Category: Science

A new tiny, self-driving robot powered only by surrounding light or radio waves can run indefinitely on harvested power.

Small mobile robots carrying sensors could perform tasks like catching gas leaks or tracking warehouse inventory. But moving robots demands a lot of energy, and batteries, the typical power source, limit lifetime and raise environmental concerns.

Researchers have explored various alternatives: affixing sensors to insects, keeping charging mats nearby, or powering the robots with lasers. Each has drawbacks. Insects roam. Chargers limit range. Lasers can burn people’s eyes.

Researchers have now created MilliMobile, a self-driving robot that is about the size of a penny, weighs as much as a raisin, and can move about the length of a bus (30 feet, or 10 meters) in an hour even on a cloudy day.

The robot can drive on surfaces such as concrete or packed soil and carry nearly three times its own weight in equipment like a camera or sensors. It uses a light sensor to move automatically toward light sources.

“We took inspiration from ‘intermittent computing,’ which breaks complex programs into small steps, so a device with very limited power can work incrementally, as energy is available,” says co-lead author Kyle Johnson, a doctoral student in the Paul G. Allen School of Computer Science & Engineering at the University of Washington.

“With MilliMobile, we applied this concept to motion. We reduced the robot’s size and weight so it takes only a small amount of energy to move. And, similar to an animal taking steps, our robot moves in discrete increments, using small pulses of energy to turn its wheels.”

The team tested MilliMobile both indoors and outdoors, in environments such as parks, an indoor hydroponic farm, and an office. Even in very low light situations—for instance, powered only by the lights under a kitchen counter—the robots are still able to inch along, though much slower.

Running continuously, even at that pace, opens new abilities for a swarm of robots deployed in areas where other sensors have trouble generating nuanced data.

The robots are also able to steer themselves, navigating with onboard sensors and tiny computing chips. To demonstrate this, the team programmed the robots to use their onboard light sensors to move towards a light source.

“‘Internet of Things’ sensors are usually fixed in specific locations,” says co-lead author Zachary Englhardt, a doctoral student in the Allen School. “Our work crosses domains to create robotic sensors that can sample data at multiple points throughout a space to create a more detailed view of its environment, whether that’s a smart farm where the robots are tracking humidity and soil moisture, or a factory where they’re seeking out electromagnetic noise to find equipment malfunctions.”

Researchers have outfitted MilliMobile with light, temperature, and humidity sensors as well as with Bluetooth, letting it transmit data over 650 feet (200 meters). In the future, they plan to add other sensors and improve data-sharing among swarms of these robots.

The team will present its research October 2 at the ACM MobiCom 2023 conference in Madrid, Spain.

Vicente Arroyos, a doctoral student in the Allen School, is a co-lead author of the study. Dennis Yin, who completed this work as undergraduate in electrical and computer engineering, and Shwetak Patel, a professor in the Allen School and in electrical and computer engineering, are coauthors, and Vikram Iyer, assistant professor in the Allen School, is the study’s senior author.

The research received funding from an Amazon Research Award, a Google Research Scholar award, the National Science Foundation Graduate Research Fellowship Program, the National GEM Consortium, the Washington NASA Space Grant Consortium, the Pastry-Powered T(o)uring Machine Endowed Fellowship, and the SPEEA ACE fellowship program.

Source: University of Washington

Violence was a consistent part of life among ancient communities of hunter-gatherers, according to new research in northern Chile.

Archaeological research has shown that interpersonal violence and warfare played an important role in the lives of hunter-gatherer groups over time. Still, many questions remain about the factors that influenced such violence.

The record of human populations in northern Chile extends across 10,000 years, providing a valuable opportunity to study patterns in violence over time. For the study in PLOS ONE, researchers looked for signs of trauma on 10,000-year-old skeletal remains from burial sites there.

John Verano, a biological anthropologist and professor at Tulane University, specializes in examining ancient and modern human skeletons.

For the study, he collaborated with lead author Vivien Standen of the University of Tarapacá, Chile, to investigate potential cases of skull fractures and their timing. They analyzed whether the injuries had healed or were likely to be fatal and determined if the wounds were accidental or caused by interpersonal violence.

In the study, the researchers examined signs of violent trauma on the remains of 288 adult individuals from funerary sites across the Atacama Desert coast, dating from 10,000 years ago to 1450 CE. The group also analyzed patterns in weaponry and artistic depictions of combat during this time.

