Awareness of SARS-CoV-2 omicron variant infection among adults

JAMA Network Open

Peer-Reviewed Publication

JAMA NETWORK

About The Study: The results of this study in Los Angeles County of 210 adults with recent Omicron variant infection suggest that more than half were unaware of their infectious status and that awareness was higher among health care employees than nonemployees, yet it was still low overall. Unawareness may be a key contributor to rapid transmission of the virus within communities.

Authors: Susan Cheng, M.D., M.P.H., of Cedars-Sinai Medical Center in Los Angeles, is the corresponding author.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/ 

(doi:10.1001/jamanetworkopen.2022.27241)

Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.

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About JAMA Network Open: JAMA Network Open is the new online-only open access general medical journal from the JAMA Network. On weekdays, the journal publishes peer-reviewed clinical research and commentary in more than 40 medical and health subject areas. Every article is free online from the day of publication.

Study: Most people infected

With Omicron didn’t know it

Cedars-Sinai researchers find 56% were unaware they were infected with virus that causes COVID-19

Peer-Reviewed Publication

CEDARS-SINAI MEDICAL CENTER

The majority of people who were likely infected with the Omicron variant of SARS-CoV-2, the virus that causes COVID-19, didn’t know they had the virus, according to a new study from Cedars-Sinai investigators. The findings are published in JAMA Network Open.

“More than one in every two people who were infected with Omicron didn’t know they had it,” said Susan Cheng, MD, MPH, director of the Institute for Research on Healthy Aging in the Department of Cardiology at the Smidt Heart Institute at Cedars-Sinai and corresponding author of the study. “Awareness will be key for allowing us to move beyond this pandemic.” 

Prior studies have estimated that at least 25% and possibly as many as 80% of people infected with SARS-CoV-2 may not experience symptoms. Compared to other SARS-CoV-2 variants, the Omicron variant is associated with generally less severe symptoms that may include fatigue, cough, headache, sore throat or a runny nose.

“Our study findings add to evidence that undiagnosed infections can increase transmission of the virus,” said Sandy Y. Joung, MHDS, an investigator at Cedars-Sinai and first author of the study. “A low level of infection awareness has likely contributed to the fast spread of Omicron.”

As part of research into the effects of COVID-19 and the impact of vaccines, the investigators began collecting blood samples from healthcare workers more than two years ago. In the fall of 2021, just before the start of the omicron variant surge, the investigators were able to expand enrollment to include patients, thanks to study infrastructure and biospecimen processing support provided by Sapient Bioanalytics. 

Of the healthcare workers and patients who have participated in the research, investigators identified 2,479 people who had contributed blood samples just prior to or after the start of the Omicron surge. The investigators identified 210 people who likely were infected with the Omicron variant based on newly positive levels of antibodies to SARS-CoV-2 in their blood. 

Next, the investigators invited study participants to provide health status updates through surveys and interviews. Only 44% of study participants with newly positive SARS-CoV-2 antibodies had awareness of being infected with the virus. The majority (56%) were unaware of any recent COVID-19 infection. Of the study participants who were unaware, only 10% reported having any recent symptoms that they attributed to a common cold or other type of infection. 

More studies involving larger numbers of people from diverse ethnicities and communities are needed to learn what specific factors are associated with a lack of infection awareness, according to the investigators.

“We hope people will read these findings and think, ‘I was just at a gathering where someone tested positive,’ or, ‘I just started to feel a little under the weather. Maybe I should get a quick test.’ The better we understand our own risks, the better we will be at protecting the health of the public as well as ourselves,” said Cheng, the Erika J. Glazer Chair in Women's Cardiovascular Health and Population Science at Cedars-Sinai.

Cheng and colleagues are also studying patterns and predictors of reinfections and their potential to offer long-lasting immunity to SARS-CoV-2. In addition to raising awareness, this information could help people manage their individual risk.

Other Cedars-Sinai investigators who worked on this study include Joseph E. Ebinger, MD; Nancy Sun, MPS; Yunxian Liu, PhD; Min Wu, MPH, and Kimia Sobhani, PhD.

Learn more about this ongoing COVID-19 study here.

Funding: The study was funded by the Erika J. Glazer Family Foundation and Sapient Bioanalytics LLC. 

