1,721,325 research outputs found
Crystal Structure of I-Ak in Complex with a Dominant Epitope of Lysozyme
No full textAbstractWe have determined the structure of murine MHC class II I-Ak in complex with a naturally processed peptide from hen egg lysozyme (HEL residues 50–62) at 1.9 Å resolution. These results provide a structural basis for the I-Ak peptide-binding motif. Binding is established by the deep burial of five anchor side chains into specific pockets of the I-Ak binding groove, with a zen-like fit of an aspartic acid in the P1 pocket. We also show that in the I-Ak α chain, a bulge occurs in the first strand of the peptide-binding platform, an insertion probably common to all I-A and HLA-DQ alleles. The I-Ak β chain has a deletion in the helical region adjacent to the P7 pocket and an insertion in the helical region neighboring the P1 pocket. As a result of these structural features, the extended HEL peptide dips low into the center of the I-Ak groove and reaches toward solvent at its C-terminal end
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
A negatively charged anchor residue promotes high affinity binding to the MHC class II molecule I-Ak
No full textAn allele-specific peptide-binding motif for the murine MHC class II molecule I-Ak has proven elusive. Here we demonstrate that the I-Ak molecule preferentially binds peptides that contain negatively charged amino acids at the primary anchor position (Asp or Glu at P1), and that I-Ak can also bind peptides with polar residues at P1 (Cys, Ser, Asn, Gin, or Thr), although with lower affinity. This preference for a negatively charged anchor residue is so pronounced that polyalanine peptides containing a single Asp can bind to I-Ak. Eight naturally processed peptides were found to use an Asp, as demonstrated by a drop in the I-Ak binding affinity of these peptides after Ala substitution. The chemical identity of the amino acid in the anchor position was also important in determining the ability of peptide-I-Ak complexes to resist denaturation on SDS-polyacrylamide gels. The P1 binding pockets of HLA-DR and H-2E molecules are reported to be large and hydrophobic, and these class II molecules prefer to bind peptides with large aliphatic or aromatic side chains at P1. Our results suggest that the structure of the I-Ak P1 binding pocket is different. Based on sequence comparisons, we suggest that the P1 binding pockets of H-2A molecules may prove more polymorphic than the P1 binding pockets of H-2E molecules, and that this additional polymorphism will cause H-2A molecules to display larger intra-allelic differences in peptide binding specificities
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
List of <i>AK</i> genes in trypanosomatids.
No full text<p>* Here the original nomenclature [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0133676#pone.0133676.ref032" target="_blank">32</a>] was followed. These genes have been termed TbAK3 (AK1) and TbAK1 (AK3) by [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0133676#pone.0133676.ref014" target="_blank">14</a>].</p><p>List of <i>AK</i> genes in trypanosomatids.</p
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
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