Résultats de recherche

Jury Prof. Benoît CHAMPAGNE (UNamur), présidentProf. Carmela APRILE (UNamur), secrétaireProf. Eric GAIGNEAUX (UCLouvain)Prof. Sonia FIORILLI (Politecnico di Torino)Prof. Wouter MARCHAL (UHasselt) Abstract Heterogeneous acid catalysts became over the years essential to our modern industrial world. Among the possible forms of solid materials with acidic properties, porous silica-based structures embedding active single-sites showed highly promising catalytic activity for various reactions. The insertion of heteroelements inside the SiO2 network is known to introduce a combination of Brønsted and Lewis acid sites which depends on the nature of the element and influences the catalytic properties of the solid. The present thesis investigates the link between the Brønsted/Lewis acid balance introduced by different elements (Al, Ga, In, Ti, Zr, Hf) inserted or finely dispersed in/onto the structure of extra-small silica nanospheres and the catalytic performances of the solids for two distinct biomass derivatives valorization reactions (i.e. conversion of glycerol to solketal and of ethyl levulinate to γ-valerolactone).The optimizations of the syntheses were particularly focusing on the insertion of the element inside the SiO2 matrix to maximize the number of acid sites. In-depth characterizations were conducted on the different substituted nanospheres to probe their morphological, structural, and textural features. A special attention was dedicated to the characterization of the surface acidity. These results were put into perspective with the catalytic performances of the materials. At the end of the investigations, we were able to explain the difference in terms of catalytic activity between the different studied solids and identify the optimal acid properties for the targeted reactions. The stability and recyclability of the best working solids were also assessed, an acute tuning of reaction conditions enabled to reach significatively high conversions, and their performances were tested in challenging conditions (i.e. close to crude feedstock).The knowledge unveiled through these investigations will give precious insight to design new silica-based catalysts with the appropriate acidity for a wide variety of acid-catalyzed reactions.

Jury Prof. Catherine MICHAUX (UNamur), PrésidenteProf. Yoann OLIVIER (UNamur), secrétaireProf. Piotr DE SILVA (Technical University of Denmark)Prof. Daniel ESCUDERO MASA (KULeuven)Prof. Benoît CHAMPAGNE (UNamur)Prof. Luc HENRARD (UNamur) Abstract Organic Light Emitting Diodes (OLEDs) are now a well-established technology in modern electronic devices, from flexible TV screens to lighting applications. Each time we use our smartphone, billions of tiny molecules are electrically stimulated to emit the colorful light reaching our eyes. The ability of these molecules to convert electricity into light is the core principle of an OLED, and understanding the mechanisms behind this process can help improve their performance.Recently, two new families of triangular-shaped organic molecular systems, known as Multi-Resonant (MR) and Inverted Singlet-Triplet (INVEST) compounds, have shown promising features for OLED applications.In my PhD research, I used computational chemistry to explore the quantum mechanical effects that define the peculiar features of these systems.The first part of my thesis focused on identifying the correct computational protocol to properly describe the energy and nature of the singlet and triplet excited states of the INVEST compounds, highlighting the importance of methods including double excitations.  With this information in our hands, we combined quantum chemistry and group theory to design new light-emitting INVEST compounds. Finally, we applied both static and dynamic approaches to describe the spin conversion processes in MR and INVEST systems, providing a comprehensive picture of their electronic and photophysical properties for next generation OLED applications.

