Previous infection with other types of coronaviruses may lessen severity of COVID-19

 

Person blowing nose

Being previously infected with a coronaviruses that cause the "common cold" may decrease the severity of severe acute respiratory syndrome coronavirus (SARS-CoV-2) infections, according to results of a new study. Led by researchers at Boston Medical Center and Boston University School of Medicine, the study also demonstrates that the immunity built up from previous non-SARS-CoV-2 coronavirus infections does not prevent individuals from getting COVID-19. Published in the Journal of Clinical Investigation, the findings provide important insight into the immune response against SARS-CoV-2, which could have significant implications on COVID-19 vaccine development.

The COVID-19 pandemic has led to more than 200,000 deaths in the US, and more than one million globally. There is a growing body of research looking into specific ways that the SARS-CoV-2 virus impacts different populations, including why some people are infected and are asymptomatic, as well as what increases ones mortality as a result of infection. There are a number of vaccines under development in order to determine what type of vaccine (mRNA, viral vector) will be most effective at preventing SARS-CoV-2 infections.

While SARS-CoV-2 is a relatively new pathogen, there are many other types of coronaviruses that are endemic in humans and can cause the "common cold" and pneumonia. These coronaviruses share some genetic sequences with SARS-CoV-2, and the immune responses from these coronaviruses can cross-react against SARS-CoV-2.

In this study, the researchers looked at electronic medical record data from individuals who had a respiratory panel test (CRP-PCR) result between May 18, 2015 and March 11, 2020. The CRP-PCR detects diverse respiratory pathogens including the endemic "common cold" coronaviruses. They also examined data from individuals who were tested for SARS-CoV-2 between March 12, 2020 and June 12, 2020. After adjusting for age, gender, body mass index, and diabetes mellitus diagnosis, COVID-19 hospitalized patients who had a previous positive CRP-PCR test result for a coronoavirus had significantly lower odds of being admitted to the intensive care unit (ICU), and lower trending odds of requiring mechanical ventilation during COVID. The probability of survival was also significantly higher in COVID-19 hospitalized patients with a previous positive test result for a "common cold" coronoavirus. However, a previous positive test result for a coronavirus did not prevent someone from getting infected with SARS-CoV-2.

"Our results show that people with evidence of a previous infection from a "common cold" coronavirus have less severe COVID-19 symptoms," said Manish Sagar, MD, an infectious diseases physician and researcher at Boston Medical Center, associate professor of medicine and microbiology at Boston University School of Medicine and the study's co-corresponding author. Another interesting finding, the authors note, is that immunity may prevent disease (COVID-19) in ways that are different from preventing infection by SARS-CoV-2. This is demonstrated by the fact that the patient groups had similar likelihoods of infection but differing likelihoods of ending up in the ICU or dying.

"People are routinely infected with coronaviruses that are different from SARS-CoV-2, and these study results could help identify patients at lower and greater risk of developing complications after being infected with SARS-CoV-2," said Joseph Mizgerd, ScD, professor of medicine, microbiology, and biochemistry at Boston University School of Medicine who is the study's co-corresponding author. "We hope that this study can be the springboard for identifying the types of immune responses for not necessarily preventing SARS-CoV-2 infection but rather limiting the damage from COVID-19."

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Nitrous oxide emissions pose an increasing climate threat, study finds

 

Tractor spraying field

Rising nitrous oxide (N2O) emissions are jeopardizing the climate goals of the Paris Agreement, according to a major new study by an international team of scientists.

The growing use of nitrogen fertilizers in the production of food worldwide is increasing atmospheric concentrations of N2O -- a greenhouse gas 300 times more potent than carbon dioxide (CO2) that remains in the atmosphere for more than 100 years.

Published today in the journal Nature, the study was led Auburn University, in the US, and involved scientists from 48 research institutions in 14 countries -- including the University of East Anglia (UEA) in the UK -- under the umbrella of the Global Carbon Project and the International Nitrogen Initiative.

The aim was to produce the most comprehensive assessment to date of all global sources and sinks of N2O. Their findings show N2O emissions are increasing faster than any emission scenario developed by the Intergovernmental Panel on Climate Change (IPCC), consistent with greenhouse gas scenarios that lead to global mean temperature increases well above 3°C from pre-industrial levels. The Paris Agreement aims to limit warming to less than 2°C but ideally no more than 1.5°C.

