In this weeks science roundup I decided on three very different stories from research which had been published this week including potential cures for paralysis, self destructing electronic and the science of zebra stripes.
POSSIBLE CURES FOR PARALYSIS
There were two different stories on helping to cure muscle paralysis this week, both involving a new way to help nerve cells to carry their signal. Muscle movement is normally controlled by motor neurons which are special nerve cells in the brain and spinal cord which relay signals from the brain to the muscles in the body to control motor functions. These include functions including walking, standing and importantly – breathing.
If the motor neurons are damaged due to spinal cord injuries or motor neuron disease there can be permanent loss of muscle function which results in paralysis.
The first study came from a paper published in Science on April 4th 2014 titled “Optical Control of Muscle Function by Transplantation of Stem Cell–Derived Motor Neurons in Mice“. In this paper, scientists were able to show a new way to artificially control muscles using light instead of electrical stimulation.
Their technique involved transplanting stem cells which were equipped with a molecular light sensor. These stem cells were programmed to turn into motor neurons when grafted onto the sciatic nerve of the animal, which in this case they were mice.
When blue light was shone onto these new cells, it would cause them to fire a signal down to the muscle. The study carried this out on mice that had paralysed leg muscles, and were able to make the leg to move by controlling it with light pulses.
Although this is very early research in a field known as optogenetics and the study is still far away from curing paralysis by implanting stem cells and lasers into patients, it does provide a new way to stimulate motor neurons without the pain of electrical current stimulation.
A video summarising the study can be seen here:
In the second study published just yesterday April 8th 2014 in the journal Brain, a paper titled “Altering spinal cord excitability enables voluntary movements after chronic complete paralysis in humans” explains how a small device which delivers a low pulse of electricity can be implanted under the skin of the abdomen can connect to electrodes placed near the spinal cord.
The researchers implanted four men who had been paralysed after spinal cord injuries and all four were able to move their legs again controlled by the electrical stimulator. How the implanted device is able to stimulate the spinal cord at the demand of the patient is sill unclear, as the electrodes are not in contact with their brain, however as you can see from the following video, one of the patients is very happy with its results:
CONTROLLED DISSOLVING OF ELECTRONICS
Imagine if all the electronics including the resistors and capacitors inside your phone dissolved so that there was no trace of it. This is the potential of the work presented in the paper “Study of Physically Transient Insulating Materials as a Potential Platform for Transient Electronics and Bioelectronics” released on April 1st 2014 in the journal Advanced Functional Materials.
This new type of material for electronics are known as transient materials and are made from special polymers and magnesium which completely dissolve in water. Although the concept of dissolving circuits has been around for a few years as shown in this 2012 video:
The ability to control how quickly the material dissolves is the new piece in the story. The researchers used a combination of PVA (poly vinyl alcohol) with gelatin or sucrose to create a coating matrix for electronics that enabled precise control over how quickly it dissolved depending on what the final application for the device would be.
In a new video released by the researchers a proof of concept was shown in which a LED light dissolved with just a few drops of water:
These controlled dissolve electronics have applications in the medical field where a doctor could implant a sensor to monitor the body and then get it to dissolve after the tests are complete. There is also the potential for it to be used as a security device in which electronics could be instantly destroyed so they can’t get into the wrong hands, for military personnel or even as a remote deactivation device for stolen credit cards.
WHY DO ZEBRAS HAVE STRIPES?
Finally, one of those questions that I thought I knew the answer to but now realise that I had it all wrong.
So why do Zebras have stripes?
There are several theories out there including camouflage, predator avoidance, heat management or social interaction.
I had always believed that the black and white striping system was to confuse predators as to the speed and direction that a zebra was running, to help the zebra to get away. My second guess would be that it was a bar code like system helping one zebra to identify another one. However it seems that scientific analysis shows there is no consistent support for the theories listed above and instead the evidence points towards the stripes acting to keep the flies away.
In a Nature Communications article published on April 1st titled “The function of zebra stripes” researchers attempted to account for the differences in patterning by studying different species and subspecies of zebras and horses. What they consistently found was that there was more striping on zebras who lived in parts of the world where there were more biting flies. Where there are tsetse flies, for instance, equids tend to come in stripes and where there aren’t – they don’t.
The scientists think that the vision of the fly is confused by the striped pattern resulting in the fly being unable to land on the black and white striped surface, although this was not scientifically confirmed.
The question I have is could this lead to a new type of stripy spray on insect repellent or a zebra bran of onsies?