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IMAGE: A MANATEE SWIMS BETWEEN THE SPANS OF THE MOBILE BAY BRIDGE IN LOWER ALABAMA. view more
CREDIT: DISL'S MANATEE SIGHTING NETWORK CONTRIBUTOR R. SYMES
A new publication from the Dauphin Island Sea Lab's Marine Mammal Research Program (DISL) examines how bridge-building and in-water construction activities may affect manatees and other large aquatic species. The article, which was recently published in The Journal of Wildlife Management, addresses the direct causes of injury and death and the longer-term, cumulative impacts on manatees and their habitats.
Some issues associated with construction activity include possible entanglement in barriers such as booms and siltation screens, loss of important habitats such as seagrass beds, and increased vessel activity near construction sites.
"Boat strikes are a major cause of manatee deaths, and increased presence of boats and barges in construction zones puts manatees at greater risk in these areas," stated lead author and manager of DISL's Manatee Sighting Network, Elizabeth Hieb. "Increased noise in construction areas can also mask the sound of approaching vessels, making it more difficult for manatees to avoid collisions," added Hieb.
DISL's new publication also reviews best practices to reduce the negative effects of construction on aquatic species. DISL researchers hope their work can be used to better understand and reduce the scope of risks associated with the construction of bridges, marinas, boat launches, and other infrastructure.
Manatees may be particularly vulnerable in areas along the northern Gulf of Mexico coast where less is known about their abundance and distribution. Data collected by DISL's Manatee Sighting Network since 2007 suggest that more manatees are seasonally migrating from Florida to Alabama and nearby waters in recent years. Construction projects planned in Mobile Bay, such as the expansion of the I-10 Bayway and deepening and widening of the Mobile Bay ship channel will benefit from the data and other information compiled in this timely review.
"This is not just an issue in Alabama or the U.S., but also globally," said Hieb. "More and more people are living in coastal areas where large species like manatees, dolphins, turtles, and fish also live, so manatees are a great model species for understanding how construction may affect many different species."
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You can help contribute data to DISL's Manatee Sighting Network by reporting manatee sightings at 1-866-493-5803 or online at http://www.
Beef industry can cut emissions with land management, production efficiency
Ranchers in United States, Brazil and other regions can help create a more climate-friendly beef system
IMAGE: RESEARCHERS FOUND THE MOST POTENTIAL FOR INDUSTRY TO REDUCE GREENHOUSE GAS EMISSIONS IN THE UNITED STATES AND BRAZIL. view more
CREDIT: KENTON ROWE FOR THE NATURE CONSERVANCY
A comprehensive assessment of 12 different strategies for reducing beef production emissions worldwide found that industry can reduce greenhouse gas (GHG) emissions by as much as 50% in certain regions, with the most potential in the United States and Brazil. The study, "Reducing Climate Impacts of Beef Production: A synthesis of life cycle assessments across management systems and global regions," is published April 5 in Global Change Biology.
A research team led by Colorado State University (CSU) and funded by the Climate and Land Use Alliance found that widespread use of improved ranching management practices in two distinct areas of beef production would lead to substantial emissions reductions. This includes increased efficiency to produce more beef per unit of GHG emitted - growing bigger cows at a faster rate - and enhanced land management strategies to increase soil and plant carbon sequestration on grazed lands.
Globally, cattle produce about 78% of total livestock GHG emissions. Yet, there are many known management solutions that, if adopted broadly, can reduce, but not totally eliminate, the beef industry's climate change footprint, according to lead author Daniela Cusack, an assistant professor in the Department of Ecosystem Science and Sustainability at CSU.
Overall, the research team found a 46% reduction in net GHG emissions per unit of beef was achieved at sites using carbon sequestration management strategies on grazed lands, including using organic soil amendments and restoring trees and perennial vegetation to areas of degraded forests, woodlands and riverbanks. Additionally, researchers found an overall 8% reduction in net GHGs was achieved at sites using growth efficiency strategies. Net-zero emissions, however, were only achieved in 2% of studies.
