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Abstract Polymer - surfactant aqueous systems are important for a variety of industrial applications. The properties of those systems among other depend on the interactions between them. The aim of this work was to determine interactions between anionic polymer - xanthan gum and anionic surfactant - SDS or nonionic surfactant - Tween 80. In order to get better insight into the occurrence and possible mechanism of interactions several techniques were used such as FTIR, viscometry, conductometry, tensiometry, fluorimetry as well as SEM analysis. The results obtained by the combination of all those techniques showed that xanthan gum – SDS/Tween 80 interactions existed. Structural changes of xanthan gum molecules in presence of both surfactants were obtained by viscometry and SEM. The characteristic interaction points (CAC and PSP) were determined by measuring surface tension and specific conductance of pure surfactant aqueous solutions and their mixtures with xanthan gum. The values of PSP were proportional to the polymer concentration. After overcoming electrostatic repulsion between xanthan gum and SDS, they form complexes through hydrophobic mechanism and enhance adsorption of SDS molecules at the water – air interface. Unlike SDS, Tween 80 mainly interacts with xanthan gum in the bulk creating hydrogen bonds as well as by hydrophobic interactions. The results of fluorescence measurements expressed as I 1 /I 3 ratio additionally confirmed that the mechanism of interactions between xanthan gum and examined surfactants was mainly through hydrophobic interaction and by creation the hydrogen bonds with Tween 80 as through electrostatic repulsion with SDS. Graphical abstract Image 1 Highlights • Occurrence and mechanism of interactions in the xanthan gum –SDS/Tween 80 system. • Interactions between xanthan gum and SDS occurred through electrostatic repulsion and hydrophobic mechanism. • Xanthan gum-Tween 80 complexes are formed dominantly through hydrophobic interaction and hydrogen bonds. [ABSTRACT FROM AUTHOR]

The goal of this cross-sectional study was to examine the occurrence of bisphenol A (BPA) in the morning spot urine taken from 145 female volunteers of various ages. Total urine BPA concentration was detected in 38.6% samples in the 0.92–70.96 μg/g Cr range. The majority of BPA + women belonged to the 25 + body mass index (BMI) group (54.5% were overweight and 43.4% were obese women). Occurrence of BPA in the urine samples was higher at 40 + ages. The maximum BPA concentration of 70.96 μg/g Cr was detected in the urine sample of an obese woman. It is known that BPA is highly toxic in vitro . In this study BPA impaired significantly the growth of all investigated cell lines, i.e. the EC 50 values were reached at very low concentrations, in the range from 3.24 to 34.85 μg/mL. The obtained in vivo results suggest that a higher exposure to BPA could contribute to weight problems in women and the absence of the BPA in vitro selective toxicity studies indicates to its general toxic mode of action and raises awareness of the health risks associated with its ubiquitous presence in the environment. [ABSTRACT FROM AUTHOR]