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Impact of scandium and terbium on the mechanical properties,corrosion behavior,and biocompatibility of biodegradable Mg-Zn-Zr-Mn alloys

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Journal of Magnesium and Alloys 2024年第2期12卷 546-572页

作者： Khurram Munir Jixing Lin Xian Tong arne Biesiekierski Yuncang Li Cuie Wen School of Engineering RMIT UniversityMelbourneVictoria 3001Australia School and Hospital of Stomatology Wenzhou Medical UniversityWenzhou 325027China

Magnesium(Mg)-based bone implants degrade rapidly in the physiological environment of the human body which affects their structural integrity and biocompatibility before adequate bone *** earth elements(REEs)have demonstrated their effectiveness in tailoring the corrosion and mechanical behavior of Mg *** study methodically investigated the impacts of scandium(Sc)and terbium(Tb)in tailoring the corrosion resistance,mechanical properties,and biocompatibility of Mg–0.5Zn–0.35Zr–0.15Mn(MZZM)alloys fabricated via casting and hot *** indicate that addition of Sc and Tb improved the strength of MZZM alloys via grain size reduction and solid solution strengthening *** extruded MZZM–(1–2)Sc–(1–2)Tb(wt.%)alloys exhibit compressive strengths within the range of 336–405 MPa,surpassing the minimum required strength of 200 MPa for bone implants by a significant *** polarization tests revealed low corrosion rates of as–cast MZZM(0.25 mm/y),MZZM–2Tb(0.45 mm/y),MZZM–1Sc–1Tb(0.18 mm/y),and MZZM–1Sc–2Tb(0.64 mm/y),and extruded MZZM(0.17 mm/y),MZZM–1Sc(0.15 mm/y),MZZM-2Sc(0.45 mm/y),MZZM-1Tb(0.17 mm/y),MZZM-2Tb(0.10 mm/y),MZZM–1Sc-1Tb(0.14 mm/y),MZZM-1Sc-2Tb(0.40 mm/y),and MZZM–2Sc–2Tb(0.51 mm/y)alloys,which were found lower compared to corrosion rate of high-purity Mg(~1.0 mm/y)reported in the ***,addition of Sc,or Tb,or Sc and Tb to MZZM alloys did not adversely affect the viability of SaOS2 cells,but enhanced their initial cell attachment,proliferation,and spreading shown via polygonal shapes and *** study emphasizes the benefits of incorporating Sc and Tb elements in MZZM alloys,as they effectively enhance corrosion resistance,mechanical properties,and biocompatibility simultaneously.

关键词： Corrosion property In vitro cytotoxicity Magnesium alloys Mechanical property Rare earth elements

Elevated fluid and glycosaminoglycan content in the Achilles tendon contribute to higher intratendinous pressures:Implications for Achilles tendinopathy

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Journal of Sport and Health Science 2024年第6期13卷 863-871页

作者： Lauren Pringels Gert-Jan Van Valckenborgh Patrick Segers Amelie Chevalier Hedwig Stepman Evi Wezenbeek arne Burssens Luc Vanden Bossche Department of Physical and Rehabilitation Medicine Ghent University HospitalGhent 9000Belgium Department of Rehabilitation Sciences and Physiotherapy Ghent UniversityGhent 9000Belgium Department of Electronics and Information Systems Ghent UniversityGhent 9000Belgium Department of Electromechanics University of AntwerpAntwerp 2020Belgium Department of Laboratory Medicine Ghent University HospitalGhent 9000Belgium Department of Orthopedic Surgery Ghent University HospitalGhent 9000Belgium

Background:Tendinopathy alters the compositional properties of the Achilles tendon by increasing fluid and glycosaminoglycan *** has been speculated that these changes may affect intratendinous pressure,but the extent of this relationship remains ***,we aimed to investigate the impact of elevated fluid and glycosaminoglycan content on Achilles tendon intratendinous pressure and to determine whether hyaluronidase(HYAL) therapy can intervene in this potential ***:Twenty paired fresh-frozen cadaveric Achilles tendons were mounted in a tensile-testing machine and loaded up to 5% *** resting(at 0% strain) and dynamic pressure(at 5% strain) were assessed using the microcapillary infusion ***,intratendinous pressure was measured under native conditions before and after infusion of 2 mL physiological ***,80 mg of glycosaminoglycans were administered bilaterally to the paired *** right tendons were additionally treated with 1500 units of ***,both groups were retested,and the glycosaminoglycan content was ***:It was found that both elevated fluid and glycosaminoglycan content resulted in higher intratendinous resting and dynamic pressures(p <0.001).HYAL treatment induced a 2.3-fold reduction in glycosaminoglycan content(p=0.002) and restored intratendinous ***:The results of this study demonstrated that elevated fluid and glycosaminoglycan content in Achilles tendinopathy contribute to increased intratendinous re sting and dynamic pressures,which can be explained by the associated increased volume and reduced permeability of the tendon matrix,*** degrades glycosaminoglycans sufficiently to lower intratendinous pressures and may,therefore,serve as a promising treatment.

