence in both depth feature space and 3D voxel space for SS-MDE, shifting the “point-to-point” alignment paradigm to the “region-to-region” one. Compared with the photometric consistency loss as well as the rigid point cloud alignment loss, the proposed DFA and VDA losses are more robust owing to the strong representation power of deep features as well as the high tolerance of voxel density to the aforementioned challenges. Experimental results on several outdoor benchmarks show that our method outperforms current state-of-the-art techniques. Extensive ablation study and analysis validate the effectiveness of the proposed losses, especially in challenging scenes. The code and models are available at https://***/sunnyHelen/RCVC-depth.

关键词： 3D vision depth estimation cross-view consistency self-supervised learning monocular perception

The raphe nuclei are the early lesion site of gastric α-synuclein propagation to the substantia nigra

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Acta Pharmaceutica Sinica B 2024年第5期14卷 2057-2076页

作者： chenglu Zhang Ruxue bo Tiantian Zhou Naihong chen Yuhe yuan State Key Laboratory of Bioactive Substances and Functions of Natural Medicines Chinese Academy of Medical Sciences&Peking Union Medical College Institute of Materia MedicaBeijing 100050China

Parkinson's disease(PD)is a neurodegeneration disease withα-synuclein accumulated in the substantia nigra pars compacta(SNpc)and most of the dopaminergic neurons are lost in SNpc while patients are diagnosed with *** the pathology at an early stage contributes to the development of the disease-modifying *** the“gut–brain”hypothesis is proposed to explain the underlying mechanism,where the earlier lesioned site in the brain of gastricα-synuclein and howα-synuclein further spreads are not fully *** we report that caudal raphe nuclei(CRN)are the early lesion site of gastricα-synuclein propagating through the spinal cord,while locus coeruleus(LC)and substantia nigra pars compacta(SNpc)were further affected over a time frame of 7 ***α-synuclein propagation via CRN leads to neuron loss and disordered neuron activity,accompanied by abnormal motor and non-motor *** neuron circuits are observed among CRN,LC,and SNpc,which contribute to the venerability of dopaminergic neurons in *** results show that CRN is the key region for the gastricα-synuclein spread to the *** study provides valuable details for the“gut–brain”hypothesis and proposes a valuable PD model for future research on early PD intervention.

关键词： Raphe nuclei α-Synuclein Gastrointestinal tract Electrophysiology Locus coeruleus Substantia nigra pars compacta Parkinson's disease Spinal cord

Multi-stimuli-responsive aggregation-induced emission copper iodide cluster

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Science China Chemistry 2024年第4期67卷 1193-1197页

作者： bo Li yuan-yuan Liu Peng Luo Ye-Ru Liu Ying-Jun chen Kai Li Shuang-Quan Zang College of Chemistry and Pharmacy Engineering Nanyang Normal UniversityNanyang 473061China Green Catalysis Center and College of Chemistry Zhengzhou UniversityZhengzhou 450001China

Stimuli-responsive luminescent materials have attracted significant attention in the development of smart photoactive materials for both fundamental research and technological *** this work,a new copper iodide cluster(1)with aggregationinduced emission(AIE)characteristic,was obtained combining Cu_(4)I_(4) core with rhodamine B derivative ligand.1 has reversible and distinct multi-stimuli-responsive luminescence for external temperature,volatile organic compound,and mechanical ***,1 exhibited unusual large blue shift(84 nm)after being ground,which originated from the change of intermolecular ***,1 exhibits high oxygen quenching efficiency for 82.2% at 1 *** studies showed that the multi-stimuli-responsive luminescence properties of 1 can be attributed to the regulation of cluster-centered luminescence process,metal-to-ligand charge transfer process,halide-to-metal charge transfer luminescence process and aggregationinduced barrier to oxygen *** work not only reports an AIE copper iodide cluster,but also provides a new strategy to develop multi-stimuli-responsive luminescence materials.

关键词： copper iodide cluster aggregation-induced emission multi-stimuli-response

Human umbilical cord mesenchymal stem cells derivedexosomes on VEGF-A in hypoxic-induced mice retinal astrocytes and mice model of retinopathy of prematurity

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International Journal of Ophthalmology(English edition) 2024年第7期17卷 1238-1247页

作者： Xiao-Tian Zhang bo-Wen Zhao yuan-Long Zhang Song chen Tianjin Eye Hospital Tianjin 300020China Tianjin Key Lab of Ophthalmology and Visual Science Tianjin 300020China

