20 Years of MIN Faculty - Symposium

Friday 10 Oct 2025, 09:00 → 19:00 Europe/Berlin

Kai Jensen, Maria Latos

Symposium: 20 Years of MIN Faculty 

We are delighted to invite you to the MIN Faculty 20-Year Anniversary Symposium, a special event marking two decades of groundbreaking research, academic excellence, and interdisciplinary collaboration at the Faculty of Mathematics, Informatics and Natural Sciences (MIN) at the University of Hamburg.

This symposium is a central part of our anniversary celebration and brings together researchers and partners to  explore future challenges and opportunities across the MIN disciplines.

Structured around three core thematic areas — MIN Life Science, MIN Materials, and MIN Quantum Science and Technologies — the symposium offers a platform to share ideas, showcase research, and strengthen connections between diverse scientific fields.

Our goal is to promote dialogue and collaboration across disciplines, foster new partnerships, and inspire innovative approaches. Whether you are an early-career researcher, an established academic, your perspective is valuable in shaping the future of the MIN Faculty.

We warmly invite you to take part in this exciting event, contribute to the exchange of knowledge, and celebrate 20 years of shared curiosity, creativity, and discovery.

Conference Chairs

MIN Life Science: Tobias Lenz, Arne Weiberg (Biology); Zoya Ignatova (Chemistry); William Foster (Earth System Sciences); Wolfgang Parak (Physics)

MIN Materials: Linnea Hesse (Biology); Lisa Vondung, Nadja-Carola Bigall (Chemistry);  Dorota Koziej, Ralf Riedinger (Physics); Winnifried Wollner (Mathematics)

MIN Quantum Science and Technologies: Tim Wehling (Physics), Tobias Dyckerhoff (Mathematics); Sören Laue (Informatics); Dieter Jaksch (Physics)

Conference Office

Maria Latos 
Office of the Dean
Communication & Cooperations
Mail: kommunikation.min@uni-hamburg.de
Phone: +49 40 42838 8109

Site map.pdf

Plenary Session: Welcome and introduction - DESY Auditorium (Building 5)

1 MIN-Life Sciences: Understanding biological systems and adressing global challenges

• The core of Life Sciences: Understanding complex biological systems
• The bridges of life sciences to global challenges: climate, health, food, materials

Speaker: Kai Jensen

2 Introduction MIN Materials of the Future

TBC

Speakers: Dorota Koziej (University of Hamburg), Linnea Hesse (Universität Hamburg)

3 Introduction MIN Quantum Science and Technologies

TBC

10:00 Coffee Break - CSSB, CFEL, ZOQ

Life Sciences: Session Block 1, CSSB Building 15 (Click here for detailed programme)

Chair: Baris Tursun

4 Translational Lens of Gene Expression

tbc

Speaker: Zoya Ignatova

5 Hamburg School of Food Science – Food and Material Profiling

TBC

Speaker: Markus Fischer (Department of Chemistry, University of Hamburg)

6 Permafrost-Affected Ecosystems Alter the Carbon-Climate Feedback

TBC

Speaker: Christian Beer (Universität Hamburg)

7 The Journey of Small RNAs: Systemic and Interorganismal Signalling in Plants

Small RNAs (sRNAs), including microRNAs (miRNAs) and small interfering RNAs (siRNAs), play central roles in regulating gene expression in plants. Beyond their local activity, many sRNAs are mobile, moving between cells and over long distances to coordinate developmental programs and environmental responses, establishing them as systemic signalling molecules. Recent research has also established sRNAs as important interorganismal information transmitters, mediating the interaction between plants and pathogenic or beneficial microbes.
It is a matter of debate how selective and regulated the process of sRNA transport is. It is also not well understood how sRNA transport functions. There is good evidence that RNA-binding proteins (RBPs) facilitate mobility while also stabilizing sRNAs. Stability during transport is further supported by their association with Argonaute proteins, biomolecular condensates, or membrane-surrounded extracellular vesicles.
Understanding sRNA transport has broad implications for both basic biology and agricultural biotechnology. By harnessing mobile sRNAs, it may be possible to design strategies for crop protection, nutrient management, and stress resilience. Our interdisciplinary research aims to uncover principles of sRNA selectivity, stability, targeting, and functional outcomes combining state-of-the-art molecular, biochemical, biophysical, and computational methods.

Speaker: Julia Kehr (Universität Hamburg)

8 Mass Extinctions and Climate Change

TBC

Speaker: William Foster (Universität Hamburg)

9 TBC

Speaker: Arwen Pearson (Universität Hamburg)

10 Toward machine learning driven virtual cells

TBC

Speaker: Fabian Kern (Zentrum für Bioinformatik, University of Hamburg)

MIN Materials: Session Block 1, CFEL Building 99 (Click here for detailed programme)

Chairs Session I: Linnea Hesse & Dorota Koziej
Chairs Session II: Nadja Bigall & Winnifried Wollner

11 The Centre for Ultrafast Imaging (CUI)

The Centre for Ultrafast Imaging (CUI) operates the DFG Cluster of Excellence “Advanced Imaging of Matter”, consisting of partners from UHH, DESY, the Max Planck Institute for Structural Dynamics, and the European XFEL. Together, we aim to understand and manipulate the processes that arise from arrangements of atoms and molecules in different forms of matter. We image quantum processes in atoms, molecules, and condensed matter at the ultimate length and time scales, to investigate ways to control these processes. This allows us to create matter with new functionalities, such as novel quantum materials and designer proteins. We benefit from Hamburg’s exceptional infrastructure, including our suite of light sources, and strong expertise in theoretical and experimental science that spans quantum technologies, ultrafast X-ray science, condensed matter, nanoscience, and macromolecular imaging.

Speaker: Hanry Chapman (Department of Physics, University of Hamburg)

12 Future Materials for Quantum Technology

Quantum technology holds great promise for information processing, communication and sensing. However, quantum states incredibly are fragile, quickly losing their advantages properties under most circumstances. To get the technology out of the lab, into the real world, extraordinary materials are required, which exhibit robust quantum states - a challenging task, but not impossible: Join me on a walk through the past, present and future UHH-Materials that enable this new technology, and explore the colorful world of artificial crystals capturing quantum light, sound and time.

Speaker: Ralf Riedinger (Department of Physics, University of Hamburg)

13 Observation of Higgs Modes in Superconductors by Non-Equilibrium Anti-Stokes Raman Scattering

Spontaneous symmetry breaking in the Mexican-Hat potential leads to massless phase modes as low-energy excitations. In superconductors, however, coupling between the charged condensate and the gauge field shifts the phase mode to higher energies,[1] leaving the Higgs mode as the dominant low-energy excitation. The Meissner effect reflects a macroscopic quantum condensate where photons gain mass - an analogy to high-energy physics.[2] The Higgs mode was first observed in superconductors by Sooryakumar and Klein via Raman scattering in 1980, and confirmed in 2014.[3,4] Due to weak light coupling, it remained elusive except in NbSe2, where it couples to a charge density wave (CDW). Over the past two decades, experimental evidence has steadily grown. Notably, Budelmann et al. (2005) and Saichu et al. (2009) observed distinct in-gap features suggestive of collective excitations,[5,6] with later THz studies reinforcing the case for the Higgs mode.[7]
After introducing activities in our Raman lab at CFEL, this talk presents Higgs-mode observations in Bi-2212 using Non-Equilibrium Anti-Stokes Raman Scattering (NEARS).[8] We use a Tsunami Ti:Sapphire laser (1.2 ps, 80 MHz, 802 nm) and a 402 nm probe from SHG for the UT-3 spectrometer.[9] NEARS exploits a soft quench of the Mexican-Hat potential to selectively populate Higgs modes of different symmetries,[10] then probes them via anti-Stokes Raman scattering. This leads to a tunable population inversion, characterized by comparing Stokes and anti-Stokes signals. An emergent in-gap anti-Stokes peak (25 meV) grows with fluence, indicating Higgs mode population, while the Stokes side shows suppressed pair-breaking at approx. 60 meV, confirming the superconducting state 3 ps post-pump.
Our results, interpreted via Ginzburg-Landau theory and a BCS weak-coupling model, link Higgs mode energy to Cooper-pair coherence length. Phonon-subtracted susceptibilities match well with microscopic theory, notably avoiding the A1g problem at 3.1 eV photon energy.[11] NEARS thus emerges as a powerful tool for Higgs spectroscopy in quantum condensates, with broad implications for superconductivity research, including light-induced, interface, and topological effects.

References
[1] Anderson, P., Phys. Rev. 110, 827 – 835 (1958).
[2] Varma, C. M., Journal of Low Temperature Physics 126, 901 – 909 280 (2002).
[3] Sooryakumar, R. & Klein, M. V., Phys. Rev. Lett. 45, 660– 662 (1980).
[4] Littlewood, P. & Varma, C., Phys. Rev. B 26, 4883– 4893 (1982).
[5] Budelmann, D. et al., Phys. Rev. Lett. 95, 057003 (2005).
[6] Saichu, R. P. et al., Phys. Rev. Lett. 102, 177004 (2009).
[7] Shimano, R. & Tsuji, N., Annu. Rev. Condens. Matter Phys. 11, 103– 124 (2020).
[8] T.E. Glier et al, Nature Communications, Nat Commun 16, 7027 (2025).
[9] Schulz, B. et al., Rev. Sci. Instrum. 76, 073107 (2005).
[10] Schwarz, L. et al., Nat Commun 11, 287 (2020).
[11] Devereaux, T. P. & Einzel, Phys. Rev. B 51, 16336 – 16357 (1995).

Speaker: Tomke Glier (Universität Hamburg)

14 Whispers in the WAVEs: Decoding Campus Vibrations with Distributed Acoustic Sensing

The WAVE initiative at Hamburg’s Science City Bahrenfeld brings together physicists, geophysicists, and engineers from the University of Hamburg, Helmut-Schmidt University, DESY and EuXFEL.
We have developed a dense seismic sensor network by using fiber-optic sensing technology to tap into telecommunication fiber. With this, we record both anthropogenic and natural vibrations and study their coupling into large-scale, high-precision research infrastructures limited by such disturbances.

Our applications range from fundamental physics, including gravitational wave detection, to monitoring changes in the urban subsurface driven by hydrological and thermal dynamics.

I will highlight how WAVE connects to materials. First, how we can help improve the precision of EuXFEL by monitoring vibrations and deformations in accelerator structures. And second, how we can advance Structural Health Monitoring (SHM) by embedding fiber-optic sensors in building materials and structures to detect subtle changes indicating damage or material fatigue.

Speaker: Celine Hadziioannou (University of Hamburg)

15 CHyN Cleanroom - a platform for interdisciplinary micro and nano fabrication

The CRR cleanroom at the bahrenfeld Campus, managed jointly by UHH, DESY and MPI, is a versatile platform, where users can access a variety of rooms for patterning at the micro and nanoscale. These include laser, optical and electron-beam lithography, thin film deposition, dry and wet etching,etc. The platform is used by groups in different research fields, such as the development of new materials, energy harvesting, bio-nano-physics, optics or quantum physics.

Speaker: Irene Fernandez-Cuesta (UHH)

16 Mathematical Optimization for Material Science

In this talk we will highlight some recent research highlights in
mathematical optimization with applications to material science.
Topics range from free material optimization for the design of
optimal macroscopic material properties to shape optimization
approaches for the microscale design of meta materials with desired macroscopic properties.