Disclosures: Kimia Sobhani, PhD, has served as a consultant for Abbott Diagnostics and Sapient Bioanalytics, a company that supported the collection and processing of samples for this study. 

 

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JOURNAL

JAMA Network Open

GOOD NEWS

Scientists relieved to discover ‘curious’ creature with no anus is not earliest human ancestor

Peer-Reviewed Publication

UNIVERSITY OF BRISTOL

 

IMAGE: SACCORHYTUS view more 

CREDIT: PHILIP DONOGHUE ET AL

An international team of researchers have discovered that a mysterious microscopic creature from which humans were thought to descend is part of a different family tree.

Resembling an angry Minion, the Saccorhytus  is a spikey, wrinkly sack, with a large mouth surrounded by spines and holes that were interpreted as pores for gills – a primitive feature of the deuterostome group, from which our own deep ancestors emerged.

However, extensive analysis of 500 million year old fossils from China has shown that the holes around the mouth are bases of spines that broke away during the preservation of the fossils, finally revealing the evolutionary affinity of the microfossil Saccorhytus.

“Some of the fossils are so perfectly preserved that they look almost alive,” says Yunhuan Liu, professor in Palaeobiology at Chang’an University, Xi’an, China. “Saccorhytus was a curious beast, with a mouth but no anus, and rings of complex spines around its mouth.”

The findings, published today in Nature, make important amendments to the early phylogenetic tree and the understanding of how life developed.

The true story of Saccorhytus’ ancestry lies in the microscopic internal and external features of this tiny fossil. By taking hundreds of X-ray images at slightly different angles, with the help of powerful computers, a detailed 3D digital model of the fossil could be reconstructed. Researcher Emily Carlisle from the University of Bristol’s School of Earth Sciences explained: “Fossils can be quite difficult to interpret and Saccorhytus is no exception. We had to use a synchrotron, a type of particle accelerator, as the basis for our analysis of the fossils. The synchrotron provides very intense X-Rays that can be used to take detailed images of the fossils. We took hundreds of X-Ray images at slightly different angles and used a supercomputer to create a 3D digital model of the fossils, which reveals the tiny features of its internal and external structures.”

The digital models showed that pores around the mouth were closed by another body layer extending through, creating spines around the mouth. “We believe these would have helped Saccorhytus capture and process its prey,” suggests Huaqiao Zhang from the Nanjing Institute of Geology and Palaeontology.

The researchers believe that Saccorhytus is in fact an ecdysoszoan: a group that contains arthropods and nematodes. “We considered lots of alternative groups that Saccorhytus might be related to, including the corals, anemones and jellyfish which also have a mouth but no anus,” said Prof Philip Donoghue of University of Bristol’s School of Earth Sciences, who co-led the study. “To resolve the problem our computational analysis compared the anatomy of Saccorhytus with all other living groups of animals, concluding a relationship with the arthropods and their kin, the group to which insects, crabs and roundworms belong.”

Saccorhytus’ lack of anus is an intriguing feature of this microscopic, ancient organism. Although the question that springs to mind is the alternative route of digestive waste (out of the mouth, rather undesirably), this feature is important for a fundamental reason of evolutionary biology. How the anus arose – and sometimes subsequently disappeared – contributes to the understanding of how animal bodyplans evolved. Moving Saccorhytus from deuterosome to ecdysozoan means striking a disappearing anus off the deuterosome case history, and adding it to the ecdysozoan one.

“This is a really unexpected result because the arthropod group have a through-gut, extending from mouth to anus. Saccorhytus’s membership of the group indicates that it has regressed in evolutionary terms, dispensing with the anus its ancestors would have inherited,” says Shuhai Xiao from Virgina Tech, USA, who co-led the study. “We still don’t know the precise position of Saccorhytus within the tree of life but it may reflect the ancestral condition from which all members of this diverse group evolved.”

The international team included researchers from the University of Bristol, Chang’an University (Xi’an, China), Nanjing Institute of Geology and Palaeontology (China), Chinese Academy of Sciences (Nanjing, China), Chinese Academy of Geological Sciences (Beijing, China), Shandong University (Qingdao, China), Swiss Light Source, Virginia Tech (USA) and First Institute of Oceanography, Ministry of Natural Resource (Qingdao, China).

