1,720,957 research outputs found
Development of a Method for the Quantification of Caseinate Traces in Italian Commercial White Wines Based on Liquid Chromatography-Electrospray Ionization-Ion Trap-Mass Spectrometry
No full textCytosine to uracil conversion through hydrolytic deamination of cytidine monophosphate hydroxy-alkylated on the amino group: a liquid chromatography – electrospray ionization – mass spectrometry investigation.
No full textA novel pathway for cytosine to uracil conversion performed in a micellar environment, leading to the generation of uridine
monophosphate (UMP), was evidenced during the alkylation reaction of cytidine monophosphate (CMP) by dodecyl epoxide.
Liquid chromatography-electrospray ionization – ion trap - mass spectrometry was used to separate and identify the reaction
products and to follow their formation over time. The detection of hydroxy-amino-dodecane, concurrently with free UMP, in
the reaction mixture suggested that, among the various alkyl-derivatives formed, CMP alkylated on the amino group of
cytosine could undergo tautomerization to an imine and hydrolytic deamination, generating UMP. Interestingly, no evidence
for this peculiar conversion pathway was obtained when guanosine monophosphate (GMP), the complementary ribonucleotide
of CMP, was also present in the reaction mixture, due to the fact that NH2-alkylated CMP was not formed in this case. The last
finding emphasized the role played by CMP–GMP molecular interactions, mediated by a micellar environment, in hindering the
alkylation reaction at the level of the cytosine amino group
Improved specificity of cardiolipin peroxidation by soybean lipoxygenase: a liquid chromatography - electrospray ionization mass spectrometry investigation
No full textPeroxidation catalysed by Soybean Lypoxigenase was performed on tetralinoleyl-cardiolipin with the aim of generating
selectively oxidized products, to be used subsequently as standards for studies on cardiolipin oxidation. The reaction products
were characterized by LC-ESI-MS and MS/MS, and the process was found to link a hydroperoxylic group on one or more linoleic
chains of cardiolipin, up to a total of four groups per molecule. Interestingly, the incidence of other oxidized products, like
those arising from multiple hydroxylation or mixed hydroxylation-hydroperoxydation, previously observed after the chemical
oxidation of the same cardiolipin, was found to be negligible. Moreover, evidences for the presence of the hydroperoxylic
group(s) almost exclusively on carbon 13 of the linoleic chain(s) were obtained by MS/MS measurements. The enzymatic approach,
integrated with a preparative separation step, which could be developed by adapting the chromatographic conditions
adopted in the present work for analytical purposes, represents a promising strategy for the synthesis of highly specific monoor
multi-peroxidated derivatives of cardiolipins
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
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