Speaker: Winnifried Wollner (Universität Hamburg)

Quantum Science & Technologies: Session Block 1, ZOQ, Building 90 (Click here for detailed programme)

17 RYMAX & Quantum Computation

TBC

Speaker: Klaus Sengstock (Universität Hamburg, Germany)

18 The Quantum universe: Connecting particle physics, dark matter and gravitational waves

TBC

Speaker: Geraldine Servant (Department of Physics, University of Hamburg)

19 Quantum material emulation via atom-by-atom assembly

With the tip of a scanning tunnel microscope as a tool, atoms can be assembled into one (1D)- or two-dimensional (2D) lattices on solid material surfaces (1,2). Simultaneously their spin-resolved spectral functions can be measured one atom at a time (3,4). Combining spin-carrying transition metal or rare earth atomic lattices with different substrates such as normal metals (2,4-7), semiconductors (8), or superconductors (9), the hybrid systems emulate a vast variety of quantum materials. Their parameters can be widely tuned by the choice of lattice and atom species, the substrates' material and surface orientation, and the resulting topology. Thereby, these systems can be directly compared to and used for the optimization of simulation methods ranging from DMRG (10) over NRG (11), and tight binding models (12-15), to ab-initio based advanced many-body theories (6,8,11) and KKR methods (2,7,16,17) solving the Kohn-Sham-Dirac-BdG equations (18). I will review our research on such artificial spin arrays conducted in the scanning probe methods group of the MIN faculty over the past 20 years (3) involving our fruitful collaborations with different theory groups. We started with quasiclassical spin Hamiltonians along with isotropic (Heisenberg) (2), Dzyaloshinskii-Moriya (10), and symmetric anisotropic (17) RKKY-type exchange contributions to demonstrate proof-of-principle realizations of spintronic devices (5,8,16,17). More recently, we have utilized superconducting substrates to exploit competing Kondo and Cooper pairing interactions (9,11). Thereby, we have realized p-wave pairing correlations in 1D manganese chains coupled to elemental niobium (12) aiming at the emulation of the Kitaev chain Hamiltonian and the predicted Majorana edge modes (13,18). Finally, we implemented minimal-invasive non-local detection schemes for such fragile quantum states (14,15). I will finish with a prospect of future research directions towards spatially-, spin- and time-resolved spectroscopy and van der Waals materials.
Latest work was supported by the Cluster of Excellence 'Advanced Imaging of Matter' (EXC 2056 - project ID 390715994) of the Deutsche Forschungsgemeinschaft (DFG) and by the DFG - project WI 3097/4-1 (project No. 543483081).
(1) D.-J. Choi , N. Lorente, JW, K. von Bergmann, A. F. Otte, and A. J. Heinrich, Rev. Mod. Phys. 91, 041001 (2019).
https://doi.org/10.1103/RevModPhys.91.041001
(2) A. Khajetoorians, JW, B. Chilian, S. Lounis, S. Blügel, and R. Wiesendanger, Nat. Phys. 8, 497 (2012).
https://www.nature.com/articles/nphys2299
(3) JW, A. Wachowiak, F. Meier, D. Haude, T. Foster, M. Morgenstern, and R. Wiesendanger, Rev. Sci. Instrum. 75, 4871 (2004).
https://pubs.aip.org/aip/rsi/article/75/11/4871/351594/A-300-mK-ultra-high-vacuum-scanning-tunneling
(4) F. Meier, L. Zhou, JW, and R. Wiesendanger, Science 320, 82 (2008).
https://www.science.org/doi/10.1126/science.1154415
(5) A. Khajetoorians, JW, B. Chilian, and R. Wiesendanger, Science 332, 1062 (2011).
https://www.science.org/doi/10.1126/science.1201725
(6) A. Khajetoorians, M. Valentyuk, M. Steinbrecher, T. Schlenk, A. Shick, J. Kolorenc, A. I. Lichtenstein, T. O. Wehling, R. Wiesendanger, and JW, Nat. Nanotechnol. 10, 958 (2015).
https://www.nature.com/articles/nnano.2015.193
(7) M. Steinbrecher, A. Sonntag, M. dos Santos Dias, M. Bouhassoune, S. Lounis, JW, R. Wiesendanger, and A. Khajetoorians, Nat. Commun. 7, 10454 (2016).
https://www.nature.com/articles/ncomms10454
(8) A. Khajetoorians, B. Chilian, JW, S. Schuwalow, F. Lechermann, and R. Wiesendanger, Nature 467, 1084 (2010).
https://www.nature.com/articles/nature09519
(9) R. Lo Conte, JW, S. Rachel, D. Morr, and R. Wiesendanger, Riv. Nuovo Cim. 47, 453 (2025).
https://doi.org/10.1007/s40766-024-00060-1
(10) M. Steinbrecher, R. Rausch, K. T. That, J. Hermenau, A. Khajetoorians, M. Potthoff, R. Wiesendanger, and JW, Nat. Commun. 9, 2853 (2018).
https://www.nature.com/articles/s41467-018-05364-5
(11) A. Kamlapure, L. Cornils, R. Žitko, M. Valentyuk, R. Mozara, S. Pradhan, J. Fransson, A. I. Lichtenstein, JW, and R. Wiesendanger, Nano Lett. 21, 16 (2021).
https://pubs.acs.org/doi/full/10.1021/acs.nanolett.1c00387
(12) L. Schneider, P. Beck, T. Posske, D. Crawford, E. Mascot, S. Rachel, R. Wiesendanger, and JW, Nat. Phys. 17, 943 (2021).
https://www.nature.com/articles/s41567-021-01234-y
(13) L. Schneider, P. Beck, J. Neuhaus-Steinmetz, L. Rózsa, T. Posske, JW, and R. Wiesendanger, Nat. Nanotechnol. 17, 384 (2022).
https://www.nature.com/articles/s41565-022-01078-4
(14) L. Schneider, K. That Ton, I. Ioannidis, J. Neuhaus-Steinmetz, T. Posske, R. Wiesendanger, and JW, Nature 621, 60 (2023).
https://doi.org/10.1038/s41586-023-06312-0
(15) K. Ton That, C. Xu, I. Ioannidis, L. Schneider, T. Posske, R. Wiesendanger, D. K. Morr, and JW, arXiv:2410.16054 [cond-mat.supr-con].
https://doi.org/10.48550/arXiv.2410.16054
(16) J. Hermenau, J. Ibañez-Azpiroz, Chr. Hübner, A. Sonntag, B. Baxevanis, K. T. Ton, M. Steinbrecher, A. Khajetoorians, M. dos Santos Dias, S. Blügel, R. Wiesendanger, S. Lounis, and JW, Nat. Commun. 8, 642 (2017).
https://www.nature.com/articles/s41467-017-00506-7
(17) J. Hermenau, S. Brinker, M. Marciani, M. Steinbrecher, M. dos Santos Dias, R. Wiesendanger, S. Lounis, and JW, Nat. Commun. 10, 2565 (2019).
https://www.nature.com/articles/s41467-019-10516-2
(18) B. Nyári, P. Beck, A. Lászlóffy, L. Schneider, K. Palotás, L. Szunyogh, JW, B. Újfalussy, and L. Rózsa, Phys. Rev. B Accepted (2025).
https://journals.aps.org/prb/accepted/3e07cK88Qf81e70ed9ad2065e47f5e09476d83482

Speaker: Jens Wiebe (Universität Hamburg)

20 Ultrafast manipulation of quantum matter

TBC

Speaker: Francesca Calegari (Department of Physics, University of Hamburg)

21 Quantum simulation with ultracold atoms

TBC

Speaker: Peter Schauss (University of Virginia)

22 Superconducting microwave cavities for high frequency gravitational wave searches

High frequency gravitational waves could carry unique information about the early universe and physics beyond the standard model. However, measuring these elusive signals requires dramatic technology, such as superconducting microwave cavities, which are highly efficient resonators. I will introduce a gravitational wave detector based on such a cavity and explain how it could evade standard quantum limits to reach the necessary sensitivities in the future.

Speaker: Tom Krokotsch (Department of Physics, University of Hamburg)

23 Bolometer in the search for axions

TBC

Speaker: Monireh Yamrali (Department of Physics, University of Hamburg)

24 Development of quantum noise limited displacement sensors for next generation gravitational wave detectors

Current ground-based gravitational wave observatories are limited by controls induced displacement noise at low frequencies (below 30Hz). To increase the sensitivity of current observatories and reach the desired performance of the next generation we are developing new compact and ultra precise interferometric displacement sensors, which are limited by quantum noise and make use of novel machine learning readout algorithms.

Speaker: Leander Weickhardt (Department of Physics, University of Hamburg)

12:00 Lunch Break - DESY Foyer (Building 5)

Poster Presentation - DESY Foyer (Building 5): Poster Session 1

25 **Metal Nanoparticle-Based Strategy for Enhanced Contrast in XRF Imaging**

X-ray fluorescence (XRF) imaging is a powerful technique for mapping elemental distributions, particularly metals, in biological tissues [1]. However, its broader application is constrained by the scarcity of effective contrast agents. To address this limitation, we developed a novel strategy that uses an approach to trigger site-specific growth of metal nanoparticles (NPs) in situ, enhancing spatial resolution in biological XRF imaging [2].
This synthesis strategy achieves three key advances:
(1) Biomarker-specific signal localization; (2) Significantly enhanced image contrast; (3) Compatibility with complex cellular architectures.
By employing this strategy, we anticipate notable improvements in image contrast and specificity, which may substantially broaden the utility of XRF imaging in biomedical research.

Central to our method is the use of catalytic or bio-orthogonal reactions to selectively deposit nanoparticles at molecular targets of interest. This enables highly sensitive detection of low-abundance biomarkers through amplified XRF signals. Furthermore, the modular design of the precursor probes allows for adaptation to various biological contexts, ranging from fixed tissue sections to live cell imaging. We will demonstrate the efficacy of this approach in model systems including mammalian cells and murine cancer tissues, showcasing its potential for applications in neurobiology, metallomics, and diagnostic pathology.

Speaker: Wenbo Wang (Universität Hamburg)

26 Bacteria–Tumor Spheroid Co-Culture Model Labeled with Multi-Metal Nanoparticles and Its X-ray Fluorescence Imaging Study

Abstract
Recent studies have revealed the presence of diverse bacteria within solid tumors of cancer patients. The intrinsic tumor-targeting properties of these bacteria, along with the selective colonization observed in animal models, have renewed interest in employing bacteria as carriers for cancer therapy. However, due to the limitations of current in vivo imaging technologies, the spatiotemporal distribution of bacteria within tumors remains difficult to capture accurately, hindering systematic studies of their mechanisms of action and safety. Meanwhile, metal nanoparticles (NPs), owing to their tunable properties and multifunctionality, have demonstrated great potential in integrated tumor diagnosis and therapy. Three-dimensional tumor spheroids, as in vitro models of solid tumors, provide a reliable platform to study NP delivery, diffusion, and intercellular interactions.
In this study, we established a bacteria–tumor spheroid co-culture system labeled with multiple NPs. In situ labeling was achieved via bacterial intracellular reduction. Lactobacillus has been verified to generate gold nanoparticles (AuNPs), and we further attempted the synthesis of self-fluorescent selenium nanoparticles (SeNPs) for early-stage imaging and tracking bacterial dispersion. Simultaneously, Ni, Bi, Fe, and Au NPs were used to label different tumor cell lines, establishing both homogeneously mixed and core–shell structured 3D tumor spheroid models. Using multi-element synchronous detection and high-resolution visualization through X-ray fluorescence imaging (XFI), this system enables non-destructive imaging of multi-metal labels, allowing systematic investigation of interactions between bacteria and tumor cells.

Progress
In our preliminary studies, we successfully synthesized AuNPs using Lactobacillus and conducted initial in vivo reduction experiments for SeNPs to track bacterial dispersion. Additionally, we prepared and functionalized Ni, Bi, Fe, and Au nanoparticles with controlled sizes and efficient cellular uptake, and constructed multi-layered tumor spheroid models based on 4T1, MCF-7, and HeLa cell lines. XFI experiments were performed at the P06 beamline of the DESY synchrotron in Germany. Clear and stable imaging signals were obtained in 2D cell layers, and partial 3D tumor spheroid samples were successfully imaged, preliminarily demonstrating their feasibility as XFI targets and providing a good signal-to-noise ratio.

Innovation and Significance
The novelty of this study lies in the first integration of bacterial intracellular reduction and cellular uptake pathways to achieve a systemically designed multi-metal labeling strategy. A multi-scale “fluorescence–XFI” imaging approach was employed to achieve multi-level visualization of bacteria and tumor spheroids. This platform not only overcomes the limitations of current in vivo imaging in terms of resolution and multi-element detection but also offers a high-throughput, accessible approach to study the dynamic behavior of bacteria in the tumor microenvironment and explore tumor–microbiota interaction mechanisms. The system holds significant value for fundamental research and potential clinical translation.

Speaker: Shihao Zhou (Universität Hamburg)

27 Category-theoretic properties of Haskell monads

A major characteristic of functional programming languages is that the computation is free of side
effects, meaning that given the same input a function will always produce the same result. If we want
to use side effects like output, computation that may fail or access to ‘states’ of the program, we need
extra tools to simulate these.
In the functional programming language Haskell the simulation of side effects can be realized using
‘monads’. Since the term ‘monad’ also refers to a fundamental concept in category theory, the
question arises how these topics are related.
In order to study this relation, we will argue a suitable categorical model for Haskell which we will use
to discuss the categorical properties of Haskell functors, monads and monad transformers.
Furthermore, we will present one of the most common monads (and also monad transformers) in
Haskell and give an example for the benefits of applying mathematical theorems to Haskell monads.

Speaker: Marie Feddersen (Universität Hamburg)

28 CMT-aaRS variants cause translational defect alleviated by cognate tRNA enhancement

Dominant missense mutations in eight aminoacyl-tRNA synthetases (aaRSs) are associated with axonal and intermediate forms of Charcot-Marie-Tooth (CMT) disease. The molecular mechanisms by which these ubiquitously expressed enzymes cause selective peripheral neuronal degeneration remain elusive. To address this, we use cell models and patient-derived materials. Employing a variety of high-resolution approaches (e.g. microscopy, NGS, AI-based, biochemical methods), we discovered a common mechanism of tRNA sequestration that alters translation and is likely linked to accelerated neuronal degeneration.

