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C Fretigny

Publications and source records attributed to C Fretigny.

5 recordsLinked to original sources
PubMed2006

Viscoelastic dewetting of a polymer film on a liquid substrate.

The Dewetting of thin polymer films (60-300 nm) on a non-wettable liquid substrate has been studied in the vicinity of their glass transition temperature. In our experiment, we observe a global contraction of the film while its thickness remains uniform. We show that, in this case, the strain corresponds to simple extension, and we verify that it is linear with the stress applied by the surface tension. This allows direct measurement of the stress/strain response as a function of time, and thus permits the measurement of an effective compliance of the thin films. It is, however, difficult to obtain a complete viscoelastic characterization, as the short time response is highly dependant on the physical age of the sample. Experimental results underline the effects of residual stress and friction when dewetting is analyzed on rigid substrates.

Computer Simulation↗
PubMed2002

Red blood cells imaging and antigen-antibody interaction measurement.

In the present study the atomic force microscope (AFM) was used to image the surface morphology of red blood cells (RBC) for the first time. The AFM yielded very reproducible images without appreciable modifications of the sample surfaces. In addition to this topographical imaging, we have developed an experimental approach to measure the binding strength between antibody (anti-A), and the RBC antigen A, when reversible bonds between specific molecules such as antigen and antibody mediate the adhesion. The experimental results suggest that the procedure established here may be used for specific antibody detection. This study has also enhanced our understanding under physiological conditions of molecular interaction in particular antigen-antibody.

ABO Blood-Group System↗
PubMed2002

Investigating specific antigen/antibody binding with the atomic force microscope.

The aim of this work is to detect immune complexes without any kind of labelling of each of the immunological species, with a view to create a very sensitive biosensor. This is achieved by using the atomic force microscopy. We have proceeded by imaging the antibody (anti-rabbit IgG) or anti-rabbit IgG moieties adsorbed onto mica surface, before and after incubation of two kinds of antigens: a specific (rabbit IgG) and a non-specific one (sheep IgG). The analysis using the height histograms reveals many interesting features. We propose a general framework for interpreting these analysis, which enables the discrimination between specific and non-specific complexes.

Adsorption↗
PubMed1998

Analysis of the REDOR signal and inversion

An inversion of the REDOR signal to recover the dipolar couplings has been recently proposed [K. T. Mueller et al., Chem. Phys. Lett. 242, 535 (1995)]: The corresponding integral transform was performed by tabulation of the kernel followed by numerical integration. After explicit determination of the inverse REDOR kernel by the Mellin transform method, we propose an alternative inversion method based on Fourier transforms. Representation of the inverse REDOR kernel by its asymptotic expansion reveals that the inverse REDOR operator is essentially a weighted sum of a cosine transform and of its derivative. Consequently, known properties of Fourier transforms can easily be transposed to the REDOR inversion, allowing for a precise discussion of the value of the method. Moreover, the first term of the asymptotic expansion leading to a derivative of a cosine transform, the REDOR inversion is found to be extremely sensitive to noise, thus considerably reducing the useful part of the theoretical dipolar window. Copyright 1998 Academic Press.

Journal Article↗