Search results for " microscopy"
showing 10 items of 1617 documents
Background-free nonlinear Raman microscopy and spectroscopy at interfaces
2010
Gaussian focused beams exhibit specific properties that drive the emitted fields in nonlinear optical microscopy. We discuss here how the basic field and object symmetry properties can be favorably used to obtain background-free images and spectra in third-order nonlinear optical processes. We concentrate here on coherent anti-Stokes Raman scattering (CARS), the non-linear analogue of Raman scattering. In CARS microscopy, the vibrational related (“resonant”) signal is often overwhelmed by an electronic related (“nonresonant”) background. Various strategies have been implemented to circumvent the undesirable effects of this nonresonant background: picosecond pulse excitation, time resolved, …
Generic nature of long-range repulsion mechanism on a bulk insulator?
2017
Dynamic atomic force microscopy measurements are reported that provide evidence for the presence of long-range repulsion in molecular self-assembly on a bulk insulator surface. We present the structures formed from four different benzoic acid derivatives on the (10.4) cleavage plane of calcite kept in ultra-high vacuum. These molecules have in common that they self-assemble into molecular stripes when deposited onto the surface held at room temperature. For all molecules tested, a detailed analysis of the stripe-to-stripe distance distribution reveals a clear deviation from what would be expected for randomly placed, non-interacting stripes (i.e., geometric distribution). When excluding kin…
Growth of zinc-blende GaN on muscovite mica by molecular beam epitaxy
2021
Abstract The mechanisms of plasma-assisted molecular beam epitaxial growth of GaN on muscovite mica were investigated. Using a battery of techniques, including scanning and transmission electron microscopy, atomic force microscopy, cathodoluminescence, Raman spectroscopy and x-ray diffraction, it was possible to establish that, in spite of the lattice symmetry mismatch, GaN grows in epitaxial relationship with mica, with the [11–20] GaN direction parallel to [010] direction of mica. GaN layers could be easily detached from the substrate via the delamination of the upper layers of the mica itself, discarding the hypothesis of a van der Waals growth mode. Mixture of wurtzite (hexagonal) and z…
A mucosal pellicle modifies the physical properties of epithelial
2017
International audience
International Scanning Probe Microscopy Conference
2016
International audience
Technological innovation around protein and cell biochip for diagnosis: a translational research from nanoworld to patient
2009
International audience; A great challenge in biosensors and diagnosis devices relies on the way to reconstitute relevant biological mechanisms on surface of the biochips and which analytical tools are convenient to provide accurate and rapid information on the structures and function of molecules attached to this surface. A better control in the realization of biochips can be obtained in combining different complementary approaches while always keeping in mind the biological key point. Researches in CLIPP are focused towards this objective. Conception, realization and characterization of protein and cell chips are presented. We detail different strategies of materials engineering1,2,3, chem…
Cell imaging connected with protein mapping to investigate glyphosate induced toxicity on human keratinocytes
2009
During the skin ageing which is accelerated by environmental factors, the generated reactive oxygen species make unstable the "proliferation/differentiation/apoptosis" coupling of epidermal cells. A biochemical study, previously realized on human keratinocyte cultures treated by a pesticide, glyphosate, allowed the validation of an in vitro model of skin ageing. In this work, we propose to study the loss of HaCaT cell integrity appearing after this chemical induced-oxidative stress. An original approach, combining a micro- to nanoscale cell characterization and analysis of fluctuating protein expression, is proposed: a) the exploration of cell growth and morphology through fluorescence and …
Increased electron donor and electron acceptor characters enhance the adhesion between oil droplets and cells of Yarrowia lipolytica as evaluated by …
2003
International audience; The adhesion of methyl ricinoleate droplets to cells of the yeast Yarrowia lipolytica was investigated. A new cytometric method, relying on the double staining of fatty globules with Nile Red and of cells with Calcofluor, enabled us to quantify methyl ricinoleate droplet adhesion to cells precultured on a hydrophilic or on a hydrophobic carbon source. In this last case, droplet adsorption was enhanced and a MATS (microbial adhesion to solvents) test revealed that this increase was due to Lewis acid-base interactions and not to an increase in the hydrophobic properties of the cell surface. These preliminary results demonstrate that the developed cytometric method is p…
Exploring the diversity of listeria monocytogenes biofilm architecture by high-throughput confocal laser scanning microscopy and the predominance of …
2015
ABSTRACT Listeria monocytogenes is involved in food-borne illness with a high mortality rate. The persistence of the pathogen along the food chain can be associated with its ability to form biofilms on inert surfaces. While most of the phenotypes associated with biofilms are related to their spatial organization, most published data comparing biofilm formation by L. monocytogenes isolates are based on the quantitative crystal violet assay, which does not give access to structural information. Using a high-throughput confocal-imaging approach, the aim of this work was to decipher the structural diversity of biofilms formed by 96 L. monocytogenes strains isolated from various environments. Pr…
Analysis of fluorescent MRI contrast agent behavior in the liver and thoracic aorta of mice.
2004
To characterize the behavior of magnetofluorescent products injected in mice intravenously.The magnetic resonance imaging (MRI) products were labelled with fluorescent molecules to examine the biodistribution process in vivo and observe them at the cellular level by means of confocal microscopy. Three-dimensional (3D) sequences of images were obtained by spectral analysis of sample preparations in a multiphoton confocal microscope and analyzed by the factor analysis of medical image sequence algorithm, which provides factor curves. Factor images are the result of image-processing methods that utilize information from emission spectra. Preparations are also screened in the counting mode to p…