Gérard Meunier - Academia.edu (original) (raw)

Papers by Gérard Meunier

Research paper thumbnail of Selected papers from the 7th International Symposium on Medical Geography. Portsmouth, United Kingdom

Social science & medicine (1982), 1998

Research paper thumbnail of Numerical prediction of long-term stability of liquid formulations determined by visual observation and static multiple light scattering

Colloids and Surfaces A: Physicochemical and Engineering Aspects, Apr 1, 2023

Research paper thumbnail of Phase transitions in polymorphic materials probed using space-resolved diffusing wave spectroscopy

Soft Matter, 2018

We demonstrate light scattering as a new non-invasive, contactless method to detect polymorphic p... more We demonstrate light scattering as a new non-invasive, contactless method to detect polymorphic phase transitions in soft matter.

Research paper thumbnail of Physical stability of nanoparticle dispersion

TechConnect Briefs, Jun 13, 2011

Research paper thumbnail of Passive Microrheology : Non Intrusive Measurement to Follow Viscoelastic Evolution and Concentration Effects

Research paper thumbnail of Prediction of collapse time of polymer stabilized O/W emulsions

Research paper thumbnail of Passive Microrheology : Contact Free Method for Viscoelastic Properties Measurement and Structural Analysis of Polymers and Materials

Research paper thumbnail of Characterizing dispersions throughout the oil industry: comprehensive formulation analysis

Research paper thumbnail of Predicting the long-term stability of depletion-flocculated emulsions by static multiple light scattering (SMLS)

Journal of Dispersion Science and Technology, May 13, 2019

Abstract Predicting the gravitational stability of weakly flocculated colloidal dispersions is a ... more Abstract Predicting the gravitational stability of weakly flocculated colloidal dispersions is a key problem in product formulation. For these systems, destabilization can occur suddenly after several months of apparent stability. During this time there are no visible signs of imminent collapse. We show that the intensity of backscattered light changes slowly during the period of apparent stability, and that its rate of change at short times correlates with the time when the system collapses, the stability time. Collapse occurred as sedimentation for weak gels, but as syneresis for stronger gels, presumably because the gravitational stress was less than the yield stress in the latter cases. The light spot backscattered from a point source by a turbid colloidal dispersion has a universal shape. In general, its size depends on only one parameter: the mean photon transport length, l*. An optical scanner was used to measure simultaneously the stability time and l* for an emulsion stabilized by a range of concentrations of three polymers. It was found that the stability time correlates with the rate of change of l* after 1 day, up to visual stability times exceeding 1000 days. This correlation can be understood by the relationship between l* and the static structure factor. Several previous studies have shown that the static structure factor increases at small scattering angles during the stability time. The correlation can form the basis of a method to predict the stability time of weakly flocculated dispersions. GRAPHICAL ABSTRACT

Research paper thumbnail of Film formation analysis by diffusive wave spectroscopy

Progress in Organic Coatings, Mar 1, 2009

Research paper thumbnail of Passive Microrheology for Measurement of the Concentrated Dispersions Stability

Springer eBooks, 2012

This work presents a new technique of passive microrheology for the study of the microstructural ... more This work presents a new technique of passive microrheology for the study of the microstructural properties of soft materials such as emulsions or suspensions. This technology uses Multi Speckle Diffusing Wave Spectroscopy (MS-DWS) set-up in a backscattering configuration with video camera detection. It measures the mean displacement of the microstructure particles in a spatial range between 0.1 and 100 nm and a time scale between 10−2 and 105 s. Different parameters can be measured or obtained directly from the Mean Square Displacement (MSD) curve, including a fluidity index, a solid–liquid balance, an elasticity index, a viscosity index, a relaxation time and a MSD slope.

Research paper thumbnail of Passive Microrheology : Non Contact Measurement of Viscoelastic Properties of Biopolymers

TechConnect Briefs, Jun 13, 2011

Research paper thumbnail of Particle Size and Rapid Stability Analyses of Concentrated Dispersions: Use of Multiple Light Scattering Technique

Acs Symposium Series, Jun 25, 2004

Research paper thumbnail of Quantitative physical stability analysis of concentrated, fragrance-infused liquid fabric care dispersions

INFORM International News on Fats, Oils, and Related Materials, 2018

Research paper thumbnail of Space-resolved diffusing wave spectroscopy measurements of the macroscopic deformation and the microscopic dynamics in tensile strain tests

Optics and Lasers in Engineering, 2017

Research paper thumbnail of Method and Apparatus for Analysing the Phases of a Multi-Phase Mixture

Research paper thumbnail of Caractérisation optique de l'instabilité des dispersions concentrées

Les Cahiers De Rheologie, 1998

Research paper thumbnail of Multiple Light Scattering Methods for Dispersion Characterization and Control of Particulate Processes

ACS Symposium Series, 2004

ABSTRACT This work concerns multiple light scattering methods for the characterization of concent... more ABSTRACT This work concerns multiple light scattering methods for the characterization of concentrated dispersions. After recall of the wave transport theory and some experimental means for analyzing incoherent wave propagation in heterogeneous media, the present paper concerns a new imagery method for the optical characterization of concentrated dispersions and applications in the field of industrial processes.

