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PSL Chemical Biology Symposia: The Increasing Impact of Chemistry in Life Sciences
No full textInternational audienceThis symposium is the 6th Paris Sciences & Lettres (PSL) Chemical Biology meeting (2015, 2016, 2019, 2023, 2024, 2025) being held at Institut Curie. This initiative originally started in 2013 at Institut de Chimie des Substances Naturelles (ICSN) in Gif‐sur‐Yvette and was mostly focused on organic synthesis. It was then exported at Institut Curie to cover a larger scope, before becoming the official French Chemical Biology meeting. This year, around 200 participants had the opportunity to meet world leaders in chemistry and biology who described their latest innovations and future trends covering topics as diverse as prebiotic chemistry, activity‐based protein profiling, high‐resolution cell imaging, nanotechnologies, bio‐orthogonal chemistry, metal ion signaling, ferroptosis, and biocatalysis
Directed searches for gravitational waves from ultralight vector boson clouds around merger remnant and galactic black holes during the first part of the fourth LIGO-Virgo-KAGRA observing run
No full textInternational audienceWe present the first directed searches for long-transient and continuous gravitational waves from ultralight vector boson clouds around known black holes (BHs). We use LIGO data from the first part of the fourth LIGO-Virgo-KAGRA observing run. The searches target two distinct types of BHs and use two new semicoherent methods: hidden Markov model (HMM) tracking for the remnant BHs of the mergers GW230814_230901 and GW231123_135430 (referred to as GW230814 and GW231123 in this study), and a dedicated method using the Band Sampled Data (BSD) framework for the galactic BH in the Cygnus X-1 binary system. Without finding evidence of a signal from vector bosons in the data, we estimate the mass range that can be constrained. For the HMM searches targeting the remnants from GW231123 and GW230814, we disfavor vector boson masses in the ranges and eV, respectively, at 30% confidence, assuming a 1% false alarm probability. Although these searches are only marginally sensitive to signals from merger remnants at relatively large distances, future observations are expected to yield more stringent constraints with high confidence. For the BSD search targeting the BH in Cygnus X-1, we exclude vector boson masses in the range eV at 95% confidence, assuming an initial BH spin larger than 0.5
Actualités de 2024 sur les troubles neurologiques du sommeil
No full textInternational audienceAt the annual French Sleep Congress, Laure Peter-Derex presented a review of impactful 2024 studies on neurological sleep disorders, focusing on the role of REM sleep behavior disorder (RBD) as an early marker of neurodegenerative diseases, the development of new RBD severity scales, and emerging biomarkers (e.g., language alterations) to predict progression toward Parkinson’s disease or dementia. She also emphasized that RBD can sometimes be linked to treatable autoimmune encephalitis, underscoring the importance of thorough etiological assessments. Finally, potential novel therapies such as acetyl-DL-leucine show preliminary promise for RBD prodromes, highlighting the need for clinical trials to assess their long-term efficacy and possible neuroprotective benefits.Au Congrès français du Sommeil, Laure Peter-Derex a présenté une revue des études marquantes de 2024 sur les troubles neurologiques du sommeil. Elle a notamment mis l’accent sur le rôle du trouble comportemental en sommeil paradoxal (TCSP) en tant que marqueur précoce de maladies neurodégénératives, sur l’élaboration de nouvelles échelles de sévérité spécifiques au TCSP ainsi que sur l’apparition de nouveaux biomarqueurs (par exemple, des altérations du langage) permettant de prédire la progression vers la maladie de Parkinson ou la démence. Elle a également souligné que le TCSP peut parfois être associé à des encéphalites auto-immunes potentiellement curables, soulignant ainsi l’importance d’une évaluation étiologique approfondie. Enfin, de nouvelles approches thérapeutiques, telles que l’acétyl-DL-leucine, semblent prometteuses dans le traitement des prodromes du TCSP, d’où la nécessité de mener des essais cliniques afin d’évaluer leur efficacité à long terme et leurs éventuels effets neuroprotecteurs
Design principles of deep translationally symmetric neural quantum states for frustrated magnets
No full textInternational audienceDeep neural-network quantum states have emerged as a leading method for studying the ground states of quantum magnets. Successful architectures exploit translational symmetry, but the root of their effectiveness and differences between architectures remain unclear. Here, we apply the ConvNext architecture, designed to incorporate elements of transformers into convolutional networks, to quantum many-body ground states. We find that it is remarkably similar to the factored vision transformer, which has been employed successfully for several frustrated spin systems, allowing us to relate this architecture to more conventional convolutional networks. Through a series of numerical experiments, we design the ConvNext to achieve greatest performance at lowest computational cost, and then apply this network to the Shastry-Sutherland and J 1 − J 2 models, obtaining variational energies comparable to the state of the art, providing a blueprint for network design choices of translationally symmetric architectures to tackle challenging ground-state problems in frustrated magnetism
Piéger les atomes
No full textInternational audienceC’est dans les années 1920 que l’hypothèse selon laquelle toute particule de matière est également une onde est vérifiée. Cette « dualité onde-corpuscule » est un des fondements de la physique quantique, et un de ses éléments les plus paradoxaux. Pour observer ces propriétés ondulatoires avec des atomes ou des molécules, il faut que leur mouvement soit très lent, et donc qu’ils soient très froids.C’est à cela que se consacre Jean Dalibard : refroidir des gaz d’atomes au plus près du zéro absolu, vers –270°C. Pour cela, il utilise des lasers, qui viennent s’opposer au mouvement des particules pour les ralentir. Cette prouesse expérimentale a conduit à des avancées majeures en physique fondamentale, et peut fournir une voie d’approche vers un futur ordinateur quantique.De manière très pédagogique, en inscrivant ses recherches dans le fil de l’histoire des sciences, Jean Dalibard nous dévoile certaines des propriétés les plus surprenantes de l’infiniment petit
Bloch oscillations of a soliton in a one-dimensional quantum fluid
No full textInternational audienceThe motion of a quantum system under an external force often challenges classical intuition. A notable example is the dynamics of a single particle in a periodic potential, which undergoes Bloch oscillations under the action of a constant force. Similar oscillations can also occur in one-dimensional quantum fluids without a lattice. The generalization of Bloch oscillations to a weakly bounded ensemble of interacting particles has so far been limited to the experimental study of the two-particle case, where the observed period is halved compared to the single-particle case. In this work, we observe the oscillations of the position of a mesoscopic solitonic wave packet—consisting of approximately 1,000 atoms—in a one-dimensional Bose gas subjected to a constant uniform force and in the absence of a lattice potential. The oscillation period scales inversely with the number of atoms, revealing its collective nature. We demonstrate the role of the phase coherence of the quantum bath in which the wave packet moves and investigate the underlying topology of the associated superfluid currents. Our measurements highlight the periodicity of the dispersion relation of collective excitations in one-dimensional quantum systems
Les terroirs syriens en recompositionGéographie politique de la Syrie au regard du temps long
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Substitution Pattern of the Secondary Rim of ICyD Ligand Influences Stereoselectivity
No full textInternational audienceThe synthesis and evaluation of N‐heterocyclic carbene (NHC)‐capped cyclodextrins with various protecting groups were carried out. The corresponding gold complexes catalyze the stereoselective cycloisomerization of enynes. Permethylation of the cyclodextrin's hydroxyl groups improves yield and selectivity compared to its benzylated counterpart. Notably, alternating methyl and benzyl groups on the secondary rim of the cyclodextrin further enhances asymmetry, achieving even higher enantioselectivities. To synthesize this compound, we optimized the selective deprotection of all benzyl groups at the 2‐position of the sugar residues in the cyclodextrin