1,720,959 research outputs found
Carbon Nanotube Membranes in Water Treatment Applications
Full text linkCarbon nanotube (CNT)-based membranes combine the promising properties of CNTs with the advantages of membrane separation technologies, offering enhanced membrane performance in terms of permeability and selectivity. This review looks at the existing membrane architectures based on CNTs and their main advantages and disadvantages for water treatment applications. The different types of CNT-based membranes that are reported in the literature are highlighted, as well as their corresponding fabrication methods. Available methodologies for tailoring the final membrane properties and behavior are thoroughly discussed, making special emphasis in chemical modification of the CNT surface. Finally, the most common applications of CNT-based membranes in water treatment are reviewed, including seawater or brine desalination, oil-water separation, removal of heavy metals, and organic pollutants. The main limitations and perspectives of CNT-based membranes are also briefly outlined
Carbon nanotubes for cardiac tissue regeneration: State of the art and perspectives
Full text linkCarbon nanotubes (CNTs) have appeared in recent years as innovative components for the development of the next-generation scaffolds to regenerate damaged cardiac tissue. The unique robustness, mechanical and electronic properties of CNTs, along with their ease to undergo chemical modification, make them promising candidates for the design of engineered cardiac constructs with ad hoc properties. The integration of CNTs with polymeric scaffolds is a promising strategy for cardiac regeneration since, as reviewed in these pages, their conductivity has a boosting effect on cardiomyocytes behavior, including their synchronous contractility when grown on top of the nanomaterial. More recently, the conductive properties of pure CNTs are attracting interest to design innovative systems based on bare CNTs without using other fillers. Additionally, the elongated CNT morphology is a strategic asset for the mimicry of the anisotropic myocardium structure, and research has made great progress over the production of micropatterned scaffolds with nanoscale definition that aim to recapitulate the cardiac tissue. Overall, engineered CNT constructs are revealing their great potential to develop new platforms able to interface, repair, or boost the performance of cardiac tissue
Carbon Nanostructures in Rotaxane Architectures
No full textMechanically interlocked molecular architectures equipped with different types of carbon nanostructures have been a topic of high interest in the last decades. This minireview reports the research work published in the literature and the main advances that have been realized in rotaxane architectures involving fullerenes and carbon nanotubes
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
Chemically Cross-Linked Carbon Nanotube Films Engineered to Control Neuronal Signaling
Full text linkIn recent years, the use of free-standing carbon nanotube (CNT) films for neural tissue-engineering have attracted tremendous attention. CNT films show large surface area and high electrical conductivity that combined to flexibility and biocompatibility may promote neuron growth and differentiation while stimulating neural activity. Besides, adhesion, survival, and growth of neurons can be modulated through chemical modification of CNTs. Axonal and synaptic signaling can also be positively tuned by these materials. Here we describe the ability of free-standing CNT films to influence neuronal activity. We demonstrate that the degree of crosslinking between the CNTs has a strong impact on the electrical conductivity of the substrate, which, in turn, regulates neural circuit outputs
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