@article{21037, abstract = {The oxygen reduction reaction (ORR) remains a critical bottleneck in fuel cells and metal-air batteries due to the lack of highly efficient electrocatalysts. Here, we report a simple strategy for synthesizing a palladium-based heterostructured electrocatalyst supported on a carbon nitride matrix (PdH-Pd@CN), which exhibits remarkable ORR activity with a half-wave potential of 0.91 V and excellent durability in 0.1 M KOH. Within the heterostructure, hydrogen intercalation expands the Pd lattice, while interstitial hydrogen doping facilitates charge transfer from Pd to H owing to their electronegativity difference. These synergistic effects modulate the electronic structure, thereby enhancing both activity and stability. When employed in Zn-air batteries, PdH-Pd@CN delivers a maximum power density of 176 mW cm− (Liu et al., 2025) and capacity of 805 mAh g− (Sun et al., 2021) Zn. These findings demonstrate the strong potential of PdH-Pd@CN as an efficient ORR electrocatalyst for next-generation metal-air batteries and related energy technologies.}, author = {Shi, Changwei and Horta, Sharona and Ibáñez, Maria and Kallio, Tanja and Martínez-Alanis, Paulina R. and Wang, Xiang and Cabot, Andreu}, issn = {0009-2509}, journal = {Chemical Engineering Science}, publisher = {Elsevier}, title = {{Hydrogen induced palladium-based heterojunction electrocatalysts to enhance the oxygen reduction reaction performance}}, doi = {10.1016/j.ces.2026.123348}, volume = {324}, year = {2026}, } @article{21038, abstract = {Little Red Dots (LRDs) are compact sources at z > 5 discovered through James Webb Space Telescope spectroscopy. Their spectra exhibit broad Balmer emission lines (>~1000 km s^−1), alongside absorption features and a pronounced Balmer break – evidence for a dense, neutral hydrogen medium, in which the n = 2 state is significantly populated. When interpreted as arising from active galactic nucleus broad-line regions, inferred black hole masses from local scaling relations exceed expectations given their stellar masses, challenging models of early black hole–galaxy co-evolution. However, radiative transfer effects in dense media may also impact the formation of hydrogen emission lines. We model three scattering processes shaping hydrogen line profiles: resonance scattering by hydrogen in the n = 2 state, Raman scattering of ultraviolet (UV) radiation by ground-state hydrogen, and Thomson scattering by free electrons. Using 3D Monte Carlo radiative transfer simulations, we examine their imprint on line shapes and ratios. Resonance scattering produces strong deviations from Case B flux ratios, clear differences between Hα and Hβ, and encodes gas kinematics in line profiles but cannot broaden Hβ due to conversion to Paα. While Raman scattering can yield broad wings, scattering of the UV continuum is disfavoured given the absence of strong full width at half-maximum variations across transitions. Raman scattering of higher Lyman-series emission can produce Hα/Hβ wing width ratios of >~1.28, agreeing with observations. Thomson scattering can reproduce the observed >~ 1000 km s^−1 wings under plausible conditions – e.g. Te ∼ 10^4 K and Ne ∼ 10^24 cm^−2 – and lead to black hole mass overestimates by factors 10. Our results provide a framework for interpreting hydrogen lines in LRDs and similar systems.}, author = {Chang, Seok Jun and Gronke, Max and Matthee, Jorryt J and Mason, Charlotte}, issn = {1365-2966}, journal = {Monthly Notices of the Royal Astronomical Society}, number = {4}, publisher = {Oxford University Press}, title = {{Impact of resonance, Raman, and Thomson scattering on hydrogen line formation in Little Red Dots}}, doi = {10.1093/mnras/staf2131}, volume = {545}, year = {2026}, } @article{21039, abstract = {Cellular plasticity, the ability of a differentiated cell to adopt another phenotypic identity, is restricted under basal conditions, but can be elicited upon damage. However, the molecular mechanism enabling such plasticity remains largely unexplored. Here, we report damage-induced cellular plasticity of secretory enteroendocrine cells (EEs) in the adult Drosophila midgut. Ionizing radiation induces EE fate conversion and activates stress-responsive programs in EE lineages, accompanied by the induction of the stress-inducible transcription factor Xrp1 and the cytokine gene upd3. Xrp1 and upd3 are both necessary for radiation-induced EE plasticity. Under basal conditions, EE-specific Xrp1 overexpression triggers ectopic expression of progenitor-specific genes, which is necessary for Xrp1 to drive EE plasticity. Our work identifies Xrp1 as a crucial regulator that coordinates damage-induced signaling and transcriptional reprogramming, enabling the reactivation of cellular plasticity in differentiated cells.