Production of viable hybrids in salmonids by triploidization

Rainbow trout eggs were fertilized with milt collected from various salmanids (brown trout Salmo trutta ; brook trout Salvelinus lontinaliv ; coho salmon Oncorhynchus kisutch) and heat-shocked few minutes later in order to prevent the second polar body extrusion. This operation resulted in high survival rates after 161 days : respectively 49.2 p. 100, 66.2 p. 100 and 12.5 p. 100 of the diploid rainbow trout control (basis 100 p. 100) ; the triploid hybrid constitution of these fish was ascertained by karyological and biochemical investigations. These data contrast with the bad yields of the corresponding diploid hybridizations (no heat shock) respectively 0 p. 100, 12.3 p. 100 and 0 p. 100. Such triploid hybrid salmonids, that are easy to produce, could be sterile and consequently of a great interest in aquaculture, where fish reproduction often makes the profitability decrease.Des ovules de truite arc-en-ciel Salmo gairdneri ont été inséminés par du sperme de divers salmonidés (truite fario Salmo trutta; omble de fontaine Salvelinus fontinalis; saumon coho Oncorhynchus kisurch) puis soumis à un choc thermique chaud induisant la rétention du 2e globule polaire. Des individus viables ont été obtenus à un taux élevé : les taux de survie à 161 jours rapportés au témoin diploïde arc-en-ciel s’élèvent respectivement à 49,2 p. 100, 66,2 p. 100 et 12,5 p. 100. Les données caryologiques et biochimiques indiquent que tous ces animaux sont des hybrides triploïdes. Par contre, les mêmes croisements non soumis à un choc chaud ne produisent qu’un très faible nombre de survivants (respectivement 0 p. 100, 12,3 p. 100, 0 p. 100) identifiés comme des hybrides diploïdes. Compte tenu de leur facilité d’obtention, les hybrides triploïdes peuvent se révéler des animaux intéressants pour l’aquaculture, du fait notamment de leur éventuelle stérilité

Covalent vs. non-covalent redox functionalization of C-LiFePO4 based electrodes

During high rate utilization of porous Li battery, Li+ refuelling from the electrolyte limits the discharge kinetics of positive electrodes. In the case of thick electrodes a strategy to buffer the resulting sharp drop of Li+ concentration gradient would be to functionalize the electrode with anionic based redox molecules (RMR) that would be therefore able to relay intercalation process. The occurrence of these RMR in the electrode should not however, induce adverse effect on Li intercalation processes. In this respect, this work studies the effect of functionalizing LFPC based electrodes by either covalent or non-covalent chemistry, on Li intercalation kinetics. To do so, model molecules containing a nitro group were introduced at the surface of both carbon conducting additives and active material (C-LiFePO4). It is shown that presumably due to formation of sp(3) defects, covalent anchoring using diazonium chemistry inhibits the intercalation kinetics in C-FePO4. On the contrary, if molecules such as pyrene derivatives are immobilized by pi-staking interactions, Li intercalation is not impeded. Therefore non-covalent functionalization of pyrene based RMR appears as a promising route to relay Li intercalation reaction during high power demand. The framework for future development of this strategy is discussed. (C) 2013 Elsevier B.V. All rights reserved

New Concept to Boost Energy and Power Peformance of Practical Electrochemical Devices

International audienc

Optimization of Electronic Transport at the Nanoscale through the Formation of Molecular Junctions within Composite Electrodes for Li-battery

National audienc

In situ redox functionalization of composite electrodes for high power-high energy electrochemical storage systems via a non-covalent approach

The growing demand for new global resources of clean and sustainable energy emerges as the greatest challenge in today\u27s society. For numerous applications such as hybrid vehicles, electrochemical storage systems simultaneously require high energy and high power. For this reason, intensive researches focus on proposing alternative devices to conventional Li battery and supercapacitors. Here, we report a proof of concept based on non-covalent redox functionalization of composite electrodes that may occur either during the calendar life or during the device functioning. The active material, a multi-redox pyrene derivative, is initially contained in the electrolyte. No additional benchmarking step is therefore required, and it can, in principle, be readily applied to any type of composite electrode (supercapacitors, battery, semi-solid flow cell etc.). Accordingly, a practical carbon fiber electrode that is 10 mg cm(-2) loaded can deliver up to 130 kW kg(electrode)(-1) and 130 Wh kg(electrode)(-1) with negligible capacity loss over the first 60 000 charge/discharge cycles