Researchers expand capabilities of miniature analyzer for complex samples

It’s not often that someone can claim that going from a positive to a negative is a step forward, but that’s the case for a team of scientists from the National Institute of Standards and Technology (NIST) and private industry. In a recent paper,* the group significantly extended the reach of their novel microfluidic system for analyzing the chemical components of complex samples. The new work shows how the system, meant to analyze real-world, crude mixtures such as dirt or whole blood, can work for negatively charged components as well as it has in the past for positively charged ones.

In previous work,** NIST researchers Elizabeth Strychalski and David Ross, in collaboration with Alyssa Henry of Applied Research Associates Inc. (Alexandria, Va.), demonstrated the use of a technique called GEMBE (for “gradient elution moving boundary electrophoresis”) for analyzing complex samples. The NIST-developed system combines a simple microfluidic structure (two reservoirs connected by a microchannel), electrophoresis (which uses electricity to move sample components through a fluid) and pressure-driven flow.

Analyzing complex samples can be difficult because components in these samples (such as the fat globules in milk or proteins in blood) can “foul” or contaminate microfluidic channels. The traditional solution has been to remove contaminants with costly, time-consuming sample preparation prior to analysis.

GEMBE solves this problem by pumping fluid through the microchannel using a controlled pressure in the direction opposite to electrophoresis. This opposing pressure-driven flow acts as a "fluid gate" between the sample reservoir and the microchannel. Gradually reducing the pressure of the counterflow opens the "gate" a little bit at a time. A specific sample component is detected when the pressure flow becomes weak enough—i.e. the "gate" opens wide enough—that the component’s electrophoretic motion pushes it against the pressure-driven flow and into the channel for detection. In this way, different components enter the channel at different times, based on their particular electrophoretic motion. Most importantly, the channel doesn’t become fouled because the unwanted components in the sample are held out.

“Previously, we validated the GEMBE technique by quantitatively analyzing components from complex samples in solution that were cationic [positively charged] and could, therefore, be separated relatively easily from anionic [negatively charged] contaminants in a mixture,” Strychalski says. “However, we needed a way to make GEMBE work when both the desired components and the contaminants are negatively charged.”

For some samples, Strychalski says, this was achieved by choosing a different solution pH to change the electrophoretic motion of the unwanted components. In other cases, the addition of commercially available surface coatings to the sample did the trick without compromising the ease and robustness of the GEMBE technique.

“Additives can be selected that will interact with material in the sample that we don’t want to study,” Strychalski explains. “If we choose the right coating, it will slow the electrophoretic motion of contaminants relative to the desired components. This prevents the former from interfering with analysis while still allowing the latter to enter the microchannel for detection.”

Strychalski and her colleagues plan to continue refining the GEMBE system, including an effort to define which surface coatings optimize the technique for specific components in a variety of complex samples.

More information: E.A. Strychalski, et al. Expanding the capabilities of microfluidic gradient elution moving boundary electrophoresis for complex systems. Analytical Chemistry, Vol. 83, No. 16, pp 6316–6322. Aug. 15, 2011.

See “‘No Muss, No Fuss’ Miniaturized Analysis for Complex Samples Developed” http://www.physorg … 7763391.html

Provided by National Institute of Standards and Technology (news : web)

Panda poop may be a treasure trove of microbes for making biofuels

 

Panda poop contains bacteria with potent effects in breaking down plant material in the way needed to tap biomass as a major new source of “biofuels” produced not from corn and other food sources, but from grass, wood chips and crop wastes, scientists reported today at the 242nd National Meeting & Exposition of the American Chemical Society (ACS).

“Who would have guessed that ‘panda poop’ might help solve one of the major hurdles to producing biofuels, which is optimizing the breakdown of the raw plant materials used to make the fuels?” said study co-author Ashli Brown, Ph.D. “We hope our research will help expand the use of biofuels in the future and help cut dependency on foreign oil. We also hope it will reinforce the importance of wildlife conservation.”

Brown pointed out that bacteria from the giant panda are particularly promising for breaking down the super-tough plant material known as lignocellulose in switch grass, corn stalks and wood chips. That advance could speed the development of so-called cellulosic biofuels made from these tough plant materials in a way that doesn’t rely on precious food crops such as corn, soybeans and sugar now used for making biofuels, she noted.

Scientists have long known that giant pandas — like termites and cattle — have bacteria in their digestive systems to break down the cellulose in plants into nutrients. Bamboo constitutes about 99 percent of the giant panda’s diet in the wild. An adult may eat 20-40 pounds of bamboo daily — leaves stems, shoots and all. Until the energy crunch fostered interest in biofuels, however, scientists never thought to parse out exactly what microbes in the giant panda gastrointestinal system were involved in digestion.

