163 research outputs found
Carbon nitride as a ligand: edge-site coordination of ReCl(CO)3-fragments to g-C3 N4
IR spectroscopy and model structural studies show binding of ReCl(CO) 3-fragments to carbon nitride (g-C 3N 4) occurs via κ 2 N,N′ bidentate coordination
Non-perturbative dynamics of hot non-Abelian gauge fields: beyond leading log approximation
Many aspects of high-temperature gauge theories, such as the electroweak
baryon number violation rate, color conductivity, and the hard gluon damping
rate, have previously been understood only at leading logarithmic order (that
is, neglecting effects suppressed only by an inverse logarithm of the gauge
coupling). We discuss how to systematically go beyond leading logarithmic order
in the analysis of physical quantities. Specifically, we extend to
next-to-leading-log order (NLLO) the simple leading-log effective theory due to
Bodeker that describes non-perturbative color physics in hot non-Abelian
plasmas. A suitable scaling analysis is used to show that no new operators
enter the effective theory at next-to-leading-log order. However, a NLLO
calculation of the color conductivity is required, and we report the resulting
value. Our NLLO result for the color conductivity can be trivially combined
with previous numerical work by G. Moore to yield a NLLO result for the hot
electroweak baryon number violation rate.Comment: 20 pages, 1 figur
Efficient photoelectrochemical Kolbe C-C coupling at BiVO4 electrodes under visible light irradiation
Electrochemical Kolbe C-C coupling of carboxylic acids at Pt electrodes has been studied for over 150 years and remains relevant today because renewable electricity is envisaged to make an increasing contribution to clean chemical processes and carboxylic acids are readily available precursors for chemical synthesis. Traditional electrochemical Kolbe occurs typically at very high potential (>10 V) which is required to achieve high selectivity for C-C coupling. Here we describe porous BiVO4 photoelectrodes that mediate C-C Kolbe coupling with near quantitative faradaic efficiency under visible light irradiation at <2 V. High substrate concentrations are also found to stabilise the double layer avoiding the need for additional supporting electrolyte. Comparison with related literature describing photocatalytic Kolbe C-C coupling shows that the apparent quantum yield can be raised from <1% to 12% demonstrating the distinct advantage of using photoelectrochemistry in this system
Single atom Cu(I) promoted mesoporous titanias for photocatalytic Methyl Orange depollution and H 2 production
Tailoring the physicochemical properties and hence reactivity of semiconductor photocatalysts in a predictable fashion, remains a challenge to their industrial application. Here we demonstrate the striking promotional effect of incorporating single Cu(I) atoms, on aqueous phase photocatalytic dye degradation and H2 production over surfactant-templated mesoporous TiO2. X-ray absorption spectroscopy reveals that ultra-low concentrations of copper (0.02-0.1 wt%) introduced into the mesoporous TiO2 surface create isolated Cu (I) species which suppress charge recombination, and confer a six-fold photocatalytic promotion of Methyl Orange degradation and four-fold enhancement of H2 evolution. The impact of mesopore structure and photophysical properties on photocatalytic activity is also quantified for the first time: calcination increases mesopore size and nanocrystalline order, and induces an anatase to rutile phase transition that is accompanied by a decrease in the optical band gap, increased charge carrier lifetime, and a concomitant significant activity enhancement
Quantification of water states in thin proton exchange membrane manufacturing using terahertz time-domain spectroscopy
Water states in proton exchange membranes have previously been extracted using terahertz time-domain spectroscopy (THz-TDS) for thick Nafion membranes. In this work, we have developed a parametric based algorithm for data analysis and applied it to thin industrially relevant membranes (13-70μm), processed under different conditions, producing results consistent with conventional gravimetric analysis and prior demonstrations. This therefore opens up opportunities for rapid membrane investigations and understanding
Pompon Dahlia‐like Cu2O/rGO Nanostructures for Visible Light Photocatalytic H2 Production and 4‐Chlorophenol Degradation
Hierarchical Cu2O nanospheres with a Pompon Dahlia‐like morphology were prepared by a one‐pot synthesis employing electrostatic self‐assembly. Nanocomposite analogues were also prepared in the presence of reduced graphene oxide (rGO). Photophysical properties of the hierarchical Cu2O nanospheres and Cu2O/rGO nanocomposite were determined, and their photocatalytic applications evaluated for photocatalytic 4‐chlorophenol (4‐CP) degradation and H2 production. Introduction of trace (6 h continuous reaction is observed
Non-randomised feasibility study testing a primary care intervention to promote engagement in an online health community for adults with troublesome asthma: protocol
