School of Physical Sciences

The Amundsen Sea sector has some of the fastest-thinning ice shelves in Antarctica, caused by high, ocean-driven basal melt rates, which can lead to increased ice stream flow, causing increased sea level rise (SLR) contributions. In this study, we present the results of a new synchronously coupled ice-sheet/ocean model of the Amundsen Sea sector. We use the WAVI ice sheet model to solve for ice velocities and the MITgcm to solve for ice thickness and three-dimensional ocean properties, allowing for full mass conservation in the coupled ice/ocean system. The coupled model is initialised in the present day and run forward under idealised warm and cold ocean conditions with a fixed ice front. We find that Thwaites Glacier dominates the future SLR from the Amundsen Sea sector, with a SLR that is approximately quadratic in time. The future evolution of Thwaites Glacier depends on the life-span of small pinning points that form during the retreat. The rate of melting around these pinning points provides the link between future ocean conditions and the SLR from this sector and will be difficult to capture without a coupled ice/ocean model. Grounding-line retreat leads to a progressively larger Thwaites ice-shelf cavity, leading to a positive trend in total melting, resulting from the increased ice basal surface area. Despite these important sensitivities, Thwaites Glacier retreats even in a scenario with zero ocean-driven melting. This demonstrates that a tipping point may have been passed in these simulations and some SLR from this sector is now committed.

• Speaker: David Bett, British Antarctic Survey
• Wednesday 21 February 2024, 14:00-15:00
• Venue: BAS Seminar Room 2; zoom.
• Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Birgit Rogalla.

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The Cosmic Dawn marks the first star formations and preceded the Epoch-of-Reionization, when the Universe underwent a fundamental transformation propelled by the radiation from these first stars and galaxies. Interferometric 21-cm experiments aim to probe redshifted neutral hydrogen signals from these periods, constraining the conditions of the early Universe. The SKA -LOW instrument of the Square Kilometre Array telescope is envisaged to be the largest and most sensitive radio telescope at m and cm wavelengths. In this talk we present a data analysis pipeline that was used in the SKA Science Data Challenge 3a: Epoch of Reionisation (SKA SDC3a) to process the novel data products expected from the SKA . To determine whether a successful 21-cm detection is possible with the envisaged SKA , we implement predictive foreground and Bayesian Gaussian Process Regression models alongside a foreground avoidance strategy to isolate the 21-cm signal from that of the astrophysical radio frequency (RF) foregrounds.

• Speaker: Yuchen Liu & Oscar O'Hara (Cavendish Astrophysics)
• Tuesday 13 February 2024, 11:15-12:00
• Venue: Coffee area, Battcock Centre.
• Series: Hills Coffee Talks; organiser: Charles Walker.

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The biotech industry has seen an explosion in the development of therapeutic antibodies in the last two decades, and today most of the best-selling drugs are monoclonal antibodies. The advantages of antibodies as therapeutics – namely their high affinity, specificity, potency, stability, manufacturability, and low toxicity – are compelling. Nevertheless, there are many fundamental challenges associated with co-optimizing their key properties due to strong inherent tradeoffs, such as affinity/specificity, affinity/stability, and species cross-reactivity tradeoffs, which greatly impede their development. I will discuss our progress in addressing these challenges in a rational and predictive manner using machine learning, including several examples of multi-objective optimization ranging from antibody drug development to efficient and long-lived brain delivery of IgGs using bispecific antibodies.

• Speaker: Prof Peter M. Tessier, University of Michigan
• Monday 08 April 2024, 14:00-15:00
• Venue: Department of Chemistry, Cambridge, Wolfson Lecture Theatre.
• Series: Biological Chemistry Research Interest Group; organiser: Echo Wu Williamson.

