It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
From Wi-Fi-connected home security systems to smart toilets, the so-called Internet of Things brings personalization and convenience to devices that help run homes. But with that comes tangled electrical cords or batteries that need to be replaced. Now, researchers reporting in ACS Applied Energy Materials have brought solar panel technology indoors to power smart devices. They show which photovoltaic (PV) systems work best under cool white LEDs, a common type of indoor lighting.
Indoor lighting differs from sunlight. Light bulbs are dimmer than the sun, and sunlight comprises ultraviolet, infrared and visible light, whereas indoor lights typically shine light from a narrower region of the spectrum. Scientists have found ways to harness power from sunlight, using PV solar panels, but those panels are not optimized for converting indoor light into electrical energy. Some next-generation PV materials, including perovskite minerals and organic films, have been tested with indoor light, but it’s not clear which are the most efficient at converting non-natural light into electricity; many of the studies use various types of indoor lights to test PVs made from different materials. So, Uli Würfel and coworkers compared a range of different PV technologies under the same type of indoor lighting.
The researchers obtained eight types of PV devices, ranging from traditional amorphous silicon to thin-film technologies such as dye-sensitized solar cells. They measured each material’s ability to convert light into electricity, first under simulated sunlight and then under a cool white LED light.
Gallium indium phosphide PV cells showed the greatest efficiency under indoor light, converting nearly 40% of the light energy into electricity.
As the researchers had expected, the gallium-containing material’s performance under sunlight was modest relative to the other materials tested due to its large band gap.
A material called crystalline silicon demonstrated the best efficiency under sunlight but was average under indoor light.
Gallium indium phosphide has not been used in commercially available PV cells yet, but this study points to its potential beyond solar power, the researchers say. However, they add that the gallium-containing materials are expensive and may not serve as a viable mass product to power smart home systems. In contrast, perovskite mineral and organic film PV cells are less expensive and do not have stability issues under indoor lighting conditions. Additionally, in the study, the researchers identified that part of the indoor light energy produced heat instead of electricity — information that will help optimize future PVs to power indoor devices.
The authors acknowledge funding from the Engineering and Physical Sciences Research Council (U.K.), the European Regional Development Fund, the Welsh European Funding Office, First Solar Inc., the German Federal Ministry for Economic Affairs and Energy, and the German Research Foundation.
The American Chemical Society (ACS) is a nonprofit organization chartered by the U.S. Congress. ACS’ mission is to advance the broader chemistry enterprise and its practitioners for the benefit of Earth and all its people. The Society is a global leader in promoting excellence in science education and providing access to chemistry-related information and research through its multiple research solutions, peer-reviewed journals, scientific conferences, eBooks and weekly news periodical Chemical & Engineering News. ACS journals are among the most cited, most trusted and most read within the scientific literature; however, ACS itself does not conduct chemical research. As a leader in scientific information solutions, its CAS division partners with global innovators to accelerate breakthroughs by curating, connecting and analyzing the world’s scientific knowledge. ACS’ main offices are in Washington, D.C., and Columbus, Ohio.
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Developing next-gen traffic signal control systems with air quality in mind
Lehigh University CSE professor Yu Yang applies advanced machine learning techniques in NSF-funded research on traffic management and micromobility systems to reduce vehicle emissions and grow use of electric bikes and scooters
“THIS IS THE FIRST PROJECT OF ITS KIND TO INCORPORATE A SOCIAL COMPONENT INTO A TRAFFIC CONTROL SYSTEM,” SAYS LEHIGH CSE ASSISTANT PROFESSOR YU YANG. “WE’RE TAKING BOTH A TECHNICAL AND A SOCIAL PERSPECTIVE TO SOLVE A REAL-WORLD PROBLEM.”
CREDIT: PHOTO ILLUSTRATION BY KATIE KACKENMEISTER/LEHIGH UNIVERSITY
After a summer that broke all sorts of dismal records in terms of cataclysmic wildfires across North America, there is now an even greater awareness of poor air quality—its myriad health impacts and the overwhelming need for sustainable solutions.
