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Applications of finite element simulation in orthopedic and trauma surgery

World Journal of Orthopedics 2012年第4期3卷 25-41页

作者： antonio Herrera Elena Ibarz José Cego?ino antonio lobo-escolar Sergio Puértolas Enrique López Jesús Mateo Luis Gracia Department of Orthopaedic and Trauma Surgery Miguel Servet University HospitalMedicine SchoolUniversity of Zaragoza Department of Mechanical Engineering University of Zaragoza

Research in different areas of orthopedic and trauma surgery requires a methodology that allows both a more economic approach and the ability to reproduce different situations in an easy way. Simulation models have been introduced recently in bioengineering and could become an essential tool in the study of any physiological unity, regardless of its complexity. The main problem in modeling with finite elements simulation is to achieve an accurate reproduction of the anatomy and a perfect correlation of the different structures, in any region of the human body. Authors have developed a mixed technique, joining the use of a three-dimensional laser scanner Roland Picza captured together with computed tomography(CT) and 3D CT images, to achieve a perfect reproduction of the anatomy. Finite element(FE) simulation lets us know the biomechanical changes that take place after hipprostheses or osteosynthesis implantation and biological responses of bone to biomechanical changes. The simulation models are able to predict changes in bone stress distribution around the implant, so allowing preventing future pathologies. The development of a FE model of lumbar spine is another interesting application of the simulation. The model allows research on the lumbar spine, not only in physiological conditions but also simulating different load conditions, to assess the impact on biomechanics. Different degrees of disc degeneration can also be simulated to determine the impact on adjacent anatomical elements. Finally, FE models may be useful to test different fixation systems, i.e., pedicular screws, interbody devices or rigid fixations compared with the dynamic ones. We have also developed models of lumbar spine and hip joint to predict the occurrence of osteoporotic fractures, based on densitometric determinations and specific biomechanical models, including approaches from damage and fracture mechanics. FE simulations also allow us to predict the behavior of orthopedic splints applied to the correction of deformities, providing the

关键词： Finite element simulation Hip prosthesis Lumbar spine Lumbar fixations Osteoporotic fractures Splints

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Instability of the lumbar spine due to disc degeneration. A finite element simulation

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Advances in Bioscience and Biotechnology 2013年第4期4卷 548-556页

作者： Elena Ibarz Yolanda Más Jesús Mateo antonio lobo-escolar antonio Herrera Luis Gracia Aragón Health Sciences Institute Zaragoza Spain Aragón Institute for Engineering Research (I3A) Zaragoza Spain Department of Mechanical Engineering University of Zaragoza Zaragoza Spain Department of Orthopaedic Surgery and Traumatology Miguel Servet University Hospital Zaragoza Spain Department of Surgery University of Zaragoza Zaragoza Spain

Low back pain, which most common cause is degenerative disc disease, currently represents a serious problem due to its socio-economic repercussions. Different factors are involved in the degenerative process, being the most common: the loads on the spine, repeated flexion movements and individual genetic characteristics. Nowadays, there is no agreement on whether instability is the main cause of low back pain, or only one reason among many, and on whether increased spinal mobility, associated with instability, occurs either locally or at the lumbar spine as a whole. In this work, the simulation of disc degeneration is based on a finite element model of lumbar spine. A parametric study based on mechanical properties was established, for each lumbar spine movement, by evaluating the disc degeneration in 10% steps, from healthy disc to maximum degeneration. The results show as general trend a progressive mobility increase as the disc degeneration level raises. As main conclusion, disc degeneration causes increased mobility at all vertebral levels, with moderate values for incipient degeneration and much higher values for advanced degeneration, affecting more severely to the levels closest to degenerated disk. The great mobility increase detected at L5 could explain the instability detected as a clinical symptom.

