Science Scanner: Need a Bone? Just Print One!

Posted November 30th, 2011 at 11:30 pm (UTC-4)
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If someone told you they’d created a material  that looks and feels like bone on an ink-jet printer, you’d probably laugh.

But researchers at  Washington State University have done just that.  The researchers used a 3D printer to create a bone-like material and structure that they say can be used in applications such as orthopedic procedures, dental work, and as a way to deliver medicine for treating osteoporosis.  When paired with actual bone, this newly produced material acts as a scaffold for new bone to grow on and, ultimately, dissolves with no apparent ill effects.

Reporting in the journal Dental Materials, the researchers say they’ve been successful with in-vitro tests (inside a test tube) and that they’re already seeing promising results with in-vivo (inside a living body) tests on rats and rabbits.

They think it’s possible doctors will be able to custom order replacement bone tissue in a few years.

The printer that produces this bone-like material works by having an ink-jet spray a plastic binder over a bed of powder in layers. Each  layer is about half the width of a human hair. Following a computer’s directions, it creates a channeled cylinder the size of a pencil eraser.

And, after just a week in a medium with immature human bone cells, the scaffold produced by the manufactured material supported a network of new bone cells.

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Ravens use gestures to communicate

A raven (Corvus corax) (Photo: Accipiter (R. Altenkamp, Berlin))

A raven (Corvus corax) (Photo: Accipiter (R. Altenkamp, Berlin))

Along with our voices, humans also communicate with each other via non-vocal signals such as gestures.  When we want to attract someone’s attention to something, it’s not uncommon for us to point or hold up an object we’d like someone to look at.

The only other creatures, scientists say, that have been observed using these visual signals, called deictic gestures, are our closest genetic relatives, the great apes.

Now, two researchers say they have evidence that ravens also use  various attention-grabbing gestures to test the interest of a potential partner or to strengthen an already existing relationship.

Over a two-year period, researchers from the Max Planck Institute for Ornithology and the University of Vienna, studied the non-vocal behavior of  a wild raven community in the Cumberland Wildpark in Grünau, Austria.

The researchers, Simone Pika und Thomas Bugnyar, noticed ravens use their beaks as we humans would use our hands to show and offer objects such as moss, stones and twigs.  They found the ravens predominantly aimed these gestures at their partners of the opposite sex, which resulted in frequent recognition between the signaler and recipient.

After this exchange of gestures, the ravens interacted with each other, for example, by example billing or joint manipulation of the object.

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Eradicating polio might prove more challenging than thought

Young girl in Conakry, Guinea getting her polio vaccine. (Photo: Julien Harneis on Flickr)

Young girl in Conakry, Guinea getting her polio vaccine. (Photo: Julien Harneis on Flickr)

While world health officials have largely reached their goal of eliminating polio worldwide, actually declaring the disease completely eradicated may be far more difficult, according to a report in the Journal of General Virology.

Scientists say strong evidence is needed to show that the actual virus that causes polio has disappeared completely.  Further research into the complex virus – such as host interactions and how the vaccine is used in the final stages of the eradication program – will be needed.

Outbreaks of polio or poliomyelitis, also known as infantile paralysis, caused waves of fear around the world throughout the 1950s.  However,  by the mid 1970s, thanks to strident vaccination programs, the viral disease was under control, and had been eradicated from the developed world.

In 1988, The World Health Organization launched a global eradication program, which is now nearing completion.

At the beginning of the 21st century, countries in the Indian subcontinent and central Africa were the only nations where polio was still endemic. And for the first time, India reported no cases of polio this year.

Health experts say that only three countries, Nigeria, Pakistan and Afghanistan still have the polio virus circulating.

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Our galaxy loves to eat

Our own Milky Way galaxy is one hungry galaxy, devouring its small neighboring dwarf galaxies, according to astronomers from Cambridge University.

The team discovered two streams of stars, in the Milky Way’s southern galactic hemisphere, that were torn off the Sagittarius dwarf galaxy.

They found that these new star streams connect with two previously-known streams in the northern galactic hemisphere. The research team came to their conclusions from analyzing data from the latest Sloan Digital Sky Survey (SDSS-III).

“We have long known that when small dwarf galaxies fall into bigger galaxies, elongated streams, or tails, of stars are pulled out of the dwarf by the enormous tidal field,” research team co-leader Sergey Koposov said.

Astronomers say that, at one time, the Sagittarius dwarf galaxy was one of the brightest of those surrounding the Milky Way. Its disrupted remnant now lies on the other side of our galaxy, breaking up as it is crushed and stretched by huge tidal forces. In fact, the Sagittarius dwarf galaxy is so small that it has lost half of its stars and all of its gas over the last billion years.

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Rick Pantaleo
Rick Pantaleo maintains the Science World blog and writes stories for VOA’s web and radio on a variety of science, technology and health topics. He also occasionally appears on various VOA programs to talk about the latest scientific news. Rick joined VOA in 1992 after a 20 year career in commercial broadcasting.

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