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International audience; Alpha2-macroglobulin (α2M) is a physiological macromolecule that facilitates the clearance of many proteinases, cytokines and growth factors in human. Here, we explored the effect of induced forms of α2M on anticoagulant drugs. Gla-domainless factor Xa (GDFXa) and methylamine (MA)-induced α2M were prepared and characterized by electrophoresis, immunonephelometry, chromogenic, clot waveform and rotational thromboelastometry assays. Samples from healthy volunteers and anticoagulated patients were included. In vivo neutralization of anticoagulants was evaluated in C57Bl/6JRj mouse bleeding-model. Anticoagulant binding sites on induced α2M were depicted by computer-aided energy minimization modeling. GDFXa-induced α2M neutralized dabigatran and heparins in plasma and whole blood. In mice, a single IV dose of GDFXa-induced α2M following anticoagulant administration significantly reduced blood loss and bleeding time. Being far easier to prepare, we investigated the efficacy of MA-induced α2M. It neutralized rivaroxaban, apixaban, dabigatran and heparins in spiked samples in a concentration-dependent manner and in samples from treated patients. Molecular docking analysis evidenced the ability of MA-induced α2M to bind non-covalently these compounds via some deeply buried binding sites. Induced forms of α2M have the potential to neutralize direct oral anticoagulants and heparins, and might be developed as a universal antidote in case of major bleeding or urgent surgery. © 2021 Elsevier B.V.

International audience; Mesoporous silica SBA-15 was functionalized with various amines and then doped with copper II cation (Cu2+). The modified materials were tested for the retention of CO2 at room temperature using temperature-programmed desorption (CO2-TPD). Several parameters affecting the CO2 retention capacity (CRC) such as the nature of amine groups, repetitive adsorption-desorption cycles and dispersion of copper were investigated. CO2-TPD and H2O-TPD allowed correlating the hydrophilic character with the CO2 retention capacity. The obtained results showed that amine-functionalized mesoporous materials containing their own moisture exhibit higher effectiveness in the retention of CO2. Triamine-functionalized SBA-15 displayed the highest CRC value as a result of the increase of the number of adsorption sites. Material reuse in three adsorption/desorption cycles revealed high stability with a slight decrease in CRC. The dispersion of copper induced a progressive decrease in the CRC value. The CRC decreased with increasing Cu2+ content due to competitive complexation of Cu2+ by the amino groups.

Resume Le medecin en charge d’un patient temoin de Jehovah qui refuse la transfusion est pris entre deux injonctions contradictoires : le respect de la volonte du patient et l’assistance a personne en danger. La seconde emporte la decision sous reserve que la decision de transfusion soit adaptee et proportionnee a la situation hemorragique. Dans ce contexte le seuil transfusionnel est inferieur a celui habituellement recommande puisqu’il correspond au risque vital. La volonte du patient doit etre recueillie et le projet therapeutique doit etre clairement explique au patient, trace dans le dossier et respecte. Les techniques d’autotransfusion et l’usage de certains produits derives du sang sont admis par certains temoins de Jehovah sous couvert d’explications.

International audience; Amorphous carbon nitride (a-CNx) thin films were used for the first time as electrode materials in the elaboration of biofuel cell cathodes as a consequence of i) the natural presence of amine type functional groups and ii) the ease to generate carboxylic acid groups on their surface with the help of an anodic treatment. Their rich surface chemistry was exploited to investigate the influence of the orientation of immobilised laccase on their bioelectrocatalytic activity towards oxygen reduction reaction (ORR) in a direct electron transfer configuration. Among four different immobilisation strategies leading to a statistical control of the orientation and tested in this work, spontaneous adsorption of natural laccase on pristine a-CNx provided the smallest current density value (3.5 μA cm−2) whereas covalent grafting of oxidised laccase on anodically treated a-CNx via imine and amide bond formation using a coupling agent led to a much higher but still low 44.6 μA cm−2 current density. This substantial improvement of the current density value measured for ORR confirms that the orientation of immobilised laccase exerts a measurable influence on its bioelectrocatalytic activity towards ORR.In parallel, the surface coverage rate of enzymes showing such activity was estimated as a function of the immobilisation method by using four different techniques (current density, activity towards ABTS, XPS and AFM). It was found that only a small fraction (7.1% to the most) of the electrode surface is covered with active enzymes, whatever the immobilisation method, whereas an enzyme population corresponding (almost) to a full enzyme monolayer was actually immobilised. This observation is crucial because it strongly suggests that the development of innovative immobilisation strategies allowing an increase of the active enzyme fraction through a simultaneous optimisation of the bioelectrocatalytic activity of the enzyme and of its electronic communication with the electrode offers much more promising perspectives than the control of the orientation of the immobilised enzyme population on its own.

