For your brain, romantic rejection is the same thing as being physically burned

When your sweetheart dumps you, there's a reason why it hurts so much. It turns out your brain registers the psychological hell in exactly the same way it registers physical pain.

A group of scientists used fMRI scans to study the brains of people dealing with being rejected, and compared them to the brains of people experiencing physical pain. They found that the exact same regions of the brain are involved in processing both experiences. For humans, social rejection is tantamount to literal injury.

Write the authors in a paper published this week in the Proceedings of the National Academy of Sciences:

We tested this hypothesis by recruiting 40 individuals who felt intensely rejected as a result of recently experiencing an unwanted romantic relationship break-up (see Methods). Participants performed two counterbalanced tasks during functional MRI (fMRI) scanning: a Social Rejection task and a Physical Pain task (for design, see Fig. 1). Briefly, the Social Rejection task compared Ex-partner trials, in which participants viewed a headshot of their former partner and thought about their specific rejection experience, and Friend trials, in which participants viewed a headshot of a friend who was the same sex as their ex-partner and thought about a recent positive experience they shared with that person. The Physical Pain task also consisted of two types of trials: Hot trials, in which participants experienced noxious thermal stimulation on their left forearm, and Warm trials, in which participants experienced nonnoxious thermal stimulation in the same area. Participants rated how they felt after each task trial using a five-point scale, with lower numbers reflecting more distress.

And indeed, they saw the same regions of the brain lighting up during both physical and mental tasks - specifically, "areas that support the sensory components of physical pain (secondary somatosensory cortex; dorsal posterior insula)." The researchers say that their work could shed light on why different kinds of social rejection can lead to physical pain and other ailments. Ultimately, they say, our brains reveal an intensely strong connection between emotions and physical sensations. An interesting area for future research would be whether witnessing somebody else's distress also affects our brains the same way physical pain does - in other words, do we literally feel the pain of others?

Read the full scientific paper via PNAS

Source: io9

A wavelength of light that could fix heart problems and deafness

We can hear the light and feel it in our hearts. It's not just terrible poetry - it might be fact. Scientists have shown that infrared light can stimulate the muscles in your heart and inner ear.

Researchers at the University of Utah have been spending long hours shooting infrared lasers at mouse heart cells and toadfish inner-ear cells. They did this not just for fun (though it has to be fun) but for science. The heart cells were muscles cells called cardiomyocytes, which are also found in humans. The inner ear cells were the tiny hairs that line the inner ear, and oyster toadfish inner ear cells have been used for quite some time as a model for human ear and balance responses. When the scientists saw that the cells responded to the laser, several new medical possibilities opened up.

One common misconception about infrared is it's the same as heat. Often hot bodies, such as heaters, put off both regular heat and infrared radiation, but heat is the random motion of atoms within a substance. The faster the atoms are moving, the hotter the substance is. Infrared radiation is an electromagnetic wave just like regular light - it's just too low-energy to be picked up by human eyes. Infrared light can cause objects to heat the same way regular light causes them to heat - light is energy and when substances absorb energy they heat up. But it's not heat, it's light.

And so it's very strange that something in our ears and hearts might be light-sensitive. The small hair cells of the inner ear are usually stimulated by mechanical changes. Vibrating air causes them to vibrate. Gravity can tug them one way or the other, which is where the human sense of balance comes from - if people tip their heads sideways they feel it in their ears. It's not like the inner ear gets a lot of optical stimulation. (And if all goes well, the heart doesn't see light very often either.) Why would they respond to infrared?

The hair cells of the inner ear, and the cardiomyocites are full of mitochondria. These are the little organs that act as cellular power stations, producing the molecule that serves as chemical energy for the cell. During the course of their operations, they let calcium ions flow in and out of them. Infrared light affects that flow. Calcium ions trigger the nerve cells to release neurotransmitters and the muscles cells to contract.

