1,720,959 research outputs found
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
Functional and biochemical characterization of Nod2 and Hsp70, important proteins involved in Crohn's disease
No full textGrimes, Catherine LeimkuhlerMicrobes are detected by specific host pattern recognition receptors (PRR) through the pathogen-associated molecular patterns (PAMPs). Nucleotide binding oligomerization domain-containing protein 2 (Nod2) is an intracellular PRR that recognizes fragments of bacterial cell wall. Nod2 is important to human biology, as when it is mutated it loses the ability to respond properly to bacterial cell wall fragments and subsequently mutations in Nod2 correlated to the development of a number of human diseases, including Crohn’s disease. In order to determine the mechanisms of misactivation in the Nod2 Crohn’s associated Nod2 mutants, we developed a cell based system to screen for protein-protein interactors of Nod2. We identified heat shock protein 70 (Hsp70) as a protein interactor of both wild-type and Crohn’s associated Nod2 mutations. Hsp70 is a highly ubiquitous protein that is responsible for stabilizing many proteins within the cell. Recently, Hsp70 has been linked with inflammation, especially in the regulation of anti-inflammatory molecules. This thesis uses a combination of molecular cellular biology and biochemistry to dissect the role of Hsp70 in Nod2 signaling. ☐ The preliminary identification of the Hsp70:Nod2 interaction was confirmed using a series of co-immunoprecipitation experiments in which the domains of Hsp70 and Nod2 that are necessary and sufficient for the interaction were identified. We identified that the nucleotide binding domain (NBD) and the leucine rich repeat (LRR) domain of Nod2 interact with Hsp70, whereas the substrate binding domain (SBD) of Hsp70 interacts with Nod2. ☐ Limited proteolysis experiments were performed to probe if the mechanism of Hsp70 stabilization of Nod2 was dependent of the ATPase activity of Hsp70. For these experiments, a mutant of Hsp70 that is capable of binding to ADP but not ATP was utilized. Our data suggest that the ATPase activity is dispensable for Nod2 stabilization. Additional biochemical experiments imply that a co-chaperone, Hsp40, plays a role in the Nod2-Hsp70 interaction. Thus, these biochemical studies have identified that interaction of Hsp70-Hsp40 with Nod2 is sufficient for stabilization. ☐ In order to determine the effect of Hsp70 in cells on Nod2 signaling, a series of experiments were performed in which the levels of Hsp70 was modulated. If the levels of Hsp70 were increased, Nod2’s cellular response to bacterial cell wall fragments increased. Alternatively, if Hsp70 levels were decreased, using a Hsp70 inhibitor, KNK437, Nod2 mediated NF-κB activation in response to bacterial cell wall stimulation decreased. We found Hsp70 to regulate Nod2’s half-life, as increasing the Hsp70 level in cells increased Nod2’s half-life, and down-regulating Hsp70 decreased Nod2’s half-life. ☐ The Hsp70:Nod2 interaction also was present with the Crohn’s associated Nod2 variants. We found that the expression level of the Crohn’s associated Nod2 variants was lower compared to that of wild-type. Overexpression of Hsp70 significantly increased Nod2 levels as well as the signaling capacity of the mutants; thus, our study shows that restoring the stability of the Nod2 Crohn’s mutants is sufficient for rescuing the ability of these mutations to signal in the presence of a bacterial cell wall ligand. Thus, by identifying Hsp70 as a Nod2 interactor, this thesis has: (1) allowed for the development of two Nod2 stabilization assays (in vitro proteolysis and cellular half-life) to be developed, (2) accelerated the endogenous expression and purification of both wild type and Crohn’s associated Nod2 mutants and (3) identified a novel mechanism, stabilization of Nod2, to treat Crohn’s disease.University of Delaware, Department of Biological SciencesPh.D
Role of L1-FGFR interaction in glioma progression
No full textThe L1CAM cell adhesion/recognition molecule (L1CAM, CD171) and Fibroblast Growth Factor Receptor (FGFR) are expressed by human high-grade glioma cells. L1CAM is a cell adhesion molecule that has homophilic interactions as well as heterophilic interactions with FGFR and integrins. Our lab previously showed that L1CAM cleavage is associated with an increased rate of migration of glioma cells and this correlates with increased focal adhesion kinase (FAK) activation. FGFR activation via its canonical FGF ligand leads to the transmission of intercellular signals responsible for cell proliferation, migration and survival. It has been observed that FGFR1 is expressed in glioma tissues, but is absent in the normal surrounding brain tissue. Analyzing datasets from a wide range of clinical samples showed that FGFR1 is over expressed in glioma samples regardless of its grade, while there is a gradual increase in the expression level of ADAM10 with the progression of glioma to various grades. In this study I used short hairpin RNA (shRNA) and dominant-negative approaches to inhibit the expression and activation of L1CAM and FGFR1, respectively. An L1-CHD peptide that inhibits L1-FGFR interaction and PD173074, a chemical inhibitor of FGFR1, also were used to elucidate the involvement of L1-
FGFR interactions on glioma cell behavior. Migration studies and cell cycle analyses showed the relevance in the contribution of L1CAM towards FGFR activation. Also. L1CAM interaction with FGFR had no effect on cell proliferation on subconfluent cultures, while blocking L1-FGFR on confluent glioma cell decreased the S phase to 43% compared to the untreated. It was also observed that L1CAM attenuated cells exhibited almost the same amount of reduction in migration as in cells deprived of FGFR signaling. While specifically blocking L1-FGFR interaction there was a decrease of 50% in migration rate in T98G cells compared to the control cells, and there was a decrease in 24% in U-118/L1LE cells compared to the control cells. This study showed that treatment of glioma cells through FGFR inactivation by targeting only its native FGF ligand might be ineffective due to a major contribution of the receptor activation through L1CAM. Both L1CAM and FGFR1 shutdown glioma cells exhibited a complete termination of cell migration in vitro. These results indicate that L1CAM modulates motility and proliferation of human glioma cells via signaling through the FGFR. This could justify the relevance of targeting a cell adhesion molecule as well as a robust receptor in the treatment of malignant gliomas by disrupting cell invasion and growth.Galileo, Deni S.M.S.University of Delaware, Department of Biological Science
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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