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After lighting homes, streets and buildings for over 100 years, the incandescent bulb created by T. A. Edison, will soon become a relic of the past. Many countries have taken steps to replace it to another more efficient light energy source. Additionally, the incandescent bulbs have been gradually replaced by fluorescent bulbs that are more economical and, currently, in residential lighting, their compact equivalents. However, this type of lamp is beginning to be replaced and the alternative that presents itself is the power LED. In Optics laboratories teaching is common to use several types of light sources, from a simple candle to semiconductor lasers. Thus, in experiments involving Geometric Optics and light polarization, among others, it is common to use traditional sources such as incandescence and low pressure gas. In experiments involving the phenomenon of light interference, it is easier to use sources of high grade of coherency, such as gas lasers and semiconductor lasers. The purpose of this paper is to present, in a simple and didactic way, a source of light that uses a LED power and show that it can replace, with many advantages, the light sources traditionally used in many optical experiments. [ABSTRACT FROM AUTHOR]

Following the appearance of several antimicrobial agents to control the spread of infections, two major challenges have emerged: (i) the occurrence and blowout of multiresistant bacteria and the increase of chronic diseases and (ii) difficult-to-eradicate infections. In this study, we tested five benzoylthiourea derivatives for their ability to inhibit and stop bacterial growth and evaluated the possible influence of 1,2,4-triazolyl-benzoylthiourea derivative 4 on the formation and eradication of Staphylococcus aureus biofilms. Benzoylthiourea derivatives 4, 6, 10, 11 and 13 were obtained in one or two steps with low cost and subjected to tests to identify their minimum inhibitory concentration (MIC) and minimum bactericidal concentration. In vitro tests were also performed to assess their effects on biofilm formation and in preformed biofilms and scanning electron microscopy was used to visualize the effects on biofilm formation. The 1,2,4-triazolyl-benzoylthiourea derivative 4 showed bacteriostatic activity against the S. aureus HU25 clinical strain with an MIC of 16 µg ml -1 , which is below the toxic concentration (at 2500 µg ml -1 , 62·25% of the cells remained viable). Compound 4 also effectively prevented biofilm formation at the three subinhibitory concentrations tested (1/2 MIC, 1/4 MIC and 1/8 MIC) as confirmed by scanning electron microscopy. For breakdown of formed biofilms, the main influence was at a subinhibitory concentration (1/2 MIC). These findings make compound 4 a strong candidate for studies on the development of new antimicrobial and antibiofilm agents., (© 2020 The Society for Applied Microbiology.)