Tech

In spring 2018, the surprising discovery of superconductivity in a new material set the scientific community abuzz. Built by layering one carbon sheet atop another and twisting the top one at a "magic" angle, the material enabled electrons to flow without resistance, a trait that could dramatically boost energy efficient power transmission and usher in a host of new technologies.

Now, new experiments conducted at Princeton give hints at how this material -- known as magic-angle twisted graphene -- gives rise to superconductivity. In this week's issue of the journal Nature, Princeton researchers provide firm evidence that the superconducting behavior arises from strong interactions between electrons, yielding insights into the rules that electrons follow when superconductivity emerges.

"This is one of the hottest topics in physics," said Ali Yazdani, the Class of 1909 Professor of Physics and senior author of the study. "This is a material that is incredibly simple, just two sheets of carbon that you stick one on top of the other, and it shows superconductivity."

Exactly how superconductivity arises is a mystery that laboratories around the world are racing to solve. The field even has a name, "twistronics."

Part of the excitement is that, compared to existing superconductors, the material is quite easy to study since it only has two layers and only one type of atom -- carbon.

"The main thing about this new material is that it is a playground for all these kinds of physics that people have been thinking about for the last 40 years," said B. Andrei Bernevig, a professor of physics specializing in theories to explain complex materials.

The superconductivity in the new material appears to work by a fundamentally different mechanism from traditional superconductors, which today are used in powerful magnets and other limited applications. This new material has similarities to copper-based, high-temperature superconductors discovered in the 1980s called cuprates. The discovery of cuprates led to the Nobel Prize in Physics in 1987.

The new material consists of two atomically thin sheets of carbon known as graphene. Also the subject of a Nobel Prize in Physics, in 2010, graphene has a flat honeycomb pattern, like a sheet of chicken wire. In March 2018, Pablo Jarillo-Herrero and his team at the Massachusetts Institute of Technology placed a second layer of graphene atop the first, then rotated the top sheet by the "magic" angle of about 1.1 degrees. This angle had been predicted earlier by physicists to cause new electron interactions, but it came as a shock when MIT scientists demonstrated superconductivity.

Seen from above, the overlapping chicken-wire patterns give a flickering effect known as "moiré," which arises when two geometrically regular patterns overlap, and which was once popular in the fabrics and fashions of 17th and 18th century royals.

These moiré patterns give rise to profoundly new properties not seen in ordinary materials. Most ordinary materials fall into a spectrum from insulating to conducting. Insulators trap electrons in energy pockets or levels that keep them stuck in place, while metals contain energy states that permit electrons to flit from atom to atom. In both cases, electrons occupy different energy levels and do not interact or engage in collective behavior.

In twisted graphene, however, the physical structure of the moiré lattice creates energy states that prevent electrons from standing apart, forcing them to interact. "It is creating a condition where the electrons can't get out of each other's way, and instead they all have to be in similar energy levels, which is prime condition to create highly entangled states," Yazdani said.

The question the researchers addressed was whether this entanglement has any connection with its superconductivity. Many simple metals also superconduct, but all the high-temperature superconductors discovered to date, including the cuprates, show highly entangled states caused by mutual repulsion between electrons. The strong interaction between electrons appears to be a key to achieve higher temperature superconductivity.

To address this question, Princeton researchers used a scanning tunneling microscope that is so sensitive that it can image individual atoms on a surface. The team scanned samples of magic-angle twisted graphene in which they controlled the number of electrons by applying a voltage to a nearby electrode. The study provided microscopic information on electron behavior in twisted bilayer graphene, whereas most other studies to date have monitored only macroscopic electrical conduction.

By dialing the number of electrons to very low or very high concentrations, the researchers observed electrons behaving almost independently, as they would in simple metals. However, at the critical concentration of electrons where superconductivity was discovered in this system, the electrons suddenly displayed signs of strong interaction and entanglement.

At the concentration where superconductivity emerged, the team found that the electron energy levels became unexpectedly broad, signals that confirm strong interaction and entanglement. Still, Bernevig emphasized that while these experiments open the door to further study, more work needs to be done to understand in detail the type of entanglement that is occurring.

"There is still so much we don't know about these systems," he said. "We are nowhere near even scraping the surface of what can be learned through experiments and theoretical modeling."

Contributors to the study included Kenji Watanabe and Takashi Taniguchi of the National Institute for Material Science in Japan; graduate student and first author Yonglong Xie, postdoctoral research fellow Berthold Jäck, postdoctoral research associate Xiaomeng Liu, and graduate student Cheng-Li Chiu in Yazdani's research group; and Biao Lian in Bernevig's research group.

A new study harnessed the unique genetic history of the people of Finland to identify variations in DNA that might predispose certain individuals to disease, whether or not they are Finnish themselves. The study was conducted by researchers at Washington University School of Medicine in St. Louis, in collaboration with the University of California, Los Angeles; the University of Michigan and other institutions, including several partners in Finland.

