Archimedes' hidden treasure
In 1907, Johan Ludvig Heiberg came upon a many centuries-old book in a Constantinople library that contained Greek Orthodox prayers and rites. The book was significant in itself, but on closer inspection using a magnifying glass, Heiberg realized an even greater treasure was hidden below the surface text. What he had discovered were seven treatises by Archimedes in the original Greek, among which is the only known copy of the illustrious mathematician's "Method of Mechanical Theorems."
   The treatises were copied in the 10th century and are the earliest surviving works by Archimedes, who lived in the third century B.C. The writing was washed and scraped off 200 years later by a scribe who reused the pages for a prayer book, creating a twice-used parchment book known as a palimpsest. The later script, also in Greek, ran at a 90-degree angle to the original text, which in places is still discernible to the naked eye. Full story...

Tracking a microscopic 'rocket' by its tail
Using a laser device that allows them to view microscopic movement, biomedical engineering researchers at Johns Hopkins have produced startling new findings about how deadly bacteria spread infection between neighboring cells. Writing in the October 26 issue of Nature, Scot C. Kuo and James L. McGrath describe how Listeria monocytogenes--a common source of poisoning in processed foods--exhibit an unusual stutter-step motion while building rocketlike "tails" that propel them from one living host cell to another. The engineers' discovery contradicts a widely held belief that filaments in these tails grow and push in a smooth continuous motion.
   To study the rocketlike motion of Listeria, the researchers used an innovative tracking device developed by Kuo. The instrument--a laser built into an optical microscope--allowed them to peer inside living cells and record the motion of Listeria microbes, the potentially fatal pathogens that have triggered a number of major processed food recalls in recent years. Full story...

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