1,721,102 research outputs found
Studio sul contenuto in lipidi, polifenoli e carotenoidi in foglie di vite sottoposte a taglio meccanico.
Full text linkProduction of conjugated linoleic acid (CLA): effect of inulin on microbial composition and CLA concentration in a human intestinal model
No full textConjugated linoleic acids (CLAs) show a number of putative health-promoting activities including anti-carcinogenic, anti-adipogenic, anti-diabetogenic, anti-inflammatory and antioxidant actions. CLAs are naturally produced by ruminal bacteria and several studies demonstrate that various lactobacilli and bifidobacteria are also able to produce CLAs in vitro from linoleic acid (LA). However, the ability of the human gut microbiota to produce CLA is less extensively studied. Our hypothesis is that the human gut microbiota is able to convert LA to CLA, and that the readily fermentable fiber inulin would positively modulate the growth of CLA-producing bacteria and, consequently increase the CLA content in the intestine. The capability of the faecal microbiota from five healthy donors to produce CLA was tested in anaerobic batch cultures for 48 hours at pH 5.5 and 6.5. Test treatments were linoleic acid (LA; 1 mg/mL) + bovine serum albumin (BSA; 0.2 mg/mL), and LA (1 mg/mL) + BSA (0.2 mg/mL) + inulin (1%, w/v) compared to a control BSA (0.2 mg/mL) fermentation. The microbial composition was analyzed 0, 24 and 48 hours after starting the fermentation by 16S rRNA gene Illumina MiSeq sequencing (V3-V4 region). CLAs were quantified by Ultra performance liquid chromatography - tandem mass spectrometer (UPLC-MS/MS) and bi-dimensional gas chromatography (GC x GC). The inclusion of LA+BSA+inulin at pH 5.5 significantly increased the relative abundance of Collinsella aerofaciens (p<0.05), and tended to increase the relative abundance of bifidobacteria. LA+BSA+inulin at both pH 5.5 and 6.5 reduced the relative abundance of Parabacteroides, Bilophila, Clostridia and Enterobacteriaceae (p<0.05). The concentration of CLA, in particular the isomer cis9,trans11 C18:2, was significantly higher in the LA+BSA+inulin group at pH 5.5 after 24 and 48 hours fermentation. The data show that the treatment LA+BSA+inulin at pH 5.5 induce substantial changes in microbiota composition, including bifidogenesis and CLA production in a human intestinal microbiota model. The changes of relative abundance detected are consistent with changes in gut bacteria previously linked to human health. Collinsella aerofaciens has been reported for reducing bloating, in particular in subjects suffering from irritable bowel syndrome, while Clostridia, Bilophila and Enterobacteriaceae causes human infections. In addition, the increase of bifidobacteria and LAB, which have previously been shown in vitro to produce CLA, may also be involved in CLA production under simulated cecal microbiome. These preclinical observations warrant confirmation in suitably designed animal and human mechanistic studies
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
A Deep Analytical Investigation of the Aroma Chemistry of Incrocio Bruni 54 and Its Differentiation from Italian White Varieties
Full text linkIncrocio Bruni 54 is a little-known white grape variety developed in the Marche region (Italy) from a cross between Verdicchio and Sauvignon Blanc to combine aromatic freshness with structure. In light of the growing interest in minor and autochthonous cultivars, this study provides the first comprehensive chemical characterization of the aroma profile of Incrocio Bruni 54 wines. Seventeen commercial wines were analyzed for varietal compounds, such as terpenes, norisoprenoids, volatile thiols, methyl salicylate and its glycosides, and fermentative compounds, including esters, alcohols, acids, phenols, aldehydes, and ketones, using GC-MS/MS and LC-MS/MS. Odor activity value (OAV) calculations revealed an aroma profile dominated by ethyl esters, such as ethyl caproate and isopentyl acetate, β-damascenone, 4-vinylguaiacol, TDN, and the volatile thiols 3MH and 4MMP, imparting fruity, floral, spicy, and tropical notes. Comparison with datasets of 246 Italian monovarietal white wines and related sub-datasets composed of Verdicchio and Lugana showed significantly higher concentrations of 3MH and free methyl salicylate in Incrocio Bruni 54, but markedly lower levels of glycosylated methyl salicylate forms, suggesting a greater expression of this odorant in young wines balanced by a lower potential over aging. These findings highlight the distinctive aromatic fingerprint of Incrocio Bruni 54, combining parental traits with unique sensory potential, and support its knowledge and valorization in wine production
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
Methyl salicylate glycosides in some Italian varietal wines
Full text linkGlycosides are ubiquitous plant secondary metabolites consisting of a non-sugar component, called an aglycone, attached to one or more sugars. One of the most interesting aglycones, found in grapes and in wine, is methyl salicylate (MeSA). MeSA is an organic ester naturally produced by many species of plants, particularly wintergreens. It is synthesised from salicylic acid, a phytohormone that contributes to plant pathogen defence and some of MeSA glycosides are expected to substitute aspirin due to their long-term effects and fewer side effects. To date nine different methyl salicylate glycosides from plants have been reported (Mao et al., 2014). These methyl salicylate glycosides are mainly spread over the genera Gaultheria, Camellia, Polygala, Filipendula and Passiflora. From the sensorial point of view, methyl salicylate has a balsamic-sweet odour that is known as “Wintergreen oil”.
Methyl salicylate was found in V. riparia grapes by (Schreier & Paroschy, 1980) and in V. vinifera sp. (Cabaroglu et al., 1997; Versini, Moser, & Carlin, 2005) and in the Frontenac interspecific hybrid (Mansfield, Schirle-Keller, & Reineccius, 2011). We found that the methyl salicylate glycosides content in Verdicchio wines and in some genetically related varieties (Trebbiano di Soave and Trebbiano di Lugana) was very high. In order to understand which glycosides were present in wine, the methanolic extract of Verdicchio wine after SPE was injected into a UPLC-Q-TOF-HDMS, extract of different plants particularly rich in such glycosides, were also injected. We confirmed, using pure standards, the existence in wine of two glycosides: a MeSA 2-O--D-glucoside and a MeSA 2-O--D-xylopyranosyl (1-6) -D-glucopyranoside (gaultherin), we also tentatively identified, for the first time in wine, other diglycosides: MeSA 2-O--L-arabinopyranosyl(1-6)--D-glucopyranoside (violutoside) and MeSA 2-O--D-apiofuranosyl(1-6)--D-glucopyranoside (canthoside A), a MeSA 2-O--D-glucopyranosyl(1-6)-O--D-glucopyranoside (gentiobioside) and a MeSA-2-O--L-rhamnopyranosyl(1-6)--D-glucopyranoside (rutinoside). Some of this glycosides have been isolated from Gaultheria leaves and NMR analysis are underway to provide detail information about the structure In order to understand if these glycosydes are a “peculiarity” of Verdicchio wines and its homologous, 40 different white wines were analysed. The range of concentration for the sum of this 6 MeSA glycosides was very variable. 0 to 300 g/L. As the olfactory threshold of this compound is between 50 and 100 g/L, it is suggested that methyl salicylate contributes to the balsamic scent in old Verdicchio wine
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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