References of "Plougonven, Erwan"
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See detailMediterranean aegagropiles from Posidonia oceanica (L.) Delile (1813): a frst complete description from macroscopic to microscopic structure
Lefebvre, Laurence ULiege; Compère, Philippe ULiege; Léonard, Angélique ULiege et al

in Marine Biology (2021), 168:37

Aegagropiles are round-shaped conglomerations of Posidonia oceanica debris commonly found along the coasts of the Mediterranean Sea. This study presents a detailed description of the composition of ... [more ▼]

Aegagropiles are round-shaped conglomerations of Posidonia oceanica debris commonly found along the coasts of the Mediterranean Sea. This study presents a detailed description of the composition of aegagropiles in terms of their internal organisation in different layers (and the orientation of the fibres in these layers), the proportion of constituent elements (fibres and minerals) and the histological (by way of microscopic observations) nature of all of these aegagropiles elements. The aim of this work is to take a detailed interest in the structure of the aegagropiles of Posidonia oceanica and to determine the process that forms them. Aegagropiles are an assemblage of two types of debris from the P. oceanica meadow: (1) plant- based: fibres more or less degraded from P. oceanica shoots (leaves and rhizomes) and (2) mineral particles such as silicates and biotic Ca-carbonate debris. On the basis of structural and compositional observations, we proposed an elucidation of the cycle in several phases: initiation of a “roll” by aggregation of litter fibres and sand in the ripple marks, growth, breakdown of the roll into small balls (microbial and mechanical degradation) and export of aegagropiles down (into the abyss) or on to the beaches. Calculations estimate that considering its density of 0.2 g/cm3, an aegagropile represents the accumulation of fibres from approximately 25 shoots of P. oceanica. [less ▲]

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See detailLocal adaptation of bone micro-structure and canal network to tendon insertion investigated by image-based micro-FE simulations
Tits, Alexandra ULiege; Varga, Peter; Volders, Timothy ULiege et al

in Bone Reports (2020, October), 13

Tendons anchor to bone through a multi-material region called enthesis, showing several strategies to cope with the challenging task of joining dissimilar tissues. Less understood is whether bone ... [more ▼]

Tendons anchor to bone through a multi-material region called enthesis, showing several strategies to cope with the challenging task of joining dissimilar tissues. Less understood is whether bone microstructure also displays specific features to facilitate force transmission from tendon to bone. Such knowledge is of clinical relevance as local mechanical stresses play a crucial role in avulsion fractures and interface pathologies. Here we characterized the microstructure of bone close to tendon insertion in calcanei of adult rats (n=5) with micro-computed tomography (SkyScan, Bruker; 5 to 1.2 micrometer voxel size). After aligning the virtual bones along the main axes of inertia, we investigated a bony tuberosity connecting the Achilles tendon with the plantar fascia ligament. We performed a spatially resolved analysis of trabecular microstructure, indicating that trabecular network (BV/TV and anisotropy) is not significantly influenced by the tendon insertion (P = 0.69). Conversely, high resolution images revealed that bone beneath the attachment region exhibits a highly oriented canal network, aligned with the pulling direction of the tendon (P b 0.005). Image-based micro-finite element analysis was used to calculate stresses within the bone induced by tendon loading. Simulations highlighted a non-trivial stress pattern within the bone with high stresses mainly flowing within the tuberosity (27% higher than in the rest of the bone, P b 0.005). Our work suggests that not only the enthesis but also the underlying bone is well-adapted to accommodate tendon loading. [less ▲]

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See detailFactors governing soil water repellency under tillage management: The role of pore structure and hydrophobic substances
Li, Shengping ULiege; Lu, Jinjing ULiege; Liang, Guopeng et al

in Land Degradation and Development (2020)

Soil water repellency (SWR) has significant effects on soil degradation by changing some soil processes (e.g., carbon sequestration and soil erosion). Understanding the influence factors of SWR under ... [more ▼]

