1,720,972 research outputs found
Total antioxidant capacity as a tool to assess redox status: critical view and experimental data
No full textThe measure of antioxidant capacity (AC) considers the cumulative action of all the antioxidants present in plasma and body fluids, thus providing an integrated parameter rather than the simple sum of measurable antioxidants. The capacity of known and unknown antioxidants and their synergistic interaction is therefore assessed, thus giving an insight into the delicate balance in vivo between oxidants and antioxidants. Measuring plasma AC may help in the evaluation of physiological, environmental, and nutritional factors of the redox status in humans. Determining plasma AC may help to identify conditions affecting oxidative status in vivo (e.g., exposure to reactive oxygen species and antioxidant supplementation). Moreover, changes in the plasma AC after supplementation with galenic antioxidants or with antioxidant-rich foods may provide information on the absorption and bioavailability of nutritional compounds. Consequently, this review discusses the rationale, interpretation, confounding factors, measurement limits, and human applications of the measure of plasma AC
Olive polyphenol effects in a mouse model of chronic ethanol addiction
Full text linkObjectives Alcohol addiction elicits oxidative imbalance and it is well known that polyphenols possess antioxidant properties. We investigated whether or not polyphenols could confer a protective potential against alcohol-induced oxidative stress. Methods We administered (per os) for two months 20 mg/kg of olive polyphenols containing mostly hydroxytyrosol in alcoholic adult male mice. Hydroxytyrosol metabolites as hydroxytyrosol sulfate 1 and hydroxytyrosol sulfate 2 were found in the serum of mice administered with polyphenols with the highest amount in animals treated with both polyphenols and alcohol. Oxidative stress was evaluated by FORT (free oxygen radical test) and FORD (free oxygen radical defense) tests. Results Alcoholic mice showed a worse oxidative status than nonalcoholic mice (higher FORT and lower FORD) but polyphenol supplementation partially counteracted the alcohol pro-oxidant effects, as evidenced by FORT. Conclusions A better understanding of the antioxidant protection provided by polyphenols might be of primary interest for drug discovery and dietary-based prevention of the damage associated with chronic alcohol abus
Improvement of the nutraceutical quality of broccoli sprouts by elicitation
Full text linkEpidemiological studies show an inverse association between Brassica consumption and chronic diseases. Phytochemicals are thought to be beneficial for human health and therefore responsible for this protective effect. Increasing their levels into Brassica food is considered an expedient nutritional strategy that can be achieved through the manipulation of growth conditions by elicitors. In this work we systematically evaluated the influence of treatment with different elicitors (sucrose, mannitol, NaCl, 1-aminocyclopropane-l-carboxylic acid, salicylic acid and methyl jasmonate) on the phytochemical composition of broccoli sprouts. The content of total and single glucosinolates, total phenolic compounds, total flavonoids, total anthocyanins, vitamin C and E and β-carotene was assessed.
The exposure to different elicitors produced concentration- and elicitor-dependent specific changes in the content of all the phytochemicals considered. Sucrose, identified as the most effective elicitor by principal component analysis, induced a significant increase of total and specific glucosinolates, vitamin C, total anthocyanins and polyphenols. Sucrose is likely to represent an effective tool to increase the nutritional value of broccoli sprouts
Nondestructive analysis of phytochemicals present in fruits and vegetables by Photoacoustic techniques
No full textFruits and vegetable have long been regarded as having considerable beneficial effects on health, due in part, to the presence of bioactive compounds or phytochemicals. Their amount and composition in plant foods is strongly dependent on a number of factors as genotype, ripening, environmental conditions, climate, cultivation practices, harvesting modalities and storage methods. Moreover, phytochemicals are responsible for the organoleptic characteristics of foods such as colour, aroma and taste. In the human organism, these bioactive compounds are involved in several cellular processes. For example, they are able to neutralize or reduce the oxidative stress, to interact and modulate multienzymatic systems, to inhibit platelet aggregation, to counteract the carcinogenesis, to reduce the formation of inflammatory molecules through different mechanisms. Therefore, the daily and continuous introduction of these substances is of particular importance for human health.
