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Strong invariance principle for a counterbalanced random walk

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Applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 370-380页

作者： TAN Hui-qun HU Zhi-shui DONG Liang International Institute of Finance School of ManagementUniversity of Science and Technology of ChinaHefei 230026China center for Basic Teaching and experiment Nanjing University of Science and TechnologyJiangyin 214443China

We study a counterbalanced random walkS_(n)=X_(1)+…+X_(n),which is a discrete time non-Markovian process andX_(n) are given recursively as follows.For n≥2,X_(n) is a new independent sample from some fixed law̸=0 with a fixed probability p,andX_(n)=−X_(v(n))with probability 1−p,where v(n)is a uniform random variable on{1;…;n−1}.We apply martingale method to obtain a strong invariance principle forS_(n).

关键词： random walk martingale invariance principle

Soil disturbance evaluation of soft clay based on stress-normalized smallstrain stiffness

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 990-999页

作者： Yanguo Zhou Yu Tian Junneng Ye Xuecheng Bian Yunmin Chen MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering Institute of Geotechnical EngineeringCenter for Hypergravity Experiment and Interdisciplinary ResearchZhejiang UniversityHangzhou310058China Ningbo Rail Transit Group Co. Ltd.Ningbo315010China

Soil disturbance includes the change of stress state and the damage of soil structure.The field testing indices reflect the combined effect of both changes and it is difficult to identify the soil structure disturbance directly from these indices.In the present study,the small-strain shear modulus is used to characterize soil structure disturbance by normalizing the effective stress and void ratio based on Hardin equation.The procedure for evaluating soil sampling disturbance in the field and the further disturbance during the subsequent consolidation process in laboratory test is proposed,and then validated by a case study of soft clay ground.Downhole seismic testing in the field,portable piezoelectric bender elements for the drilled sample and bender elements in triaxial apparatus for the consolidated sample were used to monitor the shear wave velocity of the soil from intact to disturbed and even remolded states.It is found that soil sampling disturbance degree by conventional thin-wall sampler is about 30%according to the proposed procedure,which is slightly higher than that from the modified volume compression method proposed by Hong and Onitsuka(1998).And the additional soil disturbance induced by consolidation in laboratory could reach about 50%when the consolidation pressure is far beyond the structural yield stress,and it follows the plastic volumetric strain quite well.

关键词： Natural clay Soil sample disturbance Shear wave velocity Small-strain shear modulus Hardin equation

Constitutive modelling of concrete material subjected to low-velocity projectile impact:insights into damage mechanism and target resistance

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第2期25卷 161-182页

作者： Shen LIU Xieping HUANG Xiangzhen KONG Qin FANG center for Hypergravity experiment and Interdisciplinary Research Zhejiang UniversityHangzhou310058China Institute of Geotechnical Engineering Zhejiang UniversityHangzhou310058China State Key Laboratory of Disaster Prevention&Mitigation of Explosion&Impact Army Engineering University of PLANanjing210007China

This paper presents a numerical study to improve the understanding of the complex subject of penetration and perforation of concrete targets impacted by low-velocity projectiles.The main focus is on the damage mechanisms and the major factors that account for the target resistance of the concrete.An improved continuous surface cap model recently proposed was employed.The model was first equipped with element erosion criteria and was adequately validated by comparisons with ballistic experiments.Comprehensive numerical simulations were carried out where the individual influence of tensile,shear,and volumetric behaviors(pore collapse)of a concrete target on its ballistic performance was investigated.Results demonstrated that cratering on the front face and scabbing on the rear face of the concrete target were mainly dominated by its tensile behavior.The major target resistance came from the second tunneling stage which was primarily governed by the shear and volumetric behaviors of the concrete.Particularly,this study captured the pore collapse-induced damage phenomenon during the high-pressure tunneling stage,which has been extensively reported in experiments but has usually been neglected in previous numerical investigations.

