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A Functional Human Glycogen Debranching Enzyme Encoded by a Synthetic Gene: Its Implications for Glycogen Storage Disease Type III Management
No full textBackground: Glycogen Storage Disease type III (GSD III) is a metabolic disorder resulting from a deficiency of the Glycogen Debranching Enzyme (GDE), a large monomeric protein (approximately 170 kDa) with cytoplasmic localization and two distinct enzymatic activities: 4-α-glucantransferase and amylo-α-1,6-glucosidase. Mutations in the Agl gene, with consequent deficiency in GDE, lead to the accumulation of abnormal/toxic glycogen with shorter chains (phosphorylase limit dextrin, PLD) in skeletal and/or heart muscle and/or in the liver. Currently, there is no targeted therapy, and available treatments are symptomatic, relying on specific diets. Methods: Enzyme Replacement Therapy (ERT) might represent a potential therapeutic strategy for GSD III. Moreover, the single-gene nature of GSD III, the subcellular localization of GDE, and the type of affected tissues represent ideal conditions for exploring gene therapy approaches. Toward this direction, we designed a synthetic, codon-optimized cDNA encoding the human GDE. Results: This gene yielded high amounts of soluble, enzymatically active protein in Escherichia coli. Moreover, when transfected in Human Embryonic Kidney cells (HEK-293), it successfully encoded a functional GDE. Conclusion: These results suggest that our gene or protein might complement the missing function in GSD III patients, opening the door to further exploration of therapeutic approaches for this disease
The Passive Heat Removal Facility: Testing and Demonstrating an Innovative Decay Heat Removal System
No full textInnovative reactor concepts are being studied by several research institutions and private entities for their role against climate change and energy poverty. The Generation IV International Forum, committed for more than 20 years in support of advanced reactors, has drawn up a series of objectives for the new class of nuclear plants, among which is an improvement in safety and economy through passive safety systems for the removal of decay heat. One of the most studied technologies is the lead fast reactor (LFR), whose coolant has a high boiling point, excellent shielding capabilities, and good heat transfer in forced and natural circulation, as well as neutron properties suitable for a hard spectrum. These allow for designing systems with high simplification and wide safety margins. On the other hand, opacity, corrosion, and innovative design choices require demonstration of the technology in experimental campaigns before using it in the industrial field. In recent years, Westinghouse Electric Company has begun the conceptual study of an intermediate size LFR [~460 MW(electric)] which, by exploiting the opportunities of the technology, aims at marketability over the next decade. One of the features is a passive heat removal system that allows, through different heat exchange mechanisms including conduction, convection, and radiation, for the transfer of decay heat from the reactor block to a pool of water inside the containment. The system is designed for indefinite heat removal thanks to channels that allow outside air to replace water following complete boiling. For the geometry of the system, the size, the materials, and the heat transfer mechanisms, an experimental activity is required to validate the prediction of the calculation codes and potentially support design optimization. The UK Department for Business, Energy & Industrial Strategy has recently subsidized the design, procurement, installation, and operation of the Passive Heat Removal Facility, an experimental facility to study the innovative safety system. This paper presents the activities of scaling, design, pretesting, and installation of that facility
High filler content acrylonitrile-butadiene-styrene composites containing tungsten and bismuth oxides for effective lead-free x-ray radiation shielding
No full textAcrylonitrile-butadiene-styrene (ABS) based composites with a high content of tungsten and bismuth oxide were developed using an innovative process to obtain lead-free x-ray shielding materials. ABS was chosen for its good mechanical properties and its widespread availability as a recycled material. The composites underwent flexural tests, Shore D hardness tests, thermogravimetric and morphological analysis, and their x-ray attenuation properties were determined through numerical simulations and experimental measurements. Despite their high filler content (up to 75 wt%), the composites showed good filler dispersion within the polymeric matrix and maintained their mechanical properties. Across the investigated energy range (50–150 kV), the lead equivalence for x-ray shielding was achieved with composite plates containing 75 wt% of tungsten and bismuth oxide, at thickness values corresponding to a weight increase of only 29% and 36%, respectively, in comparison to lead. These findings pave the way for a new generation of lead-free x-ray shielding materials. Moreover, their mechanical properties, including flexibility for potential application in wearable personal protective equipment, can be tailored by adjusting the filler content. Highlights: High filler content lead-free ABS composites with WO3 and Bi2O3 were developed. They show good polymer/filler interfacial adhesion and flexural properties. Numerical simulations of their x-ray shielding properties were performed. Experimental tests with polychromatic sources confirmed good x-ray attenuation. Results pave the way for the development of new lead-free x-ray shielding systems
