282 research outputs found

    Early Miocene Cape Blanco Flora of Oregon

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    Deposition of the shallow marine sandstone of Floras Lake was interrupted by a transient deltaic progradation of redeposited volcanic tuff, which contains the Cape Blanco flora.  Dating by 40Ar/39Ar on fresh plagioclase constrains the age of the plant-bearing tuff to 18.24 ± 0.86 Ma, because we interpret this age of eruption and landscape loading with ash, as within only a few years of redeposition.  Several plausible sources of the tuff can be identified from caldera eruptions in the Cascade Volcanic Arc.  The relation between the early Miocene Cascade volcanic arc and the Klamath Terrane has been fixed since the early Miocene, and the high Cr2O3 in the sandstones is an indication that the source area for the sandstone of Floras Lake was the Klamath Terrane.  Fossil leaves and other plant organs of 33 species of the Cape Blanco flora represent floral diversity and paleoclimate of coastal Oregon during the early Miocene. The flora includes a variety of thermophilic elements from California, including coast redwood (Sequoia affinis), and avocado (Persea pseudocarolinensis), and is numerically dominated by live oak (Quercus hannibalii), and chinquapin (Chrysolepis sonomensis). The size and proportion of serrate margins of the fossil leaves are evidence of mean annual temperature of ~14 º C and a mean annual precipitation of ~223 cm/yr for the Cape Blanco flora.  Comparison of the Cape Blanco flora with the Temblor flora of California and the Seldovia flora of Alaska reveals a latitudinal gradient of ~ 0.6 º C/degree latitude, compared with a gradient of ~0.3 º C/degree latitude from isotopic composition of marine foraminifera of the northeast Pacific Ocean.  Both results confirm that the late early Miocene mean annual temperature at 45º north latitude was 4-5 º C warmer than today

    Targeting hydrogen sulfide breakdown for regulation of myocardial injury and repair

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    Hydrogen sulfide (H2S) is an endogenous gasotransmitter that regulates vascular function and blood pressure, and also protects the heart from injury associated with myocardial infarction (MI). The mitochondrial enzyme thiosulfate sulfurtransferase (TST) has a putative role in the breakdown of H2S but its role in the cardiovascular system is unknown. I hypothesised that TST reduces cardiovascular H2S availability and that inhibiting TST activity may therefore ameliorate cardiovascular pathology. In the heart, TST was expressed by cardiomyocytes and vascular smooth muscle cells. Tst-/- mice all survived to adulthood and had normal cardiac structure and function. Cardiac and hepatic H2S breakdown rates were reduced and H2S levels were higher in the blood of Tst-/- mice. However, in heart tissue, protein levels for the H2S-activated Nrf2 downstream targets, thioredoxin (Trx1) and heme oxygenase-1 (HO-1) were comparable. In contrast, protein levels for the cardiac specific H2S-synthetic enzyme, cystathionine gamma lyase (CSE) was reduced, suggesting a homeostatic negative feedback mechanism to maintain H2S at non-toxic levels. Respiration, measured using an oxygen-sensing electrode was normal in isolated mitochondria from whole Tst-/- compared to control C57BL6 hearts. Endothelial nitric oxide synthase (eNOS) protein expression was lower in Tst-/- hearts, highlighting potential cross talk between H2S and nitric oxide (NO) signalling. TST was expressed in whole aorta homogenates and in isolated endothelial cells from aorta and small intramuscular vessels of the hindlimb from C57BL/6N control mice. Myography and western blotting revealed a greater influence of NO in aorta from Tst-/- mice that was associated with increased phosphorylation of the activating serine1177 residue of eNOS (PeNOSSer1177). NO plays a lesser role in resistance arteries, but in comparison to control vessels, small mesenteric vessels from Tst-/- mice was more reliant on small and intermediate calcium activated potassium channels for relaxation. Tst-/- mice were normotensive, despite this alteration in the regulation of vascular tone. However, metabolic cage experiments identified that Tst-/- mice presented with diuresis, polydipsia, and increased urinary electrolyte excretion of sodium, potassium and chloride, possibly to compensate for increased vascular tone in order to maintain stable blood pressure. To investigate the role of TST in regulating the response to pathological challenge, MI was induced by coronary artery ligation (CAL). In control mice, gene expression of CSE was downregulated by 2 days after CAL, but TST expression was 12-fold increased, suggesting regulation of H2S bioavailability during the acute MI-healing phase. Tst-/- male mice had a 40% greater incidence of cardiac rupture during infarct healing and surviving Tst-/- mice had greater left ventricular dilatation and impaired function compared to controls. Ex vivo, isolated perfused hearts from Tst-/- mice were more susceptible to ischaemia/ reperfusion injury, suggesting an additional role of TST in determining cardiomyocyte susceptibility to injury. In conclusion, these data indicate that cardiovascular H2S bioavailability is regulated through degradation by TST. The data presented here provide evidence for significant tissue specific crosstalk between H2S synthetic and degradative mechanisms and between H2S and other local regulatory mechanisms, including ion channels and NOS. We infer TST has a physiological role in the kidney where its loss leads to changes in renal electrolyte and water handling, although other compensatory mechanisms prevent a change in blood pressure. Under conditions of pathological challenge following MI, loss of TST is detrimental, illustrating its key role in removal of H2S. The data refute the original hypothesis that TST inhibition would be protective against cardiovascular pathology. Further studies in mice with tissue specific deletion of TST are now required to more fully reveal the cardiovascular role of TST

