. Scientific Frontline

Saturday, April 30, 2022

Researchers Create Self-Assembled Logic Circuits from Proteins

In a proof-of-concept study, researchers have created self-assembled, protein-based circuits that can perform simple logic functions. The work demonstrates that it is possible to create stable digital circuits that take advantage of an electron’s properties at quantum scales.

One of the stumbling blocks in creating molecular circuits is that as the circuit size decreases the circuits become unreliable. This is because the electrons needed to create current behave like waves, not particles, at the quantum scale. For example, on a circuit with two wires that are one nanometer apart, the electron can “tunnel” between the two wires and effectively be in both places simultaneously, making it difficult to control the direction of the current. Molecular circuits can mitigate these problems, but single-molecule junctions are short-lived or low-yielding due to challenges associated with fabricating electrodes at that scale.

“Our goal was to try and create a molecular circuit that uses tunneling to our advantage, rather than fighting against it,” says Ryan Chiechi, associate professor of chemistry at North Carolina State University and co-corresponding author of a paper describing the work.

Friday, April 29, 2022

Global warming accelerates the water cycle, with relevant climatic consequences

Global warming could lead to a destabilization of the global climate system
Credit: /ICM-CSIC.

According to a new study led by the ICM-CSIC, this could lead to a destabilization of the global climate system, an intensification of storms in specific areas, and an acceleration of ice melting at the poles.

Researchers at the Institut de Ciències del Mar (ICM-CSIC) in Barcelona have found that global warming is accelerating the water cycle, which could have significant consequences on the global climate system, according to an article published recently in the journal Scientific Reports.

This acceleration of the water cycle is caused by an increase in the evaporation of water from the seas and oceans resulting from the rise in temperature. As a result, more water is circulating in the atmosphere in its vapor form, 90 per cent of which will eventually precipitate back into the sea, while the remaining 10 per cent will precipitate over the continent.

New Model for Antibacterial Mechanism

Brookhaven Lab biologist Paul Freimuth and co-author Feiyue Teng, a scientist in Brookhaven Lab's Center for Functional Nanomaterials (CFN), at the light microscope used to image bacteria in this study.
Credit: Brookhaven National Laboratory

Biologists at the U.S. Department of Energy’s Brookhaven National Laboratory and their collaborators have discovered an aberrant protein that’s deadly to bacteria. In a paper just published in the journal PLOS ONE, the scientists describe how this erroneously built protein mimics the action of aminoglycosides, a class of antibiotics. The newly discovered protein could serve as a model to help scientists unravel details of those drugs’ lethal effects on bacteria—and potentially point the way to future antibiotics.

“Identifying new targets in bacteria and alternative strategies to control bacterial growth is going to become increasingly important,” said Brookhaven biologist Paul Freimuth, who led the research. Bacteria have been developing resistance to many commonly used drugs, and many scientists and doctors have been concerned about the potential for large-scale outbreaks triggered by these antibiotic-resistant bacteria, he explained.

“What we’ve discovered is a long way from becoming a drug, but the first step is to understand the mechanism,” Freimuth said. “We’ve identified a single protein that mimics the effect of a complex mixture of aberrant proteins made when bacteria are treated with aminoglycosides. That gives us a way to study the mechanism that kills the bacterial cells. Then maybe a new family of inhibitors could be developed to do the same thing.”

Revealing the secret language of dark matter

In the Universe, dark matter and standard matter “talk” to each other using a secret language. This “discussion” happens thanks to gravity, scientists say, but not in a way they can fully comprehend. A new SISSA study published in The Astrophysical Journal sheds light on this long-standing issue. The authors of the research, Ph.D Student Giovanni Gandolfi and supervisors Andrea Lapi and Stefano Liberati, propose a special property for dark matter called “non-minimal coupling with gravity”. This new type of interaction can modify dark matter gravitational influence on standard 'baryonic' matter.

According to the authors, the 'non-minimal coupling' could be the key to decrypting the enigmatic dialogue between the two components, possibly solving one of the biggest open questions about dark matter's nature. To prove the hypothesis, the assumption has been tested and then confirmed with experimental data from thousands of spiral galaxies.

