Engineers at MIT have designed the first simple process for manufacturing materials that strongly repel oils. The material, which can be applied as a flexible surface coating, could have applications in aviation, space travel and hazardous waste cleanup.
For example, the material could be used to help protect parts of airplanes or rockets that are vulnerable to damage from being soaked in fuel, such as rubber gaskets and o-rings, Physorg.com said.
“These are vulnerable points in many aerospace applications“ said Robert Cohen, the St. Laurent Professor of Chemical Engineering and an author of a paper on the work that will appear in the Dec. 7 issue of Science.
“It would be nice if you could spill gasoline on a fabric or a gasket or other surface and find that instead of spreading, it just rolled off,“ Cohen said.
Creating a strongly oil-repelling, or ’oleophobic’ material, has been challenging for scientists, and there are no natural examples of such a material.
“Nature has developed a lot of methods for waterproofing, but not so much oil-proofing,“ said Gareth McKinley, MIT School of Engineering Professor of Teaching Innovation in the Department of Mechanical Engineering and a member of the research team.
“The conventional wisdom was that it couldn’t be done on a large scale without very special lithographic processes.“
The tendency of oils and other hydrocarbons to spread out over surfaces is due to their very low surface tension (a measure of the attraction between molecules of the same substance).
Water, on the other hand, has a very high surface tension and tends to form droplets. For example, beads of water appear on a freshly waxed car (however, over a period of time, oil and grease contaminate the surface and the repellency fades).
That difference in surface tension also explains why water will roll off the feathers of a duck, but a duck coated in oil must be washed with soap to remove it.
The MIT team overcame the surface-tension problem by designing a material composed of specially prepared microfibers that essentially cushion droplets of liquid, allowing them to sit, intact, just above the material’s surface.
When oil droplets land on the material, which resembles a thin fabric or tissue paper, they rest atop the fibers and pockets of air trapped between the fibers.
The large contact angle between the droplet and the fibers prevents the liquid from touching the bottom of the surface and wetting it.
The microfibers are a blend of a specially synthesized molecule called fluoroPOSS, which has an extremely low surface energy, and a common polymer.
They can be readily deposited onto many types of surfaces, including metal, glass, plastic and even biological surfaces such as plant leaves, using a process known as electrospinning.

Scientists have gotten their best look ever at interactions inside human skin cells, finding a Velcro-like setup that links them and makes skin strong while also supple.
The cell-interior images, made with a new a technique called cryo-electron tomography, show the proteins responsible for cell-cell contacts for the first time, LiveScience.com said.
“This is a real breakthrough in two respects,“ said Achilleas Frangakis of the European Molecular Biology Laboratory.
“Never before has it been possible to look in three dimensions at a tissue so close to its native state at such a high resolution. We can now see details at the scale of a few millionths of a millimeter. In this way we have gained a new view on the interactions of molecules that underlie cell adhesion in tissues--a mechanism that has been disputed over decades.“
The results are detailed in the Dec. 6 issue of the journal Nature.
So far, the only information available about a protein’s position and interactions in a cell was based on either light microscopy images at poor resolution or techniques that remove proteins from their natural context. Electron microscopy normally requires tissue to be treated with chemicals or coated in metal, a procedure that disturbs the natural state of a sample.
Frangakis and his group developed a technique that instantly freezes cells in their natural state prior to imaging with an electron microscope.
With cyro-electron tomography, images of the untreated sample are taken from different directions and assembled into an accurate 3-D image by a computer.
The researchers applied this technique to observe proteins that are crucial for the integrity of tissues and organs such as the skin and heart, but also play an important role in cell proliferation.
These proteins, called cadherins, are anchored in cell membranes and interact with each other to bring cells close together and interlink them tightly.
“We could see the interaction between two cadherins directly, and this revealed where the strength of human skin comes from,“ says Ashraf Al-Amoudi, who carried out the work in Frangakis’ lab.
“The trick is that each cadherin binds twice: once to a molecule from the juxtaposed cell and once to its next-door neighbor. The system works a bit like specialized Velcro and establishes very tight contacts between cells.“

The ancient kangaroo had opposable ÔbigÕ toes and flexible feet, a sign it had some climbing ability.

