Ag6Mo10O33 — a new silver ion conducting ammonia sensor material

Electrical and gas sensing properties of Ag₆Mo₁₀O₃₃ are investigated for the first time. Wagner’s polarization experiment carried out on this material shows that it is a good silver ion conductor in the temperature range of 533 to 657 K. Studies show that it possesses good selectivity and sensitivity towards ammonia with fast response and retrac times indicating its potential as a sensor material for this gas below its TLV value. Morphological changes associated with this compound when exposed to ammonia are studied by using SEM and the corresponding compositional changes associated with each grain is studied by using EDAX. The results indicate that the compound breaks down when exposed to ammonia. When equilibrated with air the reaction products recombine fast to form the original compound. Paper presented at the 2nd International Conference on Ionic Devices, Anna University, India, Nov. 28–30, 2003.     

Isolation and evaluation of cytogenetic effect of Brahmi saponins on cultured human lymphocytes exposed in vitro

Major saponins of Brahmi (Bacopa monniera, Fam: Scrophulariaceae) – bacosides A and B – were isolated from the total methanol extract and characterised based on melting point, TLC, IR, ¹H NMR and ¹³C NMR. They were evaluated for their in vitro cytogenetic effects on human peripheral blood lymphocytes by chromosomal aberration (CA) assay and sister chromatid exchange (SCE) assay. The frequency of chromatid type aberrations and reciprocal interchanges between sister chromatids in the treated cells was scored in comparison to the untreated control. At 30 μg/mL dose, bacoside A showed a statistically significant increase in the frequency of both CA and SCE and bacoside B showed an increase only in SCE. Our report of the genotoxicity of the saponins is significant in view of the reports of anticancer activity of Brahmi extracts.