229 results on '"Gillain A"'
Search Results
2. Impact of Tether Length and Flexibility on the Efficiency of Analyte Capture by Tethered Receptors
- Author
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Beggiato, Matteo, primary, Payen, Hugo, additional, Dupont-Gillain, Christine, additional, and Krishnamoorthy, Sivashankar, additional
- Published
- 2023
- Full Text
- View/download PDF
3. Confined adsorption within nanopatterns as generic means to drive high adsorption efficiencies on affinity sensors
- Author
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Beggiato, Matteo, primary, Rastogi, Rishabh, additional, Dupont-Gillain, Christine, additional, and Krishnamoorthy, Sivashankar, additional
- Published
- 2022
- Full Text
- View/download PDF
4. Impact of tether length and flexibility on the efficiency of analyte capture by tethered receptors
- Author
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Matteo Beggiato, Hugo Payen, Christine Dupont-Gillain, and Sivashankar Krishnamoorthy
- Subjects
Computer Science (miscellaneous) ,Electrical and Electronic Engineering ,Instrumentation ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials - Published
- 2023
5. Evolution of cumulative live birth and dropout rates over six complete IVF/ICSI cycles: a large prospective cohort study
- Author
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Christine Wyns, Nicolas Gillain, Candice Autin, Kris Bogaerts, Frank Vandekerckhove, Christophe Blockeel, Anne Delbaere, Tom Coetsier, Diane De Neubourg, Elisabeth Anagnostou, UCL - SSS/IREC/GYNE - Pôle de Gynécologie, UCL - (SLuc) Service de gynécologie et d'andrologie, Surgical clinical sciences, Reproduction and Genetics, and Centre for Reproductive Medicine - Gynaecology
- Subjects
Change over time ,medicine.medical_specialty ,Patient Dropouts ,medicine.medical_treatment ,Dropout (communications) ,Drop-out rate ,Discontinuation ,Intracytoplasmic sperm injection ,medicine ,Humans ,Prospective Studies ,Sperm Injections, Intracytoplasmic ,Birth Rate ,Prospective cohort study ,Biology ,Cumulative live birth rate ,Assisted reproductive technology ,Cumulative multiple live birth rate ,Obstetrics ,business.industry ,IVF/ICSI ,Obstetrics and Gynecology ,Ivf icsi ,cumulative live birth rate ,cumulative multiple live birth rate ,Reproductive Medicine ,Female ,Human medicine ,Live birth ,business ,Developmental Biology - Abstract
RESEARCH QUESTION: How do cumulative live birth rates (CLBR), cumulative multiple live birth rates (CMLBR) and dropout rates over six IVF and intracytoplasmic sperm injection (ICSI) cycles change over time? DESIGN: Prospective longitudinal cohort (n = 16,073 patients; 48,946 cycles) starting a first fresh assisted reproductive technology cycle between 1 January 2014 and 31 December 2016, with follow-up until 31 December 2017. Outcomes between the periods 2014-2017 and 2009-2012 were compared. RESULTS: Conservative estimates of CLBR after six complete cycles were significantly higher in women younger than 35 years after every cycle: one to three, adjusted P-value [p adj] < 0.0001; four, p = 0.01; five, p adj = 0.03; six, p adj = 0.04) and after the first cycle in women aged 35-37 years (p adj = 0.04) in 2014-2017 versus 2009-2012. For an optimal estimate, the CLBR was significantly higher after the first three cycles in women younger than 35 years (all p adj < 0.0001) and after the first cycle in women aged 35-37 years (p adj = 0.04). The CMLBR rate decreased from 5.1% ± 0.19 (SE) to 4.1% ± 0.16 for the conservative estimate and from 8.6% ±0.37 (SE) to 6.7% ± 0.30 for the optimal estimate after six complete cycles for the whole cohort. Dropout rates of complete cycles were 26.5% 29.4%, 33.4%, 38.9% and 47.3% after the first to fifth cycle, respectively. Compared with 2009-2012, the dropout rate in the current period was significantly higher for the first (P < 0.0001) and second (P = 0.0124) cycle. CONCLUSION: Over six complete IVF/ICSI cycles, CLBR and dropout rates increased and multiple live birth rates decreased when 2014-2017 was compared with 2009-2012. ispartof: REPRODUCTIVE BIOMEDICINE ONLINE vol:42 issue:4 pages:717-724 ispartof: location:Netherlands status: published
- Published
- 2021
6. Effect of nanoconfinement on the enzymatic activity of bioactive layer-by-layer assemblies in nanopores
- Author
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UCL - SST/IMCN - Institute of Condensed Matter and Nanosciences, Kurylo, Ievgen, Demoustier-Champagne, Sophie, Dupont-Gillain, Christine C., UCL - SST/IMCN - Institute of Condensed Matter and Nanosciences, Kurylo, Ievgen, Demoustier-Champagne, Sophie, and Dupont-Gillain, Christine C.
- Abstract
In vivo, enzymatic reactions occur in confined environments. Such conditions can strongly improve enzyme behavior and are therefore interesting to study for further applications in biocatalysis. Here, we report on the influence of nanoconfinement on the catalytic properties of enzyme-based nanotubes, built by the layer-by-layer (LbL) assembly of branched polyethylenimine (bPEI) and glucose oxidase (GOx) in nanoporous polycarbonate membranes (PCm). More precisely, the influence of nanoconfinement on the biocatalytic activity is investigated by varying the number of (bPEI/GOx) bilayers, the concentration of polyelectrolytes (PEs) used for LbL deposition and the pore diameter of the PC membrane. Bicinchoninic acid (BCA) assay is employed to estimate the amount of enzyme loaded in the different LbL assemblies. The enzymatic activity was monitored, and found to depend on the three studied parameters. Typically, it decreases with decreasing pore diameter under high concentration of PEs, which may be attributed to limitations of substrate/product diffusion within the network formed in small pores. However, when lower concentration of PEs is used for the LbL assembly, the assemblies features a different macromolecular distribution and the enzymatic activity becomes optimal for low pore diameters. The results of this study pave the way to a more rational design of enzyme-loaded porous nanostructures for biocatalysis.
- Published
- 2022
7. Confined adsorption within nanopatterns as generic means to drive high adsorption efficiencies on affinity sensors
- Author
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UCL - SST/IMCN - Institute of Condensed Matter and Nanosciences, Beggiato, Matteo, Rastogi, Rishabh, Dupont-Gillain, Christine C., Krishnamoorthy, Sivashankar, UCL - SST/IMCN - Institute of Condensed Matter and Nanosciences, Beggiato, Matteo, Rastogi, Rishabh, Dupont-Gillain, Christine C., and Krishnamoorthy, Sivashankar
- Abstract
Miniaturization of the sensor active areas to length scales of the order of the analyte has been sought as means to reduce device footprints, and to capitalize on the novel optical and electronic enhancements that arise at this scale. However, little is known on what to expect of the sensor behaviour if the sensor footprints are shrunk to the dimensions of the order of analyte themselves. Our results demonstrate the densities and kinetics of adsorption of analyte to significantly increase with decrease in the sensor footprints to dimensions of the order of few multiples of analyte dimensions. Such increase is found to be generic, irrespective of the nature of interactions that drive adsorption, exhibiting qualitative similarity for electrostatic adsorption of nanoparticles, chemisorption of primary oligonucleotides, or complementary base pairing with target nucleotides. The carryover of these benefits onto a macroscopic sensor however requires high density nanopatterns exhibiting significant fill factors withtout compromising inter-feature isolation. The impact of feature dimensions, pattern fill factors, analyte concentrations, presence of convective flow, or the density of receptors are investigated using quantitative and real-time measurements of the nanostructure-analyte interactions using nanopatterned QCM sensors. The results indicate significant opportunities for rational design of nanopatterned macroscopic sensors, as well as nanoscopic sensors with sensor active areas of the order of analyte dimensions, e.g., electromagnetic hot-spots, or nanowire sensors.