The study points to an alarming trend affecting climate change: N2O has risen 20 per cent from pre-industrial levels -- from 270 parts per billion (ppb) in 1750 to 331ppb in 2018 -- with the fastest growth observed in the last 50 years due to emissions from human activities.

Prof Hanqin Tian, director of the International Center for Climate and Global Change Research at Auburn University's School of Forestry and Wildlife Sciences, co-led the study.

"The dominant driver of the increase in atmospheric nitrous oxide comes from agriculture, and the growing demand for food and feed for animals will further increase global nitrous oxide emissions," said Prof Tian. "There is a conflict between the way we are feeding people and stabilizing the climate."

Like CO2, N2O is a long-lived greenhouse gas and is also currently the most significant human-induced agent depleting the stratospheric ozone layer, which protects Earth from most of the Sun's harmful ultraviolet radiation

Lead UK author Dr Parvadha Suntharalingam, of UEA's School of Environmental Sciences, said: "This study presents the most comprehensive and detailed picture to date, of N2O emissions and their impact on climate.

"This new analysis identifies the factors driving the steadily increasing atmospheric levels of N2O, and highlights the urgent need to develop effective mitigation strategies if we are to limit global warming and meet climate goals."

The study presents a comprehensive global N2O inventory that incorporates both natural and human-related sources, and accounts for the interaction between nitrogen additions to the earth system and the biochemical processes that control N2O emissions. It covers 21 natural and human-related sectors between 1980 and 2016.

Human-induced emissions, which are dominated by nitrogen additions to croplands, increased by 30 per cent over the past four decades to 7.3 teragrams of nitrogen per year.

The analysis also reveals an emerging N2O-climate 'feedback' resulting from interactions between nitrogen additions to crops for food production and global warming, further enhancing emissions derived from agriculture.

The study found that the largest contributors to global N2O emissions come from East Asia, South Asia, Africa and South America. Emissions from synthetic fertilizers dominate releases in China, India and the US, while emissions from the application of livestock manure as fertilizer dominates releases in Africa and South America. The highest growth rates in emissions are in emerging economies, particularly Brazil, China and India, where crop production and livestock numbers have increased.

However, N2O emissions in Europe decreased in agriculture and the chemical industry. This was due to a combination of factors, including voluntary measures to remove N2O from flue gases in the Nylon industry and the introduction of an emissions trading scheme, as well as agriculture in many Western European countries moving to more efficient use of fertilizer to reduce environmental impacts such as pollution of groundwater and surface water. Policies on nitrogen fertilizer usage were also introduced.

Study co-leader Dr Josep 'Pep' Canadell, of the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia, is executive director of the Global Carbon Project. He said: "This new analysis calls for a full-scale rethink in the ways we use and abuse nitrogen fertilizers globally and urges us to adopt more sustainable practices in the way we produce food, including the reduction of food waste.

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Oldest monkey fossils outside of Africa found

 Three fossils found in a lignite mine in southeastern Yunan Province, China, are about 6.4 million years old, indicate monkeys existed in Asia at the same time as apes, and are probably the ancestors of some of the modern monkeys in the area, according to an international team of researchers.

"This is significant because they are some of the very oldest fossils of monkeys outside of Africa," said Nina G. Jablonski, Evan Pugh University Professor of Anthropology, Penn State. "It is close to or actually the ancestor of many of the living monkeys of East Asia. One of the interesting things from the perspective of paleontology is that this monkey occurs at the same place and same time as ancient apes in Asia."

The researchers, who included Jablonski and long-time collaborator Xueping Ji, department of paleoanthropology, Yunnan Institute of Cultural Relics and Archaeology, Kunming, China, studied the fossils unearthed from the Shuitangba lignite mine that has yielded many fossils. They report that "The mandible and proximal femur were found in close proximity and are probably of the same individual," in a recent issue of the Journal of Human Evolution. Also uncovered slightly lower was a left calcaneus -- heel bone -- reported by Dionisios Youlatos, Aristotle University of Thessaloniki, Greece, in another paper online in the journal, that belongs to the same species of monkey, Mesopithecus pentelicus.

