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Given a multivariable polynomial with integer coefficients, what is the probability that it takes a squarefree value? This was determined by Granville and Poonen assuming the ABC conjecture, but an unconditional proof remains unknown. We will start the talk by discussing a paper by Bhargava, Shankar and Wang that unconditionally determines a result for the discriminants of monic polynomials of any given degree. In the second part of the talk, we will see how the methods of BSW can be interpreted into a more general framework developed by Thorne, and how they can be used to obtain new results for other families of discriminant polynomials.

• Speaker: Marti Oller Riera (Cambridge)
• Tuesday 04 February 2025, 14:30-15:30
• Venue: MR13.
• Series: Number Theory Seminar; organiser: Rong Zhou.

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The talk will provide an overall introduction about the origin of the EU AI Act, the context in which the legislation evolved and its main components. Considering the high degree of complexity of the legal text, the presentation aims to break it down by offering insight into the rationale of the choices that were made and help the audience gather an initial understanding of the scope and potential impact.

Link to join virtually: https://cam-ac-uk.zoom.us/j/87421957265

This talk is being recorded. If you do not wish to be seen in the recording, please avoid sitting in the front three rows of seats in the lecture theatre. Any questions asked will also be included in the recording. The recording will be made available on the Department’s webpage

• Speaker: Dr Gabriele Mazzini - Research Affiliate, MIT Media Lab. Architect & lead author of the EU AI Act
• Wednesday 05 February 2025, 15:05-15:55
• Venue: Lecture Theatre 1, Computer Laboratory, William Gates Building.
• Series: Wednesday Seminars - Department of Computer Science and Technology ; organiser: Ben Karniely.

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This article presents an innovative approach to developing pH-responsive thiopyrylium-based NIR-II fluorophores with enhanced photoacoustic and photodynamic properties. By precisely modulating molecular aggregation, the study demonstrates significant advances in tumor-targeted dual-modal imaging and therapy, providing a promising pathway for future cancer diagnosis and treatment.

Aggregation profoundly influences the photophysical properties of molecules. Here, a new series of thiopyrylium-based hemicyanine near-infrared II (NIR-II) fluorophores is developed by meticulously adjusting their aggregation states. Notably, the star molecule HTPA exhibits a remarkable pH-responsive behavior and a significant increase in photoacoustic (PA) intensity when aggregated. Additionally, their behavior and pH reversibility during aggregation formation are systematically investigated, including computational optimization, femtosecond transient absorption spectroscopy, NMR analysis, and single crystal analysis. Finally, an innovative “off ” nanoparticle specifically is designed for effective tumor-targeted PA/NIR-II dual-modal imaging and photodynamic therapy by utilizing a pH-responsive polymer. The signal-to-background ratio (SBR) of PA signals significantly increased to 169 in the region of interest (ROI) in the mouse model when irradiated at 1064 nm. These findings not only provide a promising avenue for future studies of NIR-II small molecules but also pave the way for significant advances in the field of integrated cancer diagnosis and therapy.

Inferring model parameters from observational data of a physical system is the setup for many inverse problems. Solving these kinds of problems can give key insight into the state of a system for quantities that are not directly observable, such as material properties. In this talk, we discuss a population-based perspective on solving inverse problems where the data available comes from a collection of physical systems and we are interested in characterising the (indirectly observable) properties of these systems at a distributional level. We call this: calibrating priors from indirect data. Furthermore, we show how this can be accomplished while concurrently learning ML-based surrogates which capture the behaviour of the physical systems of interest.

• Speaker: Arnaud Vadeboncoeur, University of Cambridge
• Friday 07 February 2025, 15:00-16:00
• Venue: CivEng Seminar Room (1-33) (Civil Engineering Building).
• Series: Engineering Department Structures Research Seminars; organiser: Shehara Perera.

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Abstract not available

• Speaker: Speaker to be confirmed
• Wednesday 26 February 2025, 15:30-16:30
• Venue: BAS Seminar Room 1.
• Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Birgit Rogalla.

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Abstract not available

• Speaker: Speaker to be confirmed
• Wednesday 23 April 2025, 14:00-15:00
• Venue: BAS Seminar Room 330b.
• Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Birgit Rogalla.

