P. Caillet

Bio: P. Caillet is an academic researcher. The author has contributed to research in topics: Humanities & Political science. The author has an hindex of 1, co-authored 1 publications receiving 31 citations.

(Dé)prescription des inhibiteurs de la pompe à protons : quelle évolution ces dernière années ? Étude régionale à partir de la base de données de l’Assurance Maladie

Abstract: Les inhibiteurs de la pompe à protons (IPP) sont très largement utilisés, et leur consommation est croissante depuis plusieurs années malgré des recommandations de diminution de leur utilisation. Afin d’évaluer l’impact d’interventions de déprescription, il est indispensable de connaître précisément l’évolution naturelle des consommations dans la population étudiée. Ces données n’étant pas décrites en région PDL (Pays-de-la-Loire), une étude pharmacoépidémiologique a été conduite, associant pharmaciens hospitaliers et médecins de l’Assurance Maladie. Les objectifs étaient d’évaluer l’évolution naturelle des consommations chroniques d’IPP dispensés en ville et leur taux de déprescription, décrire l’évolution de l’incidence et de la prévalence de consommation des IPP et les caractéristiques des prescripteurs. Il s’agissait d’une étude de cohorte historique à partir des bases de données du Système national des données de santé (SNDS). L’ensemble des patients adultes vivant en région PDL, couverts par l’Assurance Maladie, et ayant eu au moins un remboursement pour une délivrance d’IPP entre le 1er octobre 2016 et le 31 décembre 2020 ont été inclus. Seuls les patients consommateurs chroniques ont été retenus, c’est-à-dire ceux pour lesquels une dispensation avait eu lieu sur les 3 derniers mois de l’année passée. Une déprescription était définie par une absence de remboursement durant les deux derniers mois de l’année en cours. Le nombre de patients consommateurs chroniques incidents a augmenté régulièrement en passant de 46 308 en 2017 à 77 222 en 2020 soit un taux d’incidence augmentant de 1,2 % à 2 % par rapport à la population générale de la région. Le nombre de patients consommateurs chroniques prévalents a augmenté de 156 721 en 2017 à 167 751 en 2020 soit de 4,1 % à 4,4 %. Le pourcentage d’arrêt du traitement chronique en 2017 était de 12,47 % et de 12,37 % en 2020. En 2020, 87,1 % (67 280) des traitements chroniques par IPP ont été initiés par des médecins généralistes, 9820 (12,7 %) par des médecins d’établissement de santé et 122 (0,2 %) par d’autres spécialités médicales. Ces résultats montrent une stagnation du processus de déprescription naturelle des IPP ces 4 dernières années, ainsi que le rôle prépondérant des médecins généralistes dans leur prescription. Cela renforce l’intérêt de la mise en place d’un projet de déprescription et permet de connaître les données initiales d’un potentiel bras contrôle. Une étude sur l’impact de la déprescription des IPP et de son maintien au long cours pourrait permettre d’évaluer l’implication des pharmaciens cliniciens dans cette activité.

Soot oxidation catalyzed by a Cu/K/Mo/Cl catalyst: evaluation of the chemistry and performance of the catalyst

Abstract: Several non-supported oxidic compounds potentially present in a Cu/K/Mo/Cl catalyst (copper molybdates, potassium molybdates, and a mixed copper-potassium molybdate (K2Cu2(MoO4)3)) have been tested individually on their activity in the oxidation of a model soot (Printex-U, which non-catalytically oxidizes at 875 K). These oxidic compounds are active between 665 and 720 K, but only after establishment of ‘tight contact’ between the catalyst and soot in a ball mill. Without the ball mill procedure (‘loose contact’) these oxides are less active (the soot oxidation temperature is shifted to about 790 K), while a ZrO2 supported Cu/K/Mo/Cl catalyst still shows a high activity around 670 K. Hence, the ‘loose contact’ activity of the supported Cu/K/Mo/Cl catalyst is not explained by the presence of an active oxidic compound. DRIFT and XRD analyses have shown that addition of KCl to CuMoO4 (two compounds present within the Cu/K/Mo/Cl catalysts) followed by calcination at 950 K in air, eventually results in the formation of a mixed potassium-copper molybdate. Simultaneously several volatile copper, potassium and chlorine containing compounds (e.g. K2CuCl4) are formed. These copper and chlorine containing compounds possess a high ‘loose contact’ soot oxidation activity between 600 and 690 K. A catalytic cycle, involving Cu2OCl2, is proposed to explain the high ‘loose contact’ activity of copper chlorides and supported Cu/K/Mo/Cl catalysts. The activity of the latter catalyst will be maintained as long as Cu2OCl2 can be reformed by reaction of copper molybdates with KCl, which serves as a chlorine supplier.

