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Sparse Approximations of the Schur Complement for Parallel Algebraic Hybrid Solvers in 3D

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Numerical Mathematics(Theory,Methods and Applications) 2010年第3期3卷 276-294页

作者： L.giraud A.Haidar Y.Saad Joint INRIA-CERFACS Lab-42 AV.Coriolis 31057ToulouseFrance Department of Computer Science University of TennesseeKnoxvilleTN37996USA. Department of Computer Science and Engineering University of MinnesotaMinneapolisMN55455USA

In this paper we study the computational performance of variants of an algebraic additive Schwarz preconditioner for the Schur complement for the solution of large sparse linear *** earlier works,the local Schur complements were computed exactly using a sparse direct *** robustness of the preconditioner comes at the price of this memory and time intensive computation that is the main bottleneck of the approach for tackling huge *** this work we investigate the use of sparse approximation of the dense local Schur *** approximations are computed using a partial incomplete LU *** a numerical calculation is the core of the multi-level incomplete factorization such as the one implemented in pARMS. The numerical and computing performance of the new numerical scheme is illustrated on a set of large 3D convection-diffusion problems;preliminary experiments on linear systems arising from structural mechanics are also reported.

关键词： Hybrid direct/iterative solver domain decomposition incomplete/partial factorization Schur approximation scalable preconditioner convection-diffusion large 3D problems parallelscientific computing High Performance Computing.

Tubulointerstitial injury and proximal tubule albumin transport in early diabetic nephropathy induced by type 1 diabetes mellitus

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BIOCELL 2017年第1期41卷 1-12页

作者： Maximiliano giraud-BILLOUD Fernando EZQUER Javiera BAHAMONDE Marcelo EZQUER IHEM Universidad Nacional de CuyoCONICETFacultad de Ciencias MédicasMendozaArgentina Centro de Medicina Regenerativa Facultad de Medicina Clínica AlemanaUniversidad del DesarrolloAvenida Las Condes 12438SantiagoChile

A decrease in the tubular expression of albumin endocytic transporters megalin and cubilin has been associated with diabetic nephropathy,but there are no comprehensive studies to date relating early tubulointerstitial injury and the effect of the disease on both transporters in type 1 diabetes mellitus(T1DM).We used eight-week-old male C57BL/6 mice divided into two groups;one of them received the vehicle(control group),while the other received the vehicle+200 mg/kg streptozotocin(T1DM).Ten weeks after the injection,we evaluated plasma insulin,enzymuria,urinary vitamin D-binding protein(VDBP),tubulointerstitial fibrosis and proximal tubule histology,markers of autophagy,and megalin and cubilin *** found a reduction in tubular protein reabsorption(albumin and VDBP as specific substances carried by both transporters)with increased tubulointerstitial injury,development of fibrosis,thickening of tubular basement membrane,and an increase in tubular cell *** was associated with a decrease in the renal expression of megalin and *** also observed an increase in the amount of cellular vesicles of the phagocytic system in the tubules,which could be linked to an alteration of normal intracellular trafficking of both receptors,thus affecting the normal function of transporters in early stages of diabetic *** diabetic animals,the added effects of tubulointerstitial injury,the decreases in megalin and cubilin expression,and an altered intracellular trafficking of these receptors,seriously affect protein reabsorption.

关键词： Albuminuria Megalin Cubilin Autophagy

A composite sphere assemblage model for porous oolitic rocks:Application to thermal conductivity

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第1期9卷 54-61页

作者： F. Chen A. giraud D. Grgic K. Kalo Geo Ressources Laboratory Université de Lorraine (ENSG) CNRS CREGU Vandoeuvre-lès-Nancy F-54518 France

The present work is devoted to the determination of linear effective thermal conductivity of porous rocks characterized by an assemblage of grains(oolites) coated by a matrix. Two distinct classes of pores, *** or intra oolitic pores(oolite porosity) and mesopores or inter oolitic pores(inter oolite porosity), are taken into account. The overall porosity is supposed to be connected and decomposed into oolite porosity and matrix porosity. Within the framework of Hashin composite sphere assemblage(CSA)models, a two-step homogenization method is developed. At the first homogenization step, pores are assembled into two layers by using self-consistent scheme(SCS). At the second step, the two porous layers constituting the oolites and the matrix are assembled by using generalized self-consistent scheme(GSCS) and referred to as three-phase model. Numerical results are presented for data representative of a porous oolitic limestone. It is shown that the influence of porosity on the overall thermal conductivity of such materials may be significant.

