Adsorption of Asphaltenes at Model Oil/Brine Interface: Influence of Solvent Polarity.

With the exploitation of heavy oil worldwide, the influence of asphaltene aggregation in the oil phase on the stability of crude oil emulsion has been paid more and more attention. Under this background, the effects of solvent polarity on model oil/brine water interfacial properties and emulsion stability are investigated in this study. It is demonstrated that there is a critical asphaltene concentration for the formation of a stable emulsion. This critical concentration is then found to increase from 80 to 500 ppm with the mixing ratio of methylnaphthalene to n-decane changed from 2:3 to 7:3. The dynamic light scattering experiment shows that the average aggregate size increases abruptly from 132.8 to 261.1 nm at 2:3 mixing ratio of methylnaphthalene to n-decane once the asphaltenes are added to above the critical concentration. Accordingly, the diffusion coefficient of the asphaltenes decreases sharply from 4.36 × 10-12 to 5.68 × 10-13 m2/s. Similar conclusions are also found for the other mixing ratios of 1:1, 3:2, and 7:3. Besides, the aggregation degree of asphaltenes weakens, and the diffusion coefficient enlarges at the same asphaltene concentration with the enhancement of the solvent polarity. Further, the interfacial experiments manifest that the equilibrium interfacial dilation modulus decreases from 38.42 to 23.65 mN/m with the mixing ratio of methylnaphthalene to n-decane increased from 2:3 to 7:3. It can thus be inferred that the structural strength of the interfacial film decreases with the enhancement of the solvent polarity.

Widely targeted quantitative lipidomics reveal lipid remodeling in adipose tissue after long term of the combined exposure to bisphenol A and fructose.

Adipose tissue is the main organ that stores lipids and it plays important roles in metabolic balance in the body. We recently reported in Human and Experimental Toxicology that the combined exposure to BPA and fructose may interfere with energy metabolism of adipose tissue. However, it is still unclear whether the combined exposure to BPA and fructose has the possibility to induce lipid remodeling in adipose tissue. In the present study, we performed a widely targeted quantitative lipidomic analysis of the adipose tissue of rats after 6 months of BPA and fructose combined exposure. We totally determined 734 lipid molecules in the adipose tissue of rats. Principal component analysis (PCA) showed the group of the combined exposure to higher-dose (25 µg/kg every other day) BPA and fructose can be distinguished from the groups of control, higher-dose BPA exposure and fructose exposure clearly. Partial least squares-discriminant analysis (PLS-DA) and univariate statistical analysis displayed lipids of PC(18:0_ 20:3), TG(8:0_14:0_16:0), TG(12:0_14:0_16:1), TG(10:0_16:0_16:1), TG(12:0_ 14:0_18:1), TG(14:0_ 16:0_16:1), TG(14:0_14:1_16:1), TG(8:0_ 16:1_16:2), TG(14:1_16:1_ 16:1), TG(16:1_18:1_18:1), TG(16:0_16:1_20:4) and TG(15:0_18:1_ 24:1) may contributed the most to the discrimination. These findings indicated that combined exposure to BPA and fructose has the potential to cause lipid remodeling in adipose tissue.

Impact of combined chronic exposure to low-dose bisphenol A and fructose on serum adipocytokines and the energy target metabolome in white adipose tissue.

Background: Adipose tissue is a dynamic endocrine organ that plays a key role in regulating metabolic homeostasis. Previous studies confirmed that bisphenol A (BPA) or fructose can interfere with the function of adipose tissue. Nonetheless, knowledge on how exposure to BPA and fructose impacts energy metabolism in adipose tissue remains limited.Purpose: To determine impact of combined chronic exposure to low-dose bisphenol A and fructose on serum adipocytokines and the energy target metabolome in white adipose tissue.Method: 57 energy metabolic intermediates in adipose tissue and 7 adipocytokines in serum from Sprague Dawley rats were examined after combined exposure to two levels of BPA (lower dose: 0.25, and higher dose: 25 µg/kg every other day) and 5% fructose for 6 months.Results: combined exposure to lower-dose BPA and fructose significantly increased omentin-1, pyruvic acid, adenosine triphosphate (ATP), adenosine monophosphate (AMP), inosine monophosphate (IMP), inosine, and l-lactate; however, these parameters were not significantly affected by higher-dose BPA combined with fructose. Interestingly, the level of succinate (an intermediate of the citric acid cycle) increased dose-dependently in adipose tissue, and the level of apelin 13 (a versatile adipocytokine) decreased dose-dependently in serum after combined exposure to BPA and fructose. Phosphoenolpyruvic acid, phenyl-lactate, and ornithine were significantly correlated with asprosin, omentin-1, apelin, apelin 13, and adiponectin, while l-tyrosine was significantly correlated with irisin and a-FABP under combined exposure to BPA and fructose.Conclusions: these findings indicated that lower-dose BPA combined with fructose could amplify the impact on glycolysis, energy storage, and purine nucleotide biosynthesis in adipose tissue, and adipocytokines, such as omentin-1 and apelin 13, may be related to metabolic interference induced by BPA and fructose exposure.