Thursday, May 12, 2011

A new detection system can reveal bioterrorist attacks on our water supply network


If pathogens enter into our water supply network many people may fall ill quickly. To protect us against this biological threat, researchers have developed a detection system partly based on nanotechnology that can warn authorities in time.

In the 21st century several countries have suffered great losses after terrorist attacks. Although the risk of bioterrorist attacks or accidental contamination of our water supply network is low, the consequences could be fatal. Researchers connected to DINAMICS (DIagnostic NAnotech and MICrotech Sensors), a project co-funded by the European commission, have made a lab-on-a-chip device that can monitor our and spot different pathogens even at very low concentrations.

The device uses sensors with very small strands of different pathogenic integrated onto their surfaces to quickly recognize pathogenic DNA from water samples. The DNA in the sensors will only bind to the water samples’ corresponding DNA, multiplied for easier identification. To see what different DNAs are present in the water samples, the researchers apply a reaction called chemiluminescence that will make the bound DNAs emit light. The nanoscale reactions are then interpreted by a computer. The DINAMICS project’s researchers have also developed another type of sensor that changes the bound DNAs into electric signals. The signal’s magnitude is proportional to the quantity of pathogenic DNA from the water sample.

At present, water samples are brought to the laboratory for analysis. The researchers’ goal is to make this step redundant by bringing the laboratory to the water instead, since the device is part of a portable detection system. This would speed up the process substantially. If the system detects a biological threat the authorities can be informed through email or mobile phone.

Another way of spotting accidental or deliberate water contamination has been developed by the Fraunhofer Institute in Germany. By also recognizing that existing methods for water analysis are time-consuming they have set up a system called AquaBioTox, which uses living microorganisms. A sensitive camera system continuously records and analyses the microorganisms’ reactions to the water. Even though the researchers have documented a reliable and fast detection of contaminants, to guarantee robustness against false alarm and maximum reliability in diagnosis they recommend that the system is combined with other sensors on the market.

The DINAMICS project is planned to end the last day of March and if the system becomes widely available in the water industry this more cost-efficient way of testing could significantly improve safety, alone or in combination with other .

Provided by (news : web)

More effective and less risky when you paint the hull of your boat

Every boat owner recognises the dilemma: environmentally friendly or effective. Researchers at the University of Gothenburg have now found a way of reconciling these two almost unattainable aims. By using smart combinations of the most environmentally friendly biocides in the paint, it is possible to both reduce the total quantity of biocides and dramatically reduce the environmental impact.

"It's very easy to make an hull , and just as easy to make an effective hull paint. Yet there is still no paint that is both effective and environmentally friendly, which leaves both environmental authorities and boat owners dissatisfied," says Hans Blanck, Professor of Ecotoxicology at the Department of Plant and Environmental Sciences of the University of Gothenburg.

Professor Blanck has directed several sub-projects in the interdisciplinary research programme Marine Paint, which is financed by Mistra. Marine Paint is Sweden's largest combined research programme in the area of marine fouling and environmentally sound hull paints. The project began in 2003 with a substance that had been found to be effective against barnacles: medetomidine. Today the researchers are developing formulas to prevent all types of fouling through what are known as optimised blends of biocides, that is to say substances that can kill or otherwise cause problems for .

"The hull paints of today often contain one or two different biocides, and they need to be highly dosed to eliminate all types of fouling organisms. The idea behind optimised blends is to base them on several complementary biocides in the paint. In this way the combinations make more efficient use of each biocide and less overdosing is needed. We get rid of all fouling and the total need for biocides in the paint is reduced dramatically as a result."

To devise formulas for optimal blends, the researchers have developed a system of models in which the effect of different biocides on different types of fouling organisms is weighed up against the expected environmental risk. The result is a set of formulas – with different concentrations and combinations of biocides – that all are equally effective in preventing fouling. What distinguishes them is the anticipated risk to the environment. The formulas can therefore be adapted effectively to different conditions. The substances that the researchers have selected, in addition to medetomidine, are biocides that are on the market today and that will probably pass the ongoing evaluation under the EU Biocidal Products Directive.

Another common problem with present-day hull paints is that the active substances leach out too quickly. Large amounts of biocides are therefore needed for the paint to be effective over a long period.

