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Design Improvements and Validation of a Novel Fully 3D Printed Analogue Lumbar Spine Motion Segment

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Journal of Bionic Engineering 2024年第3期21卷 1388-1396页

作者： Siril Teja Dukkipati mark Driscoll Musculoskeletal Biomechanics Research Lab Department of Mechanical EngineeringMcGill University845 Sherbrooke St.W(163)MontréalQCH3A 0C3Canada Orthopaedic Research Lab Montreal General Hospital1650 Cedar Ave(LS1.409)MontréalQCH3G 1A4Canada

Spine biomechanical testing methods in the past few decades have not evolved beyond employing either cadaveric studies or finite element modeling ***,both these approaches may have inherent cost and time *** studies are the present gold standard for spinal implant design and regulatory approval,but they introduce significant variability in measurements across patients,often requiring large sample *** element modeling demands considerable expertise and can be computationally expensive when complex geometry and material nonlinearity are *** analogue spine models could complement these traditional methods as a low-cost and high-fidelity alternative.A fully 3D printable L-S1 analogue spine model with ligaments is developed and validated in this *** stiffness of the model under pure bending loading in flexion-extension,Lateral Bending(LB)and Axial Rotation(AR)is evaluated and compared against historical ex vivo and in silico ***,the effect of interspinous,intertransverse ligaments and the Thoracolumbar Fascia(TLF)on spinal stiffness is evaluated by systematic construction of the *** flexion,model Range of Motion(ROM)was 12.92±0.11°(ex vivo:16.58°,in silico:12.96°)at *** LB,average ROM was 13.67±0.12°at 7.5 Nm(ex vivo:15.21±1.89°,in silico:15.49±0.23°).Similarly,in AR,average ROM was 17.69±2.12°at 7.5Nm(ex vivo:14.12±0.31°,in silico:15.91±0.28°).The addition of interspinous and intertransverse ligaments increased both flexion and LB stiffnesses by approximately 5%.Addition of TLF showed increase in flexion and AR stiffnesses by 29%and 24%,*** novel model can reproduce physiological ROMs with high repeatability and could be a useful open-source tool in spine biomechanics.

关键词： Lumbar spine 3D printing Intervertebral disc Biomechanical testing Spine mechanics

The Wave Front Set Correspondence for Dual Pairs with One Member Compact

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Acta Mathematica Sinica,English Series 2024年第3期40卷 823-869页

作者： mark MCKEE Angela PASQUALE Tomasz PRZEBINDA Hammond Lane ProvidenceUT 84332USA Universite de Lorraine CNRSIECLF-57000 MetzFrance Department of Mathematics University of OklahomaNormanOK 73019USA

Let W be a real symplectic space and(G,G')an irreducible dual pair in Sp(W),in the sense of Howe,with G *** G be the preimage of G in the metaplectic group Sp(W).Given an irreducible unitary representation II of G that occurs in the restriction of the Weil representation to G,let On denote its *** prove that,for a suitable embedding T of Sp(W)in the space of tempered distributions on W,the distribution T(On)admits an asymptotic limit,and the limit is a nilpotent orbital *** an application,we compute the wave front set of II',the representation of G dual to II,by elementary means.

关键词： Reductive dual pairs Howe duality Weil representation wave front set orbital integrals

Is Deep Time Geology Scientific?

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Journal of Earth Science 2024年第2期35卷 700-703页

作者： T.mark Harrison Department of Earth Planetary and Space SciencesUniversity of CaliforniaLos Angeles90095USA

We all know what car mechanics *** maintain and repair our automobiles according to established engineering *** all know what physicians *** maintain and repair our bodies according to established medical *** what is it that I do as a scientist?Indeed,am I a scientist?The answer to these questions depends on what we meant by“science”.

关键词： maintain Deep repair

Normal Crossings Singularities for Symplectic Topology:Structures

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Acta Mathematica Sinica,English Series 2024年第1期40卷 107-160页

作者： Mohammad FARAJZADEH-TEHRANI mark MCLEAN Aleksey ZINGER The University of Iowa MacLean HallIowa CityIA 52241 Department of Mathematics Stony Brook UniversityStony BrookNY 11794

Our previous papers introduce topological notions of normal crossings symplectic divisor and variety,show that they are equivalent,in a suitable sense,to the corresponding geometric notions,and establish a topological smoothability criterion for normal crossings symplectic *** present paper constructs a blowup,a complex line bundle,and a logarithmic tangent bundle naturally associated with a normal crossings symplectic divisor and determines the Chern class of the last *** structures have applications in constructions and analysis of various moduli *** a corollary of the Chern class formula for the logarithmic tangent bundle,we refine Aluffi’s formula for the Chern class of the tangent bundle of the blowup at a complete intersection to account for the torsion and extend it to the blowup at the deepest stratum of an arbitrary normal crossings divisor.

