Sadao Kojima

High-throughput determination of theophylline and caffeine in human serum by conventional liquid chromatography-mass spectrometry

Automated high-performance liquid chromatography/mass spectrometry (HPLC-MS) with backflush column-switching was established for ultra-fast determination of theophylline and caffeine. A 400-μl portion of serum sample diluted with ultrapure water was injected and transferred to an Oasis HLB cartridge used as a precolumn for extraction. After switching the valves, the analytes trapped in the precolumn were eluted in the backflush mode and separated with a Chromolith Performance RP-18e column (C18-bonded monolithic silica); the compounds in column effluents were then detected by atmospheric pressure chemical ionization (APCI)-MS. The present method successfully provided high-throughput determination of theophylline and caffeine within 2 min. Satisfactory linearity, reproducibility, and sensitivity could be obtained for analysis of therapeutic and toxic levels of both compounds. Because of the very simple procedure and high throughput using the conventional HPLC system, the present method seems to have high potential in the fields of forensic toxicology and emergency medicine.

The JCO criticality accident at Tokai-mura, Japan: An overview of the sampling campaign and preliminary results

A criticality accident occurred on September 30, 1999 at the uranium conversion facility of the JCO Company Ltd. in Tokai-mura, Japan. A collaborating scientific investigation team was organized in two groups, the first to carry out research on the environmental impact (the environmental research group) and the second to assess the radiation effects on residents (the biological research group). This report concerns only the activities of the environmental research group. Four investigative teams were sent on different dates to the accident site and its vicinity to collect samples. About 400 samples were collected and subjected to analysis. An outline of the sampling campaign is presented here along with a brief chronology of the accident and the preliminary key results obtained by the independent research group are summarised in this Special Issue of the Journal of Environmental Radioactivity.

Yields and Recoil Properties of Products from the Interaction of Natural Copper with Intermediate-Energy 14N, 15N and 40Ar Ions

Reaction residues in the interaction of copper with intermediateenergy N, 1 N and 4 Ar ions (26 to 135 MeV/u) have been studied using non-destructive y-ray spectrometry. Formation cross-sections and average forward ranges were measured for 58 products. The data were used to obtain the mass yield distribution and the longitudinal momentum transfer. The results are compared with those from the studies reported on the interaction of copper with heavy projectiles, and discussed in terms of the transition of the reaction mechanism from low energy to relativistic energy.

Passive gamma-ray spectrometry for the determination of total fission events in the JCO criticality accident '99 in Tokai

Abstract The total number of fission events (TFE) in the JCO criticality accident was determined to be 3.43×10 18 with a 3 σ uncertainty of 0.73×10 18 by passive observation of the gamma-rays of 95 Zr , 103 Ru and 140 La – 140 Ba from outside the Uranium Conversion Building. The TFE value is in fairly good agreement with the analytical result from the uranium solution taken from the precipitation vessel, as reported in NSC-Nov, 1999. The agreement implies that the criticality accident took place in a small limited volume and that the majority of the fission products were retained in the precipitation vessel.

Monitoring of 131I in milk and rain water in Japan following the reactor accident at Chernobyl and estimates of human thyroidal dose equivalents.

Iodine-131 in milk and in rain water in Nagoya, Japan, (a location 8,000 km from Chernobyl) was monitored between May and July 1986. The 131I concentration in rain water ranged from 43.1 Bq L-1 on 4 May to 15 mBq L-1 on 12 July, and that in milk ranged from 21.8 Bq L-1 on 19 May to 11 mBq L-1 on 14 July. Iodine-131 concentrations in milk were estimated to be 4 to 6 times greater than those in rain water during the first few weeks after the accident. Both concentrations decreased with approximately the same effective half-life of 5.9 +/- 0.3 d for rain water and 5.0 +/- 0.2 d for milk. The 131I concentration in milk sold in markets varied from dairy to dairy and ranged from 0.07 to 0.2 times that in fresh milk. The maximum thyroidal dose equivalents estimated for an adult man and for a baby were far lower than the population annual dose equivalent to the thyroid from natural radiation.

Negative pion transfer process in a hydrogen-containing gas mixture

Annihilation γ-rays of π0 and pionic X-rays were measured in the gas mixtures of H2+Z and CH4+Z systems (Z=He, Ne, Ar and Kr). Pion capture probability of hydrogen atom was obtained from the annihilation γ-ray counts and the capture probability of Z atom was obtained from the pionic X-ray intensities. Transfer rates were determined from the data based on a combined large mesomolecular model. The transfer rates obtained were smaller than the systematics of the Russian group. Difference in the transfer rate between the gas and the liquid phases was found by a comparison of the present results with our previous ones.

Estimation of 134 Cs activity by a new approximation referred to the sum-peak method via a well-type Ge Detector

The activity of a sample containing 134Cs and 137Cs was estimated by means of a new approximation referred to the sum-peak method using a well-type Ge detector. The contribution of 137Cs to the total count rate was estimated from its peak count rate, and subtracted from the total count rate. Then the total count rate originating from 134Cs was estimated. Finally, the new method was applied and the 134Cs activity was estimated.

Determination of 134 Cs activity with the sum-peak method using a well-type germanium detector

The new sum peak method was applied to the samples containing both 137Cs and 134Cs using a well-type HPGe detector. The standard sources containing 137Cs and/or 134Cs were measured via a well-type HPGe detector. The activities estimated by the new sum-peak method agreed with the certified activities of the standard sources. It was proved that the activities of the samples collected around Fukushima Daiichi Nuclear Power Plant can be estimated by the new sum-peak method.

BEHAVIOR OF PIONIC HYDROGEN ATOMS IN GAS AND LIQUID PHASES

Pionic X-rays and π0 decays were measured for gas mixtures of H2/D2/CH4+SF6/Ar and the individual pure gases. Chemical effects on the pion transfer process from pionic hydrogen to other atoms were revealed by the pionic X-ray spectrum. The changes of the intensity patterns of pionic X-rays were compared with the predictions by a cascade calculation taking the transfer process into account. The mechanism of pion transfer process was discussed based on the results for gas phase and the previous ones for liquid phase.