Obituary: Professor Alex Silberberg

Alexander Silberberg, physical chemist and biorheologist: born Vienna 24 February 1923; married; died Israel 12 September 1993.

ALEX SILBERBERG was a leading figure in the field of biorheology - the study of the flow of fluids in biology and medicine, taking in the working of cartilage, blood and blood vessels.

Silberberg was born in Vienna in 1923 and settled in South Africa in 1935. After graduating in 1944, with a BSc in Chemical Engineering from the University of Witwatersrand, Johannesburg, he served from 1944 to 1946 in the South African Corps of Signals.

He then entered the University of Basle, Switzerland, to study under the distinguished physical chemist Professor W. Kuhn and received the Ph D degree in 1952, summa cum laude, for his thesis 'Interfacial Tension and Phase Separation in Two Polymer-Solvent Systems'. He worked as special assistant to Kuhn in 1952-53. He was appointed to the Weizmann Institute of Science, Rehovot, Israel, in 1953 and spent the remainder of his career at the institute, being promoted Research Associate in 1954, Senior Scientist in 1959, Associate Professor in 1963 and Professor in 1970. He was the first incumbent of the Joseph and Marian Robbins Chair of Biorheology at the institute.

Silberberg was highly gifted, possessing strong scientific intuition and outstanding ability in physical chemistry and physiology. These endowments allowed him to make important contributions over a wide area of science, including macromolecular physics and chemistry, biorheology and molecular physiology. He achieved particular distinction in the difficult field of associating the microscopic properties of colloidal systems - where membranes either restrain or let through substances in solution - with their macroscopic behaviour.

Combined with singular warmth and a prodigious capacity for work, his attributes also made him in great demand internationally. To mention only a few, he held visiting professorships at the University of California, San Diego, the Oersted Institute, University of Copenhagen, Bristol University, Imperial College, London, and Columbia University, New York.

His clarity of thought and organising skills also made him indispensable on the councils of many societies. He was Past President and a Member of Council, European Microcirculation Society, Past President and a Member of Council, International Society of Biorheology, Ordinary Member, Divisional Committee, Macromolecular Division, IUPAC and Member of Council of the International Association of Colloid and interface Scientists. He was Editor-in-chief of Biorheology and Assistant Editor of the Journal of Rheology and his editorial advisory work extended to many other journals.

Above all, Alex Silberberg will be remembered for his enthusiasm for his subject, as a source of inspiration to co-workers and students alike, and as a founder and unswerving promoter of the International Society of Biorheology. He was the recipient of the Poiseuille Gold Medal, the society's highest award.

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