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Beyond wingtips: backbone alkylation affects the orientation of N-heterocyclic carbenes on gold nanoparticles
Get PDFThe effect of wingtip groups on the orientation of N-heterocyclic carbene (NHC)-based self-assembled monolayers (SAMs) on a variety of metal surfaces has received considerable attention. However, the influence of backbone substituents on orientation has received virtually no attention, despite the fact that backbone interactions are critical for upright orientation of thiolate-based SAMs and that backbone functionalization is important for many applications. To address this question, a series of gold nanoparticles (NPs) supported by NHCs featuring symmetrical or asymmetrical long alkyl backbone substituents and ethyl and isopropyl wingtips were synthesized. The gold NPs were characterized using UV-vis spectroscopy, electron microscopy, mass spectrometry, and surface-enhanced Raman spectroscopy (SERS). Experimental SER spectra were compared to simulated spectra, illustrating that both ethyl and isopropyl NHCs with symmetrical dodecyl long chains in the backbone adopt a primarily vertical configuration on the gold surface. However, the ethyl NHC with a single hexyloxy backbone substituent adopts mainly a flat configuration on the gold NP surface based on combined SERS and scanning tunneling microscopy (STM) results. This is attributed to on-surface interactions between long alkyl chains, which provide an unanticipated source of stability favoring the flat-lying orientation. Lastly, the thermal stability of the NHC-functionalized gold NPs at elevated temperatures was investigated. The dodecyloxy-functionalized NHC AuNPs remain thermally stable for 72 hours at 100 °C, representing a significant improvement over state-of-the-art NHC-AuNPs. NHCs containing isopropyl wingtip groups provide NPs with higher levels of stability than diethyl-substituted NHCs, regardless of backbone substituents. Taken together, our results highlight critical synthetic considerations for NHC ligand design, enabling control of ligand orientation and nanomaterial stability by tuning NHC backbone substituents
Enlightenment for the common people? Frederick II and the philosophes on popular prejudice, deception and education
Get PDFThe role of genomics in delivering the United Kingdom’s national action plan for confronting antimicrobial resistance 2024 to 2029
Get PDFAntimicrobial resistance (AMR) is a major threat to human and animal health, in addition to environmental resilience. Countries set the agenda on their national action against AMR in the form of National Action Plans (NAPs), with the UK’s latest NAP released in May, 2024. Advances in genomics have strengthened our ability to work towards NAP priorities; however, to date, no mapping of the role genomics plays in contributing to specific goals within the NAP has been undertaken. The UK Research and Innovation-funded Transdisciplinary Antimicrobial Resistance Genomics Network brought together a range of stakeholders to discuss the role of genomics for action on AMR and to deliver policy priority-led research, as outlined in the UK NAP 2024–29. We report our discussions in this Personal View, with key roles for genomics, including informing targeted stewardship in health-care settings, supporting AMR literacy, and supporting effective antimicrobial innovation. However, changes in infrastructure, communication, and cross-sector coordination are needed to support implementation
The factor structure and measurement invariance of parent-report strengths and difficulties questionnaire (SDQ) during a public health crisis
Get PDFThe parent-report Strengths and Difficulties Questionnaire (SDQ) is a widely used child and adolescent mental health screening tool. However, challenging environments, such as public health crises, may influence the construct validity of measures. To assess this, we examine SDQ measurement invariance, internal consistency, convergent and discriminant validity, composite, testretest, and interrater reliability across parents from the UK (n=9001) and Japan (n=365). We replicate the five-factor structure, which held across children’s age, gender, and between parent- and adolescent-report. We provide new evidence of SDQ invariance for special educational needs (SEN), across 6- and 1- month reporting windows, over different periods of restrictions, and between English (UK) and Japanese versions. Taken together, our findings suggest that parents interpreted the SDQ items in similar ways to pre-pandemic norms. Yet relatively low reliability of the conduct and peer relationship subscales, in particular, indicates a need for caution and scale revisions, especially when used for screening and diagnosis
Beyond species means - the intraspecific contribution to global wood density variation