}, author = {Qian, Qingyin and Nagai, Hiroki and Sanaki, Yuya and Hayashi, Makoto and Kimura, Kenichi and Nakajima, Yu Ichiro and Niwa, Ryusuke}, issn = {1477-9129}, journal = {Development}, number = {2}, publisher = {The Company of Biologists}, title = {{Xrp1 drives damage-induced cellular plasticity of enteroendocrine cells in the adult Drosophila midgut}}, doi = {10.1242/dev.205225}, volume = {153}, year = {2026}, } @article{21040, abstract = {Formation during the first cycles of Li-rich layered oxide (LRLO) cathode materials consolidates the interphase and leads to structural changes that are decisive for long-term cyclability. However, the nature and effect of the changes are material-dependent and unknown for the important class of Co-free, Ni-poor LRLOs. Here, we analyze the processes during the tailored formation procedure of a typical class member, Li1.28Ni0.15Mn0.57O2, and demonstrate that it remarkably changes lattice composition and structure as a prerequisite for stable cycling. We combine electrochemistry, operando mass spectrometry, X-ray diffraction, and X-ray absorption spectroscopy with density functional theory simulations. Activation most prominently compresses the layer spacing along the c-axis and increases reversible structural breathing. The large capacity of ∼250 mAh g–1 originates from the Ni2+/Ni4+ and O2–/O– redox couples. Electron exchange during O-redox is smeared over the entire anionic sublattice rather than localized on specific oxygen atomic sites. This redox mechanism is reversible without detrimental oxygen evolution, avoiding continued degradation common in conventional LRLOs. Sequential Ni- and O-redox during activation irreversibly distorts the coordination of the redox-inactive Mn4+ centers. This structural evolution of the MnO6 octahedra appears to enable the superior electrochemical performance of this LRLO phase. These findings define an activation pathway for the important class of Co-free, Ni-poor LRLOs, offering potential guidance for the rational design of high-performance, more sustainable cathode materials.}, author = {Busato, Matteo and Tuccillo, Mariarosaria and Celeste, Arcangelo and Tofoni, Alessandro and Silvestri, Laura and D’Angelo, Paola and Freunberger, Stefan Alexander and Brutti, Sergio}, issn = {2574-0962}, journal = {ACS Applied Energy Materials}, number = {1}, pages = {686--697}, publisher = {American Chemical Society}, title = {{Structural rearrangements of a Cobalt-free Lithium-rich layered oxide cathode during formation}}, doi = {10.1021/acsaem.5c03511}, volume = {9}, year = {2026}, } @article{21041, abstract = {It is common for programmers to assemble their programs from a combination of trusted and untrusted components. In this context, a trusted program component is said to be robustly safe if it behaves safely when linked against arbitrary untrusted code. Prior work has shown how various encapsulation mechanisms (in both high- and low-level languages) can be used to protect code so that it is robustly safe, but none of the existing work has explored how robust safety can be achieved in a patently unsafe language like C. In this paper, we show how to bring robust safety to a simple yet representative C-like language we call Rec. Although Rec (like C) is inherently ”dangerous” and thus not robustly safe, we can ”save” Rec programs via compilation to Cap, a CHERI-like capability machine. To formalize the benefits of such a hardening compiler, we develop Reckon, a separation logic for verifying robust safety of Rec programs. Reckon is not sound under Rec’s unsafe, C-like semantics, but it is sound when Rec programs are hardened via compilation and linked against untrusted code running on Cap. As a crucial step in proving soundness of Reckon, we introduce a novel technique of semantic back-translation, which we formalize by building on the DimSum framework for multi-language semantics. All our results are mechanized in the Rocq prover.