They found that rates of violence were surprisingly static over time. However, a notable increase in lethal violence during the Formative Period started around 1000 BCE, a trend also found in similar studies of the Andean region.

Data from strontium isotopes indicate that this interpersonal violence occurred between local groups, not between local and foreign populations.

The results indicate that violence was a consistent part of the lives of these ancient populations for many millennia.

The absence of a centralized political system during this time might have led to the consistency of violent tensions in the region. It’s also possible that violence resulted from competition for resources in the extreme environment of the desert, a factor which might have become exacerbated as farming became more prominent and widespread.

Source: Tulane University

A new survey finds that a majority of computer science experts at top US research universities want to see the creation of a new federal agency or global organization to govern artificial intelligence.

The Axios-Generation Lab-Syracuse University AI Experts Survey of computer science professors found that 37% favored a new “Department of AI” to regulate AI, while 22% thought a global organization or treaty was the best option. These findings compared with 16% of respondents who said Congress was the best entity to regulate AI, while 4% said the responsibility falls on the White House, and 3% mentioned the private sector. About 14% of respondents said AI cannot be regulated, while 3% said AI should not be regulated.

Generation Lab conducted the survey for Axios in partnership with Syracuse University’s Institute for Democracy, Journalism and Citizenship (IDJC) and the Autonomous Systems Policy Institute (ASPI).

Margaret Talev, director of the IDJC, says the survey offered a different and important perspective on the expanding conversation about the uses and proliferation of AI.

“While larger general-population surveys can provide broad insights into most Americans’ hopes, fears, and understanding of AI, this new survey offers an in-depth look at how computer science professors with significant subject-matter expertise are thinking about the same issues,” says Talev, who is also an Axios senior contributor.

“This survey provides valuable information about the current state of AI because it is based on the views of those who are closely involved in the development of AI techniques and systems,” adds Hamid Ekbia, director of the ASPI.

Some other key survey findings:

• About 62% predict AI will increase racial, gender, and economic disparities.
• Respondents also predict that customer service; art, design, or content creation; and administrative and support services are most likely to experience job losses due to AI over the next five years.
• No single person is highly trusted to deal with AI issues; President Biden ranked higher than individual tech CEOs.

The Axios-Generation Lab-Syracuse University AI Experts Survey was conducted July 15–August 6. Results are based on interviews with 213 computer science professors from 65 of the top 100 computer science programs in America, as defined by SCImago Institutions Rankings. Experts from Syracuse University were among those surveyed.

A listing of the participating institutions and additional details about the methodology may be found on the Generation Lab website.

Source: Syracuse University

A new climate study finds that temperature fluctuations in the tropical Atlantic Ocean are largely driven by human-induced aerosol emissions, affecting rainfall in West Africa’s Sahel region and hurricane formation in the Atlantic.

The findings, published in the journal Nature, come in a year when several hurricanes, including Hurricane Idalia, formed within days of each other over the tropical Atlantic.

“Our findings suggest the waxing and waning in Atlantic ocean temperature, hurricanes, and Sahel rainfall are largely driven by human-induced emissions,” says lead author Chengfei He, a postdoctoral researcher at the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science. “The novel results are hidden in the noise and can only be revealed by new techniques.”

The researchers used a grand ensemble simulation technique that took the average of more than 400 climate model simulations from climate centers worldwide. The technique showed the climate changes resulting from external forcings—a force on the climate system that mainly comes from human activities and volcanic eruptions.

“For a long time, changes in the West African rainfall and Atlantic hurricanes were believed to be driven by natural cycles within the climate system, such as the Atlantic Meridional Overturning Circulation,” says coauthor Amy Clement, a professor of atmospheric sciences at the Rosenstiel School. “Now we have found that the forced climate changes in our model simulations closely match the real-world observations seen in the tropical Atlantic.”

The results from these simulations suggest that suppressed Atlantic hurricane activity and a drier Sahel in the decades following World War II were mostly driven by human-caused aerosol emissions. West Africa’s Sahel region stretches south of the Saharan desert from the Atlantic to the Red Sea.

This culminated in drought in the early 1980’s with food shortages and diseases resulted in over hundreds of thousands of lives lost from West Africa to Ethiopia. The reduction in aerosol emissions after the 1980s resulted in more Atlantic hurricanes and more Sahel rainfall. The results also showed similarities in sea surface temperature, hurricane activity, and Sahel rainfall that closely matches what scientists observe in the tropical Atlantic.

