1,721,104 research outputs found
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
Glycobiology studies of influenza virus
Get PDFGlycans represent a class of macromolecules that exhibit vital biological roles in living organisms. They are not only essential for maintaining the normal functionalities of a cell, but are also involved in many pathogenic processes. The influenza A virus binds to glycan receptors that are expressed on the surface of respiratory epithelial cells of human airway and thereby initiates infection. Deciphering the structural features of glycans and comprehending their functional implications are thus crucial to expand our understandings of the disease. To validate the alternative models that are used in the studies of influenza, we generated the glycomic profiles from in vivo and in vitro experimental systems by mass spectrometry. A combination of MALDI-TOF MS, MALDI-TOF-TOF MS/MS, GC-EI-MS and enzymatic digestion experiments were utilised to characterise the structure of glycans.
The ferret has been used as an experimental animal to investigate the transmission and replication of influenza viruses. To verify the validity of this model, we carried out glycomic characterisation of ferret respiratory tissues to complement the data that was generated from human airway tissues. The mass spectrometric analysis indicates that the respiratory glycosylation of ferret highly resembles that of human, although distinctive expression of glycans displaying the Sda epitope are detected exclusively in ferret. Nonetheless, in comparison to other lab animals such as mouse and swine, ferret remains a better alternative model for studying the pathogenicity of influenza viruses. In the second project, we generated the glycomic profiles from human and ferret respiratory epithelial cells that were cultured under experimental conditions. Glycosylation patterns between these two in vitro systems are largely comparable, except the presence of the Sda epitope in ferret cells. However, when compared to their corresponding in vivo tissues, diminished structural repertoires especially the high-mass structures were observed.Open Acces
Characterisation of a unique epitope at the non-reducing end of the Brucella O-polysaccharide
Get PDFBrucellosis is a global zoonosis caused by the Gram negative bacteria Brucella. In animals the disease causes reproductive complications and in humans the disease causes debilitating illness. There is no vaccine for humans, wildlife or swine and the licensed vaccines for ruminants are protective but have disadvantages. The vaccines are live attenuated strains that can cause abortions in livestock. Humans can become infected by these vaccine strains. In animals the most protective vaccines contain O-polysaccharides (OPS) which induce antibodies that cannot be differentiated, by serodiagnostic tests, from antibodies raised during Brucella infection.
The O-polysaccharide (OPS) of Brucella species is an unbranched homopolymer of 4,6-dideoxy-4-formamido-α-D-mannopyranosyl residues (D-Rha4NFo). These residues are linked either by α1-2 or α1-3 glycosidic linkages. It is the sequence of these linkages that define the different epitopes of Brucella OPS. There are currently three described epitopes of the Brucella OPS that co-exist within the same OPS molecule; the A, M and C/Y epitopes. There is also a fourth epitope, the C epitope, which has not yet been formally agreed upon. The aim of this project was to determine whether the terminal D-Rha4NFo residues at the non-reducing end of the Brucella OPS form a previously undescribed series of tip epitope structures, defined by the necessity of inclusion of the terminal D-Rha4NFo to enable antibody binding.
The putative tip epitope was investigated by comparing antibody binding to whole cells, lipopolysaccharides (LPS), modified (so as to remove the tip) OPS and synthetic oligosaccharide-BSA antigens. The oligosaccharide-BSA antigens represent different epitopes and permit discrimination of different antibody populations. Results showed that terminal residues at the non-reducing end of the OPS bind antibodies and these antibodies are a separate anti-tip antibody population, different from the antibodies induced by the internal linear epitopes of the OPS.
Antibody binding studies showed that the in-tact terminal D-Rha4NFo is required for antibody binding to the tip epitope. Mice immunised with modified OPS-glycoconjugates, with linear epitopes and no tip epitope, raised anti-linear antibodies but did not raise anti-tip antibodies. These findings may show a pathway towards the generation of an OPS-glycoconjugate vaccine for brucellosis that permits differentiation of infected from vaccinated animals (DIVA) when paired with oligosaccharide-BSA diagnostic antigens containing the tip and M epitope. This is important for supporting livestock vaccination programmes to control brucellosis in order to reduce its impact upon human and animal health.Open Acces
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
Glycobiology studies of Influenza-A and SARS-CoV-2 respiratory viruses: the use of glycans as receptors and the role of host cells in viral protein glycosylation
No full textGlycosylation plays a significant role in the life cycle of many viruses: from providing a receptor
to assisting in the folding of viral proteins, as well as shielding these proteins from the host’s
immune system.
In the case of influenza A viruses, their surface glycoproteins haemagglutinin (HA) and
neuraminidase bind to glycans expressing sialic acid (Sia). In general, human IAVs prefer a2-
6 linked Sia, however, there are reports that H3N2 viruses are more selective in their HA
receptor preference: H3N2 viruses have evolved a preference for bi-antennary glycans
containing extended poly-LacNAc chains terminating in a2-6 linked Sia. This shift in receptor
preference has led to challenges propagating and characterising modern H3N2 viruses in the
laboratory. Here we demonstrate that targeting specific enzymes involved in glycosylation
pathways can produce extended glycan receptors in HEK cells, demonstrating the potential of
this approach to be applied to other cell lines.
Glycans have also been reported to act as secondary receptors enhancing infection of
the novel respiratory virus SARS-CoV-2. Multiple studies have highlighted the potential for
heparan sulfate (HS) to enhance SARS-CoV-2 cell entry. The mechanism by which SARS-
CoV-2 Spike binds to HS is poorly understood despite HS having been demonstrated to
enhance SARS-CoV-2 infection in vitro. We confirm that SARS-CoV-2 may utilize HS as a
potential secondary receptor and that both the receptor binding domain and N-terminal domain
of the Spike protein are likely to contribute to HS binding.
Finally, SARS-CoV-2 Spike itself is heavily glycosylated, however, there is variance
among the glycosylation profiles published to date, which provides increasing evidence that
the expression system used influences the glycosylation present on the Spike protein. We
have assessed the effect of using different expression systems to express SARS-CoV-2 spike
and find significant differences between glycosylation profiles depending on the expression
system used.Open Acces
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