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<jats:p>Artificial-photosynthesis researchers dream of using sunlight's energy to generate chemical fuels. Despite progress, the approach must become more efficient and cheaper to make an impact on where the world gets its fuel.</jats:p>

<jats:p>Some researchers are looking to use artificial photosynthesis to generate hydrocarbon fuels like those we already burn. Their goal is essentially to run combustion in reverse.</jats:p>

<jats:p>The increasing interest in energy storage for the grid can be attributed to multiple factors, including the capital costs of managing peak demands, the investments needed for grid reliability, and the integration of renewable energy sources. Although existing energy storage is dominated by pumped hydroelectric, there is the recognition that battery systems can offer a number of high-value opportunities, provided that lower costs can be obtained. The battery systems reviewed here include sodium-sulfur batteries that are commercially available for grid applications, redox-flow batteries that offer low cost, and lithium-ion batteries whose development for commercial electronics and electric vehicles is being applied to grid storage.</jats:p>

<jats:p>Fuel cells are uniquely capable of overcoming combustion efficiency limitations (e.g., the Carnot cycle). However, the linking of fuel cells (an energy conversion device) and hydrogen (an energy carrier) has emphasized investment in proton-exchange membrane fuel cells as part of a larger hydrogen economy and thus relegated fuel cells to a future technology. In contrast, solid oxide fuel cells are capable of operating on conventional fuels (as well as hydrogen) today. The main issue for solid oxide fuel cells is high operating temperature (about 800°C) and the resulting materials and cost limitations and operating complexities (e.g., thermal cycling). Recent solid oxide fuel cells results have demonstrated extremely high power densities of about 2 watts per square centimeter at 650°C along with flexible fueling, thus enabling higher efficiency within the current fuel infrastructure. Newly developed, high-conductivity electrolytes and nanostructured electrode designs provide a path for further performance improvement at much lower temperatures, down to ~350°C, thus providing opportunity to transform the way we convert and store energy.</jats:p>

<jats:p>Structural data show that the light atom at the center of the nitrogenase active site cofactor is a carbon.</jats:p>

<jats:p>The 3.5 angstrom–resolution structure provides insights into the architecture of the eukaryotic ribosome and its regulation.</jats:p>

<jats:p>Observations with the Hubble Space Telescope show that halos of ionized gas are common around star-forming galaxies.</jats:p>

<jats:p>A galaxy that has experienced a recent burst of star formation has an extended halo of hot, ionized gas surrounding it.</jats:p>

<jats:p>Clouds of ionized gas located inside our Galaxy provide a major supply of matter for fueling ongoing star formation.</jats:p>

<jats:p>High-quality piezoelectric thin films are grown and exhibit superior properties for microelectromechanical systems.</jats:p>