The ability of these cells to sense infrared radiation has a lot of medical professionals excited. Optical, instead of electrical, pacemakers are a possibility, although a remote one since current pacemakers work very well. Cochlear implants, devices that convert sound to electrical signals to help deaf people hear, could be much improved by the use of infrared signals. Balance disorders, or the natural loss of balance due to aging, could also be ameliorated with pulses of infrared in the ear. Plus, these infrared devices wouldn't be as invasive as current ones. Infrared can penetrate into the body a certain distance, which would eliminate the need to give the devices direct contact with nerve cells.

They could be a boon to people losing their sight as well. Certain diseases cause people to lose the rods and cones in their eyes that receive optical signals but not the underlying nerve cells. Obviously, these people can't send electrical impulse directly into their eyeballs, but they can use infrared signals to trigger the nerve cells. It looks like this discovery can restore any number of senses to people currently going without.

Source: io9 Via The Journal of Physiology times Two.

Image by Sebastian Kaulitzki/Shutterstock

Man-made 'CLOUDS' to shade 2022 World Cup in Qatar

With the World Cup always held in the European off-season in June and July, the awarding of the 2022 World Cup to Qatar offers the prospect of players and spectators sweating through the hottest part of the year. Doha sees an average top temperature of 41 degrees Celsius (106°F) in these months with the possibility of top temperatures as high as 50°C (122°F). While shifting the World Cup to the cooler month of January has been mooted and since rejected, a team of engineering scientists from Qatar University (QU) have taken a more high-tech approach to solving the problem – they've reportedly developed a type of artificial "cloud" designed to float above the World Cup venues and provide fans and players with relief from the blazing sun.

The proposed stadiums for the World Cup unveiled a year ago – which included theLusail Iconic Stadium – would all employ cooling technology capable of reducing temperatures inside by up to 20°C (36°F), but concerns remain about training grounds.

The artificial clouds system was invented by a team led by Dr Saul Abdul Ghani, Head of the Mechanical and Industrial Engineering Department at QU, who toldGulf News that the "clouds" would be made from a lightweight carbon structure carrying a giant envelope of material containing helium gas. The "cloud" would also feature solar panels on its upper surface to power engines that allow the cloud to be moved via remote control.

The system would initially cost around US$500,000, with prices coming down with commercial scale production. It's unclear whether the clouds will actually be built. With still eleven years till the kick off of the 2022 World Cup, the long term forecast is mainly sunny with a chance of cloud.

Source: Gizmag Via The Daily Mail.

World's First 'Artificial Leaf' Created By MIT Labs

A practical artificial leaf that can turn sunlight and water into energy as efficiently as the real thing has long been a Holy Grail of chemistry, and researchers at MIT may have finally done it. Today at the National Meeting of the American Chemical Society researchers from MIT’s Nocera Lab, led by Dr. Daniel Nocera, claimed that they’ve created an artificial leaf made from stable and--more importantly--inexpensive materials.

The artificial leaf looks nothing like the natural leaf that it mimics, but its inputs and outputs are the same. Made of silicon, electronics, and various catalysts that spur chemical reactions within the device, the artificial leaf uses sunlight to break water into hydrogen and oxygen which can then be used to create electricity in a separate fuel cell. Placed in a gallon of water and left in the sun, these artificial leaves could provide a home in the developing world with basic electricity for a day, Nocera said.

The Nocera Lab’s artificial leaf, it should be noted, isn’t the first working attempt at recreating photosynthesis in artificial materials. But previous attempts have led to artificial leaves full of unstable materials that are expensive and lead to short life spans. Nocera and his team identified a set of inexpensive, common catalysts including nickel and cobalt that get the job done with far less expense. And in the lab their playing-card-sized leaves have worked continuously for 45 straight hours without a drop in output.

Nocera and company will next try to boost both efficiency and lifespan of their photosynthetic material. It’s still a workbench technology at this point, but the leap forward presented here is significant. Scaled and mass produced, something like the Nocera Lab’s leaf could be the key component to shifting toward a hydrogen-based economy. In the nearer term, such technology could at the very least power parts of the globe that are currently off the grid with clean, plentiful, and easy-to-come-by energy.

Source: Popsci via Eurekalert

SmartBird flying robotic seagull created by Festo.

