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Thrombogenicity of biodegradable metals

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Bioactive Materials 2024年第8期38卷 411-421页

作者： D.E.j.Anderson h.h.Le h.Vu j.johnson j.E.Aslan j.Goldman M.T.hinds Department of Biomedical Engineering Oregon Health&Science UniversityPortlandORUSA Knight Cardiovascular Institute Oregon Health&Science UniversityPortlandORUSA Department of Biomedical Engineering Michigan Technological UniversityHoughtonMIUSA

Biodegradable metals offer a promising means to ameliorate many of the long-term risks associated with vascular devices made of conventional biostable stent *** numerous biodegradable metal alloys have been developed and characterized in animal models,knowledge of their blood reactivity and thrombogenicity remains *** hemocompatibility is particularly valuable because current generation drug-eluting stents pose a significant long-term thrombosis *** this study,four pure metals,widely used as degradable base materials(Fe,Zn,Mg,and Mo),and three alloys commonly used in cardiovascular devices[NiTi,CoCr,and stainless steel(SS)]were *** work examined how each of these metals activate platelets,coagulation factors,and inflammation using in vitro hemocompatibility assays and a clinically relevant ex vivo non-human primate arteriovenous shunt *** found that while all metals promoted a downstream activation of platelets and coagulation in flowing whole blood,platelet and fibrin attachment to Mg was markedly ***,Fe and Mo trended toward higher platelet attachment and contact pathway ***,the results suggest that Mg may delay clot initiation,but not eliminate clot formation,indicating the importance of understanding thrombosis in Mg alloys that are currently being developed for clinical use as biodegradable stents.

关键词： Vascular stents Biodegradable metals Thrombosis Contact pathway Platelets

A PARAMETER-UNIFORM TAILORED FINITE POINT METhOD FOR SINGULARLY PERTURBED LINEAR ODE SYSTEMS＊

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journal of Computational Mathematics 2013年第4期31卷 422-438页

作者： houde han j.j.h. Miller Min Tang Department of Mathematical Sciences Tsinghua University Beijing 100084 China Department of Mathematics Trinity College Dublin 2 Ireland Key Laboratory of Scientific and Engineering Computing Department of Mathematics and Institute of Natural Sciences Shanghai Jiao Tong University Shanghai 200240 China

In scientific applications from plasma to chemical kinetics, a wide range of temporal scales can present in a system of differential equations. A major difficulty is encountered due to the stiffness of the system and it is required to develop fast numerical schemes that are able to access previously unattainable parameter regimes. In this work, we consider an initial-final value problem for a multi-scale singularly perturbed system of linear ordi- nary differential equations with discontinuous coefficients. We construct a tailored finite point method, which yields approximate solutions that converge in the maximum norm, uniformly with respect to the singular perturbation parameters, to the exact solution. A parameter-uniform error estimate in the maximum norm is also proved. The results of numerical experiments, that support the theoretical results, are reported.

关键词： Tailored finite point method Parameter uniform Singular perturbation ODEsystem.

Manipulation of Crawling Growth for the Formation of Sub-millimeter Long ZnO Nanowalls

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journal of Materials Science & Technology 2008年第4期24卷 589-593页

作者： h.j.FAN M.Zacharias Department of Earth Sciences University of Cambridge U.K. Faculty of Applied Science Albert-Ludwigs-University Freiburg Germany Formerly at： Max Planck Institute of Microstructure Physics Halle Germany

Vapor-phase growth of ZnO nanowires based on gold catalyst is usually accompanied with lateral crawling growth on the substrate surface. We present results from our systematic experiments where the growth temperature and catalyst size are controlled. The data corroborate that it is possible to obtain clean vertical nanowire arrays while avoiding the crawling growth. 0% the other hand, crawling growth can be manipulated to obtain root-interconnected nanowire arrays, which could be useful for certain applications. Our results also imply that the previously suggested growth mechanism for the wire-on-wall hybridstructure might be incorrect. Finally, we show the formation of sub-millimeter long, straight ZnO nanowalls by combining a gold-catalyzed epitaxial growth of vertical nanowires and their mergence due to a confined crawling growth. These unconventional nanostructures might have unique electric or optical transport properties.

