Didier Perret | University of Geneva, Switzerland (original) (raw)
Papers by Didier Perret
Environmental Particles, 2019
Apparatus for collecting body fluids at an internal cavity of the body of a living being. An encl... more Apparatus for collecting body fluids at an internal cavity of the body of a living being. An enclosure is introduced into a body cavity with the enclosure in a contracted or evacuated condition. The enclosure has structure permitting body fluid to enter into the enclosure but not to flow out of the latter. A suitable triggering structure is provided to respond to the presence of a body fluid in order to trigger the release of the enclosure for collection, whereupon the enclosure sucks body fluid into the interior of the enclosure, with the enclosure having a structure such as a one-way valve which provides conditions permitting the fluid to flow into the enclosure but not to flow out of the latter. Thereafter, the enclosure is removed from the body cavity so that information can be obtained with respect to the fluid which is collected in the enclosure. The enclosure preferably contains an additive for providing a predetermined desired result with respect to a collected body fluid.
CHIMIA International Journal for Chemistry, 2019
Brock/Springer Series in Contemporary Bioscience, 1990
The complexity involved in studying the biogeochemical cycles of particles and colloids in freshw... more The complexity involved in studying the biogeochemical cycles of particles and colloids in freshwaters is the result of several different factors: the great number of appearance and disappearance fluxes of these species, the difficulties associated with distinguishing and measuring those fluxes, and the difficulty of sampling colloidal particles without denaturation before their characterization. On the other hand, information obtained in laboratory studies of synthetic colloids are not always representative of the mechanisms encountered in heterogeneous natural environments. This article, taking autochthonous iron-rich colloids as a model, summarizes the state of the art concerning current knowledge of these colloids and emphasizes the need to develop new techniques specifically oriented towards analysis of natural colloids and their fluxes while taking care to minimize artifacts introduced by presently employed techniques. Finally, as a pertinent illustration, both the problems and the future uses of well-known filtration techniques are considered.
Note: Lawrence Berkeley Lab, Berkeley, CA 94720 USA.Lorusso, GF, Lawrence Berkeley Lab, 1 Cyclotr... more Note: Lawrence Berkeley Lab, Berkeley, CA 94720 USA.Lorusso, GF, Lawrence Berkeley Lab, 1 Cyclotron Rd,MS 2-400, Berkeley, CA 94720 USA.ISI Document Delivery No.: BK48CArticle7th International Symposium on Neutron Capture TherapySEP 04-07, 1996ZURICH, SWITZERLANDSARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS Reference LSE-CHAPTER-1997-004 Record created on 2006-10-03, modified on 2017-05-12
Journal of Microscopy, 2008
Electron energy‐loss spectroscopy (EELS) and elemental imaging under the energy‐filtered transmis... more Electron energy‐loss spectroscopy (EELS) and elemental imaging under the energy‐filtered transmission electron microscope are powerful tools for the characterization of iron‐rich particles present in natural waters. Features present in EEL spectra (Fe‐M2,3 Fe‐L2,3 and O‐K ionization edges) of goethite (α‐FeOOH) have been studied with an energy filter operated at 80 keV to determine optimal quantification and elemental imaging of Fe‐rich natural aquatic particles in the 30–200 nm range of thickness. For quantitative aims, the Fe‐M2,3 ionization edge cannot be used easily, but the Fe‐L2,3 edge provides more accurate results owing to a better background extrapolation. The partial cross‐section of the Fe(III) M shell has been determined for iron oxide. The use of two‐windows (jump‐ratio) and three‐windows (background stripping) imaging methods is discussed in relation to the specimen thickness.
Aquatic Microbial Ecology, 1998
Pas de résumé disponible. PERRET, Didier. Caractéristiques physico-chimiques et dynamique de tran... more Pas de résumé disponible. PERRET, Didier. Caractéristiques physico-chimiques et dynamique de transport des formes du fer dans un lac eutrophe. Thèse de doctorat : Univ. Genève, 1990, no. Sc. 2395 DOI : 10.13097/archive-ouverte/unige:105363
Journal of Microscopy, 1998
Electron energy‐loss spectroscopy (EELS) and elemental imaging under the energy‐filtered transmis... more Electron energy‐loss spectroscopy (EELS) and elemental imaging under the energy‐filtered transmission electron microscope are powerful tools for the characterization of iron‐rich particles present in natural waters. Features present in EEL spectra (Fe‐M2,3 Fe‐L2,3 and O‐K ionization edges) of goethite (α‐FeOOH) have been studied with an energy filter operated at 80 keV to determine optimal quantification and elemental imaging of Fe‐rich natural aquatic particles in the 30–200 nm range of thickness. For quantitative aims, the Fe‐M2,3 ionization edge cannot be used easily, but the Fe‐L2,3 edge provides more accurate results owing to a better background extrapolation. The partial cross‐section of the Fe(III) M shell has been determined for iron oxide. The use of two‐windows (jump‐ratio) and three‐windows (background stripping) imaging methods is discussed in relation to the specimen thickness.
