Redes sociales en Iberoamérica. Artículo de revisión

This paper presents an analysis of the existing literature on social networks in Ibero-America, with the objective of organizing the main topics covered, highlighting findings, and proposing future research paths. The four thematic areas that stand out are political communication and electronic government; journalism and traditional media; social groups (including adolescents and young people, those marginalized, women, entrepreneurs and influencers, students, and older adults) and areas of use (including commerce, tourism, education, health, professional communication); and political and civic participation. In addition, we review the literature from the perspective of the platforms (Twitter, Facebook, WhatsApp, Instagram, YouTube, and Snapchat) and from the geographical regions and countries that make up Ibero-America, to observe similarities and differences. We conclude with the mention and analysis of the two most outstanding patterns of the studies examined: 1) a tendency to expect from the networks a transformative potential that is not necessarily proven, especially in the case of political communication and journalism; 2) transformative capacity of networks in the areas of tourism, education and health, in which traditional media have not been characterized by having a prominent role. Finally, we propose some paths for future studies, among them the pursuit of comparative works, the incorporation of relational perspectives in the treatment of networks, the addition of mixed, experimental and computational methodologies, and the consideration, from the research design standpoint, of the acceleration of technological change and the need to generate questions and conceptualizations capable of surviving the passage of time

Redes sociales en Iberoamérica. Artículo de revisión

This paper presents an analysis of the existing literature on social networks in Ibero-America, with the objective of organizing the main topics covered, highlighting findings, and proposing future research paths. The four thematic areas that stand out are political communication and electronic government; journalism and traditional media; social groups (including adolescents and young people, those marginalized, women, entrepreneurs and influencers, students, and older adults) and areas of use (including commerce, tourism, education, health, professional communication); and political and civic participation. In addition, we review the literature from the perspective of the platforms (Twitter, Facebook, WhatsApp, Instagram, YouTube, and Snapchat) and from the geographical regions and countries that make up Ibero-America, to observe similarities and differences. We conclude with the mention and analysis of the two most outstanding patterns of the studies examined: 1) a tendency to expect from the networks a transformative potential that is not necessarily proven, especially in the case of political communication and journalism; 2) transformative capacity of networks in the areas of tourism, education and health, in which traditional media have not been characterized by having a prominent role. Finally, we propose some paths for future studies, among them the pursuit of comparative works, the incorporation of relational perspectives in the treatment of networks, the addition of mixed, experimental and computational methodologies, and the consideration, from the research design standpoint, of the acceleration of technological change and the need to generate questions and conceptualizations capable of surviving the passage of time

Oxidative stress targets in pulmonary emphysema: focus on the Nrf2 pathway

IMPORTANCE OF THE FIELD: Oxidative stress has been implicated in the pathogenesis of pulmonary emphysema. Nuclear factor erythroid-2-related factor 2 (Nrf2) a major antioxidant transcription factor could play a protective role in pulmonary emphysema. AREAS COVERED IN THIS REVIEW: Nrf2 is ubiquitously expressed throughout the lung, but is predominantly found in epithelium and alveolar macrophages. Evidence suggests that Nrf2 and several Nrf2 downstream genes have an essential protective role in the lung against oxidative stress from environmental pollutants and toxicants such as cigarette smoke, a major causative factor for the development and progression of pulmonary emphysema. Application of Nrf2-deficient mice identified an extensive range of protective roles for Nrf2 against the pathogenesis of pulmonary emphysema. Therefore, Nrf2 promises to be an attractive therapeutic target for intervention and prevention strategies. WHAT THE READER WILL GAIN: In this review, we discuss recent findings on the association of oxidative stress with pulmonary emphysema. We also address the mechanisms of Nrf2 lung protection against oxidative stress based on emerging evidence from experimental oxidative disease models and human studie. TAKE HOME MESSAGE: The current literature suggests that among oxidative stress targets, Nrf2 is a valuable therapeutic target in pulmonary emphysema

Coating carbon nanotubes with a polystyrene-based polymer protects against pulmonary toxicity

BACKGROUND: carbon nanotubes (CNT) can have adverse effects on health. Therefore, minimizing the risk associated with CNT exposure is of crucial importance. The aim of this work was to evaluate if coating multi-walled CNT (MWCNT) with polymers could modify their toxicity, thus representing a useful strategy to decrease adverse health effects of CNT. We used industrially-produced MWCNT uncoated (NT1) or coated (50/50 wt%) with acid-based (NT2) or polystyrene-based (NT3) polymer, and exposed murine macrophages (RAW 264.7 cell line) or Balb/c mice by intratracheal administration. Biological experiments were performed both in vitro and in vivo, examining time- and dose-dependent effects of CNT, in terms of cytotoxicity, expression of genes and proteins related to oxidative stress, inflammation and tissue remodeling, cell and lung tissue morphology (optical and transmission electron microscopy), and bronchoalveolar lavage fluid content analysis.RESULTS: extensive physico-chemical characterization of MWCNT was performed, and showed, although similar dimensions for the 3 MWCNT, a much smaller specific surface area for NT2 and NT3 as compared to NT1 (54.1, 34 and 227.54 m(2)/g respectively), along with different surface characteristics. MWCNT-induced cytotoxicity, oxidative stress, and inflammation were increased by acid-based and decreased by polystyrene-based polymer coating both in vitro in murine macrophages and in vivo in lung of mice monitored for 6 months.CONCLUSIONS: these results demonstrate that coating CNT with polymers, without affecting their intrinsic structure, may constitute a useful strategy for decreasing CNT toxicity, and may hold promise for improving occupational safety and that of general the user

