Publications by authors named "Dominique Begin"

Phosphates in high concentrations are harmful pollutants for the environment, and new and cheap solutions are currently needed for phosphate removal from polluted liquid media. Iron oxide nanoparticles show a promising capacity for removing phosphates from polluted media and can be easily separated from polluted media under an external magnetic field. However, they have to display a high surface area allowing high removal pollutant capacity while preserving their magnetic properties.

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Article Synopsis
  • High-quality graphene is being studied for its potential to improve heat transfer in nanofluids used in fluid circulation systems.
  • A unique mechanical method is used to synthesize few layer graphene (FLG), which is then characterized through advanced microscopy techniques.
  • The research demonstrates that the size of FLG nanosheets and their interface thermal resistance are critical factors influencing the enhancement of thermal conductivity in FLG-based nanofluids.
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One key challenge in the fields of nanomedicine and tissue engineering is the design of theranostic nanoplatforms able to monitor their therapeutic effect by imaging. Among current developed nano-objects, carbon nanotubes (CNTs) were found suitable to combine imaging, photothermal therapy, and to be loaded with hydrophobic drugs. However, a main problem is their resulting low hydrophilicity.

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The in vivo fate and biodegradability of carbon nanotubes is still a matter of debate despite tremendous applications. In this paper we describe a molecular pathway by which macrophages degrade functionalized multi-walled carbon nanotubes (CNTs) designed for biomedical applications and containing, or not, iron oxide nanoparticles in their inner cavity. Electron microscopy and Raman spectroscopy show that intracellularly-induced structural damages appear more rapidly for iron-free CNTs in comparison to iron-loaded ones, suggesting a role of iron in the degradation mechanism.

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Despite numerous applications, the cellular-clearance mechanism of multiwalled carbon nanotubes (MWCNTs) has not been clearly established yet. Previous in vitro studies showed the ability of oxidative enzymes to induce nanotube degradation. Interestingly, these enzymes have the common capacity to produce reactive oxygen species (ROS).

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Article Synopsis
  • The text discusses a method for coating macroscopic supports like β-SiC and α-Al2O3 with a nitrogen-rich carbon layer derived from food-processing materials.
  • This coating creates composites that function as effective metal-free catalysts.
  • These catalysts are designed to enhance key industrial processes pivotal for renewable energy and environmental sustainability.
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The design of graphene-based materials for biomedical purposes is of great interest. Graphene oxide (GO) sheets represent the most widespread type of graphene materials in biological investigations. In this work, thin GO sheets were synthesized and further chemically functionalized with DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid), a stable radiometal chelating agent, by an epoxide opening reaction.

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Nanocomposites combining multiple functionalities in one single nano-object hold great promise for biomedical applications. In this work, carbon nanotubes (CNTs) were filled with ferrite nanoparticles (NPs) to develop the magnetic manipulation of the nanotubes and their theranostic applications. The challenges were both the filling of CNTs with a high amount of magnetic NPs and their functionalization to form biocompatible water suspensions.

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A practically simple top-down process for the exfoliation of graphene (GN) and few-layer graphene (FLG) from graphite is described. We have discovered that a biocompatible amphiphilic pyrene-based hexahistidine peptide is able to exfoliate, functionalize, and dissolve few layer graphene flakes in pure water under exceptionally mild, sustainable and virtually innocuous low intensity cavitation conditions. Large area functionalized graphene flakes with the hexahistidine oligopeptide (His₆-TagGN = His₆@GN) have been produced efficiently at room temperature and characterized by TEM, Raman, and UV spectroscopy.

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Catalytic reactions are generally carried out on supported metals or oxides, which act as an active phase and require impregnation and thermal treatment steps. During tests, the metal or oxide nanoparticles could be further sintered, which would induces deactivation. Direct incorporation of the active phase into the matrix of a support could be an elegant alternative to prevent catalyst deactivation.

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Novel transparent 1D-TiO(2)/few-layer graphene electrodes are realised by the anodic growth of vertically aligned TiO(2) nano-tubes on a few-layer graphene film coated on a glass substrate.

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The functionalisation of carbon nanomaterials with the standard nitric acid treatment is greatly influenced by their graphitic character. The structural order directs the density as well as the nature of the created functional groups and, as a consequence, influences the efficiency of their filling with metal nanoparticles.

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A 3D-structured photocatalytic media was designed for allowing a tubular reactor to work in a traversing-flow mode at low pressure drops with a strong increase in the surface area-to-volume ratio inside the reactor. A protective polysiloxane coating was performed for protecting a structured polyurethane foam and anchoring the active TiO(2) particles. Filled with the 3D-structured solid foam supporting TiO(2) photocatalyst, the reactor could thus take advantages from the static mixer effect and from the low pressure drop resulting from the reticulated foam support.

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