Festo has added to its robotic menagerie with the creation of a robotic seagull that weighs just 450 g (15.87 oz) and boasts a wingspan of 1.96 m (6.4 ft). Dubbed the SmartBird, the ultralight flying robot was inspired by the herring gull and can take off, fly and land autonomously, without the help of any additional drive systems.

In creating the SmartBird, Festo says it has succeeded in deciphering the flight of birds. The robot's wings not only beat up and down, with a lever mechanism increasing the degree of deflection to increase from the torso to the wing tip, but also twist at specific angles along their length in the same way that a real bird's do so that the leading edge is directed upwards during the upward stroke.

Directional control is achieved through the opposing movement of the robot's head and torso sections, which is synchronized by means of two electric motors and cables. This enables it to bend aerodynamically, with simultaneous weight displacement, and is responsible for the SmartBird's agility and maneuverability.

As with a real bird, the SmartBird's tail isn't just for show either. It produces lift and functions as both a pitch elevator and yaw rudder. In addition to stabilizing the robot in a similar way to an aircraft's conventional vertical stabilizer, the tail also tilts to initiate left and right turns and rotates about the longitudinal axis to produce yaw.

Packed inside the SmartBird's torso are the battery, engine and transmission, the crank transmission and control and regulation electronics. Wing position and torsion can be monitored via two-way ZigBee protocol radio communication and can be adjusted and optimized in real time during flight.

Festo says developing the SmartBird has provided insights that will help it in a variety of areas. The robot's minimal use of materials and lightweight construction will help increase efficiencies in resource and energy consumption, while the functional integration of its coupled drive units have provided ideas the company says it can transfer to the development of hybrid drive technology. Additionally, analysis of its flow characteristics during development has provided insights into ways to optimize future designs. Another plus is that it won't try and steal your chips at the beach.

Source: Gizmag Via IEEE Spectrum

Scientists use bacteria to create fuel from sunlight and CO2

Shewanella bacteria, which produces ketones that are processed into fuel

Researchers from the University of Minnesota have announced a breakthrough in the quest to create a viable fuel alternative using greenhouse gases. The process uses two types of bacteria to create hydrocarbons from sunlight and carbon dioxide. Those hydrocarbons can in turn be made into fuel, which the scientists are calling "renewable petroleum."

The process starts with Synechococcus, a photosynthetic bacterium that fixes carbon dioxide in sunlight, then converts that CO2 to sugars. Those sugars are then passed on to another bacterium, Shewanella, which consumes them and produces fatty acids. University of Minnesota biochemistry graduate student Janice Frias discovered how to use a protein to transform those acids into ketones, a type of organic compound. Her colleagues in the university's College of Science and Engineering have developed catalytic technology that allows them to convert those ketones into diesel fuel.

"CO2 is the major greenhouse gas mediating global climate change, so removing it from the atmosphere is good for the environment," said Frias' advisor, Prof. Larry Wackett. "It's also free. And we can use the same infrastructure to process and transport this new hydrocarbon fuel that we use for fossil fuels."

The university is in the process of filing patents on the process.

The research is being published in the upcoming issue of the Journal of Biological Chemistry.

Source: Gizmag

Brain-Machine Interface a Possibility?

It’s reminiscent of Cartman’s runaway Trapper Keeper notebook in that long-ago episode of South Park, but researchers at the University of Wisconsin-Madison may be scratching the surface of a new kind of brain/machine interface by creating computer chips that are wired together with living nerve cells.

A team there has found that mouse nerve cells will connect with each other across a network of tiny tubes threaded through a semiconductor material. It’s not exactly clear at this point how the nerve cells are functioning, but what is clear is that the cells seem to have an affinity for the tiny tubes, and that alone has some interesting implications.

To create the nerve-chip hybrid, the researchers created tubes of layered silicon and germanium that are large enough for the nerve cells’ tendrils to navigate but too small for the actual body of the cell to pass through. They then introduced nerve cells to the tubes and found that the cells will readily thread their tendrils through them--even through complex geometries like helical curves--to connect with each other physically.

