3D-QSAR/CoMFA Models as a Tool for Biocatalysis and Protein Engineering

The x-ray structure of an enzyme is taken into account, when available, as the reference model to explain catalytic activity and selectivity. Unfortunately, in most of the cases the structure is available only as apostructure, i.e. without the substrate bound to the active site, and it is strange to find many different enzyme-substrate complexes of a specific enzyme as crystals. Moreover this structure is not the "real" structure of the protein during catalysis as the crystal is stationary. In this paper we propose the use of CoMFA models to evaluate the differences betweenthe crystal and the real structure of the enzyme under reaction conditions. In addition to the stationary nature of a crystal, the experimental limitations of crystallographic techniques to obtain crystals in a fast and reliable manner, give a chance to the creation of CoMFA models by evaluating the easy to obtain catalytic properties of enzyme variants to provide information about the structural changes produced by the mutations. By means of the evaluation of different structures as substrates CoMFA models will not only provide information about the structure of the enzyme, but also about the flexibility and potential conformational changes of the substrate binding site

Paraconductivity of granular Al films at high reduced temperatures and magnetic fields

International audienceThe electrical conductivity induced near the superconducting transition by thermal fluctuations was measured in different granular aluminum films. The seemingly anomalous behavior at high reduced temperatures and magnetic fields is explained by taking into account a total-energy cutoff in the superconducting fluctuation spectrum in both the direct (Aslamazov-Larkin) and the indirect (anomalous Maki-Thompson) contributions to the fluctuation effects. The analysis allowed a reliable determination of the coherence length amplitudes, which resulted to be much larger (20-48 nm) than the grains size (5-10 nm). This suggests that the grains are strongly Josephson-coupled, while the T c value is still as high as twice the bulk value. These results could contribute to identifying the mechanisms enhancing T c in these materials

Railway rolling noise mitigation through optimal track design

[EN] The main goal of the present work lies in the identification of the railway track properties that influence acoustic radiation, as well as in the analysis of these properties for the reduction of sound levels. This is achieved through a dynamic model of the railway wheel and track that allows the study of rolling noise, produced as a result of the wheel/rail interaction. Once the vibrational response of the railway components is determined, the sound power radiated by them is evaluated. The influence of the track properties on the sound radiation is determined by analysing the acoustic power results of different track configurations. From the results obtained, a number of guidelines are presented for noise mitigation of the involved railway elements. Between the worst and the best track design, there are differences of approximately 7.4 dB(A) in the radiation considering the wheel, rail and sleeper noise.The authors gratefully acknowledge the financial support of Agencia Estatal de Investigación and European Regional Development Fund (grant FPU18/03999, project TRA2017-84701-R and project PID2020-112886RA-I00)Andrés Ruiz, V.; Martínez Casas, J.; Carballeira Morado, J.; Denia Guzmán, F.; Thompson, DJ. (2022). Railway rolling noise mitigation through optimal track design. En Proceedings of the YIC 2021 - VI ECCOMAS Young Investigators Conference. Editorial Universitat Politècnica de València. 313-319. https://doi.org/10.4995/YIC2021.2021.12583OCS31331