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Testate amoebae are informative bioindicators of critically high ammonia deposition on peatlands
No full textThe global nitrogen cycle has been majorly disrupted by anthropogenic activity. While nitrogen emissions in the UK and Ireland are declining, ammonia (NH3) remains a significant exception. NH3 emissions are mostly agriculturally sourced and deposited on nearby habitats at high rates in both countries. Peatlands are globally important wetlands that are vulnerable to NH3 deposition. Essential peatland restoration risks being diminished by excessive NH3 deposition, leading to the loss of valuable ecosystem services. This study investigates testate amoebae (indicators of contemporary and historic peatland conditions) as bioindicators of seasonal NH3 deposition on six peatlands across Northern Ireland, UK. Sphagnum, an NH3-sensitive bryophyte, was sampled adjacent to NH3 monitoring sites once per season for a year. When NH3 deposition was critically high, multivariate analysis demonstrates a link between NH3 and testate amoebae assemblage change. Similarly, at high NH3 deposition sites, testate amoebae taxa diversity is observed to be significantly reduced in springtime, when it is expected to be highest. Although, in response to high NH3 deposition large algivorous taxa do not proliferate as was anticipated, and mixotrophic taxa abundance decreases could not be linked primarily to NH3. This research demonstrates the continued potential of testate amoebae as highly informative peatland bioindicators.</p
Contact-scale insights into the shear stiffness of non-spherical granular materials
No full textSmall-strain shear stiffness (G0) is an essential parameter to predict deformation characteristics and dynamic properties of granular materials. It is empirically known that G0 increases with decreasing a void ratio (e0) and increasing isotropic stress level (′0). Recently, the effect of particle shape on G0 has been studied; however, the mechanism underlying the evolution of G0 is not fully understood. Using the discrete element method (DEM), this contribution quantifies the G0 of granular materials by performing small-strain probing where multi-sphere clumped particles are used to vary particle shape and surface topology systematically. The Hertzian contact theory is applied for each sphere-element contact to capture the stress-dependent contact stiffness. The results reveal that G0 is well correlated with e0 or mean coordination number for a given particle shape; however, G0 is measurably reduced when finer sphere-elements dominate inter-particle contact responses. The present study proposes two contact-scale expressions of G0 for non-spherical particles based on contact area (CA) and micromechanical effective medium theory (EMT) by extending the EMT expression for spherical particles; both can capture the effects of particle shape and ′0 on G0 under given conditions where particle breakage does not occur
Dynamic complement protein changes in aqueous humor and plasma of patients with retinal vein occlusion during ranibizumab treatment
No full textPurpose: To assess dynamic changes of complement protein in aqueous humor (AH) and plasma of retinal vein occlusion (RVO) patients during ranibizumab treatment, and to explore the differential expression of complement proteins in branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO). Patients and Methods: This prospective, consecutive case series study collected AH and plasma samples from 27 RVO patients at baseline, 1 and 2 months after ranibizumab treatment, including 19 BRVO and 8 CRVO patients. The concentrations of 13 complement proteins and vascular endothelial growth factor A (VEGF-A) were measured using Luminex® × MAP® technology. Results: During ranibizumab treatment, a reduction in the levels of C1q (p < 0.001), C2 (p = 0.030), C4 (p = 0.001), C4b (p = 0.026), C3b/iC3b (p < 0.001), C5 (p = 0.007), C5a (p = 0.005), CFD (p = 0.022), CFH (p < 0.001), and CFI (p < 0.001) in AH was observed. No significant changes were observed in the plasma levels of all measured factors. At baseline, CRVO had higher levels of C4 (p = 0.003), C4b (p < 0.001), C3b/iC3b (p < 0.001), C5 (p = 0.020), C5a (p = 0.007), CFD (p = 0.002), CFH (p < 0.001), and CFI (p < 0.001) in AH compared to BRVO. Conclusion: Ranibizumab treatment reduced the intraocular but not circulating activation of classical and alternative complement pathways in RVO patients. Differences in intraocular complement proteins were observed between BRVO and CRVO patients, which may reflect different pathogenesis.</p
Insights and considerations for “Higher intraocular levels of inflammatory factors are related to retinal vascular and neurodegeneration in myopic retinopathy”
No full textPartisan politics, economic hardship, and full-time day care for children in German cities
No full textThe availability of full-time day care spots for children is important for integrating parents into the job market and for reducing the prominence of traditional role models within families. We argue that political parties with redistributive economic policy positions and progressive views on the order of society put more emphasis in establishing full-time day care places. We make use of an original dataset that covers information on the annual number of children in full-time day care places, which we use as an indicator of availability, in 108 German cities between 2006 and 2020. We find that – when controlling for the economic and political context of a city and for personal characteristics of the mayor – the number of full-time day care spots for children per capita in cities that face economic hardship is significantly lower, in particular if the mayor belongs to a left-wing party
SN 2023zaw: the low-energy explosion of an ultrastripped star
