914 research outputs found

    Groundwater reinjection and heat dissipation: lessons from the operation of a large groundwater cooling system in Central London

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    The performance of a large open-loop groundwater cooling scheme in a shallow alluvial aquifer at a prominent public building in Central London has been monitored closely over its first 2 years of operation. The installed system provided cooling to the site continuously for a period of 9 months between June 2012 and April 2013. During this period, c. 131300 m3 of groundwater was abstracted from a single pumping well and recharged into a single injection borehole. The amount of heat rejected in this period amounts to c. 1.37 GWh. A programme of hydraulic testing was subsequently undertaken over a 3 month period between July and October 2013 to evaluate the performance of the injection borehole. The data indicate no significant change in injection performance between commissioning trials undertaken in 2010 and the most recent period of testing, as evidenced by comparison of injection pressures for given flow rates in 2010 and 2013. Continuous temperature monitoring of the abstracted water, the discharge and a number of observation wells demonstrates the evolution of a heat plume in the aquifer in response to heat rejection and subsequent dissipation of this heat during the 18 month planned cessation

    An extracellular transglutaminase is required for apple pollen tube growth

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    An extracellular form of the calcium-dependent protein-crosslinking enzyme TGase (transglutaminase) was demonstrated to be involved in the apical growth of Malus domestica pollen tube. Apple pollen TGase and its substrates were co-localized within aggregates on the pollen tube surface, as determined by indirect immunofluorescence staining and the in situ cross-linking of fluorescently labelled substrates. TGase-specific inhibitors and an anti-TGase monoclonal antibody blocked pollen tube growth, whereas incorporation of a recombinant fluorescent mammalian TGase substrate (histidine-tagged green fluorescent protein:His6– Xpr–GFP) into the growing tube wall enhanced tube length and germination, consistent with a role of TGase as a modulator of cell wall building and strengthening. The secreted pollen TGase catalysed the cross-linking of both PAs (polyamines) into proteins (released by the pollen tube) and His6-Xpr-GFP into endogenous or exogenously added substrates. A similar distribution of TGase activitywas observed in planta on pollen tubes germinating inside the style, consistent with a possible additional role for TGase in the interaction between the pollen tube and the style during fertilization

    Genetically engineered minipigs model the major clinical features of human neurofibromatosis type 1.

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    Neurofibromatosis Type 1 (NF1) is a genetic disease caused by mutations in Neurofibromin 1 (NF1). NF1 patients present with a variety of clinical manifestations and are predisposed to cancer development. Many NF1 animal models have been developed, yet none display the spectrum of disease seen in patients and the translational impact of these models has been limited. We describe a minipig model that exhibits clinical hallmarks of NF1, including café au lait macules, neurofibromas, and optic pathway glioma. Spontaneous loss of heterozygosity is observed in this model, a phenomenon also described in NF1 patients. Oral administration of a mitogen-activated protein kinase/extracellular signal-regulated kinase inhibitor suppresses Ras signaling. To our knowledge, this model provides an unprecedented opportunity to study the complex biology and natural history of NF1 and could prove indispensable for development of imaging methods, biomarkers, and evaluation of safety and efficacy of NF1-targeted therapies

    Evidence of sensory-driven behavior in the Ediacaran organism Parvancorina: Implications and autecological interpretations

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    © 2017 International Association for Gondwana Research. Published by Elsevier B.V.. This manuscript version is made available under the CC-BY-NC-ND 4.0 license: http://creativecommons.org/licenses/by-nc-nd/4.0/ This author accepted manuscript is made available following 12 month embargo from date of publication (Dec 2017) in accordance with the publisher’s archiving policyThe ancient in situ fossil seafloor communities of the Ediacara biota present an unparalleled window into the assembly of the earliest complex macroscopic organisms, including early animals on Earth ca. 555 million years ago (mya). The unique preservation style of Ediacara fossil seafloors preserves whole communities virtually ‘frozen in time’, including both living and dead organisms at the time of burial. This phenomenon, where the fossilized organisms are arranged as they were in life offers an unparalleled opportunity to examine ecological patterns in some of the earliest examples of animal communities in deep time. The small, anchor-shaped fossil genus Parvancorina is common among the Ediacara biota; however, its morphology and ecology have received little attention. Here, we describe a population of juvenile Parvancorina preserved on a section of fossil seafloor recently excavated from the characteristic Ediacara Member from Ediacara Conservation Park in the Flinders Ranges, South Australia. We applied spatial methods to the sample population of Parvancorina (n = 202) and found that they demonstrated two size-clusters, distinguishing juveniles from adults, and further analyses showed that the smaller specimens tended to be spatially aggregated. For the first time among any Ediacara taxon, we found that this sample population of Parvancorina demonstrated a strong bimodal orientation, suggesting that orientation played an important behavioral role in its autecology. The aggregated spatial distribution and bimodal orientation of Parvancorina likely resulted from behavioral responses to the influence of benthic currents, suggesting that Parvancorina had a complex sensory network, and was capable of motility

