Impact of externally applied 3D fields on plasma rotation and correlation to particle losses

El modo de alto confinamiento (H-mode) está considerado como el modo de operación óptimo para futuros dispositivos de fusión nuclear. El H-mode viene acompañado de inestabilidades que provocan la expulsión de partículas y energía, y deterioran el confinamiento del plasma. Aunque dichas inestabilidades son tolerables en los dispositivos actuales, el desarrollo de t´ecnicas para su control es fundamental de cara a garantizar la integridad de futuros reactores. La aplicación de perturbaciones magnéticas externas es una de las herramientas más extendidas para la mitigación e incluso completa supresión de dichas inestabilidades. Estas perturbaciones alteran la simetría del campo magnético que confina al plasma. La respuesta del plasma a dichas perturbaciones es una línea de investigación muy activa actualmente. El objetivo de este trabajo es el estudio detallado de dos descargas de baja colisionalidad, llevadas a cabo en el tokamak ASDEX Upgrade. Durante estas descargas se aplican perturbaciones magnéticas externas para estudiar la respuesta del plasma. El estudio está centrado en el análisis de la evolución temporal acoplada de la rotación toroidal de las impurezas, pérdida de iones rápidos y densidad. Los resultados obtenidos revelan fuertes correlaciones entre estos para´metros. Las interdependencias entre las magnitudes dependen de (1) la caracterización de la población de iones rápidos sujeta a pérdidas y (2) la posición radial en la que se miden rotación y densidad. Se han observado fuertes cambios en el patrón de correlaciones asociados a las diferencias en las órbitas de los iones rápidos; y la intensificación de la correlación hacia el borde del plasma. Bajo determinadas circunstancias, se produce un cambio en el sentido de giro de la rotación toroidal de las impurezas en el borde del plasma, i.e. las impurezas en el borde y en el centro giran en sentido contrario. Ello también conlleva un cambio en el patrón de la correlación.The high-confinement mode (H-mode) is considered to be the baseline operational scenario for future nuclear fusion devices. The H-mode is accompanied by instabilities that cause cyclic ejection of particles and energy, thus deteriorating the confinement of the plasma. Although these instabilities are tolerable in current experiments, the development of techniques for their control is crucial to guarantee the integrity of future devices. The application of external 3D magnetic fields is one of the most efficient techniques to achieve the mitigation and even full suppression of these instabilities. These magnetic perturbations break the symmetry of the magnetic field. The impact of the perturbations on the plasma is currently a very active research line. The objective of this thesis is a detailed analysis of two low collisionality discharges, which were carried out in the ASDEX Upgrade tokamak experiment. In these two discharges static magnetic perturbations were applied to study plasma response. The study is focused on the observation of the coupled evolution of the toroidal impurity rotation, fast-ion losses and electron density. The results reveal strong correlations between the parameters. The interdependencies between the parameters depend on (1) the type of fast-ion population which is subject to losses and (2) the radial position at which rotation and density are measured. A strong change in the correlation pattern is associated with changes in the orbit topology of the fast-ions. The correlation towards the plasma edge becomes more intense. Under certain circumstances, a change in the correlation pattern at the edge is connected to an impurity toroidal rotation reversal, i.e. a spin-up of the impurities in opposite direction to the plasma core.Universidad de Sevilla. Máster Universitario en Física Nuclea

Exploring Highly Conserved Regions of SARS-CoV-2 Spike S2 Subunit as Targets for Fusion Inhibition Using Chimeric Proteins