- Published
- 2022
8. Effect of nanoconfinement on the enzymatic activity of bioactive Layer-by-Layer assemblies in nanopores
- Author
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Kurylo, Ievgen, primary, Demoustier-Champagne, Sophie, additional, and Dupont-Gillain, Christine, additional
- Published
- 2022
- Full Text
- View/download PDF
9. SARS-CoV-2 Seroprevalence Among Health Care Workers After the First and Second Pandemic Wave
- Author
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Nathalie de Visscher, Xavier Holemans, Aline Gillain, Anne Kornreich, Raphael Lagasse, Philippe Piette, Manfredi Ventura, Frédéric Thys, and Frederic Carl Thys
- Published
- 2022
10. Confined Adsorption within Nanopatterns as Generic Means to Drive High Adsorption Efficiencies on Affinity Sensors
- Author
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Matteo Beggiato, Rishabh Rastogi, Christine Dupont-Gillain, Sivashankar Krishnamoorthy, and UCL - SST/IMCN - Institute of Condensed Matter and Nanosciences
- Subjects
History ,Polymers and Plastics ,Metals and Alloys ,Condensed Matter Physics ,Industrial and Manufacturing Engineering ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Surfaces ,Coatings and Films ,Materials Chemistry ,Electronic ,Optical and Magnetic Materials ,Electrical and Electronic Engineering ,Business and International Management ,Instrumentation - Abstract
Miniaturization of the sensor active areas to length scales of the order of the analyte has been sought as means to reduce device footprints, and to capitalize on the novel optical and electronic enhancements that arise at this scale. However, little is known on what to expect of the sensor behaviour if the sensor footprints are shrunk to the dimensions of the order of analyte themselves. Our results demonstrate the densities and kinetics of adsorption of analyte to significantly increase with decrease in the sensor footprints to dimensions of the order of few multiples of analyte dimensions. Such increase is found to be generic, irrespective of the nature of interactions that drive adsorption, exhibiting qualitative similarity for electrostatic adsorption of nanoparticles, chemisorption of primary oligonucleotides, or complementary base pairing with target nucleotides. The carryover of these benefits onto a macroscopic sensor however requires high density nanopatterns exhibiting significant fill factors withtout compromising inter-feature isolation. The impact of feature dimensions, pattern fill factors, analyte concentrations, presence of convective flow, or the density of receptors are investigated using quantitative and real-time measurements of the nanostructure-analyte interactions using nanopatterned QCM sensors. The results indicate significant opportunities for rational design of nanopatterned macroscopic sensors, as well as nanoscopic sensors with sensor active areas of the order of analyte dimensions, e.g., electromagnetic hot-spots, or nanowire sensors.
- Published
- 2022
11. SARS-CoV-2 Seroprevalence Among Health Care Workers After the First and Second Pandemic Wave
- Author
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de Visscher, Nathalie, primary, Holemans, Xavier, additional, Gillain, Aline, additional, Kornreich, Anne, additional, Lagasse, Raphael, additional, Piette, Philippe, additional, Ventura, Manfredi, additional, Thys, Frédéric, additional, and Thys, Frederic Carl, additional
- Published
- 2022
- Full Text
- View/download PDF
12. Reprise de greffe du LCA, par reconstruction combinée et anatomique du LCA par autogreffe de TQ et du LAL par allogreffe de DI, avec tunnel unique au fémur : résultats cliniques d’une série de 58 cas avec un recul minimum de 2 ans
- Author
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Gillain, Laurent, primary, Blanchard, Jacques, additional, Gardon, Roland, additional, Billières, Julien, additional, and Siegrist, Olivier, additional
- Published
- 2021
- Full Text
- View/download PDF
13. Dietary Macronutrient Composition in Relation to Circulating HDL and Non-HDL Cholesterol: A Federated Individual-Level Analysis of Cross-Sectional Data from Adolescents and Adults in 8 European Studies
- Author
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Pinart, Mariona, primary, Jeran, Stephanie, additional, Boeing, Heiner, additional, Stelmach-Mardas, Marta, additional, Standl, Marie, additional, Schulz, Holger, additional, Harris, Carla, additional, von Berg, Andrea, additional, Herberth, Gunda, additional, Koletzko, Sybille, additional, Linseisen, Jakob, additional, Breuninger, Taylor A, additional, Nöthlings, Ute, additional, Barbaresko, Janett, additional, Benda, Stefan, additional, Lachat, Carl, additional, Yang, Chen, additional, Gasparini, Paolo, additional, Robino, Antonietta, additional, Rojo-Martínez, Gemma, additional, Castaño, Luís, additional, Guillaume, Michèle, additional, Donneau, Anne-Françoise, additional, Hoge, Axelle, additional, Gillain, Nicolas, additional, Avraam, Demetris, additional, Burton, Paul R, additional, Bouwman, Jildau, additional, Pischon, Tobias, additional, and Nimptsch, Katharina, additional
- Published
- 2021
- Full Text
- View/download PDF
14. Reprise de greffe du LCA, par reconstruction combinée et anatomique du LCA par autogreffe de TQ et du LAL par allogreffe de DI, avec tunnel unique au fémur : résultats cliniques d’une série de 58 cas avec un recul minimum de 2 ans
- Author
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Olivier Siegrist, Jacques Blanchard, Julien Billières, Laurent Gillain, and Roland Gardon
- Subjects
Orthopedics and Sports Medicine ,Surgery - Published
- 2021
15. Antimicrobial peptide encapsulation and sustained release from polymer network particles prepared in supercritical carbon dioxide
- Author
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Rahmet Parilti, Christine C. Dupont-Gillain, Michaël Alexandre, Jérémie Caprasse, Christine Jérôme, Raphaël Riva, Carine Bebrone, Steven M. Howdle, and Hélène Vandegaart
- Subjects
Staphylococcus aureus ,Surface Properties ,Peptide ,Microbial Sensitivity Tests ,02 engineering and technology ,Bradykinin ,010402 general chemistry ,Methacrylate ,01 natural sciences ,Polymerization ,Biomaterials ,Colloid and Surface Chemistry ,Drug Resistance, Bacterial ,Humans ,Particle Size ,Polyhydroxyethyl Methacrylate ,chemistry.chemical_classification ,Dispersion polymerization ,Drug Carriers ,Supercritical carbon dioxide ,Polymer network ,technology, industry, and agriculture ,Polymer ,Carbon Dioxide ,021001 nanoscience & nanotechnology ,Antimicrobial ,Anti-Bacterial Agents ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Drug Liberation ,Cross-Linking Reagents ,chemistry ,Chemical engineering ,Nanoparticles ,Peptides ,0210 nano-technology ,Antimicrobial Cationic Peptides - Abstract
Antimicrobial peptide loaded poly(2-hydroxyethyl methacrylate) particles were synthesized in supercritical carbon dioxide via one-pot free-radical dispersion polymerisation of 2-hydroxyethyl methacrylate and a cross-linker. Discrete particles with a well-defined spherical morphology and a diameter as low as 450 nm have been obtained in mild conditions. The encapsulation and release of the peptide were confirmed by antimicrobial tests that demonstrated for the first time a sustained release of the peptide from poly(2-hydroxyethyl methacrylate) microgels prepared by one-pot dispersion polymerization in supercritical carbon dioxide and then dispersed in water.
