Nanoscience News (<front>)

Nature Materials, Published online: 24 March 2025; doi:10.1038/s41563-025-02162-5

Extracellular anisotropic stresses trigger fibroblast transition into myofibroblasts by the mechanical self-reinforcement of cell–extracellular matrix interactions.

Nature Materials, Published online: 24 March 2025; doi:10.1038/s41563-025-02170-5

The authors review the mechanisms of resistive switching in monolayer and bulk forms of two-dimensional layered materials, providing insights into atomic motions and electronic transport across interfaces.

Nature Materials, Published online: 24 March 2025; doi:10.1038/s41563-025-02180-3

Exploiting the intrinsic response of magic-angle twisted bilayer graphene to resonant terahertz radiation, the interplay between electron interactions and quantum geometry is studied in such flat-band systems.

Nature Materials, Published online: 24 March 2025; doi:10.1038/s41563-025-02185-y

A superlattice structure of gold tetrahedra formed via a surface-promoted pathway is reported. The octo-diamond crystal is achiral, but exhibits bilayers of left- and right-handed chiral motifs with chiroptical plasmonic responses.

Nature Nanotechnology, Published online: 24 March 2025; doi:10.1038/s41565-025-01895-3

A graphene-nanopocket-protected pure Pt nanocatalyst has been reported for heavy-duty-vehicle fuel cells that deliver high power density, high efficiency and exceptional durability with >200,000-h projected lifetime.

Nature Nanotechnology, Published online: 24 March 2025; doi:10.1038/s41565-025-01893-5

Carbon–hydrogen and carbon–deuterium bonding in organic polymers were mapped in real space with single-nanometre spatial resolution using a monochromated transmission electron microscope.

Title to be confirmed

Abstract not available

• Speaker: Jujian Zhang (Imperial College London) and Arnaud Mayeux (The Hebrew University of Jerusalem)
• Thursday 19 June 2025, 17:00-18:00
• Venue: MR14 Centre for Mathematical Sciences.
• Series: Formalisation of mathematics with interactive theorem provers ; organiser: Anand Rao Tadipatri.

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The Chow Ring of the Moduli Stack of Hyperelliptic Prym Pairs

The study of intersection theory on moduli spaces and stacks has a rich history, beginning with Mumford’s seminal 1983 paper, where he introduced the Chow ring with rational coefficients for the moduli space of smooth pointed curves of a given genus and its Deligne–Mumford compactification. This framework was later extended by Vistoli to Deligne–Mumford stacks, by Edidin and Graham to quotient stacks, and more generally by Kresch to both integral and rational coefficients. Since then, extensive research has been devoted to computing the intersection theory of various moduli stacks.

In this talk, we will focus on the integral version of Chow rings, which is generally less well understood. I will first review some known results in this direction. I will then outline the computation of the integral Chow ring of the moduli stack of hyperelliptic Prym curves, which are étale double covers of hyperelliptic curves—a result that Alessio Cela and I recently obtained. In the case of genus two, our results recover a previous computation by Cela and Lopez.

• Speaker: Alberto landi, Brown University
• Friday 28 March 2025, 14:15-15:15
• Venue: CMS MR13.
• Series: Algebraic Geometry Seminar; organiser: Dhruv Ranganathan.

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Irreducibility of Severi varieties on toric surfaces

Severi varieties parametrize integral curves of fixed geometric genus in a given linear system on a surface. In this talk, I will discuss the classical question of whether Severi varieties are irreducible and its relation to the irreducibility of other moduli spaces of curves. I will indicate how tropical methods can be used to answer such irreducibility questions. The new results are from ongoing joint work with Xiang He and Ilya Tyomkin.

• Speaker: Karl Christ, Università degli studi di Torino
• Tuesday 25 March 2025, 14:15-15:15
• Venue: CMS MR13.
• Series: Algebraic Geometry Seminar; organiser: Dhruv Ranganathan.

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Brill-Noether loci of pencils with prescribed ramification

The geometry of curves carrying pencils with prescribed ramification is regulated by the so called adjusted Brill-Noether number. In this talk I will discuss the problem of existence and dimension of Brill-Noether varieties in this context and compare it to the classical one without imposed ramification. The new results are based on joint work with Andreas Leopold Knutsen.

