2,461 research outputs found

    Induction of Colonic Aberrant Crypts in Mice by Feeding Apparent N-Nitroso Compounds Derived From Hot Dogs

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    Nitrite-preserved meats (e.g., hot dogs) may help cause colon cancer because they contain N-nitroso compounds. We tested whether purified hot-dog-derived total apparent N-nitroso compounds (ANC) could induce colonic aberrant crypts, which are putative precursors of colon cancer. We purified ANC precursors in hot dogs and nitrosated them to produce ANC. In preliminary tests, CF1 mice received 1 or 3 i.p. injections of 5mg azoxymethane (AOM)/kg. In Experiments 1 and 2, female A/J mice received ANC in diet. In Experiment 1, ANC dose initially dropped sharply because the ANC precursors had mostly decomposed but, later in Experiment 1 and throughout Experiment 2, ANC remained at 85 nmol/g diet. Mice were killed after 8 (AOM tests) or 17–34 (ANC tests) wk.Median numbers of aberrant crypts in the distal 2 cm of the colon for 1 and 3 AOMinjections, CF1 controls, ANC (Experiment 1), ANC (Experiment 2),and untreated A/J mice were 31, 74, 12, 20, 12, and 5–6, with P < 0.01 for both ANC tests. Experiment 2 showed somewhat increased numbers of colonic mucin-depleted foci in the ANC-treated group. We conclude that hot-dog-derived ANC induced significant numbers of aberrant crypts in the mouse colon

    Critical minerals and energy-impacts and limitations of moving to unconventional resources

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    © 2016 by the authors. The nexus of minerals and energy becomes ever more important as the economic growth and development of countries in the global South accelerates and the needs of new energy technologies expand, while at the same time various important minerals are declining in grade and available reserves from conventional mining. Unconventional resources in the form of deep ocean deposits and urban ores are being widely examined, although exploitation is still limited. This paper examines some of the implications of the transition towards cleaner energy futures in parallel with the shifts through conventional ore decline and the uptake of unconventional mineral resources. Three energy scenarios, each with three levels of uptake of renewable energy, are assessed for the potential of critical minerals to restrict growth under 12 alternative mineral supply patterns. Under steady material intensities per unit of capacity, the study indicates that selenium, indium and tellurium could be barriers in the expansion of thin-film photovoltaics, while neodymium and dysprosium may delay the propagation of wind power. For fuel cells, no restrictions are observed

    Lithium dihydropyridine dehydrogenation catalysis : a group 1 approach to cyclisation of diamine-boranes

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    In reactions restricted previously to a ruthenium catalyst, a 1-lithium-2-alkyl-1,2-dihydropyridine complex is shown to be a competitive alternative dehydrogenation catalyst for the transformation of diamine boranes to cyclic 1,3,2-diazaborolidines, which can in turn be smoothly arylated in good yields. This study establishes the conditions and solvent dependence of the catalysis via NMR monitoring, with mechanistic insight provided by NMR (including DOSY) experiments and X-ray crystallographic studies of several model lithio intermediates

    Fecal glucocorticoids and anthropogenic injury and mortality in North Atlantic right whales Eubalaena glacialis

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    © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Endangered Species Research 34 (2017): 417-429, doi:10.3354/esr00866.As human impacts on marine ecosystems escalate, there is increasing interest in quantifying sub-lethal physiological and pathological responses of marine mammals. Glucocorticoid hormones are commonly used to assess stress responses to anthropogenic factors in wildlife. While obtaining blood samples to measure circulating hormones is not currently feasible for free-swimming large whales, immunoassay of fecal glucocorticoid metabolites (fGCs) has been validated for North Atlantic right whales Eubalaena glacialis (NARW). Using a general linear model, we compared fGC concentrations in right whales chronically entangled in fishing gear (n = 6) or live-stranded (n = 1), with right whales quickly killed by vessels (n = 5) and healthy right whales (n = 113) to characterize fGC responses to acute vs. chronic stressors. fGCs in entangled whales (mean ± SE: 1856.4 ± 1644.9 ng g-1) and the stranded whale (5740.7 ng g-1) were significantly higher than in whales killed by vessels (46.2 ± 19.2 ng g-1) and healthy whales (51.7 ± 8.7 ng g-1). Paired feces and serum collected from the live-stranded right whale provided comparison of fGCs in 2 matrices in a chronically stressed whale. Serum cortisol and corticosterone in this whale (50.0 and 29.0 ng ml-1, respectively) were much higher than values reported in other cetaceans, in concordance with extremely elevated fGCs. Meaningful patterns in fGC concentration related to acute vs. chronic impacts persisted despite potential for bacterial degradation of hormone metabolites in dead whales. These results provide biological validation for using fGCs as a biomarker of chronic stress in NARWs.This research was funded by the NOAA/NMFS, Office of Naval Research Marine Mammals and Biology Program, Northeast Consortium, Island Foundation, Irving Oil, NEAq Internal Research Fund, Prescott Grant NA08NMF4390590, and NOAA CINAR Cooperative Agreement NA09OAR4320129

