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Investigation of role of cartilage surface polymer brush border in lubrication of biological joints

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Friction 2022年第1期10卷 110-127页

作者： JinJing LIAO David W.SMITH Saeed MIRAMINI Bruce S.GARDINER Lihai ZHANG Department of Infrastructure Engineering.The University of Melbourne.Victoria 3010 Australia Faculty of Engineering and Mathematical Sciences The University of Western AustraliaWA 6009Australia College of Science Health.Engineering and Education.Murdoch UniversityWA 6150Australia

Although experimental evidence has suggested that the polymer brush border(PBB)on the cartilage surface is important in regulating fluid permeability in the contact gap,the current theoretical understanding of joint lubrication is still *** address this research gap,a multiscale cartilage contact model that includes PBB,in particular its effect on the fluid permeability of the contact gap,is developed in this *** modeling is employed to estimate the permeability of the contact *** permeability is classified into two categories:For a gap size>1μm,the flow resistance is assumed to be dominated by the cartilage roughness;for gap size<1μm,flow resistance is assumed to be dominated by the surface polymers extending beyond the collagen network of the articular *** gap sizes of less than 1μm,the gap permeability decreases exponentially with increasing aggrecan concentration,whereas the aggrecan concentration varies inversely with the gap ***,the gap permeability is employed in a macroscale cartilage contact model,in which both the contact gap space and articular cartilage are modeled as two interacting poroelastic *** fluid exchange between these two media is achieved by imposing pressure and normal flux continuity boundary *** model results suggest that PBB can substantially enhance cartilage lubrication by increasing the gap fluid load support(e.g.,by 26 times after a 20-min indentation compared with the test model without a PBB).Additionally,the fluid flow resistance of PBB sustains the cartilage interstitial fluid pressure for a relatively long period,and hence reduces the vertical deformation of the ***,it can be inferred that a reduction in the PBB thickness impairs cartilage lubrication ability.

关键词： assumed polymer hence

Unveiling strain-enhanced moiréexciton localization in twisted van der Waals homostructures

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Nano research 2024年第4期17卷 3245-3252页

作者： Henry Rui He Haihong Zheng Biao Wu Shaofei Li Junnan Ding Zongwen Liu Jian-Tao Wang Anlian Pan Yanping Liu Institute of Quantum Physics School of PhysicsCentral South UniversityChangsha 410083China State Key Laboratory of Precision Manufacturing for Extreme Service Performance Central South UniversityChangsha 410083China School of Chemical and Biomolecular Engineering The University of SydneyNSW 2006Australia Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China College of Materials Science and Engineering Hunan UniversityChangsha 410082China State Key Laboratory of High-Performance Complex Manufacturing Central South UniversityChangsha 410083China Shenzhen research Institute of Central South University Shenzhen 51800China

Moirésuperlattices,arising from the controlled twisting of van der Waals homostructures at specific angles,have emerged as a promising platform for quantum emission ***,the manipulation of strain provides a versatile strategy to finely adjust electronic band structures,enhance exciton luminescence efficiency,and establish a robust foundation for two-dimensional quantum light ***,the intricate interplay between strain and moirépotential remains partially ***,we introduce a meticulously designed fusion of strain engineering and the twisted 2L-WSe_(2)/2L-WSe_(2) homobilayers,resulting in the precise localization of moiré*** low-temperature photoluminescence spectroscopy,we unveil the emergence of highly localized moiré-enhanced emission,characterized by the presence of multiple distinct emission ***,our investigation demonstrates the effective regulation of moirépotential depths through strain engineering,with the potential depths of strained and unstrained regions differing by 91%.By combining both experimental and theoretical approaches,our study elucidates the complex relationship between strain and moirépotential,thereby opening avenues for generating strain-induced moiréexciton single-photon sources.

关键词： moirésuperlattices strain engineering moiréexcitons moirépotential

Temperature-Dependent Mechanical Properties of Graphene/Cu Nanocomposites with In-Plane Negative Poisson’s Ratios

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research 2020年第1期2020卷 902-913页

作者： Yin Fan Yang Xiang Hui-Shen Shen School of Engineering Western Sydney UniversityLocked Bag 1797PenrithNSW 2751Australia School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China School of Ocean and Civil Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Negative Poisson’s ratio(NPR),also known as“auxetic”,is a highly desired property in a wide range of future industry *** employing molecular dynamics(MD)simulation,metal matrix nanocomposites reinforced by graphene sheets are studied in this *** the simulation,single crystal copper with crystal orientation絵110is selected as the matrix and an embeddedatom method(EAM)potential is used to describe the interaction of copper *** aligned graphene sheet is selected as reinforcement,and a hybrid potential,namely,the Erhart-Albe potential,is used for the interaction between a pair of carbon *** interaction between the carbon atom and copper atom is approximated by the Lennard-Jones(L-J)*** simulation results showed that both graphene and copper matrix possess in-plane *** temperature-dependent mechanical properties of graphene/copper nanocomposites with in-plane NPRs are obtained for the first time.

