Layer-by-Layer Assembled Nanowire Networks Enable Graph Theoretical Design of Multifunctional Coatings

Multifunctional coatings are central for information, biomedical, transportation and energy technologies. These coatings must possess hard-to-attain properties and be scalable, adaptable, and sustainable, which makes layer-by-layer assembly (LBL) of nanomaterials uniquely suitable for these technologies. What remains largely unexplored is that LBL enables computational methodologies for structural design of these composites. Utilizing silver nanowires (NWs), we develop and validate a graph theoretical (GT) description of their LBL composites. GT successfully describes the multilayer structure with nonrandom disorder and enables simultaneous rapid assessment of several properties of electrical conductivity, electromagnetic transparency, and anisotropy. GT models for property assessment can be rapidly validated due to (1) quasi-2D confinement of NWs and (2) accurate microscopy data for stochastic organization of the NW networks. We finally show that spray-assisted LBL offers direct translation of the GT-based design of composite coatings to additive, scalable manufacturing of drone wings with straightforward extensions to other technologies

Food contact material for baking: a review on associated chemical risks and technological issues

This article presents an overview on product contact surfaces (PCS) used for baking supports, with a focus on associated neoformed and exogenous contaminants related to these PCSs in the case of baking. Exogenous contaminants are usually brought into the product from the surface contact material of the baking support, and in particular, from antistick coatings (ASC). Due to multiple thermal treatments, the performance of ASCs evolve during ageing, resulting in sticking problems. In addition, there is no European regulation in force to track associated chemical risks. Two main types of ASC material are used: perfluorinated and silicone based ASC. Sticking of bakery products during baking is linked to various aspects such as recipe, baking temperature, the use (or not) of antistick fluids, etc. For instance, silicone coatings are preferred to perfluorinated coatings for yellow dough. Some products, such as biscuits, can be baked directly on steel. A limited amount of literature exists on the risk of chemical transfer from either fluorinated or silicone based coatings to the food. Highly sensitive measurement methods based on liquid chromatograpy coupled to tandem mass spectometry (LC-MS/MS) and/or liquid chromatography-high resolution mass spectrometry (LC-HRMS) have been used for the determination of 13 perfluorinated compounds (including perfluorooctane sulfonate anion (PFOS) and perfluorooctanoic acid (PFOA) in water and pancakes cooked in contact with ASC. Preliminary results (not shown) indicated that contamination was below the regulation threshold when using new cookware equipment (frying pan). Two other PCSs used in baking, aluminium and baking paper, and their associated chemical risks are discussed. Neoformed contaminants are usually due to reactions between inoffensive precursors, which result from the interaction between these precursors and the matrix. The impact of the thermal treatment combined with the evolution of other physical parameters (e.g., moisture, pH, etc.) may result in the formation of neoformed contaminants. The case of the Maillard reaction compounds (MRCs) and of the 3-chloro-1,2-propanediol (3-MCPD) esters and the impact of the pH on those contaminants is discussed. Finally, the technological problem of sticking seems to be closely linked to the condition of the product contact surface, and thus indirectly linked to a higher risk of transfer of exogenous contaminants into the product. Therefore, it appears advisible to develop tools and protocols to assess the condition of baking support undergoing multiple thermal cycles for the benefit of the industry and of the health of consumers.JRC.I.1-Chemical Assessment and Testin

Neuroprotective effects of a brain permeant 6-aminoquinoxaline derivative in cell culture conditions that model the loss of dopaminergic neurons in Parkinson disease.

International audienceParkinson disease is a neurodegenerative disorder of aging, characterized by disabling motor symptoms resulting from the loss of midbrain dopaminergic neurons and the decrease of dopamine in the striatum. Current therapies are directed at treating the symptoms but there is presently no cure for the disease. In order to discover neuroprotective compounds with a therapeutical potential, our research team has established original and highly regioselective methods for the synthesis of 2,3-disubstituted 6-aminoquinoxalines. To evaluate the neuroprotective activity of these molecules, we used midbrain cultures and various experimental conditions that promote dopaminergic cell loss. Among a series of 11 molecules, only compound MPAQ (2-methyl-3-phenyl-6-aminoquinoxaline) afforded substantial protection in a paradigm where dopaminergic neurons die spontaneously and progressively as they mature. Prediction of blood-brain barrier permeation by Quantitative Structure-Activity Relationship studies (QSARs) suggested that MPAQ was able to reach the brain parenchyma with sufficient efficacy. HPLC-MS/MS quantification in brain homogenates and MALDI-TOF mass spectrometry imaging on brain tissue sections performed in MPAQ-treated mice allowed us to confirm this prediction and to demonstrate, by MALDI-TOF mass spectrometry imaging, that MPAQ was localized in areas containing vulnerable neurons and/or their terminals. Of interest, MPAQ also rescued dopaminergic neurons, which (i) acquired dependency on the trophic peptide GDNF for their survival or (ii) underwent oxidative stress-mediated insults mediated by catalytically active iron. In summary, MPAQ possesses an interesting pharmacological profile as it penetrates the brain parenchyma and counteracts mechanisms possibly contributive to dopaminergic cell death in Parkinson disease

Impact of Inhaled Nitric Oxide on the Sulfatide Profile of Neonatal Rat Brain Studied by TOF-SIMS Imaging

Despite advances in neonatal intensive care leading to an increased survival rate in preterm infants, brain lesions and subsequent neurological handicaps following preterm birth remain a critical issue. To prevent brain injury and/or enhance repair, one of the most promising therapies investigated in preclinical models is inhaled nitric oxide (iNO). We have assessed the effect of this therapy on brain lipid content in air- and iNO-exposed rat pups by mass spectrometry imaging using a time-of-flight secondary ion mass spectrometry (TOF-SIMS) method. This technique was used to map the variations in lipid composition of the rat brain and, particularly, of the white matter. Triplicate analysis showed a significant increase of sulfatides (25%–50%) in the white matter on Day 10 of life in iNO-exposed animals from Day 0–7 of life. These robust, repeatable and semi-quantitative data demonstrate a potent effect of iNO at the molecular level