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Abstract not available

• Speaker: Speaker to be confirmed
• Wednesday 09 April 2025, 14:00-15:00
• Venue: BAS Seminar Room 2.
• Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Birgit Rogalla.

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Abstract not available

• Speaker: Speaker to be confirmed
• Wednesday 26 March 2025, 14:00-15:00
• Venue: BAS Seminar Room 330b.
• Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Birgit Rogalla.

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Abstract not available

• Speaker: Speaker to be confirmed
• Wednesday 12 March 2025, 14:00-15:00
• Venue: BAS Seminar Room 2.
• Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Birgit Rogalla.

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Abstract not available

• Speaker: Prof Hong Geun Lee (Seoul National University)
• Thursday 15 May 2025, 14:00-15:00
• Venue: Dept. of Chemistry, Pfizer Lecture Theatre.
• Series: Synthetic Chemistry Research Interest Group; organiser: Jasmine Mitchell.

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An innovative ultralight electrospun nanofiber composite filter, mass-produced via an one-step free surface electrospinning technology, is engineered with a vertical ternary spatial network (TSN) structure, featuring elongated internal aperture channels. This advanced TSN filter excels in high-performance filtration of ultrafine PM0.3 aerosols, while significantly minimizing material usage. It is designed for recyclability and operates with low energy requirements, ensuring both wearer comfort and environmental sustainability.

Air pollutants, particularly highly permeable particulate matter (PM), threaten public health and environmental sustainability due to extensive filter media consumption. Existing melt-blown nonwoven filters struggle with PM0.3 removal, energy consumption, and disposal burdens. Here, an ultralight composite filter with a vertical ternary spatial network (TSN) structure that saves ≈98% of raw material usage and reduces fabrication time by 99.4%, while simultaneously achieving high-efficiency PM0.3 removal (≥99.92%), eco-friendly regeneration (near-zero energy consumption), and enhanced wearing comfort (breathability >80 mm s⁻¹, infrared transmittance >85%), is reported. The TSN filter consists of a hybrid layer of microspheres (average diameter ≈1 µm)/superfine nanofibers (≈20 nm) sandwiched between two nanofiber scaffolds (diameter ≈400 nm and ≈100 nm). This arrangement offers high porosity (≈85%), ultralow areal density (<1 g m−2), alow airflow resistance (<90 Pa), guaranteeing superb thermal comfort. Notably, utilizing scalable one-step free surface electrospinning technology, TSN mats can be mass-produced at a rate of 60 meters per hour (width of 1.6 meters), which is critical and verified for various applications including window screens, individual respiratory protectors, and dust collectors. This work provides a viable strategy for designing high-performance nanofiber filter media through structural regulation in a scalable, cost-effective, and sustainable way.

PEA2PbBr4 is a promising scintillator for γ-rays and nf detection. However, its energy resolution in γ-rays detection is poor and the ability to discriminate nf/γ-rays has not been accurately reported. It is demonstrated that Zn2+ and Sb3+ doping enhances light yield and optimizes luminescence. Improved scintillator achieves 4.84% and 5.65% energy resolution at 662 keV and effective discrimination in γ-rays/nf detection.

Organic-inorganic halide 2D perovskite single crystals have recently emerged as promising scintillators for gamma (γ) rays and fast neutrons (nf) detection. However, their energy resolution in γ-rays detection still significantly lags behind that of perovskite semiconductor detectors. Improving crystal defects and enhancing light yield to optimize light output detected by the photomultiplier tube are crucial strategies for addressing this issue. Herein, it is demonstrated that Zn2+ and Sb3+ cation interstitial doping strategy can effectively reduce internal defects within the phenylethylammonium lead bromide (PEA2PbBr4) crystal by regulating lattice expansion. This approach also suppresses light loss caused by exciton-exciton annihilation and accelerates electron-hole recombination processes, optimizing both the luminescence intensity and decay lifetime of the scintillator. The Zn2+ and Sb3+ doping PEA2PbBr4 scintillator achieve an optimal energy resolution of 4.84% and 5.65% at 662 keV for the photopeak, respectively. Additionally, in the 241Am-Be field, effective identification of nf and γ-rays around 1100 keVee is achieved using a pulse shape discrimination (PSD) method, with the figure of merit (FOM) being 0.85 and 1.03, respectively. This work provides a reliable new approach for optimizing the scintillation performance of 2D perovskite and promotes the application of 2D perovskite scintillator in γ-rays and nf detection.