- Published
- 2018
16. An Assessment of the Toulouse Saint Louis University Mini Falls Assessment Tool to Predict Incident Falls among Older Adults Residing in Nursing Homes: A 6-Month Prospective Study
- Author
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Locquet, M., primary, Bonnard, F., additional, Beaudart, C., additional, Coendo, C., additional, Gillain, S., additional, Reginster, J.-Y., additional, and Bruyère, Olivier, additional
- Published
- 2021
- Full Text
- View/download PDF
17. Challenges in treating physician burnout: The psychologist's perspective
- Author
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Lenoir, Anne-Laure, primary, De Troyer, Caroline, additional, Demoulin, Carole, additional, Gillain, Ingrid, additional, and Bayot, Marie, additional
- Published
- 2021
- Full Text
- View/download PDF
18. Evolution of cumulative live birth and dropout rates over six complete IVF/ICSI cycles: a large prospective cohort study
- Author
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De Neubourg, Diane, primary, Bogaerts, Kris, additional, Anagnostou, Elisabeth, additional, Autin, Candice, additional, Blockeel, Christophe, additional, Coetsier, Tom, additional, Delbaere, Anne, additional, Gillain, Nicolas, additional, Vandekerckhove, Frank, additional, and Wyns, Christine, additional
- Published
- 2021
- Full Text
- View/download PDF
19. Protein-based polyelectrolyte multilayers
- Author
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Damien Lefèvre, Sophie Demoustier-Champagne, Christine C. Dupont-Gillain, Aurélien vander Straeten, and UCL - SST/IMCN - Institute of Condensed Matter and Nanosciences
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Materials science ,Layer by layer ,Temperature ,Proteins ,Nanotechnology ,02 engineering and technology ,Surfaces and Interfaces ,Hydrogen-Ion Concentration ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Polyelectrolytes ,Polyelectrolyte ,0104 chemical sciences ,Solutions ,Adsorption ,Colloid and Surface Chemistry ,Drug delivery ,Physical and Theoretical Chemistry ,0210 nano-technology ,Biosensor ,Charged species ,Macromolecule - Abstract
The immobilization of proteins to impart specific functions to surfaces is topical for chemical engineering, healthcare and diagnosis. Layer-by-Layer (LbL) self-assembly is one of the most used method to immobilize macromolecules on surfaces. It consists in the alternate adsorption of oppositely charged species, resulting in the formation of a multilayer. This method in principle allows any charged object to be immobilized on any surface, from aqueous solutions. However, when it comes to proteins, the promises of versatility, simplicity and universality that the LbL approach holds are unmet due to the heterogeneity of protein properties. In this review, the literature is analyzed to make a generic approach emerge, with a view to facilitate the LbL assembly of proteins with polyelectrolytes (PEs). In particular, this review aims at guiding the choice of the PE and the building conditions that lead to the successful growth of protein-based multilayered self-assemblies.
- Published
- 2020
20. Use of a quartz crystal microbalance platform to study protein adsorption on aluminum hydroxide vaccine adjuvants: Focus on phosphate-hydroxide ligand exchanges
- Author
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Christine C. Dupont-Gillain, Jean-François Art, Patrice Soumillion, and UCL - SST/IMCN/BSMA - Bio and soft matter
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Ovalbumin ,medicine.medical_treatment ,Chemistry, Pharmaceutical ,Drug Compounding ,aluminum hydroxide ajuvant ,Pharmaceutical Science ,Aluminum Hydroxide ,Serum Albumin, Human ,02 engineering and technology ,Ligands ,030226 pharmacology & pharmacy ,03 medical and health sciences ,chemistry.chemical_compound ,quartz crystal microbalance ,0302 clinical medicine ,Adsorption ,Adjuvants, Immunologic ,vaccine ,medicine ,Bovine serum albumin ,Vaccines ,biology ,Chemistry ,Osmolar Concentration ,Serum Albumin, Bovine ,Quartz crystal microbalance ,021001 nanoscience & nanotechnology ,Human serum albumin ,dephosphorylation ,antigen adsorption ,ligand exchange ,Ionic strength ,biology.protein ,Quartz Crystal Microbalance Techniques ,Hydroxide ,0210 nano-technology ,Adjuvant ,Nuclear chemistry ,medicine.drug ,Protein adsorption - Abstract
Aluminum hydroxide (AH) salts are widely used as vaccine adjuvants and controlling antigen-AH interactions is a key challenge in vaccine formulation. In a previous work, we have developed a quartz crystal microbalance (QCM) platform, based on stable AH-coated sensors, to explore the mechanisms of model antigen adsorption. The QCM study of bovine serum albumin (BSA) adsorption at different pH and ionic strength (I) values showed that protein adsorption on AH adjuvant at physiological pH cannot be explained mainly by electrostatic interactions, in contrast with previous reports. Here, we exploit further the developed QCM platform to investigate the role of phosphate-hydroxyl ligand exchanges in the adsorption mechanism of BSA, human serum albumin (HSA) and ovalbumin (OVA) on two commercial AH adjuvants. BSA adsorption decreased on immobilized AH particles previously treated with KH2PO4, highlighting the role of exchangeable sites on AH particles in the adsorption process. BSA and OVA were dephosphorylated by treatment with an acid phosphatase to decrease their phosphate content by about 80% and 25%, respectively. Compared to native BSA, adsorption of dephosphorylated BSA decreased significantly on one AH adjuvant at pH 7. Adsorption of dephosphorylated OVA was comparable to the one of native OVA. Further QCM assays showed that phospho-amino acids (PO4-serine and PO4-threonine) displaced previously adsorbed BSA and OVA from AH particles in conditions that were depending on the protein and the AH. Taken together, these observations suggest that phosphate-hydroxyl ligand exchange is an important adsorption mechanism of proteins on AH. These results moreover confirm that the developed AH-coated QCM sensors offer a new platform for the study of antigen adsorption, to the benefit of vaccine formulation.
- Published
- 2020
21. Unravelling surface changes on Cu-Ni alloy upon immersion in aqueous media simulating catalytic activity of aerobic biofilms
- Author
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UCL - SST/IMCN/BSMA - Bio and soft matter, Aissaoui, Nesrine, Liascukiene, Irma, Genet, Michel, Dupont-Gillain, Christine C., El Kirat, Karim, Richard, Caroline, Landoulsi, Jessem, UCL - SST/IMCN/BSMA - Bio and soft matter, Aissaoui, Nesrine, Liascukiene, Irma, Genet, Michel, Dupont-Gillain, Christine C., El Kirat, Karim, Richard, Caroline, and Landoulsi, Jessem
- Abstract
Cu-Ni alloys are extensively used in contact with natural waters and are impacted by microbial activities of biofilms. The mechanisms by which surface changes occur upon immersion remain not well understood. Herein, an aerobic microbial activity of natural biofilms is mimicked by the enzymatic generation of an oxidizing agent and an organic acid. Surface changes are probed through a detailed analysis of XPS spectra which allowed a distinction between compounds of organic and inorganic nature to be made. Results show that the surface is composed of copper oxides/hydroxides, presumably Cu2O and Cu(OH)2 and Ni hydroxides. The enzyme-catalyzed reaction causes a significant depletion of Ni and inorganic oxygen, while the concentration of copper, CuI and CuII, varies only slightly. Surface changes concern the organic phase; the amount of organic compounds strikingly increases in the presence of enzymes, and the XPS spectra reveal the accumulation of compounds with high oxidized carbon content, attributed to adsorbed gluconate. Correlations between spectral data suggest the formation of Cu-gluconate complex, probably through coordinative bonds between gluconates and CuII on the oxide layer. These findings are particularly important to properly evaluate the impact of microbial activities on the sustainability of Cu-Ni alloys upon natural exposures.
- Published
- 2020
22. Investigation of the tensile behavior of treated flax fibre bio-composites at ambient humidity
- Author
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Ignace Verpoest, Christine C. Dupont-Gillain, A.W. Van Vuure, and Dieter Perremans
- Subjects
Materials science ,General Engineering ,Stiffness ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Flax fibre ,0104 chemical sciences ,Specific strength ,Tensile behavior ,Flexural strength ,Compatibility (mechanics) ,Ultimate tensile strength ,Ceramics and Composites ,medicine ,Interphase ,Composite material ,medicine.symptom ,0210 nano-technology - Abstract
The high specific strength and stiffness and excellent damping behavior promote the use of flax fibre composites in the construction sector. However, the limited compatibility between raw flax fibres and bio-epoxy resin often leads to composites with mechanical properties well below their theoretical capacities. Moreover, the incomplete understanding of the intrinsic non-linear mechanical behavior of flax fibre composites forces the application of larger safety factors. In this study, three chemical treatments are applied to improve the interphase properties and gain further insight in the longitudinal tensile behavior of flax fibre bio-epoxy composites. Both alkali and APS treatment result in a threefold improvement in the transverse flexural strength to ∼30MPa. Both treatments additionally shift the weakest link to the elementary fibre interphase strength. Analysis of the longitudinal tensile stress-strain curves of UD flax fibre composites results in a tri-linear shape that is preserved after treatment.
