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Crash-stop failures in asynchronous multiparty session types
Get PDFFunding: The work is supported by EPSRC grants EP/T006544/2, EP/K011715/1, EP/K034413/1, EP/L00058X/1, EP/N027833/2, EP/N028201/1, EP/T014709/2, EP/V000462/1, EP/X015955/1, EP/Y005244/1, NCSS/EPSRC VeTSS, Horizon EU TaRDIS 101093006, and ARIA Safeguarded AI.Session types provide a typing discipline for message-passing systems. However, their theory often assumes an ideal world: one in which everything is reliable and without failures. Yet this is in stark contrast with distributed systems in the real world. To address this limitation, we introduce a new asynchronous multiparty session types (MPST) theory with crash-stop failures, where processes may crash arbitrarily and cease to interact after crashing. We augment asynchronous MPST and processes with crash handling branches, and integrate crash-stop failure semantics into types and processes. Our approach requires no user-level syntax extensions for global types, and features a formalisation of global semantics, which captures complex behaviours induced by crashed/crash handling processes. Our new theory covers the entire spectrum, ranging from the ideal world of total reliability to entirely unreliable scenarios where any process may crash, using optional reliability assumptions. Under these assumptions, we demonstrate the sound and complete correspondence between global and local type semantics, which guarantee deadlock-freedom, protocol conformance, and liveness of well-typed processes by construction, even in the presence of crashes.Peer reviewe
Mechanometallaphotoredox catalysis : utilizing increased throughput mechanochemistry to develop solvent-minimized aryl amination and C(sp2)-C(sp3) cross-coupling reactions with increased tolerance to aerobic conditions
Get PDFFunding: The authors thank the Leverhulme Trust for support (RPG-2023-110), the Engineering and Physical Sciences Research Council for funding (EP/W007517, EP/W015137/1, and EP/Z535291/1), and the European Commission (PhotoReAct ITN: 956324). F.M. thanks the EaSI-CAT CDT at the University of St Andrews for support in the form of a studentship.Photocatalysis as a tool used in organic synthesis has predominantly relied on the use of solvents, be it under homogeneous or heterogeneous conditions. In particular, metallaphotoredox catalysis reactions commonly use toxic organic solvents such as DMA and DMF. Herein, we demonstrate how mechanophotocatalysis, the synergistic union of mechanochemistry and photocatalysis, is compatible with this class of dual catalysis reactions involving both photocatalyst and nickel(II) cocatalysts. Using ball milling, these mechanistically complex reactions can be conducted in the absence of a bulk solvent and under air, affording high-yielding aryl aminations and C(sp2)-C(sp3) cross-couplings with alkyl carboxylic acids, alkyl trifluoroborate salts, and alkyl bromides. These advances are facilitated by the introduction of a novel reaction vessel design for conducting four mechanophotocatalysis reactions simultaneously. This work highlights the promise of solvent-minimized photocatalysis reactions, demonstrating that in these examples bulk solvent is redundant, thus significantly reducing this waste stream. Through time-resolved photoluminescence studies, we observed that the excited states of five different photocatalysts were quenched by oxygen more significantly in solution than in the solid state, providing evidence for the origin of the increased tolerance to aerobic conditions that these mechanophotocatalysis reactions experience.Peer reviewe
The challenge of polyanion redox in oxalates
No full textThe pursuit of high-energy-density lithium-ion and sodium-ion batteries has intensified the search for advanced cathode materials capable of multielectron redox processes. Polyanionic compounds, particularly those containing oxalate groups, have garnered significant interest due to their potential to exhibit both cationic and anionic redox activity. This study focuses on elucidating the conditions that trigger or suppress the redox behaviour of oxalate within these materials.
We have systematically investigated a series of transition metal oxalates, including those with sodium or potassium, and also mixed with other polyanionic groups. Electrochemical analyses, notably differential capacity (dQ/dV) plots, reveal characteristic peaks indicative of dual redox activity involving both the transition metal (Fe) and the oxalate anion (C₂O₄²⁻). These observations are corroborated by ex-situ Raman spectroscopy, Mössbauer spectroscopy, HAXPES analysis, and density functional theory (DFT) calculations, confirming the reversible participation of oxalate groups in the redox processes.