关键词： Nanowire Nanowall ZnO Crawling growth

A novel approach to determine residual stress field during FSW of AZ91 Mg alloy using combined smoothed particle hydrodynamics/neuro-fuzzy computations and ultrasonic testing

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journal of Magnesium and Alloys 2021年第4期9卷 1311-1335页

作者： A.R.Eivani h.Vafaeenezhad h.R.jafarian j.Zhou School of metallurgy and materials engineering iran university of science and technology^nartnaktehraniran department of biomechanical engineering delft university of technologymekehveg 22628 cd delftthe netherlands

The faults in welding design and process every so often yield defective parts during friction stir welding(FSW).The development of numerical approaches including the finite element method(FEM)provides a way to draw a process paradigm before any physical *** is not practical to simulate all possible designs to identify the optimal FSW practice due to the inefficiency associated with concurrent modeling of material flow and heat dissipation throughout the *** study intends to develop a computational workflow based on the mesh-free FEM framework named smoothed particle hydrodynamics(SPh)which was integrated with adaptive neuro-fiizzy inference system(ANFIS)to evaluate the residual stress in the FSW *** integrated SPh and ANFIS methodology was established and the well-trained ANIS was then used to predict how the FSW process depends on its *** verify the SPh calculation,an itemized FSW case was performed on AZ91 Mg alloy and the induced residual stress was measured by ultrasonic *** suggested methodology can efficiently predict the residual stress distribution throughout friction stir welding of AZ91 alloy.

关键词： Friction stir welding(FSW) Smoothed particle hydrodynamics(SPh) Adaptive neuro-fuzzy inference system(ANFIS) Ultrasonic Residual stress

Observation of Rotational Bands in Neutron—Rich ^106Mo Nucleus

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Chinese Physics Letters 2002年第2期19卷 180-183页

作者：许瑞清 j.h.hamilton DepartmentofPhysics TsinghuaUniversityBeijing100084 DepartmentofPhysics VanderbiltUniversityNashvilleTN37235USA

The rotational bands up to a spin of 16h in the neutron-rich ^106Mo nucleus have been investigated by measuring high-fold prompt γ-ray coincidence events following spontaneous fission of 252Cf with a Gammasphere detector array. The ground-state band, the one-phonon and two-phonon γ-vibrational bands, as well as a quasi-particle band have been confirmed and expanded. The other four collective rotational bands, three proposed as two-quasi-particle bands and one proposed as a β-vibrational band, have been newly observed. The characteristics of these collective bands and the possible configurations for the quasi-particle bands are discussed.

关键词： Gamma rays

^3PF2 neutron superfluidity in neutron stars and three-body force effect

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Chinese Physics B 2008年第9期17卷 3289-3293页

作者：崔常喜左维 h.j.Schulze Institute of Modern Physics Chinese Academy of Sciences INFN Sezione di Catania

We investigate the ^3PF2 neutron superfluidity in h-stable neutron star matter and neutron stars by using the BCS theory and the Brueckner-hartree-Fock approach. We adopt the Argonne V18 potential supplemented with a microscopic three-body force as the realistic nucleon-nucleon interaction. We have concentrated on studying the threebody force effect on the ^3PF2 neutron pairing gap. It is found that the three-body force effect is to enhance remarkably the ^3PF2 neutron superfluidity in neutron star matter and neutron stars.

关键词： ^3PF2 superfluidity neutron star three-body force Brueckner-hartree-Fock approach

hardness-thermal stability synergy in nanograined Ni and Ni alloys:Superposition of nanotwin and low-energy columnar boundary

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journal of Materials Science & Technology 2023年第6期137卷 123-131页

作者： F.h.Duan Y.Lin Q.Li j.h.Luan j.Lu j.Pan Y.Li Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Laboratory of Nanomaterials&Nanomechanics Department of Mechanical EngineeringCity University of Hong KongHong KongChina State Key Laboratory of Material Processing and Die&Mould Technology and School of Materials Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China Department of Materials Science and Engineering City University of Hong KongHong KongChina Centre for Advanced Structural Materials Greater Bay Joint DivisionShenyang National Laboratory for Materials ScienceCity University of Hong Kong Shenzhen Research InstituteShenzhen 518057China City U-Shenzhen Futian Research Institute Shenzhen 518045China