Since the beginning of the COVID-19 pandemic, considerable efforts have been made to develop protective vaccines against SARS-CoV-2 infection. However, immunity tends to decline within a few months, and new virus variants are emerging with increased transmissibility and capacity to evade natural or vaccine-acquired immunity. Therefore, new robust strategies are needed to combat SARS-CoV-2 infection. The viral spike composed of S1 and S2 subunits mediates viral attachment and membrane fusion to infect the host cell. In this process, interaction between the highly conserved heptad repeat 1 and 2 regions (HR1 and HR2) of S2 is crucial and for this reason; these regions are promising targets to fight SARS-CoV-2. Here, we describe the design and characterization of chimeric proteins that structurally imitate the S2 HR1 region in a trimeric coiled-coil conformation. We biophysically characterized the proteins and determined their capacity to bind the HR2 region, as well as their inhibitory activity of SARS-CoV-2 infection in vitro. HR1 mimetic proteins showed conformational heterogeneity and a propensity to form oligomers. Moreover, their structure is composed of subdomains with varied stability. Interestingly, the full HR1 proteins showed high affinity for HR2-derived peptides and SARS-CoV-2 inhibitory activity, whereas smaller proteins mimicking HR1 subdomains had a decreased affinity for their complementary HR2 region and did not inhibit the virus. The results provide insight into effective strategies to create mimetic proteins with broad inhibitory activity and therapeutic potential against SARS-CoV-2.Junta de AndaluciaSpain's State Research Agency CV20.26565 ERDF/ESF PID2019.107515RB.C21ANRSFrench National Research Agency (ANR) French National Research Agency (ANR)EHVA ANR-10-LABX-77 68103

Analysis of supercritical carbon dioxide Brayton cycles for a helium-cooled pebble bed blanket DEMO-like fusion power plant

Article number 112860Nuclear fusion is expected to be a clean and almost-unlimited power source in the near future. The first net power demonstration plant (DEMO) is planned to start operation in 2050. The supercritical carbon dioxide (S-CO2) Brayton cycle is an excellent candidate for integration with a fusion power plant, such as DEMO, because of its high efficiency at intermediate temperatures and low interaction of coolant with tritium. This work analyses a set of S-CO2 Brayton cycle layouts for its integration in a DEMO-like fusion power plant, considering the specific requirements and heat availability characteristics. A framework has been developed to integrate the PROCESS code and the numerical solver EES to study the thermal and economic aspects of integrating the different S-CO2 cycle layouts. In total, 14 layouts have been studied and grouped into a more conservative (DEMO1, pulsed operation) and more advanced (DEMO2, steady-state operation) fusion reactors. The PROCESS code has been used to obtain the DEMO 2018 Baseline, which defines the available power from each heat source and their boundary conditions. This code has also been used to assess the cost of the optimal layout. Thermal storage has been added to the DEMO1 scenario to avoid standby times that could negatively affect the cycle equipment lifetime and efficiency. Besides, these boundary conditions have been extended to account for possible technical improvements by the time of its construction in the DEMO2 scenario. A sensitivity analysis of the most characteristic parameters of the cycles shows a strong dependence on the turbine inlet temperature for all layouts, which is constrained by the reactor material limits. The cycle efficiency (electric power produced before consumptions non-related to the cycle) has been selected as the figure of merit for the optimisation. The results show a 38% cycle efficiency for DEMO1 and 56% for DEMO2 scenarios. These efficiencies drop to 20% and 38% values, respectively, when the reactor and cooling loop power consumptions are considered. These values are obtained for current fusion reactor conceptual designs. The economic analysis shows the economic viability of DEMO2 scenarios.Ministerio de Ciencia e Innovación (España) FPU17/06273Horizonte 2020 (Unión Europea) 708257Horizonte 2020 (Unión Europea) 80516

Novel chimeric proteins mimicking SARS-CoV-2 spike epitopes with broad inhibitory activity.

