MAGNESIUM | De-icing salts help keep our roads safe by preventing ice from freezing on roads and bridge decks. But that safety comes with a price, since the 17 million tons of de-icing salts applied annually to U.S. roadways greatly contribute to their decay. Comparing three different salts, researchers with Purdue’s Joint Transportation Research Program found that all three strongly interacted with the concrete to which they are applied, producing additional phases and phase changes that, when expansive in nature, can cause additional cracking and damage to the concrete. And while magnesium chloride is considered more effective at lower temperatures, sodium chloride appears more benign than either magnesium chloride or calcium chloride when reacting with the concrete substrate.

Understanding Culture from Ancient Dental Enamel

STRONTIUM | Rising at dawn when they hear the mosque’s call for prayer, Michele Buzon and her crew eat a light snack, then head for a burial site more than 3,500 years old. After excavating for a few hours in the northern Sudan desert, they return to their house for breakfast, then dig again until mid-afternoon, when they return home to process findings.

Buzon’s bioarcheology team has traveled to Tombos five winters to examine strontium in the dental enamel of human remains to learn about migration in the Nile Valley, where ancient Nubian and Egyptian cultures once coexisted.

With more than 200 remains excavated from individual and group tombs, they have covered about one-third of the site, says Buzon, associate professor of anthropology.

Differences in strontium ratios, along with skeletal and mortuary analyses, reveal that biologically and ethnically mixed people lived there, fueling insights on sociopolitical activities and biocultural effects of environmental stress and cultural change.

“These people lived good lives. They have relatively few signs of ill health, nutritional deficiencies, infection or signs of hard labor,” she says. “They also show almost no violent injuries in their bones, and appear to have lived in peace in their multicultural community.” | K.M.