Publications by authors named "Dubois P"

Purpose: In order to better understand if the metabolic responses of echinoids could be related to their acid-base status in an ocean acidification context, we studied the response of an intertidal sea urchin species, Paracentrotus lividus, submitted to low pH at two different temperatures.

Methods: Individuals were submitted to control (8.0) and low pH (7.

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Skin carcinomas are among the most commonly diagnosed tumors in the world. In this study, we investigated the transfection of immortalized keratinocytes, used as an in vitro model for skin carcinoma, using the antisense technology and poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA)-based copolymers. In order to improve the transfection efficiency of the classic PDMAEMA polymers, copolymers were synthesized including a poly(N-morpholino)ethylmethacrylate) (PMEMA) moiety for an improved proton-sponge effect, intended to favour the release of the oligonucleotide from the acidic endosome.

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We report the efficient one-step synthesis and detailed physicochemical evaluation of novel biocompatible nanosystems useful for cancer therapeutics and diagnostics (theranostics). These systems are the superparamagnetic iron oxide nanoparticles (SPIONs) carrying the anticancer drug doxorubicin and coated with the covalently bonded biocompatible polymer poly(ethylene glycol) (PEG), native and modified with the biological cancer targeting ligand folic acid (PEG-FA). These multifunctional nanoparticles (SPION-DOX-PEG-FA) are designed to rationally combine multilevel mechanisms of cancer cell targeting (magnetic and biological), bimodal cancer cell imaging (by means of MRI and fluorescence), and bimodal cancer treatment (by targeted drug delivery and by hyperthermia effect).

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Background: Neuromuscular blocking agents have always shown wide inter-individual variability when it comes to their duration of action. This prevents clinicians from anticipating the evolution of the neuromuscular block for any given patient. With this study, we aimed to assess the nature of the relationships existing between different time course parameters used to describe paralysis onset and offset.

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New polyesters incorporating a variable quantity of imidazolium rings along the backbone are synthesized by Huisgen 1,3-dipolar cycloaddition ("click" reaction). Subsequently, the imidazolium-grafted copolymers reveal an efficient dispersing ability toward the carbon nanotubes (CNTs) through supramolecular interactions in organic media. Interestingly, these compounds offer a simple and reliable strategy to control the quantity of dispersed CNTs as a function of imidazolium content.

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Using variants from the 1000 Genomes Project pilot European CEU dataset and data from additional resequencing studies, we densely genotyped 183 non-HLA risk loci previously associated with immune-mediated diseases in 12,041 individuals with celiac disease (cases) and 12,228 controls. We identified 13 new celiac disease risk loci reaching genome-wide significance, bringing the number of known loci (including the HLA locus) to 40. We found multiple independent association signals at over one-third of these loci, a finding that is attributable to a combination of common, low-frequency and rare genetic variants.

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The common sea star Asterias rubens represents a key-species of the North-Eastern Atlantic macro benthic community. The cells of their immune system, known as coelomocytes, are the first line of defence against environmental hazards. Here, we report the results of investigations on the immune cells response of sea stars exposed to marine environmental pollution for long periods.

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Echinoderms are known to readily incorporate metals in their calcified endoskeleton. It is currently unclear if this has an impact on the skeleton function or if this can be considered as a detoxification mechanism. In the present work, populations of the sea urchin Echinus acutus and the starfish Asterias rubens were studied in stations distributed along a metal contamination gradient in a Norwegian fjord (Sørfjord).

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This work relies on the CNT dispersion in either solution or a polymer matrix through the formation of a three-component supramolecular system composed of PEO-b-PLLA diblock copolymer, carbon nanotubes (CNTs), and lithium chloride. According to a one-pot procedure in solution, the "self-assembly" concept has demonstrated its efficiency using suspension tests of CNTs. Characterizations of the supramolecular system by photon correlation spectroscopy, Raman spectroscopy, and molecular dynamics simulations highlight the charge transfer interaction from the CNTs toward the PEO-b-PLLA/LiCl complex.

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The massive basal skeleton of a few remnant living hypercalcified sponges rediscovered since the 1960s are valuable representatives of ancient calcium carbonate biomineralization mechanisms in basal Metazoa. A multi-scale mineralogical characterization of the easily accessible Mediterranean living hypercalcified sponge belonging to Calcarea, Petrobiona massiliana (Vacelet and Lévi, 1958), was conducted. Oriented observations in light and electron microscopy of mature and growing areas of the Mg-calcite basal skeleton were combined in order to describe all structural levels from the submicronic to the macroscopic scale.

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This paper reports the results of the first dynamic labeling experiment with regenerating spines of sea urchins Paracentrotus lividus using the stable isotope ²⁶Mg and NanoSIMS high-resolution isotopic imaging, which provide a direct information about the growth process. Growing spines were labeled twice (for 72 and 24 h, respectively) by increasing the abundance of ²⁶Mg in seawater. The incorporation of ²⁶Mg into the growing spines was subsequently imaged with the NanoSIMS ion microprobe.

