ACS News Service Weekly PressPac: July 30, 2008

• New imaging technique reveals hidden details of a lost Van Gogh painting
• Keeping the crunch in the crust
• Perfectly proportioned legs keep water striders striding
• Turning those old electronic circuit boards into new park benches
• “Chiral” molecules pave the way for safer, more effective drugs

European researchers are reporting the first use of a powerful new imaging technique to reveal with unprecedented detail a Van Gogh under a Van Gogh — the portrait of a woman hidden underneath one of the fabled Dutch Master’s landscapes. Their study, which could provide new insights into the hidden details of other paintings, was scheduled for the July 29 online issue of ACS’ Analytical Chemistry, a bi-weekly publication.

Joris Dik and colleagues note that Vincent van Gogh, one of the founding fathers of modern painting, saved canvas by painting-over as many as one-third of his early period works with new or modified pictures. However, current imaging tools used by museums are unable to clearly visualize many of these hidden images, which offer unique and intimate insights into the artist’s works, the researchers say.

In the new study, the researchers used their new non-destructive technique, called Synchrotron Radiation-based X-Ray Fluorescence (XRF) Elemental Mapping, to analyze Van Gogh’s Patch of Grass painting. Although conventional imaging techniques previously showed that the painting contained the hidden image of a woman’s head, the details were blurred. The new technique reveals more detailed information about the chemical composition of the hidden paint layers. As a result, the scientists could construct a clearer and more colorful image of the hidden head. The image even includes brush strokes and facial features such as eyes, nose, mouth, and chin. The reconstructed image shows the dark, somber-head of a Dutch peasant woman, similar to a series of head portraits from Van Gogh’s early career, the researchers say. — MTS

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The amazing water strider — known for its ability to walk on water — came within just a hair of sinking into evolutionary oblivion. Scientists in France and the United Kingdom are reporting that the insect’s long, flexible legs have an optimal length that keeps it afloat. Their report is scheduled for the August 19 issue of ACS’ Langmuir, a bi-weekly journal.

In the new study, Dominic Vella notes that scientists already know much about the water-repellant structure of the water strider’s legs and how it allows them to efficiently scoot and jump on ponds and lakes. However, the insect’s many adaptations to life on water surfaces pose scientific puzzles. Solving those mysteries may have practical applications in the design of water-walking robots that can support the maximum possible payload, they note.

Building on earlier work by scientists at Carnegie Mellon University, Vella developed a mathematical model to determine the maximum weight load that a thin, flexible cylinder — representing a water strider’s legs — can support on a liquid surface without sinking. He found that as the length of the cylinder increases, the maximum load at first increases but then reaches a plateau at some critical length. After that length, the cylinder begins to bend and is not able to support more weight. Comparing the model to measurements on museum specimens, Vella found that the strider’s legs are typically slightly shorter than the critical length. This suggests that the water strider’s legs are just the right length: Long enough to provide maximum weight support but not long enough to bend and hinder the insect’s movement, he says. — MTS

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In the drive to create safer, more effective drugs for cancer, Parkinson’s disease, and other health challenges, researchers worldwide are stepping up efforts to produce purer substances based on a molecule’s unique symmetry or chirality, according to an article scheduled for the August 4 issue of Chemical & Engineering News.

In the C&EN cover story, Senior Correspondent Ann M. Thayer points out that in the pharmaceutical world, a molecule’s right- or left-handed symmetry determines whether it does good or ill in the body. Today, about 70 percent of new small-molecule drugs that the Food & Drug Administration approved in 2007 contained at least one chiral molecule as its central active component.

But creating one specific configuration of mirror image molecules rather than a mixture remains a challenge, as these molecules are complex and difficult for chemists to construct. But thanks to increased cooperation between academia and industry, chemists are identifying new catalysts and reactions to produce chiral compounds faster, more efficiently, and with fewer environmental risks, such as metal contaminants, the article notes. Although these processes will likely remain unknown to the average consumer, health and the environment will benefit in the long run, the article suggests.

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• ACS’s 236th National Meeting, August 17-21, Philadelphia

One of 2008’s largest and most important scientific conferences — the 236th National Meeting and Exposition of the American Chemical Society — will be held Aug. 17-21, 2008, in Philadelphia, Pa. At least 12,000 scientists and others are expected for the event, which will include more than 8,000 reports on new discoveries in chemistry. The multi-disciplinary theme is Chemistry for Health: Catalyzing Transitional Research. Watch Eurekalert for embargoed press releases, a schedule of onsite press briefings that will be available via the Internet, and other information.

• The ACS Annual Report

The 2007 ACS annual report, Our Science, Our Lives, Our Stories, can be a valuable resource for journalists trying to keep pace with chemistry and the multiple fields of science that involve chemistry. The report features ACS members describing in their own words why they became chemists, what they find rewarding about their work and how the transforming power of chemistry helps address mounting global problems and improves people’s lives. Some are humorous, some are poignant. All of them are compelling. The newly published report is at: http://www.acsannualreport.org/acsannualreport/2007.

• Pfizer’s work on penicillin becomes National Historic Chemical Landmark

Pfizer’s deep-tank fermentation — a revolutionary process that enabled mass production of penicillin for use in World War II — was designated a National Historic Chemical Landmark by the American Chemical Society (ACS) in a special ceremony in Brooklyn, N.Y., on June 12. The process ushered in the era of antibiotics and represented a turning point in modern medicine. After World War II, Pfizer applied its deep-tank fermentation to manufacture the antibiotics streptomycin and Terramycin^®, which proved effective against a wide range of deadly bacteria. For more information, click here for the press release.

• ChemMatters Matters for Journalists

This quarterly ACS magazine for high school chemistry students, teachers, and others explains the chemistry that underpins everyday life in a lively, understandable fashion. ChemMatters is available at www.acs.org/chemmatters. You can also receive the most recent issues by contacting the editor, Pat Pages, at: 202-872-6164 or chemmatters@acs.org.

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• Global Challenges/Chemistry Solutions

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