Behaviour of several solid adsorbents for sampling tetraalkyllead compounds in air

The behaviour of various solid adsorbents for collecting tetraalkyllead compounds has been studied. A synthetic atmosphere containing a known concentration of tetraethyllead was produced and the tetraethyllead compound was trapped in a glass tube containing the solid adsorbent. The trapped compound was extracted with hexane in an ultrasonic bath, and the resulting solution was analysed by GC-MS. Porapak and Tenax, with retention efficiencies of 92 and 96%, respectively, were shown to be the more efficient at trapping this alkyllead compound than Chromosorb, active charcoal, Amberlites and polyurethane foam. The behaviour of both Porapak and Tenax for trapping other tetraalkyllead compounds in the presence of gasoline vapour was also studied.     

Fluctuations in Derrida's random energy and generalized random energy models

The fluctuations of the finite-size corrections to the free energy per site of the random energy model (REM) and the generalized random energy model (GREM) are investigated. Almost sure behavior for the corrections of order (logN)/N is given. We also prove convergence in distribution for the corrections of order 1/N.     

Single wino production ine + e − collisions

We present a detailed analysis of single wino production ine ⁺ e ^? collisions. We give total and differential cross sections at three different energies, relevant to present (DESY) and future (LEP) experiments for different choices of sparticle masses. We comment on different approximations (useful at different energy regimes) and discuss on signatures and backgrounds.     

Characterization by Total Reflection X-ray Fluorescence Spectrometry of filtered water into the cave under the Sun Pyramid in Teotihuacan City

Teotihuacan (50 km north-east Mexico City) was the most important ancient city in Mesoamerica and it flourished 200–750 AC. It is situated in the central part of the Valley of Teotihuacan, in Central México. This study was carried out in the 102 m-long cave under the largest single construction, the massive Sun Pyramid, being located on the east side of the “Avenue of the Dead”, in the northern half-part of the city. The study shows the results of Total Reflection X-ray Fluorescence Spectrometry analysis and other techniques of a water sample obtained from the inside of the cave. The inside temperature ranged between 19 and 22 °C; relative humidity was between 98 and 99.3%; water-dropping velocity (water de-sorption capability) was 13.5 μL min^− 1. Water samples from wells around the site were analyzed too. Metal concentration in all of the water samples matches the characteristics of the sampling site, well's depth, soil and minerals.     

Effect of acid steam explosion on enzymatic hydrolysis ofO. nervosum andC. cardunculus

Applied Biochemistry and Biotechnology -     

Simultaneous determination of morphine and monoamine transmitters in a single mouse brain

A simple procedure for the simultaneous determination of morphine and monoamine transmitters was developed. The procedure consisted of (1) n-butanol extraction and (2) separation and quantitative determination by means of high-performance liquid chromatography combined with electrochemical detection. The maximum intracerebral concentration (210 +/- 35 ng/g wet tissue) of morphine was detected 30 min after intramuscular injection (10 mg/kg), which agreed with previous research. Noradrenaline was significantly decreased by morphine injection, while dopamine and 5-hydroxytryptamine were unchanged. However, 3-methoxytyramine, a metabolite of dopamine, was increased, suggesting that the drug increased the turnover rate of dopamine. The procedure used revealed a direct correlation between pharmacokinetics (e.g., distribution of morphine) and pharmacodynamics (e.g. changes of monoamine concentrations) of the drug in vivo.