A new process with zero emissions for truly biodegradable plastics

The European project PROMICON issues five policy recommendations to support a new method for the production of sustainable bioplastics from microorganisms

Pensoft Publishers

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PROMICON policy brief

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Credit: PROMICON project

Petrol-based plastics are present in many aspects of our daily lives, from clothing to food packaging. They are often left behind in the environment, where they degrade, breaking into thousands of tiny pieces that harm ecosystems and human health. While biodegradable plastics are seen as a potential solution, their production remains limited, accounting for just 1.3 million tons in 2022 compared to 400 million tons of petrol-based plastics. Many biodegradable plastics also fail to biodegrade efficiently under all environmental conditions such as soil, rivers, and oceans.

In this context, researchers from the Horizon 2020 project PROMICON have developed an innovative method that leverages photosynthetic microorganisms (cyanobacteria) to produce polyhydroxyalkanoates (PHA) – a type of bioplastic that fully degrades in soil, water, and marine environments. PHA is naturally produced by microorganisms, but scaling up its production remains a challenge:

 ‘Commercially produced PHA is nowadays highly energy-intensive and relies heavily on organic raw materials and clean water, which conflicts with the EU’s goals for a circular, sustainable economy. The current production process is far away from the zero emissions neutral carbon strategy.’

– explain the authors of PROMICON’s policy brief. 

The new approach for PHA production proposed by researchers from the Polytechnic University of Catalonia uses sunlight, absorbs CO2, and requires minimal organic resources, creating a truly biodegradable plastic alternative that leaves no microplastic residues.

Find out more about the new method for PHA production here. 

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This project receives funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 101000733. Views and opinions expressed are those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Executive Agency (REA). Neither the EU nor REA can be held responsible for them.

 

Study sheds light on how to encourage condom use among teens

North Carolina State University

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A new meta-analysis evaluating condom use across 249 studies and more than a quarter million U.S. teens finds that simply having knowledge about safer sex practices is not enough to encourage condom use. The analysis suggests teens also need to feel confident about buying and using condoms, they need to plan to use them, and they need to be able to communicate effectively with their partners about condom use.

“Condoms are effective at preventing pregnancy and protecting against sexually transmitted infections, but only about half of sexually active teens in the U.S. used a condom the last time they had sex,” says Laura Widman, corresponding author of the meta-analysis and a professor of psychology at North Carolina State University. “Our goal with this work was to figure out exactly what predicts condom use among teens.

“This is important because sexually transmitted infections are on the rise among teens, and this study will help us understand which aspects of sexual health decision-making should be targeted in sex education programs. For example, our analysis really underscores the importance of effective communication between partners about condom use, which tells us that future programs should prioritize developing this skill set in teens.”

For this meta-analysis, the researchers drew on data from 249 studies published between 2000 and 2024. Collectively, those studies involved 251,713 study participants with a mean age of just over 16. The researchers synthesized the data from those studies using statistical techniques to examine 36 different predictors of condom use. The researchers then conducted a series of analyses designed to identify factors that were most closely associated with condom use.

“We found that having knowledge about safe sex, by itself, was not correlated with condom use across studies,” Widman says. “We know that just giving people knowledge alone is not enough to change their behavior.”

However, the researchers did identify several factors that are associated with condom use.

“Teens who used a condom the first time they had sex were far more likely to use condoms consistently over time,” Widman says. “This underscores the importance of early interventions, before teens have their first sexual experiences.”

Other notable predictors were whether teens planned to use condoms prior to having sex, whether teens were communicating with their partners about condom use, and teens’ confidence in their ability to engage in safer sex. The researchers found that all of these predictors held true across age, gender and sexual orientation.

“This meta-analysis combines more than 20 years of research to help us better understand how teens make decisions in sexual relationships,” Widman says. “The findings highlight the need to boost teens’ interpersonal skills and confidence, and to do so early in their development so they can make the best sexual choices for themselves.”