Soil water repellency (SWR) has significant effects on soil degradation by changing some soil processes (e.g., carbon sequestration and soil erosion). Understanding the influence factors of SWR under conservation agriculture are playing a vital role in the sustainable development for improving soil quality. However, how soil pore structure influence on SWR remains unclear. We aim to assess the impact of hydrophobic substances and pore structure on SWR. Here we conducted two long‐term experimental fields with three treatments: conventional tillage (CT), reduced tillage (RT), and no‐tillage (NT). X‐ray tomography and the sorptivity method were used to measure soil pore structure and SWR, respectively. We found that soil organic carbon (SOC) and microbial biomass carbon (MBC) were higher in RT and NT treatments than in CT. MBC had significant influences on soil water sorptivity (Sw) and water repellency index (RI; p < 0.001), whereas SOC had no influence on Sw (p > 0.05). MBC also showed a closer relationship with SWR than SOC in redundancy analysis. The RT and NT increased the porosity of 55–165 μm that had a positive relationship with ethanol sorptivity and RI (p < 0.05). Ethanol sorptivity increased with an increase in soil pore porosity and connectivity under RT and NT treatments. However, increasing the pore surface area could decrease Sw due to enhance contact area between hydrophobic substances and soil water. Overall, the RT and NT treatments increased the water repellency index, which was a result of the interactions between pore structure and hydrophobic substances. [less ▲]

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See detailMicrostructural and micromechanical investigation of the tendon-bone attachment
Tits, Alexandra ULiege; KAUX, Jean-François ULiege; Plougonven, Erwan ULiege et al

Conference (2019, December 17)

We observed an evident bony tuberosity connecting the Achilles tendon with the plantar fascia ligament. We performed a spatially resolved analysis of trabecular microstructure, suggesting that trabecular ... [more ▼]

We observed an evident bony tuberosity connecting the Achilles tendon with the plantar fascia ligament. We performed a spatially resolved analysis of trabecular microstructure, suggesting that trabecular network was not significantly influenced by the tendon insertion. Conversely, bone beneath the attachment region showed a highly oriented canal network, aligned along the pulling direction of the tendon. Surface roughness was significantly higher at the tendon insertion with respect to nearby locations. Micro-FE simulations clarified the contributions of these different microstructural features to local stresses. [less ▲]

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See detailIn vitro and in vivo biocompatibility of calcium- phosphate scaffolds 3D printed by stereolithography for bone regeneration
Le Guéhennec, Laurent; Van hede, Dorien ULiege; Plougonven, Erwan ULiege et al

in Journal of Biomedical Materials Research. Part A (2019)

Stereolithography (SLA) is an interesting manufacturing technology to overcome limitations of commercially available particulated biomaterials dedicated to intra-oral bone regeneration applications. The ... [more ▼]

Stereolithography (SLA) is an interesting manufacturing technology to overcome limitations of commercially available particulated biomaterials dedicated to intra-oral bone regeneration applications. The purpose of this study was to evaluate the in vitro and in vivo biocompatibility and osteoinductive properties of two CaP-based scaffolds manufactured by SLA 3D printing. Pellets and macro-porous scaffolds were manufactured in pure hydroxyapatite (HA) and in biphasic CaP (HA:60-TCP:40). Physico- chemical characterization was performed using Micro X-ray Fluorescence (μXRF), Scanning Electron Microscopy (SEM), optical interferometry and microtomography (μCT) analyses. Osteoblast-like MG-63 cells were used to evaluate the biocompatibility of the pellets in vitro with MTS assay and the cell morphology and growth characterized by SEM and DAPI-actin staining showed similar early behavior. For in vivo biocompatibility, newly formed bone and biodegradability ofthe experimental scaffolds were evaluated in a subperiosteal cranial rat model using μCT and descriptive histology. The histological analysis has not indicated evidences of inflammation but highlighted close contacts between newly formed bone and the experimental biomaterials revealing an excellent scaffold osseointegration. This study emphasizes the relevance of SLA 3D printing of CaP-based biomaterials for intra-oral bone regeneration even if manufacturing accuracy has to be improved and further experiments using biomimetic scaffolds should be conducted. [less ▲]

