Fivefold rise in young children swallowing magnets over past 5 years in UK

Nearly half of such cases required surgery for retrieval; surgical complication rate high

BMJ

Research News

 

There's been a fivefold rise in the number of young children requiring treatment after having swallowed a magnet over the past 5 years in the UK, suggests data from specialist doctors in a letter published online in the Archives of Disease in Childhood.

Nearly half of these children required surgery to remove the magnet, with surgical complications after retrieval a common occurrence.

Swallowing 'foreign bodies', such as coins and buttons, is common among young children from the age of 6 months onwards as they explore their environment, which is key to their development. Most of these objects pass out of the body naturally without causing any injury.

But this isn't always the case for button batteries and small neodymium magnets--strong permanent magnets found in cordless tools, hard disk drives, magnetic fasteners, and certain types of children's toy, highlight the authors from The Quadri-South East Paediatric Surgeons (QuadriSEPS) group.

This group comprises four tertiary children's surgical centres in the South East of England: Evelina London Children's Hospital, King's College Hospital, St George's University Hospitals, and the Royal Alexandra Children's Hospital.

Between January 2016 and December 2020, a total of 251 children were admitted to the four centres, after swallowing a foreign body, with a steady increase of 56% in admissions between the two time points.

Coins were the most common item swallowed (93; 37%), followed by magnets (52; 21%), and button batteries (42;17%).

The number of children who had swallowed a magnet increased fivefold between 2016 and 2020. Some 22 (42%) of those who had swallowed magnets required surgery for retrieval compared with just 1 (2.5%) of the button battery cases.

Ten out of 251 (4%) children experienced surgical complications after their procedure, with magnet retrieval accounting for 80% (8) of these cases, 4 of which were serious.

In the UK, there's a statutory requirement set out in the The Magnetic Toys (Safety) Regulations 2008, which requires all magnetic toys sold to be accompanied by a warning, but most manufacturers don't display these, point out the authors.

The age limit suitability on these toys is usually specified as 14 years and above, but the average age of the children who had swallowed magnets at the four centres was 7, ranging from 4 months to 16 years.

And while single magnets usually don't require removal, several swallowed magnets have the potential to wreak havoc in the gut, causing intestinal tissue death (necrosis) and perforation, they highlight.

"As a regional network of paediatric surgeons, we are extremely concerned with the recent rise in cases we have seen with foreign body ingestion and, in particular, magnets," write the authors.

"We recommend a strong public health campaign to increase awareness of the dangers of small, powerful magnets, especially those intended for toys, and to work with manufacturers in clearly warning purchasers of the dangers for children," they urge.

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Externally peer reviewed? Yes
Evidence type: Observational
Subjects: Children

Scientists will protect the "Smart City" from cyber threats

Researchers developed a methodology for analyzing cybersecurity risks

PETER THE GREAT SAINT-PETERSBURG POLYTECHNIC UNIVERSITY

Research News

 

IMAGE: RUSSIAN SCIENTISTS WILL PROTECT THE "SMART CITY " FROM CYBER THREATS view more 

CREDIT: PETER THE GREAT ST.PETERSBURG POLYTECHNIC UNIVERSITY

St. Petersburg, like other cities in the Russian Federation, is actively participating in the establishment of the "Smart City" program, which will provide new services for residents of the megalopolis, increasing the safety of citizens. Digital services are essential for such a system.

Due to the Internet of Things (IoT) systems, the environment can adapt to the needs of humanity on its own accord. Cybersecurity threats are especially dangerous for such infrastructure.

Specialists from Peter the Great St.Petersburg Polytechnic University (SPbPU) developed the methodology for assessing cyber risks in intelligent systems of a Smart City. The developed methodology was tested on the "smart crossroads" test bench (a component of the smart transport system of a Smart City). The results were published in the scientific journal "Machines" of the MDPI Publishing House.

Scientists note that the new goal for cybercriminals is to disrupt the functioning of large enterprises and urban infrastructure, as well as is to intercept the control over them. The attackers using wireless links can remotely invade into the target subnet or device (a group of devices), intercept traffic, launch denial of service attacks, and take control of IoT devices to create botnets.