The paper, “Identifying the Strongest Correlates of Condom Use Among U.S. Adolescents: a Systematic Review and Meta-Analysis,” is published in the journal JAMA Pediatrics. The paper was co-authored by NC State Ph.D. students Jordyn McCrimmon and Aaron Lankster; Julia Brasieiro, a postdoctoral researcher at Florida State University and a Ph.D. graduate of NC State; Reina Evans-Paulson of Innovation Research and Training; Anne Maheux of the University of North Carolina at Chapel Hill; and Claire Stout and Sophia Choukas-Bradley of the University of Pittsburgh.

This research was done with support from the Eunice Kennedy Shriver National Institute of Child Health & Human Development under grant R03 HD105784; the National Institutes of Health under grants F31 MH126763 and F31 HD114366; and the National Science Foundation under grants 1940700 and 2139321.

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Journal

JAMA Pediatrics

DOI

10.1001/jamapediatrics.2024.5594 

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

Identifying the Strongest Correlates of Condom Use Among US Adolescents

Article Publication Date

27-Jan-2025

 

Young people support the idea of a smokefree generation, according to a new study

University of Nottingham

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Young people broadly welcome the idea of the Government’s smokefree generation policy and see it as a chance to free their generation from harmful addiction, according to a study led by the University of Nottingham.

Smoking tobacco kills more people than any other preventable cause. The UK Government are aiming for fewer than five in 100 people to smoke by 2030, however, one study estimates 127,500 people aged between 18 and 25 currently pick up smoking each year.

The Tobacco and Vapes Bill Committee reports on Thursday 30 January and the Bill will return to the House of Commons for debate and final vote among MPs in the coming months.

If passed, the Bill will stop children who turned 15 last year or younger from ever legally being sold cigarettes or other tobacco products.

A new study, published in Nicotine & Tobacco Research led by Nathan Davies, from the Nottingham Centre for Public Health and Epidemiology, and funded by the National Institute for Health and Care Research (NIHR), set out to find out what young people in England think about changing the law on how old you must be to buy tobacco and e-cigarettes.

Mr Davies said: “Nearly all smokers start smoking when they are young, so if we can prevent people from starting in their youth, they are unlikely to begin in later life. Little was known about what young people think about the proposed smokefree generation policy we wanted to find out if they agreed with it in principle and its implementation.”

 

The researchers held focus groups with participants aged between 12 and 21.  Participants were chosen to include those from areas of different areas and for use of tobacco or e-cigarettes.

The focus groups showed that:

• There was broad support for the smokefree generation. Most young participants welcomed the idea of preventing future tobacco addiction, seeing it as a chance to free their generation from harmful, entrenched habits. Young people had first-hand experience of the harm of tobacco; one 13-year-old girl said, “We were really worried about my mum’s smoking. She said that she was going to try and stop, but she really hasn’t. And it must be difficult because it’s not something that she really talks to us much about.”
•  A small minority raised concerns about freedom of choice or showed apathy towards the policy.
• Young people called for strong enforcement. They believed that the policy’s success depends on strict penalties for retailers selling to underage buyers. They felt that, without well-resourced enforcement of offending retailers, the law wouldn’t be as effective or wouldn’t work at all. Many also asked for licensing conditions to be introduced for tobacco retailers.
• Participants asked for a say in shaping and communicating the policy. They believed involving young people from the start ensures messaging resonates and helps politicians understand real-world tactics used to evade age restrictions. A 17-year-old boy said, ““I think youth involvement is really good and important idea because it’s important that young people feel they are the smokefree generation”.

 

“The study conversations show it is really important that young people are involved in the design and implementation of the smokefree generation,” said Mr Davies. “It is reassuring that the general feeling was support for the policy. Young people want the smokefree generation done properly – and that means the Government giving Trading Standards the resources to enforce it from day one.”

