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AbstractIn CO2-rich atmospheres such as that of Venus, the study of water vapor requires the use of H2O collision parameters for CO2. However, due to a lack of data, models still use collision parameters for air to estimate the abundance of water vapor in this type of atmosphere. In this thesis, new experimental laboratory measurements of the collision parameters of H2O, HDO, and D2O by CO2 were carried out. These were then used as the basis for dedicated theoretical calculations. Their impact was evaluated using radiative transfer simulations applied to the atmosphere of Venus, under conditions close to those of future observations by the European EnVision mission. The results clearly show that using collision parameters for air instead of CO2 can lead to an overestimation of nearly 40% of the abundance of water vapor in the mesosphere and to inversion difficulties in the troposphere. This work thus provides essential elements for improving the spectral analysis of CO2-rich atmospheres.JuryDr. Ha TRAN (Sorbonne University), ChairProf. Muriel LEPÈRE (University of Namur), SecretaryDr. Emmanuel MARCQ (University of Versailles)Dr. David JACQUEMART (Sorbonne University)Dr. Laurence RÉGALIA (University of Reims)Dr. Séverine ROBERT (Royal Institute for Space Aeronomy, Belgium)

AbstractNosocomial infections are a major public health problem, exacerbated by the global spread of bacterial resistance to antibiotics. Faced with this challenge, it is crucial to explore alternatives or complementary strategies to conventional treatments. Among these, the use of copper is attracting renewed interest. This metal has natural antibacterial properties that have been recognized since ancient times. It acts through multiple mechanisms such as membrane alteration, the generation of reactive oxygen species, and the denaturation of proteins and nucleic acids, leading to rapid cell death. These characteristics make it an effective biocidal agent in many contexts, particularly in hospitals.However, the selective pressure exerted by the increased presence of copper in the environment has led to the emergence of specific resistance systems in certain bacteria. These systems allow strict control of copper homeostasis by limiting its intracellular accumulation through efflux, sequestration, or oxidation mechanisms. In Caulobacter crescentus, an environmental bacterial model, copper resistance is based in particular on the Pco system. This system is composed of the PcoB protein, located in the outer membrane. Although its structure has been partially described in E. coli, its precise function remains unclear. Preliminary observations suggest that it may be involved in the export of copper from the periplasm to the outside of the cell, thus acting as a release pathway.To explore the role of PcoB in bacterial copper resistance, this study focused on the structural and functional characterization of the protein. After extraction and purification, PcoB was incorporated into artificial liposomes to develop an in vitro transport assay to assess its ability to release copper across a lipid bilayer. At the same time, a truncated mutant lacking the disordered N-terminal region was produced and subjected to the same analyses. The comparison between the complete and truncated forms aims to determine the involvement of this flexible region in the transport mechanism and stability of the protein. These approaches have laid the initial experimental foundations for studying the transport mechanism of PcoB and constitute a first step towards a detailed understanding of how the Pco system works. They also open up prospects for the development of new antibacterial strategies targeting copper management systems in bacteria.JuryProf. Johan WOUTERS (UNamur), ChairDr. Catherine MICHAUX (UNamur), SecretaryProf. Jean-Yves MATROULE (UNamur)Dr. Guillaume ROUSSEL (UCLouvain)Prof. Francesca CECCHET (UNamur)Prof. Hennie VALKENIER (ULB)

In line with its predecessors, ICEL 2026 will provide an excellent opportunity for the intellectual and social exchanges that keep our community closely connected. It will bring together participants from all over the world involved in the research, development, and manufacturing of emissive materials. A wide array of subjects will be explored, offering a comprehensive perspective on contemporary advances in these fields. We extend a warm invitation for the dissemination of recent breakthroughs in related topics, with a particular emphasis on fostering the active participation of young and motivated researchers.We especially expect to cover the following topics:Thermally Activated Delayed Fluorescence emittersRadical emittersOrganometallic complexesPerovskitesLasingCircularly polarized luminescenceLight emission from exciplexesGreen- and biophotonicsComputational modeling of light-emitting materialsAll practical information (registration, abstract submission, and accommodation) is available on the ICEL2026 website. Access the ICEL2026 website

Our keynote speakers for 2026 are Professor Roosmarijn Vandenbroucke (Ghent University) and Professor Nelly Litvak (Eindhoven University of Technology). More information on the "Women in Science" website

Every two years, the International Symposium on Marek's Disease and Avian Herpesviruses (MDAH) brings together researchers from around the world to exchange the latest insights on poultry viral diseases - covering their biology, evolution, control strategies, and epidemiology. Attendees include PhD students, postdocs and researchers representing academia, government, and commercial organizations from North and South America, Europe, Asia, the Middle East, Australia, and Africa. More information on the MDAH2026 website

