761 research outputs found

    Vapor pressures of acetylene at low temperatures

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    The atmospheres of many of the outer planets and their satellites contain a large number of hydrocarbon species. In particular, acetylene (C2H2) has been identified at Jupiter, Saturn and its satellite Titan, Uranus and Neptune. In the lower atmospheres of these planets, where colder temperatures prevail, the condensation and/or freezing of acetylene is probable. In order to obtain accurate models of the acetylene in these atmospheres, it is necessary to have a complete understanding of its vapor pressures at low temperatures. Vapor pressures at low temperatures for acetylene are being determined. The vapor pressures are measured with two different techniques in order to cover a wide range of temperatures and pressures. In the first, the acetylene is placed in a sample tube which is immersed in a low temperature solvent/liquid nitrogen slush bath whose temperature is measured with a thermocouple. The vapor pressure is then measured directly with a capacitance manometer. For lower pressures, a second technique which was called the thin-film infrared method (TFIR) was developed. It involves measuring the disappearance rate of a thin film of acetylene at a particular temperature. The spectra are then analyzed using previously determined extinction coefficient values, to determine the disappearance rate R (where R = delta n/delta t, the number of molecules that disappear per unit time). This can be related to the vapor pressure directly. This technique facilitates measurement of the lower temperatures and pressures. Both techniques have been calibrated using CO2, and have shown good agreement with the existing literature data

    Bridging groundwater models and decision support with a Bayesian network

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    Author Posting. © American Geophysical Union, 2013. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Water Resources Research 49 (2013): 6459–6473, doi:10.1002/wrcr.20496.Resource managers need to make decisions to plan for future environmental conditions, particularly sea level rise, in the face of substantial uncertainty. Many interacting processes factor in to the decisions they face. Advances in process models and the quantification of uncertainty have made models a valuable tool for this purpose. Long-simulation runtimes and, often, numerical instability make linking process models impractical in many cases. A method for emulating the important connections between model input and forecasts, while propagating uncertainty, has the potential to provide a bridge between complicated numerical process models and the efficiency and stability needed for decision making. We explore this using a Bayesian network (BN) to emulate a groundwater flow model. We expand on previous approaches to validating a BN by calculating forecasting skill using cross validation of a groundwater model of Assateague Island in Virginia and Maryland, USA. This BN emulation was shown to capture the important groundwater-flow characteristics and uncertainty of the groundwater system because of its connection to island morphology and sea level. Forecast power metrics associated with the validation of multiple alternative BN designs guided the selection of an optimal level of BN complexity. Assateague island is an ideal test case for exploring a forecasting tool based on current conditions because the unique hydrogeomorphological variability of the island includes a range of settings indicative of past, current, and future conditions. The resulting BN is a valuable tool for exploring the response of groundwater conditions to sea level rise in decision support.This work was funded by the USGS Climate and Land Use Mission Area, Research and Development Program and the USGS Natural Hazards Mission Area, Coastal and Marine Geology Program

    Effects of sea-level rise on barrier island groundwater system dynamics – ecohydrological implications

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    This paper is not subject to U.S. copyright. The definitive version was published in Ecohydrology 7 (2014): 1064–1071, doi:10.1002/eco.1442.We used a numerical model to investigate how a barrier island groundwater system responds to increases of up to 60 cm in sea level. We found that a sea-level rise of 20 cm leads to substantial changes in the depth of the water table and the extent and depth of saltwater intrusion, which are key determinants in the establishment, distribution and succession of vegetation assemblages and habitat suitability in barrier islands ecosystems. In our simulations, increases in water-table height in areas with a shallow depth to water (or thin vadose zone) resulted in extensive groundwater inundation of land surface and a thinning of the underlying freshwater lens. We demonstrated the interdependence of the groundwater response to island morphology by evaluating changes at three sites. This interdependence can have a profound effect on ecosystem composition in these fragile coastal landscapes under long-term changing climatic conditions.We used a numerical model to investigate how a barrier island groundwater system responds to increases of up to 60 cm in sea level. We found that a sea-level rise of 20 cm leads to substantial changes in the depth of the water table and the extent and depth of saltwater intrusion, which are key determinants in the establishment, distribution and succession of vegetation assemblages and habitat suitability in barrier islands ecosystems. In our simulations, increases in water-table height in areas with a shallow depth to water (or thin vadose zone) resulted in extensive groundwater inundation of land surface and a thinning of the underlying freshwater lens. We demonstrated the interdependence of the groundwater response to island morphology by evaluating changes at three sites. This interdependence can have a profound effect on ecosystem composition in these fragile coastal landscapes under long-term changing climatic conditions. Published 2013. This article is a U.S. Government work and is in the public domain in the USA