All these properties confer to phytochemicals an important role as biomarkers of nutritional, healthy and commercial quality. Nowadays, both the food industry and the agricultural sector need of rapid screening tools that make it possible the quality control along the whole chain of production (from farm to finished product). In this respect is desirable a non-destructive analytical approach, which allows to correlate the information obtained from direct analysis of bioactive compounds content in plant foods with the stadium of ripeness, freshness, shelf life of products.
In the recent years, the Photoacusitc (PA) and Photothermal (PT) techniques have been applied for quantifying phytochemicals present in fruits and vegetables. In particular, these techniques have allowed the direct quantitative analysis of carotenoids (α- and β-carotene, lycopene) and flavonoids (mainly anthocyanins) in fresh produce products such as tomatoes, carrots, brassicaceae, oranges, cherries, apricots, grapes, wine, etc, with little or no manipulation of the sample.
In this context we obtained preliminary data from PA signals measurements in peel of apple fruits belonging to two different varieties: Golden Delicious apple and Pink Lady apple. The results revealed that PA signals were in agreement with different apple peel colours due to the different distribution and content of chlorophylls (a and b), carotenoids and anthocyanins in apple peel.Fruits and vegetable have long been regarded as having considerable beneficial effects on health, due in part, to the presence of bioactive compounds or phytochemicals. Their amount and composition in plant foods is strongly dependent on a number of factors as genotype, ripening, environmental conditions, climate, cultivation practices, harvesting modalities and storage methods. Moreover, phytochemicals are responsible for the organoleptic characteristics of foods such as colour, aroma and taste. In the human organism, these bioactive compounds are involved in several cellular processes. For example, they are able to neutralize or reduce the oxidative stress, to interact and modulate multienzymatic systems, to inhibit platelet aggregation, to counteract the carcinogenesis, to reduce the formation of inflammatory molecules through different mechanisms. Therefore, the daily and continuous introduction of these substances is of particular importance for human health.
All these properties confer to phytochemicals an important role as biomarkers of nutritional, healthy and commercial quality. Nowadays, both the food industry and the agricultural sector need of rapid screening tools that make it possible the quality control along the whole chain of production (from farm to finished product). In this respect is desirable a non-destructive analytical approach, which allows to correlate the information obtained from direct analysis of bioactive compounds content in plant foods with the stadium of ripeness, freshness, shelf life of products.
In the recent years, the Photoacusitc (PA) and Photothermal (PT) techniques have been applied for quantifying phytochemicals present in fruits and vegetables. In particular, these techniques have allowed the direct quantitative analysis of carotenoids (α- and β-carotene, lycopene) and flavonoids (mainly anthocyanins) in fresh produce products such as tomatoes, carrots, brassicaceae, oranges, cherries, apricots, grapes, wine, etc, with little or no manipulation of the sample.
In this context we obtained preliminary data from PA signals measurements in peel of apple fruits belonging to two different varieties: Golden Delicious apple and Pink Lady apple. The results revealed that PA signals were in agreement with different apple peel colours due to the different distribution and content of chlorophylls (a and b), carotenoids and anthocyanins in apple peel
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
Buckwheat hull extracts inhibit Aspergillus flavus growth and AFB1 biosynthesis
Full text linkFungal contamination poses at risk the whole food production chain-from farm to fork-with potential negative impact on human health. So far, the insurgence of pathogens has been restrained by the use of chemical compounds, whose residues have gradually accumulated determining toxic effects in the environment. Modern innovative techniques imply the use of natural and eco-sustainable bioactive plant molecules as pathogens and pests-control agents. These may be profitably recovered in large amounts at the end of industrial milling processes. This is the case of the non-digestible hull of common buckwheat (Fagopyrum esculentum Moench), a natural source of polyphenols, tocopherols, phytosterols and fatty acids. We extract these compounds from the hull of buckwheat; apply them to Aspergillus flavus-aflatoxin producer-under in vitro conditions, checking their ability to inhibit fungal growth and aflatoxin biosynthesis. Moreover, a solvent free method implying the adoption of supercritical CO2 as solvent was set up to extract lipophilic molecules from the buckwheat’ hulls. Positive results in controlling fungal growth and aflatoxin biosynthesis let infer that the extracts could be further tested also under in vivo conditions
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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