Refining grains into nanoscale can significantly strengthen and harden metallic materials;however,nanograined metals generally exhibit low thermal stability,hindering their practical *** this work,we exploit the superposition of the contribution of nanotwins,low-angle grain boundaries,and microalloying to tailor superior combinations of high hardness and good thermal stability in Ni and Ni *** the nanotwinned Ni having a twin thickness of∼2.9 nm and grain size of 28 nm,it exhibits a hardness over 8.0 GPa and an onset coarsening temperature of 623 K,both of which are well above those of nanograined ***/Mo microalloying can further improve the onset coarsening temperature to 773 K without comprising *** analyses reveal that high hardness is achieved via strengthen-ing offered by extremely fine ***,the superior thermal stability is mainly ascribed to the low driving force for grain growth induced by the low-angle columnar boundary architecture and to the additional pinning effect on the migration of twin/columnar boundaries provided by minor Re/Mo *** present work not only reveals a family of nanotwinned metals possessing the combination of ultra-high hardness and high thermal stability but also provides a strategy for tailoring properties of metallic materials by pairing low-angle grain boundaries and twin boundaries.

关键词： Nanotwin Thermal stability hardness Low-angle grain boundary Microalloying

Macroscopic and microscopic mechanical behaviors of climbing tendrils

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Acta Mechanica Sinica 2019年第3期35卷 702-710页

作者： Q.Guo j.j.Dong Y.Liu X.h.Xu Q.h.Qin j.S.Wang Tianjin Key Laboratory of Modern Engineering Mechanics Department of MechanicsTianjin UniversityTianjin 300054China State Key Laboratory of Nonlinear Mechanics (LNM) Institute of MechanicsChinese Academy of ScienceBeijing 100080China Research School of Engineering Australian National UniversityCanberraACT 2601Australia

Tendril-bearing climbing plants must recur to the tendril helices with chiral perversion or dual chirality for climbing and to obtain sun exposure. Despite researchers' prolonged fascination with climbing tendrils since Darwin's time and even earlier, why the soft and slender tendrils can bear heavy loads such as the self-weight of a plant or additional load caused by rain remains elusive. In this paper, we take towel gourd tendrils as an example and investigate the macroscopic and microscopic mechanical behaviors of tendrils through experiments and simulations. Our study indicates that the tendril filament exhibits rubber-like hyperelastic behaviors and can particularly endure large elongation, which is mainly attributed to the superelasticity of the cellulose fibril helix contained in the cell wall. Combination of the tendril helical structure with dual chirality or chiral perversion at a macroscale and a cellulose filament helix at a subcellular level creates superior elasticity for biological species relying on support and climbing. This study provides deep insight into the structure-property relationship of climbing tendrils, and the relationship is useful for the bioinspired design of composite systems with superior elasticity.

关键词： Climbing tendril Mechanical behaviors Structure-property relationship Large elongation

Biological transformation,kinetics and dose-response assessments of bound musk ketone hemoglobin adducts in rainbow trout as biomarkers of environmental exposure

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journal of Environmental Sciences 2008年第7期20卷 878-884页

作者： M A Mottaleb j h Zimmerman T W Moy Department of Chemistry and Biochemistry Baylor UniversityP.O.Box 97348WacoTX 76798USA. U.S.Environmental Protection Agency National Exposure Research LaboratoryEnvironmental Sciences Division944 East Harmon AveLas VegasNV 89119USA

Low levels (ng/g) of musk ketone (MK),used as a fragrance additive in the formulation of personal care products,are frequently detected in the water and other ***,aquatic organisms can be continuously exposed to *** this study,kinetics and dose-response assessments of 2-amino-MK (AMK) metabolite,bound to cysteine-hemoglobin (hb) in rainbow trout,formed by enzymatic nitro-reduction of MK have been *** were exposed to a single exposure of 0.010,0.030,0.10,and 0.30 mg MK/g ***...

关键词： biotransformation kinetics hemoglobin adducts dose-response nitro musks biomarker fish