No full textMost stripped-envelope supernova progenitors are thought to be formed through binary interaction, losing hydrogen and/or helium from their outer layers. Ultrastripped supernovae are an emerging class of transient that are expected to be produced through envelope stripping by a neutron star companion. However, relatively few examples are known, and the outcomes of such systems can be diverse and are poorly understood at present. Here we present spectroscopic observations and high-cadence, multiband photometry of SN 2023zaw, a rapidly evolving supernova with a low ejecta mass. SN 2023zaw was discovered in a nearby spiral galaxy at D = 39.7 Mpc. It has significant Milky Way extinction, E(B − V)MW = 0.21, and significant (but uncertain) host extinction. Bayesian evidence comparison reveals that nickel is not the only power source and that an additional energy source is required to explain our observations. Our models suggest that an ejecta mass of Mej ∼ 0.07 M⊙ and a synthesised nickel mass of MNi ∼ 0.007 M⊙ are required to explain the observations. We find that additional heating from a central engine, or interaction with circumstellar material, can power the early light curve.<br/
Mutational profile dynamics in follicular lymphoma and large cell transformation
No full textAims: Follicular lymphoma (FL) is characterised by significant heterogeneity in both the clinical trajectories and the molecular profiles. This study aimed to investigate clonal dynamics in FL by analysing mutation profiles at various time points during the disease course including at histological transformation (HT), to gain insight into the mutational changes over time. Methods: We retrospectively analysed 76 biopsies from 25 patients, including 13 cases with three or more FL biopsies and 12 cases with subsequent HT. Hybrid capture-based Next-Generation Sequencing (NGS) with the EuroClonality-NGS DNA capture (EuroClonality-NDC) assay was used to examine clonal rearrangements and mutations. Results: A total of 204 (potentially) pathogenic mutations were identified. Only 40% of mutations remained stably present during a median follow-up period of 139 months (range 9-198). KMT2D and CREBBP were the most frequently mutated genes at diagnosis, exhibiting relative stability in follow-up biopsies. Conversely, EZH2 displayed a dynamic pattern of mutations gained and lost during the disease course. At HT, pathogenic mutations affecting B2M, MYC and TP53 emerged. Changes in mutational burden were observed in both FL-sequential and diagnosis-transformation cohorts, with more pronounced changes in the latter. Conclusions: This real-world study provides insights into the complex molecular pathogenesis of FL and HT. As targeted therapies emerge as treatment modalities, mutational profiles could influence treatment decisions in the future. Therefore, recognising the significant changes occurring in the mutational landscape of FL throughout the disease course is crucial.</p
Riverine barrier removals could proliferate biological invasions
No full textMultiple stressors, such as pollution, climate change, invasive species and fragmentation, threaten global ecosystems, requiring holistic management actions. Freshwater ecosystems are disproportionately biodiverse and particularly impacted by fragmentation and biological invasions. Artificial barriers, such as dams and weirs, are long-standing features of global landscapes, with a divergence of views on their benefits and disbenefits. Recognition of the negative impacts of barriers on the river continuum and native biota, particularly for migratory aquatic species, has led to a rapid rate of barrier removals in recent decades, especially in North America and Europe. However, since the rise in riverine barrier construction centuries ago, global biological invasion rates have concurrently surged. Artificial barriers can paradoxically slow the spread of invasive species through freshwaters, and barrier removal efforts thus risk proliferating invasive species that disperse rapidly through connected habitats. Despite well-intended plans for river restoration through barrier removals, the subsequent spread and colonisation of invasive species have been largely overlooked. This presents a ‘connectivity conundrum’: the removal of barriers intuitively addresses the issues of native species migrations and dispersals, but could perversely exacerbate the spread of invasive species. Basin-scale data collection around the short- and long-term impacts on invasive species will help to underpin future restoration projects and maximise the potential beneficial outcomes of barrier removals for native species
Unusual mechanism of aziridine biosynthesis catalysed by the αKG-dependent non-heme enzyme TqaL
No full textAziridines are present in many synthetic pharmaceuticals. The synthesis of the aziridine ring remains challenging due to its highly strained three-membered ring structure. Recently, a non-heme αKG-dependent enzyme, TqaL, has been demonstrated to catalyze the synthesis of aziridines from l-Val. However, the detailed reaction mechanism of the enzyme remains elusive. Herein, we reported, for the first time, the mechanism of oxidative cyclisation for aziridine synthesis catalyzed by TqaL. Following the HAA step, the reaction proceeded via a unique concerted process with a single electron transfer from the isopropyl radical to the Fe(iii)–OH motif, which was coupled with the electrophilic attack of the primary amine substrate on the tertiary isopropyl radical and simultaneous proton transfer from the substrate amine to the hydroxyl group of the Fe(iii)–OH to give the aziridine. This research would provide a valuable structural basis for tailoring the non-heme αKG-dependent enzyme for the biosynthesis of highly active aziridine derivatives as pharmaceuticals