Update: November 14, 2007

THE DARK AND THE LIGHT

By Pam Eastlick for THE DEEP on line

Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.

I thought I’d start this week with some medical news.  We all know about diabetes since it’s so common here on Guam.  If you have diabetes, you can no longer metabolize glucose normally.  Your blood fills up with sugar and there’s no room for the other components of blood necessary for your survival like white blood cells and platelets.

Your body stops producing a chemical called insulin and diabetics must take insulin every day for the rest of their lives.  There are two types of diabetes; one affects children and teens and the other, which seems to be a disease of ‘wearing’ affects people later in life.  Now researchers at Northwestern University seem to have discovered a third type of diabetes, and this one doesn’t cause the normal symptoms seen in the uncontrolled diabetic.  It causes Alzheimer's.

Your brain is the largest consumer of energy in your body, so it’s not surprising that insulin and insulin receptors are vital to learning and memory.  When insulin binds to a receptor at a synapse, it turns on a mechanism necessary for nerve cells to survive and memories to form.  Scientists have known for a long time that insulin resistance in the brain may cause Alzheimer’s disease.

Now scientists at Northwestern University have discovered why brain insulin signaling -- crucial for memory formation -- stops working in Alzheimer's disease. They’ve discovered a toxic protein found in the brains of individuals with Alzheimer's removes insulin receptors from nerve cells, rendering those neurons insulin resistant.  With other research showing that levels of brain insulin and its related receptors are lower in individuals with Alzheimer's disease, the Northwestern study sheds light on the emerging idea that Alzheimer's just may be a "type 3" diabetes.

Chilling stuff, but it does open up new research lines for treating Alzheimer’s disease, which up until now has been pretty much untreatable.  Are known diabetics who control their diabetes less prone to develop Alzheimer’s?  This research doesn’t address that question, but with both diseases becoming epidemic, I suspect the studies are already underway!

OUCH!  THAT HURTS!
And now a story that’s a little more upbeat.  Many of you suffer from migraines or know someone who does.  These ‘one-sided’ headaches are nasty and debilitating.  Thanks to new research, relief from the pain, nausea and other awful symptoms of migraine could be just a sniff away, as researchers have developed an inhalable medication for a condition that affects an estimated 30 million people in the United States.

A class of compounds called triptans, which target dilation of brain arteries, now are the mainstays for fighting migraines since the cause of these headaches is a reduction of blood flow to the brain.  Although triptans are effective, they tend to work slowly and are risky for individuals with heart disease.
The new treatments being developed target signaling proteins in the brain, including a receptor for a neuropeptide and a type of ion channel.  In laboratory studies, these drugs have fewer side effects than the triptans.

One exciting approach currently in clinical trials involves using a cell-phone sized device that is triggered by the airflow from inhaling.  The inhaler delivers a migraine drug in a user-friendly way and is faster-acting than conventional treatments.  So you migraine sufferers out there may not have to suffer too much longer!

NO, IT DOESN’T!
And now I have wonderful news for all you children out there.  And if you’re not a child, I’m sure you know one you can pass this along to.  It also has implications for the diabetics mentioned in the first story.  All of us have negative connotations with needles.  My mother told me that when I was a child, whenever I saw any woman in a white dress I would start to cry because most women in white dresses poked me with needles.

Now university researchers have developed something called ‘micro-needles’ and say that they are a safer and less painful way of delivering vaccines and other medicines than a conventional hypodermic syringe.  Micro-needles are specifically designed to avoid pain receptors and blood vessels. Researchers found that healthy volunteers reported less pain and sensation when they were injected with an array of micro-needles than with a hypodermic syringe.  Volunteers received an injection by one of two types of micro-needle and were then asked to complete a pain scale assessment and describe the injection sensation to gauge the impact of the different injection methods. The level of pain was perceived to be five times lower with micro-needles than with a conventional hypodermic needle and syringe.  The study also provided unique information on skin healing following micro-needle puncture.

A micro-needle array atop an English penny

I, for one, will be ecstatic if they never poke another needle into me again!  Hooray for medical research!

I SEE YOU!
All of the miniaturization that is taking place in the computer world is being integrated into biology research as well.  A new technique developed by Oxford University zoologists enables researchers to ‘hitch a ride’ with wild birds and witness their natural and undisturbed behavior.

The scientists developed miniaturized video cameras with integrated radio-tags that can be carried by wild, free-flying birds.  Using this new ‘video-tracking’ technology, they spied on the behavior of New Caledonian crows, a species renowned for its sophisticated use of tools, recording behaviors never seen before.

Observing New Caledonian crows in the wild is extremely difficult because they are easily disturbed and live in densely forested, mountainous terrain. ‘ Video-tracking’ enabled the Oxford scientists to obtain particularly intimate observations of crow behavior.

Scientists had always thought New Caledonian crows used tools mainly to probe into holes and cracks in rotting wood and tree crowns, but the Oxford researchers discovered they use tools even on the ground. 

