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Production scientifique
Matière Molle & Verres
(72) Production(s) de l'année 2019
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Inferring data on cilia spatiotemporal coordination through bronchial epithelium imaging
Auteur(s): Jory M., Fort Aurélie, Casanellas Vilageliu L., Vachier Isabelle, Bourdin Arnaud, Massiera G.
(Affiches/Poster)
Physics and Physiology of Motile Cilia (Bad Honnef, DE), 2019-01-27
Ref HAL: hal-02061766_v1
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Résumé: The mucociliary function of the bronchial epithelium ensures the continuous clearance of the respiratory system. This function relies on two main elements: mucus properties and cilia beating coordination. We work on high speed optical microscopy videos of Human bronchial epithelium from ALI (Air-liquid interface) cultures. We present here a technique based on the tracking of each cilium and on the spatiotemporal analysis of the obtained trajectories. To relate each cilium to its corresponding cell, a clustering method is used. The spatiotemporal coordination can than be quantified both, inside and in-between ciliated cells. In addition the physical parameters can be mapped to observe the heterogeneity of the cilia activity and compare different pathologies.
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Vibrational properties of sodosilicate glasses from first-principles calculations
Auteur(s): Kilymis D., Ispas S., Hehlen B., Peuget S., Delaye Jean-Marc
(Article) Publié:
Physical Review B, vol. 99 p.054209 (2019)
Texte intégral en Openaccess :
Ref HAL: hal-02043157_v1
DOI: 10.1103/PhysRevB.99.054209
WoS: 000459221700002
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5 Citations
Résumé: The vibrational properties of three sodosilicate glasses have been investigated in the framework of density functional theory. The pure vibrational density of states has been calculated for all systems and the different vibrational modes have been assigned to specific atoms or structuralunits. It is shown that the Na content affects several vibrational features as the position and intensity of the R band or the mixing of the rocking and bending atomic motions of the Si-O-Si bridges. The calculated Raman spectra have been found to agree with experimental observations and their decomposition indicated the dominant character of the non-bridging oxygen contribution on the spectra, in particular for the high-frequency band, above 800 cm −1 . The decomposition of the high-frequency Raman feature into vibrations of the depolymerized tetrahedra (i.e. Q n -units) has revealed spectral shapes of the partial contributions that cannot be accounted for by simple Gaussians as frequently assumed in the treatment of experimentally obtained Raman spectra.
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Mucus Microrheology Measured on Human Bronchial Epithelium Culture
Auteur(s): Jory M., Bellouma Karim, Blanc C., Casanellas Vilageliu L., Petit Aurelie, Reynaud Paul, Vernisse Charlotte, Vachier Isabelle, Bourdin Arnaud, Massiera G.
(Article) Publié:
Frontiers In Physics, vol. 7 p.19 (2019)
Texte intégral en Openaccess :
Ref HAL: hal-02025486_v1
DOI: 10.3389/fphy.2019.00019
WoS: WOS:000459130800002
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1 Citation
Résumé: We describe an original method to measure mucus microrheology on human bronchial epithelium culture using optical tweezers. We probed rheology on the whole thickness of mucus above the epithelium and showed that mucus gradually varies in rheological response, from an elastic behavior close to the epithelium to a viscous one far away. Microrheology was also performed on mucus collected on the culture, on ex vivo mucus collected by bronchoscopy, and on another epithelium model. Differences are discussed and are related to mucus heterogeneity, adhesiveness and collection method.
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Rotational diffusion of partially wetted colloids at fluid interfaces
Auteur(s): Stocco A., Chollet B., Wang X., Blanc C., Nobili M.
(Article) Publié:
Journal Of Colloid And Interface Science, vol. 542 p.363-369 (2019)
Texte intégral en Openaccess :
Ref HAL: hal-02024615_v1
DOI: 10.1016/j.jcis.2019.02.017
WoS: 000461536400040
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10 Citations
Résumé: Hypothesis: Rotational Brownian diffusions of colloidal particles at a fluid interface play important roles in particle self-assembly and in surface microrheology. Recent experiments on translational Brownian motion of spherical particles at the air-water interface show a significant slowing down of the translational diffusion with respect to the hydrodynamic predictions (Boniello et al., 2015). For the rotational diffusions of partially wetted colloids, slowing down of the particle dynamics can be also expected.Experiments: Here, the rotational dynamics of Janus colloids at the air-water interface have been experimentally investigated using optical microscopy. Bright field and fluorescent microscopies have been used to measure the in-plane and out-of-plane particle rotational diffusions exploiting the Janus geometry of the colloids we fabricated.Findings: Our results show a severe slowing down of the rotational diffusion Dr,⊥ connected to the contact line motion and wetting-dewetting dynamics occurring on particle regions located at opposite liquid wedges. A slowing down of the particle rotational diffusion about an axis parallel to the interfacial normal Dr,|| was also observed. Contact line fluctuations due to partial wetting dynamics lead to a rotational line friction that we have modelled in order to describe our results.
