1,720,961 research outputs found
MRI assessment on the impact of a low FODMAP diet on the gastrointestinal tract
Get PDFIntroduction: Poorly absorbed fermentable carbohydrates (FODMAPs) escape digestion in the small bowel, and enter the colon to be fermented by gut bacteria thus increasing luminal volume. However, in susceptible individuals e.g. Irritable Bowel Syndrome (IBS) sufferers, this may result in gastrointestinal symptoms, due to the rapid emptying of the small bowel producing increased luminal water and distension in the colon from gas producing bacteria. Previous studies have demonstrated the effect of fermentation on FODMAPs by assessing microbial concentration and breath hydrogen. However, the physiological changes in the lumen, particularly in the colon, remain unclear.
Aims: The main purpose of this thesis is to assess the effects of FODMAPs on luminal volume, using magnetic resonance imaging, and how they impact appetite, gastrointestinal symptoms and function.
The hypotheses generated and tested were that:
i) FODMAPs increase luminal volume, causing symptoms in IBS patients
ii) Restriction of FODMAPs reduces luminal volume in patients and healthy volunteers
Methods: Four studies were undertaken, with the first being an observational study and the remainder being RCTs. The first study was a pilot study to compare a validated dietary assessment method with a reference method to quantify FODMAP intake in healthy volunteers (n=37). The second study assessed the effect of a low FODMAP diet versus a high FODMAP diet on gastrointestinal physiology and function in healthy volunteers (n=37; FOG). The third study measured the effect of different physical forms of FODMAPs on gastrointestinal physiology in healthy volunteers (n=18; APPLE). The final study compared the effects of a low FODMAP diet versus habitual diet in patients with IBS (n=27; CRAIGS).
Results: Findings from the first study suggested that the 7-day food diary is more reliable in assessing energy, nutrient and FODMAP intake within the UK population. In the FOG study, colonic volume increased in both groups and fasting breath hydrogen levels declined on the low FODMAP diet. However, fasting breath hydrogen levels increased in those on a high FODMAP diet when supplemented with oligofructose. In the third study, altering the physical form of a meal had an effect on small bowel water content only during the late phase, whereas gastric emptying in healthy volunteers was fastest with apple juice, followed by apple puree and whole apples respectively. In the CRAIGS study, the low FODMAP diet lowered the increase in colonic volume when compared with the habitual diet.
Conclusions: A high FODMAP diet, whether from dietary intake or supplementation, can lead to an increase in colonic volume. In IBS patients this impacts on their overall global symptoms. The unexpected increase with a low FODMAP diet, and the inconclusive effect of fermentation as a result of low breath hydrogen levels, suggests that the role of foods substituted as part of the low FODMAP diet needs further investigation. Meanwhile, altering physical properties of FODMAPs has an impact on luminal volume, but this also needs further investigation. A detailed dietary intake using a 7 day food diary during pre and post dietary intervention is recommended as a measure of compliance
MRI assessment on the impact of a low FODMAP diet on the gastrointestinal tract
Get PDFIntroduction: Poorly absorbed fermentable carbohydrates (FODMAPs) escape digestion in the small bowel, and enter the colon to be fermented by gut bacteria thus increasing luminal volume. However, in susceptible individuals e.g. Irritable Bowel Syndrome (IBS) sufferers, this may result in gastrointestinal symptoms, due to the rapid emptying of the small bowel producing increased luminal water and distension in the colon from gas producing bacteria. Previous studies have demonstrated the effect of fermentation on FODMAPs by assessing microbial concentration and breath hydrogen. However, the physiological changes in the lumen, particularly in the colon, remain unclear.
Aims: The main purpose of this thesis is to assess the effects of FODMAPs on luminal volume, using magnetic resonance imaging, and how they impact appetite, gastrointestinal symptoms and function.
The hypotheses generated and tested were that:
i) FODMAPs increase luminal volume, causing symptoms in IBS patients
ii) Restriction of FODMAPs reduces luminal volume in patients and healthy volunteers
Methods: Four studies were undertaken, with the first being an observational study and the remainder being RCTs. The first study was a pilot study to compare a validated dietary assessment method with a reference method to quantify FODMAP intake in healthy volunteers (n=37). The second study assessed the effect of a low FODMAP diet versus a high FODMAP diet on gastrointestinal physiology and function in healthy volunteers (n=37; FOG). The third study measured the effect of different physical forms of FODMAPs on gastrointestinal physiology in healthy volunteers (n=18; APPLE). The final study compared the effects of a low FODMAP diet versus habitual diet in patients with IBS (n=27; CRAIGS).
Results: Findings from the first study suggested that the 7-day food diary is more reliable in assessing energy, nutrient and FODMAP intake within the UK population. In the FOG study, colonic volume increased in both groups and fasting breath hydrogen levels declined on the low FODMAP diet. However, fasting breath hydrogen levels increased in those on a high FODMAP diet when supplemented with oligofructose. In the third study, altering the physical form of a meal had an effect on small bowel water content only during the late phase, whereas gastric emptying in healthy volunteers was fastest with apple juice, followed by apple puree and whole apples respectively. In the CRAIGS study, the low FODMAP diet lowered the increase in colonic volume when compared with the habitual diet.
Conclusions: A high FODMAP diet, whether from dietary intake or supplementation, can lead to an increase in colonic volume. In IBS patients this impacts on their overall global symptoms. The unexpected increase with a low FODMAP diet, and the inconclusive effect of fermentation as a result of low breath hydrogen levels, suggests that the role of foods substituted as part of the low FODMAP diet needs further investigation. Meanwhile, altering physical properties of FODMAPs has an impact on luminal volume, but this also needs further investigation. A detailed dietary intake using a 7 day food diary during pre and post dietary intervention is recommended as a measure of compliance
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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