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THREE-DIMENsIONAL NUMERICAL LOCALIZATION OF IMPERFECTIONs BAsED ON A LIMIT MODEL IN ELECTRIC FIELD AND A LIMIT PERTURBATION MODEL

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Journal of Computational Mathematics 2009年第4期27卷 495-524页

作者： s.M.mefire LAMFA CNRS UMR 6140Université de Picardie33 r.Saint-Leu80039 Amiens Cedex 1France

From a limit model in electric field obtained by letting the frequency vanish in the time-harmonic Maxwell equations, we consider a limit perturbation model in the tangential boundary trace of the curl of the electric field for localizing numerically certain small electromagnetic inhomogeneities, in a three-dimensional bounded domain. We introduce here two localization procedures resulting from the combination of this limit perturbation model with each of the following inversion processes： the Current Projection method and an Inverse Fourier method. Each localization procedure uses, as data, a finite number of boundary measurements, and is employed in the single inhomogeneity case; only the one based on an Inverse Fourier method is required in the multiple inhomogeneities case. Our localization approach is numerically suitable for the context of inhomogeneities that are not purely electric. We compare the numerical results obtained from the two localization procedures in the single inhomogeneity configuration, and describe, in various settings of multiple inhomogeneities, the results provided by the procedure based on an Inverse Fourier method.

关键词： Inverse problems Maxwell equations Electric fields Inhomogeneities Elec-trical Impedance Tomography Current Projection method FFT Numerical boundarymeasurements Edge elements Least square systems Incomplete Modified Gram-schmidt preconditioning.

NUMERICAL LOCALIZATION OF ELECTROMAGNETIC IMPERFECTIONs FROM A PERTURBATION FORMULA IN THREE DIMENsIONs

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Journal of Computational Mathematics 2008年第2期26卷 149-195页

作者： M.Asch s.M.mefire LAMFA Université de PicardieCNRs33rue Saint-Leu80039 AmiensFrance CMAP Ecole PolytechniqueCNRSRoute de Saclay91128 PalaiseauFrance

This work deals with the numerical localization of small electromagnetic inhomogeneities. The underlying inverse problem considers, in a three-dimensional bounded domain, the time-harmonic Maxwell equations formulated in electric field. Typically, the domain contains a finite number of unknown inhomogeneities of small volume and the inverse problem attempts to localize these inhomogeneities from a finite number of boundary measurements. Our localization approach is based on a recent framework that uses an asymptotic expansion for the perturbations in the tangential boundary trace of the curl of the electric field. We present three numerical localization procedures resulting from the combination of this asymptotic expansion with each of the following inversion algorithms： the Current Projection method, the MUltiple signal Classification （MUsIC） algorithm, and an Inverse Fourier method. We perform a numerical study of the asymptotic expansion and compare the numerical results obtained from the three localization procedures in different settings.

关键词： Inverse problems Maxwell equations Electric fields Three-dimensional inho-mogeneities Electrical impedance tomography Current projection method MUsIC algo-rithm FFT Edge elements Numerical boundary measurements

sTATIC REGIME IMAGING OF LOCATIONs OF CERTAIN 3D ELECTROMAGNETIC IMPERFECTIONs FROM A BOUNDARY PERTURBATION FORMULA

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Journal of Computational Mathematics 2014年第4期32卷 412-441页

作者： seraphin M. mefire IECL CNRS UMR 7502 Universite de Lorraine Faculte des Sciences et Technologies de Nancy 54506 Vandoeuvre-les-Nancy Cedex France

We are concerned, in a static regime, with a three-dimensional bounded domain of certain an imaging approach of the locations in electromagnetic imperfections. This approach is related to Electrical Impedance Tomography and makes use of a new perturbation formula in the electric fields. We present two localization procedures, from a Current Pro- jection method that deals with the single imperfection context and an inverse Fourier process that is devoted to multiple imperfections configurations. These procedures extend those that were described in our previous work, since operating for a broader class of settings. Namely, the localization is additionally performed for certain purely electric imperfections, as established from numerical simulations.