A 25-million-year-old fossil has revealed that a predecessor of Australia’s iconic hopping kangaroo once galloped on all fours, had dog-like fangs and possibly climbed trees, scientists have reported.
“This is really the great, great, great, great grandfather of modern kangaroos,“ a member of the Australian team that analyzed the bones, La Trobe University paleontologist Ben Kear said.
According to AFP, the near-complete skeleton of the prehistoric kangaroo was found in Queensland state in the 1990s and represents a new species called nambaroo gillespieae, Kear said.
The ancient animal is part of an extinct group of kangaroos known as the balbaridae, which is believed to have been replaced over time by the direct ancestors of modern kangaroos.
Kear said the study found the nambaroo, which was about the size of a small dog and had canine fangs, had “big, muscly forearms“ that showed it galloped or bounded like a brush-tailed possum.
The ancient kangaroo also had opposable ’big’ toes and flexible feet, a sign it had some climbing ability, like modern tree kangaroos. It lived in dense forest, which suggests a diet of fruit and fungi.
“You’ve got this primitive kangaroo, imagine it’s climbing low branches, bounding around the forest floor, eating fungi, eating fallen fruit,“ Kear said.
“It’s very different to what we would imagine from your average kangaroo... that you see today.“
Kear said the nambaroo skeleton would help scientists learn more about how climate change affected the evolution of kangaroos over millions of years.
It is thought kangaroos evolved into larger animals that hopped and ate grass as the landscape became drier and grassy plains appeared about 10 to 15 million years ago.
“Looking at a skeleton like this is the Rosetta Stone, it’s the quintessential fossil that will give you the beginning of the whole kangaroo radiation,“ Kear said.

Dutch researcher Bas Bougie has developed a laser system to investigate soot development in diesel engines. Small soot particles are not retained by a soot filter but are, however, more harmful than larger soot particles.
Therefore, soot development needs to be tackled at the source. Laser Induced Incandescence is a technique that reveals exactly where soot is generated and can be used by project partners to develop cleaner diesel engines, ScienceDaily said.
Measuring soot formation in a diesel engine is far from easy. Due to the turbulent environment in the combustion cylinder, no two combustion cycles are the same. Furthermore, the measurements are difficult to reproduce as the pressure at which fuel is injected into the cylinder causes an extra source of turbulence.
Bougie made his measurements in a glass cylinder with an engine adapted for this purpose.
Laser Induced Incandescence (LII) can be used to investigate optimal engine conditions that reduce soot emission from the engine. LII can be deployed in different types of engines and with different fuels.
Bougie carried out measurements during higher and lower loading of the engine and for two different fuel injection systems: a line pump system and a common rail system.
Neither the engine load nor the injection system was found to affect the primary particle size of the soot emitted. However, there are many other motor settings that can lead to an improvement in the combustion.
The results of the measurements can now be used to verify existing combustion models at Eindhoven University of Technology.
Together with the STW users’ committee (participants are: DAF, Eindhoven University of Technology, Delft University of Technology, the University of Twente, Cyclone Fluid dynamics, Royal Netherlands Naval College, TNO and Shell), Eindhoven University of Technology will investigate further improvements to the measuring system with the ultimate objective of producing cleaner diesel engines.

Solar wind is a stream of electrically charged gas blown outward from the sun in all directions.

The solar wind, which whips off the sun and blows past Earth and through the solar system, is unleashed by powerful magnetic waves in electrically charged gas around the sun, scientists said.
The mechanisms that cause the solar wind had baffled scientists for decades, but were revealed in observations by a Japanese satellite called Hinode orbiting Earth, the scientists said in research published in the journal Science, according to Reuters.
“The magnificent thing about the success of Hinode is its unprecedented view of the dynamics of the sun,“ Jonathan Cirtain, a solar physicist at NASA’s Marshall Space Flight Center, Huntsville, Alabama, who helped in the research, said in a telephone interview.
The research was conducted by Japanese, European and US scientists.
The solar wind is a stream of electrically charged gas--mostly hydrogen--blown outward from the sun in all directions at a speed of about a million mph (1.6 million kph).
It buffets planetary atmospheres. On Earth, it can disrupt satellites, power grids and communications, under certain circumstances. Earth’s magnetic field protects against the solar wind, creating a bubble around which the wind must flow.
Driving the solar wind are so-called Alfven waves--strong magnetic waves--that ripple through the plasma of the sun’s atmosphere, or corona, transferring energy from the star’s surface and into the solar wind, the researchers said.
The waves are named after Swedish physicist Hannes Alfven, whose prediction of their existence helped earn him a Nobel prize in physics 1970. He died in 1995.
Hinode (pronounced hin-OH-day and named for the Japanese word for “sunrise“) showed that two mechanisms appear to power the solar wind, Cirtain said.
The first involves the way the sun’s magnetic field undergoes rapid changes in its shape, the researchers said. As the magnetic field changes shape, it generates these Alfven waves along its length that accelerate the charged gas and blow it into space, they said.
Another mechanism powering the solar wind involves the sun’s chromosphere, the region sandwiched between the solar surface and its corona. Images from Hinode’s Solar Optical Telescope found that the chromosphere is filled with Alfven waves, which when they leak into the corona are strong enough to trigger the solar wind.
“Until now, Alfven waves have been impossible to observe because of limited resolution of available instruments,“ Alexei Pevtsov, Hinode program scientist for NASA, said in a statement.
The Japan Aerospace Exploration Agency leads the mission, with cooperation from NASA and the European Space Agency.