To that end, Yu Yang, an assistant professor of computer science and engineering in Lehigh University’s P.C. Rossin College of Engineering and Applied Science, is leading two research projects, with new support from the National Science Foundation, ultimately aimed at improving the air we breathe.
The most recent award will fund his work using machine learning techniques to develop socially informed traffic signal control systems to reduce air pollution caused by vehicle emissions.
In dense urban areas, vehicles idling at stoplights can contribute to localized air pollution. It’s a problem for everyone—but especially for those with asthma and other health conditions that make them particularly sensitive to airborne particulate matter. Yang and his team are developing a three-pronged method that could allow for a more consistent traffic flow with fewer and/or shorter stops to minimize polluting emissions.
They’ll first develop a low-cost, mobile air-quality sensing system to identify areas of high pollution, and collect the social requirements of different areas. An area with a hospital, for example, might harbor large numbers of sensitive individuals.
“We’ll use those data to then develop a spatial-temporal graph diffusion learning model to determine the traffic situation in our test-bed city of Newark, New Jersey,” says Yang. “In other words, what is both the traffic and the air pollution like at different points of time in different locations?”
Finally, the researchers will use a reinforcement learning method that will incorporate traffic signals around the city, and simulate how traffic signal control helps improve air quality.
“This is the first project of its kind to incorporate a social component into a traffic control system,” says Yang. “We’re taking both a technical and a social perspective to solve a real-world problem.”
Ultimately, Yang envisions a traffic management system that would enable city transportation officials to control signals in real time, and a web-based system that would show city residents location-specific air quality levels so they can make informed decisions about what activities they do and where.
Yang’s work on traffic management for improved air quality extends to other modes of transportation, namely electric bikes and scooters. In a separate project, also supported by an NSF grant, he’s working on micromobility systems—shared systems where users rent these types of alternative vehicles for transportation—more efficient.
“Cities can have thousands of these vehicles, and so the problem becomes managing them, and making sure the location of the vehicles satisfies the demand for them,” he says.
He and his team are designing an algorithm to determine the best strategy for ensuring that, on a daily basis, sufficient numbers of vehicles are located in areas of high demand, and that those vehicles are sufficiently charged.
Their approach will also consider human-system interaction, like how people actually select and interact with the vehicles, he says. “The existing work in this area assumes that people just randomly pick their ride. But that’s not the case, people have preferences for things like how the bike or scooter looks and how much charge it has. Incorporating this kind of information will help us optimize our algorithm so it reflects how people actually use the system.”
He envisions a system that will generate a daily strategy based on the current location and charge level of all vehicles. “Based on the optimal strategy, then the operation center responsible for them can send out their trucks in the night to both charge and transport the bikes or scooters to the areas that will satisfy the next day’s demand.”
In both projects, the human element plays a key role, says Yang, and that’s what makes them exciting: “These are real problems that citizens are experiencing every day, and by incorporating how people are affected by and affect these systems, we can make them better for everyone.”
“Cities can have thousands of these [micromobility] vehicles, and so the problem becomes managing them, and making sure the location of the vehicles satisfies the demand for them,” says Yu Yang, an assistant professor of computer science and engineering at Lehigh University.
CREDIT
Photo illustration by Katie Kackenmeister/Lehigh University
IN A RECENT study PUBLISHED IN JAMA NETWORK OPEN, A TEAM AT The Ohio State University Wexner Medical Center LOOKED INTO A DRUG-FREE AND NON-INVASIVE ALTERNATIVE TO MANAGING PATIENTS’ PAIN AFTER C-SECTION. THE RESEARCH TEAM STUDIED THE USE OF A DEVICE THAT EMITS ELECTRICAL PULSES WHEN HELD NEAR THE C-SECTION INCISION SITE, AND THEY FOUND THAT PATIENTS WHO RECEIVED THE TREATMENT USED 47% LESS OPIOIDS TO CONTROL THEIR PAIN COMPARED TO THOSE WHO DID NOT RECEIVE THE TREATMENT.