"Our analysis shows that we can improve the efficiency and sustainability of beef production, which would significantly reduce the industry's climate impact," said Cusack, also a research associate at the Smithsonian Tropical Research Institute in Panama. "But at the same time, we will never reach net-zero emissions without further innovation and strategies beyond land management and increased growth efficiency. There's a lot of room, globally, for improvement."
Global analysis
Researchers analyzed 292 comparisons of "improved" versus "conventional" beef production systems across Asia, Australia, Brazil, Canada, Latin America and the U.S. The analysis revealed that Brazilian beef production holds the most potential for emissions reductions.
In the studies analyzed, researchers found a 57% GHG emission reduction through improved management strategies for both carbon sequestration and production efficiency in Brazil. Specific strategies include improved feed quality, better breed selections and enhanced fertilizer management.
The biggest impact was found in integrated field management, including intensive rotational grazing schemes, adding soil compost, reforestation of degraded areas and selectively planting forage plants bred for sequestering carbon in soils.
"My home country of Brazil has more than 52 million hectares of degraded pastureland - larger than the state of California," said Amanda Cordeiro, co-author and a graduate student at CSU. "If we can aim for a large-scale regeneration of degraded pastures, implementation of silvo-agro-forestry systems and adoption of other diversified local management strategies to cattle production, Brazil can drastically decrease carbon emissions."
In the U.S., researchers found that carbon sequestration strategies such as integrated field management and intensive rotational grazing reduced beef GHG emissions by more than 100% - or net-zero emissions - in a few grazing systems. But efficiency strategies were not as successful in the U.S. studies, possibly because of a high use of the strategies in the region already.
"Our research shows the important role that ranchers can play in combatting the global climate crisis, while ensuring their livelihoods and way of life," said Clare Kazanski, co-author and North America region scientist with The Nature Conservancy. "By analyzing management strategies in the U.S. and around the world, our research reinforces that ranchers are in a key position to reduce emissions in beef production through various management strategies tailored to their local conditions."
Darrell Wood, a northern California rancher, is an example of a producer leading the way on climate-friendly practices. Wood's family participates in the California Healthy Soils program, which incentivizes practices with a demonstrated climate benefit.
"As a sixth-generation cattle rancher, I see nothing but upside potential from using our cattle as a tool for reducing greenhouse gas emissions," Wood said. "Taking good care of our grasslands not only benefits climate, but also wildlife and the whole ecosystem that generates clean air and water. It'll help the next generation continue our business, too."
Next steps
Although the research shows a significant reduction in the GHG footprints of beef production using improved management strategies, scientists don't yet know the full potential of shifting to these emission-reducing practices because there are very few data on practice adoption levels around the world.
"Asia, for example, is one of the most rapidly growing beef markets, but there is an imbalance between the amount of research focus on improving beef production and the growing demand for beef," Cusack said. "We know with the right land management and efficiency strategies in place, it's possible to have large reductions in emissions across geographic regions, but we need to keep pushing for additional innovations to create a truly transformation shift in the way the global beef system operates to ensure a secure food supply and a healthy environment."
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Additional co-authors on the paper include Alexandra Hedgpeth, Kenyon Chow and Jason Karpman (University of California, Los Angeles); and Rebecca Ryals (University of California, Merced).
Piping plovers breed less and move more in the northern great plains
Species may show higher extinction risk than currently presumed
IMAGE: TWO BANDED PIPING PLOVER ADULTS STAND NEAR A NEST WITH A SMALL VIDEO CAMERA POINTED AT IT ON A SANDBAR ON THE GARRISON REACH OF THE MISSOURI RIVER, NORTH DAKOTA.... view more
CREDIT: USGS
Piping plover breeding groups in the Northern Great Plains are notably connected through movements between habitats and show lower reproductive rates than previously thought, according to a new U.S. Geological Survey study. These new findings point to a need for further studies and suggest the species may show a higher extinction risk than currently presumed.
Piping plovers are small-bodied, short-distance migratory shorebirds. The Northern Great Plains population has been listed as a threatened species under the U.S. Endangered Species Act since 1985. Previously, wildlife managers had assumed four separate breeding groups within the Northern Great Plains and that individuals from these groups moved infrequently between habitats. Earlier studies based on this assumption resulted in a low extinction risk for the species.