What isn’t clear is whether or not the cells are actually communicating with each other they way they would naturally. Going forward, the team aims to get sensors into the chips to see exactly how they are interacting. But the fact that nerve cells will follow the tubes along a preset path designed by researchers belies thrilling prospects.

For instance, nerve-electronic hybrid chips would make great places to test neurological drugs or to study the way nerve cells afflicted with disorders like Parkinson’s communicate. But even more tantalizing is the idea of a nerve-computer interface that would enable the kind of Skywalker-esque control of artificial limbs that is the holy grail prosthetics research.

Source: Popsci via Discovery News

Gemlike 3D microscope lens developed For 3D Microscopy

Engineers from Ohio State University have developed what they say is the world's first microscope lens capable of obtaining three-dimensional images. While 3D microscopy has already been achieved, it has previously required the use of multiple lenses, or of a single camera that moves around the object being imaged. The new device, however, is just a single lens that sits in place on an existing microscope.

The prototype lens was cut from a transparent piece of polymethyl methacrylate thermoplastic, also known as acrylic glass, using a commercially available milling tool outfitted with a diamond blade. The finished product, which is about the size of a fingernail, looks not unlike a gemstone. One side has a central facet circled by eight other facets, while the other side is flat. Unlike a gemstone, however, the facets are not intended to be identical – each one differs very slightly from the others in size and angle, which is an example of what is known as "freeform optics."

The lens was attached to a camera-equipped microscope, which looked down through the faceted side, to objects placed underneath. The nine facets each captured their own images of the objects, from slightly different angles. Those nine images were then fed to a computer, which combined them into one three-dimensional image. Objects that were observed included the tip of a ballpoint pen, with a diameter of about 1 millimeter, and a micro drill bit, with a diameter of just 0.2 mm.

It is hoped that once commercialized, the lens could be used in the manufacturing of microelectronics and medical devices, for medical testing, and to replace more complex machine vision systems. Although the prototype was machine milled, the engineers state that subsequent lenses could be less expensively produced via traditional molding techniques.

Allen Yi, associate professor of integrated systems engineering at Ohio State, and postdoctoral researcher Lei Li led the research. Their findings were recently published in the Journal of the Optical Society of America A.

Source: Gizmag

Reversal Of Aging Process in Human Brain Possible ?

Bees can become mentally young again with just a few simple alterations to their otherwise fixed routines. Because the brains of bees are surprisingly like our own, this trick could help fight dementia and keep human minds young and flexible.

Norwegian researcher Gro Amdam had groups of older bees take part in learning and memory tests. The bees were challenged to associate a particular scent with a particular reward, and then be able to remember that association later on. Most of the older bees were able to make the connection, but more slowly than their younger counterparts, and those bees that had symptoms equivalent to human dementia were unable to make the connection at all, suggesting their short-term memory and ability to learn were both in sharp decline.

Here's where it gets interesting. Bee hives have a fairly strict social structure - the older bees leave the hive to collect food, while the younger bees remain inside and care for larvae. Amdam flipped this by creating a hive where the older bees were again in charge of larvae. This simple alteration caused an instant surge in the older bees' cognitive abilities, with half of the bees showing marked improvement in their learning and memory.

Even better, Amdam has been able to zero in on the physical alterations engendered by this social change. She discovered that eight different proteins associated with growth, repair, and maintenance of the brain cells had undergone massive with growth, with some reaching levels twice that of normal. Many of these proteins have direct human equivalents, which raises the distinct possibility that similar results could be produced in humans.

Amdam explains:

"This is evidence of a certain flexibility in the bee brain, and it is conceivable that the brains of other animals and humans could have a similar potential. If so, the question is whether we would be able to figure out how to tap into this flexibility. Another approach would be to try to figure out how the relevant bee proteins work, and then create substances that trigger similar effects."

Source: io9 Via the Research Council of Norway.

BLOOD: Improving Crime Scene Analysis Forensic Techniques

Lauren Burke/Getty Images

The aftermath of violent crimes is nothing like what we see on TV, says Stephen Morgan, a forensic analytic chemist. “Crime scenes are messy, chaotic. There’s a lot to look at.” Too much, in fact. What’s needed are methods to simplify the forensic process without damaging evidence at the scene. These three breakthroughs will do just that.

