Engineering of Silica Thin-Film Nanoporosity via Alkali-Ion-Assisted Reconstruction

International audienc

Suppressing Structural Colors of Photocatalytic Optical Coatings on Glass: The Critical Role of SiO₂

International audienceThe appearance of structural colors on coated-glass is a critical esthetical drawback toward industrialization of photocatalytic coatings on windows for architecture or automobile. Herein we describe a rational approach to suppress the structural color of mesoporous TiO2-based coatings preserving photoactivity and mechanical stiffness. Addition of SiO2 as third component is discussed. TixSi(1-x)O2 mesoporous coatings were fabricated by one-step liquid deposition process through the evaporation induced self-assembling and characterized by GI-SAXS, GI-WAXS, electron microscopies, and in situ Environmental Ellipsometry Porosimetry. Guided by optical simulation, we investigated the critical role of SiO2 on the optical responses of the films but also on the structural, mechanical, and photocatalytic properties, important requirements to go toward real applications. We demonstrate that adding SiO2 to porous TiO2 allows tuning and suppression of structural colors through refractive index matching and up to 160% increase in mechanical stiffening of the films. This study leads us to demonstrate an example of “invisible” coating, in which the light reflection is angle- and thickness-independent, and exhibiting high porosity, mechanical stiffness, and photoactivity

Engineering Functionality Gradients by Dip Coating Process in Acceleration Mode

International audienceIn this work, unique functional devices exhibiting controlled gradients of properties are fabricated by dip-coating process in acceleration mode. Through this new approach, thin films with ``on-demand'' thickness graded profiles at the submillimeter scale are prepared in an easy and versatile way, compatible for large-scale production. The technique is adapted to several relevant materials, including sol-gel dense and mesoporous metal oxides, block copolymers, metal-organic framework colloids, and commercial photoresists. In the first part of the Article, an investigation on the effect of the dip coating speed variation on the thickness profiles is reported together with the critical roles played by the evaporation rate and by the viscosity on the fluid draining-induced film formation. In the second part, dip-coating in acceleration mode is used to induce controlled variation of functionalities by playing on structural, chemical, or dimensional variations in nano- and microsystems. In order to demonstrate the full potentiality and versatility of the technique, original graded functional devices are made including optical interferometry mirrors with bidirectional gradients, one-dimensional photonic crystals with a stop-band gradient, graded microfluidic channels, and wetting gradient to induce droplet motion

High extracellular calcium induced valvular calcification through a calcium sensing receptor dependent mechanism

European-Society-of-Cardiology Congress, Munich, GERMANY, AUG 25-29, 2018International audienc

Direct, acute effects of Klotho and FGF23 on vascular smooth muscle and endothelium.

Chronic kidney disease (CKD) is regarded as a state of Klotho deficiency and FGF23 excess. In patients with CKD a strong association has been found between increased serum FGF23 and mortality risk, possibly via enhanced atherosclerosis, vascular stiffness, and vascular calcification. The aim of this study was to examine the hypothesis that soluble Klotho and FGF23 exert direct, rapid effects on the vessel wall. We used three in vitro models: mouse aorta rings, human umbilical vein endothelial cells, and human vascular smooth muscle cells (HVSMC). Increasing medium concentrations of soluble Klotho and FGF23 both stimulated aorta contractions and increased ROS production in HVSMC. Klotho partially reverted FGF23 induced vasoconstriction, induced relaxation on phosphate preconstricted aorta and enhanced endothelial NO production in HUVEC. Thus Klotho increased both ROS production in HVSMC and NO production in endothelium. FGF23 induced contraction in phosphate preconstricted vessels and increased ROS production. Phosphate, Klotho and FGF23 together induced no change in vascular tone despite increased ROS production. Moreover, the three compounds combined inhibited relaxation despite increased NO production, probably owing to the concomitant increase in ROS production. In conclusion, although phosphate, soluble Klotho and FGF23 separately stimulate aorta contraction, Klotho mitigates the effects of phosphate and FGF23 on contractility via increased NO production, thereby protecting the vessel to some extent against potentially noxious effects of high phosphate or FGF23 concentrations. This novel observation is in line with the theory that Klotho deficiency is deleterious whereas Klotho sufficiency is protective against the negative effects of phosphate and FGF23 which are additive

Tissue inhibitor of metalloproteinases-1 signalling pathway leading to erythroid cell survival.

