1,721,055 research outputs found
Advanced materials based on carbon dots for technological applications
Full text linkI Carbon Dots (CD), una recente classe di nanoparticelle carbonacee biocompatibili di dimensioni di soli pochi nm, hanno il potenziale di permeare nel panorama attuale dei materiali fluorescenti e trasformare diversi settori tecnologici, grazie alla loro particolare combinazione di sostenibilità e fluorescenza visibile. Infatti, tali nanostrutture zero-dimensionali possono essere considerate l'alternativa a base di carbonio ai quantum dots semiconduttori, premiati con il Nobel per la Chimica nel 2023. Rispetto ai quantum dots, tuttavia, persistono delle sfide a causa della limitata comprensione dei meccanismi chimici e fotofisici che regolano la sintesi dei CD e le loro proprietà ottiche. La ricerca attuale mira a sviluppare metodi sintetici per la preparazione controllata di CD con proprietà ottiche su misura, mirando in particolare all'intensa emissione rossa.
Questo studio ha affrontato tali attuali sfide che ancora ostacolano l'uso pervasivo dei CD nei dispositivi tecnologici. Più specificamente, ha analizzato diverse strategie sintetiche "bottom-up", migliorando metodologie esistenti o contribuendo allo sviluppo di nuovi percorsi sintetici razionali per i CD. Sono state affrontate e ottenute componenti di emissione rossa potenziate sia attraverso approcci sintetici che tramite accoppiamento post-sintetico con nanoparticelle metalliche plasmoniche. Le proprietà fisico-chimiche dei CD sintetizzati sono state accuratamente esaminate, con particolare attenzione alla dinamica dell'emissione fotofisica. Le indagini sulla resistenza dei CD alla degradazione fotochimica sono cruciali per chiarire gli aspetti tecnologici chiave associati alla loro implementazione nei dispositivi e per chiarire il contributo dei fluorofori molecolari all'emissione delle nanoparticelle. Infine, sono state selezionate due applicazioni tecnologiche nell'illuminazione e nei dispositivi di rilevamento chimico, per la loro rilevanza per l'innovazione industriale, e il potenziale applicativo dei CD sintetizzati in questi campi è stato dimostrato. Ciò ha coinvolto la fabbricazione di nanocompositi polimerici per la conversione del colore, di mezzi attivi al laser e di una piattaforma portatile a fluorescenza per il rilevamento del pH e dell'attività antiossidante di composti chimici.
In definitiva, questo lavoro si unisce agli sforzi della comunità di ricerca per sfruttare le proprietà di emissione dei CD nei procedimenti "bottom-up", fornendo prospettive e strategie preparative originali mentre evidenzia considerazioni cruciali. Nelle sezioni applicative, ha contribuito a facilitare procedure di lavorazione basate su soluzione di queste nanoparticelle, integrando quando possibile, procedure sperimentali con ottimizzazioni numeriche, al fine di dimostrare il potenziale eccezionale dei CD per il mondo tecnologico.Carbon Dots (CDs), a recent class of biocompatible carbonaceous nanoparticles of only few nm in size, have the potential to permeate into the current scenario of lighting materials and transform diverse technological sectors, thanks to their unique blend of sustainability and attractive visible fluorescence. Indeed, such zero-dimensional nanostructures can be considered the carbon-based alternative to semiconductor quantum dots, awarded with the Nobel Prize in Chemistry in 2023. Respect to the quantum dots, however, challenges persist due to limited understanding of the chemical and photophysical mechanisms governing CD synthesis and optical properties. Current research aims to develop synthetic methods for controlled preparation of CDs with tailored optical properties, particularly targeting intense red emission.
This study addressed such current challenges still hindering pervasive use of CDs in technological devices. More specifically, it analyzed different bottom-up synthetic strategies, improving currently existing methodologies or contributing to develop new rational synthetic routes for CDs. Enhanced red emission components was tackled and obtained both via synthetic approaches and through post-synthetic coupling with plasmonic metal nanoparticles. Physicochemical properties of the synthesized CDs were accurately scrutinized, with particular attention on photophysical emission dynamics. Investigations into the resistance of CDs to photochemical degradation are pivotal for elucidating key technological aspects associated with their implementation in devices and for clarifying the contribution of molecular fluorophores to nanoparticle emission. Finally, two technological applications in lighting and chemical sensing devices, were selected for their relevance for industrial innovation and the applicative potential of synthesized CDs in these fields was demonstrated. This involved the fabrication of polymer color-conversion nanocomposites, of laser active media and of a fluorescence based portable platform for sensing of pH and antioxidant activity of chemical compounds.
Ultimately, this work joins the research community’s effort to exploit the emission properties of CDs in bottom-up procedures, providing original perspectives and preparative strategies while highlighting crucial considerations. In the applicative sections, it contributed to facilitate solution-based processing procedures of these nanoparticles, integrating whenever possible experimental procedures with numerical optimizations, at the aim of proving the outstanding potential of CDs for the technological world
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
Semiconductor nanocrystals/ metal phthalocyanines hybrid junctions: a photoelectrochemical and spectroscopic investigation
No full textAuthor-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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