951 research outputs found

    Highly effective yet simple transmembrane anion transporters based upon ortho-phenylenediamine bis-ureas

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    Simple, highly fluorinated receptors are shown to function as highly effective transmembrane anion antiporters with the most active transporters rivalling the transport efficacy of natural anion transporter prodigiosin for bicarbonate

    Double-Crested Cormorant Colony Effects on Soil Chemistry, Vegetation Structure and Avian Diversity in a Southeastern Reservoir System

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    Ornithogenic material delivered by Double-crested Cormorants (Phalacrocorax auritus) from their nesting colonies have been documented to effect vegetation, soil chemistry and tree and plant health in the northern breeding grounds of Canada and the United States (U.S.). However, little work has been done on impacts to avian communities or in temperate forest ecosystems. We compared soil chemistry, vegetation and tree structure and diversity and effects on avian communities among colony islands, uninhabited islands and abandoned colony islands within Guntersville Reservoir, a temperate forest ecosystem. Concentrations of potassium (K), phosphorus (P) and nitrate (NO3-) in soil were negatively related to cormorant use, while tree diversity was lower on historic (tree mean = 4.35 ± 2.46 species) and colony (tree mean = 3.91 ± 3.12 species) islands relative to control islands (tree mean = 9.11 ± 3.88 species). Canopy cover was less (min: \u3c 20%), and midstories denser on colony and historic islands relative to control islands. Avian diversity was lower for colony islands (mean = 6 ± 3 species) than both control (11 ± 7 species) and historic (10 ± 7 species) islands. These effects of cormorant nesting can be seen even after 10 years of colony abandonment supporting that cormorants can have long-term effects on insular habitats even in temperate forest ecosystems

    Double-crested cormorant colony effects on soil chemistry, vegetation structure and avian diversity

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    Effects of Double-crested Cormorants (Phalacrocorax auritus) on vegetation, soil chemistry and tree health have been documented from their breeding colonies in the northern breeding grounds of Canada and the United States (U.S.) but not for areas within the southeastern United States where breeding activity is relatively novel. We compared vegetation and tree metrics such as structure diversity, and soil chemistry among colony islands, uninhabited islands, and abandoned colony islands within Guntersville Reservoir, a temperate forest ecosystem. Avian diversity and community structure were also quantified on these islands. Concentrations of potassium (K), phosphorus (P) and nitrate (NO3 −) in soil were negatively related to cormorant use, while tree diversity was lower on historic (tree mean=4.35 ± 2.46 species) and colony (tree mean=3.91 ± 3.12 species) islands relative to reference islands (tree mean=9.11 ± 3.88 species). Canopy cover was less (min:\u3c20%), and midstories denser on colony and historic islands relative to reference islands. Avian diversity was significantly lower for colony islands (mean=6 ± 3 species) than both reference (11 ± 7 species) and historic (10 ± 7 species) islands. These effects of cormorant nesting can be seen even after 10 years of colony abandonment supporting that cormorants can have long-term effects on insular habitats in temperate forest ecosystems

    Transcriptional Signatures of Tau and Amyloid Neuropathology

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    Alzheimer's disease (AD) is associated with the intracellular aggregation of hyperphosphorylated tau and the accumulation of β-amyloid in the neocortex. We use transgenic mice harboring human tau (rTg4510) and amyloid precursor protein (J20) mutations to investigate transcriptional changes associated with the progression of tau and amyloid pathology. rTg4510 mice are characterized by widespread transcriptional differences in the entorhinal cortex with changes paralleling neuropathological burden across multiple brain regions. Differentially expressed transcripts overlap with genes identified in genetic studies of familial and sporadic AD. Systems-level analyses identify discrete co-expression networks associated with the progressive accumulation of tau that are enriched for genes and pathways previously implicated in AD pathology and overlap with co-expression networks identified in human AD cortex. Our data provide further evidence for an immune-response component in the accumulation of tau and reveal molecular pathways associated with the progression of AD neuropathology.This article is freely available via Open Access. Click on the Publisher URL to access it via the publisher's site.WT_/Wellcome Trust/United Kingdom MR/M008924/1/MRC_/Medical Research Council/United Kingdompublished version, accepted version, submitted versio

    Carbon­yl[tris­(3,5-diphenyl­pyrazol-1-yl-κN 2)methane]copper(I) hexa­fluorido­phosphate–dichloro­methane–diethyl ether (4/3/1)

