Believe It or Not the Scariest Mouth in the World Belongs to a Species of Turtle

Here’s one species of turtle you don’t want to kiss. Believe me, the Leatherback Sea Turtle might look adorable and harmless, but lurking behind its cute face is a set of killer teeth, making its mouth one of the scariest in the world.. Hundreds of these jagged stalactite-like teeth called ‘papillae’ line the turtle’s mouth and esophagus, all the way down to the gut. You just have to see it to believe it.

The Leatherback is the third largest living reptile in the world, and also the largest turtle. It’s actually a pretty docile creature, with a diet mainly consisting of jellyfish. In fact, the only reason it gets so huge is because it eats an astonishingly large number of the slow-moving jellies. Sometimes, the leatherback can consume about 73 percent of its own body weight in a single day, which is about 16,000 calories and three to seven times more than it needs to survive. Talk about binge eating!

So why does this jelly-eating machine need a set of killer teeth, you ask? Well, the teeth gives it an evolutionary advantage. The sharp, pointy, backward-facing papillae actually prevent the slippery jelly from escaping by floating back out of the mouth. This means that the leatherback is able to eat all kinds of jellies – right from the smallest swarms to the most massive ones like the Lion’s Mane Jelly. This turtle species also has an unusually long esophagus that extends way past its stomach and all the way to the rear. Then it loops back up to connect to the stomach. So it’s like a conveyor belt designed to catch, store and continuously process food.

When a baby leatherback first makes an appearance in the world, it is just a tiny hatchling about 3-inches long. But thanks to all the water-rich jellies it consumes in its lifetime, it can grow to an average of four to six ft. long. Now, if you’re thinking that the humungous turtle does nothing but eat and laze around all day, you’re wrong. The leatherback turtle is a migratory species, travelling over 10,000 miles a year. It needs all the energy it can get to cover such large distances. And since jellyfish aren’t exactly energy-boosting foods, the leatherback’s best bet is to stuff its face with as many jellies as it can manage in one go.

Unfortunately, despite its brilliantly designed digestive system, the leatherback is unable to differentiate between jellyfish and plastic trash floating in the water that gets stuck in its huge papillae. This is becoming a huge cause of concern as the fascinating creature is facing extinction. Serious efforts are made to preserve the species and I sure do hope they succeed.

NASA’s Hubble Finds Supernova Star System Linked to Potential “Zombie Star”

The two inset images show before-and-after images captured by NASA’s Hubble Space Telescope of Supernova 2012Z in the spiral galaxy NGC 1309. The white X at the top of the main image marks the location of the supernova in the galaxy.

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Using NASA’s Hubble Space Telescope, a team of astronomers has spotted a star system that could have left behind a “zombie star” after an unusually weak supernova explosion.

A supernova typically obliterates the exploding white dwarf, or dying star. On this occasion, scientists believe this faint supernova may have left behind a surviving portion of the dwarf star -- a sort of zombie star.

While examining Hubble images taken years before the stellar explosion, astronomers identified a blue companion star feeding energy to a white dwarf, a process that ignited a nuclear reaction and released this weak supernova blast. This supernova, Type Iax, is less common than its brighter cousin, Type Ia. Astronomers have identified more than 30 of these mini-supernovas that may leave behind a surviving white dwarf.

“Astronomers have been searching for decades for the star systems that produce Type Ia supernova explosions,” said scientist Saurabh Jha of Rutgers University in Piscataway, New Jersey. “Type Ia’s are important because they’re used to measure vast cosmic distances and the expansion of the universe. But we have very few constraints on how any white dwarf explodes. The similarities between Type Iax’s and normal Type Ia’s make understanding Type Iax progenitors important, especially because no Type Ia progenitor has been conclusively identified. This discovery shows us one way that you can get a white dwarf explosion.”

The team’s results will appear in the Thursday, Aug. 7 edition of the journal Nature.

The weak supernova, dubbed SN 2012Z, resides in the host galaxy NGC 1309 which is 110 million light-years away. It was discovered in the Lick Observatory Supernova Search in January 2012. Luckily, Hubble’s Advanced Camera for Surveys also observed NGC 1309 for several years prior the supernova outburst, which allowed scientists to compare before-and-after images.