Paper:

‘Saccorhytus is an early ecdysozoan and not the earliest deuterostome’ by Philip Donoghue et al in Nature.

CAPTION

Saccorhytus dorsal

CREDIT

Philip Donoghue et al

CAPTION

Saccorhytus side-on

CREDIT

Philip Donoghue et al

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JOURNAL

Nature

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Saccorhytus is an early ecdysozoan and not the earliest deuterostome’

ARTICLE PUBLICATION DATE

17-Aug-2022

Fast-growing poplars can release land for food production

Peer-Reviewed Publication

STOCKHOLM UNIVERSITY

IMAGE: HARVESTING MATURE POPLAR 26 YEARS AFTER PLANTING IN SOUTHERN SWEDEN NEAR LAKE VOMBSJÖN. PHOTO: ALMIR KARACIC view more

CREDIT: PHOTO: ALMIR KARACIC

Researchers at Stockholm University and the Swedish University of Agricultural Sciences have developed a novel value chain for production of textile and bio-fuel from fast-growing poplars. By applying sustainable catalysis on these poplars grown on marginal land in Nordic climates, the demand for cotton can be reduced. Consequently, considerable areas of productive agricultural land can be converted from cotton to food production.

Even though cotton is a biomaterial, the cultivation of cotton is not sustainable. The Aral Sea that disappeared within a few decades is a tragic yet illustrative case of the immense water demand for cultivating cotton. In contrast, in rain fed Nordic landscapes textile fibre is produced without irrigation.

Novel poplar trees

SLU, the Swedish University of Agricultural Sciences, developed novel poplar clones that have superior growth on marginal land on northern latitudes. These poplars reach full growth within 20 years, as compared to 50-100 years for current forestry trees.

Anneli Adler, researcher at SLU and the first author of an article published in the scientific journal Joule says:
“I named these clones SnowTiger as they grow fast in short rotations in northern climates. They are ´The Nordic Eucalypts´.”

Joseph Samec, Professor of Organic Chemistry at Stockholm University and the main corresponding author of the article says:

“The whole tree is converted to high value products where the cellulose becomes textile fibre while the hemicellulose and lignin are transformed to an advanced biofuel. This is noteworthy as less than 50 percent of wood is refined to textile fibre with current pulping technologies, while the rest is burnt to a low value.”

And he continues:

“This is a highly interdisciplinary study involving several institutes that demonstrate the Nordic region’s ability to contribute to global food security and irrigation challenges.”

The article “Lignin-first biorefining of Nordic poplar to produce cellulose fibers could displace cotton production on agricultural lands” is published in the journal Joule 17 August 2022.

Fast-growing poplars in a 19-year-old poplar plantation outside Uppsala. 

Photo: Almir Karacic

JOURNAL

Joule

DOI

10.1016/j.joule.2022.06.021

ARTICLE TITLE

“Lignin-first biorefining of Nordic poplar to produce cellulose fibers could displace cotton production on agricultural lands”

ARTICLE PUBLICATION DATE

17-Aug-2022

Sleeping giant could end deep ocean life

Continental movement capable of throttling marine oxygen

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - RIVERSIDE

 

IMAGE: FISH ON A DEEP REEF AT PEARL AND HERMES ATOLL IN PAPAHĀNAUMOKUĀKEA MARINE NATIONAL MONUMENT NEAR HAWAII. view more 

CREDIT: (GREG MCFALL, NOAA)

A previously overlooked factor — the position of continents — helps fill Earth’s oceans with life-supporting oxygen. Continental movement could ultimately have the opposite effect, killing most deep ocean creatures. 

“Continental drift seems so slow, like nothing drastic could come from it, but when the ocean is primed, even a seemingly tiny event could trigger the widespread death of marine life,” said Andy Ridgwell, UC Riverside geologist and co-author of a new study on forces affecting oceanic oxygen.

The water at the ocean’s surface becomes colder and denser as it approaches the north or south pole, then sinks. As the water sinks, it transports oxygen pulled from Earth’s atmosphere down to the ocean floor. 