However, our findings indicate that the anionic redox activity of oxalate is significantly suppressed in the presence of additional polyanionic groups such as phosphate, sulfate, or anions like fluoride. This suppression is attributed to several factors: strong inductive effects from these groups reducing the electron density available for oxalate oxidation, increased structural rigidity hindering necessary lattice adjustments for redox activity, and competition for electron delocalisation that favors more electronegative anions over oxalate.
Understanding these inhibitory effects is crucial for the strategic design of next-generation cathode materials. By balancing structural stability with redox flexibility, it is possible to maximise the dual redox contributions of both cationic and anionic species. Our research provides valuable insights into the structural and compositional prerequisites for enabling oxalate redox behaviour, guiding future development of high-capacity, energy-dense cathode materials for advanced battery applications
Validation of facial attributions in leadership : trustworthiness and age in Chinese mid-level management
Get PDFThe attributions made to faces are well described by two dimensions of apparent trustworthiness (valence or warmth) and apparent competence (dominance and power) (1). This model has been extended to include a third dimension of apparent age and attractiveness (2). Previous research has tested the association between appearance and leadership attainment for high-level leaders such as elite politicians and chief executive officers of top performing organisations in the US and Western Europe. Here we focus on a Chinese organisational context and explore how facial attributions are associated with appointment at mid-level managerial positions. Participants rated leadership, competence, trustworthiness, attractiveness and age of faces of male employees of a Chinese Real Estate company. Our findings reveal that apparent trustworthiness and age are more critical predictors of leadership attainment than competence or attractiveness in the context of mid-level management in China. The study supports the three-dimensional attribution framework and reaffirms the importance of facial cues in leadership selection across diverse cultural settings.Peer reviewe
Biochemical characterisation and essentiality of proteins involved in myo-inositol metabolism from Trypanosoma cruzi
No full textmyo-Inositol is a precursor to the essential membrane lipid, phosphatidylinositol (PI). In Trypanosoma cruzi, PI may form inositol phosphorylceramide (IPC) and glycosylphosphatidylinositol (GPI)-anchored molecules/glycoproteins, which coat the parasite’s cell-surface for essential parasite-host interactions.
In T. cruzi, myo-inositol is putatively de novo synthesised and extracellularly scavenged. The project’s aim was characterising the putative inositol-3-phosphate synthase (TcINO1) from the de novo synthesis pathway and the myo-inositol transporter (TcMIT) from the extracellular uptake pathway.
Each protein was recombinantly expressed in E. coli. This demonstrated TcMIT is a multi-transmembrane (TM) domain protein with 12 likely TM domains, suggesting TcMIT might be an H⁺ symporter. Recombinant TcINO1 expression and purification allowed TcINO1 confirmation as a bona fide INO1 with Michaelis-Menten kinetics.
Heterocyclic fragment libraries were screened for compounds interacting with recombinantly purified TcINO1. Several Otava library compounds stabilised TcINO1, which demonstrated initial positive homotropic cooperativity.
TcINO1 and TcMIT were genetically manipulated in T. cruzi. This revealed de novo synthesised myo-inositol may be primarily utilised for alkyl acyl PI and incorporated into GPI-anchors, whilst extracellular myo-inositol might be mainly used for bulk diacyl PI for membranes or incorporated into IPC. Decreased exogenous myo-inositol may be compensated by de novo synthesis; however, the converse was not observed.
T. cruzi TcINO1 and TcMIT genetic manipulations demonstrated TcINO1 is cytosolic whilst TcMIT is plasma membrane bound. It also genetically validated both genes as essential T. cruzi genes.