Scientists analyzed movement, survival and renesting rates in two of the assumed breeding groups of piping plovers over four distinct management units along the Missouri River and alkaline wetlands distributed throughout the prairie pothole region from 2014 - 2019. Piping plover reproductive rates were studied between 2014 - 2016. The study areas are within North Dakota, South Dakota and Montana and include the U.S. alkali wetlands, Lake Sakakawea, the Garrison Reach of the Missouri River, and Lake Oahe.
Results show river and alkali wetland habitats appear to be of higher quality than reservoir habitats, which had lower annual survival, increased movement away from the habitat, lower renesting success, and lower reproductive output.
Habitat availability affected nearly every parameter examined in this study. In general, when more habitat was available, piping plover vital rates improved. These findings support the current focus of managing the Missouri River for abundant breeding habitat for piping plovers.
Study findings show managing for successful first nests for Northern Great Plains piping plovers is key to improving reproductive output. Piping plovers are intensively managed throughout their range, and in the Northern Great Plains, management of habitat, water and predation, including vegetation removal and protective fences around nests, are common conservation strategies. Therefore, intensive management focused on the protection of early nests or first nest attempts would likely be more effective than strategies that assume equivalent productivity from renests.
The study also shows that piping plovers move between the northern Missouri River habitat and the U.S. alkali wetlands at a rate that is substantially higher than previously assumed. Further, movement rates were unbalanced and varied between hatch-year and adult plovers. Adults were more likely to forego breeding altogether than to relocate to alternate management units and breed. This implies that either the rates of movement or the way local bird populations are managed may need to be reevaluated.
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This study was done in cooperation with U.S. Army Corps of Engineers and U.S. Fish and Wildlife Service. For more information on USGS ecosystems research in the Prairie Pothole Region, please visit the USGS Northern Prairie Wildlife Research Center website.
Tech transfer - Fueling retooling
In a new twist to an existing award-winning ORNL technology, researchers have developed an electrocatalyst that enables water and carbon dioxide to be split and the atoms recombined to form higher weight hydrocarbons for gasoline, diesel and jet fuel.
The technology is a carbon nanospike catalyst that uses nanoparticles of a custom-designed alloy, which has been licensed by California-based Prometheus Fuels. The spiky textured surface of the catalysts provides ample reactive sites to facilitate the carbon dioxide-to-hydrocarbons conversion.
"This cutting-edge catalyst will enable us to further lower the price of our zero net carbon fuels," said Rob McGinnis, CEO and founder of Prometheus.
The company plans to use the technology in its process for converting electricity from solar and wind into chemical energy to make zero net carbon electrofuels.
The carbon nanospike catalyst was invented using a one-of-a-kind nanofabrication instrument and staff expertise at ORNL's Center for Nanophase Materials Sciences.
Media contact: Karen Dunlap, 865.696.5910, dunlapkk@ornl.gov
Image: https:/
Caption: ORNL researchers have developed an electrocatalyst made of custom-designed alloy nanoparticles embedded in carbon nanospikes. This image, made with a transmission electron microscope, shows the carbon nanospikes. Credit: Adam Rondinone and Dale Hensley/ORNL, U.S. Dept. of Energy
Transportation - Keep on truckin'
A newly released dataset that tracks the movement of everything from food to gasoline across the United States by air, water, truck, rail and pipeline showed the value and tonnage of those goods rose significantly between 2012 and 2017.
The Freight Analysis Framework, or FAF, is the most comprehensive public database of freight movement in the country, compiled by Oak Ridge National Laboratory and released every five years by the U.S. Department of Transportation.
The recent release, FAF5, revealed that 20 billion tons of U.S. goods valued at nearly $19 trillion were moved in 2017 compared with 17 billion tons valued at about $18 trillion in 2012. Trucks consistently transport about 64% of that freight.
