Sunday, August 25, 2013

The 1,600-Year-Old Goblet and How Romans Were Nanotechnology Pioneers

Researchers have finally found out why the jade-green cup (showed bellow) appears red when lit from behind.
The colorful secret of a 1,600-year-old Roman chalice at the British Museum is the key to a super­sensitive new technology that might help diagnose human disease or pinpoint biohazards at security checkpoints.

«The Romans may have first come across the colorful potential of nanoparticles by accident, but they seem to have perfected it.»

The glass chalice, known as the Lycurgus Cup because it bears a scene involving King Lycurgus of Thrace, appears jade green when lit from the front but blood-red when lit from behind—a property that puzzled scientists for decades after the museum acquired the cup in the 1950s. The mystery wasn’t solved until 1990, when researchers in England scrutinized broken fragments under a microscope and discovered that the Roman artisans were nanotechnology pioneers: They’d impregnated the glass with particles of silver and gold, ground down until they were as small as 50 nanometers in diameter, less than one-thousandth the size of a grain of table salt. The exact mixture of the precious metals suggests the Romans knew what they were doing, «an amazing feat», says one of the researchers, archaeologist Ian Freestone of University College London.

The ancient nanotech works something like this: When hit with light, electrons belonging to the metal flecks vibrate in ways that alter the color depending on the observer’s position. Gang Logan Liu, an engineer at the University of Illinois at Urbana-Champaign, who has long focused on using nanotechnology to diagnose disease, and his colleagues realized that this effect offered untapped potential. «The Romans knew how to make and use nanoparticles for beautiful art», Liu says. «We wanted to see if this could have scientific applications».
When various fluids filled the cup, Liu suspected, they would change how the vibrating electrons in the glass interacted, and thus the color. (Today’s home pregnancy tests exploit a separate nano-based phenomenon to turn a white line pink).

Since the researchers couldn’t put liquid into the precious artifact itself, they instead imprinted billions of tiny wells onto a plastic plate about the size of a postage stamp and sprayed the wells with gold or silver nanoparticles, essentially creating an array with billions of ultra-miniature Lycurgus Cups. When water, oil, sugar solutions and salt solutions were poured into the wells, they displayed a range of easy-to-distinguish colors—light green for water and red for oil, for example. The proto­type was 100 times more sensitive to altered levels of salt in solution than current commercial sensors using similar techniques. It may one day make its way into handheld devices for detecting pathogens in samples of saliva or urine, or for thwarting terrorists trying to carry dangerous liquids onto airplanes.

The original fourth-century C.E. Lycurgus Cup, probably taken out only for special occasions, depicts King Lycurgus ensnared in a tangle of grapevines, presumably for evil acts committed against Dionysus, the Greek god of wine. If inventors manage to develop a new detection tool from this ancient technology, it’ll be Lycurgus’ turn to do the ensnaring.


Thursday, August 8, 2013

Diving in a Cenote (Mayan sacred cave)

A cenote is a deep natural pit or sinkhole, created as result from the collapse of limestone bedrock that exposes groundwater underneath, these natural formations are associated with the Yucatán Peninsula in Mexico and some nearby Caribbean islands.
Cenotes were sometimes used by the ancient Maya for sacrificial offerings, the term derives from a word used by the low-land Yucatec Maya, "Ts'onot" to refer to any location with accessible groundwater. Major Maya settlements required access to adequate water supplies and therefore cities, including the famous Chichén Itzá, were built around these natural wells.
Some cenotes, like the Sacred Cenote in Chichén Itzá, played an important role in Mayan rites, it was believed that these pools were gateways to the afterlife, so no surprise why mayans sometimes used to threw valuable items into them.
The discovery of golden sacrificial artefacts and skeletons in some cenotes led to the archaeological exploration in the first part of the 20th century.

The Hearts of Age - Orson Welles First Film (1934)

The Hearts of Age is an early film made by Orson Welles (best known as director of Citizen Kane). The film is an eight-minute short, which he co-directed with his friend William Vance in 1934. The film stars Welles' first wife, Virginia Nicholson, and Welles himself (interpreting Death). He made the film while still attending the Todd School for Boys in Woodstock, Illinois, at the age of 19.
The plot is a series of images loosely tied together, and is arguably influenced by surrealism.