关键词： Lumbar Spine Finite Elements Biomechanics Kinematics Mobility Disc Degeneration

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Probability of Osteoporotic Vertebral Fractures Assessment Based on DXA Measurements and Finite Element Simulation

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Advances in Bioscience and Biotechnology 2014年第6期5卷 527-545页

作者： Enrique López Elena Ibarz antonio Herrera Jesús Mateo antonio lobo-escolar Sergio Puértolas Luis Gracia Aragón Health Sciences Institute Zaragoza Spain Department of Design and Manufacturing Engineering University of Zaragoza Zaragoza Spain Department of Mechanical Engineering University of Zaragoza Zaragoza Spain Department of Orthopaedic Surgery and Traumatology Miguel Servet University Hospital Zaragoza Spain Department of Surgery University of Zaragoza Zaragoza Spain

Osteoporotic vertebral fractures represent major cause of disability, loss of quality of life and even mortality among the elderly population. Decisions on drug therapy are based on the assessment of risk factors for fracture, from bone mineral density measurements. The combination of biomechanical models with clinical studies could better estimate bone strength and support the specialists in their decision. A model to assess the probability of fracture, based on the Damage and Fracture Mechanics has been developed, evaluating the mechanical magnitudes involved in the fracture process from clinical bone mineral density measurements. The model is intended for simulating the degenerative process in the skeleton, with the consequent lost of bone mass and hence the decrease of its mechanical resistance which enables the fracture due to different traumatisms. Clinical studies were chosen, both in non-treatment conditions and receiving drug therapy, and fitted to specific patients according their actual bone mineral density measures. The predictive model is applied in a finite element simulation of the lumbar spine. The fracture zone would be determined according loading scenario (fall, impact, accidental loads, etc.), using the mechanical properties of bone obtained from the evolutionary model corresponding to the considered time. Bone mineral density evolution in untreated patients and in those under different treatments was analyzed. Evolutionary curves of fracture probability were obtained from the evolution of mechanical damage. The evolutionary curve of the untreated group of patients presented a marked increase of the fracture probability, while the curves of patients under drug treatment showed variable decreased risks, depending on the therapy type. The finite element model allowed obtaining detailed maps of damage and fracture probability, identifying high-risk local zones at vertebral body, which are the usual localization of osteoporotic vertebral fractures. The developed model is suitable for being used in

关键词： Osteoporosis Osteoporotic Vertebral Fracture Predictive Model Finite Elements Fracture Risk Fracture Probability

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Male osteoporosis: A review

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World Journal of Orthopedics 2012年第12期3卷 223-234页

作者： antonio Herrera antonio lobo-escolar Jesús Mateo Jorge Gil Elena Ibarz Luis Gracia Department of Orthopedic and Trauma Surgery Miguel Servet University Hospital 50009 Zaragoza Spain Department of Mechanical Engineering University of Zaragoza 50009 Zaragoza Spain

Osteoporosis in men is a heterogeneous disease that has received little attention.However,one third of worldwide hip fractures occur in the male population.This problem is more prevalent in people over70 years of age.The etiology can be idiopathic or secondary to hypogonadism,vitamin D deficiency and inadequate calcium intake,hormonal treatments for prostate cancer,use of toxic and every disease or drug use that alters bone metabolism.Risk factors such as a previous history of fragility fracture should be assessed for the diagnosis.However,risk factors in men are very heterogeneous.There are significant differences in the pharmacological treatment of osteoporosis between men and women fundamentally due to the level of evidence in published trials supporting each treatment.New treatments will offer new therapeutic prospects.The goal of this work is a revision of the present status knowledge about male osteoporosis.

关键词： Male osteoporosis Skeleton involution Etiology Fracture risk Osteoporosis Non-pharmacological treatments Pharmacological treatments

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Integrating Levels of Hierarchical Organization in Porous Organic Molecular Materials

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Nano-Micro Letters 2024年第5期16卷 134-153页

作者： Jesus Ferrando‑Soria antonio Fernandez Instituto de Ciencia Molecular(ICMol) Universidad de Valencia46980 ValenciaSpain School of Science Loughborough UniversityLoughborough LE113TUUK

Porous organic molecular materials(POMMs)are an emergent class of molecular-based materials characterized by the formation of extended porous frameworks,mainly held by non-covalent interactions.POMMs represent a variety of chemical families,such as hydrogen-bonded organic frameworks,porous organic salts,porous organic cages,C-H···πmicroporous crystals,supramolecular organic frameworks,π-organic frameworks,halogen-bonded organic framework,and intrinsically porous molecular materials.In some porous materials such as zeolites and metal organic frameworks,the integration of multiscale has been adopted to build materials with multifunctionality and optimized properties.Therefore,considering the significant role of hierarchy in porous materials and the growing importance of POMMs in the realm of synthetic porous materials,we consider it appropriate to dedicate for the first time a critical review covering both topics.Herein,we will provide a summary of literature examples showcasing hierarchical POMMs,with a focus on their main synthetic approaches,applications,and the advantages brought forth by introducing hierarchy.

