Search results

Jury Prof. Marielle BOONEN (UNamur), presidentProf. Henri-François RENARD (UNamur), secretaryProf. Claire HIVROZ (PSL University)Prof. Michel GHISLAIN (UCLouvain)Prof. Pierre VAN DER BRUGGEN (UCLouvain)Prof. Ludger JOHANNES (PSL University)Prof. Pierre MORSOMME (UCLouvain) Summary Clathrin-independent endocytosis (CIE) mediates the cellular uptake of endogenous and exogenous cargoes, including bacterial toxins and viruses. Endophilin A3-mediated endocytosis is a specific CIE mechanism that differs from fast endophilin-mediated endocytosis (FEME), with ALCAM and L1CAM being the first confirmed Endophilin A3-specific cargoes. Here, we report ICAM1 as a new Endophilin A3-dependent endocytic cargo. ALCAM and ICAM1 are important components of immune synapses (IS), which are polarized structures formed between immune cells and target cells, such as cancer cells. These molecules transduce essential co-stimulatory signals to T cells to help their effective activation and proliferation. We find that both ALCAM and ICAM1 serve as cargoes for retromer-dependent retrograde transport to the trans-Golgi network (TGN) in cancer cells. Interestingly, disrupting Endophilin A3-mediated endocytosis or retromer-dependent retrograde transport machinery impairs activation of autologous cytotoxic CD8 T cells, possibly by affecting the polarized redistribution of immune synapse components at the plasma membrane. Altogether, our findings demonstrate that CIE and retrograde transport are key pathways in cancer cells that promote the activation of cytotoxic CD8 T cells.

Jury Prof. Yves CAUDANO (UNamur), chairmanProf. André FÜZFA (UNamur), secretaryProf. Dominique LAMBERT (UNamur)Dr. Jérémy REKIER (Observatoire royal de Belgique et UCLouvain)Prof. Dr. Félix FINSTER (Regensburg University) Summary Sounding the Universe with a relativistic solar sailboat or Einstein-Dirac fermionsThe Universe exerts a curiosity on man that is both undeniable and fundamental. To unravel the mysteries of the Cosmos, man is driven to develop two major investigative strategies: direct exploration by sending space probes, and indirect exploration by observing cosmic electromagnetic fields, gravitational waves or particles such as fermions.Following these two strategies, in this thesis we develop, in the first approach (consisting of sending a space probe), a relativistic kinematic and dynamical model of photonic sails (light sails) with arbitrary reflectivity and absorbance, moving in a non-rectilinear manner with the aim of exploring interstellar space. The problem is to determine the sail's trajectory in a Minkowski spacetime, a four-dimensional variety. From detailed calculations, we obtain the sail's universe line in the laser reference frame as a function of the sail's proper time.The second approach applies the Two-State Vector Formalism and weak measurements to a homogeneous, isotropic cosmological framework. By coupling Dirac spinners to classical gravity, we calculate weak values of the energy-impulse tensor, the Z component of spin and pure states. Extending the work of Finster and Hainzl on Einstein-Dirac cosmology, we show that the accelerated expansion of the Universe can be interpreted as a consequence of post-selection. We also demonstrate that weak measurements can amplify signals using simpler equipment, thanks to judicious selection of the initial and final state vectors. In addition, this procedure highlights certain geometric properties of the Cosmos' three-dimensional space, offering a new way of exploring the structure of the Universe.We also examine the mathematical structure on which the Dirac equation rests beyond the usual dimension and signature. This reveals a rich internal symmetry and gives rise to a particularly aesthetic diagrammatic representation. Abstract Probing the Universe with a Relativistic Light Sail or Einstein-Dirac FermionsHumanity's profound curiosity about the cosmos is both undeniable and fundamental. To demystify the Universe, humankind is compelled to develop both direct and indirect probing strategies: direct exploration through physical visits using probes, and indirect exploration by observing cosmic electromagnetic field, gravitational waves and particles such as fermions.Building on these two strategies, this thesis proposes two distinct approaches to probing the Universe. In the first approach, we present a relativistic kinematic and dynamic model of light sails with arbitrary reflectivity and absorptance, undergoing non-rectilinear motion as a method of interstellar exploration. The problem involves solving for the trajectory of the sail in a 4-dimensional Minkowski spacetime manifold. By detailed computation, we derive the worldline of the sail in the laser's frame in the sail's proper time.The second approach applies the Two-State Vector Formalism and weak measurements to a spatially homogeneous and isotropic cosmological framework. Coupling Dirac spinors with classical gravity, we compute weak values of the energy-momentum tensor, the Z-component of spin, and pure states. Extending the work of Finster and Hainzl on Einstein-Dirac cosmology, we demonstrate that the Universe's accelerated expansion can be interpreted as a consequence of post-selection. We also show that weak measurements can amplify signals with simpler equipment by carefully selecting initial and final state vectors. This process also reveals geometric properties of the spacelike three-manifold of the Cosmos, opening new way on probing the structure of the Universe.We explore also the mathematical framework underlying the Dirac equation beyond the standard dimension and signature. This enterprise reveals its symmetrically rich properties and aesthetic diagrammatic representation.