Where

Investigators use spray-on reagents to locate blood spatter that’s too small to see. But chemicals can contaminate evidence or give false positives. Stephen Morgan and Michael Myrick of the University of South Carolina have developed an infrared camera system that exposes microscopic traces of blood without using chemicals. The device targets blood proteins, which remain long after visible blood has been wiped away, filtering background infrared to reveal blood residue that can’t be seen with the naked eye.

How

Detectives use spatter reconstructions to piece together what a crime might have looked like as it happened. Typically, investigators pin string from blood stains to a possible point of origin, but this method overlooks the fact that blood drops arc through the air. Forensic-surveying engineer Ursula Buck and her team at the University of Bern in Switzerland use laser scanners and imaging software to re-create accurate spatter trajectories. First, digital photographs of the crime scene are stitched into a panorama that shows blood-stain size and location, while the laser scanner creates a 3-D rendering of the room. The mass of each droplet is then calculated based on the size of the stain. Finally, using an algorithm developed by the Swiss team, every drop of blood has its path re-created, no string attached.

Who

Forensic scientists had no reliable method for establishing age using blood samples before last November, when Manfred Kayser and his colleagues at Erasmus MC University Medical Center Rotterdam in the Netherlands announced that they had developed a process to determine age, plus or minus nine years. The test examines white blood cells called T cells by looking for the snippets of DNA that form inside newly made T cells as they fight infections. As we age, our bodies create fewer T cells (a reason the elderly are more susceptible to colds). The more of these DNA snippets, the younger the perp. “Police are desperate to get information,” Kayser says. “We’re mining human biology to give them a new tool.”

Source: Popsci

The secret to making long-term memories

One of humanity's most incredible abilities is being able to remember things that happened many years, perhaps even many decades ago. But it's only now that neuroscience is able to really explain how we can form such long-lasting memories.

Scientists have long suspected that the key to remembering things from long ago is what's known as long-term potentiation, or LTP. This basically involves a long-lasting increase in the signals sent along the connections between particular brain cells, which in turn allows us to keep recalling things we experienced decades after they first occurred. But what actually causes LTP had eluded scientists...until now.

Duke researchers have discovered a cascade of special molecules that make an otherwise very short-lived signal last for tens of minutes. That might not seem like a very long time, and yet that's the likely building block on which all our long-term memories rest. Over time, these minutes-long connections, or synapses, would be reinforced and strengthened into connections that can rest months, years, and even decades.

Lead researcher Ryohei Yasuda explains the team's findings:

"We found that a biochemical process that lasts a long time is what causes memory storage," said Yasuda, who is a Howard Hughes Medical Institute Early Career Scientist. The signaling molecules could help to rearrange the framework, and give more volume and strength to the synapses. We reasoned that a long-lasting memory could possibly come from changes in the building block assemblies."

Two of the crucial molecules in strengthening these connections - and, by extension, maintaining the long-term plasticity of the synapses and our continued ability to learn new things - are known as Rho and Cdc42. We already know that mental diseases including Alzheimer's disease are linked to abnormal signals from these molecules, and Yasuda is optimistic that this new research will help us understand more about the underpinnings of the conditions.

Source: io9 Via Nature. Image via.

Semiconductors threaded with nerve cells could be the first step towards biological computers

We assumed that in the future humans, or other biological entities, would receive mechanical or electronic 'upgrades'. It looks like it could be the other way around. Machines might be getting biological upgrades.

Adding computer chips to someone's brain is a long way away, but adding neurons to a computer may be just around the corner. Researchers have just added nerve cells to specially-constructed semi-conductors, and the results seem to indicate that one day, biological nerve cells will be strung through computers. We won't put the ghost in the machine - we'll put the meat in it.

