1,721,076 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
Analysis of b cell responses to blood-stage malaria antigens in humans following immunization with candidate vaccines and controlled human malaria infection
Get PDFThe apicomplexan parasite Plasmodium falciparum is the causative agent of the most severe and deadly form of human malaria. The production of an efficacious malaria vaccine is seen as one of the key steps towards the eradication of the disease, however to date only one candidate has progressed to application for licensure. Candidate malaria vaccines target the different stages of the P. falciparum lifecycle through induction of a functional immune response. Vaccines targeting the blood-stage parasite require induction of high titre neutralising antibodies. To achieve this, vaccine regimens have been designed specifically to maximise antibody induction and maintenance in humans. The ultimate test of any candidate vaccine is clinical efficacy and controlled human malaria infection (CHMI) is a powerful tool for measuring this. This model can also be used to study how vaccine induced antigen-specific components of the immune system respond to native antigen exposure in the context of parasitic infection In this Thesis I describe the induction and maintenance of B cell responses, including memory B cells (mBC) and antibody secreting cells (ASC) to the candidate blood-stage malaria antigens MSP1 and AMA1 following vaccination with a variety of regimens and CHMI. These B cell populations along with peripheral blood T follicular helper (Tfh) cells correlate strongly with antibody induction. Within these populations I have identified a number of phenotypically distinct subsets which contribute to a functional response to vaccine and/or parasite antigen. From single cell sorting of ASC at day seven post-boost I have managed to produce the first fully human monoclonal antibodies (hmAbs) specific for AMA1, one of which shows significant growth inhibitory activity (GIA). Despite promise the vaccine candidates MSP1 and AMA1 have been disappointing in terms of human efficacy. In this Thesis I have attempted to provide explanations on a cellular level as to why there is such disparity between pre-clinical and human data and ultimately why these candidates may have failed to provide efficacy. Such work will provide a strong basis for analysing future clinical trials of alternative candidate blood-stage vaccines and allow accurate characterisation of immune correlates and clinical efficacy when it is achieved
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
Enhancing the efficacy of viral vector blood-stage malaria vaccines
Get PDFReplication-deficient adenovirus (Ad) and modified vaccinia virus Ankara (MVA) vectors expressing single Plasmodium falciparum antigens can induce potent T cell and antibody responses and have entered clinical testing using a heterologous prime-boost immunisation approach (Ad_MVA). This thesis describes a number of pre-clinical approaches aimed at enhancing the efficacy of these viral vectored vaccines targeting the blood-stage of malaria. First, the development of a highly efficacious malaria vaccine is likely to require a multi-antigen and/or multi-stage subunit vaccine. The utility of an Ad_MVA immunisation regime combining vaccines expressing the 42kDa C-terminus of the blood- stage antigen merozoite surface protein 1 (MSP142) and the pre-erythrocytic antigen circumsporozoite protein (CSP) in the P. yoelii mouse model was investigated. It was found that vaccine co- administration leads to maintained antibody responses and efficacy against blood-stage infection, but reduced secondary CD8+ T cell responses and efficacy against liver-stage infection. CD8+ T cell interference can be minimised by co-administering the MVA vaccines at separate sites, resulting in enhanced liver-stage efficacy. The mechanisms of CD8+ T cell interference were explored. Second, Ad_MVA regimes expressing blood-stage antigens that can protect against P. chabaudi and P. yoelii blood-stage infection were tested against P. berghei, but did not confer protection. Similarly, IgG from rabbits immunised against P. falciparum MSP1 (PfMSP1) could not protect mice from a chimeric P. berghei parasite expressing PfMSP1. Third, two molecular adjuvants, the C4bp α-chain oligomerisation domain (IMX108/313) and the Fc fragment of murine IgG2a, were tested for their ability to enhance immunogenicity of recombinant adenoviruses when fused at the C-terminus of a blood-stage antigen. IMX108/313 was found to adjuvant T cell responses of small (< 80kDa) antigens and this was associated with antigen oligomerisation. However, the Fc fragment did not adjuvant responses. Finally, it was found that using a strong early promoter to drive antigen expression enhances the immunogenicity of single administration MVA vaccines, but that this did not enhance post-boost immunogenicity in an Ad_MVA regime
New approaches for improving the immunogenicity of modified vaccinia virus Ankara as a recombinant vaccine vector
Get PDFThe CD8+ T cell response to a transgenic antigen expressed in Modified Vaccinia virus Ankara (MVA) can be augmented with enhanced transgene expression. This thesis presents different approaches to increase transgene expression in MVA. The transgene used was the sequence of the pb9 murine malaria epitope, fused to Renilla luciferase gene, and then fused to a secretion leader sequence (tPA) at the N terminus. The insertion of Internal Ribosomal Entry Site (IRES) upstream of the transgene, driven by the pB8 promoter and inserted at the B8R locus, or the modification of the pB8 promoter by nucleotide substitution both failed to enhance the transgene expression or immunogenicity. However, utilising endogenous promoters such as the pB8, pE3, and pF11 at their natural loci to drive the transgene resulted in lower transgene expression in vitro, but stronger immune responses to the pb9 epitope in BALB/c mice, as compared to the conventional p7.5 or mH5 promoters. Utilising these promoters at the TK locus (ectopic promoters) revealed similar patterns of transgene expression and immunogenicity, indicating that the improved immunogenicity is linked to promoters despite the low transgene expression measured in vitro. Therefore, the pF11 promoter was further studied to determine its activity in vivo and showed higher transgene expression, as compared to the mH5, which correlated with in vivo immunogenicity. Inactivation of the TK gene in MVAs with endogenous promoters showed reduced in vivo transgene expression and immunogenicity. Finally, in a related attempt to enhance MVA immunogenicity, deleting multiple immunomodulatory genes from the MVA genome did not affect MVA cellular immunogenicity in a range of vaccination regimens, testing either the pb9 epitope or the M. tuberculosis antigen 85A
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