"Currently, traditional cyber risk analysis strategies can't be directly applied in the construction and assessment of digital infrastructures in a Smart City, because the new network infrastructure is heterogeneous and dynamic. The goal of our project is to ensure the level of the information assets security considering the specifics of modern cyber threats," notes researcher Vasily Krundyshev, Institute of Cybersecurity and Data Protection SPbPU.

Researchers of St. Petersburg Polytechnic University developed a methodology for analyzing cybersecurity risks, which includes the stages of identifying asset types, identifying threats, calculating risks, and analyzing the resulting risk values. The proposed methodology is based on a quantitative approach, at the same time it is easily and quickly computable, which is especially important for the functioning of modern dynamic infrastructures. Experimental studies using a set of developed simulation models of typical digital infrastructures of a Smart City (Internet of Things, smart building, smart crossroads) demonstrated the superiority of the approach proposed by the authors over existing analogs.

In the near future, it is planned to arrange the automatic calculation of cybersecurity risks in a Smart City based on the developed methodology.

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The reported study was funded by Russian Foundation For Basic Research according to the research project #19-37-90001.

People are persuaded by social media messages, not view numbers

Study asked users to evaluate YouTube videos about e-cigarettes

OHIO STATE UNIVERSITY

Research News

 

COLUMBUS, Ohio - People are more persuaded by the actual messages contained in social media posts than they are by how many others viewed the posts, a new study suggests.

Researchers found that when people watched YouTube videos either for or against e-cigarette use, their level of persuasion wasn't directly affected by whether the video said it was viewed by more than a million people versus by fewer than 20.

What mattered for persuasion was viewers' perception of the message as truthful and believable.

"There wasn't a bandwagon effect in which people were persuaded by a video just because a lot of other people watched it," said Hyunyi Cho, lead author of the study and professor of communication at The Ohio State University.

"The message itself was most important for persuasion."

The study will appear in the June 2021 issue of the journal Media Psychology.

The study involved 819 demographically diverse American adults aged 18-35.

Most of them were shown two YouTube videos either for or against vaping. The pro-vaping videos were commercials for e-cigarette brands. The anti-vaping videos were public service announcements produced by anti-smoking nonprofit organizations.

The researchers, though, manipulated the view numbers that participants saw for the videos. Participants saw view numbers either around 10, 100, 100,000 or 1,000,000.

Participants rated how persuasive the videos were to them: whether they affected their curiosity about e-cigarettes, positive attitude toward e-cigarette use, and susceptibility to using e-cigarettes in the future.

Results showed that participants were more persuaded when they rated them as more truthful and believable. The number of views that the video had did not have a direct impact on how much they were persuaded.

Participants were also asked how much they thought the videos they watched would influence other young adults, Cho said.

Results showed that how participants themselves viewed the videos - whether they thought the videos were believable and truthful - was directly related to their estimation of the videos' impact on other people.

"People focused more on self-related factors - how they felt about the video - when considering how much influence it would have on others," Cho said.

"They concentrated less on other-focused factors - such as view numbers - as a reason why a video might be persuasive."

In addition, participants in the study didn't think that mass media would have as far of a reach as social media would.

Some participants saw the videos in a mock TV condition rather than in the YouTube condition. Overall, participants in the TV condition estimated the videos would have fewer views than did the participants in the YouTube condition.

"Social media may be seen as more pervasive than mass media like television because sites like YouTube do not have the same geographic boundaries as mass media may have," Cho said.

Overall, the results suggest that people should not equate popularity of YouTube videos and other social media posts with how many people find their messages persuasive or are persuaded by them, Cho said.

"We may choose to watch a YouTube video because it has a lot of views, but that is different from whether we are persuaded by the message," she said.

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The research was supported in part by the National Institutes of Health.

Contact: Hyunyi Cho, Cho.919@osu.edu

Written by Jeff Grabmeier, 614-292-8457; Grabmeier.1@osu.edu

Zoo YouTube videos prioritize entertainment over education

UNIVERSITY OF EXETER

Research News

 

YouTube channels run by zoos focus on entertainment over education, according to a new study.