关键词： Achilles tendon Achilles tendinopathy Intratendinous pressure Glycosaminoglycans Tendon fluid

Sustaining forest biodiversity:Exploring the effect of long-term natural disturbance dynamics on contemporary lichen communities in primary forest ecosystems

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Forest Ecosystems 2024年第4期11卷 556-567页

作者： Rhiannon Gloor Marek Svitok Martin Mikolas Jenyk Hofmeister Josef Halda Pavel Janda Francesco Maria Sabatini Lucie Zemanova arne Buechling Daniel Kozak Matej Ferencik Michal Frankovic Martin Dusatko Miroslav Svoboda Department of Forest Ecology Faculty of Forestry and Wood SciencesCzech University of Life Sciences PragueKamycka 129Praha 6–Suchdol16500Czech Republic Faculty of Ecology and Environmental Sciences Technical University in ZvolenT.G.Masaryka 2496001ZvolenSlovakia Institute of Botany Plant Science and Biodiversity CenterSlovak Academy of SciencesDúbravska cesta 984523BratislavaSlovakia PRALES Odtrnovie 56301322RosinaSlovakia Faculty of Science University of Hradec KraloveHradecka 1285Hradec KraloveⅢ50003Czech Republic BIOME–Biogeography and Macroecology Department of BiologicalGeological and Environmental Sciences(BIGEA)Alma Mater Studiorum-University of Bolognavia Irnerio 42BolognaItaly

In this era of biodiversity loss and climate change,quantifying the impacts of natural disturbance on forest communities is imperative to improve biodiversity conservation *** and epixylic lichens are effective forest quality bioindicators,as they are generally long-lived organisms supported by continuity of specific forest structures and their associated microclimatic ***,how lichen communities respond to the effects of fluctuating historical disturbances remains *** a dendrochronological approach,this study investigates how natural disturbance dynamics indirectly influence various lichen community metrics in some of Europe's best-preserved primary mixed-beech *** modelling revealed that natural historical disturbance processes have decades-long effects on forest structural attributes,which had both congruent and divergent impacts on lichen community richness and *** species richness indirectly benefited from both historical and recent higher-severity disturbances via increased standing dead tree basal area and canopy openness respectively-likely through the presence of both pioneer and late-successional species associated with these ***-listed species richness showed a dependence on habitat continuity(old trees),and increased with disturbance-related structures(standing dead trees)whilst simultaneously benefiting from periods without severe disturbance events(old trees and reduced deadwood volume).However,if the disturbance occurred over a century in the past,no substantial effect on forest structure was ***,while disturbance-mediated forest structures can promote overall richness,threatened species appear vulnerable to more severe disturbance events-a concern,as disturbances are predicted to intensify with climate ***,the high number of threatened species found reinforce the critical role of primary forest structural attributes for biodiversity ***

关键词： Mixed-beech forests Species richness Old-growth forests Carpathian mountains Biodiversity conservation Dendroecology Fagus sylvatica

The myelin membrane-associated enzyme 2′,3′-cyclic nucleotide 3′-phosphodiesterase:on a highway to structure and function

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Neuroscience Bulletin 2014年第6期30卷 956-966页

作者： arne Raasakka Petri Kursula Department of Biochemistry and Biocenter Oulu University of OuluOuluFinland Department of Chemistry University of HamburgHamburgGermany

The membrane-anchored myelin enzyme 2′,3′-cyclic nucleotide 3′-phosphodiesterase（CNPase） was discovered in the early 1960 s and has since then troubled scientists with its peculiar catalytic activity and high expression levels in the central nervous system. Despite decades of research, the actual physiological relevance of CNPase has only recently begun to unravel. In addition to a role in myelination, CNPase is also involved in local adenosine production in traumatic brain injury and possibly has a regulatory function in mitochondrial membrane permeabilization. Although research focusing on the CNPase phosphodiesterase activity has been helpful, several open questions concerning the protein function in vivo remain unanswered. This review is focused on past research on CNPase, especially in the fields of structural biology and enzymology, and outlines the current understanding regarding the biochemical and physiological significance of CNPase, providing ideas and directions for future research.

