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Characterization and testing of a multiphase superconducting axial machine for electric aircraft
No full textGrowing environmental concerns and increasingly stringent emission regulations are driving the energy transition toward electrification. The aviation sector, facing rising air traffic and the urgent need for decarbonization, is a strong candidate for this transition. Significant efforts are being made to develop propulsion technologies that minimize emissions while maintaining high performance. Cryo-electrification, which integrates high temperature superconducting (HTS) machines with cryogenic cooling, is a promising solution for this transition. The exceptional current density of HTS materials enables electric machines with high specific power density (SPD), a key requirement for aircraft applications. This work focuses on the development of a variable pole multiphase axial flux machine designed for integration into a highly flexible, fault-tolerant electromechanical drive. The machine consists of two semi-stators and a rotor constructed from slices of HTS REBCO (rare-earth bismuth copper oxide) tapes. The variable-pole configuration allows the machine to function as an electronic gearbox, providing operational flexibility. The magnetic flux generated by the stator is trapped in the HTS rotor, forming the basis of its superconducting operation. To validate the concept, flux measurements will be performed using pick-up coils. Additionally, preliminary finite element method (FEM) simulations were performed. Experimental results will be presented to demonstrate the feasibility of this design. This study serves as a proof of concept, but further optimization is required to achieve the high SPD necessary for aviation applications
Neural networks for faster laser ultrasound tomography in tissue phantoms
Get PDFSpeed of sound (SoS) mapping provides quantitative and localised information about a material’s acoustic properties, allowing identification of spatial compositional changes. In biomedical applications, SoS variations can inform tissue characterisation or improve image reconstruction algorithms that typically assume a constant SoS. However, conventional time-of-flight (ToF) tomography methods remain computationally intensive. This study presents experimentally derived tomographic reconstructions of SoS maps of heterogeneous structures from all-optically acquired data using a convolutional neural network (CNN). The CNN, trained on simulated data, enables near real-time, high-quality tomographic reconstructions. The novelty of this work lies in the integration of a laser ultrasound (LU) data acquisition setup with a CNN-based reconstruction approach, demonstrating its potential for remote and flexible inspection of biomedically relevant samples. The CNN was trained using simulated data based on ultrasonic wave propagation models and achieved tomographic reconstructions of a 77 mm × 77 mm area in less than 6 ms. Data were acquired from four tissue-mimicking phantoms (30 mmdiameter) with inclusions of varying size (minimum 6 mm diameter) and SoS (minimum variation 25 m/s). When compared with published, in vivo studies using mammography (MM), conventional ultrasound, and magnetic resonance imaging (MRI), the proposed method yielded 5.73% mean sizing error for phantoms and inclusions relative to the ground truth, highlighting the clinical potential of the LU-CNN framework and the need for further in vivo testing. These findings underscore the method’s potential as a precise, faster alternative to conventional imaging and reconstruction methods used in clinical practice
Impact of missing data on the construction of LISA time-delay-interferometry Michelson variables
No full textWe investigate the impact of missing input data on the construction of second-generation time-delay-interferometry (TDI) variables, which enable data analysis for the Laser Interferometer Space Antenna (LISA). TDI relies on the introduction of precise time delays into the raw interferometric data streams before they are combined to suppress otherwise dominant laser phase noise. We show that a single missing sample, corresponding to 0.25 s of data, will result in an effective data gap of approximately 90 s in the second-generation TDI output if further measures are not taken. This additional gap is largely independent of the initial gap duration, but it increases linearly with the order of the fractional-delay filter used for the computations. For a realistic gap scenario, incorporating both planned and unplanned data interruptions consistent with a target duty cycle of approximately 84%, we find that frequent, short-duration gaps (e.g., a total of 1000 per year, each of which has a duration of approximately 100 s) could result in an additional loss in the TDI variables of about one day per year, corresponding to a reduction of approximately 0.3% in duty cycle. This amounts to a loss of approximately one day of LISA data suitable for the global fit per year
Understanding the Premier League social strategy
No full textIn this chapter we will analyse the ecology and growth of social media in this league. We will place it within the wider context of digital media developments in the UK media sector and beyond. We will examine the strategic thinking behind the usage of social media by the league and also at a number of EPL clubs. At the same time, the published content and the engagement produced in the public will be analysed and the formulas for evaluating their strategies on social networks will be shown. What emerges is a complex area in which there is not any one organisational structure adopted to fit all the clubs or the league. Rather we see a fast moving sector where the balance between securing high social media metrics and actual fan engagement is both complex and requiring of sustained investment by the league and the clubs
First human whole-body biodistribution and dosimetry analysis of [18F]LW223, a novel TSPO PET radiotracer
Get PDFPurpose:
The 18 kDa translocator protein (TSPO) has been a central molecular target for imaging inflammation in the preclinical and clinical research settings across a plethora of applications, including neuroinflammation, cardiovascular inflammation and cancer. Recently, we reported the development of [18F]LW223 as a third-generation TSPO positron emission tomography (PET) radiotracer with binding to human TSPO independent of the rs6971 genetic polymorphism. This study reports the first whole-body human analysis, including biodistribution and dosimetry calculations, following intravenous administration of [18F]LW223.
