1,720,999 research outputs found
In vitro ability of essential oils and surfactants to enhance the antimicrobial activity of preservative agents against Pseudomonas aeruginosa and Staphylococcus aureus
No full textThe aim of this study is to evaluate possible
synergistic antimicrobial interactions between common
cosmetic preservatives and selected essential oils or surfactants.
The antimicrobial efficacy of six essential oils,
three surfactants and five preservatives against Pseudomonas
aeruginosa ATCC 9027 and Staphylococcus aureus
ATCC 43387 was assessed by a broth micro-dilution assay.
MICs for individual and combined antimicrobials were
determined and then transformed to fractional inhibitory
concentration (FIC) indexes. All essential oils exhibited
antibacterial activity; among surfactants, bacteria resulted
most susceptible to the cationic agent. Synergy was
observed when essential oils of eucalyptus and mint were
combined with methylparaben against P. aeruginosa, while
essential oils of mint, oregano and sage combined with
propylparaben and imidazolidinyl urea acted against S.
aureus. Many binary mixtures of preservatives and surfactants
produced synergistic activity with the most effective
interactions involving the cationic and amphoteric
compounds under study. FIC indexes demonstrated synergistic
effects when preservatives were combined with
either essential oils or surfactants against both bacterial
strains. These results highlight the potential usefulness of
essential oils and surfactants to enhance the activities of
conventional biocides. This kind of study should contribute
to the selection and optimization of preservative systems
for cosmetic preparations
Microbial study of cosmetic products during their use by consumers: health risk and efficacy of preservative systems
No full textTo evaluate the microbial contamination of 91 cosmetics (23 o/w emulsions,
47 tensiolytes, 21 aqueous pastes) in three different states of use (intact,
in-use, ending product) and the protection efficacy of the preservative systems
most frequently used in the analysed cosmetic formulations.
Methods and Results: Total bacterial count, isolation and identification of
pathogenic isolates were performed on the collected cosmetics. About 10Æ6% of
tensiolytes (13Æ5% bath foam, 6Æ7% shampoo, 10% liquid soaps) were contaminated
by Staphylococcus warneri, Staphylococcus epidermidis and Pseudomonas
putida. The efficacy of the preservative systems of two cosmetic products, tested
against standard micro-organisms (Staphylococcus aureus ATCC 4338 and Pseudomonas
aeruginosa ATCC 9027) and two isolates from cosmetics in this study
(S. epidermidis and P. putida), satisfied the Cosmetics, Toiletries, and Fragrance
Association and Official Italian Pharmacopeia criteria, while only one tested
cosmetic respected the Rapid Challenge Test criterion.
Conclusions: Contaminated cosmetic products are relatively uncommon, but
some products, unable to suppress the growth of several micro-organisms, represent
a potential health hazard.
Significance and Impact of the Study: The challenge test may be performed
not only during the preparation of the preservative system in the intact cosmetics,
but also be used to evaluate the protection efficacy during their use
Epidemiologia dell'influenza in allevamenti di suini dell'Italia Settentrionale nell'inverno 1976
No full textAntibiotic resistance of Campylobacter spp isolated from chickens and humans in central Italy
No full textCampylobacter jejuni and Campylobacter coli strains, isolated from slaughtered chickens and human feces, were examined for their susceptibility to six antibiotics (ampicillin, cefotaxime, erythromycin, levofloxacin, nalidixic acid and trimethoprim) by broth microdilution, for minimum inhibitory concentration determination, and disc diffusion assays. For the 32 C. jejuni isolates, the highest levels of resistance were to trimethoprim (65.6% of the isolates by broth microdilution and 62.5% by disc diffusion) and cefotaxime (62.5% by both methods). Comparable levels of resistance to these antibiotics were found in the 24 C. coli isolates. Statistically significant differences were found between all C. coli isolates for cefotaxime (P = 0.0043) using disc diffusion. A high proportion of C. jejuni isolates show resistance to nalidixic acid using both the broth microdilution (59.4%) and disc diffusion (56.2%) methods. C. coli strains were resistant to this antibiotic showing proportions of 75% when tested by broth microdilution and 70.8% by disc diffusion. Multidrug resistance was detected in 21.8% and 62.5% of C. jejuni and C. coli strains, respectively, by broth microdilution test and in 28.1% and 75% of C. jejuni and C. coli strains by disc diffusion method. None of the isolates showed the same pattern of multidrug resistance. © 2010 Wiley Periodicals, Inc..
polymorphic DNA (RAPD) analysis and unweighted pairgroup method with
arithmetic averages (UPGMA) cluster analysis. Our findings revealed an high
diversity of the autochthonous bacterial populationinvestigated, both at species
and strain level
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
- …