The videos also focus disproportionately on mammals, rather than reflecting the diversity of zoos' animals.

Conservation was the focus of just 3% of zoo videos in the study - but it found that conservation content in videos is gradually increasing.

The study evaluated the most recent and most-viewed videos, so the findings partly reflect the public's preference for certain species and content.

Of the animals that appeared in zoos' most-viewed videos, the top nine were mammals - with giant pandas top of the list - and the only non-mammals were penguins in tenth place.

"They key question is: what are zoos using YouTube for?" said Dr Paul Rose, of the University of Exeter.

"If the aim is to get people to visit the zoo, then a focus on entertainment and popular species might make sense.

"This way, education about wildlife and conservation can be done once people get to the zoo, where they will spend much more time than they would watching a YouTube video.

"However, some zoos have large YouTube audiences, so they should carefully consider how they represent different classes of animal, and how they can create educational material in interesting and accessible forms.

"If an animal is in a zoo's collection, there should be a way for it to be promoted."

Dr Rose said he was encouraged to see an increased focus on conservation in zoo videos.

For example, videos about animals of conservation concern on the IUCN Red List have featured more often in recent years.

Lead author Thomas Llewellyn, a graduate from UWE's Science Communication Unit, said: "It is important that zoos produce a variety of conservation-focused content for a range of different animals.

"Whilst it is reassuring to see YouTube channels upload more conservation-focused videos in recent times, this research is especially important to the conservation projects associated with those 'favoured animals'.

"There is no doubt that YouTube has the potential to become an effective and efficient tool for global conservation education, but more research is needed to be done."

The study's information was gathered before the COVID pandemic, and the content posted on many zoo YouTube channels has changed dramatically since then.

"I've seen a lot more zoos doing live videos during lockdown to explain the significance of their animal collections," Dr Rose said.

"With zoo admissions essentially being non-existent this year, the pandemic has only emphasised the importance of social media for this type of online outreach", added Llewellyn.

The researchers evaluated the content of 1,000 videos from 20 zoological organisations (50 most-viewed videos from each channel) from 2006 to 2019. More than 75% of these videos focussed on mammals.

Separately, educational content in a subsample of 300 of the most viewed and most recent videos from three zoo YouTube channels was catalogued and evaluated for the period 2016 to 2019.

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The paper, published in the Journal of Zoological and Botanical Gardens, is entitled: "Education is entertainment? Zoo science communication on YouTube."

'Pre-bunk' tactics reduce public susceptibility to COVID-19 conspiracies and falsehoods

UNIVERSITY OF CAMBRIDGE

Research News

 

IMAGE: GO VIRAL! GAMEPLAY ON A PHONE SCREEN. view more 

CREDIT: UNIVERSITY OF CAMBRIDGE

A short online game designed to fight conspiracies about COVID-19 boosts people's confidence in detecting misinformation by increasing their ability to perceive its "manipulativeness" compared to genuine news, according to a study.

Go Viral!, developed by the University of Cambridge's Social Decision-Making Lab in partnership with the UK Cabinet Office and media agency DROG, was launched last autumn as part of the UK government's efforts to tackle coronavirus falsehoods circulating online.

The five-minute game puts people in the shoes of a purveyor of fake pandemic news, encouraging players to create panic by spreading misinformation about COVID-19 using social media - all within the confines of the game.

Researchers say that, by giving people this taste of the techniques used to disseminate fake news, it acts as an inoculant: building a psychological resistance against malicious falsehoods by raising awareness of how misinformation works.

"While fact-checking is vital work, it can come too late. Trying to debunk misinformation after it spreads is often a difficult if not impossible task," said Prof Sander van der Linden, Director of the Social Decision-Making Lab at Cambridge University.

"Go Viral! is part of a new wave of interventions that aim to 'pre-bunk'. By preemptively exposing people to a microdose of the methods used to disseminate fake news, we can help them identify and ignore it in the future."