Brown and colleagues, including graduate student Candace Williams, collected and analyzed the fresh feces of a pair of male and female pandas at the Memphis Zoo for over a year. They identified several types of digestive bacteria in the panda feces, including some that are similar to those found in termites, which are renowned for their ability to digest wood.

“Our studies suggest that bacteria species in the panda intestine may be more efficient at breaking down plant materials than termite bacteria and may do so in a way that is better for biofuel manufacturing purposes,” said Brown, who is with Mississippi State University.

Based on other studies, Brown estimated that under certain conditions these panda gut bacteria can convert about 95 percent of plant biomass into simple sugars. The bacteria contain enzymes — highly active substances that speed up chemical reactions — so powerful that they can eliminate the need for high heat, harsh acids and high pressures currently used in biofuel production processes, she said. Those processes also tend to be time- and energy-intensive, as well as expensive. Panda bacteria could therefore provide a faster, cleaner and less costly way to make biofuels.

Brown is currently trying to identify every intestinal bacterium in the giant panda in order to isolate the most powerful digestive enzymes for biofuel production and other purposes. She noted that scientists could use well-established genetic engineering technology to put the genes that produce those enzymes into yeasts. The yeasts then would produce the enzymes and could be grown on a commercial scale to provide large amounts of enzymes for a biofuel industry.

“The discovery also teaches a lesson about the importance of biodiversity and preserving endangered animals,” Brown said, noting that less than 2,500 giant pandas remain in the wild and about 200 are in captivity. “Animals and plants are a major source of medicines and other products that people depend on. When we lose them to extinction, we may lose potential sources of these products.”

The U.S. Department of Energy, The Memphis Zoological Society, the Mississippi Corn Promotion Board, and the Southeastern Research Center at Mississippi State provided funding for this study.

Provided by American Chemical Society (news : web)

UD chemist investigates reactions that damage paintings

In the days before artists could go to a store and buy commercial paints, they mixed their own, often combining pigments made of lead salts with such materials as egg whites and vegetable oils.

"They were seat-of-the-pants chemists," says Cecil Dybowski, professor of chemistry and biochemistry at the University of Delaware. "But they didn't understand the chemistry itself, and they didn't foresee what would happen to those pigments in the future as the paintings got older."

What generally happened is that internal chemical reactions gradually occurred in the dried paints, causing them to change in various ways and eventually damaging their works of art, no matter how carefully those paintings had been cared for over the years. 

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Credit: Andrea Boyle

Now, supported by a National Science Foundation (NSF) grant, Dybowski and colleagues at New York's Metropolitan Museum of Art will create models of centuries-old paints and use special spectroscopic techniques to analyze the reactions that occur within them. Researchers at the Metropolitan came up with the idea for the project and contacted Dybowski because of his laboratory's international reputation in spectrometry and his own research focus on lead.

Specifically, Dybowski and other UD scientists use nuclear magnetic resonance (NMR) spectrometry, a powerful technique for analyzing a variety of materials ranging from natural substances to synthetic molecules to biological systems. NMR analysis provides detailed information about a material's structure, composition and dynamics. 

Last year, a team of researchers in the Department of Chemistry and Biochemistry, including Dybowski, received a $2.2 million grant to acquire a highly specialized NMR spectrometer that will be used by scientists throughout the University and the region.

"This project builds on the expertise that we have here and that the Met has there, so it's very collaborative," Dybowski says. "I wouldn't be able to attack this problem on my own, and I don't think the Met could either. The NSF likes collaborative projects like this, which looks at art as science and science as art."

The chemical makeup of paints and pigments has been studied extensively over the years in art conservation work, but this project seeks to duplicate the chemistry of the old paints and then analyze those chemical reactions with the most modern technology. NMR can't yet easily study the surface of a painting, and the analysis requires a relatively large sample, which is why the researchers will be creating their own paints to use as models.

"We can't remove large samples of paint from works of art without damaging the paintings, so we'll use these models to study the internal chemistry," Dybowski says. The team's plans call for a shared postdoctoral researcher to prepare materials at the Met—using the known chemical makeup of old paints and then subjecting them to an accelerated aging process—and then bring them to UD for NMR analysis. 

The three-year project will begin in September. The Metropolitan's researchers are Silvia Centeno, a physical chemist who specializes in a type of analysis known as Raman spectroscopy, and Nicholas Zumbulyadis, a retired NMR spectroscopist from the Eastman Kodak Research Laboratories who is also a consulting expert on the chemistry of paints and glazes. 

"I never set out to study artworks," Dybowski says. "I was interested in the fundamental spectroscopic properties of lead, and I've been studying that for about 10 years. Then, out of the blue, I got the call from the Met. I think it shows the amazing diversity of chemistry and how knowledge that might seem theoretical suddenly becomes extremely pertinent to problems one might not have envisioned."