THE HIGH FREQUENCY NEUROSTIMULATION DEVICE, CALLED TRUERELIEF, HAS TWO STAINLESS STEEL PROBES THAT ARE HELD NEAR THE C-SECTION INCISION SITE. THE PATIENT FEELS A VIBRATION DURING THE TREATMENT PROCESS WHICH LASTS A TOTAL OF 12 MINUTES. THE PROBES ARE MOVED ABOVE THE INCISION EVERY TWO MINUTES AND STIMULATE THE NERVES.
CREDIT: THE OHIO STATE UNIVERSITY WEXNER MEDICAL CENTER
JOURNAL
JAMA Network Open
METHOD OF RESEARCH
Randomized controlled/clinical trial
SUBJECT OF RESEARCH
People
ARTICLE TITLE
Noninvasive Bioelectronic Treatment of Postcesarean Pain
ARTICLE PUBLICATION DATE
20-Oct-2023
COI STATEMENT
TrueRelief LLC provided funding and devices for use in this trial, though did not have a role in the design and conduct of the study and collection, management, analysis and interpretation of the data.
Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.
Bacteria-virus arms race provides rare window into rapid and complex evolution
Intricate ecological networks emerge from simple beginnings that feature repeating patterns of evolutionary development
IN LABORATORY FLASKS CONTAINING JUST TWO TEASPOONS OF MEDIA, SCIENTISTS DOCUMENT HOW RAPID ADAPTATION BETWEEN BACTERIA AND VIRUSES PRODUCE COMPLEX ECOLOGICAL NETWORKS.
As conceived by Charles Darwin in the 1800s, evolution is a slow, gradual process during which species adaptations are inherited incrementally over generations. However, today biologists can see how evolutionary changes unfold on much more accelerated timescales.
Rather than the evocative plants and animals of the Galapagos Islands that Darwin studied in forming his theory of evolution, Postdoctoral Scholar Joshua Borin and Associate Professor Justin Meyer of UC San Diego’s School of Biological Sciences are documenting rapid evolutionary processes in simple laboratory flasks.
Borin and Meyer set bacteria and viruses together in a closed laboratory flask — just two teaspoons large — to study coevolution in action. As viruses infect their bacterial neighbors, the bacteria evolve new defensive measures to repel the attacks. The viruses then counter these adaptations with their own evolutionary changes that work around the new defensive measures.
In only three weeks, this accelerated arms race between bacteria (Escherichia coli) and viruses (bacteriophage, or “phage”) results in several generations of evolutionary adaptations. The new findings, published in the journal Science, reveal the emergence of distinct evolutionary patterns.
“In this study we show the power of evolution,” said Meyer, an associate professor in the Department of Ecology, Behavior and Evolution. “We see how coevolution between bacteria and phage drive the emergence of a highly complicated ecological network. Evolution doesn’t have to be slow and gradual as Darwin thought.”
Meyer says the new study offers fresh perspectives on how intricate ecological networks develop across disparate ecosystems, whether they are food webs across the savanna, pollinator networks in the rainforest or microbes interacting in the ocean.
As bacteria and viruses adapted to each other’s presence over time, two prominent repeating patterns emerged. These included nestedness, a development in which narrow interactions between bacteria and virus specialists are “nested” within a broader range of generalist interactions; and modularity, in which interactions between species form modules within specialized groups, but not between groups.
“We were amazed to discover that our evolution experiment in tiny flasks had recapitulated the complex patterns that had been previously observed between bacteria and viruses collected at regional and transoceanic scales,” said Borin.
“When our research team first quantified this multiscale pattern in environmental bacteria and phage interaction data, we thought the emergence of such complexity required long periods of evolution,” added study coauthor Professor Joshua Weitz from the Department of Biology at the University of Maryland.
Meyer says capturing these evolutionary developments “in action” reinforces the power of evolution, which is often underestimated. Rapid pathogenic evolution continues to shape our world in new ways. Through COVID-19 and new mutations of SARS-CoV-2, viruses have demonstrated the potent capability for evolutionary adaptations that result in new strains when they encounter antibodies, vaccines and other roadblocks that keep them from effectively infecting and spreading. Such new concepts in microbial evolution are reframing the way patients are treated.