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In this talk I will survey a number of recent results regarding (relative) profinite rigidity of certain groups (3-manifold groups, Coxeter groups, free-by-cyclic groups, Kaehler groups). Here profinite rigidity asks how much of information about a finitely generated residually finite group can be recovered from its finite quotients. From an algebraic geometry viewpoint this is essentially asking when the algebraic fundamental group determines an aspherical projective variety up to biholomorphism (assuming residual finiteness of the topological fundamental group). Much of the input will come from developments around the world of 3-manifold topology, building on the Virtual Fibring Theorem of Agol and Wise. With this in hand (and time permitting) I will discuss work of Wilton—Zalesskii, Wilkes, and Liu on rigidity amongst 3-manifold groups, work of myself and Kudlinska on rigidity amongst free-by-cyclic groups, and work of myself, Llosa Isenrich, Py, Spitler, Stover, and Vidussi on rigidity amongst Kaehler groups.

• Speaker: Sam Hughes (Oxford)
• Wednesday 14 February 2024, 16:00-17:00
• Venue: MR13.
• Series: Differential Geometry and Topology Seminar; organiser: Oscar Randal-Williams.

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A new computational task has been defined and solved over the past 15 years for extended material systems: the analytic fitting of the Born-Oppenheimer potential energy surface as a function of nuclear coordinates under the assumption of medium-range interactions, 5 ~ 10 Å. The resulting potentials are reactive, many-body, with evaluation costs that are on the order of 0.1-10 ms/atom/cpucore (or about 1ms on a GPU for system sizes that fit into memory), and reach accuracies of a few meV/atom when trained specifically for a given system using iterative/active learning methods. Perhaps the most surprising aspect has been the stability of models trained on very diverse training sets across the periodic table. I will show the recently published MACE -MP-0 model that was trained on just 150,000 real and hypothetical inorganic crystals (90% of training set < 70 atoms), but is capable of stable molecular dynamics on any system tested so far without any extra data – including crystals, liquids, surfaces, clusters, molecules, and combinations of all of these.

• Speaker: Professor Gábor Csanyi, University of Cambridge
• Wednesday 14 February 2024, 14:30-15:30
• Venue: Unilever Lecture Theatre, Yusuf Hamied Department of Chemistry.
• Series: Theory - Chemistry Research Interest Group; organiser: Lisa Masters.

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Many strongly correlated electron systems develop ordered phases at low temperatures that can be well understood in terms of an electronic order parameter. At ultra-low temperatures, however, the hyperfine interaction between nuclei and electrons becomes increasingly important, and we have to consider how this affects ordered phases and phase transitions close to T = 0. PrOs4Sb12 is a superconductor below TC = 1.85 K and HC2 = 2.2 T, and develops antiferroquadrupolar (AFQ) order in magnetic fields between 4 T and 14 T. The hyperfine constant of Pr is relatively large at 52 mK and the Pr crystal electric field levels are closely involved in both the superconducting and AFQ phases. To explore the influence of hyperfine interactions on the low temperature behaviour of PrOs4Sb12, we performed magnetic susceptibility measurements as a function of temperature and magnetic field, to temperatures as low as 1 mK. We find that the phase boundaries in this material anomalously develop down to 5 mK. AFQ order is enhanced at low temperature, whereas superconductivity is suppressed. We explain our results in terms of a ground state composed of hybrid nuclear-electronic states with novel low energy excitations: the low temperature quadrupole excitations that develop from these nuclear- electronic states, are considerably modified compared to their higher temperature counterparts. I will discuss how this leads to a novel type of nuclear-electronic quantum critical point at the AFQ transition, with a strongly damped region of criticality. I will also explain how the hyperfine-induced suppression of superconductivity gives insight into a highly unconventional superconducting pairing mechanism.

• Speaker: Prof. Alix McCollam, School of Physics, University College Cork, Ireland
• Thursday 22 February 2024, 11:15-12:30
• Venue: Mott Seminar Room (531), Cavendish Laboratory, Department of Physics.
• Series: Quantum Matter Seminar; organiser: Malte Grosche.

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Abstract not available

• Speaker: Prof Peter Bühlmann (ETH Zurich)
• Thursday 08 May 2025, 12:15-13:15
• Venue: TBC.
• Series: Rouse Ball Lectures; organiser: HoD Secretary, DPMMS.

