1,720,976 research outputs found
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
Phytochemical Characterization and Assessment of the Wound Healing Properties of Three Eurasian Propolis
No full textObjectives: The objective of this study is to evaluate the wound healing potential of Eurasian propolis by analyzing the phytochemical profile and the biological effects of three representative propolis samples. Methods: Specific colorimetric assays were used to estimate the total phenolic and flavonoid contents and the triterpenoids content. Some of the main components of Eurasian propolis (pinocembrin, pinobanksin, CAPE, chrysin and galangin) were analyzed using HPLC-DAD. Scavenging activity and total antioxidant capacity were assessed through DPPH and ORAC assays, respectively. Human keratinocyte, fibroblast, and monocytic cell lines were used for the biological in vitro analyses. The direct wound healing properties were tested through scratching assays and ELISA kits for the assessment of the production of growth factors (FGF-7, Latency Associated Peptide-LAP), while the indirect effects were evaluated through the estimation of the levels of MMP9, IL-1 beta, IL-8, and TNF-alpha using ELISA kits together with a cell-free test on the inhibition capacity on collagenases. Network Pharmacology analysis was employed to further explore possible mechanisms of the action of propolis on the healing process. Results: The analyses confirmed the high phenolic content of Eurasian propolis (142.50-211.30 mg GAE/g), dominated by flavonoids (95.50-196.80 mg Galangin Equivalents/g), and terpenes (431.50-650.00 mg beta-sitosterol Equivalents/g), while also verifying the significant antioxidant (4.9-8.9 mM/g Trolox Equivalents) and antiradical (DPPH IC50 26.1-54.4 mu g/mL) activities. The samples showed indirect wound healing properties by mitigating inflammation and remodeling (reduced IL-1 beta and MMP9) and potentially modulating the immune response (upregulated IL-8). In vitro studies confirmed these effects, demonstrating decreased MMP9 production and collagenase inhibition when cells were co-treated with propolis and a stressor. Propolis also suppressed IL-1 beta release in fibroblasts, although its impact on TNF-alpha was inconclusive. Notably, co-treatment upregulated IL-8 in monocytes, suggesting a potential immunomodulatory role. Conclusions: Eurasian propolis may not directly stimulate cell proliferation during wound healing. Its anti-inflammatory and immunomodulatory properties could indicate an indirect contribution in helping the process
Characterization of phenolic profile and antioxidant activity of the leaves of the forgotten medicinal plant Balsamita major grown in Tuscany, Italy, during the growth cycle
Full text linkBalsamita major (Asteraceae), known as costmary, is a medicinal plant rich of ethnobotanical interest in particular in Europe and Middle East, known and used since Greek and Roman times. The aim of the present study was to characterize the phenolic pattern of B. major leaves cultivated in Italy, and to measure the overall anti-radical (DPPH) and antioxidant activity (ORAC) during the growth cycle of the plant. Total polyphenols and total hydroxycinnamic acid derivatives were abundant in the leaves collected at all the growth stages, only decreasing in the flowering stage; flavonoids reached the highest content in the very early growth stage. Chlorogenic acid and 3,5-O-dicaffeoylquinic acid resulted to be the main phenolic constituents in all the extracts; their concentrations were highest at the late and early growth stages, respectively. Glycosilated flavonoids were found to be the abundant in all the extracts and quercetin resulted the main flavonoid aglycone, with the highest content in the very early growth stage. Both DPPH and ORAC tests registered good antiradical and antioxidant properties for all the extracts. Thus, B. major is worthy of further investigation, being an interesting source of antioxidant compounds, for pharmaceutical, nutraceutical and cosmetic purposes
Investigation on the Efficacy of Two Food Supplements Containing a Fixed Combination of Selected Probiotics and β-Glucans or Elderberry Extract for the Immune System: Modulation on Cytokines Expression in Human THP-1 and PBMC
No full textSeveral herbal and other natural products are used as ingredients in food supplements to strengthen immunity even if, very often, marketed products are proposed without a clear rationale or experimental evidence. In this study, we aimed to investigate the effect on human monocytes (THP-1) and on ex vivo human peripheral blood mononuclear cells (PBMC) of two formulations, one containing Bifidobacterium animalis subsp. lactis Bl-04® with β-glucans (for adults) and one containing Lactobacillus rhamnosus CRL1505 with elderberry extract (for children). We compared formulations with single ingredients, with bacterial lipopolysaccharide (LPS) and the drug pidotimod; cytokines expression level was evaluated testing different concentrations of samples at two exposure times. As expected, LPS caused a non-specific huge upregulation of cytokines expression both in THP-1 and in PBMC, whereas pidotimod mainly upregulated IL-2 in PBMC and IL-8 in THP-1. The two formulations showed a difference between a pro-inflammatory stimulus such as LPS, and also from an immunostimulant drug, such as pidotimod, as they mainly upregulated the expression of IL-6 and IL-10 in PBMC but not in THP-1, in a concentration-dependent mode. Probiotics were shown to play a major role, but β-glucans and elderberry extract exerted a synergistic activity. This work demonstrated that combining selected probiotics with other natural products having immunomodulatory properties is an interesting strategy to develop innovative formulations in the sector of food supplements
Antioxidant Effect of the Castanea sativa Mill. Leaf Extract on Oxidative Stress Induced upon Human Spermatozoa
Full text linkThis study was aimed at evaluating in vitro the effects of a 75% v/v ethanolic extract of leaves of Castanea sativa Mill. (var. Bastarda Rossa, Mount Amiata, Tuscany, Italy) on ejaculated human sperm. Total polyphenols and total flavonoids contained in the extract were determined by a colorimetric assay and HPLC-DAD. The DPPH test and electrochemistry were utilized to study the antioxidant activity of the extract. Swim-up-selected sperm from 8 healthy men were treated with the C. sativa leaf extract at different dilutions (1: 100, 1: 200, and 1: 500), and sperm motility was assessed following the WHO guidelines. Swim-up-selected spermatozoa were incubated with 100 μM H2O2 to induce lipid peroxidation (LPO) and with H2O2 and the leaf extract (1: 100, 1: 200, and 1: 500) to test the antioxidant activity of the extract. The levels of LPO were determined by measuring malondialdehyde (MDA) concentrations. The treated samples were also analyzed by transmission electron microscopy (TEM) for ultrastructural evaluation. The chemical analysis showed that one-third ca. of the polyphenols in the C. sativa extract were made up of flavonoids, with hyperoside present in high concentration. A good antioxidant activity was demonstrated by both the DPPH test and electrochemical analysis. The C. sativa leaf extract did not decrease sperm motility at all tested dilutions. Treatment with H2O2 alone caused a significant increment in MDA levels (P=0.006993), while the treatment with H2O2 plus C. sativa extract diluted to 1: 100 and 1: 200 significantly reduced MDA levels (P=0.01476 and P=0.01571, respectively), with respect to H2O2 alone. TEM analysis confirmed the protective effect of the extract on damage induced by LPO, in particular that occurring at the plasma membrane level. The C. sativa leaf extract could be used in human and farm animal protocols for gamete handling, such as techniques of assisted reproduction and cryopreservation of semen, all conditions in which oxidative stress is exacerbated
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