关键词： Porous organic molecular materials Hierarchy Hydrogen-bonded organic frameworks Porous cages Fullerene

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Cost-effective synthesis of giant molecule acceptors(GMAs)for stable polymer solar cells

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Science China Chemistry 2024年第4期67卷 1041-1043页

作者： antonio Facchetti Department of Chemistry and the Materials Research Center Northwestern University2145 Sheridan Road60208 EvanstonIllinoisUSA School of Materials Science and Engineering Georgia Institute of Technology771 Ferst Drive30332 AtlantaGeorgiaUSA

Polymer solar cells(PSCs)have emerged as a disruptive energy technology due to simple device architecture,earthabundant elemental composition,lightweight nature,and inherent mechanical flexibility[1,2].Via a strategic acceptordonor-acceptor(A-D-A)design of small-molecule acceptors(SMAs),device power conversion efficiency(PCE)has now increased>19%.

关键词： acceptor synthesis donor

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SARS-CoV-2 immunity

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Cellular & Molecular Immunology 2024年第2期21卷 101-102页

作者： antonio Bertoleti Program in Emerging Infectious Diseases Duke-NUS Medical SchoolSingaporeSingapore

Four years have swiftly passed since the identification of a novel coronavirus from patients with pneumonia that signs the start of the COVID-19 pandemic[1].The world's social and economic landscape has largely reverted to its prepandemic state,and different issues unrelated to the pandemic are currently impacting various regions globally.The scientific community,which quickly modified its research focus during the initial years of the pandemic to generate a wealth of scientific data that helped in understanding and controlling SARS-CoV-2 infection,is also facing a new phase in the study of virus-host interactions.

关键词： immunity globally landscape

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Litter production and leaf nutrient concentration and remobilization in response to climate seasonality in the central Amazon

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Journal of Forestry Research 2024年第3期35卷 131-141页

作者： Ricardo antonio Marenco Saul Alfredo Antezana-Vera Daniela Pereira Dias Luiz antonio Candido Instituto Nacional de Pesquisas da Amazonia Coordenagao de Uso da Terra e Mudanca ClimaticaAv.Andre Araujo 2936ManausAM69067-375Brazil Programa de pos-Graduagao em Agricultura no Tropico Umido Instituto Nacional de Pesquisas da Amazonia-INPAManausAMBrazil Unidade Academica de Ciencias Agrarias Universidade Federal de JataiBR 364km 195JataiGO 75801-615Brazil

Litterfall is the largest source of nutrients to for-est soils of tropical rainforests.However,variability in lit-terfall production,nutrient remobilization,and changes in leaf nutrient concentration with climate seasonality remain largely unknown for the central Amazon.This study meas-ured litterfall production,leaf nutrient remobilization,and leaf area index on a forest plateau in the central Amazon.Litterfall was measured at monthly intervals during 2014,while nitrogen,phosphorus,potassium,calcium and mag-nesium concentrations of leaf litter and canopy leaves were measured in the dry and rainy seasons,and remobilization rates determined.Leaf area index was also recorded in the dry and rainy seasons.Monthly litterfall varied from 33.2(in the rainy season)to 87.6 g m^(-2) in the dry season,while leaf area index increased slightly in the rainy season.Climatic seasonality had no effect on concentrations of nitrogen,calcium,and magnesium,whereas phosphorous and potassium responded to rainfall seasonality oppositely.While phosphorous increased,potassium decreased during the dry season.Over seasons,nitrogen,potassium,and phosphorous decreased in leaf litter;calcium increased in leaf litter,while magnesium remained unaffected with leaf aging.Regardless,the five nutrients had similar remobilization rates over the year.The absence of climate seasonality on nutrient remobilization suggests that the current length of the dry season does not alter nutrient remobilization rates but this may change as dry periods become more prolonged in the future due to climate change.

