Dietary intake of toxic and essential trace elements by the children and parents living in Tokyo Metropolitan Area, Japan.

This study estimated the dietary intakes of 25 pairs of Japanese children and their parents to 12 toxic and essential trace elements using 7-day duplicate diet composites. The estimated intakes of lead (children = 5.34 microg day-1, adults = 6.74 microg day-1) and tin (162 and 152 microg day-1) were below tolerable limits, but large difference in aluminium intakes (7.32 and 12.1 mg day-1) among the subjects warranted further investigations. Intakes of cadmium in both children and adults (13.2 and 15.9 microg day-1) were high, but a low uranium (U) intake was observed (0.593 and 0.587 microg day-1). Intakes of copper (567 and 784 microg day-1), manganese (1.56 and 2.72 mg day-1), zinc (4.93 and 6.75 mg day-1), and molybdenum (103 and 131 microg day-1) were close to the recommended values. Concentrations of chromium, nickel and selenium were lower than the detection limits in most cases.

Formation of bioorganic compounds in simulated planetary atmospheres by high energy particles or photons.

Various types of organic compounds have been detected in Jupiter, Titan, and cometary coma. It is probable that organic compounds were formed in primitive Earth and Mars atmospheres. Cosmic rays and solar UV are believed to be two major energy sources for organic formation in space. We examined energetics of organic formation in simulated planetary atmospheres. Gas mixtures including a C-source (carbon monoxide or methane) and a N-source (nitrogen or ammonia) was irradiated with the followings: High energy protons or electrons from accelerators, gamma-rays from 60Co, UV light from a deuterium lamp, and soft X-rays or UV light from an electron synchrotron. Amino acids were detected in the products of particles, gamma-rays and soft X-rays irradiation from each gas mixture examined. UV light gave, however, no amino acid precursors in the gas mixture of carbon monoxide, nitrogen and nitrogen. It gave only a trace of them in the gas mixture of carbon monoxide, ammonia and water or that of methane, nitrogen and water. Yield of amino acid precursors by photons greatly depended on their wavelength. These results suggest that nitrogen-containing organic compounds like amino acid precursors were formed chiefly with high energy particles, not UV photons, in Titan or primitive Earth/Mars atmospheres where ammonia is not available as a predominant N-source.

A beamline for photochemical processes at atmospheric pressure.

A beamline especially designed for atmospheric photochemical reactions has been constructed at the NTT synchrotron radiation facility. By inserting a buffer helium chamber with Be and Si(3)N(4) partition windows between the beamline and the reaction chamber, studies can be performed without the differential pumping systems normally used in existing photochemistry beamlines. The reaction chamber is equipped with a gas supply system and analysis systems to investigate gas-phase and surface reactions. Purging using dry purified gases in combination with water-bubbling gives effective control of water concentration in the reaction chamber.

Synchrotron-radiation-induced formation of salt particles on an X-ray lithography mask.

The suppression and removal of contaminants on X-ray masks are required for the application of X-ray lithography to practical semiconductor production, because contamination is easily transferred to the replicated resist patterns and degrades the LSI patterns. In order to study contamination of a Ta/SiN X-ray mask, its growth process was investigated using an atmospheric reaction chamber and in situ observation apparatus for gases at atmospheric pressure. It was found that the contamination particles were ammonium sulfate and oxalate. The sources of the salt particle were also identified.