The research, published July 31 in the journal Nature, identified 26 potentially harmful DNA variations relevant to cardiovascular and metabolic health. For example, such variations might alter a person's lifetime risk of developing obesity, diabetes or high cholesterol levels. Though this analysis is just a starting point to delve more deeply into the health consequences of these types of DNA variants, the study is an important milestone in demonstrating the effectiveness of this population approach to genetic research. Of the 26 DNA variations identified, 19 are either unique to Finnish individuals or over 20 times more frequent in Finland compared with elsewhere in Europe.

Without this unique population -- isolated and relatively genetically similar -- the researchers estimate they would need to sequence the DNA of hundreds of thousands to millions of people to find these same associations, rather than the relatively manageable 20,000 individuals analyzed in this study.

According to the investigators, this study is among the most comprehensive examinations of the impact of coding variation -- DNA changes that impact protein structure and function -- on measures of cardiovascular and metabolic health, an endeavor greatly facilitated by Finnish population history.

"The small population of people who first settled this part of the world -- combined with relatively little immigration that would add variation to the gene pool -- has pushed important genetic variants that first existed in the founding population to expand and become much more common than they would be elsewhere," said first author Adam E. Locke, PhD, an assistant professor of medicine at Washington University School of Medicine in St. Louis. "Now we can delve into the patient data -- which is extremely well-characterized through Finland's national health-care system -- to understand how these genetic variants influence overall health and disease risk in the people who have them."

Finland is a relatively isolated country, and with two major population bottlenecks over its history, the Finnish people have DNA more similar to one another than people in many other parts of the world. Such bottlenecks occur when a major event -- perhaps a violent conflict, disease or natural disaster -- causes a large drop in population. The population that then expands after the event is more genetically similar than before. The effect has produced a set of genetic diseases -- called the Finnish Disease Heritage -- that can occur anywhere but are much more common in Finland than in other European populations. Conditions listed on the Finnish Disease Heritage are caused by mutations in a single gene and often have severe effects on health.

Though many studies have employed the unique history of the Finnish people for genetic discovery, this is among the first to comprehensively examine the impact of rare, coding DNA variants -- the kind that impact protein structure and function -- on common conditions that typically involve more subtle changes in genetics than those driving the conditions of the Finnish Disease Heritage.

According to the researchers, some of the more intriguing DNA variants identified are associated with changes in cholesterol levels, differences in levels of amino acids in the blood -- which, depending on the specific amino acids, can suggest a number of health problems, including liver or kidney dysfunction -- and changes in height and body weight.

Locke said his work primarily is focused on data from Finland, but the researchers would like to expand this type of study to include similarly isolated populations of people from different parts of the world. For example, communities of people living on islands such as Sardinia in Italy, Crete in Greece or the Samoan Islands in the South Pacific also might provide similarly genetically unique populations to study, and perhaps highlight some different yet universal aspects of human health.

Scientists from Northwestern University and Caltech have produced electricity by simply flowing water over extremely thin layers of inexpensive metals, including iron, that have oxidized. These films represent an entirely new way of generating electricity and could be used to develop new forms of sustainable power production.

The films have a conducting metal nanolayer (10 to 20 nanometers thick) that is insulated with an oxide layer (2 nanometers thick). Current is generated when pulses of rainwater and ocean water alternate and move across the nanolayers. The difference in salinity drags the electrons along in the metal below.

"It's the oxide layer over the nanometal that really makes this device go," said Franz M. Geiger, the Dow Professor of Chemistry in Northwestern's Weinberg College of Arts and Sciences. "Instead of corrosion, the presence of the oxides on the right metals leads to a mechanism that shuttles electrons."

The films are transparent, a feature that could be taken advantage of in solar cells. The researchers intend to study the method using other ionic liquids, including blood. Developments in this area could lead to use in stents and other implantable devices.

"The ease of scaling up the metal nanolayer to large areas and the ease with which plastics can be coated gets us to three-dimensional structures where large volumes of liquids can be used," Geiger said. "Foldable designs that fit, for instance, into a backpack are a possibility as well. Given how transparent the films are, it's exciting to think about coupling the metal nanolayers to a solar cell or coating the outside of building windows with metal nanolayers to obtain energy when it rains."

The study, titled "Energy Conversion via Metal Nanolayers," was published this week in the journal Proceedings of the National Academy of Sciences (PNAS).

Geiger is the study's corresponding author; his Northwestern team conducted the experiments. Co-author Thomas Miller, professor of chemistry at Caltech, led a team that conducted atomistic simulations to study the device's behavior at the atomic level.

The new method produces voltages and currents comparable to graphene-based devices reported to have efficiencies of around 30% -- similar to other approaches under investigation (carbon nanotubes and graphene) but with a single-step fabrication from earth-abundant elements instead of multistep fabrication. This simplicity allows for scalability, rapid implementation and low cost. Northwestern has filed for a provisional patent.