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See detailOn the use of autocorrelation functions, permeability tensors, and computed tomography to characterize the anisotropy of diesel particulate filter materials
Bernard, Dominique; Léonard, Fabien; Plougonven, Erwan ULiege et al

Conference (2019, July 23)

We show how the combination of autocorrelation function and permeability calculations, applied to 3D X-ray computed tomography data, allows yielding quantitative information on the anisotropy of both ... [more ▼]

We show how the combination of autocorrelation function and permeability calculations, applied to 3D X-ray computed tomography data, allows yielding quantitative information on the anisotropy of both microstructure and fluid flow in Diesel Particulate Filter (DPF) materials.Several aspects about the meaning of the outputs of the autocorrelation function are discussed. [less ▲]

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See detailBiocompatibility of stereolithography 3D-printed calcium-phosphate scaffolds for bone regeneration
Van hede, Dorien ULiege; le Guehennec, Laurent; Plougonven, Erwan ULiege et al

Conference (2019, June 20)

Objectives: The aim of this study was to evaluate the in vitrobiocompatibility and in vivobehaviors of two CaP based scaffolds manufactured by stereolithography (SLA) 3D printing technology. Methods ... [more ▼]

Objectives: The aim of this study was to evaluate the in vitrobiocompatibility and in vivobehaviors of two CaP based scaffolds manufactured by stereolithography (SLA) 3D printing technology. Methods: Pellets and macro-porous scaffolds were manufactured respectively for the in vitroand the in vivoexperiments both in pure hydroxyapatite (HA) and in biphasic CaP (HA:60-TCP:40.) The in vitro cytocompatibility was assessed by cell culture using a human osteoblastic-like cell line (MG-63). MTS assays were performed in order to evaluate cell viability. Additionally, the cell morphology and growth were characterized using SEM as well as DAPI and Actin staining. In vivobiocompatibility, newly formed bone and biodegradability of the experimental scaffolds were evaluated 3 and 6 months after implantation in a subperiosteal cranial rat model. The sample were subjected to microtomography for quantitative analyses and then, to paraffin histology for a descriptive analysis. Results: In vitro, cell viability over 75% was found in both group and no statistical difference was found between the 2 biomaterials (p= 0,07). The cells displayed similar behavior, in terms of morphology and cell growth, independently of the scaffold type. The in vivo experiments revealed an excellent osteointegration of the scaffolds and a very limited biodegradability. After 3 months, the bone volume inside pores achieved 72,78% (± 17,87%) and 60,76% (± 23,78%) respectively for HA and HA-TCP. The histological analysis did not reveal signs of inflammation and highlighted close contacts between newly formed bone and the experimental biomaterials. Conclusions: This study emphasized that SLA-3D printing of CaP based biomaterials might be relevant for intra oral bone regeneration. The cytocompatibility and in vivobiological performances in terms of graft dimensional stability and osseointegration was demonstrated. However, further experiments in larger models should be conducted. [less ▲]

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See detailLoss of stromal galectin-1 enhances multiple myeloma development: Emphasis on a role in osteoclasts
Muller, Joséphine; Duray, Elodie ULiege; Lejeune, Margaux ULiege et al

in Cancers (2019), 11(2), 261

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See detailX-RAY COMPUTED TOMOGRAPHY: AN OUTSTANDING VISUALISATION TOOL FOR DRYING RESEARCH – Feedback on the last 20 years at University of Liège
Léonard, Angélique ULiege; Fraikin, Laurent ULiege; Plougonven, Erwan ULiege et al

in Barresi, Antonello (Ed.) Proceedings of the 7th European Drying Conference (2019)

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See detailRESORCINOL FORMALDEHYDE HYDROGEL DRYING BEHAVIOR: DESICCATION CRACKING MODELING
Hubert, Julien ULiege; Léonard, Angélique ULiege; Plougonven, Erwan ULiege et al

in Baressi, Antonello (Ed.) Proceedings of the 7th European Drying Conference (2019)