The mysterious interplay with standard matter

“Dark matter is everywhere” says the research’s authors. “Like a cosmic scaffolding, it interconnects the Universe and holds galaxies together. Dark matter is as important as mysterious, though. Possibly, one of dark matter's greatest enigmas is its interplay with standard matter, or 'baryons'”. We know that in this dialogue gravity has an important role, but scientists still don’t entirely understand the phenomenon. “For this reason,” say Gandolfi, Lapi and Liberati “we asked ourselves: is gravity wrong or are we just missing something crucial about dark matter's nature? What if dark matter and standard 'baryonic' matter do not communicate in the way we have always imagined? With our research, we have tried to answer these intriguing questions”.

Fermilab engineers develop new control electronics for quantum computers that improve performance and cut costs

Gustavo Cancelo led a team of Fermilab engineers to create a new compact electronics board: It has the capabilities of an entire rack of equipment that is compatible with many designs of superconducting qubits at a fraction of the cost.
Photo: Ryan Postel, Fermilab

When designing a next-generation quantum computer, a surprisingly large problem is bridging the communication gap between the classical and quantum worlds. Such computers need specialized control and readout electronics to translate back and forth between the human operator and the quantum computer’s languages — but existing systems are cumbersome and expensive.

However, a new system of control and readout electronics, known as Quantum Instrumentation Control Kit, or QICK, developed by engineers at the U.S. Department of Energy’s Fermi National Accelerator Laboratory, has proved to drastically improve quantum computer performance while cutting the cost of control equipment.

“The development of the Quantum Instrumentation Control Kit is an excellent example of U.S. investment in joint quantum technology research with partnerships between industry, academia and government to accelerate pre-competitive quantum research and development technologies,” said Harriet Kung, DOE deputy director for science programs for the Office of Science and acting associate director of science for high-energy physics.

Engineers at UBC get under the skin of ionic skin

Dr. John Madden and Yuta Dobashi with one of the hydrogel sensors.
Photo by Kai Jacobson/UBC Faculty of Applied Science

In the quest to build smart skin that mimics the sensing capabilities of natural skin, ionic skins have shown significant advantages. They’re made of flexible, biocompatible hydrogels that use ions to carry an electrical charge. In contrast to smart skins made of plastics and metals, the hydrogels have the softness of natural skin. This offers a more natural feel to the prosthetic arm or robot hand they are mounted on, and makes them comfortable to wear.

These hydrogels can generate voltages when touched, but scientists did not clearly understand how — until a team of researchers at UBC devised a unique experiment, published in Science.

“How hydrogel sensors work is they produce voltages and currents in reaction to stimuli, such as pressure or touch – what we are calling a piezoionic effect. But we didn’t know exactly how these voltages are produced,” said the study’s lead author Yuta Dobashi, who started the work as part of his master’s in biomedical engineering at UBC.

Working under the supervision of UBC researcher Dr. John Madden, Dobashi devised hydrogel sensors containing salts with positive and negative ions of different sizes. He and collaborators in UBC’s physics and chemistry departments applied magnetic fields to track precisely how the ions moved when pressure was applied to the sensor.

Experts predict this hurricane season will only be slightly above average

Hurricane Ida, Tropical Storm Julian and Tropical Depression Ten - which intensified into Tropical Storm Kate on August 30 - as shown from NOAA's GOES-16 satellite on August 29, 2021.
Credit: NOAA

For the seventh year in a row, University of Arizona hurricane forecasters say to prepare for an above-average hurricane season, which runs from June 1 through Nov. 30. However, this year isn't expected to be as active as recent years.

The experts' forecast, released this month, shows 14 named storms and seven hurricanes developing over the Atlantic Ocean. Three of those seven hurricanes are expected to develop into major hurricanes – which are classified as category 3 or above. The UArizona experts also predict an accumulated cyclone energy, or ACE, index of 129 units. The ACE index provides a value for the combined strength and duration of a storm.

These predictions are only slightly higher than the seasonal median since 1980, which is 13 named storms and seven hurricanes, two of which are major hurricanes, and an ACE index of 107 units.