Of the metals studied, the researchers found that iron, nickel and vanadium worked best. They tested a pure rust sample as a control experiment; it did not produce a current.

The mechanism behind the electricity generation is complex, involving ion adsorption and desorption, but it essentially works like this: The ions present in the rainwater/saltwater attract electrons in the metal beneath the oxide layer; as the water flows, so do those ions, and through that attractive force, they drag the electrons in the metal along with them, generating an electrical current.

"There are interesting prospects for a variety of energy and sustainability applications, but the real value is the new mechanism of oxide-metal electron transfer," Geiger said. "The underlying mechanism appears to involve various oxidation states."

The team used a process called physical vapor deposition (PVD), which turns normally solid materials into a vapor that condenses on a desired surface. PVD allowed them to deposit onto glass metal layers only 10 to 20 nanometers thick. An oxide layer then forms spontaneously in air. It grows to a thickness of 2 nanometers and then stops growing.

"Thicker films of metal don't succeed -- it's a nano-confinement effect," Geiger said. "We have discovered the sweet spot."

When tested, the devices generated several tens of millivolts and several microamps per centimeter squared.

"For perspective, plates having an area of 10 square meters each would generate a few kilowatts per hour -- enough for a standard U.S. home," Miller said. "Of course, less demanding applications, including low-power devices in remote locations, are more promising in the near term."

Understanding the internal energy flow - including the metabolism - of large ocean creatures like sharks and rays could be key to their survival in a changing climate, according to a new study.

University of Queensland PhD candidate Christopher Lawson led a team of researchers investigating the bioenergetics of sharks and rays; data which may reveal how they will fare in a drastically changing ocean.

"Shark and rays play crucial roles as top predators in many marine ecosystems, but are currently among the most threatened vertebrates," Mr Lawson said.

"Based on historical extinctions, it looks like they're highly susceptible to future environmental changes, so a changing climate could severely affect their populations.

"These animals are ectotherms - or cold-blooded - so their body temperature is reliant on the temperature of their environment.

"Warming oceans mean their metabolic rate increases with temperature, and they'll have to consume more food otherwise their growth or reproductive rate could suffer."

To make matters worse for these ocean giants, Mr Lawson and his colleagues believe the species will face compounding climate pressures.

"Climate change is also changing the available habitat for these animals, with some parts of the ocean becoming too warm or having reduced oxygen levels," he said.

"And many prey species are shifting their distribution - meaning that while large sharks and rays may need to consume more food, there might be less of it available.

"Ultimately this can limit reproduction levels and we may see a decline in many of these already-threatened species."

The study's data was compiled from various research projects from the last five years, identifying the most effective and promising bioenergetics analysis methods.

"Measuring the energy use of large sharks and rays is really quite difficult," Mr Lawson said.

"It's even more so than other extremely large animals like whales or elephants, which can be more easily accessed, so there's a lack of data in this area.

"Now we're looking at utilising technological advances in data loggers and tags - that can be physically attached to the animals - collaborating with large public aquariums, using sophisticated computer modelling and even machine-learning.

"We really need more research in this space, which may prove critical in saving our big ocean hunters."

Plastic waste that finds its way into oceans and rivers poses a global environmental threat with damaging health consequences for animals, humans, and ecosystems. Now, using tiny coil-shaped carbon-based magnets, researchers in Australia have developed a new approach to purging water sources of the microplastics that pollute them without harming nearby microorganisms. Their work appears July 31 in the journal Matter.

"Microplastics adsorb organic and metal contaminants as they travel through water and release these hazardous substances into aquatic organisms when eaten, causing them to accumulate all the way up the food chain" says senior author Shaobin Wang, a professor of chemical engineering at the University of Adelaide (Australia). "Carbon nanosprings are strong and stable enough to break these microplastics down into compounds that do not pose such a threat to the marine ecosystem."

Although often invisible to the naked eye, microplastics are ubiquitous pollutants. Some, such as the exfoliating beads found in popular cosmetics, are simply too small to be filtered out during industrial water treatment. Others are produced indirectly, when larger debris like soda bottles or tires weather amid sun and sand.

To decompose the microplastics, the researchers had to generate short-lived chemicals called reactive oxygen species, which trigger chain reactions that chop the various long molecules that make up microplastics into tiny and harmless segments that dissolve in water. However, reactive oxygen species are often produced using heavy metals such as iron or cobalt, which are dangerous pollutants in their own right and thus unsuitable in an environmental context.

To get around this challenge, the researchers found a greener solution in the form of carbon nanotubes laced with nitrogen to help boost generation of reactive oxygen species. Shaped like springs, the carbon nanotube catalysts removed a significant fraction of microplastics in just eight hours while remaining stable themselves in the harsh oxidative conditions needed for microplastics breakdown. The coiled shape increases stability and maximises reactive surface area. As a bonus, by including a small amount of manganese, buried far from the surface of the nanotubes to prevent it from leaching into water, the minute springs became magnetic.