The researchers also note that there are many factors that influence the activity in hurricane season, and that storms can and will occur even if the overall activity of a hurricane season is low.

“Due to the continuous reduction in human-induced aerosol emissions around the Atlantic, along with ongoing and future warming due to greenhouse gases, we suggest there will likely not be a return to the quiet period in hurricane activity in the Atlantic in the decades of the mid-century,” says He.

Additional coauthors are from the University of Miami, the University of Colorado, and Columbia University.

The study had support from NOAA, the Climate and Large-Scale Dynamics program of the National Science Foundation, and the Paleo Perspectives on Climate Change program of the National Science Foundation.

Source: Amy Reisewitz for University of Miami

A compound found in many plants inhibits the growth of drug-resistant Candida fungi, including its most virulent species, Candida auris, in the lab, a study finds.

The journal ACS Infectious Diseases has published a paper on the discovery.

Laboratory-dish experiments showed that the natural compound, a water-soluble tannin known as PGG, blocks 90% of the growth in four different species of Candida fungi. The researchers also discovered how PGG inhibits the growth: It grabs up iron molecules, essentially starving the fungi of an essential nutrient.

By starving the fungi rather than attacking it, the PGG mechanism does not promote the development of further drug resistance, unlike existing antifungal medications. Laboratory-dish experiments also showed minimal toxicity of PGG to human cells.

“Drug-resistant fungal infections are a growing health care problem but there are few new antifungals in the drug-development pipeline,” says Cassandra Quave, senior author of the study and associate professor in Emory School of Medicine’s department of dermatology and the Center for the Study of Human Health. “Our findings open a new potential approach to deal with these infections, including those caused by deadly Candida auris.”

C. auris is often multidrug-resistant and has a high mortality rate, leading the Centers for Disease Control and Prevention (CDC) to label it a serious global health threat.

“It’s a really bad bug,” says Lewis Marquez, first author of the study and a graduate student in the molecular systems and pharmacology program. “Between 30 to 60% of the people who get infected with C. auris end up dying.”

Candida is a yeast often found on the skin and in the digestive tract of healthy people. Some species, such as Candida albicans, occasionally grow out of control and cause mild infections in people.

In more serious cases, Candida can invade deep into the body and cause infections in the bloodstream or organs such as the kidney, heart, or brain. Immunocompromised people, including many hospital patients, are most at risk for invasive Candida infections, which are rapidly evolving drug resistance.

In 2007, the new Candida species, C. auris, emerged in a hospital patient in Japan. Since then, C. auris has caused health care-associated outbreaks in more than a dozen countries around the world with more than 3,000 clinical cases reported in the United States alone.

An ethnobotany approach

Quave is an ethnobotanist, studying how traditional people have used plants for medicine to search for promising new candidates for modern-day drugs. Her lab curates the Quave Natural Product Library, which contains 2,500 botanical and fungal natural products extracted from 750 species collected at sites around the world.

“We’re not taking a random approach to identify potential new antimicrobials,” Quave says. “Focusing on plants used in traditional medicines allows us to hone in quickly on bioactive molecules.”

Previously, the Quave lab had found that the berries of the Brazilian peppertree, a plant used by traditional healers in the Amazon for centuries to treat skin infections and some other ailments, contains a flavone-rich compound that disarms drug-resistant staph bacteria.

Screens by the Quave lab had also found that the leaves of the Brazilian peppertree contain PGG, a compound that has shown antibacterial, anticancer, and antiviral activities in previous research.

PPG vs. pathogens

A 2020 study by the Quave lab, for instance, found that PGG inhibited growth of Carbapenem-resistant Acinetobacter baumannii, a bacterium that infects humans and is categorized as one of five urgent threats by the CDC.

The Brazilian peppertree, an invasive weed in Florida, is a member of the poison ivy family.

“PGG has popped up repeatedly in our laboratory screens of plant compounds from members of this plant family,” Quave says. “It makes sense that these plants, which thrive in really wet environments, would contain molecules to fight a range of pathogens.”

The Quave lab decided to test whether PGG would show antifungal activity against Candida.

Laboratory-dish experiments demonstrated that PGG blocked around 90% of the growth in 12 strains from four species of Candida: C. albicans, multidrug-resistant C. auris, and two other multidrug-resistant non-albicans Candida species.

