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See detailOptimalisation de la radiosynthèse et production au niveau de la curie d'acides aminés aromatiques marqués au fluor-18
Libert, Lionel ULg

Doctoral thesis (2013)

6-[18F]fluoro-L-dopa (FDOPA) and 2-[18F]fluoro-L-tyrosine (FTYR) are useful radiopharmaceuticals for evaluation by positron emission tomography (PET) of the dopaminergic function and oncological studies ... [more ▼]

6-[18F]fluoro-L-dopa (FDOPA) and 2-[18F]fluoro-L-tyrosine (FTYR) are useful radiopharmaceuticals for evaluation by positron emission tomography (PET) of the dopaminergic function and oncological studies, respectively. In comparison to electrophilic synthesis, the no-carrier-added (nca) nucleophilic preparation of these 2 radiopharmaceuticals, described in 2004 by Lemaire et al, has several advantages such a high batch yield and high specific activity. However, this nca enantioselective synthesis using a chiral phase-transfer catalyst requires some chemicals (i.e. corrosive HBr gas) arduous to handle and store and reactions at low and high temperature (0°C, 200°C) difficult to implement into a commercially available synthesizer. Important chemical improvements, realized during this PhD thesis, having resulted in straightforward automation of FDOPA and FTYR synthesis, in a commercially available FASTLab module (GE healthcare) are presented. The first significant improvement to the synthesis has consisted in the development of a fast and reliable method suitable for the preparation of (substituted) [18F]fluorobenzyl halides from several [18F]fluorobenzaldehydes. Aromatic nucleophilic substitution of trimethylammonium benzaldehyde triflate and nitro precursors were realized with nca [18F]fluoride. After labeling, [18F]fluorobenzaldehydes were trapped on a Solid Phase Extraction (SPE) cartridge and the subsequent conversion (reduction and halogenation) into benzyl halides was directly realized, on-line, on the support. Reduction of the aldehydes and the following halogenation step were performed with an aqueous solution of NaBH4 and aqueous solutions of concentrated acid (HI, HBr, HCl), respectively. These two near-quantitative reactions proceed at room temperature within 2 minutes at high yields. The second improvement of the nca synthesis of FDOPA and FTYR has consisted in the enantioselective formation of a new carbon-carbon bond by phase-transfer catalysis in presence of a chiral phase-transfer catalyst (PTC) at RT rather than at 0°C. Seven chiral phase-transfer catalysts with a potential high enantioselectivity, at room temperature, for the asymmetric alkylation of a N-(diphenylmethylene)glycine tert-butyl ester have been prepared. Two of these catalysts affords high enantiomeric excess in FDOPA and FTYR (e.e. ≥ 95%) at room temperature and even at 75°C (e.e. ≥ 90%). One is readily available from a cinchona alkaloid and the other one from a biphenyl substrate. The third improvement concerned the hydrolysis step (200°C, 20 min). Different starting precursors with more labile protective groups than the methoxy were synthesized and evaluated. Among these compounds, the isopropyl ether protective group seems the more advantageous. By exploiting the advantages of the improvements to the chemistry described in this work and the potential of the nca approach, the synthesis of FDOPA and FTYR was automated in a FASTlab module with GMP single use cassettes. After 100 min of bombardment (167 GBq) and 63 min of synthesis, more than 50 GBq (1,35 Ci) of 6-[18F]fluoro-L-dopa (e.e. ≥ 96,3%) with a specific activity in excess of 0.75 TBq/µmol are routinely produced. For FTYR, slightly higher yield was obtained. With such reliable production, 6-[18F]fluoro-L-dopa and 2-[18F]fluoro-L-tyrosine are now available for clinical investigation. [less ▲]

Detailed reference viewed: 77 (29 ULg)
See detailOptimalisation de la valeur nutritionnelle de la graine de lupin pour les bovins
Froidmont, Eric; Bonnet, Maxime; Beckers, Yves ULg et al

in CRA-W; FUSAGx (Eds.) 12ème Carrefour des productions animales, "Le marché de la viande bovine : enjeux et perspectives" (2007, January 24)

Detailed reference viewed: 9 (0 ULg)
See detailOptimalisation des apports en acides aminés pour des taurillons BBB en complément à une ration fermière
Beckers, Yves ULg; Froidmont, Eric

Conference (2001, December 12)

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See detailOptimalisation des opérations de tournage : la méthode de la puissance disponible
Debongnie, Jean-François ULg

Report (1993)

Tailor's results on machining optimization always assume that the power of the machine tool is not a limitation. However, this not necessarily true, specially in the case of rough machining, where ... [more ▼]

Tailor's results on machining optimization always assume that the power of the machine tool is not a limitation. However, this not necessarily true, specially in the case of rough machining, where Taylorian optima are out of the power range of the machine. In this paper, an algorithm is proposed, where the machine capacity is the first consideration. The obtained result is then corrected in view of the tool life. [less ▲]