Professor of atmospheric sciences Xubin Zeng and former graduate student Kyle Davis developed their predictive model in 2014. It has since become one of the most accurate in the world for seasonal hurricane forecasting. It combines seasonal forecasts of sea surface temperature from the European Centre for Medium-Range Weather Forecasts with machine learning and the researchers' own understanding of hurricanes.

Thursday, April 28, 2022

Higher COVID-19 Death Rates in the Southern U.S. Due to Behavior Differences

During the pre-Omicron phases of the COVID-19 pandemic, regions of the U.S. had markedly different mortality rates, primarily due to differences in mask use, school attendance, social distancing and other behaviors. Had the entire country reacted to the pandemic as the Northeast region, more than 316,000 deaths might have been avoided, 62% of those avoidable deaths being in the South.

The study, by Georgetown University’s School of Nursing & Health Studies researchers, appeared April 28, 2022, in PLOS ONE.

Excess mortality, which helps account for avoidable deaths from a new disease or situation, is defined by the difference between total current deaths and deaths expected based on earlier time period, usually the previous decade or so. The U.S. Centers for Disease Control and Prevention (CDC) calculate these numbers weekly. For this study, the CDC excess mortality data were analyzed for the period between January 3, 2020, to September 26, 2021. For regional comparison purposes, areas of the country were broken down into the Northeast, Midwest, South and West.

“Our goal was to carefully examine regional differences in COVID-19 death rates based on reliable statistical data,” says Michael Stoto, PhD, professor of Health Systems Administration and Population Health at the School of Nursing & Health Studies and corresponding author of the study. “Our study is the first to quantify avoidable deaths and confirm that both COVID-19 deaths and avoidable deaths disproportionately occurred in the South.”

Diminishing Arctic Sea Ice Has Lasting Impacts on Global Climate

Source: University at Albany, State University of New York

As the impacts of climate change are felt around the world, no area is experiencing more drastic changes than the northern polar region. Studies have shown the Arctic is warming at two to three times as fast as the rest of the planet, resulting in a rapid loss of its sea ice volume.

The loss of sea ice, declining at an average rate of about 13 percent per decade, is having a long-lasting climatic impact in the Arctic and beyond, according to a new study published this month in Nature Communications.

The research team, led by University at Albany atmospheric scientist Aiguo Dai, analyzed observational data and climate model simulations to show how fluctuations in Arctic Sea ice cover are able to amplify multi-decadal variations in surface temperatures not only in the Arctic but also in the North Atlantic Ocean.

Their results indicate that recent – and future – decreases in sea ice cover have a significant influence on global climate.

“Through our study, we demonstrated for the first time that fluctuations in sea ice-air interactions can greatly enlarge or amplify multi-decadal climate variations not only in the Arctic, but also the North Atlantic,” said Dai, a distinguished professor in the Department of Atmospheric and Environmental Sciences.

Researchers Discover New Function Performed by Nearly Half of Brain Cells

Scientists say the discovery of a new function by cells known as astrocytes opens a whole new direction for neuroscience research.
Illustration Credit: Siena Fried

Researchers at Tufts University School of Medicine have discovered a previously unknown function performed by a type of cell that comprises nearly half of all cells in the brain.

The scientists say this discovery in mice of a new function by cells known as astrocytes opens a whole new direction for neuroscience research that might one day lead to treatments for many disorders ranging from epilepsy to Alzheimer’s to traumatic brain injury.

It comes down to how astrocytes interact with neurons, which are fundamental cells of the brain and nervous system that receive input from the outside world. Through a complex set of electrical and chemical signaling, neurons transmit information between different areas of the brain and between the brain and the rest of the nervous system.

Until now, scientists believed astrocytes were important, but lesser cast members in this activity. Astrocytes guide the growth of axons, the long, slender projection of a neuron that conducts electrical impulses. They also control neurotransmitters, chemicals that enable the transfer of electrical signals throughout the brain and nervous system. In addition, astrocytes build the blood-brain barrier and react to injury.

But they did not seem to be electrically active like the all-important neurons—until now.

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