1,720,955 research outputs found
Progettazione, sintesi e applicazione di nanoparticelle inorganiche-organiche protette da leganti fluorurati come nanomateriale per imaging e terapia
No full textNegli ultimi decenni la nanomedicina è stata oggetto di un aumentato interesse dal punto di vista sia della ricerca che di applicazioni pratiche sul campo. In particolare, uno degli obiettivi cardine della nanomedicina è lo sviluppo di nanosistemi per teranostica capaci di essere impiegati sia in diagnosi che in terapia. Tra le diverse tecniche di diagnostica, la risonanza magnetica nucleare (MRI) rappresenta la scelta di maggiore successo perché fornisce informazioni anatomiche dettagliate del paziente. Tuttavia, l’imaging diagnostico convenzionale basato sulla MRI al protone soffre di importanti limiti come, per esempio, il forte segnale di background e la necessità di alte dosi di agenti di contrasto paramagnetici. Un’alternativa che ha mostrato del potenziale rispetto all’approccio convenzionale è la 19F MRI, una tecnica che si basa sul 19F, che è quasi del tutto assente nei tessuti umani, e per questo motivo non soffre dell’interferenza causata dal segnale di background, ma richiede tuttavia l’uso di agenti di contrasto fluorurati. Al momento, la mancanza di validi agenti di contrasto per 19F MRI risulta essere uno dei principali colli di bottiglia che rallentano la sua applicazione in campo clinico. Questo lavoro si pone come obiettivo di trattare questo punto sviluppando due nuovi sistemi fluorurati: i) nanoparticelle d’oro protette da leganti fluorurati e ii) micelle fluorurate. Lo sviluppo di entrambi i sistemi si basa principalmente sull’impiego di perfluoropolyetilene glycole 600 come elemento costitutivo principale per fornire il segnale 19F NMR richiesto. Inoltre, i precedenti lavori del nostro gruppo hanno determinato che nanosistemi costituiti da nanoparticelle d’oro protette da leganti fluorurati potrebbero avere il potenziale di legare delle piccole molecole idrofobiche, come ad esempio farmaci, potendo svolgere perciò anche il ruolo di sistemi concepiti per il drug delivery. Le nanoparticelle d’oro fluorurate sviluppate in questo lavoro sono state ideate per fornire una migliore performance come agenti di contrasto per 19F NMR e come drug carrier, rispetto ai design precedenti. Il secondo nanosistema trattato in questo lavoro consiste di micelle fluorurate ottenute da due innovativi copolimeri fluorurati, sviluppati, sintetizzati e caratterizzati in questo lavoro, formati da una catena alchilica idrofobica, una porzione fluorurata e una catena di PEG di lunghezza variabile. La presenza dell’ambiente fluorurato nelle micelle fa supporre che questo possa comportarsi come lo strato auto-assemblato delle nanoparticelle fluorurate, ovvero come un ambiente idrofobico per poter ospitare eventuali farmaci. Le informazioni e conoscenza acquisita durante la formazione delle micelle fluorurate sarà fondamentale per lo sviluppo di un altro nanosistema ibrido organico-inorganico che consiste in molecole anfifiliche fluorurate che racchiudono nanocristalli di rame solfuro al loro interno, al fine di combinare applicazioni per 19F MRI e terapia fototermica plasmonica (PPTT). Per concludere, in questo lavoro viene discusso un metodo per la dispersione di cristalli di rame solfuro attraverso una reazione di scambio con un tiolo fluorurato, sintetizzato nell’ambito di questo lavoro.Nanomedicine has been the subject of increasing interest in the last decades from the point of view of both basic research and advanced real-field applications. In particular, one of the important goals of nanomedicine is the development of theranostic nanosystems enabling to carry out diagnostic investigations while simultaneously acting as therapeutics. Among diagnostic techniques, magnetic resonance imaging (MRI) represents the choice of election because it provides detailed anatomical information. However, the conventional diagnostic imaging based of proton MRI suffers of some limitations such as the strong background signal and the need of paramagnetic contrast agents at high doses. An alternative MRI approach that has shown promise is 19F MRI, this technique is based on 19F, which is virtually absent from human tissues, and therefore it does not suffer from interfering background signals but requires the use of fluorinated contrast agents. At present, the lack of good contrast agents for 19F MRI is one of the bottlenecks hindering its clinical application. This work addresses this point by developing two fluorinated nanosystems: i) gold nanoparticles protected by fluorinated ligands and ii) fluorinated micelles. The design of both systems rely primarily on the use of perfluoropolyethylene glycol 600 as a building block to provide the necessary 19F MRI signal. Moreover, previous work from this group pinpointed that gold nanoparticles protected by fluorinated ligands can be potentially useful also as nanosystems capable of binding small hydrophobic drug-like molecules, therefore acting as drug delivery systems. The fluorinated gold nanoparticles developed in this work were conceived to deliver improved 19F MRI and drug carrier performance compared to previous designs. The second nanosystem, discussed in this work consists of fluorinated micelles obtained by using two novel fluorinated copolymers, hereby designed, synthesized and characterized, featuring a hydrophobic alkyl chain, a perfluorinated polymer moiety and a pegylated chain of variable length. It is anticipated that the fluorous environment of the micelles could act, similarly to the monolayer of fluorinated gold nanoparticles, as a hydrophobic environment to be loaded with putative drugs. The information and knowledge acquired on the fluorinated micelles will be instrumental also to the development of another hybrid organic-inorganic nanosystems consisting of fluorinated amphiphiles incapsulating copper sulfide nanocrystals in order to combine 19F MRI applications with plasmonic photothermal therapy (PPTT). Finally, a two-phase ligand exchange method with a fluorinated thiol is discussed for the dispersion of copper sulfide nanocrystals combined with 19F MRI
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
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