A large Wolf-Rayet population in NGC300 uncovered by VLT-FORS2

We have detected 58 Wolf-Rayet candidates in the central region of the nearby spiral galaxy NGC 300, based on deep VLT-FORS2 narrow-band imaging. Our survey is close to complete except for heavily reddened WR stars. Of the objects in our list, 16 stars were already spectroscopically confirmed as WR stars by Schild & Testor and Breysacher et al., to which 4 stars are added using low resolution FORS2 datasets. The WR population of NGC300 now totals 60,a threefold increase over previous surveys, with WC/WN>1/3, in reasonable agreement with Local Group galaxies for a moderately sub-solar metallicity. We also discuss the WR surface density in the central region of NGC 300. Finally, analyses are presented for two apparently single WC stars - #29 (alias WR3, WC5) and #48 (alias WR13, WC4) located close to the nucleus, and at a deprojected radius of 2.5 kpc, respectively. These are among the first models of WR stars in galaxies beyond the Local Group, and are compared with early WC stars in our Galaxy and LMC.Comment: 12 pages, 12 figures, submitted to A&A (includes aa.cls) - version with higher resolution finding charts available from ftp://ftp.star.ucl.ac.uk/pub/pac/ngc300.ps.g

Intractable difficulties in caring for people with Sickle Cell Disease

Bergman and Diamond (2013) have articulately and accurately identified many of the reasons why, and the problems associated with, the identification of people with sickle cell disease (SCD) as “difficult patients.” In our view, however, by suggesting that this problem is best dealt with through an ethics service consultation (ESC), they misconstrue the source of the difficulties of SCD and fail to appreciate the limitations of bioethics in seeking to improve the health care experience of people living with SCD. We provide empirical data describing an Australian perspective of SCD care, which highlights not only the complex issues raised by this illness but the challenges it creates for medical decision making and for bioethics. We suggest that the difficulties of SCD are protean in nature and that more can be gained from thinking again about the limits of bioethics and contemporary medicine than it can by seeking solace in clinical ethics consultation

Evolution of precipitates, in particular cruciform and cuboid particles, during simulated direct charging of thin slab cast vanadium microalloyed steels

A study has been undertaken of four vanadium based steels which have been processed by a simulated direct charging route using processing parameters typical of thin slab casting, where the cast product has a thickness of 50 to 80mm ( in this study 50 mm) and is fed directly to a furnace to equalise the microstructure prior to rolling. In the direct charging process, cooling rates are faster, equalisation times shorter and the amount of deformation introduced during rolling less than in conventional practice. Samples in this study were quenched after casting, after equalisation, after 4th rolling pass and after coiling, to follow the evolution of microstructure. The mechanical and toughness properties and the microstructural features might be expected to differ from equivalent steels, which have undergone conventional processing. The four low carbon steels (~0.06wt%) which were studied contained 0.1wt%V (V-N), 0.1wt%V and 0.010wt%Ti (V-Ti), 0.1wt%V and 0.03wt%Nb (V-Nb), and 0.1wt%V, 0.03wt%Nb and 0.007wt%Ti (V-Nb-Ti). Steels V-N and V-Ti contained around 0.02wt% N, while the other two contained about 0.01wt%N. The as-cast steels were heated at three equalising temperatures of 1050C, 1100C or 1200C and held for 30-60 minutes prior to rolling. Optical microscopy and analytical electron microscopy, including parallel electron energy loss spectroscopy (PEELS), were used to characterise the precipitates. In the as-cast condition, dendrites and plates were found. Cuboid particles were seen at this stage in Steel V-Ti, but they appeared only in the other steels after equalization. In addition, in the final product of all the steels, fine particles were seen, but it was only in the two titanium steels that cruciform precipitates were present. PEELS analysis showed that the dendrites, plates, cuboids, cruciforms and fine precipitates were essentially nitrides. The two Ti steels had better toughness than the other steels but inferior lower yield stress values. This was thought to be, in part, due to the formation of cruciform precipitates in austenite, thereby removing nitrogen and the microalloying elements which would have been expected to precipitate in ferrite as dispersion hardening particles

Intractable difficulties in caring for people with Sickle Cell Disease

Bergman and Diamond (2013) have articulately and accurately identified many of the reasons why, and the problems associated with, the identification of people with sickle cell disease (SCD) as “difficult patients.” In our view, however, by suggesting that this problem is best dealt with through an ethics service consultation (ESC), they misconstrue the source of the difficulties of SCD and fail to appreciate the limitations of bioethics in seeking to improve the health care experience of people living with SCD. We provide empirical data describing an Australian perspective of SCD care, which highlights not only the complex issues raised by this illness but the challenges it creates for medical decision making and for bioethics. We suggest that the difficulties of SCD are protean in nature and that more can be gained from thinking again about the limits of bioethics and contemporary medicine than it can by seeking solace in clinical ethics consultation

A Spectroscopic Search for the non-nuclear Wolf-Rayet Population of the metal-rich spiral galaxy M83

