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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

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

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

The efficacy of vitamin E in preventing arthrofibrosis after joint replacement

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Animal Models and Experimental Medicine 2024年第2期7卷 145-155页

作者： Yingfang Fan Jean Yuh Sashank Lekkala Mehmet d.Asik Andrew Thomson Madeline McCanne mark A.Randolph Antonia F.Chen Ebru Oral Harris Orthopaedic Laboratory Department of Orthopaedic SurgeryMassachusetts General HospitalBostonMassachusettsUSA department of Orthopaedic Surgery Harvard Medical SchoolBostonMassachusettsUSA department of Surgery Harvard Medical SchoolBostonMassachusettsUSA department of Orthopaedic Surgery Brigham and Women's HospitalBostonMassachusettsUSA

Background:Arthrofibrosis is a joint disorder characterized by excessive scar formation in the joint *** E is an antioxidant with potential anti-fibroblastic *** aim of this study was to establish an arthrofibrosis rat model after joint replacement and assess the effects of vitamin E supplementation on joint ***:We simulated knee replacement in 16 male Sprague–dawley *** immobilized the surgical leg with a suture in full *** control groups were killed at 2 and 12 weeks(n=5 per group),and the test group was supplemented daily with vitamin E(0.2 mg/mL)in their drinking water for 12 weeks(n=6).We performed histological staining to investigate the presence and severity of *** staining andα2-macroglobulin(α2M)enzyme-linked immunosorbent assay(ELISA)were used to assess local and systemic *** weight bearing(total internal reflection)and range of motion(ROM)were collected for functional ***:The ROM and weight-bearing symmetry decreased after the procedure and recovered slowly with still significant deficit at the end of the study for both *** analysis confirmed fibrosis in both lateral and posterior periarticular *** E supplementation showed a moderate anti-inflammatory effect on the local and systemic *** vitamin E group exhibited significant improvement in ROM and weight-bearing symmetry at day 84 compared to the control ***:This model is viable for simulating arthrofibrosis after joint *** E may benefit postsurgical arthrofibrosis,and further studies are needed for dosing requirements.

关键词： arthrofibrosis range of motion total knee arthroplasty vitamin E

Biopolymer stabilization of clayey soil

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2801-2812页

作者： Mahdieh Azimi Amin Soltani Mehdi Mirzababaei mark B.Jaksa Nanjappa Ashwath College of Engineering and Aviation School of Engineering and TechnologyCQUniversityMelbourneVIC 3000Australia Institute of Innovation Science and Sustainabilityand Future Regions Research CenterFederation UniversityChurchillVIC 3842Australia department of Infrastructure Engineering Faculty of Engineering and Information TechnologyThe University of MelbourneParkvilleVIC 3010Australia School of Architecture and Civil Engineering The University of AdelaideAdelaideSA 5005Australia School of Health Medical and Applied SciencesCQUniversityRockhamptonQLD 4701Australia

This study investigates the efficacy of sodium alginate(SA),xanthan gum(XG),guar gum(GG)and chitosan(CS)d each applied at five different solid biopolymer-to-water mass ratios(or dosages)and cured for 7 d and 28 d d on the unconfined compressive strength(UCS)performance of a high plasticity clayey ***,on identifying the optimum biopolymer-treatment scenarios,their performance was compared against conventional stabilization using hydrated *** a given curing time,the UCS for all biopolymers followed a riseefall trend with increasing biopolymer dosage,peaking at an optimum dosage and then subsequently decreasing,such that all biopolymer-stabilized samples mobilized higher UCS values compared to the unamended *** optimum dosage was found to be 1.5%for SA,XG and CS,while a notably lower dosage of 0.5%was deemed optimum for ***,for a given biopolymer type and dosage,increasing the curing time from 7 d to 28 d further enhanced the UCS,with the achieved improvements being generally more pronounced for XG-and CS-treated *** of the investigated biopolymers was able to produce UCS improvements equivalent to those obtained by the 28-d soilelime samples;however,the optimum XG,GG and CS dosages,particularly after 28 d of curing,were easily able to replicate 7-d lime stabilization outcomes achieved with as high as twice the soil’s lime ***,the fundamental principles of clay chemistry,in conjunction with the soil mechanics framework,were employed to identify and discuss the clayebiopolymer stabilization mechanisms.