Preconcentration techniques for trace analysis via neutron activation

A review is given of the methods that have been proposed for enrichment of trace elements in samples that are to be analysed by neutron-activation methods. The emphasis is on classification of methods, with full illustrations by means of practical examples.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34169/1/0000457.pd

The policy gives to speak: Engagement in social networks of news sites

This paper analyses the relationship between the contents presented in the official Facebook and Twitter accounts of eight news sites in Argentina and the level of engagement they generate among users. The analysis of a sample of 2,039 news items, published between the months of March to November 2017, shows that there is a correlation between the content of the news and the level of engagement that they create among users. Although the sites presented a greater amount of news on issues of non-public issues, such as sports, police or entertainment, the highest levels of engagement were recorded in news on public issues, such as national and international policy and economy. These findings are consistent with the literature on the process of adaptation of the media to the new media ecosystem and support the theory of “monitorial citizenship” in the digital context

Política y pelotas: los intereses temáticos de los usuarios de sitios de noticias líderes en Argentina en 2016

Este trabajo examina las preferencias temáticas de los consumidores de noticias online en la Argentina durante 2016, a través de un método mixto que integra análisis de contenido con entrevistas en profundidad. El análisis cuantitativo, realizado en siete de los sitios de noticias más importantes de la Argentina, indica que durante el año 2016 las noticias sobre política y deportes fueron las más vistas, aunque este interés no fue constante: las notas sobre el gobierno del presidente Mauricio Macri y las denuncias por casos de corrupción tuvieron una posición dominante entre las más leídas durante el primer semestre, mientras que en la segunda parte del año dicha posición fue ocupada por noticias sobre los logros de los deportistas. La violencia de género, un tema de incipiente importancia en la agenda pública, ocupó en promedio solo el 4% de las noticias más vistas, aunque los datos muestran picos de interés durante los momentos de mayor movilización sobre esta problemática. Las entrevistas en profundidad sugieren que las audiencias se informan sobre temas de política para cumplir un rol ciudadano; esta práctica informativa suele estar asociada con emociones negativas como frustración, enojo y angustia. Por el contrario, el consumo de información deportiva se realiza con objetivos de esparcimiento, y tiene una carga emocional positiva vinculada con la identificación con los atletas y la diversión

Altered Nrf2/Keap1-Bach1 equilibrium in pulmonary emphysema

BACKGROUND: Oxidative stress, resulting from the increased oxidative burden and decreased level of antioxidant proteins, plays a role in the pathophysiology of smoking-related pulmonary emphysema. Expression of several antioxidant proteins, such as heme oxygenase-1 (HO-1), glutathione peroxidase 2 (GPX2) and NAD(P)H:quinone oxidoreductase 1 (NQO1), results from an equilibrium created by positive or negative regulation by the transcription factors Nrf2, Keap1 and Bach1, respectively. However, whether the expression of these transcription factors is altered in emphysema and could account for decreased expression of antioxidant proteins is not known. A study was undertaken to investigate the expression and subcellular localisation of Nrf2, Keap1 and Bach1 as potential regulators of HO-1, GPX2 and NQO1 in alveolar macrophages, a key cell in oxidative stress, in lung surgical specimens from non-smokers without emphysema and smokers with and without emphysema. METHODS AND RESULTS: Western blot, immunohistochemical and laser scanning confocal analysis revealed that the Nrf2 protein level decreased significantly in whole lung tissue and alveolar macrophages (cytosol and nucleus) in patients with emphysema compared with those without emphysema. Conversely, Bach1 and Keap1 levels were increased in patients with emphysema. These modifications were associated with a parallel decrease in the expression of HO-1, GPX2 and NQO1 at the cellular level, which was inversely correlated with airway obstruction and distension indexes, and increased macrophage expression of the lipid peroxidation product 4-hydroxy-2-nonenal. Silencing RNA experiments in vitro in THP-1 cells were performed to confirm the cause-effect relation between the loss of Nrf2 and the decrease in HO-1, NQO1 and GPX2 expression. Nrf2/Keap1-Bach1 equilibrium was altered in alveolar macrophages in pulmonary emphysema, which points to a decreased stress response phenotype. CONCLUSIONS: This finding opens a new view of the pathophysiology of emphysema and could provide the basis for new therapeutic approaches based on preservation and/or restoration of such equilibrium