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The Deep Underground Neutrino Experiment (DUNE) is a next-generation, long-baseline neutrino experiment currently under construction. Critical for constraining systematic uncertainties to facilitate precision measurements of neutrino oscillations is the near detector (ND) complex, which will monitor and characterise the neutrino beam in situ. Mitigation of high event pile-up from the world’s most intense neutrino beam will be facilitated by a modularisation of the detector, combined with state-of-the-art charge and light readout technologies. This talk will describe the novel detector design, commissioning results and status of NDL Ar 2×2 Demonstrator, a prototype of one of near detectors that will record the first DUNE neutrino data using NuMI beam at Fermilab in 2024.

• Speaker: Karolina Wresilo (University of Cambridge)
• Tuesday 13 February 2024, 11:00-12:00
• Venue: Ryle Seminar Room.
• Series: Cavendish HEP Seminars; organiser: Dr Steve Dennis.

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Years of important research has revealed that cells heavily invest in regulating their size. Nevertheless, it has remained unclear why accurate size control is so important. Our recent study using hematopoietic stem cells (HSCs) in vivo indicates that cellular enlargement is causally associated with aging. I present an overview of these findings and their implications. Furthermore, I present a broad literature analysis to evaluate the potential of cellular enlargement as a new aging hallmark and I highlight interesting work showing a correlation between cell size and age-related diseases. Taken together, I will present mounting evidence linking cellular enlargement to aging and age-related diseases.

• Speaker: Jette Lengefeld, University of Helsinki
• Monday 26 February 2024, 12:30-13:30
• Venue: CRUK CI Lecture Theatre.
• Series: Seminars on Quantitative Biology @ CRUK Cambridge Institute ; organiser: Kate Davenport.

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Malaria is a devastating disease that affects over half a million people each year mostly children under five years old and pregnant women. Antimalarial drug discovery by and large is focused on the identification of novel drugs to treat and prevent the disease due to the emergence and spread of Plasmodium strains resistant to existing medicines. In particular arteminisin resistance which has now spread from South East Asia and is firmly established in Africa (as reported at ASTMH in Seattle Oct 2022). The Merck Research Labs (led by Dr. David Olsen) and the Walter and Eliza Hall Institute of Medical Research (WEHI) (led by Prof. Alan Cowman), have teamed up to invent novel drug candidates by targeting the Plasmodium parasite via newly identified essential aspartyl proteases. The team has been greatly assisted in this endeavor with generous funding for the collaboration from the Wellcome Trust (UK). The team was successful at identifying potent dual protease targeting hits that lead to the identification of an important tool compound WM382 with subnanomolar inhibitory potency in vitro. This was accomplished through targeted phenotypic screening and structure-guided medicinal chemistry to optimize orphan (mechanism of action unknown) hit compounds. WM382 was also used to establish impressive in vivo proof-of-concept efficacy not only on blood stage parasitemia but also potent pharmacodynamic effects in the sexual/mosquito and liver stages of replication. Finally, Justin Boddey’s team at WEHI determined that defective parasites under WM382 drug coverage yield some interesting immunological effects in mice in vivo. Further optimization of potency and pharmacokinetic and selectivity profiles resulted in the invention of clinical compound MK-7602, a very potent PMIX /X dual inhibitor with robust in vivo efficacy in mice at the three stages of the malaria parasite lifecycle and excellent off-target activity and resistance profiles.

Publications related to this work: 1. The Invention of WM382 , a Highly Potent PMIX /X Dual Inhibitor toward the Treatment of Malaria (journal cover shown above). 2. Dual Plasmepsin-Targeting Antimalarial Agents Disrupt Multiple Stages of the Malaria Parasite Life Cycle. 3. Basis for drug selectivity of plasmepsin IX and X inhibition for Plasmodium falciparum and vivax.