The challenges of constructing heterogeneous catalysts with high metal loading, precise structures, and stability are overcome by proposing a stepwise targeted coordination engineering strategy. This approach allows for the co-anchoring of Pt single atoms and Au25(SG)18 nanoclusters on g-C3N4 and the resulting dual-site catalysts demonstrate remarkable electrochemical reduction capabilities and enhanced stability throughout the catalytic process.

Dual-site catalysts hold significant promise for accelerating complex electrochemical reactions, but a major challenge remains in balancing high loading with precise dual-site architecture to achieve optimal activity, stability, and specificity simultaneously. Herein, a strategy of stepwise targeted coordination engineering is introduced to co-anchor Pt single atoms (Pt1, 1.41 wt.%) and Au25(SG)18 nanoclusters (Au25, 18.92 wt.%) with high loadings on graphitic carbon nitride (g-C3N4). This approach ensures that Pt1 and Au25 occupy distinct surface sites on the g-C3N4 substrate, providing excellent stability and unprecedented electrochemical activity. In the catalysis of As(III), a sensitivity of 8.32 µA ppb−1 is achieved, more than double the previously reported values under neutral conditions. The enhanced detection limit (0.2 ppb) is crucial for monitoring water quality and protecting public health from arsenic contamination, a significant environmental and health risk. Furthermore, the formation of Pt─As and As─S bonds facilitates the easier breakage of As─O bonds, thereby lowering the reaction barrier energy of the rate-determining step and significantly enhancing arsenious acid catalysis efficiency. These results not only offer an intriguing strategy for constructing highly efficient heterogeneous dual-site catalysts but also reveal the atomic-scale catalytic mechanisms that drive enhanced catalytic efficiency.

This review highlights synergies between reticular chemistry and supramolecular chemistry. The role of supramolecular interactions in determining framework…guest interactions and attempts to understand dynamic behavior in metal–organic frameworks (MOFs), particularly emphasizing the development of crystal sponges, studying reactions in frameworks and attempts to control pore behavior through the incorporation of mechanically-interlocked molecules, is explored.

Far from being simply rigid, benign architectures, metal–organic frameworks (MOFs) exhibit diverse interactions with their interior environment. From developing crystal sponges to studying reactions in framework materials, the role of both supramolecular chemistry and framework structure is evident. We explore the role of supramolecular chemistry in determining framework…guest interactions and attempts to understand the dynamic behavior in MOFs, including attempts to control pore behavior through the incorporation of mechanically-interlocked molecules. Appreciating and understanding the role of supramolecular interactions and dynamic behavior in metal–organic frameworks emerge as important directions for the field.

A spherical core-shell nanomotor consisting of a polydopamine-indocyanine green composite shell and a rigid functional core is proposed in this work. This motor can be activated by the NIR-I irradiation to perform NIR-II imaging-directed thermoplastic propulsion in subcutaneous tissue, enabling an efficient peritumoral administration for low-risk superficial tumor photothermal therapy.

Peritumoral subcutaneous injection has been highly envisioned as an efficient yet low-risk administration of photothermal agents for superficial tumor photothermal therapy. However, obstructed by complex subcutaneous tissue, the delivery of injected photothermal agents to the specific tumor remains a critical issue. Herein, the study reports a polydopamine (PDA)-encapsulated spherical core/shell nanomotor with fluorescent indocyanine green (ICG) immobilized on its PDA shell. Upon the first near-infrared (NIR-I) irradiation, this motor can generate favorable photothermal heat, and meantime, emit a robust ICG fluorescence in the second near-infrared window (NIR-II). The heat turns the motor into an active photothermal agent able to perform thermophoretic propulsion along the irradiation direction in subcutaneous tissue, while the ICG fluorescence can direct the subcutaneous propulsion of motors toward specific tumor through real-time NIR-II imaging. These functions endow the motor with the ability of moving to tumor after being injected at peritumoral site, enabling an enhanced photothermal therapy (PTT). The results demonstrated herein suggest an integrated nanorobotic tool for the superficial PTT using peritumoral administration, highlighting an NIR-II imaging-directed subcutaneous propulsion.

