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Dirac Concentrations in a Chemostat Model of Adaptive Evolution(In honor of the immense scientific influence of Ham Brezis)

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Chinese Annals of Mathematics,Series B 2017年第2期38卷 513-538页

作者： Alexander LORZ benoit perthame Cécile TAING Sorbonne Universits UPMC Univ Paris 06InriaLaboratoire Jacques-Louis Lions UM R CNRS 7598F75005 ParisFrance

This paper deals with a non-local parabolic equation of Lotka-Volterra type that describes the evolution of phenotypically structured populations. Nonlinearities appear in these systems to model interactions and competition phenomena leading to selection. In this paper, the equation on the structured population is coupled with a differential equation on the nutrient concentration that changes as the total population *** methods aimed at showing the convergence of the solutions to a moving Dirac mass are reviewed. Using either weak or strong regularity assumptions, the authors study the concentration of the solution. To this end, BV estimates in time on appropriate quantities are stated, and a constrained Hamilton-Jacobi equation to identify where the solutions concentrates as Dirac masses is derived.

关键词： Adaptive evolution, Asymptotic behaviour, Chemostat, Dirac concentrations,Hamilton-Jacobi equations, Lotka-Volterra equations, Viscosity solutions

Analysis of a System Describing Proliferative-Quiescent Cell Dynamics

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Chinese Annals of Mathematics,Series B 2018年第2期39卷 345-356页

作者： Jean CLAIRAMBAULT benoit perthame Andrada Quillas MARAN Dedicated to Philippe G. Ciarlet on the occasion of his 80th birthda

Systems describing the dynamics of proliferative and quiescent cells are commonly used as computational models, for instance for tumor growth and *** on the very earliest stages of hematopoiesis, stem cells and early progenitors, the authors introduce a new method, based on an energy/Lyapunov functional to analyze the long time behavior of solutions. Compared to existing works, the method in this paper has the advantage that it can be extended to more complex situations. The authors treat a system with space variable and diffusion, and then adapt the energy functional to models with three equations.

关键词： Stability analysis Lyapunov functional Energy method Parabolic sys-tems Proliferative and quiescent cells Tumor growth Hematopoiesis

Composite Waves for a Cell Population System Modeling Tumor Growth and Invasion

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Chinese Annals of Mathematics,Series B 2013年第2期34卷 295-318页

作者： Min TANG Nicolas VAUCHELET Ibrahim CHEDDAD Irene VIGNON-CLEMENTEL Dirk DRASDO benoit perthame Department of mathematics Institute of Natural Sciences and MOE-LSCShanghai Jiao Tong University INRIA Paris Rocquencourt ParisFrance Laboratoire Jacques-Louis Lions UPMC Univ Paris 06 and CNRS UMR 7598F-75005ParisFrance

In the recent biomechanical theory of cancer growth,solid tumors are considered as liquid-like materials comprising elastic *** this fluid mechanical view,the expansion ability of a solid tumor into a host tissue is mainly driven by either the cell diffusion constant or the cell division rate,with the latter depending on the local cell density(contact inhibition) or/and on the mechanical stress in the *** the two by two degenerate parabolic/elliptic reaction-diffusion system that results from this modeling,the authors prove that there are always traveling waves above a minimal speed,and analyse their *** appear to be complex with composite shapes and *** small parameters allow for analytical solutions,and in particular,the incompressible cells limit is very singular and related to the Hele-Shaw *** singular traveling waves are recovered numerically.

关键词： Traveling waves Reaction-diffusion Tumor growth Elastic material

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什么是退化抛物-双曲型方程的动理学解？

数学译林 2012年第4期31卷 343-345,342页

作者：陈贵强 benoit perthame 甘在会(译) 陆柱家(校)

非线性退化抛物一双曲型方程是最重要的几类非线性偏微分方程之一．非线性与退化性是这些方程的两个主要特征，它们产生了一些异乎寻常的现象，这些现象需要用新的数学思想、方法和理论来加以解释．另一方面，由于这类方程在实际应用中... 详细信息

非线性退化抛物一双曲型方程是最重要的几类非线性偏微分方程之一．非线性与退化性是这些方程的两个主要特征，它们产生了一些异乎寻常的现象，这些现象需要用新的数学思想、方法和理论来加以解释．另一方面，由于这类方程在实际应用中的重要性，已有了有关计算此类方程的解的各种数值方法的设计与分析的大量文献．此外，此类方程解的适定性理论（存在性、唯一性和稳定性）的研究更迫在眉睫．

关键词：双曲型方程退化性抛物非线性偏微分方程动理学线性退化数学思想数值方法

Ubiquitination-mediated regulation of receptorlike kinases in symbiosis and immunity

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Molecular Plant 2024年第9期17卷 1335-1337页

作者： David Landry and benoit Lefebvre Laboratory of Plant-Microbe-Environment Interactions(LIPME) Universite de ToulouseINRAECNRS31326Castanet-TolosanFrance

