1,721,004 research outputs found
EVALUATION OF THE IMPACT OF DIETARY INTERVENTIONS ON THE HUMAN INTESTINAL MICROBIAL ECOSYSTEM THROUGH IMPROVED BIOINFORMATICS AND STATISTICS
Get PDFThe aim of this PhD work was the characterization of the intestinal microbial ecosystem through bioinformatic and statistical analyses of the microbiomics data originated from three studies carried out on different human populations: healthy (non-diseased) adults, hyperlipidemic and normo-lipidemic children and adolescents, and subjects with diagnosed irritable bowel syndrome (IBS).
Specifically, the three studies presented in this PhD theses were as follows:
• Probiotic crossover intervention study: A randomized, double-blind, crossover, placebo-controlled intervention study was carried out to determine the impact of a Bifidobacterium bifidum strain on the IME of adult healthy volunteers.
• Children’s dyslipidemia single arm intervention study: In this trial, the IME of children and adolescents with primary hyperlipidemia (a risk factor for cardiovascular diseases) was compared with the IME of control (normo-lipidemic) group. In addition, the modulatory effect of the regular intake of hazelnuts on hyperlipidemic subjects’s IME was examines in order to evaluate if the modulation of IME by hazelnuts ameliorates the lipid profile.
• Irritable bowel syndrome (IBS) observational study: The aim of this trial was the characterization of the IME in human subjects affected by IBS. The characterization was performed through the analysis of the bacterial communities present in the faecal samples collected during a multicentre intervention trial (Cremon et al., 2017). Irritable bowel syndrome is the most common gastrointestinal disorder in western countries. IBS is conventionally classified in four different subtypes based on bowel clinical symptoms: constipation, diarrhoea, alternating constipation and diarrhoea, and unsubtyped IBS. Clinical and immunological data collected during the trial were used to investigate the potential correlations between the IME characteristic for a specific IBS subtypes and the physiological and clinical parameters of the host, including bowel symptoms, faecal levels of IgA and cytokines, and depression/anxiety scores.
The analysis of the data collected during the three studies presented in this PhD thesis revealed significant correlations between the intestinal microbial ecosystem and specific physiological parameters, characteristic for the physiological conditions under study. Therefore, these findings suggest that the differential abundance of specific OTUs could be used as a biomarker for a specific host condition.
Conclusion of the probiotic B. bifidum Bb crossover intervention trial
The intervention trial based on the administration of B. bifidum strain Bb has shown that the probiotic treatment modified the relative abundances of bacterial taxa that have often been associated with healthy conditions. The treatment modulated the faecal levels of butyrate, a microbial metabolite exerting multiple effects on gut health. Therefore, the daily consumption of B. bifidum Bb cells may positively affect human health; however, as for most dietary interventions, the current state of knowledge does not allow us to better define the significance of any taxonomic or metabolite changes of the intestinal microbial ecosystem on the host health.
Conclusion of children’s dyslipidemia single arm intervention trial
The results of this study support the hypothesis that young individuals with primary hyperlipidemia possess an dysbiotic intestinal microbial ecosystem, which could plausibly contribute to the abnormal lipid profile of these subjects. A limitation of this study is the small sample size, which may reduce the potential robustness of the obtained results. Moreover, further studies focusing on the mechanisms involved in such hypothesized association are warranted.
Our study is the first human trial investigating the potential role of hazelnuts as IME modulator and, in specific, suggests that a dietary intervention with hazelnut could be an effective and practical strategy to positively modulate the IME of hyperlipidemic subjects.
Conclusion of the IBS-subtypes observational study
This descriptive study demonstrates that the altered distribution of bacteria within the Gram-positive order Clostridiales distinguishes the intestinal microbial ecosystem of IBS subtypes, plausibly contributing to the observed altered faecal levels of the SCFAs acetate, butyrate and propionate. Our study proposes intestinal Clostridiales and colonic SCFAs as IBS subtypes biomarkers that can also potentially represent therapeutic targets. In addition, this study supports the notion that distinct therapeutic approaches should be developed for the different IBS subtype
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
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
Consumption of a bifidobacterium bifidum strain for 4 weeks modulates dominant intestinal bacterial taxa and fecal butyrate in healthy adults
Get PDFModulation of the intestinal microbial ecosystem (IME) is a useful target to establish probiotic efficacy in a healthy population. We conducted a randomized, double-blind, crossover, and placebo-controlled intervention study to determine the impact of Bifidobacterium bifidum strain Bb on the IME of adult healthy volunteers of both sexes. High-throughput 16S rRNA gene sequencing was used to characterize the fecal microbiota before and after 4 weeks of daily probiotic cell consumption. The intake of approximately one billion live B. bifidum cells affected the relative abundance of dominant taxa in the fecal microbiota and modulated fecal butyrate levels. Specifically, Prevotellaceae (P = 0.041) and Prevotella (P = 0.034) were significantly decreased, whereas Ruminococcaceae (P = 0.039) and Rikenellaceae (P = 0.010) were significantly increased. We also observed that the probiotic intervention modulated the fecal concentrations of butyrate in a manner dependent on the initial levels of short-chain fatty acids (SCFAs). In conclusion, our study demonstrates that a single daily administration of Bifidobacterium bifidum strain Bb can significantly modify the IME in healthy (not diseased) adults. These findings demonstrate the need to reassess the notion that probiotics do not influence the complex and stable IME of a healthy individual
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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