- Published
- 2018
23. Inter-individual variability of social perception and social knowledge impairments among patients with schizophrenia
- Author
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Kitoko, Germain Manzekele Bin, primary, Maurage, Pierre, additional, ma Miezi, Samuel Mampunza, additional, Gillain, Benoit, additional, Kiswanga, Alain Pierre, additional, and Constant, Eric, additional
- Published
- 2020
- Full Text
- View/download PDF
24. Protein-based polyelectrolyte multilayers
- Author
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vander Straeten, Aurélien, primary, Lefèvre, Damien, additional, Demoustier-Champagne, Sophie, additional, and Dupont-Gillain, Christine, additional
- Published
- 2020
- Full Text
- View/download PDF
25. Unravelling surface changes on Cu-Ni alloy upon immersion in aqueous media simulating catalytic activity of aerobic biofilms
- Author
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Aissaoui, Nesrine, primary, Liascukiene, Irma, additional, Genet, Michel J., additional, Dupont-Gillain, Christine, additional, El Kirat, Karim, additional, Richard, Caroline, additional, and Landoulsi, Jessem, additional
- Published
- 2020
- Full Text
- View/download PDF
26. Use of a quartz crystal microbalance platform to study protein adsorption on aluminum hydroxide vaccine adjuvants: Focus on phosphate-hydroxide ligand exchanges
- Author
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Art, Jean-François, primary, Soumillion, Patrice, additional, and Dupont-Gillain, Christine C., additional
- Published
- 2020
- Full Text
- View/download PDF
27. “Patient participation” and related concepts: A scoping review on their dimensional composition
- Author
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Halabi, I. Ortiz, primary, Scholtes, B., additional, Voz, B., additional, Gillain, N., additional, Durieux, N., additional, Odero, A., additional, Baumann, M., additional, Ziegler, O., additional, Gagnayre, R., additional, Guillaume, M., additional, Bragard, I., additional, and Pétré, B., additional
- Published
- 2020
- Full Text
- View/download PDF
28. Using supervised learning machine algorithm to identify future fallers based on gait patterns: A two-year longitudinal study
- Author
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Gillain, Sophie, primary, Boutaayamou, Mohamed, additional, Schwartz, Cedric, additional, Brüls, Olivier, additional, Bruyère, Olivier, additional, Croisier, Jean-Louis, additional, Salmon, Eric, additional, Reginster, Jean-Yves, additional, Garraux, Gaëtan, additional, and Petermans, Jean, additional
- Published
- 2019
- Full Text
- View/download PDF
29. Challenges in treating physician burnout: The psychologist's perspective
- Author
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Ingrid Gillain, Marie Bayot, Anne-Laure Lenoir, Carole Demoulin, and Caroline De Troyer
- Subjects
Physician burnout ,Nursing ,Feeling ,media_common.quotation_subject ,education ,Perspective (graphical) ,Psychological intervention ,Identity (social science) ,Workload ,Thematic analysis ,Burnout ,Psychology ,media_common - Abstract
Objective Burnout is a multidimensional stress syndrome that is particularly prevalent in physician populations. While the literature expands on preventive and curative interventions, relatively little is known about factors that may hamper their success. The aim of this study was (1) to identify the specific challenges to treat physician burnout and (2) to explore the origins of these challenges. Methods We conducted semi-structured interviews with twelve psychologists who had treated physicians with burnout and performed thematic analysis of data. Results Psychologists identified two specific challenges in treating physician burnout. First, physicians were reluctant to seek help from health professionals and tended to so at more severe stages of exhaustion. Second, physicians were feeling uncomfortable in the role of patient, and many of them had difficulties to accept treatment. Psychologists suggested the following causes of these challenges: (1) most physicians did not have a general practitioner, (2) they felt guilty about reducing their workload, and (3) tended to confuse professional and personal engagement. According to participants, medical education, the professional culture and the image of the profession in the wider community were likely factors contributing to physicians’ reluctance to seek and accept care. Discussion This research showed that the specific challenges to treat physician burnout are mostly related to their reluctance to ask for help and to put their trust in other caregivers. Among the reasons for this behavior, most are linked with physician's representation of professional identity as enduring and selfless. Conclusion Further studies are needed to explore how medical education and professional culture can be changed to reduce the risk of physician burnout and facilitate care when it nonetheless arises.
- Published
- 2021
30. Combination of collagen and fibronectin to design biomimetic interfaces: Do these proteins form layer-by-layer assemblies?
- Author
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Sara Mauquoy and Christine C. Dupont-Gillain
- Subjects
Surface Properties ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Immunoenzyme Techniques ,Contact angle ,Colloid and Surface Chemistry ,Adsorption ,Biomimetics ,Materials Testing ,Animals ,Physical and Theoretical Chemistry ,Chemistry ,Cell Membrane ,Layer by layer ,Surfaces and Interfaces ,General Medicine ,Quartz crystal microbalance ,Quartz Crystal Microbalance Techniques ,021001 nanoscience & nanotechnology ,Polyelectrolyte ,Extracellular Matrix ,Fibronectins ,0104 chemical sciences ,Chemical engineering ,Surface modification ,Cattle ,Collagen ,0210 nano-technology ,Layer (electronics) ,Biotechnology - Abstract
Layer-by-layer (LbL) assembly is a surface modification method which may bring complexity to biointerfaces designed to control cell-material interactions. This work aims at investigating the LbL assembly of two extracellular matrix proteins, collagen (Col) and fibronectin (Fn), on polystyrene substrates. LbL assembly, which is widely applied to polyelectrolytes, is not easily transferred to proteins. Different buffers and conditions are tested, and LbL assembly is compared to the simultaneous adsorption of Fn and Col. Build-up and properties of the films are monitored using quartz crystal microbalance, ellipsometry, water contact angle measurements, and atomic force microscopy. Results show that denatured Col leads to smoother films, and that the addition of a polyethyleneimine anchoring layer increases film thickness. A more regular construction and thicker films are obtained with Hepes (pH 7.4) compared to other buffers. However, the LbL assembly is not sustainable and stops after the deposition of a few layers. Films obtained by simultaneous adsorption have lower water contact angles, different morphologies, lower water content and are as thick or thicker compared to the ones prepared by the LbL method. The present work shows that collagen and fibronectin are not involved in a true LbL assembly process. The obtained biointerfaces however exhibit different properties compared to those obtained by the one-step adsorption of these proteins. These differences could be exploited to control cell fate.
- Published
- 2016
31. Oxidation of laccase for improved cathode biofuel cell performances
- Author
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Christine C. Dupont-Gillain, Sophie Griveau, Michel J. Genet, Meihui Zheng, Claude Jolivalt, Laboratoire Charles Friedel, Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL), Institut de la matière condensée et des nanosciences / Institute of Condensed Matter and Nanosciences (IMCN), Université Catholique de Louvain = Catholic University of Louvain (UCL), Laboratoire de Réactivité de Surface (LRS), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Models, Molecular ,Bioelectric Energy Sources ,Protein Conformation ,Inorganic chemistry ,Biophysics ,7. Clean energy ,biocatalytic dioxygen reduction ,Electron Transport ,chemistry.chemical_compound ,Electron transfer ,Adsorption ,XPS ,Electrochemistry ,[CHIM]Chemical Sciences ,Peptide bond ,direct electron transfer ,[SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM] ,Physical and Theoretical Chemistry ,Electrodes ,Trametes ,chemistry.chemical_classification ,Laccase ,Schiff base ,Substrate (chemistry) ,oxidized laccase ,Glycosidic bond ,General Medicine ,Enzymes, Immobilized ,Carbon ,biocathode ,Oxygen ,chemistry ,biofuel cell ,Covalent bond ,diazonium salt ,Biocatalysis - Abstract
Graphite rods were modified by substituted aryldiazonium salts allowing subsequent laccase immobilisation and direct electron transfer at the cathode. Two covalent enzyme immobilisation methods were performed with carboxy and amino substituted grafted groups, either via the formation of an amide bond or a Schiff base between the glycosidic groups of the enzyme and the amino groups on the electrode surface, respectively. Laccase adsorption efficiency was consistently compared to the covalent attachment method on the same carbon surface, showing that the latter method led to a higher immobilisation yield when the electrode surface was functionalised with carboxylic groups, as shown from both laccase activity measurement towards an organic reducing substrate, ABTS, and quantitative XPS analysis. Both analytical methods led to similar laccase surface coverage estimations. From activity measurements, when laccase was covalently immobilised on the electrode functionalised with carboxylic groups, the surface coverage was found to be 43 ± 2% whereas it was only 10 ± 3% when laccase was adsorbed. Biocatalysed dioxygen reduction current was also higher in the case of covalent immobilisation. For the first time, oxidised laccase performances were compared to unmodified laccase, showing significant improved efficiency when using oxidised laccase: the current obtained with oxidised laccase was 141 ± 37 μA cm− 2 compared to 28 ± 6 μA cm− 2 for unmodified laccase after covalent immobilisation of the enzyme on a graphite electrode functionalised with carboxylic groups.