Methods:
Whole-body PET images were acquired over 250 min after intravenous bolus injection of 184.3 ± 20.2 MBq of [18F]LW223 in healthy adult human volunteers. Volumes of interest (VOIs) in different source organs were manually delineated by three independent observers, then time-activity curves were generated for residency times calculations for subsequent quantification of radiation equivalent and effective doses using OLINDA/EXM 2.2 software.
Results:
The radiotracer biodistribution in humans recapitulated known TSPO expression in various tissues. The main elimination route was found to be hepatobiliary, and the critical organ was the intestine. The cumulated radioactivity excreted by the kidneys was < 10% over the measurement period and no bone uptake suggestive of in vivo defluorination was observed in any of the study subjects. The effective dose ranged between 11.8 ± 0.9 and 12.5 ± 0.9 µSv/MBq. Inter-observer VOI variability had no impact on estimated organ and whole-body effective doses.
Conclusion:
[18F]LW223 is predominantly excreted by the hepatobiliary route with no evidence of in vivo defluorination but demonstrates marked uptake into tissues with known TSPO expression. It complies with radiation limits and guidelines recommended by regulatory authorities and is in line with previously reported [18F]-labelled radiotracers, such as [18F]fluorodeoxyglucose. [18F]LW223 is suitable for translation into human clinical studies
Physics-informed emulation of systemic circulation for fast parameter estimation and uncertainty quantification
No full textThere are many computational models set up to predict blood flow and pressure in vascular networks. Methods for a single forward solution of such models are well established but become problematic in clinical applications, where model calibration and patient-specific parameter estimation call for repeated forward simulations of the model requiring substantial computational costs. A potential workaround is emulation, which approximates the original mathematical model by a statistical or machine learning surrogate model. Our methodological framework is based on physics-informed neural networks, with a particular focus on patient-specific model calibration. Once fully trained, our machine learning model predicts flow and pressure waveforms in a fraction of the time required by the numerical solver, enabling fast parameter inference and inverse uncertainty quantification. The proposed framework is applied to clinical data from four patients diagnosed with a Double Outlet Right Ventricle (DORV), a congenital heart defect where both the aorta and main pulmonary artery connect to the right ventricle, potentially leading to insufficient oxygen delivery to the body and hence requiring careful blood flow monitoring. We assess the performance of our method in a comparative evaluation study that includes several alternative state-of-the-art machine learning methods, and we quantify the improvement achieved in terms of accuracy and efficiency gains
Effects of various concentrations and volumes of potassium sorbate on colostrum bacterial contamination over time at ambient and refrigeration temperatures
Get PDFPreservation and storage of colostrum on farm is challenging, since cold temperature storage facilities (refrigerators and freezers) often cannot accommodate the volume of colostrum required to feed calves. Potassium sorbate preservative (PSP) is a readily available food grade preservative used in wine and cheese production; shown to be very effective at preserving colostrum at both refrigeration and ambient temperatures. Aims of the current work were to determine the optimal concentration and inclusion volume rate (IVR) of PSP to preserve bovine colostrum for feeding to neonatal calves. Twenty individual cow ‘point of feeding’ colostrum samples were collected and frozen at −20°C for 4–6 weeks before testing (purposively selected). Three PSP concentrations were created (25.4%, 32.2%, and 39.1%) by mixing potassium sorbate crystals with 100 mL of distilled water. For each of these concentrations 50 µL (1% by volume) and 25 µL (0.5% by volume) were added to each 5 mL aliquot of colostrum to create 2 different IVR. For each concentration and IVR, one aliquot was stored at ambient temperature (AT = temperature monitored in the laboratory between 23.1°C and 24.6°C) and one aliquot was refrigerated (RF = temperature monitored in refrigerators between 3.1°C