"We help DOT build a comprehensive picture of where and how goods traveled and what commodities are being moved. The goal is to provide federal and state planners with critical data to inform infrastructure investment decisions," said ORNL's Ho-Ling Hwang.
Media contact: Stephanie Seay, 865.576.9894, seaysg@ornl.gov
Image: https:/
Caption: Public and private planners can use a FAF5 online tool to create maps to visualize the flow of goods into and across the U.S., for example, when making critical transportation infrastructure and equipment decisions. Credit: Hyeonsup Lim, ORNL/U.S. Dept. of Energy
Buildings - Concrete on the double
A team of researchers at Oak Ridge National Laboratory and the University of Tennessee have developed a concrete mix that demonstrated high early strength within six hours of mixing, potentially doubling the production capacity for the precast industry.
Quick performing concrete shortens manufacturing time for prefabricated assemblies such as walls, beams and floor slabs. However, early-strength mixes have short setting times and require specific curing methods.
In a study, researchers evaluated commercially available components including steel, glass and carbon fibers. The result was a self-compacting mix that not only showed early strength but also maintained its workability for 30 minutes.
"We followed a practical, cost-effective process easily implemented with typical mixing procedures," ORNL's Diana Hun said. "This could enable precast plants to cast twice per day."
Future research includes decreasing the amount of carbon embodied in the mix. The study was conducted in collaboration with the Precast/Prestressed Concrete Institute.
Media contact: Jennifer Burke, 865.414.6835, burkejj@ornl.gov
Image: https:/
Caption: ORNL researchers used fiber reinforcements made of steel, glass and carbon to develop a concrete mix that demonstrated high early strength within six hours of production, which is needed for the precast concrete industry. Credit: ORNL/U.S. Dept. of Energy
Image: https:/
Caption: Researchers from ORNL and the University of Tennessee collaborated to perform lab-scale evaluations on the high early strength fiber-reinforced self-compacting concrete mix. Credit: University of Tennessee
Recycling - A batteries passport
Scientists at Oak Ridge National Laboratory have devised a method to identify the unique chemical makeup of every lithium-ion battery around the world, information that could accelerate recycling, recover critical materials and resolve a growing waste stream.
Similar to how plastics are stamped with a recycling code identifying their makeup, Li-ion batteries could be encoded with what ORNL researchers described as a Battery Identity Global Passport, which could be accessible as a scannable QR code or a computer chip. This method could help recyclers more efficiently locate in-demand materials and accommodate the wide variety of designs used to manufacture Li-ion batteries.
"This passport can help recyclers contend with the mixed stream of materials since there's no standard cell chemistry now for Li-ion battery production," said ORNL's Ilias Belharouak. "The challenge is growing as we see more of these batteries used in electric vehicles, for energy storage and in electronic devices."
Media contact: Stephanie Seay, 865.576.9894, seaysg@ornl.gov
Image: https:/
Caption: The proposed Battery Identity Global Passport suggests a scannable QR code or other digital tag affixed to Li-ion batteries to identify materials for efficient end-of-life recycling. Credit: Andy Sproles, ORNL/U.S. Dept. of Energy
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IMAGE: CARBONACEOUS CHONDRITE AND DIFFERENT MOLECULAR COMPOSITIONS DISTRIBUTIONS IN IT view more
CREDIT: SKOLTECH
Scientists from Russia and Germany studied the molecular composition of carbonaceous chondrites - the insoluble organic matter of the Murchison and Allende meteorites - in an attempt to identify their origin. Ultra-high resolution mass spectrometry revealed a wide diversity of chemical compositions and unexpected similarities between meteorites from different groups. The research was published in the Scientific Reports.
Carbonaceous chondrites contain nearly the entire spectrum of organic molecules encountered on Earth, including nucleic acids which might have played a pivotal role in the origin of life. Since the majority of modern meteorites are of nearly the same age as the Earth, their composition should be similar to that of meteorites that bombarded the Earth's surface in ancient times. Just like comets, they can be considered a source of organic compounds which most likely formed the core of the Earth's biosphere.
