Story tips from the Department of Energy's Oak Ridge National Laboratory, March 2019

Neutrons—Fighting superbugs 

As the rise of antibiotic-resistant bacteria known as superbugs threatens public health, Oak Ridge National Laboratory’s Shuo Qian and Veerendra Sharma from the Bhaba Atomic Research Centre in India are using neutron scattering to study how an antibacterial peptide interacts with and fights harmful bacteria. Using Bio-SANS and BASIS, instruments at ORNL’s neutron scattering facilities, the researchers used neutrons’ unique hydrogen sensitivity to observe the model membranes of the hydrogen-rich bacteria while the peptide, known as aurein 1.2, caused instability in the bacteria and affected their movement. “Because bacteria are charged and our body cells are neutral, aurein can target harmful bacteria, bind with them and neutralize them,” said Qian. “We aren’t looking at aurein and bacteria membranes independently; we’re looking at the interactions between both.” The researchers’ findings could help improve antibiotics and make them more effective in fighting superbugs. This research was published in Langmuir. — Josh Witt [Contact: Kelley Smith, (865) 576-5668; [email protected]] 

Image: https://www.ornl.gov/sites/default/files/2019-03/Neutrons-FightingSuperbugs.jpg 

Caption: Neutron scattering allowed direct observation of how aurein induces lateral segregation in the bacteria membranes, which creates instability in the membrane structure. This instability causes the membranes to fail, making harmful bacteria less effective. Reprinted with permission from “Effect of an Antimicrobial Peptide on Lateral Segregation of Lipids, a Structure and Dynamics Study by Neutron Scattering,” Veerendra Kumar Sharma and Shuo Qian. Langmuir. Copyright 2019. American Chemical Society. 

Ecology—When air becomes wood

Higher carbon dioxide levels caused 30 percent more wood growth in young forest stands across the temperate United States over a decade, according to an analysis led by Oak Ridge National Laboratory. Scientists examined large-scale experimental plots using mixed model analysis to determine if carbon dioxide caused growth in fast turnover tissues such as roots and leaves or if it resulted in trees with taller, wider trunks that capture and hold carbon dioxide in the wood. “We used methods that take site-to-site variation into account and give a population-level result,” said ORNL’s Anthony Walker. “This provided an estimate of the broader response of these ecosystems to the atmospheric carbon dioxide concentrations of the future.” Studying these changes on a decadal scale improves climate modeling. The findings, published in Nature Communications, are an outcome of the Department of Energy’s carbon dioxide enrichment experiments conducted at ORNL, Rhinelander, Duke and Kennedy Space Center. [Contact: Kim Askey, (865) 576-2841; [email protected]] 

Image: https://www.ornl.gov/sites/default/files/2019-03/ORNL_FACE_1_TP-2010-169.JPG 

Caption: Trees in an Oak Ridge National Laboratory plot and others across the United States were exposed to elevated levels of carbon dioxide. An analysis of four experimental forests shows woody biomass increased 30 percent more over a decade compared to trees in the current atmosphere. Credit: Jeff Warren/Oak Ridge National Laboratory, U.S. Dept. of Energy 

Nuclear—Follow your senses 

Oak Ridge National Laboratory is using ultrasonic additive manufacturing to embed highly accurate fiber optic sensors in heat- and radiation-resistant materials, allowing for real-time monitoring that could lead to greater insights and safer reactors. Nuclear reactors are highly instrumented to monitor such variables as temperature and pressure, but no currently available sensor can monitor a reactor component’s structural health during operation when exposed to extreme temperatures and radiation. With additive manufacturing, the highly accurate, radiation-hard sensors are embedded in structures or components. “Fiber optic sensors are unique because they provide spatially distributed measurements, showing what’s happening across the entire system, not just a single point,” said ORNL’s Chris Petrie. “For advanced reactors, you could embed these sensors in locations where it would otherwise be impossible to detect the location and premature nature of component failures.” Researchers have tested the process by embedding sensors in nickel-based alloys and heating them to 500 degrees Celsius. [Contact: Jason Ellis, (865) 241-5819; [email protected]] 

Image: https://www.ornl.gov/sites/default/files/2019-03/Nuclear-Follow_your_senses_ORNL_1.jpg 

Caption: ORNL nuclear engineer Chris Petrie has led the research into using ultrasonic additive manufacturing to embed fiber optic sensors for nuclear applications. The development could embed sensors in advanced reactor components or structures, providing greater insights into how the reactors operate. Credit: Carlos Jones/Oak Ridge National Laboratory, U.S. Dept. of Energy 

Datasets—Measuring the dark 

Geospatial scientists at Oak Ridge National Laboratory analyzed three cities of varying infrastructures to look for patterns of electricity use and locate “dark spots” where informal neighborhoods may lack access to power. Using nighttime lights data layered over satellite images, scientists could see clusters of light versus spots of darkness. They applied machine learning techniques to high-resolution satellite imagery to detect similarities in densely populated urban settings, widely spread suburban neighborhoods and rural areas across the international cities studied. “This method presents a scalable way to fill in energy consumption data in places without readily available information on a city’s electricity consumption,” said ORNL’s Jeanette Weaver, co-author of a published study led by Pranab Roy Chowdhury of the University of Washington. “These patterns on a regional scale could ultimately help inform urban planning decision making on a local level.” The team will expand their datasets to include more points of interest. [Contact: Sara Shoemaker, (865) 576-9219; [email protected]] 

Image: https://www.ornl.gov/sites/default/files/2019-03/dJ_Neighborhoods_solo.png 

Caption: ORNL scientists applied machine learning to analyze the infrastructure of Johannesburg, South Africa, and two other global cities, to look for patterns of electricity use and locate "dark spots" where informal neighborhoods may lack access to power. Credit: Oak Ridge National Laboratory, U.S. Dept. of Energy 

Transportation—Logging the miles 

Oak Ridge National Laboratory’s latest Transportation Energy Data Book: Edition 37 reports that the number of vehicles nationwide is growing faster than the population, with sales more than 17 million since 2015, and the average household vehicle travels more than 11,000 miles per year. ORNL researchers compile transportation data from 50 different existing sources for the Department of Energy, analyzing trends in petroleum, energy, light (cars, sport utility vehicles, pick-up trucks) vehicles, heavy trucks, household vehicle characteristics and alternative fuel. This tool provides accurate data on transportation activity that can help inform policy makers and analysts. “Cars and light trucks account for a significant amount of energy consumption, using 59 percent of all transportation energy,” said ORNL researcher Stacy Davis. “Transportation also accounts for almost 16 percent of all household expenditures.” The Transportation Energy Data Book publishes yearly and is available as a user-friendly online reference. [Contact: Jennifer Burke, (865) 576-3212; [email protected]]

Image: https://www.ornl.gov/sites/default/files/2019-03/Transportation-Logging_the_miles_ORNL.jpg 

Caption: Published yearly by ORNL for the Department of Energy, the Transportation Energy Data Book analyzes trends in petroleum, energy, light vehicles, heavy trucks, household vehicle characteristics and alternative fuel. Credit: Oak Ridge National Laboratory, U.S. Dept. of Energy