关键词： Effective thermal conductivity Three-phase model Oolitic limestone Composite sphere assemblage(CSA) model

Urine-derived stem/progenitor cells:A focus on their characterization and potential

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World Journal of Stem Cells 2020年第10期12卷 1080-1096页

作者： Perrine Burdeyron Sébastien giraud Thierry Hauet Clara Steichen INSERM U1082 IRTOMIT CHU de PoitiersPoitiers 86021France Facultéde Médecine et Pharmacie Universite de PoitiersPoitiers 86021France

Cell therapy,i.e.,the use of cells to repair an affected tissue or organ,is at the forefront of regenerative and personalized *** the multiple cell types that have been used for this purpose[including adult stem cells such as mesenchymal stem cells or pluripotent stem cells],urine-derived stem cells(USCs)have aroused interest in the past *** display classical features of mesenchymal stem cells such as differentiation capacity and ***,they have the main advantage of being isolable from one sample of voided urine with a cheap and unpainful procedure,which is broadly applicable,whereas most adult stem cell types require invasive ***,USCs can be differentiated into renal cell *** is of high interest for renal cell therapy-based regenerative *** review will firstly describe the isolation and characterization of *** will specifically present USC phenotype,which is not an object of consensus in the literature,as well as detail their differentiation *** the second part of this review,we will present and discuss the main applications of *** include use as a substrate to generate human induced pluripotent stem cells,but we will deeply focus on the use of USCs for cell therapy approaches with a detailed analysis depending on the targeted organ or ***,we will also focus on the applications that rely on the use of USC-derived products such as microvesicles including exosomes,which is a strategy being increasingly *** the last section,we will discuss the remaining barriers and challenges in the field of USC-based regenerative medicine.

关键词： Urine-derived stem cells Urine progenitor cells Exosomes Cell therapy Kidney injury and repair Regenerative medicine

Defining the Mitochondrial Stress Response in Arabidopsis thaliana

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Molecular Plant 2009年第6期2卷 1310-1324页

作者： Olivier Van Aken Botao Zhang Chris Carrie Vindya Uggalla Ellen Paynter Estelle giraud James Whelan ARC Centre of Excellence in Plant Energy Biology MCS Building M316 University of Western Australia 35 Stirling Highway Crawley 6009 Western AustraliaAustralia

To obtain a global overview of how mitochondria respond to stress, we aimed to define the plant mitochondrial stress response （MSR）. By combining a set of 1196 Arabidopsis thaliana genes that putatively encode mitochondrial proteins with 16 microarray experiments on stress-related conditions, 45 nuclear encoded genes were defined as widely stress-responsive. Using green fluorescent protein （GFP） fusion assays, the mitochondrial targeting of a large number of these proteins was tested, confirming in total 26 proteins as mitochondrially targeted. Several of these proteins were observed to be dual targeted to mitochondria and plastids, including the small heat shock proteins sHSP23.5 and sHSP23.6. In addition to the well defined stress components of mitochondria, such as alternative oxidases, nicotinamide adenine dinudeotide （NAD（P）H） dehydrogenases, and heat shock proteins, a variety of other proteins, many with unknown function, were identified. The mitochondrial carrier protein family was over-represented in the stress-responsive genes, suggesting that stress induces altered needs for metabolite transport across the mitochondrial inner membrane. Although the genes encoding many of these proteins contain common cis-acting regulatory elements, it was apparent that a number of distinct regulatory processes or signals likely triggered the MSR. Therefore, these genes provide new model systems to study mitochondrial retrograde regulation, in addition to the widely used alternative oxidase model. Additionally, as changes in proteins responsive to stress did not correlate well with changes at a transcript level, it suggests that post-transcriptional mechanisms also play an important role in defining the MSR.