"By using what are known as microcapsules, a microscopic bubble of polymer material containing dissolved bioicides, we can control release better. This technique works for virtually any biocide."

Provided by University of Gothenburg (news : web)

Chemist investigates material for next-generation computer memory

Investigating the building blocks for next-generation computer memory has earned a University of Houston (UH) chemist his third Tier One research award.

Vassiliy Lubchenko, an assistant professor of chemistry at UH, was recently selected as a 2011 Alfred P. Sloan Research Fellow for his achievements and potential to contribute substantially to his field. Drawn from 54 colleges and universities in the United States and Canada, this year's 118 fellows are early-career scientists and scholars. Lubchenko is one of four winners in Texas. Each will receive a $50,000 fellowship in support of original research and education in science, technology, engineering, mathematics and economic performance.

As a theoretical physical chemist, Lubchenko takes raw data from researchers in a lab and uses mathematical and computer modeling to explain existing measurements and predict what will occur in future experiments and other systems. Amorphous semiconductors, for example, are something he is studying for their applications in phase-change , which is a potential successor of .

"One can control the and of phase-change materials – and hence encode information – by varying the speed of cooling a melted material and forcing it to either crystallize or to form a glassy solid," Lubchenko said. "Glass transition is one of the most important, yet least understood, branches of modern physical chemistry. Semiconductor glasses exhibit many unique anomalies whose explanation has evaded researchers for decades. My findings show these anomalies are not a generic consequence of disorder, but instead can be traced to how these solids form from the corresponding liquid."

An important component of his research is to predict the structure and glass-forming ability of specific substances. This task is inaccessible to computer technology, but Lubchenko's technique applies a combination of analytical theories and computational modeling that singles out the most important aspects of the liquid dynamics and electronic motions that precede the glass transition and are amenable to mathematical treatment.

Another area of Lubchenko's research involves protein aggregation, a process thought to be responsible for many degenerative diseases, such as sickle cell anemia or Alzheimer's. His work may make it easier to make protein crystals, which could help in the treatment of such diseases.

"Vas' Sloan award, his third Tier One award since 2008, is recognition by his peers that he tackles and solves tough research problems," said David Hoffman, professor and chair of the chemistry department in the College of Natural Sciences and Mathematics at UH. "We are very proud of his accomplishments and feel fortunate to have him as a colleague."

Provided by University of Houston (news : web)

Airborne pollutants: New view of how water and sulfur dioxide mix

 High in the sky, water in clouds can act as a temptress to lure airborne pollutants such as sulfur dioxide into reactive aqueous particulates. Although this behavior is not incorporated into today's climate-modeling scenarios, emerging research from the University of Oregon provides evidence that it should be.

The role of sulfur dioxide -- a pollutant of volcanic gasses and many combustion processes -- in acid rain is well known, but how sulfur dioxide reacts at the surface of aqueous particulates in the atmosphere to form acid rain is far from understood.

In National Science Foundation-funded laboratory experiments at the UO, chemistry doctoral student Stephanie T. Ota examined the behavior of sulfur dioxide as it approaches and adsorbs onto water at low temperatures that mimic high-atmospheric conditions. Using a combination of short-pulsed infrared and visible laser beams, she monitored the interaction of sulfur dioxide with water as it is flowed over a water surface.

The results -- detailed online ahead of regular publication in the Journal of the American Chemical Society -- show that as sulfur dioxide molecules approach the surface of water, they are captured by the top-most surface water molecules, an effect that is enhanced at cold temperatures.

Although this reaching out, says co-author Geraldine L. Richmond, professor of chemistry, provides a doorway for sulfur dioxide to enter the water solution, the weak nature of the surface-bonding interaction doesn't guarantee that the water temptress will be successful.

"We have found that that the sulfur dioxide bonding to the surface is highly reversible and does not necessarily provide the open doorway that might be expected," Ota said. "For example, for highly acidic water, the sulfur dioxide approaches and bonds to the water surface but shows little interest in going any further into the bulk water."

The uptake of gases like sulfur dioxide has important implications in understanding airborne pollutants and their role in global warming and climate change. Sulfur dioxide that has come together with water, becoming aqueous, reflects light coming toward the planet, while carbon dioxide accumulating in the atmosphere traps heat onto the planet.

