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Selenium is an essential inorganic compound in human and animal nutrition, involved in the proper functioning of the body. As a micronutrient, it actively contributes to the regulation of various metabolic activities, i.e., thyroid hormone, and protection against oxidative stress. However, Se exhibits a narrow concentration window between having a positive effect and exerting a toxic effect. In higher doses, it negatively affects living organisms and causes DNA damage through the formation of free radicals. Increased reactivity of Se anions can also disrupt the integrity and function of DNA-repairing proteins. As the permissible concentration of Se in drinking water is 10 µg/L, it is vital to develop sensitive and robust methods of Se detection in aqueous samples. In this study, for the first time, we proposed a selective aptamer for selenate ion detection, chosen following the SELEX process, and its application in the construction of an electrochemical aptasensor towards SeO42− ions. Measurement conditions such as the used redox marker and pH value of the measurement solution were chosen. The proposed aptasensor is characterized by good selectivity and an LOD of 1 nM. Conditions for biosensor regeneration and storage were also investigated in this research. [ABSTRACT FROM AUTHOR]

This article describes one of the many hybrid language varieties spoken in the United States that were formed through language contact in immigrant contexts: the Polish-and- American-English hybrid language referred to as polsko-amerykański in Polish-language sources, which I translate as Polamerican. The article traces Polamerican's history from the late 19th century to today, and examines some of its lexical, morphophonological, and phonetic features. I argue that Polamerican demonstrates over 100 years of continued development in the United States, with many of its features dating back to the first Polish settlements, and that its hybridized form reflects the particular, historically situated immigrant experience of its speakers. Crucially, Polamerican - like other hybrid languages - is a new, locally developed and contextualized form, rather than a mixture of or alternation between two separate varieties. [ABSTRACT FROM AUTHOR]