Impact of DNAPL contact on the structure of smectitic clay materials.

Smectitic clays have a flexible structure that may be impacted by contact with dense nonaqueous phase liquids (DNAPLs) present at hazardous waste sites. Measurements of the basal spacing of air-dry clays contacted with pure chlorinated solvents and chlorinated DNAPL wastes showed that the intraparticle spacing is similar to that in air. Basal spacings of water-saturated clays contacted with pure chlorinated solvents are similar to those in contact with water, even after extended equilibration times (300 d).

Systemic manifestations during eruption of primary teeth in infants.

Purpose: The purpose of this study was to describe the most frequent objective clinical manifestations found during the eruption of primary teeth and to assess the correlation between those symptoms and the eruption of various groups of teeth.

Methods: The study was conducted in the Clinica Infantil Colsubsidio in Bogota, Colombia. Five hundred and eighty-five children participated in the study.