438 research outputs found

    Ostracods from freshwater and brackish environments of the Carboniferous of the Midland Valley of Scotland : the early colonization of terrestrial water bodies

    Get PDF
    The Mississippian Strathclyde Group of the Midland Valley of Scotland yields some of the earliest non-marine ostracods. The succession records shallow marine, deltaic, estuarine, lagoonal, lacustrine, fluvial and swamp environments representing a series of staging-posts between fully marine and limnetic settings. Macrofossils and ostracods are assigned to marine, marginal marine, brackish and freshwater environments based on their faunal assemblage patterns. Key brackish to freshwater ostracods are Geisina arcuata, Paraparchites circularis n. sp., Shemonaella ornata n. sp. and Silenites sp. A, associated with the bivalves Anthraconaia, Carbonicola, Cardiopteridium, Curvirimula, Naiadites, the microconchid ‘Spirorbis’, Spinicaudata and fish. Many Platycopina and Paraparchiticopina ostracods are interpreted as euryhaline, which corresponds with their occurrence in marine to coastal plain water bodies, and supports the ‘estuary effect’ hypothesis of non-marine colonization. The success of non-marine colonization by ostracods was dependent on the intrinsic adaptations of ostracod species to lower salinities, such as new reproductive strategies and the timing of extrinsic mechanisms to drive non-marine colonization, such as sea-level change. The genus Carbonita is the oldest and most common freshwater ostracod, and went on to dominate freshwater environments in the Late Palaeozoic

    Observation of the Curie Transition in Palladium Bionanomaterial Using Muon Spin Rotation Spectroscopy

    Get PDF
    Palladium bionanomaterial was manufactured using the sulfate-reducing bacterium, Desulfovibrio desulfuricans, to reduce soluble Pd(II) ions to cell-bound Pd(0). The material was examined using a Superconducting Quantum Interference Device (SQUID) to observe bulk magnetisation over the temperature range 10 – 300 K and by Muon Spin Rotation (μSR), which is a probe of the local magnetic environment inside the sample, over the temperature range 200 – 700 K. Results from SQUID were used to model the temperature dependence of ferromagnetic and paramagnetic components of the bulk magnetisation and, by extrapolation, to predict the Curie transition temperature. Results from μSR confirmed the accuracy of the prediction to within 20 K. The Curie transition, which started at 528 K, was shown to be spread over a wide ( 100 K) range. This was attributed to dependence of the transition on particle size and the range of particle sizes in the population. A competing contribution to the overall magnetisation was observed due to partial thermal decomposition of the organic component of the material. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3533

    Seasonal occurrence of balanomorph barnacle nauplius larvae in the region of the Antarctic Peninsula

    Get PDF
    Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Journal of Experimental Marine Biology and Ecology 392 (2010): 125-128, doi:10.1016/j.jembe.2010.04.016.Plankton samples taken along the west coast of the Antarctic Peninsula and in Bransfield Strait show widespread occurrence of Bathylasma corolliforme nauplius larvae during the austral spring, mid-October to the third week of December. During autumn, between the first week of May and early June there was a complete absence of balanomorph nauplii. This evidence shows periodicity in reproduction. There is a seemingly close correlation between the presence of these nauplii and the published data on phytoplankton biomass and seawater surface temperature.The research was supported by grants from the U.S. National Science Foundation Office of Polar Programs

    Linking energy sensing to suppression of JAK-STAT signalling: a potential route for repurposing AMPK activators?

    Get PDF
    YesExaggerated Janus kinase-signal transducer and activator of transcription (JAKSTAT) signalling is key to the pathogenesis of pro-inflammatory disorders, such as rheumatoid arthritis and cardiovascular diseases. Mutational activation of JAKs is also responsible for several haematological malignancies, including myeloproliferative neoplasms and acute lymphoblastic leukaemia. Accumulating evidence links adenosine 5′-monophosphate (AMP)–activated protein kinase (AMPK), an energy sensor and regulator of organismal and cellular metabolism, with the suppression of immune and inflammatory processes. Recent studies have shown that activation of AMPK can limit JAK-STAT-dependent signalling pathways via several mechanisms. These novel findings support AMPK activation as a strategy for management of an array of disorders characterised by hyper-activation of the JAKSTAT pathway. This review discusses the pivotal role of JAK-STAT signalling in a range of disorders and how both established clinically used and novel AMPK activators might be used to treat these conditions.British Heart Foundation; Diabetes UK; Chief Scientist Office; NHS Greater Glasgow and Clyde Research Endowment Fund; Chest, Heart and Stroke Scotlan

    Competition between Fusion and Quasi-fission in the Formation of Super-heavy Elements

