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Abstract: Soil structure is one of the most important environmental factors affecting root architectural development and consequently plant yield. Understanding how plant roots respond to soils with variable soil structure is important as it enables soil management practices that promote optimal root growth. Many contemporary, non-invasive experiments investigating how plant root architecture responds to soil structural variations have often focused on compaction, often neglecting the role of soil aggregate size in determining root configuration. To better understand this, in this study, we used non-invasive neutron and X-Ray imaging to investigate how variable aggregate size affects the early root architectural establishment in wheat plants. Sandy loam soil derived macro-aggregates of two distinct sizes (0.25−0.5 and 2−4 mm) were used to infer the suitability of each aggregate size for use in wheat seedbeds. We also grew wheat seedlings in partitioned containers with the two different aggregate size classes filled side by side to establish whether there would be preferential growth of roots in either aggregate size class. Our results showed significantly increased root growth in the smaller 0.25−0.5 mm aggregates as compared to the larger 2−4 mm aggregates. This was mainly as a result of enhanced lateral root growth when the wheat plants were grown in the finer aggregates. On the other hand, coarser aggregates induced significantly increased seminal root axes which partially offset the differences in total root length between the two aggregate sizes. Plants growing in partitioned containers similarly indicated preferential root growth in smaller aggregate with an even more pronounced difference in root growth in the smaller aggregates. As inferred from our results, seedbeds dominated by smaller macro-aggregates (finer soil tilth) may be optimal to enhance wheat seedling root growth in sandy loam soils.

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Abstract: Active Virosomes (AVs) are derivatives of viruses, broadly similar to ‘parent’ pathogens, with an outer envelope that contains a bespoke genome coding for 4–5 viral proteins capable of eliciting an antigenic response. AVs are essentially novel vaccine formulations that present on their surface selected viral proteins as antigens. Once administered, they elicit an initial “anti-viral” immune response. AVs are also internalised by host cells where their cargo viral genes are used to express viral antigen(s) intracellularly. These can then be transported to the host cell surface resulting in a second wave of antigen exposure and a more potent immuno-stimulation. A new 3D correlative microscopy approach is used here to provide a robust analytical method for characterisation of Zika and Chikungunya-derivatised AV populations including vesicle size distribution and variations in antigen loading. Manufactured batches were compared to assess the extent and nature of batch-to-batch variations. We also show preliminary results that verify antigen expression on the surface of host cells. We present here a reliable and efficient high-resolution 3D imaging regime that allows the evaluation of the microstructure and biochemistry of novel vaccine formulations such as AVs.

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Abstract: Climate change, and the need of recycling, are two interconnected topics that are gaining more and more relevance nowadays. In order to decrease the CO2 emissions and reduce, or contain, the pollution that is having devastating effects on our climate, recycling seems to be a necessity that can not be postpone or diminished anymore. In the effort of reducing pollution, the aluminium world (industry and Academia) is playing an important role. Recycling aluminium, in fact, require only 10% of the energy necessary to extract it form the bauxite ore, leading to a massive energy and cost saving, as well to a reduction on the CO2 emissions equivalent to take off the road 900000 cars for 12 months. Up to now, the only closed loop recycling process is the one for usage beverage cans (UBC): used cans are collected, molten together, and used again to create new cans without the addition of any other material. When it comes to the automotive industry things are a bit more complicated. There are two main ways, adopted by industries, to recycle Al alloys depending on their composition. Wrought alloys are recycled remelting the scrap with primary Al, and cast alloys are obtained remelting wrought alloys and adjusting their composition for the different purposes. Although these two methods meet the requirement so far, they will lead to a nonrecyclable scrap surplus in the near future, consequently, new possibilities are being explored. In this work, a method to recycle aluminium alloys based on fractional solidification is proposed. The technology developed is based on an idea proposed by A.L Lux and M.C Flemings in which a semisolid alloy is isothermally squeezed towards a filter. Lux and Flemings tested their method on Sn-Pb alloys and on a small scale (500 g). The technology developed in this thesis, has been tested first on model aluminium alloys, and once the optimised procedure was established, on real aluminium scrap alloys, and on a bigger scale (up to 3 kg). The effect of several parameters (temperature, squeezing procedure, ultrasound, and grain refinement) on the purification efficiency was investigated and a 60% purification efficiency was achieved. Along with the technology development, a more fundamental study was carried out focusing on the investigation of the semisolid deformation, the liquid migration through the mush and the role of morphology on the permeability of the semisolid alloy. Finally, through the use of a numerical model, the feasibility of the Scheil-Gulliver approach to our case study, was investigated.

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Abstract: Understanding how gas diffusion electrodes are working is crucial to improve their performance and cost efficiency. One key issue is the electrolyte distribution during operation. Here, operando synchrotron imaging of the electrolyte distribution in silver-based gas diffusion electrodes is presented. For this purpose, a half-cell compartment was designed for operando synchrotron imaging of chronoamperometric measurements. For the first time, the electrolyte distribution could be analyzed in real time (1 s time resolution) even in individual pores as small as a few micrometers. The detailed analyses of dynamic filling processes are an important step for understanding and improving electrodes.

Open Access

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Abstract: Since the outbreak of the SARS-CoV-2 pandemic, there have been intense structural studies on purified viral components and inactivated viruses. However, structural and ultrastructural evidence on how the SARS-CoV-2 infection progresses in the native cellular context is scarce, and there is a lack of comprehensive knowledge on the SARS-CoV-2 replicative cycle. To correlate cytopathic events induced by SARS-CoV-2 with virus replication processes in frozen-hydrated cells, we established a unique multi-modal, multi-scale cryo-correlative platform to image SARS-CoV-2 infection in Vero cells. This platform combines serial cryoFIB/SEM volume imaging and soft X-ray cryo-tomography with cell lamellae-based cryo-electron tomography (cryoET) and subtomogram averaging. Here we report critical SARS-CoV-2 structural events – e.g. viral RNA transport portals, virus assembly intermediates, virus egress pathway, and native virus spike structures, in the context of whole-cell volumes revealing drastic cytppathic changes. This integrated approach allows a holistic view of SARS-CoV-2 infection, from the whole cell to individual molecules.