Philip Grandinetti and his colleagues are taking new, high-tech materials for a spin -- inside a nuclear magnetic resonance (NMR) instrument.     By Kevin Fitzsimons

Chemists spin materials to improve NMR data

An Ohio State chemist and his colleagues are taking new, high-tech materials for a spin -- inside a nuclear magnetic resonance (NMR) instrument.

The American, French and Danish researchers recently discovered that they can obtain more precise data about a material's atomic structure, and do it faster than ever before possible, if they spin the material at just the right speed inside the NMR instrument.

Philip Grandinetti, associate professor of chemistry at Ohio State, and his research partners have named their new technique FASTER, short for "Fast Spinning gives Transfer Enhancement at Rotary resonance."

FASTER eliminates the signal interference that plagues traditional techniques for studying materials using NMR.

In a recent issue of the Journal of Chemical Physics, the chemists reported that spinning samples at speeds of up to 30,000 cycles per second can, in many cases, boost the signal strength of the NMR measurements more than 10 times over.

"This is a big advance for people who want to study the atomic level structure of almost any solid material -- ceramics, plastics, glasses or catalysts," Grandinetti said. "Even for peptides, proteins or DNA, FASTER could shorten the time necessary for studying a substance from weeks to mere hours."

Grandinetti worked with three researchers at the French National Center for Scientific Research (CNRS) in Orleans: Thomas Vosegaard, now a research assistant professor at the University of Aarhus, Denmark; Pierre Florian, former postdoctoral fellow at Ohio State and now a research associate at CNRS; and Dominique Massiot, who directs the CNRS Center for High-Temperature Materials Research.

NMR works by tuning into the radio waves emitted by atoms within materials, Grandinetti explained. "Just as astronomers tune into the radio waves emitted by objects in outer space, we tune into radio waves emitted from inner space," he said.

Grandinetti likened the interference that confounds NMR signals to interference between stations on an FM radio. When a station is far away, music from other stations can drown it out.

In the case of atoms and molecules, the radio information that is lost concerns the environment of the atoms. That's because each atom emits radio waves at a particular frequency, depending on the type of atoms that surround them.

"The problem is, when we tune in our NMR Ôradios,' we receive a lot of static," Grandinetti said. "We try our best to reduce the noise, but these tiny signals from atomic nuclei are weak to begin with, so it's a battle to get a good signal."

The idea of spinning materials in an NMR instrument to improve the signal isn't new in itself. The original technique, known as magic-angle spinning (MAS), spins materials at a certain angle with respect to the NMR's magnetic field. Unfortunately, MAS doesn't work for 70 percent of known elements.

For these elements, including oxygen, aluminum and sodium, the rules of quantum mechanics prevent certain nuclear transitions from taking place, and it is those transitions that would reveal a clearer NMR signal.

The FASTER technique could be used by geologists, biologists, chemists and physicists, as well as materials scientists, since it works for any solid substance -- including minerals, biopolymers, enzymes and membranes.

Grandinetti plans to apply this advance to several different projects; one involves a study of the complex geochemistry that is occurring under nuclear waste storage tanks at the Department of Energy site in Hanford, Wash. Millions of gallons of radioactive waste from decades of nuclear weapons production are stored at the site, in tanks that are now leaking into the ground.

"It's an environmental nightmare," Grandinetti said, "and we desperately need a remediation strategy based on an accurate understanding of the chemistry taking place under these tanks."

Advances such as FASTER will help scientists characterize the minerals forming under these tanks, and understand their ability to immobilize materials leaking out, he added.

The National Science Foundation and the Department of Energy supported Grandinetti's part in this research.

Birth order affects career interests, study shows

A child's place in the family birth order may play a role in the type of occupations that will interest him or her as an adult, new research suggests. In two related studies, researchers found that only children -- and to a certain extent first-born children -- were more interested in intellectual, cognitive pursuits than were later-born children. In contrast, later-born children were more interested in both artistic and outdoors-related careers.

These results fit into theories that say our place in family birth order will influence our personality, said Frederick T.L. Leong, co-author of the study and professor of psychology.

"Parents typically place different demands and have different expectations of children depending on their birth order," Leong said. "For example, parents may be extremely protective of only children and worry about their physical safety. That may be why only children are more likely to show interest in academic pursuits rather than physical or outdoor activities. In addition, those who are an only child will tend to get more time and attention from their parents than children with siblings."

www.acs.ohio-state.edu/units/research/archive/birthwrk.htm