• Speaker: Sara Torelli, Università degli studi di Torino.
• Tuesday 25 March 2025, 10:00-11:00
• Venue: CMS MR13.
• Series: Algebraic Geometry Seminar; organiser: Dhruv Ranganathan.

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Woe is Me!: Spatial Logic and Memory in the OIMOI Inscriptions of Selinous

In the ancient Greek city-state of Selinous in Sicily, there is a unique set of funerary inscriptions which directly lament the fate of the deceased. This formula lacks precedent elsewhere in the Greek world, and I explore how the content of these inscriptions interact with the space on which they are laid out, the memorial stones themselves, and the surrounding landscape. I argue that the negative space employed in many of the inscriptions speaks just as forcefully as the text itself, and that it renders memory in terms of absence, not presence.

• Speaker: Campbell Rosener
• Tuesday 20 May 2025, 13:10-14:00
• Venue: Richard King room, Darwin College.
• Series: Darwin College Humanities and Social Sciences Seminars; organiser: Matthew Jones.

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Professor Awen Gallimore, Co-Director of Systems Immunity Research Institute, Cardiff University

This Cambridge Immunology and Medicine Seminar will take place on Thursday 27 March 2025, starting at 4:00pm, in the Ground Floor Lecture Theatre, Jeffrey Cheah Biomedical Centre (JCBC)

Speaker: Professor Awen Gallimore, Co-Director of Systems Immunity Research Institute, Cardiff University

Title: TBC

Host: Maike De La Roche & Tim Halim, CRUK Cambridge Institute

Refreshments will be available following the seminar.

• Speaker: Professor Awen Gallimore, Co-Director of Systems Immunity Research Institute, Cardiff University
• Thursday 27 March 2025, 16:00-17:00
• Venue: Lecture Theatre, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus.
• Series: Cambridge Immunology Network Seminar Series; organiser: Ruth Paton.

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Field-induced Multi-Q⃗ States in a Pyrochlore Heisenberg Magnet

In this talk, I will present a recent work on the J1-J3b classical Heisenberg model on the pyrochlore lattice in the presence of a magnetic field. We construct exact ground states of the model, which are non-coplanar multi-Q⃗ spin configurations with a large magnetic unit cell. Using linear spin wave theory, we show that entropy favours these multi-Q⃗ states at low temperatures in high magnetic fields. This is confirmed by Monte Carlo simulations, which we also use to map out a phase diagram. Lastly, we calculate the zero-temperature dynamical structure factor. Besides the usual Goldstone modes associated with the ordering Q⃗s, we find high-intensity gapless modes at momenta where there are no Bragg peaks.

• Speaker: Cecilie Glittum (Helmholtz-Zentum Berlin)
• Thursday 27 March 2025, 14:00-15:30
• Venue: TCM Seminar Room.
• Series: Theory of Condensed Matter; organiser: Bo Peng.

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Surgical data using LLMs

Abstract not available

• Speaker: Hugo Georgenthum
• Friday 21 March 2025, 17:00-17:45
• Venue: Lecture Theatre 2, Computer Laboratory, William Gates Building.
• Series: Foundation AI; organiser: Pietro Lio.

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Asymmetry in Supposedly Equivalent Facts: Pre-training Bias in Large Language Models

Understanding and mitigating hallucinations in Large Language Models (LLMs) is crucial for ensuring reliable content generation. While previous research has primarily focused on “when” LLMs hallucinate, our work explains “why” and directly links model behaviour to the pre-training data that forms their prior knowledge. Specifically, we demonstrate that an asymmetry exists in the recognition of logically equivalent facts, which can be attributed to frequency discrepancies of entities appearing as subjects versus objects. Given that most pre-training datasets are inaccessible, we leverage the fully open-source OLMo series by indexing its Dolma dataset to estimate entity frequencies. Using relational facts (represented as triples) from Wikidata5M, we construct probing datasets to isolate this effect. Our experiments reveal that facts with a high-frequency subject and a low-frequency object are better recognised than their inverse, despite their logical equivalence. The pattern reverses in low-to-high frequency settings, and no statistically significant asymmetry emerges when both entities are high-frequency. These findings underscore the influential role of pre-training data in shaping model predictions and provide insights for inferring the characteristics of pre-training data in closed or partially closed LLMs.