    Get PDF
    Quasifission is a non-equilibrium dynamical process resulting in rapid separation of the dinuclear system initially formed after capture and sticking of two colliding heavy nuclei. This can inhibit fusion by many orders of magnitude, thus suppressing the cross section for formation of superheavy elements. Measurements with projectiles from C to Ni, made at the Australian National University Heavy Ion Accelerator Facility, have mapped out quasifission characteristics and systematics using mass-angle distributions (MAD) - the fission mass-split as a function of centre-of-mass angle. These provide information on quasifission dynamics in the least model-dependent way. Quasifission time-scale information in the MAD has been compared with TDHF calculations of the collisions, with good agreement being found. Most significantly, the nuclear structure of the two colliding nuclei has a dramatic effect on quasifission probabilities and characteristics in gentle collisions at near-barrier energies. The effect of static deformation alignment, closed shells and N/Z matching can completely change reaction outcomes. The realization of this strong dependence makes modelling quasifission and superheavy element formation a challenging task, but should ultimately allow more reliable prediction of superheavy element formation cross sections

    Postnatal development of intestinal immune system in piglets: implications for the process of weaning

    Get PDF
    European-wide directives are in place to establish a sustainable production of pigs without using production enhancers and chemotherapeutics. Thus, an economically-viable pig production is now only possible when the physiological mechanisms of defense against pathogens and tolerance against nutrients and commensal bacteria in the intestinal immune system are taken into account. During the postnatal period the piglet is facing first the time large amounts of new antigens and at weaning a second wave of nutritional antigens is entering the intestinal tract. The appropriate development of humoral and cellular functions of the intestinal immune system is essential for optimum growth and performance of the piglets. The integrity of the intestinal surfaces is a prerequisite of intestinal immunity and tolerance. Secretory IgA serves to exclude harmful antigens from uptake. The induction of intestinal immune reactions starts with antigen presentation by professional antigen presenting cells of Peyer's patches and mesenteric lymph nodes. In addition, the intestinal lamina propria serves as a mucosal compartment for regulation of immune responses. Here especially T regulatory cells (CD4(+) CD25(+)) have their function for maintaining intestinal homeostasis. The network of mucosal T and B cells develops after birth in a programmed sequence; it is almost completed at week 7 after birth. Weaning is associated with changes in the regulation of the lymphoid cells in the mucosa. In small and large intestine increases in pro- and anti-inflammatory cytokines were observed after weaning in lymphocytes. Epithelial cells were studied both in intestinal samples and in vitro. Here the cytokine patterns provide evidence that weaning is inducing a transient inflammation of the mucosa. Piglets weaned under conventional conditions have a thicker mucosa than pigs weaned from isolators. Cells of isolator-reared pigs show slightly higher levels of activation markers - probably reflecting the interaction of the foreign protein derived from bovine milk. The results presented in this overview demonstrate that further effort is necessary to elucidate the function of the porcine intestinal immune system in the postnatal period and at the time of weaning to provide criteria for porcine intestinal health

    Significant out-of-sample classification from methylation profile scoring for amyotrophic lateral sclerosis

    Get PDF
    We conducted DNA methylation association analyses using Illumina 450K data from whole blood for an Australian amyotrophic lateral sclerosis (ALS) case–control cohort (782 cases and 613 controls). Analyses used mixed linear models as implemented in the OSCA software. We found a significantly higher proportion of neutrophils in cases compared to controls which replicated in an independent cohort from the Netherlands (1159 cases and 637 controls). The OSCA MOMENT linear mixed model has been shown in simulations to best account for confounders. When combined in a methylation profile score, the 25 most-associated probes identified by MOMENT significantly classified case–control status in the Netherlands sample (area under the curve, AUC = 0.65, CI95% = [0.62–0.68], p = 8.3 × 10−22). The maximum AUC achieved was 0.69 (CI95% = [0.66–0.71], p = 4.3 × 10−34) when cell-type proportion was included in the predictor

    Metabolic diagnosis and medical prevention of calcium nephrolithiasis and its systemic manifestations: a consensus statement

    Get PDF
    Background: Recently published guidelines on the medical management of renal stone disease did not address relevant topics in the field of idiopathic calcium nephrolithiasis, which are important also for clinical research. Design: A steering committee identified 27 questions, which were proposed to a faculty of 44 experts in nephrolithiasis and allied fields. A systematic review of the literature was conducted and 5216 potentially relevant articles were selected; from these, 407 articles were deemed to provide useful scientific information. The Faculty, divided into working groups, analysed the relevant literature. Preliminary statements developed by each group were exhaustively discussed in plenary sessions and approved. Results: Statements were developed to inform clinicians on the identification of secondary forms of calcium nephrolithiasis and systemic complications; on the definition of idiopathic calcium nephrolithiasis; on the use of urinary tests of crystallization and of surgical observations during stone treatment in the management of these patients; on the identification of patients warranting preventive measures; on the role of fluid and nutritional measures and of drugs to prevent recurrent episodes of stones; and finally, on the cooperation between the urologist and nephrologist in the renal stone patients. Conclusions: This document has addressed idiopathic calcium nephrolithiasis from the perspective of a disease that can associate with systemic disorders, emphasizing the interplay needed between urologists and nephrologists. It is complementary to the American Urological Association and European Association of Urology guidelines. Future areas for research are identified
    corecore