The crystal structures of the chiolite-related room temperature phases α-Na5M3F14 (MIII=Cr,Fe,Ga) are determined. For all of them, the space group is P21/n, Z=2; a=10.5096(3) Å, b=7.2253(2) Å, c=7.2713(2) Å, β=90.6753(7)° (M=Cr); a=10.4342(7) Å, b=7.3418(6) Å, c=7.4023(6) Å, β=90.799(5)° (M=Fe), and a=10.4052(1) Å, b=7.2251(1) Å, c=7.2689(1), β=90.6640(4)° (M=Ga). Rietveld refinements produce final RF factors 0.036, 0.033, and 0.035, and RWP factors, 0.125, 0.116, and 0.096, for MIII=Cr, Fe, and Ga, respectively. The MF6 polyhedra in the defective isolated perovskite-like layers deviate very few from perfect octahedra. Subtle octahedra tiltings lead to the symmetry decrease from the P4/mnc space group adopted by the Na5Al3F14 chiolite aristotype to the P21/n space group adopted by the title series. Facile twinning precluded till now the precise characterization of these compounds.

Sodium fluoride (NaF) is an anion that has been previously shown to block the moulting process of Ascaris suum larvae. This study describes moulting and development-specific protein expression profiles of A. suum lung-stage L3 (AsLL3) following NaF exposure. AsLL3s cultured in the presence or absence of NaF were prepared for protein analysis using two-dimensional (2D) electrophoresis. NaF exposure inhibited at least 22 proteins in AsLL3 compared with moulted larvae (i.e. AsLL4). A further comparison of AsLL4 with those of pre-cultured AsLL3 and NaF-exposed AsLL3 revealed 8 stage-specifically and 4 over-expressed proteins. Immunoblot analysis revealed an inhibition by NaF of 19 immunoreactive proteins. Enzyme assay and immunochemical data showed an inhibition of the moulting-specific inorganic pyrophosphatase activity by 41% and a decreased expression in NaF-treated larvae, indicating its significance in the moulting process. A protein spot associated with NaF inhibition was isolated and identified by peptide mass spectrometry and bioinformatics approaches to be a member of 3–hydroxyacyl–CoA dehydrogenase/short-chain dehydrogenase enzyme families. These results have implications for the identification of proteins specific to the moulting process as potential chemotherapeutic targets.

The effect of fluoride on the food and dietary water intake and utilisation were studied in final instars of silkworm, Bombyx mori L. race NB4D2 fed ad libitum with mulberry leaves treated with sodium fluoride at concentrations of 25 ppm, 50 ppm and 75 ppm. The larval duration increased by two days while food consumption, assimilation rate, assimilation efficiency, feeding and metabolic rates increased significantly in all the treated larvae. On the other hand, the amount of faeces produced, food conversion, conversion rate and conversion efficiencies decreased significantly in all the treated batches when compared to controls. The water intake and utilisation parameters increased significantly while rate of water loss through faeces, water retained in the body and retention efficiency decreased in all the fluoride-treated silkworms. The factors responsible for these changes in treated batches are discussed in relation to the effect of fluoride on cocoon and shell weights.

The effect of drinking water fluoridation on the prevalence of clinical otoscierosis was investigated in an area where the natural waters have a very low fluoride content. The methods included a retrospective chart review and a residential history questionnaire. Only subjects born between 1948 and 1962 were included. In this age group, the prevalence of clinical otosclerosis was found to be 0.35 per cent of persons exposed to fluoridated tap water and 0.32 per cent of those consuming fluoride-poor water. It seems that a sodium fluoride intake of 1 to 3 mg daily cannot prevent the development of clinical otosclerosis in a lowfluoride area.