Scientists develop material to remove radioactive contaminants from drinking water

A combination of forest byproducts and crustacean shells may be the key to removing radioactive materials from drinking water, researchers from North Carolina State University have found.

"As we're currently seeing in Japan, one of the major health risks posed by nuclear accidents is radioactive iodide that dissolves into drinking water. Because it is chemically identical to non-radioactive iodide, the human body cannot distinguish it – which is what allows it to accumulate in the thyroid and eventually lead to cancer," says Dr. Joel Pawlak, associate professor of forest biomaterials. "The material that we've developed binds iodide in water and traps it, which can then be properly disposed of without risk to humans or the environment."

The new material - a combination of hemicellulose, a byproduct of forest materials, and chitosan, crustacean shells that have been crushed into a powder - not only absorbs water, but can actually extract contaminates, such as radioactive iodide, from the water itself. This material, which forms a solid foam, has applications beyond radioactive materials. Pawlak and fellow researchers found that it has the ability to remove heavy metals – such as arsenic – from water or salt from sea water to make clean drinking water.

"In disaster situations with limited-to-no power source, desalinating drinking water is difficult, if not impossible. This foam could be brought along in such situations to clean the water without the need for electricity," Pawlak says. "This material could completely change the way we safeguard the world's drinking water supply."

The foam, which is coated on wood fibers, is used like a sponge that is immersed in water. For smaller-scale applications, the foam could be used in something like a tea bag. Or on a larger scale, water could be poured through it like a filter.

Provided by North Carolina State University (news : web)

Student creates clothes that trap harmful gases

 A new Cornell cloth that can selectively trap noxious gases and odors has been fashioned by a senior into a mask and hooded shirts inspired by the military.

The garments use metal organic framework molecules (MOFs) and cellulose fibers that were assembled in assistant fiber science professor Juan Hinestroza's lab to create the special cloth.

MOFs, which are clustered crystalline compounds, can be manipulated at the nanolevel to have cages that are the exact same size as the gas they are trying to capture, said Jennifer Keane '11, a fiber science and apparel design (FSAD) major in the College of Human Ecology.

Keane worked with Hinestroza and fiber science postdoctoral associate Marcia Da Silva Pinto to create the gas-absorbing hood and mask. Some of the basic science behind this project was funded by the U.S. Department of Defense.

"The initial goal of attaching the MOFs to fibers was sponsored by the Defense Threat Reduction Agency. We wanted to harness the power of these molecules to absorb gases and incorporate these MOFs into fibers, which allows us to make very efficient filtration systems," Hinestroza said.

Da Silva Pinto first created MOF fabrics in Hinestroza's lab, working in collaboration with chemists from Professor Omar Yaghi's group at the University of California-Los Angeles; Yaghi is one of the pioneers and leaders of MOF chemistry, said Hinestroza.

At first the process did not work smoothly. "These crystalline molecules are like a powder that cannot easily become part of cloth," Da Silva Pinto noted. After months of trying to attach the particles to the fiber, the researchers realized that, "The key was to bring the fiber to the particle ... It was a real paradigm shift," she said.

"Now we can make large surfaces of fabric coated with MOFs, and we are looking at scaling up this technology to nanofibers," said Hinestroza. "This type of work would only be possible at a place like Cornell where you have this unique merging of disciplines, where a fashion designer can interact easily with a chemist or a materials scientist."

Though trained as a chemical engineer, Hinestroza said he likes "to work with designers because they think very differently than scientists. I love that because that's where the real creativity comes, when you have this collision of styles and thinking processes."

Keane, who took Hinestroza's Textiles, Apparel and Innovation class, said she started Cornell as a pre-med major but switched to FSAD because she enjoyed the creative aspect of sewing and designing her own clothing in high school. She has since interned with Nike and recently received a job offer from Adidas.

