1,720,991 research outputs found
Evaluation of the effectiveness of N-Acetylcysteine (NAC) and N-acetylcysteine-cyclodextrins Multi-Composite in Pseudomonas aeruginosa biofilm formation
No full textPseudomonas aeruginosa is a gram-negative bacillus involved in biofilm production in several lung diseases. In this study, the in vitro anti-biofilm effect of both N-acetylcysteine (NAC)-a well-known antioxidant compound and GSH prodrug-and NACESOLTM-a new multicomposite based on NAC, resveratrol, and cyclodextrins-was investigated by evaluation of reduction of bacterial colonies growth. Physico-chemical analysis of NACESOLTM was performed by differential scanning calorimetry (DSC), Fourier-transform infrared (FT-IR) spectroscopy, and X-ray powder diffraction (XRPD) techniques. The anti-biofilm activity of NAC and NACESOLTM, expressed as percentage of biofilm reduction, revealed an increased biological activity of multicomposite at low concentrations. Furthermore, the NAC activity against P. aeruginosa biofilm was also studied using scanning electron microscopy (SEM) joined to the energy dispersive spectrometry (EDS) technique, which is able to evaluate the reduction of sulfur element on biofilm surface. The use of SEM-EDS highlights the biofilm amount decrease with increasing NAC concentration. This work permitted us to highlight the minimum concentration of NAC able to interact in the P. aeruginosa biofilm formation process and the promising use of a new composite based on NAC and cyclodextrins
A New In Vitro Model to Evaluate Anti-Adhesive Effect against Fungal Nail Infections
No full textNail fungal infection is often mistakenly considered a minor issue or a purely esthetic problem that is not worth solving. However, onychomycosis has been demonstrated to have a negative impact on a patient’s social life. Therefore, given the poor efficacy of various therapy types, there is strong interest in exploring new methods for evaluating antifungal treatments. As such, the
aim of this work was to develop a new protocol, using bovine hoof membranes as a model of the human nail to evaluate the capability of a product claiming to prevent fungal adhesion, which is the first step of the infection. In this work, two specific and representative fungal strains, Trichophyton rubrum and Candida albicans, were used. In order to evaluate the possible protective activity of a product against fungal contamination of the nail plate, it was first necessary to test the affinity of
the hoof membranes to be contaminated by the fungi. Then, a pharmaceutical product and a base coat were tested as a positive and negative control, respectively, by introducing the membranes (anti-fungal, basic or no treatment and single vs. multiple treatments) into the fungal suspensions for three different contact times (15 min, 5 h and 24 h). The results showed that the more significant antiadhesive effect (AE) was obtained against Trichophyton rubrum than against Candida albicans.
Furthermore, taking into account the results obtained at all testing times, 5 h appeared to be the best time for testing the antiadhesive activity. The results obtained after three treatments with drugs and on washed membranes, in comparison to one single application of antifungal product (AP), demonstrated clearly that the drug was able to penetrate deeper into the membranes to exert itself, even after washing and also after only 15 min of contact. Thus, hoof membrane has been shown to be a valuable in vitro model for this kind of product assessment
Application of Airborne Microorganism Indexes in Offices, Gyms, and Libraries
No full textThe determination of microbiological air quality in sporting and working environments requires the quantification of airborne microbial contamination. The number and types of microorganisms, detected in a specific site, offer a useful index for air quality valuation. An assessment of contamination levels was carried out using three evaluation indices for microbiological pollution: the global index of microbiological contamination per cubic meter (GIMC/m3), the index of mesophilic bacterial contamination (IMC), and the amplification index (AI). These indices have the advantage of considering several concomitant factors in the formation of a microbial aerosol. They may also detect the malfunction of an air treatment system due to the increase of microbes in aeraulic ducts, or inside a building compared to the outdoor environment. In addition, they highlight the low efficiency of a ventilation system due to the excessive number of people inside a building or to insufficient air renewal. This study quantified the levels of microorganisms present in the air in different places such as offices, gyms, and libraries. The air contamination was always higher in gyms that in the other places. All examined environments are in Northern Italy