Research paper thumbnail of Passive Microrheology for Measurement of the Concentrated Dispersions Stability

UK Colloids 2011, 2012

This work presents a new technique of passive microrheology for the study of the microstructural ... more This work presents a new technique of passive microrheology for the study of the microstructural properties of soft materials such as emulsions or suspensions. This technology uses Multi Speckle Diffusing Wave Spectroscopy (MS-DWS) set-up in a backscattering configuration with video camera detection. It measures the mean displacement of the microstructure particles in a spatial range between 0.1 and 100 nm and a time scale between 10−2 and 105 s. Different parameters can be measured or obtained directly from the Mean Square Displacement (MSD) curve, including a fluidity index, a solid–liquid balance, an elasticity index, a viscosity index, a relaxation time and a MSD slope.

Research paper thumbnail of o-Quinone formation in the biochemical oxidation of the antitumor drug N2-methyl-9-hydroxyellipticinium acetate

Journal of Medicinal Chemistry, 1983

The activation of N2-methyl-9-hydroxyellipticinium acetate (4) by a peroxidase--H2O2 system leads... more The activation of N2-methyl-9-hydroxyellipticinium acetate (4) by a peroxidase--H2O2 system leads to the formation of an omicron-quinone (7a). This omicron-quinone is not directly generated from the starting material but through a quinone imine intermediate (6) which is subsequently oxidized. This reaction is highly dependent on pH values. The omicron-quinone 7a is easily protonated (7b), gives an addition product with methanol (9), and is reduced by cysteine. The omicron-quinone 7b has a rather low inhibitory effect against L1210 leukemia cell multiplication but acts as an electron carrier and dramatically augments the oxygen consumption in xanthine oxidase-NADH and rat liver microsomes-NADPH systems.

Research paper thumbnail of Selected papers from the 7th International Symposium on Medical Geography. Portsmouth, United Kingdom

Social science & medicine (1982), 1998

Research paper thumbnail of Numerical prediction of long-term stability of liquid formulations determined by visual observation and static multiple light scattering

Colloids and Surfaces A: Physicochemical and Engineering Aspects, Apr 1, 2023

Research paper thumbnail of Phase transitions in polymorphic materials probed using space-resolved diffusing wave spectroscopy

Soft Matter, 2018

We demonstrate light scattering as a new non-invasive, contactless method to detect polymorphic p... more We demonstrate light scattering as a new non-invasive, contactless method to detect polymorphic phase transitions in soft matter.

Research paper thumbnail of Physical stability of nanoparticle dispersion

TechConnect Briefs, Jun 13, 2011

Research paper thumbnail of Passive Microrheology : Non Intrusive Measurement to Follow Viscoelastic Evolution and Concentration Effects

Research paper thumbnail of Prediction of collapse time of polymer stabilized O/W emulsions

Research paper thumbnail of Passive Microrheology : Contact Free Method for Viscoelastic Properties Measurement and Structural Analysis of Polymers and Materials

Research paper thumbnail of Characterizing dispersions throughout the oil industry: comprehensive formulation analysis

Research paper thumbnail of Predicting the long-term stability of depletion-flocculated emulsions by static multiple light scattering (SMLS)

Journal of Dispersion Science and Technology, May 13, 2019

Abstract Predicting the gravitational stability of weakly flocculated colloidal dispersions is a ... more Abstract Predicting the gravitational stability of weakly flocculated colloidal dispersions is a key problem in product formulation. For these systems, destabilization can occur suddenly after several months of apparent stability. During this time there are no visible signs of imminent collapse. We show that the intensity of backscattered light changes slowly during the period of apparent stability, and that its rate of change at short times correlates with the time when the system collapses, the stability time. Collapse occurred as sedimentation for weak gels, but as syneresis for stronger gels, presumably because the gravitational stress was less than the yield stress in the latter cases. The light spot backscattered from a point source by a turbid colloidal dispersion has a universal shape. In general, its size depends on only one parameter: the mean photon transport length, l*. An optical scanner was used to measure simultaneously the stability time and l* for an emulsion stabilized by a range of concentrations of three polymers. It was found that the stability time correlates with the rate of change of l* after 1 day, up to visual stability times exceeding 1000 days. This correlation can be understood by the relationship between l* and the static structure factor. Several previous studies have shown that the static structure factor increases at small scattering angles during the stability time. The correlation can form the basis of a method to predict the stability time of weakly flocculated dispersions. GRAPHICAL ABSTRACT

