Échographie du cristallin du chien : étude bibliographique

L'échographie oculaire est une technique de plus en plus utilisée en médecine vétérinaire. Après de brefs rappels sur la technique de l'échographie, l'examen échographique du globe oculaire est envisagé. L'anatomie échographique normale du cristallin est par la suite décrite, ainsi que les principales variations physiologiques. Ce sont ensuite les différentes anomalies pathologiques qui sont envisagées, les indications de l'examen échographique dans ce contexte pathologique et enfin l'aspect des images. Ainsi sont tour à tour décrites les anomalies congénitales (aphakie, microphakie, lenticône postérieur, persistance du vitré primitif), les cataractes, les luxations du cristallin et enfin les traumatismes du globe oculaire

Identification des contributions enthalpiques a l'origine de la sélectivité en extraction liquide/liquide

International audienc

Effect of the Structure of Amido-polynitrogen Molecules on the Complexation of Actinides

AbstractThe complexation and solvent extraction of Eu(III) and actinides in different oxidation states (Am(III), Pu(IV), Np(V)) by bitopic molecules with a dipyridyl-phenanthroline cycle as nitrogen unit and one or two amido functions are described. The complexation has been studied in methanol-water solution with hydrophilic molecules to enhance knowledge about this new family of ligands and to identify the most interesting structural effect. Some extraction tests have been performed with lipophilic molecules of the family to check the possible utility of the new class of ligands under representative fuel reprocessing conditions. These first studies have demonstrated that the presence of a preorganized N-donors unit like dipyridyl-phenanthroline improves the ligand's affinity for actinides and its An/Ln selectivity

[2-Amino-4,6-bis­(2-pyrid­yl)-1,3,5-tri­azine-κ3 N 4,N 5,N 6]dichloridocadmium(II)

In the title compound, [CdCl2(C13H10N6)], the 2-amino-4,6-bis(pyridin-2-yl)-1,3,5-triazine (HABPT) ligand adopts a tridentate tripyridyl coordination mode. The CdII atom is five-coordinated by three N atoms from the HABPT ligand and two chloride ions. In the crystal, mol­ecules are linked via N—H⋯N, N—H⋯Cl and C—H⋯Cl hydrogen bonds into a supra­molecular network

Modeling and Flowsheet Design of an Am Separation Process Using TODGA and H₄TPAEN

Recycling americium from spent fuels is an important consideration for the future nuclear fuel cycle, as americium is the main contributor to the long-term radiotoxicity and heat power of the final waste, after separation of uranium and plutonium using the PUREX process. The separation of americium alone from a PUREX raffinate can be achieved by co-extracting lanthanide (Ln(III)) and actinide (An(III)) cations into an organic phase containing the diglycolamide extractant TODGA, and then stripping Am(III) with selectivity towards Cm(III) and lanthanides. The water soluble ligand H4TPAEN was tested to selectively strip Am from a loaded organic phase. Based on experimental data obtained by Jülich, NNL and CEA laboratories since 2013, a phenomenological model has been developed to simulate the behavior of americium, curium and lanthanides during their extraction by TODGA and their complexation by H4TPAEN (complex stoichiometry, extraction and complexation constants, kinetics). The model was gradually implemented in the PAREX code and helped to narrow down the best operating conditions. Thus, the following modifications of initial operating conditions were proposed: • An increase in the concentration of TPAEN as much as the solubility limit allows. • An improvement of the lanthanide scrubbing from the americium flow by adding nitrates to the aqueous phase. A qualification of the model was begun by comparing on the one hand constants determined with the model to those measured experimentally, and on the other hand, simulation results and experimental data on new independent batch experiments. A first sensitivity analysis identified which parameter has the most dominant effect on the process. A flowsheet was proposed for a spiked test in centrifugal contactors performed with a simulated PUREX raffinate with trace amounts of Am and Cm. If the feasibility of the process is confirmed, the results of this test will be used to consolidate the model and to design a flowsheet for a test on a genuine PUREX raffinate. This work is the result of collaborations in the framework of the SACSESS European Project

Modeling and Flowsheet Design of an Am Separation Process Using TODGA and H₄TPAEN

Recycling americium from spent fuels is an important consideration for the future nuclear fuel cycle, as americium is the main contributor to the long-term radiotoxicity and heat power of the final waste, after separation of uranium and plutonium using the PUREX process. The separation of americium alone from a PUREX raffinate can be achieved by co-extracting lanthanide (Ln(III)) and actinide (An(III)) cations into an organic phase containing the diglycolamide extractant TODGA, and then stripping Am(III) with selectivity towards Cm(III) and lanthanides. The water soluble ligand H4TPAEN was tested to selectively strip Am from a loaded organic phase. Based on experimental data obtained by Jülich, NNL and CEA laboratories since 2013, a phenomenological model has been developed to simulate the behavior of americium, curium and lanthanides during their extraction by TODGA and their complexation by H4TPAEN (complex stoichiometry, extraction and complexation constants, kinetics). The model was gradually implemented in the PAREX code and helped to narrow down the best operating conditions. Thus, the following modifications of initial operating conditions were proposed: • An increase in the concentration of TPAEN as much as the solubility limit allows. • An improvement of the lanthanide scrubbing from the americium flow by adding nitrates to the aqueous phase. A qualification of the model was begun by comparing on the one hand constants determined with the model to those measured experimentally, and on the other hand, simulation results and experimental data on new independent batch experiments. A first sensitivity analysis identified which parameter has the most dominant effect on the process. A flowsheet was proposed for a spiked test in centrifugal contactors performed with a simulated PUREX raffinate with trace amounts of Am and Cm. If the feasibility of the process is confirmed, the results of this test will be used to consolidate the model and to design a flowsheet for a test on a genuine PUREX raffinate. This work is the result of collaborations in the framework of the SACSESS European Project

Effects of Gamma Irradiation on the Extraction Properties of Innovative Stripping Solvents for i-SANEX/GANEX Processes

Recovery of trivalent minor actinides or of the transuranium elements from highly active raffinate could be industrially achieved by innovative Selective ActiNide EXtraction (i-SANEX) and Grouped ActiNide EXtraction (GANEX) processes, respectively. All chemicals involved in the partitioning of actinides must be resistant to acidic and radioactive environments since hydrolysis and radiolysis can have a huge impact on process safety and performance. In this work, the hydrolytic and radiolytic stabilities of two innovative hydrophilic complexing agents, 2,6-bis[1-(propan-1-ol)-triazolyl]pyridine and 2,6-bis[1-(propan-1,2-diol-triazolyl)]pyridine, have been investigated as they proved to be endowed with high actinide selectivity. In order to simulate the damage experienced under process conditions, the stripping solutions were aged in HNO3 for several weeks and γ-irradiated up to 200 kGy with 60Co sources. Batch liquid-liquid extraction tests were performed on fresh, aged, and irradiated stripping solutions in order to verify whether aging and γ-irradiation affect system performance. Furthermore, nuclear magnetic resonance (NMR) analyses were carried out to ascertain the radiation-induced ligand degradation and subsequent byproduct formation. The stripping solutions manifested exceptional performance and radiochemical stability, even under harsh process conditions, to demonstrate their industrial applicability to i-SANEX and GANEX processes

Une nouvelle forme symptomatologique du court noué de la vigne ? Qui a vu celà ?

National audienc