Deadlines Opening of abstract submissions and registrations: September 15, 2025Deadline to submit indicative title and summary: November 30, 2025Deadline for final abstract submissions: May 1, 2026Early bird registration deadline: March 1, 2026 More information on the website

Abstract This work demonstrates that polymer-coated gold nanoparticles can function not only as radiosensitizers but also as agents for macrophage reprogramming. Specifically, we show that these nanoparticles can repolarize tumor-associated macrophages from the immunosuppressive M2 phenotype to the pro-inflammatory M1 phenotype-a process further enhanced by clinically relevant doses of X-ray radiation. Among the four nanoparticle formulations tested, 50 nm PVP-coated gold nanoparticles were particularly effective in promoting macrophage repolarization and reducing pancreatic cancer cell viability in co-culture, both with and without radiation. These findings highlight a promising strategy to enhance the efficacy of cancer radiotherapy. Jury Prof. Julien COLAUX (UNamur), ChairmanProf. Anne-Catherine HEUSKIN (UNamur), SecretaryProf. Carine MICHIELS (UNamur)Prof. Henri-François RENARD (UNamur)Prof. Michel MOUTSCHEN (ULiège)Dr Dimitri STANICKI (UMons)Prof. Devika CHITHRANI (University of Victoria)

SummaryIn 2025, machine learning continues to revolutionize various scientific fields, with major implications in physics, particularly photonics. The integration of advanced machine learning algorithms has enabled significant advances in the design and control of photonic systems, improving their efficiency and performance. These advances are essential for the development of communication, imaging and quantum computing technologies. However, physics research presents many challenges that go beyond simple performance measurements: identifying patterns and building analytical models is often just as crucial.In this thesis, we apply computational intelligence tools, in particular heuristic optimization and neural networks, to develop data-driven approaches to solving various tasks in physics. Although data-centric, our approach remains rooted in physics, always seeking to understand the physical phenomena underlying the algorithms. The results of this thesis cover a wide range of applications, from the design of complex metasurfaces and diffraction gratings to the analysis and interpretation of spectral data. We have also successfully developed an optimizer capable of learning and adapting to the problems encountered, particularly in physics. This key tool in our arsenal outperforms state-of-the-art methods in our applications. In particular, it has enabled the design of a coronagraphic phase plate for exoplanet imaging, with a performance 25% better than the best previous solutions.We have also designed a compact, all-dielectric beam deflection device, operating efficiently for all polarizations, reaching a maximum efficiency of 90%. Starting from a purely data-driven design, we were able to extract and validate an analytical model based on the behavior of an echelle lattice, providing a physical understanding of its operation. In addition to simulation-based tasks, we also processed experimental data, developing an animal origin classifier for scrolls, capable of distinguishing three animal species with 90% accuracy. This tool offers a non-invasive method for conservators and historians wishing to analyze fragile historical materials.Jury members Prof. Michaël LOBET (UNamur), PresidentProf. Alexandre MAYER (UNamur), SecretaryDr. Charlotte BEAUTHIER (CENAREO)Prof. Benoît FRENAY (UNamur)Prof. Olivier DEPARIS (UNamur)Prof. Denis LANGEVIN (Université de Clermont Auvergne)Prof. Hai Son NGUYEN (Ecole Centrale de Lyon)

Essay topic Essays on the Empirical Analysis of Crypto-Assets: Market Efficiency, Peg Failures, and Financial Flights Composition of the Jury Promoter: Prof. Jean-Yves Gnabo (UNamur)Other jury members: Prof. Sophie Béreau (UNamur)Prof. Kris Boudt (UGent)Prof. Sarah Bouraga (EM Normandie)Prof. Jérôme Lahaye (Fordham University)Jury president: Prof. Corentin Burnay (UNamur)

Abstract Primarily described as an alarmone, secondary messenger (p)ppGpp, when accumulated, binds to many targets involved in DNA replication, translation, and transcription. In the asymmetrically-dividing a-proteobacterium Caulobacter crescentus, (p)ppGpp has been shown to strongly impact cell cycle progression and differentiation, promoting the non-replicating G1/swarmer phase. Mutations in the major subunits of transcriptional complex, b or b' subunits, were able to display the (p)ppGpp-related phenotypes even in the absence of the alarmone. We identified that the transcriptional holo-enzyme, RNA polymerase (RNAP) is a primary target of (p)ppGpp in C. crescentus. Furthermore, mutations that inactivate (p)ppGpp binding to RNAP annihilated the (p)ppGpp-related phenotypes and phenocopied a (p)ppGpp0 strain. Our RNAseq analysis further elucidated the changes in the transcriptional landscape of C. crescentus cells displaying different (p)ppGpp levels and expressing RNAP mutants. Since the DNA replication initiation protein DnaA is required to exit the G1 phase, we observed that it was significantly less abundant in cells accumulating (p)ppGpp. We further explored its proteolysis under the influence of (p)ppGpp. Our work suggests that (p)ppGpp regulates cell cycle and differentiation in C. crescentus by reprogramming transcription and triggering proteolytic degradation of key cell cycle regulators by yet unknown mechanisms. In Part II, we identified two σ factors belonging to the ECF family that might be involved in this (p)ppGpp-accompanied phenotypes. In Part III, we propose an overlapping role of the ω subunit, RpoZ, and the heat shock subunit, RpoH, in carbon metabolism.JuryProf. Gipsi LIMA MENDEZ (UNamur), PresidentProf Régis HALLEZ (UNamur), SecretaryDr Emanuele BIONDI (CNRS-Université Paris-Saclay)Prof. Justine COLLIER (University of Lausanne)Dr Marie DELABY (Université de Montréal)