Resume Le medecin en charge d’un patient temoin de Jehovah qui refuse la transfusion est pris entre deux injonctions contradictoires : le respect de la volonte du patient et l’assistance a personne en danger. La seconde emporte la decision sous reserve que la decision de transfusion soit adaptee et proportionnee a la situation hemorragique. Dans ce contexte le seuil transfusionnel est inferieur a celui habituellement recommande puisqu’il correspond au risque vital. La volonte du patient doit etre recueillie et le projet therapeutique doit etre clairement explique au patient, trace dans le dossier et respecte. Les techniques d’autotransfusion et l’usage de certains produits derives du sang sont admis par certains temoins de Jehovah sous couvert d’explications.

International audience; Thickness variations of poly(3,4-ethylenedioxythiophene) (PEDOT) thin films placed under potential conditioning were measured with the help of electrochemical atomic force microscopy (EC-AFM). In this purpose, in-situ AFM operating in the contact mode was coupled with either cyclic voltammetry (CV) or advanced cyclic voltammetry (AdCV). A PEDOT functionnalized platinum electrode was used simultaneously as a sample for in-situ AFM measurements and a working electrode in a usual three electrode electrochemical setup. PEDOT films were electrodeposited with the help of the CV technique from lithium perchlorate aqueous solutions. From these EC-AFM investigations, brand new PEDOT films were found to be anion exchangers, in good agreement with conclusions of investigations reported in literature. Unexpectedly, PEDOT films having undergone a comprehensive electrochemical cycling (i.e. an electrochemical aging) in a potential range encompassing narrowly their redox process by using tens of CV or AdCV potential cycles behave as cation exchangers. Such observation strongly suggests that the electrochemo-mechanical and ion exchange behaviours of PEDOT can be both switched by simply using a potential cycling. Interestingly, the initial steps of this switching process were observed on a brand new PEDOT film during 26 consecutive CV scans. In the course of this process still ongoing at the end of the 26th cycle, a second swelling peak appears and grows progressively beside the initial swelling peak attributed to an anion exchange behaviour. This leads to a dual ion exchange behaviour for the resulting PEDOT film within the explored potential range. Indeed, this new swelling peak can be attributed to a cation exchange behaviour from the comparison of the potential dependant chronothicknograms and corresponding voltathicknograms with those obtained previously in this work.

Introduction Sarcopenia is defined by both decrease in muscle mass and function leading to fragility and death. Early identification of sarcopenic patients may help to improve morbidity and mortality of such patients. No data are available in patients with severe aortic stenosis (AS) waiting for trans-cutaneaous aortic-valve implantation (TAVI). The objective of the present study was to evaluate the prevalence of sarcopenia and its impact in patients with severe AS. Methods In a single center prospective study, sarcopenia screening and its impact were systematically conducted in 127 patients with AS waiting for TAVI, according to the EWGSOP criteria and algorithm. Results The prevalence of sarcopenia was 53.5%. Sarcopenic patients were older (83 ± 4.9 vs. 81.3 ± 5.8 years old, P = 0.02), with a lower body mass index (26.4 ± 3.9 vs. 31.0 ± 5.8 kg/m2, P Conclusion Over 50% of patients with aortic stenosis waiting for TAVI are sarcopenic. More data and studies are needed to evaluate the benefit of TAVI in sarcopenic patients and the management of such patients.

