Friday, May 20, 2022

Neuromorphic Memory Device Simulates Neurons and Synapses​

A neuromorphic memory device consisting of bottom volatile and top nonvolatile memory layers emulating neuronal and synaptic properties, respectively
Credit: KAIST

Researchers have reported a nano-sized neuromorphic memory device that emulates neurons and synapses simultaneously in a unit cell, another step toward completing the goal of neuromorphic computing designed to rigorously mimic the human brain with semiconductor devices.

Neuromorphic computing aims to realize artificial intelligence (AI) by mimicking the mechanisms of neurons and synapses that make up the human brain. Inspired by the cognitive functions of the human brain that current computers cannot provide, neuromorphic devices have been widely investigated. However, current Complementary Metal-Oxide Semiconductor (CMOS)-based neuromorphic circuits simply connect artificial neurons and synapses without synergistic interactions, and the concomitant implementation of neurons and synapses still remains a challenge. To address these issues, a research team led by Professor Keon Jae Lee from the Department of Materials Science and Engineering implemented the biological working mechanisms of humans by introducing the neuron-synapse interactions in a single memory cell, rather than the conventional approach of electrically connecting artificial neuronal and synaptic devices.

Neuroscientists Find Brain Mechanism Tied to Age-Related Memory Loss

As the brain ages, a region in the hippocampus becomes imbalanced, causing forgetfulness. Scientists say understanding this region of the brain and its function may be the key to preventing cognitive decline.

Working with rats, neuroscientists at Johns Hopkins University have pinpointed a mechanism in the brain responsible for a common type of age-related memory loss. The work, published in Current Biology, sheds light on the workings of aging brains and may deepen our understanding of Alzheimer's disease and similar disorders in humans.

"We're trying to understand normal memory and why a part of the brain called the hippocampus is so critical for normal memory," said senior author James Knierim, a professor at the university's Zanvyl Krieger Mind/Brain Institute. "But also with many memory disorders, something is going wrong with this area."

Neuroscientists know that neurons in the hippocampus, located deep in the brain's temporal lobe, are responsible for a complementary pair of memory functions called pattern separation and pattern completion. These functions occur in a gradient across a tiny region of the hippocampus called CA3.

In normal brains, pattern separation and pattern completion work hand-in-hand to sort and make sense of perceptions and experiences, from the most basic to the highly complex. If you visit a restaurant with your family and a month later you visit the same restaurant with friends, you should be able to recognize that it was the same restaurant, even though some details have changed—this is pattern completion. But you also need to remember which conversation happened when, so you do not confuse the two experiences—this is pattern separation.

Superconductivity and charge density waves caught intertwining at the nanoscale

Artist's rendering of an infrared laser quenching charge density waves.
Credit: Greg Stewart/SLAC National Accelerator Laboratory

Room-temperature superconductors could transform everything from electrical grids to particle accelerators to computers – but before they can be realized, researchers need to better understand how existing high-temperature superconductors work.

Now, researchers from the Department of Energy's SLAC National Accelerator Laboratory, the University of British Columbia, Yale University and others have taken a step in that direction by studying the fast dynamics of a material called yttrium barium copper oxide, or YBCO.

The team reports May 20 in Science that YBCO's superconductivity is intertwined in unexpected ways with another phenomenon known as charge density waves (CDWs), or ripples in the density of electrons in the material. As the researchers expected, CDWs get stronger when they turned off YBCO's superconductivity. However, they were surprised to find the CDWs also suddenly became more spatially organized, suggesting superconductivity somehow fundamentally shapes the form of the CDWs at the nanoscale.

Boomerang’ effect in droplets could help clean sensitive surfaces

 A water-alcohol-propylene glycol droplet expands and then contracts, an effect that could be used to help remove particles from sensitive surfaces such as microchips.
Credit: Cornell University College of Engineering

While brooms and sponges are the means of choice to fight contamination in everyday life, cleaning sensitive surfaces such as electronic components require different tools, including evaporation-based methods that often leave behind small particles on the surface.

Through their work on the dynamics of liquid mixtures, scientists at Cornell’s Meinig School of Biomedical Engineering and the Max Planck Institute for Dynamics and Self-Organization have developed a new approach to the problem. The method uses liquid droplets that first spread out on surfaces and then contract again on their own – a boomerang effect that leaves virtually no traces when the droplets contract, unlike conventional drying, opening up new possibilities for cleaning and removing particles from sensitive surfaces such as microchips.

New study reveals the global impact of debris on marine life

Dr Sarah Gall
Credit: University of Plymouth

Nearly 700 species of marine animal have been recorded as having encountered man-made debris such as plastic and glass, according to the most comprehensive impact study in more than a decade.

Researchers at Plymouth University found evidence of 44,000 animals and organisms becoming entangled in, or swallowing debris, from reports recorded from across the globe.

Plastic accounted for nearly 92 per cent of cases, and 17 per cent of all species involved were found to be threatened or near threatened on the IUCN Red List, including the Hawaiian monk seal, the loggerhead turtle and sooty shearwater.

In a paper, 'The impact of debris on marine life', published in Marine Pollution Bulletin, authors Sarah Gall and Professor Richard Thompson present evidence collated from a wide variety of sources on instances of entanglement, ingestion, physical damage to ecosystems, and rafting, where species are transported by debris.

The missing piece to faster, cheaper and more accurate 3D mapping

The authors: Davide A. Cucci, Aurélien Brun and Jan Skaloud.
Credit: Alain Herzog/EPFL

Engineers at EPFL and the University of Geneva believe they hold the key to automated drone mapping. By combining artificial intelligence with a new algorithm, their method promises to considerably reduce the time and resources needed to accurately scan complex landscapes. It is described in a paper published in ISPRS Journal of Photogrammetry and Remote Sensing.