The latest findings on the game's effectiveness, published in the journal Big Data and Society, are accompanied by research on another COVID-19 "prebunking" intervention used by the United Nations Educational, Scientific and Cultural Organization (UNESCO).

UNESCO deployed infographics across social media highlighting tropes common to COVID conspiracy theories, such as claims of a "secret plot" or that the virus was spread intentionally, as part of their #ThinkBeforeSharing campaign.

CAPTION

The Go Viral! start screen on a phone.

CREDIT

University of Cambridge

"By exposing people to the methods used to produce fake news we can help create a general 'inoculation', rather than trying to counter each specific falsehood," said study lead author and Cambridge Gates Scholar Melisa Basol.

The Cambridge researchers found the UNESCO approach also proved effective, albeit with a smaller effect size than the proactive game.

The Go Viral! project began with seed funding from Cambridge University's COVID-19 rapid response fund, and was then supported and backed by the UK Cabinet Office and promoted by the World Health Organisation and UN.

The game has now been played over 400,000 times in a variety of languages - including Italian, Spanish, Ukrainian, and Brazilian Portuguese - since its October launch.

Players try and gain "likes" by promoting noxious posts on COVID-19, harnessing propaganda techniques such as fraudulent expertise and the use of emotionally charged language to stoke outrage and fear.

The final stage sees players "go viral" when they push a baseless conspiracy theory that explodes online and ignites nationwide protests.

CAPTION

An example of one of the UNESCO infographics, part of their #ThinkBeforeSharing campaign, tested in the study.

CREDIT

UNESCO

For the new study, researchers used a sample of 3,548 players over the age of 18, including native speakers of three languages in which the game is available: English, German and French.

Study participants were shown 18 social media posts - nine containing information from credible news sources, and high-quality versions of COVID-19 conspiracies making up the rest - and asked the extent to which they felt manipulated by the framing and content of each one.

Roughly a third of the study participants then played Go Viral!, while another third - a control group - played Tetris for the same amount of time, and the final group read UNESCO's set of "prebunking" infographics. Lastly, everyone was given the same set of news items to rate, a mixture of real and fake.

Just over half (55%) the Tetris players got better at spotting the falsehoods, little better than chance - suggesting many were guessing.

However, 74% of the "pre-bunked" Go Viral! players got much better at sensing when they were being manipulated by the misinformation: a 19 percentage point increase over the control group.

The infographics generated a more modest but still useful six percentage point increase in manipulation detection compared to the control (61% vs 55%).

When it came to confidence in their ability to spot fake news going forward, only 50% of the Tetris players said it had increased - no better than chance - whereas 67% of Go Viral! players felt they were less likely to get duped in the future.

In a follow-up survey one week after the single play of the game, participants were asked to rate a further set of real and fake social media posts about COVID-19. Go Viral! players were still rating COVID-19 misinformation as significantly more manipulative, while the effects of the UNESCO infographics had faded.

"Both interventions are fast, effective and easily scalable, with the potential to reach millions of people around the world," said Dr Jon Roozenbeek, study co-lead author from Cambridge's Department of Psychology.

"Interestingly, our findings also show that the active inoculation of playing the game may have more longevity than passive inoculations such as reading the infographics."

"COVID-19 falsehoods and conspiracies pose a real threat to vaccination programmes in almost every nation. Every weapon in our arsenal should be used to fight the fake news that poses a threat to herd immunity. Pre-bunking initiatives have a crucial role to play in that global fight," Roozenbeek said.

Stefania Giannini, Assistant Director-General for Education at UNESCO, added: "Cambridge University has provided solid backing for 'pre-bunking' misinformation and conspiracy theories propagated and reinforced during the pandemic, which have real-life consequences undermining trust in science and fueling hate speech.

"In this context, UNESCO's work in education and media and information literacy is even more critical to strengthen learners' digital citizenship."