Introduction The prediction of fluid responsiveness in paediatrics and infants remains problematic. We sought to test the validity of the measurement of StcO 2 as a predictive parameter of fluid responsiveness in infants less than one year old during non-cardiac surgery. Materials and methods This was a prospective observational study on infants aged less than 1 year without any cardiac disease during the intraoperative period of non-cardiac surgery. Cerebral oxygen saturation (StcO 2 ) was obtained using infrared spectroscopic INVOS ® monitors. Reference values were obtained 10 minutes after intubation. Fluid load indications were dependent on the anaesthesiologist caring for the patient. The objective of this study was to determine the accuracy of StcO 2 values before vascular filling (StcO 2 B) and the difference in StcO 2 values between the reference value and before vascular filling (ΔStcO 2 ), in predicting vascular filling response defined as an increase in mean arterial pressure over 15%. Statistical analysis was carried out using ROC curve analysis with determination of grey zones. Results Twenty-nine patients were eligible for this study, 23 were included in the study (one intravenous fluid challenge per patient). There were 10 responders and 13 non-responders. The StcO 2 B and the ΔStcO 2 were significantly different between responders and non-responders. Analysis of the ROC curve found an area under the curve of 0.75 [95% CI 0.56 to 0.95] for StcO 2 B and 0.83 [95% CI 0.66 to 0.99] for ΔStcO 2 . The grey-areas were [59–78] and [16–28] for StcO 2 B and ΔStcO 2 . Conclusion NIRS appears to be an interesting additional tool for predicting an increase of blood pressure in response to intraoperative fluid challenge in infants less than one year old.

International audience; Cerium oxide (CeO2) nanoparticles (NPs) possessing defined size and crystallinity have been synthe-sised by a co-precipitation method. The effect of several parameters, such as the nature of the solventand the calcination process, on the crystallite size was studied by XRD, TEM and BET methods. TheseCeO2nanoparticles were then incorporated in dodecylsulfate (DS) doped PPy films during their elec-trodeposition in potentiodynamic conditions in order to produce PPy-DS/CeO2NPs nanocomposite thinfilms on gold coated quartz crystals. Simultaneous EQCM experiments revealed successful incorpora-tion of increasing amounts of cerium oxide nanoparticles in the polypyrrole matrix during each of theconsecutive CV scans. This was confirmed using FEG-SEM and EDS microanalysis.The ion exchange phenomena occurring in the resulting nanocomposite materials were studied byac-electrogravimetry in NaCl aqueous electrolyte. PPy-DS films appear to be mainly cation exchang-ers, independently from the incorporation of CeO2nanoparticles (NPs), even though chloride anions insmaller amounts, and free water molecules, are simultaneously transferred at the film/electrolytic solu-tion interface. This study also reveals that the kinetics of Cl−ion insertion occurring at the film/electrolyteinterface upon oxidation is persistently slower in PPy-DS/CeO2NPs films than in PPy-DS films through-out the entire potential window of investigation. However, the relative concentration changes of Cl−ions in PPy-DS/CeO2NPs films is about two times greater than that occurring in pristine PPy-DS films.Such conclusion tends to demonstrate that CeO2NPs have the ability to modify the morphology of elec-trodeposited PPy-DS thin films as well as their subsequent permeability towards ions contained in theelectrolytic solution, possibly via the perturbation of polymer chain interactions and organisation.

International audience; A fluorocarbonyl terminated ferrocene based redox probe was synthesized and characterized using infrared spectroscopy and nuclear magnetic resonance. It was then successfully grafted on various amorphous carbon nitride (a-CN x) samples (0.12 d x d 0.27) via the formation of a -CO-NH-type linkage with surface amine groups, whose spontaneous formation on the surface of a-CN x materials was thus proved and exploited. Cyclic voltammetry experiments were carried out in an acidic aqueous solution in the presence of this freely diffusing redox probe, in order to identify its electrochemical behavior. By comparison, CV experiments carried out on the modified a-CN x electrodes in the same blank electrolytic solution undoubtedly confirmed the presence of electroactive sub-monolayers, in spite of distortions of the resulting voltammograms. These latter were shown to reflect the influence of bulk atomic nitrogen content on the electrochemical reactivity of a-CN x materials. The grafted surface amine percentage deduced from the charge passed during oxidation of grafted ferrocene moieties was found to decrease from 6.5 % for a-CN 0.12 down to 1.1 % for a-CN 0.27 . This trend is expected to reflect the trend in surface concentration of reactive amine groups as a function of bulk atomic nitrogen content.