    Nebulized mesenchymal stem cell derived conditioned medium ameliorates Escherichia coli induced pneumonia in a rat model

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    BackgroundMesenchymal stem cells (MSC) have shown immense therapeutic promise in a range of inflammatory diseases, including acute respiratory distress syndrome (ARDS), and are rapidly advancing through clinical trials. Among their multimodal mechanisms of action, MSCs exert strong immunomodulatory effects via their secretome, which contains cytokines, small molecules, extracellular vesicles, and a range of other factors. Recent studies have shown that the MSC secretome can recapitulate many of the beneficial effects of the MSC itself. We aimed to determine the therapeutic capacity of the MSC secretome in a rat bacterial pneumonia model, especially when delivered directly to the lung by nebulization which is a technique more appropriate for the ventilated patient.MethodsConditioned medium (CM) was generated from human bone marrow derived MSCs in the absence of antibiotics and serum supplements. Post-nebulization lung penetration was estimated through nebulization of CM to a cascade impactor and simulated lung and quantification of collected total protein and IL-8 cytokine. Control and nebulized CM was added to a variety of lung cell culture models and injury resolution assessed. In a rat E. coli pneumonia model, CM was instilled or administered by nebulization and lung injury and inflammation assessed at 48 h.ResultsMSC-CM was predicted to have good distal lung penetration and delivery when administered by nebulizer. Both control and nebulized CM reduced NF-κB activation and inflammatory cytokine production in lung cell culture, while promoting cell viability and would closure in oxidative stress and scratch wound models. In a rat bacterial pneumonia model, both instilled and nebulizer delivered CM improved lung function, increasing blood oxygenation and reducing carbon dioxide levels compared to unconditioned medium controls. A reduction in bacterial load was also observed in both treatment groups. Inflammatory cytokines were reduced significantly by both liquid and aerosol CM administration, with less IL-1β, IL-6, and CINC1 in these groups compared to controls.ConclusionMSC-CM is a potential therapeutic for pneumonia ARDS, and administration is compatible with vibrating mesh nebulization

    A new multiplex SARS-CoV-2 antigen microarray showed correlation of IgG, IgA, and IgM antibodies from patients with COVID-19 disease severity and maintenance of relative IgA and IgM antigen binding over time

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    Zoonotic spillover of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to humans in December 2019 caused the coronavirus disease 2019 (COVID-19) pandemic. Serological monitoring is critical for detailed understanding of individual immune responses to infection and protection to guide clinical therapeutic and vaccine strategies. We developed a high throughput multiplexed SARS-CoV-2 antigen microarray incorporating spike (S) and nucleocapsid protein (NP) and fragments expressed in various hosts which allowed simultaneous assessment of serum IgG, IgA, and IgM responses. Antigen glycosylation influenced antibody binding, with S glycosylation generally increasing and NP glycosylation decreasing binding. Purified antibody isotypes demonstrated a binding pattern and intensity different from the same isotype in whole serum, probably due to competition from the other isotypes present. Using purified antibody isotypes from naĂŻve Irish COVID-19 patients, we correlated antibody isotype binding to different panels of antigens with disease severity, with binding to the S region S1 expressed in insect cells (S1 Sf21) significant for IgG, IgA, and IgM. Assessing longitudinal response for constant concentrations of purified antibody isotypes for a patient subset demonstrated that the relative proportion of antigen-specific IgGs decreased over time for severe disease, but the relative proportion of antigen-specific IgA binding remained at the same magnitude at 5 and 9 months post-first symptom onset. Further, the relative proportion of IgM binding decreased for S antigens but remained the same for NP antigens. This may support antigen-specific serum IgA and IgM playing a role in maintaining longer-term protection, important for developing and assessing vaccine strategies. Overall, these data demonstrate the multiplexed platform as a sensitive and useful platform for expanded humoral immunity studies, allowing detailed elucidation of antibody isotypes response against multiple antigens. This approach will be useful for monoclonal antibody therapeutic studies and screening of donor polyclonal antibodies for patient infusions

