1,720,957 research outputs found
Graphene Field-Effect Transistor for Biosensing: From Extracellular Vesicles Detection to Protein Conformational Changes Monitoring
No full textI Transistor a Effetto di Campo al Grafene (GFET) sono una tecnologia promettente nei biosensori grazie alle loro eccezionali proprietà elettriche, alta sensibilità e tempi di risposta rapidi. Questi dispositivi possono rilevare una vasta gamma di molecole biologicamente rilevanti. Le Vescicole Extracellulari (EV), considerate biomarcatori per malattie come il cancro, offrono nuove opportunità per diagnosi rapide e non invasive. In questa tesi, un biosensore basato su GFET, originariamente progettato per SARS-CoV-2, è stato adattato per rilevare le EV in diagnosi di cancro ovarico. Le EV sono state isolate e caratterizzate da colture cellulari, e le misurazioni elettriche sul marcatore CD63, associato alle EV, hanno mostrato alta specificità e sensibilità. Ciò è stato possibile grazie alla progettazione di un biorecettore ingegnerizzato, sviluppato combinando biologia sperimentale e computazionale, e potenziato dall’integrazione con il machine learning. Inoltre, la tecnologia GFET consente il monitoraggio in tempo reale delle interazioni molecolari, ideale per studiare i cambiamenti conformazionali delle proteine. A differenza dei metodi tradizionali, i GFET offrono un monitoraggio continuo delle transizioni dinamiche. In questo lavoro, abbiamo sviluppato un biosensore GFET per rilevare i cambiamenti conformazionali indotti dal calcio nella calmodulina (CaM). Questo studio evidenzia il potenziale dei GFET per la diagnostica e lo studio in tempo reale delle interazioni molecolari, aprendo la strada ai biosensori di nuova generazione.Graphene Field-Effect Transistors (GFETs) are emerging as a promising in biosensing due to their exceptional electrical properties, high sensitivity, and rapid response times. These devices can detect a broad range of biologically relevant molecules. Extracellular Vesicles (EV), considered as biomarkers for diseases such as cancer, offer new opportunities for rapid, non-invasive diagnostics, enabling early detection. In this thesis, a GFET-based biosensor originally designed for SARS-CoV-2, was used to detect EVs for ovarian cancer diagnosis. EVs were isolated and characterized from cell culture samples, and electrical measurements targeting the EV-associated marker CD63 showed high specificity and sensitivity. This was possible through the design of an engineered bioreceptor, developed by combining experimental and computational biology, further enhanced by machine learning integration. Beyond diagnostics, GFET technology also enables real-time monitoring of molecular interaction and dynamic processes, making it ideal for studying protein conformational changes. Unlike traditional methods that offer static snapshots, GFETs provide continuous monitoring of dynamic shifts. Using this approach, we developed a GFET-based biosensor to detect calcium-induced conformational changes in calmodulin (CaM), a key calcium sensor in eukaryotic cells. Both wild-type CaM and a calcium-binding-deficient mutant were purified, validated, and analyzed. Conformational changes in CaM were successfully detected with the GFET biosensor.
This work underscores the transformative potential of GFETs in disease diagnosis and the real-time study of molecular interactions, paving the way for next-generation biosensors
Unlocking the Potential of Field Effect Transistor (FET) Biosensors: A Perspective on Methodological Advances in Computational and Molecular Biology
Full text linkField-effect transistor (FET)-based sensors are increasingly gaining relevance in diagnostic, healthcare, and environmental monitoring applications. A FET operates by transducing chemical interactions between a surface-immobilized bioreceptor and the target analyte into a detectable electrical signal. FET biosensors can detect and monitor molecules (i.e., biomarkers, small molecules, viruses, bacterias) present in liquid samples, making a “liquid gate” configuration of FETs the most suitable approach. However, this FET architecture presents dimensional constraints that affect bioreceptors’ stability and immobilization in the liquid phase. To overcome these limitations, herein, a combination of computational and molecular biology techniques for improving bioreceptors' applicability in biosensing is proposed. This results in the optimized and problem-tailored protein receptors for specific FET biosensors applications, thus enhancing their overall performance. The interplay between the computational and experimental approaches will represent a ground-breaking solution for the development of next-generation biosensors
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
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