1,720,958 research outputs found
Wnt1 Accelerates an Ex Vivo Expansion of Human Cord Blood CD34+CD38− Cells
Get PDFCord blood hematopoietic stem cells (CB-HSCs) transplantation has been increasing gradually with facing the limitation of insufficient quantity of HSCs in each CB unit. Therefore, efficient expansion methods which can maintain stem cell characteristics are needed. In this study, umbilical CB-CD34+ cells were cultured in two different cytokine cocktails: 4 factors (4F = Flt3-L, SCF, IL-6, and TPO) and 5 factors (5F = Wnt1 + 4F) in both serum and serum-free media. The data revealed that the best condition to accelerate an expansion of CD34+CD38− cells was serum-free culture condition supplemented with 5F (5F KSR). This condition yielded 24.3 ± 2.1 folds increase of CD34+CD38− cells. The expanded cells exhibited CD34+ CD38− CD133+ CD71low CD33low CD3− CD19− markers, expressed nanog, oct3/4, c-myc, and sox2 genes, and maintained differentiation potential into lymphoid, erythroid and myeloid lineages. The achievement of CD34+CD38− cells expansion may overcome an insufficient quantity of the cells leading to the improvement of the stem cell transplantation. Altogether, our findings highlight the role of Wnt1 and the new culture condition in stimulating hematopoietic stem/progenitor cells expansion which may offer a new therapeutic avenue for cord blood transplantation, regenerative medicine, stem cell bank applications, and other clinical applications in the future
Antimicrobial resistance of Enterococcus spp. isolated from Thai fermented pork in Chiang Rai Province, Thailand
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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
Advanced Amperometric Respiration Assay for Antimicrobial Susceptibility Testing
No full textA ferricyanide-based electrochemical
cell respiration assay was
adapted for use in broad-spectrum antimicrobial susceptibility testing
(AST). Total bacterial respiration was converted into faradaic current
by electro-oxidation of ferrocyanide, produced when ferricyanide is
reduced by bacterial electron-transport. For Escherichia
coli (E. coli), the
signal was linear with 5–13 × 108 colony-forming
units in measuring buffer. For AST, test cells were treated with drugs
before ferricyanide addition; cell counts from the amperometric assay
provided a measure of drug-induced cell death. Initial trials with
six antimicrobial agents produced incorrect susceptibility classifications
for drugs that were electroactive at the potential used to detect
ferrocyanide or which affected cellular respiration rates. We therefore
changed the procedure from drug-treatment and assay in the same buffer
to sequential drug exposure in treatment buffer, centrifugal separation
of surviving cells, cell resuspension, incubation in the presence
of ferricyanide and finally ferrocyanide amperometry in drug-free
buffer. Data analysis with E. coli led
to an activity classification that agreed with cell culture-based
ASTs, obtained by a quicker, more convenient procedure. The potential
of this approach was confirmed by trials with the highly virulent
bacterium Burkholderia pseudomallei, a particularly antimicrobial-resistant pathogen that is the cause
of lethal melioidosis in tropical climates and is currently of concern
as a potential bioterrorism agent
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
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