PGG is a large molecule known for its iron-binding properties. The researchers tested the role of this characteristic in the antifungal activity.

“Each PGG molecule can bind up to five iron molecules,” Marquez explains. “When we added more iron to a dish, beyond the sequestering capacity of the PGG molecules, the fungi once again grew normally.”

Dish experiments also showed that PGG was well-tolerated by human kidney, liver, and epithelial cells.

“Iron in human cells is generally not free iron,” Marquez says. “It is usually bound to a protein or is sequestered inside enzymes.”

Next steps

Previous animal studies on PGG have found that the molecule is metabolized quickly and removed from the body. Instead of an internal therapy, the researchers are investigating its potential efficacy as a topical antifungal.

“If a Candida infection breaks out on the skin of a patient where a catheter or other medical instrument is implanted, a topical antifungal might prevent the infection from spreading and entering into the body,” Marquez says.

As a next step, the researchers will test PGG as a topical treatment for fungal skin infections in mice.

Meanwhile, Quave and Marquez have applied for a provisional patent for the use of PGG for the mitigation of fungal infections.

“These are still early days in the research, but another idea that we’re interested in pursuing is the potential use of PGG as a broad-spectrum microbial,” Quave says. “Many infections from acute injuries, such as battlefield wounds, tend to be polymicrobial so PGG could perhaps make a useful topical treatment in these cases.”

Scientists from the University of Toronto are coauthors of the paper, including Yunjin Lee, Dustin Duncan, Luke Whitesell, and Leah Cowen. Whitesell and Cowen are co-founders and shareholders in Bright Angel Therapeutics, a platform company for development of antifungal therapeutics, and Cowen is a science advisor for Kapoose Creek, a company that harnesses the therapeutic potential of fungi.

The work had support from the National Institutes of Health; National Center for Complementary and Integrative Health; the Jones Center at Ichauway; the CIHR Frederick Banting and Charles Best Canada Graduate Scholarship; and the Canadian Institutes of Health Research Foundation.

Source: Emory University

The rate at which large cosmic structures grow is slower than Einstein’s Theory of General Relativity predicts, report researchers.

They also show that as dark energy accelerates the universe’s global expansion, the suppression of the cosmic structure growth that the researchers see in their data is even more prominent than what the theory predicts. Their results appear in Physical Review Letters.

As the universe evolves, scientists expect large cosmic structures to grow at a certain rate: dense regions such as galaxy clusters would grow denser, while the void of space would grow emptier.

Galaxies are threaded throughout our universe like a giant cosmic spider web. Their distribution is not random. Instead, they tend to cluster together. In fact, the whole cosmic web started out as tiny clumps of matter in the early universe, which gradually grew into individual galaxies, and eventually galaxy clusters and filaments.

“Throughout the cosmic time, an initially small clump of mass attracts and accumulates more and more matter from its local region through gravitational interaction. As the region becomes denser and denser, it eventually collapses under its own gravity,” says Minh Nguyen, lead author of the study and postdoctoral research fellow in the University of Michigan department of physics.

“So as they collapse, the clumps grow denser. That is what we mean by growth. It’s like a fabric loom where one-, two-, and three-dimensional collapses look like a sheet, a filament, and a node. The reality is a mixture of all three cases, and you have galaxies living along the filaments while galaxy clusters—groups of thousands of galaxies, the most massive objects in our universe bounded by gravity—sit at the nodes.”

The universe is not only made of matter. It also likely contains a mysterious component called dark energy. Dark energy accelerates the expansion of the universe on a global scale. As dark energy accelerates the expansion of the universe, it has the opposite effect on large structures.

“If gravity acts like an amplifier enhancing matter perturbations to grow into large-scale structure, then dark energy acts like an attenuator damping these perturbations and slowing the growth of structure,” Nguyen says. “By examining how cosmic structure has been clustering and growing, we can try to understand the nature of gravity and dark energy.”

Nguyen, physics professor Dragan Huterer, and graduate student Yuewei Wen examined the temporal growth of large-scale structure throughout cosmic time using several cosmological probes.

First, the team used what’s called the cosmic microwave background. The cosmic microwave background, or CMB, is composed of photons emitted just after the Big Bang. These photons provide a snapshot of the very early universe. As the photons travel to our telescopes, their path can become distorted, or gravitationally lensed, by large-scale structure along the way. Examining them, the researchers can infer how structure and matter between us and the cosmic microwave background are distributed.