Research paper thumbnail of Film formation analysis by diffusive wave spectroscopy

Progress in Organic Coatings, Mar 1, 2009

Research paper thumbnail of Passive Microrheology for Measurement of the Concentrated Dispersions Stability

Springer eBooks, 2012

This work presents a new technique of passive microrheology for the study of the microstructural ... more This work presents a new technique of passive microrheology for the study of the microstructural properties of soft materials such as emulsions or suspensions. This technology uses Multi Speckle Diffusing Wave Spectroscopy (MS-DWS) set-up in a backscattering configuration with video camera detection. It measures the mean displacement of the microstructure particles in a spatial range between 0.1 and 100 nm and a time scale between 10−2 and 105 s. Different parameters can be measured or obtained directly from the Mean Square Displacement (MSD) curve, including a fluidity index, a solid–liquid balance, an elasticity index, a viscosity index, a relaxation time and a MSD slope.

Research paper thumbnail of Passive Microrheology : Non Contact Measurement of Viscoelastic Properties of Biopolymers

TechConnect Briefs, Jun 13, 2011

Research paper thumbnail of Particle Size and Rapid Stability Analyses of Concentrated Dispersions: Use of Multiple Light Scattering Technique

Acs Symposium Series, Jun 25, 2004

Research paper thumbnail of Quantitative physical stability analysis of concentrated, fragrance-infused liquid fabric care dispersions

INFORM International News on Fats, Oils, and Related Materials, 2018

Research paper thumbnail of Space-resolved diffusing wave spectroscopy measurements of the macroscopic deformation and the microscopic dynamics in tensile strain tests

Optics and Lasers in Engineering, 2017

Research paper thumbnail of Method and Apparatus for Analysing the Phases of a Multi-Phase Mixture

Research paper thumbnail of Caractérisation optique de l'instabilité des dispersions concentrées

Les Cahiers De Rheologie, 1998

Research paper thumbnail of Multiple Light Scattering Methods for Dispersion Characterization and Control of Particulate Processes

ACS Symposium Series, 2004

ABSTRACT This work concerns multiple light scattering methods for the characterization of concent... more ABSTRACT This work concerns multiple light scattering methods for the characterization of concentrated dispersions. After recall of the wave transport theory and some experimental means for analyzing incoherent wave propagation in heterogeneous media, the present paper concerns a new imagery method for the optical characterization of concentrated dispersions and applications in the field of industrial processes.

Research paper thumbnail of Passive Microrheology for Measurement of the Concentrated Dispersions Stability

UK Colloids 2011, 2012

This work presents a new technique of passive microrheology for the study of the microstructural ... more This work presents a new technique of passive microrheology for the study of the microstructural properties of soft materials such as emulsions or suspensions. This technology uses Multi Speckle Diffusing Wave Spectroscopy (MS-DWS) set-up in a backscattering configuration with video camera detection. It measures the mean displacement of the microstructure particles in a spatial range between 0.1 and 100 nm and a time scale between 10−2 and 105 s. Different parameters can be measured or obtained directly from the Mean Square Displacement (MSD) curve, including a fluidity index, a solid–liquid balance, an elasticity index, a viscosity index, a relaxation time and a MSD slope.

Research paper thumbnail of o-Quinone formation in the biochemical oxidation of the antitumor drug N2-methyl-9-hydroxyellipticinium acetate

Journal of Medicinal Chemistry, 1983

The activation of N2-methyl-9-hydroxyellipticinium acetate (4) by a peroxidase--H2O2 system leads... more The activation of N2-methyl-9-hydroxyellipticinium acetate (4) by a peroxidase--H2O2 system leads to the formation of an omicron-quinone (7a). This omicron-quinone is not directly generated from the starting material but through a quinone imine intermediate (6) which is subsequently oxidized. This reaction is highly dependent on pH values. The omicron-quinone 7a is easily protonated (7b), gives an addition product with methanol (9), and is reduced by cysteine. The omicron-quinone 7b has a rather low inhibitory effect against L1210 leukemia cell multiplication but acts as an electron carrier and dramatically augments the oxygen consumption in xanthine oxidase-NADH and rat liver microsomes-NADPH systems.