This work explores the MOF landscape to select a single, optimal candidate for successfully delivering cancer drugs (gemcitabine, paclitaxel, SN-38) into tough pancreatic tumors. Machine learning and simulations guide this search, demonstrating colloidal stability, excellent biocompatibility, cellular uptake, and sustained release. With long-term stability, the paclitaxel-loaded hydrogel formulation achieves remarkable in vivo results, shrinking tumors and reducing metastasis.

Despite improvements in cancer survival rates, metastatic and surgery-resistant cancers, such as pancreatic cancer, remain challenging, with poor prognoses and limited treatment options. Enhancing drug bioavailability in tumors, while minimizing off-target effects, is crucial. Metal–organic frameworks (MOFs) have emerged as promising drug delivery vehicles owing to their high loading capacity, biocompatibility, and functional tunability. However, the vast chemical diversity of MOFs complicates the rational design of biocompatible materials. This study employed machine learning and molecular simulations to identify MOFs suitable for encapsulating gemcitabine, paclitaxel, and SN-38, and identified PCN-222 as an optimal candidate. Following drug loading, MOF formulations are improved for colloidal stability and biocompatibility. In vitro studies on pancreatic cancer cell lines have shown high biocompatibility, cellular internalization, and delayed drug release. Long-term stability tests demonstrated a consistent performance over 12 months. In vivo studies in pancreatic tumor-bearing mice revealed that paclitaxel-loaded PCN-222, particularly with a hydrogel for local administration, significantly reduced metastatic spread and tumor growth compared to the free drug. These findings underscore the potential of PCN-222 as an effective drug delivery system for the treatment of hard-to-treat cancers.

In view of the abnormal nutrient requirements of tumor cells and tumor tissues, this study focuses on the nutrient and metabolic characteristics of tumor cells and other cell members of the tumor microenvironment and summarizes relevant nutrient deprivation strategies based on targeted technologies, which is of great significance for the development of new nutrition-targeted anti-cancer therapies.

Higher and richer nutrient requirements are typical features that distinguish tumor cells from AU: cells, ensuring adequate substrates and energy sources for tumor cell proliferation and migration. Therefore, nutrient deprivation strategies based on targeted technologies can induce impaired cell viability in tumor cells, which are more sensitive than normal cells. In this review, nutrients that are required by tumor cells and related metabolic pathways are introduced, and anti-tumor strategies developed to target nutrient deprivation are described. In addition to tumor cells, the nutritional and metabolic characteristics of other cells in the tumor microenvironment (including macrophages, neutrophils, natural killer cells, T cells, and cancer-associated fibroblasts) and related new anti-tumor strategies are also summarized. In conclusion, recent advances in anti-tumor strategies targeting nutrient blockade are reviewed, and the challenges and prospects of these anti-tumor strategies are discussed, which are of theoretical significance for optimizing the clinical application of tumor nutrition deprivation strategies.

Promotion of C─C Coupling in electrochemical reduction of CO2 to valuable C2+ products is reviewed from microcosmic to macroscopic. The discussed advances and outstanding challenges in the strategies of efficient catalyst design, the influence of local environment in electrolyte, and the design of potential industrial flow cells provided the guidelines for future research in promoted C─C coupling from foundation to application.

The electrochemical CO2 reduction reaction (CO2RR) to valuable C2+ products emerges as a promising strategy for converting intermittent renewable energy into high-energy-density fuels and feedstock. Leveraging its substantial commercial potential and compatibility with existing energy infrastructure, the electrochemical conversion of CO2 into multicarbon hydrocarbons and oxygenates (C2+) holds great industrial promise. However, the process is hampered by complex multielectron-proton transfer reactions and difficulties in reactant activation, posing significant thermodynamic and kinetic barriers to the commercialization of C2+ production. Addressing these barriers necessitates a comprehensive approach encompassing multiple facets, including the effective control of C─C coupling in industrial electrolyzers using efficient catalysts in optimized local environments. This review delves into the advancements and outstanding challenges spanning from the microcosmic to macroscopic scales, including the design of nanocatalysts, optimization of the microenvironment, and the development of macroscopic electrolyzers. By elucidating the influence of the local electrolyte environment, and exploring the design of potential industrial flow cells, guidelines are provided for future research aimed at promoting C─C coupling, thereby bridging microscopic insights and macroscopic applications in the field of CO2 electroreduction.