关键词： Inverse problems Maxwell equations Electric fields Inhomogeneities Elec-trical lmpedanee Tomography Current Projection method FFT Numerical boundarymeasurements Random noise Edge elements Least square systems Incomplete ModifiedGram-schmidt preconditioning.

Numerical study of switching Behavior in Finite Media subject to 3D Ferroelectric-Paraelectric Interactions and Inspection of Calibration Effects

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Numerical Mathematics(Theory,Methods and Applications) 2021年第1期14卷 113-143页

作者： P.-W.Martelli s.M.mefire Universite de Lorraine CNRSIECLF-54000 NancyFrance

We study numerically the switching behavior aspects and calibration effects relative to finite media embedding fully a three-dimensional ferroelectric layer in a paraelectric *** approach makes use of the Ginzburg-Landau formalism in combination with the electrostatics *** associated discrete nonlinear system,which arises from finite element approximations,is solved by an inexact Newton *** resulting numerical experiments highlight the effects of a balance between the physical and geometrical *** particular,the same state switchings can be retrieved from different ferroelectric layer sizes by acting upon the physical characteristic of the paraelectric *** platelet samples are in parallelepipedic and cylindrical configurations involved in these experiments.

关键词： Electroactive media ferroelectricity electrostatics Ginzburg-Landau systems finite elements inexact Newton methods numerical simulations

Numerical study of solutions of the 3D Generalized Kadomtsev-Petviashvili Equations for Long Times

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Communications in Computational Physics 2009年第10期6卷 1022-1062页

作者： F.Hamidouche Y.Mammeri s.M.mefire Laboratoire de Mathematiques CNRS UMR 8628Universite Paris-Sud 1191405 Orsay CedexFrance Laboratoire de Mathematiques–Paul Painleve CNRS UMR 8524Universite des Sciences et Technologies de Lille59655 Villeneuve d’Ascq CedexFrance Laboratoire Amienois de Mathematique Fondamentale et Appliquee CNRS UMR 6140Universite de Picardie33 r.Saint-Leu80039 Amiens Cedex 1France

From a spectral method combined with a predictor-corrector scheme,we numerically study the behavior in time of solutions of the three-dimensional generalized Kadomtsev-Petviashvili *** a systematic way,the dispersion,... 详细信息

关键词： 3D-KP equations spectral method predictor-corrector method dispersion blow-up soliton transverse instability

Revisiting cerebral endothelial cells in Alzheimer’s disease

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Neural Regeneration Research 2025年第10期20卷 2911-2912页

作者： Amira s.Hanafy Department of Neurosurgery University Hospital BonnBonnGermany

Alzheimer’s disease(AD)is the most common neurodegenerative disorder characterized by slow and progressive decline of cognitive and memory *** only approximately 5%of the cases,AD is familial,as often predisposed by genetic mutations(Hoogmartens et al.,2021),while sporadic AD accounts for approximately 95%of the *** amyloid cascade hypothesis is one of the fundamental hypotheses put out to explain AD pathogenesis as dysregulated homeostasis of amyloid-β(Aβ)peptides that leads to the accumulation of Aβplaques in the parenchyma,an anatomical hallmark of AD.

关键词： Alzheimer Aβ cerebral

A systematic review of progenitor survival and maturation in Parkinsonian models

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Neural Regeneration Research 2025年第11期20卷 3172-3178页

