1,721,051 research outputs found
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
A Paper-Based Breast Co-Culture Model to Study Direct and Indirect Effects of Endocrine Disrupting Chemicals on Estrogen Signaling
Get PDFThree-dimensional (3D) cell culture platforms better recreate the complex microenvironment and cell-cell signaling gradients characteristic of in vivo tumors than monolayer cultures on plasticware. While in vitro co-culture models of stromal cells and ER(+) carcinoma cells have been developed to study tumor responses, there is a lack of detailed characterization of the expression and activity of aromatase enzyme in mammary fibroblasts in 3D environments. Aromatase converts androgens to estrogen. In this study, I quantify aromatase activity in stromal reductive mammary fibroblasts (RMFs) and estrogen receptor alpha (ERα) transactivation in a breast carcinoma cell line in 2D, 3D, and co-culture platforms. When treated with the aromatase inducers genistein and quercetin, we observed increased E2 synthesis in all culture formats containing RMFs. The 2D monocultures had much higher aromatase activity than 3D monocultures; the greatest increase in activity occurred in the co-cultures. Our results highlight the use of 3D breast cancer models as an improvement over traditional 2D cultures and a useful and efficient alternative to in vivo models.Bachelor of Art
Azide-Alkyne Cycloaddition Click Reactions on Amorphous Carbon Thin Films
Get PDFAmorphous carbon (aC) thin films are chemically stable films that can be functionalized through the formation of carbon-carbon or carbon-heteroatom bonds. Unlike other materials whose surface chemistries are labile under aqueous conditions, carbon surfaces are able to retain their functional groups when exposed to acidic or basic environments. The inherent stability of carbon materials, and the chemistries used to modify their surfaces, are ideal for generating functional materials such as supports for the attachment of photocatalysts. We present here an approach to terminate these films with azides. Utilizing copper-catalyzed azide-alkyne cycloaddition click chemistry, we demonstrate an approach for the selective and stable covalent attachment of a redox active complex, ferrocene, to the surface of these thin films. This reaction provides an efficient and flexible means for attaching a variety of alkyne-containing molecules to the surface of a thin film. XPS and electrochemical analyses confirm the presence of these various functional groups and demonstrate the necessity of the azide group in order for the click reaction to occur.Bachelor of Scienc
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
A Paper-Based Transwell Assay to Study Cancer-Cell Invasion in 3D
Get PDFCellular invasion is the gateway to metastasis, the leading cause of cancer-related deaths today. Therefore, in the fight against cancer, it is crucial to better understand the cues and conditions under which cellular invasion occurs. Such an understanding has the potential to lead to therapeutic treatments capable of halting a tumor in its progression towards a metastatic state. A popular current method of studying invasion is the modified Transwell assay, comprised of two chambers separated by a matrix-coated membrane through which cells can migrate in response to various chemokines. Although Transwell assays are readily available, customizable and provide easily interpretable data, they are expensive and offer little flexibility in assay setup. Here, we present a paper-based variation of the Transwell assay capable of generating similar datasets with equal reproducibility to the traditional setup at a fraction of the cost.Bachelor of Art
Development of an in vitro Pipeline to Detect and Quantify Herb-Drug Interactions
No full textHerb-drug interactions occur when a drug and herb are simultaneously ingested. When both the herb and the drug share a phase I or phase II metabolic enzyme target, enzyme induction or inhibition could be affected. This effect could alter the metabolic pathway of these and other xenobiotics, resulting in potentially toxic outcomes. As natural products become more widely used, it is important to understand how herb-drug interactions impact the metabolism of prescription medications. This work presents a method to study herb-drug interactions in the liver by evaluating a panel of metabolic enzymes. HepaRG cells were dosed with St. John’s wort and buspirone, an herb-drug combination that has been found to exhibit in vivo interactions. Metabolic enzyme activity was measured by an 8-in-1 assay in which cells are dosed with FDA-recommended substrates of 8 phase I and phase II metabolic enzymes. SJW and buspirone were shown to display antagonism on CYP2D6 and dose-dependent effects on CYP3A4 and UGT. Our results show that this method could be used to evaluate herb-drug interactions that have physiological relevance to metabolism.Bachelor of Scienc
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