"The significance of the calcaneus is that it reveals the monkey was well adapted for moving nimbly and powerfully both on the ground and in the trees," said Jablonski. "This locomotor versatility no doubt contributed to the success of the species in dispersing across woodland corridors from Europe to Asia."

The lower jawbone and upper portion of the leg bone indicate that the individual was female, according to the researchers. They suggest that these monkeys were probably "jacks of all trades" able to navigate in the trees and on land. The teeth indicate they could eat a wide variety of plants, fruits and flowers, while apes eat mostly fruit.

"The thing that is fascinating about this monkey, that we know from molecular anthropology, is that, like other colobines (Old World monkeys), it had the ability to ferment cellulose," said Jablonski. "It had a gut similar to that of a cow."

These monkeys are successful because they can eat low-quality food high in cellulose and obtain sufficient energy by fermenting the food and using the subsequent fatty acids then available from the bacteria. A similar pathway is used by ruminant animals like cows, deer and goats.

"Monkeys and apes would have been eating fundamentally different things," said Jablonski. "Apes eat fruits, flowers, things easy to digest, while monkeys eat leaves, seeds and even more mature leaves if they have to. Because of this different digestion, they don't need to drink free water, getting all their water from vegetation."

These monkeys do not have to live near bodies of water and can survive periods of dramatic climatic change.

"These monkeys are the same as those found in Greece during the same time period," said Jablonski. "Suggesting they spread out from a center somewhere in central Europe and they did it fairly quickly. That is impressive when you think of how long it takes for an animal to disperse tens of thousands of kilometers through forest and woodlands."

While there is evidence that the species began in Eastern Europe and moved out from there, the researchers say the exact patterns are unknown, but they do know the dispersal was rapid, in evolutionary terms. During the end of the Miocene when these monkeys were moving out of Eastern Europe, apes were becoming extinct or nearly so, everywhere except in Africa and parts of Southeast Asia.

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Signals from distant stars connect optical atomic clocks across Earth for the first time

 Using radio telescopes observing distant stars, scientists have connected optical atomic clocks on different continents. The results were published in the scientific journal Nature Physics by an international collaboration between 33 astronomers and clock experts at the National Institute of Information and Communications Technology (NICT, Japan), the Istituto Nazionale di Ricerca Metrologica (INRIM, Italy), the Istituto Nazionale di Astrofisica (INAF, Italy), and the Bureau International des Poids et Mesures (BIPM, France).

The BIPM in Sèvres near Paris routinely calculates the international time recommended for civil use (UTC, Coordinated Universal Time) from the comparison of atomic clocks via satellite communications. However, the satellite connections that are essential to maintaining a synchronized global time have not kept up with the development of new atomic clocks: optical clocks that use lasers interacting with ultracold atoms to give a very refined ticking. "To take the full benefit of optical clocks in UTC, it is important to improve worldwide clock comparison methods." said Gérard Petit, physicist at the Time Department at BIPM.

In this new research, highly-energetic extragalactic radio sources replace satellites as the source of reference signals. The group of SEKIDO Mamoru at NICT designed two special radio telescopes, one deployed in Japan and the other in Italy, to realize the connection using the technique of Very Long Baseline Interferometry (VLBI). These telescopes are capable of observations over a large bandwidth, while antenna dishes of just 2.4 meter diameter keep them transportable. "We want to show that broadband VLBI has potential to be a powerful tool not only for geodesy and astronomy, but also for metrology." commented SEKIDO. To reach the required sensitivity, the small antennas worked in tandem with a larger 34 m radio telescope in Kashima, Japan during the measurements taken from October 14 2018 to February 14 2019. For the Kashima radio telescope, these were among the last observations before the telescope was irreparably damaged by typhoon Faxai in September 2019.

The goal of the collaboration was to connect two optical clocks in Italy and Japan, separated by a baseline distance of 8700 km. These clocks load hundreds of ultra-cold atoms in an optical lattice, an atomic trap engineered with laser light. The clocks use different atomic species: ytterbium for the clock at INRIM and strontium at NICT. Both are candidates for a future redefinition of the second in the International System of Units (SI). "Today, the new generation of optical clocks is pushing to review the definition of the second. The road to a redefinition must face the challenge of comparing clocks globally, at the intercontinental scale, with better performances than today," said Davide Calonico, head of the "Quantum Metrology and Nanotechnology" division and coordinator of the research at INRIM.

