1,720,958 research outputs found
Phenilpropanoate identification in young wheat plants by liquid chromatography/tandem mass spectrometry: monomeric and dimeric compounds
No full textMetabolomic approach has become a very important tool for determining the actual gene expression and protein activity. Metabolism via the shikimate pathway in plant gives rise to a large number of aromatic compounds, including p-hydroxycinnamates, which are mainly associated with their cell walls in complex structures, ester-linked to heteroxilans. In this work, ferulate dehydrodimers and related compounds were extracted from the cellwalls of young lyophilized wheat plants with 2mol/l NaOH for 4 h at 25 ?C under N2. After solid phase extraction, samples were analysed by high-performance liquid chromatography-quadrupole-linear ion trap tandem mass spectrometry with the electrospray source operating in negative mode. Nineteen dehydrodiferulates, 2 hydrate forms, 3 oxo- forms, 2 decarboxilated forms and 1 dihydroxysinapate, were identified bymass spectra interpretation. In addition, five mixed dehydrodimers of ferulic-sinapic, ferulic-coumaric and ferulicsyringic acids were also identified. Reproducibility of peak areas was usually better than 10% but some minor components which may be procedural artefacts, although relativelymild conditions were used. Copyright (C) 2010 John Wiley & Sons, Ltd
Existence of hybrid structures in cationic liposome/DNA complexes revealed by their interaction with plasma proteins
No full textThe self-assembling of cationic liposomes (CLs) and DNA can give rise to a variety of nanostructures and morphologies. Multilamellar complexes are made of DNA intercalated between opposing lipid bilayers, while clusters formed by intact vesicles may exist as 'beads-on-a-string' (i.e. CLs attached to a string of DNA). Precise knowledge of the structure and morphology of complexes is relevant in many biological important processes such as gene delivery. Here dynamic light scattering, zeta potential, synchrotron small angle X-ray scattering and one-dimensional polyacrylamide gel electrophoresis were performed to investigate the equilibrium structure, morphology and interactions with plasma proteins of lipoplexes made of the cationic lipid (3β-[N-(N′,N′-dimethylaminoethane)-carbamoyl])-cholesterol (DC-Chol), the zwitterionic lipid dioleoylphosphatidylethanolamine (DOPE) and DNA. Results show that DC-Chol-DOPE/DNA complexes are multilamellar systems with DNA protected by cationic lipids. On the other hand, the 'protein corona' associated to lipoplexes after interaction with human plasma was found to be much richer in basic immunoglobulins gamma proteins (Ig-Gs) than that of pure lipid vesicles in the absence of DNA. According to the most recent evidences reported in the literature, this finding would suggest the existence of hybrid structures made of multilamellar complexes either stuck together by DNA or coexisting with DNA-loaded intact vesicles. Because surface properties of lipoplexes may determine their interaction with cells and tissues, these results may be important for predicting biological responses in vivo. © 2010 Elsevier B.V
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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