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[2.2]Paracyclophane-substituted chiral multiresonant thermally activated delayed fluorescence emitters for efficient organic light-emitting diodes
Get PDFThe authors aregrateful to the EPSRC for financial support (grant EP/W0151371/1and EP/W007517/1). Y.X. thanks the China Scholarship Council(202106310038) for support. J.S. thanks the Jürgen Manchot Foundation, the Karlsruhe School of Optics and Photonics, and Dr. Erik Strandberg and Bianca Posselt, for their help in ECD measurements.The authors thank the European Commission Research ExecutiveAgency (Grant Agreement number: 101073045−TADFsolutions−HORIZON-MSCA-2021-DN) and the EPSRC (EP/X026175/1) for financial support. The authors acknowledge the Ministère de l’EnseignementSupérieur et de la Recherche and the Centre National de la RechercheScientifique (CNRS).The study reports two pairs of chiral multi-resonant thermally activated delayed fluorescence (MR-TADF) materials PCP-DiKTa and Czp-DiKTa by decorating a known MR-TADF core, DiKTa , with different [2.2]paracyclophane (PCP) based planar chiral groups. PCP-DiKTa shows narrow sky-blue emission with a full width at half maximum (FWHM) of 44 nm, while the emission of Czp-DiKTa is slightly broader with a FWHM of 66 nm and redshifted. Both emitters show high photoluminescence quantum yields of 93 and 99% for PCP-DiKTa and Czp-DiKTa , respectively. Enantiomerically pure samples of both compounds show chiroptical properties in the ground state while only Czp-DiKTa exhibits chiroptical activity in the excited state, with dissymmetry factors (|gPL|) of 4 × 10−4. Organic light-emitting diodes (OLEDs) with PCP-DiKTa and Czp-DiKTa show maximum external quantum efficiencies (EQEmax) of 25.7 and 29.2%, with λEL of 489 and 518 nm, and FWHMs of 53 and 69 nm, respectively. These EQEmax values are higher than those of other reported devices employing PCP-based D-A type emitters. This work demonstrates that the PCP moiety is not only a powerful building block to develop planar chiral emitters but one that is compatible with the fabrication of high efficiency devices.Peer reviewe
The first spectroscopic IR reverberation programme on Mrk 509
Get PDFK.H. and J.V.H.S. acknowledge support from STFC grant ST/R000824/1.Near IR spectroscopic reverberation of Active Galactic Nuclei (AGN) potentially allows the infrared (IR) broad line region (BLR) to be reverberated alongside the disc and dust continua, while the spectra can also reveal details of dust astro-chemistry. Here, we describe results of a short pilot study (17 near-IR spectra over a 183 d period) for Mrk 509. The spectra give a luminosity-weighted dust radius of 〈Rd,lum〉 = 186 ± 4 light-days for blackbody (large grain dust), consistent with previous (photometric) reverberation campaigns, whereas carbon and silicate dust give much larger radii. We develop a method of calibrating spectral data in objects where the narrow lines are extended beyond the slit width. We demonstrate this by showing our resultant photometric band light curves are consistent with previous results, with a hot dust lag at >40 d in the K band, clearly different from the accretion disc response at <20 d in the z band. We place this limit of 40 d by demonstrating clearly that the modest variability that we do detect in the H and K band does not reverberate on time-scales of less than 40 d. We also extract the Pa β line light curve, and find a lag which is consistent with the optical BLR H β line of ∼70–90 d. This is important as direct imaging of the near-IR BLR is now possible in a few objects, so we need to understand its relation to the better studied optical BLR.Peer reviewe
JWST-MIRI spectroscopy of warm molecular emission and variability in the AS 209 disk
Get PDFFunding: F. M. has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement No. 101053020, project Dust2Planets). C.W. acknowledges financial support from the Science and Technology Facilities Council and UK Research and Innovation (grant numbers ST/X001016/1 and MR/T040726/1).We present MIRI Medium-resolution Spectrograph observations of the large, multi-gapped protoplanetary disk around the T Tauri star AS 209. The observations reveal hundreds of water vapor lines from 4.9–25.5 μm toward the inner ∼1 au in the disk, including the first detection of rovibrational water emission in this disk. The spectrum is dominated by hot (∼800 K) water vapor and OH gas, with only marginal detections