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- 2015
32. Minimal amounts of dipalmitoylphosphatidylcholine improve aerosol performance of spray-dried temocillin powders for inhalation
- Author
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Abdoul Aziz Sanogo, Rita Vanbever, Pierre Eloy, Brieuc Cuvelier, Christine C. Dupont-Gillain, Cristina Loira-Pastoriza, and Bernard Ucakar
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1,2-Dipalmitoylphosphatidylcholine ,Pharmaceutical Science ,Excipient ,Penicillins ,Mice ,chemistry.chemical_compound ,Administration, Inhalation ,medicine ,Animals ,Temocillin ,Particle Size ,Solubility ,Lung ,Aerosols ,Chromatography ,Inhalation ,Inhaler ,Dry Powder Inhalers ,chemistry ,Dipalmitoylphosphatidylcholine ,Particle ,Female ,Particle size ,Powders ,Crystallization ,medicine.drug - Abstract
Administration of antibiotics by inhalation can greatly improve drug targeting to the site of respiratory infections. In addition, dry powder inhalers are particularly convenient for the patients. The purposes of this study were to demonstrate the interest of pulmonary temocillin delivery to reach high temocillin concentrations locally in the lungs as well as to prepare a spray-dried temocillin powder for inhalation using a minimal amount of generally recognized as safe excipients. Intratracheal instillation of a temocillin solution allowed to reach higher and more sustained drug concentrations in the lungs than intravenous injection in mice, although a 10-fold lower temocillin dose was delivered intratracheally than systemically. A spray-dried powder of pure temocillin presented a fine particle fraction of 9% of the dose loaded in the inhaler. However, the incorporation of 0.5% to 20% of dipalmitoylphosphatidylcholine (DPPC) in the powder increased the fine particle fraction 4- to 5-fold. X-ray photoelectron spectroscopy and X-ray diffraction revealed that DPPC concentrated at the particle surface with its aliphatic chains laterally packed. The minimal amount of DPPC needed to improve the aerosol performance of temocillin supports the use of this excipient in the formulation of cohesive antibiotic powders for inhalation.
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- 2015
33. Using supervised learning machine algorithm to identify future fallers based on gait patterns: A two-year longitudinal study
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Olivier Bruyère, Jean-Louis Croisier, Mohamed Boutaayamou, Jean-Yves Reginster, Sophie Gillain, Gaëtan Garraux, Olivier Bruls, Jean Petermans, Cédric Schwartz, and Eric Salmon
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Male ,0301 basic medicine ,Aging ,Longitudinal study ,Computer science ,Pilot Projects ,Walking ,Individual risk ,Risk Assessment ,Biochemistry ,03 medical and health sciences ,0302 clinical medicine ,Endocrinology ,C4.5 algorithm ,Genetics ,Dual task walking ,Humans ,Longitudinal Studies ,Gait ,Postural Balance ,Molecular Biology ,Aged ,Aged, 80 and over ,Decision tree learning ,Supervised learning ,Cell Biology ,Data set ,030104 developmental biology ,Accidental Falls ,Female ,Independent Living ,Supervised Machine Learning ,Algorithm ,Algorithms ,030217 neurology & neurosurgery - Abstract
Introduction Given their major health consequences in the elderly, identifying people at risk of fall is a major challenge faced by clinicians. A lot of studies have confirmed the relationships between gait parameters and falls incidence. However, accurate tools to predict individual risk among independent older adults without a history of falls are lacking. Objective This study aimed to apply a supervised learning algorithm to a data set recorded in a two-year longitudinal study, in order to build a classification tree that could discern subsequent fallers based on their gait patterns. Methods A total of 105 adults aged >65 years, living independently at home and without a recent fall history were included in a two-year longitudinal study. All underwent physical and functional assessment. Gait speed, stride length, frequency, symmetry and regularity, and minimum toe clearance were recorded in comfortable, fast and dual task walking conditions in a standardized laboratory environment. Fall events were recorded using personal falls diaries. A supervised machine learning algorithm (J48) has been applied to the data recorded at inclusion in order to obtain a classification tree able to identify future fallers. Results Based on fall information from 96 volunteers, a classification tree correctly identifying 80% of future fallers based on gait patterns, gender, and stiffness, was obtained, with accuracy of 84%, sensitivity of 80%, specificity of 87%, a positive predictive value of 78%, and a negative predictive value of 88%. Discussion While the performances of the classification tree warrant further confirmation, it is the first predictive tool based on gait parameters that are identified (not clustered) allowing its use by other research teams. Conclusion This original longitudinal pilot study using a supervised machine learning algorithm, shows that gait parameters and clinical data can be used to identify future fallers among independent older adults.
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- 2019
34. Predicting the adhesion strength of thermoplastic/glass interfaces from wetting measurements
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Yichuan Zhang, C.A. Fuentes, Clemens Dransfeld, David Seveno, Christine C. Dupont-Gillain, H. Guo, Kunal Masania, J. De Coninck, A.W. Van Vuure, Wilhelm Woigk, and UCL - SST/IMCN - Institute of Condensed Matter and Nanosciences
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chemistry.chemical_classification ,Polypropylene ,Thermoplastic ,Materials science ,Maleic anhydride ,02 engineering and technology ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Polyvinylidene fluoride ,Surface energy ,0104 chemical sciences ,Contact angle ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,chemistry ,Wetting ,Composite material ,0210 nano-technology - Abstract
To evaluate compatibility between a substrate and a thermoplastic polymer, the established methodology is to estimate their surface composition in terms of surface energy components, utilizing the results of contact angle measurements of probe liquids onto substrate and polymer surfaces at room temperature. Using this methodology, polymer surfaces are studied in solid state, however, during spreading of polymers on a substrate, polymers are in molten state and at high temperature, having different surface energies and more complex polymer/substrate interactions due to polymer chain mobility. This paper presents a model study with practical relevance to predict polymer/substrate compatibility including contact angle measurements at high temperature directly performed between molten thermoplastics; polypropylene (PP), polyvinylidene fluoride (PVDF) and maleic anhydride-grafted polypropylene (MAPP), on smooth glass fibres and plates. The values of total surface energy of thermoplastics at high temperature (260 °C) are down to 57% of that measured at room temperature, which has a strong influence on the wetting prediction. Surface energies of both the polymer and the substrate were found not to be the only factor controlling the wetting behaviour of molten polymers and the level of adhesion with the substrate, but also some intrinsic characteristics of the polymer melt play a role. We also observed that the wetting behaviour of molten MAPP is affected by the maleic anhydride (MA) content, demonstrating dramatically different results to room temperature measurements, which is suspected to be due to the formation of covalent bonds of MA groups with the glass surface enhancing the interface strength beyond the shear strength of MAPP.
