Field and laboratory tests of etched track detectors for 222Rn: summer-vs-winter variations and tightness effects in Maine houses.

Effects of tightness of homes and of bedrock character on indoor 222Rn concentrations were sought in 70 homes in the state of Maine by means of four 6- to 8-month-long surveys over a 1.5-yr period. Laboratory experiments were also performed that document the reliability of the track etching system used for the measurements.

Personnel neutron dosimetry using particle tracks in solids: a comparison.

Comparison of two nuclear track methods of dosimetry for fast neutrons shows similar uncertainties for manual counting of etched tracks as for electrochemical read-out by a commercial service. The standard deviation is approximately 30% under rigorous specification of conditions, i.e.

Theory of passive measurement of radon daughters and working levels by the nuclear track technique.

A theoretical basis is described for long-term measurement of the activities of the alpha emitters in air by the track-etching technique. Inference of the other activities allows working levels to be derived. A set of absorber foils allows the differing response to alpha particles of different energies to be used to identify the relative abundance of the alpha emitters and the importance of diffusion to surfaces.

Passive measurement of working levels and effective diffusion constants of radon daughters by the nuclear track technique.

Measurements were made of working level ratios and the effective diffusion constants of radon daughters using a special housing designed to provide a uniform diffusional environment at the passive detectors. For 2 of 7 exposures, the measured scale of the diffusion was too large to satisfy the uniformity requirement. For the other 5, it was satisfied and reasonable working level ratios (WLR) were obtained.

Indoor radon measurements in the New York Capital District.

Radon-222 concentrations have been measured in 21 "energy-efficient" homes and 14 conventional homes in the New York Capital District. Usual concentrations are averaged over six-month or 12-month periods using solid-state track detectors. Full-year averages are available for 23 of the homes, and the winter-to-summer variations have been observed.

Multiple congenital septal atresias of the intestine: histomorphologic and pathogenetic implications.

Congenital atresias of the gastrointestinal tract are usually single and divided into three forms on a morphologic basis. The septal or diaphragmatic type (type I) is the least common. We report an infant with multiple type I atresias involving both the small and large intestine and describe the unique histologic features of the septa: fragmentation of muscularis mucosa, multiple septal cysts lined by columnar epithelium, circular and longitudinal muscular layers, and absence of inflammation.

Allozymic heterozygosity and morphological variation in house sparrows.

Several reports have shown that greater heterozygosity (both between individuals and between populations) is associated with lower morphological variance and asymmetry. Most previous work concerned poikilothermic organisms (for example, fish, butterflies, lizards, shellfish, salamanders and plants). Reports concerning two homoiotherms gave conflicting results.

Indoor radon levels in the northeastern U.S.: effects of energy-efficiency in homes.

The expectation of elevated 222Rn levels in modern homes that have low air interchange rates with the out-of-doors caused us to survey both solar and conventional homes in northeastern New York State. The solar homes as a group have three times the 222Rn levels of the conventional homes, and specific problems exist that are introduced or exaggerated by modern construction. For example the highest two levels of radon in the solar homes give radiation doses over 30 yr that are known to produce lung cancer in 1% of uranium miners.

Evidence for active Na+ transport by cultured monolayers of pulmonary alveolar epithelial cells.

Primary cultured type II alveolar epithelial cells grown to confluence on nonporous surfaces form many small fluid-filled hemicysts or domes. These domes are generally thought to result from active transport of solutes from the medium above the cell monolayer to the substratum, with water following passively. We have investigated the characteristics of active transport by primary cultured monolayers of type II alveolar epithelial cells from rat lungs.

Effects of inhibition of RBC HCO3-/Cl- exchange on CO2 excretion and downstream pH disequilibrium in isolated rat lungs.

To determine the effects of the speed of the erythrocyte membrane chloride shift on pulmonary gas transfer, CO2 exchange and the kinetics of pH equilibration were measured with isolated rat lungs perfused with 20% suspensions of human erythrocytes. The lungs were ventilated with room air, and the inflowing perfusate blood gases were similar to those in mixed venous blood in vivo. All experiments were performed at 37 degrees C.

Isotopic disequilibrium of uranium: alpha-recoil damage and preferential solution effects.

Preferential loss of uranium-234 relative to uranium-238 from rocks into solutions has long been attributed to recoiling alpha-emitting nuclei. Direct evidence has been obtained for two mechanisms, first, recoil ejection from grains, and now release by natural etching of alpha-recoil tracks. The observations have implications for radon emanation and for the storage of alpha-emitting radioactive waste.

Apollo 14 and apollo 16 heavy-particle dosimetry experiments.

Doses of heavy particles at positions inside the command modules of Apollo missions 8, 12, 14, and 16 correlate well with the calculated effects of solar modulation of the primary cosmic radiation. Differences in doses at different stowage positions indicate that the redistribution of mass within the spacecraft could enhance safety from the biological damage that would otherwise be expected on manned, deep-space missions.

Cosmic-ray tracks in plastics: the apollo helmet dosimetry experiment.

Counts of tracks from heavy cosmic-ray nuclei in helmets from Apollo missions 8 and 12 show variations caused by solar modulation of the galactic cosmic-ray flux. Specific estimates of the biological damage to certain nonreplaceable cells by track-forming particles during these space missions indicate that the fraction of deactivated cells could range from a lower limit of 3 x 10(-7) to an upper limit of 1.4 x 10(-4).