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Improving corrosion resistance of additively manufactured WE43 magnesium alloy by high temperature oxidation for biodegradable applications

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Journal of Magnesium and Alloys 2024年第3期12卷 940-953页

作者： Jinge Liu Bangzhao Yin Fei Song Bingchuan Liu Bo Peng Peng Wen yun tian Yufeng Zheng Xiaolin Ma Caimei Wang State Key Laboratory of Tribology in Advanced Equipment Beijing100084China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Department of Orthopaedics Beijing Tsinghua Changgung HospitalInstitute for Precision MedicineTsinghua UniversityBeijing102218China Department of Orthopaedics Peking University Third HospitalBeijing 100191China Engineering Research Center of Bone and Joint Precision Medicine Ministry of EducationBeijing 100191China School of Materials Science and Engineering Peking UniversityBeijing 100871China Beijing AKEC Medical Co. Ltd.Beijing 102200China

Laser powder bed fusion(L-PBF)has been employed to additively manufacture WE43 magnesium(Mg)alloy biodegradable implants,but WE43 L-PBF samples exhibit excessively rapid corrosion.In this work,dense WE43 L-PBF samples were built with the relativity density reaching 99.9%.High temperature oxidation was performed on the L-PBF samples in circulating air via various heating temperatures and holding durations.The oxidation and diffusion at the elevated temperature generated a gradient structure composed of an oxide layer at the surface,a transition layer in the middle and the matrix.The oxide layer consisted of rare earth(RE)oxides,and became dense and thick with increasing the holding duration.The matrix was composed ofα-Mg,RE oxides and Mg_(24)RE_(5) precipitates.The precipitates almost disappeared in the transition layer.Enhanced passivation effect was observed in the samples treated by a suitable high temperature oxidation.The original L-PBF samples lost 40%weight after 3-day immersion in Hank’s solution,and broke into fragments after 7-day immersion.The casted and solution treated samples lost roughly half of the weight after 28-day immersion.The high temperature oxidation samples,which were heated at 525℃ for 8 h,kept the structural integrity,and lost only 6.88%weight after 28-day immersion.The substantially improved corrosion resistance was contributed to the gradient structure at the surface.On one hand,the outmost dense layer of RE oxides isolated the corrosive medium;on the other hand,the transition layer considerably inhibited the corrosion owing to the lack of precipitates.Overall,high temperature oxidation provides an efficient,economic and safe approach to inhibit the corrosion of WE43 L-PBF samples,and has promising prospects for future clinical applications.

关键词： Laser powder bed fusion Biodegradable magnesium alloy High temperature oxidation Corrosion resistance WE43.

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Influence of layer thickness on formation quality,microstructure,mechanical properties,and corrosion resistance of WE43 magnesium alloy fabricated by laser powder bed fusion

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Journal of Magnesium and Alloys 2024年第4期12卷 1367-1385页

作者： Bangzhao Yin Jinge Liu Bo Peng Mengran Zhou Bingchuan Liu Xiaolin Ma Caimei Wang Peng Wen yun tian Yufeng Zheng State Key Laboratory of Tribology in Advanced Equipment Beijing100084China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Institute for Precision Medicine Tsinghua UniversityBeijing102218China Department of Orthopaedics Peking University Third HospitalBeijing 100191China Beijing AKEC Medical Co. Ltd.Beijing 102200China School of Materials Science and Engineering Peking UniversityBeijing 100871China Engineering Research Center of Bone and Joint Precision Medicine Ministry of EducationBeijing 100191China

Laser powder bed fusion(L-PBF)of Mg alloys has provided tremendous opportunities for customized production of aeronautical and medical parts.Layer thickness(LT)is of great significance to the L-PBF process but has not been studied for Mg alloys.In this study,WE43 Mg alloy bulk cubes,porous scaffolds,and thin walls with layer thicknesses of 10,20,30,and 40μm were fabricated.The required laser energy input increased with increasing layer thickness and was different for the bulk cubes and porous scaffolds.Porosity tended to occur at the connection joints in porous scaffolds for LT40 and could be eliminated by reducing the laser energy input.For thin wall parts,a large overhang angle or a small wall thickness resulted in porosity when a large layer thicknesses was used,and the porosity disappeared by reducing the layer thickness or laser energy input.A deeper keyhole penetration was found in all occasions with porosity,explaining the influence of layer thickness,geometrical structure,and laser energy input on the porosity.All the samples achieved a high fusion quality with a relative density of over 99.5%using the optimized laser energy input.The increased layer thickness resulted to more precipitation phases,finer grain sizes and decreased grain texture.With the similar high fusion quality,the tensile strength and elongation of bulk samples were significantly improved from 257 MPa and 1.41%with the 10μm layer to 287 MPa and 15.12%with the 40μm layer,in accordance with the microstructural change.The effect of layer thickness on the compressive properties of porous scaffolds was limited.However,the corrosion rate of bulk samples accelerated with increasing the layer thickness,mainly attributed to the increased number of precipitation phases.