Curtis McCully, a graduate student at Rutgers and lead author of the team’s paper, sharpened the Hubble pre-explosion images and noticed a peculiar object near the location of the supernova.

“I was very surprised to see anything at the location of the supernova. We expected  the progenitor system would be too faint to see, like in previous searches for normal Type Ia supernova progenitors. It is exciting when nature surprises us,” McCully said.

After studying the object’s colors and comparing with computer simulations of possible Type Iax progenitor systems, the team concluded they were seeing the light of a star that had lost its outer hydrogen envelope, revealing its helium core.

The team plans to use Hubble again in 2015 to observe the area, giving time for the supernova’s light to dim enough to reveal any possible zombie star and helium companion to confirm their hypothesis.

“Back in 2009, when we were just starting to understand this class, we predicted these supernovae were produced by a white dwarf and helium star binary system,” said team member Ryan Foley of the University of Illinois at Urbana-Champaign, who helped identify Type Iax supernovae as a new class. “There’s still a little uncertainty in this study, but it is essentially validation of our claim.”

One possible explanation for the unusual nature of SN 2012Z is that a game of seesaw ensued between the bigger and smaller of the star pair. The more massive star evolved more quickly to expand and dump its hydrogen and helium onto the smaller star. The rapidly evolving star became a white dwarf. The smaller star bulked up, grew larger and engulfed the white dwarf. The outer layers of this combined star were ejected, leaving behind the white dwarf and the helium core of the companion star. The white dwarf siphoned matter from the companion star until it became unstable and exploded as a mini-supernova, leaving behind a surviving zombie star.

Astronomers already have located the aftermath of another Type Iax supernova blast. Images were taken with Hubble in January 2013 of supernova 2008ha, located 69 million light-years away in the galaxy UGC 12682, in more than four years after it exploded. The images show an object in the area of the supernova that could be the zombie star or the companion. The findings will be published in The Astrophysical Journal.

“SN 2012Z is one of the more powerful Type Iax supernovae and SN 2008ha is one of the weakest of the class, showing that Type Iax systems are very diverse,” explained Foley, lead author of the paper on SN 2008ha. “And perhaps that diversity is related to how each of these stars explodes. Because these supernovae don’t destroy the white dwarf completely, we surmise that some of these explosions eject a little bit and some eject a whole lot.”

The astronomers hope their new findings will spur the development of improved models for these white dwarf explosions and a more complete understanding of the relationship between Type Iax and normal Type Ia supernovae and their corresponding star systems.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington.

Rosetta is now in orbit around a comet

Rosetta is the first spacecraft to rendezvous with a comet.

Comets have spun in and out of human history as celestial omens of death and catastrophe for millennia. It was only in the sixteenth century that comets began to be investigated as astronomical bodies. The physical nature of comets as cosmic snowballs of frozen gases, rock and dust was only confirmed recently.

Now, after decades of dreaming and preparation, scientists have finally put a spacecraft into orbit around a comet.

Rosetta launched in 2004 and has travelled 405 million kilometres from Earth (which is about halfway between the orbits of Jupiter and Mars) to arrive at comet 67P/Churyumov-Gerasimenko on 6 August 2014.

 “After 10 years, five months and four days travelling towards our destination, looping around the Sun five times and clocking up 6.4 billion kilometres, we are delighted to announce finally ‘we are here’,” says Jean-Jacques Dordain, ESA’s Director General.

Rosetta and the comet are rushing through space at 55 000 km per hour.

Since leaving Earth, Rosetta has taken a convoluted route; it made three flybys of Earth and one of Mars and passed by asteroids Šteins and Lutetia, taking the first ever close-up shots of these astronomical objects. A successful orbit was achieved only after a series of 10 flybys of the comet, all of which had to be perfectly accurate.

The comet is on a 6.5-year orbit of the Sun and Rosetta will join it on its journey for just over a year before spinning close to the Sun and then out towards Jupiter. 

Scientists' interest in comets springs from comets' role as a “seed” of life on Earth and as primitive building blocks of the Solar System.