"Having magnetic nanotubes is particularly exciting because this makes it easy to collect them from real wastewater streams for repeated use in environmental remediation," says Xiaoguang Duan, a chemical engineering research fellow at Adelaide who also co-led the project.

As no two microplastics are chemically quite the same, the researchers' next steps will center on ensuring that the nanosprings work on microplastics of different compositions, shapes and origins. They also intend to continue to rigorously confirm the non-toxicity of any chemical compounds occurring as intermediates or by-products during microplastics decomposition.

The researchers also say that those intermediates and byproducts could be harnessed as an energy source for microorganisms that the polluting plastics currently plague. "If plastic contaminants can be repurposed as food for algae growth, it will be a triumph for using biotechnology to solve environmental problems in ways that are both green and cost efficient," Wang says.

Researchers have found that anti-inflammatory biologic therapies used to treat moderate to severe psoriasis can significantly reduce coronary inflammation in patients with the chronic skin condition. Scientists said the findings are particularly notable because of the use of a novel imaging biomarker, the perivascular fat attenuation index (FAI), that was able to measure the effect of the therapy in reducing the inflammation.

The study published online in JAMA Cardiology, has implications not just for people with psoriasis, but for those with other chronic inflammatory diseases, such as lupus and rheumatoid arthritis. These conditions are known to increase the risk for heart attacks and strokes. The study was funded by the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health,

"Coronary inflammation offers important clues about the risk of developing heart artery disease," said study's senior author Nehal N. Mehta, M.D., a cardiologist and head of the Lab of Inflammation and Cardiometabolic Diseases at NHLBI. "Our findings add to the growing body of research that shows treating underlying inflammatory conditions may reduce the risk of cardiovascular diseases."

The researchers analyzed 134 patients who suffered moderate to severe psoriasis and had not received biologic treatment for at least three months before starting on the study's therapy. Fifty-two of these patients who chose not to receive the biologic therapy, were treated with topical or light therapies only and served as the control group. The participants are from an ongoing, prospective cohort study, the Psoriasis Atherosclerosis Cardiometabolic Initiative cohort at NIH.

Coronary artery inflammation particularly affects perivascular fat--the fat tissue surrounding arteries--by changing its composition, making it attenuated, or less fatty, as captured by the perivascular fat attenuation index (FAI), which researchers in the current study used to measure the effects of the biologics on coronary inflammation.

"FAI is a new method of analyzing CT scans that can predict a patient's risk of fatal heart attacks and other cardiac events years in advance, and independent of other traditional risk factors for heart disease," explained study co-author Charalambos Antoniades, M.D., professor of cardiovascular medicine at Oxford University. "In fact, our research has found that an abnormal perivascular FAI was linked to a six- to nine-fold increased risk of major adverse cardiovascular events."

The 134 patients, all of whom had low cardiovascular risk, underwent CT scans at the start of the study and again a year later to assess coronary inflammation using the perivascular FAI. Researchers found a significant reduction in coronary inflammation among those receiving biologic therapy, but there was no change in the control group. Even patients with preexisting coronary artery plaque saw a reduction in coronary inflammation following biologic therapy.

"After seeing the predicting value of the perivascular FAI for cardiac events, a key lingering question was if we could modify it using anti-inflammatory interventions. As far as we know, our study is the first to assess potential effects of biologic therapy on coronary inflammation using the measure," said Mehta.

The researchers believe that the strength of the perivascular FAI in predicting the risk of future cardiac events could guide therapeutic decisions for individual patients, promoting a more personalized medicine approach to care.

Psoriasis, a common skin disease affecting 3% to 5% of the U.S. population, is associated with heightened systemic inflammation, which elevates risk of blood vessel disease and diabetes. Inflammation occurs when the body's defensive mechanism kicks in to ward off infection or disease, but this mechanism can turn against itself when triggered, for instance, by excess low-density lipoproteins (LDLs) that seep into the lining of the arteries.

The resulting inflammatory response can increase formation of blood clots, which block arteries leading to heart attack and stroke. Inflammation puts 20% to 30% of the U.S. population at risk for these kinds of events.

Bottom Line: The incidence of colorectal cancer among younger adults increased in recent years in this analysis of data from Canadian national cancer registries that included about 688,000 new colorectal cancers diagnosed over more than 40 years. Among men younger than 50, there was an average annual percentage change of 3.47% from 2006 to 2015. Among women younger than 50, there was an average annual percentage change of 4.45% from 2010 to 2015. Because the study used registry data, authors didn't have access to any demographic information other than age so they were unable to identify what other factors may be associated with the increases. Potential reasons to explain the increases are not well understood and the authors suggest that be investigated before any change in screening guidelines is pursued.