Hazel Cheeseman, Chief Executive of Action on Smoking and Health (ASH), said, “These interviews reinforce survey results which find strong support for the phased-out sale of tobacco among those who the policy will impact. MPs who are anxious that they are curbing the choices of future generations should recognise that ending the sale of tobacco is freeing young people from the risk of life-long addiction and chronic illness. The next generation sees this legislation as a gift not a burden and want to be part of creating a smokefree future for all.”

The full results of the study can be found here.

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Journal

Nicotine & Tobacco Research

DOI

10.1093/ntr/ntae300 

Method of Research

Survey

Subject of Research

People

Article Title

Perceptions of Children and Young People in England on the Smokefree Generation Policy: A Focus Group Study

 

Finding the most efficient carbon-neutral aircraft for your flight

Sustainable aviation doesn't have a one-size-fits-all solution, but an interactive tool can identify the right fit given the flight distance, speed and payload

University of MichiganFacebook

 

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OK, we admit, we're a long way from a carbon-free grid—but when we have one, what's the most efficient way to use that energy to fly planes? This question is explored by an interactive tool built by a team of University of Michigan researchers.

"Aircraft provide a fantastic means to transport people and goods anywhere in the world within a day. We want to keep this capability, but with a lower climate impact," said Joaquim Martins, the Pauline M. Sherman Collegiate Professor of Aerospace Engineering at U-M and co-author of the study published in Progress in Aerospace Sciences.

Sustainable aviation doesn't have a silver bullet, but it does have a bunch of options. Battery-powered motors would be most efficient if it weren't for the weight of the batteries: 85% of the electricity makes it to the aircraft. 

Unfortunately, weight is a big deal. Extra weight demands more lift—the force that holds an aircraft in the air. More lift creates more drag, which demands more thrust, which requires more battery power, which adds weight, and pretty soon the battery is taking up the entire weight formerly allocated to cargo or passengers. As a result, battery power is really best for short hops—metro to regional journeys.

The tool lets users see this and also game out different scenarios. For each combination of range and speed, the researchers pinpointed the least energy-hungry option from four sustainable propulsion systems: e-SAF (synthetic jet fuel produced with carbon captured from the air), battery-electric, hydrogen fuel cell and hydrogen combustion. 

"The tool provides a strategy for thinking about what sustainable aviation should look like. It's not an ultimate answer, but a means to compare and evolve these ideas further," said Eytan Adler, a recent doctoral graduate of aerospace engineering at U-M and first author of the study.

The team defined efficiency as the amount of renewable electricity required to generate the fuel that propels an aircraft on a specified mission, which accounts for both sustainability and cost. Currently, fuel makes up 25%-30% of airlines' operating costs and can even edge up to 40% for flights that cross the Atlantic or Pacific oceans.

Of the fuels, e-SAF is the most compatible with existing aircraft. The synthetic fuel would replace jet fuel, negating the CO2 released in flight with the CO2 captured from the air during synthesis. Battery-electric aircraft work just like electric cars, using batteries to power an electric motor, but require different aircraft designs to accommodate batteries.

The two hydrogen propulsion systems differ from one another in the way that hydrogen reacts with oxygen from the air. Fuel cells produce electricity, which powers an electric motor. Combustion produces heat, which drives a turbine. While hydrogen fuel cells do not produce nitrogen oxides—a major contributor to air pollution—and may be more efficient than hydrogen combustion engines in some cases, they are heavier.

To assess the propulsion systems, the research team developed a methodology to rapidly estimate aircraft energy consumption for a given mission. It incorporates currently available or soon-to-be available technologies, and users can adjust sliders to find out how changes in key properties of these technologies change which aircraft is best for a given flight.

It answers questions like what if the battery could store more energy for the same weight? What if we could store more hydrogen without increasing the weight of the tank? What if fuel cells were more efficient? And it also addresses properties of the propeller, motor, fan and more.

While batteries are limited to about 100 miles with current technology, they could be good for up to 800 miles or so if the "Batt 1K" target of 1000 watt hours per kilogram is reached.

