131 research outputs found

    A Formal [4+4] Complementary Ambiphile Pairing (CAP) Reaction: A New Cyclization Pathway for ortho-Quinone Methides

    Get PDF
    A formal, one-pot, [4+4] cyclization pathway for the generation of 8-member sultams via in-situ generation of an ortho-quinone methide (o-QM) is reported. The pairing of ambiphilic synthons in a complementary fashion is examined whereby o-fluorobenzenesulfonamides are merged with in-situ-generated o-QM in a formal [4+4] cyclization pathway to afford 5,2,1-dibenzooxathiazocine-2,2-dioxide scaffolds under microwave (mW) conditions. The method reported represents the first use of an o-QM in a formal hetero [4+4] cyclization

    Scaling Out by Microwave-Assisted, Continuous Flow Organic Synthesis (MACOS): Multi-Gram Synthesis of Bromo- and Fluoro-benzofused Sultams Benzthiaoxazepine-1,1-dioxides

    Get PDF
    This is the peer reviewed version of the following article: Ullah, F., Samarakoon, T., Rolfe, A., Kurtz, R. D., Hanson, P. R., & Organ, M. G. (2010). Scaling Out by Microwave-Assisted, Continuous Flow Organic Synthesis (MACOS): Multi-Gram Synthesis of Bromo- and Fluoro-benzofused Sultams Benzthiaoxazepine-1,1-dioxides. Chemistry (Weinheim an Der Bergstrasse, Germany), 16(36), 10959–10962. http://doi.org/10.1002/chem.201001651, which has been published in final form at doi.org/10.1002/chem.201001651. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving

    Examining the Lived Experience of Mild Cognitive Impairment: An Evidence-Based Practice Project

    Get PDF
    This Evidence-Based Practice (EBP) project addressed the following question: What are the perspectives, experiences, and self-reports of adult individuals, groups, or populations who have MCI or report problems with Functional Cognition (and / or their caregivers)

    Monomer-on-Monomer (MoM) Mitsunobu Reaction: Facile Purification Utilizing Surface-Initiated Sequestration

    Get PDF
    A monomer-on-monomer (MoM) Mitsunobu reaction utilizing norbornenyl-tagged (Nb-tagged) reagents is reported, whereby purification was rapidly achieved by employing ring-opening metathesis polymerization which is initiated by any of three methods utilizing Grubbs catalyst (i) free catalyst in solution, (ii) surface-initiated catalyst-armed silica or (iii) surface-initiated catalyst-armed Co/C magnetic nanoparticles

    RADIAL VELOCITY MONITORING OFKEPLERHEARTBEAT STARS

    Get PDF
    Heartbeat stars (HB stars) are a class of eccentric binary stars with close periastron passages. The characteristic photometric HB signal evident in their light curves is produced by a combination of tidal distortion, heating, and Doppler boosting near orbital periastron. Many HB stars continue to oscillate after periastron and along the entire orbit, indicative of the tidal excitation of oscillation modes within one or both stars. These systems are among the most eccentric binaries known, and they constitute astrophysical laboratories for the study of tidal effects. We have undertaken a radial velocity (RV) monitoring campaign of Kepler HB stars in order to measure their orbits. We present our first results here, including a sample of 22 Kepler HB systems, where for 19 of them we obtained the Keplerian orbit and for 3 other systems we did not detect a statistically significant RV variability. Results presented here are based on 218 spectra obtained with the Keck/HIRES spectrograph during the 2015 Kepler observing season, and they have allowed us to obtain the largest sample of HB stars with orbits measured using a single instrument, which roughly doubles the number of HB stars with an RV measured orbit. The 19 systems measured here have orbital periods from 7 to 90 days and eccentricities from 0.2 to 0.9. We show that HB stars draw the upper envelope of the eccentricity–period distribution. Therefore, HB stars likely represent a population of stars currently undergoing high eccentricity migration via tidal orbital circularization, and they will allow for new tests of high eccentricity migration theories

    Comparative genomics reveals diversity among xanthomonads infecting tomato and pepper

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Bacterial spot of tomato and pepper is caused by four <it>Xanthomonas </it>species and is a major plant disease in warm humid climates. The four species are distinct from each other based on physiological and molecular characteristics. The genome sequence of strain 85-10, a member of one of the species, <it>Xanthomonas euvesicatoria </it>(<it>Xcv</it>) has been previously reported. To determine the relationship of the four species at the genome level and to investigate the molecular basis of their virulence and differing host ranges, draft genomic sequences of members of the other three species were determined and compared to strain 85-10.</p> <p>Results</p> <p>We sequenced the genomes of <it>X. vesicatoria </it>(<it>Xv</it>) strain 1111 (ATCC 35937), <it>X. perforans </it>(<it>Xp</it>) strain 91-118 and <it>X. gardneri </it>(<it>Xg</it>) strain 101 (ATCC 19865). The genomes were compared with each other and with the previously sequenced <it>Xcv </it>strain 85-10. In addition, the molecular features were predicted that may be required for pathogenicity including the type III secretion apparatus, type III effectors, other secretion systems, quorum sensing systems, adhesins, extracellular polysaccharide, and lipopolysaccharide determinants. Several novel type III effectors from <it>Xg </it>strain 101 and <it>Xv </it>strain 1111 genomes were computationally identified and their translocation was validated using a reporter gene assay. A homolog to Ax21, the elicitor of XA21-mediated resistance in rice, and a functional Ax21 sulfation system were identified in <it>Xcv</it>. Genes encoding proteins with functions mediated by type II and type IV secretion systems have also been compared, including enzymes involved in cell wall deconstruction, as contributors to pathogenicity.</p> <p>Conclusions</p> <p>Comparative genomic analyses revealed considerable diversity among bacterial spot pathogens, providing new insights into differences and similarities that may explain the diverse nature of these strains. Genes specific to pepper pathogens, such as the O-antigen of the lipopolysaccharide cluster, and genes unique to individual strains, such as novel type III effectors and bacteriocin genes, have been identified providing new clues for our understanding of pathogen virulence, aggressiveness, and host preference. These analyses will aid in efforts towards breeding for broad and durable resistance in economically important tomato and pepper cultivars.</p

