Interactions of the Neurotoxin Vipoxin in Solution Studied by Dynamic Light Scattering

AbstractThe neurotoxin vipoxin is the lethal component of the venom of Vipera ammodytes meridionalis. It is a heterodimer of a basic toxic His-48 phospholipase A2 (PLA2) and an acidic nontoxic Gln-48 PLA2. The shape of the neurotoxin and its separated components in solution as well as their interactions with calcium, the brain phospholipid phosphatidylcholine, and two inhibitors, elaidoylamide and vitamin E, were investigated by dynamic light scattering. Calcium binding is connected with a conformational change in vipoxin observed as a change of the hydrodynamic shape from oblate ellipsoid to a shape closer to a sphere. The Ca2+-bound form of vipoxin, which is catalytically active, is more compact and symmetric than the calcium-free heterodimer. Similar changes were observed as a result of the Ca2+-binding to the two separated subunits. In the presence of aggregated phosphatidylcholine, the neurotoxic complex dissociates to subunits. It is supposed that only the toxic component binds to the substrate, and the other subunit, which plays a chaperone function, remains in solution. The inhibition of vipoxin with the synthetic inhibitor elaidoylamide and the natural compound vitamin E changes the shape of the toxin from oblate to prolate ellipsoid. The inhibited toxin is more asymmetric in comparison to the native one. Similar, but not so pronounced, effects were observed after the inhibition of the monomeric and homodimeric forms of the toxic His-48 PLA2. Circular dichroism measurements in the presence of urea, methylurea, and ethylurea indicate a strong hydrophobic stabilization of the neurotoxin. Hydrophobic interactions stabilize not only the folded regions but also the regions of intersubunit contacts

Investigation of MEMS piezoelectric transformer with PVDF thin layer

Abstract. This paper presents the results of experimental work on the thin piezoelectric polyvinylidene fluoride (PVDF) film, which is used as piezoelectric transformer. The piezoelectric PVDF film was deposited by spray deposition technique on flexible polyethylene terephthalate (PET) substrate and its thickness was measured to be 2 µm. For electrodes is deposited aluminum (Al) by thermal evaporation in vacuum. The voltage gain characteristics were measured at different frequencies. It was observed that at input frequency 1 MHz, the voltage gain characteristic started to decrease

Smart5Grid Solutions for enhanced TSO grid observability and manageability in massive RES penetration environment [version 2; peer review: 1 approved, 2 approved with reservations, 1 not approved]

This article presents the latency minimisation potential provided by the Smart5Grid Open Experimentation Platform (OEP) developed by the Horizon 2020 Smart5Grid Research and Innovation (R&I) project. It discusses the OEP performance and provides experimental data to substantiate its contribution to improving observability and manageability of distributed renewable generation in power grids. That experimental proof is delivered by two pilots running on the OEP: Demo 1 Millisecond Level Precise Distribution Generation Control, and Demo 2 Real-time Wide Area Monitoring (WAM) pilot of 5G virtual Phasor Data Concentrator v(PDC) capabilities for WAM of end-to-end electricity grids. This work reports  two Network Applications (NetApps) created to support both demos and provides experimental evidence that the OEP offers latency of comparable measure to well-established wire-bound communications in addition to availability and reliability on top of by-design flexibility, scalability and modularity, which are especially relevant to power systems with high shares of Distributed Renewable Energy Recourses (DRERs). The software and methods used for the OEP development and experimental testbeds applied to measure its latency performance in both tailored pilot demos are explained at length. The test results are presented and interpreted with a view to discussing potential contributions of the presented 5G-enabled solutions for power grid smartification in conditions of high rollout of distributed renewable generation. All pilot demos generate openly accessible data, except where specific security restrictions are applicable