Bone growing on nanotube scaffold.

Every year, many people go into hospitals to receive a total knee replacement. For some, it’s a painful procedure with significant recovery time, says an article in sciencentral.com.
Materials scientist Robert Haddon from the University of California, Riverside thinks there may be another solution. He has been working with carbon nanotubes, which are so small, they’re 100,000 times finer than a human hair. He hopes that one day doctors might be able to inject these nanotubes into a knee, or another injury, where they would encourage damaged or broken bones to regrow.
While they may be tiny, these nanotubes are the “highest strength material known, yet extremely light in weight,“ Haddon says. Their carbon bond structure Ñ the same type of bonds that give diamonds their incredible strength Ñ is very similar to chicken wire that’s been rolled up into a cylinder.
“It’s a material of really unsurpassed performance,“ he says. “The strength of the material is many times that of steel but lighter in weight.“
Haddon says that nanotubes’ strength and light weight make them similar to a key component in the human skeleton, collagen. So, he proposed that nanotubes could serve as a good substitute for the collagen building blocks of bone.
Researchers at Riverside confirmed that bone cells would start to grow on the carbon nanotubes, which serve as the scaffold material for new bone growth.
The results are promising, but Haddon says that growing bone cells in a petri dish is very different than growing new bone in the body. The researchers are still trying to improve the process, which is costly and requires very high quality materials.

The chemical warning signals produced by fear improve cognitive performance, according to a study at Rice University in Houston.
Women who were exposed to chemicals from fear-induced sweat performed more accurately on word-association tasks than did women exposed to chemicals from other types of sweat or no sweat at all.
“It is well-documented in the research literature that animals experiencing stress and fear produce chemical warning signals that can lead to behavioral, endocrinological and immunological changes in their fellow animals of the same species, but we wanted to see if this applies to humans as well,“ principal investigator Denise Chen, assistant professor of psychology at Rice, told sciencedaily.com.
For the study, Chen collected samples of sweat from research volunteers who kept gauze pads in their armpits while they watched videos of horror movies and nonthreatening documentaries. The sweat samples were then stored in a freezer until needed for the study.
Next, Chen had 75 female students between the ages of 18 and 22 respond to 320 pairs of words that flashed for three seconds each on a computer screen. For each pair, the participants had to press a key to indicate whether the words were associated with each other (for example, arms and legs) or not (arms and wind). Some of the words were associated with threatening or fear-related topics, like weapons.
Each participant had a piece of gauze attached above their lips so that they were exposed to either chemicals from sweat or none at all during the tests. Chen compared how the chemicals from sweat impacted the speed and accuracy of participants’ results on the word-association tests.
When processing meaningfully related word pairs, the participants exposed to the fear chemicals were 85 percent accurate, and those in either the neutral sweat or the control condition were 80 percent accurate. Chen’s theory is that the chemicals from fear-induced sweat prompted subjects to be more cautious.

Hot Jupiters are huge planets that orbit nearer their stars than our closest planet, Mercury, orbits the Sun.

Habitable, Earth-like planets can form even after giant planets have barreled through their birthplace on epic migrations towards their host stars, new computer simulations suggest. The finding contradicts early ideas of how planets behave and suggests future space missions should search for terrestrial planets near known “hot Jupiters“.
Many of the 160 or so known extrasolar planets are hot Jupiters - massive planets that are closer to their stars than Mercury is to our Sun. But the planets probably did not form in these scorching regions because there would not have been enough gas and dust there to amass such giant worlds, explains newscientist.com.
That suggests the planets formed farther out and migrated towards their host stars as they lost energy due to friction with gas in their natal discs. But that migration was thought to prevent the formation of terrestrial planets. That is because the roving giants would hit or fling their rocky building blocks out of the planetary system.
But recent computer simulations have shown that up to half of the rocky bodies could survive in the planetary system during the 100,000 years it takes for the giant planet to migrate in to the star. Now, scientists have performed computer simulations to see how those rocky objects evolve over 200 million years.
Initially, the migration of the giant planets throws the objects out of the plane of the planetary system and moves them from circular to elliptical orbits. But then gas in the planet-forming disc forms a cushion, damping the effect of these crazy, chaotic orbits.
The objects then move back into flatter, more circular orbits and form terrestrial planets. Some of these planets orbit within the “habitable zone“ - a region around the star where liquid water can exist and which is therefore a potential haven for life.

Mayo Clinic researchers have uncovered a new cellular secret that may explain how certain cancers move and spread - a feature of cancers that makes treatment especially difficult. If the mechanism that drives cancer movement - also called metastasis - can be understood well enough to manipulate it, new and better treatments can be developed for patients with metastatic cancers.
According to sciencedaily.com, the Mayo findings are the first to show one role the waves play. They selectively round up activated growth-promoting proteins from the cell surface and take them to the interior of the cell. Under normal conditions, this process would help terminate signals from these growth-promoting proteins. However, in cancer cells it appears that either these waves may not function properly, or that the internalized proteins may remain active longer, which allows them to “instruct“ a cell to acquire cancerous traits such as excessive growth and invasive movement that constitute metastasis. These waves are important for helping to keep these cancer-growth commands at bay.
The researchers found that the waves store up to half the activated Epidermal Growth Factor Receptors (EGFR) from the surface of the cell and take this cache to the interior of the cells.
Cell growth and movement are vital topics in cancer research because cancer is a disease of uncontrolled cell growth in which the normal balance between growth promotion and growth inhibition is disrupted. Epidermal Growth Factor (EGF) and the EGFR to which it homes and docks are a hot topic in cancer research because EGF promotes growth through binding and activating its receptor and certain tumors exhibit elevated levels of EGFR. In addition, activated EGFR have been implicated in the development and spread of several human cancers, including cancers of the colon, ovary, breast and lung.