• Speaker: Zifeng Ding (University of Cambridge)
• Friday 09 May 2025, 12:00-13:00
• Venue: Room FW26 with Hybrid Format. Here is the Zoom link for those that wish to join online: https://cam-ac-uk.zoom.us/j/4751389294?pwd=Z2ZOSDk0eG1wZldVWG1GVVhrTzFIZz09.
• Series: NLIP Seminar Series; organiser: Suchir Salhan.

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“Imaging the Immune System in Tissue Repair”

This Cambridge Immunology and Medicine Seminar will take place on Thursday 8 May 2025, starting at 4:00pm, in the Ground Floor Lecture Theatre, Jeffrey Cheah Biomedical Centre (JCBC)

Speaker: Professor Paul Kubes, Cumming School of Medicine, University of Calgary

Title: “Imaging the Immune System in Tissue Repair”

Abstract: Using a very simple model of tissue injury where a thermal probe is touched to the surface of a tissue and kills about 1000 cells has unveiled a very complex series of immune events that lead to complete repair in tissues like the liver.  Neutrophils enter the site, clear the debris and leave again via the vasculature while monocytes and iNKT cells surround the injury and slowly the monocytes convert to a repair phenotype before entering and working with stellate cells to help to return the structure back to homeostasis.  The outer compartment where the mesothelium has to regrow requires that peritoneal macrophages attach to the injury site take on a repair phenotype with the help of peritoneal mast cells and aid in repair. Some of these same principles apply to chronic injury  and cancer. 

Host: Tim Halim, CRUK Cambridge

Refreshments will be available following the seminar.

• Speaker: Professor Paul Kubes, Cumming School of Medicine, University of Calgary
• Thursday 08 May 2025, 16:00-17:00
• Venue: Lecture Theatre, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus.
• Series: Cambridge Immunology Network Seminar Series; organiser: Ruth Paton.

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The sluggish water-splitting step hinders the advancement of alkaline hydrogen evolution reaction (HER), making the design of efficient water-splitting active sites critical. The MgO x and MoO y on the atomically thin Ru metallene can cooperatively promote the adsorption–dissociation of water molecules, greatly promoting the efficiency of alkaline HER.

Abstract

Ruthenium (Ru) is considered as a promising catalyst for the alkaline hydrogen evolution reaction (HER), yet its weak water adsorption ability hinders the water splitting efficiency. Herein, a concept of introducing the oxygenophilic MgO x and MoO y species onto amorphous Ru metallene is demonstrated through a simple one-pot salt-templating method for the synergic promotion of water adsorption and splitting to greatly enhance the alkaline HER electrocatalysis. The atomically thin MgO x and MoO y species on Ru metallene (MgO x /MoO y -Ru) show a 15.3-fold increase in mass activity for HER at the potential of 100 mV than that of Ru metallene and an ultralow overpotential of 8.5 mV at a current density of 10 mA cm−2. It is further demonstrated that the MgO x /MoO y -Ru-based anion exchange membrane water electrolyzer can achieve a high current density of 100 mA cm−2 at a remarkably low cell voltage of 1.55 V, and exhibit excellent durability of over 60 h at a current density of 500 mA cm−2. In situ spectroscopy and theoretical simulations reveal that the co-introduction of MgO x and MoO y enhances interfacial water adsorption and splitting by promoting adsorption on oxidized Mg sites and lowering the dissociation energy barrier on oxidized Mo sites.

Efficiency and scintillation velocity are critical for high-energy and medical physics. These parameters, typically conflicting in conventional scintillators, are simultaneously optimized by exploiting the giant oscillator strength of CsPbBr3 nanocrystals, leading to radiatively accelerated (multi)excitonic emission with unity efficiency without detrimental light transport losses in polymeric nanocomposites. This opens up interesting developments in fast-timing radiation detection based on colloidal nanocrystals.

