6,653 research outputs found

    Modelling the impact of prescribed global warming on runoff from headwater catchments of the Irrawaddy River and their implications for the water level regime of Loktak Lake, northeast India

    Get PDF
    Climate change is likely to have major implications for wetland ecosystems, which will include altered water level regimes due to modifications in local and catchment hydrology. However, substantial uncertainty exists in the precise impacts of climate change on wetlands due in part to uncertainty in GCM projections. This paper explores the impacts of climate change upon river discharge within three sub-catchments of Loktak Lake, an internationally important wetland in northeast India. This is achieved by running pattern-scaled GCM output through distributed hydrological models (developed using MIKE SHE) of each sub-catchment. The impacts of climate change upon water levels within Loktak Lake are subsequently investigated using a water balance model. Two groups of climate change scenarios are investigated. Group 1 uses results from seven different GCMs for an increase in global mean temperature of 2 A degrees C, the purported threshold of ''dangerous'' climate change, whilst Group 2 is based on results from the HadCM3 GCM for increases in global mean temperature between 1 A degrees C and 6 A degrees C. Results from the Group 1 scenarios show varying responses between the three sub-catchments. The majority of scenario-sub-catchment combinations (13 out of 21) indicate increases in discharge which vary from < 1% to 42% although, in some cases, discharge decreases by as much as 20%. Six of the GCMs suggest overall increases in river flow to Loktak Lake (2-27%) whilst the other results in a modest (6%) decline. In contrast, the Group 2 scenarios lead to an almost linear increase in total river flow to Loktak Lake with increasing temperature (up to 27% for 6 A degrees C), although two sub-catchments experience reductions in mean discharge for the smallest temperature increases. In all but one Group 1 scenario, and all the Group 2 scenarios, Loktak Lake water levels are higher, regularly reaching the top of a downstream hydropower barrage that impounds the lake and necessitating the release of water for barrage structural stability. Although elevated water levels may permit enhanced abstraction for irrigation and domestic uses, future increases in hydropower generation are limited by existing infrastructure. The higher water levels are likely to exacerbate existing ecological deterioration within the lake as well as enhancing problems of flooding of lakeside communities

    Enacting Productive Dialogue: Addressing the Challenge that Non-Human Cognition Poses to Collaborations Between Enactivism and Heideggerian Phenomenology

    Get PDF
    This chapter uses one particular proposal for interdisciplinary collaboration – in this case, between early Heideggerian phenomenology and enactivist cognitive science – as an example of how such partnerships may confront and negotiate tensions between the perspectives they bring together. The discussion begins by summarising some of the intersections that render Heideggerian and enactivist thought promising interlocutors for each other. It then moves on to explore how Heideggerian enactivism could respond to the challenge of reconciling the significant differences in the ways that each discourse seeks to apply the structures it claims to uncover

    VEGF<inf>111</inf>: New insights in tissue invasion

    Full text link
    © 2015 Danastas, Combes, Lindsay, Grau, Thompson and Murphy. Vascular endothelial growth factor is a secreted glycoprotein that acts on endothelial cells to induce developmental and physiological angiogenesis. It has also been implicated in angiogenesis occurring in several pathologies, most notably, cancer. Alternative splicing of VEGF mRNA transcripts results in several isoforms with distinct properties depending on their exon composition. Recently, a new isoform has been identified, VEGF111 with a unique exon composition responsible for its high angiogenic potential. In humans, the only known inducer of VEGF111 is DNA damage but its natural presence in the uterus of the viviparous lizard, Saiphos equalis, suggests other mechanisms of regulation. Most interestingly, the possible relationship between the evolution of viviparity and the associated increased risk in developing cancer may be important in understanding the mechanisms underlying tumor development

    5-HT3 Receptor Brain-Type B-Subunits are Differentially Expressed in Heterologous Systems.