Bio: Manuel de Lera Ruiz Bio: Manuel de Lera Ruiz received his B.Sc. in Organic Chemistry from the Universidad Autónoma of Madrid in 1997. After completion of his Ph.D. in 2001 from the University of Nottingham, U.K. he joined Professor Leo A. Paquette research labs at Ohio State University as a postdoctoral fellow. In 2003, he started a career in Medicinal Chemistry at Schering-Plough Research Institute in New Jersey. Manuel moved to Merck’s West Point site in 2012 where he worked for three and a half years in Discovery Process Chemistry. In 2016 he moved back to medicinal chemistry at West Point where he is currently a Principal Scientist in Discovery Chemistry co-leading the Malaria plasmepsin inhibitors program.

• Speaker: Dr Manuel Ruiz, Merck
• Monday 18 November 2024, 16:00-17:00
• Venue: Dept. of Chemistry, Wolfson Lecture Theatre.
• Series: Synthetic Chemistry Research Interest Group; organiser: spring.

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In our recent work, we have made progress in understanding the complex mathematical landscape of the big bang singularity in general relativity. Utilizing Fuchsian partial differential equation techniques, we have established rigorous nonlinear stability results for certain Friedmann cosmological models, particularly focusing on solutions to the fully coupled Einstein-matter equations. This does not only reinforce some of the standard cosmological model’s assumptions in certain scenarios but also brings to light new critical phenomena that have yet to be fully understood. This research was conducted in collaboration with Todd Oliynyk from Monash University.

• Speaker: Florian Beyer, Department of Mathematics & Statistics, University of Otago
• Friday 09 February 2024, 13:00-14:00
• Venue: Potter room/Zoom.
• Series: DAMTP Friday GR Seminar; organiser: Xi Tong.

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Abstract not available

• Speaker: Prof. Peter Skands (Monash University)
• Wednesday 28 February 2024, 14:00-15:00
• Venue: Ryle Seminar Room.
• Series: Cavendish HEP Seminars; organiser: Dr Bill Balunas.

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A new computational task has been defined and solved over the past 15 years for extended material systems: the analytic fitting of the Born-Oppenheimer potential energy surface as a function of nuclear coordinates under the assumption of medium-range interactions, 5 ~ 10 Å. The resulting potentials are reactive, many-body, with evaluation costs that are on the order of 0.1-10 ms/atom/cpucore (or about 1ms on a GPU for system sizes that fit into memory), and reach accuracies of a few meV/atom when trained specifically for a given system using iterative/active learning methods. Perhaps the most surprising aspect has been the stability of models trained on very diverse training sets across the periodic table. I will show the recently published MACE -MP-0 model that was trained on just 150,000 real and hypothetical inorganic crystals (90% of training set < 70 atoms), but is capable of stable molecular dynamics on any system tested so far without any extra data – including crystals, liquids, surfaces, clusters, molecules, and combinations of all of these.

• Speaker: Professor Gábor Csanyi, University of Cambridge
• Wednesday 14 February 2024, 14:30-15:30
• Venue: Unilever Lecture Theatre, Yusuf Hamied Department of Chemistry.
• Series: Theory - Chemistry Research Interest Group; organiser: Lisa Masters.

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Clouds in marine and polar atmospheres play a pivotal role in shaping climate dynamics through intricate cloud-radiation interactions. Of particular significance are secondary aerosols, stemming from gas precursors, which act as potential nuclei for cloud droplets, exerting influence on cloud reflectivity and lifespan. This, in turn, has indirect impacts on climate. Despite their critical impact, the formation processes of marine and polar aerosols remain insufficiently explored due to experimental and logistical challenges. This presentation will present evidence drawn from field observations and laboratory experiments, underscoring the importance of iodine and sulfur species as key aerosol sources in polar and marine atmospheres. Our field observations expose the presence of HIO3 in diverse environments, including polar regions, boreal forests, marine sites, and urban areas. By combining global observations and laboratory experiments, we reveal the potential widespread involvement of iodic acid and iodous acid in marine secondary aerosol formation, challenging the traditional association of iodine aerosols solely with mid-latitudinal regions. To comprehensively grasp the worldwide implications of iodine and sulfur aerosol formation processes, a systematic analysis integrating ambient observations, laboratory experiments, and global simulations is deemed imperative.