Receptor-like kinases(RLKs)are plasma membrane(PM)proteins that monitor the extracellular environment and regulate various processes such as biotic *** motif(LysM)RLKs are a specific class of RLKs involved in the recognition of chitin-derived molecules produced by microorganisms(Buendia et al.,2018).Notably,the LysM-RLK heterocomplex LjNFR1/LjNFR5 recognizes lipochitooligosaccharides(LCOs,also called Nod factors)leading to root nodule symbiosis(RNS)in Lotus japonicus,whereas the heterocomplexes AtLYK5/AtCERK1 and OsCEBIP/OsCERK1 recognize chitooligosaccharides(COs)leading to defense responses in Arabidopsis thaliana and rice,respectively(Buendia et al.,2018).These receptors function as *** ligand binding activates the intracellular kinase activity of LjNFR1,AtCERK1,and OsCERK1,which mediate phosphorylation-dependent signaling cascades.

关键词： extracellular immunity kinases

Spatially resolved investigation of flame particle interaction in a two dimensional model packed bed

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Particuology 2024年第2期85卷 167-185页

作者： Mohammadhassan Khodsiani Reza Namdar Fathollah Varnik Frank Beyrau benoit Fond Institute of Fluid Dynamics and Thermodynamics Universitaetsplatz 2Magdeburg39106Saxony-AnhaltGermany Interdisciplinary Centre for Advanced Materials Simulation(ICAMS) Ruhr-University BochumBochum44801Germany ONERA The French Aerospace Lab Department of AerodynamicsAeroelasticity and Acoustics(DAAA)Paris-Saclay UniversityMeudon92190France

This study investigates the interaction between a premixed methane-air flame and particles inside a model packed *** opacity of the spherical packed beds to visible light poses a major barrier to the implementation of highly resolved optical diagnostics,so that no detailed experimental data were so far available for the validation of numerical ***,a two-dimensional cylindrical packed bed design is set up,which enables direct line-of-sight optical measurements without loss of spatial reso-lution over the fluid region between the *** this study,the case of cold metallic cylindrical particles(T=377 K)relevant to start-up of a reactor is investigated using internal particle cooling,which also allows cylinder specific heat transfer rate measurements by differential temperature measurements on the coolant *** two dimensional assumption is first verified by measuring the inflow ve-locity and cylinder temperature profile along the *** imaging is then per-formed using a telecentric lens to observe the position and geometry of the two-dimensional flame front with respect to the surrounding cylinders without loss of ***,the cylinder-specific flame to cylinder heat transfer rates and cylinder surface temperature are *** the flame is closely surrounded by the three cooled cylinders,intense heat transfer is observed in this region corresponding to 25±2.5%of the flame thermal *** were stabilised at different positions depending on inflow velocity and equivalence ratio,and a direct correlation between flame to cylinder stand-off distance and the heat transfer rate normalised to the flame thermal power was found for both top and side ***,sidewall quenching distances to the curved cylinder surfaces were evaluated,and seem to be influenced by the presence of a warm recirculation zone behind the *** investigation provides fully resolved flame front position and heat tra

关键词： Packed beds Flame-particle interaction Optical diagnostics Sidewall quenching

Effect of Processing and Cultivar on Thermo-Chemical Properties of Australian-Grown Hemp Hurd(Cannabis sativa L.)

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Journal of Renewable Materials 2024年第8期12卷 1475-1493页

作者： Johannes Fehrmann benoit Belleville Barbara Ozarska Maya Ismayati Wahyu Dwianto School of Agriculture Food and Ecosystem Sciences(SAFES)Faculty of ScienceThe University of MelbourneMelbourne3121Australia Research Center for Biomass and Bioproducts National Research and Innovation Agency(BRIN)Jakarta16911Indonesia

This study explored the thermo-chemical properties of industrial hemp hurd with different provenances,maturity stages,and retting *** findings were then compared to hemp hurd used in the fabrication of citric acid-bonded ultra-low-density hemp hurd ***-gas chromatography-mass spectrometry(Py-GC/MS),Fourier-transform infrared spectroscopy(FTIR),and thermogravimetric analysis(TGA)were employed to document the variability of the hurd and comprehend the potential impact on biobased composite *** choice of cultivar,maturity stage,and processing modality significantly influenced the chemical composition,presence of functional groups,and thermal stability of the ***-GC/MS revealed substantial variations in the lignin-to-carbohydrate(L/C)ratio,along with the absence of fatty acids in certain *** FTIR signals confirmed consistent functional groups,differences in peak intensities were indicative of carbohydrate variations associated with maturity and retting duration,impacting the availability of hydroxyl groups for,i.e.,interparticle bonding in citric acid-based ***,it was observed that shorter retting durations initially enhanced the thermal resistance,but prolonged retting led to accelerated degradation,significantly reducing the hurd’s residual *** findings indicated notable differences among the samples,emphasizing the importance of investigating variables such as provenance/cultivar,maturity,and processing *** assessment is essential to ensure effective agronomic practices that align the raw material characteristics with the specific requirements of intended applications,such as the fabrication of biobased hemp hurd composites.