关键词： 2′,3′-cyclic nucleotide 3′-phosphodiesterase calmodulin central nervous system cytoskeleton myelin proteins RNA

Methods of modeling relative growth rate

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Forest Ecosystems 2015年第2期2卷 82-90页

作者： arne Pommerening Anders Muszta Department of Forest Resource Management Faculty of Forest SciencesSwedish University of Agricultural Sciences SLU

Background： Analysing and modelling plant growth is an important interdisciplinary field of plant science. The use of relative growth rates, involving the analysis of plant growth relative to plant size, has more or less independently emerged in different research groups and at different times and has provided powerful tools for assessing the growth performance and growth efficiency of plants and plant populations. In this paper, we explore how these isolated methods can be combined to form a consistent methodology for modelling relative growth rates. Methods： We review and combine existing methods of analysing and modelling relative growth rates and apply a combination of methods to Sitka spruce （Piceo sitchensis （Bong.） Carr.） stem-analysis data from North Wales （UK） and British Douglas fir （Pseudotsugd menziesii （Mirb.） Franco） yield table data. Results： The results indicate that, by combining the approaches of different plant-growth analysis laboratories and using them simultaneously, we can advance and standardise the concept of relative plant growth. Particularly the growth multiplier plays an important role in modelling relative growth rates. Another useful technique has been the recent introduction of size-standardised relative growth rates. Conclusions： Modelling relative growth rates mainly serves two purposes, 1） an improved analysis of growth performance and efficiency and 2） the prediction of future or past growth rates. This makes the concept of relative growth ideally suited to growth reconstruction as required in dendrochronology, climate change and forest decline research and for interdisciplinary research projects beyond the realm of plant science.

关键词： Growth efficiency Growth coefficient/multiplier Chapman-Richards growth model Standardisation Simultaneous estimations

Mitigating self-excited flame pulsating and thermoacoustic oscillations using perforated liners

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Science Bulletin 2019年第13期64卷 941-952页

作者： Dan Zhao Ephraim Gutmark arne Reinecke Department of Mechanical Engineering College of EngineeringUniversity of CanterburyChristchurch 8140New Zealand Department of Aerospace Engineering and Engineering Mechanics University of CincinnatiCincinnatiOH 45221-0070USA School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingapore 639798Singapore

Open-loop control of self-excited flame pulsating oscillations and thermo-acoustic instability is considered in this *** performance of the control strategy is numerically evaluated in a 2 D Rij ke-type combustor with a perfo rated pipe *** is found that approximately 38 dB sound pressure level(SPL)reduction can be achieved by actively tuning the cooling flow through the perforated ***,the vorticity-induced damping performance is contributing to the breaking up of flame-acoustics ***,the shedding of vortices is not uniformly distributed along the perforated *** apply the control strategy in practice and to validate the findings,experimental studies are performed on a customerdesigned Rij ke-type combustor with a perfo rated liner *** mimic practical engines,a cooling flow generated by a centrifugal pump is provided to pass through the perforated *** tuning the cooling flow rate is found to lead to the unstable combustor being successfully *** is red uced by approximately 35 dB at ω1/2π≈245 Hz,and harmonic thermoacoustic modes are completely *** study is conducted by suddenly re moving the perforated pipe *** combustion system is found to be associated with not only classical thermo-acoustic limit cycle oscillations with a dominant mode at 2.45 × 102 Hz,but also beating oscillations at 1.4 × 1 00 *** is revealed that increasing acoustic losses by implementing the perforated pipe is another critical mechanism contributing to attenuating flame pulsating *** present work opens up an applicable means to attenuate both selfexcited high-frequency thermoacoustic and low-frequency flame pulsating oscillations.

关键词： Flame beating Combustion instability Thermo-acoustic instability Thermal-diffusive instability Perforated pipe Acoustic losses

Biliary cholesterol secretion: More than a simple ABC

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World Journal of Gastroenterology 2010年第47期16卷 5936-5945页

作者： arne Dikkers Uwe JF Tietge Department of Pediatrics Center for Liver Digestive and Metabolic DiseasesUniversity Medical Center Groningen University of Groningen