Jury Prof. Xavier DE BOLLE (UNamur), présidentProf. Jean-Yves MATROULE (UNamur) secrétaireDr Karrera DJOKO (Durham University)Dr Soufian OUCHANE (Paris-Saclay University)Dr Rob VAN HOUDT (SCK-CEN) Abstract The copper tolerance of the free-living bacteria Caulobacter crescentus depends on its dimorphic cell cycle. The sessile stalked cell detoxifies and effluxes copper through the multicopper oxidase PcoA and the Cu transporter PcoB respectively, while the swarmer cell senses and swims away from Cu sources. The transcriptional landscape of both morphotypes upon copper excess further confirms this. Among the few genes upregulated in both stalked and swarmer cells under copper excess, the CCNA_00027-00028 operon encodes a TonB-dependent receptor (TbcT) and a 2-oxoglutarate/Fe2+-dependent oxygenase (OxcT), respectively. The deletion of these two genes specifically increases the sensitivity towards Cu in C. crescentus. Interestingly, using a bioinformatics approach, we observed that the tbcT and oxcT genes co-occur in at least 67 % of bacteria containing a tbcT gene, and 88 % of bacteria containing an oxcT gene. The TbcT-OxcT system is not involved in the transport of copper nor the detoxification of copper-induced oxidative stress. Previous studies in C. crescentus and for homologous proteins showed that TbcT seems to be involved in iron import via siderophores, even though C. crescentus does not appear to synthesize siderophores. The overexpression of the tbcT gene appears to enhance the import of iron. OxcT activity is important for copper tolerance, although its specific activity has not yet been deciphered. Based on our results, we demonstrated that proper iron import is crucial for complete Cu tolerance, with the intracellular iron preventing copper accumulation. Taken together, our results argue for a tight coupling between iron and copper homeostasis in the context of copper tolerance. 

Jury Prof. Nathalie BURNAY (UNamur), présidenteProf. Sabine HENRY (UNamur), secrétaireDr. Florence DE LONGUEVILLE (UNamur)Prof. Nathalie MONDAIN (Université d’Ottawa)Prof. Etienne PIGUET (Université de Neuchâtel)Prof. Sane TIDIANE (Université Assane Seck/Ziguinchor) Abstract Recent attention to environmental change has highlighted its impact on rural communities, particularly in Africa, where household-level adaptations play a crucial role in larger societal responses. Current research often overlooks these small-scale, everyday adaptations and how they evolve over time, limiting our understanding of rural communities' dynamic responses to environmental changes. This study focused on households living in rural West Africa, more specifically in the region of Saint-Louis in Senegal. To capture the complexity of the household adaptation journeys, the structured timeline mapping methodology was developed, which consists of completing timelines during interviews. Timelines were collected from 39 individuals in 17 households to explore how families perceive and adapt to environmental shifts. In addition, this research reflected on the added value and necessity of interviewing multiple household members to capture diverse lived experiences and ensure a comprehensive household-level perspective.Analysis of the data categorized the adaptation journeys into four typological groups reflecting different sensitivities and adaptive capacities: (1) diversified adjusters, (2) system maintainers, (3) environmental independence strivers, and (4) opportunity-driven adapters. All groups have differentiated responses to similar environmental changes, with differences in the temporality of the response, differences in the types of adaptations, and differences in the amount and diversity of adaptations. These differences result in resilience that evolves unevenly over time. Understanding these varied adaptation pathways lead to formulate policy recommendations aimed at improving adaptive capacity, resilience, and sustainable livelihoods.

Chers enseignants, Nous avons le plaisir de vous inviter à une expérience éducative unique à l’Observatoire Astronomique Antoine Thomas. Offrez à vos élèves l’opportunité de découvrir l’Observatoire Astronomique Antoine Thomas, un observatoire construit sur les lieux-mêmes où les pères jésuites avaient établi leur propre coupole d’observation, de formation et de recherche, au XIXe siècle. Situé dans le centre-ville de Namur, au cœur de l’université, notre observatoire est équipé d’instruments de pointe, pour l’observation nocturne, mais aussi diurne, avec l’un des plus grands télescopes solaires de Belgique. Une visite de l’observatoire permet de découvrir comment se pratique aujourd’hui l’astronomie et – si les conditions météorologiques le permettent – d’observations le soleil en toute sécurité. Planifiez votre visite dès aujourd’hui ! Pour organiser une visite scolaire, veuillez remplir le formulaire d’inscription disponible sur notre site web.  Infos pratiques :Visite guidée 1ère à 6ème secondaire 13h30 à 14h30 ou 15h00 à 16h00 Faculté de médecine • Place du Palais de Justice, Namur Gratuit • Sur inscription L'observatoire n'est pas accessible aux personnes à mobilité réduiteProchaines dates :10 décembre 202414 janvier 202511 février 2025 Inscription aux visites

