1,720,998 research outputs found
Neural stem cells differentiated from human induced pluripotent stem cells (iPSCs) as a novel in vitro model to study developmental pathways in Huntington Disease
Full text linkHuntington Disease (HD) is an autosomal dominant disorder characterized by motor, cognitive and behavioral features caused by a CAG expansion in the HTT (huntingtin) gene beyond 35 repeats. Since the discovery of the HTT mutation 24 years ago, more than 15,000 papers have been published on HD. However, both the role of the huntingtin (wtHTT) in healthy individuals and the molecular mechanisms by which the mutated huntingtin causes the disease remain unclear. The discovery of induced pluripotent stem cell (iPSC) technology offer the possibility to generate patient-specific iPS cells and to enable the development of in vitro HD models that more accurately reflect the human disease. The disease-specific iPSCs can be differentiated into relevant cell-types affected in HD, holding a great potential for disease modeling and drug screening. In the present study, we have obtained dermal fibroblasts from 16 HD patients and 6 healthy controls. Fibroblasts from a young adult healthy control, a young subject with 43 CAG repeats, in an early stage of the disease and two JHD (Juvenile Huntington disease) patients were reprogrammed into induced pluripotent stem cells. All iPS clones that show an uniform flat morphology are characterized for their stemness and pluripotency, both in vitro through embryoid bodies formation and in vivo through teratoma formation assay. iPS cells from a JHD (85CAG) and healthy control, were differentiated into neurospheres of neural precursors (NPCs) by a new protocol optimized for differentiation of iPSCs derived embryoid bodies expressing all the three germ layers (ectoderm, mesoderm and endoderm) in neurospheres of Neural Stem Cells (NSCs). Differentiation assay confirmed that they possessed the potentiality, to differentiate into subtypes of neuronal and glial cells. Gene expression profiling was performed on iPSC HD-derived neurospheres using GeneChip Human Transcriptome Array 2.0. iPSC HD-derived neurospheres exhibit an impaired brain development processes when compared with iPSC-derived neurospheres from healthy individuals. This study aimed to produce a valid model of the Huntington disease. This novel in vitro model will permit us to have a closer view to neuronal development networks by morphologically and physiological studies on the cell types obtained from the neuropheres of NPC
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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