关键词： composites copper interaction

Impact characteristics and stagnation formation on a solid surface by a supersonic abrasive waterjet

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International Journal of Extreme Manufacturing 2019年第4期1卷 43-61页

作者： Kunlapat Thongkaew Jun Wang Guan Heng Yeoh School of Mechanical and Manufacturing Engineering UNSW Sydney(The University of New South Wales)NSW 2052Australia

A computational fluid dynamics(CFD)study of the impact characteristics and stagnation formation on a solid target surface by an abrasive waterjet at supersonic velocities is presented to understand the impact process.A CFD model is developed and verified by experimental water and particle velocities and then used to simulate the jet impact *** trends of the stagnation formation and its effect on the jet flow with respect to the jetting and impacting parameters are amply *** is found that stagnation formation at the impact site increases with an increase in the impact time,nozzle standoff distance and nozzle diameter,while the initial peak velocity at the nozzle exit has little effect on the size of the stagnation *** is shown that stagnation markedly changes the water and particle flow direction,so that the particle impact angle is varied and the jet impact area is *** jet structure may be classified to have a free jet flow region,a jet deflection region with a stagnation zone and a wall jet ***,the stagnation affects significantly the waterjet and particle energy transferred to the target *** average particle velocity across the jet is reduced by approximately one third due to the damping effect of the stagnation under the conditions considered in this study.

关键词： abrasive waterjet jet impingement particle velocity flow characteristics impact phenomenon stagnation

Structure and quality controlled growth of InAs nanowires through catalyst engineering

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Nano research 2014年第11期7卷 1640-1649页

作者： ZhiZhang Zhenyu Lu Hongyi Xu Pingping Chen Wei Lu Jin Zou Materials Engineering The University of Queensland St. Lucia Queensland 4072 Australia National Laboratory for Infrared Physics Shanghai Institute of Technical Physics Chinese Academy of Sciences 500 Yu-Tian Road Shanghai 200083 China Centre for Microscopy and Microanalysis The University of Queensland St. Lucia Queensland 4072 Australia

In this study, the structure and quality controlled growth of InAs nanowires using Au catalysts in a molecular beam epitaxy reactor is presented. By tuning the indium concentration in the catalyst, defect-free wurtzite structure and defect-free zinc blende structure InAs nanowires can be induced. It is found that these defect-free zinc blende structure InAs nanowires grow along 〈110〉 directions with four low-energy {111} and two {110} side-wall facets and adopt the （111） catalyst/nanowire interface. Our structural and chemical characterization and calculations identify the existence of a catalyst supersaturation threshold for the InAs nanowire growth. When the In concentration in the catalyst is sufficiently high, defect-free zinc blende structure InAs nanowires can be induced. This study provides an insight into the manipulation of crystal structure and structure quality of III-V semiconductor nanowires through catalyst engineering.

关键词： structure quality InAs nanowires molecular beam epitaxy (MBE) Au catalysts

Oxidative stress physiology in relation to life history traits of a free-living vertebrate:the spotted snow skink,Niveoscincus ocellatus

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Integrative Zoology 2011年第2期6卷 140-149页

作者： Caroline ISAKSSON Geoffrey M.WHILE Mats OLSSON Jan KOMDEUR Erik WAPSTRA University of Groningen Animal Ecology GroupHarenThe Netherlands University of Wollongong School of Biological SciencesWollongongNew South Wales University of Tasmania School of ZoologyHobartTasmaniaAustralia

Recent research suggests that oxidative stress,via its links to metabolism and senescence,is a key mechanism linking life history traits such as fecundity and growth with survival;however,this has rarely been put under empirical scrutiny within free-living *** a wild population of live-bearing skinks,we explored how plasma antioxidant activity(OXY),reactive oxidative metabolites(ROM),and the estimated oxidative stress index are associated with female and male life *** found that male skinks have a significantly higher ROM and estimated oxidative stress index than female skinks,but this was not accompanied by a sex difference in *** sexes showed a non-linear association between OXY and age,indicating that the oldest and youngest individuals had the lowest ***,female skinks with high OXY showed a decreased probability of survival to the following ***,we found no significant associations between female reproductive investment(litter size or litter mass)or parturition date(***)and oxidative ***,our results offer mixed support for a role of oxidative stress in mediating life history traits and suggest that future studies need to explore oxidative stress during vitellogenesis in addition to using an intra-individual approach to understand the cost of reproduction and patterns of aging.