“We show that evolution can produce complex ecological networks quickly from very little external help,” said Meyer, who indicated that examples of such external evolutionary forces include isolation via geographical distance, environmental drivers and interactions with other species. “So we can use phage and bacteria as a model system to understand general evolutionary principles and help show how life on Earth has evolved into such diverse and complex ecosystems from simple beginnings.”
In related work, Meyer and Weitz are using artificial intelligence to study how phage could be used in the growing antibiotic resistance crisis. The research includes analysis of evolutionary data to determine which mutations in phage and bacteria can lead to infection and resistance. The research also highlights a new effort supported by the Howard Hughes Medical Institute to study how “jumbo” phages could be used as new therapeutic agents.
Coauthors of the Science paper include Joshua Borin, Justin Lee, Adriana Lucia-Sanz, Krista Gerbino, Joshua Weitz and Justin Meyer.
AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE (AAAS)
Two studies highlight new glass- and ceramic-based passive radiative cooling materials. Unlike passive radiative cooling approaches that rely on polymers, these hard materials are more durable and versatile, making them more attractive for a wide range of outdoor passive cooling applications, including those that could help reduce the need for air conditioning. The energy demand for cooling continues to rise, particularly in regions rapidly warming due to climate change. To make matters worse, the growing carbon footprint of cooling systems further contributes to global warming, exacerbating the need for cooling solutions. Passive radiative cooling (PRC) materials, which are designed to reflect solar radiation and emit long-wavelength infrared (LWIR) thermal radiation through the atmosphere’s infrared window and back into outer space, are promising technologies that could mitigate both rising temperatures and cooling costs. However, developing effective PRC materials that are both environmentally robust and practical to manufacture has proven challenging. In this pair of studies, Xinpeng Zhao and colleagues and Kaixin Lin and colleagues, respectively describe microporous materials – a glass-based ceramic coating and a ceramic composite, respectively – that exhibit passive daytime radiative cooling and resistance to harsh environments.
The cooling glass-based ceramic coating developed by Zhao et al. uses a microporous glass silicon dioxide framework embedded with aluminum oxide (Al2O3) nanoparticles. The dual-particle approach produces a material that has both high solar reflectance and selective LWIR emission. What’s more, the addition of Al2O3 prevents densification of the microporous structure, which is crucial to its functionality, during manufacturing. According to the authors, the microporous glass coating enables a temperature drop of ~3.5 to 4 degrees Celsius, even under high-humidity conditions in both the daytime and nighttime respectively. It also maintains its high solar reflectance when exposed to harsh environments.
Inspired by the carapace of the whitest known insect on earth, Lin et al. developed a cooling ceramic composite composed of a hierarchically structured microporous Al2O3 framework that can achieve highly efficient light scattering, high thermal emission, and a near-perfect solar reflection of 99.6%. According to Lin et al., the ceramic demonstrated continuous sub-ambient cooling with a power of over 130 watts per square meter outdoors and at noon. “Although some structures with dynamic radiative cooling capabilities have been proposed and experimentally demonstrated recently, attaining large-scale applications remains a substantial challenge,” write Donliang Zhao and Huajie Tang in a related Perspective. “Nevertheless, the findings of Zhao et al. and Lin et al. advance cooling approaches that could, if commercially applied to buildings, drive down the electrical demand of air conditioners and benefit the environment.”
Most birds that flit through dense, leafy forests have a strategy for maneuvering through tight windows in the vegetation — they bend their wings at the wrist or elbow and barrel through.
But hummingbirds can't bend their wing bones during flight, so how do they transit the gaps between leaves and tangled branches?
A study published today in the Journal of Experimental Biology shows that hummingbirds have evolved their own unique strategies — two of them, in fact. These strategies have not been reported before, likely because hummers maneuver too quickly for the human eye to see.
For slit-like gaps too narrow to accommodate their wingspan, they scooch sideways through the slit, flapping their wings continually so as not to lose height.
For smaller holes — or if the birds are already familiar with what awaits them on the other side — they tuck their wings and coast through, resuming flapping once clear.
"For us, going into the experiments, the tuck and glide would have been the default. How else could they get through?" said Robert Dudley, a professor of integrative biology at the University of California, Berkeley, and senior author of the paper. "This concept of sideways motion with a total mix-up of the wing kinematics is quite amazing — it's a novel and unexpected method of aperture transit. They're changing the amplitude of the wing beats so that they're not dropping vertically when they do the sideways scooch."
