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Design and synthesis of new glucosamine derivatives for the application in transition-metal catalytic systems
Get PDFKobaltovi katalizatorji se v zadnjih letih vedno bolj uporabljajo za tvorbo vezi ogljik-ogljik. Prednost kobalta pred ostalimi prehodnimi kovinami je predvsem njegova dostopnost, nizka toksičnost ter nizka cena. Zaradi naštetih razlogov spadajo katalitski sistemi, ki kot katalizator uporabljajo kobaltove komplekse, med bolj ekološke. Reakcije z njimi potekajo v dokaj milih pogojih, za potek reakcije pa potrebujemo še bazo in ligand, s katerim kobalt tvori kompleks predhodno, ali pa in-situ. Tekom izdelave magistrske naloge smo sintetizirali nove derivate glukozamina kot ligande za katalitske sisteme. V teh sistemih z uporabo Grignardovih reagentov in s pomočjo kobalta in ligandov stereoselektivno tvorimo nove vezi ogljik-ogljik. Sintetizirali smo 8 potencialnih ligandov, od katerih smo nato tri uporabili v izbranem katalitskem sistemu.
Sintetizirane spojine smo testirali tudi na encimih acetilholinesteraza, butirilholinesteraza in monoaminooksidaza A in B. Zaviralno aktivnost sta izkazovali dve spojini, in sicer na encimu butirilholinesteraza.
Nazadnje smo ligandom določili tudi sposobnost kelacije nekaterih prehodnih kovin. Komplekse s kobaltom (Co2+) je tvorilo šest spojin, z železom (Fe2+) pa ena. Spojine, sposobne kelacije prehodnih kovin, se lahko potencialno uporabijo kot zdravilne učinkovine, kot kelatorji, ali pa kot učinkovine, kjer je prehodna kovina del zdravilne učinkovine in igra pri klinični aplikaciji ključno vlogo. Anorganska farmacevtska kemija je v uporabi sicer še vedno na drugem mestu za organsko kemijo, a številne raziskave v zadnjem desetletju dokazujejo njen potencial na številnih področjih medicine in farmacije.
Sintetizirane derivate glukozamina smo tako uporabili za tri različne namene:
- kot ligande v katalitskih sistemih, kjer smo tvorili nove vezi ogljik-ogljik- kot potencialne zaviralce encimov AChE, BChE, MAO-A in MAO-B- kot kelatorje nekaterih prehodnih kovin.Cobalt-based catalytic systems are being more widely used in the carbon-carbon bond formation. In comparison to some other transition metals, cobalt is easily accessible, has low toxicity and lower cost, which makes cobalt-based catalytic systems more eco-compatible and eco-friendly. Reactions take place under mild conditions. For the reaction to occur, a base and a ligand need to be added. The ligand forms a complex with the cobalt, either beforehand or in-situ. This Master\u27s thesis is focused on the design of new glucosamine derivatives, to be used as ligands in catalytic systems, where carbon-carbon bonds were formed stereoselectively, using Grignard reagents and cobalt as a catalyst. We synthesised 8 potential ligands, of which three were used as ligands in the catalytic system.
We tested the synthesised compounds on enzymes: acetylcholinesterase, butyrylcholinesterase, monoamino oxidase A and monoamino oxidase B. Two compounds showed inhibitory activity on butyrylcholinesterase.
Lastly, we determined the ligands\u27 chelating ability of certain transition metals. Six compounds formed complexes with cobalt (Co2+), whereas one compound formed complexes with iron (Fe2+). Compounds with chelating abilities can potentially be used as drugs – either as drugs that target metal ions in some form (chelators), or metal-based drugs, where the metal ion is crucial to the clinical application. Pharmaceutical industry is still dominated by drugs of organic origin, but numerous researches in the past decade have shown the potential of the medicinal inorganic chemistry.
Synthesised glucosamine derivates can potentially be used as:
- ligands in catalytic systems, where carbon-carbon bonds are formed- inhibitors for AChE, BChE, MAO-A and MAO-B- chelators of certain transitiona metals
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
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