Otava library compounds stabilising recombinantly purified TcINO1 were tested in parental strain T. cruzi. The three most potent compounds altered EC₅₀s in genetically altered TcINO1 T. cruzi cell lines. This strongly suggests TcINO1 is a chemically validated Chagas’ disease therapeutic target. The best compound had an EC₅₀ (EC₅₀ = 6.11 ± 0.31 μM) on par with Nifurtimox, the current Chagas’ disease therapy, and a high selectivity index, making it preferable over Nifurtimox
The logic of dynamical systems is relevant
Get PDFLots of things are usefully modelled in science as dynamical systems: growing populations, flocking birds, engineering apparatus, cognitive agents, distant galaxies, Turing machines, neural networks. We argue that relevant logic is ideal for reasoning about dynamical systems, including interactions with the system through perturbations. Thus dynamical systems provide a new applied interpretation of the abstract Routley-Meyer semantics for relevant logic: the worlds in the model are the states of the system, while the (in)famous ternary relation is a combination of perturbation and evolution in the system. Conversely, the logic of the relevant conditional provides sound and complete laws of dynamical systems.Peer reviewe
A review on electro catalysis of oxygen reduction reaction : enabling sustainable future energy
Get PDFThe field of electro catalysis, particularly the area of oxygen reduction reaction (ORR), has witnessed significant progress with far-reaching impacts in a variety of fields, as highlighted in recent research (Li et al.). Through the ORR mechanism, electro catalysis plays an important part in natural processes such as respiration, where it improves the conversion of oxygen to water in living organisms (Lane et al.). Theoretical importance does not restrict our comprehension of ORR processes in these biological systems. This has far-reaching implications for biomedical technology, such as implanted biosensors and biofuel cells (Li et al.). To optimize their performance, these technologies rely on efficient and selective ORR catalysts. Because of their high catalytic activity, noble metal catalysts such as platinum traditionally, platinum (Pt) and palladium (Pd) have been used as standards (Gasteiger et al.). Because of their scarcity and expensive cost, researchers have been pushed to investigate alternatives, resulting in substantial development in the design and synthesis of non-precious metal catalysts. As feasible alternatives, transition metal compounds, metal-free carbon materials, and hybrid Nano materials with high ORR activity, selectivity, and stability have developed (Zhu et al. the). These alternatives offer long-term and cost- effective energy transition solutions, indicating a significant shift in the catalytic environment. ORR electro catalysts hold the key to designing a more sustainable future, alongside their relevance in life sciences, biomedical technology, and fuel cells. In the future, the development of these catalysts will be critical in addressing global concerns such as renewable energy generation and environmental sustainability. Non-precious metal catalyst advances, as well as continued research into ORR processes, are opening the path for more efficient and sustainable beneficial energy conversion technologies. The chapter investigates the critical function of ORR electro catalysis in fuel cells, which transform chemical energy into electrical energy successfully. The incorporation of non-precious metal catalysts into fuel cells not only improves their performance but also adds to the progress of clean energy solutions. This is of particular significance as the globe encourages sustainable energy generation and lower greenhouse gas emissions. This includes the opportunity for widespread implementation of fuel cells as a clean energy source, reducing our dependence on fossil fuels and reducing the harmful effects of climate change
A modified Delphi exercise in physician-perceived risk factors for drug-induced pneumotoxicity in patients with rheumatological disease
Get PDFBackground Drugs used to treat rheumatic disease are associated with pneumotoxicity (drug-induced lung disease), but little is known about associated risk factors. Aim To determine expert physician-perceived risk factors for developing pneumotoxicity in patients with rheumatologic conditions. Methods A modified international 3-tier Delphi exercise was performed. Tier 1 determined patient and drug variables that physicians perceive to be risk factors. Tier 2 determined degree of risk associated with the Tier-1 derived variables. Tier 3 aimed to internally validate and stratify exemplar cases into risk categories. Results 134 pulmonologists and 49 rheumatologists responded to Tier 1;157 physicians completed all tiers. Perceived risk factors included: drug type; history of previous pneumotoxicity; age; smoking; underlying rheumatic disease type and activity; renal function; pulmonary hypertension; left ventricular failure;presence, nature, severity and progression of pre-existing interstitial lung disease. Tier 2 data stratified these variables into risk profiles e.g. never versus current smoking was perceived as low and high risk respectively. An example of perceived high risk resulting from Tier 3 is a 75-year-old current smoker with high-activity rheumatoid arthritis (RA) with severe, progressive ILD being started on methotrexate. A perceived low risk is a 75-year-old currentsmoker with moderate-activity RA and emphysema with no cardiac or renal disease and no pre-existing ILD being started on rituximab. A risk prediction scoring tool is being developed to be used in validation studies. Conclusion This modified Delphi exercise defined and stratified the perceived risk factors for developing pneumotoxicity. Age, current smoking, high underlying rheumatological disease activity, HRCT definite UIP and honeycombing, severity and progression of pre-existing ILD were perceived to be the highest risk-factors.Peer reviewe
Light-deformable microrobots shape up for the biological obstacle course
Get PDFEuglena gracilis microalga has been transformed into a soft bio-microrobot with light-controlled motion and deformation that can address diverse bio-challenges, such as drug delivery, diseased cell removal, and photodynamic therapy.Non peer reviewe
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