Journal of Chemical Education, 2015
A small-scale wastewater cleaning plant is described that includes the key physical pretreatment ... more A small-scale wastewater cleaning plant is described that includes the key physical pretreatment steps followed by the chemical treatment of mud by flocculation. Water, clay particles, and riverside deposits mimicked odorless wastewater. After a demonstration of the optimization step, the flocculation process was carried out with iron(III) chloride and a cationic polyelectrolyte and lasted less than 10 s for 7 L of wastewater. This experiment is primarily targeted toward high school students to give a real world demonstration of solution and colloid chemistry, but is also useful for a more general audience. The demonstration has already been successfully presented to 700 visitors.
Water Research, 1994
The particle size distribution in the Rhine River near Basle (Switzerland) was measured for a per... more The particle size distribution in the Rhine River near Basle (Switzerland) was measured for a period of over 1 year. Peaks in the measured size distributions were consistently observed in the ranges of 100200, 300700 nm and 13 μm. The size distributions observed did not ...
Physics and Chemistry of the Earth, 1998
CHIMIA International Journal for Chemistry, 2014
Water science and technology : a journal of the International Association on Water Pollution Research, 2004
State-of-the-art information is presented on the analysis, by transmission electron microscopy (T... more State-of-the-art information is presented on the analysis, by transmission electron microscopy (TEM), of aquatic colloidal particles in the size range of 3 to 500 nm least dimension, with a focus on nanoparticles (1-100 nm). Case studies include selections from both natural waters and waters undergoing treatment. The "species" of nano-particles receiving the greatest attention are: humic substances, polysaccharide fibrils, hydrous iron oxides, viruses, clay minerals, refractory cell debris, and heavy metal agglomerates on biological surfaces. Artifacts and how to both detect and minimize them are outlined. Correlative use of TEM with other imaging techniques is emphasized, along with associated spectroscopy. Noted is the potential of computerized image analysis for quantifying colloids on a "per colloid species" basis, using water samples centrifuged onto electron microscope grids.
Fresenius' journal of analytical chemistry, 2001
For some saline environments (e.g. deeply percolating groundwater, interstitial water in marine s... more For some saline environments (e.g. deeply percolating groundwater, interstitial water in marine sediments, water sample collected after several steps of fractionation) the volume of water sample available is limited. A technique is presented which enables simultaneous determination of major and trace elements after preconcentration of only 60 mL sample on chelating resins. Chelex-100 and Chelamine were used for the preconcentration of trace elements (Cd, Cu, Pb, Zn, Sc) and rare earth elements (La, Ce, Nd, Yb) from saline water before their measurement by inductively coupled plasma mass spectrometry. Retention of the major elements (Na, Ca, Mg) by the Chelamine resin was lower than by Chelex; this enabled their direct measurement in the solution after passage through the resin column. For trace metal recoveries both resins yield the same mass balance. Only Chelex resin enabled the quantitative recovery of rare earth elements. The major elements, trace metals and rare earth elements ...
Cancer research, Jan 15, 2001
157Gd is a potential agent for neutron capture cancer therapy (GdNCT). We directly observed the m... more 157Gd is a potential agent for neutron capture cancer therapy (GdNCT). We directly observed the microdistribution of Gd in cultured human glioblastoma cells exposed to Gd-diethylenetriaminepentaacetic acid (Gd-DTPA). We demonstrated, with three independent techniques, that Gd-DTPA penetrates the plasma membrane, and we observed no deleterious effect on cell survival. A systematic microchemical analysis revealed a higher Gd accumulation in cell nuclei compared with cytoplasm. This is significant for prospective GdNCT because the proximity of Gd to DNA increases the cell-killing potential of the short-range, high-energy electrons emitted during the neutron capture reaction. We also exposed Gd-containing cells to thermal neutrons and demonstrated the GdNC reaction effectiveness in inducing cell death. These results in vitro stimulated in vivo Gd-DTPA uptake studies, currently underway, in human glioblastoma patients.
