1,721,092 research outputs found
Oxidative and nitrosative stress in the diaphragm of patients with COPD.
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51191.pdf (Publisher’s version ) (Open Access
Total Synthesis of the Zwitterionic Trisaccharide Repeating Unit of Fusobacterium nucleatum ATCC 51191 O-antigen
No full textHerein, we report an efficient total synthesis of Fusobacterium nucleatum ATCC 51191 zwitterionic trisaccharide repeating unit. Striking features of the target molecule are the presence of rare sugars, six nitrogen atoms dispersed over three sugars and functionalities like carboxylic acids and an amide. Challenges such as installation of 1,2-cis glycosidic linkage in AAT sugar, glycosylation using GlcNAcA donors with less reactive 4-OH of GlcNAcA, orthogonal late-stage amino acid coupling in the sterically hindered site, and synthesis of orthogonally protected rare amino sugars have been addressed. The total synthesis of target molecule accomplished via longest linear sequence of 22 steps in 2.3 % overall yield
Structure of the O-Antigen and the Lipid A from the Lipopolysaccharide of Fusobacterium nucleatum ATCC 51191
No full textFusobacterium nucleatum is a common member of the oral microbiota. However, this symbiont has been found to play an active role in disease development. As a Gram-negative bacterium, F. nucleatum has a protective outer membrane layer whose external leaflet is mainly composed of lipopolysaccharides (LPSs). LPSs play a crucial role in the interaction between bacteria and the host immune system. Here, we characterised the structure of the O-antigen and lipid A from F. nucleatum ssp. animalis ATCC 51191 by using a combination of GC-MS, MALDI and NMR techniques. The results revealed a novel repeat of the O-antigen structure of the LPS, [→4)-β-d-GlcpNAcA-(1→4)-β-d-GlcpNAc3NAlaA-(1→3)-α-d-FucpNAc4NR-(1→], (R=acetylated 60 %), and a bis-phosphorylated hexa-acylated lipid A moiety. Taken together these data showed that F. nucleatum ATCC 51191 has a distinct LPS which might differentially influence recognition by immune cells
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
Chemical Synthesis of the Trisaccharide Repeating Unit of the O‑Antigen of <i>Fusobacterium nucleatum</i> ATCC 51191
No full textHerein, the trisaccharide repeating unit of Fusobacterium
nucleatum ssp. animalis ATCC 51191, which
is used to develop oncomicrobial vaccines, was efficiently synthesized
for the first time. The synthetic approach featured the following:
(i) construction of the 1,2-cis-glycosidic linkage
using the large steric hindrance of a phthalimide group at C4 of fucosamine;
(ii) synthesis of the trisaccharide via a linear [2 + 1] glycosylation
strategy; and (iii) installation of l-alanine using hexafluorophosphate
azabenzotriazole tetramethyl uronium as a promoter
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
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