关键词： antioxidants life history Niveoscincus ocellatus oxidative stress reptile

Concentration-Dependent Solar Thermochemical CO_(2)/H_(2)O Splitting Performance by Vanadia-Ceria Multiphase Metal Oxide Systems

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research 2020年第1期2020卷 522-533页

作者： Asim Riaz Muhammad Umair Ali T.Gabriel Enge Takuya Tsuzuki Adrian Lowe Wojciech Lipinski research School of Electrical Energy and Materials EngineeringThe Australian National UniversityCanberra ACT 2601Australia Department of Materials Science and Engineering College of EngineeringPeking UniversityBeijing 100871China research School of Earth Sciences The Australian National UniversityCanberra ACT 2601Australia

The effects of V and Ce concentrations(each varying in the 0-100%range)in vanadia-ceria multiphase systems are investigated for synthesis gas production via thermochemical redox cycles of CO_(2) and H_(2)O splitting coupled to methane partial oxidation *** oxidation of prepared oxygen carriers is performed by separate and sequential CO_(2) and H_(2)O splitting *** and chemical analyses of the mixed-metal oxides revealed important information about the Ce and V interactions affecting their crystal phases and redox *** CeO_(2) and pure V_(2)O_(5) are found to offer the lowest and highest oxygen exchange capacities and syngas production performance,*** mixed-oxide systems provide a balanced performance:their oxygen exchange capacity is up to 5 times higher than that of pure CeO_(2) while decreasing the extent of methane *** addition of 25%V to CeO_(2) results in an optimum mixture of CeO_(2) and CeVO4 for enhanced CO_(2) and H_(2)O *** higher V concentrations,cyclic carbide formation and oxidation result in a syngas yield higher than that for pure CeO_(2).

关键词： pure methane splitting

Length-based separation of Bacillus subtilis bacterial populations by viscoelastic microfluidics

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Microsystems & Nanoengineering 2022年第1期8卷 149-159页

作者： Ping Liu Hangrui Liu Lucie Semenec Dan Yuan Sheng Yan Amy K.Cain Ming Li Suqian University Suqian 223800China School of Engineering Macquarie UniversitySydneyNSW 2109Australia Department of Physics and Astronomy Macquarie UniversitySydneyNSW 2109Australia ARC Centre of Excellence in Synthetic Biology Department of Molecular ScienceMacquarie UniversitySydneyNSW 2109Australia Centre for Regional and Rural Futures Deakin UniversityGeelongVIC 3216Australia Institute for Advanced study Shenzhen UniversityShenzhen 518060China Biomolecular Discovery research Centre Macquarie UniversitySydneyNSW 2109Australia

In this study,we demonstrated the label-free continuous separation and enrichment of Bacillus subtilis populations based on length using viscoelastic ***,a gram-positive,rod-shaped bacterium,has been widely used as a model organism and an industrial *** can be arranged in different morphological forms,such as single rods,chains,and clumps,which reflect differences in cell types,phases of growth,genetic variation,and changing environmental *** ability to prepare *** populations with a uniform length is important for basic biological studies and efficient industrial ***,we systematically investigated how flow rate ratio,poly(ethylene oxide)(PEO)concentration,and channel length affected the length-based separation of *** *** lateral positions of *** cells with varying morphologies in a straight rectangular microchannel were found to be dependent on cell length under the co-flow of viscoelastic and Newtonian ***,we evaluated the ability of the viscoelastic microfluidic device to separate the two groups of *** cells by length(i.e.,1-5μm and>5μm)in terms of extraction purity(EP),extraction yield(EY),and enrichment factor(EF)and confirmed that the device could separate heterogeneous populations of bacteria using elasto-inertial effects.

关键词： viscoelastic separation straight

Element diffusion ability in metasomatic agents and its effect on chemical characteristics of metasomatized peridotites

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Science China Earth Sciences 2006年第9期49卷 926-937页

作者： Y S O’Reilly GEMOC ARC National Key Centre Department of Earth and Planetary Sciences Macquarie University Sydney N.S.W. 2109 Australia

Detailed in situ LM-ICPMS researches on the composite xenoliths from Yingfengling volcano of Leizhou Peninsula, South China, indicate that most incompatible trace elements of clino- pyroxenes in composite xenoliths decrease spatially from pyroxenites to distal lherzolites, and com- patible elements and HREE increase steeply. The increasing and decreasing rate is distinct for dif- ferent trace elements, which give rise to element chromatographic fractionation within metasomatized lherzolites. The element chromatographic fractionation result actually from the difference in element diffusive rate in melts or fluids percolating through wall-rock lherzolites. Based on element variation profiles in composite xenoliths this study indicates that Sr, Nb, La and Ce have the highest diffusive mobility, MREE-HREE are moderate, and Zr, Hf, Ti, Ga and Sc are very low in most cases. Higher diffusive rates of LREE than HREE would enlarge the REE fractionation of metasomatized peridotites, and lower diffusive rate of Zr, Hf and Ti relative to neighbor REEs with similar incompatibility would cause the relative depletion of these elements in metasomatized peridotites. Trace elements com- monly have a higher diffusive rate in fluid-rich infiltrating melt, which will weaken element chroma- tographic fractionation during the metasomatism. The range of mantle metasomatism caused by sili- cate melt intrusion is very limited, generally within tens of centimeters wide. The width of metasoma- tized wall-rock peridotites near the pyroxenite or horblendite veins was strictly controlled by both melt volume and chemical characteristics.

关键词： composite xenolith, metasomatism, chromatographic fractionation, diffusive rate, Leizhou Peninsula.