Antibacterial efficiency over time and barrier properties of wood coatings with colloidal silver

This work aims to represent a standard application for understanding the extent of the antibacterial efficacy of coatings with different amounts of colloidal silver on wooden surfaces over time. The key variable that was intended to be evaluated in this study was the "time efficiency," with concerns about the possible efficacy in the durability of the surfaces. By highlighting the "expiry date" of the agents, as in the case with other products, the study aimed to confirm the validity of the simulation tests conducted in the laboratory with degradation tests. Furthermore, the role of the silver amount on the barrier performance of the coatings was assessed by liquid resistance, water uptake, and perspiration tests, evaluating the aesthetic durability of the coatings by means of colorimetric analyses. Ultimately, this work demonstrates that these coatings may represent alternatives in terms of prolonged antimicrobial activity when compared with the biocide agents currently in use, capable to offer good resistance to detergent solutions and to water. Nevertheless, due to silver's susceptibility to extended exposure to acidic solutions, the findings of the research discourage the utilization of colloidal silver in wood paints intended for use in public settings

Colloidal silver as innovative multifunctional pigment: The effect of Ag concentration on the durability and biocidal activity of wood paints

This study aims to assess the effect of two different colloidal silver amount on the durability and biocidal activity of a water-borne wood paint. The influence of this multifunctional pigment on the aesthetical features of the coatings was evaluated by colorimetric measurements and optical microscopy observations. The durability of the samples was investigated by means of different accelerated degradation tests, such as the exposure in a climatic chamber and to UV-B radiations. Scanning electron microscope observations, infrared spectroscopy analysis and colorimetric inspections were carried out to highlight the residual influence of silver in altering the protective behavior of the paint. Moreover, the Ag-containing samples exhibited excellent antibacterial activity against Staphylococcus aureus and Escherichia coli, while colloidal silver did not introduce effective fungicidal performances against Coniophora puteana and Trametes versicolor fungi. Ultimately, this work demonstrates how colloidal silver can be used as a functional pigment in wood paint, capable of modifying the appearance of the coating, improving its antibacterial performance, without negatively affecting its protective performance

Growth of Listeria Monocytogenes in ready to eat salads at different storage temperatures and valuation of virulence genes expression

BACKGROUND: Vegetables are major components of a healthy and balanced diet. However, 25% of foodborne diseases are linked to the consumption of vegetables. STUDY DESIGN: The aim of this work was to assess the microbiological risks associated with consumption of ready to eat salads (RTE). METHODS: Microbiological challenge tests were carried out for the evaluation of the L. monocytogenes growth potential in RTE salads stored at different temperatures. RESULTS: The results indicate that L.monocytogenes was able to grow (δ ≥ 0.5) in all storage conditions considered at the end of shelf life. In order to evaluate the virulence role of L. monocytogenes, the temperature-dependent transcription of major virulence genes was also investigated by RT-PCR. CONCLUSIONS: The microbiological challenge test allowed us to confirm, as also demonstrated by other authors, that RTE salads are able to support the growth of L. monocytogenes strains (d δ≥ 0.5) stored under different temperatures

Facile route to effective antimicrobial aluminum oxide layer realized by co-deposition with silver nitrate

The emergence and spreading of the SARS-CoV-2 pandemic has forced the focus of attention on a significant issue: the realization of antimicrobial surfaces for public spaces, which do not require extensive use of disinfectants. Silver represents one of the most used elements in this context, thanks to its excellent biocidal performance. This work describes a simple method for the realization of anodized aluminum layers, whose antimicrobial features are ensured by the co-deposition with silver nitrate. The durability and the chemical resistance of the samples were evaluated by means of several accelerated degradation tests, such as the exposure in a salt spray chamber, the contact with synthetic sweat and the scrub test, highlighting the residual influence of silver in altering the protective behavior of the alumina layers. Furthermore, the ISO 22196:2011 standard was used as the reference protocol to set up an assay to measure the effective antibacterial activity of the alumina-Ag layers against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria, even at low concentrations of silver. Finally, the Ag-containing aluminum oxide layers exhibited excellent antimicrobial performances also following the chemical–physical degradation processes, ensuring good durability over time of the antimicrobial surfaces. Overall, this work introduces a simple route for the realization of anodized aluminum surfaces with excellent antibacterial properties

Molecular Effects of Doxycycline Treatment on Pterygium as Revealed by Massive Transcriptome Sequencing

Pterygium is a lesion of the eye surface which involves cell proliferation, migration, angiogenesis, fibrosis, and extracellular matrix remodelling. Surgery is the only approved method to treat this disorder, but high recurrence rates are common. Recently, it has been shown in a mouse model that treatment with doxycycline resulted in reduction of the pterygium lesions. Here we study the mechanism(s) of action by which doxycycline achieves these results, using massive sequencing techniques. Surgically removed pterygia from 10 consecutive patients were set in short term culture and exposed to 0 (control), 50, 200, and 500 µg/ml doxycycline for 24 h, their mRNA was purified, reverse transcribed and sequenced through Illumina’s massive sequencing protocols. Acquired data were subjected to quantile normalization and analyzed using cytoscape plugin software to explore the pathways involved. False discovery rate (FDR) methods were used to identify 332 genes which modified their expression in a dose-dependent manner upon exposure to doxycycline. The more represented cellular pathways included all mitochondrial genes, the endoplasmic reticulum stress response, integrins and extracellular matrix components, and growth factors. A high correlation was obtained when comparing ultrasequencing data with qRT-PCR and ELISA results

Aberrant DNA Methylation of Matrix Remodeling and Cell Adhesion Related Genes in Pterygium

10.1371/journal.pone.0014687PLoS ONE62

Chemical variability, Antifungal and Antioxidant Activity of Eucalyptus calmalldulensis Essential Oil from Sardinia

Essential oil (EO) from aerial parts of Eucalyptus camaldulensis Dehnh., growing wild in different localities of Sardinia (Italy), was extracted by steam distillation and analyzed by gas chromatography (GC) FID and GC-ion trap mass spectrometry (ITMS). The yields of EO (v/dry wt) ranged between 0.2-0.5%. Samples were harvested between April and December to study the seasonal chemical variability of the EO. The chemical composition varied depending on the different origins and showed strong fluctuation during the vegetative stage. Thirty-seven compounds, accounting for at least 97.7% of the total EOs were identified, the major components being p-cymene (27.8-42.7%), 1,8-cineole (4.1-39.5%), beta-phellandrene (3.9-23.8%), spathulenol (2.1-15.5%) and cryptone (3.2-10.2%). The oils possessed moderate amounts (1.4-4.7%) of two uncommon aldehydes, cuminal and phellandral. The essential oils were screened for their antifungal activities against common phytopathogenic fungi using the paper disk diffusion method and they showed activity at low doses against the fungi tested. The antioxidant activity, assessed by DPPH-test and expressed as Trolox equivalent antioxidant capacity, showed values ranging between 0.5 and 5.8 mmol/L