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Rooting the bacterial tree of life

UNIVERSITY OF QUEENSLAND

Research News

 

IMAGE: FUSOBACTERIA, GRACILICUTES AND BACTEROIDOTA ALL BRANCHED OFF FROM A LAST BACTERIAL COMMON ANCESTOR. view more 

CREDIT: THE UNIVERSITY OF QUEENSLAND

Scientists now better understand early bacterial evolution, thanks to new research featuring University of Queensland researchers.

Bacteria comprise a very diverse domain of single-celled organisms that are thought to have evolved from a common ancestor that lived more than three billion years ago.

Professor Phil Hugenholtz, from the Australian Centre for Ecogenomics in UQ's School of Chemistry and Molecular Biosciences, said the root of the bacterial tree, which would reveal the nature of the last common ancestor, is not agreed upon.

"There's great debate about the root of this bacterial tree of life and indeed whether bacterial evolution should even be described as a tree has been contested," Professor Hugenholtz said.

"This is in large part because genes are not just shared 'vertically' from parents to offspring, but also 'horizontally' between distant family members.

"We've all inherited certain traits from our parents, but imagine going to a family BBQ and suddenly inheriting your third cousin's red hair.

"As baffling as it sounds, that's exactly what happens in the bacterial world, as bacteria can frequently transfer and reconfigure genes horizontally across populations quite easily.

"This might be useful for bacteria but makes it challenging to reconstruct bacterial evolution."

For the bacterial world, many researchers have suggested throwing the 'tree of life' concept out the window and replacing it with a network that reflects horizontal movement of genes.

"However, by integrating vertical and horizontal gene transmission, we found that bacterial genes travel vertically most of the time - on average two-thirds of the time - suggesting that a tree is still an apt representation of bacterial evolution," Professor Hugenholtz said.

"The analysis also revealed that the root of the tree lies between two supergroups of bacteria, those with one cell membrane and those with two.

"Their common ancestor was already complex, predicted to have two membranes, the ability to swim, sense its environment, and defend itself against viruses."

The University of Bristol's Dr Tom Williams said this fact led to another big question.

"Given the common ancestor of all living bacteria already had two membranes, we now need to understand how did single-membrane cells evolve from double-membraned cells, and whether this occurred once or on multiple occasions," Dr Williams said.

"We believe that our approach to integrating vertical and horizontal gene transmission will answer these and many other open questions in evolutionary biology."

The research was a collaboration between UQ, the University of Bristol in the UK, Eötvös Loránd University in Hungary, and NIOZ in the Netherlands, and has been published in Science (DOI: 10.1126/science.abe5011).

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The Aqueduct of Constantinople: Managing the longest water channel of the ancient world

Double water channels may have been used to maintain the system while enabling constant operation

JOHANNES GUTENBERG UNIVERSITAET MAINZ

Research News

IMAGE: THE TWO-STORY KUR?UNLUGERME BRIDGE, PART OF THE AQUEDUCT SYSTEM OF CONSTANTINOPLE: TWO WATER CHANNELS PASSED OVER THIS BRIDGE - ONE ABOVE THE OTHER. view more 

CREDIT: PHOTO/©: JIM CROW

Aqueducts are very impressive examples of the art of construction in the Roman Empire. Even today, they still provide us with new insights into aesthetic, practical, and technical aspects of construction and use. Scientists at Johannes Gutenberg University Mainz (JGU) investigated the longest aqueduct of the time, the 426-kilometer-long Aqueduct of Valens supplying Constantinople, and revealed new insights into how this structure was maintained back in time. It appears that the channels had been cleaned of carbonate deposits just a few decades before the site was abandoned.

The late Roman aqueduct provided water for the population of Constantinople

The Roman Empire was ahead of its time in many ways, with a strong commitment to build infrastructure for its citizens which we still find fascinating today. This includes architecturally inspiring temples, theaters, and amphitheaters, but also a dense road network and impressive harbors and mines. "However, the most ground-breaking technical achievement of the Roman Empire lies in its water management, particularly its long-distance aqueducts that delivered water to cities, baths, and mines," said Dr. Gül Sürmelihindi from the Geoarchaeology group at Mainz University. Aqueducts were not a Roman invention, but in Roman hands these long-distance aqueducts developed further and extensively diffused throughout one of the largest empires in history.