of CO2, HCN, and a possible colder water vapor component. Using slab models with a detailed treatment of opacities and line overlap, we retrieve the column density, emitting area, and excitation temperature of water vapor and OH, and provide upper limits for the observable mass of other molecules. Compared to MIRI spectra of other T Tauri disks, the inner disk of AS 209 does not appear to be atypically depleted in CO2 nor HCN. Based on Spitzer Infrared Spectrograph observations, we further find evidence for molecular emission variability over a 10 yr baseline. Water, OH, and CO2 line luminosities have decreased by factors of 2–4 in the new MIRI epoch, yet there are minimal continuum emission variations. The origin of this variability is yet to be understood.Peer reviewe
HSD3B1 is an oxysterol 3β-hydroxysteroid dehydrogenase in human placenta
Get PDFFunding Information: This work was supported by funding from the Biological Sciences Research Council (BBSRC, grant nos. BB/I001735/1, BB/N015932/1 and BB/S019588/1 to W.J.G., BB/L001942/1 to Y.W.), and the European Union, through European Structural Funds (ESF), as part of the Welsh Government funded Academic Expertise for Business project (to W.J.G. and Y.W.). A.D. was supported via a KESS2 award with Markes International from the Welsh Government and European Social Fund. Work at the Oxford laboratory was supported by the LEAN network grant by the Leducq Foundation (U.O.). J.E.D. is supported by NIHR Oxford Biomedical Research Centre, Oxford, UK.Most biologically active oxysterols have a 3β-hydroxy-5-ene function in the ring system with an additional site of oxidation at C-7 or on the side-chain. In blood plasma oxysterols with a 7α-hydroxy group are also observed with the alternative 3-oxo-4-ene function in the ring system formed by ubiquitously expressed 3β-hydroxy-Δ 5 -C 27 -steroid oxidoreductase Δ 5 -isomerase, HSD3B7. However, oxysterols without a 7α-hydroxy group are not substrates for HSD3B7 and are not usually observed with the 3-oxo-4-ene function. Here we report the unexpected identification of oxysterols in plasma derived from umbilical cord blood and blood from pregnant women taken before delivery at 37+ weeks of gestation, of side-chain oxysterols with a 3-oxo-4-ene function but no 7α-hydroxy group. These 3-oxo-4-ene oxysterols were also identified in placenta, leading to the hypothesis that they may be formed by a previously unrecognized 3β-hydroxy-Δ 5 -C 27 -steroid oxidoreductase Δ 5 -isomerase activity of HSD3B1, an enzyme which is highly expressed in placenta. Proof-of-principle experiments confirmed that HSD3B1 has this activity. We speculate that HSD3B1 in placenta is the source of the unexpected 3-oxo-4-ene oxysterols in cord and pregnant women's plasma and may have a role in controlling the abundance of biologically active oxysterols delivered to the fetus.Peer reviewe
VerSoX B07‐B : a high‐throughput XPS and ambient pressure NEXAFS beamline at Diamond Light Source
Get PDFSLMS thanks the Royal Academy of Engineering, Diamond Light Source and Infineum UK Ltd for financial support of the Bragg Centenary Chair. DCG, PF, SK and GH thank the European Union Horizon 2020 research and innovation programme for funding (grant No. 101017928) (HYSOLCHEM).The beamline optics and endstations at branch B of the Versatile Soft X‐ray (VerSoX) beamline B07 at Diamond Light Source are described. B07‐B provides medium‐flux X‐rays in the range 45–2200 eV from a bending magnet source, giving access to local electronic structure for atoms of all elements from Li to Y. It has an endstation for high‐throughput X‐ray photoelectron spectroscopy (XPS) and near‐edge X‐ray absorption fine‐structure (NEXAFS) measurements under ultrahigh‐vacuum (UHV) conditions. B07‐B has a second endstation dedicated to NEXAFS at pressures from UHV to ambient pressure (1 atm). The combination of these endstations permits studies of a wide range of interfaces and materials. The beamline and endstation designs are discussed in detail, as well as their performance and the commissioning process.Peer reviewe
Modification of the resistive tearing instability with Joule heating by shear flow