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    In the title compound, [Cu(C46H34N6)(CO)]PF6·0.75CH2Cl2·0.25C4H10O, the CuI atom is coordinated by three N atoms from the tridentate chelating tris­(3,5-diphenyl­pyrazol-1-yl)methane ligand (average Cu—N distance = 2.055 Å) and the C atom from a carbon monoxide ligand in a distorted tetra­hedral coordination geometry. The average N—Cu—N angle between adjacent pyrazole-ring-coordinated N atoms is 88.6°, while the average N—Cu—C angle between the pyrazole-bound N atom and the C atom of carbon monoxide is 126.3°. One of the 3-phenyl rings of the tris­(pyrazol­yl)methane ligand is disordered over two sites each with an occupancy factor of 0.50. The structure also exhibits disorder of the monosolvate that has been modeled with 0.75 CH2Cl2 and 0.25 Et2O occupancy

    A truncation allele in vascular endothelial growth factor c reveals distinct modes of signaling during lymphatic and vascular development

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    Vascular endothelial growth factor C (Vegfc) is a secreted protein that guides lymphatic development in vertebrate embryos. However, its role during developmental angiogenesis is not well characterized. Here, we identify a mutation in zebrafish vegfc that severely affects lymphatic development and leads to angiogenesis defects on sensitized genetic backgrounds. The um18 mutation prematurely truncated Vegfc, blocking its secretion and paracrine activity but not its ability to activate its receptor Flt4. When expressed in endothelial cells, vegfc(um18) could not rescue lymphatic defects in mutant embryos, but induced ectopic blood vessel branching. Furthermore, vegfc-deficient endothelial cells did not efficiently contribute to tip cell positions in developing sprouts. Computational modeling together with assessment of endothelial cell dynamics by time-lapse analysis suggested that an autocrine Vegfc/Flt4 loop plays an important role in migratory persistence and filopodia stability during sprouting. Our results suggest that Vegfc acts in two distinct modes during development: as a paracrine factor secreted from arteries to guide closely associated lymphatic vasculature and as an autocrine factor to drive migratory persistence during angiogenesis

    Soft novel form of white-etching matter and ductile failure of carbide-free bainitic steels under rolling contact stresses

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    There has been a great deal of work on the formation of hard white-etching regions in conventional bearing steels such as 1C-1.5Cr wt% when subjected repeatedly to rolling contact stresses. The regions are a consequence of localised mechanical attrition across microcrack faces and mixing, which refine the local structure and force cementite to dissolve. This white-etching matter is often associated with brittle phenomena because the hardness can exceed 1100 HV. In contrast, carbide-free mixtures of bainitic ferrite and retained austenite when subjected to the same loading have been unexpectedly found not to develop the characteristic patches of hard material and to show instead signs of ductility in the attrited regions. The work presented here shows that the white-etching areas that develop in carbide-free bainite are softer\textit{softer} than their surroundings, whether they are in hard nanostructured bainite destined for bearing applications or when the steel is designed for the manufacture of rails. Advanced characterisation tools were used for the first time to understand carbon redistribution during its formation. The deep interest about soft white-etching matter originates from the idea that it could lead to the reduction in premature failure of wind turbine gearbox bearings and white-etching layer grinding of rails.W. Solano-Alvarez appreciates and acknowledges funding by CONACYT, the Cambridge Overseas Trust, and the Roberto Rocca Education Programme. Part of this research was financed under EPSRC grant EP/M023303/1 “Designing steel composition and microstructure to better resist degradation during wheel-rail contact” in collaboration with the Rail Safety and Standards Board (RSSB), the Department of Transport, the University of Leeds, and Cranfield University for which we are thankful.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.actamat.2016.09.01

    An assessment of temporal, spatial and taxonomic trends in harmful algal toxin exposure in stranded marine mammals from the US New England coast