For longer haul flights, hydrogen fuel is the most efficient. Although producing hydrogen with electricity is half as efficient as sending that electricity straight to a battery-electric aircraft, liquid hydrogen is two orders of magnitude lighter—even considering the weight of the tank. Of the two hydrogen propulsion options, combustion uses renewable electricity most efficiently for faster flights over about 300 knots. Fuel cells are best for slower flights because they are more efficient than small combustion engines.

Since e-SAF requires a large amount of energy to produce, only 26% of the electricity makes it to the aircraft in the form of fuel. This prevents the synthetic fuel from outcompeting hydrogen or battery options with the given technology assumptions.

Study: Energy demand comparison for carbon-neutral flight (DOI: 10.1016/j.paerosci.2024.101051)

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Journal

Progress in Aerospace Sciences

DOI

10.1016/j.paerosci.2024.101051 

Remote sensing tools yield insights into abandoned pre-Columbian Mexican city

Awareness of the Zapotecs’ level of political and social organization stands to shed light on their level of agency in negotiating with the Spanish

McGill University

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Serpent sculpture from the serpent plaza found by an earlier archaeological expedition and now in the Oaxacan hall in the National Museum of Anthropology in Mexico City.

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Credit: Pedro Guillermo Ramón Celis

A McGill University researcher has discovered that Guiengola, a 15th century Zapotec site in southern Oaxaca, Mexico, which had been thought to be simply a fortress where soldiers were garrisoned, was in fact a sprawling, fortified city. It covered 360 hectares, with over 1,100 buildings, four kilometres of walls, a network of internal roads and a clearly organized urban layout with temples and communal spaces such as ballcourts, and the elites and commoners lived in separate neighbourhoods.

According to Pedro Guillermo Ramón Celis, a Banting postdoctoral researcher in McGill’s Department of Anthropology and the author of a recent article in Ancient Mesoamerica, the evidence strongly suggests the city was abandoned just before the Spanish arrived, and that its people moved just 20 kilometres away to Tehuantepec, a small city where their descendants still live today.

Ramón Celis said investigating how the Mesoamerican city was organized on the eve of the Spanish conquest is just the first step. He said he is convinced that as work on Guiengola advances, it will give researchers a better sense of the Zapotecs’ level of political and social organization, and thus a greater understanding of their level of agency in negotiating with the Spanish.

The finding was made by using a remote sensing tool known as lidar (light detection and ranging). Lidar relies on pulsing laser beams, in a process akin to sonar, to provide precise, detailed, three-dimensional topographic information about what is on the earth’s surface, below the dense forest canopy.

“My mother’s family is from the region of Tehuantepec which is about 15 km from the site, and I remember them talking about it when I was a child. It was one of the reasons that I chose to go into archaeology,” Ramón Celis said. “Although you could reach the site using a footpath, it was covered by a canopy of trees. Until very recently, there would have been no way for anyone to discover the full extent of the site without spending years on the ground walking and searching. We were able to do it within two hours by using remote sensing equipment and scanning from a plane.”

By analyzing the data generated by the scans and using the Geo Analytic laboratory at McGill, Ramón Celis has been able to map the size and the layouts of the remaining built structures and infer their use based on the artifacts found at the locations.

To explore how power was distributed in the city, he has calculated how much building space was given over to elite areas such as the temples and ballcourts, for example, compared to what was built in the areas used by commoners. Ballcourts were built in Mesoamerica for the purpose of practicing a ritual ballgame, and represent both the underworld and fertility, since they are a way of connecting with the ancestors and seeds grow below the soil, where the underworld is found.

Ramón Celis added, “Because the city is only between 500 and 600 years old, it is amazingly well preserved, so you can walk there in the jungle, and you find that houses are still standing… you can see the doors… the hallways… the fences that split it from other houses. So, it is easy to identify a residential lot. It's like a city frozen in time, before any of the deep cultural transformations brough by the Spanish arrival had taken place.”