Nguyen and colleagues took advantage of a similar phenomenon with weak gravitational lensing of galaxy shapes. Light from background galaxies is distorted through gravitational interactions with foreground matter and galaxies. The cosmologists then decode these distortions to determine how the intervening matter is distributed.

“Crucially, as the CMB and background galaxies are located at different distances from us and our telescopes, galaxy weak gravitational lensing typically probes matter distributions at a later time compared to what is probed by CMB weak gravitational lensing,” Nguyen says.

To track the growth of structure to an even later time, the researchers further used motions of galaxies in the local universe. As galaxies fall into the gravity wells of the underlying cosmic structures, their motions directly track structure growth.

“The difference in these growth rates that we have potentially discovered becomes more prominent as we approach the present day,” Nguyen says. “These different probes individually and collectively indicate a growth suppression. Either we are missing some systematic errors in each of these probes, or we are missing some new, late-time physics in our standard model.”

The findings potentially address the so-called S8 tension in cosmology. S8 is a parameter that describes the growth of structure. The tension arises when scientists use two different methods to determine the value of S8, and they do not agree. The first method, using photons from the cosmic microwave background, indicates a higher S8 value than the value inferred from galaxy weak gravitational lensing and galaxy clustering measurements.

Neither of these probes measures the growth of structure today. Instead, they probe structure at earlier times, then extrapolate those measurements to present time, assuming the standard model. Cosmic microwave background probes structure in the early universe, while galaxy weak gravitational lensing and clustering probe structure in the late universe.

The researchers’ findings of a late-time suppression of growth would bring the two S8 values into perfect agreement, according to Nguyen.

“We were surprised with the high statistical significance of the anomalous growth suppression,” Huterer says. “Honestly, I feel like the universe is trying to tell us something. It is now the job of us cosmologists to interpret these findings.

“We would like to further strengthen the statistical evidence for the growth suppression. We would also like to understand the answer to the more difficult question of why structures grow slower than expected in the standard model with dark matter and dark energy. The cause of this effect may be due to novel properties of dark energy and dark matter, or some other extension of General Relativity and the standard model that we have not yet thought of.”

Source: University of Michigan

New findings underscore the ways that being a Black mother in the United States involves navigating aspects of parenthood that are explicitly tied to dealing with anti-Black racism.

“All mothers experience stress; but Black mothers in the US experience additional stresses specifically related to parenting and racism,” says Mia Brantley, author of the study and an assistant professor of sociology at North Carolina State University. “That has consequences for the health and well-being of Black mothers. If we want to develop ways to support Black moms and Black families, we need to have a deeper understanding of the challenges facing Black mothers—and how Black mothers respond to those challenges.”

For this qualitative study, Brantley conducted in-depth interviews with 35 Black mothers from across the US. All of the study participants had at least one child between the ages of 10 and 24. The interviews were designed to collect information about how Black women think about motherhood and mothering, as well as how Black mothers feel race and racism influences both their parenting and the lives of their children.

“There is a broad understanding that motherhood is, while rewarding, also a demanding responsibility,” Brantley says. “This study found that, while Black mothers share many of the same concerns as other mothers, Black motherhood is distinct. That’s because—in addition to wanting their children to succeed—Black mothers also take steps to both protect their children from racism and help their children learn to navigate a society where they will experience anti-Black racism.”

Brantley categorizes the ways racism affects Black motherhood into three areas: protective mothering, resistance mothering, and encumbered mothering.

Protective mothering refers to practices designed to help Black children avoid racism. Specifically, Black mothers will often restrict children’s activities or behaviors in an attempt to reduce the likelihood that that their children—particularly sons—will face racist comments or actions. Black mothers also take steps to encourage agency—particularly for daughters—so that their children feel able to stand up for themselves.

• Resistance mothering refers to efforts to promote positive self-image, with the goal of combatting racist stereotypes their children encounter outside of the home. These activities might include educating children about Black artists, leaders, and accomplishments.
• “Resistance mothering is really about empowering Black children and parents, so that they take pride in themselves and their culture,” Brantley says.
• Encumbered mothering refers to the fact that Black mothers feel the need to be constantly hyperaware of the risks that racism poses to their children.