关键词： Penetration Perforation Damage mechanism Target resistance Projectile impact Pore collapse

PHLDA2 reshapes the immune microenvironment and induces drug resistance in hepatocellular carcinoma

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Oncology Research 2024年第6期32卷 1063-1078页

作者： KUN FENG HAO PENG QINGPENG LV YEWEI ZHANG Hepatopancreatobiliary center The Second Affiliated Hospital of Nanjing Medical UniversityNanjing210000China medical School Southeast UniversityNanjing210000China

Hepatocellular carcinoma(HCC)is a malignancy known for its unfavorable prognosis.The dysregulation of the tumor microenvironment(TME)can affect the sensitivity to immunotherapy or chemotherapy,leading to treatment failure.The elucidation of PHLDA2’s involvement in HCC is imperative,and the clinical value of PHLDA2 is also underestimated.Here,bioinformatics analysis was performed in multiple cohorts to explore the phenotype and mechanism through which PHLDA2 may affect the progression of HCC.Then,the expression and function of PHLDA2 were examined via the qRT-PCR,Western Blot,and MTT assays.Our findings indicate a substantial upregulation of PHLDA2 in HCC,correlated with a poorer prognosis.The methylation levels of PHLDA2 were found to be lower in HCC tissues compared to normal liver tissues.Besides,noteworthy associations were observed between PHLDA2 expression and immune infiltration in HCC.In addition,PHLDA2 upregulation is closely associated with stemness features and immunotherapy or chemotherapy resistance in HCC.In vitro experiments showed that sorafenib or cisplatin significantly up-regulated PHLDA2 mRNA levels,and PHLDA2 knockdown markedly decreased the sensitivity of HCC cells to chemotherapy drugs.Meanwhile,we found that TGF-βinduced the expression of PHLDA2 in vitro.The GSEA and in vitro experiment indicated that PHLDA2 may promote the HCC progression via activating the AKT signaling pathway.Our study revealed the novel role of PHLDA2 as an independent prognostic factor,which plays an essential role in TME remodeling and treatment resistance in HCC.

关键词： HCC Immune infiltration Drug resistance TME PHLDA2

circPVT1 promotes silica-induced epithelial-mesenchymal transition by modulating the miR-497-5p/TCF3 axis

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Journal of Biomedical Research 2024年第2期38卷 163-174,I0011-I0015页

作者： Siyun Zhou Yan Li Wenqing Sun Dongyu Ma Yi Liu Demin Cheng Guanru Li Chunhui Ni Department of Occupational medical and Environmental Health Key Laboratory of Modern Toxicology of Ministry of EducationCenter for Global HealthSchool of Public HealthNanjing Medical UniversityNanjingJiangsu 211166China Biomedical Publications center Nanjing Medical UniversityNanjingJiangsu 211166China Gusu School Nanjing Medical UniversityNanjingJiangsu 211166China

Epithelial-mesenchymal transition(EMT)is a vital pathological feature of silica-induced pulmonary fibrosis.However,whether circRNA is involved in the process remains unclear.The present study aimed to investigate the role of circPVT1 in the silica-induced EMT and the underlying mechanisms.We found that an elevated expression of circPVT1 promoted EMT and enhanced the migratory capacity of silica-treated epithelial cells.The isolation of cytoplasmic and nuclear separation assay showed that circPVT1 was predominantly expressed in the cytoplasm.RNA immunoprecipitation assay and RNA pull-down experiment indicated that cytoplasmic-localized circPVT1 was capable of binding to miR-497-5p.Furthermore,we found that miR-497-5p attenuated the silica-induced EMT process by targeting transcription factor 3(TCF3),an E-cadherin transcriptional repressor,in the silica-treated epithelial cells.Collectively,these results reveal a novel role of the circPVT1/miR-497-5p/TCF3 axis in the silica-induced EMT process in lung epithelial cells.Once validated,this finding may provide a potential theoretical basis for the development of interventions and treatments for pulmonary fibrosis.

