RADIOISOTOPES
Online ISSN : 1884-4111
Print ISSN : 0033-8303
ISSN-L : 0033-8303
Volume 13 , Issue 4
Showing 1-12 articles out of 12 articles from the selected issue
  • Hirotake KAKEHI, Noboru ARIMIZU, Kenji SAEGUSA, Hatsumi NAGASAWA, Kodo ...
    1964 Volume 13 Issue 4 Pages 275-281
    Published: July 15, 1964
    Released: September 07, 2010
    JOURNALS FREE ACCESS
    Measurements of low γ activities accumulated in a large volume sample, for example, excrement of a patient or a laboratory animal, are simplified by using a large volume well counter.
    A large plastic scintillator, provided with a large volume well sized 10 cm deep by 15 cm diameter, makes it suitable to assay large volume samples containing γ emitter, because of a comparatively low cost and high sensitivities. The detector has been installed in the Radioisotope Laboratory of the Chiba University Hospital since May, 1963.
    Background raises a problem with a plastic scintillator because integral counting is usually necessary. The detector assembly is housed in the lead shielding, at least 7.5 cm on any direction, insuring effective depression of background. A 5 in diameter photomultiplier tube is attached to the scintillator without a light pipe. High voltages of the photomultiplier tube ranging from 1, 050 to 1, 250 volt yield the maximum ratio of sample counting to background. The plastic scintillator shows no plateau region on a plateau curve and then the high voltage yielding the maximum ratio of sample counting to background is most suitable to assay the sample. The plastic scintillator is not capable of good pulse height resolution against γ rays as it does not exhibit a photoelectric peak. This fact makes it appropriate where only radioisotope is involved in a sample. The detector used can be cooled by dry ice packed in a small refrigerating chamber surrounding the photomultiplier tube. Cooling the tube results in a remarkable depression of noise levels, showing 30% reduction of background at -5°C compared with that of room temperature at 25°C. Counting geometry for samples, ranging in size from point sources to 1, 000 ml containers, is examined by using various radioisotopes containing identical activities in the well of the detector. Either movement of the sample on a vertical direction or increase of a sample volume is followed by a wide variety of counting efficiency ranging from 100 to 60%. However, movement on horizontal plane is not critical. By using a lead plate, 4 mm thick, covering the bottom of the well, the variety of efficiency can be minimized.
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  • Tadayoshi KUBOZOE, Joichi YOKOTA, Kumiko UMEZAWA
    1964 Volume 13 Issue 4 Pages 282-286
    Published: July 15, 1964
    Released: September 07, 2010
    JOURNALS FREE ACCESS
    A new sampler that has been successfully carried by a F-86-F jet fighter for collection of upper tropospheric carbon dioxide at an altitude up to 35, 000 feet is described. The sampler was designed to make use of the type 4 A molecular sieve (4 × 8 mesh) to absorb the carbon dioxide. The amount of carbon dioxide obtained in 1/2-1 hour of sampling time was 2-4 cc STP per gram of molecular sieve, the content of carbon dioxide absorbed at altitudes other than sampling ones was less than 5 %, being satisfactory for accurate 14C measurements.
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  • Hikaru SHIMOJIMA, Hiroyuki NAGAO, Toshimasa KAMADA
    1964 Volume 13 Issue 4 Pages 287-292
    Published: July 15, 1964
    Released: September 07, 2010
    JOURNALS FREE ACCESS
    The method of preparing tritium labelled compounds has been studied using high voltage discharge and microwave discharge. This method can be widely applied to various compounds including complicated ones which are not easily prepared with usual techniques.
    Labelled compounds with high specific activities have been found to be easily prepared in a short period in comparison to the contact method or recoil labelling method. The microwave discharging technique is found to be much superior to the high voltage discharging technique because of a simple discharge reactor tube and smaller production of impurities which have to be removed.
    Tritium labelled acetic acid was prepared with various conditions. For the purification of reactants, precise distillation and gas chromatographic techniques were applied after esterification of acetic acid. Labile tritium was completely removed while these purifications of the reactant were made.
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  • Hiroshi IMAMURA, Junro TSUJII, Makoto YOKOOJI
    1964 Volume 13 Issue 4 Pages 293-299
    Published: July 15, 1964
    Released: September 07, 2010
    JOURNALS FREE ACCESS
    Investigations were carried out on two wet-process rotary kilns of different sizes for the purpose of studying the material residence time, the rate of the charge in various sections of the kilns, and further the mixing character of raw meal in the kilns.
    These investigations were performed by adding a radioactive tracer to the raw meal at the kiln inlet. As a tracer, approximately 100 millicuries of 140La2O3, after being premixed with 10 kg of raw meal, was used in one test. Behaviours of the tagged raw meal in the kiln were observed through the kiln shell with thirteen scintillation detectors installed along the kiln axis. And two more scintillation detectors were set at the clinker belt conveyer and the circulating dust conveyer.
    Some other notices performing these tests are as follows :
    In the preliminary tests, it was confirmed by the double tracer method with cobalt oxide that 140La2O3 takes same behaviours in the kiln as raw meal. 140La2O3 was prepared by irradiation of high purity lantan oxide in the atomic reactor.
    Recording of measuring results was done with the aid of the automatic connection changing circuit, which operates between six scintillation detectors and two ratemeters. And all scintillation detectors were jacketed with water, to protect them against radiating heat from kiln or hot material.