Authors: Darren R. Brenner, Ph.D., University of Calgary, Alberta, Canada, and coauthors

(doi:10.1001/jamanetworkopen.2019.8090)

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

Insights into how minute, yet powerful, bubbles form and collapse on underwater surfaces could help make industrial structures such as ship propellers more hardwearing, research suggests.

Supercomputer calculations have revealed details of the growth of so-called nanobubbles, which are tens of thousands of times smaller than a pin head.

The findings could lend valuable insight into damage caused on industrial structures, such as pump components, when these bubbles burst to release tiny but powerful jets of liquid.

This rapid expansion and collapse of bubbles, known as cavitation, is a common problem in engineering but is not well understood.

Engineers at the University of Edinburgh devised complex simulations of air bubbles in water, using the UK's national supercomputer.

The team modelled the motion of atoms in the bubbles and observed how they grew in response to small drops in water pressure.

They were able to determine the critical pressure needed for bubble growth to become unstable, and found that this was much lower than suggested by theory.

Their findings could inform the development of nanotechnologies to harness the power of thousands of jets from collapsing nanobubbles, such as therapies to target some cancers, or for cleaning high-precision technical equipment. Researchers have proposed an updated theory on the stability of surface nanobubbles, based on their findings.

Their study, published in Langmuir, was supported by the Engineering and Physical Sciences Research Council.

Duncan Dockar, of the University of Edinburgh's School of Engineering, said: "Bubbles routinely form and burst on surfaces that move through fluids and the resulting wear can cause drag and critical damage. We hope our insights, made possible with complex computing, can help limit the impact on machine performance and enable future technologies."

DURHAM, N.H.-- As the Trump administration opens millions of acres of once protected land and coastline for oil and natural gas exploration, there is mounting concern about the potential impact on the environment as well as those who enjoy the outdoors. Researchers at the University of New Hampshire took a closer look at one of these industries, shale natural gas energy development (SGD), and how it is affecting the experiences of outdoor recreationists, like hikers and campers. They found a significant number of recreationists encountered SGD-related activities and a smaller number even changed their outdoor recreation behaviors or experiences as a result of encountering SGD.

"What most people don't realize is that a lot of the shale natural gas energy development is happening within or adjacent to public parks and protected areas," said Michael Ferguson, assistant professor of recreation management and policy. "So those who love playing in the great outdoors are often encountering anything from heavy duty truck traffic congestion to actual construction and drilling operations while recreating on public lands."

In the study, recently published in the Journal of Outdoor Recreation and Tourism, the researchers from UNH and Penn State University examined more closely the factors that may impact recreationists in Pennsylvania. They found that 12.3% of Pennsylvania outdoor recreationists were substantially impacted by SGD activities, especially in areas were SGD was most prominent (North Central and Southwest, Pennsylvania). 13.8% of respondents ended up changing their plans, avoided a certain area, or no longer traveled to the state to enjoy outdoor activities. The largest group, 23.8%, encountered some form of SGD activity including actual well sites, heavy truck traffic, pipelines, or SGD workers. Overall, the study authors say the findings suggest that a certain sub-population of recreationists sometimes altered their outdoor recreation plans because they perceived a lack of 'fit' between the SGD and the parks and protected areas of Pennsylvania.

According to the Outdoor Industry Association, in 2017, the U.S. outdoor recreation economy generated $887 billion in annual consumer spending and employed over 7 million people which is 42 times as many individuals in the U.S. employed by the oil and gas industry.

"The outdoor recreation industry has quietly positioned itself as a massive economic sector in the United States", said Ferguson. "As SGD grows in the United States, the number of affected recreationists could increase and current numbers of those impacted could rise. It is important for lawmakers, natural resource managers, and industry representatives to recognize that outdoor recreation is an increasingly critical component of the economy and should have a seat at the table when looking at responsible SGD."

Researchers say this is especially true as SGD companies attempt to gain public support in Pennsylvania and other states that have natural gas deposits. While this study was conducted in Pennsylvania, the researchers say the findings could be applied to other similar public lands experiencing SGD in states like Texas, Oklahoma, Louisiana, and Colorado.

A novel structural color soft robot with both color-changing and locomotion capabilities has been developed by a research team led by Dr. DU Xuemin from the Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences.

Inspired by the color-changing capability of the chameleon, which can actively tune a lattice of light-reflecting nanocrystals in its top layer of skin cells - the iridophores - in order to adapt to the changing environment, the structural color soft robot is able to sense the changing environment, thus exhibiting vivid color alterations and programmable locomotion. This capability will pave the way for advances in robot-environment interaction, such as sensing, response and communication.

Thanks to its periodic structure and asymmetric friction design, which ensure fast color alteration and programmable shape transformation (in less than 1s), the worm-like structural robot can move forward straight and rhythmically, exhibiting dynamic color change when the environment changes.

