Publications by authors named "Cecile Marcelot"

The possibility of automatically aligning the transmission electron microscope (TEM) is explored using an approach based on artificial intelligence (AI). After presenting the general concept, we test the method on the first step of the alignment process which involves centering the condenser aperture. We propose using a convolutional neural network (CNN) that learns to predict the x and y-shifts needed to realign the aperture in one step.

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The detective quantum efficiency (DQE) is generally accepted as the main figure of merit for the comparison between electron detectors, and most of the time given as a unique number at the Nyquist frequency while it is known to vary with electron dose. It is usually estimated, thanks to a method improved by McMullan in 2009. The purpose of this work is to analyze and to criticize this DQE extraction method on the basis of measurement and model results, and to give recommendations for fair comparison between detectors, wondering if the DQE is the right figure of merit for electron detectors.

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A versatile strategy to create an inducible protein assembly with predefined geometry is demonstrated. The assembly is triggered by a binding protein that staples two identical protein bricks together in a predictable spatial conformation. The brick and staple proteins are designed for mutual directional affinity and engineered by directed evolution from a synthetic modular repeat protein library.

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Article Synopsis
  • 2D ultrathin metal nanostructures, specifically nanosheets of face-centered cubic (fcc) metals like platinum, have unique properties and advantages for catalysis due to their high surface-to-volume ratios and low-coordinated sites.
  • The selective synthesis of platinum nanosheets is achieved through a seeded-growth method, focusing on preserving defects in the precursor seeds to promote effective 2D growth.
  • Testing the catalytic performance of these platinum nanosheets in phenylacetylene hydrogenation reveals that they outperform traditional commercial Pt/C catalysts in terms of stability and selectivity to styrene.
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II-V semiconductor nanocrystals such as CdP and ZnP have enormous potential as materials in next-generation optoelectronic devices requiring active optical properties across the visible and infrared range. To date, this potential has been unfulfilled due to their inherent instability with respect to air and moisture. Core-shell system CdP/ZnP is synthesized and studied from structural (morphology, crystallinity, shell diameter), chemical (composition of core, shell, and ligand sphere), and optical perspectives (absorbance, emission-steady state and time resolved, quantum yield, and air stability).

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Lanthanide (Ln)-doped upconversion nanoparticles (UCNPs) often suffer from weak luminescence, especially when their sizes are ultrasmall (less than 10 nm). Enhancing the upconversion luminescence (UCL) efficiency of ultrasmall UCNPs has remained a challenge that must be undertaken if any practical applications are to be envisaged. Herein, we present a Ln-doped oxysulfide@fluoride core/shell heterostructure which shows efficient UCL properties under 980 nm excitation and good stability in solution.

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Article Synopsis
  • Researchers developed single crystalline FeCo nanostars using a straightforward organometallic method, which allowed for direct synthesis without needing a complicated seed-mediated growth process.* -
  • The nanostars are made up of 8 tetrahedrons and showcase high magnetization levels similar to bulk materials, measured at 235 A·m·kg.* -
  • Advanced imaging techniques revealed complex 3D spin configurations influenced by both dipolar and exchange interactions, highlighting how the unique shape of these nanostars can significantly alter their magnetic properties.*
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Hypothesis: The capability of making 3D directed assembly of colloidal nanoparticles on surfaces, instead of 2D one, is of major interest to generate, tailor, and enhance their original functionalities. The nanoxerography technique, i.e.

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Article Synopsis
  • Researchers conducted a detailed analysis of the magnetic properties of Co-rich CoNi nanowires using electron holography, focusing on their structural features at the nanoscale.
  • The nanowires exhibited both face-centered cubic (fcc) and hexagonal close packed (hcp) crystal structures, and the magnetic configurations showed significant complexity, with distinct vortex formations and axial orientations linked to these structures.
  • Local variations in chemical composition influenced the crystalline orientations and magnetic behaviors, and micromagnetic simulations helped clarify the relationship between these structural differences and the observed magnetic states.
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Natural biocomposites are shaped by proteins that have evolved to interact with inorganic materials. Protein directed evolution methods which mimic Darwinian evolution have proven highly successful to generate improved enzymes or therapeutic antibodies but have rarely been used to evolve protein-material interactions. Indeed, most reported studies have focused on short peptides and a wide range of oligopeptides with chemical binding affinity for inorganic materials have been uncovered by phage display methods.

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Description of the relationship between protein structure and function remains a primary focus in molecular biology, biochemistry, protein engineering and bioelectronics. Moreover, the investigation of the protein conformational changes after adhesion and dehydration is of importance to tackle problems related to the interaction of proteins with solid surfaces. In this paper the conformational changes of wild-type Discosoma recombinant red fluorescent proteins (DsRed) adhered on silver nanoparticles (AgNPs)-based nanocomposites are explored via surface-enhanced Raman scattering (SERS).

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Article Synopsis
  • Researchers need nanocrystals with specific shapes for better catalysts, but traditional methods don’t allow for shape control.
  • This study successfully synthesized concave platinum nanocubes with {110} facets and showed how they grow on a Pt(111) support, creating detailed nanostructured surfaces.
  • By carefully selecting the support's crystallographic orientation, scientists can selectively immobilize desired nanostructures from a mixed solution, leading to new possibilities in nanocrystal development.
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Magnetoelectric coupling at multiferroic interfaces is a promising route toward the nonvolatile electric-field control of magnetization. Here, we use optical measurements to study the static and dynamic variations of the interface magnetization induced by an electric field in Co/PbZr0.2Ti0.

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