1,720,966 research outputs found
Development of a mesoporous silica-based mid-infrared biosensor for the quantification FAME in jet fuel
Full text linkJet-Kraftstoff in Europa wird oft durch dieselben Pipelines und Tanker wie Biodiesel transportiert. Dies führt zu einer Kontamination des Kerosins mit Fettsäuremethylestern (FSME), was die Qualität des Kraftstoffs mindert. Daher ist es wichtig, FSME im Kerosin vor der Verwendung zu überwachen und zu quantifizieren. Die Messung wird normalerweise off-line in Testlabors durchgeführt. Ziel dieser Arbeit ist die Entwicklung eines Biosensors zur Quantifizierung von FSME, der at-line verwendet werden kann, um die Prüfung effizienter zu gestalten. Das Enzym Lipase soll für die selektive Reaktion von FSME in einer komplexen Matrix eingesetzt werden. Im mittleren Infrarotbereich können Biosensoren erfolgreich realisiert werden, indem die bioaktive Substanz (Lipase) im evaneszenten Feld von abgeschwächten Totalreflexions- (ATR) Kristallen immobilisiert wird, wodurch eine Echtzeitüberwachung der katalysierten Reaktion ermöglicht wird. Die Effektivität dieses Ansatzes kann durch den Einsatz von mesoporösen Schichten verbessert werden, um die Oberfläche und damit die Anzahl der bioaktiven Enzyme im spektroskopisch untersuchten Volumen erheblich zu erhöhen.Diese Arbeit zielte darauf ab, die Substratquantifizierung enzymatischer Reaktionen zu verbessern, wobei insbesondere die Hydrolyse und Aminolyse mittels FTIR-Spektroskopie untersucht wurden. Besonderes Interesse galt der Optimierung der Aminolyse-Reaktion von FSME, die durch eine Lipase katalysiert wurde, als Grundlage für den Biosensor. Eine umfassende Untersuchung geeigneter Lipase-Substrat-Paare wurde durchgeführt, um die effizientesten Paarungen zu bestimmen. Weiterhin wurden mesoporöse Siliciumdioxid-Filme, die auf eine Porengröße von ca. 8 nm und eine Schichtdicke von 500 nm optimiert wurden, auf Si-ATR-Kristalle aufgebracht. Lipase-Enzyme wurden dann auf diesen Siliciumdioxid-Filmen immobilisiert, wobei deren einzigartige Struktur genutzt wurde, um die Enzymadsorption zu erleichtern und weiterhin als Anreicherungsschicht für den Analyten zu dienen. Dieser Ansatz zeigt die Anwendbarkeit von mesoporösen Siliciumdioxid-Film-beschichteten ATR-Kristallen zur Überwindung von Herausforderungen, die mit traditionellen Biosensoren in der IR-Spektroskopie verbunden sind.Mit einem funktionierenden enzymatischen System, einer angemessenen mesoporösen Schicht und erfolgreicher Immobilisierung zeigen diese Erkenntnisse vielversprechende Fortschritte für die Biosensortechnologie, indem mesoporöse Siliciumdioxid-Filme und ATR-FTIR-Spektroskopie kombiniert werden, nicht nur zur Quantifizierung und in-situ Reaktionsüberwachung mittels IR, sondern auch zur Verbesserung der enzymatischen Sensortechnologie.Jet fuel in Europe is often transported though the same pipelines and tankers as biodiesel. This leads to the contamination of the kerosene with fatty acid methyl esters (FAME), which diminishes the quality of the fuel. Therefore, it is important to monitor and quantify the FAME in kerosene before usage. The measurement is usually performed off-line in test labs. The goal of this thesis is the development of a biosensor for the quantification of FAME which can be used at-line, making the testing more time efficient. The enzyme lipase should be used for selective reaction of FAME in a complex matrix. In the mid-infrared, biosensors can be successfully realized by immobilizing the bioactive substance (ipase) in the evanescent field of attenuated total reflection (ATR) crystals allowing for the real-time monitoring of the catalyzed reaction. The effectiveness of this approach can be enhanced by employing mesoporous layers to significantly increase the surface area and, thus, the number of bioactive enzymes in the spectroscopically probed volume.This study aimed to enhance the substrate quantification of enzymatic reactions, specifically investigating hydrolysis and aminolysis using FTIR spectroscopy. Of special interest was the optimization of the aminolysis reaction of FAME facilitated by a lipase as the foundation for the biosensor. A comprehensive study of suitable lipase-substrate pairs was performed to determine the most efficient pairings. Further, mesoporous silica films, which were optimized to attain pore sizes of approx. 8 nm and a layer thickness of 500 nm, were applied onto Si ATR crystals. Lipase enzymes were then immobilized onto these silica films, leveraging their unique structure to facilitate enzyme attachment and further serve as an enrichment layer for the analyte. This approach demonstrates the applicability of mesoporous silica film-coated ATR crystals in overcoming challenges associated with traditional biosensors in IR spectroscopy.With a functioning enzymatic system, an adequate mesoporous layer and successful immobilization, these findings hold promise for advancing biosensing capabilities by combining mesoporous silica films and ATR-FTIR spectroscopy, not only for quantification and in-situ reaction monitoring via IR but also enhancing enzymatic sensor technology
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
- …
