The molybdenum isotopic composition in river water: Constraints from small catchments

We report molybdenum isotope compositions and concentrations in water samples from a variety of river catchment profiles in order to investigate the influence of anthropogenic contamination, catchment geology, within-river precipitation, and seasonal river flow variations on riverine molybdenum. Our results show that the observed variations in δ98/95Mo from 0‰ to 1.9‰ are primarily controlled by catchment lithology, particularly by weathering of sulfates and sulfides. Erosion in catchments dominated by wet-based glaciers leads to very high dissolved molybdenum concentrations. In contrast, anthropogenic inputs affect neither the concentration nor the isotopic composition of dissolved molybdenum in the rivers studied here. Seasonal variations are also quite muted. The finding that catchment geology exerts the primary control on the delivery of molybdenum to seawater indicates that the flux and isotope composition of molybdenum to seawater has likely varied in the geologic past.

[Prosthetic rehabilitation of a traumatic occlusion due to bulimia nervosa. Case report]

Because of the typical localisation of erosions in anorectic/bulimic patients, the dentist is frequently the first medical person to discern this general illness (anorexia and bulimia nervosa). From the dental viewpoint, the aim should be to preserve sound dental tissue and to prevent further toothwear. A restorative treatment is to be carried out only after causal therapy and after resolving the basic disease. By means of this procedure a good long-term prognosis can be expected. Considering the patient's young age, dentistry should be preservative using the adhesive technique. This case report documents the systematic procedure of the functional and esthetic rehabilitation of an eroded dentition and shows factors essential to the treatment.