One reason that some people seem unable to learn from their mistakes has been pinpointed by scientists.
A spelling mistake in the DNA of a gene within the brain seems to impair the ability of a person to improve their performance based on knowledge of earlier errors, according to Telegraph.co.uk.
The findings may also help explain why this same variant has previously been linked to addictive and compulsive behaviors, according to the German team.
When people inherit this variation of the gene, called A1, they make fewer docking points in the brain for a chemical called dopamine, one that carries messages between brain cells and plays a key role in movement, balance and in reward and pleasure circuits.
The discovery, reported in the journal Science, was made when two groups of healthy men, one that carried the A1 variant and one that did not, were compared by Tilmann Klein, Dr Markus Ullsperger and colleagues of the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, Germany and Max-Planck-Institute for Neurological Research, Cologne, with colleagues at the universities of Bonn and Giessen.
The volunteers were shown pairs of symbols in random order and were supposed to figure out which symbols they were supposed to choose, based on whether they received positive or negative feedback after each successive choice, given in the form of smiling or frowning faces.
The tests showed that volunteers with the A1 variant were less successful at learning to avoid mistakes, implying that they responded less to negative feedback than the volunteers in the other group.
Brain scan studies also supported this result, revealing that in the A1 carriers, a reduced ability to learn from errors was accompanied by diminished activity in a brain area already known to monitor for errors, called the posterior medial frontal cortex.
Thirty percent of people carry at least one copy of A1 and three percent may carry two. “One has to be cautious be saying that 30 per cent are affected--we just found that they have problems in learning to avoid negative action outcomes. But the situation we tested them was an artificial laboratory setting. Therefore more research is needed to show how our findings apply to real world situations,“ Klein tells The Daily Telegraph.
But as for whether bosses will ever use this understanding to screen workers for their propensity to make cock-ups, more research will be necessary, Klein says.

It is possible to die from a broken heart, mounting evidence shows. A review of recent work, published in The Lancet, found that the risk of death increases by up to a fifth following bereavement.
Investigator Margaret Stroebe of Utrecht University, The Netherlands, said the psychological distress caused by the loss played a big part, BBC said.
Heart experts say people who lose a close significant person often adopted unhealthy habits such as smoking and poor diet.
Experts know psychological stress can cause physical changes in the body--stress hormones can disrupt body processes.
One study found men were 21 percent more likely to die after the loss of their wife. Widows had a 17 percent increased risk of death.
The risk appears to be highest in the early weeks following bereavement and decreased with time.
Men who lose a wife are also three times more likely to take their own life. Widows, however, do not have an increased suicide risk.
A Danish study from 2003 showed fathers and mothers have a raised suicide risk after the death of a child, a risk which is higher the younger the child and is particularly high in the first 30 days post-bereavement.
Dr Stroebe’s team said, “The patterns are quite consistent, enabling the conclusion that the mortality of bereavement is attributable in large part to a so-called broken heart, the psychological distress due to the loss.“
But they stressed that most people cope with grief without professional help.
Most reactions are not complicated and for most bereaved people, family and friends, religious and community groups, and various societal resources will provide the necessary support, the researchers said.
Rev Dr Peter Hammersley of Cruse Bereavement Care said, “This phenomenon has been recognized for some time.
Loss of a close significant person is a severe experience for the bereaved person who is left.