Hitting the bullseye

Flexible: Electronic circuits on a film of polyimide from the Empa laboratory form synaptic transistors.
 Image: Empa

In the FOXIP project, researchers from Empa, EPFL and the Paul Scherrer Institute attempted to print thin-film transistors with metal oxides onto heat-sensitive materials such as paper or PET. The goal was ultimately not achieved, but those involved consider the project a success – because of a new printing ink and a transistor with "memory effect".

The bar was undoubtedly set high: In the research project Functional Oxides Printed on Polymers and Paper – FOXIP for short – the goal was to succeed in printing thin-film transistors on paper substrates or PET films. Electronic circuits with such elements play an important role in the growing Internet of Things (IoT), for example as sensors on documents, bottles, packaging ... – a global market worth billions.

If it were feasible to manufacture such transistors with inorganic metal oxides, this would open up a plethora of new possibilities. Compared with organic materials such as the semiconducting polymer polythiophene, explains project leader Yaroslav Romanyuk from Empa's Laboratory for Thin Films and Photovoltaics, the electrons in these materials are much more mobile. They could therefore significantly increase the performance of such elements and would not need to be protected against air and moisture with expensive encapsulation.

Researchers at SLAC use purified liquid xenon to search for mysterious dark matter particles

 Xenon purification system at SLAC. The two central columns are each filled with almost half a ton of charcoal, which is used to produce ultra-clean xenon for the LUX-ZEPLIN (LZ) dark matter experiment.
Resized Image using AI by SFLORG
Credit: Jacqueline Ramseyer Orrell/SLAC National Accelerator Laboratory

Sitting a mile below ground in an abandoned gold mine in South Dakota is a gigantic cylinder holding 10 tons of purified liquid xenon closely watched by more than 250 scientists around the world. That tank of xenon is the heart of the LUX-ZEPLIN (LZ) experiment, an effort to detect dark matter – the mysterious invisible substance that makes up 85% of the matter in the universe.

“People have been searching for dark matter for over 30 years, and no one has had a convincing detection yet,” said Dan Akerib, professor of particle physics and astrophysics at the Department of Energy’s (DOE) SLAC National Accelerator Laboratory. But with the help of scientists, engineers, and researchers around the globe, Akerib and his colleagues have made the LZ experiment one of the most sensitive particle detectors on the planet.

To reach that point, SLAC researchers built on their expertise in working with liquid nobles – the liquid forms of noble gases such as xenon – including advancing the technologies used to purify liquid nobles themselves and the systems for detecting rare dark matter interactions within those liquids. And, Akerib said, what researchers have learned will aid not only the search for dark matter, but also other experiments searching for rare particle physics processes.

“These are really profound mysteries of nature, and this confluence of understanding the very large and very small at the same time is very exciting,” Akerib said. “It’s possible we could learn something completely new about nature.”

Lockheed Martin Delivers Its Highest-Powered Laser to Date to U.S. Department of Defense

U.S. Army’s Indirect Fires Protection Capability-High Energy Laser (IFPC-HEL) Demonstrator laser weapon system.
Image credit: Lockheed Martin.

Lockheed Martin delivered to the Office of the Under Secretary of Defense for Research & Engineering OUSD (R&E) a new benchmark: a tactically-relevant electric 300 kW-class laser, the most powerful laser that Lockheed Martin has produced to date. This 300 kW-class laser is ready to integrate with the DOD demonstration efforts including the U.S. Army’s Indirect Fires Protection Capability-High Energy Laser (IFPC-HEL) Demonstrator laser weapon system.

The OUSD (R&E) selected Lockheed Martin in 2019 to scale its spectral beam combined high energy laser architecture to the 300 kW-class level as part of the High Energy Laser Scaling Initiative (HELSI), and the team recently achieved that milestone ahead of schedule.

“Lockheed Martin increased the power and efficiency and reduced the weight and volume of continuous-wave high energy lasers which reduces risk for future fielding efforts of high-power laser weapon systems,” said Rick Cordaro, vice president, Lockheed Martin Advanced Product Solutions.

The HELSI laser will support demonstration efforts with the Army’s IFPC-HEL, which is scheduled for laboratory and field testing this year.

Cells from miniature pigs are paving the way for improved stem cell therapies.