Abstract

Efficiency and emission rate are two traditionally conflicting parameters in radiation detection, and achieving their simultaneous maximization can significantly advance ultrafast time-of-flight (ToF) technologies. In this study, it is demonstrated that this goal is attainable by harnessing the giant oscillator strength (GOS) inherent to weakly confined perovskite nanocrystals, which enables superradiant scintillation under mildly cryogenic conditions that align seamlessly with ToF technologies. It is shown that the radiative acceleration due to GOS encompasses both single and multiple exciton dynamics arising from ionizing interactions, further enhanced by suppressed non-radiative losses and Auger recombination at 80 K. The outcome is ultrafast scintillation with 420 ps lifetime and light yield of ≈10 000 photons/MeV for diluted NC solutions, all without non-radiative losses. Temperature-dependent light-guiding experiments on test-bed nanocomposite scintillators finally indicate that the light-transport capability remains unaffected by the accumulation of band-edge oscillator strength due to GOS. These findings suggest a promising pathway toward developing ultrafast nanotechnological scintillators with optimized light output and timing performance.

Atomic layer modulation is instrumental in optimizing catalytic kinetics for obtaining highly active photocatalysts. A precise atomic layer regulation strategy is proposed to realize the individual modulation of the surface In–S layer in ZnIn2S4, which creates deeper hybridized electronic states of Ni 3d–S 3p to optimize H* adsorption/desorption and maximize surface catalytic benefits for the hydrogen evolution reaction.

Abstract

Solar-driven hydrogen production is significant for achieving carbon neutrality but is limited by unsatisfactory surface catalytic reaction kinetics. Layer regulation can impact carrier transmission or catalytic behavior, but the specific effects on the oxygen or hydrogen evolution reaction (OER or HER) remain unclear, and atomic layer level modulation for maxing HER is challenging. Here the distinct roles of modulated Zn–S or In–S surface layers in ZnIn2S4 (ZIS) for the OER and HER, respectively, are disentangled. Moreover, the extensive characterizations and computational results demonstrate that stressful environments enable individual modulation and introduce Ni into the surface In–S layer rather than the easily alterable Zn–S layer, creating deeper hybridized electronic states of Ni 3d–S 3p, optimizing H* adsorption/desorption, and maximizing surface catalytic benefits for the HER. Consequently, the optimized ZIS exhibited a photocatalytic hydrogen production rate of up to 18.19 mmol g−1 h−1, ≈32 times higher than pristine ZIS. This investigation expands the application scenarios of ultrasonic technology and inspires other precise control types, such as defects and crystal plane engineering, etc.

The schematic representation highlights the essential components for developing a 3D bioprinted glioblastoma model. It includes key microenvironmental factors, biomaterials, and crosslinking techniques. The integration of bioprinting strategies with GBM-on-a-chip models enables the creation of dynamic, physiologically relevant models. A Quality-by-Design (QbD) roadmap can ensure consistent 3D bioprinting models focusing on critical bioprinting processes and material properties.

Abstract

Conventional in vitro models fail to accurately mimic the tumor in vivo characteristics, being appointed as one of the causes of clinical attrition rate. Recent advances in 3D culture techniques, replicating essential physical and biochemical cues such as cell–cell and cell–extracellular matrix interactions, have led to the development of more realistic tumor models. Bioprinting has emerged to advance the creation of 3D in vitro models, providing enhanced flexibility, scalability, and reproducibility. This is crucial for the development of more effective drug treatments, and glioblastoma (GBM) is no exception. GBM, the most common and deadly brain cancer, remains a major challenge, with a median survival of only 15 months post-diagnosis. This review highlights the key components needed for 3D bioprinted GBM models. It encompasses an analysis of natural and synthetic biomaterials, along with crosslinking methods to improve structural integrity. Also, it critically evaluates current 3D bioprinted GBM models and their integration into GBM-on-a-chip platforms, which hold noteworthy potential for drug screening and personalized therapies. A versatile development framework grounded on Quality-by-Design principles is proposed to guide the design of bioprinting models. Future perspectives, including 4D bioprinting and machine learning approaches, are discussed, along with the current gaps to advance the field further.