}, author = {Mück, Niklas and Georges, Aïna Linn and Dreyer, Derek and Garg, Deepak and Sammler, Michael Joachim}, issn = {2475-1421}, journal = {Proceedings of the ACM on Programming Languages}, pages = {1153--1182}, publisher = {Association for Computing Machinery}, title = {{Endangered by the language but saved by the compiler: Robust safety via semantic back-translation}}, doi = {10.1145/3776682}, volume = {10}, year = {2026}, } @inproceedings{21042, abstract = {Many blockchains such as Ethereum execute all incoming transactions sequentially significantly limiting the potential throughput. A common approach to scale execution is parallel execution engines that fully utilize modern multi-core architectures. Parallel execution is then either done optimistically, by executing transactions in parallel and detecting conflicts on the fly, or guided, by requiring exhaustive client transaction hints and scheduling transactions accordingly. However, recent studies have shown that the performance of parallel execution engines depends on the nature of the underlying workload. In fact, in some cases, only a 60% speed-up compared to sequential execution could be obtained. This is the case, as transactions that access the same resources must be executed sequentially. For example, if 10% of the transactions in a block access the same resource, the execution cannot meaningfully scale beyond 10 cores. Therefore, a single popular application can bottleneck the execution and limit the potential throughput. In this paper, we introduce Anthemius, a block construction algorithm that optimizes parallel transaction execution throughput. We evaluate Anthemius exhaustively under a range of workloads, and show that Anthemius enables the underlying parallel execution engine to process over twice as many transactions.}, author = {Neiheiser, Ray and Kokoris Kogias, Eleftherios}, booktitle = {29th International Conference on Financial Cryptography and Data Security}, isbn = {9783032070234}, issn = {1611-3349}, location = {Miyakojima, Japan}, pages = {307--323}, publisher = {Springer Nature}, title = {{Anthemius: Efficient and modular block assembly for concurrent execution}}, doi = {10.1007/978-3-032-07024-1_18}, volume = {15751}, year = {2026}, } @article{21045, abstract = {The abundant population of little red dots (LRDs), compact objects with red UV to optical colors and broad Balmer lines at high redshift, is revealing new insights into the properties of early active galactic nuclei (AGN). Perhaps the most surprising features of this population are the presence of Balmer absorption and ubiquitous strong Balmer breaks. Recent models link these features to an active supermassive black hole (SMBH) cocooned in very dense gas (NH ∼ 1024 cm−2). We present a stringent test of such models using VLT/MUSE observations of A2744-45924, the most luminous LRD known to date (LHα ≈ 1044 erg s−1), located behind the Abell-2744 lensing cluster at z = 4.464 (μ = 1.8). We detect a moderately extended Lyα nebula (h ≈ 5.7 pkpc), spatially offset from the point-like Hα seen by JWST by ≈1.6 pkpc. The Lyα emission is narrow (FWHM = 270 ± 15 km s−1), and faint (Lyα = 0.07Hα) compared to Lyα nebulae typically observed around quasars of similar luminosity. We detect compact N IV]λ1486 emission, spatially aligned with Hα, and a spatial shift in the far-UV continuum matching the Lyα offset. We discuss that Hα and Lyα have distinct physical origins: Hα originates from the AGN, while Lyα is powered by star formation. In the environment of A2744-45924, we identified four extended Lyα halos (Δz < 0.02, Δr < 100 pkpc). Their Lyα luminosities match the expectations based on Hα emission, and show no evidence for radiation from A2744-45924 affecting its surroundings. The lack of strong, compact, and broad Lyα and the absence of a luminous extended halo, suggest that the UV AGN light is obscured by dense gas cloaking the SMBH with a covering factor close to unity.}, author = {Torralba Torregrosa, Alberto and Matthee, Jorryt J and Pezzulli, Gabriele and Urrutia, Tanya and Gronke, Max and Mascia, Sara and D’Eugenio, Francesco and Di Cesare, Claudia and Eilers, Anna Christina and Greene, Jenny E. and Iani, Edoardo and Ishikawa, Yuzo and Mackenzie, Ruari and Naidu, Rohan P. and Navarrete, Benjamín and Kotiwale, Gauri}, issn = {1432-0746}, journal = {Astronomy and Astrophysics}, publisher = {EDP Sciences}, title = {{A weak Ly α halo for an extremely bright little red dot. Indications of enshrouded supermassive black hole growth}}, doi = {10.1051/0004-6361/202555596}, volume = {705}, year = {2026}, } @inbook{21056, abstract = {In this work, we introduce and study what we believe is an intriguing, and, to the best of our knowledge, previously unknown connection between two fundamental areas in computational topology, namely topological data analysis (TDA) and knot theory. Given a function from a topological space to ℝ, TDA provides tools to simplify and study the importance of topological features: in particular, the 𝑙^𝑡⁢ℎ-dimensional persistence diagram encodes the topological changes (or 𝑙-homology) in the sublevel set as the function value increases into a set of points in the plane. Given