Biomedical subjects

D Meyerhof

Publications and source records attributed to D Meyerhof.

4 recordsLinked to original sources

PubMed2004

Automated radioxenon monitoring for the comprehensive nuclear-test-ban treaty in two distinctive locations: Ottawa and Tahiti.

In preparation for verification of the Comprehensive Nuclear-Test-Ban-Treaty, automated radioxenon monitoring is performed in two distinctive environments: Ottawa and Tahiti. These sites are monitored with SPALAX (Systeme de Prelevement d'air Automatique en Ligne avec l'Analyse des radioXenons) technology, which automatically extracts radioxenon from the atmosphere and measures the activity concentrations of (131m,133m,133,135)Xe. The resulting isotopic concentrations can be useful to discern nuclear explosions from nuclear industry xenon emissions. Ambient radon background, which may adversely impact analyser sensitivity, is discussed. Upper concentration limits are reported for the apparently radioxenon free Tahiti environment. Ottawa has a complex radioxenon background due to proximity to nuclear reactors and medical isotope facilities. Meteorological models suggest that, depending on the wind direction, the radioxenon detected in Ottawa can be characteristic of the normal radioxenon background in the Eastern United States, Europe, and Japan or distinctive due to medical isotope production.

Air Movements↗

PubMed2003

Uranium gastrointestinal absorption: the f1 factor in humans.

The present investigation was undertaken by the Department of Health, Canada, to determine the most appropriate value to use for uranium gastrointestinal absorption (f1) in setting the guideline for drinking water. Fifty participants, free from medical problems, were recruited from two communities: a rural area where drinking water, supplied from drilled wells, contained elevated levels of uranium and an urban area where the water supplied by the municipal water system contained < 1 microg l(-1). Uranium intake through food, drinking water and other beverages was monitored using the duplicate diet approach. Intake and excretion were measured by inductively coupled plasma-mass spectrometry (ICP-MS) in samples collected concurrently from the same individuals over a 3 d period. The range of f1 values was between 0.001 and 0.06, with a median of 0.009. These values were independent of gender, age, duration of exposure, daily total uranium intake and allocation of intake between food and water. Consistent with the recommendation of ICRP Publication 69, 78% were below 0.02.

Absorption↗

PubMed1996

Dosimetry of an incident involving 14C.

High level contamination was observed on two workers during a routine hand check of personnel leaving a laboratory where barium carbonate labeled with 14C was handled. A third worker was found to have been exposed to airborne 14C (carbonate) aerosol during the investigation. Urinary excretion analysis and in vivo monitoring were carried out. This paper presents the results of more than one year of lung counting using phoswich detectors and gives some indication about the metabolism of the 14C over that period. Doses were difficult to estimate due to lack of information in the literature. Estimates were based on default parameters and information gathered in this study using ICRP 30 and the new ICRP lung models. These ranged from 0.3 mSv to 3 mSv depending on the assumptions and models.

Barium↗

PubMed1996

The BRMD thyroid-neck phantom: design and construction.

The Human Monitoring Laboratory, which acts as the Canadian National Calibration Reference Center for In Vivo monitoring, has constructed a robust neck-thyroid phantom for use in the Canadian Thyroid Intercomparison Program. The phantom is rugged and capable of being distributed through the mail with no expectation of a leak of radioactive materials; it is anthropomorphic; the thyroid inserts simulate 125I and 131I; the phantom can be used to mimic different layers of adipose tissue over the thyroid insert; and it is cost effective. This paper describes the design criteria and the manufacturing process; the performance characteristics have been described in an earlier publication.

Canada↗