Physics and Chemistry of the Earth, 1998
The spatial evolution of colloids from a drained peat bog to a river was studied in a karstic wat... more The spatial evolution of colloids from a drained peat bog to a river was studied in a karstic watershed (Jura Mountains, Switzerland) by bulk chemistry and electron microscopy. Raw waters (peat bog pore water, water from artificial drains and river water) were analyzed using ICP (Fe, Ca), Colorimetry (Fe2+), TOC and UV (organic matter) and analytical electron microscopies (TEM-EDS, STEM-EDS,
Environmental Particles, 2019
Apparatus for collecting body fluids at an internal cavity of the body of a living being. An encl... more Apparatus for collecting body fluids at an internal cavity of the body of a living being. An enclosure is introduced into a body cavity with the enclosure in a contracted or evacuated condition. The enclosure has structure permitting body fluid to enter into the enclosure but not to flow out of the latter. A suitable triggering structure is provided to respond to the presence of a body fluid in order to trigger the release of the enclosure for collection, whereupon the enclosure sucks body fluid into the interior of the enclosure, with the enclosure having a structure such as a one-way valve which provides conditions permitting the fluid to flow into the enclosure but not to flow out of the latter. Thereafter, the enclosure is removed from the body cavity so that information can be obtained with respect to the fluid which is collected in the enclosure. The enclosure preferably contains an additive for providing a predetermined desired result with respect to a collected body fluid.
CHIMIA International Journal for Chemistry, 2019
Brock/Springer Series in Contemporary Bioscience, 1990
The complexity involved in studying the biogeochemical cycles of particles and colloids in freshw... more The complexity involved in studying the biogeochemical cycles of particles and colloids in freshwaters is the result of several different factors: the great number of appearance and disappearance fluxes of these species, the difficulties associated with distinguishing and measuring those fluxes, and the difficulty of sampling colloidal particles without denaturation before their characterization. On the other hand, information obtained in laboratory studies of synthetic colloids are not always representative of the mechanisms encountered in heterogeneous natural environments. This article, taking autochthonous iron-rich colloids as a model, summarizes the state of the art concerning current knowledge of these colloids and emphasizes the need to develop new techniques specifically oriented towards analysis of natural colloids and their fluxes while taking care to minimize artifacts introduced by presently employed techniques. Finally, as a pertinent illustration, both the problems and the future uses of well-known filtration techniques are considered.
Note: Lawrence Berkeley Lab, Berkeley, CA 94720 USA.Lorusso, GF, Lawrence Berkeley Lab, 1 Cyclotr... more Note: Lawrence Berkeley Lab, Berkeley, CA 94720 USA.Lorusso, GF, Lawrence Berkeley Lab, 1 Cyclotron Rd,MS 2-400, Berkeley, CA 94720 USA.ISI Document Delivery No.: BK48CArticle7th International Symposium on Neutron Capture TherapySEP 04-07, 1996ZURICH, SWITZERLANDSARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS Reference LSE-CHAPTER-1997-004 Record created on 2006-10-03, modified on 2017-05-12
Journal of Microscopy, 2008
Electron energy‐loss spectroscopy (EELS) and elemental imaging under the energy‐filtered transmis... more Electron energy‐loss spectroscopy (EELS) and elemental imaging under the energy‐filtered transmission electron microscope are powerful tools for the characterization of iron‐rich particles present in natural waters. Features present in EEL spectra (Fe‐M2,3 Fe‐L2,3 and O‐K ionization edges) of goethite (α‐FeOOH) have been studied with an energy filter operated at 80 keV to determine optimal quantification and elemental imaging of Fe‐rich natural aquatic particles in the 30–200 nm range of thickness. For quantitative aims, the Fe‐M2,3 ionization edge cannot be used easily, but the Fe‐L2,3 edge provides more accurate results owing to a better background extrapolation. The partial cross‐section of the Fe(III) M shell has been determined for iron oxide. The use of two‐windows (jump‐ratio) and three‐windows (background stripping) imaging methods is discussed in relation to the specimen thickness.
Aquatic Microbial Ecology, 1998
Pas de résumé disponible. PERRET, Didier. Caractéristiques physico-chimiques et dynamique de tran... more Pas de résumé disponible. PERRET, Didier. Caractéristiques physico-chimiques et dynamique de transport des formes du fer dans un lac eutrophe. Thèse de doctorat : Univ. Genève, 1990, no. Sc. 2395 DOI : 10.13097/archive-ouverte/unige:105363
Journal of Microscopy, 1998
Electron energy‐loss spectroscopy (EELS) and elemental imaging under the energy‐filtered transmis... more Electron energy‐loss spectroscopy (EELS) and elemental imaging under the energy‐filtered transmission electron microscope are powerful tools for the characterization of iron‐rich particles present in natural waters. Features present in EEL spectra (Fe‐M2,3 Fe‐L2,3 and O‐K ionization edges) of goethite (α‐FeOOH) have been studied with an energy filter operated at 80 keV to determine optimal quantification and elemental imaging of Fe‐rich natural aquatic particles in the 30–200 nm range of thickness. For quantitative aims, the Fe‐M2,3 ionization edge cannot be used easily, but the Fe‐L2,3 edge provides more accurate results owing to a better background extrapolation. The partial cross‐section of the Fe(III) M shell has been determined for iron oxide. The use of two‐windows (jump‐ratio) and three‐windows (background stripping) imaging methods is discussed in relation to the specimen thickness.
