1,720,956 research outputs found
Structural studies of a Tremella fuciformis mushroom lectin: a novel protein with antitumoral properties
No full textLectins are carbohydrate-binding proteins of non-immune origin, widely distributed in all the living organisms. They play a role in different biological processes and, due to their carbohydrate specific binding, some lectins have been found to possess antitumoral properties. A particular case is the recognition of the T-antigenic determinant (Galβ1-3GalNAcα) on the malignant cell surfaces, which is present in 90% of human carcinomas. Upon binding to the carbohydrate, some lectins can cause apoptosis, cytotoxicity, inhibition of tumour growth, thus preventing the proliferation of tumoral cells. Considering the fact that these carbohydrates are masked on healthy cells, the highly specific carbohydrate-lectin interaction can be exploited to target only malignant cells. Although the function and the biological properties of several lectins have been determined, there are still many lectins that remain to be structurally and functionally characterized. As reported in the literature, some Tremella fuciformis proteins have been investigated for their potential therapeutical properties and in the light of this, the crude extract of this fungus was examined to assess the presence of lectins. A lectin of 11 KDa, named TFL, was isolated and purified from the dried fruiting bodies and used for testing several crystal screening conditions. The best crystals were grown in 0.1 M TRIS pH 8.5, 1.5 potassium phosphate dibasic, 1 % DMSO and the final data sets were collected at the ESRF of Grenoble, revealing the three-dimensional structure of the protein. TFL belongs to the space group P1211 and the cell parameters of the crystal are the following: a = 61.62 Å, b = 61.83 Å, c = 67.84 Å, with β = 106.87 °. The protein is a monomer, composed of six β-sheets (from A to F) that arrange to form the so called “β-barrel”. In addition, two α-helixes, named H1 and H2 can be recognized in the structure, which is also stabilized by the presence of two disulphide bridges that connect Cys 54 to Cys 70 and Cys 97 to Cys 100, respectively. Thermal protein stability was analyzed by means of differential scanning calorimetry, revealing that TFL does not undergo a two-state unfolding process and its denaturation is reversible, a feature that has been rarely observed for lectins before. In addition, chemical and pH-induced unfolding were investigated using fluorescence spectroscopy, highlighting the high stability of TFL in a wide range of conditions. Exploiting isothermal titration calorimetry, more information about sugar-binding were acquired, identifying N-acetylgalactosamine as the best candidate, which has micromolar affinity for TFL. It has also been observed that Tremella fuciformis lectin shows no cytotoxicity on malignant and healthy cells and interestingly, it seems to reduce skin malignant cells migration and to have a positive effect in the upregulation of certain genes involved in cancer arresting (SBPP1). In addition, immunomodulatory activity of TFL was analyzed by means of ELISA essay, resulting in the up-regulation of the most important inflammatory markers (IL-6, TNFα), that could be usefully exploited in order to kill intracellular microorganisms and to help the human body to develop a stronger tumoral resistance. In conclusion, this work provides a new and interesting insight into cancer treatment, being an essential prerequisite for future in vitro and in vivo experiments. The encouraging results obtained so far, alongside with the fact that TFL has been produced also heterologously in E.coli, pave the way for further studies, including the feasibility to perform mutagenesis and to explore the possibility to further encapsulate the protein inside tailor-made nanoparticles, with the aim of reducing the amount of protein used, increasing its therapeutical efficiency, and preventing side effects
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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