关键词： Magnesium alloy WE43 Laser powder bed fusion Layer thickness Process optimization

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Pushing the high-k scalability limit with a superparaelectric gate layer

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Journal of Advanced Ceramics 2024年第4期13卷 539-547页

作者： Kun Wang Chao Liu Yuan Zhang Fuyu Lv Jun Ouyang Houbing Huang Rui-Long Yang Yu-Yao Zhao Hongbo Cheng Hanfei Zhu Xiaoming Shi yun tian Institute of Advanced Energy Materials and Chemistry Jinan Engineering Laboratory for Multi-scale Functional MaterialsSchool of Chemistry and Chemical EngineeringQilu University of Technology(Shandong Academy of Sciences)Jinan 250353China Key Laboratory for Liquid-Solid Structure Evolution and Processing of Materials(Ministry of Education) School of Materials Science and EngineeringShandong UniversityJinan 250061China China Tobacco Shandong Industrial Co. Ltd.Jinan 250104China Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Key Laboratory of Key Film Materials&Application for Equipments(Hunan Province) School of Material Sciences and EngineeringXiangtan UniversityXiangtan 411105China Advanced Research Institute of Multidisciplinary Science and School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education School of Chemistry and Materials ScienceShanxi Normal UniversityTaiyuan 030032China

To meet the expectation set by Moore’s law on transistors,the search for thickness-scalable high dielectric constant(k)gate layers has become an emergent research frontier.Previous investigations have failed to solve the“polarizability–scalability–insulation robustness”trilemma.In this work,we show that this trilemma can be solved by using a gate layer of a high k ferroelectric oxide in its superparaelectric(SPE)state.In the SPE,its polar order becomes local and is dispersed in an amorphous matrix with a crystalline size down to a few nanometers,leading to an excellent dimensional scalability and a good field-stability of the k value.As an example,a stable high k value(37±3)is shown in ultrathin SPE films of(Ba_(0.95),Sr_(0.05))(Zr_(0.2),Ti_(0.8))O_(3)deposited on LaNiO_(3)-buffered Pt/Ti/SiO_(2)/(100)Si down to a 4 nm thickness,leading to a small equivalent oxide thickness of~0.46 nm.The aforementioned characteristic microstructure endows the SPE film a high breakdown strength(~10.5 MV·cm^(−1)for the 4 nm film),and hence ensures a low leakage current for the operation of the complementary metal oxide semiconductor(CMOS)gate.Lastly,a high electrical fatigue resistance is displayed by the SPE films.These results reveal a great potential of superparaelectric materials as gate dielectrics in the next-generation microelectronics.

关键词： high-k transistors Moore's law superparaelectric insulation robustness

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Anesthesia,Anesthetics,and Postoperative Cognitive Dysfunction in Elderly Patients

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Current Medical Science 2024年第2期44卷 291-297页

作者： Hong-yu ZHU Jian-li YAN Min ZHANG tian-yun XU Chen CHEN Zhi-lin WU Department of Anesthesiology Linhe District People's HospitalBayannur 015000China Department of Neurosurgery Xinzhou District People's HospitalWuhan 430408China Department of Anesthesiology Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430022China

Postoperative cognitive dysfunction(POCD)remains a major issue that worsens the prognosis of elderly surgery patients.This article reviews the current research on the effect of different anesthesia methods and commonly utilized anesthetics on the incidence of POCD in elderly patients,aiming to provide an understanding of the underlying mechanisms contributing to this condition and facilitate the development of more reasonable anesthesia protocols,ultimately reducing the incidence of POCD in elderly surgery patients.