These extraordinary properties were used to develop a rotating pinwheel and a closing/blooming flower featuring brilliant color changes. These smart actuations could have important implications in sensing, communication and disguise for soft robotics.

New research published in Molecular Cell on 31 July 2019 conducted by researchers from the University of Konstanz's Collaborative Research Centre 969 "Chemical and Biological Principles of Cellular Proteostasis" shows that the nascent polypeptide-associated complex (NAC) acts as a major protein identifying and, possibly, sorting device inside the cell. Working closely with Professor Nenad Ban, an expert for resolving ribosomal structures from ETH Zurich, the team led by Professor Elke Deuerling and Dr Martin Gamerdinger from the University of Konstanz's Department of Biology - including co-workers Annalena Wallisch, Dr Stefan Kreft, Nadine Sachs and Renate Schlömer as well as Junior Professor Florian Stengel and doctoral researcher Carolin Sailer - has discovered that NAC inserts the N-terminal domain of its β-subunit (N-βNAC) deep into the ribosomal tunnel to sense substrates directly upon synthesis and to escort growing polypeptides to the cytosol.

"No other factor we know does that, which is why we were so utterly surprised by our findings. Although NAC was discovered as long as 25 years ago, we are only now beginning to understand how crucial it is for proper cell function. Our study shows that, besides acting as a chaperone both on and off the ribosome, NAC is also able to recognize nascent polypeptide chains deep inside the ribosomal tunnel", says Professor Elke Deuerling, lead author on the study and Professor of Molecular Microbiology at the University of Konstanz. "We already knew NAC to transiently interact with translating ribosomes. But we did not understand how exactly NAC interacts with the ribosome and with nascent substrates to regulate protein folding and transport to the endoplasmic reticulum (ER), which is essential for organismal viability".

The researchers performed biochemical, genetic and structural analyses in the model system C. elegans to attain a more detailed understanding of how NAC identifies and sorts nascent polypeptide chains inside the ribosomal tunnel. "Until quite recently, we assumed that the earliest point of interaction between ribosome-associated factors such as chaperones, enzymes and transport proteins was when the nascent polypeptide chains exit the ribosomal tunnel", explains Dr Martin Gamerdinger, first author on the study alongside Kan Kobayashi, formerly of ETH Zurich and currently an assistant professor at the University of Tokyo. "Usually, at that point, the chains have a length of about 40 amino acids. What we have discovered is that NAC binds to nascent chains as short as ten amino acids or even shorter, and it is doing it inside the tunnel. This makes NAC the very first factor to contact newly synthesized proteins. We even suspect it to be able to sense when the first two amino acids of a nascent protein connect with each other".

As the researchers have been able to show using a combination of cryo-electron microscopy, mass spectrometry and biochemical analyses, including a series of site-specific crosslink experiments, NAC inserts the positively charged and highly flexible N-terminal domain of its β-subunit (N-βNAC) into the ribosomal tunnel, which is for the most part lined by negatively charged ribosomal RNA. "What our study demonstrates is that NAC is able to sense translation activity inside the tunnel and, more importantly, that it is able to sense the character of the proteins that are being synthesized. At least that is our current hypothesis", says Elke Deuerling.

Once they exit the ribosomal tunnel, nascent protein chains can continue down a range of different biogenesis pathways: Some are passed on to other factors that escort these chains to their intended destinations somewhere else inside the cell. Some are modified by enzymes, others require chaperone support to attain their native structural fold. As Martin Gamerdinger comments: "If what we are assuming about the early sensing-mechanism of NAC is correct, then this complex is the single most important protein sorting mechanism that we know of. It would explain how cells manage the complex processes and reactions that take place in connection with nascent polypeptide chains once they exit the ribosomal tunnel". Accordingly, what the researchers plan to verify next is whether the N-βNAC domain can identify the character of nascent proteins inside the ribosomal tunnel and how it prompts them to enter the correct protein biogenesis pathways.

"What we further found is that NAC acts as a molecular filter, preventing inactive ribosomes or ribosomes in the early translational stages from interacting with the translocon of the ER, i.e. with the complex that transports nascent polypeptides with a targeting signal sequence into the endoplasmic reticulum. Unregulated ribosome-translocon interactions could lead to the wrong proteins entering the endoplasmic reticulum on the one hand, and to depletion of protein factors that are in fact needed elsewhere on the other", says Elke Deuerling. "NAC is thus responsible for making the various steps involved in protein biogenesis much more efficient and specific".

