Raman spectroscopy is one of the key experimental methods for the structuralanalysis of glasses, thanks to its simple application and its sensitivity to variations ofcomposition or atomic-scale order. However, the inherent disorder of the glassystructure results to broad and overlapping peaks in the spectra, rendering theirquantitative analysis a challenging task and resulting in a mostly phenomenologicalinterpretation. This drawback can be addressed by the use of modern and accuratetheoretical tools, such as ab-initio vibrational spectroscopies. In this work we havestudied three simple sodosilicate glasses, prepared using a combined classical/ab-initio approach. For these structures, we have used density functional theory (DFT) tocalculate their vibrational density of states, as well as their Raman and IR spectra.The main advantage of the DFT calculations is that the resulting spectra can bedirectly correlated with the structural models and, most importantly, the vibrationalspectrum can be decomposed into exact contributions arising from individualstructural units. In the case of the sodosilicate glasses, we have identifiedcorrelations between spectral characteristics and stoichiometry, the effect of thepresence of bridging and non-bridging oxygens, the contributions of smaller or largerSi-O-Si angles, as well as the ones arising from the presence of the so-called Q-species. These results open the way for the study of even more complex glasses andaid in the interpretation of experimental spectra.

Silicate glasses possess a central role in glass technology due to their multiple applications ranging from optical devices to the immobilization of nuclear waste. Raman spectroscopy is a key method for the investigation of their structure and the study of their properties. However, the inherent structural disorder found in glasses results in very broad and overlapping peaks in their spectra. In this context, an accurate theoretical modeling of the spectra can be proven to be invaluable in order to optimize their performance and tailor their fabrication method to match requirements for future applications. In this work, we present results on binary sodo-silicate glasses [xNa2O- (1-x)SiO2], which have been prepared by combining classical and ab-initio Molecular Dynamics. The Raman spectra (polarized and unpolarized), as well as the IR spectra, have been obtained using the Quantum Espresso package [1] in the GGA framework by employing norm-conserving pseudopotentials. Calibration runs have been carried out on the crystalline α-quartz and Na2SiO3 systems in order to optimize the choice of pseudopotentials. Concerning the glasses under study, we focused on the effect of local structural units, such as Q-species and their interconnection, alongside the role of sodium atom content in order to assign the corresponding bands. The initial results show very good agreement with previous theoretical and experimental spectra [2-5], while the ongoing decomposition relative to the exact contributions from each of the structural units of the glasses is expected to provide insight to the interpretation of the experimental spectra.References[1] P. Gianozzi et al., J. Phys.: Condens. Matter 21, 395502 (2009).[2] S. Ispas, N. Zotov, S. de Wispelaere, W. Kob, J. Non-Cryst. Solids 351, 1144 (2005).[3] N. Zotov, H. Keppler, Phys. Chem. Minerals 25, 259 (1998).[4] B. Hehlen, D.R. Neuville, J. Phys. Chem. B 119, 4093 (2015).[5] B.O. Mysen, J.D. Frantz, Contrib. Mineral. Petrol. 117, 1 (1994).

Gene expression and cellular physiology are deeply connected. In this talk I present a few ideas on how I imagine to relate those processes with a mathematical model.

Proteins are the basis of cellular functions, yet key parameters regulating protein synthesis remain elusive. Understanding the fine mechanisms of this regulation is a major goal of molecular and systems biology, and this knowledge will support many “synthetic biological” applications.We have the ambitious goal of providing a comprehensive modeling framework of one of the last steps of protein synthesis, namely mRNA translation. In this presentation I will focus on translation initiation and elongation, which relative role is highly debated in the literature (is the ribosome recruitment or the codon bias determining the expression of a gene?). Here I will explain how the transcript efficiency can be dictated by ribosome abundances, codon usage and transcript length. We propose an approach based on the standard exclusion process, a prototypic lattice gas model. This mathematical framework considers long-range dynamical effects often neglected in standard translation models.The model is compared to experimental ribosome density and gene expression data, which are well reproduced qualitatively and quantitatively. The proposed mathematical framework also describes the origins of the well-known and yet not understood relation between transcript efficiency and its length. We also speculate on the role of transcript length in the competition for ribosomes among different mRNAs.

Hydrogen is very likely the ultimate future of the energetic economy of the world: it is ubiquitous in the en-vironment, it can be sustainably produced, and it holds the highest energy per unit mass of any fuel (except nuclear). If combusted, it produces only water. Therefore hydrogen, when used as energy vector, enters the natural water cycle of the Earth, with no impact on the planet’s climate. Today the major issue of the wide-spread hydrogen use is its low mass and low volume storage, as the energy density of hydrogen gas is low. Physisorption in nanoporous materials seems to be the most promising way of storage, as it does not release much energy during adsorption and in principle do not require the energy input when hydrogen is released.In this paper we will present the Grand Canonical Monte Carlo simulations of hydrogen adsorption in slit-shaped carbon nanopores. Our calculations confirm the very controversial experimental results [1-3] showing that under confinement the density of hydrogen film adsorbed on the carbon wall exceeds that of the bulk liquid at low temperature and approaches that of solid hydrogen at extreme pressures. The densification of hydrogen is restricted to the layer in direct contact with the adsorbent, and does not depend significantly on the pore size (at least for the pores of the width from 0.6 to 3.0 nm) nor on the temperature (for 77 K< T < 180 K).The simulations are confronted with the experimental isotherms of hydrogen adsorption in KOH - activat-ed nanoporous carbons [3] obtained from biomass waste [4]. The numerical and experimental results are coherent and prove that the interaction between hydrogen molecules and carbon surface is strong enough to produce adsorbed layer with solid hydrogen density.We also show that the gas confined in nanopores is structured, and its density is not uniform across the whole pore volume (Fig.1). In addition, the gas density depends on the pore size (Fig.2). This fact, never re-ported before, should be taken into account when the total (excess) amount stored is estimated from the excess (total) values.