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CAS UnionRoad is inviting you to a scheduled Zoom meeting.

Topic: CAS seminar: Dr Xu-Cheng He Time: Mar 12, 2024 11:00 AM London

Join Zoom Meeting https://us02web.zoom.us/j/82347604021?pwd=OTBaU1M5dXRUU0lnQlhtN1hmRkR4dz09

Meeting ID: 823 4760 4021 Passcode: 916884

• Speaker: Xu-Cheng He - University of Helsinki/University of Cambridge
• Tuesday 12 March 2024, 11:00-12:00
• Venue: Chemistry Dept, Unilever Lecture Theatre and Zoom.
• Series: Centre for Atmospheric Science seminars, Chemistry Dept.; organiser: Vichawan (Print) Sakulsupich.

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During December 2021, a heavy rainfall/flooding event (HRF) occurred over Peninsular Malaysia, which causes unprecedented volumes of rainfall on the West and East coast of Peninsular Malaysia (i.e. Pahang and Selangor) with significant socio-economical and financial losses. Two disturbances have been found to play key roles in this HRF event, which are cold surge vortex and Typhoon Rai. Firstly, a low-level north-easterly cold surge interacts with an easterly surge over the southern South China Sea, causing the vortex to form over East Malaysia. The vortex was then enhanced and transported towards Peninsular Malaysia by a strong easterly wind from the outer wind of Typhoon Rai over the Philippines. It further passed through the Titiwangsa mountain range over the middle of Peninsular Malaysia, resulting in an intense rainfall along the west coast. Moreover, biomass burning aerosols were suspected to be able to intensify the precipitation. Thus, the impact of biomass burning on the extreme event was carried out by using WRF -Chem numerical simulation modelling. By comparing the precipitation temporal and spatial distribution of two model scenarios (model simulations with and without biomass burning inventory), biomass burning aerosols reflect only a minor impact on intensifying or delaying the rainfall event. The extreme rainfall event was mainly caused by the cold surge induced disturbance and Typhoon Rai.

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Topic: CAS Seminar: Prof Andy Chan

Time: Feb 27, 2024 11:00 AM London

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https://us02web.zoom.us/j/89826306833?pwd=cnNHSG9OWHRjVngzMGVMc2F0NnA4dz09

Meeting ID: 898 2630 6833

Passcode: 662640

• Speaker: Andy Chan - Dean of Engineering, Robert Gordon University
• Tuesday 27 February 2024, 11:00-12:00
• Venue: Chemistry Dept, Unilever Lecture Theatre and Zoom.
• Series: Centre for Atmospheric Science seminars, Chemistry Dept.; organiser: Vichawan (Print) Sakulsupich.

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The Meteorological Synthesizing Centre West of the European Monitoring and Evaluation Programme (EMEP MSC -W, www.emep.int) has provided chemical transport modelling support to the UNECE Air Convention (unece.org/environmental-policy-1/air) since 1979. Over the years the modelling tools have developed from simple Lagrangian codes with horizontal resolution of ca. 150 km to 3-D Eulerian codes with scales ranging from ca. 1~km over limited areas to ca. 50 km for global scale calculations. The original focus on sulphur and acid deposition to ecosytems has developed into a strong focus on particulate matter (PM), and health metrics, with a massive increase in complexity. An offline extension of the EMEP model for urban areas (uEMEP) allows for estimates of some compounds to be made with resolutions of less than 100 m across Europe.

This talk will give a brief overview of the development of the EMEP models over the years, and illustrate some of the successes and issues associated with the current EMEP model, and with PM modelling in particular.

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Topic: CAS Seminar: Dr David Simpson

Time: Feb 13, 2024 11:00 AM London

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https://us02web.zoom.us/j/81502715562?pwd=WFRnV2RtMlRxQzlPbUFvQUY4WjVYZz09

Meeting ID: 815 0271 5562

Passcode: 972731

• Speaker: David Simpson - EMEP MSC-W, Norwegian Meteorological Institute
• Tuesday 13 February 2024, 11:00-12:00
• Venue: Chemistry Dept, Unilever Lecture Theatre and Zoom.
• Series: Centre for Atmospheric Science seminars, Chemistry Dept.; organiser: Vichawan (Print) Sakulsupich.