One crow was seen probing leaf litter with grass-like stems – a mode of tool use, and a tool material, that researchers had missed, even after decades of observation. For the study, 18 crows were fitted with ‘tailcams’ that were only slightly heavier than a conventional radio-tag.  The units were attached to two tail feathers with strips of adhesive tape, and didn’t affect the bird’s movements.  They could be removed by the crows themselves and would last only until the bird’s next molt when the feathers fell off naturally. Who knows what animal the researchers will spy on next and what cool and unknown behavior they will discover?

A New Caledonian crow eats fruit in this still from the video camera attached to his tail.

And now a couple of stories from space

IN SPACE YOU CAN’T HEAR THE HISSING
Although it’s certainly taking much longer than I had hoped; we’re finally moving out into the final frontier.  The International Space Station has been continuously occupied for seven years now and as was the case with the Russian Mir space station; the ISS has developed some leaks.

Leaks are deadly in space if you lose all your air, but what if the leak is a tiny one.  Then you get a tiny leak of pressurized air.  Fixing them is easy, but finding them can be very hard.

The International Space Station is full of life-support systems, computers, controls, gear and research equipment.  All these things can hide a leak.  Leaks are also hard to find because astronauts can't hear the telltale hiss of escaping air.  That hiss is blowing outside the spacecraft and away from searching ears.  But a spacecraft can only produce so much oxygen and NASA can't afford for it to slowly and steadily blow into the cold vacuum of space.

Iowa State researchers have teamed with NASA to develop a sensor that can find leaks by detecting the small vibrations in a spacecraft's skin caused by escaping air.  The square instrument is about an inch across and includes an array of 64 elements that detect vibrations as they radiate along the spacecraft.

The different elements pick up the vibrations at different times.  The differences are then analyzed by a computer to determine the direction of the leak.  Add information from multiple sensors and a leak can be found in about a minute.  It can take weeks to find a leak with NASA's current handheld, ultrasonic detection devices.  So hats off to the Iowa State scientists for helping to keep our astronauts safe.

BLACK AND WHITE
	One of the most enduring solar system mysteries is the bizarre appearance of Saturn’s Moon Iapetus.  We’ve known for years that the Moon is half black and half white and the line between the shades is as sharp as a razor.  Cassini, the robot spacecraft in orbit around Saturn, has also taken images that show that Iapetus has a 12-mile tall ridge that circles the Moon at the equator.  I call Iapetus the Death Star Moon and have written a piece about it for this column.  You can find it in the archives here or on the Planetarium website In September the Cassini spacecraft flew close to Iapetus and NASA scientists are on the trail of Iapetus' mysterious dark side, which seems to be home to a bizarre "runaway" process that transports vaporized water ice from the dark areas to the white areas of the Saturnian moon.
Cassini captures the first high-resolution glimpse of the bright trailing hemisphere of Saturn's moon Iapetus in this false-color mosaic, which shows the entire hemisphere of Iapetus. (Credit: NASA/JPL/Space Science Institute)

Heat sensors on Cassini confirm that the dark material is warm enough (approximately minus 230 degrees Fahrenheit) for very slow release of water vapor from water ice, and this process is probably a major factor in determining the distinct brightness boundaries.

Scientists are slowly piecing together a complex story to explain the bright and dark faces of Iapetus but they still don’t know where the dark material is coming from.  Is it native to Iapetus or does it arrive from somewhere else?  Current theories were that this material did not originate from within Iapetus, but instead came from other moons orbiting at a much greater distance from Saturn in a direction opposite to Iapetus.  Scientists are beginning to believe that the darkening process did begin this way, but thermal have caused the extreme contrast we see today.

Once the leading side was even slightly dark from materials from other moons then, thermal segregation can proceed rapidly.  A dark surface absorbs more sunlight and warms up so the water ice on the surface evaporates.  The water vapor then condenses on the nearest cold spot, which could be Iapetus's poles, and possibly bright, icy areas at lower latitudes on the side of the moon facing in the opposite direction of its orbit.  So the dark stuff loses its surface ice and gets darker, and the bright stuff accumulates ice and gets brighter, in a runaway process.  Scientists say the result is that there are virtually no shades of gray on Iapetus. There is only white and very dark.

Because of the presence of very small craters that reveal the bright ice beneath, scientists also believe that the dark material is thin, a result consistent with previous Cassini radar results.  But some local areas may be thicker.  The dark material seems to lie on top of the bright region, consistent with the idea that it is a residual left behind by the sublimated water ice.

Some other mysteries are coming together.  There are more data on the signature mountain ridge that gives Iapetus its "walnut" appearance.  In some places the ridge is much lower and of course, the big question that remains is: Why doesn’t it go all the way around?

Was it partially destroyed after it formed, or did it never extend all the way around the moon?  Scientists think the ridge is very old because it’s pitted with craters.  One theory was that it was a ring of material around Iapetus that collapsed onto the surface, but the new pictures show that it’s way too solid and BIG to have been caused by a collapsing ring.  The ring theory also can’t explain features that look like tectonic structures in the new high-resolution images.

Over the next few months, scientists hope to learn more about Iapetus' mysteries.  And I’ll tell you all about what they discover!