关键词： Normal crossings divisor Chern class Logarithmic tangent bundle

Analysis of the inflection points of height-diameter models

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Forest Ecosystems 2024年第4期11卷 414-422页

作者： Tzeng Yih Lam mark J.Ducey Department of Forest Resources Management Faculty of ForestryThe University of British Columbia2045-2424 Main MallVancouverBCV6T 1Z4 Canada Department of Natural Resources and the Environment University of New Hampshire114 James HallDurhamNH 03824USA

The inflection point is an important feature of sigmoidal height-diameter(H-D)*** is often cited as one of the properties favoring sigmoidal model ***,there are very few studies analyzing the inflection points of H-D *** goals of this study were to theoretically and empirically examine the behaviors of inflection points of six common H-D models with a regional *** six models were the Wykoff(WYK),Schumacher(SCH),Curtis(CUR),HossfeldⅣ(HOS),von Bertalanffy-Richards(VBR),and Gompertz(GPZ)*** models were first fitted in their base forms with tree species as random effects and were then expanded to include functional traits and spatial *** distributions of the estimated inflection points were similar between the two-parameter models WYK,SCH,and CUR,but were different between the threeparameter models HOS,VBR,and *** produced some of the largest inflection *** and VBR produced concave H-D curves without inflection points for 12.7%and 39.7%of the tree *** species or decreasing shade tolerance resulted in larger inflection *** trends in the estimated inflection points of HOS and VBR were entirely opposite across the ***,HOS could produce concave H-D curves for portions of the *** on the studied behaviors,the choice between two-parameter models may not *** recommend comparing seve ral three-parameter model forms for consistency in estimated inflection points before deciding on *** sigmoidal models to have inflection points does not necessarily mean that they will produce fitted curves with *** study highlights the need to integrate analysis of inflection points into modeling H-D relationships.

关键词： Concavity Forest inventory and analysis Generalized height-diameter models Growth functions Height-diameter functions Mixed-effects modeling Points of inflection Species-specific models

Electroactivity of the magnetotactic bacteria Magnetospirillum magneticum AMB-1 and Magnetospirillum gryphiswaldense MSR-1

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Frontiers of Environmental Science & Engineering 2024年第4期18卷 103-110页

作者： Mathias Fessler Qingxian Su Marlene mark Jensen Yifeng Zhang Department of Environmental and Resource Engineering Technical University of DenmarkCopenhagenDK-2800Denmark

Magnetotactic bacteria reside in sediments and stratified water *** are named after their ability to synthesize internal magnetic particles that allow them to align and swim along the Earth’s magnetic field ***,we show that two magnetotactic species,Magnetospirillum magneticum strain AMB-1 and Magnetospirillum gryphiswaldense strain MSR-1,are *** *** and *** were able to generate current in microbial fuel cells with maximum power densities of 27 and 11μW/m^(2),*** the presence of the electron shuttle resazurin both species were able to reduce the crystalline iron oxide hematite(Fe_(2)O_(3)).In addition,*** could reduce poorly crystalline iron oxide(FeOOH).Our study adds *** and *** to the growing list of known electroactive bacteria,and implies that electroactivity might be common for bacteria within the Magnetospirillum genus.

关键词： Magnetotactic bacteria Magnetospirillum magneticum Magnetospirillum gryphiswaldense Extracellular electron transfer Microbial fuel cells

Monomeric C-reactive protein:a link between chronic inflammation and neurodegeneration?

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Neural Regeneration Research 2024年第8期19卷 1643-1644页

作者： Nicoleta Arnaut Ylenia Pastorello mark Slevin George Emil Palade University of Medicine PharmacyScience and TechnologyTârgu MuresRomania Department of Anatomy and Embryology George Emil Palade University of MedicinePharmacyScience and TechnologyTârgu MuresRomania Center for Advanced Medical and Pharmaceutical Research(CCAMF) George Emil Palade University of MedicinePharmacyScience and TechnologyTârgu MuresRomania

Pre-diabetic insulin resistance is associated with sub-clinical inflammation and concomitant increase in systemic C-reactive protein(CRP)*** 2 diabetes mellitus(T2DM)patients register even higher chronic levels of inflammation,with excess circulating CRP originating from both typical hepatic synthesis,and also visceral white adipose tissue.

关键词： inflammation reactive clinical

Climate-change habitat shifts for the vulnerable endemic oak species(Quercus arkansana Sarg.)

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Journal of Forestry Research 2024年第1期35卷 117-127页

作者： Suresh Chandra Subedi Seth Drake Binaya Adhikari mark V.Coggeshall Department of Biological Sciences Arkansas Tech UniversityRussellvilleARUSA Department of Biology University of KentuckyLexingtonKYUSA School of Natural Resources University of Missouri203 ABNR BuildingColumbiaMO 65211USA

Quercus arkansana(Arkansas oak)is at risk of becoming endangered,as the total known population size is represented by a few isolated *** potential impact of climate change on this species in the near future is high,yet knowledge of its predicted effects is *** study utilized the biomod2 R package to develop habi-tat suitability ensemble models based on bioclimatic and topographic environmental variables and the known loca-tions of current distribution of *** predicted suitable habitats across three climate change scenarios(SSP1-2.6,SSP2-4.5,and SSP5-8.5)for 2050,2070,and *** findings reveal that the current suitable habitat for *** is approximately 127,881 km^(2) across seven states(Texas,Arkansas,Alabama,Louisiana,Mississippi,Georgia,and Florida);approximately 9.5%is encompassed within state and federally managed protected *** models predict that all current suitable habitats will disap-pear by 2050 due to climate change,resulting in a northward shift into new regions such as Tennessee and *** large extent of suitable habitat outside protected areas sug-gests that a species-specific action plan incorporating pro-tected areas and other areas may be crucial for its ***,protection of *** habitat against climate change may require locally and regionally focused conservation policies,adaptive management strategies,and educational outreach among local people.

关键词： Biomod2 Climate change Conservation Habitat loss Habitat shift Species distribution modeling Oak species