关键词： anesthesia anesthetics postoperative cognitive dysfunction elderly patients

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Machine learning promotes the development of all-solid-state batteries

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Chinese Journal of Structural Chemistry 2023年第9期42卷 83-94页

作者： Yong Qiu Xu Zhang yun tian Zhen Zhou Interdisciplinary Research Center for Sustainable Energy Science and Engineering(IRC4SE^(2)) School of Chemical Engineering Zhengzhou UniversityZhengzhou450001China

Lithium-ion batteries(LIBs)are a promising energy storage system for green energy applications.However,the use of liquid electrolytes in LIBs results in safety and lifespan issues.To address these challenges,researchers have been focusing on the development of all-solid-state batteries that use solid electrolytes.Unfortunately,traditional methods are time-consuming and expensive for exploring solid-state batteries,limiting their ability to keep up with growing social demand.In recent years,the development of big data has opened up new avenues for materials discovery,allowing for large-scale materials screening through computer simulations and machine learning models that can disclose the structure-activity relationship of materials.This review provides an overview of the basic procedures and common algorithms used in machine learning for designing solid-state batteries,with particular emphasis on recent research progress in applying machine learning to cathode materials and solid electrolytes,as well as predicting the condition of solid-state batteries.Additionally,this review offers a brief outlook on the challenges and opportunities facing machine learning methods in the realm of solid-state batteries.

关键词： Machine learning Solid-state batteries Performance prediction Big data

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Visual recognition of cardiac pathology based on 3D parametric model reconstruction

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Frontiers of Information Technology & Electronic Engineering 2022年第9期23卷 1324-1337页

作者： Jinxiao XIAO Yansong LI yun tian Dongrong Xu Penghui LI Shifeng ZHAO yunhe PAN School of Artificial Intelligence Beijing Normal UniversityBeijing100875China Department of Psychiatry Columbia University&New York State Psychiatric InstituteNew York10032USA College of Computer Science and Technology Zhejiang UniversityHangzhou310027China

Visual recognition of cardiac images is important for cardiac pathology diagnosis and treatment.Due to the limited availability of annotated datasets,traditional methods usually extract features directly from twodimensional slices of three-dimensional(3D)heart images,followed by pathological classification.This process may not ensure the overall anatomical consistency in 3D heart.A new method for classification of cardiac pathology is therefore proposed based on 3D parametric model reconstruction.First,3D heart models are reconstructed based on multiple 3D volumes of cardiac imaging data at the end-systole(ES)and end-diastole(ED)phases.Next,based on these reconstructed 3D hearts,3D parametric models are constructed through the statistical shape model(SSM),and then the heart data are augmented via the variation in shape parameters of one 3D parametric model with visual knowledge constraints.Finally,shape and motion features of 3D heart models across two phases are extracted to classify cardiac pathology.Comprehensive experiments on the automated cardiac diagnosis challenge(ACDC)dataset of the Statistical Atlases and Computational Modelling of the Heart(STACOM)workshop confirm the superior performance and efficiency of this proposed approach.

关键词： 3D visual knowledge 3D parametric model Cardiac pathology diagnosis Data augmentation

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High efficacy of tetra-PEG hydrogel sealants for sutureless dural closure

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Bioactive Materials 2022年第2期7卷 12-19页

作者： Tengjiao Zhu Hufei Wang Zehao Jing Daoyang Fan Zhongjun Liu Xing Wang yun tian Department of Orthopaedics Peking University Third HospitalBeijing100191China Beijing Key Laboratory of Spinal Disease Research Beijing100191China Engineering Research Center of Bone and Joint Precision Medicine Ministry of EducationBeijing100191China Beijing National Laboratory for Molecular Sciences Institute of ChemistryChinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing 100049China

Advances in meticulous dural closure technique remain a great challenge for watertight dural closure in the aged society,because the cerebrospinal fluid(CSF)leakage after spinal surgery is often accompanied with the disgusting wound infection,meningitis and pseudomeningocele.Here,a tetra-poly(ethylene glycol)(PEG)-based hydrogel sealant is developed with collective advantages of facile operation,high safety,quick set time,easy injectability,favorable mechanical strength and powerful tissue adhesion for effective sutureless dural closure during the surgery procedure.Impressively,this tetra-PEG sealant can instantaneously adhere to the irregular tissue surfaces even in a liquid environment,and effectively prevent or block off the intraoperative CSF leakage for sutureless dural closure and dura regeneration.Together,this sutureless tetra-PEG adhesive can be utilized as a very promising alternative for high-efficient watertight dural closure of the clinical patients who incidentally or deliberately undergo the durotomy during the spinal surgery.