关键词： Hemp hurd material characterization chemical analysis thermal analysis

Multi-point temperature measurements in packed beds using phosphor thermometry and ray tracing simulations

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Particuology 2024年第2期85卷 77-88页

作者： Guangtao Xuan Mirko Ebert Simson Julian Rodrigues Nicole Vorhauer-Huget Christian Lessig benoit Fond Institute of Fluid Dynamics and Thermodynamics OVGU MagdeburgUniversitaetsplatz 2Magdeburg39106Saxony-AnhaltGermany Institute of Simulations and Graphics OVGU MagdeburgUniversitaetsplatz 2Magdeburg39106Saxony-AnhaltGermany Institute of Process Engineering OVGU MagdeburgUniversitaetsplatz 2Magdeburg39106Saxony-AnhaltGermany ONERA The French Aerospace LabDepartment of AerodynamicsAeroelasticity and Aeroacoustics(DAAA)Paris-Saclay University8rue des VertugadinsMeudon92190France

Packed bed reactors are commonly found in the process industry,for example in flame-assisted calci-nation for cement *** the heat transfer inside the bed is essential for process control,product quality and energy *** we propose a technique to determine the internal temperature distribution of packed beds based on a combination of lifetime-based phosphor ther-mometry,ray tracing simulations,and assimilation of temperature data using finite element heat transfer *** establish and validate the technique,we considered a reproducible regular packing of 6 mm diameter aluminum spheres,with one of the spheres in the top layer being electrically *** a sphere inside the packing is coated with thermographic phosphors and excitation light is directed to-wards the packing,luminescence from the coated sphere exits the packed bed after multiple reflection and the sphere's temperature can be *** measurements showed that the temper-ature obtained by phosphor thermometry is independent of the luminescent sphere *** imaging the luminescence on a camera,the luminescence distribution in recorded image depended,however,on the position of the ***,in setups with multiple phosphor-coated spheres,their signals can be separated using a least squares *** demonstrate the approach using a setup with three luminescent spheres and validated the temperature readings against thermocouple *** obtain the spatial signatures for individual sphere positions required for the least squares fit,ray tracing simulations were *** provide an efficient alternative to single sphere measurements that are only practical for regular spherical packed ***-point measurements were used as input to a finite element heat transfer simulations to determine parameters such as particle-to-particle air gap *** these,the full temperature distribution inside the bed could be assimilated from the meas

关键词： Packed beds Phosphor thermometry Ray tracing Heat transfer simulation Data assimilation

Matrix Assisted Laser Desorption Ionization Time of Flight(MALDI-TOF)-Mass Spectrometry and^(13)C-NMR-Identified New Compounds in Paraberlinia bifoliolata(Ekop-Beli)Bark Tannins

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Journal of Renewable Materials 2024年第3期12卷 553-568页

作者： Liliane Nga benoit Ndiwe Achille Bernard Biwolé Antonio Pizzi Jean Jalin Eyinga Biwole Joseph Zobo Mfomo Laboratory of Forest Resources and Wood Valorization Training Unit in Engineering SciencesPost Graduate School of Fundamental and Applied SciencesUniversity of DoualaP.O.Box 1872DoualaCameroun Laboratory of Mechanics Training Unit in Engineering SciencesPost Graduate School of Fundamental and Applied SciencesUniversity of DoualaP.O.Box 2701DoualaCameroun Laboratory of Studies and Research on Wood Material(LERMAB) University of LorraineNancyFrance

Extracts of plant origin,particularly tannins,are attracting growing interest for the sustainable development of materials in the industrial *** discovery of new tannins is therefore *** aim of this work was to contribute to the understanding of the properties of Paraberlinia bifoliolata tannin by Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectroscopy MALDI-TOF/MS and Carbon 13 Nuclear Magnetic Resonance(13C NMR).The chemical composition of tannin extracted from Paraberlinia bifoliolata bark was determined,as was the mechanical strength of the resin hardened with Acacia nilotica *** by successive water extraction was 35%.MALDI-TOF/MS analysis revealed the presence of three new compounds in this tannin,previously unknown in this family of *** are 3-hydroxyproline acid,N-methyl-4-hydroxypipecolic acid and N-methyl-5-dihydroxypipecolic *** identification of the above molecules means that this tannin can be used for industrial applications,as a resin in the manufacture of particleboard and in the formulation of green corrosion *** information is reinforced by 13C NMR spectrometry,which indicates the presence of several polyflavonoid units,confirming the condensed nature of the *** analysis of the resin formed by the purified tannin of Paraberlinia bifoliolata to which a vegetal biohardener has been added provided a Modulus of Elasticity(MOE)value of 4840 MPa at 150℃,confirming its possible use as a binder resin in the manufacture of wood panels as well as for the formulation of a corrosion inhibitor.

关键词： Tannin Paraberlinia bifoliolata Central African wood species MALDI-TOF/MS 13C NMR bark extracts thermomechanical behaviour wood-binder