“Today’s achievement is a result of a huge international endeavour spanning several decades,”says Alvaro Giménez, ESA’s Director of Science and Robotic Exploration.

“We have come an extraordinarily long way since the mission concept was first discussed in the late 1970s and approved in 1993, and now we are ready to open a treasure chest of scientific discovery that is destined to rewrite the textbooks on comets for even more decades to come.”

The Visible and Infrared Thermal Imaging Spectrometer, VIRTIS, aboard Rosetta showed that the comet’s temperature was –70ºC, which told scientists that the surface would be “dark and dusty rather than clean and icy”.

Rosetta is now 100 km from the comet but over the next six weeks it will approach even closer. Scientists aim to land Philae, a part of the spacecraft, on the surface of the comet in November.

Landing a craft on a comet is tricky, to say the least. If the chosen spot does not get the perfect amount of sunlight then the craft risks either not being able to recharge or overheating.

The Rosetta has 11 instruments to study the comet and will measure the gravity, mass, density, internal structure and shape, among other characteristics.

New super-powerful, brain-mimicking computer chip unveiled

A new type of computer chip uses 'cognitive computing' to give supercomputer performance to electric cars and smartphones. It also runs on the same amount of power as a simple hearing aid.

Invented by researchers at IBM, the entirely new type of chip has been called ‘neurosynaptic’, because it responds to changes in the environment just like our brains do. "We have taken inspiration from the cerebral cortex to design this chip," IBM chief scientist for brain-inspired computing, Dharmendra Modha, told Rob Lever at Phys.org.

Unlike existing chips, that are essentially number-crunching calculators, these new computer chips can respond to the sights, smells and sounds from the environment around them to ‘learn’ and respond to different situations. They do this by using an expansive network of silicon transistors, one billion of which act like neurons and 256 million of which act like synapses in the human brain. "What that means, essentially, is that the chip can encode data as patterns of pulses, which is similar to one of the many ways neuroscientists think the brain stores information," says Daniela Hernandez at Wired.

The chip also boasts 4,096 cores and a total of 5.4 billion transistors, and it's barely the size of a postage stamp. To put that in perspective, the first generation of this chip was released in 2011, and it had just one core and 262,144 synapses. And that was hailed as revolutionary at the time.

The applications of this chip appear to be many, Modha told Phys.org, saying that it "has the potential to transform society" with a new generation of computing technology. Applications include installing the chip into an electric car so it can use the sensory information around it to see an accident before it happens and alert the driver. It could also give a smartphone the ability

Cigarette butts can be converted into electrical parts

Researchers in South Korea have converted used cigarette butts into an electrical component for use in smartphones, computers and electric cars. 

Globally, we’re throwing out around 5.6 trillion cigarette butts every year, and they’re both toxic and non-biodegradable. But what if we could convert all of this waste into something useful?

A team of researchers from the Seoul National University has discovered that cigarette butt material - cellulose acetate fibre - can be made into a coating needed to produce a device known as a supercapacitor. Supercapacitors are powerful components used in many different kinds of electronics to store large amounts of electrical energy. They’re used for backing up batteries in computers and smartphones, and for storing renewable energy in electric cars and wind turbines. Needless to say, we're going to need to produce a lot of supercapacitors in the foreseeable future, so why not tap into the 766,571 metric tonnes of cigarette butts that are disposed of globally every year?

"Numerous countries are developing strict regulations to avoid the trillions of toxic and non-biodegradable used-cigarette filters that are disposed of into the environment each year,” said the study's co-author, physicist Jongheop Yi, in a press release. “Our method is just one way of achieving this."

The team converts the fibres in the cigarette butts into a useable substance through a special burning technique known as pyrolysis. Pyrolysis punches a series of tiny pores into the fibre, which gives it the large surface area it needs to increase the performance of the supercapacitor. "A combination of different pore sizes ensures that the material has high power densities, which is an essential property in a supercapacitor for the fast charging and discharging,” the researchers said.

Publishing in the journal Nanotechnology, the team reports that their new cigarette butt material can store a higher amount of electrical energy than the carbon-based material that's currently being used by supercapacitor manufacturers to do the job.