AIM:To observe the effect of human umbilical cord mesenchymal stem cells(hUCMSCs)secretions on the relevant factors in mouse retinal astrocytes,and to investigate the effect of hUCMSCs on the expression of vascular endothelial growth factor-A(VEGF-A)and to observe the therapeutic effect on the mouse model of retinopathy of prematurity(ROP).METHODS:Cultured hUCMSCs and extracted exosomes from them and then retinal astrocytes were divided into control group and hypoxia *** assay,flow cytometry,reverse transcription-polymerase chain reaction(RT-PCR)and Western blot were used to detect related *** mechanisms by which hUCMSCs exosomes affect VEGF-A expression in hypoxia-induced mouse retinal astrocytes were *** last,the efficacy of exosomes of UCMSCs in a mouse ROP model was ***6 was used to comprehensively process data ***:The secretion was successfully extracted from the culture supernatant of hUCMSCs by gradient *** oxygen species(ROS)and hypoxia inducible factor-1α(HIF-1α)of mice retinal astrocytes under different hypoxia time and the expression level of VEGF-A protein and VEGF-A mRNA increased,and the ROP cell model was established after 6h of *** secretions of medium and high concentrations of hUCMSCs can reduce ROS and HIF-1α,the expression levels of VEGF-A protein and VEGF-A mRNA are statistically significant and concentration *** with the ROP cell model group,the expression of phosphatidylinositol 3-kinase(PI3K)/protein kinase B(AKT)/mammalian target of rapamycin(mTOR)signal pathway related factors in the hUCMSCs exocrine group is significantly *** intravitreal injection of the secretions of medium and high concentrations of hUCMSCs can reduce VEGF-A and HIF-1αin ROP model *** staining shows that the number of retinal neovascularization in ROP mice decreases with the increase of the dose of hUCMSCs ***:In a hypoxia induced

关键词： human umbilical cord mesenchymal stem cells retinal astrocytes retinopathy of prematurity vascular endothelial growth factor hypoxia inducible factor

Development of a high-repetition-rate lumped-inductance kicker magnet prototype for the beam switchyard of SHINE

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Nuclear Science and Techniques 2024年第2期35卷 20-31页

作者： Yong-Fang Liu Rui-Ping Wang Jin Tong bo Zhang Si chen Qi-Bing yuan Hai-Xiao Deng Ming Gu bo Liu Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201412People’s Republic of China

The Shanghai high-repetition-rate X-ray free-electron laser and extreme light facility(SHINE)operates at a maximum repetition rate of 1 *** magnets are key components that distribute electron bunches into three different undulator lines in a bunch-by-bunch *** kicker field width must be less than the time interval between bunches.A lumpedinductance kicker prototype was developed using a vacuum chamber with a single-turn *** full magnetic field strength was 0.005 *** paper presents the requirements,design considerations,design parameters,magnetic field calculations,and measurements of the kicker *** relevant experimental results are also *** pulse width of the magnetic field was approximately 600 ns,and the maximum operation repetition rate was 1 *** developed kicker satisfies the requirements for the SHINE ***,numerous recommendations for the future optimization of kicker magnets are provided.

关键词： X-ray free-electron laser Kicker magnet Beam switchyard High repetition rate Ni-Zn ferrites

p38 Signaling Mediates Naringin-Induced Osteogenic Differentiation of Porcine Metanephric Mesenchymal Cells

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Chinese Journal of Integrative Medicine 2024年第9期30卷 818-825页

作者： JI Peng-cheng XIE yuan-sheng GUO Wen-kai FU bo chen Xiang-mei Chinese PLA Medical School Beijing100853China Department of Nephrology First Medical Center of Chinese PLA General HospitalChinese PLA Institute of NephrologyState Key Laboratory of Kidney DiseasesNational Clinical Research Center for Kidney DiseasesBeijing Key Laboratory of Kidney DiseasesBeijing100853China School of Medicine Nankai UniversityTianjin300071China

Objective:To explore the potential of metanephric mesenchymal cells(MMCs)for osteogenesis and naringin’s ability to enhance this process and its molecular ***:Porcine MMCs at 70 days of gestation were used as tool cells,cultured in osteogenic induction medium,identified by immunocytochemistry *** potential of porcine MMCs and naringin’s ability to enhance this process was tested by detecting changes in cell viability,alkaline phosphatase(ALP)activity,the expression of runt-related transcription factor 2(Runx2),osteopontin(OPN)and osteocalcin(OCN),and the formation of mineralized nodules,and the application of the p38 signaling pathway inhibitor SB203580 vitiated the osteogenesis-promoting effect of ***:Immunocytochemical staining showed that the cells were Vimentin and Six2(+),E-cadherin and CK-18(−).Naringin can activate the p38 signaling pathway to enhance the osteogenesis of porcine MMCs by increasing cell viability,ALP activity,the expressions of Runx2,OPN and OCN,and the formation of mineralized nodules(Pbone,enhances the osteogenic differentiation of renal MMCs through the p38 signaling pathway.