Journal of Chemical Education, 2015
A small-scale wastewater cleaning plant is described that includes the key physical pretreatment ... more A small-scale wastewater cleaning plant is described that includes the key physical pretreatment steps followed by the chemical treatment of mud by flocculation. Water, clay particles, and riverside deposits mimicked odorless wastewater. After a demonstration of the optimization step, the flocculation process was carried out with iron(III) chloride and a cationic polyelectrolyte and lasted less than 10 s for 7 L of wastewater. This experiment is primarily targeted toward high school students to give a real world demonstration of solution and colloid chemistry, but is also useful for a more general audience. The demonstration has already been successfully presented to 700 visitors.
Water Research, 1994
The particle size distribution in the Rhine River near Basle (Switzerland) was measured for a per... more The particle size distribution in the Rhine River near Basle (Switzerland) was measured for a period of over 1 year. Peaks in the measured size distributions were consistently observed in the ranges of 100200, 300700 nm and 13 μm. The size distributions observed did not ...
Physics and Chemistry of the Earth, 1998
CHIMIA International Journal for Chemistry, 2014
Water science and technology : a journal of the International Association on Water Pollution Research, 2004
State-of-the-art information is presented on the analysis, by transmission electron microscopy (T... more State-of-the-art information is presented on the analysis, by transmission electron microscopy (TEM), of aquatic colloidal particles in the size range of 3 to 500 nm least dimension, with a focus on nanoparticles (1-100 nm). Case studies include selections from both natural waters and waters undergoing treatment. The "species" of nano-particles receiving the greatest attention are: humic substances, polysaccharide fibrils, hydrous iron oxides, viruses, clay minerals, refractory cell debris, and heavy metal agglomerates on biological surfaces. Artifacts and how to both detect and minimize them are outlined. Correlative use of TEM with other imaging techniques is emphasized, along with associated spectroscopy. Noted is the potential of computerized image analysis for quantifying colloids on a "per colloid species" basis, using water samples centrifuged onto electron microscope grids.
Fresenius' journal of analytical chemistry, 2001
For some saline environments (e.g. deeply percolating groundwater, interstitial water in marine s... more For some saline environments (e.g. deeply percolating groundwater, interstitial water in marine sediments, water sample collected after several steps of fractionation) the volume of water sample available is limited. A technique is presented which enables simultaneous determination of major and trace elements after preconcentration of only 60 mL sample on chelating resins. Chelex-100 and Chelamine were used for the preconcentration of trace elements (Cd, Cu, Pb, Zn, Sc) and rare earth elements (La, Ce, Nd, Yb) from saline water before their measurement by inductively coupled plasma mass spectrometry. Retention of the major elements (Na, Ca, Mg) by the Chelamine resin was lower than by Chelex; this enabled their direct measurement in the solution after passage through the resin column. For trace metal recoveries both resins yield the same mass balance. Only Chelex resin enabled the quantitative recovery of rare earth elements. The major elements, trace metals and rare earth elements ...
Cancer research, Jan 15, 2001
157Gd is a potential agent for neutron capture cancer therapy (GdNCT). We directly observed the m... more 157Gd is a potential agent for neutron capture cancer therapy (GdNCT). We directly observed the microdistribution of Gd in cultured human glioblastoma cells exposed to Gd-diethylenetriaminepentaacetic acid (Gd-DTPA). We demonstrated, with three independent techniques, that Gd-DTPA penetrates the plasma membrane, and we observed no deleterious effect on cell survival. A systematic microchemical analysis revealed a higher Gd accumulation in cell nuclei compared with cytoplasm. This is significant for prospective GdNCT because the proximity of Gd to DNA increases the cell-killing potential of the short-range, high-energy electrons emitted during the neutron capture reaction. We also exposed Gd-containing cells to thermal neutrons and demonstrated the GdNC reaction effectiveness in inducing cell death. These results in vitro stimulated in vivo Gd-DTPA uptake studies, currently underway, in human glioblastoma patients.
Physics and Chemistry of the Earth, 1998
The spatial evolution of colloids from a drained peat bog to a river was studied in a karstic wat... more The spatial evolution of colloids from a drained peat bog to a river was studied in a karstic watershed (Jura Mountains, Switzerland) by bulk chemistry and electron microscopy. Raw waters (peat bog pore water, water from artificial drains and river water) were analyzed using ICP (Fe, Ca), Colorimetry (Fe2+), TOC and UV (organic matter) and analytical electron microscopies (TEM-EDS, STEM-EDS,