Building a Better Mosquito Trap

November 06, 2009

UC Davis scientists who have been sussing out mosquitoes’ sniffers have made a discovery that could lead to really killer bug traps.

Chemical ecologists Walter Leal and Zain Syed identified a chemical called nonanal in humans—and, crucially, birds—that serves as a signal for the Culex species of mosquito. Nonanal is a metabolic product of fatty acid, and while it's unclear what its function is for us, for hungry mosquitoes it's like a "BITE HERE" sign.

The scientists tested hundreds of compounds that birds and humans have and found that sensitive mosquito antennae can detect even minute amounts of nonanal. They used the chemical as a lure and waited to see how bloodsucking, West-Nile-Virus carrying Culex mosquitoes would react.

Leal says when they added carbon dioxide to nonanal, the combo attracted more mosquitoes than each of them combined. A heavy duty CO2 trap they put in nearby Yolo County caught around 2,000 of mosquitoes nightly. Leal says synthetic nonanal is dirt cheap to produce and he thinks that traps with it might be available next year. Next, the plan is to test other mosquito species' responses to the combo.

Sadly, an effective DEET alternative is still elusive. Blocking nonanal and CO2 means mosquitoes will find a different signal, Leal reports. He also told me that if he had an effective repellent that decreased human attraction to mosquitoes, he'd be first in line. "They give me a tremendous allergic reaction."

Photo: UC Davis chemical ecologists Walter Leal (left) and Zain Syed in the lab. Credit: Kathy Keatley Garvey/UC Davis Department of Entomology.

Supersurface Could Shrink Power Plants

November 04, 2009

Sounds trippy, but it's true: mushrooms and lotus leaves are the inspiration for a superhydrophobic surface created by Duke University scientists that has the potential to make power plants super-efficient.

"In power plants, the majority of the space is taken up by bulky condensers," says Chuan-Hua Chen, assistant professor of mechanical engineering and materials science at Duke. Conventional condensers, which are needed to reject heat in power plants' cooling systems, rely on slick coatings and gravity. Chen and his team turned to nature for better ideas.

Water rolls right off a lotus leaf because its rough surface traps air under the droplets. When a mushroom reproduces, the discharge of spores is actually powered by the energy released when dew droplets merge on them. To replicate these effects, the scientists etched pillars a few microns tall into silicon and added carbon nanotubes that mimic the rough lotus leaf. When cooled, the synthetic surface causes water droplets to form quickly and jump--like a balloon bouncing off your hand.

Chen says this makes a condenser so efficient that its size could be reduced as much as 10 times what it is now. Plus, the surface doesn't need gravity to work so it could even be used in outer space. A Duke University video shows it in action:

Grad student Jonathan Boreyko is leading work on building miniaturized condensers with the superhydrophobic surface. Chen says that while there are ways to make such surfaces inexpensively, the focus now is on durability. With supersurfaces, we could get more out of the power plants we've already got, making each drop truly count.

Photo: Chuan-Hua Chen (right) and Jonathan Boreyko (left), demonstrate the superhydrophobic surface, located under the pipette. Credit: Duke University Photography.

Traffic Control for Turtles

October 29, 2009

Scientists have been tagging turtles for a little while to see where they go, but a new combined effort could mean fewer turtle tragedies in the open water.

Juvenile loggerhead turtles, which are a threatened species, can unintentionally become bycatch on fishing vessels. In the fall, sometimes they enter water that's too cold and become stranded. Researchers from the U.S. Northeast Fisheries Science Center in Woods Hole, Massachusetts, are hot on the turtle trail, tracking their movements to better understand their behavior so fishermen can avoid them.

Working with support from the Atlantic sea scallop fishing industry, the NEFSC captured two juvenile turtles in August, attached satellite-linked tags to their carapaces, and has been tracking their movements since (they're off the coast of North Carolina now). The scientists also sent a remotely operated vehicle or ROV into the ocean to get visuals on turtle movements in the wild--the first time this has been done, according to the FEFSC. Here's a cool underwater video showing an ROV-view of a young loggerhead turtle.

The hope is that this pilot project leads to a larger turtle behavior study, as well as better fishing gear technology that prevents turtles from getting caught. That way we'll be able to keep on finding Nemo.

Photo: Attaching a satellite-linked data logger. Credit: Eric Matzen, NEFSC/NOAA.

When Is Bamboo...Rayon?