Introduction: In the UK, approximately 4.3 million adults have asthma, with one-third experiencing poor asthma control, affecting their quality of life, and increasing their healthcare use. Interventions promoting emotional/behavioural self-management can improve asthma control and reduce comorbidities and mortality. Integration of online peer support into primary care services to foster self-management is a novel strategy. We aim to co-design and evaluate an intervention for primary care clinicians to promote engagement with an asthma online health community (OHC). Our protocol describes a ‘survey leading to a trial’ design as part of a mixed-methods, non-randomised feasibility study to test the feasibility and acceptability of the intervention. Methods and analysis: Adults on the asthma registers of six London general practices (~3000 patients) will be invited to an online survey, via text messages. The survey will collect data on attitudes towards seeking online peer support, asthma control, anxiety, depression, quality of life, information on the network of people providing support with asthma and demographics. Regression analyses of the survey data will identify correlates/predictors of attitudes/receptiveness towards online peer support. Patients with troublesome asthma, who (in the survey) expressed interest in online peer support, will be invited to receive the intervention, aiming to reach a recruitment target of 50 patients. Intervention will involve a one-off, face-to-face consultation with a practice clinician to introduce online peer support, sign patients up to an established asthma OHC, and encourage OHC engagement. Outcome measures will be collected at baseline and 3 months post intervention and analysed with primary care and OHC engagement data. Recruitment, intervention uptake, retention, collection of outcomes, and OHC engagement will be assessed. Interviews with clinicians and patients will explore experiences of the intervention. Ethics and dissemination: Ethical approval was obtained from a National Health Service Research Ethics Committee (reference: 22/NE/0182). Written consent will be obtained before intervention receipt and interview participation. Findings will be shared via dissemination to general practices, conference presentations and peer-reviewed publications. Trial registration number: NCT05829265
The Genome Sequence of Caenorhabditis briggsae: A Platform for Comparative Genomics
The soil nematodes Caenorhabditis briggsae and Caenorhabditis elegans diverged from a common ancestor roughly 100 million years ago and yet are almost indistinguishable by eye. They have the same chromosome number and genome sizes, and they occupy the same ecological niche. To explore the basis for this striking conservation of structure and function, we have sequenced the C. briggsae genome to a high-quality draft stage and compared it to the finished C. elegans sequence. We predict approximately 19,500 protein-coding genes in the C. briggsae genome, roughly the same as in C. elegans. Of these, 12,200 have clear C. elegans orthologs, a further 6,500 have one or more clearly detectable C. elegans homologs, and approximately 800 C. briggsae genes have no detectable matches in C. elegans. Almost all of the noncoding RNAs (ncRNAs) known are shared between the two species. The two genomes exhibit extensive colinearity, and the rate of divergence appears to be higher in the chromosomal arms than in the centers. Operons, a distinctive feature of C. elegans, are highly conserved in C. briggsae, with the arrangement of genes being preserved in 96% of cases. The difference in size between the C. briggsae (estimated at approximately 104 Mbp) and C. elegans (100.3 Mbp) genomes is almost entirely due to repetitive sequence, which accounts for 22.4% of the C. briggsae genome in contrast to 16.5% of the C. elegans genome. Few, if any, repeat families are shared, suggesting that most were acquired after the two species diverged or are undergoing rapid evolution. Coclustering the C. elegans and C. briggsae proteins reveals 2,169 protein families of two or more members. Most of these are shared between the two species, but some appear to be expanding or contracting, and there seem to be as many as several hundred novel C. briggsae gene families. The C. briggsae draft sequence will greatly improve the annotation of the C. elegans genome. Based on similarity to C. briggsae, we found strong evidence for 1,300 new C. elegans genes. In addition, comparisons of the two genomes will help to understand the evolutionary forces that mold nematode genomes
Genome-wide association study of eosinophilic granulomatosis with polyangiitis reveals genomic loci stratified by ANCA status
Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare inflammatory disease of unknown cause. 30% of patients have anti-neutrophil cytoplasmic antibodies (ANCA) specific for myeloperoxidase (MPO). Here, we describe a genome-wide association study in 676 EGPA cases and 6809 controls, that identifies 4 EGPA-associated loci through conventional case-control analysis, and 4 additional associations through a conditional false discovery rate approach. Many variants are also associated with asthma and six are associated with eosinophil count in the general population. Through Mendelian randomisation, we show that a primary tendency to eosinophilia contributes to EGPA susceptibility. Stratification by ANCA reveals that EGPA comprises two genetically and clinically distinct syndromes. MPO+\u2009ANCA EGPA is an eosinophilic autoimmune disease sharing certain clinical features and an HLA-DQ association with MPO+\u2009ANCA-associated vasculitis, while ANCA-negative EGPA may instead have a mucosal/barrier dysfunction origin. Four candidate genes are targets of therapies in development, supporting their exploration in EGPA
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