Conférence de Chimie donnée par le Dr. Thomas Boltje de l'Université de Radboud de Nimègue.Bienvenue à tous.

Jury Prof. Gaëlle PONTAROTTI (Université de Namur), présidenteProf. Claire DIEDERICH (Université de Namur), secrétaireProf. Christel MOONS (Université de Gand)Prof. Karin HANNES (KULeuven)Prof. Franck MEIJBOOM (Universiteit Utrecht)Prof. Saskia ARNDT (Universiteir Utrecht)Dr Claudia HIRTENFELDER (Independent Researcher)Dr Trudy SHARP (Department of Regional NSW, Australia) Résumé Le rapport 2018 des Nations Unies World Urbanization Prospects prévoit que d’ici 2050, 68 % de la population humaine vivra en zone urbaine, ce qui causera une augmentation des interactions entre les humains et les animaux non humains. Jusqu’à présent, la recherche sur le bien-être des animaux s’est principalement concentrée sur les environnements contrôlés tels que les laboratoires, la production animale industrielle et les zoos. Cependant, dans les milieux urbains, la complexité des écosystèmes et les effets des interactions homme-animal doivent être pris en compte. L’argumentation de cette thèse est que la science du bien-être animal devrait être élargie pour inclure et répondre aux défis spécifiques des contextes urbains. En effet, la biopolitique urbaine actuelle privilégie principalement les intérêts humains et ignore souvent les perspectives et les besoins des animaux domestiques et commensaux.La thèse présente cinq publications, qui examinent le développement, la mise en oeuvre et la perception publique de la gestion gouvernementale qui influence le bien-être des animaux urbains. Deux questions de recherche sont élaborées sur la base des lacunes identifiées afin d’étudier les aspects éthiques, scientifiques et politiques du bien-être des animaux urbains en Belgique. D’une part, comment la politique gouvernementale et sa mise en oeuvre influencent-elles le bien-être des animaux urbain (domestiques et commensaux), avec une attention particulière pour les chats, chiens, pigeons, renards, souris et rats ? D’autre part, quelles stratégies peuvent améliorer la coexistence harmonieuse urbaine de ces animaux avec les humains du point de vue du bien-être animal ? Les réponses à ces questions seront fournies lors de la défense publique. Abstract The 2018 UN World Urbanization Prospects report predicts that by 2050, 68% of the human population will live in urban areas, which will lead to an increase in interactions between humans and non-human animals. Animal welfare research has hitherto mainly focused on controlled environments such as laboratories, animal industry and zoos. In urban environments, on the other hand, the complexity of ecosystems and the effects of human-animal interactions must be taken into account. The thesis in this dissertation is that animal welfare science should be further developed to tackle the specific challenges of urban contexts. In addition, current urban biopolitics gives priority to human interests and often ignores the perspectives and welfare needs of both domestic and commensal animals.The dissertation presents five publications, looking at the development, implementation and public perception of governmental policy and management that influences the welfare of urban animals. Two research questions are developed based on the identified research gaps in order to study the ethical, scientific and policy-related aspects of urban animal welfare in Belgium. On the one hand, how do governmental policy and its implementation influence the welfare of urban animals (domestic and commensal), with particular attention to cats, dogs, pigeons, foxes, mice and rats? On the other hand, what strategies can enhance the harmonious urban coexistence of these animals and humans from the point of view of animal welfare? Answers to these questions will be provided during the public defense.