Get PDFThis work was supported by funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program, Grant Agreement No. 833251 PROMINENT ERC-ADG 2018. J.D.J. acknowledges further funding by the UK's Science and Technology Facilities Council (STFC) Consolidated Grant No. ST/W001195/1. R.K. is further supported by Internal Funds KU Leuven through the Project No. C14/19/089 TRACESpace and an FWO Project No. G0B4521N.We investigate the influence of background shear flow on linear resistive tearing instabilities with Joule heating for two compressible plasma slab configurations: a Harris current sheet and a force-free, shearing magnetic field that varies its direction periodically throughout the slab, possibly resulting in multiple magnetic nullplanes. To do so, we exploit the latest version of the open-source, magnetohydrodynamic spectroscopy tool Legolas. Shear flow is shown to dramatically alter tearing behavior in the presence of multiple magnetic nullplanes, where the modes become propagating due to the flow. Finally, the tearing growth rate is studied as a function of resistivity, showing where it deviates from analytic scaling laws, as well as the Alfvén speed, the plasma-β, and the velocity parameters, revealing surprising nuance in whether the velocity acts stabilizing or destabilizing. We show how both slab setups can produce growth rate regimes, which deviate from analytic scaling laws, such that systematic numerical spectroscopic studies are truly necessary, for a complete understanding of linear tearing behavior in flowing plasmas.Peer reviewe
Experience of an anatomic femoral stem in a UK orthopaedic centre beyond 20 years of follow-up
No full textIntroduction Increasing interest in the use of anatomical stems has developed as the prevalence of periprosthetic fractures (PPFs) continues to increase. The primary aim of this study was to determine the long-term survivorship and PPF rate of an anatomical femoral stem in a single UK centre. Patients and methods Between 2000 and 2002, 94 consecutive THAs were performed using the 170 mm Lubinus SP II anatomical femoral stem in our institution. Patient demographics, operative details and clinical outcomes were collected prospectively in an arthroplasty database. Patient records and national radiographic archives were reviewed finally at a mean of 21.5 years (SD 0.7) following surgery to identify occurrence of subsequent revision surgery, dislocation or periprosthetic fracture. Results Mean patient age at surgery was 65.8 years (SD 12.5, 34–88 years). There were 48 women (51%). Osteoarthritis was the operative indication in 88 patients (94%). Analysis of all-cause THA failure demonstrated a survivorship of 98.5% (95% confidence interval [CI], 98.0–99.3%) at 10 years and 96.7% (94.5–98.9%) at 21 years. The 20-year stem survival for aseptic loosening was 100% with no cases of significant lysis found (lucent line > 2 mm) and no stems required revision. Patient demographics did not appear to influence risk of revision (p > 0.05). There were 2 revisions in total (2 for acetabular loosening with original stems retained). There were no PPFs identified at mean 21.5 year follow-up and 5 dislocations (5%). Conclusions The Lubinus SP II 170 mm stem demonstrated excellent survivorship and negligible PPF rates over 20 years following primary THA.Peer reviewe
Three major steps toward the conservation of freshwater and riparian biodiversity
Get PDFJ.M. and J.H. thank Stiftelsen Längmanska kulturfonden for funding travel to the conference. As.L. and K.R. thank the Estonian Research Council (grant 1121) for financial support, and A.M. acknowledges the Leverhulme Trust (RPG-2019-402). H.H. was supported by the European Union Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie Actions (grant agreement 860800): RIBES (river flow regulation, fish behaviour, and status), and V.A. acknowledges the support from the Leibniz Competition project Freshwater Megafauna Futures. E.J. received support through the National Laboratory for Health Security (RRF-2.3.1-21-2022-00006), Centre for Ecological Research, Budapest, Hungary, and thanks Z. Molnár for support.Freshwater ecosystems and their bordering wetlands and riparian zones are vital for human society and biological diversity. Yet, they are among the most degraded ecosystems, where sharp declines in biodiversity are driven by human activities, such as hydropower development, agriculture, forestry, and fisheries. Because freshwater ecosystems are characterized by strongly reciprocal linkages with surrounding landscapes, human activities that encroach on or degrade riparian zones ultimately lead to declines in freshwater–riparian ecosystem functioning. We synthesized results of a symposium on freshwater, riparian, and wetland processes and