    Improved diagnosis of SARS-CoV-2 by using nucleoprotein and spike protein fragment 2 in quantitative dual ELISA tests

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    The novel coronavirus, severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), is the causative agent of the 2020 worldwide coronavirus pandemic. Antibody testing is useful for diagnosing historic infections of a disease in a population. These tests are also a helpful epidemiological tool for predicting how the virus spreads in a community, relating antibody levels to immunity and for assessing herd immunity. In the present study, SARS-CoV-2 viral proteins were recombinantly produced and used to analyse serum from individuals previously exposed, or not, to SARS-CoV-2. The nucleocapsid (Npro) and spike subunit 2 (S2Frag) proteins were identified as highly immunogenic, although responses to the former were generally greater. These two proteins were used to develop two quantitative enzyme-linked immunosorbent assays (ELISAs) that when used in combination resulted in a highly reliable diagnostic test. Npro and S2Frag-ELISAs could detect at least 10% more true positive coronavirus disease-2019 (COVID-19) cases than the commercially available ARCHITECT test (Abbott). Moreover, our quantitative ELISAs also show that specific antibodies to SARS-CoV-2 proteins tend to wane rapidly even in patients who had developed severe disease. As antibody tests complement COVID-19 diagnosis and determine population-level surveillance during this pandemic, the alternative diagnostic we present in this study could play a role in controlling the spread of the virus

    “There was something very peculiar about Doc…”: Deciphering Queer Intimacy in Representations of Doc Holliday

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    This is an Accepted Manuscript of an article published by Taylor & Francis in American Nineteenth-Century History on 8-12-14, available online: http://dx.doi.org/10.1080/14664658.2014.971481This essay discusses representations of male intimacy in life-writing about consumptive gunfighter John Henry “Doc” Holliday (1851-1887). I argue that twentieth-century commentators rarely appreciated the historical specificity of Holliday’s friendships in a frontier culture that not only normalized but actively celebrated same-sex intimacy. Indeed, Holliday lived on the frayed edges of known nineteenth-century socio-sexual norms, and his interactions with other men were further complicated by his vicious reputation and his disability. His short life and eventful afterlife exposes the gaps in available evidence – and the flaws in our ability to interpret it. Yet something may still be gleaned from the early newspaper accounts of Holliday. Having argued that there is insufficient evidence to justify positioning him within modern categories of hetero/homosexuality, I analyze the language used in pre-1900 descriptions of first-hand encounters with Holliday to illuminate the consumptive gunfighter’s experience of intimacy, if not its meaning

    Nolanville Comprehensive Plan 2015-2030

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    Comprehensive plans are “the central organizing umbrella under which other plans, regulations, and initiatives exist.” They typically have long-range planning horizons between 20 and 30 years. These public documents, along with relevant zoning maps, can be used to guide, support, and justify city land use and decision-making in the future. A comprehensive plan should include the overall vision for the community, as well as a plan for the physical growth, development, and preservation of the land. Furthermore, an inclusive comprehensive plan should envision future growth in the various fields of transportation, community facilities and infrastructure, economy, parks and open spaces, natural and cultural resources, and housing.In the fall 2014, the City of Nolanville and Texas Target Communities partnered to create a planning task force to represent the community. The task force was integral to the planning process, contributing the thoughts, desires, and opinions of community members—as well as their enthusiasm about Nolanville’s future. This fourteen-month planning process ended in September 2015. All the material included in the plan is the result of work accomplished in four different graduate level classes spanning two semesters at Texas A&M University as part of the Master of Urban Planning program.The result of this collaboration is the City of Nolanville Comprehensive Plan 2015 - 2030, which is the official policy guide for the community’s growth over the next twenty years.Texas Target Communitie
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