Detailed reference viewed: 50 (2 ULg)
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See detailOptimalisation des techniques prothetiques de rehabilitation orale grace a l'orthodontie: analyse d'un cas clinique.
Lies, Céline ULg; Fernandez, S.; Limme, Michel ULg et al

in Revue Médicale de Liège (2008), 63(10), 609-14

This clinical case underlines the importance of a multidisciplinary approach, prosthetic and orthodontic, for the achievement of an oral rehabilitation treatment plan. Preliminary orthodontic treatment ... [more ▼]

This clinical case underlines the importance of a multidisciplinary approach, prosthetic and orthodontic, for the achievement of an oral rehabilitation treatment plan. Preliminary orthodontic treatment has significantly improved, the position of some natural teeth, which can serve or not as a prosthetic abutment. This has produced a direct prosthetic benefit by limiting tissue reduction for preparation and by giving a better biomechanical and functional context to the restoration.Thus, after an orthodontic treatment step, lasting a year and a half, using both removable appliance and fixed appliance, prosthetic rehabilitation was possible. This included a fixed prosthesis and a removable prosthesis that gave a very satisfying an esthetic result and good masticatory function. [less ▲]

Detailed reference viewed: 230 (19 ULg)
Peer Reviewed
See detailOptimalisation du programme de la formation initiale en didactique des langues germaniques à l'Université de Liège par une meilleure articulation de la théorie et de la pratique didactiques
Simons, Germain ULg

in Bechard, J.-P.; Grégoire, D. (Eds.) Apprendre et enseigner autrement. Actes du 16e Colloque International de l'Association Internationale de Pédagogie Universitaire (1999)

Detailed reference viewed: 5 (2 ULg)
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See detailOptimaliser les systèmes de production des bioressources
Delaplace, Pierre ULg

Scientific conference (2013, May 07)

Detailed reference viewed: 20 (2 ULg)
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Peer Reviewed
See detailOptimality of feeding on land versus in water in juvenile Alpine newts (Triturus alpestris veluchiensis)
Denoël, Mathieu ULg

Poster (2005)

Most newts experience both terrestrial and aquatic environments during their adult life. A large number of studies explored the feeding habits in the aquatic habitat while very few focused on the ... [more ▼]

Most newts experience both terrestrial and aquatic environments during their adult life. A large number of studies explored the feeding habits in the aquatic habitat while very few focused on the terrestrial component and none compared the two systems within a single population. The aim of this study was to find out which foraging tactic is the most successful in terms of energy intake. To this end, I analysed the feeding habits of metamorphosed juveniles in the Alpine newt inhabiting a Greek alpine lake and its surrounding lands. The diet reflected the range of prey available in the two habitats, but invertebrates, which fell on the water surface, were also ingested by aquatic newts. These two lifestyles had different energy outcomes because the highest number of terrestrial invertebrates taken in the terrestrial habitat than in the aquatic one provided higher energy gains to terrestrial juveniles. However, different mortality rates between habitats (highest probability of freezing risk on high-elevated lands than in deep waters) and an expected lower energy intake on land when air temperature is low could explain the persistence of the aquatic foraging tactic in the population. [less ▲]

Detailed reference viewed: 23 (1 ULg)
See detailOptimalization of green note aldehydes production by a hydroperoxide lyase
Fauconnier, Marie-Laure ULg; Chot, C. E.; Marlier, M.

Poster (1996, September 26)

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See detailOptimally Locating Facilities with Variable Characteristics
Kucukaydin, Hande ULg

Doctoral thesis (2011)

Facility location problems aim at optimally locating facilities like plants, warehouses, convenience stores, shopping malls etc. They can have different objectives such as maximizing the profit gained ... [more ▼]

