Publications by Year: 1992

Magdassi S, Royz M, Shoshan S. Interactions between collagen and perfluorocarbon emulsions. Int. J. Pharm.International Journal of Pharmaceutics. 1992;88 (1-3) :171 - 6.Abstract
The interactions between perfluorocarbon emulsion and both dissolved collagen and suspensions of collagen fibrils were studied in a new formulation suggested for enhancement of wound healing. Since the emulsion droplets are covered with a charged phospholipid monolayer, both elec. and hydrophobic interactions may exist. Electrophoretic mobility measurements which are conducted at various pH values, and light microscopy, revealed that the emulsion droplets were adsorbed onto the collagen fibrils, thus forming a new population of particles. This phenomenon was also obsd. at the pH values of the isoelec. points of collagen or lecithin, indicating possible hydrophobic interactions between collagen and lecithin. From adsorption expts., the area of collagen mol. at the interface was calcd. This suggested formation of an end-on oriented collagen mols. layered at the water-perfluorocarbon/lecithin interface. [on SciFinder(R)]
Levy N, Magdassi S, Bar-Or Y. Physico-chemical aspects in flocculation of bentonite suspensions by a cyanobacterial bioflocculant. Water Res.Water Research. 1992;26 (2) :249 - 54.Abstract
The biopolymer produced by Anabaenopsis circularis strain PCC 6720 was an effective anionic flocculant for bentonite suspensions. The presence of CaCl2 increased the flocculation efficiency significantly. From adsorption isotherms and zeta-potential measurements, it was concluded that the flocculation process is based on the bridging mechanism. The role of CaCl2 is to increase the initial adsorption of the biopolymer on the bentonite particles. It also decreases the neg. elec. charge of the bentonite particles and of the biopolymer mols. The dominant role of the bioflocculant in the flocculation process is discussed according to the theor. interaction energy curves. [on SciFinder(R)]
Giordano JP, Magdassi S, Frank SG, Fruman DH, Zakin JL. Prediction of emulsifiability of viscous crude oils with alkali treatment from interfacial tension measurements. Speculations Sci. Technol.Speculations in Science and Technology. 1992;15 (1) :24 - 9.Abstract
Low-viscosity concd. oil-in-water emulsions were studied in relation to transportation of viscous petroleums to refineries. Of 6 heavy crudes tested, 60% oil-in-water emulsions could be prepd. from 3 of them by treatment with NaOH over a fairly wide alkali/total acid no. range. Relatively unstable emulsions over a narrow range of NaOH addn. could be formed from one crude, and emulsions could not be formed with the other 2 at any alkali level. Interfacial tension measurements of 90% crude in PhMe solns. against 0.01% NaOH solns. gave results below 3.0 × 10-3 N-m-1 for the 3 crudes that could be emulsified, and over 6.8 × 10-3 N-m-1 for the other 3, indicating that such measurements can be used to predict the feasibility of prepg. emulsions by alkali treatment. Measurements at 77% crude in PhMe confirm these findings but the abs. values are generally somewhat higher. [on SciFinder(R)]