These particles have come a long way.

Scientists already knew that microplastics—polymer beads, fibers, or fragments less than 5 millimeters long—can wind up in the ocean, near coastlines, or in swirling eddies such as the Great Pacific Garbage Patch. But Rachel Obbard, a materials scientist at Dartmouth College, was shocked to find that currents had carried the stuff to the Arctic.

In a study published online this month in Earth’s Future, Obbard and her colleagues argue that, as Arctic ice freezes, it traps floating microplastics—resulting in abundances of hundreds of particles per cubic meter. That’s three orders of magnitude larger than some counts of plastic particles in the Great Pacific Garbage Patch. “It was such a surprise to me to find them in such a remote region,” she says. “These particles have come a long way.”

The potential ecological hazards of microplastics are still unknown. But the ice trap could help solve a mystery: Industrial plastic production has increased markedly in the last half-century, reaching 288 million tonnes in 2012, according to Plastics Europe, an industry association. But ecologists have not been able to account for the final disposition of much of it. The paper shows that sea ice could be an

important sink—albeit one that is melting, says Kara Lavender Law, an oceanographer at the Sea Education Association in Woods Hole, Massachusetts, who was not part of the study. “There could be freely floating plastics, in short order.” The authors estimate that, under current melting trends, more than 1 trillion pieces of plastic could be released in the next decade.

Obbard and her colleagues based their counts on four ice cores gathered during Arctic expeditions in 2005 and 2010. The researchers melted parts of the cores, filtered the water, and put the sediments under a microscope, selecting particles that stood out because of their shape or bright color. The particles’ chemistry was then determined by an infrared spectrometer. Most prevalent among the particles was rayon (54%), technically not a synthetic polymer because it is derived from natural cellulose. The researchers also found polyester (21%), nylon (16%), polypropylene (3%), and 2% each of polystyrene, acrylic, and polyethylene. Co-author Richard Thompson, a marine biologist at the University of Plymouth in the United Kingdom, says it’s difficult to pinpoint the source of these materials. Rayon, for instance, can be found in clothing, cigarette filters, and diapers.

Abundances are likely to grow as scientists learn to sift more finely. Law points out that microplastic estimates for the Great Pacific Garbage Patch are based on phytoplankton nets that catch only particles bigger than 333 microns. Obbard, who used a much smaller 0.22 micron filter, says she still probably missed many particles herself; searching by eye, she easily could have missed brownish or clear plastic particles that were masquerading as sand grains.

What is the consequence of all this plastic floating around? At this point, it is hard to say. Plastic is chemically inert. But the plastic can absorb organic pollutants in high concentrations, says Mark Browne, an ecologist at the University of California, Santa Barbara. Browne has performed laboratory experiments with marine organisms showing not only how the microplastics can be retained in tissues, but also how pollutants might be released upon ingestion. “We’re starting to worry a bit more,” he says.

Such a high reliability of the materials.

As the electronic equipment function is more and more strong, the body is more and more small, heat dissipation problems have become more and more complicated. Engineers have been looking for a better thermal interface materials, effective heat dissipation to help electronic equipment. Amorphous polymer material is a poor conductor of heat, because their disorder limits the heat conduction transfer of phonons. In the polymer can be used to create neat crystal structure to improve its thermal conductivity, but the structure is formed by fiber drawing process, can lead to brittle materials.
George woodruff school of mechanical engineering at Georgia tech, said barak figure DE carat, assistant professor of new thermal interface material is made by using conjugated polymer poly (thiophene and its neat nanofiber arrays are not only good for transfer of phonon, and avoid the brittleness of materials. New materials in the thermal conductivity at room temperature is 4.4 w/m, kelvin, and has set up 80 times in 200 ℃ temperature thermal cycle test, performance remained stable; Between the chip and heat sink, by contrast, commonly used solder thermal interface materials, work in the process of the high temperature of reflow may become unreliable.
Nanometer fiber array structure is made by multiple steps: researchers first electrolyte containing a single coated on a tiny pore alumina template, and then to the template applied potential, every pore of electrode will attract monomer, began to form hollow nanofibers. Fibre length and wall thickness by applying the electrical flow and time control, the diameter of the fiber is determined by the size of the pore, ranging from 18 nm to 300 nm. The thickness of the traditional thermal interface materials about 50 microns to 75 microns, and this way to get new material thickness can be thin to 3 microns.
Carat, said the technology still needs further improvement, but he believes that the future can expand production and commercialization. “Such a high reliability of the materials for solving the problem of heat dissipation is very attractive. The material may eventually change the way we design electronic system.”

A type of learning.

For the most part, the brain stops producing new neurons—a process called neurogenesis—soon after birth. In humans, mice, and some other species, however, neurogenesis continues throughout life in a brain region that encodes memories about space and events, called the dentate gyrus of the hippocampus. In adult humans, the dentate gyrus produces roughly 700 new brain cells each day.

Studies in mice have shown that suppressing neurogenesis can impair a type of learning called pattern separation, which allows us to distinguish between two similar but slightly different circumstances. One example is remembering where you parked the car from 1 day to the next, explains René Hen, a neuroscientist at Columbia University who was not involved in the new study.

Although the precise role of neurogenesis in memory is still controversial, more than a decade of research has demonstrated that boosting neurogenesis with exercise and antidepressants such as Prozac can increase rodents’ ability to learn new information about places and events. A few years ago, however, neuroscientist Paul Frankland of the Hospital for Sick Children in Toronto, Canada, noticed that some of the animals in his experiment actually did worse on certain memory tasks when their neuron birth rates had been ramped up. In particular, they performed poorly on tests that required them to retain details about past events.

The result was “way too interesting to ignore,” Frankland says. Because neurogenesis surges in newborn mice and humans and then tapers to a slow trickle by adulthood, Frankland and colleagues wondered if that explosion of new neurons could help explain the widespread phenomenon of infantile amnesia—the inability of adults to remember events that occurred before they were 2 to 4 years old. Some theoretical models suggested that new neurons destabilize memories already stored in the hippocampus by degrading the information there, but the idea had never been explored in live animals.