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    © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Fire, S. E., Bogomolni, A., DiGiovanni, R. A., Jr., Early, G., Leighfield, T. A., Matassa, K., Miller, G. A., Moore, K. M. T., Moore, M., Niemeyer, M., Pugliares, K., Wang, Z., & Wenzel, F. W. An assessment of temporal, spatial and taxonomic trends in harmful algal toxin exposure in stranded marine mammals from the US New England coast. Plos One, 16(1),(2021): e0243570, https://doi.org/10.1371/journal.pone.0243570.Despite a long-documented history of severe harmful algal blooms (HABs) in New England coastal waters, corresponding HAB-associated marine mammal mortality events in this region are far less frequent or severe relative to other regions where HABs are common. This long-term survey of the HAB toxins saxitoxin (STX) and domoic acid (DA) demonstrates significant and widespread exposure of these toxins in New England marine mammals, across multiple geographic, temporal and taxonomic groups. Overall, 19% of the 458 animals tested positive for one or more toxins, with 15% and 7% testing positive for STX and DA, respectively. 74% of the 23 different species analyzed demonstrated evidence of toxin exposure. STX was most prevalent in Maine coastal waters, most frequently detected in common dolphins (Delphinus delphis), and most often detected during July and October. DA was most prevalent in animals sampled in offshore locations and in bycaught animals, and most frequently detected in mysticetes, with humpback whales (Megaptera novaeangliae) testing positive at the highest rates. Feces and urine appeared to be the sample matrices most useful for determining the presence of toxins in an exposed animal, with feces samples having the highest concentrations of STX or DA. No relationship was found between the bloom season of toxin-producing phytoplankton and toxin detection rates, however STX was more likely to be present in July and October. No relationship between marine mammal dietary preference and frequency of toxin detection was observed. These findings are an important part of a framework for assessing future marine mammal morbidity and mortality events, as well as monitoring ecosystem health using marine mammals as sentinel organisms for predicting coastal ocean changes.S.F. - NOAA John H. Prescott Marine Mammal Rescue Assistance Grant Program #NA16NMF4390151 S.F. - NOAA John H. Prescott Marine Mammal Rescue Assistance Grant Program #NA17NMF4390082 S.F. - Florida Tech Department of Biological Sciences S.F. - Florida Tech John H. Evans Library Open Access Subvention Fund. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    Insights from the Inclusive Environments and Metrics in Biology Education and Research Network: Our Experience Organizing Inclusive Biology Education Research Events

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    In contrast to efforts focusing on improving inclusion in STEM classrooms from kindergarten through un-dergraduate (K–16), efforts to improve inclusion in scientific meetings and conferences, important hubs of STEM culture, are more recent. Markers of inclusion that are sometimes overlooked at these events can include the composition of panels, how workshops are run, the affordability of conferences, and various other mechanisms that maintain pre-existing hierarchies and norms that limit the participation of early-career researchers and individuals of minoritized cultural, linguistic, and economic backgrounds. The Inclusive Environments and Metrics in Biology Education and Research (iEMBER) network coordinates efforts of researchers from many fields interested in diversity and inclusion in biology education. Given the concerns regarding inclusion at professional meetings, iEMBER has developed and implemented several practices in planning and executing our meetings to make them more inclusive. In this report, we share our experiences developing inclusive meetings on biology education research and discuss the outcomes of such efforts. Spe-cifically, we present our approach to planning and executing the iEMBER 2019 conference and the National Association of Biology Teachers iEMBER 2019 workshop. This report adds to the growing body of resources on inclusive meetings, provides readers with an account of how such an attempt at implementation might unfold, and complements existing theories and work relating to the importance and functioning of such meetings in terms of representation in STEM

    The Time is Gone!? Pink Floyds "Time" (1973)

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    This paper provides a hermeneutic approach on Pink Floyds popular song "Time" from 1973s album Dark Side Of The Moon. The primary aim of this examination is the analysis of the conceptual connection of music and lyrics in this song. Moreover, derivation of semantic meaning potential is used to form an intersubjectively verifiable song interpretation. All in all, the main results of this analysis suggest a close connection of the songs musical parameters, i.e. form, harmony, melody, rhythm as well as sound, and its lyrical theme: (1) first the musique concrète in the songs introduction and the subsequent instrumental passage establish evident semantic relations to the following lyrical theme of fleeting time, (2) a devils circle of transitoriness of life is presented in the songs lyrics and is musically mirrored by periodic formal and harmonic repetitions, (3) the ambivalence of the bridges negative lyrics in combination with the sweet melodic thirds in the vocals suggests a melancholic atmosphere, (4) the lyrics description of a human life from birth to death is reflected in the formal structure and the harmony of »Time« as well as in the conceptual arrangement of Dark Side Of The Moons first LP-side from »Speak To Me« to »The Great Gig In The Sky«
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