1,721,051 research outputs found
Strategies to Counteract Oxidative Stress and Inflammation in Chronic-Degenerative Diseases
Full text linkThe great increase in life expectancy is linked to the necessity of counteracting chronic-degenerative diseases, e [...
Strategies to Counteract Oxidative Stress and Inflammation in Chronic-Degenerative Diseases 2.0
Full text link: Oxidative stress and inflammation are recognized as pivotal contributors and common features of several chronic degenerative diseases, including cancer, metabolic syndrome, type 2 diabetes, cardiovascular diseases and neurodegenerative disorders, affecting a high percentage of the population [...]
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
Combination of Epigallocatechin Gallate and Sulforaphane Counteracts In Vitro Oxidative Stress and Delays Stemness Loss of Amniotic Fluid Stem Cells
Full text linkAmniotic fluid stem cells (AFSCs) are characterized in vivo by a unique niche guarantying their homeostatic role in the body. Maintaining the functionality of stem cells ex vivo for clinical applications requires a continuous improvement of cell culture conditions. Cellular redox status plays an important role in stem cell biology as long as reactive oxygen species (ROS) concentration is finely regulated and their adverse effects are excluded. The aim of this study was to investigate the protective effect of two antioxidants, sulforaphane (SF) and epigallocatechin gallate (EGCG), against in vitro oxidative stress due to hyperoxia and freeze-thawing cycles in AFSCs. Human AFSCs were isolated and characterized from healthy subjects. Assays of metabolic function and antioxidant activity were performed to investigate the effect of SF and EGCG cotreatment on AFSCs. Real-time PCR was used to investigate the effect of the cotreatment on pluripotency, senescence, osteogenic and adipogenic markers, and antioxidant enzymes. Alkaline phosphatase assays and Alizarin Red staining were used to confirm osteogenic differentiation. The cotreatment with SF and EGCG was effective in reducing ROS production, increasing GSH levels, and enhancing the endogenous antioxidant defences through the upregulation of glutathione reductase, NAD(P)H:quinone oxidoreductase-1, and thioredoxin reductase. Intriguingly, the cotreatment sustained the stemness state by upregulating pluripotency markers such as OCT4 and NANOG. Moreover, the cotreatment influenced senescence-associated gene markers in respect to untreated cells. The cotreatment upregulated osteogenic gene markers and promoted osteogenic differentiation in vitro. SF and EGCG can be used in combination in AFSC culture as a strategy to preserve stem cell functionality
Dietary Phenolic Acids Act as Effective Antioxidants in Membrane Models and in Cultured Cells, Exhibiting Proapoptotic Effects in Leukaemia Cells
Full text linkCaffeic, syringic, and protocatechuic acids are phenolic acids derived directly from food intake or come from the gut metabolism of polyphenols. In this study, the antioxidant activity of these compounds was at first evaluated in membrane models, where caffeic acid behaved as a very effective chain-breaking antioxidant, whereas syringic and protocatechuic acids were only retardants of lipid peroxidation. However, all three compounds acted as good scavengers of reactive species in cultured cells subjected to exogenous oxidative stress produced by low level of H2O2. Many tumour cells are characterised by increased ROS levels compared with their noncancerous counterparts. Therefore, we investigated whether phenolic acids, at low concentrations, comparable to those present in human plasma, were able to decrease basal reactive species. Results show that phenolic acids reduced ROS in a leukaemia cell line (HEL), whereas no effect was observed in normal cells, such as HUVEC. The compounds exhibited no toxicity to normal cells while they decreased proliferation in leukaemia cells, inducing apoptosis. In the debate on optimal ROS-manipulating strategies in cancer therapy, our work in leukaemia cells supports the antioxidant ROS-depleting approach
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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