Understanding the interaction of surface water molecules, such as those in clouds and fog, with pollutants rising from human activity below may help scientists better predict potential chemical reactions occurring in the atmosphere and their impacts, said Richmond, who was elected May 3 as a member of the National Academy of Sciences.

"In the past we presumed that most chemistry in the atmosphere occurred when gas molecules collide and react," she said. "These studies are some of the first to provide molecular insights into what happens when an atmospherically important gas such as sulfur dioxide collides with a water surface, and the role that water plays in playing the temptress to foster reactivity."

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Oregon.

Journal Reference:

Stephanie T. Ota, Geraldine L. Richmond. Chilling Out: A Cool Aqueous Environment Promotes the Formation of Gas–Surface Complexes. Journal of the American Chemical Society, 2011; : 110426082204049 DOI: 10.1021/ja201027k

Methane levels 17 times higher in water wells near hydrofracking sites, study finds

A study by Duke University researchers has found high levels of leaked methane in well water collected near shale-gas drilling and hydrofracking sites. The scientists collected and analyzed water samples from 68 private groundwater wells across five counties in northeastern Pennsylvania and New York.

"At least some of the homeowners who claim that their wells were contaminated by shale-gas extraction appear to be right," says Robert B. Jackson, Nicholas Professor of Global Environmental Change and director of Duke's Center on Global Change.

Hydraulic fracturing, also called hydrofracking or fracking, involves pumping water, sand and chemicals deep underground into horizontal gas wells at high pressure to crack open hydrocarbon-rich shale and extract natural gas.

The study found no evidence of contamination from chemical-laden fracking fluids, which are injected into gas wells to help break up shale deposits, or from "produced water," wastewater that is extracted back out of the wells after the shale has been fractured.

The peer-reviewed study of well-water contamination from shale-gas drilling and hydrofracking appears this week in the online Early Edition of the Proceedings of the National Academy of Sciences.

"We found measurable amounts of methane in 85 percent of the samples, but levels were 17 times higher on average in wells located within a kilometer of active hydrofracking sites," says Stephen Osborn, postdoctoral research associate at Duke's Nicholas School of the Environment. The contamination was observed primarily in Bradford and Susquehanna counties in Pennsylvania.

Water wells farther from the gas wells contained lower levels of methane and had a different isotopic fingerprint.

"Methane is CH4. By using carbon and hydrogen isotope tracers we could distinguish between thermogenic methane, which is formed at high temperatures deep underground and is captured in gas wells during hydrofracking, and biogenic methane, which is produced at shallower depths and lower temperatures," says Avner Vengosh, professor of geochemistry and water quality. Biogenic methane is not associated with hydrofracking.

"Methane in water wells within a kilometer had an isotopic composition similar to thermogenic methane," Vengosh says. "Outside this active zone, it was mostly a mixture of the two."

The scientists confirmed their finding by comparing the dissolved gas chemistry of water samples to the gas chemistry profiles of shale-gas wells in the region, using data from the Pennsylvania Department of Environmental Protection. "Deep gas has a distinctive chemical signature in its isotopes," Jackson says. "When we compared the dissolved gas chemistry in well water to methane from local gas wells, the signatures matched."

Methane is flammable and poses a risk of explosion. In very high concentrations, it can cause asphyxiation. Little research has been conducted on the health effects of drinking methane-contaminated water and methane isn't regulated as a contaminant in public water systems under the EPA's National Primary Drinking Water Regulations.

The Duke team collected samples from counties overlying the Marcellus shale formation. Accelerated gas drilling and hydrofracking in the region in recent years has fueled concerns about well-water contamination by methane, produced water and fracking fluids, which contain a proprietary mix of chemicals that companies often don't disclose.

Shale gas comprises about 15 percent of natural gas produced in the United States today. The Energy Information Administration estimates it will make up almost half of the nation's production by 2035.

The study was funded by the Nicholas School and Duke's Center on Global Change. Nathaniel R. Warner, a PhD student of Vengosh's, was a co-author.

Independent of the PNAS study, Jackson and colleagues at the Center for Global Change, the Nicholas School and Duke's Nicholas Institute for Environmental Policy Solutions have issued a white paper on hydrofracking at It includes recommendations for monitoring and addressing potential environmental and human health risks.