She noted that while her MOF hood and mask will not be showcased in the upcoming Cornell Fashion Collective spring fashion show at Barton Hall, April 16, 7-9:30 p.m., her line of comfortable women's sportswear will be. It includes many geometric patterns and bright jewel tones.

"It's a lot of knits, jersey and this brushed denim, which is really soft ... It was based off of jewelry designs that I saw in Italy," she said.

Provided by Cornell University (news : web)

Injectable gel could spell relief for arthritis sufferers

Some 25 million people in the United States alone suffer from rheumatoid arthritis or its cousin osteoarthritis, diseases characterized by often debilitating pain in the joints. Now researchers at Brigham and Women's Hospital (BWH) report an injectable gel that could spell the future for treating these diseases and others.

Among its advantages, the gel could allow the targeted release of medicine at an affected joint, and could dispense that medicine on demand in response to enzymes associated with arthritic flare-ups.

"We think that this platform could be useful for multiple medical applications including the localized treatment of cancer, ocular disease, and cardiovascular disease," said Jeffrey Karp, leader of the research and co-director of the Center for Regenerative Therapeutics at BWH.

Karp will present the findings April 15 at the annual meeting of the Society for Biomaterials (SFB) as part of winning the coveted SFB Young Investigator Award for this work. The work was also reported by Karp and colleagues in the May 2011 issue of the Journal of Biomedical Materials Research (JBMR): Part A, and is currently available on the journal's website.

Local Delivery

Arthritis is a good example of a disease that attacks specific parts of the body. Conventional treatments for it, however, largely involve drugs taken orally. Not only do these take a while (often weeks) to exert their effects, they can have additional side effects. That is because the drug is dispersed throughout the body, not just at the affected joint. Further, high concentrations of the drug are necessary to deliver enough to the affected joint, which runs the risk of toxicity.

"There are many instances where we would like to deliver drugs to a specific location, but it's very challenging to do so without encountering major barriers," says Karp, who also holds appointments through Harvard Medical School (HMS), Harvard Stem Cell Institute (HSCI), and the Harvard-MIT Division of Health Sciences and Technology (HST).

For example, you could inject a drug into the target area, but it won't last long--only minutes to hours--because it is removed by the body's highly efficient lymphatic system. What about implantable drug-delivery devices? Most of these are composed of stiff materials that in a dynamic environment like a joint can rub and cause inflammation on their own. Further, most of these devices release medicine continuously--even when it's not needed. Arthritis, for example, occurs in cycles characterized by flare-ups then remission.

Toward the Holy Grail

"The Holy Grail of drug delivery is an autonomous system that [meters] the amount of drug released in response to a biological stimulus, ensuring that the drug is released only when needed at a therapeutically relevant concentration," Karp and colleagues write in JBMR. His coauthors are Praveen Kumar Vemula, Nathaniel Campbell, and Abdullah Syed of BWH, HMS and HSCI; Eric Boilard (now at Université Laval), Melaku Muluneh, and David Weitz of Harvard University; and David Lee of BWH, currently at Novartis. Karp notes the key involvement of Lee, a doctor who is "treating patients with the problem we're trying to solve."

The researchers tackled the problem by first determining the key criteria for a successful locally administered arthritis treatment. In addition to having the ability to release drug on demand, for example, the delivery vehicle should be injectable through a small needle and allow high concentrations of the drug. The team ultimately determined that an injectable gel seemed most promising.

Next step: what would the gel be made of? To cut the time involved in bringing a new technology to market, the team focused only on materials already designated by the Food and Drug Administration as being generally recognized as safe (GRAS) for use in humans.

Ultimately, they discovered a GRAS material that could be coaxed into self-assembling into a drug-containing gel. "The beauty of self-assembly is that whatever exists in solution during the assembly process--in this case, a drug--becomes entrapped," says Vemula, first author of the paper, who also has an appointment at HST.

They further expected that the same material would disassemble, releasing its drug payload, when exposed to the enzymes present during inflammations like those associated with arthritis.