Three-dimensional (3D) mapping is a very useful tool for monitoring construction sites, tracking the effects of climate change on ecosystems and verifying the safety of roads and bridges. However, the technology currently used to automate the mapping process is limited, making it a long and costly endeavor.

“Switzerland is currently mapping its entire landscape using airborne laser scanners – the first time since 2000. But the process will take four to five years since the scanners have to fly at an altitude below one kilometer if they are to collect data with sufficient detail and accuracy,” says Jan Skaloud, a senior scientist at the Geodetic Engineering Laboratory (Topo) within EPFL's School of Architecture, Civil and Environmental Engineering (ENAC).

Artificial intelligence predicts patients’ race from their medical images

Researchers demonstrated that medical AI systems can easily learn to recognize racial identity in medical images, and that this capability is extremely difficult to isolate or mitigate.
 Credit: Massachusetts Institute of Technology

The miseducation of algorithms is a critical problem; when artificial intelligence mirrors unconscious thoughts, racism, and biases of the humans who generated these algorithms, it can lead to serious harm. Computer programs, for example, have wrongly flagged Black defendants as twice as likely to reoffend as someone who’s white. When an AI used cost as a proxy for health needs, it falsely named Black patients as healthier than equally sick white ones, as less money was spent on them. Even AI used to write a play relied on using harmful stereotypes for casting.

Removing sensitive features from the data seems like a viable tweak. But what happens when it’s not enough?

New breathable gas sensors may improve monitoring of health, environment

Huanyu “Larry” Cheng, assistant professor of engineering science and mechanics at Penn State, newly developed flexible, porous and highly sensitive nitrogen dioxide sensors that can be applied to skin and clothing.
Credit: Penn State/Kate Myers

Newly developed flexible, porous and highly sensitive nitrogen dioxide sensors that can be applied to skin and clothing have potential applications in health care, environmental health monitoring and military use, according to researchers.

Led by Huanyu “Larry” Cheng, assistant professor of engineering science and mechanics at Penn State, the researchers published their sensor designs, which build on previous models, and results in ACS Applied Materials and Interfaces.

The sensors monitor nitrogen dioxide, either from breath if attached under the nose, or from perspiration, if attached elsewhere on the body. Unlike taking blood samples, the direct skin attachment allows for continuous, long-term monitoring of the gas.

Cheng explained that while similar sensors exist, a key differentiator of the new design is breathability.

“The commonly used substrate materials for gas sensors are flexible, but not porous,” he said. “The accumulation of water moisture from the skin surface can potentially lead to irritation or damage to the skin surface. We need to make sure the device can be porous so that moisture can go through the sensor without accumulation on the surface.”

Thursday, May 19, 2022

Bird Flu: How It’s Spreading and What to Know About This Outbreak

A feeding frenzy of western sandpipers during the mass migration via Cordova, Alaska, a key study site in the paper.
Credit: Wendy Puryear

When it comes to avian influenza, more commonly known as bird flu, all birds are not created equal.

“The scientific community has become accustomed to speaking about influenza viruses in birds as a group, but birds are an incredibly diverse taxa of animals with different natural history, physiology, and anatomy,” says Jonathan Runstadler, professor and chair of the Department of Infectious Disease & Global Health at Cummings School of Veterinary Medicine.

Runstadler is one of the authors of a new study, published today in the journal PLOS Pathogens, which takes a data-driven look at influenza viruses circulating among different groups of birds and characterizes which types of birds are involved in spreading the virus. The timing of this paper is impeccable, as a highly pathogenic strain of bird flu has been spreading across North America.

This lineage of bird flu originated around 1996 and was first found in a domestic goose in China. The virus mutated and persisted, and the first big wild bird outbreak happened around 2005 in a major wetland in central Asia. Subsequent changes in the virus led to a 2014 introduction to the U.S. via the Pacific Northwest, severely affecting the U.S. poultry industry and forcing the culling of about 40 million turkeys and chickens as a control measure.

PFAS chemicals do not last forever

Once dubbed “forever chemicals,” per-and polyfluoroalkyl substances, or PFAS, might be in the market for a new nickname.

That’s because adding iodide to a water treatment reactor that uses ultraviolet (UV) light and sulfite destroys up to 90% of carbon-fluorine atoms in PFAS forever chemicals in just a few hours, reports a new study led by environmental engineering researchers at UC Riverside. The addition of iodide accelerates the speed of the reaction up to four times, saving energy and chemicals.

“Iodide is really doing some substantial work,” said corresponding author Jinyong Liu, an assistant professor of chemical and environmental engineering. “Not only does it speed up the reaction but it also allows the treatment of a ten times higher concentrations of PFAS, even some very recalcitrant structures.”

Liu’s lab has been working on ways to destroy PFAS through photochemical reactions since 2017. The new method has already attracted interest from industry and Liu’s group is partnering with companies to conduct pilot tests.

Synthetic chemicals known as PFAS contain multiple very strong carbon-fluorine bonds. Widespread use of these nonbiodegradable compounds in countless products since the 1940s has contaminated water supplies across America, with various negative health effects on humans and animals. Because the carbon-fluorine bond is very hard to break, PFAS pass through most water treatment systems unchanged.

Featured Article

Newly Discovered Lake May Hold Secret to Antarctic Ice Sheet’s Rise and Fall

The coast of Antarctica is near where the East Antarctic Ice Sheet meets the sea. Credit: Shuai Yan/UT Jackson School of Geosciences Scienti...

Top Viewed Articles