1,720,952 research outputs found
253 - Luke Allen Schwerdtfeger
No full textIntestinal infections impact millions of people each year, often with ineffective treatments available. There is a lack of models capable of studying these infections that recapitulate the guts cellular environment. Addressing this, we placed biopsies from human colon into culture, and maintained the cellular environment observed in vivo, in a dish. Using this model, sex differences in colonic T-cell responses to Salmonella were observed. When culturing biopsy tissue at ~1% oxygen there was an increase in epithelial cell birth compared to atmospheric oxygen. These results signal the need for controlling oxygen and tracking sex when studying colon-microbiome interactions. Purpose: Mammalian intestines maintain a highly complex physiology that survives an extreme oxygen gradient, a mixed population of commensal and pathogenic bacteria, and a heterogeneous cell composition that includes immune, neural, and epithelial elements. Understanding disorders and developing treatment modalities for intestinal disease and infection states requires balancing multiple factors, including sex-dependence. This study begins to account for the impacts of oxygen concentrations in the context of sex, pathogen, and antibiotic exposure. Procedure: Organotypic slices from human colon biopsies provided three-dimensional environments that maintained cellular morphology and relationships, ex vivo. Biopsy slices were used to study impacts of pathogen exposure on lymphocyte counts, and oxygen and antibiotic treatments on epithelial proliferation rates. Results: Sex differences were observed in basal CD3+ T lymphocyte count in human colon, with male patients having over 2-fold more CD3+ T cells than females. When exposed to a strain of Salmonella enterica, male cell counts did not change, while there was a significant increase in CD3+ T cells in biopsy slices taken from females (P < 0.05). For intestinal mucosa, there were greater rates of epithelial cell proliferation in lowered oxygen conditions (1%) than under more standard atmospheric conditions (20%)(P < 0.05). Antibiotic treatment decreased epithelial proliferation in slices maintained in 1% oxygen, but not 20% (P < 0.05). Implications: These results show a baseline T cell sex difference in the human colon that showed a sex-dependent response to pathogen ex vivo. In addition, oxygen concentration impacted colonic epithelial cell proliferation. Together, these results point towards the need to account for oxygen concentration and sex when studying gut-microbe interactions
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
192 - Ian Cook McLean
No full textCurrently, most in vitro experimental models of the intestine rely upon cell lines, and consequently, lack the diverse representation of cells present in vivo. Slices of intestine, removed from living organisms, offer a better representation of in vivo physiology. However, current techniques for maintaining intestinal tissue in vitro are not capable of recapitulating the in vivo environment.
This project utilizes 3D printing and microfluidic principles to design a device that delivers differential flows of media across the two surfaces of intestinal tissue. The device will enable the investigation of complex biological questions that previous models have been unable to address
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
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