The object of this study was to determine the nature of the free radicals induced in ferrocene by Co60 gamma rays. The irradiations were carried out on the powder at 77°K and on the single crystals at 193°K. The variation of the splitting factor, g, of the signals observed when the single crystals were oriented at different angles relative to the external magnetic field direction, indicated the existence of three types of resonance peaks. It was possible to correlate these variations with the molecular orientations in the crystal unit cell and with the spatial arrangement of the molecular orbitals. Taking into account the spectral changes observed after thermal annealing of the crystal, the existence of the following free radicals has been suggested: 1) a straight molecule-ferricinium ion, 2) a bent molecule-ferricinium ion, and 3) a cyclopentadienyl radical with four protons, the fifth having been transferred to the iron atom. A signal with a cylindrically symmetric g tensor, observed at 77°K, has been assigned to another radical but its nature was not fully established.

Several important metabolic processes in plants involve the conversion of triose phosphate to hexose monophosphate. These include the synthesis of carbohydrates from precursors such as pyruvate and acetyl-coenzyme A, the reductive pentose phosphate cycle of photosynthesis, and the oxidative pentose phosphate cycle. This conversion cannot be accomplished solely by glycolytic enzymes because of the irreversible nature of phosphofructokinase. Racker and Schroeder (1958) have suggested two possible enzymic pathways for the formation of fructose 6-phosphate from triose phosphate. The most direct route is via a phosphate specific for the phosphates attached to carbon-1 of FDP. A combination of aldolase, transaldolase and sedoheptulose diphosphates may provide an alternative pathway.

The radiation of the Van Allen belts and the solar flares consists primarily of electrons and protons, the biological effects of which are reasonably well known. However, there is a very small component of the galactic cosmic rays which consists of stripped atomic nuclei of atoms as heavy as iron. The biological effects of such particles have not been extensively investigated because it is impossible to produce them in the laboratory with an energy high enough to use for mammalian experiments. Consequently it has been necessary to approach the problem by indirect methods.

Despite similar atomic arrangement, Brucite (Mg(OH)2) and phlogopite (KMg3(OH)2(Al,Si3)O10) present striking difference in their infrared spectra. A single absorption band is observed in phlogopite whence brucite possesses a total of 15 bands on both sides of the fundamental. A comparison of the hydroxides with micas provides supporting evidence that the complexity of the hydroxide spectra is due to interactions between neighboring hydroxyl groups. Each mineral contains a layer of magnesium ions possessing trigonal symmetry. Both minerals contain hydroxyl ion is located in such a way that it is in contract with three magnesium ions.

Much of the early work in radiation biology was predicted on the assumption that radiation effects could be understood in terms of a single mechanism. This "single mechanism" was studied on appropriate biological test objects that could be developed into biological dosimeters. Attempts were made to assess the properties of "the" biological effects from the relations of "biological dose" (skin dose, bean dose, fly dose, etc.) to physical parameters of irradiation. Notwithstanding the rigidity of this approach, some useful generalizations emerged. During the past 20 years or so, it has become increasingly obvious that ionizing radiations may affect living systems in different ways, and that what is true in one cell, tissue, or species and in one set of circumstances does not necessarily apply to another situation. Accordingly, the search for a single mechanism was replaced by dedicated application to specific detail. In consequence, we now know a great deal about the fine structure of some radiation effects, and there is once again a tendency to formulate generalizations. This paper will attempt to analyze the mechanism of a well-defined syndrome that arises in certain cell systems after a single dose of ionizing radiation. Our attention will be directed mainly to …

Information on the metabolism of fission products in man has been obtained largely from studies carried out with parenterally-administered soluble salts of radioisotopes administered in medical treatment or in tracer studies. The recent development of the whole-body gamma spectrometer with its highly sensitive detection system has been of considerable value in extending these studies by providing data on very low levels of isotopes in man over long periods of time.