Tetramethylsuccinonitrile in polyvinyl chloride products for food and its release into food-simulating solvents

The content of tetramethylsuccinonitrile (TMSN), the main decomposition product of 2,2'-azobis-isobutyronitrile, in polyvinyl chloride (PVC) products used for food packaging, were examined as well as food-simulating solvents. The TMSN concentration in 17 PVC products ranged from below the detection limit, 0.05 mg/kg, up to 523 mg/kg. The release of TMSN from two PVC products into five kinds of food-simulating solvents at 60 degrees C for 30 min was observed, except for 1 +/- 1 micrograms/kg of TMSN in n-heptane from a PVC bottle containing 523 +/- 30.4 mg/kg of TMSN. The detection limit of TMSN in the food-simulating solvents was 1 micrograms/kg. When pieces of the bottle were stored in olive oil at 40 degrees C for 120 days, 5 +/- 1 micrograms/kg of TMSN was detected in the oil. The release of TMSN from the pieces of the bottle into olive oil between 80 and 140 degrees C depended on the formula ln y = 0.08786x-5.696, r = 0.9927, where y is the concentration (microgram/kg) of TMSN in olive oil, x is the temperature (degrees C), and r is the correlation coefficient.     

Linearized method: A new approach for kinetic analysis of central dopamine D(2) receptor specific binding

We proposed a new method (;linearized method') to analyze neuroleptic ligand-receptor specific binding in a human brain using positron emission tomography (PET). We derived the linear equation to solve four rate constants, k(3), k(4), k(5), k(6) from PET data. This method does not demand a radioactivity curve in plasma as an input function to the brain, and can perform fast calculations in order to determine rate constants. We also tested the nonlinearized method including nonlinear equations which is a conventional analysis using plasma radioactivity corrected for ligand metabolites as an input function. We applied these methods to evaluate dopamine D(2) receptor specific binding of [(11)C] YM-09151-2. The value of B(max)/K(d)=k(3)/k (4) obtained by the linearized method was 5.72+/-3.1 which was consistent with the value of 5.78+/-3.4 obtained by the nonlinearized method.     

Isotope 18O/16O ratio measurements of water vapor by use of the 950-nm wavelength region with cavity ring-down and photoacoustic spectroscopic techniques

Two optical methods, cavity ring-down spectroscopy and photoacoustic spectroscopy, are applied to the measurement of the isotope ratio 18O/16O in water-vapor samples with a Nd3+:YAG pumped-dye laser. The combination band of (2v1 + v3) in the 960-nm region of water molecules is investigated for two standard water samples, the Vienna Standard Mean Ocean Water and the Standard Light Antarctic Precipitation. The results demonstrate that the two methods have the potential of compact systems for in-situ measurements of H2O isotope ratio in the environment.     

Three-Dimensional Numerical Simulation of Helically Propagating Combustion Waves

In the present paper, by using a mathematical model for self-propagating high-temperature synthesis, we reveal the three-dimensional structure of so-called spin combustion wave on the inside of cylindrical sample. It is shown that an isothermal surface of regular spin combustion wave has some wings of which number is the same as that of reaction spots on the cylindrical surface and that the isothermal surface with helical wings rotates down with time. Because of this propagating pattern, in this paper, we adopt the more suitable term helical wave. We also obtain the following existence conditions of a helical wave: If physical parameters are set so that a pulsating wave exists stably for the one-dimensional problem, then a helical wave takes the place of a pulsating wave when the radius of cylindrical sample becomes large.     

TEM,XPS and SIMS Analyzes on Grain Boundary of Lanthanum Chromites

The morphological characteristics, chromium valence state, and cation transport in the vicinity of grain boundary in La_1-xCa_xCrO₃ were investigated by using TEM/EDS, XPS and SIMS techniques. The width of grain boundary was around 1 nm where anomalous enrichment of calcium was observed. Higher valence state of chromium such as Cr⁶⁺(d⁰) was detected in the grain boundaries whereas Cr³⁺(d³) and Cr⁴⁺(d²) were dominant in the bulk. Very fast interdiffusion of alkaline earths was observed in the Sr²⁺-La_0.75Ca_0.25CrO₃ system. All observed phenomena were correlated by assuming the A-site vacancy which may be induced by the formation of Cr⁶⁺ at grain boundaries.     

Tetramethylsuccinonitrile in polyvinyl chloride products for food and its release into food-simulating solvents

Summary The content of tetramethylsuccinonitrile (TMSN), the main decomposition product of 2,2-azobis-isobutyronitrile, in polyvinyl chloride (PVC) products used for food packaging, were examined as well as food-simulating solvents. The TMSN concentration in 17 PVC products ranged from below the detection limit, 0.05 mg/kg, up to 523 mg/kg. The release of TMSN from two PVC products into five kinds of food-simulating solvents at 60 °C for 30 min was observed, except for 1 ± 1 g/kg of TMSN in n-heptane from a PVC bottle containing 523±30.4 mg/kg of TMSN. The detection limit of TMSN in the food-simulating solvents was 1 g/kg. When pieces of the bottle were stored in olive oil at 40 °C for 120 days, 5 ± 1 g/kg of TMSN was detected in the oil. The release of TMSN from the pieces of the bottle into olive oil between 80 and 140 °C depended on the formula 1ny = 0.08786x - 5.696,r = 0.9927, wherey is the concentration (g/kg) of TMSN in olive oil, x is the temperature (°C), andr is the correlation coefficient.