Provided by University of Delaware (news : web)

A step toward a saliva test for cancer

A new saliva test can measure the amount of potential carcinogens stuck to a person's DNA -- interfering with the action of genes involved in health and disease -- and could lead to a commercial test to help determine risks for cancer and other diseases, scientists reported here today during the 242nd National Meeting & Exposition of the American Chemical Society (ACS).

"The test measures the amount of damaged DNA in a person's body," said Professor Hauh-Jyun Candy Chen, Ph.D., who led the research team. "This is very important because such damaged DNA — we call this 'DNA adducts' — is a biomarker that may help doctors diagnose diseases, monitor how effective a treatment is and also recommend things high-risk patients can do to reduce the chances of actually getting a disease," said Chen. The research team is at National Chung Cheng University (NCCU) in Taiwan. "We tried urine and blood and found these adducts. Then we turned our attention to saliva. It's much more convenient to collect a sample of saliva."

A DNA adduct forms when a potentially cancer-causing substance is chemically attached to a strand of DNA, which makes up genes. People come into contact with such substances in the environment, certain workplaces and through everyday activities. Cigarette smoke, for instance, contains at least 20 known cancer-causing substances. When such a substance binds to DNA, it changes the DNA so that genes may not work normally. Our body has a built-in repair system that can naturally clear up such damage. If that system fails, however, a DNA adduct could lead to mutations or genetic changes that, in turn, could lead to cancer. DNA adducts also accumulate with aging and have been linked to other health problems, including inflammatory diseases and chronic brain disorders like Alzheimer's disease.

The new test measures the levels of five key DNA adducts, including some that form as a result of cigarette smoking. Traditionally, DNA for such tests had to be obtained by taking a blood sample and processing the white blood cells, which contain large amounts of the genetic material. More recently, however, scientists found that DNA samples could be obtained more conveniently from saliva. The DNA is present in white blood cells found naturally in saliva and from cells shed from the lining of the mouth. Chen uses a very sensitive laboratory instrument called a mass spectrometer to analyze for DNA adducts.

Chen envisions several uses for any potential commercial version of the test, which she said would probably cost several hundred dollars. One, for example, might be health promotion among people exposed to carcinogens due to lifestyle, occupation or other factors. Detection of high levels of DNA adducts in cigarette smokers, for instance, could encourage them to stop. Follow-up tests showing a decline in DNA adducts could reinforce their healthier lifestyle.

Provided by American Chemical Society (news : web)

BASF invests in structural infrastructure at the Ludwigshafen Site

“We are constantly developing the Ludwigshafen site further so that it is always state-of-the-art and remains successful in international competition. In addition to investments in production, this involves modernization and targeted development of the structural infrastructure,” said Dr. Bernhard Nick, Site Manager of the BASF SE Ludwigshafen Verbund site. “In the process, we are using solutions that fit the style of BASF by bringing together the time-tested with the modern. We are also attentive to the needs of our employees and are sensitive to our social responsibility in the Rhine-Neckar Metropolitan Region,” Nick continued.

Together with Hans-Carsten Hansen, President Human Resources, Nick presented the status of current and planned BASF construction measures in Ludwigshafen both inside and outside of the site fence at a press conference held in Ludwigshafen.

Something that is new to the business world of Germany is a new Center for Work-Life Management that is being created in the next two years in direct proximity to the site. This center will bundle the diverse activities of BASF in the areas of career and family, sports and promotion of healthy living, and social and nursing care counseling at a single location. It will be built on the grounds between gate 2 and the Feierabendhaus, where the BASF day care center LuKids South is already located.

The day care offerings of LuKids for small children between the ages of six months and three years will be increased to accommodate a total of 250 children. Up until now, BASF SE has accommodated a total of 70 children at two locations in Ludwigshafen. After the expansion, the second location in the city district Pfingstweide will be closed. The ten places for temporary care at LuKids adhoc will remain at the LuKids South location.

“We want to offer the option of high-quality and flexible child care to as many parents as possible who work at BASF. This gives them the chance to better combine their career and family obligations and return to their work life after the birth of their children according to their personal planning ,” said Hans-Carsten Hansen, explaining the decision to expand the child care offerings.

In addition to LuKids, a modern health club will be established. This will include a comprehensive training infrastructure as well as advice and workshop offerings. The goal is to provide an attractive offering to employees for the maintenance of their health near the workplace, one that also contributes to greater fitness in the later years of work.

A team “Compatibility of career and family”, as well as the social counseling service of the BASF Social Foundation, will also be located at the new Center for Work-Life Management. The social counseling service covers a broad spectrum of services, ranging from debt and addiction counseling to guidance for psychosocial problems. The offerings will be extended to include nursing care counseling, which will help arrange nursing care services in cooperation with a service provider that operates nationwide. In future, more employees at BASF will have to make arrangements for nursing care for their relatives. The company wants to face this challenge proactively by offering comprehensive counseling.

