1,720,963 research outputs found
The antibacterial activity of Libyan honey against gram negative bacilli: Potential treatment agent for infectious diseases?
No full textAims: Honey has is a rich source of many compounds that exhibit anti-microbial, anti-inflammatory and pro-angiogenic properties. The emergence of antibiotic resistance in a wide variety of bacterial pathogens has generated renewed interest in natural antimicrobials. The aim of the present study was to assess the antibacterial activity of Libyan honey in vitro.
Methodology: The antibacterial activities of selected Libyan origin honey including Libyan Spring, AL-Sader, Thyme and Al-Hanone (at 25%, 50%, 75% and 100 % (w/v)) were tested against Yersinia enterocolitica, Escherichia coli and Proteus mirabilis using agar well-diffusion assay. The measurement of exponential bacterial growth curves was used to determine the effects on the microbial growth pattern spectrophotometrically at 600 nm. In addition, plate count methods were used to enumerate the effects of honey on the viable bacterial count.
Results and Discussion: Honey progressively inhibited bacterial growth at higher concentrations. This effect was variable depending on the honey type. For example, Al Sader honey showed the highest inhibition zones 21.3 mm ±0.8 against P. mirabilis followed by Thyme (21 mm ±0.5) and spring (20 mm ±0.5). Al-Hanone honey only exhibited effects against E. coli (14 mm ±0.5 and 8 mm ±0.4 at 100% w/v and 75% w/v, respectively). The Al Sader, spring and Thyme honey significantly reduced the Yersinia enterocolitica bacteria growth curve (p<0.05). All tested honey significant reduced E. coli growth from 5hrs compared to the control samples (p<0.05).
Conclusion: All honey tested showed inhibition of bacterial growth. Concentrated honeys were more effective against Yersinia enterocolitica, Escherichia coli and Proteus mirabilis. The efficacy of different types of honey was dependent on the honey concentration and origin
Diluted honey inhibits biofilm formation: potential application in urinary catheter management?
No full textAims
Biofilms are ubiquitous and when mature have a complex structure of microcolonies in an extracellular polysaccharide and extracellular DNA matrix. Indwelling medical devices harbour biofilms which have been shown to cause infections and act as reservoirs for pathogens. Urinary catheters are often in place for considerable periods of time and are susceptible to both encrustation and biofilm formation. Strategies for minimising biofilm occurrence underpin an active research area in biomedicine. Manuka honey has, inter alia, well-established antibacterial properties. This study aims to assess the influence of honey on early biofilm formation in an established in vitro model.
Methods
An established model of early biofilm formation using static bacterial cultures in vinyl 96-well plates was used to grow Escherichia coli, strain ATC 25922 and Proteus mirabilis, strain 7002. Planktonic cells were removed and the residual biofilm was stained with crystal violet, which were subsequently eluted and quantified spectrophotometrically. Manuka honey (Unique Manuka Factor 15+) was added either with the bacteria or up to 72 hours after.
Results
Biofilms in this model was developed over 3 days, after which growth stalled. Mixed (1:1) cultures of E. coli and P. mirabilis grew slower than monocultures. In mixed cultures, honey gave a dose-dependent reduction in biofilm formation (between 3.3 and 16.7%w/v). At 72 hours, all concentrations inhibited maximally (p<0.001). Application of honey to cultures after 24 and 48 hours also reduced the adherent bacterial biomass (p<0.05–p<0.01).
Conclusion
Manuka honey at dilutions as low as 3.3% w/v in some protocols and at 10% or above in all protocols tested significantly inhibits bacterial attachment to a vinyl substrate and reduces further early biofilm development. No augmentation of growth over untreated controls was observed in any experiment
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
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