The connection is possible by observing quasars billions of light-years away: radio sources powered by black holes weighing millions of solar masses, but so distant that they can be considered fixed points in the sky. The telescopes aim at a different star every few minutes to compensate for the effects of the atmosphere. "We observed the signal not from satellites, but from cosmic radio sources," commented IDO Tetsuya, director of the "Space-Time Standards Laboratory" and coordinator of the research at NICT. "VLBI may allow us in Asia to access the UTC relying on what we can prepare by ourselves." IDO added.

Antennas like the transportable ones used in these measurements can be installed directly at the laboratories developing optical clocks around the world. According to SEKIDO, "a global optical clock network connected by VLBI may be realized by collaboration between the international communities of metrology and geodesy, just like the broadband VLBI network of the VLBI Global Observing System (VGOS) has already been established," while Petit commented: "waiting for long-distance optical links, this research shows that there is still to gain from radio links, where VLBI with transportable antennas can complement the Global Navigation Satellite Systems and telecommunication satellites."

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Bone Loss: Perforated bone tissue from too little sugar

 Could something as simple as a certain type of sugar water be medicine for perforated bones, and even bone marrow cancer itself?

Inside our bodies are some jellyfish-like cells that actually eat away at our bones. Every year, they eat about ten per cent of the bone mass in our body. Fortunately, other cells usually follow and build up new bone.

We undergo a kind of continuous remodelling and repair that enables most of us to traipse around with steel in our legs and arms.

In people with bone marrow cancer, the bone-eating cells run amok. They become too numerous and eat too much. The bone-building gang doesn't have time to rebuild the bone mass, despite overtime and long shifts. Bone tissue gets gobbled up.

Many people with bone marrow cancer often end up with perforated bones, a condition that is very painful to live with. They sometimes experience collapsed vertebrae or suffer broken bones just by turning in bed.

For decades, scientists around the world have been scratching their heads and wondering what the cause could be. Various theories have been launched, but researchers have not reached a consensus on the main cause.

Bone marrow cancer remains an incurable disease so far. Available treatments can prolong life, but not cure the disease.

Now Standal and her research group at the Centre of Molecular Inflammation Research (CEMIR) at the Norwegian University of Science and Technology (NTNU) have discovered a piece of the puzzle that looks very promising.

They have come to the conclusion that the cause of the bone destruction is too little sugar. We're not talking about the sugar we eat in our cakes and biscuits, but sugar that resides in a substance that is important for the immune system.

To get to the bottom of how sugar is related to bone loss, we need to get into the bone marrow. This is the soft cavity that inside all our bones.

Within the bones are plasma cells. When bacteria or viruses enter the body, the plasma cells begin their job of getting rid of the invaders. Antibodies are produced which are sent via the blood, ready to do battle.

So far so good, but in people with bone marrow cancer, far too much of one type of antibody is produced. It's going amok here, too. The antibody that the cancer makes is also completely useless. It doesn't knock out either the cold or the flu but just takes up too much space and displaces other types of antibodies.

"I thought simply. If people with bone marrow cancer have too much of the antibody and too many bone-eating cells, then they must be connected," Standal says.

The search for an answer gobbled a lot of her working hours for almost five years. The hard work was fortunately not in vain, and has led to a completely new and fundamental understanding.

This is how Standal arrived at the answer:

The vast majority of patients with bone marrow cancer develop perforated bones, but not all. Standal asked nicely, and received samples from patients with bone loss. She also took samples from patients without this kind of bone loss.

The researchers extracted antibodies from the samples and cultured bone-eating cells in the laboratory.

When Standal placed the bone-eating cells into the antibody of the patients with bone perforations, she discovered that the number of bone-eating cells increased.

When she put the bone-eating cells into the antibody of the patients without bone perforations, she discovered that the number of bone-eating cells did not increase.

"Why that was the case became the next interesting thing to figure out," Standal says.