This study presents the first synthesis of 2D hexagonal Eu₂SO₂ and tetragonal Eu₂SO₆ with tunable dielectric properties. Eu₂SO₂ offers high dielectric performance, while Eu₂SO₆ provides a wider bandgap. Integrated into MoS₂ field-effect transistors, these materials demonstrate excellent performance, highlighting their potential as multifunctional dielectrics for next-generation low-power electronics.

Advancing next-generation electronics necessitates precise control of dielectric properties in 2D materials. Here, the first synthesis of novel 2D quasi-van der Waals (vdW) europium oxysulfur (Eu2SOx) compounds, comprising hexagonal Eu₂SO₂ and tetragonal Eu₂SO₆ phases, with composition-tunable dielectric properties, is presented. Using a homodiffusive-controlled epitaxial growth method, materials are achieved with complementary characteristics: the hexagonal Eu₂SO₂ phase exhibits a high dielectric constant (≈30) paired with a moderate bandgap (≈4.56 eV), while the tetragonal Eu₂SO₆ phase offers a wider bandgap (≈5.62 eV) but a lower dielectric constant (≈20). The potential of these materials is demonstrated by integrating ultrathin Eu₂SO₂ nanoplates with molybdenum disulfide (MoS₂) field-effect transistors (FETs) via vdW forces. The resulting devices achieve a near-ideal I on/I off ratio (≈10⁸), minimal hysteresis (≈5.3 mV), a low subthreshold slope (≈63.5 mV dec⁻¹), and ultralow leakage current (≈10⁻¹⁴ A). These results highlight the capacity of europium oxysulfur compounds to address the trade-off between dielectric constant and bandgap, offering tailored solutions for diverse 2D electronic applications. This work underscores the potential of composition engineering to expand the family of rare-earth oxysulfur compounds for nanoelectronics, paving the way for innovative gate dielectrics in next-generation devices.

The modification of SU5402 (SU) with aliphatic chains containing 20 carbon atoms (SU-C20 NPs) exhibits an exceptional ability to penetrate the ocular barrier and ensure prolonged drug retention within the eye. These optimized prodrug nanoparticles show a remarkable therapeutic effect in choroidal neovascularization (CNV), resulting in minimal hyperfluorescent leakage and the smallest CNV lesion thickness.

Choroidal neovascularization (CNV) is a prevalent cause of vision impairment. The primary treatment for CNV involves intravitreal injections of anti-vascular endothelial growth factor antibodies. Nevertheless, this approach still faces numerous limitations like poor patient compliance, high therapy expenditure and lack of response in some individuals. Herein, a series of anti-neovascularization prodrugs, SU5402 (SU), modified with lipids of varying chain lengths (C12, C16, C20, C24, C28) is synthesized (SU-C12, SU-C16, SU-C20, SU-C24, SU-C28). 1% polyvinyl alcohol (PVA) is used as a stabilizer to create nanoformulations of five prodrugs named SU-C12 NPs, SU-C16 NPs, SU-C20 NPs, SU-C24 NPs, SU-C28 NPs. Among these, SU-C20 NPs significantly prolong the retention of bioactive drug in the eye for up to 70 d. Moreover, SU-C20 NPs demonstrate superior tissue permeability via enhanced cellular endocytosis and exocytosis. With its prolonged retention and improved penetration, SU-C20 NPs reduce the fluorescence intensity of fundus leakage by 42.5% and the fluorescence area by 51.5% in CNV mice after four weeks, effectively inhibiting the progression of CNV. Altogether, small molecule drug SU is innovatively modified to improve its effectiveness for treating fundus neovascular diseases, proposing an alternative therapy for wet age-related macular degeneration (wAMD).