1,720,968 research outputs found
A droplet microfluidic redox sensor
No full textTotal free thiols are an important marker of the body’s redox state, which have shown correlations with disease severity and recovery in numerous conditions including COVID-19, sepsis and in renal transplant patients. Recent research has highlighted that increased insight may be gained by taking regular measurements to monitor trends in redox stressors such as disease, exercise, and hypoxia. However, conducting such studies is currently challenging due to the requirement for repeated venous blood sampling and intensive lab work. Droplet microfuidic sensors offer a platform for developing a point of care testing approach, using small sample volumes and automated systems to replicate laboratory testing. In this thesis, I had developed a small, portable droplet microfuidic sensor that can measure total free thiols in plasma, providing the reading in less than 10 minutes. This system used a novel method to introduce bumps into a PTFE fow channel to enhance the mixing of droplets containing complex biological fuids. The results in a range of real plasma samples showed equivalence with current standard laboratory assay, while reducing sample volume requirements nine-fold from 90 µl to 10 µl and fully automating the process. Integrated, membrane-based, plasma separation was developed, providing high-purity plasma from whole blood input. However, an immune response of platelets and white blood cells on contact with the membrane resulted in signifcant interference when measuring total free thiols in the output. An alternative capillary centrifuging strategy allowed testing of capillary blood samples collected by fngerprick lancing. The system was used to monitor total free thiols using fngerprick samples in healthy volunteers and revealed signifcant changes in total free thiols in response to food intake and exercise. This device will improve our ability to conduct physiological studies investigating total free thiols which could improve our understanding of redox physiology, which may ultimately improve medical care
Dataset in support of the thesis 'A droplet microfluidic redox sensor'
No full textA dataset to accompany the thesis 'A Droplet Microfluidic Redox Sensor'. Contains CSV files and the necessary processing code to extract the data forming the key results presented in the thesis. </span
A droplet microfluidic sensor for point-of-care measurement of plasma/serum total free thiol concentrations
No full textTotal free thiols are an important marker of the whole-body redox state, which has been shown to be associated with clinical outcome in health and disease. Recent investigations have suggested that increased insight may be gained by monitoring alterations of redox state in response to exercise and hypoxia and to monitor redox trajectories in disease settings. However, conducting such studies is challenging due to the requirement for repeated venous blood sampling and intensive lab work. Droplet microfluidic sensors offer an alternative platform for developing a point-of-care testing approach using small sample volumes and automated systems to complement or ultimately replace laboratory testing. Here we developed a small, portable droplet microfluidic sensor that can measure total free thiol concentrations in 20 μL human plasma (or serum) samples, providing a reading in less than 10 min. This system features a novel method to enhance the mixing of reagent and analyte in droplets containing viscous biological fluids. The results in a range of real-world human plasma samples showed equivalence with current standard laboratory assays while reducing sample volume requirements 9-fold and fully automating the process. Micro hematocrit capillaries allowed testing of capillary blood samples collected by fingerprick lancing. The system was used to monitor total free thiols using fingerprick samples in healthy volunteers and revealed significant changes in total free thiols in response to food intake and exercise. This device has the potential to improve our ability to conduct physiological studies of total free thiol level changes and improve our understanding of redox physiology, which may ultimately be applied in redox medicine to improve patient care
Development of an in situ droplet microfluidic autonomous sensor for total alkalinity in sea water
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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