Almost every city in the Roman Empire had an ample supply of fresh running water, in some cases actually with a larger volume than is the case today. "These aqueducts are mostly known for their impressive bridges, such as the Pont du Gard in southern France, which are still standing today after two millennia. But they are most impressive because of the way problems in their construction were solved, which would be daunting even for modern engineers," said JGU Professor Cees Passchier. More than 2,000 long-distance Roman aqueducts are known to date, and many more are awaiting discovery. The study undertaken by Dr. Gül Sürmelihindi and her research team focuses on the most spectacular late-Roman aqueduct, the water supply lines of Constantinople, now Istanbul in present-day Turkey.

Carbonate deposits provide insights into Byzantine water management

In AD 324, the Roman Emperor Constantine the Great made Constantinople the new capital of the Roman Empire. Although the city lies at the geopolitically important crossroads of land routes and seaways, fresh water supply was a problem. A new aqueduct was therefore built to supply Constantinople from springs 60 kilometers to the west. As the city grew, this system was expanded in the 5th century to springs that lie even 120 kilometers from the city in a straight line. This gave the aqueduct a total length of at least 426 kilometers, making it the longest of the ancient world. The aqueduct consisted of vaulted masonry channels large enough to walk through, built of stone and concrete, 90 large bridges, and many tunnels up to 5 kilometers long.

CAPTION

The 426-kilometer-long aqueduct system of Constantinople

CREDIT

ill./©: Cees Passchier

Sürmelihindi and her team studied carbonate deposits from this aqueduct, i.e., the limescale that formed in the running water, which can be used to obtain important information about water management and the palaeoenvironment at that time. The researchers found that the entire aqueduct system only contained thin carbonate deposits, representing about 27 years of use. From the annals of the city, however, it is known that the aqueduct system worked for more than 700 years, until at least the 12th century. "This means the entire aqueduct must have been maintained and cleaned of deposits during the Byzantine Empire, even shortly before it ceased working," explained Sürmelihindi. Carbonate deposits can block the entire water supply and have to be removed from time to time.

Double construction over 50 kilometers was likely built for maintenance

Although the aqueduct is late Roman in origin, the carbonate found in the channel is from the Byzantine Middle Ages. This made the researchers think about possible cleaning and maintenance strategies - because cleaning and repairing a channel of 426 kilometers implies that it cannot be used for weeks or months, while the city population depends on its water supply. They then found that 50 kilometers of the central part of the water system is constructed double, with one aqueduct channel above the other, crossing on two-story bridges. "It is very likely that this system was set up to allow for cleaning and maintenance operations," said Passchier. "It would have been a costly but practical solution."

Unfortunately for the research team, it is no longer possible to study the exact operation of the system. One of the most imposing bridges, that of Ballıgerme, was blown up with dynamite in 2020 by treasure hunters who erroneously believed they could find gold in the ruins.

CAPTION

The Ball?germe Bridge, part of the aqueduct system of Constantinople, which was destroyed by treasure hunters.

CREDIT

photo/©: Jim Crow

Images:

https://download.uni-mainz.de/presse/09_geowiss_tektonik_aquaedukt_valens_01.jpg

The 426-kilometer-long aqueduct system of Constantinople ill./©: Cees Passchier

https://download.uni-mainz.de/presse/09_geowiss_tektonik_aquaedukt_valens_02.jpg

The Ballıgerme Bridge, part of the aqueduct system of Constantinople, which was destroyed by treasure hunters. photo/©: Jim Crow

https://download.uni-mainz.de/presse/09_geowiss_tektonik_aquaedukt_valens_03.jpg

The two-story Kurşunlugerme Bridge, part of the aqueduct system of Constantinople: Two water channels passed over this bridge - one above the other. photo/©: Jim Crow

https://download.uni-mainz.de/presse/09_geowiss_tektonik_aquaedukt_valens_04.jpg

Carbonate deposit from the aqueduct system of Constantinople showing around 25 annual layers photo/©: Cees Passchier

https://download.uni-mainz.de/presse/09_geowiss_tektonik_aquaedukt_valens_05.jpg

Dr. Gül Sürmelihindi in the main water channel of the 426-kilometer-long aqueduct system of Constantinople photo/©: Cees Passchier

