1,720,985 research outputs found
Relazione attivita' I anno dottorato in nutrizione sperimentale e clinica
No full textRelazione i° anno di dottorato in nutrizione sperimentale e clinica dott.ssa emanuela setola
ruolo di una dieta ricca in l-arginina nel modulare l’insulino-resistenza, la disfunzione endoteliale,
lo stress ossidativo in una popolazione di soggetti
affetti da intolleranza ai carboidrati.
L’endotelio è un organo ubiquitario responsabile della regolazione dei processi emodinamici, del rimodellamento vascolare, di processi metabolici, sintetici e infiammatori. La disfunzione endoteliale, caratterizzata da un’alterata secrezione di ossido nitrico, è un importante anomalia riscontrata negli stati di insulino-resistenza. Le alterazioni nella produzione di ossido nitrico contribuiscono al manifestarsi di molte alterazioni precoci fra cui una maggiore espressione di molecole infiammatorie implicate nei processi precoci di aterosclerosi. L'attività vasodilatante endotelio mediata é determinata dall'ossido nitrico, sintetizzato dalla famiglia di enzimi ossido nitrico sintetasi (NOS) a partire dalla L-arginina
AN HEALTHY DIET AND AN HEALTHY FOOD ADDED WITH L-ARGININE: BIOAVAILABILITY AND BENEFICIAL EFFECTS
No full textBackground
The use of L-Arginine as food supplement to a normal diet, in relatively large doses, has been proved to have a salutary effect on cardiovascular diseases and glucose metabolism. L-Arginine was found to be bio-available and effective in the prevention of impairment of glucose metabolism and endothelial dysfunction.
Objective: To obtain a food product having a high content (at least 10%) of L-arginine completely bio-available (> 99%), being also palatable, homogeneous, having low amounts of sugar and optionally suitable for insulin-resistant and/or carbohydrate-intolerant subjects.
Methods
The food product was produced at a low temperature range which prevents the degradation of the amino acid by Maillard reactions or other heat dependent degradations and by means of sonication.
To evaluate the bio-availability and the vascular and metabolic effects of L-Arginine (6.6 g) contained in the food preparation (6 biscuits) compared either to the same food preparation (6 biscuits) without the addition of L-Arginine either to 6.6 g of powdered L-Arginine, seven healthy subjects (2M/5F) participated in the study. It was asked to all subjects to follow a 2000 kcal/die standard diet, according to LARN recommendations and to complete a 3 day food diary (two working days and one holiday day) before every test to obtain accurate information on short-term food intake. Food diaries were evaluated with software to decode foods, modified introducing the L-Arginine contents in more than 800 different foods. The average daily intake of L-Arginine was estimated about 2.5 g/day.
Subjects underwent 3 different tests, in random order, with at least a 14-day interval.
The first test consisted in an oral administration of 6 biscuits containing 1.1 g each of L-arginine for a total of 6.6 g. The portion of 6 biscuits contained total amount of 21.9 g of carbohydrates (17.9 g of starch and 4.0 g of sugars), 3.6 g of proteins, 7.5 g of fats and 4.3 g of fibers. A fixed amount of 250 ml of natural water was taken with the food preparation.
The second test consisted in an oral administration of the 6 biscuits prepared with the same sonication process but without the addition of L-Arginine. A fixed amount of 250 ml of natural water was taken with the food preparation.
The third test consisted in the oral administration of 6.6 g of powdered L-Arginine diluted in 250 ml of natural water.
Blood glucose, insulin, NOx, cGMP and L-Arginine were measured. Forearm blood flow (FBF) and reactive hyperaemia were measured by strain-gauge venous occlusion plethysmography. Peripheral resistance was calculates as a ratio between mean blood pressure and the FBF.
Results
L-Arginine levels were similar during the test when Biscuit +L-ARG 6.6 g and Powdered L-ARG were administered. In both cases, levels were significantly higher as compared with Biscuit alone, suggesting a complete bio-availability of L-Arginine from the biscuit. A significant increase of nitric oxide (NOx) and cGMP levels were significantly increased with Biscuit +L-ARG 6.6 g and Powdered L-ARG as compared to Biscuit. AUC NOx and cGMP were significantly increased (p<0.04vs Biscuit). Percentage incremental increase of post-ischemic blood flow significantly increased with Biscuit +L-ARG 6.6 g and Powdered L-ARG, suggesting a functional effect of L-ARG added to the food preparation. Further, at 240 minute mean arterial blood pressure and peripheral vascular resistances slightly declined with Biscuit +L-ARG 6.6 g without reaching a statistical significance. At metabolic levels, the addition of L-ARG to a biscuit decreased insulin levels in the presence of similar glycemic levels, in particular a significant decrease of AUCinsulin during the test with Biscuit +L-ARG 6.6 g in comparison to Biscuit alone was found (p<0.05).
To achieve a dose-response curve on insulin sensitivity, two further tests were performed in which 3.3 g of L-Arginine (3 biscuits) or 6.6 g of L-Arginine (6 biscuits) on 4 healthy subjects (2M/2F).
After an overnight fast, samples for blood glucose and insulin measurements were taken at 0, 30, 60, 90, 120 min. Basal blood pressure was taken in supine position after 10 min of rest, and the mean of two measurements was used as the value, after that blood pressure was also taken every 60 min until the end of the test. From the results of glucose and insulin, two indices were derived: a Modified Matsuda, (index of whole-body insulin sensitivity) and the Disposition Index (index of the product of insulin sensitivity and first phase insulin secretion). We were able to define that both indices were significantly increased with 6 Biscuits having 6.6 g of L-Arginine while intermediate values were found when 3 Biscuits (3.3 g) were eaten as compared to Biscuits without L-Arginine addition.
Conclusion:
The data of the present thesis suggest that a healthy biscuit added with L-Arginine ameliorate endothelial function and insulin sensitivity in healthy subjects and after a dose response curve, beneficial effects is achieved when three or six biscuits are administered. Further studies are needed to evaluate the beneficial effects of a chronic administration of 6 biscuits in a population of subjects with impaired glucose tolerance and Metabolic Syndrome
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
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
- …
