Conductivities of Room Temperature Molten Salts Containing AlCl3, Measured by a Computerized Direct Current Method

The conductivities of the binary room-temperature molten salt systems AlCl3-N-n-butylpyridinium chloride (BPC), AlCl3-l-ethyl-3-methylimidazolium chloride (EMIC) and AlCl3-benzyltriethylammo-nium chloride (BTEAC) have been measured at different temperatures and compositions by a d.c. four-probes method. There is a maximum of the conductivity at 50 mol% AlCl3 in the AlCl3-BPC and AlCl3-EMIC systems at 40 to 80 °C, their activation energies being relatively low (20.79 and 14.76 kJ/mol, respec­ tively). As to the A1C13-BTEAC system, there is an irregular change in the conductivity at 40-70 mol% AlCl3 in the temperature range 50 to 80 °C. The conductivities of the three RTMS are in the order AlCl3-EMIC > AlCl3-BPC > AlCl3-BTEAC, the reason being discussed.

Transplacental passage of aluminium from pregnant mice to fetus organs after maternal transcutaneous exposure

Aluminium is present in tap water, antiperspirants and cosmetics up to 20%. Teratogenicity of aluminium was clearly identified after per os or intravenous administra tion. Malformations and other alterations by aluminium intoxication were evaluated in fetus. In the present study, we investigated the possible transplacental passage of aluminium and its accumulation in the tissue after cutaneous uptake. Female Swiss mice received alumi nium chloride by cutaneous way (0.4 μg/day) during 20 days of gestation. The samples were assayed for alumi nium quantification by graphite furnace atomic absorp tion with Zeeman correction. This treatment led to an increase of aluminium in maternal and fetus samples (serum, amniotic fluid and organs) as compared to controls.

Trehalose Protects Yeast Pyrophosphatase against Structural and Functional Damage Induced by Guanidinium Chloride

Trehalose is accumulated at very high concentrations in yeasts when this organism is sub­ mitted to a stress condition. This report approaches the question on the protective effect of trehalose and its degradation product, glucose, against structural and functional damage promoted by guanidinium on yeast cytosolic pyrophosphatase. Here it is shown that both, 1 ᴍ trehalose or 2 ᴍ glucose, are able to attenuate at almost the same extent the conforma­ tional changes promoted by guanidinium chloride on the pyrophosphatase structure. On the other hand, while 1 m trehalose increases 3.8 times the Ki (from 0.15 to 0.57 ᴍ) for guanidi­ nium chloride inhibition of pyrophosphatase activity, 2 m glucose did not even duplicate this parameter (from 0.15 to 0.25 ᴍ). These data support evidences for a functional reason for the accumulation by yeasts of trehalose, and not other compound, during stress conditions.