Related links:

https://www.geosciences.uni-mainz.de/tectonics-structural-geology-group/ - Tectonics and Structural Geology group at the JGU Institute of Geosciences ;

https://www.geosciences.uni-mainz.de/geoarchaeology/ - Geoarchaeology group at the JGU Institute of Geosciences

https://www.geosciences.uni-mainz.de/ - JGU Institute of Geosciences

Read more:

https://www.uni-mainz.de/presse/aktuell/12510_ENG_HTML.php - press release "The hydraulics of the world's first industrial plant: a unique construction in the Barbegal water mills" (13 Nov. 2020)

Pepsin-degradable plastics of bionylons from itaconic and amino acids

JAPAN ADVANCED INSTITUTE OF SCIENCE AND TECHNOLOGY

Research News

 

IMAGE: DEVELOPMENT STRATEGY FOR PEPSIN DEGRADABLE BIONYLONS FROM ITACONIC ACID AND LEUCINE. view more 

CREDIT: IMAGE COURTESY: TATSUO KANEKO AND MOHAMMAD ASIF ALI FROM JAPAN ADVANCED INSTITUTE OF SCIENCE AND TECHNOLOGY.

Point:

• Novel chiral diacid monomers were synthesized.
• Chirally interactive BioNylons were prepared.
• BioNylon showed thermal/mechanical performances than conventional Nylons.
• BioNylons disintegrated and degraded with pepsin.

Summary:

Marine plastic waste problems have been more serious year by year. One of the worst issues is that creatures in ocean are going extinct by mistakenly swallowing them.. Conventional biodegradable plastics are degradable in digestive enzymes, but their performances are too low to use in society. In this study, researchers from JAIST have used bio-derived resources such as itaconic acid and amino acid for the syntheses of high-performance BioNylons having the pepsin degradation function.

Ishikawa, Japan - Currently available conventional nylon such as Nylon 6, Nylon 66, and Nylon 11 are nondegradable. On the other hand, BioNylons derived from itaconic acid showed higher performances than conventional ones and degradability in soil, but degradability under the digestive enzymes was not confirmed.

To tackle these issues, a team of researchers from the Japan Advanced Institute of Science and Technologies (JAIST) are investigating syntheses of new BioNylons with their degradability under pepsin enzyme. Their latest study, published in Advanced Sustainable Systems-Wiley-VCH on April 2021, was led by Professor Tatsuo Kaneko and Dr. Mohammad Asif Ali.

In this study, BioNylons were synthesized based on chemically developed novel chiral dicarboxylic acids derived from renewable itaconic and amino acids (D- or L-leucine). Further, BioNylons were prepared via melt polycondensation of hexamethylenediamine with chirally interactive heterocyclic diacid monomers, as shown in Figure 1. The chiral interactions were derived from the diastereomeric mixture of the racemic pyrrolidone ring and the chiral amino acids of leucine. As a result, the polyamides showed a glass transition temperature, Tg, of approximately 117 °C and a melting temperature, Tm, of approximately 213 °C, which were higher than those of conventional BioNylon 11 (Tg of approximately 57 °C). The BioNylons also showed high Young's moduli, E, and mechanical strengths, σ, ranging from 2.2-3.8 GPa and 86-108 MPa, respectively. Such materials can be used for fishing nets, ropes, parachutes, and packaging materials, as a substitute for conventional nylons. The BioNylons including peptide linkage showed enzymatic degradation using pepsin, which is a digestive enzyme found in mammal stomach. The fact that pepsin-degradation can connect with biodegradation in the stomach of marine mammals. Such an innovative molecular design for high-performance nylons by controlling chirality can lead to establish a sustainable carbon negative society and energy conservation by weight saving.