 

The research: “Airborne lidar at Guiengola, Oacaxa: Mapping a Late Postclassic Zapotec city” by Pedro Guillermo Ramón Celis was published in Ancient Mesoamerica

DOI: https://doi.org/10.1017/S0956536124000166

The funding: Wenner-Gren Foundation, Indiana University College of Arts and Sciences and now the Canadian Social Sciences and Humanities Research Council.

Public and Private spaces in Guiengola 

North of the centre of the site it is possible to observe public spaces, such as the North Plaza, and private elite spaces, such as the Ballcourt No.2

Credit

Pedro Guillermo Ramón Celis

View of Guiengola’s North Plaza from above, the only area not covered by the tree canopy

Credit

Pedro Guillermo Ramón Celis

Lidar scan showing the Civic and Ceremonial Center (left) and the commoner areas (right), split by a defensive wall (centre)

Credit

Pedro Guillermo Ramón Celis

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Journal

Ancient Mesoamerica

DOI

10.1017/S0956536124000166 

Article Title

Airborne lidar at Guiengola, Oacaxa: Mapping a Late Postclassic Zapotec city

 

Turning farm waste into sustainable roads

Xianming Shi, civil and architectural engineering department chair at the University of Miami, was awarded a grant from the U.S. Department of Agriculture to research how to turn farming byproducts into sustainable asphalt.

University of Miami

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A typical road is made of rocks and sand held together by petroleum to create the smooth surfaces we drive on every day. But some of these materials come at a cost: during the production and installation of asphalt, harmful emissions are released, posing health risks to workers and communities.

Now, researchers led by Xianming Shi, chair of the civil and architectural engineering department at the University of Miami College of Engineering, are exploring a cleaner, greener alternative. With a $1 million grant from the U.S. Department of Agriculture, the team is studying how agricultural waste can be converted into biochar to build roadways. The three-year project aims to revolutionize the transportation industry by reducing reliance on petroleum-based materials and providing a carbon-neutral alternative for infrastructure development.

“This is an exciting opportunity, as this is likely the very first solution to truly move asphalt pavement toward net-zero — that is, carbon neutrality,” Shi said. “In addition, we can clearly observe fewer toxic fumes being emitted from asphalt pavement during production.”

At the heart of the project is biochar, a CO2-negative material produced by heating organic waste, such as orchard trimmings, wheat straw, and poultry litter, in a low-oxygen environment through a process known as pyrolysis. The approach not only repurposes millions of tons of agricultural byproducts and waste generated annually on farms across the country but also turns them into a material that can sequester carbon in asphalt pavement while potentially extending the lifespan of roads.

Millions of tons of organic waste at farms are often discarded or left to decompose, releasing methane and other harmful gases into the atmosphere. By converting this waste into biochar (and bio-oil) and using high doses of reclaimed asphalt pavement, Shi and his team aim to sequester large amounts of carbon in the asphalt pavement itself. The project could also create economic opportunities for farmers and poultry producers by diverting farm waste toward better uses.

Turning Waste Into a Revenue Stream

The research team is multidisciplinary, including three economists to analyze how the technology can help local communities.

“This project goes beyond engineers working together to decarbonize asphalt,” Shi said. “This is a bold approach that will essentially create a new market and green jobs; that is why we also consider the socioeconomic dimensions of this innovation.”

Shi, along with researchers from California State University-Chico, Washington State University, and the University of Georgia, also plans to partner with two tribal communities to test the biochar-enhanced asphalt on local paving projects, showcasing the material’s real-world potential.

A Vision for Climate-Driven Engineering

Shi’s leadership has brought a renewed focus on environmental sustainability, with infrastructure decarbonization and coastal resilience at the core of the department’s mission.

“We are transforming into a climate infrastructure engineering department,” Shi said. “We have faculty doing exciting research on the decarbonization of the built environment—whether it’s roads, bridges, tunnels, ports, or buildings—especially looking at how we can reduce their carbon footprint. Being in Miami, it makes sense to also focus on coastal resilience, with internationally known innovations like the SEAHIVE for coastal defense.”