关键词： metanephric mesenchymal cells naringin osteogenesis differentiation

An Accelerated Stochastic Mirror Descent Method

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Journal of the Operations Research Society of China 2024年第3期12卷 549-571页

作者： bo-Ou Jiang Ya-Xiang yuan LSEC ICMSECAMSSChinese Academy of SciencesBeijing100190China Department of Mathematics University of Chinese Academy of SciencesBeijing100049China

Driven by large-scale optimization problems arising from machine learning,the development of stochastic optimization methods has witnessed a huge *** types of methods have been developed based on vanilla stochastic gradient descent ***,for most algorithms,convergence rate in stochastic setting cannot simply match that in deterministic *** understanding the gap between deterministic and stochastic optimization is the main goal of this ***,we are interested in Nesterov acceleration of gradient-based *** our study,we focus on acceleration of stochastic mirror descent method with implicit regularization *** that the problem objective is smooth and convex or strongly convex,our analysis prescribes the method parameters which ensure fast convergence of the estimation error and satisfied numerical performance.

关键词： Large-scale optimization Variance reduction Mirror descent Acceleration Independent sampling Importance sampling

Creep property and microstructural evolution of DD11 alloy under high temperature and low stress

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Rare Metals 2024年第2期43卷 810-816页

作者： Yan-Fei Liu Jiang-bo Sha Yun-Song Zhao chen-Guang Liu yuan-yuan Guo Jian Zhang Yu-Shi Luo School of Materials Science and Engineering Beihang UniversityBeijing100191China Science and Technology on Advanced High Temperature Structural Materials Laboratory Beijing Institute of Aeronautical MaterialsBeijing100095China

In this paper,the interrupted and ruptured creep tests were carried out in a novel second generation single crystal superalloy named DD11 at 1100℃/130 *** alloy exhibited typical creep curve including primary,steady,and tertiary three creep *** microstructural evolution at different stages of the creep were analyzed by scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The results show that theγ′phases transform into rafted structure at the early stage of the steady creep and keep stable during the steady creep *** the creep goes on,the rafted structure further coarsens and the topological inversion *** addition,at the primary creep,the dislocations mainly move in theγmatrix and pile up in theγ/γ′interface since the matrix channels widen *** formation of the regular interfacial dislocation networks occurs at the early stage of the steady *** the low stress,the dominated deformation mechanism during steady creep stage is the climbing of the〈010〉type edge ***,the effect of the deformation mechanism on creep property was discussed in detail.

关键词： DD11 alloy Creep property Interrupted creep test Rafted structure Deformation mechanism

Path-Dependent Progressive Failure Analysis for 3D-Printed Continuous Carbon Fibre Reinforced Composites

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Chinese Journal of Mechanical Engineering 2024年第4期37卷 84-93页

作者： yuan chen Lin Ye School of System Design and Intelligent Manufacturing(SDIM) Southern University of Science and TechnologyShenzhen 518055China Shenzhen Key Laboratory of Intelligent Manufacturing for Continuous Carbon Fibre Reinforced Composites Southern University of Science and TechnologyShenzhen 518055China

In order to predict the damage behaviours of 3D-printed continuous carbon fibre(CCF)reinforced composites,when additional short carbon fibre(SCF)composite components are employed for continuous printing or special functionality,a novel path-dependent progressive failure(PDPF)numerical approach is ***,a progressive failure model using Hashin failure criteria with continuum damage mechanics to account for the damage initiation and evaluation of 3D-printed CCF reinforced polyamide(PA)composites is developed,based on actual fibre placement trajectories with physical measurements of 3D-printed CCF/PA ***,an elastic-plastic model is employed to predict the plastic damage behaviours of SCF/PA ***,the accuracy of the PDPF model was validated so as to study 3D-printed CCF/PA composites with either negative Poisson's ratio or high *** results demonstrate that the proposed PDPF model can achieve higher prediction accuracies in mechanical properties of these 3D-printed CCF/PA *** analyses show that the stress distribution is generally aggregated in the CCF areas along the fibre placement paths,and the shear damage and matrix tensile/compressive damage are the key damage *** study provides a new approach with valuable information for characterising complex 3D-printed continuous fibre-matrix composites with variable mechanical properties and multiple constituents.

关键词： 3D printing Continuous carbon fibre Modelling Energy absorption Negative Poisson's ratio