关键词： Soil stabilization High plasticity clay Biopolymer dosage Hydrated lime Curing time Unconfined compressive strength(UCS)

Prehospital transdermal glyceryl trinitrate for ultra- acute ischaemic stroke: data from the RIGHT- 2 randomised sham- controlled ambulance trial

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Stroke & Vascular Neurology 2024年第1期9卷 38-49,I0035-I0046页

作者： Jason Philip Appleton Lisa J Woodhouse Craig S Anderson Sandeep Ankolekar Lesley Cala mark dixon Timothy J England Kailash Krishnan grant Mair Keith W Muir John Potter Christopher I Price Marc Randall Thompson G Robinson Christine Roffe Else C Sandset Jeffrey L Saver Angela Shone Aloysius Niroshan Siriwardena Joanna M Wardlaw Nikola Sprigg Philip M Bath Stroke University Hospitals Birmingham NHS Foundation TrustBirminghamUK Institute of Applied HealthResearch University of Birmingham College of Medical and Dental SciencesBirminghamUK Stroke Trials Unit Mental Health and Clinical NeurosciencesUniversity of NottinghamNottinghamUK Faculty of Medicine The George Institute for Global HealthSydneyNew South WalesAustralia The George Institute China at Peking University Health Science Center BeijingChina Neurology Royal Prince Alfred HospitalSydney Health PartnersSydneyNew South WalesAustralia department of Neurology King's College Hospital NHS Foundation TrustLondonUK Faculty of Health and Medical Sciences University of Western AustraliaCrawleyWestern AustraliaAustralia East Midlands Ambulance Service NHS Trust NottinghamUK Stroke Queen's Medical CentreNottingham University Hospitals NHS TrustNottinghamUK Centre for Clinical Brain Sciences Dementia Research InstituteUniveristy of EdinburghEdinburghUK Institute of Neurology and Psychology University of GlasgowGlasgowUK Bob Champion Research and Education Building University of East AngliaNorwichUK Institute of Neuroscience Newcastle UniversityNewcastle upon TyneUK department of Neurology Leeds Teaching Hospitals NHS TrustLeedsUK department of Cardiovascular Sciences and NIHR Leicester Biomedical Research Centre University of LeicesterLeicesterUK Stroke Research in Stoke Institute for Science and Technology in MedicineKeele UniversityStoke-on TrentUK department of Neurology Oslo University HospitalOsloNorway Research and development Norwegian Air Ambulance FoundationOsloNorway department of Neurology and Comprehensive Stroke Center David Geffen School of MedicineUCLALos AngelesCaliforniaUSA Research and Graduate Services University of NottinghamNottinghamUK Community and Health Research Unit University of LincolnLincolnUK

Background The effect of transdermal glyceryl trinitrate(GTN,a nitrovasodilator)on clinical outcome when administered before hospital admission in suspected stroke patients is ***,we assess the safety and efficacy of GTN in the prespecified subgroup of patients who had an ischaemic stroke within the Rapid Intervention with Glyceryl trinitrate in Hypertensive stroke Trial-2(RIGHT-2).Methods RIGHT-2 was an ambulance-based multicentre sham-controlled blinded-endpoint study with patients randomised within 4hours of *** primary outcome was a shift in scores on the modified Rankin scale(mRS)at day *** outcomes included death;a global analysis(Wei-Lachin test)containing Barthel Index,EuroQol-5d,mRS,telephone interview for cognitive status-modified and Zung depression scale;and neuroimaging-determined‘brain frailty’*** were reported as n(%),mean(Sd),median[IQR],adjusted common OR(acOR),mean difference or Mann-Whitney difference(MWd)with 95%*** 597 of 1149(52%)patients had a final diagnosis of ischaemic stroke;age 75(12)years,premorbid mRS>2107(18%),Glasgow Coma Scale 14(2)and time from onset to randomisation 67[45,108]***‘brain frailty’was common:median score 2[2,3](range 0–3).At day 90,GTN did not influence the primary outcome(acOR for increased disability 1.15,95%CI 0.85 to 1.54),death or global analysis(MWd 0.00,95%CI-0.10 to 0.09).In subgroup analyses,there were non-significant interactions suggesting GTN may be associated with more death and dependency in participants randomised within 1hour of symptom onset and in those with more severe *** In patients who had an ischaemic stroke,ultra-acute administration of transdermal GTN in the ambulance did not improve clinical outcomes in a population with more clinical and radiological frailty than seen in previous in-hospital *** IS ALREAdY KNOWN ON THIS TOPIC⇒Transdermal glyceryl trinitrate(GTN)was associat-ed with less death and dependency in those w