We present a catalogue of non-nuclear regions containing Wolf-Rayet stars in the metal-rich spiral galaxy M83 (NGC5236). From a total of 283 candidate regions identified using HeII 4686 imaging with VLT-FORS2, Multi Object Spectroscopy of 198 regions was carried out, confirming 132 WR sources. From this sub-sample, an exceptional content of 1035 +/- 300 WR stars is inferred, with N(WC)/N(WN) approx 1.2, continuing the trend to larger values at higher metallicity amongst Local Group galaxies, and greatly exceeding current evolutionary predictions at high metallicity. Late-type stars dominate the WC population of M83, with N(WC8-9)/N(WC4-7)=9 and WO subtypes absent, consistent with metallicity dependent WC winds. Equal numbers of late to early WN stars are observed, again in contrast to current evolutionary predictions. Several sources contain large numbers of WR stars. In particular, #74 (alias region 35 from De Vaucouleurs et al. contains 230 WR stars, and is identified as a Super Star Cluster from inspection of archival HST/ACS images. Omitting this starburst cluster would result in revised statistics of N(WC)/N(WN) approx 1 and N(WC8-9)/N(WC4-7) approx 6 for the `quiescent' disk population. Including recent results for the nucleus and accounting for incompleteness in our spectroscopic sample, we suspect the total WR population of M83 may exceed 3000 stars.Comment: 39 pages, 13 figures, 17 finding charts, accepted for Astronomy & Astrophysics. Version will full resolution images available at ftp://astro1.shef.ac.uk/pub/pac/m83.ps.g

Stimulation of bone growth with thrombin peptide derivatives

Disclosed is a method of stimulating bone growth at a site in a subject in need of osteoinduction. The method comprises the step of administering a therapeutically effective amount of an agonist of the non-proteolytically activated thrombin receptor to the site.Board of Regents, University of Texas Syste

Development and validation of a chemostat gut model to study both planktonic and biofilm modes of growth of Clostridium difficile and human microbiota

Copyright: 2014 Crowther et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.The human gastrointestinal tract harbours a complex microbial community which exist in planktonic and sessile form. The degree to which composition and function of faecal and mucosal microbiota differ remains unclear. We describe the development and characterisation of an in vitro human gut model, which can be used to facilitate the formation and longitudinal analysis of mature mixed species biofilms. This enables the investigation of the role of biofilms in Clostridium difficile infection (CDI). A well established and validated human gut model of simulated CDI was adapted to incorporate glass rods that create a solid-gaseous-liquid interface for biofilm formation. The continuous chemostat model was inoculated with a pooled human faecal emulsion and controlled to mimic colonic conditions in vivo. Planktonic and sessile bacterial populations were enumerated for up to 46 days. Biofilm consistently formed macroscopic structures on all glass rods over extended periods of time, providing a framework to sample and analyse biofilm structures independently. Whilst variation in biofilm biomass is evident between rods, populations of sessile bacterial groups (log10 cfu/g of biofilm) remain relatively consistent between rods at each sampling point. All bacterial groups enumerated within the planktonic communities were also present within biofilm structures. The planktonic mode of growth of C. difficile and gut microbiota closely reflected observations within the original gut model. However, distinct differences were observed in the behaviour of sessile and planktonic C. difficile populations, with C. difficile spores preferentially persisting within biofilm structures. The redesigned biofilm chemostat model has been validated for reproducible and consistent formation of mixed species intestinal biofilms. This model can be utilised for the analysis of sessile mixed species communities longitudinally, potentially providing information of the role of biofilms in CDI.Peer reviewe

EBM and Epistemological Imperialism: Narrowing the divide between evidence and illness

Evidence Based Medicine (EBM) is an approach to clinical practice that relies on the use of systematically reviewed published clinical research of high quality. Whilst there is some speculation as to whether a true consensus definition of EBM exists (Loughlin (2008)(1)), a commonly cited explanation “the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients’ (Sackett et al (1996)(2)). Most approaches to “EBM” incorporate the use of an evidence hierarchy that presupposes that some forms of evidence are better than others (Guyatt and Rennie (2002)(3)), that meta-analyses and randomised controlled trials (RCTs) will guide a better level of care than expert or local knowledge. Although EBM is pervasive throughout all health literature a number of ethical (Gupta (2009)(4)), epistemological (Loughlin (2008)(1)), and clinical practice critiques (Tobin (2008)(5)) have emerged. Criticisms of EBM on ethical grounds have previously been summarised by Kerridge (2010)(6) and include ; “that the implicit and explicit requirement for RCTs may lead to unnecessary research being done where sufficient evidence already exists;... that methods privileged by EBM, most notably the RCT, are methodologically unable to answer questions related to individual patients;.... that evidence hierarchies are inadequate and misleading;.... that the dataset that EBM draws from is systematically bias[ed],.... that the translation of evidence into practice through clinical practice guidelines and decision aids is both ethically and epistemologically problematic...[and] that evidence is not value-neutral and cannot be easily translated into practice.