Facility location problems aim at optimally locating facilities like plants, warehouses, convenience stores, shopping malls etc. They can have different objectives such as maximizing the profit gained from the customers or minimizing the costs of locating facilities and serving the customers. In this thesis, we mainly focus on competitive facility location problems which constitute a special family. In a competitive facility location problem, a firm or franchise is concerned with installing new facilities to serve customers in a market where existing facilities with known locations and attractiveness levels compete for increasing their market share and profit. We can classify these problems into two groups: those with non-reactive competition and those with reactive competition. Three different types of competitive facility location models are proposed in order to determine the locations and attractiveness levels of the new facilities to maximize the profit in this thesis. The first one belongs to the former class, where the last two models fall into the latter one. We formulate the first one as a mixed-integer nonlinear programming problem and propose three methods for its solution: a Lagrangean heuristic, a branch-and-bound method with Lagrangean relaxation, and a branch-and-bound method with nonlinear programming relaxation. The computational results obtained on a set of problem instances show that the branch-and-bound method using nonlinear programming relaxation is the most efficient and accurate solution method in order to solve the proposed problem. We consider next an extension of this model by relaxing the assumption that the competitor in the market does not react to the opening of new facilities. In other words, the competitor can react by adjusting the attractiveness levels of its existing facilities with the objective of maximizing its own profit. To this end, a bilevel mixed-integer nonlinear programming model is formulated. We transform this bilevel model into an equivalent one-level mixed-integer nonlinear program and solve it by a global optimization method. For this problem, we also consider a scenario in which the new entrant firm ignores the reaction of the competitor. The experimental results indicate that anticipating the competitor's reaction by including this into his optimization problem increases the profit of the new entrant firm, whereas the competitor's profit is decreased. The last competitive facility location model relaxes the limitation about the competitor's reaction: now the competitor can also open new facilities, close existing ones and/or adjust their attractiveness. This also formulates a bilevel mixed-integer nonlinear programming problem which we try to solve by combining tabu search with global optimization algorithms. We develop three different tabu search methods and the computational results on a set of problem instances for comparing the performance of the solution methods show that the third tabu search method is the most accurate one, while the second tabu search method is the most efficient solution procedure. Finally, we consider a different facility location problem which takes the customer preferences into account. The facilities are not necessarily identical and customers visit different types of facilities according to some given probability distribution and the maximum distance which they are willing to travel. We formulate a binary linear programming problem and solve it by three procedures that include a Lagrangean heuristic whose solution is improved further using a local search method. Based on the experimental results carried out on a set of problem instances the third solution method is the most efficient one. However, a statistical analysis on the quality of the solutions states that there is no significant difference between the three solution procedures. [less ▲]

Detailed reference viewed: 64 (14 ULg)
See detailOptimally Locating Facilities with Variable Characteristics
Kucukaydin, Hande ULg; Altinel, I. Kuban; Aras, Necati

Book published by LAP Lambert Academic Publishing (2012)

The main focus of this study is on competitive facility location problems which constitute a special family of facility location problems. In such a problem, a firm or franchise is concerned with ... [more ▼]

The main focus of this study is on competitive facility location problems which constitute a special family of facility location problems. In such a problem, a firm or franchise is concerned with installing new facilities to serve customers in a market where existing facilities with known locations and attractiveness levels compete for increasing their market share and profit. We can classify these problems into two groups: those with non-reactive competition and those with reactive competition. In this study, three different types of competitive facility location models are proposed in order to determine the locations and attractiveness levels of the new facilities to maximize the profit. The first one belongs to the former class, where the last two models fall into the latter one and therefore bring us to the area of the bilevel programming. Finally, a different facility location problem which takes the customer preferences into account is considered, where the facilities are not necessarily identical and customers visit different types of facilities according to some given probability distribution and the maximum distance which they are willing to travel. [less ▲]

Detailed reference viewed: 23 (5 ULg)
See detailOptimieren Sie ihr Haus
Guillemeau, Jean-Marc ULg; Hauglustaine, Jean-Marie ULg; Wagelmans, Paul ULg

Book (2003)

This booklet is intended to inform each and everyone on the possibilities of optimizing its dwelling, in the observance of the thermal regulation of the Walloon region: since the choice of the ground ... [more ▼]

This booklet is intended to inform each and everyone on the possibilities of optimizing its dwelling, in the observance of the thermal regulation of the Walloon region: since the choice of the ground until the precautions of implementation. [less ▲]

Detailed reference viewed: 30 (6 ULg)
See detailOptimiertes Design von Drehscheibenextraktoren
Aksamija, E; Prieler, R; Zörweg, K et al

in Book of Abstracts zum 8. Minisymposium der Verfahrenstechnik, 3-4 (2012, May 02)

See detailOptimierung der Modellierung von Extraktionskolonnen anhand von verbesserten Einzeltropfenversuchen
Cvetkovic, E; Bol, J B; Pfennig, Andreas ULg

Conference (2014)

Detailed reference viewed: 12 (0 ULg)
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See detailOptimierung von experimentellen Bedingungen f�r die Reaktiv- und Phytoextraktion
Delinski, Dirk; Kalem, Murat; Bertakis, Evangelos et al

in Chemie Ingenieur Technik (2009)

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See detailOptiMIR : de nouveaux outils de management des exploitations laitières grâce au spectre moyen infra-rouge du lait
Grelet, Clément ULg; Fernandez Pierna, Juan Antonio; Dehareng, Frédéric et al

Conference (2013)

Detailed reference viewed: 15 (3 ULg)
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See detailOptiMIR- Développement et mise en place d'outils innovants de gestion des troupeaux et de conseil personnalisé pour une meilleure durabilité du secteur laitier
Hammami, Hedi ULg; Massart, Xavier; Bertozzi, Carlo et al

in 16ème Carrefour des Productions animales: La filière laitière bovine européenne est-elle durable? (2011, March)

Detailed reference viewed: 51 (8 ULg)