demonstrated that the plants had a resistance which prever ted any damage.
In the few not infected, seeds were taken and planted in 1° fall. Resultant plants were inoculated with the rust disease but ontinued to
show resistance against it. As far as is. known, the new §g trains have the
desirable characteristics of the original Mohawk variety, including high
yield. Further experiments will be continued to determine applicability
to other varieties and crops.
Calorimetric evaluation for radiation units. Mod¢ rn radiation
dosimetry is largely based on the Bragg-Gray principle whi ch permits the
measurement of the amount of energy absorbed by tissue fr
Lonizing
radiations. Although the analysis and interpretation of adiation exknown in ergs per square centimeter and ergs per gram, re
actual calibration measurements are usually made with ion
rather than directly by a calorimetric method. This proc
customary since ionization measurements have been convent
ducible, whereas the direct calorimetric measurement has
cult. The necessary conversion of the ionization measure
lute units is simplified with the assumption of the Bragg
but is not always simple or certain. By the calorimetric
Sloan Kettering Institute has developed recently, it is n
determine quantitatively the relation between ionization
absorption) be
pectively, the
zation chambers
dure has been
mnt and repro-
ppeared diffient into absoGray relation
method which
w possible to
nd absorbed
energy as a function of atomic number of absorber and ene gy of X ray to
examine any limitations of the Bragg-Gray relation that m ght exist.
~
periments require that the radiation flux and its "dose"
Scientists working on this project suggest that t is calorimetric
method of flux determination be adopted as the fundamenta calibration of
the output of the roentgen-ray generators, particularly f r generators
above 1 Mev.
Radiogermanium inhalation studies. The usefulnes
topic materials in evaluation of industrial hazards is ex
recent report from the Medical Department of Brookhaven N
tory on a collaborative study with the U. 5S. Naval Hospit
New York.
of radioiso-
The study involved the use of pile-activated g
to trace the fate of this element after inhalation of gex
such as might be met during the production of various ele
which employ germanium crystals.
Rats were exposed for one hour to atmospheres con
activated germanium (as the metal itself or as the oxide,
lungs, liver, and kidneys were then removed and examined t varying intervals after exposure.
The gamma-radiation (11.4-day ha f-life) of the
Ge (1 permitted tracking.of the elimination of the elemen
from the lungs
and through the other organs.
The oxide is rapidly excre ed, and the
removal of the elemental germanium depends primarily on t e rate at which
it becomes oxidized upon standing in the lung.
No irrita ion, gross pathological changes, or other adverse effects were noted as
result of the
contact of germanium with the tissues. The findings show that this type
of exposure to germanium does not constitute a significan industrial
health hazard.
le
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