Eventually, a return flow brings nutrients released from sunken organic matter back to the ocean’s surface, where it fuels the growth of plankton. Both the uninterrupted supply of oxygen to lower depths and organic matter produced at the surface support an incredible diversity of fish and other animals in today’s ocean.

New findings led by researchers based at UC Riverside have found this circulation of oxygen and nutrients can end quite suddenly. Using complex computer models, the researchers investigated whether the locations of continental plates affect how the ocean moves oxygen around. To their surprise, it does. 

This finding, published today, is detailed in the journal Nature.

“Many millions of years ago, not so long after animal life in the ocean got started, the entire global ocean circulation seemed to periodically shut down,” said Ridgwell. “We were not expecting to find that the movement of continents could cause surface waters and oxygen to stop sinking, and possibly dramatically affecting the way life evolved on Earth.”

Until now, models used to study the evolution of marine oxygen over the last 540 million years were relatively simple and did not account for ocean circulation. In these models, ocean anoxia — times when oceanic oxygen disappeared — implied a drop in atmospheric oxygen concentrations. 

“Scientists previously assumed that changing oxygen levels in the ocean mostly reflected similar fluctuations in the atmosphere,” said Alexandre Pohl, first author of the study and former UCR paleoclimate modeler, now at Université Bourgogne Franche-Comté in France.

This study used, for the first time, a model in which the ocean was represented in three dimensions, and in which ocean currents were accounted for.  Results show that collapse in global water circulation lead to a stark separation between oxygen levels in the upper and lower depths. 

That separation meant the entire seafloor, except for shallow places close to the coast, entirely lost oxygen for many tens of millions of years, until about 440 million years ago at the start of the Silurian period.

“Circulation collapse would have been a death sentence for anything that could not swim closer to the surface and the life-giving oxygen still present in the atmosphere,” Ridgwell said. Creatures of the deep include bizarre-looking fish, giant worms and crustaceans, squid, sponges and more.

The paper does not address if or when Earth might expect a similar event in the future, and it is difficult to identify when a collapse might occur, or what triggers it. However, existing climate models confirm that increasing global warming will weaken ocean circulation, and some models predict an eventual collapse of the branch of circulation that starts in the North Atlantic.  

“We’d need a higher resolution climate model to predict a mass extinction event,” Ridgwell said. “That said, we do already have concerns about water circulation in the North Atlantic today, and there is evidence that the flow of water to depth is declining.”

In theory, Ridgwell said an unusually warm summer or the erosion of a cliff could trigger a cascade of processes that upends life as it appears today. 

“You’d think the surface of the ocean, the bit you might surf or sail on, is where all the action is. But underneath, the ocean is tirelessly working away, providing vital oxygen to animals in the dark depths,” Ridgwell said. 

“The ocean allows life to flourish, but it can take that life away again. Nothing rules that out as continental plates continue to move.”
  

CAPTION

Red medusa found just off the bottom of the deep sea in Alaska.

CREDIT

Hidden Ocean 2005/NOAA

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JOURNAL

Nature

DOI

10.1038/s41586-022-05018-z 

METHOD OF RESEARCH

Computational simulation/modeling

ARTICLE TITLE

Continental configuration controls ocean oxygenation during the Phanerozoic

ARTICLE PUBLICATION DATE

17-Aug-2022

Plate tectonics drives ocean oxygenation

Peer-Reviewed Publication

CNRS

 

IMAGE: DARK, ORGANIC-RICH SEDIMENTS INDICATING CONDITIONS OF LOW OCEAN OXYGENATION, SANDWICHED BETWEEN LIMESTONE BEDS. view more 

CREDIT: © CHRISTOPHE THOMAZO

Until now, it has been assumed that the oxygenation of the oceans over geological timescales has mainly been driven by atmospheric oxygen levels. However, a new study published in Nature on June 27 2022  suggests otherwise. Work by scientists at the Biogeosciences Laboratory (CNRS/UBFC), together with their colleagues at the University of California's Department of Earth and Planetary Sciences, shows that the movement of tectonic plates has probably contributed to ocean oxygenation. To demonstrate this, the scientists used a three-dimensional climate model to recreate conditions on Earth from 540 million years ago to the present day, in particular taking into account ocean circulation currents. In their model, the scientists modified the position of the continents while keeping the atmospheric oxygen concentration constant. The result was that the oxygen concentration in the oceans increased, despite a constant level of oxygen in the atmosphere. The new paper thus shows for the first time that atmospheric and oceanic oxygen levels are largely independent of each other. Since oxygen is vital to marine life, these findings reveal the hitherto underestimated role played by plate tectonics in the evolution of biodiversity in the oceans over geological time scales.

