Keele University

About: Keele University is a education organization based out in Newcastle-under-Lyme, United Kingdom. It is known for research contribution in the topics: Population & Stars. The organization has 11318 authors who have published 26323 publications receiving 894671 citations. The organization is also known as: Keele University.

A Stubbornly Large Mass of Cold Dust in the Ejecta of Supernova 1987A

Abstract: We present new Herschel photometric and spectroscopic observations of Supernova 1987A, carried out in 2012. Our dedicated photometric measurements provide new 70 micron data and improved imaging quality at 100 and 160 micron compared to previous observations in 2010. Our Herschel spectra show only weak CO line emission, and provide an upper limit for the 63 micron [O I] line flux, eliminating the possibility that line contaminations distort the previously estimated dust mass. The far-infrared spectral energy distribution (SED) is well fitted by thermal emission from cold dust. The newly measured 70 micron flux constrains the dust temperature, limiting it to nearly a single temperature. The far-infrared emission can be fitted by 0.5+-0.1 Msun of amorphous carbon, about a factor of two larger than the current nucleosynthetic mass prediction for carbon. The observation of SiO molecules at early and late phases suggests that silicates may also have formed and we could fit the SED with a combination of 0.3 Msun of amorphous carbon and 0.5 Msun of silicates, totalling 0.8 Msun of dust. Our analysis thus supports the presence of a large dust reservoir in the ejecta of SN 1987A. The inferred dust mass suggests that supernovae can be an important source of dust in the interstellar medium, from local to high-redshift galaxies.

Direct transplantation of mesenchymal stem cells into the knee joints of Hartley strain guinea pigs with spontaneous osteoarthritis

Abstract: Introduction Mesenchymal stem cells (MSCs) can differentiate into various connective tissue cells. Several techniques have been used for the clinical application of MSCs in articular cartilage repair; however, there are many issues associated with the selection of the scaffold material, including its ability to support cell viability and differentiation and its retention and degradation in situ. The application of MSCs via a scaffold also requires a technically demanding surgical procedure. The aim of this study was to test the outcome of intra-articular transplantation of mesenchymal stem cells suspended in hyaluronic acid (HA) in the knee joints of Hartley strain guinea pigs with spontaneous osteoarthritis (OA).

Advanced burning stages and fate of 8-10 M⊙ STARS

Abstract: The stellar mass range 8 {approx}< M/M{sub Sun} {approx}< 12 corresponds to the most massive asymptotic giant branch (AGB) stars and the most numerous massive stars. It is host to a variety of supernova (SN) progenitors and is therefore very important for galactic chemical evolution and stellar population studies. In this paper, we study the transition from super-AGB (SAGB) star to massive star and find that a propagating neon-oxygen-burning shell is common to both the most massive electron capture supernova (EC-SN) progenitors and the lowest mass iron-core-collapse supernova (FeCCSN) progenitors. Of the models that ignite neon-burning off-center, the 9.5 M{sub Sun} star would evolve to an FeCCSN after the neon-burning shell propagates to the center, as in previous studies. The neon-burning shell in the 8.8 M{sub Sun} model, however, fails to reach the center as the URCA process and an extended (0.6 M{sub Sun }) region of low Y{sub e} (0.48) in the outer part of the core begin to dominate the late evolution; the model evolves to an EC-SN. This is the first study to follow the most massive EC-SN progenitors to collapse, representing an evolutionary path to EC-SN in addition to that from SAGB stars undergoing thermal pulsesmore » (TPs). We also present models of an 8.75 M{sub Sun} SAGB star through its entire TP phase until electron captures on {sup 20}Ne begin at its center and of a 12 M{sub Sun} star up to the iron core collapse. We discuss key uncertainties and how the different pathways to collapse affect the pre-SN structure. Finally, we compare our results to the observed neutron star mass distribution.« less

Spasticity, an impairment that is poorly defined and poorly measured

Abstract: Objective: To explore, following a literature review, whether there is a consistent definition and a unified assessment framework for the term `spasticity'. The congruence between the definitions of spasticity and the corresponding methods of measurement were also explored.Data sources: The search was performed on the electronic databases Web of Science, Science Direct and MEDLINE.Review methods: A systematic literature search of publications written in English between the years 1980 and 2006 was performed with the following keywords: spasticity and tone. The search was limited to the following keywords: stroke, hemiplegia, upper, hand and arm.Results: Two hundred and fifty references contributed to this review (190 clinical trials, 46 literature reviews, and 14 case reports). Seventy-eight used the Lance definition; 88 equated spasticity with increased muscle tone; 78 provided no definition; and six others used their own definitions for spasticity. Most papers used a single measure and some used more tha...

Inflammatory back pain in primary care

Abstract: Three-hundred-and-thirteen back pain sufferers completed a screening questionnaire for inflammatory back pain. This was positive in 46 (15%), who were invited for a further examination. Only two of these patients had definite ankylosing spondylitis. Eighteen of them (39%) had other features associated with spondyloarthropathy. It is suggested that up to 5% of back pain sufferers may have a mild form of ankylosing spondylitis that may never progress to definite ankylosis, but for whom treatment as if they had ankylosing spondylitis may be of benefit.