1,720,985 research outputs found
Azelaic Acid: A Bio-Based Building Block for Biodegradable Polymers
Full text linkThe production of fine chemicals, new materials and products from renewable
feedstocks represents a continuous challenge. Several procedures have been reported in
the literature or patented in the last decade for the main biomass components:
carbohydrates (75%), lignins (20%), fats and oils (5%) [1]. Regarding oleochemical
developments, the oxidative cleavage of unsaturated fatty acids to produce dicarboxylic
acids, hydroxy acids, and amino acids has received great attention in the last decade [2].
Two main oleochemical products obtained by the cleavage of unsaturated fatty acids are
sebacic acid and azelaic acid.
Azelaic acid (AzA) is a naturally occurring saturated nine carbon atom dicarboxylic
acid found in whole grains, wheat, rye and barley [2], first detected in rancid fats. It can
be formed endogenously from substrates such as longer-chain dicarboxylic acids and
processes like the metabolism of oleic acid, and ψ-oxidation of monocarboxylic acids. The
azelaic acid market is predicted to reach USD 160 million by 2023 and the applications
include pharmacological ingredients, polymers, plastics, lubricants and materials for
electronics [3]. The aim of the present review is to highlight the potential of azelaic acid
as powerful building block for the synthesis of bio-based and biodegradable polymers,
with a special emphasis on the green synthetic routes, embracing both chemical and
enzymatic methods
Enzymatic synthesis and structural modeling of bio-based oligoesters as an approach for fast screening of marine biodegradation and ecotoxicity
No full textWithout prejudice to the fact that biodegradability inherently signifies a desirable trait in plastic
products, nor does it automatically grant them a sustainable "license", the present investigation
provides insights into the relationships between the chemical structure and properties of bio-based
polymers. This facilitates the rational design of new polymers and materials tailored to specific uses
and applications. Given the widespread use of esters and polyesters in products such as cosmetics,
fishing nets, food packaging, etc., there is a critical need for stringent eco-design criteria based on
biodegradability and ecotoxicity studies. Furthermore, it is crucial to not only study the
biodegradability of polymers but also to assess the toxicity and biodegradability of individual
monomers within the context of microplastic research. Our results reveal that aromatic monomers
accumulate when inoculum from the Adriatic Sea is used. However, we have demonstrated that the
slower degradation observed in certain sites is affected by industrial and urban pollution, suggesting
that ecosystems adapt to non-natural chemical pollutants. While clean seas are more susceptible to
toxic chemical buildup, biotic catalytic activities offer promise for plastic pollution mitigation.
Furthermore, the integration of experimental and computational methods provides a rapid screening
tool for sustainable monomers and oligomers, with bio-based alternatives showing promise
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
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