According to Skoltech Senior Research Scientist Alexander Zherebker, "the geological history of the Earth is a continuous process that involves division and transformation (biological or otherwise) of the Solar System's primary matter. What remains of that matter ends up on Earth in the form of chondrites. However, two centuries of research on the organic matter of meteorites fall short of a full picture of its molecular composition: for instance, there is no systematic data on insoluble organic matter of meteorites which may account for up to 70% of all organic carbon in the samples. Presumably, these substances have much higher molecular complexity than suggested by research focusing on particular classes of organic compounds."
Scientists from Skoltech, Moscow State University, Vernadsky Institute of Geochemistry and Analytical Chemistry of RAS, and the Rostock Institute (Germany) applied ultra-high resolution mass spectrometry methods to study the composition of meteorites. The Skoltech team included researchers from the Mass Spectrometry Laboratory at the Skoltech Center for Computational and Data-Intensive Science and Engineering (CDISE): Alexander Zherebker, Yury Kostyukevich, Alexey Kononikhin, and Oleg Kharybin. The research was led by Skoltech Professor Evgeny Nikolaev, Corresponding Member of RAS, Doctor of Physics and Mathematics, Head of the Mass Spectrometry Laboratory.
The team discovered an amazing molecular diversity in the insoluble organic matter of carbonaceous chondrites. "Considering that meteorites and the Earth are of similar age, we can argue that the organic matter of carbonaceous chondrites could have been the source of chemical compounds which served as building blocks for biological molecules and life on Earth. However, meteorite composition has nothing to do with living matter, which is evidenced, for example, by totally different oxidative profiles of extraterrestrial organic matter and a similar fraction of coal of biological origin. That is to say, meteorites showed no signs of "selection" of compounds," Alexander Zherebker comments.
The analysis of carbonaceous chondrite extracts by isotopic exchange mass spectrometry revealed the presence of sulfur-containing compounds with all possible oxidation states from -2 to +6, which was in no way related to the sample's thermal history, as previously thought. The relative content of these compounds was the only difference, as confirmed by the Murchison and Allende samples.
The team's findings suggest that the precursors which created different celestial bodies produced similar organic matter which later transformed in various ways, depending on the environment and its various effects.
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Skoltech is a private international university located in Russia. Established in 2011 in collaboration with the Massachusetts Institute of Technology (MIT), Skoltech is cultivating a new generation of leaders in the fields of science, technology, and business is conducting research in breakthrough fields and is promoting technological innovation with the goal of solving critical problems that face Russia and the world. Skoltech is focusing on six priority areas: data science and artificial intelligence, life sciences, advanced materials and modern design methods, energy efficiency, photonics, and quantum technologies, and advanced research. Web: https:/
Rise of oxygen on Earth: Initial estimates off by 100 million years
Permanent oxygenation occurred much later than previously thought
IMAGE: RESEARCH TEAM LEADER SPRAYS WATER ON DRILL CORES TO SEE SEDIMENTARY ROCKS AND SELECT SAMPLES FOR THIS STUDY. view more
CREDIT: ANDREY BEKKER/UCR
New research shows the permanent rise of oxygen in our atmosphere, which set the stage for life as we know it, happened 100 million years later than previously thought.
A significant rise in oxygen occurred about 2.43 billion years ago, marking the start of the Great Oxidation Episode -- a pivotal moment in Earth's history.
An international research team including a UC Riverside scientist analyzed rocks from South Africa formed during this event. Findings, published this week in the journal Nature, include the discovery that oxygen fluctuated dramatically after its early appearance until it became a permanent constituent of the atmosphere much later.
These fluctuations reinforce a direct link between atmospheric oxygen and concentrations of greenhouse gases such as methane, helping to explain some of the most extreme climate changes in the planet's past.
During the same period, ancient Earth experienced four glaciations -- periods when the whole planet was covered with ice and snow for millions of years. According to UC Riverside geologist Andrey Bekker, changes in atmospheric oxygen levels began and ended these events.
Scientists have often wondered how the planet could have emerged from the periods in which ice and snow covered everything, including the oceans. According to Bekker, increases in atmospheric oxygen levels resulted in low concentrations of greenhouse gases, such as methane and carbon dioxide. This ushered in global glaciations by maintaining surface conditions below the water-freezing temperature.
