Novel electrochemical method to evaluate the antioxidant capacity of infusions and beverages, based on in situ formation of free superoxide radicals.

This work reports a new method to evaluate the antioxidant capacity of infusions and beverages, based on superoxide radicals. Radicals produced by the enzymatic reaction between acetylcholinesterase and hypoxanthine oxidized antioxidant molecules present in commercially available samples or standard solutions, which was monitored by means of cyclic voltammetry using a carbon paste electrode. The Trolox equivalent antioxidant capacity (TEAC) of red wine, coffee and green tea determined using this method were: (1.20 ± 0.06), (0.90 ± 0.02), and (0.65 ± 0.02), respectively. This method suggested TEACred wine > TEACcoffee > TEACgreen tea, which is the same as DPPH, spectrophotometric method. However, the electrochemical one proposed here is rapid and simple.

Identification of COVID-19 Spreaders Using Multiplex Networks Approach.

In this work, we present a methodology to identify COVID-19 spreaders using the analysis of the relationship between socio-cultural and economic characteristics with the number of infections and deaths caused by the COVID-19 virus in different countries. For this, we analyze the information of each country using the complex networks approach, specifically by analyzing the spreaders countries based on the separator set in 5-layer multiplex networks. The results show that, we obtain a classification of the countries based on their numerical values in socioeconomics, population, Gross Domestic Product (GDP), health and air connections; where, in the spreader set there are those countries that have high, medium or low values in the different characteristics; however, the aspect that all the countries belonging to the separator set share is a high value in air connections.

Effective mercury(II) bioremoval from aqueous solution, and its electrochemical determination.

This work proposed mercury elimination using agricultural waste (Allium Cepa L.). The biomass removed 99.4% of mercury, following a pseudo-second order kinetics (r2 = 0.9999). The Langmuir model was adequately fitted to the adsorption isotherm, thereby obtaining the maximum mercury adsorption capacity of 111.1 ± 0.3 mg g-1. The biomass showed high density of strong mercury chelating groups, thus making it economically attractive. Also, the implementation of a mercury-selective electrode for continuous determination in real time is proposed; this electrode replaces techniques like atomic absorption spectroscopy, thus it can be applied to real time studies. This work therefore presents a new perspective for removing mercury(II) from contaminated water for environmental remediation.