a continuous one parameter family of such functions, we can combine the persistence diagrams into an object known as a vineyard, which tracks the evolution of points in the persistence diagram as the function changes. If we further restrict that family of functions to be periodic, we identify the two ends of the vineyard, yielding a closed vineyard. This allows the study of monodromy, which in this context means that following the family of functions for a period permutes the set of points in a non-trivial way. Recent work has studied monodromy in the directional persistent homology transform, demonstrating some interesting connections between an input shape and monodromy in the persistent homology transform for 0-dimensional homology embedded in ℝ^2. In this work, given a link and a value 𝑙, we construct a topological space (based on the given link) and periodic family of functions on this space (based on the Euclidean distance function), such that the closed 𝑙-vineyard contains this link. This shows that vineyards are topologically as rich as one could possibly hope, suggesting many future directions of work. Importantly, it has at least two immediate consequences we explicitly point out: 1. Monodromy of any periodicity can occur in a 𝑙-vineyard for any 𝑙. This answers a variant of a question by Arya and collaborators. To exhibit this as a consequence of our first main result we also reformulate monodromy in a more geometric way, which may be of interest in itself. 2. Topologically distinguishing closed vineyards is likely to be difficult (from a complexity theory as well as from a practical perspective) because of the difficulty of knot and link recognition, which have strong connections to many NP-hard problems.}, author = {Chambers, Erin W. and Fillmore, Christopher D and Stephenson, Elizabeth R and Wintraecken, Mathijs}, booktitle = {Proceedings of the 2026 Annual ACM-SIAM Symposium on Discrete Algorithms}, editor = {Green Larsen, Kasper and Saha, Barna}, pages = {6240--6263}, publisher = {Society for Industrial and Applied Mathematics}, title = {{Braiding Vineyards}}, doi = {10.1137/1.9781611978971.225}, year = {2026}, } @inproceedings{21113, abstract = {Causal discovery from i.i.d. observational data is known to be generally ill-posed. We demonstrate that if we have access to the distribution induced by a structural causal model, and additional data from (in the best case) only two environments that sufficiently differ in the noise statistics, the unique causal graph is identifiable. Notably, this is the first result in the literature that guarantees the entire causal graph recovery with a constant number of environments and arbitrary nonlinear mechanisms. Our only constraint is the Gaussianity of the noise terms; however, we propose potential ways to relax this requirement. Of interest on its own, we expand on the well-known duality between independent component analysis (ICA) and causal discovery; recent advancements have shown that nonlinear ICA can be solved from multiple environments, at least as many as the number of sources: we show that the same can be achieved for causal discovery while having access to much less auxiliary information.}, author = {Montagna, Francesco}, booktitle = {The 14th International Conference on Learning Representations}, location = {Rio de Janeiro, Brazil}, publisher = {OpenReview}, title = {{On the identifiability of causal graphs with multiple environments}}, year = {2026}, } @article{21115, abstract = {Quantifying cell morphology is central to understanding cellular regulation, fate, and heterogeneity, yet conventional image-based analyses often struggle with diverse or irregular shapes. We present a computational framework that uses topological data analysis to characterise and compare single-cell morphologies from fluorescence microscopy. Each cell is represented by its contour together with the position of its nucleus, from which we construct a filtration based on a radial distance function and derive a persistence diagram encoding the shape’s topological evolution. The similarity between two cells is quantified using the 2-Wasserstein distance between their diagrams, yielding a shape distance we call the PH distance. We apply this method to two representative experimental systems—primary human mesenchymal stem cells (hMSCs) and HeLa cells—and show that PH distances enable the detection of outliers in those systems, the identification of sub-populations, and the quantification of shape heterogeneity. We benchmark PH against three established contour-based distances (aspect ratio, Fourier descriptors, and elastic shape analysis) and show that PH offers better separation between cell types and greater robustness when clustering heterogeneous populations. Together, these results demonstrate that persistent-homology-based signatures provide a principled and sensitive approach for analysing cell morphology in settings where traditional geometric or image-based descriptors are insufficient.