Science Highlights 2001

Science highlights of research occuring at the APS.

A High-Resolution Solution of the Ribosome Structure (Jul. 6)
The rRNA of the 30S ribosomal subunit, as determined at the Structural Biology Center. The parts of the rRNA as shown here are: messenger RNA (purple), head (green), central domain ((blue), and body (red) with H44 in cyan. The gold ribbons represent the binding from the anticodon stem loop. Researchers using high-brilliance x-ray beams from the Structural Biology Center undulator beamline 19-ID at the Advanced Photon Source have obtained a detailed picture of how the ribosome allows accurate translation of the genetic code. What they found offers new information on how proteins are formed and how they create the chain of proteins that make up an organism.
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APS FEL Achieves Ultraviolet Saturation (Jun. 8)
Measured intensity of the 530 nm optical signal as a function of distance down the undulator. The points are the measured data and the solid line is the simulation result. The Advanced Photon Source (APS) low-energy undulator test line (LEUTL) has achieved "saturation" of self-amplified spontaneous emission in a mirrorless free-electron laser at a wavelength over 1000 times shorter than the previous record. This important accomplishment demonstrated that such free-electron lasers based on this process may one day provide laser-quality x-ray beams and possibly open exciting new horizons for research in dozens of scientific fields.
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A High-Throughput 3-D X-ray Microtomography System with Real-Time 3-D Reconstruction (Apr. 10)
A rendered image from a three-dimensional tomographic reconstruction of a cricket, obtained with the x-ray microtomography system. The image has been digitally cut at different planes to show the internal structures of the cricket's head. A high-throughput x-ray microtomography system (XMS) that can acquire, reconstruct, and interactively display rendered 3-D images of a sample at micrometer-scale resolution within minutes has been developed at Advanced Photon Source (APS) beamline 2-BM, which is managed by the Synchrotron Radiation Instrumentation Collaborative Access Team (SRI-CAT). This system could bring better understanding of an array of scientific and technological problems, ranging from failure in microelectronic devices to structures in biological samples.
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Studying Materials Under Extreme Pressure (Mar. 3)
Image of the Earth's core. Researchers at the Advanced Photon Source have determined the phonon density of states for iron under pressures up to 153 gigapascals, equivalent to those found at the Earth's core. Proving long-held theories for iron at these pressures opens doors to a diverse array of basic and applied investigations, including seismological interpretation, planetary science, and the development of new thin-film materials, such as data-storage media.
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Finding a Link between Microbes and Mineral Deposits (Jan. 17)
Results of EDX (bottom left) and x-ray microprobe fluorescence (top right) analysis of specific biomineralized zinc sulfide precipitates. The sensitivity of the x-ray microprobe enables identification of arsenic and selenium constituents in the zinc sulfide precipitate. Scientists from the University of Wisconsin-Madison have found compelling evidence that micro-organisms play a central role in the formation of certain mineral deposits. These results shed light on the basic question of biology's function in the formation of some metal ores, and hold out the promise for applications in mining-site remediation.
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