1,057 research outputs found

    Interferometric imaging of the high-redshift radio galaxy, 4C60.07: An SMA, Spitzer and VLA study reveals a binary AGN/starburst

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    ‘The definitive version is available at www3.interscience.wiley.com '. Copyright Blackwell / RAS. DOI: 10.1111/j.1365-2966.2008.13811.xPeer reviewe

    Flow cell coupled dynamic light scattering for real-time monitoring of nanoparticle size during liquid phase bottom-up synthesis

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    To tailor the properties of nanoparticles and nanocomposites, precise control over particle size is of vital importance. Real-time monitoring of particle size during bottom-up synthesis in liquids would allow a detailed study of particle nucleation and growth, which provides valuable insights in the mechanism of formation of the nanoparticles. Furthermore, it facilitates a rational scale-up, and would enable adequate intervention in the production process of nanoparticle dispersions to minimize the number of off-spec batches. Since real-time monitoring requires particle size measurements on dispersions in flow, conventional dynamic light scattering (DLS) techniques are not suited: they rely on single scattering and measure the Brownian motion of particles dispersed in a liquid. Here, we present a set-up that allows accurate measurements in real-time on flowing dispersions using a DLS technique based on modulated 3D cross-correlation. This technique uses two simultaneous light scattering experiments performed at the same scattering vector on the same sample volume in order to extract only the single scattering information common to both. We connected the reactor to a flow-cell in the DLS equipment using a tailor-made analysis loop, and successfully demonstrated the complete set-up through monitoring of the size of spherical silica nanoparticles during Stöber synthesis in a water-alcohol mixture starting from the molecular precursor tetraethyl orthosilicate.</p

    Unusual morphologies and the occurrence of pseudomorphs after ikaite (CaCO3•6H2O) in fast growing, hyperalkaline speleothem

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    Unusual speleothem, associated with hyperalkaline (pH>12) groundwaters have formed within a shallow, abandoned railway tunnel at Peak Dale, Derbyshire, UK. The hyperalkaline groundwaters are produced by the leaching of a thin layer (<2 m) of old lime kiln waste above the soil-bedrock surface above the tunnel by rainwater. This results in a different reaction and chemical process to that more commonly associated with the formation of calcium carbonate speleothems from Ca-HCO3-type groundwaters and degassing of CO2. Stalagmites within the Peak Dale tunnel have grown rapidly (averaging 33 mm y-1), following the closure of the tunnel 70 years ago. They have an unusual morphology comprising a central sub-horizontally-laminated column of micro- to nano-crystalline calcium carbonate encompassed by an outer sub-vertical assymetric ripple laminated layer. The stalagmites are largely composed of secondary calcite forming pseudomorphs (<1 mm) which we believe to be predominantly after the ‘cold climate’ calcium carbonate polymorph, ikaite (calcium carbonate hexahydrate: CaCO3•6H2O), with minor volumes of small (<5 μm) pseudomorphs after vaterite. The tunnel has a near constant temperature of 8-9°C which is slightly above the previously published crystallisation temperatures for ikaite (<6°C). Analysis of a stalagmite actively growing at the time of sampling, and preserved immediately within a dry nitrogen cryogenic vessel, indicates that following crystallisation of ikaite, decomposition to calcite occurs rapidly, if not instantaneously. We believe this is the first occurrence of this calcium carbonate polymorph observed within speleothem

    Engaging Long-Term Care Workers in Research: Recruitment Approaches and Participant Characteristics From a Randomized Controlled Trial to Improve COVID-19 Vaccine Confidence.