}, author = {Bleile, Yossi and Yadav, Pooja and Koehl, Patrice and Rehfeldt, Florian}, issn = {1553-7358}, journal = {PLoS Computational Biology}, publisher = {Public Library of Science}, title = {{Persistence diagrams as morphological signatures of cells: A method to measure and compare cells within a population}}, doi = {10.1371/journal.pcbi.1013890}, volume = {22}, year = {2026}, } @misc{21116, abstract = {Sex-chromosome systems are highly variable across animals, but how they transition from one to another is not well understood. Diptera have undergone multiple sex-chromosome turnovers and expansions while maintaining their general chromosomal content, which makes them an ideal clade to study such transitions. We analyzed more than 100 dipteran whole-genome assemblies and identified 4 new lineages that underwent sex-chromosome turnover (in addition to the 5 previously reported). We find that the majority of turnovers happened in the group Schizophora, which tend to have fewer genes on Muller element F (the chromosome homologous to the ancestral insect X chromosome) than lower dipterans, a factor previously hypothesized to facilitate turnover. Most derived X chromosomes have higher GC content than autosomes, consistent with a high prevalence of male achiasmy in Diptera. In addition, an excess of gene movement out of the X is detected for most of these new X chromosomes, and many of these moved genes have high testis expression in Drosophila, suggesting that out-of-X gene movement contributes to the long-term demasculinization of X chromosomes.}, author = {Layana Franco, Lorena Alexandra and Toups, Melissa A and Vicoso, Beatriz}, keywords = {Schizophora, sex chromosomes, sex-chromosome turnover, Diptera, genomic features, out-of-X movement.}, publisher = {Institute of Science and Technology Austria}, title = {{Research Data for "Causes and consequences of sex-chromosome turnovers in Diptera"}}, doi = {10.15479/AT-ISTA-21116}, year = {2026}, } @article{21132, abstract = {We unify the variational hypocoercivity framework established by D. Albritton, S. Armstrong, J.-C. Mourrat, and M. Novack [2], with the notion of second-order lifts of reversible diffusion processes, recently introduced by A. Eberle and the second author [30]. We give an abstract, yet fully constructive, presentation of the theory, so that it can be applied to a large class of linear kinetic equations. As this hypocoercivity technique does not twist the reference norm, we can recover accurate and sharp convergence rates in various models. Among those, adaptive Langevin dynamics (ALD) is discussed in full detail and we show that for near-quadratic potentials, with suitable choices of parameters, it is a near-optimal second-order lift of the overdamped Langevin dynamics. As a further consequence, we observe that the Generalised Langevin Equation (GLE) is also a second-order lift, as the standard (kinetic) Langevin dynamics are, of the overdamped Langevin dynamics. Then, convergence of (GLE) cannot exceed ballistic speed, i.e. the square root of the rate of the overdamped regime. We illustrate this phenomenon with explicit computations in a benchmark Gaussian case.}, author = {Brigati, Giovanni and Lörler, Francis and Wang, Lihan}, issn = {1937-5077}, journal = {Kinetic and Related Models}, pages = {34--55}, publisher = {American Institute of Mathematical Sciences}, title = {{Hypocoercivity meets lifts}}, doi = {10.3934/krm.2025020}, volume = {20}, year = {2026}, } @inproceedings{21133, abstract = {Data structures based on trees and tree traversals are ubiquitous in computer systems. Many low-level programs, including some implementations of critical systems like page tables and the web browser DOM, rely on generic tree-traversal functions that traverse tree nodes in a pre-determined order, applying a client-provided operation to each visited node. Developing a general approach to specifying and verifying such traversals is tricky since the client-provided per-node operation can be stateful and may potentially depend on or modify the structure of the tree being traversed. In this paper, we present a recipe for (semi-)automated verification of such generic, stateful tree traversals. Our recipe is (a) general: it applies to a range of tree traversals, in particular, pre-, post- and in-order depth-first traversals; (b) modular: parts of a traversal’s proof can be reused in verifying other similar traversals; (c) expressive: using the specification of a tree traversal, we can verify clients that use the traversal in a variety of different ways; and (d) automatable: many proof obligations can be discharged automatically. At the heart of our recipe is a novel use of tree zippers to represent a logical abstraction of the tree traversal state, and zipper transitions as an abstraction of traversal steps. We realize our recipe in the RefinedC framework in Rocq, which allows us to verify a number of different tree traversals and their clients written in C.