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Dielectric characterisation of solar salt for volumetric heating applications in Power-to-Heat-to-Power systems
Get PDFCarnot batteries, or Power-to-Heat-to-Power systems, rely on solar salt as a thermal energy storage medium and require efficient and controllable heating technologies. However, conventional resistive heating is constrained by the low thermal conductivity of solar salt, leading to temperature gradients, local overheating, and material degradation, which motivates the exploration of alternative volumetric heating approaches. In this context, this study evaluates the feasibility of microwave-based volumetric heating of solar salt by analysing its dielectric behaviour across both solid and molten states. Dielectric properties were measured using the cavity perturbation method at 912 MHz and 2.45 GHz with different sample volumes and electromagnetic field configurations. Under these conditions, the sharp increase in electrical conductivity in the molten state results in high effective dielectric losses that violate the small-perturbation assumption underlying this technique. Consequently, the microwave measurements were complemented by four-electrode electrochemical impedance spectroscopy from 100 Hz to 1 MHz up to 550 • C to confirm the dominance of ionic transport mechanisms. The results show activation energies of 0.810 eV in the solid state and 0.148 eV in the liquid state, while extrapolated conductivities of approximately 160-170 S m −1 correspond to microwave penetration depths of about 1.3 mm at 912 MHz and 0.8 mm at 2.45 GHz, providing an application-relevant measure of the interaction between molten solar salt and electromagnetic fields. These findings indicate that accurate dielectric characterisation of molten solar salt at microwave frequencies requires measurement systems specifically adapted to highly conductive liquids and suggest that effective microwave heating strategies may rely on solar salt-compatible ceramic materials combined with appropriately tailored electromagnetic field distributions
Hugo Grotius and the law of friendship
Get PDFFriendship is a concept often evoked on the international stage and which has a long history in international thought. Despite falling to the sidelines for some time, it is experiencing a resurgence of interest. This paper sets out the position of friendship in the international thought of Hugo Grotius. I show that Grotius develops a law of friendship (amicitiae lex) which he incorporates into his just war theory. I argue that he makes a conceptual distinction between allies (socii) and friends (amici). The distinction concerns the underlying legal bases upon which they are founded. I therefore argue that we can map this distinction onto another of Grotius’s distinctions, that between perfect and imperfect rights. This is an important point because an infringement of a perfect right can result in war, but an infringement of an imperfect right cannot. Additionally, I highlight the supererogatory character to which Grotius accords friendship. I conclude by arguing that friendship is an important concept in Grotius’s international thought. I also suggest that Grotius is an instructive figure not only for those engaged in friendship’s revival but also for those concerned with the identity and relations of states
Unlearned responses of chicks, Gallus gallus domesticus, towards aposematic insect-like stimuli
Get PDFMany predators avoid aposematic prey that possess conspicuous warning displays. This aversion can include innate and learned components, either of which could be exploited by profitable Batesian mimics that resemble aposematic prey. The perceptual bias hypothesis proposes that predators’ unlearned aversions may not correspond exactly with the patterns of aposematic prey, and that inaccurate Batesian mimics gain a fitness advantage by maximizing the unlearned aversion of their predators rather than their similarity to the model. This would provide a particular advantage when faced with naïve predators that have not yet had the opportunity to learn an association between the warning patterns and defences of the prey they encounter. We tested this hypothesis in the context of hoverflies that mimic stinging Hymenoptera: do naïve predators avoid wasp-like stimuli, and, if so, is this bias stronger when encountering inaccurate mimics? We presented domestic chicks, Gallus gallus domesticus, with arrays of 3D-printed stimuli each of which concealed a mealworm, Tenebrio molitor. Each array included control nonmimetic flies and alternative warning-coloured stimuli drawn from a set of wasps and honey bees (models), hoverflies (mimics) and artificially generated intermediates. The chicks had never encountered insect-like prey or stimuli (other than mealworms) prior to these trials. We found no difference in the order in which the stimuli were attacked in different treatments, but did find that chicks were slightly slower to open dishes with aposematic as opposed to control stimuli. Our results do not provide strong support for the perceptual bias hypothesis in the case of hoverflies, but we do find evidence of variation in the unlearned response towards insect stimuli dependent on appearance. These differences illustrate the importance of defensive signals, both honest and deceptive, in influencing predator behaviour even from the first encounter