While the N-βNAC domain seems to be responsible for sensing and possibly for sorting nascent polypeptide chains, another NAC domain, N-αNAC, interacts with the β-domain and with itself in order to regulate NAC activity on ribosomes. "This, too, is something that we did not know about before", explains Martin Gamerdinger. "Without N-αNAC, NAC would bind too strongly to the ribosome, interfering with the essential protein translation processes taking place there. We have yet to understand how exactly this auto-inhibitory function of NAC works, but what seems clear is that N-αNAC downregulates ribosome binding". As in vivo experiments with C. elegans clearly showed, worms expressing a NAC variant that lacks the auto-inhibition and shows enhanced ribosome binding were developmentally delayed due to reduced protein synthesis rates and impaired translation, clearly showing defects caused by NAC-ribosome misregulation.

Volunteer snorkelers and scuba divers have been helping capture images of reef manta rays to better protect the threatened species.

The University of Queensland initiative - Project Manta - relied on these citizen scientists to photograph or video individual reef manta rays (Mobula alfredi) across Australia's east coast.

UQ PhD candidate Asia Armstrong, who led the study, hopes the data will inform conservation planning and management along the coast.

"Manta rays are a great ambassador species for conservation," Ms Armstrong said.

"Everyone loves them, and they offer a wonderful platform for getting people involved in marine conservation, as people protect what they love.

"With Project Manta, we relied on the cameras and eyes of both trained researchers and volunteers, who helped us build a catalogue of more than 1300 individual reef manta rays, from in excess of 7000 sightings."

Once images and videos were captured, they were analysed to isolate the distances individual rays were travelling.

"Manta rays have a unique spot pattern on their belly, which allows individuals to be identified from one another," Ms Armstrong said.

"Each time an animal is photographed we record the date, time and location of the sighting, along with any additional information, like its sex, maturity status, injuries and behaviour.

"When a sighting is matched to an existing record we gain insights into the ray's movements and population dynamics."

The researchers were surprised to discover that individual rays had travelled from North Stradbroke Island to the wreck of SS Yongala, just south of Townsville, a distance of more than 1,000 kilometres.

"This is a record breaking point-to-point movement for a reef manta ray, improving our understanding of the potential home range for this species," Ms Armstrong said.

"Globally, reef manta rays are listed as vulnerable to extinction, so this information can help inform conservation planning internationally, particularly in regions where this species may be exposed to increased risks and threats.

"It's important now to connect with regional research groups to enable us to compare catalogues, which may reveal longer distance movements than those we've discovered.

"So far, there haven't been any records of cross-jurisdictional movements of this species - that is, movements between the waters of different countries - which is important to know for conservation planning.

"With the help of international researchers, along with passionate citizen scientists and conservationists, we can really improve the long-term chances for this incredible species."

The properties of many materials can change permanently when they are pushed beyond their limits. When a given material is subjected to a force, or 'load', which is stronger than a certain limit, it can become so deformed that it won't return to its original shape, even after the load is removed. However, heavy loads aren't strictly necessary to deform materials irreversibly; this can also occur if they are subjected to lighter loads over long periods of time, allowing a slow process called 'creep' to take place. Physicists have understood for some time that this behaviour involves sequences of small, sudden deformations, but until now, they have lacked a full understanding of how creep deformation affects material properties over time. In new research published in EPJ B, Michael Zaiser and David Castellanos at the University of Erlangen-Nuremberg in Germany analysed the characteristic ways in which material structures evolve during the early stages of creep deformation.

Using computer simulations, the researchers show that this evolution not only modifies material properties; it can also alter the parameters of those properties, meaning the chances of certain events occurring within the material will change. Their work offers physicists important new insights into the long-term behaviours of a wide variety of structural materials under stress, including rocks, porous materials and glass. As well as observing these changes, Zaiser and Castellanos also studied patterns in intervals between deformation events. They found that the events strongly conform to Omori law, which is used by seismologists to calculate time intervals between aftershocks following earthquakes of certain magnitudes.

The duo made their discoveries using computer simulations which modelled creep deformation as a sequence of discrete, randomly activated events. Through their innovative modelling approach, Zaiser and Castellanos have now gathered important insights into how the properties of materials subjected to lighter loads will change over time in the long term.

CABI has led an international team of scientists who strongly suggest that the global trade of forest tree seeds is not as safe as previously believed, with insect pests and fungal pathogens posing a great risk to trees and forest ecosystems worldwide.

Non-native insect pests and fungal pathogens present one of the major threats to trees and forest ecosystems globally, with the potential to cause significant ecological changes and economic losses.

The Asian emerald ash borer, for example, causes large-scale death of ash trees in North America, is also present in Western Russia, and is, therefore, threatening native ash species in Europe. Similarly, the fungal pathogen Cryphonectria parasitica virtually eliminated the native American chestnut from North American forests in the early 20th Century, leading to significant changes in the forest species composition.

Iva Franić, Dr René Eschen and Dr Marc Kenis, along with colleagues from, among other institutions, the Swiss Federal Institute for Forest Snow and Landscape Research (WSL), conducted the first study that simultaneously assessed insects and fungi associated with any type of plants for planting.

