1,720,969 research outputs found
Heat inactivation of fetal bovine serum increases protein contamination of extracellular vesicles
Full text linkIntroduction: Extracellular vesicles (EVs) released in cell cultures are influenced by the cell culture conditions, such as the use of
fetal bovine serum (FBS). FBS contains EVs and it is usually depleted of EVs by ultracentrifugation (UC) and/or heat inactivated
(HI). Several studies have evaluated the effect of different UC protocols for FBS by evaluating both cells and EVs. However, less
is known about the effect of HI on the cells and the released EVs. The aim of this study was therefore to evaluate the effect of HI
on EV purity.
Methods: To determine the effect of heat inactivation, three different protocols were applied based on different combinations of:
1) UC at 118,000 × g for 18h and 2)HI at 56◦C for 30 min. The three conditions tested were: FBS ultracentrifuged but not heat
inactivated (no-HI), FBS heat inactivated before UC (HI-before EV-dep), and FBS heat inactivated after EV depletion (HI-after
EV-dep). The FBS was add to themedia of threemelanoma cell lines (MML1, UM22Ctr and UM22BAP1) at a final concentration
of 10%. After 72h, large and small EVs were isolated by differential UC. The EV purity was determined by protein quantity,
electron microscopy (EM) and nanoparticle tracking analysis (NTA).
Results: The protein quantity (μg/μl) of large EVs was similar in the three conditions analyzed. On the contrary for small EVs,
the protein amount was higher when the HI was performed after EV depletion as compared to HI before the UC and UC alone.
However, significantly more particles were not detected in the HI-after EV-dep which resulted in a lower purity of small EVs in
HI-after EV-dep illustrated by calculating the ratio of number of particles/μg proteins. Presence of contaminants (indicated by
strong background) was observed in EM pictures of small EVs isolated in HI-after EV-dep condition differently from large EV
samples.
Summary/Conclusion: The HI of FBS induces release of contaminating elements that end up in small EVpellets if not previously
removed
Nutraceutical value of Pantelleria capers (Capparis spinosa L.)
No full textUnopened flower buds of Capparis spinosa L. (capers), generally used in the Mediterranean area as food flavoring, are known to be a good source of bioactive compounds. The aim of this work was to evaluate the nutraceutical value of salt-fermented capers collected from different areas of Pantelleria Island (Italy), testing their methylglyoxal and glyoxal trapping capacity and antioxidant activity by 2,2-diphenyl-1-picryl hydrazyl (DPPH), [2,2-azinobis(3-ethylben- zothiazoline-6-sulfonic acid)] diammonium salt (ABTS), and oxygen radical absorbance capacity (ORAC) assays. Hydrophilic extracts were also characterized by high-performance liquid chromatography–electrospray ionization/mass spectrometry. Among 24 detected compounds, several flavonol derivatives and glucosinolates were identified. The levels of kaempferol and quercetin derivatives varied considerably among the five accessions considered (6.46 to 267.93 and 22.39 to 367.14 mg kaempferol and quercetin equivalent /g fresh weight, respectively), with kaempferol derivatives more representative than quercetin ones. Person's coefficient indicated a high correlation between total phenolic content and anti-DPPH radical capacity (R2 = 0.665), as well as between total flavonoid content and antioxidant capacity (by ORAC assay; R2 = 0.888) and between total flavonoid content and glyoxal and methylglyoxal trapping capacity (R2 = 0.918). Results indicate that capers from Pantelleria Island represent a rich source of bioactive compounds with potential nutraceutical relevance. Practical Application: The findings of this study highlight the health benefits of Pantelleria capers consumption due to their composition in antioxidants and their biological properties (antiradical and alpha-dicarbonyls trapping) correlated with the development of a high number of chronic–degenerative diseases. These results are also important for the agricultural and commercial sectors involved in the production of capers from Pantelleria, which received the Protected Geographical Indications recognition
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
- …