    Book Reviews

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    Reviews of the following books: Acadia, Maine, and New Scotland: Marginal Colonies in the Seventeenth Century by John G. Reid; Faces of Maine by Bob Niss; Morning Was Starlight: My Maine Boyhood by Ernest Dodge

    Concord Companions: Margaret Fuller, Friendship, and Desire

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    In this paper, we examine the rhetoric of friendship and desire in mid-nineteenth-century American writing. We begin by looking at Emerson's essay on friendship and Thoreau's poem "Sympathy" (1840) to provide a context for reading Margaret Fuller's fascinating texts on samesex bonds between women. Of particular interest to us is Fuller's translation of Elizabeth von Arnim's Die Gunderode (1840), a collection of letters between Arnim and the German Romantic poet Karoline von Gunderode which provides compelling insights into the early to mid-nineteenth-century continuum between female friendship and same-sex desire. We situate this translation alongside Fuller's own female friendships and expressions of love for women, more specifically her declarations of love to Anna Barker and, later, to George Sand. This latter relationship, we suggest, was a source of admiration and anxiety, for Sand's cross-dressing and fluid sense of gender identity was simultaneously celebrated and condemned in Fuller's Women in the Nineteenth Century (1843)

    Modeled Chl:C ratio and derived estimates of phytoplankton carbon biomass and its contribution to total particulate organic carbon in the global surface ocean

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    Chlorophyll (Chl) is a distinctive component of autotrophic organisms, often used as an indicator of phytoplankton biomass in the ocean. However, assessment of phytoplankton biomass from Chl relies on the accurate estimation of the Chl:carbon(C) ratio. Here we present global patterns of Chl:C ratios in the surface ocean obtained from a phytoplankton growth model that accounts for the optimal acclimation of phytoplankton to ambient nutrient, light, and temperature conditions. The model agrees largely with observed/expected global patterns of Chl:C. Combining our Chl:C estimates with satellite Chl and particulate organic carbon (POC), we infer phytoplankton C concentration in the surface ocean and its contribution to the total POC pool. Our results suggest that the portion of POC corresponding to living phytoplankton is higher in subtropical latitudes and less productive regions (∼30–70%) and decreases to ∼10–30% toward high latitudes and productive regions. An important caveat of our model is the lack of iron limiting effects on phytoplankton physiology. Comparison of our predicted phytoplankton biomass with an independent estimate of total POC reveals a positive correlation between nitrate concentrations and nonphotosynthetic POC in the surface ocean. This correlation disappears when a constant Chl:C is applied. Our analysis is not constrained by assumptions of constant Chl:C or phytoplankton:POC ratio, providing a novel independent analysis of phytoplankton biomass in the surface ocean. These results highlight the importance of accounting for the variability in Chl:C and its application in distinguishing the autotrophic and heterotrophic components in the assemblage of the marine plankton ecosystem

    The Hepatic Compensatory Response to Elevated Systemic Sulfide Promotes Diabetes

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    Impaired hepatic glucose and lipid metabolism are hallmarks of type 2 diabetes. Increased sulfide production or sulfide donor compounds may beneficially regulate hepatic metabolism. Disposal of sulfide through the sulfide oxidation pathway (SOP) is critical for maintaining sulfide within a safe physiological range. We show that mice lacking the liver- enriched mitochondrial SOP enzyme thiosulfate sulfurtransferase (Tst−/− mice) exhibit high circulating sulfide, increased gluconeogenesis, hypertriglyceridemia, and fatty liver. Unexpectedly, hepatic sulfide levels are normal in Tst−/− mice because of exaggerated induction of sulfide disposal, with associated suppression of global protein persulfidation and nuclear respiratory factor 2 target protein levels. Hepatic proteomic and persulfidomic profiles converge on gluconeogenesis and lipid metabolism, revealing a selective deficit in medium-chain fatty acid oxidation in Tst−/− mice. We reveal a critical role of TST in hepatic metabolism that has implications for sulfide donor strategies in the context of metabolic disease