关键词： enzymes genes green fluorescent protein heat shock proteins mitochondria oxidoreductases plant proteins plastids stress stress response Arabidopsis thaliana Genes Heat Shock Proteins Plastid stress response Arabidopsis thaliana Oxidoreductases Plant Proteins Proteins Enzymes Mitochondria Green Fluorescent Proteins

Low-ionization galaxies and evolution in a pilot survey up to z=1

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Research in Astronomy and Astrophysics 2011年第3期11卷 245-270页

作者： Edmond giraud Qiu-Sheng Gu Jorge Melnick Hernan Quintana Fernando Selman Ignacio Toledo Paula Zelaya LPTA Universit6 Montpellier 2 - CNRS/IN2P3 34095 Montpellier France edmond.giraud@ lpta. in2p3.fr Department of Astronomy Nanjing University Nanjing 210093 China European Southern Observatory /klonso de Cbrdova 3107 Santiago Chile Department of Astronomy and Astrophysics R Universidad Catolica de Chile Casilla 306Santiago Chile

We present galactic spectroscopic data from a pencil beam of 10.75×7.5 centered on the X-ray cluster RXJ0054.0–2823 at z=*** study the spectral evolution of galaxies from z=1 down to the cluster redshift in a magnitude-limited sample at R≤23,for which the statistical properties of the sample are well *** divide emission-line galaxies into star-forming galaxies,Low Ionization Nuclear Emission line Regions（LINERs） ,and Seyferts by using emission-line ratios of[OII],Hβ,and[OIII],and derive stellar fractions from population synthesis models. We focus our analysis on absorption and low-ionization *** absorption-line galaxies,we recover the well-known result that these galaxies have had no detectable evolution since z～0.6-0.7,but we also find that in the range z=0.65-1,at least 50% of the stars in bright absorption systems are younger than 2.5 *** absorption-line galaxies in the cluster at z=0.29 also had significant star formation during the previous 2-3 Gyr,but their brighter counterparts seem to be only composed of old *** z～0.8,our dynamically young cluster had a truncated *** result seems to be consistent with a scenario where the final assembly of E/S0 took place at *** the volume-limited range 0.35≤z≤0.65,we find that 23% of the early-type galaxies have LINER-like spectra with Hβin absorption and have a significant component of A *** vast majority of LINERs in our sample have significant populations of young and intermediate-aged stars and are thus not related to AGNs,but to the population of‘retired galaxies’recently identified by Cid Fernandes et *** the Sloan Digital Sky Survey（SDSS） .Early-type LINERs with various fractions of A stars and E＋A galaxies appear to play an important role in the formation of the red sequence.

关键词： cosmology:observations—galaxies:evolution—large scale structures —evolution—RX J0054.0–2823

Assessing the impact of conceptual mineral systems uncertainty on prospectivity predictions

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Geoscience Frontiers 2022年第6期13卷 182-207页

作者： Mark D Lindsay Agnieszka M.Piechocka Mark W Jessell Richard Scalzo Jeremie giraud Guillaume Pirot Edward Cripps Commonwealth Scientific and Industrial Research Organisation Mineral Resources Australian Resources Research CentreWA 6151Australia Mineral Exploration Cooperative Research Centre Centre for Exploration TargetingSchool of Earth SciencesThe University of Western AustraliaPerthWA 6009Australia ARC Centre for Data Analytics for Resources and Environments(DARE) Perth and SydneyAustralia University of Sydney School of Mathematics and StatisticsSydneyAustralia Universitéde Lorraine GeoRessourcesCNRS54000 NancyFrance The University of Western Australia Department of Mathematics and StatisticsPerthAustralia

The past two decades have seen a rapid adoption of artificial intelligence methods applied to mineral exploration. More recently, the easier acquisition of some types of data has inspired a broad literature that has examined many machine learning and modelling techniques that combine exploration criteria,or ’features’, to generate predictions for mineral prospectivity. Central to the design of prospectivity models is a ’mineral system’, a conceptual model describing the key geological elements that control the timing and location of economic mineralisation. The mineral systems model defines what constitutes a training set, which features represent geological evidence of mineralisation, how features are engineered and what modelling methods are used. Mineral systems are knowledge-driven conceptual models, thus all parameter choices are subject to human biases and opinion so alternative models are ***, the effect of alternative mineral systems models on prospectivity is rarely compared despite the potential to heavily influence final predictions. In this study, we focus on the effect of conceptual uncertainty on Fe ore prospectivity models in the Hamersley region, Western Australia. Four important considerations are tested.(1) Five different supergene and hypogene conceptual mineral systems models guide the inputs for five forest-based classification prospectivity models model.(2) To represent conceptual uncertainty, the predictions are then combined for prospectivity model comparison.(3)Representation of three-dimensional objects as two-dimensional features are tested to address commonly ignored thickness of geological units.(4) The training dataset is composed of known economic mineralisation sites(deposits) as ’positive’ examples, and exploration drilling data providing ’negative’sampling locations. Each of the spatial predictions are assessed using independent performance metrics common to AI-based classification methods and subjected to geological pl

