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Advanced three-dimensional X-ray imaging unravels structural development of the human thymus compartments
Get PDFBackground: The thymus, responsible for T cell-mediated adaptive immune system, has a structural and functional complexity that is not yet fully understood. Until now, thymic anatomy has been studied using histological thin sections or confocal microscopy 3D reconstruction, necessarily for limited volumes. Methods: We used Phase Contrast X-Ray Computed Tomography to address the lack of whole-organ volumetric information on the microarchitecture of its structural components. We scanned 15 human thymi (9 foetal and 6 postnatal) with synchrotron radiation, and repeated scans using a conventional laboratory x-ray system. We used histology, immunofluorescence and flow cytometry to validate the x-ray findings. Results: Application to human thymi at pre- and post-natal stages allowed reliable tracking and quantification of the evolution of parameters such as size and distribution of Hassall’s Bodies and medulla-to-cortex ratio, whose changes reflect adaptation of thymic activity. We show that Hassall’s bodies can occupy 25% of the medulla volume, indicating they should be considered a third thymic compartment with possible implications on their role. Moreover, we demonstrate compatible results can be obtained with standard laboratory-based x-ray equipment, making this research tool accessible to a wider community. Conclusions: Our study allows overcoming the resolution and/or volumetric limitations of existing approaches for the study of thymic disfunction in congenital and acquired disorders affecting the adaptive immune system
National programme for the reliability of ionizing radiation measurements based on inter-laboratory comparisons (ILCs): ILC n°2 ‘radiopharmaceutical activities’
Get PDFA national Inter-Laboratory Comparisons (ILCs) programme was organized in Italy in 2022 by the Italian National Institute of Ionizing Radiation Metrology (INMRI), belonging to ENEA (Italian National Agency for New Technologies, Energy and Sustainable Economic Development), under the auspices of the Ministry of Enterprises and Made in Italy (Mimit ex MiSe). Within this ILCs programme, six inter-laboratory comparisons were organized, including the ILC-2 which focused on activity measurements carried out with radionuclide calibrators commonly used in the nuclear medicine departments of the participants. The focus was on three short-lived radionuclides - 99mTc, 18F, 177Lu - commonly employed in nuclear medicine for both diagnostic and therapeutic purposes. All presented results were compared with the reference values provided by ENEA-INMRI to ensure the traceability of measurements to the national primary activity standards. The observed deviation from the reference values of the measured activity were mainly within ± 10% (100% for 18F, 91.7% for 99mTc, 100% for 177Lu). The En statistical estimator was used to assess the participants’ ability to estimate uncertainty in the provided activity values. The obtained values revealed that, in certain instances, the involved laboratories did not achieve the correct results for En (with failure rates of 22.7%, 16.7%, 12.5% for 18F, 99mTc, 177Lu, respectively), despite deviations from the reference values falling within the ± 10%. The aim of ILC-2 was to harmonize the activity measurements in the country within the field of nuclear medicine for the specific radionuclides studied and enhance the measurement capabilities of the participants
Use of distributed temperature sensing (DTS) coupled to ground source heat exchangers for geological thermo-stratigraphic correlation
Get PDFThe thermal characterisation of a geosonde field, consisting of four boreholes at the ENEA-Casaccia Research Centre (Rome, Italy), was carried out by processing the temperature values measured by DTS (Distributed Temperature Sensing) fibre optics positioned vertically in each well. By correlating the vertical temperature profiles, it was possible to estimate the thermal conductivity of each stratigraphic level and the contribution of the groundwater on the heat exchange between ground and geothermal probes. The theoretical model has been confirmed by the experimental data obtained through direct measurement of thermal conductivity on soil/rock samples collected at different depths. In the first 10 m of depth, temperature variations are influenced by seasonal climatic fluctuations, the amplitude of which decreases with depth, to regularise and assume a linear trend, compatible with the movement of groundwater. The work carried out has shown that the area investigated is affected by the upwelling of hydrothermal fluids from the deep aquifer, which infiltrate the fractured lavas reaching the most superficial layers of the subsurface. The results of this research could be useful for estimating the geothermal potential of the areas within the ‘Cesano geothermal field’, whose lithotypes belong to the Sabatini volcanic province
Long-pulse high heat flux testing of tungsten monoblock target mock-ups for investigation of creep fatigue interaction
Get PDFDivertor components for ITER and even beyond will be subjected to cyclic steady state heat loads with a duration of several minutes to hours, repeatedly occurring slow transients during reattachment or ramp-up and down, as well as heat loads during ELMs applying a combination of low cycle fatigue and creep as well as high cycle fatigue via thermal shock loads. While for the qualification of components the duration of the fatigue cycles up to now has been kept small, i.e., close to the required time to reach thermal saturation which is 10 s for typical divertor components, creep in these components has not yet been assessed. In this study divertor tungsten monoblock mock-up manufactured via hot radial pressing in the ITER-like geometry consisting of 4 monoblocks and quality checked via ultrasonic testing are exposed to high heat flux loads in the electron beam facility JUDITH 2 using a high temperature cooling circuit with controlled water chemistry. Thereby, cyclic loads up to 1000 cycles with a duration of 10 to 600 s and a power density of 20 MW/m2 were applied, representing strike point loading conditions in DEMO during strike point sweeping scenarios. Each of the tungsten monoblocks is loaded individually providing the possibility to study different scenarios on one single mock-up. The aim is to assess the performance and degradation of performance due to the applied loads, which is supported by characterization via metallography, profilometry, SEM and hardness testing after the high heat flux tests
Overview of recent experimental results on the EAST Tokamak