This is how spiders spin silk for their webs

Researchers have uncovered the mechanism that allows spiders to build such strong webs.

One of the world’s strongest materials, spider silk, has baffled scientists for centuries. It’s lightweight, stretchy, stronger than steel, and produced by spiders using water as a solvent, but how do these animals produce this fibre?

It all comes down to silk proteins known as spidroins, which are made of about 3,500 organic compounds known as amino acids. Spiders store spidroins as soluble proteins in their silk glands. But, when they are about to use them to spin their web, the structure of the spidroins changes as it exits the spider's silk gland, becoming solid fibers.

Scientists from the Swedish University of Agricultural Science and the Karolinska Institute have found that the spindroins reach an acidic pH level of about 5.7 inside the glands when the spider is making its web. They also found a higher concentration of bicarbonate ions inside the gland when the web is being spun. 

According to their research, both ends of the spider's silk grand have different pH levels, which helps these proteins become a solid fibre that can be spun into a solid web. They also found that the pH level has different effects on the stability of the two regions at each end of the spindroin proteins. “While one of the ends tended to pair up with other molecules at the beginning of the duct (N-terminal) and became increasingly stable as the acidity increased along the duct, the other end (C-terminal) destabilised as the acidity increased, and gradually unfolded until it formed the structure characteristic of silk at the acidic pH of 5.5”, explained the researchers in a press release.

Published in the journal PLoS Biology, the study suggests a new ‘lock and trigger’ model for spider silk formation, explaining how the material forms so quickly within the spinning duct of the spiders.

Cancer experts predict the end of chemotherapy in 20 years

Scientists in the UK have declared that more effective cancer treatments will soon replace chemotherapy thanks to a world-first project to find the genes responsible for this complex disease.

The four-year project is being run by a team of researchers at Genomics England - owned by the UK Department of Health - who will work alongside researchers from several universities across Britain, the Wellcome Trust, the Great Ormond Street Hospital, and the UK’s Medical Research Council. 

Some 75,000 volunteers from London, Cambridge, and Newcastle with cancer and rare diseases will offer up their genetic material for sequencing over the next few years. Both their healthy and cancer-affected cells will have their DNA mapped as part of the project, and their close relatives will also have their genomes sequenced for comparison.

According to the BBC, the first genome was sequenced on the 30th May this year, and the team has just now passed the 100 genome mark. They aim to have 1,000 genomes sequenced by the end of the year, and if all goes to plan, they will have 10,000 genomes sequenced by the end of 2015. 

"Twenty years from now there will be therapies, instead of chemo, that will be a much more targeted approach to treatment," the head of the Wellcome Trust, Jeremy Farrer, told the press. "Understanding humanity's genetic code is not only going to be fundamental to the medicine of the future, it is an essential part of medicine today. In rare congenital disease, in cancer and in infections, genomic insights are already transforming diagnosis and treatment.”

The team expects that the $US545 million project will allow for the development of new, more effective treatments for cancer and other diseases. These new treatments are also expected to be less invasive than chemotherapy, and cause less severe side-effects. An example of this type of treatment, says Sarah Knapton at the Telegraph, is Herceptin, which is a new drug that's been specifically designed for women suffering from a particular type of breast cancer caused by increased activity of the HER2 gene.
"Strict confidentiality rules will be enforced, and under normal circumstances, patients will not be told of unforeseen surprises that might effect their health - or insurance premiums," says Knapton. "But helpful findings will be fed back to the doctors in charge of their treatment."

Would you give this robot a ride?

A talking robot is hitchhiking its way across Canada as part of a human-robot interaction study that will shine a light on whether robots can trust humans.

Researchers in Canada have used different household products to create a friendly robot that needs humans help to achieve its task: hitchhike across Canada. 

Roboticist Frauke Zeller from Ryerson University and communications expert David Smith from McMaster University, both in Canada, created the hitchBot as part of a social experiment that aims to answer the question “can robots trust humans?”

hitchBot is as tall as the average six-year-old, can speak and hold a conversation—apparently the robot loves to talk about astrophysics—has a hitchhiking hand, and wears yellow wellies. Its face is made out of LED lights, which gives it a range of facial expressions, and its body is wrapped in solar panels. hitchBot, however, can't walk and has to be carried every time someone stops to pick it up from the road.

