1,721,073 research outputs found
MicroRNAs role in type 1 diabetes pathogenesis: a dialogue between pancreatic islets and immune system
No full textType 1 diabetes (T1D) is a chronic multifactorial autoimmune disease that includes 5-10% of diabetes cases and is characterized by the immune-mediated insulin secreting β cell destruction with consequent loss of β cell mass and hyperglycemia. In autoimmune diabetes, the selective β cell destruction is the result of a series of mechanisms including, but not limiting to autoreactive T cells direct β cell destruction and inflammatory stress, resulting in a dramatic loss of functional β cell mass.
MicroRNAs are small non coding 19-24 nucleotides RNAs that negatively regulate gene expression, binding selectively their mRNAs target and leading to their translational repression and/or degradation. It was also remarked that miRNAs are involved in T1D pathogenesis, by regulating a series of processes both in β cells and lymphocytes that ranged from cell metabolic dysfunction and apoptosis to dedifferentiation and immune molecule secretion. Additionally, it has been suggested that secreted microRNAs can take part in the communication between immune system and pancreatic endocrine cells; therefore, studying such dialogue could help to better understand T1D pathogenesis and to the identification of biomarkers that reflect the diseased status of the target organ.
In order to investigate the role of miRNAs as biomarkers of T1D pathogenesis both at endocrine and immune interface, the study can be subdivided into the following sections:
1) MiRNAs as circulating biomarkers of diseased-target tissue- In this section, miR-409-3p was found downregulated in murine and human plasma of T1D subjects, highlight the importance to find a lymphocyte deriving circulating biomarker that reflect the target organ pathological status.
2) MiRNAs as modulators of β cell function- miR-183-5p was downregulated in pancreatic endocrine tissue of mouse and human diabetic patients, contributing to β cell protection from apoptosis through the modulation of anti-apoptotic factor Bach2 and through the potential induction of a dedifferentiation phenomenon. This study demonstrated that β cells are able to react to stress and to cell damage through a miRNA-mediated protective phenomenon.
3) Secreted/Immune-derived miRNAs as mediators of β cell apoptosis- Exosomes enriched in miR-142-3p/5p and miR-155 and secreted by T autoreactive lymphocytes, induced selective β cell apoptosis, through the modulation of proinflammatory chemokine expression. The selective AAV “Sponge” inactivation of miR-142-3p/5p, miR-150 and miR-155 induced β cell protection of prediabetic NOD mice from the autoimmune attack that occurs in T1D, inducing the reduction of the proinflammatory chemokine CXCL10 specifically in β cells than in α cells. Such study remarked the exosome-mediated communication dynamics between immune system components and endocrine cells in the center of this dialogue, miRNAs give their fundamental contribution and more importantly, as it has already been reported, it’s possible to actively and therapeutically interfere in this dialogue in order to positively change the β cell fate
Abelian link invariants and homology
No full textWe consider the link invariants defined by the quantum Chern-Simons field theory with compact gauge group U(1) in a closed oriented 3-manifold M. The relation of the Abelian link invariants with the homology group of the complement of the links is discussed. We prove that, when M is a homology sphere or when a link in a generic manifold M is homologically trivial, the associated observables coincide with the observables of the sphere S(3). Finally, we show that the U(1) Reshetikhin-Turaev surgery invariant of the manifold M is not a function of the homology group only, nor a function of the homotopy type of M alone. (C) 2010 American Institute of Physics. [doi:10.1063/1.3431031
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
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