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

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.

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Retrieval-and-alignment based large-scale indoor point cloud semantic segmentation

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Science China(Information Sciences) 2024年第4期67卷 164-180页

作者： Zongyi XU Xiaoshui HUANG bo yuan Yangfu WANG Qianni ZHANG Weisheng LI Xinbo GAO School of Computer Science and Technology Chongqing University of Posts and Telecommunications Chongqing Institute for Brain and Intelligence Guangyang Bay Laboratory 3. Shanghai Artificial Intelligence Laboratory School of Electronic Engineering and Computer Science Queen Mary University of London

Current methods for point cloud semantic segmentation depend on the extraction of descriptive features. However, unlike images, point clouds are irregular and often lack texture information, making it demanding to extract discriminative features. In addition, noise, outliers, and uneven point distribution are commonly present in point clouds, which further complicates the segmentation task. To address these problems, a novel architecture is proposed for direct and accurate large-scale point cloud segmentation based on point cloud retrieval and alignment. The proposed approach involves using a feature-based point cloud retrieval method for searching for reference point clouds with annotations from a dataset. In the following segmentation stage, an overlap-based point cloud registration method has been developed to align the target and reference point clouds. For accurate and robust alignment, an overlap region estimation module is trained to locate the optimal overlap region between two pieces of point clouds in a coarse-to-fine manner. In the detected overlap region, the global and local features of the points are extracted and combined for featuremetric registration to obtain accurate transformation parameters between the target and reference point clouds. After alignment, the annotated segmentation of the reference is transferred to the target point clouds to obtain accurate segmentation results. Extensive experiments are conducted to show that the developed method outperforms the state-of-the-art approaches in terms of both accuracy and robustness against noise and outliers.

关键词： point cloud semantic segmentation large-scale indoor point clouds point cloud alignment overlap estimation label transfer

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Laser powder bed fusion of NiTiFe shape memory alloy via premixed powder: microstructural evolution, mechanical and functional properties

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Rare Metals 2024年第5期43卷 2300-2316页

作者： bo yuan Jin-Guo Ge Liang Zhang Hong-Jun Chen Long-Sha Wei Yu-Duo Zhou Run-Hua Song Institute of Intelligent Manufacturing Technology Shenzhen Polytechnic School of Mechanical and Electrical Engineering Guilin University of Electronic Technology Guangdong Advanced Polymer Composite EngineeringTechnology Research Center Shenzhen Academy of Aerospace Technology Jihua Laboratory Testing Center Jihua Laboratory

High-cost pre-alloyed powder is the bottleneck problem that limits the widespread application of additivemanufactured shape memory alloys. In this work, the lowcost ternary NiTiFe shape memory alloy is fabricated by laser powder bed fusion (LPBF) technique via mechanically mixed pre-alloy NiTi powder and varying contents pure Fe powder (1, 2, 3 wt%). All NiTiFe alloys show a relative density of up to 99.8%by optimizing the LPBF processing parameters. Owing to the heterogeneous nucleation effect of micron-sized Fe particles, both grain refinement and texture weakening are generated in the NiTiFe alloys, accompanied by the reduction of dislocation density. For the room-temperature mechanical properties,the NiTi-3Fe alloy shows the highest microhardness of HV370, but the fracture strength and elongation reduce to1701 MPa and 23%simultaneously. The evolution of mechanical properties is attributed to the high internal defects, low dislocation density and the incoherent oxide.Moreover, the NiTi-3Fe alloy shows the quasi-linear superelasticity behavior; the superelastic recoverable strain of NiTi-1Fe and NiTi-2Fe decreased with the increase in Fe content. This study provided a new-fangled insight for the development of multi-component NiTi-based shape memory alloys by additive manufacturing.