A drink will be organized following the lecture.This lecture is proposed by "Kàp to UNIVERSEH", the kot-free space popularization project of the University of Namur, and Local Student Club of UNIVERSEH.When: Wednesday, February 26, 2025 at 7pmWhere: Faculty of Sciences - Auditorium S01Free I want to register

Practical info Date: Wednesday, March 12, 2025Location: PA01, entrance will be via the Faculty of Science lobby6:45pm: Doors open7:15pm: Show startsPrice and ticket sales: €5 pre-sale / €7 on the daySales: At lunchtime throughout the week of March 3 in the college hall!Payment: We prefer cash, but also accept payment by QR code or bank transfer. Read more

The IPCC warns of the growing impact of global warming on water, with more frequent droughts and floods threatening global supplies. By 2050, 42% of river basins will be severely affected, and flood damage could quadruple in the event of 4°C warming. Although they bear little responsibility, the most vulnerable populations suffer the worst consequences. In Wallonia, recent climatic disasters and water pollution illustrate the stakes. To raise public awareness, an event is being organized in Charleroi with debates and screenings.Program17:00 | Introductory session Head of UNESCO Belgium Mr Aurélien Dumont, Secretariat of UNESCO's Intergovernmental Hydrological Programme, World Water Situation17:40 | Screening of the film "H2O, water, life and us: the Emergency"18:30 | Break18:45 | Lectures and debate Prof. Dr. Marnik Vanclooster (U.K.). Marnik Vanclooster (UCLouvain), "Situation en Wallonnie" Prof. Alfred Bernard (UCLouvain), "Normes et toxicologie" Debate Moderated by Prof. Karim ZouaouiBouin (UCLouvain). Karim ZouaouiBoudjeltia (ULB), with the participation of Aurélien Dumont, Marnik Vanclooster, Alfred Bernard.20:30 | Cocktail dinnerGRATULAR : Registration required: f.amer@wbi.beThe members of the "exact and natural sciences" Sub-CommissionBernard Feltz (UCLouvain, Chairman), Bertrand Hespel (UNamur), Marie-Geneviève Pinsart (ULB, CIGB), René Rezsohazy (UCLouvain), Frédéric Rychter (Secrétaire général), Olivier Sartenaer (UNamur), Didier Serteyn (ULiège), Anne Staquet (UMons), Marnik Vanclooster (UCLouvain), Karim Zouaoui Boudjeltia (ULB)

High-Sensitivity Birefringence Mapping Using Near-Circularly Polarized Light I will describe several techniques for mapping a two-dimensional birefringence distribution, which can be classified according to the optical schemes and principles of work:Illumination geometry (transmitted light/reflected light)Image acquisition (sequential acquisition/simultaneous acquisition)Polarization control (electrically controlled variable retardance/mechanical rotation).This classification facilitates a comparative analysis of the capabilities and limitations in these methods for birefringence characterization. Polychromatic polarizing microscopy (PPM) provides unique capabilities to alternative methods. It leverages vector interference to generate vivid, full-spectrum colors at extremely low retardances, down to < 10 nm. PPM is a significant departure from conventional polarizing microscopes that rely on Newton interference, which requires retardances above 400 nm for color formation. Furthermore, PPM's color output directly reflects the orientation of the birefringent material, a feature absent in conventional microscopy where color is solely determined by retardance.Joint seminar of ILEE & NISM!The seminar is open to external people too, no need to register. More info