}, author = {Elbeheiry, Laila and Sammler, Michael Joachim and Krebbers, Robbert and Dreyer, Derek and Garg, Deepak}, booktitle = {Proceedings of the 15th ACM SIGPLAN International Conference on Certified Programs and Proofs}, isbn = {9798400723414}, location = {Rennes, France}, pages = {339--352}, publisher = {Association for Computing Machinery}, title = {{A recipe for modular verification of generic tree traversals}}, doi = {10.1145/3779031.3779110}, year = {2026}, } @inproceedings{21135, abstract = {Three-dimensional (3D) microscopy data is often anisotropic with significantly lower resolution (up to 8x) along the z axis than along the xy axes. Computationally generating plausible isotropic resolution from anisotropic imaging data would benefit the visual analysis of large-scale volumes. This paper proposes niiv, a self-supervised method for isotropic reconstruction of 3D microscopy data that can quickly produce images at arbitrary output resolutions. The representation embeds a learned latent code within a neural field that describes the implicit higher-resolution isotropic image region. We use an attention-guided latent interpolation approach, which allows flexible information exchange over a local latent neighborhood. Under isotropic volume assumptions, we self-supervise this representation on low-/high-resolution lateral image pairs to reconstruct an isotropic volume from low-resolution axial images. We evaluate our method on simulated and real anisotropic electron (EM) and light microscopy (LM) data. Compared to diffusion-based baselines, niiv shows improved reconstruction quality (+1 dB PSNR) and is over three orders of magnitude faster (1,000x) to infer. Specifically, niiv reconstructs a 128^3 voxel volume in 2/10th of a second, renderable at varying (continuous) high resolutions for display. Our code is available at https://github.com/jakobtroidl/niiv-miccai.}, author = {Troidl, Jakob and Liang, Yiqing and Beyer, Johanna and Tavakoli, Mojtaba and Danzl, Johann G and Hadwiger, Markus and Pfister, Hanspeter and Tompkin, James}, booktitle = {1st International Workshop on Efficient Medical Artificial Intelligence}, isbn = {9783032139603}, issn = {1611-3349}, location = {Daejeon, South Korea}, pages = {257--267}, publisher = {Springer Nature}, title = {{niiv: Interactive Self-supervised Neural Implicit Isotropic Volume Reconstruction}}, doi = {10.1007/978-3-032-13961-0_26}, volume = {16318}, year = {2026}, } @inproceedings{21140, abstract = {We consider several problems related to packing forests in graphs. The first one is to find k edge-disjoint forests in a directed graph G of maximal size such that the indegree of each vertex in these forests is at most k. We describe a min-max characterization for this problem and show that it can be solved in almost linear time for fixed k, extending the algorithm of [Gabow, 1995]. Specifically, the complexity is O(kδm log n), where n, m are the number of vertices and edges in G respectively, and δ = max{1, k − kG}, where kG is the edge connectivity of the graph. Using our solution to this problem, we improve complexities for two existing applications:(1) k-forest problem: find k forests in an undirected graph G maximizing the number of edges in their union. We show how to solve this problem in O(k3 min{kn, m} log2 n + k · MAXFLOW(m, m) log n) time, breaking the Ok(n3/2) complexity barrier of previously known approaches.(2) Directed edge-connectivity augmentation problem: find a smallest set of directed edges whose addition to the given directed graph makes it strongly k-connected. We improve the deterministic complexity for this problem from O(kδ(m + δn) log n) [Gabow, STOC 1994] to O(kδm log n). A similar approach with the same complexity also works for the undirected version of the problem.