关键词： Additive manufacturing Shape memory alloy Metal matrix composite Microstructure Mechanical properties

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Fractal Characteristics and Main Controlling Factors of High-Quality Tight Sandstone Reservoirs in the Southeastern Ordos Basin

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Journal of Earth Science 2024年第2期35卷 631-641页

作者： Ruilin Hao Wenhui Huang Jiu bo Li yuan Key Laboratory for Marine Reservoir Evolution and Hydrocarbon Abundance Mechanism School of Energy ResourcesChina University of GeosciencesMinistry of EducationBeijing100083China

Due to the complex conditions and strong heterogeneity of tight sandstone reservoirs,the reservoirs should be classified and the controlling factors of physical properties should be studied.Cast thin section observations,cathodoluminescence,scanning electron microscopy(SEM),X-ray diffraction(XRD),and high-pressure mercury injection(HPMI)were used to classify and optimize the reservoir.The Brooks-Corey model and stepwise regression were used to study the fractal dimension and main controlling factors of the physical properties of the high-quality reservoir.The results show that the reservoirs in the study area can be divided into four types,and the high-quality reservoir has the best physical properties and pore-throat characteristics.In the high-quality reservoir,the homogeneity of transitional pores was the best,followed by that of micropores,and the worst was mesopores.The porosity was controlled by depth and kaolinite.The model with standardized coefficients is y=12.454−0.778×(Depth)+0.395×(Kaolinite).The permeability was controlled by depth,illite/montmorillonite,and siliceous cement,and the model with standardized coefficients is y=1.689−0.683×(Depth)−0.395×(Illite/Montmorillonite)−0.337×(Siliceous Cement).The pore-throat evolutionary model shows that the early-middle diagenetic period was when the reservoir physical properties were at their best,and the kaolinite intercrystalline pores and residual intergranular pores were the most important.

关键词： fractal dimension main controlling factors stepwise regression high-quality tight sandstone reservoir Ordos Basin petroleum geolgoy

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On the Difference Between the Skew-rank of an Oriented Graph and the Rank of Its Underlying Graph

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Acta Mathematicae Applicatae Sinica 2024年第1期40卷 129-136页

作者： Jia-min Zhu bo-jun yuan Yi Wang School of Mathematical Sciences Anhui UniversityHefei230601China School of Science Zhejiang University of Science and TechnologyHangzhou310023China

Let G be a simple graph and G~σ be the oriented graph with G as its underlying graph and orientation σ.The rank of the adjacency matrix of G is called the rank of G and is denoted by r(G).The rank of the skew-adjacency matrix of G~σ is called the skew-rank of G~σ and is denoted by sr(G~σ).Let V(G)be the vertex set and E(G) be the edge set of G.The cyclomatic number of G,denoted by c(G),is equal to |E(G)|-|V(G)|+ω(G),where ω(G) is the number of the components of G.It is proved for any oriented graph G~σ that-2c(G)≤sr(G~σ)-r(G)≤2c(G).In this paper,we prove that there is no oriented graph G~σwith sr(G~σ)-r(G)=2c(G)-1,and in addition,there are infinitely many oriented graphs G~σ with connected underlying graphs such that c(G)=k and sr(G~σ)-r(G)=2c(G)-l for every integers k,l satisfying 0 ≤l≤4k and l≠1.

关键词： cyclomatic number rank skew-rank

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Dental-derived stem cells in tissue engineering:the role of biomaterials and host response

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Regenerative Biomaterials 2024年第1期3卷 17-26页

作者： Weihao yuan Luiza de Almeida Queiroz Ferreira bo Yu Sahar Ansari Alireza Moshaverinia Weintraub Center for Reconstructive Biotechnology Section of ProsthodonticsSchool of DentistryUniversity of CaliforniaLos AngelesLos AngelesCA 90095USA Department of Restorative Dentistry School of DentistryUniversidade Federal de Minas GeraisBelo HorizonteMinas GeraisBrazil Section of Restorative Dentistry School of DentistryUniversity of CaliforniaLos AngelesLos AngelesCA 90095USA Department of Bioengineering Henry Samueli School of Engineering and Applied SciencesUniversity of CaliforniaLos AngelesLos AngelesCA 90095USA