Once the 'cute' robot meets its new human companion, it will tweet its location and ask for permission to take pictures and post them on Facebook and Instagram. And when it needs recharging, it will ask its human companion to plug it into the cigarette lighter in the cars—and so far no one has said no. The robot's adventure began on July 27.

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“This is both an artwork and a social robotics experiment,” explained Zeller and Harris in a press release. “Usually, we are concerned whether we can trust robots, e.g. as helpers in out homes. But this project takes it the other way around.”

hitchBot ‘wrote’ as part of his online bio:

"I’m excited and a bit nervous about whether people will pick me up or if they will be nice to me along the way. I don’t have a specific route and I’m not sure how long it will take but I’m up for the adventure." 

Discover how hitchBot works in the video below:

http://vimeo.com/100845249

Here's why the Sun's atmosphere is so much hotter than its surface

Scientists at NASA have produced the strongest evidence yet to explain why the Sun’s atmosphere is several hundred times hotter than its surface. 

The surface of the Sun, called the photosphere, has a temperature of around 5,505 °C (9,941 °F). But the Sun’s external atmosphere, or corona, regularly reaches temperatures of several million degrees Celsius. So why is there such a disparity?

"That's a bit of a puzzle,” said lead researcher Jeff Brosius, a space scientist at NASA's Goddard Space Flight Center, in a press release. "Things usually get cooler farther away from a hot source. When you're roasting a marshmallow you move it closer to the fire to cook it, not farther away.”

One theory, proposed by astrophysicst Thomas Gold in 1964, was that thousands of tiny ‘nanoflares’ are constantly peppering the corona with millions of degrees of heat every second to keep it much warmer than the photosphere below. They do this by releasing energy, which heats the plasma nearby to temperatures of around 10 million degrees Celsius. But because nanoflares are believed to cool down so quickly - leaving little evidence for their super-heated activities - and because they're impossible to observe individually, this theory has been very difficult to prove. Until now.

Thanks to a little research rocket that NASA launched towards the Sun in April 2013, Brosius and his team have been able to identify the heating activities of nanoflares in the corona in unprecedented detail.

To do so, they looked at six minutes of data from the rocket, which is designed to record a snapshot of the solar atmosphere once every 1.3 seconds. Part of NASA's EUNIS mission (short for Extreme Ultraviolet Normal Incidence Spectrograph), the rocket is equipped with a super-sensitive spectrograph, which gathers information about what material is present at any given temperature based on the light it emits. The rocket scanned one of the ‘active regions’ of the Sun - which are special, highly magnetic regions where sunspots, solar flares and coronal mass ejections are common occurrences - for light emissions.

As light from this active region streamed into the EUNIS spectrograph, the instrument separated it into various wavelengths. The wavelengths were plotted out on what's known as an emission line, which allowed the researchers to identify the atoms present in the region. From this, they identified the presence of material with a temperature of 10 million degrees Celsius. This, they report, is the strongest evidence we have that tiny nanoflares are heating the plasma up 10 million degrees to keep the corona hotter than the Sun's surface.

"The fact that we were able to resolve this emission line so clearly from its neighbours is what makes spectroscopists like me stay awake at night with excitement," said Brosius in the press release. "This weak line observed over such a large fraction of an active region really gives us the strongest evidence yet for the presence of nanoflares."

The team has published the results in the Astrophysical Journal, and you can watch a video about the discovery below:

https://www.youtube.com/watch?v=Hg5tla7s-ys

An Indian startup has developed smart shoes to help the visually impaired

Lechal is new kind of shoe technology that helps people find their way without having to look at their smartphone. 

Image: YouTube capture/Lechal

Ducere Tech, an Indian startup that designs wearable technology, has developed interactive, vibrating footwear that helps users find directions. The new shoe technology is called Lechal, which means “take me there” in Hindi. 