Story Source:

The above story is reprinted (with editorial adaptations ) from materials provided by Duke University, via EurekAlert!, a service of AAAS.

Journal Reference:

Stephen G. Osborn, Avner Vengosh, Nathaniel R. Warner, Robert B. Jackson. Methane contamination of drinking water accompanying gas-well drilling and hydraulic fracturing. Proceedings of the National Academy of Sciences, 2011; DOI: 10.1073/pnas.1100682108

Yeast Alive! Watch Yeast Live and Breathe


Have you ever looked closely at a piece of sandwich bread—really closely? Notice all of those tiny holes? They probably got there thanks to tiny living organisms called yeast. Even though these organisms are too small to see with the naked eye (each granule is a clump of single-celled yeasts), they are indeed alive just like plants, animals, insects and humans. In fact, we have some interesting things in common with these little creatures!

When you breathe out, part of what you are exhaling is a gas known as carbon dioxide. Yeast also releases carbon dioxide when it is active (although it's way too small and simple an organism to have lungs). Yeast are so small you can't see individual ones very well. So how can you tell if they are alive or not? You can enlist a whole bunch of them to blow up a balloon for you!

When you buy a packet of baker's yeast at the store, the organisms inside are in a state of inactivity so they don't need to eat (keeping them cool and dry helps keep them preserved this way). But when you mix them into dough, they wake up and begin eating—and making carbon dioxide.

When you make yeast-based bread, you often have to wait for it to rise. During this step the dough might appear to be growing. But what is really happening is that you're giving the tiny yeast organisms time to eat and create small pockets of carbon dioxide inside the dough, which is what makes the dough seem to grow larger—and which leads to fluffy bread! (Bread products that don't have yeast rise during baking thanks to other ingredients, such as baking powder.)

Why do the yeast organisms "wake up" when you put them into a dough mixture? Like other living organisms, they need food and water. So by putting them in a moist environment with nutrients (such as sugar), they become "active."

•    Fresh packet of baker's yeast (check the expiration date)
•    Tablespoon of sugar
•    Clear plastic bottle with a small opening (such as a water bottle)
•    Funnel
•    Small balloon
•    Warm water

Preparation •    Carefully stretch out the balloon by blowing it up a few times (might as well give the tiny yeast a hand!).
•    Pour an inch or two of warm water into the clear plastic bottle.

•    Pour the packet of yeast into the bottle and swirl it around.
•    Now add the sugar, and swirl the mixture around a little bit more.
•    Stretch the balloon opening over the top of the plastic bottle.
•    Look through the bottle—do you see any signs of life?
•    Leave the balloon-covered, yeast-filled bottle in a warm place for 15 or 20 minutes.
•    Any signs of life? Do you see any changes in the balloon?
•    Will the yeast keep making more and more carbon dioxide? Why might it stop?
•    Extra: If you have more yeast, try making a loaf of bread from scratch. You can find simple recipes—with the science behind them—on the Exploratorium's "Science of Cooking" website.

[To get the full effect for the time-lapse section in our video we used three tablespoons of yeast, three tablespoons of sugar, and we allowed the mixture to sit for 40 minutes.]

Read on for observations, results and more resources.


Whales Return to NYC Harbor

[audio of blue whale song] That's the song of the blue whale, the largest animal on the planet. It's been sped up 30 times faster so that our ears can hear it. In reality, these infrasound songs were captured in 2009, off the coast of… Long Island?

That's right. Whales are back in the Big Apple. Endangered fin whales sing near the Verrazano Narrows while slightly farther out to sea humpback, right and the big blue whales call to each other. In fact, at least six species of baleen whales have been detected singing in the region.

Perhaps this isn't so surprising given that in the early 1800s some Long Island towns made their living from killing whales just offshore. But such whaling, paired with high seas expeditions, brought many whales to the brink of extinction.

In more recent decades, much whaling has been stopped, except for a few holdout nations, such as Japan and Norway. The end of the slaughter means the return of the whales, including intrepid individuals venturing back to their former homes just offshore from one of the largest urban areas in the world, full of noisy shipping.

Monitoring the whales' songs might help reveal some of what attracts them to the region, say scientists at the Cornell University Bioacoustics Research Program. But I think it's obvious. They want to sing on Broadway.