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See detailCan the pore scale geometry explain soil sample scale hydrodynamic properties?
Smet, Sarah ULiege; Beckers, Eléonore ULiege; Plougonven, Erwan ULiege et al

in Frontiers in Environmental Science (2018), 6(20),

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See detailStructures macroscopique et microscopique et formation des aegagropiles de Posidonia oceanica (L.) Delile (1813)
Lefebvre, Laurence ULiege; Gobert, Sylvie ULiege; Compère, Philippe ULiege et al

Poster (2018, April 11)

Il est courant de retrouver le long de plages de Méditerranée des agglomérations de débris végétaux originaire de l’herbier à Posidonies. Ces agglomérats portent le nom d’aegagropiles de P. oceanica ... [more ▼]

Il est courant de retrouver le long de plages de Méditerranée des agglomérations de débris végétaux originaire de l’herbier à Posidonies. Ces agglomérats portent le nom d’aegagropiles de P. oceanica , ceux-ci arborent des formes sphériques et ellipsoïdes. Les objectifs principaux de ce travail étaient d’identifier les différents composants des aegagropiles de P. oceanica et de déterminer la formation de ceux-ci. Pour ce faire, différentes analyses microscopiques (MET, MEB et MO) ont été effectuées ainsi que l’usage d’un mécanisme simulant la houle. Les observations en microscopie électronique à balayage ont été réalisées à l’aide de différents détecteurs (SSD et ETD) de SE et BSE, ce qui additionnés à diverses techniques de colorations et de contrastants ont permis de répondre à de nombreux objectifs. Les aegagropiles se forment par l’hydrodynamisme qu’engendre la houle et se composent d’un assemblage de débris végétaux provenant de P. oceanica ainsi que de grains de sable. Au fil des différentes étapes du cycle de la plante et de l’hydrodynamisme, les organes de la plante se rompent, s’accumulent au sein de la litière et subissent une combinaison de dégradations biotique et abiotique. Ces organes sont majoritairement des feuilles et des morceaux de rhizomes. La dégradation biotique est notamment engendrée par des champignons noirs septés nommés « Dark Septate Endophyte - DSE » qui, en s’attaquant spécifiquement à la lamelle mitoyenne des cellules permet des scissions longitudinales. La dégradation abiotique est quant à elle engendrée par les forces hydrodynamiques. Cette combinaison entraîne dès lors un lessivage important des différents organes végétaux qui se scindent et se courbent formant finalement de fines « fibres » qui s’accumuleront et s’entremêleront ensemble des ripples-marks afin d’élaborer des aegagropiles de P. oceanica. Les aegagropiles de P. oceanica se formeront initialement avec des débris intacts de rhizomes ou bien avec des faisceaux de fibres lignifiés ronds provenant également de ces rhizomes où de nombreux grains de nature minérale s’enchevêtreront à ces débris végétaux afin de constituer une structure initiale consolidée et résistante. Ensuite, d’autres débris végétaux, majoritairement de formes plates et provenant des feuilles et de gaines foliaires de P. oceanica , s’entremêleront à cette structure afin d’obtenir une agrégation allongée. Enfin, via une fragmentation aléatoire et des mouvements suivant préférentiellement une direction, des aegagropiles de P. oceanica de formes majoritairement ellipsoïdales s’échoueront le long des plages. [less ▲]

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See detailMeasuring porosity inside a cross-section of a tube
Plougonven, Erwan ULiege

Report (2018)

This macro (source code at the end of the document) was written to measure the porosity inside an axial crosssection in a tube. The macro makes four assumptions: 1. The cross-section is perpendicular to ... [more ▼]

This macro (source code at the end of the document) was written to measure the porosity inside an axial crosssection in a tube. The macro makes four assumptions: 1. The cross-section is perpendicular to the tube axis 2. The tube thickness is uniform 3. No artefacts except noise are present in the images (e.g. beam hardening) 4. The solid appears in light gray over a dark background From the set of cross-sections to analyze, the macro first thresholds the images, find the region inside the tube and computes the porosity in that region. [less ▲]

