Journal of Drug Delivery Science and Technology, 2020
Indomethacin (INDO) demonstrates therapeutic efficacy in the treatment of neuroinflammatory disea... more Indomethacin (INDO) demonstrates therapeutic efficacy in the treatment of neuroinflammatory diseases. Despite its importance as a drug, INDO causes gastrointestinal problems and adverse reactions in the central nervous system (CNS). In this study, we prepared nanoparticles of layered double hydroxide (LDH) loaded with INDO. The structure of the nanohybrid (LDH-INDO) was synthesized via a coprecipitation method, and the nanohybrid was characterized using X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis–differential scanning colorimetry (TGA–DSC), field-emission scanning electron microscopy (FE-SEM), and ultraviolet (UV)–vis spectroscopy. Moreover, the drug release profiles of the nanohybrid were investigated using kinetic models. INDO was incorporated within the LDH interlayer space with 50% intercalation. The release of INDO anions from LDH-INDO after 10 h was 90% at pH 4.8 ± 0.02 and 5 1 % at pH 7.4 ± 0.02. The results show...
Geopolymers synthetized from the reaction of metakaolin (or alumino-silicate) in an alkali medium... more Geopolymers synthetized from the reaction of metakaolin (or alumino-silicate) in an alkali medium are studied since decades [1]. However, in order to develop composites, alkali medium is undesirable due to the detrimental effect of alkali ions on fibers. As an alternative, the use of an acid medium seems promising as some authors demonstrated an increase of mechanical properties with acid-based geopolymers [2, 3]. The aim of this work is to investigate the various formulations and to understand the reactional mechanisms.
There is growing interest in using Hollow-core photonic crystal fiber (HC-PCF) in atomic based la... more There is growing interest in using Hollow-core photonic crystal fiber (HC-PCF) in atomic based laser metrology and quantum optics [1]. Atom-filled HC-PCF represents a compact atomic vapour cell, which thanks to its long light-matter interaction distance enhances spectroscopic feature contrasts and optical nonlinearities. These advantages make atom-filled HC-PCF an outstanding candidate for numerous applications such as miniature atomic clocks, magnetometers, single photon sources, Rydberg-blockade based NOT gates, atom-light entanglement etc [1-4]. Furthermore, the small geometric core size of HC-PCF (5 to 100 μm) and large inner wall surface volume enhance atom-surface effects like physicochemical processes, surface material adsorption, Van der Waals (VW) interaction and Casimir Polder forces, which play a significant role in spectroscopic features that strongly differ from the conventional macroscopic vapor cells. Here we report on experimental observation of wall surface induced ...
Materials such as ceramic matrix composites are developed for mechanical applications at high tem... more Materials such as ceramic matrix composites are developed for mechanical applications at high temperature, but their cost remains a limitation. Consequently, the use of acid-based geopolymer matrices may be an alternative to reduce costs. In this study, the sample was prepared from metakaolin and phosphoric acid. Fourier Transform InfraRed and Nuclear Magnetic Resonance spectroscopies, X-Ray Diffraction and thermal measurements were used to understand the structural evolution of acid-based geopolymers (binders) during consolidation and after thermal treatments. According to the results, the consolidation of the binder has been divided into four steps: the dissolution of the metakaolin, the polycondensation reactions forming AlPO4 entities and hydrated phases, the breakdown of SiOAl bonds with formation of various hydrated silica networks and finally the completion of the networks. After a thermal treatment at 1000 °C, the binder consists of AlPO4 phases, quartz and vitreous silica.
Abstract Two metakaolins exhibiting different reactivities were used to study geopolymers obtaine... more Abstract Two metakaolins exhibiting different reactivities were used to study geopolymers obtained via phosphoric acid activation. The study of consolidation of samples with various Si/Al and Al/P showed that the Al- and Si-rich and P-poor compositions were more likely to consolidate properly. The geopolymers formed at 20 or 70 °C kept the same crystalline impurities as the starting metakaolins, the samples remaining mostly amorphous. The microstructure of geopolymers formed with less reactive metakaolin was smooth and dense, while the geopolymers prepared from the most reactive one were more porous and rough. Finally, tests on water and fire resistances of all the samples were reported.
