[en] Homograft replacement of the aortic and pulmonary valves is a well-established procedure. A simple and reliable method is required in the preparation, sterilization and storage of these valves. A study has been done on the effects of gamma radiation on homograft valves at varying radiation levels and temperatures. Valve cusps and aortic wall have been irradiated and then examined using normal histological techniques and electron microscopy. Bacteriological studies have been done for 2.5 Mrad dose. No positive cultures have been obtained from 64 strips from the aorta taken at the time of dissection of the same number of homograft valves. A satisfactory level of radiation has been found where valves are bacteriologically sterile with little or no alteration in structure or change in the physical characteristics of the homograft valve. Ten valves have been inserted into patients, replacing diseased aortic valves, and are working satisfactorily. The first two patients have been followed up in the clinic for six months following operation and are known to be in good health. These valves are working satisfactorily. (author)

[en] Last summer Robert J. Van de Graaff received the 1966 Tom W. Bonner Prize “for his contribution to and continued development of the electrostatic accelerator, a device that has immeasurably advanced nuclear physics.” The occasion was the banquet ceremony of the American Physical Society meeting in Mexico City, held jointly with the Mexican and Canadian Physical Societies.

[en] On the average overland atmospheric diffusion rates are shown to be three times more rapid than those with overwater trajectories when the water is colder than the air temperatures over the land. The transport distance required to complete the transition from overwater to overland diffusion is shown to be a function of plume height, wind speed, and vertical temperature profile. Diffusion models are suggested to account for the diffusion rates within this transition zone. Coastline atmospheric trajectories are discussed in terms of local effects which result in the daily reversals between land and sea breezes and of large-scale pressure gradient effects which generally result in straight-line trajectories. (author)

[en] More than 18 years of meteorological data have been collected by the Meteorological Group at the Argonne National Laboratory. These data have been useful in the day-to-day operations of the Laboratory and in the preparation of reactor hazard reports as well as in support of atmospheric research projects, such as our radon, wind profile, plume rise and smoke diffusion studies. A climatological report, covering 15 years of data, has been prepared and will be published soon. A summary of a study of the meteorological conditions giving rise to dew point inversions (moisture content increasing with height near the ground) is given as an example of the type of studies that can be made with these data. (author)

[en] For the precipitation scavenging of submicron particles, inertial effects are shown to be negligible by transforming Newton's law to the mass independent Smoluchowski equation. The importance of electrical effects can be displayed theoretically but its evaluation requires more specific information about the charges on raindrops and particles. Heat transfer data is utilized to calculate the washout coefficient and the result is found to be a factor of two to ten below Ziman's. (author)

[en] Since the formation of the Meteorology Group at Brookhaven National Laboratory, experimental diffusion studies have had a prominent part in its program. In recent years primary attention has been given to the dispersion and deposition of particles in the 3 to 10 micron range. These studies have been supplemented during the past ten years by a cooperative project between the Meteorology Group and the Botany Department of the New York State Museum and Science Service. This project is financed mainly by the U.S. Public Health Service and includes studies of dispersion and deposition of pollens from experimental sources of living plants. Since both of these programs involve dispersion over open terrain, an additional project was initiated several years ago to study dispersion of particulate clouds approaching and penetrating a forest. This study has the following objectives: 1. to determine the behaviour of the plume as it approaches the forest edge as a function of release site and meteorological conditions, 2. to determine the dispersion rate within the forest as compared to the rate over open terrain under similar conditions, and 3. to identify the mechanisms important in the removal of particles from the air within the forest. In support of these objectives a comprehensive study is being made of the wind and temperature structure within, above and around the forest. The dispersion experiments are similar in design and scale to others previously conducted over open terrain so results can be compared to other experiments as well as to theory. (author)

[en] The main studies carried out now in Portugal are aimed at the development of two types of uranium processing: - Conventional leaching by agitation ore finely milled in a sulfuric acid solution; - Leaching type ''heap leaching'' in which the ore is crushed and then sprayed with a piled sulfuric solution

[en] According to the Spanish program of nuclear reactors, the uranium requirements are estimated between 1400 and 1600 t until 1970 and between 11 000 and 14 000 t until 1980

[en] By way of introduction to a review of Research Projects of the Division of Radiological Health concerned with effects of radiation on the haematopoietic tissue in man and the experimental animal, I should like first to discuss briefly the organization of research. Our research is organized into three major disciplines: (1) Epidemiology, (2) Radiation biology, and (3) Environmental sciences. Briefly, epidemiology is concerned with studies, of populations and effects of radiation in.man; radiation biology is concerned with effects in the experimental animal under controlled situations and also concerned with basic research in cellular and sub-cellular effects; and environmental science is concerned with transport mechanisms in the biosphere and how these mechanisms may operate and be interrupted to reduce radiation hazard to man

[en] Whole-body radiation has long been known to have an ameliorative effect upon certain blood diseases, particularly the chronic leukaemias and polycythemia vera. More recently, large doses of whole-body radiation have been given to suppress the immune response and facilitate transplantation of tissues and organs. Meanwhile, there has been increasing interest in the effects of whole-body radiation in normal man because of possible opportunities for accidental exposure in industrial nuclear installations, military applications, and the exploration of space. The present report is based mainly on patients treated at the Medical Division of the Oak Ridge Institute of Nuclear Studies; a relatively small group of patients from the University of Cincinnati is included to expand the number of those with non-haematologic disorders