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Limpet teeth consists of the strongest biological material ever tested

Limpet teeth consists of the strongest biological material ever tested | Science | Scoop.it

Limpets use a tongue bristling with tiny teeth to scrape food from rocks and also to carve out scars, which they nestle in when the tide goes out. The teeth are made of a mineral-protein composite, which the researchers tested in tiny fragments in the laboratory. They found it was stronger than spider silk, as well as all but the very strongest of man-made materials. The findings, published in the Royal Society's journal Interface, suggest that the secret to the material's strength is the thinness of its tightly-packed mineral fibers - a discovery that could help improve the man-made composites used to build aircraft, cars and boats, as well as dental fillings.


"Biology is a great source of inspiration as an engineer," said the study's lead author Dr Asa Barber, from the University of Portsmouth. "These teeth are made up of very small fibers, put together in a particular way - and we should be thinking about making our own structures following the same design principles." Those fibers, consisting of an iron-based mineral called goethite, are laced through a protein base in much the same way as carbon fibers can be used to strengthen plastic. The teeth themselves are less than a millimeter long, but Dr Barber and his colleagues ground ten of them into a tiny dog-bone shape in order to precisely measure the composite's tensile strength: the amount of force it can withstand before breaking.


The middle part of these samples was more than 100 times thinner than a human hair. With either end glued to specialized levers inside a device called an atomic force microscope, the engineers applied a pulling force to each of these milled tooth samples, until they snapped. The strength they calculated for the tooth material was, on average, about 5 GPa - some five times greater than most spider silk.


This sets a new record for biology, Dr Barber said, even when his team considered the most unusual spiders. People are always trying to find the next strongest thing, but spider silk has been the winner for quite a few years now," he explains. "So we were quite happy that the limpet teeth exceeded that.


"One of my colleagues on the paper, from Italy, found some exotic spider silk that was about 4.5 GPa, and we measured about 5 GPa."

This measurement is about the same as the pressure needed to turn carbon into diamond beneath the earth's crust. Alternatively, as Dr Barber explained, it can be compared to a single string of spaghetti holding up 3,000 half-kilogram bags of sugar. In terms of man-made materials, the limpet tooth is stronger than Kevlar fibers and almost as good as the best high-performance carbon fiber materials.


Via Dr. Stefan Gruenwald
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Complex nerve-cell signaling traced back to common ancestor of humans and sea anemones

Complex nerve-cell signaling traced back to common ancestor of humans and sea anemones | Science | Scoop.it

New research shows that a burst of evolutionary innovation in the genes responsible for electrical communication among nerve cells in our brains occurred over 600 million years ago in a common ancestor of humans and the sea anemone. The research, led by Timothy Jegla, an assistant professor of biology at Penn State University, shows that many of these genes, which when mutated in humans can lead to neurological disease, first evolved in the common ancestor of people and a group of animals called cnidarians, which includes jellyfish, coral, and sea anemones.


"Our research group has been discovering evidence for a long time that most major signaling systems in our neurons are ancient, but we never really knew when they first appeared," Jegla said. "We had always assumed that we would be able to trace most of these signaling systems to the earliest nervous systems, but in this paper we show that this is not the case. It looks like the majority of these signaling systems first appear in the common ancestor that humans share with jellyfish and sea anemones."

Electrical impulses in nerve cells are generated by charged molecules known as ions moving into and out of the cell through highly specialized ion-channel proteins that form openings in the cell membrane. The new research focuses on the functional evolution of the genes that encode the proteins for potassium channels -- ion channels that allow potassium to flow out of nerve cells, stopping the cell's electrical impulses. "The channels are critical for determining how a nerve cell fires electrical signals," said Jegla. "It appears that animals such as sea anemones and jellyfish are using the same channels that shape electrical signals in our brains in essentially the same way."


"Humans and sea anemones went their separate ways evolutionarily speaking roughly 600 million years ago," said Jegla, "so we know that the mechanisms we use to generate impulses in our neurons must be at least that old."


Recent genome sequences from comb jellies, which also have nervous systems, show that they are a more ancient group of animals than sea anemones and might even be the oldest type of animals that are still living today. "When we looked at comb jellies, we found that the potassium channels looked very different -- most of the channel types found in humans were missing," said Jegla. "We could trace only one kind of the human potassium channels that we looked at all the way back to comb jellies, but we find almost all of them in sea anemones."


Via Dr. Stefan Gruenwald
Untapped Events's insight:

 Investigação demonstra que os mecanismos que os nossos neurónios usam para gerar impulsos terá cerca de 600 milhões de anos.