Journal of Drug Delivery Science and Technology, 2020
Indomethacin (INDO) demonstrates therapeutic efficacy in the treatment of neuroinflammatory disea... more Indomethacin (INDO) demonstrates therapeutic efficacy in the treatment of neuroinflammatory diseases. Despite its importance as a drug, INDO causes gastrointestinal problems and adverse reactions in the central nervous system (CNS). In this study, we prepared nanoparticles of layered double hydroxide (LDH) loaded with INDO. The structure of the nanohybrid (LDH-INDO) was synthesized via a coprecipitation method, and the nanohybrid was characterized using X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis–differential scanning colorimetry (TGA–DSC), field-emission scanning electron microscopy (FE-SEM), and ultraviolet (UV)–vis spectroscopy. Moreover, the drug release profiles of the nanohybrid were investigated using kinetic models. INDO was incorporated within the LDH interlayer space with 50% intercalation. The release of INDO anions from LDH-INDO after 10 h was 90% at pH 4.8 ± 0.02 and 5 1 % at pH 7.4 ± 0.02. The results show...
Geopolymers synthetized from the reaction of metakaolin (or alumino-silicate) in an alkali medium... more Geopolymers synthetized from the reaction of metakaolin (or alumino-silicate) in an alkali medium are studied since decades [1]. However, in order to develop composites, alkali medium is undesirable due to the detrimental effect of alkali ions on fibers. As an alternative, the use of an acid medium seems promising as some authors demonstrated an increase of mechanical properties with acid-based geopolymers [2, 3]. The aim of this work is to investigate the various formulations and to understand the reactional mechanisms.
There is growing interest in using Hollow-core photonic crystal fiber (HC-PCF) in atomic based la... more There is growing interest in using Hollow-core photonic crystal fiber (HC-PCF) in atomic based laser metrology and quantum optics [1]. Atom-filled HC-PCF represents a compact atomic vapour cell, which thanks to its long light-matter interaction distance enhances spectroscopic feature contrasts and optical nonlinearities. These advantages make atom-filled HC-PCF an outstanding candidate for numerous applications such as miniature atomic clocks, magnetometers, single photon sources, Rydberg-blockade based NOT gates, atom-light entanglement etc [1-4]. Furthermore, the small geometric core size of HC-PCF (5 to 100 μm) and large inner wall surface volume enhance atom-surface effects like physicochemical processes, surface material adsorption, Van der Waals (VW) interaction and Casimir Polder forces, which play a significant role in spectroscopic features that strongly differ from the conventional macroscopic vapor cells. Here we report on experimental observation of wall surface induced ...
Materials such as ceramic matrix composites are developed for mechanical applications at high tem... more Materials such as ceramic matrix composites are developed for mechanical applications at high temperature, but their cost remains a limitation. Consequently, the use of acid-based geopolymer matrices may be an alternative to reduce costs. In this study, the sample was prepared from metakaolin and phosphoric acid. Fourier Transform InfraRed and Nuclear Magnetic Resonance spectroscopies, X-Ray Diffraction and thermal measurements were used to understand the structural evolution of acid-based geopolymers (binders) during consolidation and after thermal treatments. According to the results, the consolidation of the binder has been divided into four steps: the dissolution of the metakaolin, the polycondensation reactions forming AlPO4 entities and hydrated phases, the breakdown of SiOAl bonds with formation of various hydrated silica networks and finally the completion of the networks. After a thermal treatment at 1000 °C, the binder consists of AlPO4 phases, quartz and vitreous silica.
Abstract Two metakaolins exhibiting different reactivities were used to study geopolymers obtaine... more Abstract Two metakaolins exhibiting different reactivities were used to study geopolymers obtained via phosphoric acid activation. The study of consolidation of samples with various Si/Al and Al/P showed that the Al- and Si-rich and P-poor compositions were more likely to consolidate properly. The geopolymers formed at 20 or 70 °C kept the same crystalline impurities as the starting metakaolins, the samples remaining mostly amorphous. The microstructure of geopolymers formed with less reactive metakaolin was smooth and dense, while the geopolymers prepared from the most reactive one were more porous and rough. Finally, tests on water and fire resistances of all the samples were reported.
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Papers by Jenny Jouin