    Localized Plasticity in the Streamlined Genomes of Vinyl Chloride Respiring Dehalococcoides

    Get PDF
    Vinyl chloride (VC) is a human carcinogen and widespread priority pollutant. Here we report the first, to our knowledge, complete genome sequences of microorganisms able to respire VC, Dehalococcoides sp. strains VS and BAV1. Notably, the respective VC reductase encoding genes, vcrAB and bvcAB, were found embedded in distinct genomic islands (GEIs) with different predicted integration sites, suggesting that these genes were acquired horizontally and independently by distinct mechanisms. A comparative analysis that included two previously sequenced Dehalococcoides genomes revealed a contextually conserved core that is interrupted by two high plasticity regions (HPRs) near the Ori. These HPRs contain the majority of GEIs and strain-specific genes identified in the four Dehalococcoides genomes, an elevated number of repeated elements including insertion sequences (IS), as well as 91 of 96 rdhAB, genes that putatively encode terminal reductases in organohalide respiration. Only three core rdhA orthologous groups were identified, and only one of these groups is supported by synteny. The low number of core rdhAB, contrasted with the high rdhAB numbers per genome (up to 36 in strain VS), as well as their colocalization with GEIs and other signatures for horizontal transfer, suggests that niche adaptation via organohalide respiration is a fundamental ecological strategy in Dehalococccoides. This adaptation has been exacted through multiple mechanisms of recombination that are mainly confined within HPRs of an otherwise remarkably stable, syntenic, streamlined genome among the smallest of any free-living microorganism

    Islet transplantation from a nationally funded UK centre reaches socially deprived groups and improves metabolic outcomes

    Get PDF
    Acknowledgements We thank the transplant nurses involved with the Scottish Islet Transplant Programme (T. McGilvray, J. Davidson, M. Phillips and C. Jansen) for help with participant assessment. We thank the Scottish National Blood Transfusion Services including the Histocompatibility and Immunogenetics Team for HLA typing and antibody screening, and the Tissue and Cells Team (A. Timpson, L. Fraser, L. Irvine and P. Henry) for islet isolation and product release testing. We acknowledge the Departments of Transplantation, Diabetes and Interventional Radiology at NHS Lothian for all aspects of patient care and the organ procurement programme. We thank J. Shaw and A. Brooks from the Department of Regenerative Medicine for Diabetes at the University of Newcastle for advice regarding CGMS. C-peptide assays were performed by the NIHR Cambridge Biomedical Research Centre, Core Biochemical Assay Laboratory. Funding: The Scottish Islet Transplant Programme is funded by the National Services Division. This research was funded by Diabetes UK (Biomedical and Psychosocial Outcomes of Islet Transplantation; Grant no. BDA 06/0003362), Diabetes Research and Wellness Foundation, Diabetes Foundation, Juvenile Diabetes Research Foundation and the Royal Infirmary Diabetes Treatment Trust Fund. Open Access: This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.Peer reviewedPublisher PD

    Novel Plasmids and Resistance Phenotypes in Yersinia pestis: Unique Plasmid Inventory of Strain Java 9 Mediates High Levels of Arsenic Resistance

    Get PDF
    Growing evidence suggests that the plasmid repertoire of Yersinia pestis is not restricted to the three classical virulence plasmids. The Java 9 strain of Y. pestis is a biovar Orientalis isolate obtained from a rat in Indonesia. Although it lacks the Y. pestis-specific plasmid pMT, which encodes the F1 capsule, it retains virulence in mouse and non-human primate animal models. While comparing diverse Y. pestis strains using subtractive hybridization, we identified sequences in Java 9 that were homologous to a Y. enterocolitica strain carrying the transposon Tn2502, which is known to encode arsenic resistance. Here we demonstrate that Java 9 exhibits high levels of arsenic and arsenite resistance mediated by a novel promiscuous class II transposon, named Tn2503. Arsenic resistance was self-transmissible from Java 9 to other Y. pestis strains via conjugation. Genomic analysis of the atypical plasmid inventory of Java 9 identified pCD and pPCP plasmids of atypical size and two previously uncharacterized cryptic plasmids. Unlike the Tn2502-mediated arsenic resistance encoded on the Y. enterocolitica virulence plasmid; the resistance loci in Java 9 are found on all four indigenous plasmids, including the two novel cryptic plasmids. This unique mobilome introduces more than 105 genes into the species gene pool. The majority of these are encoded by the two entirely novel self-transmissible plasmids, which show partial homology and synteny to other enterics. In contrast to the reductive evolution in Y. pestis, this study underlines the major impact of a dynamic mobilome and lateral acquisition in the genome evolution of the plague bacterium
    corecore