关键词： Uncertainty Modelling Prospectivity Economic geology Geological plausibility Forest-based classification

Diabetic nephropathy,autophagy and proximal tubule protein endocytic transport:A potentially harmful relationship

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BIOCELL 2018年第2期42卷 35-40页

作者： Maximiliano giraud-BILLOUD Claudio M.FADER Rocío AGÜERO Fernando EZQUER Marcelo EZQUER IHEM Universidad Nacional de CuyoCONICETMendozaArgentina Universidad Nacional de Cuyo Facultad de Ciencias MédicasInstituto de FisiologíaCasilla de Correo 335500-MendozaArgentina Universidad Nacional de Cuyo Facultad de OdontologíaCasilla de Correo 335500-MendozaArgentina Centro de Medicina Regenerativa Facultad de Medicina Clínica AlemanaUniversidad del DesarrolloAvenida Las Condes 12438SantiagoChile

Diabetic nephropathy(DN)is the most frequent cause of chronic renal *** now,the pathophysiological mechanisms that determine its development and progression have not yet been *** the present study,we evaluate the role of autophagy at early stages of DN,induced in type 2 diabetes mellitus(T2DM)mouse,and its association with proximal tubule membrane endocytic receptors,megalin and *** T2DM animals we observed a tubule-interstitial injury with significantly increased levels of urinary GGT and ALP,but an absence of tubulointerstitial *** proximal tubule cells of T2DM animals showed autophagic vesicles larger than those observed in the control group,and an increase in the number of these vesicles marked with LBPA by ***,a significant decrease in the ratio of LC3II/LC3I isoforms and in p62 protein expression in DN affected animals is ***,we observed a marked increase in urinary albumin and vitamin D binding-protein levels in T2DM animals as well as a significant decrease in expression of megalin in the renal *** results indicate an alteration of the tubular endocytic transporters in DN,which could be related to autophagic dysfunction,which would in turn result in impaired organelle recycling,thus contributing to the progression of this disease.

关键词： Megalin Cubilin Type 2 diabetes mellitus

Polyester-supported Chitosan-Poly(vinylidene fluoride)-Inorganic-Oxide-Nanoparticles Composites with Improved Flame Retardancy and Thermal Stability

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Chinese Journal of Polymer Science 2020年第1期38卷 84-91,I0007页

作者： Ahmed Abed Nabil Bouazizi Stephane giraud Ahmida El Achari Christine Campagne Olivier Thoumire Reddad El Moznine Omar Cherkaoui Julien Vieillard Abdelkrim Azzouz ENSAIT GEMTEX-Laboratoire de Genie et Materiaux TextilesF-59000 LilleFrance Laboratory LPMC Faculty of Science El JadidaChouaib Doukkali UniversityEl JadidaMorocco Laboratory REMTEX ESITHRouted'EI Jadidakm8BP 7731-OulfaCasablancaMorocco Normandie Univ. UNIROUENCNRSPBS(UMR 6270)55 rue Saint Germain27000 EvreuxFrance Normandie Univ. UNI ROUENINSA RouenCNRSCOBRA(UMR 6014)55 rue Saint Germain27000 EvreuxFrance Nanoqam Department of ChemistryUniversity of Quebec at MontrealQCCanada

Polyester(PET) was pre-activated by atmospheric air plasma and coated by various inorganic oxide nanoparticles(MOx) such as titanium dioxide(TiO2), zinc oxide(ZnO), and silicon oxide(SiO2), using poly(vinylidene fluoride)(PVDF) and chitosan(CT) as binders. The resulting PET-PVDF-MOx-CT composites were thermally compressed and then characterized by scanning electron microscopy, Fourier infrared spectroscopy, thermal gravimetric analysis, and flame retardancy(FR) ability tests. PET modifications resulted in more thermally stable and less harmful composites with weaker hazardous gas release. This was explained in terms of structure compaction that blocks pyrolysis gas *** incorporation was found to reduce the material susceptibility to oxidation. This judicious procedure also allowed improving flame retardancy ability, by lengthening the combustion delay and slowing the flame propagation. Chitosan also turned out to contribute to a possible synergy with the other polymers present in the synthesized materials. These results provide valuable data that allow understanding the FR phenomena and envisaging low-cost high FR materials from biodegradable raw materials.

关键词： Polyester nonwovens Composite PVDF Flame retardancy Material oxides Chitosan