Speaker: Sven Hürländer (Department of Chemistry, University of Hamburg)

29 Developing Advanced Nanomedicines

Nanoparticles (NPs) are being actively developed for applications in disease treatment and diagnosis—for example, as carriers for mRNA, agents for photothermal therapy in prostate cancer, or as contrast agents for magnetic resonance imaging (MRI) (1). However, their clinical use remains limited. A major challenge lies in achieving targeted delivery of NPs, as well as in controlling when and where they become active, and how they are cleared from the body. These challenges are closely related to the control of their biodistribution and pharmacokinetics.
While requirements vary depending on the specific application, improved biodistribution can help reduce off-target side effects, and optimized pharmacokinetics can lower the required dosage and minimize long-term toxicity—such as by enhancing clearance mechanisms. Although many qualitative mechanisms of NP interaction with cells and tissues have been identified, detailed quantitative understanding is still lacking.
Our team focuses on developing new nanomedicines and drug delivery systems functionalized with target-specific ligands to enable tailored, precision therapies (2–3). We are also advancing nanoparticle-based probes for both in vivo and ex vivo imaging applications (4).

[1] N. Feliu, et al. Science 384, 385–386 (2024)
[2] D. Zhu, et al. Adv. Healthc. Mater. 10, 2100125 (2021)
[3] A. M. Alkilany, et al. Adv. Drug Deliv. Rev. 143, 22–36 (2019)
[4] M. Skiba, et al. Adv. Funct. Mater. 35, 2408539 (2025)

Speakers: Neus Feliu Torres (Universität Hamburg), Pascal Nakielski

30 Establishment of a Bioinformatic Pipeline to Characterize the Phase Separation of Proteins in Plant Cells

Formation of biomolecular condensates by liquid-liquid phase separation is a dynamic process that is triggered by variations in environmental conditions such as temperature, pH or ionic strength. Characterising the phase separation behaviour of individual proteins is crucial to understand the mechanism and function of condensate assembly. By using the two paralogs of the eukaryotic Elongation Factor EF1Bβ, named eEF1BBβ1 and eEF1BBβ2, of Arabidopsis thaliana that exhibit a differential temperature-dependent condensation behaviour, two different bioinformatic tools for assessing condensation behaviour in a quantitative and qualitative manner are presented: The first is a pipeline implementing the CellProfiler granularity measurement, an open-source analytical tool (Carpenter et al., 2006; McQuin et al., 2018) and the second is based on the artificial intelligence object segmentation of the Nikon NIS Elements software (RRID:SCR_014329).

Speaker: Magdalena Weingartner (Universität Hamburg)

31 Going towards green Chemistry: Iron catalysed Suzuki cross coupling

Palladium-catalyzed cross-coupling reactions are the most powerful tool in C-C bond formation reactions. Among those, the Suzuki-reaction is of particular interest, as it can be carried out under mild reaction conditions using non-toxic, inexpensive and readily available boronic acids.
The aim was to establish a reaction catalyzed by abundant iron instead of detrimental and expensive palladium. Using iron, the coupling of biaryl compounds poses a particular challenge, and for the Suzuki-type reactions there is only one example in literature.
Accordingly, our work in which an aryl chloride is made accessible by an ortho-directing imine for this type of cross coupling reaction is satisfactory. The imine function is excellently suited for post modifications, so that industrially important substances such as boscalid, DOPO and telmisartan were synthesized from the products. Besides, a deeper understanding of this reaction was gained by performing detailed kinetic analysis and stoichiometric experiments.

Speaker: Constanze von Meyenn (Department of Chemistry, University of Hamburg)

32 Introduction of the research group "Chemometrics of complex material systems"

In the research group "Chemometrics of Complex Material Systems" of Stephan Seifert at the Hamburg School of Food Science, analytical data corresponding to fingerprints of biological samples are analysed. These fingerprints come, for example, from food or written artefacts, and are classified using machine learning methods based on various properties, such as their geographical origin. The methodological focus of the group is on the development of random forest approaches, e.g. for variable selection and the analysis of underlying mechanisms, as well as on the fusion of different analytical data.

Speaker: Stephan Seifert (Hamburg School of Food Science)

33 Molecular Fingerprinting - Genomics, Proteomics and Metabolomics-based Artefact Profiling

As part of the Cluster of Excellence “Understanding Written Artefacts”, historical palm leaf manuscripts from South India (Puducherry, Tamil Nadu) are being examined, as they represent one of the world’s most significant and numerous forms of handwritten artefacts. However, their material properties have hardly been systematically studied, if at all. The aim of this research is to gain insights into their production, geographical origin, use, and preservation, thereby contributing to a deeper understanding of written artefacts across cultures.

Genomics-, proteomics-, and metabolomics-based methods are used to obtain the most comprehensive chemical information possible about the manuscripts. These non-targeted approaches aim to create high-resolution chemical profiles, which are then compared using chemometric methods. In this way, differences and similarities can be identified, allowing conclusions to be drawn about the above-mentioned research questions. In addition to the ancient manuscripts, fresh and unprocessed palm leaves from various species are also analysed, allowing the results and approaches developed to be transferred to the historical samples.

The results open up new research perspectives in philology, codicology, and palaeography, thereby improving our understanding of material and textual cultures throughout Asia.

Speaker: Dr Marina Creydt (Department of Chemistry, University of Hamburg)

34 Photocorrosion and protection of CuBi2O4 electrodes monitored by operando surface-sensitive x-ray scattering and impedance spectroscopy

The low stability of most semiconducting materials is a key challenge in the development of efficient photoelectrochemical (PEC) water splitting cells. Monitoring the semiconductor-electrolyte interface during operation is essential to understand all the underlying photocorrosion processes and, in turn, establishing appropriate mitigation strategies.
We developed a custom-built PEC cell that enables real-time assessment of the crystalline and morphological evolution of the semiconductor surface by operando grazing-incidence X-ray scattering. We applied the technique to monitor the evolution of CuBi2O4 films, a promising p-type semiconductor for the cathodic compartment of a PEC cell.
Our operando technique, combined with complementary X-ray absorption near edge spectroscopy (XANES) and inductively coupled plasma mass spectroscopy (ICP-MS) measurements, uncovers multiple degradation pathways affecting CuBi2O4 films performance during PEC operation. We found that CuBi2O4 undergoes reduction to metallic Bi and Cu, with the first one being the fastest process. Additionally, Cu ions are released in the electrolyte during long-term stability tests, while BiPO4 forms at the surface of the CuBI2O4 film, due to the presence of phosphate ions in the electrolyte. This study provides a comprehensive view of the degradation mechanisms at the CuBi2O4 electrodes surface under operation and establishes a methodological foundation for investigating the photocorrosion of a wide range of PEC materials.
Additionally, using Electrochemical Impedance Spectroscopy (EIS) under light illumination, we also monitored the charge transport properties of CuBi2O4 films protected with TiO2 via atomic layer deposition (ALD). By fitting the EIS data with an appropriate equivalent circuit model, we extracted the charge transfer resistances, capacitances, and time constants that influence the PEC performance of the electrode as a function of the TiO2 layer thickness. Our findings reveal that a band-mismatch between the two materials leads to the accumulation of photogenerated electrons at their interface, resulting in a performance decline for TiO2 thickness greater than 15 nm

Speaker: Francesco Caddeo (Universität Hamburg)

35 Synthesis and Self-Assembly of Titania Nanoplates and Their Encapsulation within a Polystyrene Shell via Photocatalytic Surface-Initiated Polymerization

Natural composite materials such as nacre have gained significant interest due to their exceptional mechanical properties, including high hardness and toughness.[1] Promising bio-inspired materials are inorganic nanoplates stabilized by a soft layer of organic ligands. These nanoplates can be self-assembled into hierarchically ordered structures, resembling the architecture of tough biocomposites, such as nacre. Here, we explore the synthesis of titania nanoplates (TNPs), their self-assembly into supraparticles via an emulsion-based bottom-up approach, and the subsequent encapsulation within a polymer shell.
Firstly, we introduce new findings regarding the synthesis of oleyl amine-stabilized TNPs using an adapted seeded-growth approach.[2] Parameters allowing the tunability of the edge length and the thickness of the TNPs will be presented. The TNPs can then be assembled into supraparticles via emulsion-induced self-assembly,[3] resulting in the formation of three-dimensional spherical supraparticles with sizes of approximately 100 – 400 nm. Subsequent encapsulation within a polymer shell is expected to enhance the mechanical properties of these supraparticles. We developed a novel photocatalytic surface-initiated radical polymerization exploiting the inherent photocatalytic activity of the TNPs. The polymer shell thickness can be tuned by varying the UV light exposure time. An interesting finding is the high degree of order of the individual TNPs within the encapsulated supraparticles, studied via synchrotron small-angle X-ray scattering. This method was also expanded to the assembly and encapsulation of supraparticles from differently shaped titania nanoparticles (rods, dots).
Further, in order to fabricate a hierarchically ordered material with multiple hierarchical levels, we intend to crosslink the supraparticles. To this end, the polystyrene shell of the TNP-based supraparticles was surface-modified using styrene-based functional monomers as a proof of concept. We expect that the encapsulated supraparticles and their higher-level assemblies provide new insights into properties of hierarchically ordered artificial nanocomposites.

[1] M. Eder et al., Science 2018, 362, 543-547.
[2] T. R. Gordon et al., J. Am. Chem. Soc. 2012, 134, 6751-6761.
[3] F. Bai et al., Angew. Chem. Int. Ed. 2007, 46, 6650-6653.

Speaker: Jana Struck (Universität Hamburg)

36 Towards the stabilization of the FAPbI3 based active layer

Towards the stabilization of the FAPbI3 based active layer
T. Stoebke1*, M. T. Duong, N. C. Bigall1,2

1Institute of Physical Chemistry, University Hamburg, Germany
2The Hamburg Centre for Ultrafast Imaging, Hamburg, Germany
*thorben.stoebke@uni-hamburg.de

In recent decades, research activity in the field of nanomaterials and nanoparticles has significantly increased, leading to a growing number of potential applications for these materials across various scientific and technological fields. One key area where this research finds immense significance is in photovoltaics, as there is a pressing need for new active materials that can facilitate more affordable energy production and meet the rapidly expanding photovoltaic energy market. Among the emerging materials, perovskites have emerged as the most promising class for current photovoltaic research. These materials have drawn considerable attention due to their potential to provide high performance, as perovskite-based solar cells have reached power conversion efficiencies comparable to those of state-of-the-art silicon cells in the laboratory environment. However, despite their impressive efficiencies, perovskite solar cells still lag behind traditional silicon-based cells in crucial aspects such as chemical and phase stability [1], [2].
One possible approach to enhancing the stability of perovskite solar cells involves the use of nanoparticles, as highlighted by Masi et al. [3]. The reason is that, due to their smaller size and the presence of ligands on their surfaces, nanoparticles can help stabilize the cubic photoactive phase of perovskite materials.
This study thus presents our ongoing research focusing on the use of formamidinium lead triiodide (FAPbI₃) perovskite nanoparticles as active materials in solar cell applications. For this purpose, different shapes of nanoparticles e.g. nanorods, nanoplatelets, and nanocubes, are being fabricated using a modified room temperature synthesis, following the approach described by Huang et al. [4]. These nanoparticles are then systematically compared with regarding their optical properties, such as absorption and emission, as well as their phase stability.

References
[1] M. A. Green, A. Ho-Baillie, ACS Energy Letters 2017, 2, 822-830.
[2] M. Hao, S. Ding, S. Gaznaghi, H. Cheng, L. Wang, ACS Energy Letters 2024, 9, 308-322.
[3] S. Masi, A. F. Gualdrón-Reyes, I. Mora-Seró, ACS Energy Letters 2020, 5, 1974-1985.
[4] H. Huang, Y. Li, Y. Tong, E.-P. Yao, M. W. Feil, A. F. Richter, M. Döblinger, A. L. Rogach, J. Feldmann, L. Polavarapu, Angew. Chem. Int. Ed. 2019, 58, 16558.

Speaker: Thorben Stoebke (Universität Hamburg)

Poster Presentation - DESY Foyer (Building 5): Poster Session 2

37 Atomic Layer Deposition of Materials at the MIN Faculty: From History to Prospects

Atomic layer deposition (ALD) relies on sequential self-limiting gas-solid surface reactions, facilitating conformal coatings with sub-nanometer precision on complex substrates while avoiding shadowing effects. ALD originated in the 1960s and 1970s; however, academic interest significantly rose approximately two decades ago with the commercial availability of the first ALD reactors for research and development in larger quantities. Shortly after the establishment of the MIN faculty in 2005, the initial ALD reactor was commissioned within the former Institute of Applied Physics in the Physics department. Since then, a dense network of collaborations has been established within physics and chemistry, as well as with external partners in the greater Hamburg area (TUHH, DESY, and Hereon).

ALD facilitates uniform and customized coatings across various dimensions, ranging from nanometer-sized pores to macroscopic superconducting radiofrequency cavities. The plethora of materials that can be deposited enables a wide variety of applications. We have utilized ALD to fabricate superconducting thin films, magnetic nanostructures, and customized semiconductors for detectors. Moreover, additional application areas in collaboration with internal and external partners have been addressed, including protective coatings for maintaining substrate biocompatibility and chemical stability, (electro-) photocatalytic applications, and photonic crystals.

This presentation will provide an overview of previous research on ALD in physics, but also chemistry, at the MIN faculty followed by a discussion of ongoing and future projects, including collaborations with IExp and DESY on the coating of SRF cavities, as well as with TUHH in the "BlueMat" Cluster of Excellence.