and 4.2°C). Baseline bacteria counts were also measured for each colostrum sample. Aliquots were tested for degree of bacterial contamination at 24 h, 72 h and 168 h. Mixed linear regression models were constructed using total coliform counts (TCC) and total bacteria counts (TBC) as outcomes of interest, with concentration (30 g/100 mL; 40 g/100 mL or 50 g/100 mL), IVR (1% inclusion volume and 0.5% inclusion volume) and temperature (RF = 3.1–4.2°C or AT = 23.1–24.6°C) as predictors of interest. Survival analysis (with sample as a random effect term) was also used to account for bacteria counts too numerous to count (TNTC, assigned as 10,000,000 cfu/mL for TBC and 11,000 cfu/mL for TCC as these exceeded the highest measures). Bacteria TNTC was analyzed as a ‘failure event’ and the time frame at which these ‘failures’ occurred was analyzed. There was a statistically significant temperature by IVR interaction for the TCC outcome. RF was more effective than AT at preventing bacterial proliferation at 24 h and 72 h. Survival models showed a lower hazard of high contamination at IVR of 1% and concentration of 50 g/100 mL. In all cases, 50 g/100 mL concentration was more effective than concentrations of 30 g/100 mL and 40 g/100 mL or no preservative and 1% IVR was more effective than 0.5% IVR or no preservative at preventing bacterial proliferation at 24 and 72 h. A large number of samples in this work were initially contaminated with total bacterial species and this may have biased results, however this is representative of the current situation on most dairy farms
Robust adaptive immunity to MPXV in older people who received childhood vaccinia vaccination
No full textMonkeypox virus (MPXV) is a zoonotic Orthopoxvirus responsible for Monkeypox (Mpox),
historically associated with sporadic zoonotic transmission but increasingly characterised
by sustained human-to-human spread. While vaccinia-based vaccination is known to confer cross-protection against MPXV, the durability of such immunity over a human lifetime
remains incompletely characterised. Here, we assessed humoral and cellular immune responses to MPXV in octogenarians and nonagenarians vaccinated against smallpox during
childhood. Twenty-three adults aged 79–94 years (median 83), who self-reported childhood
vaccinia vaccination between 1925 and 1940, were recruited. MPXV-specific antibody responses were evaluated using ELISA, targeting homologous vaccinia and MPXV proteins,
and live-virus neutralisation assays. Cellular immunity was assessed by IFN-γ ELISpot
following stimulation with peptide pools derived from highly conserved vaccinia antigens.
Responses were also obtained from younger, recently MVA–BN-vaccinated and unvaccinated control donors. All historically vaccinated participants exhibited MPXV-reactive
IgG responses, with antibody binding and neutralisation levels comparable to recently
vaccinated individuals. Functional neutralising activity against MPXV was detected in
all donors, with ≥50% neutralisation observed in 78% of participants. Antibody concentrations correlated strongly with neutralisation capacity. T-cell responses were detectable
in all historically vaccinated donors, most prominently against the major core protein
A10L, although reduced magnitudes were observed in participants over 90 years of age.
No MPXV-specific humoral or cellular responses were detected in unvaccinated controls.
These findings demonstrate that childhood vaccinia vaccination induces durable humoral
and cellular immunity against MPXV persisting for over seven decades. Historical smallpox
vaccination status may therefore remain a relevant determinant of protection against Mpox
Flavor hierarchies with nonminimal irreducible representations
Get PDFWe propose a new class of flavor models in which the spurion that breaks Standard Model flavor
symmetries transforms in a nonminimal representation. Hierarchies in fermion masses, which arise from
multiple insertions of this spurion, may be generated in a technically natural, accidental manner, from a
handful of untuned O(1) elements in the UV. This relies explicitly on the non-Abelian nature of the
symmetry, distinguishing it from standard Froggatt-Nielsen-like scenarios. The pattern of flavor violating
operators at dimension-6 can radically differ from previously considered scenarios, and emphasises the
need for a broad flavor program across all generations
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