A breed of pigs called Wisconsin Miniature Swine — created by a team of UW–Madison scientists — will help researchers better model and understand human diseases.
Credit: Jeff Miller

A team led by University of Wisconsin–Madison Stem Cell & Regenerative Medicine Center researcher Wan-Ju Li offers an improved way to create a particularly valuable type of stem cell in pigs – a cell that could speed the way to treatments that restore damaged tissues for conditions from osteoarthritis to heart disease in human patients.

In a study published in Scientific Reports, Li’s team also provides insights into the reprogramming process that turns cells from one part of the body into pluripotent stem cells, a type of building block cell that can transform into any type of tissue. These new insights will help researchers study treatments for a wide range of diseases.

The researchers turned to pigs, a well-established animal model for potential human treatments, because translating research to improve human health is deeply important to Li, a professor of Orthopedics and Rehabilitation and Biomedical Engineering. He has spent much of his career studying cartilage and bone regeneration to develop innovative therapies to help people.

Li and members of his Musculoskeletal Biology and Regenerative Medicine Laboratory obtained skin cells from the ears of three different breeds of miniature pigs — Wisconsin miniature swine, Yucatan miniature swine and Göttingen minipigs.

Rochester researchers go ‘outside the box’ to delineate major ocean currents

Oceanic currents from satellite data overlaid with large scale circulation currents (gold lines) which can be extracted with a coarse graining technique developed in the lab of Hussein Aluie. Note the most energetic of these currents— the Antarctic Circumpolar Current—at lower left.
Credit: Benjamin Storer | University of Rochester

For the first time University of Rochester researchers have quantified the energy of ocean currents larger than 1,000 kilometers. In the process, they and their collaborators have discovered that the most energetic is the Antarctic Circumpolar Current, some 9,000 kilometers in diameter.

The team, led by Hussein Aluie, associate professor of mechanical engineering, used the same coarse-graining technique developed by his lab to previously document energy transfer at the other end of the scale, during the “eddy-killing” that occurs when wind interacts with temporary, circular currents of water less than 260 kilometers in size.

These new results, reported in Nature Communications, show how the coarse-graining technique can provide a new window for understanding oceanic circulation in all its multiscale complexity, says lead author Benjamin Storer, a research associate in Aluie’s Turbulence and Complex Flow Group. This gives researchers an opportunity to better understand how ocean currents function as a key moderator of the Earth’s climate system.

Chrysalis, the lost moon that gave Saturn its rings

Artistic rendering of the moon Chrysalis disintegrating in Saturn’s intense gravity field. The chunks of icy rock eventually collided and shattered into smaller pieces that became distributed in the thin ring we see today.
Image credit B. Militzer and NASA

Rings appear to be common around planets in the solar system, but the dramatic rings of Saturn have long puzzled astronomers, as has the steep tilt of the rings and the planet’s rotation axis relative to its orbit around the sun.

Scientists now show that the rings and the tilt are intimately linked, and that the key is a former moon of Saturn that was torn apart some 160 million years ago to form the rings. The researchers dubbed the lost moon Chrysalis because it blossomed into the rings much as a chrysalis transforms into a butterfly.

The new proposal for how Saturn became “Lord of the Rings” in our solar system and how Saturn got its axial tilt will be published this week in the journal Science. The lead author is Jack Wisdom, a professor of planetary science at the Massachusetts Institute of Technology (MIT), with key contributions from Burkhard Militzer at the University of California, Berkeley.

Militzer, UC Berkeley professor of earth and planetary science, was part of a team that in 2019 concluded that the rings of Saturn are relatively recent, having formed a mere 100 million years ago and perhaps even more recently. The planet itself is as old as the solar system, about 4.5 billion years. The rings could be debris left over from the tidal destruction of a former icy moon of Saturn or the remains of a comet that strayed too close to the planet.

Strawberries were smaller when bees ingested pesticides

Photo credit: Trollinho on Unsplash

Solitary bees that ingested the pesticide clothianidin when foraging from rapeseed flowers became slower. In addition, the strawberries pollinated by these bees were smaller. This is shown by a new study from Lund University in Sweden.

Strawberries are known to become bigger if bees have visited their flowers, but how strawberry growth is affected if the bees have been exposed to neonicotinoid insecticides has so far been unclear. In a new study published in PLOS ONE, a Swedish research team has made two discoveries.

“We studied bees that ingested clothianidin, a pesticide that was previously used in rapeseed to control flea beetles. Our study indicates that the substance made the bees slower and impaired their ability to pollinate the strawberry flowers”, says Lina Herbertsson, biology researcher at Lund University.