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pH-mediated control over the mesostructure of ordered mesoporous materials templated by polyion complex micelles
Auteur(s): Molina Emilie, Mathonnat M., Richard Jason, Lacroix-Desmazes Patrick, In M., Dieudonne-George P., Cacciaguerra Thomas, Gerardin Corine, Marcotte Nathalie
(Article) Publié:
Beilstein Journal Of Nanotechnology, vol. 10 p.144-156 (2019)
Texte intégral en Openaccess :
Ref HAL: hal-01992289_v1
DOI: 10.3762/bjnano.10.14
WoS: 000455446300001
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2 Citations
Résumé: Ordered mesoporous silica materials were prepared under different pH conditions by using a silicon alkoxide as a silica source and polyion complex (PIC) micelles as the structure-directing agents. PIC micelles were formed by complexation between a weak poly-acid-containing double-hydrophilic block copolymer, poly(ethylene oxide)-b-poly(acrylic acid) (PEO-b-PAA), and a weak poly-base, oligochitosan-type polyamine. As both the micellization process and the rate of silica condensation are highly dependent on pH, the properties of silica mesostructures can be modulated by changing the pH of the reaction medium. Varying the materials synthesis pH from 4.5 to 7.9 led to 2D-hexagonal, wormlike or lamellar mesostructures, with a varying degree of order. The chemical composition of the as-synthesized hybrid organic/inorganic materials was also found to vary with pH. The structure variations were discussed based on the extent of electrostatic complexing bonds between acrylate and amino functions and on the silica condensation rate as a function of pH.
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Swelling behaviour of core-shell microgels in H2O, analysed by temperature-dependent FTIR spectroscopy
Auteur(s): Wiehemeier Lars, Cors M., Wrede Oliver, Oberdisse J., Hellweg Thomas, Kottke Tilman
(Article) Publié:
Physical Chemistry Chemical Physics, vol. 21 p.572-580 (2019)
Ref HAL: hal-01985848_v1
DOI: 10.1039/c8cp05911j
WoS: WOS:000454922300002
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10 Citations
Résumé: Stimuli-responsive microgels are colloidal particles and promising candidates for applications such as targeted drug delivery, matrices for catalysts, nanoactuators and smart surface coatings. To tailor the response, the architecture of microgels is of paramount importance with respect to these applications. Statistical copolymer microgels based on N-isopropylmethacrylamide (NiPMAM) and N-n-propylacrylamide (NnPAM) show a cooperative phase transition leading to a collapse at a specific temperature. Interestingly, some core-shell microgel particles reveal a linear response of the hydrodynamic radius with temperature. Such observations were made by photon correlation spectroscopy (PCS), which is limited to the diffusion properties dominated by the particle shell. In this work we investigate the molecular hydration within the network of microgels in H2O by temperature-dependent FTIR spectroscopy. The phase transition temperature wasdetermined by the shift in frequency of the NH bending vibration in homopolymer and statistical copolymer microgels and the results are in accordance with those from PCS. In contrast, experiments on core-shell particles show a broadening and shift of the respective phase transition temperatures of core and shell indicating an interaction of core and shell polymers on a molecular level that extends far into the core. In conclusion, temperature-dependent FTIR spectroscopy is a convenient approach to elucidate the internal architecture of complex microgel particles in H2O.
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Probing shear-induced rearrangements in Fourier space. I. Dynamic light scattering
Auteur(s): Aime S., Cipelletti L.
(Article) Publié:
Soft Matter, vol. 15 p.200-212 (2019)
Texte intégral en Openaccess :
Ref HAL: hal-01982836_v1
DOI: 10.1039/c8sm01563e
WoS: WOS:000454947400016
Exporter : BibTex | endNote
5 Citations
Résumé: Understanding the microscopic origin of the rheological behavior of soft matter is a long-lastingendeavour. While early efforts concentrated mainly on the relationship between rheology and structure,current research focuses on the role of microscopic dynamics. We present in two companion papers athorough discussion of how Fourier space-based methods may be coupled to rheology to shed light onthe relationship between the microscopic dynamics and the mechanical response of soft systems. In thisfirst companion paper, we report a theoretical, numerical and experimental investigation of dynamiclight scattering coupled to rheology. While in ideal solids and simple viscous fluids the displacement fieldunder a shear deformation is purely affine, additional non-affine displacements arise in many situationsof great interest, for example in elastically heterogeneous materials or due to plastic rearrangements.We show how affine and non-affine displacements can be separately resolved by dynamic lightscattering, and discuss in detail the effect of several non-idealities in typical experiments.
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