- Published
- 2018
35. Combined Anatomic Anterior Cruciate and Anterolateral Ligament Reconstruction With Quadriceps Tendon Autograft and Gracilis Allograft Through a Single Femoral Tunnel
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Ouabo, Eric Choudja, primary, Gillain, Laurent, additional, Saithna, Adnan, additional, Blanchard, Jacques, additional, Siegrist, Olivier, additional, and Sonnery-Cottet, Bertrand, additional
- Published
- 2019
- Full Text
- View/download PDF
36. Do patients from the Democratic Republic of Congo with schizophrenia have facial emotion recognition deficits?
- Author
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Kitoko, Germain Manzekele Bin, primary, Maurage, Pierre, additional, Peyroux, Elodie, additional, ma Miezi, Samuel Mampunza, additional, Gillain, Benoit, additional, and Constant, Eric, additional
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- 2019
- Full Text
- View/download PDF
37. Antimicrobial peptide encapsulation and sustained release from polymer network particles prepared in supercritical carbon dioxide
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Parilti, Rahmet, primary, Caprasse, Jérémie, additional, Riva, Raphaël, additional, Alexandre, Michaël, additional, Vandegaart, Hélène, additional, Bebrone, Carine, additional, Dupont-Gillain, Christine, additional, Howdle, Steven M., additional, and Jérôme, Christine, additional
- Published
- 2018
- Full Text
- View/download PDF
38. Reconstruction anatomique du ligament croisé antérieur et du ligament antérolatéral, par autogreffe de tendon du quadriceps et allogreffe de gracilis, avec un seul tunnel fémoral : technique
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Choudja Ouabo, Éric, primary, Gillain, Laurent, additional, Saithna, Adnan, additional, Blanchard, Jacques, additional, Siegrist, Olivier, additional, and Sonnery-Cottet, Bertrand, additional
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- 2018
- Full Text
- View/download PDF
39. Predicting the adhesion strength of thermoplastic/glass interfaces from wetting measurements
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Fuentes, C.A., primary, Zhang, Y., additional, Guo, H., additional, Woigk, W., additional, Masania, K., additional, Dransfeld, C., additional, De Coninck, J., additional, Dupont-Gillain, C., additional, Seveno, D., additional, and Van Vuure, A.W., additional
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- 2018
- Full Text
- View/download PDF
40. Influence of substrate nature and β-lactoglobulin on cleanability after soiling by suspension spraying and drying
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Marianne Sindic, Christine C. Dupont-Gillain, Paul Rouxhet, Yetioman Toure, and André Matagne
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Materials science ,Capillary action ,Applied Mathematics ,General Chemical Engineering ,Environmental engineering ,General Chemistry ,Industrial and Manufacturing Engineering ,Suspension (chemistry) ,Contact angle ,Surface tension ,Adsorption ,Chemical engineering ,Coagulation (water treatment) ,Layer (electronics) ,Protein adsorption - Abstract
Glass and stainless steel (StSteel, AISI304-2R), previously cleaned with ethanol (-Eth) or with ethanol and UV–Ozone treatment (-UVO), were soiled with quartz suspensions in water and in a β-lactoglobulin (β-LGB) solution, and dried. The cleanability (ease of quartz particle detachment) in water was evaluated using a radial-flow cell. The soiling suspension containing β-LGB was used as such or after heating for 4 h at 75 °C, which provoked coagulation of about 75% of β-LGB. The substrate–solution interfaces were characterized by X-ray photoelectron spectroscopy (XPS) analysis of conditioned substrates and by contact angle measurements. The substrate surfaces are covered by a layer of organic contaminants which are not removed by pre-cleaning or are adsorbed from the surroundings. The presence of β-LGB in the soiling suspension leads to protein adsorption, but a significant amount of contaminants remains at the surface. For three of the substrates tested (Glass-Eth, Glass-UVO, StSteel-UVO) the increase of cleanability when the soiling suspension contained β-LGB may be explained by lower capillary forces acting upon drying. Capillary forces are proportional to the liquid surface tension and depend in a less important way on substrate contact angle. However the order of cleanability observed for the substrates soiled with a suspension of quartz particles in water (Glass-Eth≅Glass-UVO
- Published
- 2015
41. Quality of life and physical components linked to sarcopenia: The SarcoPhAge study
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Médéa Locquet, Sophie Gillain, Jean-Yves Reginster, Olivier Bruyère, Justine Slomian, Jean Petermans, Charlotte Beaudart, A Quabron, and Fanny Buckinx
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Male ,Gerontology ,Sarcopenia ,Aging ,Longitudinal study ,Waist ,Activities of daily living ,Timed Up and Go test ,Risk Assessment ,Biochemistry ,Body Mass Index ,Absorptiometry, Photon ,Endocrinology ,Belgium ,Quality of life ,Activities of Daily Living ,Prevalence ,Genetics ,Humans ,Medicine ,Mass index ,Longitudinal Studies ,Geriatric Assessment ,Molecular Biology ,Aged ,Aged, 80 and over ,Hand Strength ,business.industry ,Cell Biology ,medicine.disease ,Quality of Life ,Lean body mass ,Accidental Falls ,Female ,business ,Algorithms - Abstract
Introduction The SarcoPhAge project is an ongoing longitudinal study following community-dwelling elderly subjects with the objective to assess some health and functional consequences of sarcopenia. The sarcopenia diagnosis algorithm developed by the European Working Group on Sarcopenia in Older People (EWGSOP) and used in the present study needs further validation through cross-sectional and longitudinal studies. The aim of the present study is to assess, using this algorithm, the prevalence of sarcopenia and the clinical components linked to this geriatric syndrome. Methods Participants were community dwelling subjects aged 65 years or older. To diagnose sarcopenia, we applied the definition of the EWGSOP. Muscle mass was measured by dual-energy X-ray absorptiometry, muscle strength by a hydraulic dynamometer and physical performance by the SPPB test. Large amounts of socio-demographic, anamnestic and clinical data were collected in all subjects. Results over one year 534 subjects were recruited for this study (60.5% of women, mean age of 73.5 ± 6.16 years), among whom 73 subjects were diagnosed sarcopenic, which represents a global prevalence of 13.7%. Prevalence was 11.8% in men and 14.9% in women. Sarcopenic subjects were older; had a lower Body Mass Index, lower calf, waist, wrist and arm circumferences; presented more cognitive impairments (Mini-Mental State Examination), more comorbidities; were more often malnourished; and consumed more drugs. After adjustment for age, BMI, cognitive status, nutritional status, number of comorbidities and number of drugs, sarcopenic subjects had a worse physical health-related quality of life (SF-36) for the domain of physical functioning, were at higher risk of falls (Timed Up and Go test), were more frail (Fried), presented more often tiredness for the achievement of activities of daily living (Mobility-test), presented less fat mass and obviously less lean mass. Sarcopenic women were also more dependent for housekeeping and handling finances (Lawton scale) than non-sarcopenic ones. Conclusion Sarcopenia seems to be associated with many harmful clinical components making this geriatric syndrome a real public health burden. Follow-up data of the SarcoPhAge study will be helpful to assess the outcomes of sarcopenia based on the EWGSOP diagnosis algorithm and its different proposed cut-offs.
