177,412 research outputs found
UF-5000 flow cytometer: a new technology to support microbiologists ́ interpretation of suspected urinary tract infections
No full textIn vitro cytotoxic activity of six Syzygium leaf extracts as related to their phenolic profiles: An untargeted UHPLC-QTOF-MS approach
No full textUntargeted metabolomics was used in this study to discriminate the phenolic fingerprints of six Syzygium species. This approach resulted in the annotation of 441 compounds that belong to different phenolic classes, such as flavonoids, lignans, stilbenes, tyrosols, alkylphenols, and phenolic acids. Multivariate data analysis unraveled the main differences between the studied species. S. paniculatum and S. aqueum were the richest sources in terms of phenolic compounds, cumulatively amounting to 355.3 and 266.4 mg/g dry matter, respectively. Nevertheless, S. jambos showed reduced amounts of phenolics, when compared with other species. The biological activity of Syzygium leaf extracts was assessed on MCF-7 breast adenocarcinoma and MDA-MB-231 breast cancer cell lines. Potent estrogenic activity was detected using the SRB assay on MCF-7. This activity may be ascribable to the presence of phenolic compounds miming phytoestrogens such as lignans, stilbenes, and isoflavonoids in the investigated Syzygium extracts. By examining the biological effect of Syzygium extracts against MDA-MB-231 cell lines, the Syzygium gratum leaf extract exhibited the strongest inhibition, with IC50 = 19.4 μg/mL, followed by S. paniculatum (IC50 = 50.9 μg/mL). However, the Syzygium gratum leaf extract showed a potent cytotoxic effect on normal human skin fibroblasts, HSF (IC50 = 1.24 μg/mL), assuming a nonselective cytotoxic effect. On the other hand, other studied Syzygium leaves proved as safe nutraceuticals (IC50 ≥ 100 μg/mL) on HSF cell lines. Our study suggested a possible implication of Syzygium malaccense and Syzygium aqueum leaves as potential estrogenic candidates in relation to their health-promoting phenolic constituents
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
PREOPERATIVE INTRA-ORAL ULTRASOUND IN THE EVALUATION OF EARLY ORAL SQUAMOUS CELL-CARCINOMA: PROSPECTIVE STUDY
No full textPreoperative evaluation of depth of invasion can predict occult metastasis in cervical lymph nodes of OSCC patients and target patients who need neck dissection but there is no standard modality to determine this parameter preoperatively. The primary aim of this study was to evaluate the accuracy of a preoperative measurement of depth of invasion using Ultrasonography and correlate the values obtained with histologically determined DOI measurements. Specifically, we used a very small and thin Ultrasound probe, like a toothbrush, that help directly reach the oral lesions. We enrolled 32 biopsy proven primary T1/T2/T3 OSCC patients who underwent pre-operative intraoral ultrasound for the evaluation of the tumor diameter and depth of invasion. Ultrasound sensitivity, specificity and accuracy in the assessment of the infiltration of the lamina propria, the correlation between Ultrasound and histological depth of invasion and the correlation between diameter of the lesion and depth of invasion assessed with Ultrasound were evaluated. Ultrasound sensitivity and specificity in the assessment of the infiltration of the lamina propria were respectively 93.3% and 100%. A significant correlation was found between the measurement of US-obtained and histologically obtained depth of invasion (r = 0.907; p < .0001; 95% CI, 0.816 to 0.954). A medium correlation was found between diameter of the lesion and depth of invasion assessed with Ultrasound (r = 0.591; p < .0001; 95% CI, 0.306 to 0.779). According to our results, intraoral Ultrasound is very accurate in determining tumor depth of invasion in OSCC patients and represents a useful, cost-effective and promisig tool to insert in the diagnostic flow-chart of OSCC
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Application of metabolomics to decipher the role of bioactive compounds in plant and animal foods
No full textThe consumption of foods characterized by a wide bioactive-compound profile has been associated with improved health status and reduced risk of developing diseases. Owing to the complexity of food production (e.g. crops and farmed animals), processing (e.g. fermentation), and shelf life (e.g. lipid or protein oxidation), a more comprehensive and holistic analysis is necessary to investigate the intricate metabolic pathways and metabolites involved with or displaying a biological activity. Accordingly, untargeted metabolomics analysis can provide crucial knowledge to support the selection of key metabolites and metabolic pathways to produce foods from animals and crops with a functional value. This short review aims to provide an overview of the applications of metabolomic analysis to screen bioactive compounds in both animal- and plant-based foods
Metalation of 2-chloromethyl-2-oxazolines: Synthesis of 1,2,3-tris(oxazolinyl)cyclopropanes and derivatives
No full text2-Chloromethyl-2-oxazoline converts cleanly into trans-1,2,3-tris(oxazolinyl)cyclopropane upon treatment with strong bases such as LDA or KN(SiMe3)2. Deprotonation of the above cyclopropane followed by the addition of electrophiles allows the preparation of more functionalized tris-(oxazolinyl)cyclopropanes
Determination of polyphenols using liquid chromatography–tandem mass spectrometry technique (LC–MS/MS): A review
No full textIn recent years, the consumption of polyphenols has been increasing, largely due to its beneficial effects on health. They are present in a wide variety of foods, but their extraction and characterization are complicated since they are mostly in complex matrices. For this reason, the use of selective, sensitive, and versatile analytical techniques such as liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS) is necessary. In this review, the most relevant studies of the last years regarding the analysis of polyphenols in different matrices by comprehensive LC– MS/MS are discussed. Relevant steps such as extraction, sample purification, and chromatographic analysis methods are emphasized. In particular, the following methodological aspects are discussed: (a) the proper selection of the extraction technique, (b) the extraction and elution solvents, (c) the purification step, (d) the selection of both stationary and mobile phases for the chromatographic separation of compounds, and (e) the different conditions for mass spectrometry. Overall, this review presents the data from the most recent studies, in a comprehensive way, thus providing and simplifying the information of the great variety of works that exist in the literature on this wide topic
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