No full textWood density is central for estimating vegetation carbon storage and a plant functional trait of great ecological and evolutionary importance. However, the global extent of wood density variation is unclear, especially at the intraspecific level. We assembled the most comprehensive wood density collection to date, including 109 626 records from 16 829 plant species across woody life forms and biomes (GWDD v.2, available here: doi: 10.5281/zenodo.16919509). Using the GWDD v.2, we explored the sources of wood density variation within individuals, within species and across environmental gradients. Intraspecific variation accounted for c. 15% of overall wood density variation (SD = 0.068 g cm−3). Variance was 50% smaller in sapwood than heartwood, and 30% smaller in branchwood than trunkwood. Individuals in extreme environments (dry, hot and acidic soils) had higher wood density than conspecifics elsewhere (+0.02 g cm−3, c. 4% of the mean). Intraspecific environmental effects strongly tracked interspecific patterns (r = 0.83) but were 70–80% smaller and varied considerably among taxa. Individual plant wood density was difficult to predict (root mean square error > 0.08 g cm−3; single-measurement R2 = 0.59). We recommend (1) systematic sampling of multiple individuals and tissues for local applications, and (2) expanded taxonomic coverage combined with integrative models for robust estimates across ecological scales
A cautionary note regarding the consequences of balancing for fair comparisons in population ecology
No full textPopulation ecology has amassed a significant volume of demographic data across the Tree of Life. Together, these data enable comparative analyses at unprecedented taxonomic and biogeographic scales to examine patterns of demographic performance and their mechanisms. However, macroecological analysis of heterogeneous data and models from diverse study systems comes with risks, and care must be taken to ensure that the patterns from comparative approaches are biologically meaningful, rather than driven by model-specific artifacts. Recently, a balancing approach has been proposed as a solution to ‘distorted’ population structure, particularly for evaluating transient (short-term) population dynamics. We argue that some distortion is the result of true biological processes, and that balancing over-corrects for distortion due to census timing (pre- vs. post-breeding). We lay out the relationship between demographic census design and the issues purported to be solved by balancing. Using a large dataset of carefully-selected matrix population models from plants and animals, we demonstrate that balancing changes biological interpretation of the relationship between reproductive traits and demographic resilience. We also highlight how application of balancing outside of its narrow original application to transient metrics can be problematic. We argue that meaningful comparisons require tailored approaches that respect the structure and context of demographic data. A more nuanced strategy–based on the biological realities of life cycles, census design, and reproductive strategies–will improve the robustness and interpretation of comparative demographic analyses
PS Atiyah: an academic autobiography
No full textPS Atiyah (1931–2018) was one of the world’s great legal scholars of the twentieth century and formerly Professor of English Law at the University of Oxford. He made immense contributions to, in particular, the law of contract and the law of torts.
Atiyah’s principal works include The Rise and Fall of Freedom of Contract, The Sale of Goods, An Introduction to the Law of Contract, Pragmatism and Theory in English Law, The Damages Lottery, Form and Substance in Anglo-American Law and Accidents, Compensation and the Law.
His work is of enduring relevance. His autobiography sheds light on his research and on the state of the academy in the second half of the previous century
Online 3-taxi on general metrics
No full textThe online k-taxi problem, introduced in 1990 by Fiat, Rabani and Ravid, is a generalization of the k-server problem where k taxis must serve a sequence of requests in a metric space. Each request is a pair of two points, representing the pick-up and drop-off location of a passenger. In the interesting “hard” version of the problem, the cost is the total distance that the taxis travel without a passenger. The problem is known to be substantially harder than the k-server problem, and prior to this work even for k = 3 taxis it has been unknown whether a finite competitive ratio is achievable on general metric spaces. We present an O(1)-competitive algorithm for the 3-taxi problem
Intermedial afterlives of the Arma Christi in Orlando Gibbons’s ‘See, See the Word is Incarnate’
No full textWe propose that Orlando Gibbons’s consort anthem ‘See, See the Word is Incarnate’ is linked to a wider phenomenon in visual culture surrounding the imagery of the instruments of Christ’s Passion, the arma Christi. Taking a bold interdisciplinary approach, we use close reading to show how this visual tradition manifested in intermedial ways. This case study is indicative of a type of exchange between art forms that was fundamental to English artistic practice and devotional experience. Our analysis connects this music to the Passion’s long history with sight, exploring broader contexts for Gibbons’s invocation to ‘see’. We view this song as an experiment in musical intermediality, exemplifying the fluidity between the visual, textual, and musical practices of early modern England. It expands current understanding of the piece’s connections to contemporary visual culture, while examining music’s potential as a potent act of extraordinary meditation within England’s complex post-Reformation confessional landscape