interactions and analyzed some of the major problems associated with improving freshwater and riparian research and management. Three distinct barriers are the lack of involvement of local people in conservation research and management, absence of adequate measurement of biodiversity in freshwater and riparian ecosystems, and separate legislation and policy on riparian and freshwater management. Based on our findings, we argue that freshwater and riparian research and conservation efforts should be integrated more explicitly. Best practices for overcoming the 3 major barriers to improved conservation include more and sustainable use of traditional and other forms of local ecological knowledge, choosing appropriate metrics for ecological research and monitoring of restoration efforts, and mirroring the close links between riparian and freshwater ecosystems in legislation and policy. Integrating these 3 angles in conservation science and practice will provide substantial benefits in addressing the freshwater biodiversity crisis.Peer reviewe
Doppler characteristics of sea clutter at K-band and W-band : results from the St Andrews and Coniston water trials
Get PDFFunding: UK Engineering and Physical Sciences Research Council under grant EP/S032851/1.This study reports on the experimental results from two field trials conducted by the University of St Andrews, focusing exclusively here on Doppler data. The first trial was at the Bruce Embankment in St Andrews, UK (winter 2020) and the second one was at Coniston Water in the Lake District, UK (autumn 2022). A 24 GHz K-band radar and a 94 GHz W-band radar were used in both trials to collect sea clutter data for phenomenology studies. As very few sea clutter data and analysis of these are available in the literature at these high frequencies, the results are expected to be of general interest within this field of study. The data collection at both trials was done for low grazing angles in the littoral zone. The datasets are quite varied in terms of wave direction, polarization and wind speed. The Doppler signatures and corresponding statistical parameters for these various conditions are reported here. The spectral analysis of different wave types (burst, whitecap, rough surface scattering) along with the combined spectra are also discussed. It is anticipated that these empirical results will be the precursor for improving upon the frequency ranges of existing sea clutter Doppler models
A political psychology of the link between populist beliefs and compliance with COVID-19 containment measures
Get PDFThis paper addresses the relationship between populist beliefs and compliance with COVID-19 containment measures. We argue that an understanding of this issue depends upon developing a social/political psychology which addresses the impact of social groups and social relations upon behavior. More specifically we propose that populist beliefs are based on the notion that elite authorities are opposed to the people and hence not to be trusted by them which in turn reduces compliance with what they propose. Furthermore, we draw distinctions between different domains of compliance (getting vaccinated, social distancing and complying with “track and trace”) and different forms of authority (politicians and scientists). We argue that, whereas loss of trust in politicians only undermines engagement with forms of compliance which involve direct engagement with political authority (i.e., track and trace) loss of trust in scientists undermines the very belief that there is a pandemic and hence reduces all forms of compliance. We use a survey of 321 English and Welsh respondents to address these arguments. The data provide weak support for the hypothesis that populism has an effect on compliance through trust in politicians but only in the case of participating in track and trace. The data provide stronger support for the hypothesis that populism has an effect on all forms of compliance through trust in scientists, but only when scientists are perceived as part of the elite. Over all these results demonstrate that the ability to understand the complex relationships between populist beliefs and compliance depends on developing a social/political psychology of COVID-19 which is able to explain how human behavior is shaped by social identities and social relationships which, in turn, are shaped by political ideologies.Peer reviewe
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