关键词： CSF leakage Dural repair Watertight closure Sutureless Tetra-PEG hydrogel

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Enhanced multiple anchoring and catalytic conversion of polysulfides by SnO_(2)-decorated MoS_(2) hollow microspheres for high-performance lithium-sulfur batteries

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Journal of Materials Science & Technology 2022年第5期100卷 216-223页

作者： yun tian Zhengyu Wei Fan Li Songjie Li Lixiang Shao Mengyuan He Panfei Sun Yuanyuan Li School of Chemical Engineering Zhengzhou UniversityZhengzhou 450001China Engineering Research Center of Advanced Functional Material Manufacturing of Ministry of Education Zhengzhou UniversityZhengzhou 450001China

Lithium-Sulfur(Li-S)batteries are very competitive in energy storage equipment due to their high theoretical capacity and low cost of raw materials.However,the serious polysulfide"shuttle effect",volume expansion effect and slow conversion reaction kinetics of Li-S batteries during the charge/discharge cycle process still need to be resolved urgently.Herein,we prepared a novel sulfur host of SnO_(2)-decorated MoS_(2) hollow microspheres(SnO_(2)-MoS_(2) HMSs).The unique hollow structure provides enough space to accommodate a large amount of sulfur and effectively adapts to its large volume expansion during charge and discharge process.On the other hand,the SnO_(2) nanoparticles that attached to the surface of the MoS_(2) nanosheets will accelerate the catalysis of MoS_(2) and enhance the bonding strength with the polysulfide intermediates through the S-Sn-O chemical bond,which further inhibits the shuttle effect.The newly synthesized SnO_(2)-MoS_(2) HMSs cathode has achieved excellent electrochemical performance.The initial discharge specific capacity of 1326.4 mAh g^(-1) was obtained at 0.2 C,and after 100 cycles,the specific capacity of the SnO_(2)-MoS_(2) HMSs/S cathode only decreased slightly to 1183.8 mAh g^(-1),its capacity retention rate reaching as high as 89.2%.We expect the newly synthesized hollow structured MoS_(2) with SnO_(2) decoration provides a new strategy for the construction of Li-S battery cathode materials.

关键词： Li-S batteries SnO_(2)-decorated hollow MoS_(2)microspheres S-Sn-O chemical bond Electrochemical performance

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Panoramic Insights into Microevolution and Macroevolution of A Prevotella copri-containing Lineage in Primate Guts

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Genomics, Proteomics & Bioinformatics 2022年第2期20卷 334-349页

作者： Hao Li Jan P.Meier-Kolthoff Canxin Hu Zhongjie Wang Jun Zhu Wei Zheng yun tian Feng Guo School of Life Sciences Xiamen UniversityXiamen 361102China Department of Bioinformatics Leibniz Institute DSMZ–German Collection of Microorganisms and Cell CulturesD-38124 BraunschweigGermany Fujian Provincial Universities Key Laboratory of Microbial Resource Xiamen UniversityXiamen 361102China

Prevotella copri and its related taxa are widely detected in mammalian gut microbiomes and have been linked with an enterotype in humans.However,their microevolution and macroevolution among hosts are poorly characterized.In this study,extensively collected marker genes and genomes were analyzed to trace their evolutionary history,host specificity,and biogeographic distribution.Investigations based on marker genes and genomes suggest that a P.copri-containing lineage(PCL)harbors diverse species in higher primates.Firstly,P.copri in the human gut consisted of multiple groups exhibiting high genomic divergence and conspicuous but non-strict biogeographic patterns.Most African strains with high genomic divergence from other strains were phylogenetically located at the root of the species,indicating the co-evolutionary history of P.copri and Homo sapiens.Secondly,although long-term co-evolution between PCL and higher primates was revealed,sporadic signals of co-speciation and extensive host jumping of PCL members were suggested among higher primates.Metagenomic and phylogenetic analyses indicated that P.copri and other PCL species found in domesticated mammals had been recently transmitted from humans.Thirdly,strong evidence was found on the extensively horizontal transfer of genes(e.g.,genes encoding carbohydrate-active enzymes)among sympatric P.copri groups and PCL species in the same primate host.Our study provides panoramic insights into the combined effects of vertical and horizontal transmission,as well as potential niche adaptation,on the microevolutionary and macroevolutionary history for an enterotyperepresentative lineage.