Promising Results

A series of experiments confirmed this. For example, the team created a gel containing a dye as a stand-in for a drug, then exposed it to enzymes associated with arthritis. The drug was released. Further, the addition of agents that inhibited the enzymes stopped the release, indicating that the gel "can release encapsulated agents in an on-demand manner," the researchers write. Although the team has yet to test this in humans, they did find that dye was also released in response to synovial fluid taken from arthritic human joints.

Among other promising results, the researchers found that gel injected into the healthy joints of mice remained stable for at least two months. Further, the gel withstood wear and tear representative of conditions in a moving joint.

Additional tests in mice are underway. The technique has yet to be demonstrated in humans, but the researchers write that it "should have broad implications for the localized treatment of many…diseases" caused by the enzymatic destruction of tissues.

The researchers have applied for a patent on the work, which was sponsored by the Center for Integration of Medicine and Innovative Technology (CIMIT) through the U.S. Army and by the Harvard Catalyst Program.

Provided by Brigham and Women's Hospital

Keeping beer fresh longer

Researchers are reporting discovery of a scientific basis for extending the shelf life of beer so that it stays fresh and tastes good longer. For the first time, they identified the main substances that cause the bitter, harsh aftertaste of aged beer and suggest that preventing the formation of these substances could help extend its freshness. Their findings appear in ACS' Journal of Agricultural and Food Chemistry.

Thomas Hofmann and colleagues point out that beer can develop an unpleasant, bitter aftertaste as it ages. Unlike wine, scotch whiskey, and bourbon, beer tastes best when consumed fresh. Experts estimate that the average beer goes bad after 6 to 12 months of storage. Scientists have identified several dozens of the key bitter-tasting substances formed during beer manufacturing — mostly so-called "prenylated polyketides" derived from hops. Until now, however, nobody had solid information about the bitter substances that form as beer ages.

The scientists analyzed a variety of commercial beers both before and after storage. They identified 56 substances that contribute to beer's bitter taste, including five that appear to be largely responsible for its harsh flavor after aging. "The present study offers the scientific basis for a knowledge-based extension of the shelf life of the desirable beer's bitter taste and the delay of the onset of the less preferred harsh bitter aftertaste by controlling the initial pH value of the beer and by keeping the temperature as low as possible during storage of the final beverage," the study concludes.

Provided by American Chemical Society (news : web)

Award funds research on the mysteries of charged droplets

A UC Davis chemical engineer has won a five-year, $420,000 early career development award from the National Science Foundation to support research on electrical charges of fluid droplets.

William Ristenpart, an assistant professor who has appointments in both the UC Davis Department of Food Science and Technology and the Department of Chemical Engineering and Materials Science, uses high-speed video and a high-resolution electrochemical measuring technique known as “chronocoulometry” to answer fundamental questions about how droplets of various liquids acquire an electrical charge.

Findings from these studies are expected to have applications in a number of fields including petroleum and food-oil processing, and manufacture of microchips that are capable of performing multiple laboratory functions.

“The amount of charge obtained by metal spheres has been known since the time of Maxwell in the 1860s, but 150 years later, we still don’t understand charge transfer into liquid drops,” Ristenpart said. “I’m excited that this research will shed light on a fundamental problem with applications ranging from food science to atmospheric science.”

Ristenpart’s research team investigates the physical, chemical and biological phenomena of fluids, including fluid motion caused by electrical fields, how different food metabolites affect red blood cells, and the behavior of fluids at the microminiaturized scale.

Provided by UC Davis (news : web)

Hunting for deadly bacteria

You can't see them, or smell them or taste them. They can be in our water and in our food, multiplying so rapidly that conventional testing methods for detecting pathogens such as E.coli, salmonella and listeria come too late for the tens of thousands of Canadians who suffer the ill effects of these deadly bacteria.