作者： Giulia Comini Eilís Dowd Pharmacology&Therapeutics and Galway Neuroscience Center University of GalwayGalwayIreland

stem cell-based brain repair is a promising emergent therapy for Parkinson's disease based on years of foundational research using human fetal donors as a cell *** current therapeutic options for patients,this approach has the potential to provide longterm stem cell–derived reconstruction and restoration of the dopaminergic input to denervated regions of the brain allowing for restoration of certain functions to *** ultimate clinical success of stem cell–derived brain repair will depend on both the safety and efficacy of the approach and the latter is dependent on the ability of the transplanted cells to survive and differentiate into functional dopaminergic neurons in the Parkinsonian *** the pre-clinical literature suggests that there is considerable variability in survival and differentiation between studies,the aim of this systematic review was to assess these parameters in human stem cell-derived dopaminergic progenitor transplant studies in animal models of Parkinson's disease.A defined systematic search of the PubMed database was completed to identify relevant studies published up to March *** screening,76 articles were included in the analysis from which 178 separate transplant studies were *** these,graft survival could be assessed in 52 studies and differentiation in 129 ***,we found that graft survival ranged froms transplanted,with a median of 51%of transplanted cells surviving in the brain;while dopaminergic differentiation of the cells ranged from 0% to 46% of cells transplanted with a median of 3%.This systematic review suggests that there is considerable scope for improvement in the differentiation of stem cell-derived dopaminergic progenitors to maximize the therapeutic potential of this approach for patients.

关键词： cell replacement therapy differentiation embryonic stem cells graft induced pluripotent stem cells Parkinson's disease survival transplant

Deciphering the mechanobiology of microglia in traumatic brain injury with advanced microsystems

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Neural Regeneration Research 2025年第8期20卷 2304-2306页

作者： Anthony Procès sylvain Gabriele Univ.Grenoble Alpes InsermU1216Grenoble Institut des NeurosciencesGrenobleFrance Mechanobiology&Biomaterials Group CIRMAPResearch Institute for BiosciencesUniversity of MonsMonsBelgium

Advanced microsystems in traumatic brain injury research:Traumatic brain injury(TBI)results from a mechanical insult to the brain,leading to neuronal and axonal damage and subsequently causing a secondary *** minutes ... 详细信息

关键词： traumatic injury damage

Emerging structures and dynamic mechanisms ofγ-secretase for Alzheimer’s disease

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Neural Regeneration Research 2025年第1期20卷 174-180页

作者： Yinglong Miao Michael s.Wolfe Computational Medicine Program and Department of Pharmacology University of North Carolina–Chapel HillChapel HillNCUSA Department of Medicinal Chemistry University of KansasLawrenceKSUSA

γ-secretase,called“the proteasome of the membrane,”is a membrane-embedded protease complex that cleaves 150+peptide substrates with central roles in biology and medicine,including amyloid precursor protein and the Notch family of cell-surface *** inγ-secretase and amyloid precursor protein lead to early-onset familial Alzheimer’s disease.γ-secretase has thus served as a critical drug target for treating familial Alzheimer’s disease and the more common late-onset Alzheimer’s disease as ***,critical gaps remain in understanding the mechanisms of processive proteolysis of substrates,the effects of familial Alzheimer’s disease mutations,and allosteric modulation of substrate cleavage byγ-*** this review,we focus on recent studies of structural dynamic mechanisms ofγ-*** mechanisms,including the“Fit-stay-Trim,”“sliding-Unwinding,”and“Tilting-Unwinding,”have been proposed for substrate proteolysis of amyloid precursor protein byγ-secretase based on all-atom molecular dynamics *** an incorrect registry of the Notch1 substrate was identified in the cryo-electron microscopy structure of Notch1-boundγ-secretase,molecular dynamics simulations on a resolved model of Notch1-boundγ-secretase that was reconstructed using the amyloid precursor protein-boundγ-secretase as a template successfully capturedγ-secretase activation for proper cleavages of both wildtype and mutant Notch,being consistent with biochemical experimental *** approach could be potentially applied to decipher the processing mechanisms of various substrates byγ-*** addition,controversy over the effects of familial Alzheimer’s disease mutations,particularly the issue of whether they stabilize or destabilizeγ-secretase-substrate complexes,is ***,an outlook is provided for future studies ofγ-secretase,including pathways of substrate binding and product release,effects of modulators on familial Alzheimer’s disease mutations

关键词： Alzheimer’s disease amyloid precursor protein cryo-EM structures drug design intramembrane proteolysis molecular dynamics Notch