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- 2015
42. In situ quartz crystal microbalance monitoring of the adsorption of polyoxometalate on a polyampholyte polymer matrix
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Colas Swalus, Michel Devillers, Marie Delcroix, Christine C. Dupont-Gillain, Gijo Raj, and Eric M. Gaigneaux
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chemistry.chemical_classification ,Supramolecular chemistry ,Nanotechnology ,Polymer ,Quartz crystal microbalance ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Catalysis ,Biomaterials ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Adsorption ,chemistry ,Chemical engineering ,Desorption ,Polyoxometalate ,Phosphotungstic acid - Abstract
Hybridization of polyoxometalates (POMs) via an organic-inorganic association constitutes a new route to develop heterogeneous POM catalysts with tunable supramolecular architecture. As the structural stability of POMs is strongly influenced by the pH conditions, a quantitative understanding of the POMs-polymer association is important in practical applications. Herein, we use Quartz Crystal Microbalance (QCM) to systematically investigate the interactions of Keggin phosphotungstic acid POM with a polyampholyte polymer-coated QCM sensor as a function of pH. The mass of adsorbed POMs increases when pH decreases from 5.6 to 2, indicating that electrostatic forces play a major role in the formation of POM-polymer hybrids. This finding is complemented by AFM images that show an increase in the size of the hybrid entities from 5 to 12 nm as the pH decreases from 5.6 to 2. The POM adsorbed amount at a particular pH value reaches an equilibrium level with time. The hybrids further gain in adsorbed mass only when lowering the pH value of the POM solution. The hybrid structure formed above pH 2 shows resistance to leaching as indicated by the steady level of the adsorbed mass during a rinsing step with water. However, at pH 2, the rinsing step causes desorption of some weakly adsorbed POMs. It is shown that leached POMs can be re-adsorbed back into the polymer matrix during a second contact with a POM solution at pH 2. This adsorption-desorption cycles of POMs were successfully repeated. Our experiments shed light into the coexistence of tightly as well as loosely bound POMs in hybrid catalyst formed at pH 2. The loosely bound POMs can potentially act as homogeneous catalysts when desorbed. However, these leached POMs can be re-adsorbed back into the matrix, preserving the heterogeneous state of the catalyst. Our results show that QCM is a powerful technique to study in situ the dynamics of the adsorption of POMs on a polymer matrix under different pH conditions.
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- 2015
43. Mechanical behaviour and practical adhesion at a bamboo composite interface: Physical adhesion and mechanical interlocking
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Le Quan Ngoc Tran, A.W. Van Vuure, Ignace Verpoest, G. Brughmans, Christine C. Dupont-Gillain, and C.A. Fuentes
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Bamboo ,Work (thermodynamics) ,Materials science ,Composite number ,General Engineering ,Adhesion ,Interface ,Surface energy ,Stress (mechanics) ,Contact angle ,Ceramics and Composites ,debonding ,Profilometer ,Composite material ,Natural fibres ,fibre-matrix bond - Abstract
Physical adhesion was experimentally determined by measuring contact angles with different liquids on bamboo and glass fibers, using the Wilhelmy technique, and by applying the acid-base theory for calculating the surface energy components and the theoretical work of adhesion. The mechanical strength of the interfaces was assessed by single fibre pull-out tests. In order to consider the real mechanisms of interfacial failure of natural fiber composites, the fibre matrix interfacial bond strength was characterized by the critical local value of interfacial shear stress, τ_d, and the radial normal stress at the interface, σult, at the moment of crack initiation. Both interfacial parameters are used for correlating thermodynamic work of adhesion and practical adhesion. Pull-out tests (taking into account friction), XPS, and profilometry techniques were used to study the influence of rough natural fibre surfaces on the interface between the fibre and a thermoplastic matrix, by comparing the mechanical behaviour at the interface of a smooth optical glass fibre with that of rough natural fibres. The results suggest that the physical and chemical compatibility between the bamboo fibre and the matrix does not improve substantially the composite performance if compared with glass composites. The relatively low off-axis strength of the bamboo fibres is suggested as the main reason for the low stress transfer capability at the fibre-matrix interphase. Furthermore, the pull-out process may be friction-dominated in bamboo fibre systems. ispartof: Composites Science and Technology vol:109 issue:10 pages:40-47 status: published
- Published
- 2015
44. Understanding and controlling type I collagen adsorption and assembly at interfaces, and application to cell engineering
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Christine C. Dupont-Gillain
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Surface Properties ,Nanoporous ,Chemistry ,Nanotechnology ,Surfaces and Interfaces ,General Medicine ,Microscopy, Atomic Force ,Work related ,Collagen Type I ,Colloid and Surface Chemistry ,Adsorption ,Chemical engineering ,Ionic strength ,Desorption ,Self-assembly ,Physical and Theoretical Chemistry ,Cell Engineering ,Type I collagen ,Biotechnology ,Protein adsorption - Abstract
Collagen is a large anisotropic and self-assembling extracellular matrix protein. Understanding and controlling its adsorption and assembly at interfaces is expected to increase our general knowledge of protein adsorption as well as to open the way to the development of biointerfaces of interest for biomaterials science and tissue engineering. The work related to type I collagen adsorption performed in our laboratory over the past twenty years is reviewed. Substrate chemical nature and adsorption conditions (collagen concentration, adsorption duration) were shown to affect collagen adsorbed amount and supramolecular organization. Collagen assemblies were formed starting from the interface, and assembly was favored by hydrophobic substrates and high adsorbed amount. Substrates were designed to better control collagen adsorption and assembly. The spatial control of adsorption was ensured by chemically heterogeneous substrates, which also affected collagen assembly when domains with a dimension smaller than the length of the collagen molecule (i.e. 300nm) were prepared. Mixed polymer brushes were used to achieve a temporal control of adsorption: adsorption and desorption were reversibly triggered by changes of pH and ionic strength. Layer-by-layer assembly of collagen in a nanoporous template was used to elaborate collagen-based nanotubes, which were further deposited on ITO glass substrates by electrophoretic deposition. Finally, the evaluation of cell behavior on the created biointerfaces showed that the control of collagen organization can be successfully used to alter cell behavior.
- Published
- 2014
45. The type and composition of alginate and hyaluronic-based hydrogels influence the viability of stem cells of the apical papilla
- Author
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Julie Vanacker, Christine C. Dupont-Gillain, Laure Lambricht, Julian Leprince, Caroline Bouzin, Pauline De Berdt, Anne des Rieux, Hadi Goldansaz, Véronique Préat, and Anibal R. Diogenes
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Materials science ,Alginates ,Cell Survival ,Surface Properties ,Apoptosis ,Biocompatible Materials ,Cell Line ,Mice ,chemistry.chemical_compound ,Tissue engineering ,In vivo ,Elastic Modulus ,Hyaluronic acid ,Animals ,Humans ,General Materials Science ,Viability assay ,Hyaluronic Acid ,Dental Papilla ,General Dentistry ,Matrigel ,Tissue Scaffolds ,Viscosity ,Photoelectron Spectroscopy ,Stem Cells ,Hydrogels ,Molecular biology ,In vitro ,Drug Combinations ,chemistry ,Mechanics of Materials ,Cell culture ,Self-healing hydrogels ,Microscopy, Electron, Scanning ,Heterografts ,Female ,Proteoglycans ,Collagen ,Laminin ,Stress, Mechanical ,Rheology ,Porosity ,Stem Cell Transplantation ,Biomedical engineering - Abstract
The goal of the present work was to evaluate in vitro and in vivo the influence of various types and compositions of natural hydrogels on the viability and metabolic activity of SCAPs.Two alginate, three hyaluronic-based (Corgel™) hydrogel formulations and Matrigel were characterized for their mechanical, surface and microstructure properties using rheology, X-ray photoelectron spectroscopy and scanning electron microscopy, respectively. A characterized SCAP cell line (RP89 cells) was encapsulated in the different experimental hydrogel formulations. Cells were cultured in vitro, or implanted in cyclosporine treated mice. In vitro cell viability was evaluated using a Live/Dead assay and in vitro cellular metabolic activity was evaluated with a MTS assay. In vivo cell apoptosis was evaluated by a TUNEL test and RP89 cells were identified by human mitochondria immunostaining.Hydrogel composition influenced their mechanical and surface properties, and their microstructure. In vitro cell viability was above 80% after 2 days but decreased significantly after 7 days (60-40%). Viability at day 7 was the highest in Matrigel (70%) and then in Corgel 1.5 (60%). Metabolic activity increased over time in all the hydrogels, excepted in alginate SLM. SCAPs survived after 1 week in vivo with low apoptosis (1%). The highest number of RP89 cells was found in Corgel 5.5 (140cells/mm(2)).Collectively, these data demonstrate that SCAP viability was directly modulated by hydrogel composition and suggest that a commercially available hyaluronic acid-based formulation might be a suitable delivery vehicle for SCAP-based dental pulp regeneration strategies.