Get PDFSince the last IAEA-FEC in 2021, significant progress on the development of long pulse steady state scenario and its related key physics and technologies have been achieved, including the reproducible 403 s long-pulse steady-state H-mode plasma with pure radio frequency (RF) power heating. A thousand-second time scale (∼1056 s) fully non-inductive plasma with high injected energy up to 1.73 GJ has also been achieved. The EAST operational regime of high βP has been significantly extended (H98y2 > 1.3, βP ∼ 4.0, βN ∼ 2.4 and ne/nGW ∼ 1.0) using RF and neutral beam injection (NBI). The full edge localized mode suppression using the n = 4 resonant magnetic perturbations has been achieved in ITER-like standard type-I ELMy H-mode plasmas with q95 ≈ 3.1 on EAST, extrapolating favorably to the ITER baseline scenario. The sustained large ELM control and stable partial detachment have been achieved with Ne seeding. The underlying physics of plasma-beta effect for error field penetration, where toroidal effect dominates, is disclosed by comparing the results in cylindrical theory and MARS-Q simulation in EAST. Breakdown and plasma initiation at low toroidal electric fields (<0.3 V m−1) with EC pre-ionization is developed. A beneficial role on the lower hybrid wave injection to control the tungsten concentration in the NBI discharge is observed for the first time in EAST suggesting a potential way toward steady-state H-mode NBI operation
Accessibility Measures to Evaluate Public Transport Competitiveness: The Case of Rome and Turin
Get PDFHighlights: What are the main findings? Results show that private car indexes for mobility, competitiveness and accessibility are higherthan those of public transport. Significant variability in performance indicators among city areas are identified, indicatinginequalities in social and environmental sustainability in urban systems. What are the implications of the main findings? Policy actions need to be tailored to the specific area of the city based on quantitative evidence. Strategies need to consider multiple dimensions to effectively support the use of public transport. The transport sector worldwide relies heavily on oil products, and private cars account for the largest share of passenger mobility in several countries. Public transport could represent an interesting alternative under many perspectives, including a decrease in traffic, pollutants, and climate emissions. However, for public transport to succeed, it should be attractive for final users, representing a viable alternative to private mobility. In this work, we analyse the spatial distribution of public transport service provision within two metropolitan cities, considering the three key dimensions of mobility, competitiveness, and accessibility of public transport. The results show that private car performs better than public transport in all scopes considered, and that performance indicators are highly variable among city areas, indicating inequalities in social and environmental sustainability in urban systems. The outcomes of the analysis provide interesting insights for policy makers and researchers that deal with similar topics, and can also be extended to other cities and countries
Application of the Analytic Hierarchy Process (AHP) method to identify the most suitable approach for managing irradiated graphite
Get PDFScientific literature studies irradiated graphite treatment. Research also covers graphite conditioning and its long-term behavior under disposal conditions. The European Commission's CARBOWASTE project, titled “Treatment and disposal of irradiated graphite and other carbonaceous waste”, is a key reference for state-of-the-art studies on alternative solutions. It identified 24 strategic options for managing irradiated graphite throughout its complete life cycle. The methodology proposed in this paper entails the application of the Analytic Hierarchy Process (AHP) method to rank the 24 options, placing particular emphasis on the weighting of seven criteria for selecting management options for the irradiated graphite. The highest weights were assigned by experts to ‘environment and public safety' (28.05 %) and ‘worker safety' (26.16 %). The objective is to develop a standardized approach enabling waste management companies to identify the most appropriate management option, considering structural and legislative constraints in their operating country. Examining the study findings, option 19 “In-situ entombment” stands out as the best choice in both the CARBOWASTE project and the proposed methodology. Thus, this methodology could assist hypothetical entities in examining management options for irradiated graphite, with the aim of identifying the optimal solution for graphite waste disposal
Overcoming the Open-Circuit Voltage Losses in Narrow Bandgap Perovskites for All-Perovskite Tandem Solar Cells
Get PDFNarrow-bandgap (NBG) perovskite solar cells based on tin-lead mixed perovskite absorbers suffer from significant open-circuit voltage (VOC) losses due primarily to a high defect density and charge carrier recombination at the device interfaces. In this study, the VOC losses in NBG perovskite single junction cells (Eg = 1.21 eV) are addressed. The optimized NBG subcell is then used to fabricate highly efficient all-perovskite tandem solar cells (TSCs). The improvement in the VOC is achieved via the addition of a thin poly(triarylamine) interlayer between the poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS)-based hole transport layer (HTL) and the NBG perovskite. The optimal bilayer HTL results in a champion power conversion efficiency (PCE) of 20.3%, compared to 17.8% of the PEDOT:PSS-based control device. The VOC improvement of the single-junction NBG cell is also successfully transferred to all-perovskite TSC, resulting in a high VOC of 2.00 V and a PCE of 25.1%
Design progress of DTT divertor fixation system
Get PDFOne of the main challenges for the construction of DEMO, the first fusion demonstration reactor, is the power exhaust issue. To deal with it, EUROfusion has undertaken the construction of DTT (Divertor Tokamak Test) facility which will be held in Frascati, Italy. It aims to test various divertor models which can be integrated and used under different plasma confinement configurations. The current design of DTT embed 54 divertor cassettes which must be anchored to the vacuum vessel using suitable fixation systems. This paper deals with the initial monotonic load assessment of the fixation system of the Fixation System which must ensure compliance with multiple design requirements. The Remote Handling compatibility is one of the most demanding, since it includes a preloading phase of the divertor necessary to mitigate the shaking of the cassette due to dynamic forces. Moreover, the system must withstand the conspicuous loads acting on the Divertor due to the full or partial loss of plasma confinement (Disruptive Events). Structural verifications through Finite Element Method (FEM) have been performed on the Divertor-Fixation System, considering a set of load combinations, with particular focus on the most demanding case related to Fast-transient Vertical Disruption Event-downward