Evaluation of transgenic Prunus domestica L., clone C5 resistance to Plum pox virus

Plum pox virus (PPV) is one of the most devastating diseases of Prunus species. Since few sources of resistance to PPV have been identified, transgene-based resistance offers a complementary approach to developing PPV-resistant stone fruit cultivars. C5, a transgenic clone of Prunus domestica L., containing the PPV coat protein (CP) gene, has been described as highly resistant to PPV in greenhouse tests, displaying characteristics typical of post-transcriptional gene silencing (PTGS). Moreover, C5 trees exposed to natural aphid vectors in the field remained uninfected after 4 years while susceptible transgenic and untransformed trees developed severe symptoms within the first year. In our study, a high and permanent infection pressure of PPV was provided by bud grafting of inoculum in the field trial of clone C5 conducted in the Czech Republic, in which PPV-infected and healthy control trees were used. Moreover, trees with combined inoculations by PPV, ACLSV and PDV were also used in the trial. The presence of the viruses throughout the tree tissues, the relative titre of the viruses and symptoms on C5 trees have been monitored over the years. The resistance stability of C5 clones under permanent infection pressure is discussed.Keywords: PPV, C5, resistance, real-time PC

The synthesis of SiC and TiC protective coatings for carbon fibers by the reactive replica process

International audienc

Étude de la capture du cadmium par des adsorbants à haute température

Because of its importance in incineration plants, the interaction of heavy metals with various sorbents has recently lead to a great amount of work. Most of these studies were performed with fixed bed or thermogravimetric apparatus and it is often difficult to correlate the results of these experiments with incineration flue gas conditions. The GRE laboratory has developed a drop tube furnace in order to quantify the adsorption of cadmium chloride on different sorbents in conditions representative of incinerators : short contact time, low concentrations of metal vapour and metal, high temperature. A study of the adsorption of cadmium chloride onvarious sorbents has been done. Alumina and calciumoxide were found to be more effective for cadmiumcapture than silica or alumino silica. The leachable fraction of cadmium on each sorbent appears to be very low. The influence of sorbent surface area, gas temperature, and metal vapour concentration was studied. Du fait de son importance dans les processus d’incinération, l’interaction entre les métaux et les solides susceptibles d’être présents dans les fumées d’incinération a donné lieu à un grand nombre d’études. Cependant, la plupart d’entre elles ont été faites à l’aide de lits fixes et il est souvent difficile de corréler les résultats avec ce qui est observé dans les fumées d’incinérateurs. Le laboratoire de gestion des risques et environnement a conçu un four à chute qui permet de quantifier la quantité de métal adsorbée dans des conditions proches de celles observées dans un incinérateur : temps de séjour faible, concentrations en vapeur métallique et en solide faibles, hautes températures. Une étude de l’adsorption du chlorure de cadmium sur différents solides minéraux a été effectuée. Il a été observé que l’alumine et la chaux sont plus efficaces que la silice ou l’aluminosilicate. Dans tous les cas, la fraction lixiviable est très faible. L’influence de la texture de l’adsorbant et de la température du milieu gazeux a aussi été étudiée

KOH activated carbon multiwalled nanotubes

International audienc

The effects of textural modifications on beech wood-char gasification rate under alternate atmospheres of CO2 and H2O

International audienceDespite the huge literature on biomass char gasification with CO2 or H2O, ambiguity still hovers over the issue of char gasification in complex atmospheres. Gas alternation gasification experiments, in which the reacting gas is changed during the reaction, were performed with CO2/H2O at 900 degrees C for small (200 mu m) and large (13 mm) Low Heating Rate (LHR) beech wood char particles to assess the potential influences that CO2 and H2O can have on each other during the char gasification reaction. The results showed no influence of a first gasification atmosphere on the char reactivity under the second one. The char reactivity to a specific gas at a certain conversion level was the same as if the gasification reaction was operated from the beginning with the same atmosphere composition. The purpose of this paper is to bring understanding keys to this lack of influence of previous gasification conditions on the char reactivity. Characterization of the chars throughout the conversion by measuring the total surface area and the active surface area was first performed. Then a transport limitation analysis based on the Thiele modulus was considered. It was concluded that the two gasses develop different porosities in the char, however, the Thiele modeling results and active surface area analysis indicate respectively that gasses diffuse preferentially in large macro-pores and that the concentration of active sites evolves similarly during both gasification reactions. This similarity in the diffusion mechanism as well as in the evolution of the concentration of active sites could be a plausible explanation for the only-dependent conversion reactivity observed in the gas alternation gasification experiments

The formation and reduction of NO during the combustion of powdered petroleum coke - The case of cement plant precalciner conditions

In a cement plant precalciner, petroleum cokes are burned between 800 and 1100°C and NO present in the flue gas is mainly fuel NO. We have developed a thermochemical model that describes the combustion of powdered petroleum coke in laminar flow conditions. It takes into account the main thermal and chemical mechanisms which occur during combustion. The formation and reduction mechanisms for fuel, prompt, and thermal NO are modeled; as far as gas-phase reactions are concerned, detailed chemistry is treated. Specific experiments were conducted to characterize the species produced by each of the major reactions and to determine their reaction kinetics. These experiments were performed in an entrained-flow reactor at 900°C under conditions typical of those in a precalciner. A gas analysis device based on high-resolution Fourier transform infrared was specifically developed to quantify the main gases which participate in NO formation and destruction. Thanks to this work, the main mechanisms were distinguished, and their relative importance in NO formation was established. Gas-phase reactions form most of the NO in the flame zone but contribute only slightly to the final NO emission. The quantity of thermal NO is negligible. Fuel NO is formed principally during combustion of the carbon residue. In compensation, a significant quantity of NO is reduced by heterogeneous reaction with the carbon of the particles. (Résumé d'auteur

Adsorption de micropolluants sur tissus et feutres de carbone activé

National audienc