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Tetramethyl-succinonitril in Polyvinylchloridprodukten für Lebensmittel und seine Freisetzung in simulierenden Lösungsmitteln

Zusammenfassung Untersucht wurde der Gehalt von Tetramethyl-Succinonitril (TMSN), dem Hauptzersetzungsprodukt von 2,2-Azobis-iso-butyronitril, in Polyvinylchloridprodukten (PVC) für Lebensmittel im Zusammenhang mit dessen Freisetzung in simulierenden Lösungsmitteln. Die TMSN-Konzentration in 17 PVC-Produkten lag teilweise unterhalb der Meßgrenze; ansonsten lag sie zwischen 0,05 und 523 mg/kg. Ausgenommen von 1 ± 1 g/kg TMSN in n-Heptan aus einer PVC-Flasche, die 523 ± 30,4 mg/kg, TMSN enthielt, wurde bei einer Temperatur von 60 °C innerhalb von 30 min aus zwei PVC-Produkten keine Freisetzung von TMSN in fünf verschiedenen simulierenden Lösungsmitteln beobachtet. Die Erfassungsgrenze von TMSN in den simulierenden Lösungsmitteln lag bei 1 g/kg. Bei Aufbewahrung von Teilen der PVC-Flasche in Olivenöl bei 40 °C für 120 Tage wurden 5 ± 1 g/kg TMSN im Olivenöl erfaßt. Die Freisetzung von TMSN aus der Flasche in das Olivenöl bei Temperaturen zwischen 80 und 140 °C verlief nach der Formel Iny = 0,08786x - 5,696, (r = 0,9927);y = Konzentration (g/kg von TMSN im Olivenöl),x = Temperatur (°C) undr = Korrelationskoeffizient.

     

Estimation of concentrations of antifungal agents allowed as food additives in foods and their daily intake based on official inspection results in Japan in fiscal year 1998

The mean concentrations and daily intake of four antifungal agents were estimated based on the results of an analysis of 7,005 samples of food obtained in official inspections by Japanese local governments in fiscal year 1998. The mean concentration of diphenyl was 0.0004% of the allowable limit, and those of imazalil, o-phenylphenol, and thiabendazole were 14.0%, 3.5%, and 5.7%, respectively. The daily intakes of these antifungal agents per person, estimated from their concentrations and the daily consumption of the foods, were 0.000326, 1.89, 11.5, and 23.3 micrograms, respectively, and assuming a body weight of 50 kg, the amounts of these antifungal agents consumed were 0.000013%, 0.15%, 0.12%, and 0.47% of the acceptable daily intake, respectively. These values are similar to the values obtained on the basis of the results of the official inspection in fiscal years 1994 and 1996, except that the amount of diphenyl is much lower (1/100).     

Effect of transition elements on the properties of MC carbides in IN-100 nickel-based superalloy

The effect of nine transition elements on the morphology, distribution and composition of MC carbides (MCs) in a nickel-base superalloy, IN-100, was investigated by differential thermal analysis (DTA), microstructural observation and X-ray microanalysis. The doping with tantalum, tungsten and molybdenum caused a significant change in the morphology and distribution of MCs as well as the profile of DTA curve of IN-100. The compositions of the MC in IN-100 were TiC and (Ti_0.80Mo_0.17V_0.03) C, and the doping with niobium, tantalum and tungsten changed significantly the composition of MC. On the other hand, the doping with chromium, vanadium, hafnium and zirconium scarcely changed the composition. In addition to TiC and (Ti, Mo, V) C, zirconium- and hafnium-rich MCs were found in the zirconium- and hafnium-doped alloys, respectively. The effect of the dopants on the composition of MCs could be explained by a relationship between the metallic radius and the free energy of formation for the MC.     

A 16-Mb Toggle MRAM With Burst Modes

This paper describes a recently developed 16-Mb toggle magnetic random access memory (MRAM). It has 100-MHz burst modes that are compatible with a pseudo-SRAM even though the toggle cell requires reading and comparing sequences in write modes. To accelerate operating clock frequency, we propose a distributed-driver wide-swing current-mirror scheme, an interleaved and pipelined memory-array group activation scheme, and a noise-insulation switch scheme. These circuit schemes compensate the toggle cell timing overhead in write modes and maintain write-current precision that is essential for the wide operational margin of MRAMs. Because toggle cells are very resistant to write disturbance errors, we designed the 16-Mb MRAM to include a toggle MRAM cell. The MRAM was fabricated with 0.13-mum CMOS and 0.24-mum MRAM processes with five metal layers.