1,720,955 research outputs found
A Raman and SERS study on the interactions of aza[5]helicene and aza[6]helicene with a nanostructured gold surface
No full textWe studied the interaction of 5-aza[5]helicene and 5-aza[6]helicene with gold nanostructured substrates by SERS spectroscopy and DFT calculations. By comparing Raman and SERS experiments we observe significant changes for the normal modes involving nitrogen. This behavior, together with further evidence coming from SERS experiments carried out on the quaternary salts of the same azahelicenes, clearly highlight the direct interaction of nitrogen with the gold surface. DFT calculations on azahelicene models interacting with Au20 gold clusters reveal the charge transfer between azahelicene and gold. The information obtained from this study is useful in the field of sensor applications, where knowledge of the molecular mechanisms of interaction is fundamental for an appropriate design of the device
SERS assessment of carbamazepine in methanol, chloroform and patient samples using AU sensors with optimized surface nanostructrure
No full textLAUREA MAGISTRALEL'oggetto del presente lavoro è la valutazione quantitativa della concentrazione di carbamazepina, un farmaco antiepilettico molto diffuso, in diverse soluzioni. Partendo da soluzioni semplici, la ricerca si è spostata verso il caso reale, con l'obiettivo di conseguire il monitoraggio terapeutico del farmaco. La tecnica utilizzata per la valutazione della concentrazione di carbamazepina è stata la Raman Enhanced Surface Spectroscopy (SERS).
La prima parte della tesi è dedicata alla parte teorica. Viene fornita una certa conoscenza circa la produzione dei sensori. Poi la teoria della spettroscopia Raman e dell'effetto SERS sono rapidamente riportati.
La seconda parte riguarda il lavoro sperimentale. Sono state analizzate soluzioni di carbamazepina in metanolo e in cloroformio. Si è quindi preso in considerazione l'estratto in metanolo da plasma, una soluzione intermedia ottenuta nei laboratori ospedalieri, e una grande attenzione è stata data ai problemi derivanti dall'analisi di questo tipo di campione.
Il lavoro sperimentale è continuato analizzando i sensori. Il metodo di produzione è stato modificato per ottenere substrati in grado di superare i problemi riscontrati. I nuovi sensori sono stati caratterizzati dal punto di vista ottico e morfologico. Un semplice modello è stato costruito per spiegare l'effetto del nuovo metodo di produzione sui substrati. La performance SERS dei sensori è stata analizzata e sono stati selezionati i sensori ottimali per eseguire le misure sull'estratto dal plasma, ottenendo risultati promettenti.The subject of the present work is the quantitative evaluation of the concentration of carbamazepine, a widespread anti-epileptic drug, in different solutions. Starting from simple solutions, the research moved towards the real case, with the aim of achieving the therapeutic drug monitoring. The technique used for the assessment of carbamazepine concentration was Surface Enhanced Raman Spectroscopy (SERS).
The first part of the thesis is dedicated to the theoretical part. Some insight is given about the production of the sensors. Then the theory of Raman spectroscopy and SERS effect are quickly illustrated.
The second part deals with the experimental work. Solutions of carbamazepine in methanol and in chloroform were analysed. Extract in methanol from plasma, an intermediate solution obtained in hospital laboratories, was then considered and great attention was given to the prob-lems arising from the analysis of this kind of sample.
The experimental work continued analysing the sensors. The production method was modified in order to obtain substrates able to overcome the problems found. The new sensors were characterized optically and morphologically. A simple model was built to explain the effect of the new production method on the substrates. The SERS performance of the sensors was analysed and the optimal sensors were selected to perform the measures on the extract from plasma, reaching promising results
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
- …