Research shows that the mechanisms we use to generate impulses in our neurons must be at least 600 million years old.


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When's the Best Day and Time to Post on Social Media?

When's the Best Day and Time to Post on Social Media? | Science | Scoop.it

Your social analytics can give you an indication of when your audience is engaging with your content, and there are tons of blog posts out there offering you sound advice on when you should post your content on social media. But it’s not enough to just know when your visitors are online, but when they’re engaging online (i.e. clicking, sharing, emailing, and even printing).

We took a look at our proprietary data based on 14 million sites using our tools worldwide (that’s about 3 billion pageviews a day), to help you optimize when you should post your content, including the day, time, and social network. Here’s what we found for Facebook, Twitter, LinkedIn, and Pinterest.

 

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Geologists solve the mystery of what tectonic plates float on

Any geologist will tell you the Earth’s crust is broken into tectonic plates that “float” around like gigantic rafts. But just what these rafts have been floating upon, has been a mystery – until now. A team of New Zealand scientists detonated tons of dynamite and listened for echoes to reveal the underbelly of the Pacific plate. They found a 10 kilometre thick channel of lubricating jelly-like rock, which they say allows the plate to slide above it, according to a report in Nature.


German meteorologist Alfred Wegener proposed the idea of rafting continents back in 1912 after perusing maps and noticing that the east coast of South America and the west coast of Africa would fit together like jigsaw pieces.


But scientists only started taking the idea seriously in 1963when geophysicists Fred Vine and Drummond Matthews showed that the crust on the ocean floor, on either side of the mid-oceanic ridges, was indeed moving.


These days plate tectonics is “obvious”, says Louis Moresi, a geologist at the University of Melbourne. “You can log on to Google Earth and actually plot the movement.” The plates themselves are composed of a thick layer of hard rock known as the lithosphere that lies above a softer layer known as the asthenosphere. But no one knew what lay at the lithosphere asthenosphere boundary (LAB).


In the past geologists relied on earthquakes originating on the other side of the planet of the planet to try and find out. Like doctors placing a stethoscope to the Earth’s surface, they detected seismic waves. The fact these waves move at different speeds through different layers allowed geologists to sketch a coarse picture of the medium through which they travelled. But natural seismic waves are 10-40 kilometers in length – too long to resolve the fine-grained structure below the plates. So the New Zealanders took matters into their own hands.


“Rather than relying on earthquake waves that come from below we create our own ‘earthquakes’ with dynamite shots,” says Tim Stern at Victoria University, Wellington, who led the project. The resulting waves are about 500 metres long and  able to resolve finer structures. The blast zone was sited on the southern tip of New Zealand’s North Island where the 73-kilometre thick Pacific plate dips beneath the Australian plate at the rate of about 40 millimetres a year.


The team set up 877 Coke can-sized seismometers strung like beads along 85 kilometers. Then from multiple boreholes they detonated half a ton of TNT in each. The seismic echoes revealed something unusual stuck to the Pacific plate’s underbelly – a channel of jelly-like rock about 10 kilometers thick.


Via Dr. Stefan Gruenwald
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Disabled seize life with hand of a superhero

Disabled seize life with hand of a superhero | Science | Scoop.it

The proliferation of 3D printers has had an unexpected benefit: The devices, it turns out, are perfect for creating cheap prosthetics.

 

The fingers are closed by flexing the wrist, which pulls on cable "tendons". Move the wrist again, and the hand opens. The hands are printed in pieces, which are assembled by volunteers, or by parents and children themselves.

 

More than 50 groups, such as Boy Scout and Girl Scout troops and schools like Convent of the Sacred Heart in Manhattan, have created hands for about 500 children.

 

"We have several thousand people on our site who are asking to help make hands," said Schull, a research scientist at the Rochester Institute of Technology. "What could be more rewarding than using your 3D printer to make a hand for someone?"

 
Via Sepp Hasslberger
Untapped Events's insight:

Eu nem sabia bem o que era uma impressora 3D, mas ao perceber que pode ser útil desta forma, penso que pode ser bastante inovador e uma boa forma de ajudar quem mais necessita.

 

I wasn't really aware of what 3D printers were, but after reading this article, I'm more conscious about its potencial: helping people.

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Sepp Hasslberger's curator insight, February 17, 2015 4:33 PM

There goes the business of making expensive prosthetics. Just print your own for a few dollars worth of material and some access time on a 3D printer...

Mytchel Daley's curator insight, March 26, 2015 4:04 AM

Another result of 3D printing but more on he side of the future technology of medical advances. With these devices people who have medical conditions such as being paralyzed in the hand will be able to function the same.