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Paper-based cationic isotachophoretic platform for detection of disease markers
Get PDFThe objective of this study is two-fold: to develop a method to electrophoretically concentrate positively charged gold nanoparticles (GNPs) using paper-based cationic isotachophoresis (ITP), as well as explore an approach for modifying negatively charged GNPs with avidin to produce conditions favorable to cationic ITP on the paper-based platform. The rationale is that ITP can be integrated into lateral flow assay technology to enhance the sensitivity of the analytical technology. This work describes and demonstrates important factors to consider when designing an ITP system including the selection and modification of the reaction media, and the design of the ITP discontinuous buffer system including the selection of the leading and terminating ions, counterions, pH, and ionic strength of the system. Furthermore, this work demonstrates the effectiveness of using avidin to alter the electrophoretic mobility of biotinylated GNPs by reversing the negative surface charge to favor cationic ITP conditions. This study demonstrates that the techniques described have potential to enhance the effectiveness of paper-based point-of-care technology and bring this this technology closer to practical applications
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LATERAL CATIONIC ISOTACHOPHORESIS-GUIDED MIGRATION ANALYSIS (LIGMA) FOR NEXT GENERATION LATERAL FLOW ASSAYS
Get PDFThis dissertation presents the development and validation of a novel diagnostic platform integrating cationic isotachophoresis (ITP) with lateral flow assays (LFAs) to overcome the limitations of traditional paper-based diagnostic devices. By enhancing analyte preconcentration and separation, this work addresses the longstanding challenges of sensitivity and specificity in point-of-care (POC) testing for low-abundance biomarkers in complex biological samples.Chapter 1 introduces the constraints of conventional LFAs, including their reliance on passive capillary flow and susceptibility to interference from high-abundance serum pro-teins, which hinder their diagnostic accuracy. It further highlights the untapped potential of cationic ITP, particularly for the analysis of negatively charged proteins, as a transformative approach to improving assay performance. Chapter 2 details the modification of nitrocellulose membranes to enhance biomolecule retention and minimize non-specific interactions, ensuring compatibility with the strong electrophoretic forces inherent to ITP. These modifications laid the groundwork for robust and stable capture-line immobilization under cationic ITP conditions. Chapter 3 provides a systematic guide to designing and optimizing discontinuous electrolyte systems essential for ITP. This chapter evaluates the effects of buffer composition, ionic strength, and pH on analyte stacking and separation, demonstrating how these parameters impact the performance of cationic ITP-enhanced LFAs. Chapter 4 focuses on the synthesis and engineering of avidin-functionalized gold nanoparticles as modular cationic probes. Covalent functionalization strategies were employed to stabilize the bio-nano interface under dynamic ITP conditions, ensuring the reliable migration of target-probe complexes. Zeta potential analyses confirmed the capability of avGNPs to modify the charge of biotinylated protein complexes, rendering them suitable for cationic ITP while maintaining robust signal generation. Chapter 5 validates the platform’s performance in simulated serum samples, demonstrating a limit of detection (LOD) of 1.97 nM and a limit of quantification (LOQ) of 4.12 nM for human IgG. These results represent a 10-fold improvement in sensitivity compared to traditional LFAs, achieved with minimal sample volume (1 μL) and rapid assay times (<2 minutes). The chapter also describes the construction of a portable, battery-operated system for field-deployable applications, emphasizing its potential for resource-limited settings. Finally, Chapter 6 summarizes the findings, underscoring the potential of cationic ITP-enhanced LFAs as a next-generation diagnostic platform. Recommendations for future work include expanding the scope to multiplex detection, higher sample volumes, and diverse analytes such as nucleic acids, extracellular vesicles, and whole cells, as well as integration with complementary sensitivity-enhancing methods.This work demonstrates a significant step forward in the field of paper-based diagnostics, offering a modular, sensitive, and rapid solution for addressing the limitations of conventional LFAs while maintaining their simplicity and affordability
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
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