1,720,960 research outputs found
In vitro toxicity of new engineered nanoparticles through their life cycle
Full text linkThe rapid development of nanotechnology has caused concerns about
nanoproducts on human health throughout their lifecycle. As part of the consortium
NEPHH (nanomaterial related environmental pollution on human health through their
life cycle, funded by EU-FP7), this project aimed to assess the potential effect of novel
polymer-silicon composites on human health from a lifecycle perspective, focusing on
in vitro toxicity of raw silica nanoparticles (SiNP) and dust nanoparticles (NP) released
from silicon-based polymer composites. The main objectives were to characterise a
group of amorphous SiNP and dust NP in water and cell culture medium; assess NP
toxicity potential in in vitro models; and establish mode of SiNP action.
The selection of SiNP of size 7-14 nm was based on their wide use in
developing polymer nanocomposites. Dust NP were generated from mechanical
processing of polymer composites made of polyamide-6 (PA6), polyurethane (PU) and
polypropylene (PP), each incorporated with SiNP or 3 other different silicon
reinforcement materials. The dispersion and size of NP in water and in cell culture
medium were characterized using dynamic light scattering, scanning electron
microscopy and transmission electron microscopy. The chemical composition of NP
was assessed by infra-red spectroscopy. NP were assessed in vitro for induction of
membrane damage, intracellular reactive oxygen species (ROS), loss of cell viability,
and cellular uptake by flow cytometry and confocal microscopy. In order to identify
potential biomarkers for toxicity prediction, miRNA array and extracellular
metabonomic assays were performed.
The size of SiNP (10-100 µg/ml) ranged from ~200-500 nm in water and ~20-
500 nm in culture medium, indicating the presence of aggregates. The infra-red
spectrum of SiNP dried from culture medium showed a slight difference as compared
with that dried from water, indicating protein adsorption. SiNP induced acute ROS
increase, cell membrane damage, and reduction in cell viability after 48 h in human lung
carcinoma epithelial A549 cells, lung fibroblast MRC-5 cells and skin HaCaT
keratinocytes. SiNP were up taken by all 3 cell types, and located in the cytosol. Six
early (<48h) SiNP responsive miRNAs were identified in A549 cells. SiNP also induced early changes in metabolites including glucose, lactate, ethanol, phenylalanine, histidine
and tyrosine. Dust NP generated from PA6 group materials were more toxic than those
from other polymer composites when assessed at 25-100 µg/ml at 72 h in A549 cells.
The results obtained from this study suggest that 1) both small and larger SiNP
aggregates are taken up into the target cells; 2) conventional cytotoxicity assays
combined with miRNA and metabonomic assays provide insight into the molecular
mechanisms of the nanotoxicity; 3) metabonomics and miRNA assays can serve as
robust tools for recognising sub-toxic dose-effect relationships; 4) the toxicity of dust
NP from polymer composites depends on polymer type but not reinforcement materials.
This study demonstrated the importance of lifecycle analysis as opposed to single stage
analysis of novel materials. Further studies need to improve study design to enable
interpretation of cytotoxicity in relation to NP size, physiochemical property and
intracellular dose, and to simulate the health effect of polymer-silicon composites under
more realistic scenarios
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
- …