October 23, 2009

I've had the bamboo fiber pulled over my eyes. Following a settlement with a clothing maker, the Federal Trade Commission announced that fabrics made from processed bamboo can't be pedaled as green--they're as synthetic as the rayon shirt hiding in your closet.

Under the FTC's settlement terms, retailer Bamboosa agreed not to make any environmental claims about its bamboo textiles being biodegradable, antimicrobial, and wholly made from bamboo fiber unless they could be backed up with reliable evidence. (Bamboosa's site still had green claims when I checked, though.)

Are there actually any green bamboo fabrics? An FTC advisory to consumers says not if they feel soft: "They are made using toxic chemicals in a process that releases pollutants into the air. Extracting bamboo fibers is expensive and time-consuming, and textiles made just from bamboo fiber don't feel silky smooth."

What about all those wonderful antibacterial, breathable properties bamboo fabric was said to have? Greenwashing. "Even when bamboo is the 'plant source' used to create rayon, no traits of the original plant are left in the finished product," the FTC reported. I'll won't repeat the "we've been bamboozled" cliché. But it gives me a good idea for a t-shirt.

Photo: Handspun bamboo thread that has been carbonized for color. Credit: Heather Kennedy.

Engineering an Earth Airbag

October 07, 2009

If global warming causes all hell to break loose on our home planet, I'd feel better knowing humanity has a plan. A new geoengineering institute in the United Kingdom could help figure out one that doesn't give us all the willies.

The Oxford Geoengineering Institute recently launched with a board of eminent academia and industry folks, including knighted scientist David King. Director Tim Kruger founded Cquestrate, an open-source project looking at adding lime to the oceans to absorb carbon and reverse acidification. Shell is funding it, but this is no sinister plot. The project came out of an innovation competition and the company won't get any intellectual property. Kruger says scientists who studied the concept are preparing to publish in academic journals.

He's quick to clarify that the new institute will be looking at an array of ideas. "We need to start investigating whether we can produce an airbag for climate change," Kruger says. "You never really want to use an airbag, and if you do it’s a pretty uncomfortable experience, but it’s better than no airbag at all." And the institute isn't advocating geoengineering--just the need for a holistic, interdisciplinary evaluation that looks not just at the technical side but also ethics, social impact, governance, and economic feasibility.

"People are scared of geoengineering, and rightly so," Kruger told me, pointing out that this is why we need rigorous and clear-headed evaluations. As freaky as Earth-scale action sounds, I'll sleep better at night if we have an airbag.

Image: Compilation of Earth images. Credit: The Living Earth.

GET MORE OF THE WIDE ANGLE
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Superscanner is Superfast and Superfriendly

October 02, 2009

About a month ago, the University of Nottingham got the world's most advanced CT scanner with X-ray and 3-D imaging capabilities. Since then, scientists there have been loading all kinds of things into the machine.

Sacha Mooney, an associate professor in soil physics at the 
University of Nottingham, engaged an interdisciplinary group at the university to get the Nanotom scanner made by General Electric's Sensing and Inspection Technologies. I wondered why this was such a big deal. Can't you just put soil and other materials in a hospital scanner?

Mooney says that's exactly what he used to do earlier in his career, when the local hospital let him scan soil after hours. But the resolution wasn't high enough to see microstructures. Meanwhile, high-res scanners require small samples, meaning the materials have to be cut apart first. Larger-scale 3-D scanners exist but can take hours per scan, Mooney says. The Nanotom can do the two-stage scanning process in mere minutes.

The photobooth-sized scanner has enough space to accommodate a sample up to about the size of a one-liter bottle. Mooney says that one of the chaps from the Built Environment school is planning to scan sustainable materials to find out how well they perform, including heat retention.

The scanner can also illuminate how different soils and seeds bred to be drought-resistant interact. "We can actually see the water inside the plant," Mooney says. "We can almost watch roots growing in the soil."

The scientists are even working with a chocolate company that's interested in what causes their product to shrink and crack. Soil is great and all, but if you ask me what merits a superscanner, it's definitely chocolate science.

Images: The scanner shows a worm's eye view of a root (top) and the inside of a candy bar (bottom). Courtesy of Sacha Mooney.

Wide Angle: Arming Soybeans Against Pests

September 28, 2009

To a soybean plant, an aphid is a lot like a mosquito. What if we could help soybean plants fight back...and win? Scientists in Iowa might have found a way that doesn't involve pesticides.