“We want to employ the best team in the industry. We also want to ensure that we offer our employees optimal conditions for being this team,” explained Hansen. He is convinced that with the new Center for Work-Life-Management, BASF will become a pioneer among German companies and will continue to become more attractive as an employer. “The demographic shift is creating new challenges for the ability of our employees to work. We are actively addressing these topics with an integrated concept that is equally responsive to different life situations,” Hansen continued.

In addition, BASF’s Feierabendhaus will again be available as an event location and cafeteria starting at the end of the year. After a renovation period totaling 18 months, the Feierabendhaus will again open its doors with a celebratory concert on November 27, 2011, just in time for the 90-year anniversary of BASF´s cultural sponsoring.

In addition to projects outside of the site, several construction plans are also currently being implemented at the site. Also in this area BASF is pursuing the approach of maintaining buildings using intelligent solutions as long as fire codes and other regulations do not stand in the way of an efficient renovation. Where necessary, new buildings are being built on a targeted basis.

At BASF gate 2, the first preparations for the expansion of the BASF Visitor Center are currently underway. This is made possible through the relocation of the shower facility that was previously accommodated in the same building. In a first step, the Company Archive of BASF will be integrated into the building of the Visitor Center, thus making it even more accessible to outside guests. “It is already the case today that the Visitor Center is a real visitor magnet during the week and especially on the Saturdays that it is open. With the archive under the same roof, a fascinating combination is being created that invites visitors to look both back into the past and look forward into the future of BASF,” said Dr. Bernhard Nick.

The modernization of the neighboring Friedrich Engelhorn building – named after the founder of BASF – is currently running parallel to this. The building, which was opened in 1957, comprises 20 stories and is 102 meters tall, making it the tallest office building in Germany until 1962. Today it hosts a number of marketing and administrative units of BASF. In addition to the façade, the current modernization includes the office spaces and technical infrastructure of the building.

Some of the office buildings and storage spaces located near the Friedrich Engelhorn building are currently being prepared to be torn down. The previous company archive was located there as well. Further use of the building would have been associated with great expense and was thus not cost effective. At this location, an office building will be built by 2015. It will provide space for a cafeteria and several lecture and seminar rooms.

A further component of the investments in the infrastructure of the Ludwigshafen plant is a new concept for shower facilities that can be used by employees of BASF and contractor companies. For two shower facilities, the concept provides for incremental modernization; the previous shower facilities at gate 2 and gate 3 will be relocated due to the construction of a new building in the south section of the site. By the end of 2013, a building with changing rooms and showering facilities for 3,800 employees will be provided. It will be located between gate 1 and gate 7, where it is convenient to access by transportation. It will also have easy access to the rail station in the south section of the plant, where the new commuter rail connection will begin offering service starting in 2015.

A series of investments in production is currently being implemented. For example, as already announced, BASF is building a second production plant for Hexamoll® DINCH, doubling production capacity to 200,000 tons per year due to strong demand for this innovative plasticizer. BASF is also currently building the world’s largest production facility for the aroma chemical L-menthol at the Ludwigshafen site. A few weeks ago, the new distillation column of the plant was brought to the Ludwigshafen site via oversize transport. It is to be commissioned in 2012. With L-menthol, BASF is adding another attractive product to the citral value chain. This investment will create about 35 new jobs in Ludwigshafen.

By the end of 2011, the Styrodur® C plant will be expanded by 220,000 m3 to 1.52 million m3. As already reported at the beginning of August, BASF will be responding to the increased demand for innovative insulating materials for housing construction. The expansion work is occurring during ongoing operation, with completion scheduled for the end of 2011. Furthermore, the company is currently modernizing its acetylene plant, one of the site’s most important production facilities at the front of different value chains. The incremental implementation in the next four to five years safeguards the long-term supply of acetylene at the Ludwigshafen site.

The construction work that began in the spring of last year for the third construction phase of the intermodal transport terminal is running according to plan and should be complete by spring 2012. The terminal will be expanded to a total of 13 transshipment platforms and eight portal cranes. In the future, up to 500,000 loading units will be able to be handled annually in the terminal. That is 200,000 more loading units than today. The expanded terminal will cover 260,000 square meters, which corresponds to approx. 40 soccer fields.

The measures for further development of production are a component of investment planning within the scope of the ongoing Ludwigshafen Site Agreement. At the end of 2010, the company management and employee representatives came to an agreement on a variety of matters, including the investment of a total of €9 to 10 billion for the future viability of the Ludwigshafen Verbund site by 2015. From this total amount, €1.15 to 1.25 billion per year is to be provided for investments, modernization, and maintenance measures.