关键词： silicosis epithelial-mesenchymal transition circPVT1 miR-497-5p TCF3

High-throughput screening of novel TFEB agonists in protecting against acetaminopheninduced liver injury in mice

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Acta Pharmaceutica Sinica B 2024年第1期14卷 190-206页

作者： Xiaojuan Chao Mengwei Niu Shaogui Wang Xiaowen Ma Xiao Yang Hua Sun Xujia Hu Hua Wang Li Zhang Ruili Huang Menghang Xia Andrea Ballabio Hartmut Jaeschke Hong-Min Ni Wen-Xing Ding Department of Pharmacology Toxicology and TherapeuticsUniversity of Kansas Medical CenterKansas CityKS 66160USA NMPA Key Laboratory for Research and Evaluation of Drug Metabolism&Guangdong Provincial Key Laboratory of New Drug Screening School of Pharmaceutical SciencesSouthern Medical UniversityGuangzhou 510515China Department of Oncology the First Affiliated Hospital of Anhui Medical UniversityAnhui Medical UniversityHefei 230032China National center for Advancing Translational Sciences National Institutes of HealthBethesdaMD 20892USA Telethon Institute of Genetics and Medicine TIGEMPozzuoliNaples 80131Italy medical Genetics Department of Translational MedicineFederico II UniversityNaples 80131Italy Department of Molecular and Human Genetics Baylor College of MedicineHoustonTX 77030USA Department of Internal Medicine Division of GastroenterologyHepatology&MotilityUniversity of Kansas Medical CenterKansas CityKS 66160USA

Macroautophagy(referred to as autophagy hereafter)is a major intracellular lysosomal degradation pathway that is responsible for the degradation of misfolded/damaged proteins and organelles.Previous studies showed that autophagy protects against acetaminophen(APAP)-induced injury(AILI)via selective removal of damaged mitochondria and APAP protein adducts.The lysosome is a critical organelle sitting at the end stage of autophagy for autophagic degradation via fusion with autophagosomes.In the present study,we showed that transcription factor EB(TFEB),a master transcription factor for lysosomal biogenesis,was impaired by APAP resulting in decreased lysosomal biogenesis in mouse livers.Genetic loss-of and gain-of function of hepatic TFEB exacerbated or protected against AILI,respectively.Mechanistically,overexpression of TFEB increased clearance of APAP protein adducts and mitochondria biogenesis as well as SQSTM1/p62-dependent non-canonical nuclear factor erythroid 2-related factor 2(NRF2)activation to protect against AILI.We also performed an unbiased cell-based imaging high-throughput chemical screening on TFEB and identified a group of TFEB agonists.Among these agonists,salinomycin,an anticoccidial and antibacterial agent,activated TFEB and protected against AILI in mice.In conclusion,genetic and pharmacological activating TFEB may be a promising approach for protecting against AILI.

关键词： Autophagy DILI Drug screening Hepatotoxicity Lysosome Mitochondria Mitophagy NRF2

Towards accurate mapping of loess waterworn gully by integrating google earth imagery and DEM using deep learning

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International Soil and Water Conservation Research 2024年第1期12卷 13-28页

作者： Rong Chen Yi Zhou Zetao Wang Ying Li Fan Li Feng Yang School of Geography and Tourism Shaanxi Normal UniversityXi'an710119China National experiment and Teaching Demonstration center for Geography Xi'an710119China SuperMap Software Co. Ltd.Beijing100015China School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhen518055China

Accurate mapping of loess waterworn gully(LWG)is essential to further study gully erosion and geomorphological evolution for the Chinese Loess Plateau(CLP).Due to the vertical joint and collapsibility of loess,LWGs have the characteristics of zigzag and unique slope abruptness under synthetic action of hydraulic force and gravity.This forces existing LWG mapping methods to either focus on the improvement of mapping accuracy or center on the increase of mapping efficiency.However,simultaneously achieving accurate and efficient mapping of LWG is still in its infancy under complex topographic conditions.Here,we proposed a method that innovatively integrates the loess slope abruptness feature into an improved deep learning semantic segmentation framework for LWG mapping using 0.6 m Google imagery and 5 m DEM data.We selected four study areas representing typical loess landforms to test the performance of our method.The proposed method can achieve satisfactory mapping results,with the F1 score,mean Intersection-over-Union(mIoU),and overall accuracy of 90.5%,85.3%,and 92.3%,respectively.In addition,the proposed model also showed significant accuracy improvement by inputting additional topographic information(especially the slope of slope).Compared with existing algorithms(Random forests,original DeepLabV3+,and Unet),the proposed approach in this study achieved a better accuracy-efficiency trade-off.Overall,the method can ensure high accuracy and efficiency of the LWG mapping for different loess landform types and can be extended to study various loess gully mapping and water and soil conservation.