International audience; Our purpose is here to produce a large area 3D junction between anatase type TiO2 and polypyrrole (PPy) in a Ti/TiO2 nanotube array (NTA)/PPy assembly with the help of electrochemical methods only. We report herein the influence of light and background salt on the electrochemical polymerization of pyrrole from aqueous electrolytic solutions on titanium oxide NTAs, a well-known large specific area n-type semiconductor substrate. As titanium dioxide is known to be poorly conducting in the anodic potential range, we confirmed that light is able to initiate a polymerization process of pyrrole, at a moderately high anodic potential. For comparison with results obtained in sodium dodecylbenzenesulfonate (SDBS) at micellar concentration, we used here also lithium perchlorate as background salt at a 0.1 M concentration, and PPy growth was found to be faster in the presence of LiClO4. Moreover in the latter case polypyrrole could be initiated in the dark as well, yet at an enhanced deposition rate under UV light. In the two solutions. the resulting polypyrrole films were found to be electroactive, i.e. able to undergo electrochemically driven doping/undoping processes, yet with a higher electroactivity for the film obtained in LiClO4. SEM-FEG and Raman spectroscopy experiments confirmed respectively that i) the initial steps of the photo-assisted electrodeposition of polypyrrole films occur first at the mouth of the titanium dioxide nanotubes, before leading to the well-known cauliflower-like morphology for PPy and ii) PPy is systematically produced in a doped state.

International audience; In this work, a-CNx films prepared by DC magnetron sputtering on stainless steel substrate have been investigated as electrode materials. While their wide potential window was confirmed as a property shared by boron doped diamond (BDD) electrodes, their electrochemical activity with respect to fast and reversible redox systems, [Ru(NH3)(6)](3+)/(2+), [Fe(CN)(6)](3-)/(4-) and [IrCl6](2-)/(3-), was assessed by Electrochemical Impedance Spectroscopy (EIS) after cathodic or anodic electrochemical pre-treatments or for as grown samples. It was shown for the three systems that electrochemical reactivity of the a-CNx films was improved after the cathodic pre-treatment and degraded after the anodic one, the apparent heterogeneous rate constant ko(app) being decreased by at least one order of magnitude for the latter case. A high ko(app), value of 0.11 cm s(-1) for [IrCl6](2-)/(3-) was obtained, close to the highest values found for BDD electrodes.

International audience; Electrochemical activity, morphology and surface electrical conductivity of Boron-Doped Polycrystalline Diamond films prepared by MPCVD have been investigated. Heterogeneous apparent rate constants of three different redox systems, [Fe(CN)(6)](3-/4-), [IrCl(6)](2-/3-) and [Ru(NH(3))(6)](3+/2+) have been measured by both Cyclic Voltammetry and Electrochemical Impedance Spectroscopy on < 100 > textured films with a predominance of (111) faces: first measurements have been done with [Fe(CN)(6)](3-/4-) only on as grown samples, and secondly after a mild electrochemical pretreatment the three redox systems have been investigated. "As-grown" samples showed a moderate average activity which was related to the presence of a minority of electronically conducting areas among insulating zones. Electrochemical treatment in neutral conditions substantially increased the activity and heterogeneous apparent rate constants k(app) for the three couples were measured in the range of 10(-2) cm s(-1) with a good stability in time. Current-sensing AFM images performed ex situ showed that the electrochemically pre-treated material presented a high superficial conductivity whereas the grown sample showed major area of low conductivity.

The local wall shear stress (WSS) mapping in the rotating cage (RC) has been obtained from measuring the diffusion current due to the electrochemical reduction of methyl viologen used as tracer system for both Newtonian and non-Newtonian solutions. The latter were achieved with oleyltrimethyl ammonium, a cationic surfactant, and sodium salicylate as counter-ion, forming thread-like micelles which induce drag reduction conditions. The maximum WSS values were detected in the middle of the coupon in agreement with observation of corroded coupons in erosion–corrosion tests. Maximum values of 65% for drag reduction were measured at the same locations.

