Posts Tagged ‘ACTIVE’

How babies learn to walk holds potential clues to autism

“Our findings may allow us to identify the brain regions and networks that can predict aspects of autism before it’s possible to make a clinical diagnosis.”

Middle-age people: experts don’t think you walk fast enough

Citing concerns over a “shocking” level of inactivity among the middle-aged, officials at Public Health England want men and women between the ages of 40 and 60 to pick up the pace, so that they can complete at least one, brisk 10-minute walk per day, according to published reports. The organization estimated that just six […]

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High-spatial-resolution mapping of catalytic reactions on single particles

The critical role in surface reactions and heterogeneous catalysis of metal atoms with low coordination numbers, such as found at atomic steps and surface defects, is firmly established. But despite the growing availability of tools that enable detailed in situ characterization, so far it has not been possible to document this role directly. Surface properties can be mapped with high spatial resolution, and catalytic conversion can be tracked with a clear chemical signature; however, the combination of the two, which would enable high-spatial-resolution detection of reactions on catalytic surfaces, has rarely been achieved. Single-molecule fluorescence spectroscopy has been used to image and characterize single turnover sites at catalytic surfaces, but is restricted to reactions that generate highly fluorescing product molecules. Herein the chemical conversion of N-heterocyclic carbene molecules attached to catalytic particles is mapped using synchrotron-radiation-based infrared nanospectroscopy with a spatial resolution of 25 nanometres, which enabled particle regions that differ in reactivity to be distinguished. These observations demonstrate that, compared to the flat regions on top of the particles, the peripheries of the particles—which contain metal atoms with low coordination numbers—are more active in catalysing oxidation and reduction of chemically active groups in surface-anchored N-heterocyclic carbene molecules.

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