Speaker: Robert Zierold (Universität Hamburg)

38 Climate Change and Food – Effects of Increased CO2 Concentrations and Drought Stress on the Metabolic Profile of Soybeans

Plants are exposed to rising CO2 concentrations, which are increasing by 1.5-2.0 ppm annually in the atmosphere. At the same time, more and more plants are experiencing further challenges due to water scarcity. These changing living conditions require most organisms to make corresponding physiological adaptations.

Although science and politics have been tracking the effects of such exogenous factors for more than three decades, it is not yet clear what influence climate change will have on the composition of our food in the long term. The results of previous studies are not always clear in this regard and seem to depend heavily on the plant genera or species considered, with the results sometimes being contradictory.

In view of this diffuse data situation, soybean plants were cultivated under different CO2 and water contents in the present study. Leaves were examined at regular intervals to analyze gas exchange. In addition, the metabolic profile of the soybeans was analyzed using high-resolution mass spectrometry (LC-ESI-IM-QTOF, non-targeted metabolomics) and then evaluated by means of various multivariate evaluation strategies.

The gas exchange measurements showed that the CO2 uptake rate increases at elevated CO2 concentrations and decreases under drought stress. The transpiration rate decreases under drought stress, but does not respond to increased CO2 concentration in the atmosphere. While the drought stress conditions did not have strong effects on the metabolic profile of soybeans, numerous differences in the metabolome could be observed in the plants cultivated at different CO2 concentrations. These differences particularly affected the lipid composition of the soybeans.

Speaker: Dr Marina Creydt (Department of Chemistry, University of Hamburg)

39 Colloidal Synthesis of Ultra-Large InAs Quantum Dots

The number of applications which operate in low or even no lighting conditions is increasing rapidly. Examples are smartphone industry, automotive engineering, enhanced vision, and automated material sorting. Indium Arsenide (InAs) Semiconductor Quantum Dots (QDs) are highly promising, RoHS-compliant candidates for infrared (IR) applications, which require much lower manufacturing costs compared to the well-known material for IR-sensing, the InGaAs.[1] However, the synthesis of larger InAs QDs above ~ 13 nm[2], optically active in the IR range above ~ 1,850 nm[2], has not been reported.
Here, we present novel colloidal synthesis methods to produce high-quality (ultra-)large InAs QDs with record-breaking sizes up to ~ 40 nm. These QDs exhibit high crystallinity and show stacking behaviour, which is essential for layer-processing applications such as sensors. Using our controlled method, we can produce single, non-elongated quantum dots in a defined manner, with a tunable band gap deep in the IR, reaching values even above ~2,600 nm.

[1] M. Ackerman, J. Inf. Disp. 2020, 36(6):19-23.
[2] M. Kim et al. J. Am. Chem. Soc. 146, 2024, 10251−10256.

Speaker: Ekaterina Salikhova (Universität Hamburg)

40 Magnetic resonance imaging of slow flow in plants.

The functionality of vascular systems in complex plant regions like nodes, which connect stems with lateral organs, remains only partially understood. Spatially resolved slow-flow measurements could provide new insights into flow dynamics in and between vascular bundles and the conductive connections of lateral organs. Traditional methods lack spatial resolution and imaging flow using contrast agents is highly invasive and damaging to the tissue. Promising results in phantoms and in some cases in living plants were demonstrated using pulsed field gradient spin-echo sequences (PFGSE) in magnetic resonance imaging (MRI). However, previous phantoms using flow velocities at 17 mm/s in a 0.4 mm radius tube or 3 mm/s in a 0.35 mm radius tube, demonstrated flow conditions beyond typical plant vasculature. Xylem vessels and flow velocities in plants typically range from 10–200 µm and 1–10 mm/s respectively, depending on environmental conditions.

Our goal was to modify a standard Bruker spin-echo DTI sequence by adding a RARE-module to be able to acquire q-space and measure flow in a spatially resolved manner. For this, we used a Bruker 9.4-T AvanceNeo 400WB vertical bore NMR spectrometer equipped with a Bruker Micro2.5 imaging probe and gradient insert delivering maximally 1467.2 mT/m.

We will present measurements on phantoms, simulating sap flow in plants verifying the robustness and accuracy of our method. Furthermore, we show the first flow measurements on a naturally transpiring shoot of Passiflora quadrangularis. In previous studies, the dynamic displacement propagator for voxels with flow exhibited an asymmetric shoulder on one side of the Gaussian distribution, unlike voxels containing only stationary water. With the improved gradient strength, we can resolve propagators with distinct peaks, separated from the stationary water fraction, that are shifted depending on the flow velocity in each voxel. In addition, we demonstrate that by tailoring the parameters to the existing conditions, the measurement time can be reduced from 3 h 25 min to just 55 s, while still distinguishing between stationary and flowing water on a voxel basis.

---

Acknowledgements:
The authors thank the Core Facility AMIRCF (DFG-RIsources N° RI_00052) for support in measuring at the AvanceNeo 400 MHz WB (INST 39/1224-1). We thank the Deutsche Forschungsgemeinschaft (DFG, German ResearchFoundation) for funding (project number: 464609293). Noah Knorr is supported by the Add-on Fellowship of the Joachim Herz Foundation and the German Academic Scholarship Foundation.

Speaker: Noah Knorr (Biomimetics Group, Institute of Wood Science, Department of Biology, University of Hamburg, Germany.)

41 Optimizing Protein Corona Recovery from AuNPs for MS Quantification

Understanding protein–nanoparticle interactions is crucial for evaluating the behaviour of nanoparticles (NPs) in biological environments. While the physicochemical of NPs is determined by factors such as size, shape and surface chemistry, their biological identity is rapidly established upon exposure to biological fluids through the immediate adsorption of biomolecules such as proteins. In this work, our aim is to establish the foundation for a robust protein mass spectrometry (MS)-based quantification method to investigate the protein coronas formed on gold nanoparticles (AuNPs) of different sizes and surface coatings.
In addition, we aim to verify the successful formation of a protein corona after characterization by employing complementary analytical techniques, such as fluorescence-based tracking of labelled proteins, dynamic light scattering, and other solution-based assays. These steps allow us to validate that the adsorption of proteins has occurred prior to corona isolation.
Our approach relies on comprehensive particle system characterization, ensuring that observed changes in corona composition can be directly linked to well-defined nanoparticle properties. To monitor protein binding and recovery prior to MS analysis, we employed labelled proteins and defined test solutions as model systems for method development. A central challenge lies in designing an efficient protocol for protein corona isolation and desorption that minimizes loss while enabling recovery of the full complement of adsorbed proteins, with complete removal of NPs prior to MS. Looking ahead, the method is being tailored for compatibility with both bottom-up (peptide-based) and top-down (intact protein) MS approaches, providing a versatile framework for the quantitative and qualitative characterization of nanoparticle–protein interactions.

Speakers: Mr Jannis Jährling, Mr Noah Frantz

42 Overview of research in the Biophotonik Group

From the synthesis of nanoparticles and their assembly towards biological applications.

Speakers: Florian Schulz, Neus Feliu Torres (Universität Hamburg)

43 Photothermal Activation of Gold Nanoparticles Star-shaped Induces Calcium Release in T-lymphocytes

Calcium ions (Ca²⁺) are critical secondary messengers in T cells, governing activation, gene expression, and effector functions. Precisely manipulating intracellular Ca²⁺ levels is a powerful but challenging approach for studying immunology and developing therapies for immune-related diseases.
We utilised the unique photothermal properties of gold nanostars (AuNSs), which were internalised by Jurkat T cells. Upon irradiation with a laser tuned to the AuNSs' absorption peak, the nanoparticles converted light to heat, inducing a localised temperature increase.
This photothermal stimulus triggered a rapid and significant release of intracellular Ca²⁺. Real-time live-cell imaging using a Ca²⁺-binding fluorophore revealed a distinct fluorescence peak corresponding to the laser stimulus. Co-localisation studies indicated that the initial Ca²⁺ microdomains originated from lysosomal stores, subsequently amplifying into a global cellular signal.
We demonstrate a novel, non-invasive method for the precise spatiotemporal control of Ca²⁺ signalling in T cells using photothermal nanoparticles. This technique provides a valuable tool for probing fundamental immunology and has promising therapeutic potential for modulating immune responses in cancer, autoimmunity, and inflammation.

Speaker: Maya Luongo (Universität Hamburg)

44 Second-order superintegrable Hamiltonian systems via conformal and information geometry

Second-order maximally superintegrable Hamiltonian systems are important structures in mathematical physics. Famous examples are the Kepler-Coulomb system and the Harmonic Oscillator.
We establish a geometric framework for a large class of these systems (joint work with J. Kress and K. Schöbel). It encodes the superintegrable system in a (1,2)-tensor field.
This geometric data reflects a naturally underlying Weyl (i.e. conformal) structure. Moreover, it induces the natural structure of a statistical manifold with torsion.
To illustrate the general framework, we present a class of examples called "abundant systems". These can be realized as affine hypersurfaces (joint work with V. Cortés). In particular, on spaces of constant sectional curvature, we find a one-to-one correspondence between these superintegrable systems and (non-flat) Frobenius manifolds whose underlying Riemannian metric can be written as the second derivative of a function ("Hessian structure", partly joint with J. Armstrong).

Speaker: Dr Andreas Vollmer (Department of Mathematics, University of Hamburg)

45 Semiconductor Nanoparticle-based Gels as Photoactivated Gas Sensors

Gels based on semiconductor nanoparticles are of scientific interest for applications in electrochemical sensing or catalysis, because they offer a unique combination of nanoscopic and macroscopic properties.[1,2,3,4] This work focuses on cadmium selenide/cadmium sulfide nanorods and their application as gas sensors.
The particles where synthesized following a synthesis route published by Carbone et al.[5], which allows for a narrow size distribution of the obtained particles. After the synthesis in organic solution, a phase transfer to aqueous solution is performed. To this, hydrogen peroxide is added, which leads to a gelation of the nanoparticles and the formation of a hydrogel. Depending on the method of drying, either xerogels (ambient drying) or aerogles (supercritical drying) can be obtained.[6]
Upon excitation with light, excitons will be formed inside the gel. Due to the band structures of the nanoparticles, the electron can scatter over multiple rods inside the gel network, increasing the exciton lifetime. By applying a voltage, a photocurrent is obtained, which should change if exposed to gaseous analytes, therefore allowing these gels to be used as gas sensors.[4,7,8,]
References
[1] Liu, W., Hermann, A., Bigall, N. C., Rodriguez, P., Wen, D., Oezaslan, M., Schmidt, T. J., Gaponik, N. and Eychmüller, A., Acc. Chem. Res. 2015, 48, 154-162.
[2] Fu, G., Yan, X., Chen, Y., Xu, L., Sun, D., Lee, J. and Tang, Y., Adv. Mater. 2018, 30, 1704609.
[3] Liu, X., Sun, J. and Zhang, X., Sens. Actuators B Chem. 2015, 211, 220-226.
[4] Schlosser, A., Meyer, L. C., Lubkemann, F., Miethe, J. F. and Bigall, N. C., Phys. Chem. Chem. Phys. 2019, 18, 9002-9012.
[5] Carbone, L., Nobiel, C., De Giorgi, M., Della Sala, F., Morello, G., Poma, P., Hytch, M., Snoeck, E., Fiore, A., Franchin, I. R., Nadasan, M., Silvestre, A. F., Chiodo, L., Kudera, S., Cingolani, R., Krahne, R. and Manna, L., Nano Letters 2007, 7, 2942-2950.
[6] Rusch, P., Lübkemann, F., Borg, H., Eckert, J. G., Dorfs, D. and Nadja, N. C., J. Chem. Phys. 2022, 156, 234701.
[7] Wen, X., Sitt, A., Yu, P., Toh Y. R. and Tang, J., Phys. Chem. Chem. Phys. 2012, 14, 3505-3512.
[8] Miethe, J. F., Luebkemann, F., Schlosser, A., Dorfs, D., and Bigall, N. C., Langmuir 2020, 36, 4757- 4765.
Acknowledgements. This work is funded by the Cluster of Excellence 'CUI: Advanced Imaging of Matter' of the Deutsche Forschungsgemeinschaft (DFG) - EXC 2056 - project ID 390715994.