关键词： Throughfall Nutrient cycling Climatic seasonality Leaf mass per area

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Larval development and voracity of Eupeodes americanus (Diptera: Syrphidae): comparison of the focal prey Aphis gossypi (Hemiptera: Aphididae) and the banker prey Rhopalosiphum padi (Hemiptera: Aphididae)

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Insect Science 2024年第2期31卷 575-586页

作者： Arlette Fauteux antonio Onofre Soares Eric Lucas Laboratoire de lutte biologique Departement des sciences biologiquesUniversite du Quebec a Montreal(UQAM)MontrealQuebecCanada Faculty of Science and Technology Center for Ecology Evolution and Environmental ChangesAzorean Biodiversity Group(cE3c-ABG)&CHANGE-Global Change and Sustainability InstitutePonta DelgadaPortugal

Unlike European species,the potential of Nearctic syrphids as biological control agents is still poorly studied.However,the American hoverfly,Eupeodes americanus(Wiedemann),has recently demonstrated promising traits as a biocontrol agent,notably against the foxglove aphid,Aulacorthum solani Kaltenbach,on pepper.The present study aims to extend our knowledge of the American hoverfly by evaluating its potential as a biocontrol agent in a banker plant system against the melon aphid,Aphis gossypi Glover,in a greenhouse cucumber crop.The preimaginal development and voracity of E.americanus were compared when preying upon the focal prey/pest(A.gossypi)or the banker prey(bird cherry-oat aphid,Rhopalosiphum padi L.)by daily observations of larvae from egg to adult.Preimaginal development time,survival rate,and occurrence of deformation were similar on both prey species.The weight of third instar and pupae,however,was higher for larvae that fed on the banker prey.The ad libitum voracity of the syrphid larvae was generally very high and did not significantly differ between prey species,except for the third-instar larvae which consumed more focal prey.Results suggest that a banker plant system involving the bird cherry-oat aphid may be a promising tactic for utilizing E.americanus for melon aphid biocontrol.

关键词： american hoverfly banker plant system biological control bird cherry-oat aphid greenhouse cucumber melon aphid

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Opto-fluidically multiplexed assembly and micro-robotics

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Light(Science & Applications) 2024年第3期13卷 544-554页

作者： Elena Erben Weida Liao antonio Minopoli Nicola Maghelli Eric Lauga Moritz Kreysing Max Planck Institute of Molecular Cell Biology and Genetics Dresden 01307Germany Center for Systems Biology Dresden 01307Germany Institute of Biological and Chemical Systems–Biological Information Processing.Karlsruhe Institute of Technology(KIT) Eggenstein-Leopoldshafen 76344Germany Department of Applied Mathematics and Theoretical Physics University of CambridgeCambridge CB30WAUK

Techniques for high-definition micromanipulations,such as optical tweezers,hold substantial interest across a wide range of disciplines.However,their applicability remains constrained by material properties and laser exposure.And while microfluidic manipulations have been suggested as an alternative,their inherent capabilities are limited and further hindered by practical challenges of implementation and control.Here we show that the iterative application of laser-induced,localized flow fields can be used for the relative positioning of multiple micro-particles,irrespectively of their material properties.Compared to the standing theoretical proposal,our method keeps particles mobile,and we show that their precision manipulation is non-linearly accelerated via the multiplexing of temperature stimuli below the heat diffusion limit.The resulting flow fields are topologically rich and mathematically predictable.They represent unprecedented microfluidic control capabilities that are illustrated by the actuation of humanoid micro-robots with up to 30 degrees of freedom,whose motions are sufficiently well-defined to reliably communicate personal characteristics such as gender,happiness and nervousness.Our results constitute high-definition micro-fluidic manipulations with transformative potential for assembly,micro-manufacturing,the life sciences,robotics and optohydraulically actuated micro-factories.

关键词： manipulation fluid assembly

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