1,720,958 research outputs found
Antibacterial and Anti-Biofilm Activities of Acetone Extracts of Usnea sp. against Mixed Cultures of Bacteria from Soak Liquor Samples and Tank Surfaces
No full textLong-term or improper use of antibacterial agents utilized in the soaking process has led to the resistance of some bacteria in the leather industry. New agents may be the solution to combat these antibacterial resistant bacteria in the soaking process. As a natural resource, lichens are known to have many biological activities. In previous studies, we demonstrated that the acetone extracts of several lichen species including Usnea sp. may have potential antibacterial and anti-biofilm properties against some Bacillus species, which were isolated from different soak liquor samples. In the present study, it was questioned whether the same bioactivities of acetone extracts of Usnea sp. can be seen in the mixed cultures of tank surface samples and pre-and main soak liquor samples, which were obtained from different tanneries. Although the extracts did not show noteworthy antibacterial effect against one of the tank surface samples (inhibition ratios; 6.5-16.22%), inhibition percentages were detected as 69.32 and 46.33 at the concentrations of 240 and 120 mu g/mL for the other tank surface sample. The anti-biofilm potential of the extracts was tested on the sample where the antibacterial activity of the extracts was not observed. One of the mixed culture of samples from the tank surface could not be inhibited by the extracts in terms of bacterial growth. However, the extracts were tested on this biofilm-forming sample and detected more than 50% inhibition. Furthermore, the extracts inhibited the growth of the mixed culture of bacteria from pre-soak liquor by the percentages of 78.96, 61.5, 51.3, 45.1, and 33.4 at the concentrations of 240, 120, 60, 30 and 15 mu g/mL, respectively. On the other hand, the same antibacterial efficacy could not be observed in the other mixed culture from presoak liquor sample obtained from a different tannery whereas this sample formed a biofilm structure. The mixed culture of samples from the main soaking process was inhibited by the extracts at the inhibition percentages of 62.13-78.17 at the concentrations of 240- 30 mu g/mL. Similar results were also obtained for the other sample (64.6-76.5%) from main soak liquor sample obtained from a different tannery. In conclusion, lichen extracts may have potential antibacterial and anti-biofilm properties against the mixed culture of bacteria from tank surface, pre-and main soak liquor samples and maybe alternatively utilized in the leather industry
Antibacterial Potential of Six Lichen Species against Enterococcus durans from Leather Industry Evaluation of acetone extracts obtained from several lichen species as alternative natural antibacterial agents
No full textAntibacterial resistant bacteria are a significant problem in the hide or skin soaking process due to their destructive properties on finished leather. Lichens may be a solution to overcome this resistance problem. Enterococcus durans (99.86%) was isolated from soak liquor samples. For screening of possible antibacterial effects of lichen acetone extracts, six lichen species (Hypogymnia tubulosa, H. physodes, Evernia divaricata, Pseudevernia furfuracea, Parmelia sulcata and Usnea sp.) were examined by nine-fold dilution against E. durans. H. tubulosa, H. physodes and E. divaricata extracts showed antibacterial effects at the concentrations of 240 mu g ml(-1), 120 mu g ml(-1) and 60 mu g ml(-1) whereas the extracts of P. furfuracea had an antibacterial effect at 240 mu g ml(-1) and 120 mu g ml(-1). On the other hand, P. sulcata had no antibacterial effect. The most successful lichen extract was determined to be Usnea sp. at the concentrations of 240 mu g ml(-1), 120 mu g ml(-1), 60 mu g ml(-1), 30 mu g ml(-1) and 15 mu g ml(-1). In conclusion, lichen extracts seem to have potential antibacterial efficacies against E. durans
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Efficacy of Usnea sp. Extracts in Preventing Biofilm Formation by Bacillus Species Isolated from Soaking Liquor Samples
No full textBacteria forms biofilm to be resistant to antibacterial agents and other unfavorable environment as compared to planktonic bacterial cells. Due to resistance of bacterial biofilms to commonly used antimicrobial agents and adverse effects of these biofilms in different industries, potential natural compounds which can inhibit bacterial biofilms have attracted more attention in recent years. Lichens are known to have unique secondary metabolites with various biological activities including anti-biofilm properties. Therefore, Bacillus toyonensis, Bacillus mojavensis, Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus velezensis, Bacillus cereus, and Bacillus licheniformis, isolated from soak liquor samples in the previous study, were tested for their ability to form biofilm in this study. Biofilm-forming Bacillus species were detected as B. subtilis, B. amyloliquefaciens, and B. velezensis. The anti-biofilm effect of the acetone extracts of Usnea sp. was evaluated at various concentrations against these biofilm-forming isolates. The anti-biofilm effect of acetone extracts of Usnea sp. against B. subtilis and B. amyloliquefaciens was observed at the concentration of 5 mu g/mL by inhibition ratios of 62.75% and 72.72%, respectively. In addition, biofilm formation of B. velezensis was inhibited by the treatment with 1.25 mu g/mL extracts at a 62.69% inhibition rate. Biofilm formations of B. amyloliquefaciens and B. velezensis were also suppressed by the extracts at varying percentages of inhibition ranging between 10.11-43.69% and 21.25-46.35%, respectively. This study may provide an alternative approach to overcome the biofilm formation and bacterial resistance to the antibacterial agents in the leather industry
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
Get PDFWe 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
- …