Speaker: Jan Niklas Beyer (Universität Hamburg)

46 Synthesis of Size and Surface Dependent Gold Nanoparticles for Future Bioaccumulation Studies

Nanoparticles (NPs) have become a hot topic in the development of new, highly sensitive diagnostic methods, especially regarding targeted applications. Shape and size are defined by the properties of the inorganic core and the polymer-shell is of utmost importance for the functionality. This study aims the synthesis and surface functionalisation of Gold Nanoparticles (AuNPs) and Nanoclusters with controlled sizes. Objective is the establishment of a library of suitable candidates for future investigations of bioaccumulation and biodistribution. Citrate capped AuNPs with core diameters of 5, 13, 18 and 25 nm were synthesized following established protocols.1 To enhance stability and biocompatibility, particles were coated with poly(isobutylene-alt-maleic anhydride) (PMA) via PEGylation (PEG@AuNPs) followed by Dodecylamine (DDA) modification.1 This approach yielded non-toxic, stable PMA coated AuNPs with different core sizes. To explore size-dependent effects also on smaller particles below 2 nm, N-acetyl-L-cysteine (ACC) and 6-aza-2-thiothymine (ATT) stabilized nanoclusters (1.6 nm and 1.4 nm respectively) were synthesized.2 However, ATT-stabilized clusters showed poor stability under physiologically relevant ionic conditions and were therefore excluded from the final library. The resulting collection of stable, surface-engineered AuNPs and nanoclusters provides a platform for evaluation of size- and surface-dependent biodistribution and bioaccumulation, with potential implications for nanoparticle-mediated diagnostics and therapeutic applications.

1 Selected Standard Protocols for the Synthesis, Phase Transfer, and Characterization of Inorganic Colloidal Nanoparticles; J. Hühn, et al.; Chemistry of Materials 2017 29 (1), 399-461; DOI: 10.1021/acs.chemmater.6b04738
2 Size- and Ligand-Dependent Transport of Nanoparticles in Matricaria chamomilla as Demonstrated by Mass Spectroscopy and X-ray Fluorescence Imaging; Y. Liu, et al.; ACS Nano 2022 16 (8), 12941-12951; DOI: 10.1021/acsnano.2c05339

Speaker: Magdalena Massar (Universität Hamburg)

47 Unraveling the mechanism of iron sulfide nanosheet formation: insights from in situ X-ray diffraction and photon-in photon-out spectroscopic studies

The ability to control the morphology of colloidal nanoparticles is fundamental in materials science, as their shape directly determines their physical and chemical properties. Understanding the processes that guide the formation of nanoparticles into a specific shape is crucial for bridging the gap between synthesis and application. Here, we investigate the mechanism governing the formation of crumpled Fe3S4 nanosheets in solution. We developed a unique colloidal synthesis at 180 °C, which we monitored using a combination of in situ synchrotron X-ray methods. In situ powder X-ray diffraction analysis reveals the formation of FeS as a crystalline intermediate of the reaction. Owing to its layered structure, this intermediate nucleates anisotropically into 2D nanosheets and subsequently transforms into Fe3S4, while partially preserving the nanosheet-like structure. Additionally, in situ high energy resolution fluorescence detected X-ray absorption near edge structure (HERFD-XANES) and valence-to-core X-ray emission spectroscopy (vtc-XES) enable us to monitor in real-time the evolution of the electronic structure during the reaction. By integrating experimental and theoretical data, we identify distinct components along the reaction pathway: precursor, molecular intermediate, crystalline intermediate, and final product. Initially, the Fe(acac)3 precursor reduces and coordinates with solvent molecules to form [Fe(acac)2(benzyl alcohol)2] complex, which converts into FeS and ultimately into Fe3S4. We capture the transition from oxygen- to sulfur-based coordination. Therefore, we demonstrate that the combination of in situ X-ray diffraction and spectroscopic methods provides key mechanistic insights into the formation of 2D nanostructures, offering valuable understanding of transition metal sulfides with relevance not only to materials science, but also to geochemistry and mineralogy.

Speaker: Cecilia Zito (University of Hamburg)

48 ηF (ETA factor) is involved in translation pace regulation in kinetoplastids

Kinetoplastids are a group of flagellated unicellular eukaryotes, which includes species infectious to mammals such as Trypanosoma cruzi, Trypanosoma brucei and Leishmania spp, the causative agents of Chagas disease, Sleeping sickness and Leishmaniasis, respectively. Current treatments against these parasites are in its majority based on non-specific drugs with aggressive side effects in addition to increasing drug resistance issues. The ribosome is a choice target for a wide range of therapeutic molecules (antibiotic). When compared to mammals, the kinetoplastids ribosome presents numerous structural differences that suggest a level of variability in the regulation of their mRNA translation process.
Among these structural differences, figures an interesting functionally uncharacterized protein that we have termed η (ETA) factor. ηF is a kinetoplastid-specific factor that was first observed by our team on the intersubunit side of the 40S platform from T. cruzi in late-log phase of cells growth. Its specific interactions extend to the ribosomal P and E -site where its main core binds near the platform region on the 40S subunit. Our cryo-EM structure shows that its binding clashes with the association of the 40S subunit, but also with the recruitment of eIF2-ternary complex and mRNA attachment to the 43S pre-initiation complex (PIC), acting possibly as a regulatory factor related to downregulate the formation of the PIC on the 40S and the formation of the 80S. Finally, in order to study its possible role, we have setup in vitro translation assays from Leishmania tarentolae cell extracts, where we use ηF (expressed and purified from E.coli) in increasing concentrations to show its impact on translation, but also on the formation of the PIC and the association of both ribosomal subunits.
Keywords: translation, kinetoplastids, cryo-EM

Speaker: Dr Mayara Lucia Del Cistia (1Universität Hamburg, MIN-Fakultät, Fachbereich Chemie, Institut für Biochemie und Molekularbiologie)

Poster Presentation - DESY Foyer (Building 5): Poster Session 3

49 CodSpotter

Non-invasive monitoring of marine species is critical for sustainable ecosystem management. This study presents a methodology for the individual identification of Atlantic cod (Gadus morhua) using natural skin pigmentation patterns. The project addresses the limitations of traditional, often invasive, survey methods by developing a computer-vision-based approach for re-identifying individuals over time. This allows for more accurate data on population dynamics, migratory behaviour, and site fidelity.
The methodology is founded on a robust data acquisition strategy. A substantial video dataset of wild cod has been collected in Northern Norway using Baited Remote Underwater Video Systems (BRUVs). This in-situ footage is supplemented by video from controlled aquarium environments, which will serve as a validation dataset for the developed models.
The data were integrated into a privately and custom-built web application designed to efficiently manage the extensive image datasets generated from the video footage. The application facilitates the annotation and identity verification workflow, which is a prerequisite for training a supervised machine learning model. This tool streamlines the otherwise laborious process of creating a large, accurately labelled dataset of individual cod, enabling efficient curation and review by researchers.
The subsequent phase of the project involves training a Convolutional Neural Network (CNN) to automatically re-identify individual cod from images based on their unique spot patterns. The model's performance will be quantitatively assessed using the validation dataset from the aquarium footage, where individual identities are known. The goal is to develop a reliable, non-invasive tool that can be integrated into long-term monitoring programs, thereby contributing to more effective conservation and management strategies for this commercially and ecologically vital species.

Speakers: Josephine Buntrock (nstitute for Marine Ecosystem and Fisheries Science, University of Hamburg), Juliane Niewar (nstitute for Marine Ecosystem and Fisheries Science, University of Hamburg), Kilian Huss (nstitute for Marine Ecosystem and Fisheries Science, University of Hamburg)

50 Determining the fate of engineered tRNAs in human cells by direct RNA sequencing

Engineered tRNAs designed to suppress nonsense mutations (sup-tRNAs) have a great therapeutic potential for a variety of genetic diseases. However, the effects of these tRNAs on the cell translation machinery, especially in the native tRNA pool, are still unknown. Furthermore, it remains unclear whether the sup-tRNA undergoes the same modification processes as the natural tRNAs, and how those affect sup-tRNA activity and stability. We use Nanopore direct RNA sequencing of the tRNAome to study the effect of sup-tRNAs on them and the fate of these sup-tRNAs in human cells. We combine several samples by using unique barcode sequences in RNA adapters. This allows for multiplexing and specific mapping and detection of tRNAs. We observed that the cellular tRNA pool is unaffected by administration of exogenous sup-tRNAs. Additionally, we were able to detect several modifications of the sup-tRNAs using a basecalling-error based approach. We also characterized the cellular tRNA stability and the kinetics of modifications of distinct sup-tRNAs carrying different amino acids. These results provide a framework in understanding the effect of these new sup-tRNA therapeutics. Furthermore, our new workflows for tRNA analysis expands the possibilities of RNA sequencing with Nanopore.

Speaker: Mr Daniel Koëster (Universität Hamburg)

51 Improving the mechanical strength and photocatalytic activity of 3D-structured titania aerogels by ALD coating

Aerogels are nanoporous, exceptionally lightweight materials with a large internal surface area, and they maintain the properties of their nanoscopic building blocks at the macroscale. These properties make aerogels attractive for catalytic applications. However, the production of aerogels typically lacks control over the structure at larger length scales. To address this limitation, we employed direct ink writing to 3D print a titanium dioxide nanoparticle-based aerogel. This extrusion-based additive manufacturing technique enabled hierarchical structuring of the material.

One challenge in working with aerogels is their high fragility. Although they can carry many times their own weight, aerogels are brittle and easily break under mechanical stresses. This issue is exacerbated by 3D printing, as the high shear forces during extrusion disrupt the aerogel microstructure. To address this, we employed atomic layer deposition (ALD) to improve the mechanical properties. This deposition technique enabled conformal coatings inside the nanopores of the aerogel, potentially overcoating cracks and breaking points. Nanoindentation measurements showed a recovery of hardness and an increase in elastic modulus after ALD coating of the 3D-printed aerogels.

The titania aerogels have been applied in photocatalytic water splitting, where periodic 3D microstructuring enhances gas permeability compared to a monolithic aerogel while maintaining the high light-harvesting efficiency of the nanoporous material. ALD coating improved the photocatalytic activity of the aerogels by enhancing nanoparticle interconnectivity. Calcination further enhanced photocatalytic activity by crystallizing the amorphous titania coating into anatase. The combined effects of ALD coating and calcination resulted in a 20-fold increase in hydrogen evolution from 16.5 ppm to 325 ppm.

Speaker: Malte Maximilian Schmidt (Universität Hamburg)

52 Influence of Hydrophilicity on the Hydrovoltaic Power Generation from Carbon Nanoparticles

Water is the largest carrier of energy on the Earth, but negligible amount of this energy has been harnessed. This has prompted researchers to explore the Hydrovoltaic effect, which refers to the generation of electricity from the interaction of water with nanostructured surfaces. Nanoporous materials show promising performance in this regard due to their ability of spontaneous imbibition of fluids. In this vein, most of the research on carbon-based materials focusses on 2D-materials like carbon-black, graphene and its derivative materials. In this talk, electricity generation from the ambient evaporation of water using a hermetically sealed Hydrovoltaic cell comprised of porous carbon nanoparticles will be discussed; along with the influence of surface hydrophilicity of these carbon nanoparticles on the power generation. The primary advantage of hermetic Hydrovoltaic cell being the insulation from environmental conditions that it provides. In addition, the nitric acid treatment of carbon nanoparticles improved their hydrophilicity and increased their O-atom content. Moreover, the morphology and mesoporous nature of carbon nanoparticles was largely preserved during acid treatment. However, a general decreasing trend in the BET surface area was observed in the samples as the concentration of nitric acid was increased. The increment in the O-content from 3% to 20% resulted in the enhancement of Hydrovoltaic voltage generation by up to 125%. The hermetically sealed device was able to provide a steady maximum voltage output of 450 mV for a period of 48 hours. The voltage output can be further enhanced by connecting several such devices in series. These findings provide an avenue for exploiting low-grade ambient heat for electricity generation

Speaker: Dr Sanjay Jatav (University of Hamburg/ DESY)

53 Intra- and Post-Synthesis Optimization of thermochromic α-NiS Nanoparticles

When designing new materials, one promising strategy is to combine different components to create sensitive or tunable physical and chemical properties. Nanomaterials that exhibit intrinsic functional responses – such as electrochromic, thermochromic, or photochromic behavior – play an important role in advancing innovative material technologies, particularly in electrochemical, catalytic, or sensing applications. A notable example is alpha-nickel sulfide (α-NiS)[1], which is recognized for its tunable thermochromic characteristics that can be tailored through precise synthesis methods and careful control of phase purity. In this study, we systematically investigate how varying synthesis parameters influence the formation of α-NiS nanoparticles, their subsequent transfer into polar solvents, and how these processes impact factors such as colloidal stability, particle aggregation, and the resulting thermochromic response. Comprehensive characterization using transmission electron microscopy (TEM), dynamic light scattering (DLS), and UV-visible spectroscopy – including cryogenic measurements – is employed to robustly evaluate the structural and functional properties, as well as the dispersion stability of the nanoparticles. This integrated analytical approach provides a solid foundation for the targeted investigation and future application of stimuli-responsive nanostructures and hybrid material systems. Looking ahead, additional promising candidates such as tungsten trioxide (WO₃)[2] will be considered for further studies due to their favorable properties for tunable materials.

[1] R. Himstedt, D. Baabe, C. Wesemann, P. Bessel, D. Hinrichs, A. Schlosser, N. C. Bigall, D. Dorfs, J Phys Chem C Nanomater Interfaces 2021, 125, 26635-26644.
[2] S. Heo, J. Kim, G. K. Ong, D. J. Milliron, Nano Lett 2017, 17, 5756-5761.