This particular step in human/machine evolution was taken at the University of Wisconsin-Madison. Researchers constructed little tubes of silicon and germanium. These tubes are often used in computer technology, but they were chosen mostly for their ability to insulate the electric impulses that run down nerve cells. After the network of tubs had been constructed, mouse nerve cells were added to the structure. The tubes were specially sized so that the main bodies of the cells were too big to fit inside them, but the long axons - the slender 'arms' of the cells - were perfectly able to fit down the tubes. After a little while, the nerve cells has threaded themselves into the network of tubes.

This represents a very promising direction in mechanical-biological integration, but it also signals that the integration might not go the way we've been expecting. Machines are still struggling with things like walking, recognizing pictures, and the basic manipulation of objects. Humans have no such difficulty. In the future, instead of putting robot hands on a human, they'll put human hands on a robot - and have them controlled by human neurons going to a basic human brain.

Source: PopSci Via Science News.

Implantable Tumor Tracker a Tiny Lab That Lives Inside the Body And Reports Back

The Implantable Tumor-Tracker

Rather than bringing people into the lab, researchers at MIT are putting tiny labs into people via a tiny implantable capsule that can track the growth of a tumor or detect heart-deterioration or even silent heart attacks from inside the body.

The miniature lab is small enough to implant via a needle during a normal biopsy, and can remain inside the body vigilantly watching for increased tumor growth. The inside of the device is filled with nanoparticles, each sporting an antibody specially designed to bind to specific molecules like those that are produced by certain kinds of tumors or by damaged heart muscle cells.

A semi-permeable membrane keeps the nanoparticles in while allowing molecules from the body to pass through. Doctors can then check for clusters of particles with a simple MRI. Judging from the density of clusters of certain molecules, doctors can tell if a nearby tumor is growing, receding, or remaining static. Or, in the case of patients with heart issues, doctors can monitor for silent heart attacks--small attacks that often go unnoticed--or for the presence of damaged heart tissues in those at risk of a second heart attack.

To simplify the whole affair, the MIT team is now developing a prototype of the device that can produce a signal when prompted by a magnetic wand that doctors can simply wave over the embedded sensor. Such a scheme cuts down on complexity, and reduces the need for expensive MRI scans.

Source: Popsci via New Scientist

How Does Nuclear Radiation Do Its Damage?

Officials in protective gear check for signs of radiation

Ionizing radiation—the kind that minerals, atom bombs and nuclear reactors emit—does one main thing to the human body: it weakens and breaks up DNA, either damaging cells enough to kill them or causing them to mutate in ways that may eventually lead to cancer.

After last week’s earthquake and tsunami in Japan, four nuclear reactors at the Fukushima Daiichi plant are now damaged and releasing radiation. Workers trying to keep the reactors from getting worse are themselves being exposed, while the Japanese government has called for anyone within 20 kilometers of the plant to evacuate.

Nuclear radiation, unlike the radiation from a light bulb or a microwave, is energetic enough to ionize atoms by knocking off their electrons. This ionizing radiation can damage DNA molecules directly, by breaking the bonds between atoms, or it can ionize water molecules and form free radicals, which are highly reactive and also disrupt the bonds of surrounding molecules, including DNA.

Peter Dedon, a member of the Radiation Protection Committee at MIT, explains: “What happens is that the nucleus of radioactive elements undergoes decay and emits high-energy particles. If you stand in the way of those particles, they are going to interact with the cells of your body. You literally get a particle, an energy packet, moving through your cells and tissues.”

If radiation changes DNA molecules enough, cells can’t replicate and begin to die, which causes the immediate effects of radiation sickness -- nausea, swelling, hair loss. Cells that are damaged less severely may survive and replicate, but the structural changes in their DNA can disrupt normal cell processes -- like the mechanisms that control how and when cells divide. Cells that can’t control their division grow out of control, becoming cancerous.

With ingested particles, some may pass through the body before they do much damage, but others linger, Dedon says. Radioactive iodine-131 poses a particularly significant risk, because it is absorbed rapidly by the thyroid gland and held there. That is why it is recommended that those who may be exposed to radioactivity in the air pre-dose themselves with iodine pills: the non-radioactive iodine is absorbed by the thyroid, which then does not absorb radioactive iodine if it comes along.
Radiation exposure risk is measured in units called sieverts, which take into account the type and amount of radiation, and which parts of the body are exposed, allowing us to compare different kinds of exposures in one scale.

