Search results for "microscopie"

Étude par microscopie électronique et spectroscopie de films minces catalytiques pour micro piles à combustibles

2016

Předložená dizertační práce se zabývá studiem nových katalyzátorů na bázi kov-oxid vhodných pro použití v palivových článcích na straně anody. Platinou dopovaný oxid ceru připravený magnetronovým naprašováním ve formě tenkých vrstev na uhlíkových mezivrstvách nesených křemíkovým substrátem byl zkoumán prostřednictvím mikroskopických a spektroskopických metod. Vliv složení uhlíkového nosiče (a-C a CNx filmy), depozičního času CeOx vrstvy a dalších depozičních parametrů, např. depoziční rychlosti, složení pracovní atmosféry a Pt koncentrace na morfologii Pt-CeOx vrstev byl studován převážně pomocí transmisní elektronové mikroskopie (TEM). Získané výsledky ukazují, že vhodnou kombinací depozič…

Nano-structured molecular thin films for bio-sensing and plastic-electronics with improved efficiency/cost ratio

2008

Role of tir and intimin in the virulence of rabbit enteropathogenic Escherichia coli serotype O103:H2.

2000

ABSTRACT Attaching and effacing (A/E) rabbit enteropathogenic Escherichia coli (REPEC) strains belonging to serogroup O103 are an important cause of diarrhea in weaned rabbits. Like human EPEC strains, they possess the locus of enterocyte effacement clustering the genes involved in the formation of the A/E lesions. In addition, pathogenic REPEC O103 strains produce an Esp-dependent but Eae (intimin)-independent alteration of the host cell cytoskeleton characterized by the formation of focal adhesion complexes and the reorganization of the actin cytoskeleton into bundles of stress fibers. To investigate the role of intimin and its translocated coreceptor (Tir) in the pathogenicity of REPEC, …

Study of the dynamics of biomolecules by high speed atomic force microscopy and surface enhanced Raman spectroscopy

2015

This thesis focuses on the coupling of High–Speed Atomic Force Microscopy (HS-AFM) and Surface Enhanced Raman Spectroscopy (SERS) for biomolecule analysis. We have designed a fabrication protocol to manufacture “SERS-active” substrates. The efficacy of gold, silver and gold-silver bimetallic crystalline nanoparticle substrates were evaluated. We have investigated the impact of optical and morphological features of the substrates on Raman signal intensity by analyzing well-known samples such as bipyridine ethylene and methylene blue molecules. We took an interest in three distinct biological problematics with HS-AFM and SERS analyses. First, we have detected the chemical signature of cytochr…

Growth of metal/oxide periodic multilayer : relation between structure and electrical behaviour in systems based on titanium and tungsten

2014

Periodic multilayers have found many applications in the fields of optics, mechanics or electronics. However, few studies focus on the electrical responses of the metal/oxide periodic structures versus temperature. The interest of this work was focused on the characterization of the multilayers and their electrical properties versus temperature. In TiO/Ti/TiO/TiO2 and WO/W/WO/WO3 systems produced by the reactive gas pulsing process, sample structures were established by transmission electron microscopy for sublayers thicknesses between 1.3 and 50.8 nm. Then, this study highlights a modification of conventional electrical behavior versus temperature. An empirical relationship was established…

Applications and development of acoustic and microwave atomic force microscopy for high resolution tomography analysis

2016

The atomic force microscope (AFM) is a powerful tool for the characterization of organic and inorganic materials of interest in physics, biology and metallurgy. However, conventional scanning probe microscopy techniques are limited to the probing surface properties, while the subsurface analysis remains difficult beyond nanoindentation methods. Thus, the present thesis is focused on two novel complementary scanning probe techniques for high-resolution volumetric investigation that were develop to tackle this persisting challenge in nanometrology.The first technique considered, called Mode Synthesizing Atomic Force Microscopy (MSAFM), has been exploited in collaboration with Dr. Laurene Teta…

Classification par méthodes d’apprentissage supervisé et faiblement superviséd’images multimodales pour l’aide au diagnostic du lentigo malin en derm…

2021

Carried out in collaboration with the Saint-Étienne University Hospital, this work provides additional information to help the skin diagnosis by providing new decision methods on Lentigo Maligna and Lentigo Maligna Melanoma pathologies. To this end, the modalities regularly used in clinical conditions are made available to this work and are orchestrated within a multimodal process. Among image modalities, may be mentioned the clinical photography, the dermatoscopy, and the confocal reflectance microscopy. Initially, the first steps of this manuscript focus on reflectance confocal microscopy as the work in computer diagnostic assistance is relatively underdeveloped, in particular on the dete…

Analyse locale des sensibilités des lectures angulaires, spectroscopiques et ellipsométriques de la Résonance des Plasmons de Surface en vue de la mi…

2006

The fluorescence labelling, used by the fluorescence biochips, is known to change the charge distribution of the labelled molecules and then modify their biological activity. Among label free biosensors, we choose an optical detection, such as spectroscopic ellipsometry and/or surface plasmon resonance (SPR) of the biolayers.These optical techniques are based on the measurement of both thickness and optical index of the adsorbed biolayer. An AFM statistical measurement of the thickness of functionalized lithographed microstructures has been performed in order to determine the thickness of the biolayers.We have shown that the spectroscopic reading of the SPR phase shift is 100 times more sen…

Identification of the contaminants present on the surface of lactose for pharmaceutical use and analysis of the impact of their presence on the inter…

2018

The discovery of the problem will go through training techniques at the nanoscale characterization and chemical analysis, the discovery of the industrial problem in society Armor Proteins, the validation of a pharmaceutical lactose. With the aim to increase our knowledge on powders for food or pharmaceutical use, we propose to study the effect of manufacturing processes, shaping, granulation on the reactivity of powders. The first part is devoted to the effect of purity on interactions-Lactose Lactose and Lactose-API measured / quantified by near-field techniques (AFM, SMM, MSAFM) under ambient atmosphere and under stressful conditions storage. Deriving a second portion of the preceding par…

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…