Speaker: Ole Krüger (Universität Hamburg)

54 Molecular Mechanisms of Long-Distance Signaling in Plants

The Molecular Plant Genetics group at the University of Hamburg focuses on understanding the molecular mechanisms that enable plants to exchange information between their tissues and organs and adapt to changing environmental conditions.

A central theme of the group's research is the study of long-distance signalling in plants, particularly the mobile macromolecules that serve as messengers under stress conditions. These signals are often transported through the vascular system, such as the phloem, allowing communication between distant parts of the plant to coordinate systemic responses to biotic and abiotic challenges. Several projects investigate the role of mobile RNAs and RNA-binding proteins in plant communication and also plant-pathogen interactions.

In this context, biomolecular RNA-protein condensates have emerged as new players regulating RNA stability, storage, and transport. The research explores the mechanisms of RNA movement within the plant and between organisms, the features that enable RNA mobility and stability during transport, and how these macromolecules contribute to regulating plant growth, development, and stress responses.

To achieve these goals, the group employs a wide range of molecular, genetic, and biochemical methods, including classical plant genetics, advanced molecular biology techniques, plant transformation, and analytical approaches such as mass spectrometry. The majority of the work is conducted in the model plant Arabidopsis thaliana and the important crop plant Brassica napus.

In addition to illuminating fundamental aspects of plant biology, this research has potential applications in agriculture and biotechnology, aiming to develop more resilient crop varieties.

Speaker: Anton Reza (Universität Hamburg)

55 Photoactivated Titania Nanocrystal Chemiresistors for the Detection of VOCs

Traditional metal oxide (MOX) gas sensors are widely used due to their high sensitivity and low cost of fabrication. However, such resistive sensing elements require high operating temperatures (> 250 °C), are difficult to integrate, and feature only limited chemical selectivity. Addressing these problems, photoactivated resistive MOX sensors, which can be operated at room temperature, are attracting increasing attention.

In this work, we investigate the sensing mechanism of photoactivated chemiresistors based on titania nanocrystal (TNC) thin films. The structural properties of the films fabricated from differently shaped TNCs are characterized by XRD, AFM, and SEM. Further, the photocurrent and its perturbation by the photoactivated reaction with volatile organic compounds (VOCs) is studied via in situ charge transport measurements. Adjusting the irradiance of the photoactivation is presented as an additional opportunity to tune the chemiresistive response characteristics. To correlate the photocurrent response with the amount of adsorbed analyte molecules, these charge transport measurements are combined with microgravimetric measurements. First results reveal that these photoactivated sensors are highly selective towards alcohols. This pronounced selectivity is attributed to the selective binding of alcohols to unsaturated Ti3+ species on the surface of the nanocrystals and their subsequent oxidation to aldehydes or ketones. As part of these investigations, the influence of humidity on the gas sensing mechanism is investigated, posing a challenge for technological applications of these sensors under ambient conditions by impeding the chemiresistive responses. To address this loss of sensitivity, the photoactivated sensors are further operated at slightly elevated temperatures.

Speaker: Finn Dobschall (Universität Hamburg)

56 Topology and Origin of Complex Nano-Scale Spin Textures

Topology is a powerful concept for describing material properties. In magnetism, topological phenomena emerge when spins within a material point in different directions, giving rise to three-dimensional non-coplanar magnetic order. A prominent example is the magnetic skyrmion, a particle-like state in which the spins wrap around the unit sphere. Such non-coplanar spin textures can result from the competition between different magnetic interactions. Another origin is geometric frustration, as found, for instance, in antiferromagnets on triangular lattices. Non-coplanar magnetic states are characterized by a finite scalar spin chirality, which can manifest in an additional, topological contribution to the Hall effect as well as in an orbital magnetization.
Here, we present spin-polarized scanning tunneling microscopy experiments on systems with complex spin textures, enabling real-space imaging of these magnetic structures at the atomic scale [1]. The driving forces behind the formation of such exotic ground states are revealed through density functional theory calculations combined with atomistic modeling. The magnetic structures we address range from ferromagnetic to nanoscale non-coplanar and collinear antiferromagnetic states. Particle-like magnetic objects such as skyrmions and merons are observed both as isolated entities that can be created and annihilated individually [2-3] and as assemblies that form chains or two-dimensional periodic arrays [4-8]. Two examples of complex topological magnetic domain walls that emerge in otherwise simple magnets will be presented. Additionally, we identify magnetism-driven structural modifications that can be exploited to generate antiferromagnetic domain-wall networks [9] or to act as templates for magnetism-induced anisotropic growth [10]. Taken together, our work on model-type systems provides a versatile toolbox for tailoring magnetic order with respect to length scale, dimensionality, and spin arrangement which are key ingredients for advancing future spintronic applications.

Speaker: Arved Heilmann (Department of Physics, University of Hamburg)

57 Translating the hygroscopic principles of explosively dehiscent fruits into bioinspired actuators

Plants have evolved a range of reversible and irreversible, active and passive movements which are often triggered and/or driven by environmental cues such as light, temperature and humidity. Some of these movements rival the accelerations observed in the animal kingdom. Among the fastest plant movements is the explosive dispersal of seeds facilitated by the release of stored elastic energy previously built up by, and stored in drying lignified fruit tissues.
In this study, we investigate the dispersal mechanism of the sandbox tree (Hura crepitans, Euphorbiaceae), whose orange-sized fruits compose of up to 16 carpels that undergo pronounced deformations during drying. Initially constrained by their macroscopic arrangement, internal stresses are accumulated upon progressive tissue desiccation. Once a critical threshold is reached, rupture occurs at predetermined fracture sites, initiating explosive seed release.
We examined this mechanism across hierarchical structural levels (millimeter to nanometer scale) by combining multiple imaging techniques, including high-speed imaging, UV Micro-Spectrophotometry (UMSP), small-angle X-ray scattering (SAXS), micro-computed tomography (µCT), and nano-holotomography (nanoCT), combined with advanced 3D analysis tools such as digital volume correlation (DVC) and finite element analysis (FEA). Our multiscale analysis reveals how fruit geometry, cell orientation, anisotropic shrinkage, and the degree and composition of lignification together facilitate this rapid actuation.
Based on these insights, we translated the functional principle into a 4D-printed actuator composed of wood–plastic composite (WPC), which mimics the strain accumulation and release dynamics of the natural system. These bioinspired actuators demonstrate substantial movement and offer a platform for biodegradable seed dispersal devices aimed at reforestation, as well as novel autonomous material systems, going beyond biology, that can be tailored to respond to thermal, pneumatic, solar, or electrical stimuli.

Speaker: Fabian Scheckenbach (Biomimetics Group, Institute of Wood Science, Department of Biology, University of Hamburg, Germany.)

58 Whispers in the WAVEs: Decoding Campus Vibrations with Distributed Acoustic Sensing

Decoding Campus Vibrations with Distributed Acoustic Sensing.

Speaker: Vincent Wodtke (University of Hamburg)

59 X-Ray Fluorescence Microscopy based Cell Discrimination using Inorganic Nanoparticle Tag

Cell cultures are a crucial tool in biological science. To accurately mimic complex human tissues, heterogeneous co-cultures consisting of different cell types are essential. However, traditional methods for identifying individual cells in these mixes lack spatial resolution, are destructive, or require thin slicing. Here, we show the use of inorganic nanoparticle tags for X-ray fluorescence imaging (XFI) as a powerful, non-destructive, and high-resolution approach to analysing cell distribution.
We screened 11 different nanoparticle syntheses to identify the 4 best candidates, based on gold (Au), iron (Fe), Nickel (Ni), and Bismuth (Bi) for high-contrast, spectrally unique XFI signals. Using these selected tags, we successfully labelled four different cancerous cell lines (HeLa, MCF7, A549, and 4T1) in a mixed cell culture. Using the hard X-ray microprobe at beamline P06 (PETRA III, DESY), we performed high-sensitivity XFI to achieve simultaneous identification and spatial mapping of all four cell types based on their individual NP signatures, confirming the method's precision and lack of spectral interference.
This work establishes a robust XFI framework for non-destructive, multiplexed cellular imaging, distinguished by its high sensitivity and spatial resolution, enabling precise, non-destructive, and multiplexed cellular mapping in 2D co-cultures. Furthermore, the innate deep-penetration capability of hard X-rays provides a direct and seamless pathway to apply this same methodology to complex 3D tissue models. This versatility unlocks new possibilities for studying cellular interactions in realistic tumour microenvironments and evaluating drug response.

Speaker: Maya Luongo (Universität Hamburg)

Poster Presentation - DESY Foyer (Building 5): Poster Session 4

60 Aerogels made from Semiconductor Nanoparticles

Nanoparticles are tiny structures with a diameter in the nanometer range that have become increasingly important in recent years due to their unique properties, such as a high surface-to-volume ratio. Semiconductor nanocrystals stand out in this regard because their band gap can be altered due to the quantum size effect, which enables the excitation of charge carriers by visible light. When these nanocrystals are assembled into hyperbranched structures, not only do they retain their special properties, but macroscopic monoliths with nanoscopic properties are also created. This also allows the surrounding liquid medium to be replaced and ultimately removed to form an air-permeable aerogel, making them attractive for future applications in catalysis and sensors. E.g. a solution of ligand-stabilized nanocrystals can be destabilized using an oxidizing agent, whereby this process slowly leads to the formation of a large, highly porous network with direct crystal-to-crystal contacts. The design of the nanocrystals and how they connect heavily influence the structure of the gel and its chemical properties. When a semiconductor-based hydrogel with water in the pores is exposed to radiation, charge carriers inside the nanocrystals can separate and move beyond a single building block, enhancing their ability to produce hydrogen as catalysts. Since the nanocrystals are fixed within the network, they cannot agglomerate any further, which improves catalytic efficiency. Several factors, such as the material composition, types of hole scavenging agents, and how the particles connect, influence the properties of these structures. [1] [2]

[1] Jakob Schlenkrich, Franziska Luebkemann-Warwas, Rebecca T. Graf, Christoph Wesemann, Larissa Schoske, Marina Rosebrock, Karen D. J. Hindricks, Peter Behrens, Detlef W. Bahnemann, Dirk Dorfs, Nadja C. Bigall, Small 2023, 2208108
[2] Anja Schlosser, Lea C. Meyer, Franziska Luebkemann, Jan F. Miethe, Nadja C. Bigall, Phys.Chem.Chem.Phys., 2019, 21, 9002

Speaker: Pia Thomsen (Universität Hamburg)

61 Cation‐Site Disordered Cu3PdN Nanoparticles for Hydrogen Evolution Electrocatalysis

¬¬Transition metal nitrides (TMNs) are emerging as a promising class of materials for application in optoelectronics as well as energy conversion and storage, but they remain rather unexplored, mainly due to a lack of mechanistic understanding of their synthetic pathways. Here we demonstrate a one-pot synthesis, which yields 3 nm phase-pure Cu3PdN nanoparticles after the reaction of Cu methoxide and Pd acetylacetonate in benzylamine for 5 minutes at 140°C. We reveal the structure of the initial complexes and their conversion to Cu¬3PdN by in situ x-ray absorption spectroscopy measurements and elucidate nucleation and growth of the nitride nanocrystals by in situ total x-ray scattering measurements. Interestingly, extended x-ray absorption fine structure double-edge refinement reveals the presence of short-range cation-site disorder in the anti-perovskite structure of Cu3PdN, which has not been observed before in the Cu3PdN system. Additionally, the synthesized Cu3PdN nanoparticles are tested for the electrocatalytic hydrogen evolution reaction revealing an overpotential as low as η10 = 212 ± 11 mV measured at 10 mA/cm2.

Speaker: Jagadesh Kopula Kesavan (Universität Hamburg)

62 Efficient workflow for demultiplexing and mapping of direct tRNA sequencing

Accurate classification and analysis of transfer RNAs (tRNAs) using Nanopore sequencing remain challenging due to the high similarity among tRNAs and basecalling errors induced by RNA modifications. We have created a robust workflow for direct tRNA Nanopore sequencing that addresses these challenges through optimized barcoding, demultiplexing, and read mapping strategies. We used barcoding sequences within RNA adapters for precise classification of reads post-basecalling with the Dorado demultiplexing tool We optimized the demultiplexing parameters to ensure high accuracy while minimizing read loss during the demultiplexing process. Additionally, mapping strategies were refined to minimize multimapping events arising from tRNA sequence similarity and modification-related errors, ensuring accurate downstream analysis. This workflow enables the accurate classification of tRNA Nanopore reads across six barcodes, offering a reliable and efficient approach for tRNA sequencing applications. By mitigating common sources of error and optimizing critical processing steps, our work provides a significant advancement in the field of tRNA Nanopore sequencing and its application in understanding tRNA biology.

Speaker: Daniel Köster (Universität Hamburg)

63 Green Synthesis of Complex Chemical Building Blocks: Light-Mediated Oxygenation of Phenols

Photooxygenations provide a sustainable access to functionalized organic molecules, using visible light as an abundant energy source for small molecule activation and molecular oxygen as a cheap oxidant. A dye operates as an energy mediator, exciting the triplet ground state of molecular oxygen into its singlet excited state which is not merely a highly reactive species but rather a selective oxidant.[1] The reactions of singlet oxygen with alkenes and phenols to yield hydroperoxides are
well established.[1,2] Our work focuses on the synthesis of quinol epoxides 3 from simple phenol 1 feedstocks using molecular oxygen as the sole stoichiometric reagent and a quinol peroxide 2 as key intermediate.