    Revealing the density of encoded functions in a viral RNA

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    Nikesh Patel, et al, ‘Revealing the density of encoded functions in a viral RNA’, Proceedings of the National Academy of Sciences of the United States of America (PNAS), Vol. 112 (7): 2227-2232, February 2015, doi: http:dx.doi.org/10. 1073/pnas.1420812112. This article is freely available online through the PNAS open access option.We present direct experimental evidence that assembly of a single-stranded RNA virus occurs via a packaging signal-mediated mechanism. We show that the sequences of coat protein recognition motifs within multiple, dispersed, putative RNA packaging signals, as well as their relative spacing within a genomic fragment, act collectively to influence the fidelity and yield of capsid self-assembly in vitro. These experiments confirm that the selective advantages for viral yield and encapsidation specificity, predicted from previous modeling of packaging signal-mediated assembly, are found in Nature. Regions of the genome that act as packaging signals also function in translational and transcriptional enhancement, as well as directly coding for the coat protein, highlighting the density of encoded functions within the viral RNA. Assembly and gene expression are therefore direct molecular competitors for different functional folds of the same RNA sequence. The strongest packaging signal in the test fragment, encodes a region of the coat protein that undergoes a conformational change upon contact with packaging signals. A similar phenomenon occurs in other RNA viruses for which packaging signals are known. These contacts hint at an even deeper density of encoded functions in viral RNA, which if confirmed, would have profound consequences for the evolution of this class of pathogensPeer reviewedFinal Published versio

    Longitudinal brain atrophy rates in transient ischemic attack and minor ischemic stroke patients and cognitive profiles

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    Introduction: Patients with transient ischemic attack (TIA) and minor stroke demonstrate cognitive impairment, and a four-fold risk of late-life dementia. Aim: To study the extent to which the rates of brain volume loss in TIA patients differ from healthy controls and how they are correlated with cognitive impairment. Methods: TIA or minor stroke patients were tested with a neuropsychological battery and underwent T1 weighted volumetric magnetic resonance imaging scans at fixed intervals over a 3 years period. Linear mixed effects regression models were used to compare brain atrophy rates between groups, and to determine the relationship between atrophy rates and cognitive function in TIA and minor stroke patients. Results: Whole brain atrophy rates were calculated for the TIA and minor stroke patients; n = 38 between 24 h and 18 months, and n = 68 participants between 18 and 36 months, and were compared to healthy controls. TIA and minor stroke patients demonstrated a significantly higher whole brain atrophy rate than healthy controls over a 3 years interval (p = 0.043). Diabetes (p = 0.012) independently predicted higher atrophy rate across groups. There was a relationship between higher rates of brain atrophy and processing speed (composite P = 0.047 and digit symbol coding P = 0.02), but there was no relationship with brain atrophy rates and memory or executive composite scores or individual cognitive tests for language (Boston naming, memory recall, verbal fluency or Trails A or B score). Conclusion: TIA and minor stroke patients experience a significantly higher rate of whole brain atrophy. In this cohort of TIA and minor stroke patients changes in brain volume over time precede cognitive decline

    A systematic review investigating fatigue, psychological and cognitive impairment following TIA and minor stroke:protocol paper

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    Approximately 20,000 people have a transient ischemic attack (TIA) and 23,375 have a minor stroke in England each year. Fatigue, psychological and cognitive impairments are well documented post-stroke. Evidence suggests that TIA and minor stroke patients also experience these impairments; however, they are not routinely offered relevant treatment. This systematic review aims to: (1) establish the prevalence of fatigue, anxiety, depression, post-traumatic stress disorder (PTSD) and cognitive impairment following TIA and minor stroke and to investigate the temporal course of these impairments; (2) explore impact on quality of life (QoL), change in emotions and return to work; (3) identify where further research is required and to potentially inform an intervention study

    ‘Sell[ing] what hasn’t got a name’: An exploration of the different understandings and definitions of ‘community engagement’ work in the performing arts

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    Widely known to promote broader involvement in the processes which define the arts and culture (Webster, 1997), community engagement work in the performing arts — despite employing a set of commonly recognised norms — has tended to be conceptualised differently both historically and contemporarily. Drawing on ethnographic research — particularly semi-structured qualitative interview accounts of numerous British practitioners with a track record of work in the sector, the article explores these different conceptualisations. The article finds that it is the actual ‘work that matters’ and not what it is named, and that the diversity of understandings and definitions among sectoral practitioners is reflective of evolving thinking, values and practice, something that may be destabilising for better or worse
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