1,720,988 research outputs found
Small intestine contrast ultrasonography
No full textThe entire small bowel can be visualized on ultrasonography after ingestion of nonabsorbable, isosmotic polyethylene glycol electrolyte balanced oral solution, termed small intestine contrast ultrasonography. The aims of this study were to assess whether the ingestion of different volumes of sonographic contrast solution may differently affect (1) small bowel distention and thus its sonographic appearance and (2) the time to visualize the entire small intestine. An additional aim was to identify the minimal amount of contrast solution necessary to visualize the entire small bowel. An ultrasonographic examination of the abdomen was performed twice in six healthy subjects after the ingestion of the isosmotic polyethylene glycol solution. During the first investigation each subject was asked to drink increasing amounts of sonographic contrast solution until the jejunum was visualized at ultrasonography. During the second investigation each subject was asked to drink increasing amounts of sonographic contrast solution, not to exceed a total volume of 260 ml. At the first examination the entire small bowel was visualized 39.3±17 min after ingestion of 647±105 ml of contrast solution. At the second examination the entire small bowel was visualized 43.5±13.5 min (not significant with respect to the first study) after the ingestion of 239±32 ml of contrast solution (P<0.01 versus the first study). The mean luminal diameter and wall thickness at three intestinal levels did not differ in the two studies and were not statistically related to the amount of ingested sonographic contrast solution. Loose stools were the only side effect and were reported after the ingestion of more than 600 ml. Ultrasonography offers reproducible information on the morphology of the contrast agent-filled small bowel after ingestion of a wide range of volumes (175 to 820 ml) of isosmotic polyethylene glycol electrolyte balanced solution. On average, the entire small intestine could be visualized on ultrasonography by about 45 min after the ingestion of 600 ml or less of contrast solution without any side effects
Ultrasonography of the small bowel after oral administration of anechoic contrast solution
No full textUltrasonography of the small bowel after oral administration of anechoic contrast solutio
Gallbladder volume variations after meal ingestion
No full textObjective: To assess gallbladder (GB) volume variations in response to a standard meal.
Methods: We assessed these variations with ultrasonography at brief intervals over the postprandial period, which included the emptying and refilling phases of the GB.
Results: During both emptying and refilling of the GB, the volume fluctuated continuously, with brief alternating volume decrements and increments. The phases of emptying and refilling appear to be the net result of the algebraic sum of these volume fluctuations. In the emptying phase, the volume decrements showed a greater volume (35.7 +/- 10.7 ml vs. 14.8 +/- 8.4 ml) and lasted longer (158 +/- 37 min vs. 85 +/- 44 min) than the volume increments, whereas the opposite took place in the refilling phase (4.3 +/- 3.4 ml vs. 16.4 +/- 12.2 ml; 39 +/- 20 min vs. 84 +/- 37 min).
Conclusion: It is probable that the continuous GB volume fluctuations are the expression of hepatic bile recycling in the GB during the entire postprandial period, and the amount of bile recycled by the GB is greater during the emptying than the refilling phase
Antro-pyloric contractile patterns and transpyloric flow after meal ingestion in humans
No full textObjective: The present study aimed to evaluate the patterns of antral contractility and pylorus opening and closure in relation to transpyloric flow of a nutrient liquid meal. Methods: Ultrasound images of the antro- pyloro-duodenal tract were continuously tape-recorded in healthy volunteers for 1 h postprandially and were reviewed twice later by independent observers. Episodes and patterns of pylorus opening and closure, antral-wall contractions, and transpyloric flow were assessed separately and their time relations were identified. Results: Transpyloric flow (forward, 56% ± 13%; retrograde, 19% ± 11%; and to and fro, 25% ± 14%) occurred essentially during episodes of prolonged pylorus opening not associated with occlusive antral or duodenal proximal contraction, which represented the antro-pyloro- duodenal common chamber. The antro-pyloro-duodenal common chamber lasted on average 36 ± 12 s and represented 41% ± 12% of the total observation period. Different patterns of antral contractions were identified according to whether they reached or occluded the terminal antrum and pylorus. Preterminal antral contractions (46% ± 12%) did not propagate beyond the proximal two thirds of the antrum. Terminal antral contractions (54% ± 12%) propagated along the entire antrum and could either occlude (20% ± 9%) or not occlude (42% ± 17%) the lumen. Pyloric opening independent of antral contractions and related to nonocclusive antral contractions could occur equally at the onset of the antro-pyloro-duodenal common chamber. Pyloric closure independent of antral contractions put an end to transpyloric flow in 73% ± 6% of the antro-pyloro-duodenal common chamber. Conclusions: The final passage of contents from the stomach to the duodenum after the ingestion of a caloric liquid meal is the result of one or more episodes of uni- or bi- directional transpyloric flow, which are regulated by several motor events. The contractile states of the antrum and pylorus show specific features that variably interrelate to provide mixing and to regulate the transpyloric flow of ingesta. A crucial regulator of transpyloric flow appears to be the spatiotemporal relation between antral contractions and pyloric closure rather than the contractile events per se. An equal number of pyloric openings related, and unrelated, to antral contractions appears to determine the onset of the antro-pyloro-duodenal common chamber and, thus, of transpyloric flow. Pyloric closure unrelated to antral contractions appears to be the main mechanism that interrupts transpyloric flow. In conclusion, it appears that the antro-pyloro-duodenal tract acts as a functional unit in the digestion of a liquid caloric meal
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
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