“Black mothers report that they are unable to fully enjoy and celebrate the accomplishments of their children, because they can’t ‘turn off’ their fears about how racist behavior may affect their kids,” Brantley says. “Black mothers feel that they always have to deal with preconceived notions about Black mothers and children, and that society essentially gives Black women no room for error.

“We talk about motherhood as universal, but all mothers do not experience motherhood in the same way,” Brantley says. “Black women face stresses that are unique to their experiences as mothers—stresses that continue into their children’s adulthood. While Black mothers are taking steps to protect their children, the stress of doing so may carry costs for the health and well-being of Black women.

“This study gives us a framework for understanding, studying, and talking about Black motherhood. And, hopefully, that gives us a starting point for a more in-depth analysis of the toll that motherhood takes on Black women, and how we—as a society—can do more to support these women.”

The study appears in the journal Social Problems. The work took place support from the National Institute on Aging, the Ohio State University Institute for Population Research, and a University of South Carolina SPARC grant.

Source: NC State

A new review paper suggests that scrambler therapy, a noninvasive pain treatment, can yield significant relief for approximately 80–90% of patients with chronic pain.

The paper also indicates that scrambler therapy may be more effective than another noninvasive therapy, transcutaneous electrical nerve stimulation, or TENS.

“It’s like pressing Control-Alt-Delete about a billion times.”

The researchers’ write-up appears in the New England Journal of Medicine.

Scrambler therapy, approved by the United States Food and Drug Administration in 2009, administers electrical stimulation through the skin via electrodes placed in areas of the body above and below where chronic pain is felt.

The goal is to capture the nerve endings and replace signals from the area experiencing pain with signals coming from adjacent areas experiencing no pain, thereby “scrambling” the pain signals sent to the brain, explains primary study author Thomas Smith, professor of palliative medicine at the Johns Hopkins Kimmel Cancer Center and a professor of oncology and medicine at the Johns Hopkins University School of Medicine.

All chronic pain and almost all nerve and neuropathic pain result from two things, says Smith, who also is the director of palliative medicine for Johns Hopkins Medicine:

• Pain impulses coming from damaged nerves that send a constant barrage up to pain centers in the brain.
• The failure of inhibitory cells to block those impulses and prevent them from becoming chronic.

“If you can block the ascending pain impulses and enhance the inhibitory system, you can potentially reset the brain so it doesn’t feel chronic pain nearly as badly,” Smith says. “It’s like pressing Control-Alt-Delete about a billion times.”

Many patients “get really substantial relief that can often be permanent,” he says. Treatment consists between three and 12 half-hour sessions.

As a physician who treats chronic pain, Smith says, “scrambler therapy is the most exciting development I have seen in years—it’s effective, it’s noninvasive, it reduces opioid use substantially, and it can be permanent.”

TENS therapy also administers low-intensity electrical signals through the skin, but it uses a pair of electrodes at the sites of pain. Pain relief often disappears when or soon after the electrical impulses are turned off, Smith says. A study cited in the review paper evaluated the impact of TENS in 381 randomized clinical trials, and the authors found a non-statistically significant difference in pain relief between TENS and a placebo procedure.

Source: Johns Hopkins University

Researchers have genetically engineered a marine microorganism to break down plastic in salt water, according to a new study.

Specifically, the modified organism can break down polyethylene terephthalate (PET), a plastic used in everything from water bottles to clothing that is a significant contributor to microplastic pollution in oceans.

“This is exciting because we need to address plastic pollution in marine environments,” says Nathan Crook, an assistant professor of chemical and biomolecular engineering at North Carolina State University and corresponding author of the paper published in AIChE Journal.

“One option is to pull the plastic out of the water and put it in a landfill, but that poses challenges of its own. It would be better if we could break these plastics down into products that can be re-used. For that to work, you need an inexpensive way to break the plastic down. Our work here is a big step in that direction.”

To address this challenge, the researchers worked with two species of bacteria. The first bacterium, Vibrio natriegens, thrives in saltwater and is remarkable, in part because it reproduces very quickly. The second bacterium, Ideonella sakaiensis, is remarkable because it produces enzymes that allow it to break down PET and eat it.

The researchers took the DNA from I. sakaiensis that is responsible for producing the enzymes that break down plastic, and incorporated that genetic sequence into a plasmid.