Dental-derived stem cells(DSCs)are attractive cell sources due to their easy access,superior growth capacity and low immunogenicity.They can respond to multiple extracellular matrix signals,which provide biophysical and biochemical cues to regulate the fate of residing cells.However,the direct transplantation of DSCs suffers from poor proliferation and differentiation toward functional cells and low survival rates due to local inflammation.Recently,elegant advances in the design of novel biomaterials have been made to give promise to the use of biomimetic biomaterials to regulate various cell behaviors,including proliferation,differentiation and migration.Biomaterials could be tailored with multiple functionalities,e.g.,stimuli-responsiveness.There is an emerging need to summarize recent advances in engineered biomaterials-mediated delivery and therapy of DSCs and their potential applications.Herein,we outlined the design of biomaterials for supporting DSCs and the host response to the transplantation.

关键词： dental-derived stem cells biomaterials host response tissue engineering

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Risk factors for recurrence of common bile duct stones after surgical treatment and effect of ursodeoxycholic acid intervention

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World Journal of Gastrointestinal Surgery 2024年第1期16卷 103-112页

作者： Wei-Hong yuan Zheng Zhang Qi Pan bo-Neng Mao Tao yuan Department of Gastroenterology Yixing People’s HospitalYixing 214200Jiangsu ProvinceChina

BACKGROUND Endoscopic retrograde cholangiopancreatography(ERCP)is an accurate diagnostic method for choledocholithiasis and treatment option for stone removal.Additionally,ursodeoxycholic acid(UDCA)can dissolve cholesterol stones and prevent their development and reappearance by lowering the cholesterol concen-tration in bile.Despite these treatment options,there are still patients who experience stone recurrence.The clinical data of 100 patients with choledochal stones who were hospitalized at the Yixing People’s Hospital and underwent ERCP for successful stone extraction between June 2020 and December 2022 were retrospectively collected.According to the post-ERCP treatment plan,100 patients were classified into UDCA(n=47)and control(n=53)groups.We aimed to assess the clinical efficacy and rate of relapse in the two patient populations.We then collected information(basic demographic data,clinical characteristics,and serum biochemical indicators)and determined the factors contributing to relapse using logistic regression analysis.Our secondary goal was to determine the effects of UDCA on liver function after ERCP.Compared to the control group,the UDCA group demonstrated a higher clinical effectiveness rate of 92.45%vs 78.72%(P<0.05).No significant differences were observed in liver function indices,including total bilirubin,direct bilirubin,gamma-glutamyl transpeptidase,alanine aminotransferase,alkaline phosphatase,and aspartate aminotransferase,between the two groups before treatment.After treatment,all liver function indices were significantly reduced.Comparing the control vs UDCA groups,the UDCA group exhibited significantly lower levels of all indices(55.39±6.53 vs 77.31±8.52,32.10±4.62 vs 45.39±5.69,142.32±14.21 vs 189.63±16.87,112.52±14.25 vs 149.36±15.36,122.61±16.00 vs 171.33±22.09,96.98±10.44 vs 121.35±11.57,respectively,all P<0.05).The stone recurrence rate was lower in the UDCA group(13.21%)in contrast with the control group(44.68%).Periampullary diverticula(OR:6.00,95%CI:1.69-21.30),maximum stone diam

关键词： Endoscopic retrograde cholangiopancreatography Recurrence Ursodeoxycholic acid Common bile duct stones Clinical effective rate Risk factors

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Rare esophageal carcinoma-primary adenoid cystic carcinoma of the esophagus: A case report

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World Journal of Clinical Cases 2024年第3期12卷 630-636页

作者： Li-Dan Geng Jie Li Li yuan Xiao-bo Du Department of Oncology Mianyang Central HospitalMianyang 621000Sichuan ProvinceChina

BACKGROUND Esophageal adenoid cystic carcinoma(EACC)is an exceedingly rare malignant tumor of the esophagus,posing significant challenges in the clinic.CASE SUMMARY This report detailed the case of a 72-year-old male whose diagnosis of EACC was confirmed through postoperative histopathological examination.The patient underwent thoracoscopy-assisted radical resection of the esophageal tumor,coupled with lymph node dissection.Pathological findings revealed an adenoid cystic carcinoma infiltrating the entire layer of the muscularis propria,locally extending into the outer membrane of the esophageal fiber,involving the cardia and exhibiting no lymph node metastasis.The patient’s condition was classified as primary EACC,T3N0M0,per the American Joint Committee on Cancer(2017;8th edition).One month after surgery,the patient received postoperative adjuvant radiation therapy.CONCLUSION In addressing the rarity and high potential for biopsy misdiagnosis of EACC,this study delved into its diagnostic methods and treatment.