- Published
- 2014
46. 3D-printed biodegradable gyroid scaffolds for tissue engineering applications
- Author
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UCL - SST/IMCN/BSMA - Bio and soft matter, UCL - SSS/LDRI - Louvain Drug Research Institute, Germain, Loïc, Fuentes, Carlos A., van Vuure, Aart W., des Rieux, Anne, Dupont-Gillain, Christine C., UCL - SST/IMCN/BSMA - Bio and soft matter, UCL - SSS/LDRI - Louvain Drug Research Institute, Germain, Loïc, Fuentes, Carlos A., van Vuure, Aart W., des Rieux, Anne, and Dupont-Gillain, Christine C.
- Abstract
Fused deposition modeling (FDM), a low-cost and easy-to-use additive manufacturing technique, was used to produce poly(lactic acid) (PLA) gyroid scaffolds. Such morphology was selected for its spring shape, high porosity leading to good nutrient and waste diffusion, and favorable mechanical properties. Printing parameters were optimized and the need of a support material to improve printing was evidenced. The gyroid was compared to the common strut-based structure. Scaffold porosity was measured by micro-CT, and mechanical properties were determined by compression tests, taking into account the effect of geometry, printing resolution, and PLA crystallinity. The impact of scaffold geometry and crystallinity on its degradation was studied in vitro. Porosity of the gyroid structure was 71%, as expected from the printing model. The compression tests showed an isotropic behavior for the gyroid, in contrast with the strut-based scaffold. Upon aging in physiological conditions, gyroid scaffolds retained their integrity during 64 weeks, while control scaffolds lost struts starting from week 33, in a way that depended on crystallinity and printing resolution. Based on these results, the gyroid design is proposed as a suitable mesh architecture for tissue engineering scaffolds that can be elaborated using FDM techniques, to produce low-cost and personalized implants.
- Published
- 2018
47. Antimicrobial peptide encapsulation and sustained release from polymer network particles prepared in supercritical carbon dioxide
- Author
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UCL - SST/IMCN/BSMA - Bio and soft matter, Parilti, Rahmet, Caprasse, Jérémie, Riva, Raphaël, Alexandre, Michaël, Vandegaart, Hélène, Bebrone, Carine, Dupont-Gillain, Christine C., Howdle, Steven M., Jérôme, Christine, UCL - SST/IMCN/BSMA - Bio and soft matter, Parilti, Rahmet, Caprasse, Jérémie, Riva, Raphaël, Alexandre, Michaël, Vandegaart, Hélène, Bebrone, Carine, Dupont-Gillain, Christine C., Howdle, Steven M., and Jérôme, Christine
- Abstract
Antimicrobial peptide loaded poly(2-hydroxyethyl methacrylate) particles were synthesized in supercritical carbon dioxide via one-pot free-radical dispersion polymerisation of 2-hydroxyethyl methacrylate and a cross-linker. Discrete particles with a well-defined spherical morphology and a diameter as low as 450 nm have been obtained in mild conditions. The encapsulation and release of the peptide were confirmed by antimicrobial tests that demonstrated for the first time a sustained release of the peptide from poly(2-hydroxyethyl methacrylate) microgels prepared by one-pot dispersion polymerization in supercritical carbon dioxide and then dispersed in water.
- Published
- 2018
48. Predicting the adhesion strength of thermoplastic/glass interfaces from wetting measurements
- Author
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UCL - SST/IMCN - Institute of Condensed Matter and Nanosciences, Fuentes, C.A., Zhang, Y., Guo, H., Woigk, W., Masania, K., Dransfeld, C., De Coninck, J., Dupont-Gillain, Christine C., Seveno, D., Van Vuure, A.W., UCL - SST/IMCN - Institute of Condensed Matter and Nanosciences, Fuentes, C.A., Zhang, Y., Guo, H., Woigk, W., Masania, K., Dransfeld, C., De Coninck, J., Dupont-Gillain, Christine C., Seveno, D., and Van Vuure, A.W.
- Abstract
To evaluate compatibility between a substrate and a thermoplastic polymer, the established methodology is to estimate their surface composition in terms of surface energy components, utilizing the results of contact angle measurements of probe liquids onto substrate and polymer surfaces at room temperature. Using this methodology,polymer surfaces are studied in solid state, however, during spreading of polymers on a substrate,polymers are in molten state and at high temperature, having different surface energies and more complex polymer/substrate interactions due to polymer chain mobility. This paper presents a model study with practical relevance to predict polymer/substrate compatibility including contact angle measurements at high temperature directly performed between molten thermoplastics; polypropylene (PP), polyvinylidene fluoride (PVDF) and maleic anhydride-grafted polypropylene (MAPP), on smooth glass fibres and plates. The values of total surface energy of thermoplastics at high temperature (260 °C) are down to 57% of that measured at room temperature, which has a strong influence on the wetting prediction. Surface energies of both the polymer and the substrate were found not to be the only factor controlling the wetting behaviour of molten polymers and the level of adhesion with the substrate, but also some intrinsic characteristics of the polymer melt play a role. We also observed that the wetting behaviour of molten MAPP is affected by the maleic anhydride (MA) content, demonstrating dramatically different results to room temperature measurements, which is suspected to be due to the formation of covalent bonds of MA groups with the glass surface enhancing the interface strength beyond the shear strength of MAPP.
- Published
- 2018
49. Equilibrium contact angle measurements of natural fibers by an acoustic vibration technique
- Author
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A.W. Van Vuure, Helge Pfeiffer, Christine C. Dupont-Gillain, C.A. Fuentes, Ignace Verpoest, K. Beckers, and Le Quan Ngoc Tran
- Subjects
Surface (mathematics) ,Materials science ,business.industry ,Contact angle ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Optics ,Wetting transition ,X-ray photoelectron spectroscopy ,chemistry ,Polyethylene terephthalate ,Trigonometric functions ,Wetting ,Fiber ,Composite material ,business - Abstract
tSorption of fluids during typical wetting experiments on natural fibers produces a zero receding contactangle situation, leading to an incomplete analysis of their wetting behavior. An acoustic vibration methodwas used to measure “equilibrium” contact angles on natural bamboo fibers. The correctness of the tech-nique is verified by performing the experiment with polyethylene terephthalate (PET) fibers and films,and comparing these results with the average of the cosine functions of the advancing and receding anglesfor a given system. Surface energies and components of the surface energies of bamboo and PET fiberswere estimated using the “equilibrium” contact angle data of various test liquids by using the acid–baseapproach. The results are in general agreement with X-ray photoelectron spectroscopy (XPS) analysis ofthe fiber’s surface. The findings contribute to a better understanding of the complex phenomena occur-ring during wetting of natural fibers and suggest that the contact angle obtained by forcing relaxationthrough acoustic vibration is a reliable method for study the wetting behavior of natural fibers.
- Published
- 2014
50. Prevalence of vitamin D inadequacy in European women aged over 80 years
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Etienne Cavalier, Olivier Bruyère, Fanny Buckinx, Justine Slomian, Charlotte Beaudart, Sophie Gillain, Jean Petermans, and Jean-Yves Reginster
- Subjects
Fracture risk ,Aging ,Pediatrics ,medicine.medical_specialty ,Health (social science) ,Osteoporosis ,Radioimmunoassay ,White People ,Bone remodeling ,Prevalence ,Vitamin D and neurology ,Humans ,Medicine ,Aged, 80 and over ,Gynecology ,business.industry ,Significant difference ,Vitamin D Deficiency ,medicine.disease ,Europe ,Osteopenia ,Female ,Secondary hyperparathyroidism ,Geriatrics and Gerontology ,business ,Gerontology ,Body mass index - Abstract
Inadequate vitamin D status is associated with secondary hyperparathyroidism and increased bone turnover and bone loss, which in turn increases fracture risk. The objective of this study is to assess the prevalence of inadequate vitamin D status in European women aged over 80 years. Assessments of serum 25-hydroxyvitamin D levels (25(OH)D) were performed on 8532 European women with osteoporosis or osteopenia of which 1984 were aged over 80 years. European countries included in the study were: France, Belgium, Denmark, Italy, Poland, Hungary, United Kingdom, Spain and Germany. Two cut-offs of 25(OH)D inadequacy were fixed
- Published
- 2014
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