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    To describe and compare the recruitment methods employed in a randomized controlled trial targeting long-term care workers, and resulting participant baseline characteristics. We used a multifaceted recruitment process to enroll long-term care workers in our 3-arm randomized controlled trial comparing 2 interventions to enhanced usual practice, for improving COVID-19 vaccine confidence and other outcomes. Adult long-term care workers living in the United States employed within the last 2 years were invited to join the study. Participants also had to meet specific screening criteria related to their degree of worry about the vaccine and/or their vaccination status. We used a participatory approach to engage our long-term care stakeholders in codesigning and executing a combination of recruitment methods, including targeted e-recruitment, paid e-recruitment, and in-person recruitment. Participants were screened, consented, and enrolled online. We implemented a participant verification process to ensure the integrity of our study data, and used a tailored participant management platform to manage enrollment. We enrolled 1930 long-term care workers between May 2022 and January 2023. We met our enrollment target, despite each recruitment method having limitations. Total variable costs of approximately 102,700wereincurredanddifferedonaperenrolledparticipantbasisacrossmethods:102,700 were incurred and differed on a per-enrolled participant basis across methods: 25.73 for targeted e-recruitment, 57.12forpaiderecruitment,and57.12 for paid e-recruitment, and 64.92 for in-person methods. Our sample differed from the national population in age, gender, race/ethnicity, education, and role in long-term care. Differences were also observed between online and in-person recruitment methods. Our results support the feasibility of enrolling a large number of long-term care workers in a randomized controlled trial to increase COVID-19 vaccine confidence. Findings build upon the evidence base for engaging this important population in research, a critical step to improving long-term care resident health and well-being. Results from our trial are anticipated in 2024

    Strain‐Promoted Cycloadditions in Lipid Bilayers Triggered by Liposome Fusion

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    Due to the variety of roles served by the cell membrane, its composition and structure are complex, making it difficult to study. Bioorthogonal reactions, such as the strain promoted azide-alkyne cycloaddition (SPAAC), are powerful tools for exploring the function of biomolecules in their native environment but have been largely unexplored within the context of lipid bilayers. Here, we developed a new approach to study the SPAAC reaction in liposomal membranes using azide- and strained alkyne-functionalized Förster resonance energy transfer (FRET) dye pairs. This study represents the first characterization of the SPAAC reaction between diffusing molecules inside liposomal membranes. Potential applications of this work include in situ bioorthogonal labeling of membrane proteins, improved understanding of membrane dynamics and fluidity, and the generation of new probes for biosensing assays

    National trends in emergency conditions through the Omicron COVID-19 wave in commercial and Medicare Advantage enrollees

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    Objective: To evaluate trends in emergency care sensitive conditions (ECSCs) from pre-COVID (March 2018–February 2020) through Omicron (December 2021–February 2022). Methods: This cross-sectional analysis evaluated trends in ECSCs using claims (OptumLabs Data Warehouse) from commercial and Medicare Advantage enrollees. Emergency department (ED) visits for ECSCs (acute appendicitis, aortic aneurysm/dissection, cardiac arrest/severe arrhythmia, cerebral infarction, myocardial infarction, pulmonary embolism, opioid overdose, pre-eclampsia) were reported per 100,000 person months from March 2018 to February 2022 by pandemic wave. We calculated the percent change for each pandemic wave compared to the pre-pandemic period. Results: There were 10,268,554 ED visits (March 2018−February 2022). The greatest increases in ECSCs were seen for pulmonary embolism, cardiac arrest/severe arrhythmia, myocardial infarction, and pre-eclampsia. For commercial enrollees, pulmonary embolism visit rates increased 22.7% (95% confidence interval [CI], 18.6%–26.9%) during Waves 2−3, 37.2% (95% CI, 29.1%–45.8%] during Delta, and 27.9% (95% CI, 20.3%–36.1%) during Omicron, relative to pre-pandemic rates. Cardiac arrest/severe arrhythmia visit rates increased 4.0% (95% CI, 0.2%–8.0%) during Waves 2−3; myocardial infarction rates increased 4.9% (95% CI, 2.1%–7.8%) during Waves 2−3. Similar patterns were seen in Medicare Advantage enrollees. Pre-eclampsia visit rates among reproductive-age female enrollees increased 31.1% (95% CI, 20.9%–42.2%), 23.7% (95% CI, 7.5%,–42.3%), and 34.7% (95% CI, 16.8%–55.2%) during Waves 2−3, Delta, and Omicron, respectively. ED visits for other ECSCs declined or exhibited smaller increases. Conclusions: ED visit rates for acute cardiovascular conditions, pulmonary embolism and pre-eclampsia increased despite declines or stable rates for all-cause ED visits and ED visits for other conditions. Given the changing landscape of ECSCs, studies should identify drivers for these changes and interventions to mitigate them

    Risicobeperking van ziekten en plagen bij energiezuinige maatregelen

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    This study gives an overview on the impact of climatic conditions, e.g. moisture deficit and CO2, on the plant defense system in the greenhouse. Higher CO2 dosages or increased moisture levels have a strong influence on the pest control. Partly, by direct effects on biological control agents and partly through effects on the plant quality. The outcome depends on the prey-predator system
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