}, author = {Arkhipov, Pavel and Kolmogorov, Vladimir}, booktitle = {Proceedings of the 2026 Annual ACM-SIAM Symposium on Discrete Algorithms}, location = {Vancouver, Canada}, pages = {4023--4042}, publisher = {Society for Industrial and Applied Mathematics}, title = {{Faster algorithms for packing forests in graphs and related problems}}, doi = {10.1137/1.9781611978971.148}, year = {2026}, } @misc{21145, abstract = {Protein conformational energy landscapes are shaped not only by intramolecular interactions but also by their environment. In protein crystals and protein-protein complexes, intermolecular contacts alter this energy landscape, but the exact nature of this alteration is difficult to decipher. Understanding how the crystal lattice affects protein dynamics is crucial for crystallography-based studies of motion, yet its influence on collective motions remains unclear. Aromatic ring flips in the hydrophobic core represent sensitive probes of such dynamics. Here, we compare the kinetics of aromatic ring flips in the protein GB1 in crystals, in complex with its binding partner IgG, and in solution, combining advanced isotope labeling with quantitative NMR methods. We show that rings in the core flip nearly a thousand times less frequently in crystals than in solution. Enhanced-sampling molecular dynamics simulations, based on a new crystal structure, reproduce these elevated barriers and reveal how the crystal restrains motions. }, author = {Becker, Lea Marie and Schanda, Paul and Chipot, Christophe}, publisher = {Institute of Science and Technology Austria}, title = {{Additional Data for "Aromatic Ring Flips Reveal Reshaping of Protein Dynamics in Crystals and Complexes"}}, doi = {10.15479/AT-ISTA-21145}, year = {2026}, } @article{21149, abstract = {We present a general theoretical framework for helical dichroism (HD), establishing an explicit link between chiral resolution and orbital angular momentum (OAM) exchange in light–matter interaction. Tracing microscopic mechanisms of the OAM transfer, we derive rotational selection rules, which establish that HD emerges only from the spin–orbit coupling of light, even for beams without the far-field OAM. Our findings refine the conditions for observing HD, provide a tool to re-examine the outcome of prior experiments, and guide future designs for chiral sensing with structured light.}, author = {Hrast, Mateja and Koutentakis, Georgios and Maslov, Mikhail and Lemeshko, Mikhail}, issn = {1079-7114}, journal = {Physical Review Letters}, number = {5}, publisher = {American Physical Society}, title = {{Bottom-up analysis of rovibrational helical dichroism}}, doi = {10.1103/fkf1-1jml}, volume = {136}, year = {2026}, } @article{21158, abstract = {Vernalization-regulated flowering is vital for wheat yield and geographical distribution, and the diversity of flowering time genes is essential for the breeding of climate-resilient varieties. Sugars have long been recognized in regulating flowering; however, the intrinsic connection between carbohydrate metabolism and vernalization response remains largely unexplored. Here, we identify a fructose 1,6-bisphosphate aldolase (FBA) encoding gene, HtL1/FBA10, as a modulator of heading time variation based on a genome-wide association study utilizing wheat core germplasm collections. Evolutionary analysis shows a decrease in the proportion of haplotype-2 of HtL1, which is linked to delayed flowering, in Chinese and American wheat varieties compared to landraces. Vernalization reduces HtL1/FBA10 phosphorylation levels and increases its O-GlcNAcylation, which in turn enhances its enzymatic activity and facilitates VERNALIZATION 1 (VRN1) transcription by regulating histone acetylation at the VRN1 locus. Our findings provide mechanistic insights into the interplay between glucose metabolism and the epigenetic regulation of vernalization in winter wheat.}, author = {Yang, Pengfang and Liu, Yangyang and Dong, Qi and Miao, Yuting and Zhang, Jianlong and Xu, Shujuan and Zhao, Hong and Niu, Yuda and Zhang, Xueyong and Xu, Yunyuan and Guo, Zifeng and Xing, Lijing and Chong, Kang}, issn = {2041-1723}, journal = {Nature Communications}, publisher = {Springer Nature}, title = {{O-GlcNAc and phosphorylation modifications on HtL1/FBA10 regulate wheat vernalization for flowering}}, doi = {10.1038/s41467-025-67734-0}, volume = {17}, year = {2026}, } @article{21159, abstract = {One of the foundational theorems of extremal graph theory is Dirac’s theorem, which says that if an n-vertex graph G has minimum degree at least n/2, then G has a Hamilton cycle, and therefore a perfect matching (if n is even). Later work by Sárközy, Selkow and Szemerédi showed that in fact Dirac graphs have many Hamilton cycles and perfect matchings, culminating in a result of Cuckler and Kahn that gives a precise