In a typical year, a person might receive a total dose of two or three millisieverts from things like ambient radioactivity, plane flights and medical procedures. In the U.S. the annual exposure limit for nuclear plant workers is 0.05 sieverts per year. At or below these levels, the enzymes that repair DNA keep up with damage enough to keep the risk of cancer low. Above them, the body’s systems of repair can’t keep pace. 100 millisieverts a year is the threshold above which cancer risk starts to increase, according to the World Nuclear Association.

According to reports, radiation levels have fluctuated at Fukushima, rising at one reading to 400 millisieverts per hour. At that level, Dedon says, seven minutes would bring you to the U.S. yearly limit. Over an hour could be a lethal dose. The 400 millisieverts level was not a sustained measurement and levels continue to fluctuate much lower.

Dedon stresses that because radiation dissipates, like light, by the square of its distance, even if levels are high in the plant, just a few miles away, they would be miniscule. The greater danger for people living in the area is the release of radioactive particles into the air, which can accumulate in the body, damaging tissue over time and causing cancer.

Receiving a one-sievert dose of radiation in a day is enough to make you feel ill, according to Dedon. “At one to three, you have damaged bone marrow and organs, and you’ll really be sick. At three to six you add hemorrhaging, and more infection,” he says. “From six to ten, at that level death is something like 90 percent. And above ten, they just call that incapacitation and death.”
Source: Popsci

How does radiation travel, and what kinds of damage can it do?

The nuclear disaster in Japan has left many people in danger of exposure to radiation and radioactivity. Some are simply fearful. What exactly is this radiation? And what threat does it pose? We've got some answers below.

What is radiation?

Radiation has become a frightening word, but there's not necessarily anything dangerous about it. Visible light is radiation. Heat is radiation. Many news channels say that explosions or meltdowns 'leak' radiation into the atmosphere, but few say what exactly this 'radiation' is.

At least one of the explosions at the nuclear power plants has vented steam that contains radioactive materials. The nuclear power plant produces energy via fission of uranium-235, which means it splits uranium-235 into smaller atoms. Two types of these smaller atoms, cesium-137 and iodine-121, were found about sixty miles from the Fukushima Daiichi power plant. These radioactive materials can't be detected biologically, and so can be rubbed on the skin, eaten, or breathed in. These atoms break down into even smaller atoms, and their neutrons can change to protons. When this happens, they give off highly energetic gamma rays.

They also give out beta radiation. Beta particles are basically ejected electrons. Although they are not as energetic as gamma rays, they can cause problems if left on the skin for a prolonged time. Since radioactive materials can be ingested, beta particles can also be ejected inside the human body, where they can do a lot of damage.

What does radiation do?

Gamma rays are the highest energy rays in the electromagnetic spectrum. They are so energetic that they can travel great distances through the air or other material, and can pass through living material, which means any tissue in your body can be exposed to them. Gamma radiation is called ionizing radiation. When it encounters an atom, it can rip the electron right off, leaving an ion behind.

Once an atom becomes an ion, it reacts to the world around it in a different way. It can be attracted to certain things, repelled by others, or even join together with another atom. Since your living tissue is set up to work with non-ionic forms of atoms, introducing an ion into a part of the body where it doesn't belong has drastic consequences. Sometimes it only damages cells, but often it kills them off entirely. The effect depends on the level of ionization that the cells experience.

Low level ionization just causes some cells to be slightly damaged. This kind of damage is much the same as a sunburn. A sunburn is caused by relatively mild UV radiation, and only affects exposed areas of skin. Gamma radiation can burn any area of the body, and burns resulting from it are usually much more severe than sunburns. Although low level radiation exposure may not have any immediate effects, the damage can be done to the DNA inside your cells. This damage can cause your DNA to mutate, or behave abnormally. Ionization can also cause trouble when exposed cells divide - they may keep dividing without limit, causing cancer.