The researchers used twelve outdoor cages where solitary bees could forage from rapeseed and strawberry flowers. In half of the cages, the rapeseed had been treated with clothianidin. The bees that were exposed to the treated rapeseed needed more time than other bees to visit the same number of rapeseed flowers. When the researchers later weighed the strawberries, they made another discovery. It turned out that the strawberries were smaller if they had been pollinated by bees that foraged from clothianidin-treated rapeseed.

No-till management may reduce nitrous oxide gas releases, fight climate change

Mara Cloutier, shown here as a doctoral degree student in soil science and biogeochemistry, talking about the study at a field day, is now a project manager at the Soil Health Institute, based in Raleigh, North Carolina.
Credit: Pennsylvania State University

Scientists have long known that no-till farming reduces erosion and lessens water and nutrient runoff from crop fields, but now a new study by a team of Penn State researchers suggests that limiting soil disturbance may also diminish releases of nitrous oxide.

A greenhouse gas that contributes to climate change, nitrous oxide is 300 times more potent than carbon dioxide. To learn how no-till affects soil microbes that both produce and break down nitrous oxide, the researchers focused their study on a 40-year tillage experiment that has been maintained at Penn State’s Russell E. Larson Agricultural Research Center.

“We aimed to see whether the level of tillage in the long-term experiment affected the soil microbes responsible for net nitrous oxide emissions,” said team leader and study co-author Mary Ann Bruns, professor of soil microbiology and biogeochemistry in the College of Agricultural Sciences. “This is a particularly challenging objective because many diverse bacteria produce nitrous oxide, yet many others can convert it to an inert nitrogen gas that does not contribute to the greenhouse effect.”

The study, led by Mara Cloutier, a doctoral degree student in soil science and biogeochemistry when the research was conducted, collected and evaluated soil samples taken from plots that have been managed as no-till, chisel-disked or moldboard-plowed — three tillage practices that represent low-, intermediate- and high-intensity levels of physical disturbance, respectively — for four decades.

Study links length of REM sleep to body temperature

Credit: Lancet Neurology

Warm-blooded animal groups with higher body temperatures have lower amounts of rapid eye movement (REM) sleep, while those with lower body temperatures have more REM sleep, according to new research from UCLA professor Jerome Siegel, who said his study suggests that REM sleep acts like a “thermostatically controlled brain heater.”

The study in Lancet Neurology suggests a previously unobserved relationship between body temperature and REM sleep, a period of sleep when the brain is highly active, said Siegel, who directs the Center for Sleep Research at the Jane and Terry Semel Institute for Neuroscience and Human Behavior at UCLA.

Birds have the highest body temperature of any warm-blooded, or homeotherm, animal group at 41 degrees while getting the least REM sleep at 0.7 hours per day. That’s followed by humans and other placental mammals (37 degrees, 2 hours of REM sleep), marsupials (35 degrees, 4.4 hours of REM sleep), and monotremes (31 degrees, 7.5 hours of REM sleep).

Physicists generate new nanoscale spin waves

Illustration of the experiment
Photo: Dreyer et al, Nature Communications (CC-BY-SA 4.0)

Strong alternating magnetic fields can be used to generate a new type of spin wave that was previously just theoretically predicted. This was achieved for the first time by a team of physicists from Martin Luther University Halle-Wittenberg (MLU). They report on their work in the scientific journal "Nature Communications" and provide the first microscopic images of these spin waves.

The basic idea of spintronics is to use a special property of electrons - spin - for various electronic applications such as data and information technology. Spin is the intrinsic angular momentum of electrons that produces a magnetic moment. Coupling these magnetic moments creates the magnetism that could ultimately be used in information processing. When these coupled magnetic moments are locally excited by a magnetic field pulse, this dynamic can spread like waves throughout the material. These are referred to as spin waves or magnons.

A special type of those waves is at the heart of the work of the physicists from Halle. Normally, the non-linear excitation of magnons produces integers of the output frequency - 1,000 megahertz becomes 2,000 or 3,000, for example. "So far, it was only theoretically predicted that non-linear processes can generate spin waves at higher half-integer multiples of the excitation frequency," explains Professor Georg Woltersdorf from the Institute of Physics at MLU. The team has now been able to show experimentally which conditions are needed in order to generate these waves and to control their phase. Phase is the state of the oscillation of a wave at a certain point and time. "We are the first to confirm these excitations in experiments and have even been able to map them," says Woltersdorf.