JuryProf. DE BOLLE Xavier (UNamur), PresidentProf. VINCENT Stéphane (UNamur), SecretaryProf. BOLTJE Thomas (Radboud University)Prof. GUIANVARC’H Dominique (Paris-Saclay University)Prof. WOUTERS Johan (UNamur)AbstractMannose is a carbohydrate that we can naturally find in some bacterial cell envelope, more precisely in lipopolysaccharide core. To explore the metabolic route of this natural sugar: Metabolic Gylcoengineering (MGE) has been employed for studying biomolecules in living systems. We aim to chemically modify the cell surfaces to install unnatural monosaccharides that are metabolically transformed and incorporated by microorganisms. The metabolic incorporation into glycans pathway can be visualized by biorthogonal click reactions with fluorescent reporters that can bind to unnatural carbohydrates. In this project, the strategy is to synthesize several mannose derivatives to target the metabolic route of D-mannose and explore the glycosylation pathway in Gram-negative bacteria.On top of that, another application is to apply this clickable mannose as an interesting building block to synthesize nucleotide sugar for antibodies (Ab) functionalization. Indeed, antibody-drug conjugates (ADC) constitute a new emerging class of highly potent pharmaceutical drugs, especially in cancer therapy. The aim is to perform regioselective modification in antibody’s subunit containing glycan chains from GDP-mannose derivative. This latter must be synthesized and tested as unnatural mannose donors for glycosyltransferase that catalyzes the transfer of sugar moiety to mannose acceptor in specific site of the antibody. 

Au programme 13h30 | Exposés des lauréats13h30 | Luca Dorio (UMons)14h05 | Guillaume Gégo (UMons)14h40 | Manon Lenoir (UCLouvain)15h15 | Madeleine Martinussen (UCLouvain)16h00 | Camille Ponsard (UNamur)16h35 | Baptiste Vincent (UCLouvain)17h10 | Délibération du jury18h00 | Attribution des deux prix suivie d'une réception à l'espace Bauchau

Cet événement est ouvert à tous, jeunes et seniors, partenaires académiques et industriels, avec une priorité aux doctorants pour les conférences. Nous souhaitons encourager les directeurs de thèse à faire de cet événement un succès en invitant tous leurs étudiants à y participer. La langue de la réunion sera l'anglais.   Trois orateurs principaux sont prévus :Vincent Rodriguez (Université de Bordeaux, France) | Utilisation de la lumière polarisée linéairement pour sonder l'activité chiroptique non linéaire des molécules et des foldamères d'oligoamides aromatiquesProf. Tatjana N. Parac-Vogt (KU Leuven) | Enzymes artificielles basées sur des grappes d'oxydes métalliques : des espèces discrètes aux matériaux étendusChristophe Copéret (ETH Zürich, Suisse) | Contenu préliminaire « Moitié catalyse et moitié RMN ». Différents créneaux pour 10 short talks (15 mins de présentation + 5 mins de Q/A) ainsi que 10 flashs posters (2 mins) seront disponibles pour les doctorants. Les doctorants et les chercheurs post-doctorants auront également la possibilité de présenter leurs travaux lors de sessions de posters. Les meilleures présentations orales et affichées seront récompensées.La participation est gratuite mais l'inscription est obligatoire via ce formulaire... 

Two talks will be held:Renato OLARTE HERNANDEZ from UNamur will talk about: "Second Quantization in Quantum Chemistry".He will be followed by the talk of Prof. Marc de WERGIFOSSE (UCLouvain) entitled "Natural Response Orbitals and the RespA Procedure". 

Un drink sera organisé suite à la conférence.Cette conférence est proposée par "Kàp to UNIVERSEH", le projet sans kot de vulgarisation spatiale de l'Université de Namur, et Local Student Club d'UNIVERSEH.Quand : mercredi 26 février 2025 à 19hOù : Faculté des Sciences - Auditoire S01Gratuit Je m'inscris