Redistribution of contaminants by a fluctuating water table in a micro-porous, double-porosity aquifer: field observations and model simulations.

Large seasonal fluctuations of the water table are characteristic of aquifers with a low specific yield, including those fractured, double-porosity aquifers that have significant matrix porosity containing virtually immobile porewater, such as the Chalk of northern Europe. Where these aquifers are contaminated, a strong relationship between water table elevation and contaminant concentration in groundwater is commonly observed, of significance to the assessment, monitoring, and remediation of contaminated groundwater. To examine the processes governing contaminant redistribution by a fluctuating water table within the 'seasonally unsaturated zone', or SUZ, profiles of porewater solute concentrations have been established at a contaminated site in southern England.

Study of platelet aggregation in vivo: IV Effect of pyrimido-pyrimidine derivatives.

Two pyrimido-pyrimidine derivatives (RA 233 and VK 744) were found effective aggregation inhibitors in vitro of human and monkey platelets and in vivo in stumptailed monkeys and chimpanzees. They also inhibited thrombotic occlusion of metal screens inserted into arteriovenous shunts.