Day 1 :
CIMAP Laboratory, France
Time : 10:00-10:30
Jean-Christophe Poully is assistant professor at the University of Caen (France) since 2010. His research is focused on the intrinsic properties of biologically-relevant molecular systems, by means of experimental techniques such as mass and ion mobility spectrometries, but also quantum-chemical calculations. It allows shedding light on processes occurring after electron capture, photoabsorption or ion collision, but also on structural properties of biomolecules. These last years, he worked on direct effects of ionizing radiation to understand the first physical and chemical steps underlying radio- and hadrontherapy. In particular, he collaborates with radiobiologists to know more about the side-effects of irradiating cartilage, through investigations on collagen mimetic peptides. One of his future projects is going towards probing conformational changes triggered by ionizing radiation, because these processes can lead to denaturation of proteins or DNA strands.
To understand the effects of ionizing radiation on biological molecular systems, it is crucial to control the experimental conditions, especially in terms of temperature and phase. Irradiation of a solution at room temperature mainly leads to the formation of free radicals from the solvent. These species then chemically react with biomolecules, leading to secondary processes such as bond cleavage, cross-linking and generally quenching of biological activity. All these indirect effects require diffusion of free radicals from the solvent to the biomolecule, which occurs at rates that decrease by several orders of magnitude from room to cryogenic temperatures. To study direct effects, frozen, lyophilized, crystallized, dried but also isolated molecules can be used. These last years, at the CIMAP lab, we have investigated the structure and stability of isolated collagen mimetic peptides and antibiotic/receptor non-covalent complexes of controlled mass and stoichiometry, by means of home-made experimental set-ups and through international collaborations. Our main findings are the following. First, the collagen triple helix exists in the gas phase, and its stability is not due to solvent. Second, interaction with one carbon ion at the Bragg-peak energy or ionizing photon in the VUV-X range mainly leads to ionization, vibrational energy deposition and intermolecular followed by intramolecular fragmentation (cf. figure 1). Radical-mediated mechanisms such as loss of neutral molecules from amino acid side chains have been found to play a big role. Our most recent studies on non-covalent complexes between the antibiotic vancomycin and its receptor suggest that ionizing photons trigger very different processes depending on pH: indeed, our results show that the protonated complex does not survive, and fragments mainly via glycosidic bond cleavage, whereas the deprotonated complex mainly loses CO2 after electron detachment. In a near future, we aim at probing the radiation-induced denaturation of biomolecular systems by tandem ion-mobility spectrometry.
Lawrence Livermore National Laboratory, USA
Keynote: Challenges and opportunities in multi-scale computational modeling of (photo-) electrocatalytic processes
Time : 10:30-11:00
Tadashi Ogitsu has his expertise in ab-initio simulations and computational spectroscopy and is interested in applying these skills and investigate on fundamental aspect of electrochemical processes relevant for energy applications such as renewable hydrogen production. He is a deputy group leader of Quantum Simulation Group at Lawrence Livermore National Laboratory and is the point of contact for DOE/EERE HydroGEN consortium (www.h2awsm.org), which is designed to facilitate sustainable hydrogen production R&D by providing highly diverse and complemental research capabilities.
Renewable energy sources, such as solar and wind energies, are intermittent in nature and show large variation in its geographical distribution, leading to necessity of scalable energy storage and re-distribution solutions. Hydrogen and hydrogen rich organic species are good candidates for such energy carrier due to its abundance of constituent elements and their high energy densities that stems from the low atomic weight of hydrogen. While methodologies for synthesizing such energy carriers already exist, further improvements are necessary for accelerating mass deployment of renewable energy.
In this talk, we will overview multi-scale aspect of (photo-)electrocatalytic processes commonly seen in water electrolysis, CO2 reduction, ammonia synthesis, and discuss about a few important concepts, time scale of individual processes, scaling relation in microscopic electrocatalytic processes and macroscopic bifurcation behavior, which are intimately connected each other. We will then discuss about the ab-initio based computational methods that can be used to obtain fundamental information such as reaction free energy profile of electrocatalytic process under realistic condition (pH, potential, ion type) with various degree of approximations. Gaining deep insights into such factors will facilitate development of the method to modulate energetics and kinetics of individual electrochemical process, and help overcoming the scaling relation that poses challenges in optimizing multi-step catalytic process and/or product selectivity. We note that such ab-initio based approach provide a way to calculate spectroscopic signature of the model system, which will enable us to validate the computational model by comparing with operando spectroscopy data.
This work was performed under the auspices of the U.S. Department of Energy under contract No. DE-AC52-07NA27344, and supported by DOE Fuel Cell Technology Office under H2@Scale program.
University of Calabria, Italy
Time : 11:20-11:50
Cesare Oliviero Rossi, Department of Chemistry and Chemical technologies, University of Calabria, Via P. Bucci, Cubo 14/D – 87036 Arcavacata, Italy
Cesare Oliviero Rossi was born in 1974 in Cosenza, Italy and he received his Degree in Chemistry, with full graduating marks and cum laude, from the University of Calabria, in 1997 and his PhD in “Chemical Sciences” at the same University in January 10, 2002, working on structural characterization of lyotropic systems. He worked in different research teams running several research projects, at University of Lund Sweden, University of Coimbra Portugal, ETH Zurich and at High Research Institute of Kazakhstan.
He was awarded the gold medal for contribution to the Road Science by High Research Institute of Kazakhstan.
Excellent research potential and an ability to actively contribute to projects goals as well as a proven publication track record, i.e. more than 100 papers in international journals. Able to interact with all researchers in a constructive, creative and professional manner. Cesare Oliviero Rossi has his expertise in the study of colloidal systems. He has been trying, in the last years, to approach the bitumen system from a different point of view, to highlight the importance of the chemistry of bitumen and its additives. He attempts to address the problem using chemical investigation techniques that have never been used in the field of asphalt binders.
This contribution a reviews the current understanding of bitumen structure and the consequences in terms of properties, with a strong emphasis on the rheological properties. The links between chemistry, structure and mechanical properties are highlighted in the framework of an updated colloidal picture of bitumen .
In particular it explores for the first time, the potentialities of additives from natural resources, i.e., non-toxic and eco-friendly biocompatible compounds, acting both as adhesion promoters and as rheological modifiers .
We found, in fact, a class of lipophilic food grade compounds to be very efficient as Multi-Functional Additives (MFA) once they were dispersed in hot bitumen solutions in small quantities. Their effect on the high temperature mechanical performance of a tested bitumen has been investigated through time cure rheological measurements and the sol-transition temperature was determined in a wide range of temperatures. The determination of the contact angle between the aggregate surface and modified bitumens, blended with increasing amounts of additives, has been also carried out.