Jenny Jouin - Academia.edu (original) (raw)

Papers by Jenny Jouin

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...

A series of iron-and/or aluminium-doped apatite-type lanthanum silicates (ATLS) La 10-x Si 6-y-z ... more A series of iron-and/or aluminium-doped apatite-type lanthanum silicates (ATLS) La 10-x Si 6-y-z Al y Fe z O 27-3x/2-(y+z)/2 (x = 0.17; y = 0, 0.25, 0.75, 1.5; z = 0, 0.25, 0.75, 1.5) were synthesized using the mechanochemical activation (MA), solid state reaction (SSR), Pechini (Pe), sol-gel (SG) and combustion methods. The total conductivity of the prepared materials was measured under air in the temperature range 600-850 ο C using 4-probe AC impedance spectroscopy. Its depencence on composition, synthesis method, sintering conditions and powder particle size was investigated. It was found that for electrolytes of the same composition, those prepared via mechanochemical activation exhibited the highest conductivity, which was improved with increasing Al-and decreasing Fe-content. The highest conductivity value at 700 o C, equal to 2.04 x 10-2 S cm-1 , was observed for the La 9.83 Si 5 Al 0.75 Fe 0.25 O 26.25 electrolyte. The electrochemical characteristics of a La 0.8 Sr 0.2 Ni 0.4 Fe 0.6 O 3 cathode electrode interfaced to La 9.83 Si 5 Al 0.75 Fe 0.25 O 26.25 apatite-type electrolyte were studied using AC impedance spectroscopy under open circuit conditions, at temperatures 600 to 800 o C and oxygen partial pressures in the range 0.1 to 20 kPa. The cathode and electrolyte powders were prepared via the Pechini method and the mechanochemical activation method, respectively. The electrocatalytic activity of the tested interface was assessed on the basis of its open circuit area specific polarization

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.

Nanocrystalline InN powders have been synthesized through metal azide decomposition in superheate... more Nanocrystalline InN powders have been synthesized through metal azide decomposition in superheated toluene and refluxing hexadecane solvents near 280 °C. The metal azide intermediates were formed in situ through the metathesis reaction of InBr 3 and NaN 3. The InN products from toluene consist of ~10 nm hexagonal (wurtzite) structured crystallites in aggregated arrangements. InN from hexadecane and lower temperature toluene reactions produced more poorly crystalline InN that appears to contain a cubic (zinc blende) component. Coordinating amine solvents led to decomposition of the nitride to indium metal. Several reactions were undertaken to produce mixed metal nitrides of the form Ga 1-z In z N where z is 0.5 and 0.75. The mixed metal nitride products are analytically consistent with composite versus solid-solution formation, however some metal mixing is observed. Data from Xray diffraction, electron microscopy, thermal analysis, elemental analysis, and several spectroscopic methods are combined to form a consistent picture of the bulk and surface structures for these nanocrystalline InN materials.

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 ...

Acta Crystallographica Section A Foundations and Advances, 2015

n the present study, we report for the first time the synthesis of ultra small PbS nanorods in a ... more n the present study, we report for the first time the synthesis of ultra small PbS nanorods in a non-ionic sugar based water-in-oil (w/o) microemulsion system using food grade sucrose ester as surfactant. PbS was formed by mixing lead nitrate and thioacetamide in the water core of the microemulsion system. The as-prepared PbS nanorods were characterized by Xray diffractometry (XRD), uv-visible absorption spectroscopy (UV-VIS), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The diameter of the PbS nanorods were found to be extremely small, which is in the range of 2.64 nm to 2.91 nm depending on reaction aging time. Spherical PbS nanoparticles were formed after 12 h and PbS nanorods were formed after more than 1 day of reaction aging time.

Journal of Non-Crystalline Solids

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.

Journal of Non-Crystalline Solids

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...

A series of iron-and/or aluminium-doped apatite-type lanthanum silicates (ATLS) La 10-x Si 6-y-z ... more A series of iron-and/or aluminium-doped apatite-type lanthanum silicates (ATLS) La 10-x Si 6-y-z Al y Fe z O 27-3x/2-(y+z)/2 (x = 0.17; y = 0, 0.25, 0.75, 1.5; z = 0, 0.25, 0.75, 1.5) were synthesized using the mechanochemical activation (MA), solid state reaction (SSR), Pechini (Pe), sol-gel (SG) and combustion methods. The total conductivity of the prepared materials was measured under air in the temperature range 600-850 ο C using 4-probe AC impedance spectroscopy. Its depencence on composition, synthesis method, sintering conditions and powder particle size was investigated. It was found that for electrolytes of the same composition, those prepared via mechanochemical activation exhibited the highest conductivity, which was improved with increasing Al-and decreasing Fe-content. The highest conductivity value at 700 o C, equal to 2.04 x 10-2 S cm-1 , was observed for the La 9.83 Si 5 Al 0.75 Fe 0.25 O 26.25 electrolyte. The electrochemical characteristics of a La 0.8 Sr 0.2 Ni 0.4 Fe 0.6 O 3 cathode electrode interfaced to La 9.83 Si 5 Al 0.75 Fe 0.25 O 26.25 apatite-type electrolyte were studied using AC impedance spectroscopy under open circuit conditions, at temperatures 600 to 800 o C and oxygen partial pressures in the range 0.1 to 20 kPa. The cathode and electrolyte powders were prepared via the Pechini method and the mechanochemical activation method, respectively. The electrocatalytic activity of the tested interface was assessed on the basis of its open circuit area specific polarization

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.

Nanocrystalline InN powders have been synthesized through metal azide decomposition in superheate... more Nanocrystalline InN powders have been synthesized through metal azide decomposition in superheated toluene and refluxing hexadecane solvents near 280 °C. The metal azide intermediates were formed in situ through the metathesis reaction of InBr 3 and NaN 3. The InN products from toluene consist of ~10 nm hexagonal (wurtzite) structured crystallites in aggregated arrangements. InN from hexadecane and lower temperature toluene reactions produced more poorly crystalline InN that appears to contain a cubic (zinc blende) component. Coordinating amine solvents led to decomposition of the nitride to indium metal. Several reactions were undertaken to produce mixed metal nitrides of the form Ga 1-z In z N where z is 0.5 and 0.75. The mixed metal nitride products are analytically consistent with composite versus solid-solution formation, however some metal mixing is observed. Data from Xray diffraction, electron microscopy, thermal analysis, elemental analysis, and several spectroscopic methods are combined to form a consistent picture of the bulk and surface structures for these nanocrystalline InN materials.

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 ...

Acta Crystallographica Section A Foundations and Advances, 2015

n the present study, we report for the first time the synthesis of ultra small PbS nanorods in a ... more n the present study, we report for the first time the synthesis of ultra small PbS nanorods in a non-ionic sugar based water-in-oil (w/o) microemulsion system using food grade sucrose ester as surfactant. PbS was formed by mixing lead nitrate and thioacetamide in the water core of the microemulsion system. The as-prepared PbS nanorods were characterized by Xray diffractometry (XRD), uv-visible absorption spectroscopy (UV-VIS), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The diameter of the PbS nanorods were found to be extremely small, which is in the range of 2.64 nm to 2.91 nm depending on reaction aging time. Spherical PbS nanoparticles were formed after 12 h and PbS nanorods were formed after more than 1 day of reaction aging time.

Journal of Non-Crystalline Solids

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.

Journal of Non-Crystalline Solids

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.