ERC FUNDED PROJECTS

Charge and energy transfer are the key steps underlying most chemical reactions and biological transformations. The purely electronic dynamics that control such processes take place on attosecond time scales. A complete understanding of these dynamics on the electronic level therefore calls for new experimental methods with attosecond resolution that are applicable to aqueous environments. We propose to combine the element sensitivity of X-ray spectroscopy with attosecond temporal resolution and ultrathin liquid microjets to study electronic dynamics of relevance to chemical, biological and photovoltaic processes. We will build on our recent achievements in demonstrating femtosecond time-resolved measurements in the water, attosecond pho-toelectron spectroscopy on a liquid microjet and measuring and controlling attosecond charge migration in isolated molecules. We will first concentrate on liquid water to study its electronic dynamics following outer-valence ionization, the formation pathway of the solvated electron and the time scales and intermolecular Coulombic decay following inner-valence or core-level ionization. Second, we will turn to solvated species and measure electronic dynamics and charge migration in solvated molecules, transition-metal complexes and pho-toexcited nanoparticles. These goals will be achieved by developing several innovative experimental tech-niques. We will develop a source of isolated attosecond pulses covering the water window (285-538 eV) and combine it with a flat liquid microjet to realize attosecond transient absorption in liquids. We will complement these measurements with attosecond X-ray emission spectroscopy, Auger spectroscopy and a novel hetero-dyne-detected variant of resonant inelastic Raman scattering, exploiting the large bandwidth that is naturally available from attosecond X-ray sources.

2 750 000 €

Start date: 2018-04-01, End date: 2023-03-31

Heterogeneous biomolecular mechanisms at the surface of cellular membranes are often fundamental to generate function and dysfunction in living systems. These processes are governed by transient and dynamical macromolecular interactions that pose tremendous challenges to current analytical tools, as the majority of these methods perform best in the study of well-defined and poorly dynamical systems. This proposal aims at a radical innovation in the characterisation of complex processes that are dominated by structural order and disorder, including those occurring at the surface of biological membranes such as cellular signalling, the assembly of molecular machinery, or the regulation vesicular trafficking. I outline a programme to realise a vision where the combination of experiments and theory can delineate a new analytical platform to study complex biochemical mechanisms at a multiscale level, and to elucidate their role in physiological and pathological contexts. To achieve this ambitious goal, my research team will develop tools based on the combination of nuclear magnetic resonance (NMR) spectroscopy and molecular simulations, which will enable probing the structure, dynamics, thermodynamics and kinetics of complex protein-protein and protein-membrane interactions occurring at the surface of cellular membranes. The ability to advance both the experimental and theoretical sides, and their combination, is fundamental to define the next generation of methods to achieve our transformative aims. We will provide evidence of the innovative nature of the proposed multiscale approach by addressing some of the great questions in neuroscience and elucidate the details of how functional and aberrant biological complexity is achieved via the fine tuning between structural order and disorder at the neuronal synapse.

1 999 945 €

Start date: 2019-06-01, End date: 2024-11-30

Highly excited electronic states of small atmospheric molecules play an important, but as yet little explored, role in the reactivity, and in the evolution of plasmas, including the Aurora Borealis, in the upper atmosphere of the Earth. Processes involving these highly excited states are very challenging to investigate theoretically because of the high density of states close to the ionization limits where they lie. Therefore, experimental input is essential for the identification of the reaction and decay mechanisms, and the quantum states of importance in future studies. However, experimental techniques that can be exploited to provide this input have only become available very recently. These techniques permit gas-phase molecular samples in these highly excited states to be confined in traps for sufficient lengths of time (e.g. 1 ms – 10 ms) for detailed studies to be performed in a controlled laboratory environment. They include resonance-enhanced and non-resonance-enhanced multiphoton excitation of long-lived high angular momentum Rydberg states of small molecules, and chip-based devices for efficiently decelerating, transporting and trapping these samples. With the support of this Consolidator Grant a new experimental research program will be developed in the Department of Physics and Astronomy at University College London involving laboratory based studies of (1) inelastic scattering processes, and (2) the decay mechanisms of gas-phase atmospheric molecules, including N2, O2 and NO, and their constituent atoms, in high Rydberg states. The planned experiments will be directed toward understanding the effects of static and time-dependent electric and magnetic fields, and blackbody radiation fields on slow dissociation processes that occur in highly excited states of N2, O2 and NO, investigations of collisional energy transfer processes, and studies of the role that these excited electronic states play in the evolution and reactivity of atmospheric plasmas incl

1 985 553 €

Start date: 2016-06-01, End date: 2021-05-31

"Our cells receive tens of thousands of different DNA lesions per day. Failure to repair these lesions will lead to cell death, mutations and genome instability, which contribute to human diseases such as neurodegenerative disorders and cancer. Efficient recognition and repair of DNA damage, however, is complicated by the fact that genomic DNA is packaged, through histone and non-histone proteins, into a condensed structure called chromatin. The DNA repair machinery has to circumvent this barrier to gain access to the damaged DNA and repair the lesions. Our recent work suggests that chromatin-modifying enzymes (CME) help to overcome this barrier at sites of DNA damage. However, the identity of these CME, their mode of action and interconnections with DNA repair pathways remain largely enigmatic. The aim of this project is to systematically identify and characterize the CME that operate during DNA repair processes in both yeast and human cells. To reach this goal we will use a cross-disciplinary approach that combines novel and cutting-edge genomics approaches with bioinformatics, genetics, biochemistry and high-resolution microscopy. Epigenetics-IDentifier (Epi-ID) will be used as a tool to unveil novel CME, whereas RNAi-interference and genetic interaction mapping studies will pinpoint the CME that may potentially regulate repair of DNA damage. A series of functional assays will eventually characterize their role in distinct DNA repair pathways, focusing on those that counteract DNA strand breaks and replication stress. Together these studies will provide insight into how CME assist cells to repair DNA damage in chromatin and inform on the relevance of CME to maintain genome stability and counteract human diseases."

1 999 575 €

Start date: 2014-03-01, End date: 2019-02-28