关键词： Esophageal adenoid cystic carcinoma Malignant tumor Lymph node dissection Adjuvant radiation therapy Misdiagnosis Case report

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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 PD.Exploring the pathology at an early stage contributes to the development of the disease-modifying strategy.Although 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 understood.Here 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 months.Pathologicalα-synuclein propagation via CRN leads to neuron loss and disordered neuron activity,accompanied by abnormal motor and non-motor behavior.Potential neuron circuits are observed among CRN,LC,and SNpc,which contribute to the venerability of dopaminergic neurons in SNpc.These results show that CRN is the key region for the gastricα-synuclein spread to the midbrain.Our 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

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Vitamin A regulates mitochondrial biogenesis and function through p38 MAPK‑PGC‑1α signaling pathway and alters the muscle fiber composition of sheep

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Journal of Animal Science and Biotechnology 2024年第2期15卷 898-910页

作者： Pengkang Song Jiamin Zhao Fanqinyu Li Xiaoyi Zhao Jinxin Feng yuan Su bo Wang Junxing Zhao College of Animal Science Shanxi Agricultural UniversityTaiguShanxi 030801People’s Republic of China State Key Laboratory of Animal Nutrition and Feeding Department of Animal Nutrition and Feed ScienceCollege of Animal Science and TechnologyChina Agricultural UniversityBeijing 100193People’s Republic of China

Background Vitamin A(VA)and its metabolite,retinoic acid(RA),are of great interest for their wide range of physiological functions.However,the regulatory contribution of VA to mitochondrial and muscle fiber composition in sheep has not been reported.Method Lambs were injected with 0(control)or 7,500 IU VA palmitate into the biceps femoris muscle on d 2 after birth.At the age of 3 and 32 weeks,longissimus dorsi(LD)muscle samples were obtained to explore the effect of VA on myofiber type composition.In vitro,we investigated the effects of RA on myofiber type composition and intrinsic mechanisms.Results The proportion of type I myofiber was greatly increased in VA-treated sheep in LD muscle at harvest.VA greatly promoted mitochondrial biogenesis and function in LD muscle of sheep.Further exploration revealed that VA elevated PGC-1αmRNA and protein contents,and enhanced the level of p38 MAPK phosphorylation in LD muscle of sheep.In addition,the number of type I myofibers with RA treatment was significantly increased,and type IIx myofibers was significantly decreased in primary myoblasts.Consistent with in vivo experiment,RA significantly improved mitochondrial biogenesis and function in primary myoblasts of sheep.We then used si-PGC-1αto inhibit PGC-1αexpression and found that si-PGC-1αsignificantly abrogated RA-induced the formation of type I myofibers,mitochondrial biogenesis,MitoTracker staining intensity,UQCRC1 and ATP5A1 expression,SDH activity,and enhanced the level of type IIx muscle fibers.These data suggested that RA improved mitochondrial biogenesis and function by promoting PGC-1αexpression,and increased type I myofibers.In order to prove that the effect of RA on the level of PGC-1αis caused by p38 MAPK signaling,we inhibited the p38 MAPK signaling using a p38 MAPK inhibitor,which significantly reduced RA-induced PGC-1αand MyHC I levels.Conclusion VA promoted PGC-1αexpression through the p38 MAPK signaling pathway,improved mitochondrial biogenesis,and altered the composition of muscle fiber type.

关键词： Mitochondria Muscle fiber type PGC-1α p38 MAPK Retinoic acid Vitamin A

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