1,720,954 research outputs found
Optimal dosage and recycle of cellulases for efficient biomass saccharification of cardoon and giant reed
No full textThe deployment of sugar-based biorefineries is limited by the availability of feedstocks and by the cost of enzymes. Cynara cardunculus and Arundo donax are relevant non-food crops for the development of sugar-based biorefineries. Enzymatic hydrolysis of C. cardunculus and A. donax stalks have been optimized in terms of biocatalyst dosage and reuse. Optimal utilization of a commercial biocatalyst cocktail was achieved assessing the enzyme adsorption on the biomass slurry prior to the hydrolysis stage. The partitioning of cellulases between the liquid the substrate has been characterized for raw and pretreated biomasses. Enzyme uptakes up to 18 mg/g were recorded with 5 % biomass slurries and 0.2–3 g/L initial enzyme concentrations for both C. cardunculus and A. donax. The nearly irreversible nature of the enzyme adsorption allowed a partial recovery of the unbound biocatalyst and the polysaccharides hydrolysis by adsorbed biocatalysts. In the best condition, 89 % glucans conversion was obtained in pretreated cardoon with 4 mg/g loading of adsorbed cellulases (lower than the saturation level) and in giant reed with 13 mg/g. Notably, the residual activity of the unbound biocatalyst was sufficient to hydrolyse more than 65 and 75 % of glucans in pretreated cardoon and giant reed, respectively. The proposed method can be applied routinely to any biorefinery feedstock and both commercial and in-situ produced cocktails to minimize the enzyme dosage
Characterization of Laccase Adsorption on Lignocellulosic Biomasses
Full text linkBiorefinery is a valid alternative to fossil-based processes through the transformation of lignocellulosic biomasses (LB) into a spectrum of chemicals and biofuels (Cherubini, 2010). The sugar-based platform consists of I) one or more biomass pretreatments aimed at modifying/removing lignin; II) cellulose and hemicellulose enzymatic hydrolysis; III) the fermentation of the released pentose and hexose sugars. Pretreatment of lignocellulosic biomass is a key step. Biochemical pretreatments may be the best alternative in terms of process sustainability. Laccases – multicopper oxidoreductases - are among the most proposed enzymes for this purpose. The present study reports the adsorption of a recombinant fungal laccase - PoxA1b, previously proposed for the delignification of several LBs - on coffee silverskin and Cardoon stalks. The milled and sieved biomasses (0.5 - 1 mm) were dispersed in PoxA1b solutions at several initial enzyme concentrations. The preliminary characterization pointed out two occurring phenomena: the adsorption of the laccases on the biomass surface, and its effect on the further adsorption of cellulases in the enzymatic hydrolysis step. Perspectives on future studies include tuning the adsorption-related phenomena and maximising the impact of the biochemical pretreatments in the delignification of LBs for biorefinery purposes
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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