1,720,961 research outputs found
Characterization and application of large disposable shaking bioreactors
No full textApplication of a shaking bioreactor system at pilot-scale level is presented in this research work. This very simple, versatile and widely used technology was combined with the cylindrical disposable reactors to make it an ideal choice for cultivation of plant, animal and insect cell cultures for pilot-scale production. Cylindrical reactors of size 2L, 20L and 50L were thoroughly characterized in terms of important engineering parameters such as mixing, power consumption, heat transfer rate and oxygen transfer rate. Complete mixing of fluid was achieved within few seconds at shaking frequencies as low as 80 rpm. Power consumption for fluids whose physical properties do not vary drastically over temperature was measured by the temperature method. The method was extended to incorporate changes in fluid physical properties such as viscosity, density etc. over temperature. Operating conditions where poor mixing might be observed were identified and a non-dimensional description of power consumption is given for the reactor system. High rates of heat generation were observed in 20L and 50L reactors especially for shaking frequencies higher than 230 rpm. Experiments revealed maximum of 16 K and 30 K increase in fluid temperature for water and a 80% glycerol/water mixture at 300 rpm, respectively. Although thorough ventilation may not be mandatory for slow growing animal and insect cell culture, a thorough ventilation of the surrounding atmosphere is mandatory, especially for high cell density cultivation of fast growing plant cell culture systems e.g. Nicotiana tabacum suspension culture to avoid any temperature stress. Oxygen transfer rate was measured by a well researched sulfite oxidation method. The maximum value of oxygen transfer rate measured in 20L and 50L reactors were 0.032 mol/L/h and 0.028 mol/L/h, respectively. Mass transfer coefficient was correlated with respect to energy dissipation. A therapeutic protein production process based on relatively less hydro-mechanical stress sensitive and one of the fastest growing N. tabacum plant cell suspension culture was successfully scaled-up from a 250 mL shake flask culture to 50L cylindrical disposable shaking bioreactor. The cell growth and protein production was comparable to that observed in other bioreactor systems. An animal cell culture process based on hybridoma-cmyc cells was also scaled-up successfully to a 2L cylindrical disposable shaking bioreactor
Characterization and application of large disposable shaking bioreactors
No full textApplication of a shaking bioreactor system at pilot-scale level is presented in this research work. This very simple, versatile and widely used technology was combined with the cylindrical disposable reactors to make it an ideal choice for cultivation of plant, animal and insect cell cultures for pilot-scale production. Cylindrical reactors of size 2L, 20L and 50L were thoroughly characterized in terms of important engineering parameters such as mixing, power consumption, heat transfer rate and oxygen transfer rate. Complete mixing of fluid was achieved within few seconds at shaking frequencies as low as 80 rpm. Power consumption for fluids whose physical properties do not vary drastically over temperature was measured by the temperature method. The method was extended to incorporate changes in fluid physical properties such as viscosity, density etc. over temperature. Operating conditions where poor mixing might be observed were identified and a non-dimensional description of power consumption is given for the reactor system. High rates of heat generation were observed in 20L and 50L reactors especially for shaking frequencies higher than 230 rpm. Experiments revealed maximum of 16 K and 30 K increase in fluid temperature for water and a 80% glycerol/water mixture at 300 rpm, respectively. Although thorough ventilation may not be mandatory for slow growing animal and insect cell culture, a thorough ventilation of the surrounding atmosphere is mandatory, especially for high cell density cultivation of fast growing plant cell culture systems e.g. Nicotiana tabacum suspension culture to avoid any temperature stress. Oxygen transfer rate was measured by a well researched sulfite oxidation method. The maximum value of oxygen transfer rate measured in 20L and 50L reactors were 0.032 mol/L/h and 0.028 mol/L/h, respectively. Mass transfer coefficient was correlated with respect to energy dissipation. A therapeutic protein production process based on relatively less hydro-mechanical stress sensitive and one of the fastest growing N. tabacum plant cell suspension culture was successfully scaled-up from a 250 mL shake flask culture to 50L cylindrical disposable shaking bioreactor. The cell growth and protein production was comparable to that observed in other bioreactor systems. An animal cell culture process based on hybridoma-cmyc cells was also scaled-up successfully to a 2L cylindrical disposable shaking bioreactor
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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