CAPTION

Simulated seafloor oxygen concentration in a series of experiments in which only the configuration of the continents is modified from one period to another.

CREDIT

© Alexandre Pohl

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JOURNAL

Nature

DOI

10.1038/s41586-022-05018-z 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Continental configuration controls ocean oxygenation during the Phanerozoic

ARTICLE PUBLICATION DATE

17-Aug-2022

Floating ‘artificial leaves’ ride the wave of clean fuel production

Peer-Reviewed Publication

UNIVERSITY OF CAMBRIDGE

 

IMAGE: A FLOATING ARTIFICIAL LEAF - WHICH GENERATES CLEAN FUEL FROM SUNLIGHT AND WATER - ON THE RIVER CAM NEAR KING'S COLLEGE CHAPEL IN CAMBRIDGE, UK. view more 

CREDIT: VIRGIL ANDREI

Researchers have developed floating ‘artificial leaves’ that generate clean fuels from sunlight and water, and could eventually operate on a large scale at sea.

The researchers, from the University of Cambridge, designed ultra-thin, flexible devices, which take their inspiration from photosynthesis – the process by which plants convert sunlight into food. Since the low-cost, autonomous devices are light enough to float, they could be used to generate a sustainable alternative to petrol without taking up space on land.

Outdoor tests of the lightweight leaves on the River Cam – near iconic Cambridge sites including the Bridge of Sighs, the Wren Library and King’s College Chapel – showed that they can convert sunlight into fuels as efficiently as plant leaves.

This is the first time that clean fuel has been generated on water, and if scaled up, the artificial leaves could be used on polluted waterways, in ports or even at sea, and could help reduce the global shipping industry’s reliance on fossil fuels. The results are reported in the journal Nature.

While renewable energy technologies, such as wind and solar, have become significantly cheaper and more available in recent years, for industries such as shipping, decarbonisation is a much taller order. Around 80% of global trade is transported by cargo vessels powered by fossil fuels, yet the sector has received remarkably little attention in discussions around the climate crisis.

For several years, Professor Erwin Reisner’s research group in Cambridge has been working to address this problem by developing sustainable solutions to petrol which are based on the principles of photosynthesis. In 2019, they developed an artificial leaf, which makes syngas – a key intermediate in the production of many chemicals and pharmaceuticals – from sunlight, carbon dioxide and water.

The earlier prototype generated fuel by combining two light absorbers with suitable catalysts. However, it incorporated thick glass substrates and moisture protective coatings, which made the device bulky.

“Artificial leaves could substantially lower the cost of sustainable fuel production, but since they’re both heavy and fragile, they’re difficult to produce at scale and transport,” said Dr Virgil Andrei from Cambridge’s Yusuf Hamied Department of Chemistry, the paper’s co-lead author.

“We wanted to see how far we can trim down the materials these devices use, while not affecting their performance,” said Reisner, who led the research. “If we can trim the materials down far enough that they’re light enough to float, then it opens up whole new ways that these artificial leaves could be used.”

For the new version of the artificial leaf, the researchers took their inspiration from the electronics industry, where miniaturisation techniques have led to the creation of smartphones and flexible displays, revolutionising the field.

The challenge for the Cambridge researchers was how to deposit light absorbers onto lightweight substrates and protect them against water infiltration. To overcome these challenges, the team thin-film metal oxides and materials known as perovskites, which can be coated onto flexible plastic and metal foils. The devices were covered with micrometre thin, water-repellent carbon-based layers that prevented moisture degradation. They ended up with a device that not only works, but also looks like a real leaf.

“This study demonstrates that artificial leaves are compatible with modern fabrication techniques, representing an early step towards the automation and up-scaling of solar fuel production,” said Andrei. “These leaves combine the advantages of most solar fuel technologies, as they achieve the low weight of powder suspensions and the high performance of wired systems.”

