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.

Nitrogen in the soil cleans the air

 Eutrophication harms the environment in many ways. Unexpectedly, nitrogen fertilizer may also be positive for the environment. And even acidic soils, promoting the destruction of forests, can have a positive effect. Researchers from the Biogeochemistry Department at the Max Planck Institute for Chemistry in Mainz found out that nitrogen fertilizer indirectly strengthens the self-cleaning capacity of the atmosphere. Their study shows that nitrous acid is formed in fertilized soil and released to the atmosphere, whereby the amount increases with increasing soil acidity. In the air, nitrous acid leads to the formation of hydroxyl radicals oxidizing pollutants that then can be washed out. Previously, this nitrogen-effect has not been taken into account by geoscientists. The gap has now been closed by the Max Planck researchers.

Our air partly cleans itself as pollutants are being oxidized by hydroxyl radicals and washed out by rain. Now, researchers at the Max Planck Institute in Mainz and colleagues in Beijing have discovered the origin of a bulk part of the nitrous acid that is acting beside ozone as a source of hydroxyl radicals. According to their studies, large quantities of the acid are released into the atmosphere from soil. In nitrogen-rich soils the acid is formed from nitrite ions produced through microbiological transformations of ammonium and nitrate ions. The more acidic the soil is and the more nitrite it contains, the more nitrous acid is released. Through this pathway some of the nitrogen in fertilized soil escapes into the air.

In the latest issue of the journal Science, the Mainz researchers describe how they demonstrated the existence of this previously unnoticed pathway in the nitrogen cycle. They measured the concentration of HONO – a chemical term for gaseous nitrous acid – that escaped from a defined volume of arable soil. They added nitrite to a soil sample and varied its water content. The quantity of released HONO closely matched the researchers' estimates based on acid/base and solubility equilibria. Based on these findings they can also explain why previous studies had measured high levels of HONO in the air above fertilized agricultural soil.

The source of the high concentrations of HONO observed in the lower atmosphere had long been a mystery. "Soil is a complex system involving interactions between countless chemicals and biological organisms,” says Hang Su, the lead author of the paper. “Before us, no one seems to have investigated the soil-atmosphere exchange of nitrous acid".

The fact that soil emits HONO is not just locally, but also globally significant for air quality and the nitrogen cycle. "Next, we plan to work across disciplines with soil and climate researchers to quantify the effect in different types of soil and under different environmental conditions", adds research group leader Ulrich Pöschl. The findings will then be incorporated into a global model.

The Max Planck researchers suspect that soil-based HONO emissions could strongly increase especially in developing countries due to more extensive fertilization, soil acidification, and climate-related rise in temperature. This is expected to produce more hydroxyl radicals, which increase the oxidizing power of the air.

Original publication:
Hang Su, Yafang Cheng, Robert Oswald, Thomas Behrendt, Ivonne Trebs, Franz X. Meixner, Meinrat O. Andreae, Peng Cheng, Yuanhang Zhang & Ulrich Pöschl; "Soil nitrite as a source of atmospheric HONO and OH radicals"; Science, 18 August 2011