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A cubic hypersurface in projective n-space defined over the rationals is given by the vanishing locus of an integral cubic form in n+1 variables. For n at least 3, it is conjectured that the only obstruction to rational points on cubic hypersurfaces are local ones—- that is, they satisfy the local-global principle. Recent work of Browning, Le Boudec, and Sawin shows that this conjecture holds on average for n at least 4, in the sense that the density of soluble cubic forms is equal to that of the everywhere locally soluble ones. But what do these densities actually look like? We give exact formulae in terms of the probability that a cubic hypersurface has p-adic points for each prime p. These local densities are explicit rational functions uniform in p, recovering a result of Bhargava, Cremona, and Fisher in the n=2 case, as well as the fact that all cubic forms are everywhere locally soluble when n is at least 9. Consequently, we compute numerical values (to high precision) for natural density of cubic forms with a rational point for n at least 4. This is joint work with Lea Beneish.

• Speaker: Christopher Keyes (King's College London)
• Tuesday 20 February 2024, 14:30-15:30
• Venue: MR13.
• Series: Number Theory Seminar; organiser: Jef Laga.

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This talk presents some recent progress on the analysis of models coupling large-strain, geometrically nonlinear elasto-plasticity with the movement of dislocations. In particular, a new approach, building on tools from Geometric Measure Theory, is introduced that yields a natural mathematical framework for dislocation evolutions. The fundamental notion is the two-dimensional “slip trajectory” in space-time (realized as an integral 2-current) and the dislocations at a given time are recovered via slicing. This modelling approach allows one to prove the existence of solutions to an evolutionary system describing a crystal undergoing large-strain elasto-plastic deformations, where the plastic part of the deformation is driven directly by the movement of dislocations. This is joint work with P. Bonicatto (Trento), G. Del Nin (MPI Leipzig), T. Hudson (Warwick).

• Speaker: Filip Rindler, University of Warwick
• Monday 19 February 2024, 14:00-15:00
• Venue: MR13.
• Series: Partial Differential Equations seminar; organiser: Amelie Justine Loher.

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The twin prime conjecture asserts that there are infinitely many primes p for which p+2 is also prime. This conjecture appears far out of reach of current mathematical techniques. However, in 2013 Zhang achieved a breakthrough, showing that there exists some positive integer h for which p and p+h are both prime infinitely often. Equidistribution estimates for primes in arithmetic progressions to smooth moduli were a key ingredient of his work. In this talk, I will sketch what role these estimates play in proofs of bounded gaps between primes. I will also show how a refinement of the q-van der Corput method can be used to improve on equidistribution estimates of the Polymath project for primes in APs to smooth moduli.

• Speaker: Julia Stadlmann (Oxford)
• Tuesday 13 February 2024, 14:30-15:30
• Venue: MR13.
• Series: Number Theory Seminar; organiser: Jef Laga.

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New herbicides are required to improve levels or spectrum of activity, to overcome resistance to existing products, or to replace older products under regulatory pressure. The first part of the talk will describe the discovery and optimization program for dioxopyritrione (Figure 1), a novel inhibitor of 4-hydroxyphenylpyruvate dioxygenase (HPPD) for use in wheat and barley. Once a development candidate is identified, a major issue is finding a safe, scalable, and cost-efficient synthesis. For the synthesis of herbicides, cost pressure is high and thus a major effort was required to reduce the cost of manufacturing. The second part of this talk will describe process research and development activities starting from the initial route scouting and ending with the scale-up in a pilot plant, including a large-scale photochemical step.

• Speaker: Syngenta
• Thursday 29 February 2024, 16:00-17:00
• Venue: Dept. of Chemistry, Wolfson Lecture Theatre.
• Series: Synthetic Chemistry Research Interest Group; organiser: Chung Tu.

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