Abstract Estrogens originating from human and animal excretion, as well as from anthropogenic sources such as cosmetics, plastics, pesticides, detergents, and pharmaceuticals, are among the most concerning endocrine-disrupting compounds in aquatic environments due to their potent estrogenic activity. While their effects on fish reproduction are well documented, their impact on development, particularly metamorphosis, remains poorly studied. This hormonal transition, mainly controlled by the thyroid axis, is essential for the shift from the larval to the juvenile stage in teleosts.The effects of two contraceptive estrogens on zebrafish (Danio rerio) metamorphosis were evaluated: 17α-ethinylestradiol (EE2), a synthetic reference estrogen, and estetrol (E4), a natural estrogen recently introduced in a new combined oral contraceptive formulation. Continuous exposure from fertilization to the end of metamorphosis allowed the assessment of morphological changes, disruptions of the thyroid axis, and modifications of additional molecular pathways potentially involved in metamorphic regulation.EE2 induced significant delays and disturbances in metamorphosis, affecting both internal and external morphological traits, confirming its role as an endocrine disruptor of concern. In contrast, E4 did not cause any detectable morphological alterations even at concentrations far exceeding those expected in the environment, indicating a limited ecotoxicological risk. Molecular analyses showed that EE2 strongly affected thyroid signaling and energy metabolism during metamorphosis, whereas E4 induced only minor transcriptional and proteomic changes.This study provides the first evidence that EE2 can disrupt zebrafish metamorphosis and highlights the importance of including this developmental stage in ecotoxicological assessments. The results also suggest a larger environmental safety margin for E4, although further research is needed to clarify the mechanisms linking estrogen exposure to metamorphic regulation.JuryProf. Frederik DE LAENDER (UNamur), PresidentProf. Patrick KESTEMONT (UNamur), SecretaryDr. Sébastien BAEKELANDT (UNamur)Dr. Valérie CORNET (UNamur)Prof. Jean-Baptiste FINI (Muséum National d'Histoire Naturelle, Paris)Dr. Marc MULLER (ULiège)Prof. Veerle DARRAS (KULeuven)

SummaryAt a time when a stream of research was striving to reformulate quantum mechanics by abolishing operators and substituting functions, Wigner and Szilard proposed in 1932 a quasi-probability distribution defined on phase space thanks to wave functions. They did not explain its genesis.The first part of our thesis proposes a genesis of this quasi-distribution, based on the natural conditions it must fulfill. It briefly examines a pathology it suffers from: exhibiting negative values in certain subdomains of the phase space (hence the "quasi"), a pathology that does no harm to the calculation of mean values. She then shows how, if we take spin into account, with wave functions giving way to spinners, we are led, thanks to the calculation of mean values of observables, to a generalization of this quasi-distribution in the form of a Hermitian matrix. This approach is extended to the Wigner cross transform, i.e. to weak values.An important theorem, which has been the subject of a publication, is proved in the second part of our thesis. Using harmonic analysis, this result expresses weak values in terms of an integral over a Lie group acting on the Hilbert space under consideration. We give two particular examples: SU(2) and SO(3). The case of a quotient group is briefly discussed.In a third section, we recall the well-known link between Clifford algebras and two important equations of quantum physics: the Klein-Gordon and Dirac equations, and its generalization to Riemannian spacetimes.Finally, in a fourth section we introduce spin groups, and use the spin group Spin(3,2) in the context of the Wigner cross transform discussed in the first section.JuryProf. André FÜZFA (UNamur), PresidentProf. Yves CAUDANO (UNamur), SecretaryDr. Thomas DURT (Institut Fresnel and Ecole Centrale Marseille, Marseille, France)Prof. Romain MURENZI (Worcester Polytecnic Institute)Prof. Dominique LAMBERT (UNamur)Prof. Bertrand HESPEL (UNamur)Prof. André HARDY (UNamur)