Tissue inhibitors of metalloproteinases (TIMP) are specific inhibitors of matrix metalloproteinases (MMPs) and thus participate in maintaining the balance between extracellular matrix deposition and degradation in several physio-pathological processes. Nevertheless, TIMP must be regarded as multifunctional proteins involved in cell growth, angiogenesis and apoptosis. The molecular mechanisms induced by TIMP remain largely unknown. In the present study, we provide evidence that TIMP-1 induces a significant anti-apoptotic effect in the human erythroleukaemic cell line UT-7 and in the murine myeloid cell line 32D. Using specific kinases inhibitors, we show that TIMP-1-mediated cell survival is dependent upon Janus kinase (JAK) 2 and phosphoinositide 3-kinase (PI 3-kinase) activities. By transient transfection of dominant-negative Akt in UT-7 cells, we demonstrate that this kinase is crucial for the TIMP-1 anti-apoptotic effect. Moreover, TIMP-1 enhances specific phosphorylation of both Akt and Bad (Bcl-2/Bcl-X(L)-antagonist, causing cell death) in a PI 3-kinase-dependent manner and, besides, controls the level of the anti-apoptotic protein Bcl-X(L). We conclude that TIMP-1 induces haematopoietic cell survival via the JAK2/PI 3-kinase/Akt/Bad pathway

Determination and Modulation of Total and Surface Calcium-Sensing Receptor Expression in Monocytes In Vivo and In Vitro

<div><p>Expression of the calcium-sensing receptor (CaSR) has previously been demonstrated in human circulating monocytes (HCM). The present study was designed to measure CaSR expression in HCM and to examine its potential modulation by pro-inflammatory cytokines, Ca2+, vitamin D sterols in U937 cell line. Twenty healthy volunteers underwent blood sampling with subsequent isolation of peripheral blood mononuclear cells (PBMC) at 3 visits. Flow cytometry analysis (FACS) was performed initially (V1) and 19 days later (V2) to examine intra- and intersubject fluctuations of total and surface CaSR expression in HCM and 15 weeks later (V3) to study the effect of vitamin D supplementation. <i>In vitro</i> experiments were conducted to assess the effects of pro-inflammatory cytokines, calcidiol, calcitriol and Ca2+ on CaSR expression in U937 cell line. By FACS analysis, more than 95% of HCM exhibited cell surface CaSR staining. In contrast, CaSR staining failed to detect surface CaSR expression in other PBMC. After cell permeabilization, total CaSR expression was observed in more than 95% of all types of PBMC. Both total and surface CaSR expression in HCM showed a high degree of intra-assay reproducibility (<3%) and a moderate intersubject fluctuation. In response to vitamin D supplementation, there was no significant change for both total and surface CaSR expression. In the <i>in vitro</i> study, U937 cells showed strong total and surface CaSR expression, and both were moderately increased in response to calcitriol exposure. Neither total nor surface CaSR expression was modified by increasing Ca2+ concentrations. Total CaSR expression was concentration dependently decreased by TNFα exposure. In conclusion, CaSR expression can be easily measured by flow cytometry in human circulating monocytes. In the <i>in vitro</i> study, total and surface CaSR expression in the U937 cell line were increased by calcitriol but total CaSR expression was decreased by TNFα stimulation.</p></div

Vascular reactivity on aortic rings <i>ex vivo.</i>

<p>Direct effects of phosphate (1.0–3.0 mM), Klotho (0–2.0 nM) and FGF23 (0–400 ng/ml) on isolated aortic rings in absence or in the presence of ERK inhibitor, U0126 (10 μM). Contraction values are expressed as percentage of the contraction obtained with 70 mM KCl. ** p<0.0001 vs. mouse vessels alone. N, 4 per experiment.</p

Direct effects of phosphate, Klotho and FGF23 on vascular reactivity and on H₂O₂ concentration.

<p>A.Vascular reactivity on aortic rings <i>ex vivo.</i> Direct effects of phosphate (1.0–3.0 mM), Klotho (0–2.0 nM) and FGF23 (0–400 ng/ml) on isolated aortic rings in absence or in the presence of ROS inhibitor, dimethylthiourea (10 mM). Contraction values are expressed as percentage of the contraction obtained with 70 mM KCl. * p<0.001, ** p<0.0001 vs. mouse vessels alone. N, 4 per experiment. B. Direct effects of phosphate (2.0 mM), Klotho (1.6 nM) and FGF23 (10 ng/ml), alone or associated, on H₂O₂ concentration in human umbilical vein endothelial cells (HUVECs) and human vascular smooth muscle cells (HVSMCs). * p<0.0005 vs. HVSMCs control group, $ p<0.005 vs HVSMCs phosphate group, £ p<0.05 vs. HUVECs control group. N, 7 per experiment.</p