W. Allen Miller, a professor of plant pathology at Iowa State University, and his colleague, entomology professor Bryony Bonning, have been studying a plant virus that aphids eat but just passes through them. The scientists are working on adding a gene to soybeans with the protein coat from the virus attached to an aphid toxin, so that when aphids feed on the plant, they die. The gene wouldn't affect humans.

"Something else could feed on the plant and they would not be targeted by this," Miller says. "It would be a very specific resistance approach." The scientists have preliminary data but need to do more control experiments to prove that their technique works.

In Iowa, soybean crops lost to aphids could top $250 million if nothing is done, according to research from the university. Iowa's soybean growers already shell out more than $65 million annually for pesticides, which can also kill aphids' natural predators.

"The last few years there have been crop dusters flying around," Miller says. "The only reason is the soybean aphids. If you had plants that are resistant, you wouldn’t have to do this."

Photo: Beyond bug spray--Students get swarmed with soybean aphids on the ISU campus. Credit: Logan Gaedke for Iowa State Daily.

GET MORE OF THE WIDE ANGLE
It's all about the genes:

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HowStuffWorks: Can Genetically Modified Mosquitoes Wipe Out Malaria?

Scientists, This Spud's For You

September 25, 2009

Potato fans can breathe a sigh of relief. An international team of scientists is closing in on the entire potato genome, helping to ensure that our crops will be safe long into the future.

Earlier this month scientists cracked the genome for the potato blight that caused the Irish Potato Famine. Now, the Potato Genome Sequencing Consortium has published a draft sequence covering 95 percent of the potato genome, a process that began in 2006. The potato genome is about a quarter the size of our human one.

This genome is especially helpful for potato breeders looking to identify traits such as drought tolerance and disease resistance. Michigan State University scientists were among the 39 consortium participants, and according to their site the typical American eats 119 pounds of potatoes annually. That sounds wrong, and yet so right. Maybe we've got potatoes in our genes.

Image: Mapping the DNA of tuber skin color. Credit: MPI for Plant Breeding Research.

Wide Angle: Engineering Law-Friendly Hemp

September 24, 2009

Plant biology professors at the University of Minnesota have identified which genes in Cannabis produce the drug part, a key discovery that could lead to legal hemp production in the United States.

Hemp and marijuana are two varieties of Cannabis--marijuana contains a lot of the drug tetrahydrocannabinol (THC) while hemp contains a small amount, but law enforcement has trouble telling them apart so all Cannabis is illegal stateside.

The university's David Marks and George Weiblen might have a solution. "THC is concentrated in these tiny hairs that cover the flowers of the plant," Weiblen says. "We did not know whether the drugs were produced in the hairs or elsewhere in the plant and transported. We now know that the drugs are produced in the hairs." Their discovery was recently published in the Journal of Experimental Botany.

Hemp is more durable than cotton and thrives in the Midwestern climate. Hemp farming flourished there until other fibers gained popularity and strict drug laws were passed. If the scientists can secure funding, the next step is to engineer a hairless hemp variety that law enforcement can quickly identify as drug-free. Or the U.S. could adopt legislation similar to Canada's, where hemp production is legal.

Here's a short video with more details on the research:

Photo: This is where the drugs come from. Credit: David Marks.

Nanopower Springs Into Battery Territory

September 22, 2009

It sounds like magic: teeny tiny little springs made from carbon could store as much energy as lithium ion batteries. New research out of MIT shows it's possible, at least according to the theoretical models.

Carol Livermore, an associate professor of mechanical engineering at the Institute, led research to show through mathematical modeling and testing that carbon molecules coaxed into tiny spring shapes have the potential to store exponentially more energy for their weight than springs made of steel. The work was published recently in Nanotechnology and the Journal of Micromechanics and Microengineering.

The next step will be to work on making an energy storage device by assembling longer, thicker nanotube fibers than the ones created for the tests. If the scientists can achieve that, they'll open the door to a compelling lithium-ion battery competitor. Carbon nanotubes are durable, so the springs could conceivably work in extreme temperatures that batteries can't handle. While this nano-spring power is still years away from a commercial introduction, I think it's worth the effort to develop. After all, good things tend to come in small packages.

Photo: Carole Livermore (left) with graduate student Frances Hill (right) in the MIT lab where all the magic happens. Credit: Patrick Gillooly.