Volcanoes also continued to erupt on the frozen planet, building required high levels of carbon dioxide in the atmosphere to exit from climatic catastrophe by warming the planet and melting the snow and ice.
"Before this work, we all wondered why the fourth glacial event happened if oxygen was already a steady component in the atmosphere," Becker said. "We found it was not steady. The permanent rise of oxygen actually occurred after the fourth, final glaciation in the Paleoproterozoc Era, and not before it, and this solves what had previously been a major puzzle in our understanding."
The Great Oxidation Episode ushered in a 1.5 billion-year period of subsequent environmental stability, which lasted until a second major transitional period, marked by rising atmospheric oxygen and similar climatic changes at the end of the Precambrian time.
"We thought once oxygen increased it wouldn't ever return back to lower levels," Bekker said. "Now we have learned it fluctuated to very low levels and this could have dramatic implications in terms of understanding extinction events and the evolution of life."
Open questions include the reasons for these multiple fluctuations, and whether complex life could have evolved and then died out again in response to them, said Simon Poulton, a biogeochemist at Leeds University who led the research.
"We cannot begin to understand the causes and consequences of atmospheric oxygenation, the most significant control on Earth's habitability, if we do not know when permanent atmospheric oxygenation actually occurred," he said. "Now at last we have that piece of the puzzle."
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THE ANWSER IS INTERNATIONALISM
'Vaccine Nationalism' is a threat to equitable access and herd immunity
WHAT While the U.S. has begun to vaccinate millions of Americans each day, COVID-19 vaccine supplies around the world remain scarce. Experts estimate that 80 percent of people in low-resource countries will not receive a vaccine in 2021. At the time of the paper's writing, the global vaccination rate was 6.7 million doses per day -- a rate at which it would take 4.6 years to achieve global herd immunity. In a new Perspective piece in the New England Journal of Medicine, Katz and colleagues highlight the need to treat essential medical services as public goods, rather than market commodities. To truly protect U.S. residents and their neighbors, they urge the federal government to reinforce global vaccine distribution efforts.
"The early competitive procurement of vaccines by the United States and purchases by other high-resource countries have fed a widespread assumption that each country will be solely responsible for its own population," the authors write. "Such vaccine nationalism perpetuates the long history of powerful countries securing vaccines and therapeutics at the expense of less-wealthy countries; it is short-sighted, ineffective, and deadly."
Through the COVID-19 Vaccines Global Access (COVAX) program, the U.S. and the G7 nations have committed to vaccinating at least 20 percent of the populations of participating low- and middle-income countries by the end of 2021. But this falls far below the broader goal of achieving herd immunity by vaccinating at least 70 to 85 percent of the population and substantially increases the likelihood that new viral variants will emerge.
Drawing upon lessons learned from the HIV pandemic, when most low-resource countries could not access lifesaving therapies, the authors argue that the government should invest in what some experts are calling the President's Emergency Plan for Vaccine Access and Relief (PEPVAR), a spin-off of the 2003 President's Emergency Plan for AIDS Relief (PEPFAR). This latter plan was founded to deliver antiretroviral therapies globally, and a program like PEPVAR could draw upon pre-existing strategies to scale up the delivery of vaccines beyond COVAX's commitments. Like the plan for AIDS relief, it could leverage partnerships with governmental and multilateral organizations to improve vaccine access. Equally important is ensuring vaccine supply, and the authors posit that the World Trade Organization may be justified in temporarily waiving pharmaceutical patent protections to substantially reduce the costs of manufacturing vaccines.
"The United States has an unusual and urgent opportunity to ensure that COVID-19 vaccines are available to all," the authors write. "By investing in multilateral partnerships with a sense of shared commitment and employing a global allocation strategy that increases supply and manufacturing, we can meet the urgent challenge of COVID-19, while creating sustainable infrastructures and health systems for the future."