Higher levels of radiation have more immediate effects. Often the cells lining the intestines are damaged, and the body can't absorb water or nutrients. Bone marrow can also be affected. Without these, the body has a hard time fighting off external infections or diseases, and many victims of radiation die of infection. If, however, medical professionals are able to keep them alive and ward off infection, their bodies can recover.

Even higher levels of radiation exposure do damage to the vascular system. This damage is extensive, and can cut off the flow of blood to vital organs like the brain. When the damage is this severe, there is nothing that medicine can do to help the person affected. This level of radiation is almost always fatal.

Beta radiation is also very dangerous. The isotope iodine-131 is a particular worry because of its beta radiation and its placement within the body. Iodine-131 tends to bind to the thyroid. When it decays, the ejection of beta particles tends to harm fast-dividing cells. Since children are still growing, their cells are dividing particularly fast, and are very vulnerable. Too much exposure can cause thyroid cancer.

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How does radiation travel?

Gamma rays travel like any other electromagnetic waves - cutting a fairly straight line through world. They can move through a vacuum, or through air or water. They can also cut through light elements like aluminum or most metals. Lead can cut down on gamma radiation, but it can't really stop it. One inch of lead will cut any amount of gamma radiation by half. Another inch will cut it by another half, and so on, and so on. Practically speaking, a few feet of lead will weed out pretty much any gamma radiation, but technically nothing can block all gamma rays from coming through.

Radioactive materials are also tough to contain. Although they can be measured, and scrubbed off, they are made of tiny, invisible atoms. Once they are released into the air, they can get blown by the wind or rain down on the land, get absorbed or eaten by plants and animals, adhere to matter, and scatter out through the world.

How much radiation is dangerous?

Radiation is difficult to measure. Exactly how much radiation anyone has been exposed to depends on the material they were exposed to, the distance they were from that material, and the time period they were exposed for. Absorbed doses of radiation are measured in a unit called a gray, which is a ratio of the amount of material absorbed to the mass of the matter that absorbed it. One gray is one joule of energy released into one kilogram of absorbing matter.

Many nuclear agencies prefer to measure the amount of radiation absorbed in sieverts. A sievert takes into account the type of energy released, as well as the way it was transmitted, and how vulnerable the absorbing tissue is to radiation. The typical exposure to radiation is measured in millisieverts, or thousandths of a sievert. Generally, people are exposed to about 3 millisieverts of radiation per year. An X-ray gives people 4 millisieverts, a CT scan gives 10. A dose of five hundred millisieverts ushers in radiation sickness, while exposure to one sievert gives the victim a ten percent chance of death within 30 days.

When the Fukushima plant was at its worst, it was giving out radiation at a rate of about 400 millisieverts per hour. That meant that most workers needed to be evacuated immediately. Fortunately, the level went down to about .6 millisieverts an hour. Levels of radiation throughout the area continue to be monitored.

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Is there any way to avoid or treat radiation exposure?

The best way to avoid radiation exposure is to take steps to avoid materials contaminated with radioactive atoms. Distance is best - about 70,000 people have been evacuated from around the Fukushima plant. Clean food and clean water are also key. Families in the area of the plants are being encouraged to stay inside, to jam blankets and clothes in doors, and eat canned food.

The best defense people currently have only works against iodine-131. Since the thyroid absorbs iodine, and since it can be saturated with the stuff, children around the affected area are being given tablets containing normal iodine. When they eat them, the thyroid becomes filled with regular iodine, and can't take any more in, blocking the radioactive iodine from lodging in the body. Since iodine-131 has a half-life of eight days, the danger is temporary and can be staved off. Beyond that, there isn't much to be done about radiation exposure except treating the symptoms and getting screened for cancer regularly.

Although the danger is still great, most residents of Japan are being asked to stay calm. As are people elsewhere. The high level of radiation being given off by the Fukushima plant was a one time emission, and is unlikely to greatly affect residents of Tokyo, let alone residents of other countries. Radiation is to be avoided as much as possible, but it's also part of daily life.

Source io9 Via Scientific American, NY Times, EPA, GM, CDC, Sievert Systems, and The Independent.