Using the slower sideways scooch technique may allow birds to better assess upcoming obstacles and voids, thereby reducing the likelihood of collisions.
"Learning more about how animals negotiate obstacles and other 'building-blocks' of the environment, such as wind gusts or turbulent regions, can improve our overall understanding of animal locomotion in complex environments," noted first author Marc Badger, who obtained his Ph..D from UC Berkeley in 2016. "We still don't know very much about how flight through clutter might be limited by geometric, aerodynamic, sensory, metabolic or structural processes. Even behavioral limitations could arise from longer-term effects, such as wear and tear on the body, as hinted at by the shift in aperture negotiation technique we observed in our study."
Understanding the strategies that birds use to maneuver through a cluttered environment may eventually help engineers design drones that better navigate complex environments, he noted.
"Current remote control quadrotors can outperform most birds in open space across most metrics of performance. So is there any reason to continue learning from nature?" said Badger. "Yes. I think it's in how animals interact with complex environments. If we put a bird's brain inside a quadrotor, would the cyborg bird or a normal bird be better at flying through a dense forest in the wind? There may be many sensory and physical advantages to flapping wings in turbulent or cluttered environments."
Obstacle course
To discover how hummingbirds — in this case, four local Anna’s hummingbirds (Calypte anna) — slip through tiny openings, despite being unable to fold their wings, Badger and Dudley teamed up with UC Berkeley students Kathryn McClain, Ashley Smiley and Jessica Ye.
"We set up a two-sided flight arena and wondered how to train birds to fly through a 16-square- centimeter gap in the partition separating the two sides," Badger said, noting that the hummingbirds have a wingspan of about 12 centimeters (4 3/4 inches). "Then, Kathryn had the amazing idea to use alternating rewards."
That is, the team placed flower-shaped feeders containing a sip of sugar solution on both sides of the partition, but only remotely refilled the feeders after the bird had visited the opposite feeder. This encouraged the birds to continually flit between the two feeders through the aperture.
The researchers then varied the shape of the aperture, from oval to circular, ranging in height, width and diameter, from 12 cm to 6 cm, and filmed the birds’ maneuvers with high-speed cameras. Badger wrote a computer program to track the position of each bird’s bill and wing tips as it approached and passed through the aperture.
They discovered that as the birds approached the aperture, they often hovered briefly to assess it before travelling through sideways, reaching forward with one wing while sweeping the second wing back, fluttering their wings to support their weight as they passed through the aperture. They then swiveled their wings forward to continue on their way.
"The thing is, they have to still maintain weight support, which is derived from both wings, and then control the horizontal thrust, which is pushing it forward. And they're doing this with the right and left wing doing very peculiar things," Dudley said. "Once again, this is just one more example of how, when pushed in some experimental situation, we can elicit control features that we don't see in just a standard hovering hummingbird."
Alternatively, the birds swept their wings back and pinned them to their bodies, shooting through — beak first, like a bullet — before sweeping the wings forward and resuming flapping once safely through.
"They seem to do the faster method, the ballistic buzz-through, when they get more acquainted with the system," Dudley said.
Only when approaching the smallest apertures, which were half a wingspan wide, would the birds automatically resort to the tuck and glide, even though they were unfamiliar with the setup.
The team pointed out that only about 8% of the birds clipped their wings as they passed through the partition, although one experienced a major collision. Even then, the bird recovered quickly before successfully reattempting the maneuver and going on its way.
"The ability to pick among several obstacle negotiation strategies can allow animals to reliably squeeze through tight gaps and recover from mistakes," Badger noted.
Dudley hopes to conduct further experiments, perhaps with a sequence of different apertures, to determine how birds navigate multiple obstacles.
The work was funded primarily by a CiBER-IGERT grant from the National Science Foundation (DGE-0903711).
An Anna's hummingbird slips sideways between twigs, an unexpected maneuver that appears unique to hummingbirds.