We studied biofilm formation on stainless steel occurring in a drinking water distribution system which operated in parallel at 20 and 37 °C, in order to focus on the effect of temperature rather than on other operational and water quality parameters. A surface conditioning step was followed as a function of time on this material until adhesion of bacterial colonies by using microscopic methods: scanning electron microscopy (SEM) and atomic force microscopy (AFM); a spectroscopic method: polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS), and an electrochemical method: rotating disk electrode (RDE). Correlations between surface analysis, the duration of immersion of the sample and the influence of temperature have been identified clearly before bacterial adhesion. In cold water, these results showed an initial conditioning step of surface occurring during the first 8 days, with detection of superficial acidic functions grafted on surface, until adsorption of proteins. After 12 days, formation of independent bacteria microcolonies, reaching 2-3 μm in length was observed. In tepid water, the first step was reduced to 2 days during which carbonates, acidic functions, and proteins were detected. After 90days, the biofilm entered in a stable population state, which appeared as a bacteria rich film, including possibly Legionella. The spatial variation of the biofilm was limited as deduced from the thickness determination (about 4 μm for 3-month period), using a RDE. The combination of these different techniques confirms successive steps for biofilm formation on stainless steel in a tap water. Then, we scrutinized the external near environment of bacteria including extracellular polymeric substances (EPS) and then further characterize the morphology of dominant bacteria (shape, size, flagellum) on gold substrate by AFM in air.

An unknown corrosion process producing dendrites was recently found to take place at copper patterns immersed in oxalic acid aqueous solutions in the course of the post-chemical–mechanical polishing of integrated microcircuits (ICs). We report here investigations of this corrosion phenomenon in ICs using atomic force microscopy (AFM), cyclic voltammetry and Raman spectroscopy. AFM first allowed an accurate morphological characterisation of the copper patterns and their surroundings while cyclic voltammetry was used to identify their electrochemical reactivity in oxalic acid aqueous solutions. In situ AFM experiments carried out in this same aqueous media in open circuit conditions unambiguously showed a progressive and partial dissolution of copper patterns as well as the formation of a ring type structure. Raman spectroscopy was used on gold supported electrogenerated copper films to identify the precipitation or adsorption products resulting from the electrochemistry of the copper/oxalic acid system as a function of the applied potential and the pH of the oxalic acid aqueous solutions. The collected results rather suggest a two-step galvanic corrosion phenomenon involving the tantalum barrier, copper seed layer and electrodeposited copper.

Duplex polypyrrole (PPy) films have been electrochemically synthesized on iron to be used as protective coatings against corrosion. The inner film was doped with tetraoxalate anions and the outer one with dodecyl sulfate anions. The protection against corrosion of this coating was tested in sodium chloride solutions: an increase in the protection time by one order of magnitude with respect to an oxalate-doped PPy film of the same total thickness was measured. The proposed mechanism was based on a change in the permselectivity of the film from anion exchange to cation exchange, thus preventing from the ingress of corrosive chloride anions.

We report here on the appropriate analysis of some examples of interfering compounds that should be done to assess the specificity of the electrochemical sensing of nitric oxide in solution. To do so, we describe the design of a nickel porphyrin and Nafion(R)-coated carbon microfibre and discuss the methodological approach in examining interfering compounds.

A preliminary evaluation of the electrochemical behaviour of phenolic calix[n]arenes (n=4,6) possessing either H- or tert-butyl functionality at the para-phenol position has been undertaken by cyclic voltammetry. Electrochemical activity of these calixarenes is an inherent property, due to oxidation of the phenolic moiety in both types of calixarene. Oxidation of the p-H-substituted calixarenes leads to an electrode passivation process whereas oxidation of the p-t-butyl-substituted calixarenes does not. The former is attributed to electropolymerisation via intermolecular reaction of calixarene phenoxy radical species at the para-position to produce a non-conducting deposit on the electrode surface. This process is not possible with the p-t-butyl-substituted calixarenes. Keywords: Calixarene, Oxidation, Passivation, Phenol, Electropolymerisation

The water-soluble calixarene p-hexasulfonato-calix[6]arene 1 was subjected to voltammetric studies of its oxidation. At glassy carbon or platinum electrodes in aqueous electrolyte solutions, oxidation was observed at E>0.7 V versus SCE in pH 2 solution. On glassy carbon, a stable derivatisation of the electrode surface was inferred from the perturbation in the electrochemistry of the anionic probe species Fe(CN)63−/4− while the electrochemistry of the cationic probe Ru(NH3)63+/2+ was unchanged. Investigation of the electrochemistry of 1 as a function of pH (2