Observation of quantum strong Mpemba effect
Get PDFAn ancient and counterintuitive phenomenon known as the Mpemba effect (water can cool faster when initially heated up) showcases the critical role of initial conditions in relaxation processes. How to realize and utilize this effect for speeding up relaxation is an important but challenging task in purely quantum system till now. Here, we experimentally study the strong Mpemba effect in a single trapped ion system in which an exponentially accelerated relaxation in time is observed by preparing an optimal quantum initial state with no excitation of the slowest decaying mode. Also, we demonstrate that the condition of realizing such effect coincides with the Liouvillian exceptional point, featuring the coalescence of both the eigenvalues and the eigenmodes of the systems. Our work provides an efficient strategy to engineer the dynamics of open quantum system, and suggests a link unexplored yet between the Mpemba effect and the non-Hermitian physics
Interfacing with history: curating with audio augmented objects
Get PDFThis article presents and discusses the results from visitors’ interactions with two audio augmented reality experiences containing audio augmented objects; physical, real-world objects to which virtual audio sources have been attached. It then proceeds to discusses the commonly identified themes arising from the observation of visitors’ behaviour within these experiences and the analysis of their verbal and written feedback. The curatorial potential of audio augmented objects is discussed and, by way of conclusion, their functionality as interfaces to digital audio archival content is proposed, along with their ability to reframe, re-contextualise and create renewed experiences with existing collections of silenced museum exhibits
Modulating G6PD/PGD to overcome FSP1/DHODH-mediated ferroptosis defense: A novel oridonin derivative suppresses liver cancer
No full textBackground: Hepatocellular carcinoma (HCC), a globally prevalent malignancy with high mortality rates, presents an unmet need for innovative effective therapies. Purpose: This study aimed to explore the anti-tumor potential of compound XD, a novel oridonin derivative, on HCC and its underlying mechanism. Experimental Approach: The anti-tumor effects of compound XD were investigated in several HCC cells lines and mice models. The mechanism of XD was investigated using FACS, qPCR, WB, ELISA, IHC, siRNA and plasmid transfection. Key Results: Compound XD demonstrated potent inhibitory effects, surpassing sorafenib with a maximum of 10-fold lower IC50 values against HCC cell lines. Its anti-cancer activities were ferroptosis dependent, which could be attenuated by ferroptosis inhibitors including deferoxamine, ferrostatin-1 and N-Acetyl-Cysteine. Unlike sorafenib, XD decreased two pivotal regulators FSP1 and DHODH to induce ferroptosis, while their overexpression partially mitigated XD-induced cytotoxicity and lipid peroxidation. In addition, XD treatment decreased cellular NADPH levels and inhibited the expression of G6PD and PGD in NADPH generation. Overexpression of G6PD or PGD reversed FSP1 and DHODH downregulation, rescuing the ferroptosis induced by XD. Bioinformation analysis indicated the significant upregulation of G6PD and PGD in clinical HCC patients and was positively correlated with cancer stages. Molecular docking and CETSA assay confirmed the binding capacity of XD with G6PD and PGD protein. Finally, XD dose-dependently inhibited liver tumor growth and induced ferroptosis- related markers in mice. Conclusion and implications: This study suggests XD as a potential ferroptosis inducer and the potential role of G6PD/PGD/FSP1/DHODH axis in governing ferroptosis sensitivity in HCC
Phylogenetic analysis of paired breast carcinomas identifies genetic events associated with clonal recurrence and invasive progression
Get PDFDevelopment of ipsilateral breast carcinoma following a diagnosis of breast ductal carcinoma in situ (DCIS) has been assumed to represent recurrence of the primary tumour. However, this may not always be the case, and it is important to determine how often such recurrences represent new tumours. Ipsilateral primary–recurrence pairs (n = 78) were sequenced to test their clonal relatedness. Shared genetic events were identified from whole exome sequencing (n = 54 pairs) using haplotype-specific copy number and phylogenetic analysis. The remaining pairs were sequenced using a targeted panel or low-coverage whole genome sequencing. We included 32 non-recurrent DCIS to compare recurrent and non-recurrent disease. We found that 7% of DCIS recurrences were non-clonal by whole exome sequencing, indicative of a new breast carcinoma. Lower resolution methods detected a higher non-clonality rate (29%). By comparing primary DCIS with their recurrence, we found that the evolution of DCIS to invasive disease was associated with increased ploidy and copy number events. TP53 mutations were enriched in DCIS with clonal recurrence compared with non-recurrent DCIS. Our results verify that de novo ‘recurrent tumours’ of independent origin occur in patients who may be at high risk. © 2025 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland
Situational judgement testing at different stages of undergraduate medical training and the risk of professionalism lapses: A cohort study
Get PDFIntroductionIdentifying medical students at risk of professionalism lapses is critical for future patient safety. Situational Judgement Tests (SJTs) are commonly used to assess procedural knowledge of professionalism. Evidence suggests SJT scores can predict professionalism lapses, though longitudinal data across different stages of medical training are lacking. This study investigates the relationship between SJT performance at three points in pre-qualification medical education and professionalism lapses.MethodsA longitudinal study was conducted using linked data from the UK Medical Education Database (UKMED) and the University of Nottingham. Data were available for 705 students who sat a professionalism-focused SJT in their second year (2016 to 2018). Professionalism lapses were identified using concern forms. The study used scores from three SJTs administered at different stages: the University Clinical Aptitude Test (UCAT) at application; a Nottingham Medical School (NMS) test mid-training, and the UK Foundation Programme (UKFP) SJT, at the end of medical school. The relationship between SJT scores and the odds of a professionalism lapse was modelled using logistic regression.ResultsPerformance on the NMS SJT was statistically significantly associated with the odds of professionalism lapses (Odds Ratio [OR] 0.64, p = 0.001) even after adjusting for educational and cognitive performance (OR 0.68, p = 0.005). The UKFP SJT scores showed a univariable (0.66, p = 0.006) but not an independent relationship with the outcome (OR 0.77, p = 0.14). The UCAT SJT scores were not statistically significantly predictive of professional lapses, on univariable (OR 0.85, p = 0.34) or multivariable analysis (OR 0.92, p = 0.66).ConclusionsSJTs can support medical professionalism in students. They are likely to be most effective in this context when they are administered during training, rather than as a selection measure for entry to medical school. Moreover, SJTs designed to have specific, professionalism-focused content and a limited cognitive load are most likely to add unique value in this respect
Nicotiana benthamiana as a Source of Cowpea Mosaic Virus‐Derived Particles That Specifically Package Designer RNAs
Get PDFThe coupling of replication and encapsidation in the bipartite plant virus, cowpea mosaic virus (CPMV), has been used to specifically incorporate designer RNA molecules into viral particles via transient expression in Nicotiana benthamiana. This is achieved by placing the desired RNA sequence between the 5′ and 3′ UTRs of CPMV RNA-2 so that the cargo RNA can be recognised by the RNA-1-encoded replicase. Replication and encapsidation of cargo RNA are achieved by co-infiltrating with CPMV RNA-1 to provide replication functions and a non-replicating construct that encodes the precursor of the viral coat proteins, VP60. Encapsidation within CPMV particles stabilises the RNA such that it can be stored for prolonged periods at +4°C. Investigation of the length and sequence of the RNA that can be efficiently incorporated showed that a wide range of different RNA molecules are tolerated, provided that the length does not significantly exceed that of RNA-1 (6.0 kb). In contrast to previously published conclusions, we show here that a self-replicating version of RNA-1 is not required for the replication and packaging of cargo RNA constructs. Use of a non-replicating version of RNA-1 not only eliminates the packaging of RNA-1 but also increases the yield of particles containing the desired cargo RNA. Such particles have the potential to be used as delivery systems for bespoke RNAs to target cells
Resisting and enabling domination: voluntary organisations' efforts to regulate prison and police detention
No full textMobilizing a neo-republican account of domination, we explore voluntary organizations’ efforts to regulate prison and police detention. We find that regulatory functions ‘on the books’ are insufficient to counteract detainee domination ‘in action’, as power is neither reliably controlled by common knowledge and effective rules, nor under sufficient control by persons and groups subject to those rules. Using a large, original qualitative dataset, we present four antipowers through which voluntary organizations seek to regulate domination in detention: (1) providing information and advice to detainees; (2) holding rule makers to account on behalf of detainees; (3) campaigning for different rules; (4) establishing democratic participation by prisoners. Simultaneously, we illustrate how voluntary organizations may contribute to domination and be subject to dominating practices from authorities
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