1,720,983 research outputs found
Combined treatment with three natural antioxidants enhances neuroprotection in a SH-SY5Y 3D culture model
Full text linkCurrently, the majority of cell-based studies on neurodegeneration are carried out on two-dimensional cultured cells that do not represent the cells residing in the complex microenvironment of the brain. Recent evidence has suggested that three-dimensional (3D) in vitro microenvironments may better model key features of brain tissues in order to study molecular mechanisms at the base of neurodegeneration. So far, no drugs have been discovered to prevent or halt the progression of neurodegenerative disorders. New therapeutic interventions can come from phytochemicals that have a broad spectrum of biological activities. On this basis, we evaluated the neuroprotective effect of three phytochemicals (sulforaphane, epigallocatechin gallate, and plumbagin) alone or in combination, focusing on their ability to counteract oxidative stress. The combined treatment was found to be more effective than the single treatments. In particular, the combined treatment increased cell viability and reduced glutathione (GSH) levels, upregulated antioxidant enzymes and insulin-degrading enzymes, and downregulated nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 1 and 2 in respect to peroxide-treated cells. Our data suggest that a combination of different phytochemicals could be more effective than a single compound in counteracting neurodegeneration, probably thanks to a pleiotropic mechanism of action
Are the Organoid Models an Invaluable Contribution to ZIKA Virus Research?
Full text linkAbstract: In order to prevent new pathogen outbreaks and avoid possible new global health threats, it
is important to study the mechanisms of microbial pathogenesis, screen new antiviral agents and test
new vaccines using the best methods. In the last decade, organoids have provided a groundbreaking
opportunity for modeling pathogen infections in human brains, including Zika virus (ZIKV) infection.
ZIKV is a member of the Flavivirus genus, and it is recognized as an emerging infectious agent
and a serious threat to global health. Organoids are 3D complex cellular models that offer an inscale organ that is physiologically alike to the original one, useful for exploring the mechanisms
behind pathogens infection; additionally, organoids integrate data generated in vitro with traditional
tools and often support those obtained in vivo with animal model. In this mini-review the value of
organoids for ZIKV research is examined and sustained by the most recent literature. Within a 3D
viewpoint, tissue engineered models are proposed as future biological systems to help in deciphering
pathogenic processes and evaluate preventive and therapeutic strategies against ZIKV. The next
steps in this field constitute a challenge that may protect people and future generations from severe
brain defect
The Application of TMD to Existing Buildings: the Idea and Future Developments
No full textThe aim of the proposed paper is the discussion of a strategy of seismic retrofitting which exploits the technique of the Tuned Mass Damper (TMD). The Tuned Mass Damper is an additional mass, usually located at the top of a building with the scope of reducing the seismic response. This technique is usually applied to tall buildings under dynamic actions manly due to wind. In the context of the built heritage, the idea is to realize an additional mass on the top of an existing building as a new storey or a portion of it, located on seismic isolators characterized by a fixed damping. This idea has already been applied successfully in Italy on some existing buildings
Advanced seismic retrofitting with high-mass-ratio Tuned Mass Dampers
No full textTuned Mass Dampers (TMDs) are traditionally employed in tall buildings to control displacements, typically featuring a low mass ratio. This study explores the potential of TMDs with significantly higher mass ratios for seismic retrofitting in existing civil structures, an area that remains largely unexplored. The research investigates non-conventional TMDs with exceptionally high mass ratios, which can be implemented by either elevating the existing structure or utilizing a part of the building's superstructure as a tuning mass on seismic isolators. A comprehensive parametric analysis was conducted, encompassing various ground motions, mass ratios, and damping levels, to refine the design of these TMD systems. The results, presented in detailed design charts, reveal optimal response characteristics based on the base structure's vibration period, TMD's damping, and additional mass. Notably, reductions in maximum top displacement of more than 30% and decreases in top acceleration of more than 40% were observed in certain configurations. The efficacy of these high mass ratio TMDs was further validated through a benchmark case study of an existing building, analyzed using non-linear Incremental Dynamic Analyses (IDAs). The findings indicate a significant enhancement in seismic performance and an improvement in structural response with the integration of non-conventional TMDs, suggesting a promising direction for seismic retrofitting in buildings designed under outdated seismic criteria
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
A GLANCE AT OPTIMAL CONFIGURATIONS OF LARGE MASS TUNED MASS DAMPERS IN SOIL-STRUCTURE SYSTEMS
No full textThe use of Tuned Mass Dampers featured by a Large Mass ratio (LM-TMDs) can represent an efficient solution for the seismic risk mitigation of structures, especially for seismic retrofitting of existing buildings in which a LM-TMD is conceived as a superelevation of the structural body. Although several studies in this field have dealt with optimization and technological developments, there is a lack of design criteria for LM-TMDs contemplating the influence of the soil-foundation interaction which can play a key role on the structural performance. Therefore, this study proposes a preliminary view to optimal configurations of LM-TMDs in soil-structure systems. To this end, a simplified interpretative model is used to carry out an extensive parametric analysis in the finite element framework OpenSees, considering a large variety of soil-structure layouts. Optimal solutions for the LM-TMD are identified, showing promising correlations between the non-dimensional quantities characterizing the LM-TMD and the soil-structure system
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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