The antibody carries a type of sugar that "decorates" it, in a way. The sugar has an effect on how the antibody works. Standal found her way to Manfred Wuhrer at the Center for Proteomics and Metabolomics of the Leiden University Medical Center in the Netherlands. He is a specialist in this type of sugar, and Standal sent the samples to him.

He found that individuals with bone loss were missing two sugar molecules at the end of a long chain inside the antibody.

"There was too little sugar," says Standal.

But this answer wasn't sufficient, either.

Although a difference was detected between the two groups, the researchers could not confirm that the missing sugar molecules were the reason patients developed more bone-eating cells. Several further experiments had to be conducted.

The research team went to the lab and put more sugar on the antibody. This did not lead to more bone-eating cells. Standal also did the opposite, removing sugar from the antibody. This did lead to more bone-eating cells.

The researchers then had sufficient test results to show that too little sugar can be decisive for the number of bone-eating cells. But this is not enough in medical research -- at least not if the goal is to use the knowledge to make medicine for humans.

The next step involved animal experiments with mice that have bone marrow cancer. The mice were divided into two groups and were given two different types of sugar water. In theory, one type of sugar water would lead to more sugar on the antibody.

"The theory actually worked. The mice that received this type of sugar water had smaller perforations in their bone tissue. They also developed less cancer," says Standal.

Now she has to carry out more animal experiments to move forward on the path towards a treatment that can give patients with bone marrow cancer a better life.

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Genomic study reveals evolutionary secrets of banyan tree

 

Ficus microcarpa

The banyan fig tree Ficus microcarpa is famous for its aerial roots, which sprout from branches and eventually reach the soil. The tree also has a unique relationship with a wasp that has coevolved with it and is the only insect that can pollinate it.

In a new study, researchers identify regions in the banyan fig's genome that promote the development of its unusual aerial roots and enhance its ability to signal its wasp pollinator.

The study, published in the journal Cell, also identifies a sex-determining region in a related fig tree, Ficus hispida. Unlike F. microcarpa, which produces aerial roots and bears male and female flowers on the same tree, F. hispida produces distinct male and female trees and no aerial roots.

Understanding the evolutionary history of Ficus species and their wasp pollinators is important because their ability to produce large fruits in a variety of habitats makes them a keystone species in most tropical forests, said Ray Ming, a plant biology professor at the University of Illinois, Urbana-Champaign who led the study with Jin Chen, of the Chinese Academy of Sciences. Figs are known to sustain at least 1,200 bird and mammal species. Fig trees were among the earliest domesticated crops and appear as sacred symbols in Hinduism, Buddhism and other spiritual traditions.

The relationship between figs and wasps also presents an intriguing scientific challenge. The body shapes and sizes of the wasps correspond exactly to those of the fig fruits, and each species of fig produces a unique perfume to attract its specific wasp pollinator.

To better understand these evolutionary developments, Ming and his colleagues analyzed the genomes of the two fig species, along with that of a wasp that pollinates the banyan tree.

"When we sequenced the trees' genomes, we found more segmental duplications in the genome of the banyan tree than in F. hispida, the fig without the aerial roots," Ming said. "Those duplicated regions account for about 27% of the genome."

The duplications increased the number of genes involved in the synthesis and transport of auxins, a class of hormones that promote plant growth. The duplicated regions also contained genes involved in plant immunity, nutrition and the production of volatile organic compounds that signal pollinators.

"The levels of auxin in the aerial roots are five times higher than in the leaves of trees with or without aerial roots," Ming said. The elevated auxin levels appear to have triggered aerial root production. The duplicated regions also include genes that code for a light receptor that accelerates auxin production.

When they studied the genome of the fig wasp and compared it with those of other related wasps, the researchers observed that the wasps were retaining and preserving genes for odorant receptors that detect the same smelly compounds the fig trees produce. These genomic signatures are a signal of coevolution between the fig trees and the wasps, the researchers report.

Ming and his colleagues also discovered a Y chromosome-specific gene that is expressed only in male plants of F. hispida and three other fig species that produce separate male and female plants, a condition known as dioecy.

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Moon's magnetic crust research sees scientists debunk long-held theory

 New international research into the Moon provides scientists with insights as to how and why its crust is magnetised, essentially 'debunking' one of the previous longstanding theories.