SARS-CoV-2 spike (S) protein mediates virus attachment to the cells and fusion between viral and cell membranes. Membrane fusion is driven by mutual interaction between the highly conserved heptad-repeat regions 1 and 2 (HR1 and HR2) of the S2 subunit of the spike. For this reason, these S2 regions are interesting therapeutic targets for COVID-19. Although HR1 and HR2 have been described as transiently exposed during the fusion process, no significant antibody responses against these S2 regions have been reported. Here we designed chimeric proteins that imitate highly stable HR1 helical trimers and strongly bind to HR2. The proteins have broad inhibitory activity against WT B.1 and BA.1 viruses. Sera from COVID-19 convalescent donors showed significant levels of reactive antibodies (IgG and IgA) against the HR1 mimetic proteins, whereas these antibody responses were absent in sera from uninfected donors. Moreover, both inhibitory activity and antigenicity of the proteins correlate positively with their structural stability but not with the number of amino acid changes in their HR1 sequences, indicating a conformational and conserved nature of the involved epitopes. Our results reveal previously undetected spike epitopes that may guide the design of new robust COVID-19 vaccines and therapies.This work was supported by grants CV20.26565 from the Consejería de Economía y Conocimiento, Junta de Andalucía (Spain), PID2019.107515RB.C21 from the Spanish State Research Agency (SRA/10.13039/501100011033), and co-funded by ERDF/ESF, “A way to make Europe”/“Investing in your future. The work performed in C.M.’s laboratory was supported by grants from ANRS (Agence Nationale de Recherches sur le SIDA et les h´epatites virales), the Investissements d’Avenir program managed by the ANR under reference ANR-10-LABX-77 and EHVA (No. 681032, Horizon 2020). Work in S.B.’s laboratory was supported by grants from the Agence Nationale de la Recherche (ANR) (ANR-11-LABX-0070_TRANSPLANTEX), the INSERM (UMR_S1109), the Institut Universitaire de France (IUF), all the University of Strasbourg (IDEX UNISTRA), the European Regional Development Fund (European Union) INTERREG V program (project no. 3.2 TRIDIAG) and MSD-Avenir grant AUTOGEN

Dynamics of the pedestal transport during edge localized mode cycles at ASDEX Upgrade

The dynamic behaviour of the ion and electron energy, particle and momentum transport measured during type-I edge localized mode (ELM) cycles at ASDEX Upgrade is presented. Fast measurements of the ion and electron temperature profiles revelead that the ion and electron energy transport recover on different timescales, with the electrons recovering on a slower timescale (Cavedon et al 2017 Plasma Phys. Control. Fusion 59 105007). The dominant mechanism for the additional energy transport in the electron channel that could cause the delay in the electron temperature gradient (VTe) recovery is attributed to the depletion of energy caused by the ELM. The local sources and sinks for the electron channel in the steep gradient region are much smaller compared to the energy flux arriving from the pedestal top, indicating that the core plasma may dictate the local dynamics of the VTe recovery during the ELM cycle. A model for the edge momentum transport based on toroidal torque balance that takes into account the existence of poloidal impurity asymmetries has been developed. The analysis of the profile evolution during the ELM cycle shows that the model captures the dynamics of the rotation both before the ELM crash and during the recovery phase.European Commission (Euratom) Grant agreement No. 633053H2020 Marie-Sklodowska Curie programme (grant agreement No. 708257)European Union’s Horizon 2020 (grant agreement No. 805162

Probing vulnerability of the gp41 C-terminal heptad repeat as target for miniprotein HIV inhibitors

One of the therapeutic strategies in HIV neutralization is blocking membrane fusion. In this process, tight interaction between the N-terminal and C-terminal heptad-repeat (NHR and CHR) regions of gp41 is essential to promote membranes apposition and merging. We have previously developed single-chain proteins (named covNHR) that accurately mimic the complete gp41 NHR region in its trimeric conformation. They tightly bind CHR-derived peptides and show a potent and broad HIV inhibitory activity in vitro. However, the extremely high binding affinity (sub-picomolar) is not in consonance with their inhibitory activity (nanomolar), likely due to partial or temporal accessibility of their target in the virus. Here, we have designed and characterized two single-chain covNHR miniproteins each encompassing one of the two halves of the NHR region and containing two of the four sub-pockets of the NHR crevice. The two miniproteins fold as trimeric helical bundles as expected but while the C-terminal covNHR (covNHR-C) miniprotein is highly stable, the N-terminal counterpart (covNHR-N) shows only marginal stability that could be improved by engineering an internal disulfide bond. Both miniproteins bind their respective complementary CHR peptides with moderate (micromolar) affinity. Moreover, the covNHR-N miniproteins can access their target in the context of trimeric native envelope proteins and show significant inhibitory activity for several HIV pseudoviruses. In contrast, covNHR-C cannot bind its target sequence and neither inhibits HIV, indicating a higher vulnerability of C-terminal part of CHR. These results may guide the development of novel HIV inhibitors targeting the gp41 CHR region.Spanish Ministry of Economy and Competitiveness (grant: BIO2016-76640-R), ANRS and the Vaccine Research Institute for the Investissements d'Avenir program to C.M. and by the European Fund for Research and Development from the European Union.Departamento de Química Física, Facultad de Ciencias, Universidad de Granada. Grupo FQM-171 "Biofísica y Biotecnología Molecular

