Weizmann Institute accelerators have been long used to explore the properties of atomic nuclei, but now they also contribute to the solution of a variety of medical, ecological, and other problems. Many of these projects are directed by investigators from other research institutions.
Prof. Michael Paul of the Hebrew University, for example, utilizes the Koffler Accelerator of the Canada Centre of Nuclear Physics as an extremely sensitive mass spectrometer in order to follow the movement of man-made isotope calcium - 41 in the body. His investigations promote an understanding of the bone-weakening disease, osteoporosis. Paul and colleagues are also tracing the environmental impact of nuclear energy exploitation by determining variations in radioisotope iodine-129 (a by-product of modern nuclear fission reactors) in ice cores from Greenland. Another group, including Dr. Yeshayahu Lifshitz of Israel's Nahal Soreq Nuclear Research Center and Prof. Michael Hass of the Institute's Nuclear Physics Department, uses the Pelletron to simulate the radiation of outer space. This enables study of the reliability of electronic chips used in satellites.
Prof. Jacob Klein and his group of the Institute's Department of Materials and Interfaces are working on the 3 MV Van de Graaff accelerator. Their investigation of nuclear reactions in polymers sheds light on how the chemical structure and size of individual polymer molecules provide information on the physics of polymeric materials, including their stability, thin-film structure, and transport properties.
The Institute's third accelerator, the EN Tandem, is used by a Tel Aviv University group to develop Israel's first free-electron laser (FEL), the most powerful type of laser known to science. FELs may eventually be a key component in the production of environmentally clean energy via magnetic confinement nuclear fusion.
Fundamental research continues at the Pelletron Accelerator. Profs. Cyril Broude and Michael Hass of the Nuclear Physics Department are probing the shapes, magnetism, and other properties of nuclei. These determinations help provide a better understanding of the forces operating between their component protons and neutrons. Another group, headed by Professors Zeev Vager (Nuclear Physics Department) and Ron Naaman (Chemical Physics Department), is applying its own novel method, involving both lasers and Coulomb explosion imaging, to determine the structure of molecular species, work important for verifying theoretical models of molecular structure.
Prof. Klein holds the Herman F. Mark Chair of Polymer Physics; Prof. Naaman, the Aryeh and Mintzi Katzman Chair; and Prof. Vager, the Isidor I. Rabi Chair of Physics.
Shedding Light on Infertility
The findings may help shed light on the cause of many unexplained cases of repeated miscarriages and infertility among women. It is also hoped that the research could eventually lead to techniques for improving the success rate of in-vitro or test-tube pregnancies.
These studies are an outgrowth of Dr. Tartakovsky's earlier work which led to the discovery of a particular cytokine, CSF-1, that impairs fertility in mice. Since some cytokines block the action of others, Tartakovsky sought to identify growth factors that might possibly promote pregnancy. He eventually found two: tumor necrosis factor-alpha (TNF-a) a pro-inflammatory substance produced by many tissues, and granulocyte macrophage colony stimulating factor (GM-CSF), a promoter of white blood cell production.
Tartakovsky's experiments showed that the abortion-inducing effects of CSF-1 could be largely overcome by parallel injections with pregnancy-promoter GM-CSF. He also demonstrated that TNF-a dramatically reduced miscarriages in a strain of mice highly prone to spontaneous abortions. Moreover, CSF-1-induced embryo damage was found to occur before embryo implantation, and correcting this effect must be attempted at an early phase if the embryo is to be salvaged.
This latter finding could have implications in human test-tube embryo implantation and may suggest a possible strategy for improving the low success rate (about 20%) associated with this procedure.
Dr. Tartakovsky holds the Pauline Recanati Career Development Chair in Immunology.