Biliary cholesterol secretion is a process important for 2 major disease complexes, atherosclerotic cardiovascular disease and cholesterol gallstone disease. With respect to cardiovascular disease, biliary cholesterol secretion is regarded as the f inal step for the elimination of cholesterol originating from cholesterol-laden macrophage foam cells in the vessel wall in a pathway named reverse cholesterol transport. On the other hand, cholesterol hypersecretion into the bile is considered the main pathophysiological determinant of cholesterol gallstone formation. This review summarizes current knowledge on the origins of cholesterol secreted into the bile as well as the relevant processes and transporters involved. Next to the established ATP-binding cassette (ABC) transporters mediating the biliary secretion of bile acids (ABCB11), phospholipids (ABCB4) and cholesterol (ABCG5/G8), special attention is given to emerging proteins that modulate or mediate biliary cholesterol secretion. In this regard, the potential impact of the phosphatidylserine flippase ATPase class Ⅰ type 8B member 1, the Niemann Pick C1-like protein 1 that mediatescholesterol absorption and the high density lipoprotein cholesterol uptake receptor, scavenger receptor class B type Ⅰ, is discussed.

关键词： Cholesterol Bile Gallstone Atherosclerosis Reverse cholesterol transport Lipoproteins High density lipoprotein Scavenger receptor class B type Ⅰ

Global woodland structure from local interactions:new nearest-neighbour functions for understanding the ontogenesis of global forest structure

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Forest Ecosystems 2020年第2期7卷 290-300页

作者： arne Pommerening Hongxiang Wang Zhonghua Zhao Faculty of Forest Sciences Department of Forest Ecology and ManagementSwedish University of Agricultural Sciences SLUSkogsmarksgränd 17SE-90183 UmeåSweden College of Forestry Guangxi UniversityNanning 530004China Key Laboratory of Tree Breeding and Cultivation of National Forestry and Grassland Administration Research Institute of ForestryChinese Academy of ForestryBox 1958Beijing 100091China.

Background:A number of hypotheses and theories,such as the Janzen-Connell hypothesis,have been proposed to explain the natural maintenance of biodiversity in tropical and temperate forest ***,to date the details of the processes behind this natural maintenance are still *** two new nearest-neighbour characteristics were proposed and in this paper we demonstrate how they can contribute to a better understanding of the ontogenesis of global forest structure from localised ***:We applied the new species and size segregation functions together with appropriate test procedures to four example woodland data sets from China at Daqingshan,Jiaohe,Jiulongshan and Xiaolongshan forest *** addition we quantified the morphology of the new characteristics and modelled a neighbourhood allometric coefficient linking the two ***:The results revealed quite different species segregation patterns with both conspecific and heterospecific *** found these to be generally matched by equivalent size segregation patterns of attraction of similar and different *** was straightforward to model the size segregation function from the knowledge of the species segregation function by estimating a neighbourhood allometric ***:The new characteristics have helped to quantify the extent and rate of decline of neighbourhood interactions in terms of spatial species and size *** the allometric neighbourhood coefficient the analysis highlighted once more how closely related species and size segregation are,thus supporting the minglingsize *** both a traditional and a restricted random-labelling test has provided a valuable tool for understanding the exact nature of species-mingling and size-inequality relationships.

关键词： Species segregation function Size segregation function Mingling-size hypothesis Neighbourhood allometric coefficient random labelling

Modeling of shear walls using finite shear connector elements based on continuum plasticity

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Frontiers of Structural and Civil Engineering 2017年第2期11卷 143-157页

作者： Ulf arne GIRHAMMAR Per Johan GUSTAFSSON Bo KALLSNER Division of Wood Science and Engineering Lulea University of Technology Skellefiea 93187 Sweden Division of Structural Mechanics Department of Building Sciences Lund University Lund 22100 Sweden Department of Building Technology Linnceus University Vaxjo 35195 Sweden

Light-frame timber buildings are often stabilized against lateral loads by using diaphragm action of roofs, floors and walls. The mechanical behavior of the sheathing-to-framing joints has a significant impact on the structural performance of shear walls. Most sheathing-to-framing joints show nonlinear load-displacement characteristics with plastic behavior. This paper is focused on the finite element modeling of shear walls. The purpose is to present a new shear connector element based on the theory of continuum plasticity. The incremental load-displacement relationship is derived based on the elastic-plastic stiffness tensor including the elastic stiffness tensor, the plastic modulus, a function representing the yield criterion and a hardening rule, and function representing the plastic potential. The plastic properties are determined from experimental results obtained from testing actual connections. Load-displacement curves for shear walls are calculated using the shear connector model and they are compared with experimental and other computational results. Also, the ultimate horizontal load-carrying capacity is compared to results obtained by an analytical plastic design method. Good agreements are found.

关键词： shear walls wall diaphragms finite element modelling plastic shear connector analytical modelling exoerimental comoarison