Australian researcher and study co-author Dr Katarina Miljkovic, from the Curtin Space Science and Technology Centre, located within the School of Earth and Planetary Sciences at Curtin University, explained how the new research, published by Science Advances, expands on decades of work by other scientists.

"There are two long term hypotheses associated with why the Moon's crust might be magnetic: One is that the magnetisation is the result of an ancient dynamo in the lunar core, and the other is that it's the result of an amplification of the interplanetary magnetic field, created by meteoroid impacts," Dr Miljkovic said.

"Our research is a deep numerical study that challenges that second theory -- the impact-related magnetisation -- and it essentially 'debunks' it. We found that meteoroid impact plasmas interact much more weakly with the Moon compared to the magnetisation levels obtained from the lunar crust.

"This finding leads us to conclude that a core dynamo is the only plausible source of the magnetisation of the Moon's crust."

To carry out her portion of the research, Dr Miljkovic provided the team with numerical estimates of the vapour formation that occurred during large meteoroid impact bombardment on the Moon approximately 4 billion years ago.

"When we look at the Moon with the naked eye, we can see these large craters caused by ancient meteoroid impacts. They are now filled with volcanic maria, or seas, causing them to look darker on the surface," Dr Miljkovic said.

"During these impact events, the meteoroids hit the Moon at a very high speed, causing displacement, melting, and vaporisation of the lunar crust.

"My work calculated the mass and thermal energy of the vapour emitted during these impacts. That was then used as input for further calculations and investigation of the behaviour of the ambient magnetic field at the Moon, following these large impact events.

"Basically, we made a much more inclusive, high fidelity and high-resolution investigation that led to debunking of the older hypothesis."

The study's lead researcher Dr Rona Oran, a research scientist in the Department of Earth, Atmospheric and Planetary Sciences (EAPS) at the Massachusetts Institute of Technology (MIT), said the impact simulations, combined with plasma simulations, harness the latest developments in scientific codes and computing power and allowed the team to perform the first simulations that could realistically capture and test this long-proposed mechanism.

Using such tools was key to allowing the team to look at many different scenarios, and in this way to rule out this mechanism under any feasible conditions that could have existed during the impact. This refutation could have important implications to determine what did magnetise the Moon, and even other objects in the solar system with unexplainable magnetised crusts.

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New solar panel design could lead to wider use of renewable energy

 Designing solar panels in checkerboard lines increases their ability to absorb light by 125 per cent, a new study says.

Researchers say the breakthrough could lead to the production of thinner, lighter and more flexible solar panels that could be used to power more homes and be used in a wider range of products.

The study -- led by researchers from the University of York and conducted in partnership with NOVA University of Lisbon (CENIMAT-i3N) -- investigated how different surface designs impacted on the absorption of sunlight in solar cells, which put together form solar panels.

Scientists found that the checkerboard design improved diffraction, which enhanced the probability of light being absorbed which is then used to create electricity.

The renewable energy sector is constantly looking for new ways to boost the light absorption of solar cells in lightweight materials that can be used in products from roof tiles to boat sails and camping equipment.

Solar grade silicon -- used to create solar cells -- is very energy intensive to produce, so creating slimmer cells and changing the surface design would make them cheaper and more environmentally friendly.

Dr Christian Schuster from the Department of Physics said: "We found a simple trick for boosting the absorption of slim solar cells. Our investigations show that our idea actually rivals the absorption enhancement of more sophisticated designs -- while also absorbing more light deep in the plane and less light near the surface structure itself.

"Our design rule meets all relevant aspects of light-trapping for solar cells, clearing the way for simple, practical, and yet outstanding diffractive structures, with a potential impact beyond photonic applications.

"This design offers potential to further integrate solar cells into thinner, flexible materials and therefore create more opportunity to use solar power in more products."

The study suggests the design principle could impact not only in the solar cell or LED sector but also in applications such as acoustic noise shields, wind break panels, anti-skid surfaces, biosensing applications and atomic cooling.

Dr Schuster added: "In principle, we would deploy ten times more solar power with the same amount of absorber material: ten times thinner solar cells could enable a rapid expansion of photovoltaics, increase solar electricity production, and greatly reduce our carbon footprint.

"In fact, as refining the silicon raw material is such an energy-intensive process, ten times thinner silicon cells would not only reduce the need for refineries but also cost less, hence empowering our transition to a greener economy."