Microstructured lipid carriers (MLC) based on N-acetylcysteine and chitosan preventing Pseudomonas Aeruginosa biofilm
No full textThe aim of this work was the development of microstructured lipid carriers (MLC) based on chitosan (CH) and containing N-acetylcysteine (NAC), a mucolytic and antioxidant agent, to inhibit the formation of Pseudomonas aeruginosa biofilm. MLC were prepared using the high shear homogenization technique. The MLC were characterized for morphology, particle size, Z potential, encapsulation efficiency and drug release. The antioxidant properties of NAC-loaded microstructured carriers were evaluated through an in vitro spectrophotometer assay. Finally, the activity of NAC-CH-MLC on biofilm production by Pseudomonas aeruginosa was also evaluated. Results obtained from this study highlighted that the use of chitosan into the inner aqueous phase permitted to obtain microstructured particles with a narrow size range and with good encapsulation efficiency. NAC-loaded MLC showed higher antioxidant activity than the free molecule, demonstrating how encapsulation increases the antioxidant effect of the molecule. Furthermore, the reduction of biofilm growth resulted extremely high with MLC being 64.74% ± 6.2 and 83.74% ± 9.95, respectively, at 0.5 mg/mL and 2 mg/mL. In conclusion, this work represents a favorable technological strategy against diseases in which bacterial biofilm is relevant, such as cystic fibrosis
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
Anti- and pro-oxidant activity of Cichorium genus vegetables and effect of thermal treatment in biological systems
No full textThe antiradical activity of water soluble components in six vegetables belonging to the Cichorium genus, i.e., three cultivars of red
intybus species var. silvestre (Treviso, Chioggia, Verona red chicories), a white intybus species var. foliosum (Belgian chicory), and
two vegetables of the endivia species var. latifolium (escarole chicory) and var. crispum (‘‘crispa’’ chicory), were studied using two
biological systems consisting of: (1) microsome membrane rat hepatocyties in which oxidative damage was induced by CCl4; (2)
gram-positive bacterium, Staphylococcus aureus cultures, subjected to damage with cumene hydroperoxyde. The obtained results
show that in both systems the red vegetables possess the strongest antioxidant properties and contain different antioxidant compounds
whether at a low or high molecular weight, but only those of high molecular-weight (MW > 3500 Da) are able to act as
antioxidants in all the used systems. The lower MW fraction (MW < 3500 Da) showed itself to be pro-oxidant in the microsome
system. The effects of thermal treatments such as boiling, freezing and freeze-drying were also investigated
Plant-based biocomposite films as potential antibacterial patches for skin wound healing
No full textNatural polymers represent a promising family of materials for the fabrication of skin wound dressings that can improve the healing process and the protection against pathogens. In this work, we present the preparation of natural polymeric films combining two plant-based polymers: zein, an alcohol-soluble protein from corn, and pectin, a hydrophilic polysaccharide of the plant cell wall. The effect of two different forms of pectin – low methoxy and amidated low methoxy – on the resulting biocomposite was investigated. Glycerol was added to improve the mechanical performances. The degradation assay in various buffers and thermogravimetric analysis highlighted the tendency of the composite films to degrade faster in water than the pure zein films, due to the pectin ability to be released from the protein matrix in an aqueous environment. Drug release was performed, confirming the results obtained with previous analyses. Antimicrobial assays indicated the ability of the developed biocomposite patches to inhibit the growth of three pathogens (Escherichia coli, Staphylococcus aureus, Candida albicans). The biocompatibility was confirmed in vitro with primary human dermal fibroblasts via MTS assay and cell morphology inspection. The results indicate the great potential of the presented plant-based biomaterials as drug delivery systems for the treatment of skin wounds
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