Marxist Summer School - The Internationale : Free Download, Borrow, and Streaming : Internet Archive
Making cleaner, greener plastics from waste fish parts
IMAGE: USING FISH OIL, RESEARCHERS HAVE MADE A POLYURETHANE-LIKE MATERIAL. view more
CREDIT: MIKHAILEY WHEELER
WASHINGTON, April 5, 2021 -- Polyurethanes, a type of plastic, are nearly everywhere -- in shoes, clothes, refrigerators and construction materials. But these highly versatile materials can have a major downside. Derived from crude oil, toxic to synthesize, and slow to break down, conventional polyurethanes are not environmentally friendly. Today, researchers discuss devising what they say should be a safer, biodegradable alternative derived from fish waste -- heads, bones, skin and guts -- that would otherwise likely be discarded.
The researchers will present their results today at the spring meeting of the American Chemical Society (ACS). ACS Spring 2021 is being held online April 5-30. Live sessions will be hosted April 5-16, and on-demand and networking content will continue through April 30. The meeting features nearly 9,000 presentations on a wide range of science topics.
If developed successfully, a fish-oil based polyurethane could help meet the immense need for more sustainable plastics, says Francesca Kerton, Ph.D., the project's principal investigator. "It is important that we start designing plastics with an end-of-life plan, whether it's chemical degradation that turns the material into carbon dioxide and water, or recycling and repurposing."
To make the new material, Kerton's team started out with oil extracted from the remains of Atlantic salmon, after the fish were prepared for sale to consumers. "I find it interesting how we can make something useful, something that could even change the way plastics are made, from the garbage that people just throw out," says Mikhailey Wheeler, a graduate student who is presenting the work at the meeting. Both Kerton and Wheeler are at Memorial University of Newfoundland (Canada).
The conventional method for producing polyurethanes presents a number of environmental and safety problems. It requires crude oil, a non-renewable resource, and phosgene, a colorless and highly toxic gas. The synthesis generates isocyanates, potent respiratory irritants, and the final product does not readily break down in the environment. The limited biodegradation that does occur can release carcinogenic compounds. Meanwhile, demand for greener alternatives is growing. Previously, others have developed new polyurethanes using plant-derived oils to replace petroleum. However, these too come with a drawback: The crops, often soybeans, that produce the oil require land that could otherwise be used to grow food.
Leftover fish struck Kerton as a promising alternative. Salmon farming is a major industry for coastal Newfoundland, where her university is located. After the fish are processed, leftover parts are often discarded, but sometimes oil is extracted from them. Kerton and her colleagues developed a process for converting this fish oil into a polyurethane-like polymer. First, they add oxygen to the unsaturated oil in a controlled way to form epoxides, molecules similar to those in epoxy resin. After reacting these epoxides with carbon dioxide, they link the resulting molecules together with nitrogen-containing amines to form the new material.
But does the plastic smell fishy? "When we start the process with the fish oil, there is a faint kind of fish smell, but as we go through the steps, that smell disappears," Kerton says.
Kerton and her team described this method in a paper last August, and since then, Wheeler has been tweaking it. She has recently had some success swapping out the amine for amino acids, which simplifies the chemistry involved. And while the amine they used previously had to be derived from cashew nut shells, the amino acids already exist in nature. Wheeler's preliminary results suggest that histidine and asparagine could fill in for the amine by linking together the polymer's components.
In other experiments, they have begun examining how readily the new material would likely break down once its useful life is over. Wheeler soaked pieces of it in water, and to speed up the degradation for some pieces, she added lipase, an enzyme capable of breaking down fats like those in the fish oil. Under a microscope, she later saw microbial growth on all of the samples, even those that had been in plain water, an encouraging sign that the new material might biodegrade readily, Wheeler says.
Kerton and Wheeler plan to continue testing the effects of using an amino acid in the synthesis and studying how amenable the material is to the microbial growth that could hasten its breakdown. They also intend to study its physical properties to see how it might potentially be used in real world applications, such as in packaging or fibers for clothing.
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A press conference on this topic will be held Thursday, April 8, at 11 a.m. Eastern time online at http://www.