First, the users must enter their destination in the Lechal app using Google Maps or another navigation app. Their smartphone then connects via Bluetooth with a small module located in the back of each shoe, near the heel. The right or left module will vibrate every time the users have to take a turn, pointing them in the right direction. 

Its creators, Krispian Lawrence and Anirudh Sharm, developed the device aiming to improve the aids currently available to the visually impaired. They told the Indian magazine White Print, which is printed in Braille, that Lechal is their attempt at developing a technology that can help visually impared people navigate unfamilar areas by providing vibrating cues that can tell them where take a turn. The new technology is designed to complement the white cane—the walking stick that blind people and those with severe vision loss use to travel independently. 

Lawrence and Sharm—who hope their creation provides “people who are visually challenged the confidence to independently move around in familiar and unfamiliar areas”—have partnered with doctors from the LV Prasad Eye Institute in India to run clinical trials.  

Katie Nelson from Mashable reports that Lechal will also be sold as a lifestyle product that can track the number of steps taken and calories burned. The shoes will cost about US$150, but the price could be lower for those who only want to buy the insole platforms, which can be adapted to any type of footwear. Nelson reports that the first orders will be shipped in March 2015.

Watch the video below to see how Lechal works as a lifestyle product:

https://www.youtube.com/watch?v=ucK6jhdRlUY

Scientists discover a genetic indicator that could help prevent suicides

Researchers have found that mutations in a gene that helps to cope with stress could increase the risk of suicide. Now they will try to develop a blood test to predict the risk. 

Every 40 seconds someone in the world commits suicide. But a new discovery in the US by Johns Hopkins University researchers could help lower this statistic.

The researchers analysed 150 brain samples of deceased mentally ill and healthy people, including some of patients who had committed suicide. They discovered that all of those who had taken their lives had a mutation in the SKA2 gene.

This gene is expressed in the prefrontal cortex of the brain, and it determines how the brain reacts to stress hormones such as cortisol.

“If the gene’s function is impaired by a chemical change,” explains Caelainn Hogan from theWashington Post, “someone who is stressed won’t be able to shut down the effect of the stress hormone, which would be like having a faulty brake pad in a car for the fear centre of the brain, worsening the impact of even everyday stress.”

To confirm their results, the scientists analysed blood samples of 325 participants in the Johns Hopkins Center for Prevention Research Study, and found that those who had suicidal thoughts or had tried to commit suicide presented chemical alterations in the SKA2 gene.

And their blood test predicted with 80 to 90 percent accuracy whether a person had suicidal thoughts or had made an attempt to take their own life.

"We have found a gene that we think could be really important for consistently identifying a range of behaviours from suicidal thoughts to attempts to completions," psychiatrist and behavioural scientist Zachary Kaminsky, lead author of the study, said in a news release. "We need to study this in a larger sample but we believe that we might be able to monitor the blood to identify those at risk of suicide."

This study, which was published in the American Journal of Psychiatry, will help in the development of a blood tests that could predict if a person has mutations in the SKA2 gene and is prone to excess levels of stress and anxiety, which may lead to suicidal thoughts or attempts.

Scientists use light to stitch ‘invisible’ nanoparticles together

A team working on invisibility cloak technology has come up with a new technique that uses light to thread long chains of nanoparticles into light-refracting material.

At the centre of this new technique are tiny blocks made from ‘metamaterials’ - a special type of artificial material engineered to have properties unlike anything found in nature. These nanoparticle building blocks are just a few billionths of a metre wide, and researchers from the University of Cambridge in the UK have figured out how to control the way light flows through them. 

Controlling the way light interacts with a material is a key element of any ‘invisibility’ technology, and these metamaterials have been designed to refract light in a direction that renders them invisible to the naked eye.

In order to do this, the researchers needed to 'stitch' the metamaterial nanoparticles together into several long strings, which they did by placing the metamaterials in some water and blasting them with an unfocused laser light. "These strings can then be stacked into layers one on top of the other, similar to LEGO bricks," they say in a press release. "The method makes it possible to produce materials in much higher quantities than can be made through current techniques.”

