1,720,984 research outputs found
Liver regeneration in aged mice: new insights
Full text linkThe regenerative capacity of the liver after resection is reduced with aging. Recent studies on rodents revealed that both intracellular and extracellular factors are involved in the impairment of liver mass recovery during aging. Among the intracellular factors, age-dependent decrease of BubR1 (budding uninhibited by benzimidazole-related 1), YAP (Yes-associated protein) and SIRT1 (Sirtuin-1) have been associated to dampening of tissue reconstitution and inhibition of cell cycle genes following partial hepatectomy. Extracellular factors, such as age-dependent changes in hepatic stellate cells affect liver regeneration through inhibition of progenitor cells and reduction of liver perfusion. Furthermore, chronic release of pro-inflammatory proteins by senescent cells (SASP) affects cell proliferation suggesting that senescent cell clearance might improve tissue regeneration. Accordingly, young plasma restores liver regeneration in aged animals through autophagy re-establishment. This review will discuss how intracellular and extracellular factors cooperate to guarantee a proper liver regeneration and the possible causes of its impairment during aging. The possibility that an improvement of the liver regenerative capacity in elderly might be achieved through elimination of senescent cells via autophagy or by administration of direct mitogenic agents devoid of cytotoxicity will also be entertained
Molecular Targets of microRNAs during Liver Regeneration after Acute Injury: Recent Advances.
Full text linkExperimental models using 2/3 partial hepatectomy or chemical injury have helped identify the pathways associated with liver regeneration (LR). Several microRNAs (miRNAs) have been identified as modulators of LR, but the molecular mechanisms underlying their activity are still unclear. Given the development of new therapies targeting miRNAs, this is an important question to address. This review discusses recent studies exploring the molecular mechanisms of miRNA-dependent regulation of LR. In particular, the finding that circ-RBM23 promotes LR by sequestering cytoplasmic miRNA139-5p has furthered the understanding of the molecular mechanisms underlying circRNA activity. Interestingly, although miRNAs are generally considered negative regulators of their target mRNAs, miRNAs182-5p promotes LR by upregulating Cyp7a. Furthermore, mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) were shown to enhance LR after 2/3 partial hepatectomy by releasing miRNAs that inhibit gene expression to promote an anti-inflammatory response or miRNA-regulatory factors. Since the administration of MSCs-EVs has no hepatotoxic side effects, this may represent a therapeutic strategy to promote LR. miRNAs also mediate LR after chemical injury. This is the case for miR194 and miR21, whose downregulation activates pro-regeneration pathways to ameliorate acetaminophen-induced liver injury. In addition, the downregulation of miR21 has been shown to improve autophagy and haemostasis after acetaminophen overdose. Although further studies are needed to improve their efficacy as therapeutics, the evidence gathered in this review has led to a better understanding of the molecular mechanisms associated with the control of LR by miRNAs
Towards EEG-based Performance Assessment in Dataset Annotation Tasks
No full textArtificial intelligence is more and more adopted to complement human activity in solving complex tasks in several domains, including healthcare, security, finance, and automation. In order to be effective, several artificial intelligence tools rely on large training sets of carefully annotated data. Since labeling is mostly performed manually, it is a costly and error-prone process. Hence, there is increasing interest in devising innovative tools to support the annotation task. In this paper, we report an initial investigation on the application of EEG data mining for evaluating the performance of humans carrying out image annotation tasks. Our approach relies on a cheap portable EEG sensor and on supervised learning methods. We collected a dataset from five volunteers, and performed an initial evaluation of our technique. The achieved results are promising, and pave the way to several research directions. To the best of our knowledge, our work is the first one applying EEG data mining for assessing the performance of labelers
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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