1,721,202 research outputs found
Characterization of fibrous mordenite: A first step for the evaluation of its potential toxicity
Full text linkIn nature, a huge number of unregulated minerals fibers share the same characteristics as asbestos and therefore have potential adverse health effects. However, in addition to asbestos minerals, only fluoro-edenite and erionite are currently classified as toxic/pathogenic agents by the International Agency for Research on Cancer (IARC). Mordenite is one of the most abundant zeolites in nature and commonly occurs with a fibrous crystalline habit. The goal of this paper is to highlight how fibrous mordenite shares several common features with the well-known carcinogenic fibrous erionite. In particular, this study has shown that the morphology, biodurability, and surface characteristics of mordenite fibers are similar to those of erionite and asbestos. These properties make fibrous mordenite potentially toxic and exposure to its fibers can be associated with deadly diseases such as those associated with regulated mineral fibers. Since the presence of fibrous mordenite concerns widespread geological formations, this mineral fiber should be considered dangerous for health and the precautionary approach should be applied when this material is handled. Future in vitro and in vivo tests are necessary to provide further experimental confirmation of the outcome of this work
Letter to the Editor: Comments on the paper of Wylie and Korchevskiy – Carcinogenicity of fibrous glaucophane: How should we fill the data gaps?
Full text linkAssessing the human health risk of mineral fibres is an intricate task. In the recent article by Wylie and Korchevskiy (2021) – Carcinogenicity of fibrous glaucophane: how to fill data gaps? (Curr. Res. Toxicol. Vol. 2, pp. 202–203), the authors discuss the potential toxicity and pathogenicity of fibrous glaucophane from the Franciscan Complex, California (USA). Because most of the points of discussion concerns the mineral fibre toxicity/pathogenicity model developed by our research group and the application to the case of fibrous glaucophane (Gualtieri, 2021, Curr. Res. Toxicol. Vol. 2, pp. 42–52), the aim of this Letter is to clear some basic issues, to fill some information gaps and, with a constructive spirit, to provide a complete picture on this topic
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
Commercial brucite, a worldwide used raw material deemed safe, can be contaminated by asbestos
No full textBrucite is a raw material used in several applications and worldwide traded. The main active deposits are located in North America, North Europe and China and the extracted material is worked and delivered all over the world without any particular precaution as it is considered a safe inert product. But is it really true? Applying a consolidated protocol of analysis for the detection and characterization of fibers, we found asbestos in a sample of commercial brucite. The analyzed material is primarily composed of plate-like crystals of brucite; nevertheless, chemical and mineralogical analyses revealed the presence of serpentine, while morphometric observation through electron microscopy confirmed the occurrence of respirable regulated chrysotile (serpentine asbestos) fibers. The individual fibers making up the chrysotile bundles have length >5 μm, width <3 μm, length/width ratio >3, and their concentration in the investigated product is 169 mg/kg (0.02 wt%). Although paragenesis of brucite with chrysotile has been known for a long time, never before was documented a commercial brucite, distributed worldwide, contaminated with asbestos. In the light of these results, we think that certification of the absence of asbestos should be imposed to the brucite mining companies and distributors; otherwise, users should always include a careful inspection on incoming materials, at least by electron microscopy, to rule out the occurrence of asbestos
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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