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Cross-linked poly(ε-caprolactone) (PCL)-based polyesterurethane (PUR) systems have been synthesized through Diels-Alder reactions by reactive extrusion. The Diels-Alder and retro-Diels-Alder reactions proved to be useful for enhancing the molecular motion of PCL-based systems, and therefore their crystallization ability, in the design of cross-linked semicrystalline polymers with one-way and two-way shape-memory properties. Successive reactions between α,ω-diol PCL (PCL(2) ), furfuryl alcohol, and methylene diphenyl 4,4'-diisocyanate straightforwardly afforded the α,ω-furfuryl PCL-based PUR systems, and subsequent Diels-Alder reactions with N,N-phenylenedimaleimide afforded the thermoreversible cycloadducts.

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Ion mobility spectrometry coupled with mass spectrometry was used to experimentally determine the three-dimensional structure of multiply charged sodium cationized polylactides (PLA). In particular, the experiments were conducted to evaluate the influence of the charge state and the size on the gas-phase conformation of cationized PLA. The measured collision cross sections were then compared to calculated values obtained by computational chemistry methods.

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One of the new strategies to improve cancer chemotherapy is based on new drug delivery systems, like the polyethylene glycol-coated superparamagnetic iron oxide nanoparticles (PEG-SPION, thereafter called PS). In this study, PS are loaded with doxorubicin (DOX) anticancer drug, using a pre-formed DOX-Fe(2+) complex reversible at lower pH of tumour tissues and cancer cells. The DOX loaded PS (DLPS, 3% w/w DOX/iron oxide) present a hydrodynamic size around 60nm and a zeta potential near zero at physiological pH, both parameters being favourable for increased colloidal stability in biological media and decreased elimination by the immune system.

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Adjuvants are increasingly used by the vaccine research and development community, particularly for their ability to enhance immune responses and for their dose-sparing properties. However, they are not readily available to the majority of public sector vaccine research groups, and even those with access to suitable adjuvants may still fail in the development of their vaccines because of lack of knowledge on how to correctly formulate the adjuvants. This shortcoming led the World Health Organization to advocate for the establishment of the Vaccine Formulation Laboratory at the University of Lausanne, Switzerland.

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A new concept to build shape memory polymers (SMP) combining outstanding fixity and recovery ratios (both above 99% after only one training cycle) typical of chemically crosslinked SMPs with reprocessability restricted to physically crosslinked SMPs is demonstrated by covalently bonding, through thermoreversible Diels-Alder (DA) adducts, star-shaped poly(ε-caprolactones) (PCL) end-functionalized by furan and maleimide moieties. A PCL network is easily prepared by melt-blending complementary end-functional star polymers in retro DA regime, then by curing at lower temperature to favour the DA cycloaddition. Such covalent network can be reprocessed when heated again at the retro DA temperature.

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In the present work, cellulose nanowhiskers (CNWs), extracted from ramie fibers, were incorporated in polylactide (PLA)-based composites. Prior to the blending, PLA chains were chemically grafted on the surface of CNW to enhance the compatibilization between CNW and the hydrophobic polyester matrix. Ring-opening polymerization of l-lactide was initiated from the hydroxyl groups available at the CNW surface to yield CNW-g-PLA nanohybrids.

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New functionalized poly(3-hexylthiophene)s (P3HT) have been designed and synthesized with the aim of increasing the dispersion of carbon nanotubes (CNT) in solutions and in thin films of semiconducting polymers. Dispersion in solution has been assessed by sedimentation tests while the thin film morphology has been analyzed by TEM and AFM. Both the physisorption of P3HT chains (via pyrene end-groups) or their chemical grafting (onto amine functions generated on the CNT surface) lead to a much better dispersion in solution and in the solid.

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Background: The Plasmodium falciparum pre-erythrocytic stage candidate vaccine RTS,S is being developed for protection of young children against malaria in sub-Saharan Africa. RTS,S formulated with the liposome based adjuvant AS01(E) or the oil-in-water based adjuvant AS02(D) induces P. falciparum circumsporozoite (CSP) antigen-specific antibody and T cell responses which have been associated with protection in the experimental malaria challenge model in adults.

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Unlabelled: The recombinant circumsporozoite protein (CS) based vaccine, RTS,S, confers protection against Plasmodium falciparum infection in controlled challenge trials and in field studies. The RTS,S recombinant antigen has been formulated with two adjuvant systems, AS01 and AS02, which have both been shown to induce strong specific antibody responses and CD4 T cell responses in adults. As infants and young children are particularly susceptible to malaria infection and constitute the main target population for a malaria vaccine, we have evaluated the induction of adaptive immune responses in young children living in malaria endemic regions following vaccination with RTS,S/AS01(E) and RTS,S/AS02(D).

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Metallic oxides have been successfully investigated for the recycling of polylactide (PLA) via catalyzed unzipping depolymerization allowing for the selective recovery of lactide monomer. In this contribution, a metallic oxide nanofiller, that is, ZnO, has been dispersed into PLA without detrimental polyester degradation yielding PLA/ZnO nanocomposites directly suitable for producing films and fibers. The nanocomposites were produced by melt-blending two different grades of PLA with untreated ZnO and surface-treated ZnO nanoparticles.

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Background: Current ST-segment elevation myocardial infarction guidelines regarding reperfusion strategy are based on trials conducted before the application of routine invasive evaluation after thrombolysis. Modern thrombolysis may affect the previously observed mortality difference between primary percutaneous coronary intervention (PPCI) and thrombolysis.

Methods: In-hospital mortality was prospectively assessed in 5295 patients with ST-segment elevation myocardial infarction admitted to 73 Belgian hospitals from July 1, 2007, through December 31, 2009.

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