Science & Research Highlights 2002

Image of knotted protein.

First Knot Discovered in Ancient Bacterium Protein

DECEMBER 13, 2002

The first knotted protein from the most ancient type of single-celled organism, an archaebacterium, has been discovered by researchers from Argonne National Laboratory and the University of Toronto using the Advanced Photon Source (APS) at Argonne.
The structure of the key protein that enables quorum-sensing bacteria to communicate and spread infection.

Breaking the Code of Cell Communication

SEPTEMBER 17, 2002

A method that cells use to communicate and coordinate activities has been confirmed by researchers from Cornell University, Monsanto Co., and Argonne. This work could lead to new drugs for the fight against such diseases as cystic fibrosis and the bubonic plague, or to new technologies that perform useful environmental tasks such as filtering water.
For the material investigated in this study, microtomography has proven to be an extremely useful tool for tracking changes in fluid saturation, as shown in this CMT image.

Using CMT to Determine Gas- and Liquid-phase Distributions in Porous Media

JUNE 3, 2002

Understanding how water flows through unsaturated subsurface environments is important on a number of levels, not least of which is in devising environmental remediation and restoration schemes for contaminated sites. Using the GeoSoilEnviroCARS Collaborative Access Team computed microtomography (CMT) instrument at Advanced Photon Source sector 13, researchers have applied CMT to gain a fundamental understanding of flow and transport mechanisms function in porous media.
Defraction Rings

High-Energy X-ray Diffraction Study of Internal Stresses in Metal Matrix Composites

MAY 3, 2002

Metal matrix composites (MMCs) comprise an intriguing new class of materials coming to prominence in the aerospace, electronics, and automotive industries. Internal stresses play an important role in the behavior and successful application of MMCs and multi-phase alloys. Researchers from the University of Stuttgart and Northwestern University have used the high-energy, high-flux x-rays available at the Advanced Photon Source to study the internal load transfer in particle-reinforced copper matrix composites at much increased speed. The study emphasizes the fact that high-energy synchrotron x-ray beams are a powerful tool for studying the mechanics of metal matrix composites.
Geometry for x-ray diffraction from the asymmetric 202 crystal planes of Ge[001]

>A Switch in Time: A New Path to Subpicosecond X-ray Pulses

APRIL 17, 2002

Switching hard x-ray beams on and off rapidly enough to capture the motion of atoms is the goal of one research project under way at the MHATT-CAT beamlines at Argonne National Laboratory's Advanced Photon Source. Perfecting this technique may enable the development of a sub-picosecond x-ray switch fast enough to track dynamic changes in molecular structure during chemical and biochemical reactions.
InsulinB peptide binding to human HLA-DQ8 and pocket P9 (see end of article for complete description)

Illuminating Clues to the Prevention of Juvenile Diabetes

MAY 3, 2002

More than 700,000 Americans are afflicted with Type 1 diabetes. Type 1 diabetes (scientific name: insulin-dependent diabetes mellitus or IDDM; colloquial name: juvenile diabetes) typically begins before age 40. The peak age of diagnosis in the U.S. is approximately 14. Researchers from the Children's Hospital and the Howard Hughes Medical Institute, and the Dana-Farber Cancer Institute, using an Advanced Photon Source (APS) beamline managed by the BioCARS Collaborative Access Team, have discovered important clues that promise to further research into the prevention of IDDM.
Conceptual view of the 6-lens array system. This system would provide sufficient data to generate a 3-dimensional image of a tumor.

A Copper Crystal Lens for Ultrahigh-Sensitivity Medical Imaging

MARCH 6, 2002

A copper crystal lens developed at the Advanced Photon Source represents a new and promising approach in nuclear medicine for imaging very small tumors in the human body with higher sensitivity and higher spatial resolution than the cameras now in use. The crystal diffraction 6-lens array should be able to detect tumors as small as 2 mm in diameter with a factor of 10 to 20 times higher sensitivity than gamma cameras. Moreover, it can provide sufficient information to locate a tumor accurately in three dimensions and eliminate false position determination.
Backscattered electron image of the quenched laser-heated diamond anvil cell sample from 31 GPa and 1976K. ( J.-F. Lin et al.)

Unearthing the Composition of Our Planet's Core

MARCH 6, 2002

The chemical composition of the Earth's core is surprisingly complicated, according to high-temperature, high-pressure experiments conducted by University of Chicago scientists using the William M. Keck High Pressure Laboratory at the GSECARS facility, APS sector 13. This research has produced experimental evidence suggesting that the Earth's inner core largely consists of two exotic forms of iron (rather than one as previously thought) that appear to be alloyed with silicon.
Time-resolved radiographic images of fuel sprays and attendant shock waves for time instances from 38 to of 192 s after injection start. (A.G. MacPhee et al).

X-ray Imaging of Shock Waves Generated by High-Pressure Fuel Sprays

MARCH 6, 2002

High-pressure, high-speed fuel sprays are a critical technology for many applications including fuel injection systems, where the structure and dynamics of the fuel sprays is the key to increasing fuel efficiency and reducing pollutants. Because liquid sprays are difficult to image, high-pressure fuel sprays have never been considered as supersonic under typical fuel injection conditions. At SRI-CAT (the Advanced Photon Source) and the Cornell High Energy Synchrotron Source, synchrotron x-radiography and a fast x-ray detector were used to record the time evolution of transient fuel sprays from a high-pressure injector, capturing the propagation of spray-induced shock waves in a gaseous medium and revealing the complex nature of the spray hydrodynamics.
Partial representation of the edema factor structure

Edema Factor: Revealing the Structure of an Anthrax Toxin

FEBRUARY 22, 2002

Edema factor (EF) is one of three toxins that make anthrax a deadly biohazard. Researchers using the BioCars and Structural Biology Center beamlines at the Advanced Photon Source and beamlines X25 and X4 at the National Synchrotron Light Source have determined the three- dimensional structure of EF. This discovery provides important new information that may lead to the design of pharmaceuticals to counteract the effects of bacterial toxins such as anthrax.