Abstract Radiotherapy is a cornerstone of cancer treatment and is currently administered to approximately half of all cancer patients. However, the cytotoxic effects of ionizing radiation on normal tissues represent a major limitation, as they restrict the dose that can be safely delivered to patients and, consequently, reduce the likelihood of effective tumor control. In this context, delivering radiation at ultra-high dose rates (UHDR, > 40 Gy/s) is gaining increasing attention due to its potential to spare healthy tissues surrounding the tumor and to prevent radiation-induced side effects, as compared to conventional dose rates (CONV, on the order of Gy/min).The mechanism underlying this protective effect-termed the FLASH effect-remains elusive, driving intensive research to elucidate the biological processes triggered by this type of irradiation.In vitro models offer a valuable tool to support this research, allowing for the efficient screening of various beam parameters and biological responses in a time- and cost-effective manner. In this study, multicellular tumor spheroids and normal cells were exposed to proton irradiation at UHDR to evaluate its efficacy in controlling tumor growth and its cytotoxic impact on healthy tissues, respectively.We report that UHDR and CONV irradiation induced a comparable growth delay in 3D tumor spheroids, suggesting similar efficacy in tumor control. In normal cells, both dose rates induced similar levels of senescence; however, UHDR irradiation led to lower apoptosis induction at clinically relevant doses and early time points post-irradiation.Taken together, these findings further highlight the potential of UHDR irradiation to modulate the response of normal tissues while maintaining comparable tumor control.JuryProf. Thomas BALLIGAND (UNamur), PresidentProf. Stéphane LUCAS (UNamur), SecretaryProf. Carine MICHIELS (UNamur)Dr Sébastien PENNINCKX (Hôpital Universitaire de Bruxelles)Prof. Cristian FERNANDEZ (University of Bern)Dr Rudi LABARBE (IBA)

The conference is co-organized by the University of Namur, Belgium and Wuhan University of Technology, China and supported by Foshan Xianhu Laboratory and other organisms.More info on the GCMC2025 website...

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)

Welcome to the 1ʳᵉ MG-ERC conference This conference, linked to the research themes of the Chemistry Department, aims to bring together around 100 researchers working in the fields of heteroatom chemistry, coordination chemistry, catalysis, and inorganic chemistry. It represents a real novelty in Belgium in terms of the areas covered, and will enable participants to discover new concepts, ideas and trends in these recent areas of research in chemistry. Here is the list of speakers, who are world experts in their fieldsDr. Daniël Broere (Utrecht University, Netherlands)Prof. Agnieszka Nowak-Król (Universität Würzburg, Germany)Dr. Antoine Simonneau (Université Paul-Sabatier, Toulouse, France)Prof. Dr. Sebastian Riedel (Freie Universität, Berlin, Germany)Dr. Arnaud Voituriez (Université Paris-Saclay, France)Prof. Dr. Alessandro Bismuto (Universität Bonn, Germany)Dr. Christian Hering-Junghans (Leibniz-Institut für Katalyse, Germany)Prof. Connie Lu (Universität Bonn, Germany)Prof. Simon Aldridge (University of Oxford, UK)Dr. Ghenwa Bouhadir (Université Paul-Sabatier, Toulouse, France)Prof. Dr. Viktoria Däschlein (Universität Bonn, Germany)Prof. Viktoria Däschlein-Gessner (Ruhr-University of Bochum, Germany)Dr. Jennifer A. Garden (University of Edinburgh, UK)Prof. Muriel Hissler (Université de Rennes, France)Prof. Jean-François Paquin (Université de Laval, Canada) More information and registration