1,721,197 research outputs found
Effect of hypoosmotic pressure on cell growth and antibody production in recombinant Chinese hamster ovary cell culture
No full textTo determine the response of recombinant Chinese hamster ovary (rCHO) cells subjected to hypoosmotic pressure, rCHO cells (CS13*-1.0) producing a chimeric antibody were cultivated in the hypoosmolar medium resulting from NaCl subtraction. At hypoosmotic pressure, CS13*-1.0 cells displayed decreased specific growth rate (μ) and increased specific antibody productivity (qAb). When the medium osmolality was decreased from 300 mOsm kg (physiological osmolality) to 150 mOsm kg, μ was decreased by 68% and qAb was increased by 128%. To understand the mechanism of enhanced qAb resulting from hypoosmotic pressure, cellular responses of cells in the exponential phase of growth were observed at the transcription level. Total cytoplasmic RNA content per cell at 150 mOsm kg was increased by 140%, compared with that at 300 mOsm kg. On a per μg RNA basis, immunoglobulin (Ig) mRNA levels at 150 mOsm kg were comparable to those at 300 mOsm kg, indicating that hypoosmotic pressure did not lead to the preferential transcription of Ig mRNAs. Taken together, the data obtained here suggest that the increase in total RNA pool is primarily responsible for the enhanced qAb of CS 13*1.0 cells subjected to hypoosmotic pressure
Radiation-hardening of low noise readout integrated circuit for infrared focal plane arrays
No full textA new distortion measure for spectral quantization based on the LSF intermodel interlacing property
No full textThe line spectral frequencies (LSFs) extracted from successive analysis orders are interlaced with each other. This intermodel interlacing property gives a new relationship between the closeness of LSFs and their spectral sensitivities, which motivates a new weighting function for LSF distortion measurement. By applying this new weighting function to LSF quantization, we have achieved a significantly better performance than the conventional heuristic weighting functions in both clean and noise environments. In addition, the proposed weighting function gives better performance than the weighting function based on a high-rate approximation (Gardner weighting (GW)) [W.R. Gardner, B.D. Rao, IEEE Trans. Speech Audio Processing 3 (5) (1995) 367] in noise environments while their performances are comparable in clean environments. Moreover, the complexity of the proposed weighting function is much lower than that of the GW function. (C) 2001 Elsevier Science B.V. All rights reserved.
Tunable single-frequency Er3+-doped fiber laser using all-fiber acousto-optic bandpass filter
No full textEffects of cloned gene dosage on the response of recombinant CHO cells to hyperosmotic pressure in regard to cell growth and antibody production
No full textThe effect of cloned gene dosage on growth and product formation under hyperosmotic conditions has been studied using recombinant Chinese hamster ovary (rCHO) cell lines producing chimeric antibody. Batch cultures of four rCHO cell lines carrying different numbers of antibody gene copies were carried out using the hyperosmolar medium. Depending on cloned gene dosage, hyperosmotic pressure decreased specific growth rate (μ) and increased specific antibody productivity (q Ab) to a different degree. The cell line with lower cloned gene dosage displayed more significant enhancement in q Ab and less reduction in μ at hyperosmolalities. However, the cell line with higher cloned gene dosage still yielded higher maximum antibody concentration at hyperosmolality up to 469 mOsm/kg. Northern blot analysis showed a positive relationship between immunoglobulin mRNA level per cell and q Ab, indicating that transcriptional regulation was involved in the response of rCHO cells to hyperosmotic pressure. Cell cycle analysis showed that hyperosmotic pressure induced G 1-phase arrest, suggesting that the increase of cell population in G 1-phase may contribute in part to enhanced q Ab at hyperosmolality. Taken together, although the cell line with lower cloned gene dosage displayed more significant enhancement in q Ab at hyperosmolality, the factor that determined the maximum antibody concentration in hyperosmotic rCHO cell cultures was almost exclusively the gene dosage
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
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