Plasmids are genetic sequences that can replicate in a cell, independent of the cell’s own chromosome. In other words, you can sneak a plasmid into a foreign cell, and that cell will carry out the instructions in the plasmid’s DNA. That’s exactly what the researchers did here.

By introducing the plasmid containing the I. sakaiensis genes into V. natriegens bacteria, the researchers were able to get V. natriegens to produce the desired enzymes on the surface of their cells. The researchers then demonstrated that V. natriegens was able to break down PET in a saltwater environment at room temperature.

“This is scientifically exciting because this is the first time anyone has reported successfully getting V. natriegens to express foreign enzymes on the surface of its cells,” Crook says.

“From a practical standpoint, this is also the first genetically engineered organism that we know of that is capable of breaking down PET microplastics in saltwater,” says Tianyu Li, a PhD student and the paper’s first author.

“That’s important, because it is not economically feasible to remove plastics from the ocean and rinse high concentration salts off before beginning any processes related to breaking the plastic down.”

“However, while this is an important first step, there are still three significant hurdles,” Crook says.

“First, we’d like to incorporate the DNA from I. sakaiensis directly into the genome of V. natriegens, which would make the production of plastic-degrading enzymes a more stable feature of the modified organisms. Second, we need to further modify V. natriegens so that it is capable of feeding on the byproducts it produces when it breaks down the PET. Lastly, we need to modify the V. natriegens to produce a desirable end product from the PET—such as a molecule that is a useful feedstock for the chemical industry.

“Honestly, that third challenge is the easiest of the three,” says Crook. “Breaking down the PET in saltwater was the most challenging part.

“We are also open to talking with industry groups to learn more about which molecules would be most desirable for us to engineer the V. natriegens into producing,” Crook says. “Given the range of molecules we can induce the bacteria to produce, and the potentially vast scale of production, which molecules could industry provide a market for?”

The National Science Foundation supported the work.

Source: NC State

A new molecularly engineered hydrogel that can create clean water using just the energy from sunlight.

The researchers were able to pull water out of the atmosphere and make it drinkable using solar energy, in conditions as low as 104 degrees, aligning with summer weather in Texas and other parts of the world.

That means people in places with excess heat and minimal access to clean water could someday simply place a device outside, and it would make water for them, with no additional effort necessary.

“With our new hydrogel, we’re not just pulling water out of thin air. We’re doing it extremely fast and without consuming too much energy,” says Guihua Yu, a materials science and engineering professor in the Cockrell School of Engineering’s Walker Department of Mechanical Engineering and Texas Materials Institute at the University of Texas at Austin.

“What’s really fascinating about our hydrogel is how it releases water. Think about a hot Texas summer—we could just use our temperatures’ natural ups and downs, no need to crank up any heaters.”

The device can produce between 3.5 and 7 kilograms (about 7.7 lbs to 15.4 lbs) of water per kilogram of gel materials, depending on humidity conditions.

A significant feature of this research is the hydrogel’s adaptability into microparticles called “microgels.” These microgels unlock the speed and efficiency improvements that bring this device much closer to reality.

“By transforming the hydrogel into micro-sized particles, we can make the water capture and release ultrafast,” says Weixin Guan, a graduate student in Yu’s lab and one of the lead authors of the study, published in the Proceedings of the National Academy of Sciences.

“This offers a new, highly efficient type of sorbents that can significantly enhance the water production by multiple daily cycling.”

The researchers are pursuing additional improvements to the technology, with an eye toward transforming it into a commercial product. One focus area is optimizing the engineering of the microgels to further improve efficiency.

Scaling up is an important next step. The researchers aim to translate their work into tangible and scalable solutions that can be used worldwide as a low-cost, portable method of creating clean drinking water. This could be life-changing for countries such as Ethiopia, where almost 60% of the population lacks basic access to clean water.

“We developed this device with the ultimate goal to be available to people around the world who need quick and consistent access to clean, drinkable water, particularly in those arid areas,” says Yaxuan Zhao, a graduate student in Yu’s lab.

The team is working on other versions of the device made from organic materials, which would reduce costs for mass production. This transition to more commercially viable designs comes with its own challenges in scaling production of the sorbent that allows moisture absorption and in maintaining durability for the product’s lifespan. Research is also focused on making the devices portable for various application scenarios.

The Norman Hackerman Award in Chemical Research from the Welch Foundation and the Camille Dreyfus Teacher-Scholar Award funded the work.

Source: UT Austin