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See detailX-ray µCT: how soil pore space description can be altered by image processing
Smet, Sarah ULiege; Plougonven, Erwan ULiege; Léonard, Angélique ULiege et al

in Vadose Zone Journal (2018), 17(1),

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See detailMaternal embryonic leucine zipper kinase inhibitor OTSSP167 has preclinical activity on multiple myeloma bone disease.
Muller, Joséphine ULiege; Bolomsky, Arnold; Dubois, Sophie ULiege et al

in Haematologica (2018), 103

Multiple myeloma bone disease is characterized by an uncoupling of bone remodeling in the multiple myeloma microenvironment, resulting in the development of lytic bone lesions. Most myeloma patients ... [more ▼]

Multiple myeloma bone disease is characterized by an uncoupling of bone remodeling in the multiple myeloma microenvironment, resulting in the development of lytic bone lesions. Most myeloma patients suffer from these bone lesions, which not only causes morbidity but also negatively impacts survival. The development of novel therapies, ideally with a combined anti-resorptive and bone-anabolic effect, is of great interest because lesions persist with the current standard of care, even in patients in complete remission. We have previously shown that MELK plays a central role in proliferation-associated high-risk multiple myeloma and its inhibition with OTSSP167 resulted in decreased tumor load. MELK inhibition in bone cells has not yet been explored, although some reports suggest factors downstream of MELK stimulate osteoclast activity and inhibit osteoblast activity, which makes MELK inhibition a promising therapeutic approach. Therefore, we assessed the effect of OTSSP167 on bone cell activity and the development of myeloma-induced bone disease. OTSSP167 inhibited osteoclast activity in vitro by decreasing progenitor viability as well as via a direct anti-resorptive effect on mature osteoclasts. In addition, OTSSP167 stimulated matrix deposition and mineralization by osteoblasts in vitro. This combined anti-resorptive and osteoblast-stimulating effect of OTSSP167 resulted in the complete prevention of lytic lesions and bone loss in myeloma-bearing mice. Immunohistomorphometric analyses corroborated our in vitro findings. In conclusion, we show that OTSSP167 has a direct effect on myeloma-induced bone disease in addition to its anti-multiple myeloma effect, which warrants further clinical development of MELK inhibition in multiple myeloma. [less ▲]

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See detailComprehensive study of the drying behavior of Boom clay:Experimental investigation and numerical modeling
Hubert, Julien ULiege; Plougonven, Erwan ULiege; Prime, Noémie et al

in International Journal for Numerical and Analytical Methods in Geomechanics (2018)

This paper presents a thermo-hydro-mechanical framework to model the dryingbehavior of Boom clay. First, the experimental campaign conducted Noémie Primeis briefly presented because it is used to validate ... [more ▼]

This paper presents a thermo-hydro-mechanical framework to model the dryingbehavior of Boom clay. First, the experimental campaign conducted Noémie Primeis briefly presented because it is used to validate the model. The data acquisitionand processing is emphasized because of the use of X-ray microtomography to beable to more accurately compare experimental and numerical strain fields. The dif-ferent submodels are introduced. Numerical simulations are performed to illustratethe capability of the proposed model to reproduce the observed behavior. Finally,a comprehensive sensitivity study on several key model parameters associated withthe water retention curve, and the permeability of the medium, is performed to get abetter understanding of the physics behind the coupled model. [less ▲]

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See detailImprovement of bone allograft recolonization by adipose stem cells: impact of bone graft demineralization
Veriter, S; Palacios, P; Mauquoy, S et al

Conference (2017, December 03)

Bone allografts combined with mesenchymal stem cells are proposed for bone tissue engineering but remains limited by a low degree of stem cells spreading and cellular recolonization. We postulate to ... [more ▼]