Recommendations for the future regulation of fusion power plants
Get PDFThe discussion in the international community on how fusion power plants (FPPs) will be licenced and regulated is ongoing. As such, there is a concerted drive from the European stakeholders to understand the requirements from such a framework and how to best establish it with the aim of easing the licensing process of FPPs. Initiated by the EUROfusion consortium, a group of European experts were convened to produce a set of recommendations on the regulatory framework for the safety and licensing of FPPs. To do so effectively, the group assessed lessons learned from existing fusion facilities, reports by International Atomic Energy Agency and European Commission on FPP safety and the on-going work by the UK government, US Nuclear Regulatory Commission and Canadian Nuclear Safety Commission, as well as the licensing process of ITER. As a result, commonalities between fusion and fission were identified in terms of fundamental safety objectives which could facilitate parity in certain framework aspects. However, significant differences to any such implementation were also identified, particularly with respect to the lower hazard potential inherent to FPPs and how to remain proportionate to the associated safety challenges and the physical principles behind these two types of reactors together with their associated technologies. The recognition of the differences in the safety challenges in FPPs and fission-based nuclear power plants (NPPs) is paramount to future regulatory framework development. Ultimately, regulatory frameworks depend upon a country’s legal framework, therefore it is apparent that a common global regulatory framework for FPPs is not possible. However, as with present-day NPP regulation, efforts could be made to develop harmonised approaches to FPP regulation to provide common levels of protection. In view of this objective, 12 recommendations are presented across 4 topics: regulations, international databases, codes and standards, safety demonstration rules and regulatory approaches. These recommendations are provided to inform and advise potential future actions on FPP regulatory framework and licencing process principles
An Innovative Methodology for Evaluating Power System Adequacy, Integrating Analyses of Both the Reliability and Anomalous Behaviour of Components
No full textPower systems adequacy assessment represents a complex task and many methodologies have been proposed to address its complexity. Different approaches have been investigated in literature: deterministic, probabilistic, analytical, analytical adaptive sampling approach, etc. The aim of this paper is proposing a probabilistic method combining both state sampling method and composite system analysis considering power system components reliability, reliability of power supply to electricity consumers, anomalous behaviour of the grid components, the presence of the non-programmable generation in the power system. Two case studies are analysed to show the proposed methodology effectiveness
Implementation of an On-Line Reactive Source Apportionment (ORSA) Algorithm in the FARM Chemical-Transport Model and Application over Multiple Domains in Italy
No full textA source apportionment scheme based on gas and aerosol phase reactive tracers has been implemented in the chemical-transport model FARM, to efficiently estimate contributions of different sources to ambient concentrations. The on-line scheme deals with all the main processes that the chemical species undergo in the model, to enhance consistency with the calculation of bulk concentrations. The fate of precursors through gas-phase chemical reactions is followed by an efficient solver that determines their incremental reactivity, while the contributions to the secondary particulate species from their gaseous precursors is determined by assuming the thermodynamic equilibrium between the two phases. The paper details the new employed methodologies and illustrates the application of the apportionment scheme (based on 6 source sectors) to PM10 and O3, simulated on three domains of different dimensions in Italy, all sharing the same horizontal resolution and a common region (Lombardy). Spatial patterns of results show, on average, a relevant contribution of heating on PM10 concentration in January, with local hotspots dominated by road traffic. Contributions appear consistent in the three simulated domains, apart from the boundary conditions, influenced by the dimension of the domain. Hourly series of contributions to O3 concentrations in July at three selected sites show the dominance of boundary conditions, underlining the large scale of O3 formation. Finally, for PM10 components, the resulting sectorial contributions are compared with the impacts computed via the brute force method, showing that results are similar for elemental carbon and sulfate, while they are different for nitrate and ammonium, due to a different allocation of contributions and impacts between the methods. Each approach responds in principle to a different purpose, and their combined use provides possibly a wide set of information useful for addressing the different air quality management needs