The researchers acknowledge support and funding from the Natural Sciences and Engineering Research Council of Canada and Memorial University of Newfoundland.
IMAGE: BALTIC AMBER IS NOT ONLY BEAUTIFUL, BUT ALSO A POTENTIAL SOURCE OF NEW ANTIBIOTICS. view more
CREDIT: CONNOR MCDERMOTT
WASHINGTON, April 5, 2021 -- For centuries, people in Baltic nations have used ancient amber for medicinal purposes. Even today, infants are given amber necklaces that they chew to relieve teething pain, and people put pulverized amber in elixirs and ointments for its purported anti-inflammatory and anti-infective properties. Now, scientists have pinpointed compounds that help explain Baltic amber's therapeutic effects and that could lead to new medicines to combat antibiotic-resistant infections.
The researchers will present their results today at the spring meeting of the American Chemical Society (ACS). ACS Spring 2021 is being held online April 5-30. Live sessions will be hosted April 5-16, and on-demand and networking content will continue through April 30. The meeting features nearly 9,000 presentations on a wide range of science topics.
Each year in the U.S., at least 2.8 million people get antibiotic-resistant infections, leading to 35,000 deaths, according to the U.S. Centers for Disease Control and Prevention. "We knew from previous research that there were substances in Baltic amber that might lead to new antibiotics, but they had not been systematically explored," says Elizabeth Ambrose, Ph.D., who is the principal investigator of the project. "We have now extracted and identified several compounds in Baltic amber that show activity against gram-positive, antibiotic-resistant bacteria."
Ambrose's interest originally stemmed from her Baltic heritage. While visiting family in Lithuania, she collected amber samples and heard stories about their medicinal uses. The Baltic Sea region contains the world's largest deposit of the material, which is fossilized resin formed about 44 million years ago. The resin oozed from now-extinct pines in the Sciadopityaceae family and acted as a defense against microorganisms such as bacteria and fungi, as well as herbivorous insects that would become trapped in the resin.
Ambrose and graduate student Connor McDermott, who are at the University of Minnesota, analyzed commercially available Baltic amber samples, in addition to some that Ambrose had collected. "One major challenge was preparing a homogeneous fine powder from the amber pebbles that could be extracted with solvents," McDermott explains. He used a tabletop jar rolling mill, in which the jar is filled with ceramic beads and amber pebbles and rotated on its side. Through trial and error, he determined the correct ratio of beads to pebbles to yield a semi-fine powder. Then, using various combinations of solvents and techniques, he filtered, concentrated and analyzed the amber powder extracts by gas chromatography-mass spectrometry (GC-MS).
Dozens of compounds were identified from the GC-MS spectra. The most interesting were abietic acid, dehydroabietic acid and palustric acid -- 20-carbon, three-ringed organic compounds with known biological activity. Because these compounds are difficult to purify, the researchers bought pure samples and sent them to a company that tested their activity against nine bacterial species, some of which are known to be antibiotic resistant.
"The most important finding is that these compounds are active against gram-positive bacteria, such as certain Staphylococcus aureus strains, but not gram-negative bacteria," McDermott says. Gram-positive bacteria have a less complex cell wall than gram-negative bacteria. "This implies that the composition of the bacterial membrane is important for the activity of the compounds," he says. McDermott also obtained a Japanese umbrella pine, the closest living species to the trees that produced the resin that became Baltic amber. He extracted resin from the needles and stem and identified sclarene, a molecule present in the extracts that could theoretically undergo chemical transformations to produce the bioactive compounds the researchers found in Baltic amber samples.
"We are excited to move forward with these results," Ambrose says. "Abietic acids and their derivatives are potentially an untapped source of new medicines, especially for treating infections caused by gram-positive bacteria, which are increasingly becoming resistant to known antibiotics."
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A press conference on this topic will be held Monday, April 5, at 11 a.m. Eastern time online at http://www.
The researchers acknowledge support and funding from the University of Minnesota Engebretson Drug Design and Development Grant and the Office of the Vice President for Research Grant-in-Aid of Research, Artistry, and Scholarship Program.