Inspired by previous reports,[3,4] we systematically screened reaction conditions to enable the conversion of electron-rich phenols 1 into three-dimensional, highly functionalized epoxy quinol building blocks 3. Mechanistic investigations provide deeper insights into the transformation and the structure of involved intermediates,
while product derivatizations highlight the synthetic value of these structures in complex molecule synthesis.

Speaker: Ben Bimberg (Department of Chemistry, University of Hamburg)

64 Implementing electric field-stimulated X-ray crystallography at EMBL P14 T-REXX using Hadamard time-resolved X-ray crystallography

There is an ongoing need for novel experimental methods that can probe biological macromolecules with high spatiotemporal resolution, as many of the cellular functions associated with such molecules originate not from a static molecular structure, but rather from the structural dynamics over time. However, any such methods must be sufficiently accessible to readily trial on new biological systems of interest. Electric field-stimulated X-ray crystallography (EF-X) promises to deliver the requisite spatiotemporal insight by combining the structural resolution of X-ray crystallography with an electric field perturbation that can induce molecular motions within the confines of a crystal lattice (Fig. 1a) [1]. The applied electric field creates a pattern of forces, localized to the presence of charges in each molecule. As these charges are natively present in both proteins (as charged amino acids) and nucleic acids (as the sugar-phosphate backbone), no molecular labeling or other alteration to the system is required in order to use the electric field to trigger a change. The resulting motions can then be detected through X-ray diffraction as changes in the electron density (Fig. 1b).

Until 2023, EF-X experiments had only been performed at the BioCARS Laue beamline of the Advanced Photon Source at Argonne National Laboratory (USA). Like many time-resolved crystallographic methods, EF-X used the polychromatic beam to achieve sufficient photon flux for very fine (ps) time resolution. There are very few Laue beamlines available worldwide, however, posing a barrier to researchers wishing to conduct EF-X experiments who are not based in the US. Moreover, processing Laue diffraction data is significantly more challenging than its monochromatic equivalent. To meet this need, we have recently begun work to expand access to EF-X by pairing it with Hadamard time-resolved X-ray crystallography (HATRX), thus making it compatible with monochromatic
beamlines.

HATRX circumvents the flux-induced limitations on achievable time resolution at monochromatic synchrotron beamlines by multiplexing multiple time points into a single diffraction image [2]. Repeating this measurement with different combinations of time points, selected according to a Hadamard encoding matrix, enables subsequent deconvolution of the resulting diffraction intensities to yield the underlying time-resolved data (Fig. 1c). This method was first demonstrated in 2014, with a time resolution of 200 ms. Here, we present proof-of-concept data for a Hadamard implementation of EF-X (EF-HATRX) on the T-REXX endstation of the EMBL P14 beamline at the DESY synchrotron in Hamburg (Fig. 1d). Though an optimized EF-HATRX data processing pipeline is still under development, preliminary data analysis suggests that by weighting the encoding matrix (i.e., including time points of different lengths), we can obtain signal down to sub-µs time resolution.

Speaker: Maggie Klureza (Department of Physics, University of Hamburg)

65 Liposome-based SERS Sensor system for double readout of intracellular Iron concentrations and pH changes

Liposome-based SERS Sensor system for double readout of intracellular Iron concentrations and pH changes
AUTHORS: Chengxiu Wei, Robbert Schütt, Irene Calderon-Gonzalez, Florian Schulz, Mathias Winterhalter, Ramon Alvarez-Puebla, Wolfgang Parak.
ABSTRACT: Nanoscopic sensor systems based on Fluorescence and SERS microscopy are commonly employed for the detection of biologically relevant ions in cells and remain promising tools for advancing medical diagnostics and enhancing the understanding of ion-related processes. While these techniques allow spatially and temporally resolved read out of even low ion concentrations, a common barrier encountered in developing robust optical ion sensors for applications in diagnostics or bio-sensing is crosstalk with the pH of the sample. Often, the reporter molecules employed for binding the ions of interest and enabling readout via fluorescence or SERS microscopy are highly sensitive to the pH prevalent in biological samples. Among the biologically and medically relevant ions, iron stands out as being one of the most abundant and important ions. Given the rising interest in Ferroptosis, the accurate, localized and time resolved measurement of intracellular iron concentrations has become crucial in deepening the understanding of this process.
Here, we present an iron and pH double readout sensor system, enabled by a very versatile sensor system that is based on the amine-promoted decoration of polystyrene beads with silver nanoparticles and their subsequent encapsulation within liposomes. The iron sensor utilizes hydrophobically entrapped phenanthroline within the liposomal bilayer, while the pH sensor utilizes covalently bound 4-mercaptobenzoic acid. The liposome coating provides biocompatibility, hydrophobic entrapment, and tuneable membrane properties, for example through the choice of lipids with specific phase transition temperatures or by incorporating unsaturated fatty acids such as oleic acid to modulate membrane permeability. Combining the two SERS sensors allows for the simultaneous differentiation between false positive iron concentration readouts induced by pH changes and actual positive readouts caused by changes in iron concentration. Furthermore, the combination of microscopic images, pH readout, and liposomal encapsulation could help refine the accurate localization of the sensor system, distinguishing between acidic endosomes and the neutral cytoplasm. In processes such as ferroptosis, the simultaneous read out of pH changes and the iron concentration in lysosomes could uncover new correlations and deepen our understanding of this process. Finally, we are conducting single-particle analyses to confirm the structural of the liposome-coated sensors and to assess their responsiveness and stability under biologically relevant conditions.”

Speaker: Chengxiu Wei (Universität Hamburg)

66 Modular Reactor for In Situ X-ray Scattering, Spectroscopy, and ATR-IR Studies of Solvothermal Nanoparticle Synthesis

Modular Reactor for In Situ X-ray Scattering, Spectroscopy, and ATR-IR Studies of Solvothermal Nanoparticle Synthesis

Tjark R. L. Groene,¹ Sani Y. Harouna-Mayer,^1,2 Melike Gumus Akcaalan,¹ Jagadesh Kopula Kesavan,^1,2 Lars Klemeyer,^1,2 Sarah-Alexandra Hussak,^1,3 Lukas Grote,¹ Davide Derelli,¹ Francesco Caddeo,¹ Cecilia Zito,^1,2 Paul Stützle,¹ Dorota Speer,¹ Ann-Christin Dippel,³ Blanka Detlefs,⁴ Yannik Appiarius,⁵ Axel Jacobi von Wangelin,⁵ Dorota Koziej^1,2*

1. University of Hamburg, Institute for Nanostructure and Solid-State Physics, Center for Hybrid Nanostructures, Luruper Chaussee 149, 22761 Hamburg, Germany
2. he Hamburg Center for Ultrafast Imaging, 22761 Hamburg, Germany
3. Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany.
4. ESRF, The ESRF, The European Synchrotron, 71 Avenue des Martyrs, CS40220, 38043 Grenoble, Cedex 9, France
5. University of Hamburg, Department of Chemistry, Martin Luther King Platz 6, 20146 Hamburg,

We describe a novel reaction reactor for in situ X-ray scattering and spectroscopy with liquid or gas injection capabilities. The reactor enables autoclave-like conditions for solvothermal synthesis, with heating up to 200 °C at pressures of up to 8 bar, as well as cooling to −20 °C to decelerate rapid reduction processes such as those occurring during cluster formation. Optional ATR IR or injection can be performed simultaneously by the choice of different caps for the inlet. While conventional ex situ techniques usually provide information only on the final products, the underlying reaction mechanisms often remain obscured, potentially missing crucial intermediate steps. However, a deeper insight into the reaction step is of great interest to tailor material properties, especially for those at the nanoscale.[1],[2],[3] To shine a light on these mechanisms, our multi-purpose in situ cell standardises reaction procedures across a wide range of non-invasive monitoring methods with a strong focus on high flux synchrotron radiation. Capabilities of the cell to fetch complexation and cluster intermediates have been demonstrated for Cu3PdN, ZnS and Fe3O4 nanoparticles.[4],[5],[6]

1. Cansell, F. and Aymonier, C. (2009) The Journal of Supercritical Fluids, 47(3), pp. 508–516.
2. Deshmukh, R. and Niederberger, M. (2017), Chemistry – A European Journal, 23(36), pp. 8542–8570.
3. Terraschke, H. (2023) Nanostructured Materials: Applications, Synthesis and In-Situ Characterization.
4. Sani Y. Harouna-Mayer, Small, Vol 21,33 (2025) (https://doi.org/10.1002/smll.202506838)
5. L. Klemeyer et al., JACS, Vol. 146, 49, 10 S. (2024) (https://doi.org/10.1021/jacs.4c10257)
6. L. Klemeyer et al., ACS Nano, 19, 28, 25710–25719 (2025) (https://doi.org/10.1021/acsnano.5c02875)

Speakers: Melike Gumus Akcaalan (Universität Hamburg), Sani Harouna-Mayer (Universität Hamburg), Tjark Leon Raphael Gröne (Universität Hamburg)

67 Quantum Radiometric Calibration

Optical quantum computing, as well as communication and sensing technology based on quantum correlations are in preparation. These require photodiodes for the detection of about 10^16 photons per second with close to perfect quantum efficiency. Already the radiometric calibration is a challenge. The Heisenberg uncertainty principle combined with the measurement of squeezed light represent a quantum approach to radiometric calibration. Here we provide the theoretical description of the quality of this quantum radiometric calibration method and experimentally reduce the largest error contribution by 1.5 orders of magnitude. Unlike all existing methods, ours is in situ and provides both the detection efficiency and the more stringent quantum efficiency directly for the frequencies of the user’s detection band. We calibrate two of the most efficient commercially available photodiodes at 1550 nm to a detection efficiency of (97.20 ± 0.37) % using 10-dB-squeezed vacuum
states as the quantum correlation resource. The value is unexpectedly low and not sufficient for optical quantum computing.

Speaker: Leif Albers (Department of Physics, University of Hamburg)

68 Strategic Phosphorus Allocation Under Stress: Root-Mycorrhizal Traits Driving Nutrient Efficiency in Forests

Phosphorus (P) limitation and intensifying drought critically constrain forest productivity. Beyond the total amount of P in plants, its allocation (how it is divided among different biochemical fractions) strongly influences how efficiently plants use P and how well they cope with stress. These fractions include inorganic phosphate, nucleic acid P (a key component of DNA and RNA), phospholipid P (a key component of cell membranes), and metabolite P (involved in energy transfer and metabolic regulation).

My research has shown that greater allocation to nucleic acid P supports active protein synthesis and cellular repair, while higher phospholipid P helps maintain membrane integrity. Together, these contribute to plant stress resilience—the ability of plants to maintain function and recover from environmental pressures.

Root functional traits, such as carboxylate exudation (the release of negatively charged salts derived from organic acids, e.g., citrate or malate), help mobilise otherwise inaccessible P by binding to and releasing it from mineral surfaces like iron or aluminium oxides. Mycorrhizal associations further expand the soil volume accessible for nutrient uptake and mediate long-term plant–soil feedbacks.

However, the combined influence of P fraction allocation, root exudation, and mycorrhizal function under simultaneous P and drought stress remains poorly quantified, limiting our ability to predict forest resilience. In the anticipated second phase of the DFG research group "Forest Floor" (https://uni-freiburg.de/forestfloor/), by explicitly linking biochemical P allocation with root and mycorrhizal traits under realistic dual-stress conditions, my research will: (1) advance mechanistic understanding of forest nutrient efficiency, covering both P acquisition and use under stress, (2) improve predictions of carbon–nutrient dynamics under climate change.

Speaker: Li Yan (University of Hamburg)

69 Unravelling Protein Dynamics: Advancing Structural Biology with Time-Resolved Crystallography

Proteins are dynamic molecular machines, and their ability to function depends not only on their 3-dimensional structure but also on subtle motions, cooperativity, and long-range communication between distant sites. However, capturing these processes at high resolution is often compounded with substantial experimental challenges [1,2]. To address this, we develop and apply advanced crystallographic methods, which we use at synchrotrons and free electron laser sources [3]. These include ultra-high-resolution crystallography, novel cryo-trapping methods (Spitrobot [4,5], microED), as well as time-resolved, multi-temperature, and multi-dimensional X-ray diffraction [6,7]. These approaches enable the direct observation of protein motions, enzymatic reaction and ligand binding events as they occur. By revealing phenomena like ‘molecular breathing’ during catalysis, half-the-sites reactivity without significant conformational change, and meta-stable intermediates during drug binding or substrate catalysis, they have provided unique insight into the function and dynamics of proteins. In addition to these insights, our methods enable to map cooperativity and allosteric networks inside enzyme complexes, bridging the gap between dynamic functional behaviour and static structural snapshots. Furthermore, we combine this insight with biochemical results and integrate them with insight from other biophysical methods, such as NMR-spectroscopy or MD-simulations. By resolving these dynamic processes, structural biology is advancing from static models towards a mechanistic understanding of protein function at atomic detail, offering a framework to interpret enzyme activity and regulation and develop focused therapeutic strategies.