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Silk fibers improve bioink for 3D-printed artificial tissues and organs

 How do you test, in early-stage research, whether a potential pharmaceutical effectively targets a human tumor, organ, or some other part of the body? How do you grow a new hand or some other body part? Researchers are in the early stages of using 3D cell printing technology to make developments like these happen. A standard way -- currently unavailable -- to fix the cells in place after printing would help researchers avoid having to 'reinvent the wheel' in every new investigation.

In a study recently published in Materials Today Bio, researchers from Osaka University have used silk nanofibers obtained by mechanical disintegration to enhance the printing process without damaging the cells or cell assemblies. An attractive point of silk for this application is that silk is believed to be a safe material for humans. This development will help bring 3D cell printing research out of the laboratory and into real-world biomedical use.

To obtain the fibers, the researchers started with virgin silk, then removed the protein sericin from it because this protein causes inflammation in patients. Next, the researchers ground the remaining biocompatible material into nanofibers. The fibers can be sterilized -- without damaging them -- for medical use, with common laboratory equipment.

"Our silk fibers are excellent additives to bioink cell printing media," says lead author Shinji Sakai. "They are compatible with many media, such as those containing gelatin, chitosan, or hyaluronic acid, giving them a broad range of potential applications."

The main purpose of the fibers was to ensure that the cells in the bioink retained their 3D positioning after printing without damaging the cells. The fibers fulfill this purpose by enhancing the integrity of the bioink and minimizing the damaging high mechanical stresses often placed on cells during printing.

"Various mechanical experiments say the same thing: the nanofibers enhanced the properties of the printing media," explains Professor Sakai. "For example, Young's modulus -- a measure of stiffness -- increased several-fold and remained enhanced for over a month."

The fibers help printed configurations retain their structural integrity after printing. For example, a nose-shaped configuration retained its shape only when printed with bioink containing the silk fibers. Over 85% of the cells in the bioink remained alive after a week in the printed bioink with or without the added fibers, indicating that adding the fibers did not damage the cells.

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New research explores how super flares affect planets' habitability

 

Exoplanet illustration

Ultraviolet light from giant stellar flares can destroy a planet's habitability. New research from the University of North Carolina at Chapel Hill will help astrobiologists understand how much radiation planets experience during super flares and whether life could exist on worlds beyond our solar system.

Super flares are bursts of energy that are 10 to 1,000 times larger than the biggest flares from the Earth's sun. These flares can bathe a planet in an amount of ultraviolet light huge enough to doom the chances of life surviving there.

Researchers from UNC-Chapel Hill have for the first time measured the temperature of a large sample of super flares from stars, and the flares' likely ultraviolet emissions. Their findings, published Oct. 5 ahead of print in Astrophysical Journal, will allow researchers to put limits on the habitability of planets that are targets of upcoming planet-finding missions.

"We found planets orbiting young stars may experience life-prohibiting levels of UV radiation, although some micro-organisms might survive," said lead study author Ward S. Howard, a doctoral student in the Department of Physics and Astronomy at UNC-Chapel Hill.

Howard and colleagues at UNC-Chapel Hill used the UNC-Chapel Hill Evryscope telescope array and NASA's Transiting Exoplanet Survey Satellite (TESS) to simultaneously observe the largest sample of super flares.

The team's research expands upon previous work that has largely focused on flare temperatures and radiation from only a handful of super flares from a few stars. In expanding the research, the team discovered a statistical relationship between the size of a super flare and its temperature. The temperature predicts the amount of radiation that potentially precludes on-surface life.

Super flares typically emit most of their UV radiation during a rapid peak lasting only five to 15 minutes. The simultaneous Evryscope and TESS observations were obtained at two-minute intervals, ensuring multiple measurements were taken during the peak of each super flare.

This is the first time the temperatures of such a large sample of super flares has ever been studied. The frequency of observations allowed the team to discover the amount of time super flares can cook orbiting planets with intense UV radiation.

The flares observed have already informed the TESS Extended Mission to discover thousands of exoplanets in orbit around the brightest dwarf stars in the sky. TESS is now targeting high priority flare stars from the UNC-Chapel Hill sample for more frequent observations.

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