Bone allografts combined with mesenchymal stem cells are proposed for bone tissue engineering but remains limited by a low degree of stem cells spreading and cellular recolonization. We postulate to demineralize bone allografts in view to improve adipose stem cells (ASCs) colonization and the bioactivity of the graft. Bone allografts (n=16) were treated for decellularization (4 groups of demineralization time: 0, 4, 8, 12 hours). The implants were compared in terms of residual calcium, mineral density and bioactivity (for BMP-2/VEGF contents). Each implant was scanned by microtomography to analyze macroporosity and open porosity. Helium pycnometry and Hg porosimetry were performed to assess the absolute density and microporosity. Bone surface analysis was assessed by X-Ray photoelectron spectroscopy and SEM. The bone graft recolonization by ASCs was studied in vitro by SEM, histology and DNA extraction at 24 hours/day 15 post-cellular seeding. Finally, ASCs combined with non-/demineralized bone matrix were implanted into the lumbar muscles of 10 nude rats (in comparison to bone grafts w/o cells) to study the osteoinductivity/angiogenicity by imagery/histology 29 days after implantation. A significant reduction of the calcium concentration (>-90%) was found in demineralized bone in comparison to native grafts as revealed by ionometry (0.27 vs. 4.1 g/L) and pQCT (0 vs. 0.39 g/ cm?). Demineralization significantly increase the macroporosity (>100μm by +13%) and the open porosity (>4 cm?/g vs. 2.1±1.0 cm?/g in comparison to the native graft,p<0.05). A significant increase of microporosity (>10 μm by +158% and <100 nm by 558%) was also found after demineralization. Helium pycnometry confirmed the correlation between the decrease of absolute density and demineralization of the bone graft (R?=0.81). A positive linear correlation between the decrease of calcium/increase of nitrogen atoms (at the bone surface) and the time of demineralization was found (R?=0.99,p<0.001). At day 15 post-incubation, a significant higher ASCs colonization of the bone graft was found for tissue demineralized during 12 hours (p<0.05). In conclusion, the demineralization of cancellous bones significantly improves the colonization by ASCs in view to return the bioactivity for bone regeneration. [less ▲]

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See detailBioactivity of a tissue-engineered product: bridging the gap between academic and clinical studies
Veriter, S; Palacios, P; Bidias, B et al

Conference (2017, December 02)

The translation of cell-based therapeutics from academic and fundamental sciences to clinical trial settings follows a preclinical pathway with rigorous regulatory oversights to ensure the cellmediated ... [more ▼]

The translation of cell-based therapeutics from academic and fundamental sciences to clinical trial settings follows a preclinical pathway with rigorous regulatory oversights to ensure the cellmediated therapeutic effect. Although international guidelines thoroughly describe single-dose toxicity and biodistribution studies, the quantitative evaluation of the biological activity remains a major challenge for biotechnology companies and authorities. Here we discuss a strategy to demonstrate the bioactivity of an osteogenic tissue-engineered product intended to promote angiogenesis and osteogenesis in a bone defect. Osteogenic 3-dimensional (3D) grafts were manufactured as a pharmaceutical batch. A sequence of chemical treatment was applied on the native graft in view to obtained a decellularized 3D-matrix as confirmed by a reduction of >90% and 40-80% of the cellular and growth factors (VEGF, IGF1) contents, respectively. Decellularized and native grafts were implanted intra-muscularly (after cauterization of the lumbar region, n=10 nude rats) to assess the mineralization (X-ray microCT and histomorphometry on Von Kossa staining) and angiogenesis (histomorphometry on Masson’s Trichrome and Von Willebrand Factor immunostaining) at day 29 postimplantation. Human cells detection (in the explanted tissue) were also quantified after KU80/HLA type I immunostaining at the implantation site. A significant higher mineralization was found for explanted samples from the native osteogenic 3D grafts in comparison to the decellularized tissues (Bone volume/tissue volume of 2.92 ± 1.12% vs. 0.38 ± 0.59%, respectively. [less ▲]

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