Now, what we really want to know is… when do we get our invisibility cloaks? The next step is figuring out how to build bridges between the nanoparticles so they can be produced in larger quantities. "There is a knack to doing this," says Katie Collins at Wired UK, "and it involves spacing the material blocks carefully and accurately using barrel-shaped molecules calledcucurbiturils so that it's as easy as possible to retain control over the process."

Unexpected stem cell factories found inside teeth

Nerve cells sometimes spontaneously transform into stem cells inside teeth, researchers have discovered.

Development is typically thought to be a one-way street. Stem cells produce cells that mature into specific types, such as the neurons and glia that compose nervous systems, but the reverse isn’t supposed to happen. Yet researchers have now discovered nervous system cells transforming back into stem cells in a very surprising place: inside teeth. This unexpected source of stem cells potentially offers scientists a new starting point from which to grow human tissues for therapeutic or research purposes without using embryos.

“More than just applications within dentistry, this finding can have very broad implications,” says developmental biologist Igor Adameyko of the Karolinska Institute in Stockholm, who led the new work. “These stem cells could be used for regenerating cartilage and bone as well.”

Researchers knew that the soft “tooth pulp” in the center of teeth contained a small population of mesenchymal stem cells, the type of stem cell that can mature into teeth, bones, and cartilage. But no one had conclusively determined where these stem cells came from. Adameyko figured that if he could trace their development, he might be able to recreate the process in the lab, thereby offering a new way of growing stem cells for tissue regeneration.

He and his and colleagues were already studying glial cells, which support and surround neurons that wind through the mouth and gums and help transmit signals of pain from the teeth to the brain. When they added fluorescent labels to a set of glial cells in mice, they saw that over time, some of them migrated away from neurons in the gums toward the inside of teeth, where they transformed into mesenchymal stem cells. Eventually, the same cells matured into tooth cells, the team reported this week in Nature.

Before this experiment, it was generally believed that nervous system cells could not revert back to a flexible stem cell state, so it was a surprise to see that process in action, Adameyko says. “Many people in the community were convinced … that one cell type couldn’t switch to the other,” he says. “But what we found is that the glial cells still very much maintain the capacity” to become stem cells. If researchers can learn which chemical cues in the teeth pulp signal glial cells to transform into mesenchymal stem cells, they could have a new way to grow stem cells in the lab, he adds.

“This is really exciting because it contradicts what the field had thought in terms of the origin of mesenchymal stem cells,” says developmental biologist Ophir Klein of the University of California, San Francisco, who was not involved in the new work. But it’s also just the first step in understanding the interplay between the different cell populations in the body, he adds. “Before we really put the nail in the coffin in terms of where mesenchymal stem cells are from, it’s important to confirm these findings with other techniques.” If that confirmation comes, though, a new source of stem cells for researchers will be invaluable, he says.

Watch: This is why tattoos are permanent

Thank your immune system for those pretty stars on your neck that you love to show off.

If we shed about 40,000 skin cells per hour, how is it that tattoos don’t disappear after a few months? Why do they last ‘forever’?

The answer is not as straightforward as we would like it to be, but this TED-Ed video by educator Claudia Aguirre, director Hector Herrera and producer Pazit Cahlon, explains what happens in your body when the dye invades it.

When you get a tattoo, tiny needles loaded with ink will puncture your skin and penetrate both the epidermis—the outermost layer of skin—and the dermis—the inner skin layer, which contains blood vessels, hair follicles, glands, nerves and lymph vessels.

The wounds made by the needles cause inflammation, and the immune system quickly reacts by sending a type of white blood cells known as macrophages to heal the affected area. This process is what makes tattoos permanent.

Macrophages are ‘hungry’ cells that gobble on foreign material—in this case dye particles—to speed up the wound-healing process. Some of the macrophages that have 'eaten' the particles will go back to the lymph nodes, but others will stay in the dermis.

The rest of the dye will be soaked up by skin cells known as fibroblasts, and those, along with the macrophages, make your tattoo permanent.

And if you thought that the Chinese character you got tattooed in your most recent trip meant ‘peace’ and someone just recently pointed out that it actually means ‘kung pao chicken’, worry not—tattoos can be removed. Watch the video below to discover how it’s done.

https://www.youtube.com/watch?v=DMuBif1mJz0