1,720,984 research outputs found
Malaria vaccine: immunization of mice with a synthetic T cell helper epitope alone leads to protective immunity
No full textThe immunogenicity of the non-repetitive sequences of the Plasmodium berghei circumsporozoite (CS) protein was studied using synthetic peptides. Two CS sequences (residues 20-39 and 57-70) exhibiting T cell helper activity were identified. Immunization of BALB/c mice with a branched peptide containing either the 20-39 or the 57-70 sequence and two repeats (B epitope) in a linear sequence induced high titers of anti-repeat and anti-sporozoite antibodies. Mice immunized with the T-B construct (high antibody titers) or with the 57-70 epitope alone (no serum anti-repeat or anti-peptide antibodies) were protected to a similar degree after challenge with infective sporozoites. No protection was obtained in mice immunized with the 20-39 epitope. These results indicate that BALB/c mice can be protected either by effector T cells or by high levels of anti-repeat antibodies. Thus, in the same strain, a double mechanism of protection can be obtained by a synthetic peptide vaccine
Correlates of parasites and pseudoparasites in wolves (Canis lupus) across continents: A comparison among Yellowstone (USA), Abruzzo (IT) and Mercantour (FR) national parks
Full text linkLittle is known about the impact of infectious diseases on large carnivores. We investigated factors structuring the helminth and protozoan infections of wolves (Canis lupus) by using coprological analyses. Faecal samples (n = 342) were analysed from 11 wolf packs belonging to three different geographical and ecological settings in Italy (Abruzzo, Lazio e Molise National Park, PNALM: 4 packs, 88 samples), in France (Mercantour National Park, PNM: 4 packs, 68 samples) and in the U.S.A. (Yellowstone National Park, YNP: 3 packs, 186 samples). Parasites were found in 29.4%–88.6% of the samples and parasite taxa ranged from four to ten in each study area. Taeniidae (Taenia/Echinococcus), Sarcocystis spp. and Toxascaris leonina were most common in faecal samples from YNP, whereas Capillaria spp., Taeniidae and Uncinaria stenocephala were predominant in PNALM. We used generalised linear mixed models to assess the relationship between parasite infection or the number of parasite taxa and selected ecological drivers across study areas. Significant effects illustrated the importance of the ecological factors such as occurrence of free-ranging dogs, diet composition and wolf density, as well as the ancestry of the wolf populations, in shaping parasite-wolf communities. Additional investigations are needed to elucidate the impact of parasitic infections on wolf populations, as well as the role of anthropogenic factors in facilitating parasitic diffusion to apex predators
Plasmodium berghei subunit vaccine: repeat synthetic peptide of circumsporozoite protein comprising T- and B-cell epitopes fails to confer immunity.
No full textIn the murine malaria model induced by Plasmodium berghei, we studied the immunogenicity of the repeat region of the circumsporozoite (CS) protein, which is the main target of the antibody response in infected animals. We immunized several strains with a synthetic peptide--Y(DPPPPNPN)3--corresponding to one of the two P. berghei repeat sequences in complete Freund's adjuvant. Only C57BL/6 immune sera reacted with the synthetic peptide in ELISA and with the native CS protein on P. berghei sporozoites, as detected by immunofluorescence. From lymph node cells of immunized C57BL/6 we isolated two repeat-specific T-cell lines which proliferated in the presence of the synthetic peptide or the recombinant CS protein. We analysed the protective role of this repeat-specific response by injecting infectious sporozoites into mice immunized with irradiated sporozoites or with the repeat peptide. The percentage of mice developing parasitaemia was 80-90% in the peptide-immunized group and only 10-20% in the group immunized with irradiated sporozoites. Anti-repeat antibody titres were comparable in the two groups. On the basis of these results, we can conclude that the T- and B-cell response to the CS repeat obtained with this synthetic peptide immunization is not sufficient for a protective immunity
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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