X-ray specs

摘要

Since they were discovered, x-rays have been used to study biology. They can photograph things light cannot reach and probe the atomic structures of protein molecules. As the aaas learned in a ses sion on the latest x-ray technology, though, they are being pushed further ev ery day. Now they are being used to take three-dimensional pictures of individual cells, to map the distribution of trace ele ments inside cells and to work out hitherto intractable molecular structures.