关键词： Prevotella copri Co-speciation Gut microbiome Host Biogeography

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Association of Human Whole-blood NAD+Levels with Nabothian Cyst

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Biomedical and Environmental Sciences 2024年第5期37卷 471-478页

作者： XU Ling WANG Yue Xuan WANG Wei FAN Xue CHEN Xue Yu ZHOU tian yun LIU Yu He YU Ye YANG Fan JU Zhen Yu ZHOU Yong WANG Deng Liang Clinical Research Institute Shanghai General HospitalShanghai Jiao Tong University School of MedicineShanghai 200080China NHC Key Lab of Reproduction Regulation Shanghai Engineering Research Center of Reproductive Health Drugs and DevicesShanghai Institute for Biomedical and Pharmaceutical TechnologiesShanghai 200237China Department of Applied Statistics Johannes Kepler University LinzLinz 4040Austria Hematology Center Beijing Key Laboratory of Pediatric Hematology OncologyNational Key Discipline of Pediatrics(Capital Medical University)Key Laboratory of Major Diseases in ChildrenMinistry of EducationBeijing Children's HospitalCapital Medical UniversityNational Center for Children's HealthBeijing 100045China Department of Biostatistics School of Public HealthCheeloo College of MedicineShandong UniversityJinan 250012ShandongChina Clinical Medicine School of Basic MedicineShanghai Medical College Fudan UniversityShanghai 200032China Department of Biochemistry and Molecular Biology Hengyang Medical SchoolUniversity of South ChinaHengyang 421001HunanChina Administrative Office Total Quality Management OfficeTotal Quality Management InstituteShanghai General HospitalShanghai Jiao Tong University School of MedicineShanghai 200080China The First Affiliated Hospital of Jinan University Institute of Aging and Regenerative MedicineJinan UniversityJinan 510632GuangzhouChina Department of Scientific Research The First Affiliated Hospital of Huzhou UniversityHuzhou 313000ZhejiangChina Department of Neurosurgery Neurosurgery Research InstituteThe First Affiliated HospitalFujian Medical UniversityFuzhou 350005FujianChina Department of Neurosurgery Binhai Branch of National Regional Medical CenterThe First Affiliated HospitalFujian Medical UniversityFuzhou 350209FujianChina Fujian Provincial Institutes of Brain Disorders and Brain Sciences The First Affiliated HospitalFujian Medical UniversityFuzhou 350005FujianChina Fujian Provincial Clinical Research Center for Neurological

Objective Little is known about the association between whole-blood nicotinamide adenine dinucleotide(NAD^(+))levels and nabothian cysts.This study aimed to assess the association between NAD^(+)levels and nabothian cysts in healthy Chinese women.Methods Multivariate logistic regression analysis was performed to analyze the association between NAD^(+)levels and nabothian cysts.Results The mean age was 43.0±11.5 years,and the mean level of NAD^(+)was 31.3±5.3μmol/L.Nabothian cysts occurred in 184(27.7%)participants,with single and multiple cysts in 100(15.0%)and84(12.6%)participants,respectively.The total nabothian cyst prevalence gradually decreased from37.4%to 21.6%from Q1 to Q4 of NAD^(+)and the prevalence of single and multiple nabothian cysts also decreased across the NAD^(+)quartiles.As compared with the highest NAD^(+)quartile(≥34.4μmol/L),the adjusted odds ratios with 95%confidence interval of the NAD^(+)Q1 was 1.89(1.14–3.14)for total nabothian cysts.The risk of total and single nabothian cysts linearly decreased with increasing NAD^(+)levels,while the risk of multiple nabothian cysts decreased more rapidly at NAD^(+)levels of 28.0 to35.0μmol/L.Conclusion:Low NAD^(+)levels were associated with an increased risk of total and multiple nabothian cysts.

关键词： Nicotinamide adenine dinucleotide Nabothian cyst Female Risk factor

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