1,324 research outputs found
Chemistry and the environment
A report on three symposia in the āEnergy, Water and Environmental Scienceā programme at the International Union of Pure and Applied Chemistry (IUPAC) 46th World Chemistry Congress (in Sao Paulo, Brazil, 9-14 July, 2017). The symposia presented the latest advances concerning the environmental impact of emerging technologies and the fate of pollutants in the environment
P01.29. Pre-polarization conductance at Jing-Well acupoints on the hand is correlated with blood flow measured by laser doppler flowmetry
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PPARĪ³ agonists negatively regulate Ī±IIbĪ²3 integrin outside-in signalling and platelet function through upregulation of protein kinase A activity
BACKGROUND:
Agonists for the peroxisome proliferator activated receptor PPARĪ³, have been shown to have inhibitory effects on platelet activity following stimulation by GPVI and GPCR agonists.
OBJECTIVES:
Profound effects on thrombus formation led us to suspect a role for PPARĪ³ agonists in the regulation of integrin Ī±IIbĪ²3 mediated signalling. Both GPVI and GPCR signalling pathways lead to Ī±IIbĪ²3 activation, and signalling through Ī±IIbĪ²3 plays a critical role in platelet function and normal haemostasis.
METHODS:
The effects of PPARĪ³ agonists on the regulation of Ī±IIbĪ²3 outside-in signalling was determined by monitoring the ability of platelets to adhere and spread on fibrinogen and undergo clot retraction. Effects on signalling components downstream of Ī±IIbĪ²3 activation were also determined following adhesion to fibrinogen by western blotting.
RESULTS:
Treatment of platelets with PPARĪ³ agonists inhibited platelet adhesion and spreading on fibrinogen and diminished clot retraction. A reduction in phosphorylation of several components of Ī±IIbĪ²3 signalling, including the integrin Ī²3 subunit, Syk, PLCĪ³2, FAK and Akt was also observed as a result of reduced interaction of the integrin Ī²3 subunit with GĪ±13. Studies of VASP phosphorylation revealed that this was a due to an increase in PKA activity following treatment with PPARĪ³ receptor agonists.
CONCLUSIONS:
This study provides further evidence for anti-platelet actions of PPARĪ³ agonists, identifies a negative regulatory role for PPARĪ³ agonists in the control of integrin Ī±IIbĪ²3 outside-in signalling, and provides a molecular basis by which the PPARĪ³ agonists negatively regulate platelet activation and thrombus formation
Quantification of bedform dynamics and bedload sediment flux in sandy braided rivers from airborne and satellite imagery
āÆThis is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordāÆImages from speciallyācommissioned aeroplane sorties (manned aerial vehicle, MAV), repeat unmanned aerial vehicles (UAVs) surveys, and Planet CubeSat satellites are used to quantify dune and bar dynamics in the sandy braided South Saskatchewan River, Canada. StructureāfromāMotion (SfM) techniques and application of a depthābrightness model are used to produce a series of Digital Surface Models (DSMs) at low and nearābankfull flows. A number of technical and image processing challenges are described that arise from the application of SfM in dry and submerged environments. A model for best practice is outlined and analysis suggests a depthābrightness model approach can represent the different scales of bedforms present in sandy braided rivers with lowāturbidity and shallow (< 2 m deep) water.
The aerial imagery is used to quantify the spatial distribution of unit bar and dune migration rate in an 18 km reach and three ~1 km long reaches respectively. Dune and unit bar migration rates are highly variable in response to local variations in planform morphology. Sediment transport rates for dunes and unit bars, obtained by integrating migration rates (from UAV) with the volume of sediment moved (from DSMs using MAV imagery) show nearāequivalence in sediment flux. Hence, reachābased sediment transport rate estimates can be derived from unit bar data alone. Moreover, it is shown that reasonable estimates of sediment transport rate can be made using just unit bar migration rates as measured from 2D imagery, including from satellite images, so long as informed assumptions are made regarding average bar shape and height. With recent availability of frequent, repeat satellite imagery, and the ease of undertaking repeat MAV and UAV surveys, for the first time, it may be possible to provide global estimates of bedload sediment flux for large or inaccessible lowāturbidity rivers that currently have sparse information on bedload sediment transport rates.Natural Environment Research Council (NERC
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RXR ligands negatively regulate thrombosis and hemostasis
OBJECTIVE: Platelets have been found to express intracellular nuclear receptors including the Retinoid X receptors (RXRĪ± and RXRĪ²). Treatment of platelets with ligands of RXR has been shown to inhibit platelet responses to ADP and thromboxane A2, however the effects on responses to other platelet agonists as well as the underlying mechanism has not been fully characterised.
