1,720,965 research outputs found
Fluid Dynamics and Power Consumptions in a Single Use Stirred Tank Adopted in the Pharmaceutical Industry
Get PDFSingle use bioreactors (SUB) are recurrently adopted within the pharmaceutical
industry since they offer several advantages with respect to traditional bioreactors.
Generally, they consist of a stainless-steel container with a bag and an integrated
impeller for handling (mixing stage), storage (post mixing stage I) and transfer (post
mixing stage II) of formulated products. In this work, one of the single use bioreactor
types, the Flexel-Levmixer by Sartorius, is investigated. It is a vessel with a square
section stirred with a bottom impeller, for which little information is available in the
literature, thus making troubleshooting and optimization difficult. To address this issue, a combination of experimental techniques, namely Particle Image Velocimetry, and torque sensors based on strain gauges, are selected for the investigation aimed at the understanding of the fluid dynamics and power consumption with different filling levels and impeller speeds
Power and fluid stress in disposable square stirred tank to streamline pharmaceutical process development
No full textSingle-use systems have quickly become a standard in biopharmaceutical manufacturing due to their superior operational efficiency, flexibility and cost-effectiveness. Despite their recent and intensive use, disposable stirred tanks are not fully understood and require further characterization. Single-use square stirred tanks may exhibit unusual power consumption that may impact drug substances and drug product critical quality attributes. In this work, we use torque measurements and particle image velocimetry to validate a Computational Fluid Dynamics
model designed to elucidate the fluid dynamics in a transparent replica of the Flexel® LevMixer® 50 L. Using the validated model and exploiting the renormalization group k-ε two filling-volume-dependent behaviors were identified: (i) the Swirling flow regime, characterized by low power consumption per unit volume, and (ii) the Engulfed flow regime, which requires significantly higher power. For both regimes, fluid stress induced by the mechanical agitation from the impeller is thoroughly analyzed for intensity and frequency. A strong correlation between fluid stress and power consumption is demonstrated, with implications for pharmaceutical process
development involving stress-sensitive drug substances and products. These findings, which correlate power consumption with fluid stress, can streamline drug development in the pharmaceutical industry and potentially support future development of new process analytical technologies to better control drug substance and drug product quality attributes
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
- …