    Get PDF
    Genes for five different 5-HT3 receptor subunits have been identified. Most of the subunits have multiple isoforms, but two isoforms of the B subunits, brain-type 1 (Br1) and brain-type 2 (Br2) are of particular interest as they appear to be abundantly expressed in human brain, where 5-HT3B subunit RNA consists of approximately 75% 5-HT3Br2, 24% 5-HT3Br1, and <1% 5-HT3B. Here we use two-electrode voltage-clamp, radioligand binding, fluorescence, whole cell, and single channel patch-clamp studies to characterize the roles of 5-HT3Br1 and 5-HT3Br2 subunits on function and pharmacology in heterologously expressed 5-HT3 receptors. The data show that the 5-HT3Br1 transcriptional variant, when coexpressed with 5-HT3A subunits, alters the EC50, nH, and single channel conductance of the 5-HT3 receptor, but has no effect on the potency of competitive antagonists; thus, 5-HT3ABr1 receptors have the same characteristics as 5-HT3AB receptors. There were some differences in the shapes of 5-HT3AB and 5-HT3ABr1 receptor responses, which were likely due to a greater proportion of homomeric 5-HT3A versus heteromeric 5-HT3ABr1 receptors in the latter, as expression of the 5-HT3Br1 compared to the 5-HT3B subunit is less efficient. Conversely, the 5-HT3Br2 subunit does not appear to form functional channels with the 5-HT3A subunit in either oocytes or HEK293 cells, and the role of this subunit is yet to be determined.Supported by grants from Universidad Nacional del Sur (UNS), Agencia Nacional de Promoción Científica y Tecnológica (ANPCYT), and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) to CB, and The Wellcome Trust (81925) and the MRC (MR/L021676) to SCRL.This is the final version of the article. It first appeared from the American Chemical Society via http://dx.doi.org/10.1021/acschemneuro.5b0008

    Fetal Sex and RHD Genotyping with Digital PCR Demonstrates Greater Sensitivity than Real-time PCR.

    Get PDF
    BACKGROUND: Noninvasive genotyping of fetal RHD (Rh blood group, D antigen) can prevent the unnecessary administration of prophylactic anti-D to women carrying RHD-negative fetuses. We evaluated laboratory methods for such genotyping. METHODS: Blood samples were collected in EDTA tubes and Streck® Cell-Free DNA™ blood collection tubes (Streck BCTs) from RHD-negative women (n = 46). Using Y-specific and RHD-specific targets, we investigated variation in the cell-free fetal DNA (cffDNA) fraction and determined the sensitivity achieved for optimal and suboptimal samples with a novel Droplet Digital™ PCR (ddPCR) platform compared with real-time quantitative PCR (qPCR). RESULTS: The cffDNA fraction was significantly larger for samples collected in Streck BCTs compared with samples collected in EDTA tubes (P < 0.001). In samples expressing optimal cffDNA fractions (≥4%), both qPCR and digital PCR (dPCR) showed 100% sensitivity for the TSPY1 (testis-specific protein, Y-linked 1) and RHD7 (RHD exon 7) assays. Although dPCR also had 100% sensitivity for RHD5 (RHD exon 5), qPCR had reduced sensitivity (83%) for this target. For samples expressing suboptimal cffDNA fractions (<2%), dPCR achieved 100% sensitivity for all assays, whereas qPCR achieved 100% sensitivity only for the TSPY1 (multicopy target) assay. CONCLUSIONS: qPCR was not found to be an effective tool for RHD genotyping in suboptimal samples (<2% cffDNA). However, when testing the same suboptimal samples on the same day by dPCR, 100% sensitivity was achieved for both fetal sex determination and RHD genotyping. Use of dPCR for identification of fetal specific markers can reduce the occurrence of false-negative and inconclusive results, particularly when samples express high levels of background maternal cell-free DNA

    Phenylalanine in the pore of the Erwinia ligand-gated ion channel modulates picrotoxinin potency but not receptor function.

    Get PDF
    The Erwinia ligand-gated ion channel (ELIC) is a bacterial homologue of eukaryotic Cys-loop ligand-gated ion channels. This protein has the potential to be a useful model for Cys-loop receptors but is unusual in that it has an aromatic residue (Phe) facing into the pore, leading to some predictions that this protein is incapable of ion flux. Subsequent studies have shown this is not the case, so here we probe the role of this residue by examining the function of the ELIC in cases in which the Phe has been substituted with a range of alternative amino acids, expressed in Xenopus oocytes and functionally examined. Most of the mutations have little effect on the GABA EC50, but the potency of the weak pore-blocking antagonist picrotoxinin at F16'A-, F16'D-, F16'S-, and F16'T-containing receptors was increased to levels comparable with those of Cys-loop receptors, suggesting that this antagonist can enter the pore only when residue 16' is small. T6'S has no effect on picrotoxinin potency when expressed alone but abolishes the increased potency when combined with F16'S, indicating that the inhibitor binds at position 6', as in Cys-loop receptors, if it can enter the pore. Overall, the data support the proposal that the ELIC pore is a good model for Cys-loop receptor pores if the role of F16' is taken into consideration.This project was supported by the Wellcome Trust Grant 81925 to S.C.R.L. S.C.R.L. is a Wellcome Trust Senior Research Fellow in Basic Biomedical Studies. M.A. is funded by a Yousef Jameel Scholarship. D.A.W. was funded by an MRC studentship.This is the final published version. It first appeared at http://pubs.acs.org/doi/abs/10.1021/bi5008035

