Scientists Produce World's First Magnetic Soap

                                         The liquid crystal progression of each surfactant was investigated by the solvent penetration method (i.e. phase cut). A small amount of surfactant was placed on a microscope slide under a coverslip. The slide was mounted on the cover slide and heated until the sample was fluid and completely isotropic. After slow cooling (1.0 °C min-1) to 25 °C, a drop of water was added to the edge of the coverslip. As the water penetrated the surfactant, a concentration gradient was established, from water at one side to pure surfactant at the other, enabling the entire range of mesophases to be observed in the field of view. (Credit: Image courtesy of Institut Laue-Langevin (ILL))                                  ScienceDaily  — Scientists from Bristol University have developed a soap, composed of iron rich salts dissolved in water, that responds to a magnetic field when placed in solution. The soap’s magnetic properties were shown with neutrons at the Institut Laue-Langevin to result from tiny iron-rich clumps that sit within the watery solution. The generation of this property in a fully functional soap could calm concerns over the use of soaps in oil-spill clean ups and revolutionise industrial cleaning products.

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Scientists have long been searching for a way to control soaps (or surfactants as they are known in industry) once they are in solution to increase their ability to dissolve oils in water and then remove them from a system. The team at Bristol University have previously worked on soaps sensitive to light, carbon dioxide or changes in pH, temperature or pressure. Their latest breakthrough, reported in Angewandte Chemie, is the world’s first soap sensitive to a magnetic field.
Ionic liquid surfactants, composed mostly of water with some transition metal complexes (heavy metals like iron bound to halides such as bromine or chlorine) have been suggested as potentially controllable by magnets for some time, but it had always been assumed that their metallic centres were too isolated within the solution, preventing the long-range interactions required to be magnetically active.
The team at Bristol, lead by Professor Julian Eastoe produced their magnetic soap by dissolving iron in a range of inert surfactant materials composed of chloride and bromide ions, very similar to those found in everyday mouthwash or fabric conditioner. The addition of the iron creates metallic centres within the soap particles.
To test its properties, the team introduced a magnet to a test tube containing their new soap lying beneath a less dense organic solution. When the magnet was introduced the iron-rich soap overcame both gravity and surface tension between the water and oil, to levitate through the organic solvent and reach the source of the magnetic energy, proving its magnetic properties.
Once the surfactant was developed and shown to be magnetic, Prof Eastoe’s team took it to the Institut Laue-Langevin, the world’s flagship centre for neutron science, and home to the world’s most intense neutron source, to investigate the science behind its remarkable property.
When surfactants are added to water they are known to form tiny clumps (particles called micelles). Scientists at ILL used a technique called “small angle neutron scattering (SANS)” to confirm that it was this clumping of the iron-rich surfactant that brought about its magnetic properties.
Dr Isabelle Grillo, responsible of the Chemistry Laboratories at ILL: “The particles of surfactant in solution are small and thus difficult to see using light but are easily revealed by SANS which we use to investigate the structure and behaviour of all types of materials with typical sizes ranging from the nanometer to the tenth of micrometer.”
The potential applications of magnetic surfactants are huge. Their responsiveness to external stimuli allows a range of properties, such as their electrical conductivity, melting point, the size and shape of aggregates and how readily its dissolves in water to be altered by a simple magnetic on and off switch. Traditionally these factors, which are key to the effective application of soaps in a variety of industrial settings, could only be controlled by adding an electric charge or changing the pH, temperature or pressure of the system, all changes that irreversibly alter the system composition and cost money to remediate.
Its magnetic properties also makes it easier to round up and remove from a system once it has been added, suggesting further applications in environmental clean ups and water treatment. Scientific experiments which require precise control of liquid droplets could also be made easier with the addition of this surfactant and a magnetic field.
Professor Julian Eastoe, University of Bristol: “As most magnets are metals, from a purely scientific point of view these ionic liquid surfactants are highly unusual, making them a particularly interesting discovery. From a commercial point of view, though these exact liquids aren’t yet ready to appear in any household product, by proving that magnetic soaps can be developed, future work can reproduce the same phenomenon in more commercially viable liquids for a range of applications from water treatment to industrial cleaning products.”
Peter Dowding an industrial chemist, not involved in the research: “Any systems which act only when responding to an outside stimulus that has no effect on its composition is a major breakthrough as you can create products which only work when they are needed to. Also the ability to remove the surfactant after it has been added widens the potential applications to environmentally sensitive areas like oil spill clean ups where in the past concerns have been raised.”

Scientists keep their eyes on peripheral vision

USC Dornsife's Bosco S. Tjan (above) and USC graduate student Anirvan S. Nandy theorized in a new paper that peripheral vision is hindered by the visual experience formed in the brain during eye movements. Credit: Dietmar Quistorf. (Medical Xpress) -- Two USC scientists are bringing peripheral vision into focus, showing that the way the brain sharpens its attention while the eyes are in motion leads to false assumptions about how objects should look.
The eye’s photoreceptors — the cells that detect light — are clustered at the center of the field of vision, leaving the periphery like a low-resolution camera. USC Dornsife neuroscientist Bosco S. Tjan and USC graduate student Anirvan S. Nandy theorized that peripheral vision is hindered by the visual experience formed in the brain during eye movements.
Their paper was published online on Jan. 8 in Nature Neuroscience.
According to the researchers, a single neural signal directs the eyes to look at an object of interest in the periphery and causes the brain to start paying attention to that object. Unless they are tracking an object — such as a police officer’s penlight during a sobriety test — human eyes do not tend to move in fluid motions. Instead, they jump from one point of focus to another in a jerky fashion called “saccadic” eye movement.
Those movements bring an object into the center of the field of vision. The brain actually starts paying attention to that object — “turning on” its ability to learn about it — shortly before the eyes move and lock on to it.
The researchers said this makes the version of the visual world that the brain learns from the periphery appear smeared.
“Parts of the brain that process peripheral vision assume these smears were typical of the physical world and make corresponding perceptual errors that cannot be explained by merely seeing the world in low resolution,” said Tjan, associate professor of psychology.
Vision is based, in part, on assumptions made by the brain. For example, if you look at a coffee mug, your brain sees one side of it and assumes that the rest is completely round — when in fact the back side that you do not see could be almost any shape at all, to a certain point.
“For the brain to see things, generally speaking, it has to make assumptions about the world,” Tjan said.
(Mis)guided by the peripheral vision’s smeared version of the world, the brain would have a hard time recognizing objects in the periphery and be more prone to error. Tjan and Nandy’s theory explained a wealth of empirical data on peripheral vision gathered in the last few decades.
Tjan said he hopes their work will help inform therapy for patients suffering from diseases like macular degeneration, in which damage to the retina costs patients sight at the center of the field of vision.
Macular degeneration is, for the moment, irreversible. Patients with macular degeneration are retaught how to see by focusing their attention outside the center of their field of vision — a difficult task, given the poor quality of the image with which they are left.

“At least for now, the best we can hope for is to train a patent to use [his or her] periphery. But to do that, we need to know why the periphery is so much worse,” Tjan said.

The research was supported by the National Eye Institute of the National Institutes of Health.
Provided by USC College
"Scientists keep their eyes on peripheral vision." January 20th, 2012. http://medicalxpress.com/news/2012-01-scientists-eyes-peripheral-vision.html

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