Biochemist Yingfu Li and his research team have developed a simple test that can swiftly and accurately identify specific pathogens using a system that will 'hunt' for bacteria, identifying their harmful presence before they have a chance to contaminate our food and water.

Like any living thing, bacteria have their own spoor, leaving behind molecular trails of bacterial 'droppings'. Li tracks these metabolic by-products with molecular beacons - little lighthouses on a molecular scale that actually light up when they detect one of the by-products left behind.

Li created a DNAzyme sensor that will be able to identify any bacteria, utilizing a method that doesn't require the steps and specialized equipment typically used to identify whether or not harmful bacteria are present.

"Current methods of food-borne bacterial detection take time. The five days it takes to detect listeria, for example, can translate into an outbreak that costs lives. We have developed a universal test that uses less complex procedures but still generates precise and accurate results," said Li, a Canada Research Chair in Directed Evolution of Nucleic Acids.

Li's fluorescent test system was highlighted in Angewandte Chemie International Edition, a prestigious weekly chemistry journal that ranks among the best for the original research it publishes. Li's paper, co-authored with lab members Monsur Ali, Sergio Aguirre and Hadeer Lazim, was designated a 'hot paper' by Angewandte's editors for "its importance in a rapidly evolving field of current interest".

"McMaster researchers are known for their ability to provide solutions to problems that impact the public's well-being, said Mo Elbestawi, vice-president, research and international affairs at McMaster. "The test that Professor Li has developed will help safeguard the health of Canadians, and supply industry with a reliable means to bring safe food products to consumers and reduce their time to market."

Provided by McMaster University (news : web)

Eco-friendly treatment for blue jeans offers alternative to controversial 'sandblasting'

Blue denim jeans are one of the most popular and iconic fashion items in the world; now a study published in Biotechnology Journal reveals a cheaper, more efficient and eco-friendly method for treating dyed denim. The process of 'surface activation' used to wash-down the denim following dyeing could also offer an alternative to the dangerous, and internationally banned, sandblasting technique.

"The global production of denim is estimated at 3 billion linear meters and more than 4 billion garments per year," said Thomas Bechtold, from the Research Institute for Textile Chemistry and Textile Physics at the University of Innsbruck. "To create blue jeans denim is dyed with indigo an organic compound which is estimated to be produced in quantities of over 30.000 tons per year."

Controversially a process of sandblasting is often used for some jeans which are styled with a worn or torn look. The technique is banned in many countries as it can lead to lung disease; however, it is still used in denim workshops in Bangladesh, Egypt, China, Turkey, Brazil and Mexico. Many of the jeans sold in Europe are produced in these countries.

Dr Bechtold and his team focused their research on alternative treatment processes, studying the use of chemicals used to bleach the denim.

"A central step in the processing of indigo dyed textiles such as blue jeans are the wash and bleach processes used to create a final wash down effect," said Bechtold. "To remove the ring dyed indigo dyestuff manufactures use a combination of drum washing machines and chemical treatments."

Oxidising agents are an essential part of this bleach process, with chemicals such as Sodium Hypochlorite (NaOCl) used to reduce the amount of dyestuff. Due to its low cost and the broad amount of bleach effects it can produce NaOCl is currently used in 80% of jean production.

Because indigo dyeing is concentrated on the outer layers of fabric Dr Bechtold's team turned to a surface activation technique Because indigo dyeing is concentrated on the outer layers of fabric Dr Bechtold's team turned to a surface activation technique which could lead to a reduction in the amount of chemicals needed to achieve the same effect. .

The surface activation technique presents several advantages including preventing the decease of fabric strength, shortening the duration of the wash-down process and reducing the concentrations of costly chemicals.

"This method also offers a replacement of the sandblasting of denim, which is an extremely unhealthy process for which, until now, there have been few alternatives available", concluded Bechtold. "The surface activation method also allows for more eco-friendly processing of jeans in the garment industry which is approximately 10% of the total cotton market worldwide."

Provided by Wiley (news : web)