March 7, 2014Retroviruses like HIV-1, which causes AIDS, go to a lot of trouble to replicate themselves and further their infectious cycles. While the molecular details of this process are known, one mystery is how HIV-1 recognizes and fishes out its own RNA from among all the other RNAs in the nucleus, an essential step in viral replication. New research at the U.S. Department of Energy Office of Science′s Advanced Photon Source has defined the protein-structural basis for this process and may also help in the design of drugs that target HIV-1 infection for treatment of patients with AIDS.
February 26, 2014The key to understanding what causes changes in material conductivity lies in teasing out contributions from structural atomic arrangements and electron interactions. Researchers using high-energy x-rays from the U.S. Department of Energy Office of Science′s Advanced Photon Source disentangled these components in vanadium sesquioxide. By decoupling the effects of spin, charge, and lattice variables, they uncovered a mechanism that has eluded researchers for six decades.
February 24, 2014Light-emitting diodes use significantly less energy and have far longer lifetimes than do traditional incandescent bulbs. Scientists are using high-brightness x-rays from the U.S. Department of Energy Office of Science′s Advanced Photon Source to help explore and fine-tune new compounds in the form of nanoribbons that luminesce brightly in different colors and make more appealing white lights based on light-emitting diodes.
February 17, 2014Experiments at the U.S. Department of Energy Office of Science′s Advanced Photon Source studied the changes occurring in the domain pattern and atomic structure of a superlattice. These insights have the potential to extend the functionalities of complex oxides by providing the means to tune the field and time dependences of a material′s electronic properties, perhaps paving the way for their use in new, multifunctional microelectronic devices.
January 29, 2014When thin films of ferroelectric materials are grown on single-crystal substrates, they can develop domains with complex patterns. Changing the properties of the substrate and interfaces of the materials can control the size and shape of the domains and influence the material′s behavior, so to understand details of local polarization, it is important to accurately image the domains. At the U.S. Department of Energy Office of Science′s Advanced Photon Source, researchers utilized Bragg projection ptychography for ferroelectric domain imaging, potentially improving critical technologies such as memory storage.
January 27, 2014Toxic vehicle emissions, such as carbon monoxide and unburned hydrocarbons, are chemically converted to benign compounds by catalytic converters, which are valuable but expensive. To reduce costs, experiments are being done to lessen the amount of platinum and substitute palladium in the converters. Research at the U.S. Department of Energy Office of Science′s Advanced Photon Source indicates that a palladium/lanthanum-alumina catalyst may result in a reduced-cost catalytic converter with improved low-temperature carbon monoxide oxidation reactivity.
January 23, 2014Contrary to popular opinion, the iron found in the Earth's core is relatively weak. That is the finding from experiments carried out using x-rays from two U.S. Department of Energy Office of Science light sources including the Advanced Photon Source at Argonne National Laboratory show that. This weakness may explain how the crystal structure in the Earth's core has transformed over geological time scales.
January 22, 2014All organisms have mechanisms that they use to repair DNA damaged by ultraviolet light. New research shows that the current model for how UV repair functions must be reworked. Researchers from Harvard University utilizing the U.S. Department of Energy Office of Science’s Advanced Photon Source provide new insights into the fundamental mechanisms of DNA repair and into diseases that are caused by mutations in these genes.