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This research was carried out with the support of "Environment Research and Technology Development Fund (1-2005) of Environmental Restoration and Conservation Agency, ERCA. (Principal Investigator: Prof. Tatsuo Kaneko).

New marine sulfur cycle model after the Snowball Earth glaciation

SCIENCE CHINA PRESS

Research News

 

IMAGE: A COMPILATION OF PYRITE SULFUR ISOTOPE DATA SHOWING GLOBAL OCCURRENCES OF SUPERHEAVY PYRITE IN THE CRYOGENIAN INTERGLACIAL PERIOD. AFTER THE STURTIAN GLACIATION, MID-DEPTH SEAWATER COLUMN WAS SULFIDIC WHICH WAS SUSTAINED... view more 

CREDIT: ©SCIENCE CHINA PRESS

The Sturtian Snowball Earth glaciation (717~660 million years ago) represents the most severe icehouse climate in Earth's history. Geological evidence indicates that, during this glaciation, ice sheets extended to low latitudes, and model simulations suggest global frozen ocean as well as a prolonged shut-down of the hydrological cycles. The Snowball Earth hypothesis poses that the Sturtian global glaciation is directly triggered by intense continental weathering that scavenges atmospheric CO2, while the global frozen condition is terminated by extremely high atmospheric CO2 level (~350 times of present atmospheric level), which is accumulated by synglacial volcanic eruptions for tens of million years. The deglaciation is an abrupt process, lasting for hundreds to thousands of years, and the sharp transition to a hothouse condition is accompanied with extremely high weathering rate and followed by the perturbations of marine sulfur cycle.

Unusual perturbation of the marine sulfur cycle after the Sturtian glaciation is hinted at worldwide precipitation of isotopically superheavy sedimentary pyrite (FeS2) in the interglacial sediments. In the classic sulfur cycle framework, pyrite, the predominant sulfide mineral in sediments is always depleted in 34S as compared with seawater sulfate, because sulfate reducing microbes preferentially utilize 32S enriched sulfate to generate sulfide. However, a compilation of pyrite sulfur isotope data shows extremely high values (up to +70‰, obviously higher than coeval seawater sulfate values) in the aftermath of the Sturtian glaciation. Although superheavy pyrite is also reported in other geological periods, the Cryogenian interglacial interval after the Sturtian glaciation represents the only time with superheavy pyrite formation in a global scale for ~10 million years. The traditional theoretical sulfur cycle model does not satisfactorily address the long-term and global occurrence of superheavy pyrite in the Cryogenian interglacial interval.

Dr. Lang and his colleagues proposed a novel sulfur cycle model that incorporates volatile organosulfur compounds (VOSC) to interpret the global occurrence of superheavy pyrite after the Sturtian glaciation. They carried out detailed petrographic observations and paired pyrite content and sulfur isotope data of superheavy pyrite from the Cryogenian interglacial deposits of the Datangpo Formation in South China. Both the petrographic and geochemical data from South China indicate that the Cryogenian interglacial oceans were mainly sulfidic (anoxic and H2S enriched). In sulfidic conditions, volatile organosulfur compounds (VOSC) could be pervasively generated via sulfide methylation. Because the VOSC always has a lower sulfur isotope value relative to seawater sulfate, continuous VOSC emission would elevate sulfur isotope of residual sulfur pool of sulfidic seawater, resulting a vertical isotopic gradient of seawater and the precipitation of superheavy pyrite near/at seafloor.

Their findings demonstrate that superheavy pyrite formation requires both high microbial sulfate reduction and VOSC formation rates so as to maintain such unusual perturbation of marine sulfur cycle. As organic matter and sulfate are prerequisites for these reaction, ~10 million-year occurrences of superheavy pyrite may suggest continuous high primary productivity and intense continental chemical weathering after the Sturtian glaciation. These findings improve our understanding of the Snowball Earth event and ancient marine sulfur cycle.

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See the article:

Cracking the superheavy pyrite enigma: possible roles of volatile organosulfur compound emission. Lang et al. National Science Review, https://doi.org/10.1093/nsr/nwab034