    The role of grassland sward islets in the distribution of arthropods in cattle pastures

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    1. It is well documented that cattle reduce their grazing activity in the vicinity of cattle dung, which gives rise to distinct patches, or islets as they have been termed, of longer sward. The influence of such islets on pasture utilisation and agronomic performance has been widely studied, but very little information is available concerning their influence on grassland biodiversity. 2. In this study the abundance and distribution of arthropods in relation to islets was assessed, using suction sampling, at 26 commercial farms and in a replicated pasture management experiment in the south and east of Ireland. 3. Islets were found to cover approximately 24% of pastures and to contain between 40% and 50% of arthropod individuals. 4. Islets consistently contained a higher density of arthropods, even when the difference in mean sward height between islets and more strongly grazed sward was accounted for. The relative concentration of arthropods in islets declined with increasing mean sward height, which may be related to the recovery of well-grazed non-islet sward. Islets appear to act as refugia from sward removal. 5. The potential importance of islets in maintaining arthropod biodiversity within intensively grazed pastures and the wider grass-based farming landscape is discussed, particularly with reference to standard agronomic practices such as sward topping and chain harrowing, which aim to remove the sward heterogeneity created by grazing livestock

    Allogeneic Mesenchymal Cell Therapy in Anthracycline-Induced Cardiomyopathy Heart Failure Patients: The CCTRN SENECA Trial.

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    BACKGROUND: Anthracycline-induced cardiomyopathy (AIC) may be irreversible with a poor prognosis, disproportionately affecting women and young adults. Administration of allogeneic bone marrow-derived mesenchymal stromal cells (allo-MSCs) is a promising approach to heart failure (HF) treatment. OBJECTIVES: SENECA (Stem Cell Injection in Cancer Survivors) was a phase 1 study of allo-MSCs in AIC. METHODS: Cancer survivors with chronic AIC (mean age 56.6 years; 68% women; NT-proBNP 1,426 pg/ml; 6 enrolled in an open-label, lead-in phase and 31 subjects randomized 1:1) received 1 × 10 RESULTS: A total of 97% of subjects underwent successful study product injections; all allo-MSC-assigned subjects received the target dose of cells. Follow-up visits were well-attended (92%) with successful collection of endpoints in 94% at the 1-year visit. Although 58% of subjects had non-CMR compatible devices, CMR endpoints were successfully collected in 84% of subjects imaged at 1 year. No new tumors were reported. There were no significant differences between allo-MSC and vehicle groups with regard to clinical outcomes. Secondary measures included 6-min walk test (p = 0.056) and Minnesota Living with Heart Failure Questionnaire score (p = 0.048), which tended to favor the allo-MSC group. CONCLUSIONS: In this first-in-human study of cell therapy in patients with AIC, transendocardial administration of allo-MSCs appears safe and feasible, and CMR was successfully performed in the majority of the HF patients with devices. This study lays the groundwork for phase 2 trials aimed at assessing efficacy of cell therapy in patients with AIC

    Innovative methods of community engagement: towards a low carbon climate resilient future

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    The proceedings of the Innovative Methods of Community Engagement: Toward a Low Carbon, Climate Resilient Future workshop have been developed by the Imagining2050 team in UCC and the Secretariat to the National Dialogue on Climate Action (NDCA). The NDCA also funded the workshop running costs. The proceedings offer a set of recommendations and insights into leveraging different community engagement approaches and methodologies in the area of climate action. They draw from interdisciplinary knowledge and experiences of researchers for identifying, mobilizing and mediating communities. The work presented below derives from a workshop held in the Environmental Research Institute in UCC on the 17th January 2019. These proceedings are complementary to an earlier workshop also funded by the NDCA and run by MaREI in UCC, titled ‘How do we Engage Communities in Climate Action? – Practical Learnings from the Coal Face’. The earlier workshop looked more closely at community development groups and other non-statutory organizations doing work in the area of climate change
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