Suppression of menstruation. A hygienic measure in the care of mentally retarded patients.
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Adolescent↗
Biomedical subjects
W M Morris
Publications and source records attributed to W M Morris.
The standardization of 33P by the TDCR efficiency calculation technique.
The activity of the pure beta-emitter phosphorus-33 (33P) has been directly determined by the triple-to-double coincidence ratio (TDCR) efficiency calculation technique, thus extending the number of radionuclides that have been standardized by this simple, non-extrapolation liquid scintillation (LS) method. The major advantage of inherently accounting for chemical quenching without the need for additional external measurements is demonstrated. The 33P solution activity concentration was verified by tracing with cobalt-60, utilizing 4pi(LS)beta-gamma coincidence counting. Agreement to within 1.2% confirmed the reliability of the TDCR measurements.
Algorithms↗
Direct activity determination of 54Mn and 65Zn by a non-extrapolation liquid scintillation method.
The measurement of 54Mn and 65Zn by liquid scintillation coincidence counting results in low detection efficiencies. The activity obtained from the extrapolation of efficiency data can therefore become problematic if curvature is present. The simple decay scheme exhibited by these radionuclides, with the emission of an energetic gamma ray, allows the absolute activity to be determined from 4pie-gamma data by direct calculation without the need for efficiency extrapolation. The method, which relies on determining the probability of the gamma-ray interacting with the scintillator solution, is described and validated by measurements made on 60Co.
Algorithms↗
Preparation of solid water-equivalent radioactive standards.
The use of a superabsorbent polymer to prepare water-equivalent volume standards by solidification without the need of irradiation to effect the polymerization process, is described. Less than 40 g of the polymer is needed to solidify 1 litre of solution. Monte Carlo simulations of the gamma-ray escape probability indicate that the mixture is water-equivalent to better than 1.0%. During preparation, the solidified material can be mixed until homogeneity is achieved. Comparative measurements made before and after solidification confirmed the homogeneity and demonstrated water equivalence.
Absorption↗