description of the numbers of Hamilton cycles and perfect matchings in a Dirac graph G (in terms of an entropy-like parameter of G). In this paper we extend Cuckler and Kahn’s result to perfect matchings in hypergraphs. For positive integers d < k, and for n divisible by k, let md (k, n) be the minimum d-degree that ensures the existence of a perfect matching in an n-vertex k-uniform hypergraph. In general, it is an open question to determine (even asymptotically) the values of md (k, n), but we are nonetheless able to prove an analogue of the Cuckler–Kahn theorem, showing that if an n-vertex k-uniform hypergraph G has minimum d-degree at least (1+γ )md (k, n) (for any constantγ > 0), then the number of perfect matchings in G is controlled by an entropy-like parameter of G. This strengthens cruder estimates arising from work of Kang–Kelly–Kühn–Osthus–Pfenninger and Pham–Sah–Sawhney–Simkin.}, author = {Kwan, Matthew Alan and Safavi Hemami, Roodabeh and Wang, Yiting}, issn = {1439-6912}, journal = {Combinatorica}, publisher = {Springer Nature}, title = {{Counting perfect matchings in Dirac hypergraphs}}, doi = {10.1007/s00493-025-00194-8}, volume = {46}, year = {2026}, } @article{21160, abstract = {Context. AM Canum Venaticorum (AM CVn) stars are ultra-compact binary systems composed of a white dwarf primary accreting from a hydrogen-deficient donor. They play a crucial role in astrophysics as potential progenitors of Type Ia supernovae and as laboratories for gravitational wave studies. However, their formation and evolutionary history remain incomplete. Three formation channels have been discussed in the literature: the white dwarf, He-star, and cataclysmic variable channels. Aims. The chemical composition of the accretor atmosphere reflects the material transferred from the donor. In this work we took the first accurate measurements of the fundamental parameters of the accreting white dwarf in ZTF J225237.05−051917.4, including the abundances of key elements such as carbon, nitrogen, and silicon, by analysing ultraviolet spectra obtained with the Hubble Space Telescope (HST). These measurements provide new insight into the evolutionary history of the system and, together with existing optical observations, establish it as a benchmark to develop our pipeline, paving the way for its application to a larger sample of AM CVn systems. Methods. We determined the binary parameters through photometric analysis and constrained the atmospheric parameters of the white dwarf accretor, including its effective temperature, surface gravity, and chemical abundances, by fitting the HST ultraviolet spectrum with synthetic spectral models. We then inferred the system’s formation channel by comparing the results with theoretical evolutionary models. Results. According to our measurements, the accretor’s effective temperature (Teff) is 23 300 ± 600 K and the surface gravity (log g) is 8.4 ± 0.3, which imply an accretor mass (MWD) of 0.86 ± 0.16 M⊙. We find a high nitrogen-to-carbon abundance ratio by mass of > 153. Conclusions. The accretor is significantly hotter than previous estimates based on simplified blackbody fits to the spectral energy distribution, underscoring the importance of detailed spectral modelling for accurately determining system parameters. Our results show that ultraviolet spectroscopy is well suited to constraining the formation channels of AM CVn systems. Of the three proposed formation channels, the He-star channel can be excluded given the high nitrogen-to-carbon ratio. Our results are consistent with both the white dwarf and cataclysmic variable channels.}, author = {Yu, W. and Pala, A. F. and Kupfer, T. and Gänsicke, B. T. and Koester, D. and Belloni, D. and Wong, T. L.S. and Schreiber, M. R. and van Roestel, Joannes C and Brown, A. J. and Waagen, E. O. and González-Carballo, J. L. and Bednarz, S. and Bernacki, K. and De Martino, D. and Fernández Mañanes, E. and González Farfán, R. and Green, M. J. and Groot, P. J. and Hambsch, F. J. and Knigge, C. and Martin-Velasco, J. L. and Morales-Aimar, M. and Myers, G. and Naves Nogues, R. and Poggiani, R. and Popowicz, A. and Ramsay, G. and Reina-Lorenz, E. and Rodríguez-Gil, P. and Salto-González, J. L. and Sion, E. M. and Steeghs, D. and Szkody, P. and Toloza, O. and Tovmassian, G.}, issn = {1432-0746}, journal = {Astronomy and Astrophysics}, publisher = {EDP Sciences}, title = {{The evolutionary history of ultra-compact accreting binaries: I. Chemical abundances and the formation channel of the eclipsing AM CVn system ZTF J225237.05-051917.4 from HST spectroscopy}}, doi = {10.1051/0004-6361/202557568}, volume = {706}, year = {2026}, }