Experimental study of the impact of ion orbit losses on the edge radial electric field at the ASDEX Upgrade tokamak

Spanish Ministry of Science, Innovation and Universities (grant FPU17/06273)EUROfusion Consortium 63305

Upgrade of the edge Charge Exchange Recombination Spectroscopy system at the High Field Side of ASDEX Upgrade

The upgrade of the high field side (HFS) edge charge exchange recombination spectroscopy (CXRS) system of ASDEX Upgrade is presented. This diagnostic provides temperature, rotation and radiance measurements of impurity species by taking advantage of the gas puff based CXRS technique (GP-CXRS). The system is formed by a fast piezoelectric valve, that injects thermal neutrals into the plasma, and two optical heads. The localized gas injection together with properly aligned lines of sights (LOS) lead to a high spatial resolution of 5–19 mm. Fast gas puff modulation allows a precise subtraction of the passive part of the signal. The existing poloidal optical head has been replaced with a new one to increase the radial resolution. The number of lines of sight (LOS) of the poloidal optical head has been increased from 8 to 16 covering around 7 cm of the plasma edge at the HFS. The same radial range is also viewed by a toroidal optical head. The neutral deposition, needed to calculate the impurity density profile, has been modelled using the FIDASIM code. A realistic gas puff geometry has been implemented in the code. The first measurements of impurity temperature, rotation and radiance utilizing the upgraded diagnostic are presented.Universidad de Sevilla PPITUS 2017EUROfusion Consortium 633053H2020 Marie-Skłodowska Curie programme (Grant No. 708257)Spanish Ministry of Economy and Competitiveness (Grant No. FJCI-201422139

Teaching methodology in European universities: Erasmus student´s perception

El objetivo de este estudio fue identificar la metodología docente utilizada en el Espacio Europeo de Educación Superior (EEES). 240 estudiantes ERASMUS, de diferentes países y áreas de conocimiento, evaluaron, mediante un cuestionario (vía web), la frecuencia de utilización de distintas: (a) Modalidades Organizativas; (b) Métodos de Enseñanza; (c) Estrategias de Evaluación; y (d) Tecnologías de la Información y la Comunicación (TIC). Las respuestas mostraron una notable dispersión y un primer análisis reveló la inexistencia de una única metodología docente en el EEES, típica de Bolonia (Proyecto Tuning). Un análisis más pormenorizado reveló que esa metodología parece estar centrada más en la Teoría (e.g., Método Expositivo), seguida por la Práctica (e.g., Seminarios y Clases Prácticas), que en los Proyectos (e.g., Estudio y Trabajo, tanto grupal como autónomo, Método del Aprendizaje Orientado a Proyectos), lo que parecería indicar la falta de afianzamiento del pretendido cambio de paradigma desde la enseñanza al aprendizaje.This study aims to identify the educational methodology used in the European Space of Higher Education (ESHE). 207 Erasmus students, from different countries and fields of study, assessed, via an on-line questionnaire, the frequency of use of different Organizational and Teaching methods, Evaluation strategies and IT. The answers showed a significant variety and a first analysis revealed that no unique teaching methodology existed in the ESHE, typical of Bologna(Tuning Project). A more detailed analysis showed that this methodology appears to be focused on theory (e.g., Presentation method), followed by Practice (e.g., Seminars and Practical’s), rather than on Projects (e.g., Group and autonomous studies, Project-based learning), which would appears to indicate a lack of consolidation of the intended paradigm from teaching to learning.Grupo FORCE (HUM-386). Departamento de Didáctica y Organización Escolar de la Universidad de Granada

Poloidal impurity asymmetry studies using the upgraded high field side edge CXRS diagnostic at ASDEX Upgrade

EUROfusion Consortium 63305