8 research outputs found
Structure and separation quality of various N- and O-donor ligands from quantum-chemical calculations
Although BTP (2,6-di(1,2,4-triazin-3-yl)pyridine) has been proven to be a highly effective N-donor ligand for the selective An(III)/Ln(III) separation, the origin of its selectivity is still under discussion. We present in this paper quantum-chemical calculations at the density functional theory (DFT) and MP2 level which highlight the role of the aquo ions in the separation process. Furthermore these data will be the reference for future force-field development to investigate the differences in An(III) complexation reactions compared to their Ln(III) counterparts
Towards reliable modeling of excited states of uranium compounds
Visscher, L. [Promotor
Annual Report 2013 / Institute for Nuclear Waste Disposal. (KIT Scientific Reports ; 7664)
The contributions collected in this report provide a representative overview of the scientific outcome of INE research activities in 2013. The structure of the report follows widely the organization of the institute according to research topics: basic research towards understanding geochemical reactions of radionuclides on a molecular scale and applied studies on radionuclide retention in multi-barrier system under real repository conditions
New Building Blocks for Cancer Phototherapeutics: 5d Metallocorroles
Corroles are ring-contracted, triprotic analogues of porphyrins. This PhD study expands earlier knowledge in particular on ReO corroles. Early on, it became apparent that ReO corroles exhibit the highest phosphorescence quantum yields among all metallocorroles. They also sensitize singlet oxygen formation and serve as oxygen sensors and as triplet-triplet annihilation upconverters. I accordingly wanted to synthesize new classes of functionalized 5d corroles as well as to examine ReO corroles as photosensitizers in in vitro photodynamic therapy experiments. I found that amphiphilic meta/para-carboxyl-appended ReO triphenylcorroles exhibit high photocytotoxicity against multiple cancer cell lines. In the synthetic realm, one study examined electrophilic chlorination and bromination of ReO corroles. X-ray structures of ReO octachloro- and octabromocorroles yielded a host of insights into the conformational preferences of sterically hindered corrole derivatives. Another synthetic study afforded an innovative approach to water-soluble iridium corroles, involving the use of water-soluble axial ligands. I also undertook extensive studies of formylation of ReO and Au triarylcorroles, arriving at the rather elegant conclusion that whereas the former largely afford 3-monoformyl products, the latter preferentially yield 3,17-diformylproducts, presumably reflecting the higher nucleophilicity of the Au complexes. The formylcorrole products could be readily postfunctionalized, such as via the Knoevenagel reaction. The 5d formylcorroles should serve as valuable starting materials for bio- and nanoconjugated 5d metallocorroles for advanced, targeted cancer therapies. I feel privileged to have developed a new class of triplet photosensitizers â the ReO corroles â that to this day remain unique to our TromsĂž laboratory. I am confident, however, that we shall soon see exciting applications of these compounds as advanced photodynamic, photothermal and multimodal cancer therapeutics
Further insights in the ability of classical nonadditive potentials to model actinide ion-water interactions
13 pagesInternational audiencePursuing our efforts on the development of accurate classical models to simulate radionuclides in complex environments (RĂ©al et al., J. Phys. Chem. A 2010, 114, 15913; Trumm et al. J. Chem. Phys. 2012, 136, 044509), this article places a large emphasis on the discussion of the influence of models/parameters uncertainties on the computed structural, dynamical, and temporal properties. Two actinide test cases, trivalent curium and tetravalent thorium, have been studied with three different potential energy functions, which allow us to account for the polarization and charge-transfer effects occurring in hydrated actinide ion systems. The first type of models considers only an additive energy term for modeling ion/water charge-transfer effects, whereas the other two treat cooperative charge-transfer interactions with two different analytical expressions. Model parameters are assigned to reproduce high-level ab initio data concerning only hydrated ion species in gas phase. For the two types of cooperative charge-transfer models, we define two sets of parameters allowing or not to cancel out possible errors inherent to the force field used to model water/water interactions at the ion vicinity. We define thus five different models to characterize the solvation of each ion. For both ions, our cooperative charge-transfer models lead to close results in terms of structure in solution: the coordination number is included within 8 and 9, and the mean ion/water oxygen distances are 2.45 and 2.49 Ă
, respectively, for Th(IV) and Cm(III
Combiner approches statique et dynamique pour modéliser la performance de boucles HPC
The complexity of CPUs has increased considerably since their beginnings, introducing mechanisms such as register renaming, out-of-order execution, vectorization,prefetchers and multi-core environments to keep performance rising with each product generation. However, so has the difficulty in making proper use of all these mechanisms, or even evaluating whether oneâs program makes good use of a machine,whether usersâ needs match a CPUâs design, or, for CPU architects, knowing how each feature really affects customers.This thesis focuses on increasing the observability of potential bottlenecks inHPC computational loops and how they relate to each other in modern microarchitectures.We will first introduce a framework combining CQA and DECAN (respectively static and dynamic analysis tools) to get detailed performance metrics on smallcodelets in various execution scenarios.We will then present PAMDA, a performance analysis methodology leveraging elements obtained from codelet analysis to detect potential performance problems in HPC applications and help resolve them. A work extending the Cape linear model to better cover Sandy Bridge and give it more flexibility for HW/SW codesign purposes will also be described. It will bedirectly used in VP3, a tool evaluating the performance gains vectorizing loops could provide.Finally, we will describe UFS, an approach combining static analysis and cycle accurate simulation to very quickly estimate a loopâs execution time while accounting for out-of-order limitations in modern CPUsLa complexitĂ© des CPUs sâest accrue considĂ©rablement depuis leurs dĂ©buts, introduisant des mĂ©canismes comme le renommage de registres, lâexĂ©cution dans le dĂ©sordre, la vectorisation, les prĂ©fetchers et les environnements multi-coeurs pour amĂ©liorer les performances avec chaque nouvelle gĂ©nĂ©ration de processeurs. Cependant, la difficultĂ© a suivi la mĂȘme tendance pour ce qui est a) dâutiliser ces mĂȘmes mĂ©canismes Ă leur plein potentiel, b) dâĂ©valuer si un programme utilise une machine correctement, ou c) de savoir si le design dâun processeur rĂ©pond bien aux besoins des utilisateurs.Cette thĂšse porte sur lâamĂ©lioration de lâobservabilitĂ© des facteurs limitants dans les boucles de calcul intensif, ainsi que leurs interactions au sein de microarchitectures modernes.Nous introduirons dâabord un framework combinant CQA et DECAN (des outils dâanalyse respectivement statique et dynamique) pour obtenir des mĂ©triques dĂ©taillĂ©es de performance sur des petits codelets et dans divers scĂ©narios dâexĂ©cution.Nous prĂ©senterons ensuite PAMDA, une mĂ©thodologie dâanalyse de performance tirant partie de lâanalyse de codelets pour dĂ©tecter dâĂ©ventuels problĂšmes de performance dans des applications de calcul Ă haute performance et en guider la rĂ©solution.Un travail permettant au modĂšle linĂ©aire Cape de couvrir la microarchitecture Sandy Bridge de façon dĂ©taillĂ©e sera dĂ©crit, lui donnant plus de flexibilitĂ© pour effectuer du codesign matĂ©riel / logiciel. Il sera mis en pratique dans VP3, un outil Ă©valuant les gains de performance atteignables en vectorisant des boucles.Nous dĂ©crirons finalement UFS, une approche combinant analyse statique et simulation au cycle prĂšs pour permettre lâestimation rapide du temps dâexĂ©cution dâune boucle en prenant en compte certaines des limites de lâexĂ©cution en dĂ©sordre dans des microarchitectures moderne