Tests of the new artificial leaves showed that they can split water into hydrogen and oxygen, or reduce CO2 to syngas. While additional improvements will need to be made before they are ready for commercial applications, the researchers say this development opens whole new avenues in their work.

“Solar farms have become popular for electricity production; we envision similar farms for fuel synthesis,” said Andrei. “These could supply coastal settlements, remote islands, cover industrial ponds, or avoid water evaporation from irrigation canals.”

“Many renewable energy technologies, including solar fuel technologies, can take up large amounts of space on land, so moving production to open water would mean that clean energy and land use aren’t competing with one another,” said Reisner. “In theory, you could roll up these devices and put them almost anywhere, in almost any country, which would also help with energy security.”

The research was supported in part by the European Research Council, the Cambridge Trust, the Winton Programme for the Physics of Sustainability, the Royal Academy of Engineering, and the Engineering and Physical Sciences Research Council (EPSRC), part of UK Research and Innovation (UKRI). Virgil Andrei and Erwin Reisner are Fellows of St John’s College, Cambridge.

 

CAPTION

A floating artificial leaf - which generates clean fuel from sunlight and water - on the River Cam near the Bridge of Sighs in Cambridge, UK.

CREDIT

Virgil Andrei

 

CAPTION

Researchers from the University of Cambridge have designed ultra-thin, flexible devices, which take their inspiration from photosynthesis – the process by which plants convert sunlight into food. Since the low-cost, autonomous devices are light enough to float, they could be used to generate a sustainable alternative to petrol without taking up space on land.

CREDIT

Virgil Andrei

VIDEO

Researchers from the University of Cambridge designed ultra-thin, flexible devices, which take their inspiration from photosynthesis – the process by which plants convert sunlight into food. Since the low-cost, autonomous devices are light enough to float, they could be used to generate a sustainable alternative to petrol without taking up space on land.

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JOURNAL

Nature

DOI

10.1038/s41586-022-04978-6 

METHOD OF RESEARCH

Experimental study

ARTICLE TITLE

Floating perovskite-BiVO4 devices for scalable solar fuel production

ARTICLE PUBLICATION DATE

17-Aug-2022

Capturing high pressures in diamond capsules

Peer-Reviewed Publication

CENTER FOR HIGH PRESSURE SCIENCE & TECHNOLOGY ADVANCED RESEARCH

 

IMAGE: A PERSPECTIVE CARTOON DRAWING OF NANOSTRUCTURED DIAMOND CAPSULES (NDCS) WITH HIGH-PRESSURE ARGON NANODOMAINS EMBEDDED IN THE MATRIX. MODERN DIAGNOSTIC PROBES SUCH AS HARD/SOFT X-RAY, ULTRAVIOLET-VISIBLE-INFRARED LIGHT, ELECTRON, AND NEUTRON BEAMS ARE ALL APPLICABLE TO THE NDCS SAMPLES FOR INVESTIGATIONS. view more 

CREDIT: CHARLES ZENG

Preservation of the high-pressure states of materials at ambient conditions is a long-sought-after goal for fundamental research and practical applications. A team of scientists led by Drs. Zhidan (Denise) Zeng, Qiaoshi Zeng, and Ho-Kwang Mao from the Center for High Pressure Science and Technology Advanced Research (HPSTAR) and Prof. Wendy Mao from Stanford University report an innovative breakthrough where they were able to maintain the extraordinary properties of high-pressure materials in free-standing, nanostructured diamond capsules without the support of traditional bulky pressure vessels. Their work was recently published in Nature.

Modern technology is built upon access to materials with suitable physical and chemical properties that can be used to perform specific functions in various devices. Technological advances, therefore, are often dictated by the development of superior materials with desirable properties. High pressure can drastically alter or tune properties of all materials, thus providing a fertile ground for discovering novel materials with extremely favorable properties. The caveat is, however, that the favorable properties often only exist under pressure when the sample remains in the bulky high-pressure vessel, limiting scientific investigation and potential applications. For the past century, scientists have tried to overcome this difficulty. They succeeded only in "quenchable" phases, where novel materials synthesized at high pressure retain their favorable properties after releasing pressure. A well-known example is the high-pressure conversion of ordinary carbon into diamond which is able to keep its brilliance and other exceptional properties after retrieving at ordinary pressures. Unfortunately, such successful examples of quenchable phases are extremely rare, largely rendering high-pressure materials studies of only academic interest with little practical value in the ambient environment.