    Identification of the protein kinases Pyk3 and Phg2 as regulators of the STATc-mediated response to hyperosmolarity

    Get PDF
    Cellular adaptation to changes in environmental osmolarity is crucial for cell survival. In Dictyostelium, STATc is a key regulator of the transcriptional response to hyperosmotic stress. Its phosphorylation and consequent activation is controlled by two signaling branches, one cGMP- and the other Ca(2+)-dependent, of which many signaling components have yet to be identified. The STATc stress signalling pathway feeds back on itself by upregulating the expression of STATc and STATc-regulated genes. Based on microarray studies we chose two tyrosine-kinase like proteins, Pyk3 and Phg2, as possible modulators of STATc phosphorylation and generated single and double knock-out mutants to them. Transcriptional regulation of STATc and STATc dependent genes was disturbed in pyk3(-), phg2(-), and pyk3(-)/phg2(-) cells. The absence of Pyk3 and/or Phg2 resulted in diminished or completely abolished increased transcription of STATc dependent genes in response to sorbitol, 8-Br-cGMP and the Ca(2+) liberator BHQ. Also, phospho-STATc levels were significantly reduced in pyk3(-) and phg2(-) cells and even further decreased in pyk3(-)/phg2(-) cells. The reduced phosphorylation was mirrored by a significant delay in nuclear translocation of GFP-STATc. The protein tyrosine phosphatase 3 (PTP3), which dephosphorylates and inhibits STATc, is inhibited by stress-induced phosphorylation on S448 and S747. Use of phosphoserine specific antibodies showed that Phg2 but not Pyk3 is involved in the phosphorylation of PTP3 on S747. In pull-down assays Phg2 and PTP3 interact directly, suggesting that Phg2 phosphorylates PTP3 on S747 in vivo. Phosphorylation of S448 was unchanged in phg2(-) cells. We show that Phg2 and an, as yet unknown, S448 protein kinase are responsible for PTP3 phosphorylation and hence its inhibition, and that Pyk3 is involved in the regulation of STATc by either directly or indirectly activating it. Our results add further complexities to the regulation of STATc, which presumably ensure its optimal activation in response to different environmental cues

    A pragmatic cluster randomised trial evaluating three implementation interventions

    Get PDF
    Background Implementation research is concerned with bridging the gap between evidence and practice through the study of methods to promote the uptake of research into routine practice. Good quality evidence has been summarised into guideline recommendations to show that peri-operative fasting times could be considerably shorter than patients currently experience. The objective of this trial was to evaluate the effectiveness of three strategies for the implementation of recommendations about peri-operative fasting. Methods A pragmatic cluster randomised trial underpinned by the PARIHS framework was conducted during 2006 to 2009 with a national sample of UK hospitals using time series with mixed methods process evaluation and cost analysis. Hospitals were randomised to one of three interventions: standard dissemination (SD) of a guideline package, SD plus a web-based resource championed by an opinion leader, and SD plus plan-do-study-act (PDSA). The primary outcome was duration of fluid fast prior to induction of anaesthesia. Secondary outcomes included duration of food fast, patients' experiences, and stakeholders' experiences of implementation, including influences. ANOVA was used to test differences over time and interventions. Results Nineteen acute NHS hospitals participated. Across timepoints, 3,505 duration of fasting observations were recorded. No significant effect of the interventions was observed for either fluid or food fasting times. The effect size was 0.33 for the web-based intervention compared to SD alone for the change in fluid fasting and was 0.12 for PDSA compared to SD alone. The process evaluation showed different types of impact, including changes to practices, policies, and attitudes. A rich picture of the implementation challenges emerged, including inter-professional tensions and a lack of clarity for decision-making authority and responsibility. Conclusions This was a large, complex study and one of the first national randomised controlled trials conducted within acute care in implementation research. The evidence base for fasting practice was accepted by those participating in this study and the messages from it simple; however, implementation and practical challenges influenced the interventions' impact. A set of conditions for implementation emerges from the findings of this study, which are presented as theoretically transferable propositions that have international relevance. Trial registration ISRCTN18046709 - Peri-operative Implementation Study Evaluation (POISE
    corecore