1,720,957 research outputs found
Integrated biorefinery strategy for poly(3-hydroxybutyrate) accumulation in Cupriavidus necator DSM 545 using a sugar rich syrup from cereal waste and acetate from gas fermentation
Full text linkPoly(3-hydroxybutyrate) (PHB) is one of the most well-known biodegradable and biocompatible biopolymers
produced by prokaryotic microorganisms. It belongs to the family of polyhydroxyalkanoates (PHAs), and it has
gained significant attention in recent years due to its potential as a sustainable alternative to traditional
petroleum-based plastics. Cupriavidus necator has been identified as a potential producer of PHB for industrial
applications due to its ability to produce high amounts of the polymer under controlled conditions, using a wide
range of waste substrates. In this study, the ability of Cupriavidus necator DSM 545 strain to produce PHB was
tested in a fed-batch strategy providing two different organic substrates. The first is a sugar-based syrup (SBS),
derived from cereal waste. The second is an acetate-rich medium obtained through CO2 -H2 fermentation by the
acetogenic bacterium Acetobacterium woodii. The carbon sources were tested to improve the accumulation of PHB
in the strain. C. necator DSM 545 proved to be able to grow and to perform high accumulation of biopolymer on
waste substrates containing glucose, fructose, and acetate, reaching about 10 g/L of PHB, 83% of biopolymer
accumulation in cell dry mass, in 48 h of fed-batch fermentation in 0.6 L working volume in a bioreactor.
Moreover, a Life Cycle Assessment analysis was performed to evaluate the environmental impact of the process
converting the sugar syrup alone and the integrated one. It demonstrated that the integrated process is more
sustainable and that the most impactful step is the PHB production, followed by the polymer extraction
Cell-surface binding domains from Clostridium cellulovorans can be used for surface display of cellulosomal scaffoldins in Lactococcus lactis
Full text linkEngineering microbial strains combining efficient lignocellulose metabolization and high-value chemical production is a cutting-edge strategy towards cost-sustainable 2nd generation biorefining. Here, protein components of the Clostridium cellulovorans cellulosome were introduced in Lactococcus lactis IL1403, one of the most efficient lactic acid producers but unable to directly ferment cellulose. Cellulosomes are protein complexes with high cellulose depolymerization activity whose synergistic action is supported by scaffolding protein(s) (i.e., scaffoldins). Scaffoldins are involved in bringing enzymes close to each other and often anchor the cellulosome to the cell surface. In this study, three synthetic scaffoldins were engineered by using domains derived from the main scaffoldin CbpA and the Endoglucanase E (EngE) of the C. cellulovorans cellulosome. Special focus was on CbpA X2 and EngE S-layer homology (SLH) domains possibly involved in cell-surface anchoring. The recombinant scaffoldins were successfully introduced in and secreted by L. lactis. Among them, only that carrying the three EngE SLH modules was able to bind to the L. lactis surface although these domains lack the conserved TRAE motif thought to mediate binding with secondary cell wall polysaccharides. The synthetic scaffoldins engineered in this study could serve for assembly of secreted or surface-displayed designer cellulosomes in L. lactis
A practical method for gas changing time estimation using a simple gas-liquid mass transfer model
Full text linkThe present work explains a practical and simple method to calculate the gas changing time of anaerobic systems. It is substantiated under the physics of gas-liquid transfer theory and allows researchers to obtain an approximate value of gas changing time with few measurements of the gas composition in the outlet of the reactor. The only analytical equipment required is a gas analyzer, and calculations can be done using a spreadsheet. Along with the validation of the model, a short guide for its application in the laboratory is introduced. The model fits the experimental data with less than 1% error in the composition of the out-gas when no carbon dioxide is involved. This method will allow savings in valuable resources such as time and gases while providing greater comprehension of the characteristics of the gas-liquid transfer of the studied system
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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