The electrochemical oxidation of tetraethyl ester p-tert-butyl calix[4]arene 1 was observed in acetonitrile solution at a platinum electrode, using either cyclic or square wave voltammetry. The oxidation occurred in a number of processes, with the lowest, process I at a peak potential of 1.10 V vs. Ferrocene, being the best defined response. This was attributed to the one-electron oxidation of the aryl ether functionality present in the calixarene and so should provide a route to the electrochemical detection of calixarenes in non-aqueous mixtures. The oxidation behaviour was dependent on the presence of alkali metal cations in solution. Shifts in the oxidation potentials observed were in good agreement with the order of selectivity for the alkali metal cations. Keywords: Calixarene, Electrochemical oxidation, Aryl ether, Ionic recognition, Sensor

The pyrrole-containing 1,1′-bis(bipyridyl)-substituted derivative of ferrocene L exhibits electrochemical recognition properties towards CuI and NiII in homogeneous solution. PolyL films synthesised by its oxidative electropolymerisation are able to coordinate CuI ions, whereas they do not display coordinating ability for NiII. In contrast, electropolymerisation of L in the presence of CuI or NiII ions readily obtain pre-structured metallated films. These films can be demetallated electrochemically, and then partially remetallated.

Examples of several molecular redox-active receptors containing a ferrocene redox centre and crown ether or bipyridyl moieties as binding site are presented. Their electrochemical recognition properties towards groups I and II (crown ether-based receptors) and Cu+ (2,2′-bipyridine-based receptors) metal cations have been investigated by cyclic voltammetry in homogeneous solution. Among the four ferrocene-crown ether studied, Fcc3 allowed the effective amperometric recognition of Ba2+ and Ca2+ cations owing to the growth of a new redox peak system at the expense of the original Fc/Fc+ wave (two-wave behavior). In addition, comparison of the electrochemical features in the presence of Cu+ cations of ferrocene monosubstituted (Fcb1) and disubstituted (Fcb2) by bipyridyl groups emphasized the beneficial “sandwich” effect on the recognition behavior of ferrocene-based receptors. Polymer films coated onto electrodes surfaces by electropolymerization of pyrrole-substituted Fcc3 and Fcb2 retained the complexation and the amperometric properties, studied by cyclic voltammetry, of the molecular receptors. Furthermore, capacity measurements using electrochemical impedance spectroscopy (EIS) appeared as a good method for detection and titration of metal cations with these polymer-modified electrodes.

The electrochemical behavior of the pyrrole-substituted crown ether ferrocene 1 was investigated in detail in 0.1 M TBAP+CH 3 CN by cyclic voltammetry (CV) and chronoamperometry. In the potential range 0–0.7 V, a reversible diffusion-controlled process was observed with a formal potential of 0.53 V corresponding to the ferrocene/ferricinium redox couple. Electro-oxidative polymerization of 1 was accomplished either by repeated CV scans, or by controlled potential electrolysis. The resulting polymer films were tested in acetonitrile electrolyte for the amperometric recognition of alkali and alkaline earth metal cations. Their remarkable recognition properties towards Ca 2+ and Ba 2+ cations have been confirmed by electrochemical impedance spectroscopy (EIS). EIS allowed construction of a calibration curve based on the variation of the low frequency capacity of the film as a function of the guest cation concentration, reflecting the variation of the formal potential between the free and the complexed immobilized redox couple. Capacity measurements using EIS appear to be an attractive method for cation sensing with films based on molecular redox receptors.

It is clear from epidemiological studies that excess iron is associated with increased risk of colorectal cancer; however, questions regarding the mechanism of how iron increases cancer risk, the source of the excess iron (circulating or luminal), and whether iron reduction represents a potential therapeutic option remain unanswered. In this study, we show that after Apc deletion, the cellular iron acquisition proteins TfR1 and DMT1 are rapidly induced. Conversely, restoration of APC reduces cellular iron due to repression of these proteins. To test the functional importance of these findings, we performed in vivo investigations of the impact of iron levels on intestinal tumorigenesis. Strikingly, depletion of luminal (but not systemic) iron strongly suppressed murine intestinal tumorigenesis, whereas increased luminal iron strongly promoted tumorigenesis. Taken together, our data definitively delineate iron as a potent modifier of intestinal tumorigenesis and have important implications for dietary iron supplementation in patients at high risk of colorectal cancer.