Effect of gentisic acid on the structural-functional properties of liposomes incorporating beta-sitosterol

Multifunctional liposomes incorporating beta-sitosterol were developed for delivery of gentisic acid (GA). The interactions of both compounds with phospholipid bilayer were interpreted viaeffects of different beta-sitosterol content (0, 20 and 50 mol %) and different gentisic acid to lipid ratio (n(GA)/n(lip) from 10(-5) to 1) on membrane fluidity and thermotropic properties. Multilamellar vesicles of phosphatidylcholines (with size range between 1350 and 1900 nm) effectively encapsulated GA (54%) when n(GA)/n(lip) was higher than 0.01. Suppression of lipid peroxidation was directly related to concentration of GA. The resistance to diffusion of gentisic acid from liposomes increased for (similar to)50% in samples incorporating 50 mol % beta-sitosterol compared to sterol-free liposomes. Finally, simulated in vitro gastrointestinal conditions showed that the release was mainly affected by low pH of simulated gastric fluid and the presence of cholates in simulated intestinal fluid, rather than by enzymes activity

Correlates of business survival: empirical evidence on youth-owned micro and small enterprises in Urban Ethiopia

Abstract This paper investigates the effects of person-, firm-, industry-, and business strategy-specific characteristics on the survival of youth-owned urban micro and small enterprises in Ethiopia. It employs nonparametric and semi-parametric methodologies using a retrospective data. The hazard rate reaches the highest point at business 2 years for micro enterprises and 4 years for small enterprises. Owner-, firm-, and industry-specific characteristics are important factors for micro and small enterprises’ (MSEs’) survival. Marketing and financial management strategies are playing a crucial role on extending MSEs’ survival duration. The study implies there should be more effective and longer period of support for micro than small enterprises

Size and Molecular Flexibility Affect the Binding of Ellagitannins to Bovine Serum Albumin

Binding to bovine serum albumin of monomeric (vescalagin and pedunculagin) and dimeric ellagitannins (roburin A, oenothein B, and gemin A) was investigated by isothermal titration calorimetry and fluorescence spectroscopy, which indicated two types of binding sites. Stronger and more specific sites exhibited affinity constants, K1, of 104–106 M–1 and stoichiometries, n1, of 2–13 and dominated at low tannin concentrations. Weaker and less-specific binding sites had K2 constants of 103–105 M–1 and stoichiometries, n2, of 16–30 and dominated at higher tannin concentrations. Binding to stronger sites appeared to be dependent on tannin flexibility and the presence of free galloyl groups. Positive entropies for all but gemin A indicated that hydrophobic interactions dominated during complexation. This was supported by an exponential relationship between the affinity, K1, and the modeled hydrophobic accessible surface area and by a linear relationship between K1 and the Stern–Volmer quenching constant, KSV