关键词： Glasgow nitrate random

A three-dimensional feature extraction-based method for coal cleat characterization using X-ray μCT and its application to a Bowen Basin coal specimen

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 153-166页

作者： Yulai Zhang Matthew Tsang mark Knackstedt Michael Turner Shane Latham Euan Macaulay Rhys Pitchers ARC Training Centre for M3d Innovation Research School of PhysicsAustralian National UniversityCanberraACT2601Australia department of Materials Physics Research School of PhysicsAustralian National UniversityCanberraACT2601Australia Anglo American Steelmaking Coal BrisbaneQLD4000Australia SCT Operations Pty Ltd. WollongongNSW2500Australia

Cleats are the dominant micro-fracture network controlling the macro-mechanical behavior of *** understanding of the spatial characteristics of cleat networks is therefore important to the coal mining *** fracture networks(dFNs)are increasingly used in engineering analyses to spatially model fractures at various *** reliability of coal dFNs largely depends on the confidence in the input cleat *** of these parameters can be made from image-based three-dimensional(3d)characterization of coal cleats using X-ray micro-computed tomography(m CT).One key step in this process,after cleat extraction,is the separation of individual cleats,without which the cleats are a connected network and statistics for different cleat sets cannot be *** this paper,a feature extraction-based image processing method is introduced to identify and separate distinct cleat groups from 3d X-ray m CT ***(filters)representing explicit cleat features of coal are built and cleat separation is successfully achieved by convolutional operations on 3d coal *** new method is applied to a coal specimen with 80 mm in diameter and 100 mm in length acquired from an Anglo American Steelmaking Coal mine in the Bowen Basin,Queensland,*** is demonstrated that the new method produces reliable cleat separation capable of defining individual cleats and preserving 3d topology after ***-parallel fractures are also identified and separated,which has his-torically been challenging to delineate and rarely reported.A variety of cleat/fracture statistics is measured which not only can quantitatively characterize the cleat/fracture system but also can be used for dFN ***,variability and heterogeneity with respect to the core axis are *** heterogeneity is observed and suggests that the representative elementary volume(REV)of the cleat groups for engineering purposes may be a complex problem requ

关键词： Cleat separation Cleat statistics Feature extraction discrete fracture network(dFN)modeling

What diameter?What height?Influence of measures of average tree size on area-based allometric volume relationships

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Forest Ecosystems 2024年第1期11卷 100-109页

作者： Yilin Wang John A.Kershaw mark J.ducey Yuan Sun James B.McCarter Integrated Forest Mensuration and Systems Analysis Laboratory Faculty of Forestry and Environmental ManagementUniversity of New BrunswickFrederictonNBCanada department of Natural Resources and the Environment University of New HampshireDurhamNHUSA College of Forestry Nanjing Forestry UniversityNanjing210037China Scientific Programmer RayonierYuleeFLUSA

Volume is an important attribute used in many forest management *** from 83 fixed-area plots located in central New Brunswick,Canada,are used to examine how different measures of stand-level diameter and height influence volume prediction using a stand-level variant of Honer's(1967)volume *** density was included in the models(Volume=f(diameter,Height,density))choice of diameter measure was more important than choice of height *** density was not included(Volume=f(diameter,Height)),the opposite was *** models with density included,moment-based estimators of stand diameter and height performed better than all other *** models without density,largest tree estimators of stand diameter and height performed better than other *** overall best equation used quadratic mean diameter,Lorey's height,and density(root mean square error=5.26 m^3·ha^(-1);1.9%relative error).The best equation without density used mean diameter of the largest trees needed to calculate a stand density index of 400 and the mean height of the tallest 400 trees per ha(root mean square error=32.08 m^(3)·ha^(-1);11.8%relative error).The results of this study have some important implications for height subsampling and LidAR-derived forest inventory analyses.

关键词： Allometric relationships Stand structure Volume estimation Stand-level attributes