975 research outputs found

    Field aligned current observations in the polar cusp ionosphere

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    Vector magnetic field measurements made during a sounding rocket flight in the polar cusp ionosphere show field fluctuations in the lower F-region which are interpreted as being caused by the payload's passage through a structured field aligned current system. The field aligned currents have a characteristic horizontal scale size of one kilometer. Analysis of one large field fluctuation gives a current density of 0.0001 amp/m sq

    Engineering new approaches for pathogen separation and detection to tackle antimicrobial resistance

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    Sepsis and antimicrobial resistance are global health crises. Sepsis, defined as a lifethreatening, dysregulated host response to infection, is responsible for one fifth (11 million) of all global deaths. The importance of immediate antimicrobial therapy in sepsis management is well documented, with 80% of patients surviving if they receive adequate antimicrobial therapy within one hour of documented hypotension. For each hour of subsequent delay for the following 6 hours there is an associated decrease in survival of 7.6%; at this rate, the chance of surviving more than 30 hours is less than 10%. This reliance on rapid, broad spectrum antimicrobial therapy necessary to treat sepsis accelerates the spread of resistance which is predicted to result in one death every 3 seconds due to a drug-resistant infection by 2050, resulting in 10 million more global deaths each year. Rapid and accurate pathogen identification remains a significant challenge in sepsis management due to the low concentration of pathogens in the bloodstream (1-1000 colony forming units/ml). This necessitates a lengthy blood culture step which typically takes 1-5 days. This thesis addresses the diagnostic bottleneck in sepsis treatment by exploring innovative methods for pathogen detection and separation. Focusing on the Glasgow Royal Infirmary’s clinical diagnostics workflow, I aimed to develop a novel sample preparation assay for blood samples by leveraging Toll-like Receptors 2, 4 and 9. These receptors, known for their broad pathogen recognition capabilities, were investigated for their potential to bind and detect Gram-positive bacteria, Gram-negative bacteria, and microbial DNA directly from blood samples. By exploiting the advantages of imaging flow cytometry for high-throughput detection of small particles, I developed and optimised assays to accurately quantify the binding capacity of TLRs to whole bacteria, and pathogen DNA. This work highlights the diagnostic and therapeutic potential of Toll-like receptors to be used, not only for pathogen detection, but also as possible biomarkers for the sepsis immune response, offering a novel, double-edged approach to diagnostics. Further optimisation may one day reduce the need for lengthy blood cultures, facilitating antimicrobial stewardship and helping pave the way for more effective sepsis management

    Genotype-Climatic and Other Interaction Effects for Productive Responses in Holsteins

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    Season of calving had important effects on the shape of the lactation curve, affecting peak milk yield, persistency, and lactation lengths in a Louisiana Holstein herd. Feeding regime and age at calving also had marked effects. Plane of nutrition appeared to have more important effects on components of the lactation curve than did season of calving. Most interaction effects were small. Lactation milk yield for Holstein cows in five Louisiana herds calving in the hot season of the year was consistently from 200 to 300 kg (5 to 8%) less than that for cows calving during cool and mild seasons. Yields during the first 90 days of lactation were 10 to 14% less. Interactions of sire by season of calving for part and whole lactation milk and milk fat yields accounted for less than 1% of the total variance. Interactions of cow by season of calving were of the same general magnitude. Thus, genotype-climatic interactions for milk production for Holstein cattle under Louisiana conditions are not important enough to consider in the selective breeding program. © 1974, American Dairy Science Association. All rights reserved

    “It sets boundaries making your life personal and more comfortable”: understanding young people’s privacy needs and concerns

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    Children and young people are prolific digital users, making up a third of the world's online users [1] and engaging with the digital world in different and distinct ways. However, their unique understandings and perspectives are often not considered in debates and discussions around privacy and security [2]. This article outlines a youth-centric notion of digital privacy and guiding principles around privacy developed by young people from Antigua and Barbuda, Australia, Ghana, and Slovenia

    Preliminary Investigation of Novel Bone Graft Substitutes based on Strontium-Calcium-Zinc-Silicate Glasses

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    Bone graft procedures typically require surgeons to harvest bone from a second site on a given patient (Autograft) before repairing a bone defect. However, this results in increased surgical time, excessive blood loss and a significant increase in pain. In this context a synthetic bone graft with excellent histocompatibility, built in antibacterial efficacy and the ability to regenerate healthy tissue in place of diseased tissue would be a significant step forward relative to current state of the art philosophies. We developed a range of calcium-strontium-zinc-silicate glass-based bone grafts and characterized their structure and physical properties, then evaluated their in vitro cytotoxicity and in vivo biocompatibility using standardized models from the literature. A graft (designated BT109) of composition 0.28SrO/0.32ZnO/0.40 SiO2 (mol fraction) was the best performing formulation in vitro shown to induce extremely mild cytopathic effects (cell viability up to 95%) in comparison with the commercially available bone graft Novabone® (cell viability of up to 72%). Supplementary to this, the grafts were examined using the standard rat femur healing model on healthy Wister rats. All grafts were shown to be equally well tolerated in bone tissue and new bone was seen in close apposition to implanted particles with no evidence of an inflammatory response within bone. Complimentary to this BT109 was implanted into the femurs of ovariectomized rats to monitor the response of osteoporotic tissue to the bone grafts. The results from this experiment indicate that the novel grafts perform equally well in osteoporotic tissue as in healthy tissue, which is encouraging given that bone response to implants is usually diminished in ovariectomized rats. In conclusion these materials exhibit significant potential as synthetic bone grafts to warrant further investigation and optimisation. © 2008 Springer Science+Business Media, LLC

    RSAT™ process development for post-combustion CO2 capture: Scale-up from laboratory and pilot test data to commercial process design

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    AbstractIt is believed that a RSAT™ (Regenerable Solvent Absorption Technology) process is the most viable nearterm technology for post-combustion CO2 capture from power plant flue gas. The Babcock & Wilcox Power Generation Group, Inc. (B&W) has deployed a suite of research tools to evaluate and develop the CO2 scrubbing technology, including laboratory, pilot-scale, and simulation modeling capabilities. Since the construction and operation of test facilities require significant resources, it is essential to effectively utilize these research tools by choosing a scale-up approach which provides robust design data for a commercial process while minimizing the amount of experimentation required.The scale-up protocol used for RSAT CO2 scrubbing processes was rigorously developed using rate-based modeling concurrent with acquiring fundamental laboratory and pilot plant data for process validation. These development activities were not conducted in series but rather overlapped to yield an optimized commercial CO2 scrubbing process in a reasonable time frame with a high degree of design confidence [1,2].This paper presents the scale-up protocol used in evaluating the RSAT process which encompasses both laboratory and pilot-scale testing as well as rate-based modeling to achieve a commercial-scale RSAT process design. This document demonstrates the qualification of test data from a packed tower scale-up point of view. Solvent screening research activities recently conducted within B&W successfully demonstrate the scale-up protocol used for RSAT process development. The time and cost of process development can be significantly reduced through rigorous rate-based modeling in conjunction with laboratory experiments and pilot plant validation
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