1,721,161 research outputs found
Leaching of endocrine disrupting chemicals from plastic food packaging – In vitro toxicity and chemical composition
No full text<p><span>Plastics are chemically highly complex materials. More than 10,000 substances are used in the production of plastics (e.g., plasticizers, antioxidants) and even more non-intentionally added substances (e.g., reaction byproducts, impurities) are associated with them. While there is abundant scientific evidence that some compounds used in plastics, such as bisphenols and phthalates, are endocrine disrupting chemicals, little is known about the composition and toxicity of the complex mixtures of chemicals leaching from everyday plastic products. Therefore, this study aims at characterizing the <em>in vitro</em> toxicity and the chemical composition of leachates from plastic food contact articles (FCAs) as relevant sources of human exposure. </span><span>Fourteen plastic FCAs covering the seven polymer types with the highest global market share were leached into water and a water-ethanol mixture for 10 days at 40°C according to European Regulation 10/2011/EU. The leachates were analyzed with reporter gene assays for a set of nuclear receptors relevant to human health, including pregnane X receptor (PXR), peroxisome proliferator-activated receptor gamma (PPARγ), estrogen receptors alpha (ERα), and androgen receptor (AR). Further, these plastic mixtures were analyzed using non-target high-resolution mass spectrometry to quantify the number of chemical features and tentatively identify the chemicals leaching from the FCAs. <span>Thirteen of the fourteen FCA leachates interfered with at least one of the nuclear receptors. PXR and PPARg were the predominant targets of the plastic chemicals, but both steroid receptors were also activated or inhibited by several samples. The water leachates were less toxic than the water-ethanol leachates and none of the latter was estrogenic. Also, lower numbers of chemicals were leaching into water as compared to water-ethanol mixture. To identify the active compounds in these complex mixtures, an effect-directed analysis will be performed. This research shows that plastic FCAs leach endocrine disrupting chemicals into food simulants and highlights the importance of analyzing whole mixtures of finished plastic products to cover the toxicity of unknown compounds and mixtures.</span></span></p>
<p><em><span>Acknowledgment</span></em><span> - This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 860720.</span></p>
Raw data for "Migration of endocrine and metabolism disrupting chemicals from plastic food packaging."
No full textThis dataset contains the raw data of the chemical analysis described in the associated publication, namely the mass spectral data of the plastic extracts and migrates analyzed using UPLC-QTOF-DDA. For experimental details on the nontarget analysis, see the Supporting Information of the publication. The data uploaded here are the Waters .raw files converted to the open mzML format which can be assessed using text editors. Each file contains the individual mass spectral data of a sample. They are labelled with the sample name corresponding to the samples described in Table 1 of the publication. The sample names denote the polymer type of the plastic product. PB refers to the procedural blanks, MeOH refers to the methanol used as a solvent, EtOH10 (10% ethanol), EtOH50 (50% ethanol) and H2O refer to the food simulants used for the migration. POS and NEG indicate the ionization mode. BeforeSPE refers to samples analyzed prior to the solid phase extraction
Endocrine toxicity and chemical composition of plastic products.
No full text<p>Besides the physical characteristics of plastic particles such as size or shape, the chemical composition of the plastic particle can contribute to its toxicity. Plastics are chemically highly complex products. For instance, more than 10,000 substances are intentionally used in the production of plastics (e.g., plasticizers, antioxidants) and even more non-intentionally added substances (e.g., reaction byproducts, impurities) are associated with them. While there is abundant scientific evidence that some chemicals used in plastics, such as bisphenols and phthalates, are endocrine disruptors, little is known about the composition and the toxicity of these complex mixtures of chemical. Therefore, this study aims at characterizing both using plastic food contact articles (FCA) as relevant sources of exposure to humans and the environment. Thirty-nine plastic FCAs covering the seven polymer types with the highest global waste share were extracted and analyzed with reporter gene assays for a set of nuclear receptors relevant for human health, including pregnane X receptor (PXR), peroxisome proliferator receptor gamma (PPARγ), estrogen receptors alpha (ERα) and androgen receptor (AR). Further, these plastic extracts were analyzed using non-target high-resolution mass spectrometry to quantify the number of chemical features and tentatively identify the chemicals present in the FCAs. The chemicals extracted from 36 out of 39 FCAs activated or inhibited one or more receptors with activities up to 100% of the respective reference compounds. The PXR was activated by 36, the PPARγ by 23, the ERα by 18 samples, while the AR was inhibited by 14 of 39 samples. In total, we detected >16 000 unique chemical features with the number of features per sample ranging from 37 to 10,000. Only 17% of the chemical features were tentatively identified using spectral libraries and in silico tools. This research highlights the importance of analyzing whole mixtures and contributes to improve our understanding of plastics as a source of exposure to endocrine disrupting chemicals.</p>
<p>Acknowledgement - This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 860720.</p>
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
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