Electric Transmission and Distribution Network Air Pollution
No full textThere is a consensus within the scientific community regarding the effects on the environment, health, and climate of the use of renewable energy sources, which is characterized by a rate of harmful polluting emissions that is significantly lower than that typical of fossil fuels. On the other hand, this transition towards the use of more sustainable energy sources will also be characterized by an increasingly widespread electrification rate. In this work, we want to discuss whether electricity distribution and transmission networks and their main components are characterized by emissions that are potentially harmful to the environment and human health during their operational life. We will see that the scientific literature on this issue is rather limited, at least until now. However, conditions are reported in which the network directly causes or at least promotes the emissions of polluting substances into the environment. For the most part, the emissions recorded, rather than their environmental or human health impacts, are studied as part of the implementation of techniques for the early determination of faults in the network. It is probable that with the increasing electrification of energy consumption, the problem reported here will become increasingly relevant
Application of Italian Guidelines for structural-foundational and seismic risk classification of bridges: The Fabre experience on a large bridge inventory
No full textThe recent issuance of Guidelines for the classification and management of risk, safety assessment, and monitoring of existing bridges has standardized the methodology for analyzing the safety and managing bridges at a national level. The Guidelines propose a multi-level analysis approach, where the assessment of structures is conducted with increasing levels of detail and complexity. This paper describes the work carried out by the Fabre Consortium, the Italian scientific alliance on risk assessment and monitoring of civil infrastructural systems, together with ANAS s.p.a.; one of the major Italian road authorities, for the implementation of the Italian Guidelines to a large bridge inventory distributed over the Italian territory. This paper is specifically devoted to structural-foundational and seismic risk classification. The results of the application of the methodology to a large database is presented together with statistical analyses on parameters determining hazard, vulnerability and exposure and with the definition of the most recurrent typological bridge classes within the bridge inventory
Process Optimization in Laser Welding of IN792 DS Superalloy
No full textNi-base superalloys are employed to produce parts of aeronautic engines, space vehicles and power plants. During the production process or lifetime of components, cracks may occur which affect their performance. Reliable repairs can be carried out through high-energy density welding techniques. This work investigated laser welding of the directionally solidified IN792 DS superalloy. The characteristics of the original material and their evolution in the base metal, heat-affected zone and melt zone after laser welding in different conditions and post-welding heat treatment were investigated through micro-hardness tests, light and scanning electron microscopy observations. The study allowed to optimize the process parameters and post-welding heat treatment, obtaining joints without macro-defects, such as cracks and pores, and with properties and microstructures of the melt zone like those of base metal
Synergistic interplay of thermodiffusive instability and turbulence in premixed flames
No full textIn this work, we experimentally analyze the interplay of thermo-diffusive (TD) intrinsic flame instabilities and turbulence in premixed flame propagation. We utilize methane/hydrogen/air Bunsen flames at atmospheric pressure and variable hydrogen content, and variable turbulence intensity. Experiments are designed to maintain the laminar unstretched premixed flame speed constant by adjusting the equivalence ratio φ for each flame. As the hydrogen content is increased and φ is decreased, thermo-diffusive intrinsic flame instabilities are gradually promoted. We study the effect of thermo-diffusive instability on the global consumption speed by analyzing the contribution of flame surface area increase and flame mean reactivity measured via a stretch factor. We observe that the turbulence-instability interplay mainly occurs through an enhancement of flame reactivity and not flame area. In addition, a power spectral density (PSD) analysis of the flame curvature reveals that the spectra of unstable flames are consistently more energetic due to the wider range of linearly unstable scales interacting with the turbulent integral scale. A forced weakly nonlinear numerical model is also utilized to aid in the understanding of the experimental findings. The model exhibits a characteristic unforced PSD, representing the energy content of the typical spatiotemporal chaotic TD-unstable solution. When forced, the model exhibits PSD that emerge from the interplay of the turbulent spectrum and the characteristic TD-unstable spectrum, and, as a result are consistently more energetic than the TD-stable spectra