Synthesis and Characterization of Advanced Carbon-Based Nanowires – Study of Composites Actuation Capabilities Containing These Nanowires as Fillers

International audienc

Performance evaluation of the IRIS XL-220 PET/CT system, a new camera dedicated to non-human primates

Background: Non-human primates (NHP) are critical in biomedical research to better understand the pathophysiology of diseases and develop new therapies. Based on its translational and longitudinal abilities along with its non-invasiveness, PET/CT systems dedicated to non-human primates can play an important role for future discoveries in medical research. The aim of this study was to evaluate the performance of a new PET/CT system dedicated to NHP imaging, the IRIS XL-220 developed by Inviscan SAS. This was performed based on the National Electrical Manufacturers Association (NEMA) NU 4-2008 standard recommendations (NEMA) to characterize the spatial resolution, the scatter fraction, the sensitivity, the count rate, and the image quality of the system. Besides, the system was evaluated in real conditions with two NHP with 18F-FDG and (-)-[18F]FEOBV which targets the vesicular acetylcholine transporter, and one rat using 18F-FDG. Results: The full width at half maximum obtained with the 3D OSEM algorithm ranged between 0.89 and 2.11 mm in the field of view. Maximum sensitivity in the 400–620 keV and 250–750 keV energy windows were 2.37% (22 cps/kBq) and 2.81% (25 cps/kBq), respectively. The maximum noise equivalent count rate (NEC) for a rat phantom was 82 kcps at 75 MBq and 88 kcps at 75 MBq for energy window of 250–750 and 400–620 keV, respectively. For the monkey phantom, the maximum NEC was 18 kcps at 126 MBq and 19 kcps at 126 MBq for energy window of 250–750 and 400–620 keV, respectively. The IRIS XL provided an excellent quality of images in non-human primates and rats using 18F-FDG. The images acquired using (-)-[18F]FEOBV were consistent with those previously reported in non-human primates. Conclusions: Taken together, these results showed that the IRIS XL-220 is a high-resolution system well suited for PET/CT imaging in non-human primates

Prenatal exposure to methylphenidate affects the dopamine system and the reactivity to natural reward in adulthood in rats

Background: Methylphenidate (MPH) is a commonly-used medication for the treatment of children with Attention-Deficit/Hyperactivity Disorders (ADHD). However, its prescription to adults with ADHD and narcolepsy raises the question of how the brain is impacted by MPH exposure during pregnancy. The goal of this study was to elucidate the long-term neurobiological consequences of prenatal exposure to MPH using a rat model.Methods: We focused on the effects of such treatment on the adult dopamine (DA) system and on the reactivity of animals to natural rewards.Results: This study shows that adult male rats prenatally exposed to MPH display elevated expression of presynaptic DA markers in the DA cell bodies and the striatum. Our results also suggest that MPH-treated animals could exhibit increased tonic DA activity in the mesolimbic pathway, altered signal-to-noise ratio after a pharmacological stimulation, and decreased reactivity to the locomotor effects of cocaine. Finally, we demonstrated that MPH rats display a decreased preference and motivation for sucrose.Conclusions: This is the first preclinical study reporting long-lasting neurobiological alterations of DA networks as well as alterations in motivational behaviors for natural rewards after a prenatal exposure to MPH. These results raise concerns about the possible neurobiological consequences of MPH treatment during pregnancy.<br/

Electromechanical study of polyurethane films with carbon black nanoparticles for MEMS actuators

International audiencePure polyurethane and nanocomposite carbon black (CB) polyurethane solutions were deposited by spin-coating on a silicon substrate using gold as the adhesion layer and electrode. Different test structures were achieved for electrical and mechanical characterizations. The incorporation of CB nanoparticles in the polyurethane matrix has a significant influence on the dielectric permittivity of the material with an increase of about one third of its value. The Young's modulus of PU and nanocomposite PU films was determined by different characterization methods. Nanoindentation experiments have pointed out a Young's modulus gradient through the film thickness. By performing mechanical tests (tensile, bulge, point deflection) on freestanding films, an average Young's modulus value of about 30 MPa was found as well as a residual stress value of about 0.4 MPa. However, no influence of the presence of the nanoparticles was found. Finally, several MEMS actuators were realized and characterized. At their fundamental resonance frequency, the actuation of the nanocomposite membranes is more efficient than that of pure polyurethane. However, the time constant of the material seems to provide a major barrier for the development of high-frequency PU-based micro-actuators

Immunocytochemistry.

<p>a) GFAP b) DRD1 c) DAT and d) DRD2 expression following AMPH or saline pre-treatment in the NAcc and CPu (mean ±SEM) * p<0.05.</p

Effect of pre-treatment with AMPH on brain monoamines and metabolites.

<p>Effect of pre-treatment with AMPH on brain monoamines and metabolites.</p

ROI analyses of phMRI data.

<p>phMRI time courses in the CPu (a) and NAcc (b). MPH or saline challenge was administered after 12 volumes (indicated by the arrow) followed by 38 volumes post-administration. The AMPH-MPH group differed significantly from the SAL-MPH and SAL groups. Difference between pre-injection (1–12) and post-injection (15–35) displayed for the CPU and Nacc (c) for each group (mean ±SEM)* p<0.05.</p