In the paper, published in Ecological Applications, the scientists argue that the high infestation rates of seed lots of some tree species is 'alarming' and highlight the need to reconsider phytosanitary measures in trading tree seeds.

The researchers, who assessed insects and fungi in 58 traded seed lots of 11 gymnosperm and angiosperm species from North America, Europe and Asia, using x-ray and DNA analysis, present a range of recommendations to reduce the risks posed by seed-borne pests and fungal pathogens - including the improvement of detection techniques used by phytosanitary inspectors at borders.

Iva Franić, lead author of the study entitled 'Are traded forest seeds a potential source of non-native pests?', said, "The rise of imports of plants for planting from China to Europe increased six-fold from 2000 to 2018 and are now equal to imports from North America." This poses a significant challenge at the border level when trying to prevent new pest or fungal pathogen introductions, which can have a major impact on native tree and forest ecosystems.

High infestation rates of fungi and insects

The research showed both the presence of fungi in all seed lots as well as fungi grown on non-selective agar from 96 percent of the seed lots. Around 30 percent of the seed lots contained insect larvae. The scientists found fungal abundance and diversity to be much higher than insect diversity, especially in angiosperm seeds.

René Eschen (CABI) says, "The trade in seeds of most species is not regulated because seeds are considered less likely to carry harmful organisms than other plants for planting. However, our results demonstrate that seeds contain many insects and fungi."

Simone Prospero (WSL) adds, "The high infestation of commercially supplied seed lots is a clear indication of how often potential pests may be transported via traded seeds. Furthermore, the presence of organisms in these seeds that are already known to be pests indicates that measures should be taken to reduce pest risk."

The scientists say that since fungal pathogens are very difficult to detect during border inspections, there is an urgent need to develop effective treatments for reducing their viability in seeds or regulate the trade in seeds of especially risky origins or species.

Ms Franić concludes, "While only a small number of species identified in the study is of phytosanitary concern, more research is needed to enable better risk assessment, especially to increase knowledge about the potential for transmission of fungi to seedlings and the host range and impact of identified species."

Data from over 12,000 multiple sclerosis (MS) patients formed the basis of a study by the Technical University of Munich (TUM) which investigated the population's vaccination behavior in relation to MS. It showed that five years before their diagnosis, MS patients were statistically less likely to receive vaccinations than comparator groups. Consequently, there was no positive correlation between vaccinations and the development of MS.

MS is now thought to be a neurological autoimmune disease in which the immune system attacks the brain and spinal cord. It is most likely to occur in young people under the age of 40. Vaccinations are often mentioned as a possible risk factor for MS. Professor Bernhard Hemmer, director of the Neurology Department of the TUM hospital, Klinkum rechts der Isar, teamed up with scientists from the Medical Department and the Bavarian Association of Statutory Health Insurance Physicians (KVB) to analyze a large KVB dataset representative of the general population. The data covered over 200,000 individuals, including more than 12,000 MS patients. The study was published in the Tuesday, July 30, 2019, issue of Neurology, the medical journal of the American Academy of Neurology.

Lower vaccination rates among MS patients

The researchers found that five years before being diagnosed, individuals who went on to develop MS had received fewer vaccinations than those who did not develop MS. This applied to all the vaccines investigated: those against pneumococci, meningococci, mumps, measles, rubella, chickenpox, human papilloma virus (HPV), hepatitis A and B, tick-borne encephalitis (TBE) and influenza. The effect was particularly pronounced in the latter three cases: the control group had received significantly more vaccinations than the individuals who later developed MS.

"The causes are still a mystery. It may be that people perceive the disease long before they are diagnosed and therefore avoid putting additional stress on their immune system. Such effects are in fact evident in our data. Or perhaps the vaccines have a protective effect that prevents the immune system from attacking the nervous system. In any case, given the large volume of data analyzed, we can conclusively state that there is no evidence that recent vaccination increases the likelihood of MS or the onset of an initial MS episode", Alexander Hapfelmeier, lead author of the study, explains.

Effect not evident in Crohn's disease or psoriasis

The researchers also wanted to rule out the possibility that the results might be an underlying effect of chronic diseases in general. They therefore analyzed data from two other groups: patients with Crohn's disease, an inflammatory bowel disorder, and patients with psoriasis, a chronic skin disease. The vaccinations of these patients had also been recorded five years before their diagnosis.

Those patients, however, had received as many vaccinations as the healthy control group. "Thus, the results are not due solely to the presence of a chronic inflammatory disease, but to behavior specific to MS," Bernhard Hemmer says, adding: "We already know from other studies that MS sufferers show atypical behavior and medical history long before they are diagnosed. For example, they are more prone to mental illnesses and also tend to have fewer children. All this clearly indicates that MS is perceived long before any neurological symptoms appear. We therefore need to find suitable markers to diagnose the condition earlier. We see this as one of our most important tasks."