    The following are observed from these tests :
    1. The rate of the charge increases gradually from the preheating zone towards the calcination zone, where it reaches over 3 m/min, and is remarkably reduced in the burning zone.
    2. The material residence time of main group of the tracer is unexpectedly short. But the circulating dust remains considerably long time in the kiln.
    3. The mixing of raw meal is promoted in the region of the chain zone, the lower part. of calcination zone and burning zone. Further, in the kiln 2, the flow of tracer is disturbed severely because of many inverse spiral grooves set of the surface of the fire-bricks stretched the kiln inside.
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  • Ginzaburo SUZUE, Keizo ORIHARA, Hiroshi MORISHIMA, Shozo TANAKA
    1964 Volume 13 Issue 4 Pages 300-303
    Published: July 15, 1964
    Released: September 07, 2010
    JOURNALS FREE ACCESS
    During the biosynthesis from 2-14C-mevalonic acid to phytoene, with the cell-free extract of phytoene accumulating mutant of Staphylococcus, a phosphorylated intermediate (isopentenylpyrophosphate) is separated and identified.
    The incubation mixture for this reaction contained 2-14C-mevalonic acid, Mg++, ATP, KF, 10-5M of iodoacetamide and partially purified enzyme. The ratio of 14C to 32P was 1 to 2 when AT32P was used as a cofactor. After the liberation of phosphate radicals with snake venom, liberated alcohol from the purified new substance was identified as isopentenol by the 3, 5-dinitrobenzoate derivative, and it was confirmed that the new substance was isopentenylpyrophosphate.
    14C-isopentenol was degraded with ozone, and after steam-distillation, formaldehyde-dimedone derivative was separated. It contained radioactivity and it was, therefore, concluded that methylene carbon of isopentenol is derived from carbon No. 2 position of mevalonate.
    The efficient conversion of Isopentenylpyrophosphate into phytoene is also confirmed.
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  • Yoichiro OMOMO, Masamichi SAIKI
    1964 Volume 13 Issue 4 Pages 304-307
    Published: July 15, 1964
    Released: September 07, 2010
    JOURNALS FREE ACCESS
    The investigation was carried out in order to find an improved method to determine iodine-131 in fresh milk.
    (1) In order to minimize iodine loss during ignition of milk, it was recommended to add an NaOH solution to the milk in ratio of milk to the 1 N NaOH solution as 1: 19.
    (2) A series of experiments indicates that inorganic iodine combines with fat and protein during experimental operation by Bergh's method. Since the iodine in fat-CCl4 layer is not determined, Bergh's method is thought to be unreliable.
    (3) To determine inorganic iodine, a composite system of ion-exchange and CCl4 extraction was recomended in the paper. If the assumption, about 90 percent of iodine in milk exists as inorganic form, is accepted, total iodine-131 concentration could be easily calculated from the measurement of the above.
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  • Jonosuke ATARASHI, Masaharu YOSHIMURA, Kazuo HARA, Akiro TERASHI, Tada ...
    1964 Volume 13 Issue 4 Pages 308-317
    Published: July 15, 1964
    Released: September 07, 2010
    JOURNALS FREE ACCESS
    A new method for measurement of mean cerebral circulation time has been successfully tested in this study as follows.
    When one of the scintillation detector head directs to the Willis' circle on the temporal area of human head and the other one directs to the cervical artery at the same side, two radioangiograms can be recorded.
    Therefore on the curve of radiocraniogram, if one indicates by Ac and Dc the appearance time of tracer and the disapperance time of maximal bolus, these may be represented as the upstanding point and the initial point of semilogarithmic phase.
    On the other hand, if Aa, Pa, Pv and Dv indicate the arterial appearance time, the arterial peak time, the venous peak time and the venous disappearance time on the cervical radioangiogram each other, and let Ma and Mv represent the mean point of arterial and venous tracer concentration, the following equation shall be obtained.
    Mean sinus-jugular balb circulation time=Dv-Dc
    Mean carotis-basilar artery circulation time=Ca-Pa
    and mean cerebral circulation time (MCCT)
    =Mv-Ma- { (Ca-Pa) + (Dv-Dc) }
    where, (Ca-Pa) is negligible
    Consequently MCCT≅Mv-Ma (Dv-Dc)
    The actual data of MCCT which were measured by this method, were 6.7 sec (average) on normal adults, 7.6 sec on hypertensives, 7.8 sec on post-cerebrovascular accidents and 8.3 sec on cerebral arteriosclerosis.
    The cerebral blood flow should significant reduction on the cases with cerebral vascular diseases which were observed the prolonged MCCT.
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  • [in Japanese], [in Japanese], [in Japanese]
    1964 Volume 13 Issue 4 Pages 318-319
    Published: July 15, 1964
    Released: July 21, 2010
    JOURNALS FREE ACCESS
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  • [in Japanese]
    1964 Volume 13 Issue 4 Pages 320-322
    Published: July 15, 1964
    Released: July 21, 2010
    JOURNALS FREE ACCESS
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  • [in Japanese]
    1964 Volume 13 Issue 4 Pages 323-328
    Published: July 15, 1964
    Released: July 21, 2010
    JOURNALS FREE ACCESS
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  • 1964 Volume 13 Issue 4 Pages 329-354
    Published: July 15, 1964
    Released: July 21, 2010
    JOURNALS FREE ACCESS
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  • 1964 Volume 13 Issue 4 Pages A365-A64
    Published: July 15, 1964
    Released: July 21, 2010
    JOURNALS FREE ACCESS
    Download PDF (6647K)
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