关键词： Loess waterworn gully Topographic information Mapping Deep learning Soil erosion Loess plateau

The Application of Permanent Magnet Synchronous Motor with Small Electrical Time Constant in Fiber Positioner

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Research in Astronomy and Astrophysics 2024年第1期24卷 212-222页

作者： Shaoxiong Guo Yan Yang Yanbin Yin Yihu Tang Yang Tian Chao Zhai Department of Precision Machinery and Precision Instrumentation University of Science and Technology of ChinaHefei 230026China School of Biomedical Engineering Division of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefei 230026China experiment center of Engineering and Material Science University of Science and Technology of ChinaHefei 230026China

With the development of cutting-edge multi-object spectrographs,fiber positioners located in the focal plane are being scaled down in size,and miniature hollow-cup Permanent Magnet motors are now being considered as a suitable replacement for Faulhaber Precistep stepper motors.However,the small electrical time constant of such coreless motors poses a challenge,as the problem of severe commutation torque ripple in a fiber positioner running a position loop has been tricky.To overcome this challenge,it is advised to increase the Pulse Width Modulation(PWM)frequency as much as possible to mitigate the effects of the current fluctuation.This must be done while ensuring adequate resolution of the PWM generator.By employing a voltage open-loop field-oriented control based on a modulation frequency of 1 MHz,the drive current only costs 25 m A under a 3.3 V power supply.The sine degree of phase current is immaculate,and the repeat positioning accuracy can reach 2μm.Moreover,it is possible to further shrink the bill of devices and the layout area of the Printed Circuit Board,especially in sizesensitive applications.This device has been developed under the new generation of The Large Sky Area MultiObject Fiber Spectroscopic Telescope.

关键词： instrumentation:adaptive optics instrumentation:spectrographs proper motions reference systems

experimental and numerical investigation of the impacts of rotor tip-rake on excitation forces of pump-jet propulsors

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Journal of Hydrodynamics 2024年第1期36卷 142-157页

作者： Xue-qin Ji Xiao-song Zhang Chen-jun Yang Xiao-qian Dong State Key Laboratory of Ocean Engineering Marine Numerical Experiment CentreSchool of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China CSSC Shanghai Marine Energy Saving Technology Co. Ltd.Shanghai200011China China Ship Scientific Research center Shanghai Branch Shanghai200011China

The tip-clearance flow in a pump-jet propulsor exerts great impacts on the fluctuating pressures and resultant unsteady forces,which are important sources of structural vibrations and radiated noise underwater.The blade geometry close to the tip is an important factor determining the vortex strength in the tip-clearance flow.In the open-water condition,the effects of raking the rotor tips on the duct-surface fluctuating pressures and the resultant unsteady forces acting on different components of the propulsor are investigated via physical model experiments and the numerical solution of Reynolds-averaged Navier-Stokes(RANS)equations coupled with the SST k-ωturbulence model.The measured and simulated results of hydrodynamic pressures are consistent to each other,and the simulated flows help better understand why the fluctuating pressures change with the tip geometry.The strong fluctuations of duct-surface pressures are caused by intensive tip separation vortices.The duct-surface pressure fluctuations are effectively reduced by using the rake distribution near the tip towards blade back side and,for the combination of the five-bladed rotor and the seven-bladed stator,the resultant unsteady horizontal(and vertical)forces acting on the duct and stator are also reduced;while increasing rake leads to negative effect on pressure fluctuations and unsteady horizontal(and vertical)forces acting on all the components of the propulsor.

关键词： Pump-jet tip-clearance tip-rake fluctuating pressures excitation forces