    ‘It’s where I belong’: what does it mean to age in place from the perspective of people aged 80 and above? A longitudinal qualitative study (wave one)

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    \ua9 The Author(s) 2024.Background: Most people want to remain at home as they age. Ageing in place – remaining at home and connected to the community – is a national and international policy priority; however, to better understand how policy might be implemented, a more nuanced understanding is required about older adults’ lived experiences of ageing in place, especially the experiences of those aged 80 and above. Objective: To describe and explore the social processes which enable ageing in place from the perspective of community-dwelling older people (80+). Methods: Forty-six respondents (80–100+ years) participated in the first wave of a longitudinal qualitative study set in North East England. Semi-structured interviews were conducted in participants’ homes between June 2022 and January 2023. Interviews were analysed using reflexive thematic analysis. Results: Participants positioned their homes as a place of freedom and as the antithesis of a ‘care home’. Remaining in place was important for all participants; a key priority for them was to remain physically active to enable this. However, many participants faced significant hurdles to remaining in place. These were primarily related to health and mobility issues. Some participants were able to overcome such barriers by drawing on financial resources and available social networks. Conclusion: The home is central to understanding older peoples’ (80+) experiences of ageing. In a socio-political context which promotes ageing in place, the social factors shaping experiences of ageing in place must be considered. This involves attending to the challenges of later life, particularly health and especially mobility and physical function. Currently, those with resources (social and economic) are better equipped to respond to such challenges, thus potentially exacerbating widening inequalities in ageing. By foregrounding the perspectives of those ageing in place alongside social factors shaping their experiences, our study has important implications for policy and health and social care. We show that a more equitable allocation of resources is vital to fulfil the ageing in place policy agenda. Furthermore, we highlight a need to recognise commitments to ageing in place displayed by people aged 80 and above, especially when remaining in place becomes difficult to achieve

    A study to define meteorological uses and performance requirements for the Synchronous Earth Observatory Satellite

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    The potential meteorological uses of the Synchronous Earth Observatory Satellite (SEOS) were studied for detecting and predicting hazards to life, property, or the quality of the environment. Mesoscale meteorological phenonmena, and the observations requirements for SEOS are discussed along with the sensor parameters

    Accessible heavier s-block dihydropyridines : structural elucidation and reactivity of isolable molecular hydride sources

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    The straightforward metathesis of 1-lithio-2-tbutyl-1,2-dihydropyridine using metal tert-butoxide (Na/K) has resulted in the first preparation and isolation of a series of heavier alkali metal dihydropyridines. By employing donors, TMEDA, PMDETA and THF, five new metallodihydropyridine compounds were isolated and fully characterised. Three distinct structural motifs have been observed; a dimer, a dimer of dimers and a novel polymeric dihydropyridylpotassium compound, and the influence of cation π-interactions therein has been discussed. Thermal volatility analysis has shown that these complexes have the potential to be used as simple isolable sodium or potassium hydride surrogates, which is confirmed in test reactions with benzophenone

    Agricultural Conservation Planning Framework: 1. Developing Multipractice Watershed Planning Scenarios and Assessing Nutrient Reduction Potential

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    Spatial data on soils, land use, and topography, combined with knowledge of conservation effectiveness, can be used to identify alternatives to reduce nutrient discharge from small (hydrologic unit code [HUC]12) watersheds. Databases comprising soil attributes, agricultural land use, and light detection and ranging–derived elevation models were developed for two glaciated midwestern HUC12 watersheds: Iowa’s Beaver Creek watershed has an older dissected landscape, and Lime Creek in Illinois is young and less dissected. Subsurface drainage is common in both watersheds. We identified locations for conservation practices, including in-field practices (grassed waterways), edge-of-field practices (nutrient-removal wetlands, saturated buffers), and drainage-water management, by applying terrain analyses, geographic criteria, and cross-classifications to field- and watershed-scale geographic data. Cover crops were randomly distributed to fields without geographic prioritization. A set of alternative planning scenarios was developed to represent a variety of extents of implementation among these practices. The scenarios were assessed for nutrient reduction potential using a spreadsheet approach to calculate the average nutrient-removal efficiency required among the practices included in each scenario to achieve a 40% NO3–N reduction. Results were evaluated in the context of the Iowa Nutrient Reduction Strategy, which reviewed nutrient-removal efficiencies of practices and established the 40% NO3–N reduction as Iowa’s target for Gulf of Mexico hypoxia mitigation by agriculture. In both test watersheds, planning scenarios that could potentially achieve the targeted NO3–N reduction but remov
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