The HPSTAR and Stanford research group developed a novel approach that has demonstrated the ability to quench even tenuous gases and preserve their high-pressure properties. They compressed glassy carbon, an amorphous form of porous carbon, together with argon gas to 50 gigapascals — about 500,000 times atmospheric pressure, and heated the sample to 3,320 degrees Fahrenheit. The glassy carbon that is initially impermeable to gases at ordinary conditions absorbs argon like a sponge at high pressures. The application of high pressure and temperature conditions converts the carbon into diamond and traps the now solid, high-pressure argon in its pores. The resulting sample that is retrieved at ambient conditions behaves like a nanocrystalline diamond composite with numerous isolated pores that represent like tiny diamond capsules filled with argon. The residual pressure preserved in the argon by the diamond capsule is as high as 22 gigapascals — about 220 times the pressure at the bottom of the Mariana Trench. Better yet, the pressurized argon sample is sealed in by only nanometer-thick diamond skins allowing its extraordinary properties to be accessible by modern analytical probes that require near vacuum environments like electron microscopy. 

"We directly observe many nanometer-sized high-pressure argon grains encapsulated in the nano-diamond matrix by high-resolution transmission electron microscopy; thus, we named them nanostructured diamond capsules (NDCs)," explained Dr. Denise Zhidan Zeng, the lead author of this work. "One of the keys to realizing the concept of NDCs is choosing the right carbon precursor which is sp2 bonded and has pre-existing enclosed sample chambers. This is obviously by no means limited to glassy carbon. Therefore, a variety of crystalline, amorphous, and low-dimensional carbon allotropes could potentially be used as the precursor carbon as well, offering a wide range of capsule materials for optimization of the NDC process," explained Dr. Denise Zhidan Zeng.

"Using multiple complementary diagnostic probes to obtain consistent results features the modern matter research. However, in-situ high-pressure studies have always required high-penetrating probes such as hard x-ray due to the thick high-pressure vessel walls involved. Therefore, many powerful and versatile probes, such as electron microscopy and vacuum ultraviolet to soft x-ray spectroscopy, that require a near vacuum environment, unfortunately, remain incompatible with high-pressure science and technology. This has severely hindered our efforts to understand many high-pressure materials," said Dr. Qiaoshi Zeng.“By synthesizing NDCs, we offer a general method to remove bulky pressure vessels while maintaining the high-pressure conditions and therefore the high-pressure behavior in our samples. We can now employ almost all the modern diagnostic probes to obtain detailed information of the atomic/electronic structures, compositions, and bonding nature of materials at high pressures inside NDCs, including various techniques based on transmission electron microscopy. We are excited about the possibility that an approach based on NDCs will bring high-pressure explorations on par with conventional condensed-matter investigations and applications."

"Beyond the gases that we explored in our study, we also expect the concept of NDCs to be generally applicable to various solid samples," said Prof. Wendy Mao.“Moreover, NDC samples are in principle cumulative with the potential for unlimited, multiple syntheses, thus removing the limitation where high-pressure phenomena only exist in a tiny sample inside a large pressure chamber. Therefore, our work demonstrates the first, critical step toward the grand challenge of high-pressure materials applications for previously unquenchable phases."

This work involves many other co-authors from HPSTAR in China and Argonne national laboratory in USA. The financial support is from the National Key Research and Development Program of China (2019YFA0708502, 2018YFA0703400, and 2021YFA0718900) and National Natural Science Foundation of China (51871054, and U1930401).

More information: "Preservation of high-pressure volatiles in nanostructured diamond capsules", Zeng et al., 608, 513–517 Nature  (2022), https://www.nature.com/articles/s41586-022-04955-z.

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JOURNAL

Nature

DOI

10.1038/s41586-022-04955-z 

METHOD OF RESEARCH

Experimental study

ARTICLE TITLE

Preservation of high-pressure volatiles in nanostructured diamond capsules

ARTICLE PUBLICATION DATE

17-Aug-2022