APPROACH AND RESULTS: The effect of 9-cis-retinoic acid (9-cis-RA), docosahexaenoic acid and synthetic ligand for RXR, methoprene acid on collagen receptor (GPVI) agonists and Thrombin stimulated platelet function; including aggregation, granule secretion, integrin activation, calcium mobilisation, integrin Ī±IIbĪ²3 outside-in signalling and thrombus formation in vitro and in vivo were determined. Treatment of platelets with RXR ligands resulted in attenuation of platelet functional responses following stimulation by GPVI agonists and thrombin and inhibition of integrin Ī±IIbĪ²3 outside-in signalling. Treatment with 9-cis-RA caused inhibition of thrombus formation in vitro and an impairment of thrombosis and haemostasis in vivo. Both RXR ligands stimulated protein kinase A activation, measured by VASP S157 phosphorylation, that was found to be dependent on both cAMP and NFĪŗB activity.
CONCLUSIONS: This study identifies a widespread, negative regulatory role for RXR in the regulation of platelet functional responses and thrombus formation and describes novel events that lead to the upregulation of PKA, a known negative regulator of many aspects of platelet function. This mechanism may offer a possible explanation for the cardioprotective effects described in vivo following treatment with RXR ligands
Recent trend reversal for declining European seagrass meadows
Seagrass meadows, key ecosystems supporting fisheries, carbon sequestration and coastal
protection, are globally threatened. In Europe, loss and recovery of seagrasses are reported,
but the changes in extent and density at the continental scale remain unclear. Here we collate
assessments of changes from 1869 to 2016 and show that 1/3 of European seagrass area was
lost due to disease, deteriorated water quality, and coastal development, with losses peaking
in the 1970s and 1980s. Since then, loss rates slowed down for most of the species and fastgrowing
species recovered in some locations, making the net rate of change in seagrass area
experience a reversal in the 2000s, while density metrics improved or remained stable in
most sites. Our results demonstrate that decline is not the generalised state among seagrasses
nowadays in Europe, in contrast with global assessments, and that deceleration and
reversal of declining trends is possible, expectingly bringing back the services they provide
Hobsonās choice? Constraints on accessing spaces of creative production
Successful creative production is often documented to occur in urban areas that are more likely to be diverse, a source of human capital and the site of dense interactions. These accounts chart how, historically, creative industries have clustered in areas where space was once cheap in the city centre fringe and inner city areas, often leading to the development of a creative milieu, and thereby stimulating further creative production. Historical accounts of the development of creative areas demonstrate the crucial role of accessible low-cost business premises. This article reports on the findings of a case study that investigated the location decisions of firms in selected creative industry sectors in Greater Manchester. The study found that, while creative activity remains highly concentrated in the city centre, creative space there is being squeezed and some creative production is decentralizing in order to access cheaper premises. The article argues that the location choices of creative industry firms are being constrained by the extensive city centre regeneration, with the most vulnerable firms, notably the smallest and youngest, facing a Hobsonās choice of being able to access low-cost premises only in the periphery. This disrupts the delicate balance needed to sustain production and begs the broader question as to how the creative economy fits into the existing urban fabric, alongside the competing demands placed on space within a transforming industrial conurbation
Single-cell analyses reveal transient retinal progenitor cells in the ciliary margin of developing human retina
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