Speaker: Maria Spiliopoulou (Universitätsklinikum Hamburg-Eppendorf (UKE))

Life Sciences: Session Block 2, CSSB Building 15

Chair: Baris Tursun

70 Demystifying the mechanics of protein function

TBC

Speaker: Helen Ginn (Department of Physics, University of Hamburg / Deutsches Elektronen-Synchrotron, DESY)

71 Species-Specific Aspects in Eukaryotic mRNA Translation Modulation and their Implications in Diseases

TBC

Speaker: Yaser Hashem (Universität Hamburg, MIN-Fakultät, Fachbereich Chemie, Institut für Biochemie und Molekularbiologie)

72 Ubiquitin’s Double Edge: Proteostasis at the Crossroads of Life and Death during Infection

TBC

Speaker: Marco Trujillo (Department of Biology, University of Hamburg)

73 Functional Ecology as a Tool for Predicting Ecosystem Responses to Climate Change

Ecosystems influence global climate and can lead to an acceleration or deceleration of climate change. As climate change continues almost unregulated, reliable predictions about the feedback of ecosystems to global changes are becoming increasingly urgent. At the same time, however, we still have difficulty simplifying the complexity and diversity of ecosystems in such a way that the information can be reliably reflected in calculated predictions. In functional ecology, we categorize the role of species in ecosystems based on the relationship between functional characteristics and ecosystem processes, thus enabling the use of categorized information in models. In my Heisenberg research project, I focus on the mycorrhizal symbiosis between tree roots and fungi as possible functional grouping of tree flora. Most tree species are associated with either arbuscular mycorrhizal fungi or ectomycorrhizal fungi, which supply their hosts with mineral nutrients in exchange for carbon. Since the two types of mycorrhiza differ fundamentally in their nutrient balance, mycorrhizal type represents a possible grouping that is relevant for the carbon cycle and nutrient binding in forests. In my presentation, I will (i) derive the significance of the mycorrhizal type as functional grouping for understanding biogeochemical cycles in forests under climate change, (ii) present some findings on the influence of mycorrhization on biodiversity effects in temperate and tropical forests, and (iii) discuss open knowledge gaps on biotic interactions and their role in ecosystem-climate feedbacks.

Speaker: Ina Christin Meier (Universität Hamburg)

74 From Host-Pathogen Coevolution to Precision Medicine

TBC

Speaker: Tobias Lenz (Universität Hamburg)

75 Breaking Fat: Targeting Lipid Trafficking for Host-Directed Therapies Against Mycobacteria

TBC

Speaker: Caroline Barisch (CSSB)

76 UHH Core Research Area Inflammation, Infection and Immunity: Joint efforts of MIN and partners

TBC

Speaker: Kay Grünewald (Department of Chemistry, University of Hamburg)

MIN Materials: Session Block 2, CFEL Building 99

Chairs Session I: Linnea Hesse & Dorota Koziej
Chairs Session II: Nadja Bigall & Winnifried Wollner

77 BlueMat: Water-Driven Materials

Biological materials achieve an exquisite diversity and functionality through just a small number of abundant chemical elements. While engineering materials primarily use specific, often unsustainable, chemical compositions to realize their functions, nature achieves unparalleled functionality through optimized architectures that span multiple length scales. Water, with its ubiquity and unique structural dynamics, plays a pivotal role as a “working fluid” in shaping the properties and functionality of nature’s materials. Inspired by these marvels of nature, BlueMat will develop a novel class of sustainable, interactive, architected “Blue Materials” deriving their functionality from multiscale structures of hard matter interacting with water. This approach is internationally unique. We will mimic natural processes such as water-driven mechanical actuation, capillarity-driven water transport, humidity-dependent colors, and photocatalytic water splitting, as observed in animals and plants, and extend them to functionalities not found in nature, such as control of acoustic and electromagnetic waves, tunable thermal emission and electrical energy storage and generation. To this end, we will study and exploit novel effects, achieved, for example, through nanoconfinement of water. We will combine experiments with imaging and modeling from the atomic up to the device scale and bridge the gap between top-down and bottom-up fabrication methods to enable scalable production of Blue Materials. BlueMat raises and answers compelling and fundamentally new scientific questions. It promises a radically new concept to functionalize materials, and it will demonstrate the fascinating opportunities of this approach by a host of device-level applications. These include novel energy efficient windows and hydrovoltaic power generation, harvesting electrical energy from environmental processes or waste heat.

Speaker: Patrick Huber (TUHH/ DESY)

78 Plants as Architects: Lessons for Multifunctional, Stimuli-Responsive Materials

Plants are hierarchically organized porous material systems with multiple functions that are intricately driven by water transport and distribution. The interplay between material composition, structural organization, and emergent function in plants offers powerful design principles for the development of next-generation technical material systems. By translating these biological strategies, biomimetic approaches enable the development of multifunctional, autonomously responding devices that extend beyond biology by leveraging responsiveness not only to water but also to diverse external cues such as thermal, pneumatic, solar, or electrical stimuli. Unlocking these possibilities requires advances in material synthesis, precise characterization, and scalable manufacturing methods capable of reproducing hierarchical and functionalized structures from the nano- to the device level.
On the example of exploding fruits and water conductive tissues, this talk highlights recent progress in bio-inspired material research, demonstrating how insights from life sciences can fuel innovation in material systems with life-like adaptive functions. The aim is to stimulate interdisciplinary collaboration within the MIN Materials pillar and inspire synergistic projects that bridge biology and materials science to develop next-generation bio-inspired technical material systems.

Speaker: Linnea Hesse (Universität Hamburg)

79 Environmentally Benign Catalysts for Sustainable Chemistry: The Potential of Polyoxometalates

Modern chemical production still depends heavily on fossil resources such as oil, gas, and coal. These raw materials have enabled the development of fuels, plastics, and countless everyday products. Yet, if we want to build a more sustainable future, we must replace fossil feedstocks with renewable alternatives such as biomass or carbon dioxide. This shift is not straightforward: renewable raw materials differ in composition and structure, which means that many established processes cannot be applied directly. To make use of these new resources, we must redesign chemical processes from the ground up — and this includes developing new catalyst materials.
Catalysts are the hidden drivers of chemistry. They make reactions faster, more efficient, and less energy demanding. My research focuses on a special class of catalysts called polyoxometalates (POMs). These are molecular clusters composed of metal and oxygen atoms. What makes them exciting is their flexibility: they can be built in many different shapes and modified by including a variety of different elements. Because of this, POMs can be adapted to perform a wide range of useful reactions that are relevant for sustainable chemistry.
In my work, I develop methods to synthesize and study new types of POMs for specific catalytic applications. By carefully changing their composition and structure, I investigate how these changes affect their ability to promote chemical reactions. I will present examples where POM-based catalysts show potential in processes that could one day help us use renewable raw materials more efficiently and with fewer unwanted by-products.
This work is part of the broader efforts of the Albert research group, which is dedicated to designing chemical processes that are cleaner, more efficient, and better aligned with the principles of sustainability and green chemistry.
Looking ahead, our vision is to move beyond trial-and-error approaches towards rational design of catalysts — using insights from synthesis, advanced measurements, and theoretical modelling to predict and create the “right” catalyst for a given sustainable process. Through collaboration across chemistry and related fields, we aim to show how new material like POMs can help redefine chemical production in a more sustainable way.

Speaker: Maximilian J. Poller (Universität Hamburg)

80 f-Element Coordination Chemistry: Tuning Properties, Reactivity and Recycling

The f-elements (lanthanoids and actinoids) possess a variety of properties which make them invaluable or promising for a variety of applications, such as in electronics, optics or as catalysts. However, a thorough understanding on how to tune these properties on the molecular level is often lacking. This talk will highlight our approach towards a more rational design of new f-element compounds.

Speaker: Lisa Vondung (Universität Hamburg)

81 Interactive Session Part

Speakers: Lisa Vondung (Universität Hamburg), Ralf Riedinger (Universität Hamburg)

Quantum Science & Technologies: Session Block 2, ZOQ Building 90

82 A Tale of Quantum Computation and Categorification

Quantum topology is the branch of mathematics that connects entanglement in quantum mechanics with topological entanglement in low-dimensional topology, such as the knotting, tangling, and linking of strings in 3d space. At its core lie Artin’s braid groups, algebraic structures that capture the rules of intertwining strands. These same structures underpin topological quantum computation, where braids guide the motion of quasiparticles in 2d, and quantum information is stored in global topological features that make it resistant to local errors. Pushing further, categorification lifts these algebraic ideas to higher-dimensional structures, allowing us to track the movements of strings in 4d and uncover hidden symmetries. Along the way, surprising bridges emerge to both physics and computer science. I will illustrate these themes through an accessible mathematical example.

Speaker: Paul Wedrich (Universität Hamburg)

83 Linear Logic, Representations of Symmetries, and Surface Diagrams

Connectives like “and” and “or” allow us to construct sentences—whether in natural language, formal logic, or programming. In classical logic, variables within these sentences can be freely copied or discarded. However, when variables represent resources—such as quantum information—that freedom is no longer appropriate. This has motivated linear logic, a resource-sensitive refinement of classical logic.

Linear logic has models in category theory, some of which have recently been shown to arise from two-dimensional quantum field theories. I will show that calculations and proofs in these categorical models can be carried out using a rigorous three-dimensional graphical language, supported by the computer implementation homotopy.io.

Speaker: Max Demirdilek (Universität Hamburg)

84 Quantum Gravity and Geometry

Understanding the principles of quantum gravity is undoubtedly among the most important challenges for fundamental physics in the 21st century. Modern mathematics can guide the way towards uncovering such principles, especially in the context of string theory, and at the same time receives new inspiration from physics insights into quantum gravity. I will exemplify this cross-fertilisation of mathematics and fundamental physics in the context of moduli spaces of quantum gravity theories near their weak coupling regime.

Speaker: Timo Weigand (Universitaet Hamburg)

85 Machine Learning string theory effective field theories

One of the most compelling questions of string phenomenology is how to find viable inflationary models stemming from string theory. While asymptotic regions of the moduli space have been extensively explored - with limited success - little is known about inflationary dynamics in transitional, or 'penumbral', regions. In this talk, I will focus on the complex structure moduli space of Type IIB string theory compactified over Calabi-Yau three-folds. I will present evidence for flattened scalar potential valleys, which could deliver inflationary trajectories in penumbral regions of the moduli space, and I will illustrate how to obtain families of effective theories hosting such valleys by using machine learning techniques.

Speaker: Stefano Lanza (University of Hamburg)

86 Breakdown and emergence of stringy efts

Despite the huge number of different consistent low-energy effective gravitational theories that arise from string theory, there appear to be ubiquitous patterns in all such theories, which encode fundamental properties of quantum gravity. In additon, unraveling such patterns often involves a fascinating interplay between physics and geometry. In this talk, we will discuss a particular instance based in recent developments in the context of the Emergent String Conjecture.

Speaker: Jeroen Monnee (Universität Hamburg)

87 Infinite Distance Limits and Emergent Structures in Supersymmetric Conformal Manifolds

Conformal Field Theories serve as a cornerstone in theoretical physics, playing essential roles in the study of quantum field theory, string theory, statistical systems, and holography. When these theories admit exactly marginal couplings, they organize themselves into families described by conformal manifolds—moduli spaces endowed with rich geometric structures. Understanding these spaces provides a non-perturbative window into strongly coupled regimes of quantum field theories especially in four dimensions with supersymmetry.

This talk focuses on exploring the local and global structure of these conformal manifolds, with a particular emphasis on infinite distance limits in 4D Superconformal Field Theories. We aim to investigate the emergence of higher spin operators, tensionless strings, and the connections to the Swampland Distance Conjecture. The analysis combines conformal field theory techniques, representation theory, integrability, and insights from string theory.

Speaker: Fabio Mantegazza (DESY/University of Hamburg)

88 A Short Tour of 6d Field Theories

In the absence of gravity, field theories in six dimensions can be UV-completed to either Superconformal Field Theories (SCFTs) or Little String Theories (LSTs) and can be geometrically engineered from string theory. Large classes of these theories can furthermore be understood as deformations of a few "parents" through a network of Renormalisation Group flows. After reviewing some of their properties, I will show that certain protected quantities can be obtained solely in terms of group theory, without ever needing to refer to the geometric construction. For LSTs, this greatly simplifies the search for classes of theories that are related by T-duality.

Speaker: Florent Baume (Universität Hamburg)

16:30 Coffee Break

Plenary Session: Synthesis and outlook - DESY Auditorium (Building 5)

89 Wrap up: MIN Life Science

90 Wrap up: MIN Materials of the Future

Speakers: Nadja-Carola Bigall (Universität Hamburg), Ralf Riedinger (Universität Hamburg), Winnifried Wollner (Universität Hamburg)

91 Wrap up: MIN Quantum Science and Technologies

Get together - DESY Foyer (Building 5)