Structural study of WO3TeO2 glasses

Abstract: Raman spectra of WO3TeO2 glasses and tungstate crystals were investigated. Properties of the glasses such as transition temperature, thermal expansion and density were measured. In the glasses, most tellurium atoms form TeO4 trigonal bipyramids and WO bonds are present. The glasses contain clusters composed of corner-shared WO6 octahedra. An increase in WO3 content promotes the growth of clusters. The coordination state of W6+ having a WO bond is discussed on the basis of crystal chemistry. Tungsten coordination polyhedra occupying the interface of the cluster have a WO bond.

Self-Assembled NiWO4 Nanoparticles into Chain-like Aggregates on DNA Scaffold with Pronounced Catalytic and Supercapacitor Activities

Abstract: We report a new route for the self-assembled NiWO4 nanoparticles (NPs) in chain-like aggregates on a DNA scaffold by the reaction of nickel(II) acetate with sodium tungstate under continuous stirring and heating at 60 °C within 90 min of reaction. The size of the individual NiWO4 particles was found to be ∼20–30 nm and the diameter of the aggregates was in the ∼220 ± 30 nm range. The probable growth mechanisms of DNA–NiWO4 chain-like aggregates were elaborated. The potential of the NiWO4 chain-like aggregates was tested in catalytic reaction and in electrochemical supercapacitor studies. Catalysis study revealed that the NiWO4 aggregated structure acts as a suitable catalyst for the conversion of K3[Fe(CN)6] to K4[Fe(CN)6] in the presence of Na2S2O3 under UV-light illumination within a short time. Supercapacitor study signified that different morphologies of NiWO4 show different specific capacitance (C) values, and the highest C value of 173 F g–1 at a scan rate of 5 mV s–1 was observed while chain diamet...

Unprecedented high photocatalytic activity of nanocrystalline WO3/NiWO4 hetero-junction towards dye degradation: Effect of template and synthesis conditions

Abstract: Nanocrystalline NiWO4 wolframite structure has been prepared by a simple salt solution addition (NiW1SS), co-precipitation (NiW4Cop) and sol–gel (NiW4SG) techniques via employing polymeric templates particularly polyethylene glycol (PEG) and triblock copolymer, respectively. The synthesis method as well as the metal molar ratio (W/Ni) influenced the phases, morphology, optical and surface properties of synthesized samples as configured by X-ray diffraction, transmission electron microscopy, UV–vis diffuse reflectance spectroscopy, infrared spectroscopy, X-ray photoelectron spectroscopy and N2 sorptiometry techniques. Accordingly, the NiW1SS material that exposed only NiWO4 of nano-plate shape at a molar ratio (W/Ni) 1 indicates higher surface texturing values (SBET = 52.6 m2/g, Vp = 0.2061 cm3/g and r = 15.7 nm) exceeding those of NiW4Cop (SBET = 15.07 m2/g, Vp = 0.0491 cm3/g and r = 13.0 nm) of anisotropic shapes (hexagonal and tetragonal); synthesized at a ratio of 4 and by the same template (PEG). The NiW1SS material indicated Eg value of 2.23 eV whereas that of NiW4Cop revealed a value of 2.92 eV. On the other hand, NiW4SG that exposed well crystallized WO3 beside NiWO4 of nano-flakes shape and an average diameter of 25 nm indicates Eg value of 2.56 eV and in addition evokes the formation of narrow pore size distribution in mesopores range (2–12 nm) as well as in macropores (60 nm) exploring the effect of template type on the pore texturing. Photodegradation of methylene blue (MB) dye was used to evaluate the photoactivity of NiWO4 catalysts under UV irradiations. The NiW4SG catalyst exhibited the best degradation performance (92.5% for MB after 5 h). The results showed that the feasibility of MB degradation was not only due to morphological properties but also to the NiWO4/WO3 heterojunction. Significantly, WO3 facilitates effective charge separation as traced by the photoluminescence emission spectra.

Direct Mechanochemical Synthesis of Nanocrystalline NiWO4

Abstract: The possibilities of mechanochemical activation as a successful route for direct synthesis of NiWO4 have been studied. A stoichiometric mixture of NiO and WO3 in a 1:1 molar ratio was subjected to intense mechanical treatment in air using a planetary ball mill for different periods of time. The phase and structural transformations were monitored by X-ray diffraction (XRD), infrared spectroscopy (IR), and X-ray photoelectron spectroscopy (XPS). It was found that 7.5 h of milling of the reagents leads to complete crystallization of single nanostructured phase NiWO4 at room temperature.