Progress in thermonuclear fusion energy research based on deuterium plasmas magnetically confi ned in toroidal tokamak devices requires the development of effi cient current drive methods. Previous experiments have shown that plasma current can be driven effectively by externally launched radio frequency power coupled to lower hybrid plasma waves. However, at the high plasma densities required for fusion power plants, the coupled radio frequency power does not penetrate into the plasma core, possibly because of strong wave interactions with the plasma edge. Here we show experiments performed on FTU (Frascati Tokamak Upgrade) based on theoretical predictions that nonlinear interactions diminish when the peripheral plasma electron temperature is high, allowing signifi cant wave penetration at high density. The results show that the coupled radio frequency power can penetrate into high-density plasmas due to weaker plasma edge effects, thus extending the effective range of lower hybrid current drive towards the domain relevant for fusion reactors.
In the context of drug−receptor binding affinity calculations using molecular dynamics techniques, we implemented a combination of Hamiltonian replica exchange (HREM) and a novel nonequilibrium alchemical methodology, called virtual double-system single-box, with increased accuracy, precision, and efficiency with respect to the standard nonequilibrium approaches. The method has been applied for the determination of absolute binding free energies of 16 newly designed noncovalent ligands of the main protease (3CL pro ) of SARS-CoV-2. The core structures of 3CL pro ligands were previously identified using a multimodal structure-based ligand design in combination with docking techniques. The calculated binding free energies for four additional ligands with known activity (either for SARS-CoV or SARS-CoV-2 main protease) are also reported. The nature of binding in the 3CL pro active site and the involved residues besides the CYS−HYS catalytic dyad have been thoroughly characterized by enhanced sampling simulations of the bound state. We have identified several noncongeneric compounds with predicted low micromolar activity for 3CL pro inhibition, which may constitute possible lead compounds for the development of antiviral agents in Covid-19 treatment.
ENEA is the Italian National Agency for New Technologies, Energy and Sustainable Economic Development. ENEA operates in many sectors among which the most important are: energy technologies, materials physics, life sciences and climate. In the framework of its institutional mission, the ICT Division provides computing and storage resources integrated into ENEAGRID/CRESCO, an infrastructure distributed over 6 sites, whose main facilities are the HPC CRESCO clusters. The bulk of all storage is based on IBM Spectrum Scale (GPFS) since many years. The access to data, even over WAN, is managed by GPFS clusters. In May 2018 the new cluster CRESCO6 was inaugurated. CRESCO6, a 1.4 Pflops based on Intel Xeon X86_64 SkyLake CPU ranked at 420 th of TOP 500 Nov.2018 list. While the interconnection of CRESCO6 is based on Intel Omni-Path (OPA) (100 Gbps), the previous CRESCO4 and CRESCO5 clusters have a network based on InfniBand QDR Truescale fabric (40 Gbps). Hence, in order to provides storage to all CRESCO clusters a GPFS multifabric layout has been implemented after dedicated tests. The work describes the ENEAGRID/CRESCO infrastructure and in particular the solution adopted to implement the GPFS multifabric.
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