PANELS A AND B SHOW THE SIDE-ON AND UNDERNEATH VIEW OF A HUMMINGBIRD PASSING THROUGH AN APERTURE SIDEWAYS. C AND D SHOW THE SAME VIEWS OF THE HUMMINGBIRD PASSING THOROUGH AN APERTURE LIKE A BULLET WITH ITS WINGS SWEPT BACK.
Soaring, wings outstretched, many birds sail through the air unhindered. However, species that dine on fruit, seeds and nectar must negotiate tiny gaps in cluttered foliage to secure a feast. To pass through apertures, many birds pull in their wings, folding them closer to their bodies. However, some of the most manoeuvrable aviators, hummingbirds, have lost the ability to fold their wings at the wrists and elbows. ‘Unless hummingbirds implement distinctive strategies to transit narrow apertures, they may be unable to enter gaps less than one wingspan wide’, says Marc Badger from University of California, Berkeley (UCB), USA. So how do the extraordinarily agile aeronauts, which can even fly backwards, negotiate the cluttered environments that make their homes? Teaming up with Kathryn McClain, Ashley Smiley, Jessica Ye and Robert Dudley (all from UCB), Badger set out to discover how Anna’s hummingbirds (Calypte anna) slip through tiny openings despite being unable to fold their wings in. The team publishes their discovery inJournal of Experimental Biology that they birds use two unique strategies that allow them to penetrate gaps that are barely half a wingspan wide.
‘We set up a two-sided flight arena and wondered how to train birds to fly through a 16 cm2 gap in the partition separating the two sides. Then Kathryn had the amazing idea to use alternating rewards’, says Badger, explaining that the team only refilled a flower-shaped feeder with a sip of sugar solution once the bird had returned to the feeder opposite, to encourage the ~12 cm wingspan birds to flit to and fro. Badger, Smiley and Ye then replaced the gap with a series of smaller oval and circular apertures – ranging in height, width and diameter from 12 to 6 cm – for the birds to negotiate, while they filmed the birds’ manoeuvres with high-speed cameras. Then, Badger wrote a computer program to methodically track the position of each bird’s bill as they approached and passed through each aperture, while also locating the bird’s wing tips, to calculate their wing positions as they transited through.
Impressively, the hummingbirds used two unique strategies to negotiate the gaps. In the first, they approached the aperture, often hovering in front of it to assess it first, before travelling through sideways, reaching forward with one wing while sweeping the second wing back – almost making the shape of a cross – while still fluttering their wings to fly through the aperture, then swivelling forward to continue on their way. In the second strategy, they swept their wings back, pinning them to their bodies, and shot through beak first like a bullet, before sweeping the wings forward and resuming flapping again once safely through.
Scrutinising the two strategies, the team realised that the birds that were travelling sideways tended to fly more cautiously and slowly than the birds that shot through the apertures beak first. And, as the birds became more familiar with the apertures after several approaches, they appeared to become more confident, approaching swiftly and dropping the more cautious sideways approach in favour of darting through beak first. However, the smallest aperture – half a wingspan wide – always presented the most difficulty, with every bird zipping through facing forward with their wings pinned back – even on the first attempt – to avoid collisions.
So, hummingbirds have developed strategies that allow them to penetrate tiny gaps less than a wingspan wide, with the sideways option enabling them to take a more cautious approach, transitioning to shooting through beak first as they become bolder. And the team points out that although ~8% of the birds clipped their wings as they passed through the partition, only one experienced a major collision, and even then, the bird recovered quickly before successfully reattempting the manoeuvre and going on its way.
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IF REPORTING THIS STORY, PLEASE MENTION JOURNAL OF EXPERIMENTAL BIOLOGY AS THE SOURCE AND, IF REPORTING ONLINE, PLEASE CARRY A LINK TO: https://journals.biologists.com/jeb/article-lookup/doi/10.1242/jeb.245643
REFERENCE: Badger, M., McClain, K., Smiley, A., Ye, J. and Dudley, R. (2023). Sideways maneuvers enable narrow aperture negotiation by free-flying hummingbirds. J. Exp. Biol.226, jeb245643. doi:10.1242/jeb.245643
DOI: 10.1242/jeb.245643
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