342 research outputs found

    Journey to the centre of the lung. The perspective of a mineralogist on the carcinogenic effects of mineral fibres in the lungs

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    This work reviews the bio-chemical mechanisms leading to adverse effects produced when mineral fibres are inhaled and transported in the lungs from the perspective of a mineralogist. The behaviour of three known carcinogenic mineral fibres (crocidolite, chrysotile, and fibrous-asbestiform erionite) during their journey through the upper respiratory tract, the deep respiratory tract and the pleural cavity is discussed. These three fibres have been selected as they are the most socially and economically relevant mineral fibres representative of the classes of chain silicates (amphiboles), layer silicates (serpentine), and framework silicates (zeolites), respectively. Comparison of the behaviour of these fibres is made according to their specific crystal-chemical assemblages and properties. Known biological and subsequent pathologic effects which lead and contribute to carcinogenesis are critically reviewed under the mineralogical perspective and in relation to recent progress in this multidisciplinary field of research. Special attention is given to the understanding of the cause-effect re-lationships for lung cancer and malignant mesothelioma. Comparison with interstitial pulmonary fibrosis, or "asbestosis", will also be made here. This overview highlights open issues, data gaps, and conflicts in the liter-ature for these topics, especially as regards relative potencies of the three mineral fibres under consideration for lung cancer and mesothelioma. Finally, an attempt is made to identify future research lines suitable for a general comprehensive model of the carcinogenicity of mineral fibres

    In vitro acellular dissolution of mineral fibres: A comparative study

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    The study of the mechanisms by which mineral fibres promote adverse effects in both animals and humans is a hot topic of multidisciplinary research with many aspects that still need to be elucidated. Besides length and diameter, a key parameter that determines the toxicity/pathogenicity of a fibre is biopersistence, one component of which is biodurability. In this paper, biodurability of mineral fibres of social and economic importance (chrysotile, amphibole asbestos and fibrous erionite) has been determined for the first time in a systematic comparative way from in vitro acellular dissolution experiments. Dissolution was possible using the Gamble solution as simulated lung fluid (pH = 4 and at body temperature) so to reproduce the macrophage phagolysosome environment. The investigated mineral fibres display very different dissolution rates. For a 0.25 μm thick fibre, the calculated dissolution time of chrysotile is in the range 94-177 days, very short if compared to that of amphibole fibres (49-245 years), and fibrous erionite (181 years). Diffraction and SEM data on the dissolution products evidence that chrysotile rapidly undergoes amorphization with the formation of a nanophasic silica-rich fibrous metastable pseudomorph as first dissolution step whereas amphibole asbestos and fibrous erionite show minor signs of dissolution even after 9-12 months

    To Teach is To Learn: High-School Students, Local University and Informal Science Educators Collaborate in Communicating Science to the Public

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    Background: Informal education, especially if in collaboration with formal education, can be an important vehicle for communicating current research in science to the public as well as significant in drawing the young nearer to science and helping them to understand the inherent processes. Methods: In this paper we describe an international collaboration between a group of high-school students in Italy and Earth scientists and museum professionals from Italy and the US to plan and implement a scientific exhibition on symmetry, a topic chosen because of its connections to both Earth science and evolution. Results: By directly involving the high-school students in the design and implementation of the exhibition, they were given ownership of the project as well as ‘hands-on’ experience of communicating science to the public. The students involved helped design the content and layout of the exhibition, as well as with the design and fabrication of exhibition elements, marketing of the exhibition and evaluation. The design allowed the project manager to collect input from the students on how to make exhibitions more ‘user friendly’ to their age demographic, as well as to children and young adults in general. Although more research on similar projects is needed, evaluation results from this project showed that the response of the students - and of visitors - to the exhibition was significantly positive, and suggest that the project was engaging, cost effective and easy to implement. Conclusions: This project may serve as a template for other formal and informal educators to develop these types of collaborations, using informal science education as a bridge to link science researchers and middle- and high-school students in creating an environment where students learn through actively participating in the public communication of science

    The effect of grinding on tremolite asbestos and anthophyllite asbestos

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    The six commercial asbestos minerals (chrysotile, fibrous actinolite, crocidolite, amosite, fibrous tremolite, and fibrous anthophyllite) are classified by the IARC as carcinogenic to humans. There are currently several lines of research dealing with the inertisation of asbestos minerals among which the dry grinding process has received considerable interest. The effects of dry grinding on tremolite asbestos and anthophyllite asbestos in eccentric vibration mills have not yet been investigated. Along the research line of the mechanical treatment of asbestos, the aim of this study was to evaluate the effects of dry grinding in eccentric vibration mills on the structure, temperature stability, and fibre dimensions of tremolite asbestos from Val d\u2019Ala, (Italy) and UICC standard anthophyllite asbestos from Paakkila mine (Finland) by varying the grinding time (30 s, 5 min, and 10 min). After grinding for 30 s to 10 min, tremolite asbestos and anthophyllite asbestos showed a decrease in dehydroxylation and breakdown temperatures due to the increase in lattice strain and the decrease in crystallinity. Moreover, after grinding up to 10 min, tremolite and anthophyllite fibres were all below the limits defining a countable fibre according to WHO

    Grid-VirtuE: a layered architecture for grid virtual enterprises

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    A grid virtual enterprise is a community of independent enterprises concerned with a particular sector of the economy. Its members (nodes) are small or medium size enterprises (SME) engaged in bilateral transactions. An important principle of a grid virtual enterprise is the lack of any global "guiding force", with each member of the community making its own independent decisions. In this paper we describe Grid-VirtuE, a three-layer architecture for grid virtual enterprises. The top layer of the architecture, representing its ultimate purpose, is an environment in which grid virtual enterprises can be modeled and implemented. This layer is supported by middleware infrastructure for grids, providing a host of grid services, such as node-to-node communication, bilateral transactions, and data collection. The bottom layer is essentially a distributed data warehouse for storing, sharing and analyzing the large amounts of data generated by the grid. Among other functionalities, the warehouse handles the dissemination of data among the members of the grid; it confronts issues of data magnitude with an aging mechanism that aggregates old data at a lower level of detail; and it incorporates privacy-preserving features that retain the confidentiality of individual members. Warehouse information is also used for data and process mining, aimed at analyzing the behavior of the enterprise, and subsequently inducing evolutionary changes that will improve its performance.A grid virtual enterprise is a community of independent enterprises concerned with a particular sector of the economy. Its members (nodes) are small or medium size enterprises (SME) engaged in bilateral transactions. An important principle of a grid virtual enterprise is the lack of any global "guiding force", with each member of the community making its own independent decisions. In this paper we describe Grid-VirtuE, a three-layer architecture for grid virtual enterprises. The top layer of the architecture, representing its ultimate purpose, is an environment in which grid virtual enterprises can be modeled and implemented. This layer is supported by middleware infrastructure for grids, providing a host of grid services, such as node-to-node communication, bilateral transactions, and data collection. The bottom layer is essentially a distributed data warehouse for storing, sharing and analyzing the large amounts of data generated by the grid. Among other functionalities, the warehouse handles the dissemination of data among the members of the grid; it confronts issues of data magnitude with an aging mechanism that aggregates old data at a lower level of detail; and it incorporates privacy-preserving features that retain the confidentiality of individual members. Warehouse information is also used for data and process mining, aimed at analyzing the behavior of the enterprise, and subsequently inducing evolutionary changes that will improve its performance.Monograph's chapter
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