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Wave of the future: Terahertz chips a new way of seeing through matter

Electromagnetic pulses lasting one millionth of a millionth of a second may hold the key to advances in medical imaging, communications and drug development. But the pulses, called terahertz waves, have long required elaborate and expensive equipment to use.

Now, researchers at Princeton University have drastically shrunk much of that equipment: moving from a tabletop setup with lasers and mirrors to a pair of microchips small enough to fit on a fingertip.

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5 things you didn’t know about...electric cotton

Jiesheng Ren – Electron microscopy image of the conductive graphene-cotton composite.

1. A new process deposits graphene-based inks to produce a conductive textile made from our most widely used fabric – cotton.

2. This process was developed by the Cambridge Graphene Centre, UK, and Jiangnan University, China.

3. Most current wearable sensors use rigid electronic components mounted on flexible substrates such as plastic films and textiles – these can be uncomfortable to wear and can be damaged when washed. The researchers found that the graphene-coated cotton could reliably detect up to 500 motion cycles, even after more than 10 washing machine cycles.  

4. Graphene also benefits from environmental and economic advantages.

5. Potential areas of application include personal health technology, high-performance sportswear and military apparel.

For more on electric cotton see page 8 of the January issue of Materials World.

Meet the Extremely Rare Pocket Shark

Museum scientists are getting an up-close look at an extremely rare—and extremely small—shark by taking high-resolution, three-dimensional x-ray scans.

National Oceanic and Atmospheric Administration (NOAA) researchers were trawling in the Gulf of Mexico for a sperm whale feeding study in 2010 when they inadvertently pulled up a tiny, odd-looking shark with a bulbous head and rows of sharp teeth. NOAA researchers subsequently identified the creature as the rare pocket shark (Mollisquama sp.). The specimen is only the second ever collected, 36 years after the first one was found off the coast of Chile.

Named for two small openings above its pectoral fins, the pocket shark is still mostly a mystery, as is the purpose its pockets serve. But instead of dissecting this rare 5.5-inch-long specimen, scientists have turned to non-destructive x-ray techniques: computed tomography (CT) scanning in the Museum’s Microscopy and Imaging Facility and at the European Synchrotron Radiation Facility (ESRF) in France.

“The level of detail we can achieve through x-ray imaging is just incredible,” says John Maisey, a curator in the Museum’s Division of Paleontology who has been working with NOAA researchers and Museum Axelrod Postdoctoral Fellow John Denton to scan the specimen. “It allows you to look at these priceless specimens in a way you couldn’t have 10 or 15 years earlier.”

The CT scans proved especially valuable for counting the vertebrae of the pocket shark, the smallest of which were too small to be picked up using standard x-ray imaging, and for counting the teeth. Many of the specimen’s teeth were missing, but by rotating the image of the jaw and examining its inner surface, researchers were able to count the tiny new teeth coming up to take their place.

The species appears to be closely related to cookie cutter sharks, which feed by taking bites out of the skin of larger animals. And the anatomy of the pocket shark’s jaws and teeth indicate that it inhabits a similar ecological niche. 

As for the shark’s mysterious pockets, one working hypothesis is that that they might emit a bioluminescent fluid to either attract mates or to confuse predators. Maisey and Denton are now poring over the extremely high-resolution scans taken at ESRF with Mark Grace, the biologist with NOAA’s Southeast Fisheries Science Center who discovered the specimen, to learn more about their anatomy.  

But anything gleaned from the scans will likely remain hypothetical until scientists can observe a pocket shark in action.

“I would love to see a pocket shark alive in its environment,” Grace says. “But the CT scans are the next best thing.”

This story was originally published on the Museum blog. 

This is a patch of nanoscopic needles that was built to inject DNA and other nucleic acids directly into individual cells. 

The technique, developed by scientists at Imperial College London and Houston Methodist Research Institute, constructs tiny porous groups of needles out of biodegradable silicon. Each needle is 1,000 times thinner than a human hair. The team showed that their innovation could be used to deliver therapeutic nucleic acids inside human and animal cells. 

[The image (above) shows human cells (green) on the nanoneedles (orange). The nanoneedles have injected DNA into the cells’ nuclei (Blue). The image was taken by the researchers using optical microscopy. Image courtesy Chiappini et al./ICL.]

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