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The wetting properties of aqueous solutions of two therapeutic pulmonary surfactants (T PS) with respect to solid surfaces with different degree of hydrophobicity θw have been studied. A special procedure for hydrophobization of the SiO2-glass hydrophilic surface allows the preparation of hydrophobic solid surfaces with different θw. The contact angles of drops from a TPS solution onto SiO2-glass surfaces have been measured as a function of their θw. The completely hydrophilic SiO2-glass surface is essentially hydrophobized by the animal-derived TPS Curosurf as well as by the synthetic TPS CHF 5633. The hydrophobization depends on the surfactant concentration - the contact angles increase with increasing the Curosurf concentration C in the low concentration range, but they remain almost constant in a wide range of C > 90 μg/ml. Similar are the θ (θw) curves for aqueous solutions of both TPS. The thickness h of the wetting thin liquid fi lms from aqueous solutions of Curosurf as well as of CHF 5633 on SiO2-glass surfaces depends on θw of the solid surface. The h(θw) curves always pass a minimum. The h-values, as well as the h(θw) curve, are mainly determined by the balance of the positive (repulsive) steric and negative (attractive) hydrophobic disjoining pressures, which depend on the orientations and conformations of the molecules adsorbed on the wetting fi lm surfaces from the very complicated multi-component aqueous solutions. Practically no signifi cant difference in the wetting behaviour of the aqueous solutions of the natural TPS Curosurf and the synthetic TPS CHF 5633 has been established, however about 25% less Curosurf than CHF 5633 was needed to achieve almost the same wetting behaviour. [ABSTRACT FROM AUTHOR]

The history of the scientific research in chemistry carried out through a century at the University of Sofia is briefly presented. Three arbitrary periods are distinguished: 1889 – beginning of 1920's, research in classical chemistry of 19th century; 1920's – end of 1950's, radical renovation which led to modern scientific research on European level in 1940's; beginning 1960's – end of 1980's, significant extensive development including new research directions and themes. The directors of research, professors and heads of departments are presented. [ABSTRACT FROM AUTHOR]

In this paper a short review of the history of Alexander von Humboldt Foundation, Bonn - Bad Godesberg, Germany, on the occasion of its 60th anniversary is presented. This outstanding German foundation is actually the third one with the same name. Earlier two other Alexander von Humboldt Foundations consequently existed and they consist its pre-history, which is also shortly reviewed. The establishment of the present Foundation in 1953, its development and growth, its activities, information about the six presidents and five executive directors, as well as the main features, principles and guidelines are considered. During the last 60 years the Alexander von Humboldt Foundation became an important institution for the promotion of international research cooperation, which significantly influences the world science. It supported more than 27700 Humboldt fellows to carry out scientific research in Germany, and they form a large "Humboldt family" - a world-wide network. Large number Bulgarian Humboldt fellows are among the best scientists in Bulgaria. [ABSTRACT FROM AUTHOR]